阅读说明：本技术 图像形成设备 (Image forming apparatus with a toner supply unit ) 是由 市来幸裕 下平彬 桥本敬太 合田峻广 須藤真树 于 2019-09-03 设计创作，主要内容包括：本发明提供一种图像形成设备,包括传送带、第一中间转印带以及第二中间转印带。所述传送带沿着在竖向上延伸的传送路径设置。所述传送带被构造成在与记录介质的一个表面接触的同时传送所述记录介质。所述第一中间转印带被构造成与所述传送带一起夹持所述记录介质。图像从所述第一中间转印带转印到所述记录介质。所述第二中间转印带设置在所述第一中间转印带上方。所述第二中间转印带构造成与所述传送带一起夹持处于夹在所述第一中间转印带和所述传送带之间的状态下的所述记录介质。图像从所述第二中间转印带转印到所述记录介质。(The invention provides an image forming apparatus including a conveyor belt, a first intermediate transfer belt, and a second intermediate transfer belt. The conveyor belt is disposed along a conveying path extending in a vertical direction. The conveying belt is configured to convey a recording medium while being in contact with one surface of the recording medium. The first intermediate transfer belt is configured to nip the recording medium together with the conveyor belt. An image is transferred from the first intermediate transfer belt to the recording medium. The second intermediate transfer belt is disposed above the first intermediate transfer belt. The second intermediate transfer belt is configured to nip the recording medium in a state of being sandwiched between the first intermediate transfer belt and the conveyor belt together with the conveyor belt. An image is transferred from the second intermediate transfer belt to the recording medium.)

1. An image forming apparatus, comprising:

a conveyor belt disposed along a conveying path extending in a vertical direction, the conveyor belt being configured to convey a recording medium while being in contact with one surface of the recording medium;

a first intermediate transfer belt configured to nip the recording medium with the conveyor belt, an image being transferred from the first intermediate transfer belt to the recording medium; and

a second intermediate transfer belt disposed above the first intermediate transfer belt, the second intermediate transfer belt being configured to nip the recording medium in a state of being sandwiched between the first intermediate transfer belt and the conveyor belt together with the conveyor belt, an image being transferred from the second intermediate transfer belt to the recording medium.

2. The image forming apparatus according to claim 1, further comprising:

a first image forming unit including the first intermediate transfer belt; and

a second image forming unit disposed above the first image forming unit and including the second intermediate transfer belt, wherein,

an upper end of the first image forming unit overlaps the second image forming unit when viewed in a horizontal direction.

3. The image forming apparatus according to claim 2,

the first image forming unit includes a circuit board disposed above the first intermediate transfer belt, and

an upper end of the circuit board overlaps the second image forming unit when viewed in the horizontal direction.

4. An image forming apparatus according to any one of claims 1 to 3, wherein the first intermediate transfer belt and the second intermediate transfer belt are inclined in the same direction with respect to a contact surface of the conveyance belt with the recording medium.

5. An image forming apparatus according to claim 4, wherein a lower end of the first intermediate transfer belt and an upper end of the second intermediate transfer belt are disposed within a height of the conveying belt in an up-down direction.

6. The image forming apparatus according to claim 4 or 5, further comprising:

two pairs of rollers, wherein,

each of the first intermediate transfer belt and the second intermediate transfer belt is wound around a corresponding one of the two pairs of rollers,

each of the two pairs of rollers comprises:

a first roller facing the conveyor belt via a respective one of the first intermediate transfer belt and the second intermediate transfer belt; and

a second roller disposed on an opposite side of the first roller from the conveyor belt.

7. The image forming apparatus according to any one of claims 1 to 6, further comprising:

a charge applying unit provided between (i) a first transfer position at which the image is transferred from the first intermediate transfer belt and (ii) a second transfer position at which the image is transferred from the second intermediate transfer belt, the charge applying unit being configured to apply, to the conveying belt, a charge that attracts the recording medium to the conveying belt.

8. The image forming apparatus according to claim 7, wherein the electric charge applying unit is provided on an opposite surface of the conveying belt to a contact surface of the conveying belt with the recording medium.

9. The image forming apparatus according to claim 7 or 8, wherein the charge applying unit applies the charge to the conveying belt when the conveying belt conveys a second recording medium thinner than a first recording medium as the recording medium.

10. The image forming apparatus according to any one of claims 1 to 9, further comprising:

a drive roller wrapped around the conveyor belt, the drive roller configured to drive and rotate the conveyor belt, wherein,

(i) a distance between a first transfer position where the image is transferred from the first intermediate transfer belt and (ii) a second transfer position where the image is transferred from the second intermediate transfer belt is an integral multiple of a circumference of the drive roller.

11. An image forming apparatus, comprising:

a plurality of image forming bodies, each image forming body including:

a plurality of image forming sections; and

a primary intermediate transfer body to which the images formed by the plurality of image forming portions are primarily transferred; a plurality of secondary transfer units provided on the plurality of image-formed bodies, respectively, the secondary transfer units being configured to secondarily transfer the images of the primary intermediate transfer bodies sequentially in a recording medium conveyance direction; and

a charge removing unit provided between the plurality of secondary transfer units, the charge removing unit being configured to remove charges of the recording medium charged in any of the secondary transfer units.

12. The image forming apparatus according to claim 11, further comprising:

a conveying belt configured to convey the recording medium to the plurality of secondary transfer units, wherein,

the conveyor belt is formed into a loop,

the conveying belt conveys the recording medium while an outer peripheral surface of the conveying belt is in contact with one surface of the recording medium,

the charge removing unit is disposed inside the conveyor belt, and

the charge removing unit removes the charge of the recording medium via the conveyor belt.

13. An apparatus according to claim 12, wherein said charge removing unit is a driven roller which is in contact with an inner peripheral surface of said conveying belt and is driven and rotated by said conveying belt.

14. The image forming apparatus according to any one of claims 11 to 13,

the conveying belt conveys the recording medium from a lower side to an upper side in a gravity direction, and

the first intermediate transfer belt and the second intermediate transfer belt vertically overlap each other in the gravitational direction.

15. The image forming apparatus according to any one of claims 11 to 14, wherein the charge removing unit applies a charge opposite in polarity to the recording medium charged at the first transfer position to the recording medium by being applied with a voltage.

16. The image forming apparatus according to claim 15, further comprising:

a receiving unit configured to receive information about the recording medium, wherein,

the voltage applied to the charge removing unit is changed based on the information received by the receiving unit.

17. The image forming apparatus according to any one of claims 11 to 15,

the charge removing unit is disposed on a non-image surface side opposite to an image surface of the recording medium, and

the charge removing unit is controlled such that the charge removing unit performs charge removal when the recording medium has a high resistance.

Technical Field

The present disclosure relates to an image forming apparatus.

Background

Japanese patent laid-open No. 2009-86517 discloses an image forming apparatus including a conveyance belt that conveys a sheet in a vertical direction and a suction roller that sucks the sheet to the conveyance belt.

Disclosure of Invention

Aspects of non-limiting embodiments of the present disclosure are directed to providing an image forming apparatus capable of forming a multicolor image using a plurality of intermediate transfer belts.

According to a first aspect of the present disclosure, there is provided an image forming apparatus including: a conveyor belt disposed along a conveying path extending in a vertical direction, the conveyor belt being configured to convey a recording medium while being in contact with one surface of the recording medium; a first intermediate transfer belt configured to nip the recording medium with the conveyor belt, an image being transferred from the first intermediate transfer belt to the recording medium; and a second intermediate transfer belt disposed above the first intermediate transfer belt, the second intermediate transfer belt being configured to nip the recording medium in a state of being sandwiched between the first intermediate transfer belt and the conveyor belt together with the conveyor belt, an image being transferred from the second intermediate transfer belt to the recording medium.

According to a second aspect of the present disclosure, the image forming apparatus according to the first aspect further includes: a first image forming unit including the first intermediate transfer belt; and a second image forming unit that is disposed above the first image forming unit and includes the second intermediate transfer belt, wherein an upper end of the first image forming unit overlaps the second image forming unit when viewed in a horizontal direction.

According to a third aspect of the present disclosure, in the image forming apparatus according to the second aspect, the first image forming unit includes a circuit board disposed above the first intermediate transfer belt, and an upper end of the circuit board overlaps the second image forming unit when viewed in the horizontal direction.

According to a fourth aspect of the present disclosure, in the image forming apparatus according to any one of the first to third aspects, the first intermediate transfer belt and the second intermediate transfer belt are inclined in the same direction with respect to a contact surface of the transfer belt with the recording medium.

According to a fifth aspect of the present disclosure, in the image forming apparatus according to the fourth aspect, a lower end of the first intermediate transfer belt and an upper end of the second intermediate transfer belt are disposed within a height of the conveyor belt in an up-down direction.

According to a sixth aspect of the present disclosure, the image forming apparatus according to any one of the fourth to fifth aspects further includes two pairs of rollers, wherein each of the first intermediate transfer belt and the second intermediate transfer belt is wound around a corresponding one of the two pairs of rollers, each of the two pairs of rollers including: a first roller facing the conveyor belt via a respective one of the first intermediate transfer belt and the second intermediate transfer belt; and a second roller disposed on an opposite side of the first roller from the conveyor belt.

According to a seventh aspect of the present disclosure, the image forming apparatus according to any one of the first to sixth aspects further includes: a charge applying unit provided between (i) a first transfer position at which the image is transferred from the first intermediate transfer belt and (ii) a second transfer position at which the image is transferred from the second intermediate transfer belt, the charge applying unit being configured to apply, to the conveying belt, a charge that attracts the recording medium to the conveying belt.

According to an eighth aspect of the present disclosure, in the image forming apparatus according to the seventh aspect, the electric charge applying unit is provided on an opposite surface of the conveying belt to a contact surface of the conveying belt with the recording medium.

According to a ninth aspect of the present disclosure, in the image forming apparatus according to any one of the seventh to eighth aspects, the electric charge applying unit applies electric charge to the conveying belt when the conveying belt conveys a second recording medium thinner than a first recording medium as the recording medium.

According to a tenth aspect of the present disclosure, the image forming apparatus according to any one of the first to ninth aspects further includes a drive roller wound by the conveyance belt, the drive roller being configured to drive and rotate the conveyance belt, wherein a distance between (i) a first transfer position where the image is transferred from the first intermediate transfer belt and (ii) a second transfer position where the image is transferred from the second intermediate transfer belt is an integral multiple of a circumference of the drive roller.

According to an eleventh aspect of the present disclosure, there is provided an image forming apparatus comprising: a plurality of image forming bodies each including a plurality of image forming portions and a primary intermediate transfer body onto which images formed by the plurality of image forming portions are primarily transferred; a plurality of secondary transfer units provided on the plurality of image-formed bodies, respectively, the secondary transfer units being configured to secondarily transfer the images of the primary intermediate transfer bodies sequentially in a recording medium conveyance direction; and a charge removing unit provided between the plurality of secondary transfer units, the charge removing unit being configured to remove charges of the recording medium charged in any of the secondary transfer units.

According to a twelfth aspect of the present disclosure, the image forming apparatus according to the eleventh aspect further comprises: a conveying belt configured to convey the recording medium to the plurality of secondary transfer units, wherein the conveying belt is formed in a loop shape, the conveying belt conveys the recording medium while an outer circumferential surface of the conveying belt is in contact with one surface of the recording medium, the electric charge removing unit is disposed inside the conveying belt, and the electric charge removing unit removes the electric charge of the recording medium via the conveying belt.

According to a thirteenth aspect of the present disclosure, in the image forming apparatus according to the twelfth aspect, the charge removing unit is a driven roller that is in contact with an inner peripheral surface of the conveying belt and is driven and rotated by the conveying belt.

According to a fourteenth aspect of the present disclosure, in the image forming apparatus according to any one of the eleventh to thirteenth aspects, the conveying belt conveys the recording medium from a lower side to an upper side in a gravitational direction, and the first intermediate transfer belt and the second intermediate transfer belt vertically overlap each other in the gravitational direction.

According to a fifteenth aspect of the present disclosure, in the image forming apparatus according to any one of the eleventh to fourteenth aspects, the charge removing unit applies, to the recording medium, a charge of a polarity opposite to that of the recording medium charged at the first transfer position by being applied with a voltage.

According to a sixteenth aspect of the present disclosure, the image forming apparatus according to the fifteenth aspect further comprises: a receiving unit configured to receive information about the recording medium, wherein a voltage applied to the charge removing unit is changed based on the information received by the receiving unit.

According to a seventeenth aspect of the present disclosure, in the image forming apparatus according to any one of the eleventh to fifteenth aspects, the charge removing unit is disposed on a non-image surface side opposite to an image surface of the recording medium, and the charge removing unit is controlled such that the charge removing unit performs charge removal when the recording medium has a high resistance.

With the configuration of the first aspect, the space between the first intermediate transfer belt and the second intermediate transfer belt can be reduced and images can be transferred to the recording medium at a plurality of positions, as compared with a configuration in which only the recording medium is sandwiched between the transfer belt and a single intermediate transfer belt.

With the configuration of the second aspect, the space between the first intermediate transfer belt and the second intermediate transfer belt can be reduced as compared with a configuration in which the upper end of the first image forming unit is lower than the lower end of the second image forming unit.

With the configuration of the third aspect, the space between the first intermediate transfer belt and the second intermediate transfer belt can be reduced as compared with a configuration in which the upper end of the circuit board is lower than the lower end of the second image forming unit.

With the configuration of the fourth aspect, the space between the first intermediate transfer belt and the second intermediate transfer belt can be reduced as compared with a configuration in which the first intermediate transfer belt and the second intermediate transfer belt are inclined in different directions with respect to the contact surfaces.

With the configuration of the fifth aspect, the space between the first intermediate transfer belt and the second intermediate transfer belt can be reduced as compared with a configuration in which the lower end of the first intermediate transfer belt and the upper end of the second intermediate transfer belt are arranged outside the height of the transfer belts in the up-down direction.

With the configuration of the sixth aspect, the dimension in the height direction of each of the first intermediate transfer belt and the second intermediate transfer belt can be reduced as compared with a configuration in which each of the first intermediate transfer belt and the second intermediate transfer belt is wound around three or more rollers.

With the configuration of the seventh aspect, the recording medium that has passed through the first transfer position can be prevented from being separated from the conveyance belt, as compared with a configuration in which the conveyance belt conveys the recording medium in a state in which no electric charge is applied to the conveyance belt between the first conveyance position and the second conveyance position.

With the configuration of the eighth aspect, for the recording medium conveyed by the conveyor belt, the recording medium can be attracted to the conveyor belt in a non-contact manner.

With the configuration of the ninth aspect, the second recording medium thinner than the first recording medium can be prevented from being separated from the conveyor belt after passing through the first transfer position, as compared with a configuration in which the conveyor belt conveys the recording medium in a state in which no electric charge is applied to the conveyor belt between the first conveyance position and the second conveyance position.

With the configuration of the tenth aspect, transfer deviation between the first transfer position and the second transfer position due to eccentricity of the drive roller can be prevented, as compared with a configuration in which the distance between the first transfer position and the second transfer position is different from an integral multiple of the circumferential length of the drive roller.

With the configuration of the eleventh aspect, it is possible to prevent an influence on transferability of an image at the second transfer position, as compared with a configuration in which a recording medium is conveyed to the second transfer position while the first transfer position is in a charged state.

With the configuration of the twelfth aspect, the charge removing unit can remove the charge of the recording medium conveyed by the conveyor belt without contacting the recording medium.

With the configuration of the thirteenth aspect, the frictional resistance with the conveyance belt can be reduced as compared with a configuration in which the charge removing unit slides with respect to the conveyance belt.

With the configuration of the fourteenth aspect, the size in the horizontal direction of the image forming apparatus can be reduced and the influence on the transferability of the image at the second transfer position can be prevented, as compared with a configuration in which the recording medium is conveyed by the conveyor belt in the horizontal direction and the entire first intermediate transfer belt is arranged offset in the horizontal direction with respect to the second intermediate transfer belt.

With the configuration of the fifteenth aspect, the ability of the charge removing unit to remove electric charges can be improved as compared with a configuration in which the charge removing unit is grounded to a reference potential (ground) and serves as a ground that simply discharges electric charges of the recording medium.

With the configuration of the sixteenth aspect, the charge removing capability of the charge removing unit can be changed according to the recording medium, as compared with a configuration in which a constant voltage is applied to the charge removing unit.

Drawings

Exemplary embodiments of the present disclosure will be described in detail based on the following drawings, in which:

fig. 1 is a schematic diagram showing a configuration of an image forming apparatus according to a first exemplary embodiment;

fig. 2 is a schematic view showing the configuration of a conveying belt, a first image forming unit, and a second image forming unit according to the first exemplary embodiment;

fig. 3 is a perspective view showing the configuration of a first image forming unit (second image forming unit) according to the first exemplary embodiment;

fig. 4 is a schematic diagram showing a control system that controls the operation of the charge applying roller according to the first exemplary embodiment;

fig. 5 is a schematic view showing the configuration of the conveyor belt, the first intermediate transfer belt, and the second intermediate transfer belt according to the first exemplary embodiment;

FIG. 6 is a schematic view showing a configuration of a second image forming unit according to a modification;

fig. 7 is a schematic diagram showing a configuration of an image forming apparatus according to a second exemplary embodiment;

fig. 8 is a schematic view showing the configuration of a conveying belt, a first image forming unit, and a second image forming unit according to a second exemplary embodiment;

fig. 9 is a perspective view showing the configuration of a first image forming unit (second image forming unit) according to a second exemplary embodiment; and

fig. 10 is a schematic diagram showing a control system that controls the operation of the charge removing roller according to the second exemplary embodiment.

Detailed Description

Hereinafter, exemplary embodiments according to the present disclosure will be described based on the drawings.

In addition, an arrow UP shown in the drawing indicates an upper side (vertically upper side) of the device, and an arrow DO indicates a lower side (vertically lower side) of the device. Further, an arrow LH shown in the figure indicates the left side of the device, and an arrow RH indicates the right side of the device. Further, arrow FR shown in the drawing indicates the front side of the apparatus, and arrow RR indicates the rear side of the apparatus. Since these directions are directions defined for convenience of description, the device configuration is not limited to these directions.

Further, the direction along the upper and lower sides of the apparatus may be referred to as a vertical direction of the apparatus. The vertical direction of the device is also the direction of gravity. Further, directions along the left and right sides of the device may be referred to as left and right directions of the device. The left-right direction of the apparatus is also the width direction (horizontal direction) of the device. Further, the directions along the front and rear sides of the apparatus may be referred to as the front-rear direction of the apparatus. The front-rear direction of the apparatus is also the depth direction (horizontal direction) of the apparatus. In addition, the word "device" may be omitted in every direction of the device. That is, for example, the "upper side of the apparatus" may be simply referred to as "upper side".

Further, the symbol with an "x" in "○" in the drawing indicates an arrow from the front to the rear of the sheet, and further, the symbol with an "in" ○ "in the drawing indicates an arrow from the rear to the front of the sheet.

Image forming apparatus 10

The configuration of the image forming apparatus 10 according to the first exemplary embodiment will be described. Fig. 1 is a schematic diagram showing the configuration of an image forming apparatus 10 according to a first exemplary embodiment.

The image forming apparatus 10 shown in fig. 1 is an embodiment of an image forming apparatus that forms an image on a recording medium. Specifically, the image forming apparatus 10 is an electrophotographic image forming apparatus that forms a toner image (an example of an image) on a recording medium P. More specifically, as shown in fig. 1, the image forming apparatus 10 includes an apparatus main body 11, an accommodating unit 12, a discharging unit 18, a conveying unit 13, an image forming device 14, a fixing device 19, and charge applying rollers 81 and 82. Each unit (the apparatus main body 11, the accommodating unit 12, the discharging unit 18, the conveying unit 13, the image forming device 14, the fixing device 19, and the charge applying rollers 81 and 82) of the image forming apparatus 10 will be described.

(apparatus body 11, accommodation unit 12 and discharge unit 18)

The apparatus main body 11 shown in fig. 1 has a function of accommodating each component therein. The apparatus main body 11 is configured with, for example, a box-shaped housing.

The accommodating unit 12 has a function of accommodating a recording medium P such as a sheet. As shown in fig. 1, the accommodating unit 12 is provided at a lower portion inside the apparatus main body 11. In the first exemplary embodiment, the recording medium P is accommodated in the accommodating unit 12 by being stacked in the accommodating unit 12.

The discharge unit 18 has a function of discharging the recording medium P on which the toner image has been formed. As shown in fig. 1, the discharge unit 18 is provided in an upper region of the apparatus body 11. In the first exemplary embodiment, the recording medium P discharged toward the discharge unit 18 is stacked on the discharge unit 18.

(transfer unit 13)

The conveying unit 13 shown in fig. 1 has a function of conveying the recording medium P. Specifically, the conveying unit 13 has a function of conveying the recording medium P along a conveying path 38 extending in the vertical direction. More specifically, the conveying unit 13 has a function of conveying the recording medium P upward from the accommodating unit 12 to the discharge unit 18 in the conveying path 38.

For further description, as shown in fig. 1, the conveying unit 13 includes a delivery roller 32, a plurality of conveying rollers 34, a conveying belt 20, and a discharge roller 36. The delivery roller 32 is a roller that delivers the recording medium P accommodated in the accommodating unit 12. The plurality of conveying rollers 34 are rollers that convey the recording medium P delivered by the delivery roller 32 toward the conveying belt 20.

The conveyor belt 20 is disposed along a vertically extending conveying path 38. The conveyor belt 20 has a function of conveying the recording medium P by contacting one surface of the recording medium P.

Specifically, the conveyor belt 20 is in the shape of a belt having a width in the front-rear direction, and is formed in an endless shape. More specifically, the conveyor belt 20 is formed, for example, in an endless shape without an end portion.

For further description, the conveyor belt 20 is wrapped around a pair of rollers 22. Specifically, the conveyor belt 20 is wound in a state where tension is applied to a pair of rollers 22 spaced apart from each other at a certain distance in the up-down direction (vertical direction). More specifically, the conveyor belt 20 is wound in a state in which tension is applied to a driven roller 22A disposed in a lower portion inside the apparatus main body 11 and a driving roller 22B disposed above the driven roller 22A as a pair of rollers 22. In the first exemplary embodiment, when the driving roller 22B is rotated in one direction (the direction of the arrow a) by, for example, a motor 68 of a second image forming unit 42 which will be described later, the conveying belt 20 is circulated in one direction (the direction of the arrow B).

To further describe, the conveying belt 20 has a function of conveying the recording medium P by contacting a non-image surface of the recording medium P at its outer peripheral surface. Specifically, the conveying belt 20 is in contact with the non-image surface of the recording medium P at a contact surface 20A facing the left side of the outer peripheral surface (the first intermediate transfer belt 71 and the second intermediate transfer belt 72 side to be described later) to convey the recording medium P. Further, specifically, the contact surface 20A is a surface linearly extending in the vertical direction. Further, the non-image surface of the recording medium P is a surface opposite to the image surface on which the toner image is formed. As described above, in the first exemplary embodiment, the conveying belt 20 is configured to convey the recording medium P from the lower side to the upper side in the direction of gravity.

The discharge roller 36 is a roller that discharges the recording medium P, which has been conveyed by the conveyor belt 20 and then passed through the fixing device 19, to the discharge unit 18.

As described above, the conveying unit 13 conveys the recording medium P upward. Therefore, in the conveying unit 13, the upward direction is regarded as the conveying direction. Further, in the conveyance unit 13, the lower side is the upstream side in the conveyance direction, and the upper side is the downstream side in the conveyance direction.

(image Forming apparatus 14)

The image forming apparatus 14 shown in fig. 1 has a function of forming a toner image (an example of an image) on a recording medium P. Specifically, as shown in fig. 1, the image forming apparatus 14 includes a first image forming unit 41, a second image forming unit 42, and two secondary transfer rollers 47 and 48. The first image forming unit 41 is an embodiment of the first image forming unit. The second image forming unit 42 is an embodiment of a second image forming unit.

Hereinafter, the configurations of the first image forming unit 41, the second image forming unit 42, and the two secondary transfer rollers 47 and 48 will be described. Further, the arrangement of constituent units (components) constituting the image forming apparatus 14 will be described.

[ first image Forming Unit 41]

As shown in fig. 1, the first image forming unit 41 is disposed at a lower portion inside the apparatus main body 11. As shown in fig. 2 and 3, the first image forming unit 41 includes a unit main body 60, four toner image forming portions 50, four primary transfer rollers 75, a first intermediate transfer belt 71, a motor 68, a power supply substrate 62, a control board 64, and a high-voltage power supply substrate 66.

Specifically, the first image forming unit 41 includes toner image forming portions 50 for a total of four colors of yellow (Y), magenta (M), cyan (C), and white (W) as four toner image forming portions 50. Reference numerals "Y", "M", "C", and "W" shown in fig. 2 denote parts corresponding to the respective colors. Further, since the toner image forming portions 50 of the respective colors are configured in the same manner except for the toner, each component of the toner image forming portion 50(Y) in fig. 2 is given the same reference numeral representing the toner image forming portion 50 of each color. Hereinafter, each component of the first image forming unit 41 (the unit main body 60, the four toner image forming portions 50, the four primary transfer rollers 75, the first intermediate transfer belt 71, the motor 68, the power supply substrate 62, the control board 64, and the high-voltage power supply substrate 66) will be described.

[ Unit body 60]

The unit main body 60 shown in fig. 3 serves as a support body that supports each component of the first image forming unit 41. The unit main body 60 is configured with a frame formed of, for example, a sheet metal. As shown in fig. 3, the unit body 60 includes, for example, an upper wall 60U, a front wall 60F, a rear wall 60R, and a left wall 60L (side wall). In fig. 2, the front wall 60F and the left wall 60L (side walls) are omitted.

[ toner image Forming portion 50]

As shown in fig. 2, the toner image forming portion 50 of each color includes a photosensitive drum 52 (photoconductor) that rotates in one direction (the direction of arrow E). Further, the toner image forming portion 50 of each color includes a charging device 53, an exposure device 54, a developing device 56, and a removing device 58.

In the toner image forming portion 50 of each color, a charging device 53 charges a photosensitive drum 52. Further, the exposure device 54 exposes the photosensitive drum 52 charged by the charging device 53 to form an electrostatic latent image on the photosensitive drum 52. Further, the developing device 56 develops the electrostatic latent image formed on the photosensitive drum 52 by the exposure device 54 to form a toner image. The removing device 58 is configured with a blade that removes toner remaining on the photosensitive drum 52 after the toner image is transferred onto a first intermediate transfer belt 71, which will be described later.

[ Primary transfer roller 75]

As shown in fig. 2, four primary transfer rollers 75 are disposed inside (on the inner peripheral side) the first intermediate transfer belt 71. Specifically, each of the four primary transfer rollers 75 is disposed to face the photosensitive drum 52 of the corresponding color via the first intermediate transfer belt 71.

Each of the primary transfer rollers 75 has a function of transferring the toner image on the photosensitive drum 52 of the corresponding color onto the first intermediate transfer belt 71 at a primary transfer position T1 between the photosensitive drum 52 and the primary transfer roller 75. In the exemplary embodiment, the toner image formed on the photosensitive drum 52 is transferred onto the first intermediate transfer belt 71 at the primary transfer position T1 by applying a primary transfer electric field between the primary transfer roller 75 and the photosensitive drum 52. In this way, the toner images on the photosensitive drums 52 of the respective colors are primarily transferred onto the first intermediate transfer belt 71 in an overlapping manner.

[ first intermediate transfer Belt 71]

The first intermediate transfer belt 71 has a function of holding the toner image transferred from the photosensitive drum 52 of each color of the first image forming unit 41. Further, the first intermediate transfer belt 71 has a function of conveying the held toner image to a first secondary transfer position T21 which will be described later. Specifically, the first intermediate transfer belt 71 is configured as follows.

The first intermediate transfer belt 71 is in the shape of a belt having a width in the front-rear direction, and is formed in an endless shape. Specifically, the first intermediate transfer belt 71 is formed, for example, in an endless shape without an end portion.

For further description, the first intermediate transfer belt 71 is wound around a pair of rollers 74. The pair of rollers 74 includes: a drive roller 74A (an example of a first roller) facing the conveyance belt 20 via the first intermediate transfer belt 71; and a driven roller 74B (an embodiment of a second roller) provided to the conveying belt 20 on the opposite side (left side) of the driving roller 74A. Then, the first intermediate transfer belt 71 is wound around only the driving roller 74A and the driven roller 74B in a tensioned state. In the first exemplary embodiment, when the drive roller 74A is rotated in one direction (the direction of arrow C) by the motor 68, the first intermediate transfer belt 71 is circulated in one direction (the direction of arrow D). In addition, the drive roller 74A serves as an opposing roller (support roller) of the secondary transfer roller 48.

The first intermediate transfer belt 71 has a contact area 71N (nip area), and the contact area 71N is in contact with the transfer belt 20 in a portion wound around the driving roller 74A. The contact area 71N is a first secondary transfer position T21 at which the toner image on the first intermediate transfer belt 71 is transferred onto the recording medium P at the first secondary transfer position T21. Further, the first intermediate transfer belt 71 nips and conveys the recording medium P in the contact area 71N together with the conveyance belt 20. The first secondary transfer position T21 is an example of the first transfer position.

The first image forming unit 41 includes a removing unit 78, and the removing unit 78 removes toner remaining on the first intermediate transfer belt 71 after the toner image is transferred onto the recording medium P. The removing unit 78 is configured with a blade provided between the high voltage power supply substrate 66 and the conveyor belt 20 on the upper side of the first intermediate transfer belt 71. The counter roller 79 is disposed below the removing unit 78 so as to face the removing unit 78 via the first intermediate transfer belt 71.

[ Motor 68]

As shown in fig. 3, a motor 68 is provided on the rear wall 60R of the unit main body 60 in the first image forming unit 41. The motor 68 serves as a driving source that drives the driving member of the first image forming unit 41. Specifically, the motor 68 drives, for example, the photosensitive drum 52, the developing roller 56A of the developing device 56, and the driving roller 74A wound by the first intermediate transfer belt 71 via a gear train (not shown). Further, the driving force of the motor 68 is transmitted to, for example, the delivery roller 32 and the plurality of conveyance rollers 34 of the conveyance unit 13, so that the delivery roller 32 and the plurality of conveyance rollers 34 are driven to rotate.

[ Power supply substrate 62, control board 64, and high-voltage power supply substrate 66]

As shown in fig. 2 and 3, a power supply substrate 62, a control board 64, and a high-voltage power supply substrate 66 are disposed on the top of the unit main body 60. The power substrate 62 is an embodiment of a circuit board.

The power supply substrate 62 has a function of receiving power supplied from an external power supply (not shown) of the image forming apparatus 10 via a wire (not shown) and supplying power of a predetermined voltage to the motor 68 and the like. The power supply substrate 62 includes an electronic component 62A on its upper surface.

The control board 64 has a function of controlling the driving of each component of the first image forming unit 41. The control board 64 includes a recording unit configured with, for example: a ROM or memory in which the program is recorded; and a processor operating according to the program. The control board 64 includes electronic components 64A on its upper surface.

As shown in fig. 4, a user interface 17 (hereinafter, referred to as a UI17) as an operation unit is connected to the control board 64. The UI17 is configured with, for example, a liquid crystal display with a touch panel. Operation buttons (virtual buttons) and information to be notified to an operator (user) are displayed on a screen of the UI.

The operator operates the operation buttons via the UI17 to specify image forming conditions including selection of the type of the recording medium P. Further, the operation unit may be, for example, a Personal Computer (PC) connected to the image forming apparatus 10 via a network as long as the operation unit can specify the image forming conditions.

The high-voltage power supply substrate 66 has a function of receiving electric power supplied from an external power supply (not shown) of the image forming apparatus 10 via electric wires (not shown) and supplying electric power having a voltage higher than that of the power supply substrate 62 to the charging device 53, the developing device 56, the four primary transfer rollers 75, the secondary transfer rollers 47 and 48, the charge application rollers 81 and 82, and the like. The high-voltage power supply substrate 66 includes an electronic component 66A on a lower surface thereof. In addition, the high voltage power supply substrate 66 may be configured to receive power supplied from the power supply substrate 62.

[ second image Forming Unit 42]

The second image forming unit 42 is disposed in an upper region inside the apparatus main body 11. In the first exemplary embodiment, the second image forming unit 42 is configured in the same manner as the first image forming unit 41.

Specifically, the second image forming unit 42 includes a unit main body 60, four toner image forming portions 50, four primary transfer rollers 75, a second intermediate transfer belt 72, a motor 68, a power supply substrate 62, a control board 64, and a high-voltage power supply substrate 66.

The second image forming unit 42 includes toner image forming portions 50 for a total of four colors of transparent color (T), silver color (S), gold color (G), and black color (K) as four toner image forming portions 50. Reference numerals "T", "S", "G", and "K" shown in fig. 2 denote parts corresponding to the respective colors. Further, since the toner image forming portions 50 of the respective colors are configured in the same manner except for the toners used, each component of the toner image forming portion 50(T) in fig. 2 is given the same reference numeral representing the toner image forming portion 50 of each color. Hereinafter, since the toner image forming portion 50 of the second image forming unit 42 is configured in the same manner as the toner image forming portion 50 of the first image forming unit 41, the description thereof will be omitted.

Further, since each of the unit main body 60, the four primary transfer rollers 75, the power supply substrate 62, the control board 64, and the high-voltage power supply substrate 66 in the second image forming unit 42 is configured in the same manner as each of the unit main body 60, the four primary transfer rollers 75, the power supply substrate 62, the control board 64, and the high-voltage power supply substrate 66 in the first image forming unit 41, description thereof will be omitted.

The motor 68 in the second image forming unit 42 drives, for example, the photosensitive drum 52, the developing roller 56A of the developing device 56, and the driving roller 74A wound around the second intermediate transfer belt 72 via a gear train (not shown), for example. Further, the driving force of the motor 68 is transmitted to, for example, the driving roller 22B of the conveying belt 20 and a heating roller 92 of the fixing device 19, which will be described later, so that the driving roller 22B and the heating roller 92 are driven to rotate. In addition, the same reference numerals are appropriately given to each component of the second image forming unit 42 having the same function as each component of the first image forming unit 41.

[ second intermediate transfer belt 72]

The second intermediate transfer belt 72 is configured in the same manner as the first intermediate transfer belt 71 of the first image forming unit 41, and is wound around only a pair of rollers 74 including a driving roller 74A (an example of a first roller) and a driven roller 74B (an example of a second roller). The second intermediate transfer belt 72 has a function of holding the toner image transferred from the photosensitive drum 52 of each color of the second image forming unit 42 and conveying the toner image to the second secondary transfer position T22.

Specifically, the second intermediate transfer belt 72 includes a contact area 72N (nip area), and the contact area 72N is in contact with the transfer belt 20 in a portion wound around the drive roller 74A. The contact area 72N is a second secondary transfer position T22 at which the toner image on the second intermediate transfer belt 72 is transferred onto the recording medium P at the second secondary transfer position T22. In addition, the second secondary transfer position T22 is an example of the second transfer position.

Further, the second intermediate transfer belt 72 has a function of nipping the recording medium P in a contact area 72N together with the conveyor belt 20 in a state of being nipped between the first intermediate transfer belt 71 and the conveyor belt. In other words, the second intermediate transfer belt 72 has a function of nipping the recording medium P together with the transfer belt 20 simultaneously with the first intermediate transfer belt 71.

Specifically, in the first exemplary embodiment, when the recording medium P is conveyed by the conveyor belt 20, first, the recording medium P is sandwiched between the first intermediate transfer belt 71 and the conveyor belt 20, and is not sandwiched between the second intermediate transfer belt 72 and the conveyor belt 20. Then, the recording medium P is sandwiched between the first intermediate transfer belt 71 and the conveyor belt 20, and between the second intermediate transfer belt 72 and the conveyor belt 20, in the course of being conveyed by the conveyor belt 20. Further, the recording medium P is not sandwiched between the first intermediate transfer belt 71 and the conveyor belt 20, and is sandwiched between the second intermediate transfer belt 72 and the conveyor belt 20 in the process of being conveyed by the conveyor belt 20. In other words, the leading end of the recording medium P enters the second secondary transfer position T22 before the trailing end of the recording medium P leaves the first secondary transfer position T21.

In the first exemplary embodiment, the second intermediate transfer belt 72 and the conveyor belt 20 sandwich the recording medium P in a state where the recording medium P of a standard size (for example, a4 size) is sandwiched between the first intermediate transfer belt 71 and the conveyor belt 20. The standard size can be said to be the most common size. In addition, the second intermediate transfer belt 72 and the conveyor belt 20 can nip the recording medium P in a state where the recording medium P of any size (including the smallest-sized recording medium that can be conveyed by the image forming apparatus 10) is sandwiched between the first intermediate transfer belt 71 and the conveyor belt 20. To further describe, in the first exemplary embodiment, the second intermediate transfer belt 72 and the conveyor belt 20 may nip the recording medium P at least in a state where the recording medium P of the maximum size that can be conveyed by the image forming apparatus 10 is sandwiched between the first intermediate transfer belt 71 and the conveyor belt 20.

[ Secondary transfer rollers 47 and 48]

Each of the two secondary transfer rollers 47 and 48 is disposed inside (inner peripheral side) the conveyor belt 20. Specifically, each of the two secondary transfer rollers 47 and 48 is disposed to face a corresponding one of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 via the transfer belt 20. More specifically, the secondary transfer roller 47 nips the conveying belt 20 and the first intermediate transfer belt 71 in the contact area 71N (first secondary transfer position T21) together with the drive roller 74A of the first image forming unit 41. Further, the secondary transfer roller 48 nips the conveying belt 20 and the second intermediate transfer belt 72 in the contact area 72N (second secondary transfer position T22) together with the drive roller 74A of the second image forming unit 42.

Each of the two secondary transfer rollers 47 and 48 has a function of transferring the toner image transferred onto a corresponding one of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 to the recording medium P. In the first exemplary embodiment, the toner image on each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is secondarily transferred onto the recording medium P at each of the first secondary transfer position T21 and the second secondary transfer position T22 by applying a secondary transfer electric field between each of the secondary transfer rollers 47 and 48 and the corresponding one of the drive rollers 74A. In addition, in the first exemplary embodiment, the applied voltage applied to the secondary transfer roller 48 is, for example, a negative transfer voltage.

(fixing device 19)

The fixing device 19 illustrated in fig. 1 functions as a fixing unit that fixes the image transferred onto the recording medium. Specifically, the fixing device 19 is a device that fixes the toner image transferred onto the recording medium P to the recording medium P by means of the secondary transfer roller 48. More specifically, as shown in fig. 1, the fixing device 19 includes a heating roller 92 as a heating member and a pressing roller 94 as a pressing member. The fixing device 19 fixes the toner image formed on the recording medium P to the recording medium P by heating and pressing the recording medium P while nipping and conveying the recording medium P between the heating roller 92 and the pressing roller 94.

(arrangement of parts of image Forming apparatus 14)

The arrangement of the components of the image forming apparatus 14 will be described. Hereinafter, in particular, the arrangement of each component of the first image forming unit 41 and the arrangement of each component of the second image forming unit 42 and the second image forming unit 42 will be described.

As shown in fig. 1, specifically, the first image forming unit 41 is disposed above the accommodating unit 12 on the left side of the conveying belt 20. The second image forming unit 42 is disposed above the first image forming unit 41 on the left side of the conveyor belt 20. Specifically, the first image forming unit 41 and the second image forming unit 42 are disposed to vertically overlap each other. In other words, at least a part of the first image forming unit 41 is disposed to overlap at least a part of the second image forming unit 42 when viewed in the vertical direction.

To further describe, the second intermediate transfer belt 72 as a part of the second image forming unit 42 is disposed to vertically overlap each other above the first intermediate transfer belt 71 as a part of the first image forming unit 41.

Further, in the first exemplary embodiment, as described above, the second intermediate transfer belt 72 and the conveyor belt 20 sandwich the recording medium P in a state where the recording medium P of a standard size (for example, a4 size) is sandwiched between the first intermediate transfer belt 71 and the conveyor belt 20.

In other words, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are disposed such that a distance LA (see fig. 2) between the first secondary transfer position T21 and the second secondary transfer position T22 is shorter than the length of the standard-sized recording medium P in the conveying direction.

Further, the distance LA between the first secondary transfer position T21 and the second secondary transfer position T22 is set to be an integral multiple (n times) of the circumferential length S of the drive roller 22B of the wind-up conveying belt 20, specifically, LA is satisfied as nS ± α (0 ≦ α ≦ S/10).

A distance L1 from the first secondary transfer position T21 to the lower end of the contact surface 20A of the conveyor belt 20 is longer than a distance L5 from the second secondary transfer position T22 to the lower end of the contact surface 20A of the conveyor belt 20.

The upper end of the first image forming unit 41 overlaps the second image forming unit 42 when viewed in the horizontal direction (when viewed in the left-right direction). In other words, the upper end of the first image forming unit 41 is disposed above the lower end of the second image forming unit 42 (the former is at a higher position than the latter).

Specifically, the first image forming unit 41 includes the power supply substrate 62 at the upper end, and the upper end of the power supply substrate 62 overlaps the second image forming unit 42 when viewed in the horizontal direction. More specifically, the power supply substrate 62 includes an electronic component 62A at an upper end, and the electronic component 62A overlaps the second image forming unit 42 when viewed in the horizontal direction. In other words, the electronic component 62A of the power supply substrate 62 of the first image forming unit 41 is disposed above the lower end of the second image forming unit 42 (the former is at a higher position than the latter). Further, in fig. 2, a line extending in the left-right direction (horizontal direction) from the upper end of the first image forming unit 41 (the upper end of the electronic component 62A) is denoted by reference character H1.

The first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined in the same direction with respect to the contact surface 20A of the transfer belt 20. Specifically, as shown in fig. 5, both the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined so that the angle θ with respect to the contact surface 20A of the transfer belt 20 is an obtuse angle. More specifically, both the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined to the upper left side. More specifically, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined at the same angle.

Here, the reference of the angles of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is, for example, an angle at a contact surface 71A or 72A (lower surface) with the photosensitive drum 52.

In addition, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are disposed above the respective contact surfaces 71A and 72A, and the non-contact surfaces 71B and 72B that are not in contact with each photosensitive drum 52 are disposed along the respective contact surfaces 71A and 72A. Therefore, even when the non-contact surfaces 71B and 72B are used as references, the angles of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are understood as the same angles as the angles of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 when the contact surfaces 71A and 72A are used as references.

Further, a line 70L interconnecting the rotational axis of the driving roller 74A of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 and the rotational axis of the driven roller 74B is also provided along the respective contact surfaces 71A and 72A. Therefore, even when the line 70L is used as a reference, the angles of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are understood as the same angles as the angles of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 when the contact surfaces 71A and 72A are used as references.

The first intermediate transfer belt 71 is disposed above the lower end of the conveyor belt 20. On the other hand, the upper end of the second intermediate transfer belt 72 is disposed above the upper end of the conveyor belt 20. Specifically, the upper end of the portion of the second intermediate transfer belt 72 that is wound around the driven roller 74 is disposed above (at a position higher than) the upper end of the portion of the transfer belt 20 that is wound around the drive roller 22B. In addition, in fig. 2, a line extending in the left-right direction (horizontal direction) from the upper end of the conveyor belt 20 is denoted by reference character H2. Further, in fig. 1 and 2, an upper end of the second intermediate transfer belt 72 is denoted by 70U.

Further, as shown in fig. 1, the upper end of the second intermediate transfer belt 72 is disposed below the upper end of the fixing device 19. Specifically, the upper end of the portion of the second intermediate transfer belt 72 that is wound around the driven roller 74B is disposed below (at a position lower than) the heating roller 92 and the pressing roller 94 of the fixing device 19.

(Charge applying rollers 81 and 82)

In the first exemplary embodiment, the contact areas 71N and 72N of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are in contact with the transfer belt 20. Since each of the first intermediate transfer belt 71 and the conveyor belt 20 is a belt member, it is easily deformed, and the recording medium P having passed through the contact area 71N is easily discharged in a posture where it is wound around the first intermediate transfer belt 71. Therefore, it is necessary to reduce the possibility that the recording medium P passing therethrough is separated from the conveyor belt 20. The charge applying rollers 81 and 82 shown in fig. 2 are an embodiment of a charge applying unit that applies an electric charge that attracts the recording medium P to the conveying belt 20. The charge application rollers 81 and 82 are disposed between the first secondary transfer position T21 and the second secondary transfer position T21. Specifically, the charge application roller 81 is disposed on the lower side between the first secondary transfer position T21 and the second secondary transfer position T22. The charge application roller 82 is disposed on the upper side between the first secondary transfer position T21 and the second secondary transfer position T22.

Further, a distance L2 between the charge application roller 81 and the first secondary transfer position T21 is shorter than a distance L4 between the charge application roller 82 and the second secondary transfer position T22. In other words, it can be said that the charge application rollers 81 and 82 are closer to the first secondary transfer position T21 than the second secondary transfer position T22. Further, the distance L2 is shorter than the distance L3 between the charge application rollers 81 and 82. The distance L3 is the same as the distance L4.

For further description, the charge application rollers 81 and 82 are disposed on the inner side (inner peripheral side) of the conveyor belt 20. Specifically, the charge applying rollers 81 and 82 are provided on the opposing surface 20B (inner peripheral surface) that contacts the contact surface 20A of the conveyor belt 20. In other words, the charge application rollers 81 and 82 are in contact with the opposing surface 20B. The charge application rollers 81 and 82 are in contact with the opposite surface 20B of the conveyor belt 20, and are thereby driven to rotate by the conveyor belt 20. That is, the charge applying rollers 81 and 82 can be said to be driven rollers driven to rotate by the conveying belt 20.

Then, a voltage is applied between the charge applying rollers 81 and 82 and the secondary transfer roller 47 by means of, for example, electric power supplied from the high-voltage power supply substrate 66 of the first image forming unit 41. Accordingly, the electric charge attracting the recording medium P to the conveying belt 20 is applied to the conveying belt 20 by the electric charge applying rollers 81 and 82 between the first secondary transfer position T21 and the second secondary transfer position T22, and the recording medium P is attracted to the conveying belt 20 due to the electrostatic force of the electric charge.

Here, in the first exemplary embodiment, when the type of the recording medium P selected via the UI17 connected to the control board 64 of the first image forming unit 41 is a recording medium P having a thickness smaller than a reference thickness (for example, 0.08mm), power is supplied from the high-voltage power supply substrate 66 to the control board 64. In other words, when the conveying belt 20 conveys the recording medium P thinner than the recording medium P having the reference thickness, the conveying belt 20 is charged with electric charges that attract the recording medium P to the conveying belt 20. Further, when the conveying belt 20 conveys the recording medium having a reference thickness or more, the electric charge attracting the recording medium P to the conveying belt 20 is not applied to the conveying belt 20.

In addition, the recording medium P having the reference thickness is an embodiment of the first recording medium, and the recording medium P having a thickness smaller than the reference thickness is an embodiment of the second recording medium. Further, the recording medium P having the reference thickness may be plain paper. Further, in the first exemplary embodiment, the thickness (mm) of the recording medium is used as a reference for the thickness of the recording medium P, but, for example, the basis weight (g/m) of the recording medium P may be used²). Then, in the first exemplary embodiment, a positive polarity voltage or a negative polarity voltage is applied as a voltage applied to the charge application rollers 81 and 82 according to the type of the recording medium P.

Further, in the first exemplary embodiment, electric power is supplied from the high-voltage power supply substrate 66 of the first image forming unit 41 to the charge application rollers 81 and 82, but the present disclosure is not limited thereto. For example, the high-voltage power supply substrate 66 of the second image forming unit 42 may be used as a power supply that supplies power to the charge applying rollers 81 and 82. The high-voltage power supply substrate 66 of the first image forming unit 41 may supply power to one of the charge application rollers 81 and 82, and the high-voltage power supply substrate 66 of the second image forming unit 42 may supply power to the other of the charge application rollers 81 and 82. Further, electric power may be supplied to the charge application rollers 81 and 82 from a power supply provided in the apparatus main body 11 separately from the high-voltage power supply substrate 66 of the first image forming unit 41 and the high-voltage power supply substrate 66 of the second image forming unit 42.

Further, since the charge application rollers 81 and 82 have a function of assisting the conveying belt 20 in conveying the recording medium P, the charge application rollers 81 and 82 may be understood as components constituting a part of the conveying unit 13.

Operation according to the first exemplary embodiment

Next, an operation according to the first exemplary embodiment will be described.

According to the image forming apparatus of the first exemplary embodiment, the second intermediate transfer belt 72 and the conveyor belt 20 nip the recording medium P at the second secondary transfer position T22 in a state where the first intermediate transfer belt 71 and the conveyor belt 20 nip the recording medium P at the first secondary transfer position T21.

Here, with respect to the configuration having the first intermediate transfer belt 71 and the second intermediate transfer belt 72, in the configuration (first configuration) in which only a single intermediate transfer belt (only one of the first intermediate transfer belt 71 and the second intermediate transfer belt 72) nips the recording medium P together with the transfer belt 20, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are spaced apart from each other by a distance exceeding the length of the recording medium P in the transfer direction. Therefore, the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is increased.

On the other hand, in the first exemplary embodiment, as described above, the recording medium P sandwiched between the first intermediate transfer belt 71 and the conveyor belt 20 is sandwiched between the second intermediate transfer belt 72 and the conveyor belt 20. Therefore, the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is reduced as compared with the first configuration, and toner images can be transferred to the recording medium P at a plurality of positions. In other words, according to the configuration of the first exemplary embodiment, it can be said that the distance between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is reduced as compared with the first configuration. Further, in other words, according to the configuration of the first exemplary embodiment, it can be said that the distance between the first secondary transfer position T21 and the second secondary transfer position T22 is reduced as compared with the first configuration.

Further, in the first exemplary embodiment, the upper end of the first image forming unit 41 overlaps the second image forming unit 42 when viewed in the horizontal direction (when viewed in the left-right direction). Therefore, the distance between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is reduced as compared with a configuration (second configuration) in which the upper end of the first image forming unit 41 is disposed below the lower end of the second image forming unit 42. In other words, the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is reduced as compared with the second configuration.

Further, in the first exemplary embodiment, the upper end of the power supply substrate 62 of the first image forming unit 41 overlaps the second image forming unit 42 when viewed in the horizontal direction. Therefore, the distance 72 between the first intermediate transfer belt 71 and the second intermediate transfer belt is reduced as compared with a configuration (third configuration) in which the upper end of the power supply substrate 62 is disposed below the lower end of the second image forming unit 42. In other words, the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is reduced as compared with the third configuration.

Further, in the first exemplary embodiment, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined in the same direction with respect to the contact surface 20A of the transfer belt 20.

Here, in the configuration (fourth configuration) in which the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined in different directions with respect to the contact surface 20A of the transfer belt 20, a dead zone is liable to occur between the first intermediate transfer belt 71 and the second intermediate transfer belt 72. For example, in a configuration in which the first intermediate transfer belt 71 is inclined to the upper left side and the second intermediate transfer belt 72 is inclined to the upper right side, a dead zone is liable to occur in the right side area between the first intermediate transfer belt 71 and the second intermediate transfer belt 72. Further, for example, in a configuration in which the first intermediate transfer belt 71 is inclined to the upper right side and the second intermediate transfer belt 72 is inclined to the upper left side, a dead zone is liable to occur in the left side area between the first intermediate transfer belt 71 and the second intermediate transfer belt 72. As described above, in the fourth configuration, a dead zone is liable to occur, and the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 tends to become large.

On the other hand, in the first exemplary embodiment, since the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined in the same direction with respect to the contact surface 20A of the transfer belt 20, a dead zone is less likely to occur and the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is reduced as compared with the fourth configuration.

Further, in the first exemplary embodiment, each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is wound around a driving roller 74A facing the conveying belt 20 via the first intermediate transfer belt 71 and a driven roller 74B provided on the side of the driving roller 74A opposite to the conveying belt 20.

Therefore, the size in the height direction of each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is reduced as compared with a configuration in which each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is wound around three or more rollers. In particular, in the first exemplary embodiment, since the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are disposed obliquely, the dimensions in the height direction of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 tend to be larger than in the case where the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are disposed horizontally. Therefore, it is effective to reduce the dimension in the height direction of each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 by winding each belt around the driving roller 74A and the driven roller 74B.

Further, in the first exemplary embodiment, the electric charge applying rollers 81 and 82 apply the electric charge attracting the recording medium P to the conveying belt 20 between the first secondary transfer position T21 and the second secondary transfer position T22 to the conveying belt 20. The recording medium P is attracted to the conveying belt 20 by electrostatic force of electric charge.

Therefore, the recording medium P having passed through the first secondary transfer position T21 is prevented from being separated from the conveyor belt 20, as compared with the configuration (fifth configuration) in which the conveyor belt 20 conveys the recording medium P in a state where no electric charge is applied to the conveyor belt between the first secondary transfer position T21 and the second secondary transfer position T22.

In particular, in the first exemplary embodiment, when the conveying belt 20 conveys a recording medium P thinner than the recording medium P having the reference thickness, an electric charge attracting the recording medium P to the conveying belt 20 is applied to the conveying belt 20. Therefore, compared to the fifth configuration, the recording medium P thinner than the recording medium P having the reference thickness is prevented from being separated from the conveyor belt 20 after passing through the first secondary transfer position T21. In particular, this structure is effective because the recording medium P thinner than the recording medium P having the reference thickness is more easily peeled from the conveyor belt 20 than the recording medium P having the reference thickness.

Further, in the first exemplary embodiment, the charge application rollers 81 and 82 are provided on the opposing surface 20B (inner peripheral surface) of the conveyor belt 20 opposite to the contact surface 20A. Therefore, with respect to the recording medium P conveyed by the conveyor belt 20, the recording medium P is attracted to the conveyor belt 20 in a non-contact manner.

Further, in the first exemplary embodiment, the distance LA between the first secondary transfer position T21 and the second secondary transfer position T22 is an integral multiple (n times) of the circumferential length S of the drive roller 22B around which the conveyor belt 20 is wound.

Therefore, compared with a configuration (sixth configuration) in which the distance between the first secondary transfer position T21 and the second secondary transfer position T22 is different from the integral multiple of the circumferential length of the drive roller 22B, a change in the speed of the conveyor belt 20 due to the eccentricity of the drive roller 22B tends to occur at the first secondary transfer position T21 and the second secondary transfer position T22 at the same period. Therefore, compared to the sixth configuration, the transfer deviation between the first secondary transfer position T21 and the second secondary transfer position T22 due to the eccentricity of the drive roller 22B is prevented.

Modification of arrangement of first intermediate transfer belt 71 and second intermediate transfer belt 72

In the first exemplary embodiment, the first intermediate transfer belt 71 is disposed above the lower end of the conveyor belt 20, and the upper end of the second intermediate transfer belt 72 is disposed above the upper end of the conveyor belt 20, but the present disclosure is not limited thereto.

As shown in fig. 6, for example, the lower end of the first intermediate transfer belt 71 and the upper end of the second intermediate transfer belt 72 may be disposed within the height of the conveyor belt 20 in the up-down direction.

That is, the first intermediate transfer belt 71 may be disposed above the lower end of the conveyor belt 20, and the upper end of the second intermediate transfer belt 72 may be disposed below the upper end of the conveyor belt 20. Further, in fig. 6, a line extending in the left-right direction (horizontal direction) from the upper end of the conveyor belt 20 is denoted by reference character H2. Further, in fig. 6, the upper end of the second intermediate transfer belt 72 is denoted by 70U.

According to the present modification, the distance between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is reduced as compared with a configuration (seventh configuration) in which the lower end of the first intermediate transfer belt 71 and the upper end of the second intermediate transfer belt 72 are disposed outside the height of the conveyor belt 20 in the up-down direction. In other words, the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is reduced as compared with the seventh configuration. In addition, in the present modification, the amount by which the upper end of the first image forming unit 41 overlaps the second image forming unit 42 when viewed in the horizontal direction (when viewed in the left-right direction) is increased as compared with the configuration shown in fig. 2.

Other variants

In the first exemplary embodiment, the upper end of the first image forming unit 41 overlaps the second image forming unit 42 when viewed in the horizontal direction (when viewed in the left-right direction), but the present disclosure is not limited thereto. For example, the upper end of the first image forming unit 41 may be disposed below the lower end of the second image forming unit 42.

Further, in the first exemplary embodiment, the upper end of the power supply substrate 62 of the first image forming unit 41 overlaps the second image forming unit 42 when viewed in the horizontal direction, but the present disclosure is not limited thereto. For example, the upper end of the power supply substrate 62 may be disposed below the lower end of the second image forming unit 42.

Further, in the first exemplary embodiment, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined at the same angle with respect to the contact surface 20A of the transfer belt 20, but the present disclosure is not limited thereto. For example, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 may be inclined at different angles with respect to the contact surface 20A of the transfer belt 20.

Further, in the first exemplary embodiment, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined in the same direction with respect to the contact surface 20A of the transfer belt 20, but the present disclosure is not limited thereto. For example, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 may be configured to be inclined in different directions with respect to the contact surface 20A of the transfer belt 20. Further, at least one of the first intermediate transfer belt 71 or the second intermediate transfer belt 72 may be disposed in the horizontal direction.

Further, in the first exemplary embodiment, the electric charge applying rollers 81 and 82 are configured to apply electric charges attracting the recording medium P to the conveyor belt 20 between the first secondary transfer position T21 and the second secondary transfer position T22, but the present disclosure is not limited thereto. For example, the conveying belt 20 may convey the recording medium P in a state where no electric charge is applied to the conveying belt between the first secondary transfer position T21 and the second secondary transfer position T22.

Further, in the first exemplary embodiment, when the conveying belt 20 conveys a recording medium P thinner than the recording medium P having the reference thickness, the electric charge attracting the recording medium P to the conveying belt 20 is applied to the conveying belt 20, but the present disclosure is not limited thereto. For example, an electric charge that attracts the recording medium P to the conveyor belt 20 may be applied to the conveyor belt 20 regardless of the thickness of the recording medium P.

Further, in the first exemplary embodiment, a voltage is applied between the charge application rollers 81 and 82 and the secondary transfer roller 47, but the present disclosure is not limited thereto. For example, a voltage may be applied between the charge application roller 81 and the charge application roller 82.

Further, in the first exemplary embodiment, each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is wound around the driving roller 74A and the driven roller 74B, but the present disclosure is not limited thereto. For example, each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 may be wound around three or more rollers.

Further, in the first exemplary embodiment, the distance LA between the first secondary transfer position T21 and the second secondary transfer position T22 is an integral multiple (n times) of the circumferential length S of the drive roller 22B around which the conveyor belt 20 is wound, but the present disclosure is not limited thereto. For example, the distance between the first secondary transfer position T21 and the second secondary transfer position T22 may be different from an integral multiple of the circumference of the driving roller 22B.

Further, in the first exemplary embodiment, the recording medium P is conveyed upward by the conveying belt 20, but the present disclosure is not limited thereto. For example, the conveyor belt 20 may be configured to convey the recording medium P downward as long as the conveyor belt conveys the recording medium P in the vertical direction.

Further, in the first exemplary embodiment, the first image forming unit 41 includes toner image forming portions 50 for a total of four colors of yellow (Y), magenta (M), cyan (C), and white (W) as the four toner image forming portions 50, and the second image forming unit 42 includes toner image forming portions 50 for a total of four colors of transparent (T), silver (S), gold (G), and black (K) as the four toner image forming portions 50, but the disclosure is not limited thereto. For example, a part or all of the toner image forming portions 50 of colors included in each of the first image forming unit 41 and the second image forming unit 42 may be replaced, and toner image forming portions 50 of colors other than the above colors may be provided.

Further, in the first exemplary embodiment, each of the first image forming unit 41 and the second image forming unit 42 includes four toner image forming portions 50, but the present disclosure is not limited thereto. Each of the first image forming unit 41 and the second image forming unit 42 may include two or three toner image forming portions 50 or five or more toner image forming portions 50. That is, each of the first image forming unit 41 and the second image forming unit 42 may have a plurality of toner image forming portions 50.

Further, in the first exemplary embodiment, the image forming apparatus 14 includes two image forming units (the first image forming unit 41 and the second image forming unit 42), but the present disclosure is not limited thereto. The image forming device 14 may further include a third image forming unit, and the image forming device 14 may have three or more image forming units.

Further, in the first exemplary embodiment, the image forming apparatus 14 includes two intermediate transfer belts (the first intermediate transfer belt 71 and the second intermediate transfer belt 72), but the present disclosure is not limited thereto. The image forming device 14 may also have a third intermediate transfer belt, and the image forming device 14 may have three or more intermediate transfer belts.

The present disclosure is not limited to the first exemplary embodiment described above, and various modifications, alterations, and improvements may be made without departing from the scope of the present disclosure. For example, the above-described modifications may be appropriately combined with each other.

Image forming apparatus 110

The configuration of the image forming apparatus 110 according to the second exemplary embodiment will be described. Fig. 7 is a schematic diagram showing the configuration of an image forming apparatus 110 according to a second exemplary embodiment.

The image forming apparatus 110 shown in fig. 7 is an embodiment of an image forming apparatus that forms an image on a recording medium. Specifically, the image forming apparatus 110 is an electrophotographic image forming apparatus that forms a toner image (an example of an image) on a recording medium P. More specifically, as shown in fig. 7, the image forming apparatus 110 includes an apparatus main body 111, an accommodating unit 112, a discharging unit 118, a conveying unit 113, an image forming device 114, a fixing device 119, and charge removing rollers 181 and 182. Hereinafter, the respective units (the apparatus main body 111, the accommodating unit 112, the discharging unit 118, the conveying unit 113, the image forming device 114, the fixing device 119, and the charge removing rollers 181 and 182) of the image forming apparatus 110 will be described.

(apparatus body 111, accommodation unit 112, and discharge unit 118)

The apparatus main body 111 shown in fig. 7 has a function of accommodating each component therein. The apparatus main body 111 is configured with, for example, a box-shaped housing.

The accommodating unit 112 has a function of accommodating a recording medium P such as a sheet. As shown in fig. 7, the accommodating unit 112 is provided at a lower portion inside the apparatus main body 111. In the second exemplary embodiment, the recording media P are accommodated in the accommodating unit 112 by being stacked in the accommodating unit 112.

The discharge unit 118 has a function of discharging the recording medium P on which the toner image has been formed. As shown in fig. 7, the discharge unit 118 is provided in an upper region of the apparatus main body 111. In the second exemplary embodiment, the recording medium P discharged toward the discharge unit 118 is stacked on the discharge unit 118.

(transfer unit 113)

The conveying unit 113 shown in fig. 7 has a function of conveying the recording medium P. Specifically, the conveying unit 113 has a function of conveying the recording medium P along a vertically extending conveying path 138. More specifically, the conveying unit 113 has a function of conveying the recording medium P upward from the accommodating unit 112 to the discharge unit 118 in the conveying path 138.

To further describe, as shown in fig. 7, the conveying unit 113 includes a delivery roller 132, a plurality of conveying rollers 134, a conveying belt 120, and a discharge roller 136. The delivery roller 132 is a roller that delivers the recording medium P accommodated in the accommodating unit 112. The plurality of conveying rollers 134 are rollers that convey the recording medium P delivered by the delivery roller 132 toward the conveying belt 120.

The conveyor belt 120 is disposed along a vertically extending conveyance path 138. The conveying belt 120 has a function of conveying the recording medium P by contacting one surface of the recording medium P.

Specifically, the conveyor belt 120 is in the shape of a belt having a width in the front-rear direction, and is formed in an endless shape. More specifically, the conveyor belt 120 is formed, for example, in an endless shape without an end portion.

To further illustrate, the conveyor belt 120 is wrapped around a pair of rollers 122. Specifically, the conveyor belt 120 is wound in a state where tension is applied to a pair of rollers 122 spaced apart from each other at a certain distance in the up-down direction (vertical direction). More specifically, the conveying belt 120 is wound in a state in which tension is applied to a driven roller 122A disposed in a lower portion inside the apparatus main body 111 and a driving roller 122B disposed above the driven roller 122A as a pair of rollers 122. In the second exemplary embodiment, when the drive roller 122B is rotated in one direction (the direction of the arrow a) by a drive source (not shown), the conveyance belt 120 is circulated in one direction (the direction of the arrow B).

To further describe, the conveying belt 120 has a function of conveying the recording medium P by contacting a non-image surface of the recording medium P at an outer peripheral surface thereof. Specifically, the conveying belt 120 is in contact with the non-image surface of the recording medium P at a contact surface 120A facing the left side of the outer peripheral surface (the first intermediate transfer belt 171 and the second intermediate transfer belt 172 side to be described later) to convey the recording medium P. More specifically, the conveying belt 120 electrostatically attracts the non-image surface of the recording medium P to the contact surface 120A to convey the recording medium P. Further, specifically, the contact surface 120A is a surface linearly extending in the vertical direction. Further, the non-image surface of the recording medium P is a surface opposite to the image surface on which the toner image is formed. As described above, in the second exemplary embodiment, the conveying belt 120 is configured to convey the recording medium P from the lower side to the upper side in the direction of gravity.

The discharge roller 136 is a roller that discharges the recording medium P, which has been conveyed by the conveyor belt 120 and then passed through the fixing device 119, to the discharge unit 118.

As described above, the conveying unit 113 conveys the recording medium P upward. Therefore, in the conveying unit 113, the upward direction is regarded as the conveying direction. Further, in the conveyance unit 113, the lower side is the upstream side in the conveyance direction, and the upper side is the downstream side in the conveyance direction.

(image Forming apparatus 114)

The image forming apparatus 114 shown in fig. 7 has a function of forming a toner image (an example of an image) on a recording medium P. Specifically, as shown in fig. 7, the image forming apparatus 114 includes a first image forming unit 141, a second image forming unit 142, and two secondary transfer rollers 147 and 148.

Hereinafter, the configurations of the first image forming unit 141, the second image forming unit 142, and the two secondary transfer rollers 147 and 148 will be described.

[ first image forming unit 141]

As shown in fig. 7, the first image forming unit 141 is disposed at a lower portion inside the apparatus main body 111. Specifically, the first image forming unit 141 is disposed above the accommodating unit 112 on the left side of the conveyance belt 120.

As shown in fig. 8 and 9, the first image forming unit 141 includes a unit main body 160, four toner image forming portions 150, four primary transfer rollers 175, a first intermediate transfer belt 171, a motor 168, a power supply substrate 162, a control board 164, and a high-voltage power supply substrate 166.

Specifically, the first image forming unit 141 includes toner image forming portions 150 for a total of four colors of yellow (Y), magenta (M), cyan (C), and white (W) as four toner image forming portions 150. Reference numerals "Y", "M", "C", and "W" shown in fig. 8 denote parts corresponding to the respective colors. Further, since the toner image forming portions 150 of the respective colors are configured in the same manner except for the toner, each component of the toner image forming portion 150(Y) in fig. 8 is given the same reference numeral representing the toner image forming portion 150 of each color. Hereinafter, each component of the first image forming unit 141 (the unit main body 160, the four toner image forming portions 150, the four primary transfer rollers 175, the first intermediate transfer belt 171, the motor 168, the power supply substrate 162, the control board 164, and the high-voltage power supply substrate 166) will be described.

[ Unit body 160]

The unit main body 160 shown in fig. 9 serves as a support body that supports each component of the first image forming unit 141. The unit main body 160 is configured with a frame formed of, for example, a sheet metal. As shown in fig. 9, the unit body 160 includes, for example, an upper wall 160U, a front wall 160F, a rear wall 160R, and a left wall 160L (side walls). In addition, in fig. 8, the front wall 160F and the left wall 160L (side walls) are omitted.

[ toner image forming portion 150]

As shown in fig. 8, the toner image forming portion 150 of each color includes a photosensitive drum 152 (photoconductor) that rotates in one direction (the direction of arrow E). Further, the toner image forming portion 150 of each color includes a charging device 153, an exposure device 154, a developing device 156, and a removing device 158.

In the toner image forming portion 150 of each color, the charging device 153 charges the photosensitive drum 152. Further, the exposure device 154 exposes the photosensitive drum 152 charged by the charging device 153 to form an electrostatic latent image on the photosensitive drum 152. Further, the developing device 156 develops the electrostatic latent image formed on the photosensitive drum 152 by the exposure device 154 to form a toner image. The removing device 158 is configured with a blade that removes toner remaining on the photosensitive drum 152 after the toner image is transferred onto a first intermediate transfer belt 171, which will be described later.

[ Primary transfer roller 175]

As shown in fig. 8, four primary transfer rollers 175 are disposed inside (on the inner peripheral side) the first intermediate transfer belt 171. Specifically, each of the four primary transfer rollers 175 is disposed to face the photosensitive drum 152 of the corresponding color via the first intermediate transfer belt 171.

Each primary transfer roller 175 has a function of transferring the toner image on the photosensitive drum 152 of the corresponding color onto the first intermediate transfer belt 171 at a primary transfer position T3 between the photosensitive drum 152 and the primary transfer roller 175. In the second exemplary embodiment, the toner image formed on the photosensitive drum 152 is transferred onto the first intermediate transfer belt 171 at the primary transfer position T3 by applying a primary transfer electric field between the primary transfer roller 175 and the photosensitive drum 152. In this way, the toner images on the photosensitive drums 152 of the respective colors are primarily transferred onto the first intermediate transfer belt 171 in an overlapping manner.

[ first intermediate transfer belt 171]

The first intermediate transfer belt 171 has a function of conveying the toner image transferred from the photosensitive drum 152 of each color of the first image forming unit 141 to a first secondary transfer position T41 to be described later. Specifically, the first intermediate transfer belt 171 is configured as follows.

The first intermediate transfer belt 171 has a belt shape having a width in the front-rear direction, and is formed in an endless shape. Specifically, the first intermediate transfer belt 171 is formed, for example, in an endless shape without an end portion.

For further description, the first intermediate transfer belt 171 is wound around a pair of rollers 174. Specifically, the first intermediate transfer belt 171 is wound under tension around a pair of rollers 174 spaced apart from each other in the left-right direction by a certain distance. More specifically, the first intermediate transfer belt 171 is wound in a tensioned state around a driving roller 174A provided in a right side area (the side of the conveying belt 120) inside the apparatus main body 111 and a driven roller 174B provided on the left side of the driving roller 174A (on the opposite side of the driving roller 174A with respect to the conveying belt 120) as a pair of rollers 174. In the second exemplary embodiment, when the driving roller 174A is rotated in one direction (the direction of arrow C) by the motor 168, the first intermediate transfer belt 171 is circulated in one direction (the direction of arrow D). In addition, the driving roller 174A serves as an opposing roller (supporting roller) of the secondary transfer roller 148.

The first intermediate transfer belt 171 has a contact area 171N (nip area), and the contact area 171N is in contact with the conveyance belt 120 in a portion wound around the driving roller 174A. The contact area 171N is a first secondary transfer position T41 at which the toner image on the first intermediate transfer belt 171 is transferred onto the recording medium P at the first secondary transfer position T41. Further, the first intermediate transfer belt 171 nips and conveys the recording medium P in the contact area 171N together with the conveyance belt 120. The first secondary transfer position T41 is an example of the first transfer position.

Further, the first image forming unit 141 includes a removing unit 178, and the removing unit 178 removes toner remaining on the first intermediate transfer belt 171 after the toner image is transferred onto the recording medium P. The removing unit 178 is configured with a blade provided between the high-voltage power supply substrate 166 and the conveyor belt 120 on the upper side of the first intermediate transfer belt 171. The counter roller 179 is disposed below the removing unit 178 so as to face the removing unit 178 via the first intermediate transfer belt 171.

[ Motor 168]

As shown in fig. 9, a motor 168 is provided on the rear wall 160R of the unit main body 160 in the first image forming unit 141. The motor 168 serves as a driving source that drives the driving member of the first image forming unit 141. Specifically, the motor 168 drives, for example, the photosensitive drum 152, the developing roller 156A of the developing device 156, and the driving roller 174A wound by the first intermediate transfer belt 171 via a gear train (not shown). Further, the driving force of the motor 168 is transmitted to, for example, the delivery roller 132 and the plurality of conveyance rollers 134 of the conveyance unit 113, so that the delivery roller 132 and the plurality of conveyance rollers 134 are driven to rotate.

[ Power supply substrate 162, control board 164, and high-voltage power supply substrate 166]

As shown in fig. 8 and 9, a power supply substrate 162, a control board 164, and a high voltage power supply substrate 166 are disposed on the top of the unit body 160.

The power supply substrate 162 has a function of receiving power supplied from an external power supply (not shown) of the image forming apparatus 110 via a wire (not shown) and supplying power of a predetermined voltage to the motor 168 and the like. The power supply substrate 162 includes an electronic component 162A on its upper surface.

The control board 164 has a function of controlling the driving of each component of the first image forming unit 141. The control board 164 includes a recording unit configured with, for example: a ROM or memory in which a program is recorded; and a processor operating according to the program. The control board 164 includes electronic components 164A on an upper surface thereof.

As shown in fig. 10, a user interface 117 (hereinafter, referred to as a UI 117) as an operation unit is connected to the control board 164. The UI 117 is configured with, for example, a liquid crystal display with a touch panel. Operation buttons (virtual buttons) and information to be notified to an operator (user) are displayed on a screen of the UI.

The operator operates the operation buttons via the UI 117 to specify image forming conditions including selection of the type of the recording medium P. Further, the operation unit may be, for example, a Personal Computer (PC) connected to the image forming apparatus 110 via a network as long as the operation unit can specify the image forming conditions.

The high-voltage power supply substrate 166 has a function of receiving electric power supplied from an external power supply (not shown) of the image forming apparatus 110 via electric wires (not shown) and supplying electric power of a voltage higher than that of the power supply substrate 162 to the charging device 153, the developing device 156, the four primary transfer rollers 175, the secondary transfer rollers 147 and 148, the charge removing rollers 181 and 182, and the like. The high-voltage power supply substrate 166 includes an electronic component 66A on a lower surface thereof. In addition, the high voltage power substrate 166 may be configured to receive power supplied from the power substrate 162.

[ second image Forming Unit 142]

The second image forming unit 142 is disposed in an upper region inside the apparatus main body 111. Specifically, the second image forming unit 142 is disposed above the first image forming unit 141 on the left side of the conveyance belt 120. Further, the second image forming unit 142 is arranged to vertically overlap the first image forming unit 141.

In the second exemplary embodiment, the second image forming unit 142 is configured in the same manner as the first image forming unit 141. Specifically, the second image forming unit 142 includes a unit main body 160, four toner image forming portions 150, four primary transfer rollers 175, a second intermediate transfer belt 172, a motor 168, a power supply substrate 162, a control board 164, and a high-voltage power supply substrate 166.

The second image forming unit 142 includes toner image forming portions 150 for a total of four colors of transparent color (T), silver color (S), gold color (G), and black color (K) as four toner image forming portions 150. Reference numerals "T", "S", "G", and "K" shown in fig. 8 denote parts corresponding to the respective colors. Further, since the toner image forming portions 150 of the respective colors are configured in the same manner except for the toners used, each component of the toner image forming portion 150(T) in fig. 8 representing the toner image forming portion 150 of each color is given the same reference numeral. Hereinafter, since the toner image forming portion 150 of the second image forming unit 142 is configured in the same manner as the toner image forming portion 150 of the first image forming unit 141, the description thereof will be omitted.

Further, since each of the unit body 160, the four primary transfer rollers 175, the power supply substrate 162, the control board 164, and the high-voltage power supply substrate 166 in the second image forming unit 142 is configured in the same manner as each of the unit body 160, the four primary transfer rollers 175, the power supply substrate 162, the control board 164, and the high-voltage power supply substrate 166 in the first image forming unit 141, the description thereof will be omitted.

A motor 168 in the second image forming unit 142 drives, for example, the photosensitive drum 152, a developing roller 156A of the developing device 156, and a driving roller 174A wound around by a second intermediate transfer belt 172 via, for example, a gear train (not shown). Further, the driving force of the motor 168 is transmitted to, for example, a driving roller 122B of the conveying belt 120 and a heating roller 192 of the fixing device 119, which will be described later, so that the driving roller 122B and the heating roller 192 are driven to rotate. In addition, the same reference numerals are appropriately given to each component of the second image forming unit 142 having the same function as each component of the first image forming unit 141.

[ second intermediate transfer belt 172]

The second intermediate transfer belt 172 is configured in the same manner as the first intermediate transfer belt 171 of the first image forming unit 141. The second intermediate transfer belt 172 has a function of conveying the toner image transferred from the photosensitive drum 152 of each color of the second image forming unit 142 to the second secondary transfer position T42.

Specifically, the second intermediate transfer belt 172 includes a contact area 172N (nip area), and the contact area 172N is in contact with the transfer belt 120 in a portion wound around the driving roller 174A. The contact area 172N is a second secondary transfer position T42 at which the toner image on the second intermediate transfer belt 172 is transferred onto the recording medium P at the second secondary transfer position T42. In addition, the second secondary transfer position T42 is an example of the second transfer position.

Further, the second intermediate transfer belt 172 has a function of nipping the recording medium P in a contact area 172N together with the conveyance belt 120, the recording medium P being in a state of being nipped between the first intermediate transfer belt 171 and the conveyance belt 120. In other words, the second intermediate transfer belt 172 has a function of nipping the recording medium P together with the transfer belt 120 simultaneously with the first intermediate transfer belt 171.

For further description, the second intermediate transfer belt 172 and the first intermediate transfer belt 171 vertically overlap each other in the direction of gravity. Specifically, the second intermediate transfer belt 172 is disposed above the first intermediate transfer belt 171 so as to overlap the first intermediate transfer belt 171 in the direction of gravity.

[ Secondary transfer rollers 147 and 148]

Each of the two secondary transfer rollers 147 and 148 is disposed inside (inner peripheral side) the conveyor belt 120. Specifically, each of the two secondary transfer rollers 147 and 148 is disposed to face a corresponding one of the first intermediate transfer belt 171 and the second intermediate transfer belt 172 via the transfer belt 120. More specifically, the secondary transfer roller 147 nips the conveying belt 120 and the first intermediate transfer belt 171 in the contact area 171N (first secondary transfer position T41) together with the driving roller 174A of the first image forming unit 141. Further, the secondary transfer roller 148 nips the conveying belt 120 and the second intermediate transfer belt 172 in the contact region 172N (second secondary transfer position T42) together with the driving roller 174A of the second image forming unit 142.

Each of the two secondary transfer rollers 147 and 148 has a function of transferring the toner image transferred onto the corresponding one of the first intermediate transfer belt 171 and the second intermediate transfer belt 172 to the recording medium P. In the second exemplary embodiment, the toner image on each of the first intermediate transfer belt 171 and the second intermediate transfer belt 172 is secondarily transferred onto the recording medium P at each of the first secondary transfer position T41 and the second secondary transfer position T42 by applying a secondary transfer electric field between each of the secondary transfer rollers 147 and 148 and the corresponding one of the driving rollers 174A. In addition, in the second exemplary embodiment, the applied voltage applied to the secondary transfer roller 148 is, for example, a negative transfer voltage.

(fixing device 119)

A fixing device 119 shown in fig. 7 functions as a fixing unit that fixes the image transferred onto the recording medium. Specifically, the fixing device 119 is a device that fixes the toner image transferred onto the recording medium P to the recording medium P by means of the secondary transfer roller 148. More specifically, as shown in fig. 7, the fixing device 119 includes a heating roller 192 as a heating member and a pressure roller 194 as a pressure member. The fixing device 119 fixes the toner image formed on the recording medium P to the recording medium P by heating and pressing the recording medium P while nipping and conveying the recording medium P between the heating roller 192 and the pressing roller 194.

(Charge removing rollers 181 and 182)

The charge removing rollers 181 and 182 illustrated in fig. 8 are an embodiment of a charge removing unit that removes the charge of the recording medium P charged at the first secondary transfer position T41. The charge removing rollers 181 and 182 are disposed between the first secondary transfer position T41 and the second secondary transfer position T42. Specifically, the charge removing roller 181 is disposed on the lower side between the first secondary transfer position T41 and the second secondary transfer position T42. The charge removing roller 182 is disposed on the upper side between the first secondary transfer position T41 and the second secondary transfer position T42.

Further, a distance L6 between the charge removing roller 181 and the first secondary transfer position T41 is shorter than a distance L7 between the charge removing roller 182 and the second secondary transfer position T42. In other words, it can be said that the charge removing rollers 181 and 182 are closer to the first secondary transfer position T41 than the second secondary transfer position T42. Further, the distance L6 is shorter than the distance L8 between the charge removing rollers 181 and 182. The distance L7 is the same as the distance L8.

For further description, the charge removing rollers 181 and 182 are disposed on the inner side (inner peripheral side) of the conveying belt 120. Specifically, the charge removing rollers 181 and 182 are provided on the opposite surface 120B (an example of an inner peripheral surface) of the contact surface 120A of the conveying belt 120. In other words, the charge removing rollers 181 and 182 are in contact with the opposing surface 120B.

The charge removing rollers 181 and 182 are in contact with the opposite surface 120B of the conveying belt 120, thereby being driven to rotate by the conveying belt 120. That is, the charge removing rollers 181 and 182 are driven rollers that are driven to rotate by the conveying belt 120.

Then, a voltage is applied between the charge removing rollers 181 and 182 and the secondary transfer roller 147 by means of, for example, electric power supplied from the high-voltage power supply substrate 166 of the first image forming unit 141. As described above, the charge removing rollers 181 and 182 are configured to remove the charge of the recording medium P by applying the charge having the polarity opposite to that of the recording medium P charged at the first secondary transfer position T41 when the voltage is applied to the charge removing rollers 181 and 182.

As described above, since the charge removing rollers 181 and 182 are in contact with the opposed surface 120B of the conveying belt 120, in the second exemplary embodiment, the charge of the recording medium P is removed via the conveying belt 120 by the charge removing rollers 181 and 182.

In addition, "charge removal" means to remove (neutralize) at least a part of the charge of the charged recording medium P, and is not limited to completely removing the charge. That is, the amount of charge sufficient for the recording medium P is reduced, thereby reducing the electrostatic force. Then, in the second exemplary embodiment, a positive polarity voltage or a negative polarity voltage is applied as a voltage applied to the charge removing rollers 181 and 182 according to the type of the recording medium P.

(drive control of the Charge removing rollers 181 and 182)

In the second exemplary embodiment, the control board 164, which is an example of a receiving unit that receives information about the recording medium P, changes the voltage applied to the charge removing rollers 181 and 182 based on the received information about the recording medium P. Specifically, for example, the control board 164 of the first image forming unit 141 receives the type information on the recording medium P, and the control board 164 drives and controls the high-voltage power supply substrate 166 based on the type information on the recording medium P, and changes the voltage applied to the charge removing rollers 181 and 182 (see fig. 10).

The type information on the recording medium P is an example of information on the recording medium P, and is information indicating the type of the recording medium P. The type information about the recording medium P, for example, the type of the recording medium P selected via the UI 117, is received by the control board 164 of the first image forming unit 141. In addition, the type information on the recording medium P may be received from an external device connected to the image forming apparatus 110. Further, for example, the type of the recording medium P may be detected by a sensor, and the result may be received as type information on the recording medium P.

Then, for example, when the received type information indicates that the type of the recording medium P is a first type, the control board 164 applies a first voltage to the charge removing rollers 181 and 182, and when the received type information indicates that the type of the recording medium P is a second type having a higher resistance than the first type, the control board 164 applies a second voltage higher than the first voltage to the charge removing rollers 181 and 182. Accordingly, the charge amount of the charge removing rollers 181 and 182 is increased to improve the charge removing capability thereof.

In other words, for example, when the received type information indicates that the type of the recording medium P is a high-resistance type having a high resistance, the control board 164 increases the voltage applied to the charge removing rollers 181 and 182.

In addition, in the second exemplary embodiment, electric power is supplied from the high voltage power supply substrate 166 of the first image forming unit 141 to the charge removing rollers 181 and 182, but the present disclosure is not limited thereto. For example, the high-voltage power supply substrate 166 of the second image forming unit 142 may be used as a power supply that supplies power to the charge removing rollers 181 and 182. The high-voltage power supply substrate 166 of the first image forming unit 141 may supply power to one of the charge removing rollers 181 and 182, and the high-voltage power supply substrate 166 of the second image forming unit 142 may supply power to the other of the charge removing rollers 181 and 182. Further, electric power may be supplied to the charge removing rollers 181 and 182 from a power supply provided in the apparatus main body 111 separately from the high-voltage power supply substrate 166 of the first image forming unit 141 and the high-voltage power supply substrate 166 of the second image forming unit 142.

Operation according to the second exemplary embodiment

Next, an operation according to the second exemplary embodiment will be described.

In the second exemplary embodiment, the toner image is transferred from the first intermediate transfer belt 171 to the recording medium P conveyed upward by the conveying belt 120 at the first secondary transfer position T41 by applying a secondary transfer electric field between the secondary transfer roller 147 of the first intermediate transfer belt 171 and the driving roller 174A. At this time, the recording medium P is charged.

The recording medium P charged at the first secondary transfer position T41 is further conveyed upward by the conveyor belt 120, and the electric charge of the recording medium is removed by the electric charge removing rollers 181 and 182 between the first secondary transfer position T41 and the second secondary transfer position T42. The recording medium P from which the electric charges have been removed by the electric charge removing rollers 181 and 182 is further conveyed upward by the conveying belt 120, and the toner image is transferred from the secondary intermediate transfer belt 172 to the recording medium at the second secondary transfer position T42 by applying a secondary transfer electric field between the secondary transfer roller 148 of the secondary intermediate transfer belt 172 and the driving roller 174A.

As described above, in the second exemplary embodiment, since the electric charges of the recording medium P are removed by the electric charge removing rollers 181 and 182, the influence on the transferability of the toner image at the second secondary transfer position T42 is prevented, as compared with the configuration in which the recording medium P is conveyed to the second secondary transfer position T42 in the charged state at the first secondary transfer position T41.

Further, in the second exemplary embodiment, the charge removing rollers 181 and 182 are provided inside the conveying belt 120, and remove the charge of the recording medium P via the conveying belt 120. Accordingly, for the recording medium P conveyed by the conveying belt 120, the charge removing rollers 181 and 182 remove the charge of the recording medium P in a non-contact manner. As described above, since the charge removing rollers 181 and 182 do not contact the recording medium P, deviation of the recording medium P from the conveyor belt 120 or wrinkles of the recording medium P are further prevented, compared to the configuration in which the charge removing rollers 181 and 182 contact the recording medium.

Further, in the second exemplary embodiment, the charge removing rollers 181 and 182 are driven rollers that are in contact with the opposing surface 120B of the conveying belt 120 and are driven to rotate by the conveying belt 120. Therefore, the frictional resistance with the conveyor belt 120 is reduced as compared with the configuration in which the charge removing rollers 181 and 182 slide with respect to the conveyor belt 120. Further, "slide" refers to a state of moving in a sliding motion.

Further, in the second exemplary embodiment, the conveying belt 120 conveys the recording medium P upward, and the second intermediate transfer belt 172 and the first intermediate transfer belt 171 vertically overlap in the direction of gravity. Therefore, compared to a configuration in which the recording medium P is conveyed by the conveying belt 120 in the horizontal direction and the entire first intermediate transfer belt 171 is arranged offset in the horizontal direction with respect to the second intermediate transfer belt 172, the size in the horizontal direction of the image forming apparatus 110 is reduced, and the influence on the transferability of the toner image at the second secondary transfer position T42 is prevented.

Further, in the second exemplary embodiment, the charge removing rollers 181 and 182 are configured to remove the electric charge of the recording medium P by applying an electric charge having a polarity opposite to that of the recording medium P charged at the first secondary transfer position T41 when a voltage is applied to the charge removing rollers 181 and 182. Therefore, the charge removing ability of the charge removing rollers 181 and 182 is improved as compared with a configuration in which the charge removing rollers 181 and 182 are grounded to a reference potential (ground) and function as a ground that simply discharges the charge of the recording medium P.

Further, in the second exemplary embodiment, the control board 164 drives and controls the high-voltage power supply substrate 166 based on the type information about the recording medium P to change the voltage applied to the charge removing rollers 181 and 182. Therefore, compared to the configuration in which a constant voltage is applied to the charge removing rollers 181 and 182, the charge removing ability of the charge removing rollers 181 and 182 varies according to the recording medium P.

Modification examples

In the second exemplary embodiment, the charge removing rollers 181 and 182 are disposed on the inner side (inner peripheral side) of the conveying belt 120, but the present disclosure is not limited thereto. For example, the charge removing rollers 181 and 182 may be disposed in a space between the first image forming unit 141 and the second image forming unit 142 outside the conveyance belt 120. In this configuration, a charge removing unit other than the charge removing rollers 181 and 182 is provided on the contact surface 120A side of the conveying belt 120, for example, between the first secondary transfer position T41 and the second secondary transfer position T42. In this case, it is necessary to remove the charge of the recording medium P without disturbing the toner image transferred from the first image forming unit 141. Therefore, specifically, the charge removing unit is disposed to face the contact surface 120A in the non-contact direction, and it is necessary to form an electrical path from the end of the conveyor belt 120 intersecting the traveling direction of the conveyor belt 120 to the inner surface of the conveyor belt, thereby forming a path for removing the charge on the inner surface of the conveyor belt 120.

Further, in the second exemplary embodiment, the charge removing rollers 181 and 182 are driven rollers that are in contact with the opposing surface 120B of the conveying belt 120 and are driven to rotate by the conveying belt 120, but the present disclosure is not limited thereto. The charge removing rollers 181 and 182 may be configured to slide with respect to, for example, the endless conveying belt 120. Examples of the charge removing unit in this configuration refer to a charge removing pin (Detack saw), a charge removing film, and the like.

Further, in the second exemplary embodiment, a voltage is applied between the charge removing rollers 181 and 182 and the secondary transfer roller 147, but the present disclosure is not limited thereto. For example, a voltage may be applied between the charge removing roller 181 and the charge removing roller 182.

Further, in the second exemplary embodiment, the recording medium P is conveyed upward by the conveying belt 120, but the present disclosure is not limited thereto. For example, the conveying belt 120 may be configured to convey the recording medium P downward. Further, the conveyor belt 120 may be configured to convey the recording medium P in a horizontal direction.

Further, in the second exemplary embodiment, the control board 164 changes the voltage applied to the charge removing rollers 181 and 182 based on the type information on the recording medium P, but the present disclosure is not limited thereto. For example, a constant voltage may be applied to the charge removing rollers 181 and 182.

Further, in the second exemplary embodiment, a voltage is applied to the charge removing rollers 181 and 182, but the present disclosure is not limited thereto. For example, the charge removing rollers 181 and 182 may be grounded to a reference potential (ground) and may serve as a ground that discharges the charge of the charged recording medium P, and the charge removing unit may need to remove at least a part of the charge of the charged recording medium P.

Further, in the second exemplary embodiment, the first image forming unit 141 includes toner image forming portions 150 for a total of four colors of yellow (Y), magenta (M), cyan (C), and white (W) as four toner image forming portions 150, and the second image forming unit 142 includes toner image forming portions 150 for a total of four colors of transparent (T), silver (S), gold (G), and black (K) as four toner image forming portions 150, but the disclosure is not limited thereto. For example, a part or all of the toner image forming portions 150 of colors included in each of the first image forming unit 141 and the second image forming unit 142 may be replaced, and toner image forming portions 150 of colors other than the above colors may be provided.

Further, in the second exemplary embodiment, each of the first image forming unit 141 and the second image forming unit 142 includes four toner image forming portions 150, but the present disclosure is not limited thereto. Each of the first image forming unit 141 and the second image forming unit 142 may include two or three toner image forming portions 150 or five or more toner image forming portions 150. That is, each of the first image forming unit 141 and the second image forming unit 142 may have a plurality of toner image forming portions 150.

Further, in the second exemplary embodiment, the image forming apparatus 114 includes two image forming units (the first image forming unit 141 and the second image forming unit 142), but the present disclosure is not limited thereto. The image forming apparatus 114 may further include a third image forming unit, and the image forming apparatus 114 may have three or more image forming units.

The present disclosure is not limited to the above-described second exemplary embodiment, and various modifications, and improvements may be made without departing from the scope of the present disclosure. For example, the above-described modifications may be appropriately combined with each other.

The foregoing description of the exemplary embodiments of the present disclosure has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the disclosure and its practical application, to thereby enable others skilled in the art to understand the disclosure for various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the disclosure be defined by the following claims and their equivalents.