阅读说明：本技术 辊以及图像形成装置 (Roller and image forming apparatus ) 是由 荻岛和也 于 2019-09-02 设计创作，主要内容包括：本发明提供辊以及图像形成装置。辊具有：导电性的轴；弹性层,其设置于所述轴；以及非导电性的环状单元,其以与所述弹性层的端面接触的状态安装于所述轴的从所述弹性层的轴向上的两端面突出的两端部中的至少一方,在所述环状单元的与所述弹性层的端面接触的部分处设置有突出部,该突出部以比该接触的部分的厚度薄的厚度突出,并陷入到该弹性层的端面中。(The invention provides a roller and an image forming apparatus. The roller has: a conductive shaft; an elastic layer disposed on the shaft; and a non-conductive annular unit attached to at least one of both end surfaces of the shaft protruding from both end surfaces of the elastic layer in the axial direction thereof in a state of being in contact with the end surface of the elastic layer, wherein a protruding portion protruding with a thickness smaller than that of the portion in contact with the end surface of the elastic layer and recessed into the end surface of the elastic layer is provided at a portion of the annular unit in contact with the end surface of the elastic layer.)

1. A roller, having:

a conductive shaft;

an elastic layer disposed on the shaft; and

a non-conductive annular unit attached to at least one of both end portions of the shaft protruding from both end surfaces of the elastic layer in the axial direction in a state of being in contact with the end surface of the elastic layer,

a projection is provided at a portion of the ring-shaped unit that is in contact with an end face of the elastic layer, the projection projecting with a thickness thinner than that of the portion in contact and being sunk into the end face of the elastic layer.

2. The roller according to claim 1,

the protruding portion is configured as a protruding portion having a continuous annular shape.

3. The roller according to claim 1 or 2,

the protruding portion is provided at a position not in contact with the shaft.

4. The roller according to claim 3,

the surface of the protruding portion on the side opposite to the shaft is formed of an inclined surface gradually distant from the shaft in the protruding direction.

5. The roller according to any one of claims 1 to 4,

the thickness of the protruding portion is 1/2 or less of the thickness of the portion of the annular unit that contacts.

6. The roller according to any one of claims 1 to 5,

the portions of both end portions of the shaft to which the ring units are attached are two-stage stepped portions composed of a small diameter portion and a large diameter portion,

the ring unit has a two-stage shape having a small diameter portion and a large diameter portion, the small diameter portion and the large diameter portion of the ring unit being attached to the stepped portion of the shaft,

the protruding portion is provided at a large diameter portion of the annular unit that contacts an end surface of the elastic layer.

7. An image forming apparatus includes:

a roller having a conductive shaft, an elastic layer provided on the shaft, and a non-conductive annular unit attached to at least one of both end portions of the shaft protruding from both end surfaces in an axial direction of the elastic layer; and

a power supply unit supplying a voltage to a shaft of the roller,

the roller is constituted by the roller according to any one of claims 1 to 6.

Technical Field

The present disclosure relates to a roller and an image forming apparatus.

Background

Conventionally, as a technique relating to a roller member or the like in which a leakage is less likely to occur even when a high voltage is applied, a technique described in japanese patent application laid-open No. 2017-9985 is known.

Jp 2017 a-9985 describes a roller member and an image forming apparatus, wherein the roller member has an elastic layer formed on an outer peripheral surface of a core mold having a protrusion formed to protrude from a range in which the elastic layer is formed toward an axial end portion, and a non-conductive member formed of a non-conductive material and provided to the protrusion so as to sink into an end surface of the elastic layer at the axial end portion, and the roller member is used as a transfer roller or a transfer counter roller.

Disclosure of Invention

The present disclosure provides a roller and an image forming apparatus using the roller, the roller is formed by arranging at least an elastic layer on a conductive shaft capable of supplying a voltage capable of generating a discharge, the roller is provided with a non-conductive annular unit, the annular unit is arranged on an end part of the shaft protruding from an axial end part of the elastic layer in a state of contacting with an end surface of the elastic layer, compared with a case that a protruding part sinking into the end surface of the elastic layer is not arranged on a part of the annular unit contacting with the end surface of the elastic layer, the roller can inhibit the discharge generated through a gap generated between the annular unit and the elastic layer due to aging and the like.

According to a first aspect of the present disclosure, there is provided a roller having: a conductive shaft; an elastic layer disposed on the shaft; and a non-conductive annular unit attached to at least one of both end surfaces of the shaft protruding from both end surfaces of the elastic layer in the axial direction thereof in a state of being in contact with the end surface of the elastic layer, wherein a protruding portion protruding with a thickness smaller than that of the portion in contact with the end surface of the elastic layer and recessed into the end surface of the elastic layer is provided at a portion of the annular unit in contact with the end surface of the elastic layer.

According to a second aspect of the present disclosure, the protruding portion is configured as a protruding portion having an annular continuous shape.

According to a third aspect of the present disclosure, the protruding portion is provided at a position not in contact with the shaft.

According to a fourth aspect of the present disclosure, a surface of the protruding portion on a side opposite to the shaft is constituted by an inclined surface gradually distant from the shaft in a protruding direction.

According to the fifth aspect of the present disclosure, the thickness of the protruding portion is a thickness of 1/2 or less of the thickness of the contacted portion in the ring-shaped member.

According to a sixth aspect of the present disclosure, a portion of both end portions of the shaft to which the ring unit is attached is a two-stage stepped portion composed of a small diameter portion and a large diameter portion, the ring unit is a two-stage shaped unit having the small diameter portion and the large diameter portion, the small diameter portion and the large diameter portion of the ring unit are attached to the small diameter portion and the large diameter portion of the stepped portion of the shaft, respectively, and the protruding portion is provided at the large diameter portion of the ring unit that is in contact with an end face of the elastic layer.

According to a seventh aspect of the present disclosure, there is provided an image forming apparatus having: a roller having a conductive shaft, an elastic layer provided on the shaft, and a non-conductive annular unit attached to at least one of both end portions of the shaft protruding from both end surfaces in an axial direction of the elastic layer; and a power supply unit that supplies a voltage to a shaft of the roller, the roller being constituted by the roller according to any one of the aspects 1 to 6.

(Effect)

According to the roller of the first aspect, as compared with the case where the protruding portion that sinks into the end face of the elastic layer is not provided in the portion of the annular unit that contacts the end face of the elastic layer, it is possible to suppress the occurrence of discharge due to aging or the like via the gap that is generated between the annular unit and the elastic layer.

According to the roller of the second aspect, the generation of the discharge can be stably suppressed as compared with the case where the protruding portion is not formed in a continuous annular shape.

According to the roller of the third aspect, compared to the case where the protruding portion is provided at the position in contact with the shaft, the elastic layer can be prevented from being peeled off from the shaft due to the sinking of the protruding portion, and the generation of the discharge can be reliably suppressed.

According to the roller of the fourth aspect, even if the elastic layer is deformed by the projection being sunk, the generation of the discharge can be reliably suppressed, as compared with the case where the surface of the projection facing the shaft is a surface parallel to the shaft or a slope close to the shaft.

According to the roller of the fifth aspect, the amount of deformation of the elastic layer due to the depression of the projecting portion can be reduced as compared to the case where the thickness of the projecting portion is thicker than 1/2, which is the thickness of the portion of the annular member in contact with the elastic layer.

According to the roller of the sixth aspect, even if the roller is a two-stage annular unit, the generation of the discharge can be stably suppressed.

According to the image forming apparatus of the seventh aspect, as compared to the case where the protruding portion that sinks into the end face of the elastic layer is not provided in the portion of the annular unit of the roller that contacts the end face of the elastic layer, it is possible to suppress the occurrence of discharge due to aging or the like via the gap that is generated between the annular unit of the roller and the elastic layer, and also to suppress the occurrence of secondary failure due to the discharge.

Drawings

Fig. 1 is a schematic diagram showing a configuration of an image forming apparatus according to embodiment 1.

Fig. 2 is a schematic diagram showing a part of the image forming apparatus (mainly, an image forming apparatus) of fig. 1.

Fig. 3 is a schematic diagram showing another part (mainly, a part of secondary transfer) of the image forming apparatus of fig. 1.

Fig. 4 (a) is a schematic view showing the entire secondary transfer roller to which the roller of embodiment 1 is applied, and (B) is a schematic view showing one end of the roller of (a) in an enlarged manner.

Fig. 5 (a) is a schematic view showing a state where the holder and the like at one end of the secondary transfer roller in fig. 4 are removed, and (B) is a perspective view showing one end of the roller in (a).

Fig. 6 (a) is a perspective view showing one end portion of the shaft in the secondary transfer roller of fig. 5, and (B) is a perspective view showing the ring-like member in the secondary transfer roller of fig. 5.

Fig. 7 (a) and (B) are schematic diagrams showing respective states when the ring member of fig. 6 (B) is viewed from different directions.

Fig. 8 (a) is a schematic view showing one end of the shaft in the secondary transfer roller of fig. 5, and (B) is a schematic cross-sectional view taken along the line Q-Q of the annular member of fig. 7 (B).

Fig. 9 (a) is a partially sectional view showing a state where the annular member is attached to one end of the secondary transfer roller of fig. 5, and (B) is a longitudinal sectional view showing one end of the secondary transfer roller of fig. 5.

Fig. 10 is a cross-sectional view of the secondary transfer roller of embodiment 2, as a representative example.

Fig. 11 (a) is a schematic view showing one end of the shaft in the secondary transfer roller of fig. 10, and (B) is a schematic cross-sectional view showing the ring-like member in the secondary transfer roller of fig. 10.

Fig. 12 (a) is a conceptual sectional view showing an enlarged state of a portion of the annular member of embodiment 1 recessed in the elastic layer, and (B) is a conceptual sectional view showing an enlarged state of a portion of the annular member of embodiment 2 recessed in the elastic layer.

Fig. 13 is a schematic cross-sectional view showing the structure of the annular member and the state when discharge occurs in the secondary transfer roller of comparative example 1.

Fig. 14 is a conceptual sectional view showing an exaggerated state of portions of two types of protrusions as comparative reference examples of the protrusions in the annular member, which are respectively sunk into the elastic layer.

Fig. 15 is a schematic cross-sectional view showing the structure of the annular member and the state when discharge occurs in the secondary transfer roller of comparative example 2.

Detailed Description

Hereinafter, a mode for carrying out the present disclosure will be described with reference to the drawings.

[ embodiment 1]

Fig. 1 shows an image forming apparatus 1 according to embodiment 1. Arrows shown by reference numeral X, Y, Z in other drawings including fig. 1 indicate directions of width, height, and depth assumed in the drawings. In fig. 1, 2, and the like, the circular mark at the portion where the arrow of reference numeral X, Y intersects indicates that the direction of reference numeral Z is directed vertically downward on the drawing sheet.

< image Forming apparatus >

The image forming apparatus 1 is an apparatus that forms an image made of toner as a developer on a sheet 9 as an example of a recording medium by using an image forming method such as an electrophotographic method. The image forming apparatus 1 is configured as a printer that forms an image corresponding to image information input from an external device such as an information terminal or an image reading apparatus, for example.

As shown in fig. 1, the image forming apparatus 1 includes, in an internal space of a casing 10 as an example of an apparatus main body, the following units: an image forming unit 2 that forms a toner image as an unfixed image; an intermediate transfer unit 3 that temporarily holds the toner image formed by the image forming unit 2 and secondarily transfers the toner image onto a sheet of paper 9 after conveyance; a paper feed unit 4 that stores a sheet of paper 9 to be fed to a position where the intermediate transfer unit 3 performs secondary transfer, and feeds out the sheet of paper 9; and a fixing unit 5 that fixes the toner image secondarily transferred by the intermediate transfer unit 3 on the sheet 9.

The casing 10 is a structure assembled into a desired structure and shape from various materials such as support members and exterior parts. The housing 10 has a discharge storage portion 12 formed in a part of an upper surface thereof, and the discharge storage portion 12 stores the sheets 9 discharged after the image is formed in a stacked state. The chain line in fig. 1 indicates a main conveyance path when the paper 9 is conveyed inside the casing 10.

The image forming unit 2 is constituted by, for example, 4 image forming apparatuses 2Y, 2M, 2C, and 2K, and the 4 image forming apparatuses 2Y, 2M, 2C, and 2K are dedicated to forming toner images of 4 colors of yellow (Y), magenta (M), cyan (C), and black (K), respectively. The 4 image forming apparatuses 2(Y, M, C, K) of embodiment 1 are arranged in an inclined state with the left lower and the right higher inside the casing 10 shown in fig. 1.

As shown in fig. 1 or 2, each of the 4 image forming apparatuses 2(Y, M, C, K) includes a photosensitive drum 21, and the photosensitive drum 21 is an example of an image holding unit that rotates in the direction indicated by an arrow.

Further, the following devices and the like are arranged around the photosensitive drum 21 of the image forming apparatus 2(Y, M, C, K): a charging device 22 that charges an image holding area of the photosensitive drum 21; an exposure device 23, which is an example of an exposure unit, that forms an electrostatic latent image by exposing the charged image holding area of the photosensitive drum 21 in accordance with image information; developing devices 24Y, 24M, 24C, and 24K that develop the electrostatic latent image formed on the image forming surface of the photosensitive drum 21 with toner of the corresponding color to form a toner image; and a 1 st cleaning device 26 for cleaning the image forming surface of the photosensitive drum 21.

In fig. 1, for convenience, all reference numerals 21 to 24 and 26 are described in the image forming device 2K of black (K), and only a part of the image forming devices 2Y, 2M and 2C of the other colors are described, and the description of the remaining part is omitted.

The charging device 22 employs a contact charging type charging device that uses a charging roller 221 as an example of a contact charging member, and charges the charging roller 221 by supplying a necessary charging voltage from the power supply device 15. Reference numeral 223 in fig. 2 denotes a cleaning roller which cleans the surface of the roller by contacting the charging roller 221.

The developing device 24(Y, M, C, K) has substantially the same configuration except that the toner color in the developer stored in the main body (casing) 241 is different from one of the 4 colors (Y, M, C, K). That is, as shown in fig. 2, the developing device 24(Y, M, C, K) is configured such that the following components are disposed in the main body 241 thereof: a developing roller 242 that holds the developer and rotationally conveys the developer so that the developer passes through a developing process region facing the photosensitive drum 21; an agitating member 243 such as an auger that rotationally conveys the developer in the main body 241 to supply the developer to the developing roller 242 while agitating the developer; and a layer thickness regulating member 244 that regulates the amount (thickness) of the developer held by the developing roller 242. The developing roller 242 is supplied with a required developing voltage from the power supply device 15 and performs development.

The intermediate transfer unit 3 is disposed inside the casing 10 on the upper side of the image forming apparatus 2(Y, M, C, K) as the image forming unit 2.

The intermediate transfer unit 3 is configured by arranging, for example, the following: an intermediate transfer belt 31 that receives and holds the toner images formed by the image forming apparatuses 2(Y, M, C, K), respectively, in primary transfer, and then rotates to convey the toner images to a position where the paper 9 is secondarily transferred; a primary transfer device 33 that primarily transfers the toner images formed on the photosensitive drums 21 of the image forming apparatus 2(Y, M, C, K) to an image holding area on the outer peripheral surface of the intermediate transfer belt 31; a secondary transfer device 35 that secondarily transfers the toner image on the intermediate transfer belt 31 to the sheet 9; and a 2 nd cleaning device 36 that cleans the outer peripheral surface of the intermediate transfer belt 31.

The intermediate transfer belt 31 is rotated in the direction indicated by the arrow while passing through the photosensitive drums 21 of the image forming apparatus 2(Y, M, C, K), the secondary transfer device 35, and the like in order while being stretched over the plurality of support rollers 32a to 32 d. The support roller 32a is configured as a drive roller, and the support roller 32b is configured as a secondary transfer opposing roller.

As shown in fig. 1 and 2, the primary transfer device 33 employs a contact transfer type transfer device that uses a primary transfer roller 331 as an example of a contact transfer member, and performs primary transfer by supplying a required primary transfer voltage from the power supply device 15 to the primary transfer roller 331.

As shown in fig. 1 and 3, the secondary transfer device 35 employs a contact transfer type transfer device that uses a secondary transfer roller 351, which is an example of a contact transfer member, and performs secondary transfer by supplying a necessary secondary transfer voltage from the power supply device 15 to the secondary transfer roller 351.

The paper feed unit 4 is configured by arranging devices such as a paper storage 41 and a feeding device 43, wherein the paper storage 41 stores the paper 9, and the feeding device 43 feeds the paper 9 from the paper storage 41 one by one. The sheet 9 fed from the sheet feeding unit 4 is conveyed to a secondary transfer position between the intermediate transfer belt 31 of the intermediate transfer unit 3 and the secondary transfer device 35 via a sheet feeding conveyance path constituted by a sheet conveying roller 45 and a conveying guide not shown.

The fixing unit 5 is disposed above the secondary transfer position of the intermediate transfer unit 3. The fixing unit 5 is configured by disposing devices such as a rotating body 51 for heating and a rotating body 52 for pressurizing in the inner space of the casing 50. The sheet 9 fed out from the fixing unit 5 after fixing is discharged to the discharge housing section 12 via a discharge path constituted by a sheet conveying roller 47, a conveying guide not shown, and the like.

< Secondary transfer roller >

The secondary transfer roller 351 is configured as an example of the roller 6 of the present disclosure.

As shown in fig. 3 to 5, the secondary transfer roller 351 is configured to have a structure including a shaft 61, an elastic layer 62 and a surface layer 63 provided on the shaft 61, and an annular member 64 as an example of an annular means, wherein the annular member 64 is attached to both end portions 61a and 61b of the shaft 61 protruding from both end surfaces 62e of the elastic layer 62 in the axial direction D in a state of being in contact with the end surface 62e of the elastic layer 62.

In fig. 4, reference numeral 65 denotes a nonconductive holder used when the entire secondary transfer roller 351 is mounted on a mounting portion such as a support frame, not shown, while holding both end portions 61a and 61b of the shaft 61. Further, reference numeral 66 denotes a secondary gear composed of a gear for receiving the rotational power transmitted from the not-shown rotational driving device to the secondary transfer roller 351 and a relay gear for transmitting the rotational power to a rotating member other than the secondary transfer roller 351 in a relay manner, and 67 denotes a nonconductive cover for covering a gap between the holder 65 and an annular member (64) described later to hide the gap.

Bearings for rotatably supporting both end portions 61a and 61b of the shaft 61 are disposed in the two holders 65, and a power supply member, not shown, which is in contact with the shaft 61 and supplies a secondary transfer voltage from the power supply device 15 is disposed on the holder 65 on the side where the cover 67 is located. When the secondary transfer roller 351 is attached, the power supply member is in a state of being in contact with and connected to the power transmission member from the power supply device 15.

The shaft 61 is a substantially cylindrical member having a desired diameter and length as a whole, and is made of a conductive material such as stainless steel (SUS).

As shown in fig. 6 (a) and the like, the shaft 61 of embodiment 1 has both end portions 61a, 61b in which the annular member 64 is attached, and is formed as a stepped portion including a large diameter portion 612 and a small diameter portion 613 having different outer diameters. The large diameter portion 612 has the same diameter as the portion where the elastic layer 62 is provided. The small diameter portion 613 is a portion having a smaller outer diameter than the large diameter portion 612. The elastic layer 62 and the surface layer 63 are omitted in fig. 6 (a).

As shown in fig. 5, 6 (a), and the like, the shaft 61 further includes a 2 nd small diameter portion 614 and a 3 rd small diameter portion 615, which are formed to have two-step smaller outer diameters, at positions outside the small diameter portion 613. The 2 nd and 3 rd small diameter portions 614 and 615 are used for mounting of the retainer 65 and mounting of the bearing.

In the secondary transfer, the shaft 61 is supplied with a secondary transfer voltage of 5kV to 7kV via a power supply member, not shown, located in the holder 65.

The elastic layer 62 is an elastically deformable layer having a desired layer thickness, and is formed using a material such as a conductive foam material (conductive foam ECO/NBR).