阅读说明：本技术 用以管理工艺辊和光电导鼓之间的位置关系的构件
(Member for managing positional relationship between process roller and photoconductive drum
) 是由 文智园
文镕一
安勇南
赵镛官 于 2018-07-04 设计创作，主要内容包括：一种电子照相图像形成设备包括：光电导鼓；工艺辊,用以在所述工艺辊弹性接触所述光电导鼓的表面的状态下旋转；和连接构件,用以允许所述工艺辊跟随所述光电导鼓在所述光电导鼓的轴向方向上的移动。(An electrophotographic image forming apparatus includes: a photoconductive drum; a process roller to rotate in a state where the process roller elastically contacts a surface of the photoconductive drum; and a connecting member to allow the process roller to follow the movement of the photoconductive drum in the axial direction of the photoconductive drum.)
1. An electrophotographic image forming apparatus comprising:
a photoconductive drum;
a process roller to rotate in a state where the process roller elastically contacts a surface of the photoconductive drum; and
a connecting member to allow the process roller to follow movement of the photoconductive drum in an axial direction of the photoconductive drum, thereby maintaining a contact position between the process roller and the photoconductive drum in the axial direction.
2. An electrophotographic image forming apparatus according to claim 1, wherein the connecting member includes:
a flange fixed to an end of the photoconductive drum in a longitudinal direction of the photoconductive drum and including a groove engraved in a radial direction of the photoconductive drum; and
a retainer provided on the process roll, the retainer including a protrusion insertable into the groove, and the protrusion being spaced from a bottom of the groove when the protrusion is inserted into the groove.
3. An electrophotographic image forming apparatus according to claim 2, wherein the process roller is rotatably supported by the holder.
4. An electrophotographic image forming apparatus according to claim 2, wherein the holder further includes a separation portion protruding beyond the protrusion in a radial direction of the holder, and
the holder is movable between a first rotational position where the separating portion contacts the bottom of the groove and separates the process roller from the photoconductive drum and a second rotational position where the separating portion is spaced apart from the bottom of the groove and the protrusion is inserted into the groove.
5. An electrophotographic image forming apparatus according to claim 4, wherein when the holder is at the first rotational position and the photoconductive drum rotates, the holder moves from the first rotational position to the second rotational position.
6. The electrophotographic image forming apparatus according to claim 2, further comprising:
a pinion to rotate with the photoconductive drum when the photoconductive drum rotates in a process direction; and
a separation member, the separation member comprising:
a rack gear portion to engage the pinion gear; and
the insertion part is inserted into the cavity of the body,
wherein the separation member is movable between a first position in which the insertion portion is located between the bottom of the groove and the protrusion to separate the process roller from the photoconductive drum and a second position in which the insertion portion is released from between the bottom of the groove and the protrusion according to rotation of the pinion.
7. An electrophotographic image forming apparatus according to claim 6, wherein when the separation member is located at the second position, the engagement of the rack gear portion with the pinion gear is released.
8. An electrophotographic image forming apparatus according to claim 6, wherein the pinion gear is a photoconductive drum gear provided on an end of the photoconductive drum.
9. An electrophotographic image forming apparatus according to claim 6, further comprising a photoconductive drum gear provided on an end of the photoconductive drum,
wherein the pinion gear engages the photoconductive drum gear to rotate in association with rotation of the photoconductive drum gear.
10. The electrophotographic image forming apparatus according to claim 1, wherein the process roller includes at least one of a charging roller to charge the surface of the photoconductive drum to have a uniform electric potential, a developing roller to form a visible toner image by supplying toner on an electrostatic latent image formed on the surface of the photoconductive drum, and a transfer roller to transfer the toner image formed on the surface of the photoconductive drum to a recording medium.
11. An electrophotographic image forming apparatus comprising:
a photoconductive drum;
a process roller to rotate by elastically contacting a surface of the photoconductive drum;
a pinion gear to rotate when the photoconductive drum rotates in a process direction; and
a separation member, the separation member comprising:
a rack gear portion to engage the pinion gear; and
an insertion portion movable between a first position where the insertion portion is located between the process roller and the photoconductive drum to separate the process roller from the photoconductive drum and a second position where the insertion portion is withdrawn from the first position to allow the process roller to contact the photoconductive drum, according to rotation of the pinion.
12. An electrophotographic image forming apparatus according to claim 11, wherein when the insertion portion is located at the second position, the engagement of the rack gear portion with the pinion gear is released.
13. The electrophotographic image forming apparatus according to claim 12, further comprising:
a flange coupled to an end of the photoconductive drum in a longitudinal direction of the photoconductive drum; and
a holder for rotatably supporting the process roll,
wherein in the first position, the insert portion is located between the flange and the retainer.
14. An electrophotographic image forming apparatus according to claim 12, wherein said pinion gear is a photoconductive drum gear provided on an end portion of said photoconductive drum.
15. An electrophotographic image forming apparatus according to claim 12, further comprising a photoconductive drum gear provided on an end of said photoconductive drum,
wherein the pinion gear engages the photoconductive drum gear to rotate in association with rotation of the photoconductive drum gear.
Technical Field
The present disclosure relates to an electrophotographic image forming apparatus for printing an image on a recording medium by electrophotography.
Background
An electrophotographic image forming apparatus operating in an electrophotographic manner prints an image on a recording medium by supplying toner to an electrostatic latent image formed on a photoconductive drum, forming a visible toner image on the photoconductor, transferring the toner image to the recording medium, and fixing the transferred toner image to the recording medium.
An electrophotographic image forming apparatus includes a photoconductive drum and a process roller rotating in contact with a surface of the photoconductive drum. For example, the process roller may be a charging roller that charges the surface of the photoconductive drum to have a uniform electric potential, a developing roller that forms a visible toner image by supplying toner to the electrostatic latent image formed on the photoconductive drum, and a transfer roller that transfers the toner image to a recording medium.
The photoconductive drum is a rotating body and can move in the axial direction by receiving a thrust when rotating. Due to the movement of the photoconductive drum in the axial direction, the process roller may come into contact with an undesired area (non-contact area) on the surface of the photoconductive drum. Then, the high voltage applied to the process roller may leak through the non-contact area.
Drawings
Fig. 1 is a schematic configuration diagram showing an electrophotographic image forming apparatus according to an example;
fig. 2 illustrates an example of a connection structure between a photoconductive drum and a process roller;
fig. 3 is a sectional view of an example of the coupling relationship between the groove and the protrusion;
fig. 4 and 5 are schematic cross-sectional views of an example of a connection structure between a photoconductive drum and a process roller, in which fig. 4 illustrates a state in which the photoconductive drum and the process roller are separated from each other, and fig. 5 illustrates a state in which the photoconductive drum and the process roller are in contact with each other;
fig. 6 and 7 are schematic cross-sectional views of an example of a connection structure between a photoconductive drum and a process roller, in which fig. 6 illustrates a state in which the photoconductive drum and the process roller are separated from each other, and fig. 7 illustrates a state in which the photoconductive drum and the process roller are in contact with each other;
fig. 8 illustrates an example of a connection structure between a photoconductive drum and a process roller;
fig. 9 and 10 are schematic side views of fig. 8, in which fig. 9 shows a state in which the separating member is located at a first position, and fig. 10 shows a state in which the separating member is located at a second position; and
fig. 11 and 12 illustrate an example of a connection structure between a photoconductive drum and a process roller, in which fig. 11 illustrates a state in which a separation member is located at a first position, and fig. 12 illustrates a state in which the separation member is located at a second position.
Detailed Description
The present disclosure will now be described more fully with reference to the accompanying drawings, in which examples are shown. Like reference numerals in the drawings denote like elements, and their description will be omitted.
An electrophotographic image forming apparatus is disclosed in which a process roller is moved in accordance with movement of an axial direction of a photoconductive drum, thereby maintaining a stable contact position between the process roller and the photoconductive drum.
An electrophotographic image forming apparatus may include a photoconductive drum, a process roller to rotate in a state where the process roller elastically contacts a surface of the photoconductive drum, and a connecting member to allow the process roller to follow movement of the photoconductive drum in an axial direction of the photoconductive drum.
An electrophotographic image forming apparatus may include a photoconductive drum, a process roller to rotate by elastically contacting a surface of the photoconductive drum, a pinion to rotate together when the photoconductive drum rotates in a process direction, and a separation member including a rack gear portion connected to the pinion and an insertion portion. The separating member moves to a first position where the inserting portion is located between the process roller and the photoconductive drum to separate the process roller from the photoconductive drum or to a second position where the inserting portion is disengaged from the first position to allow the process roller to contact the photoconductive drum while the pinion rotates.
Fig. 1 is a schematic configuration diagram illustrating an electrophotographic image forming apparatus according to an example. Referring to fig. 1, the electrophotographic image forming apparatus includes a main body 100 and a developing device 200. An opening 101 providing a passage through which the developing device 200 is installed/removed may be formed in the main body 100. The cover 300 opens or closes the opening 101. The exposure device 110, the transfer roller 120, and the fixing device 130 are disposed at the main body 100. Further, a recording medium conveying structure 140 for loading and conveying a recording medium P on which an image is to be formed is disposed at the main body 100.
The developing device 200 includes a photoconductive drum 1. The photoconductive drum 1, as a photoconductor on which an electrostatic latent image is formed, may include a conductive metal tube and a photosensitive layer formed on the outer periphery of the conductive metal tube. The charging roller 2 is an example of a charger that charges the surface of the photoconductive drum 1 to have a uniform surface potential. A charging brush, a corona charger, or the like may be used instead of the charging roller 2. Reference numeral 3 denotes a cleaning roller that removes foreign matter adhering to the surface of the charging roller 2. The cleaning blade 8 is an example of a cleaning member that removes residual toner and foreign substances adhering to the surface of the photoconductive drum 1 after a transfer process to be described below. Another form of cleaning device, such as a rotary brush, may be used instead of the cleaning blade 8. The toner and foreign matter removed by the cleaning blade 8 are contained in the waste toner container 9.
The developing device 200 supplies the toner contained therein to the electrostatic latent image formed on the photoconductive drum 1, thereby developing the electrostatic latent image into a visible toner image. The developing device 200 includes a photoconductive drum 1 and a developing roller 4 opposed to the photoconductive drum 1.
When the one-component developing method is employed, toner is contained in the developing device 200. The single-component developing method may be classified into a contact developing method in which the developing roller 4 and the photoconductive drum 1 rotate in contact with each other, or a non-contact developing method in which the developing roller 4 and the photoconductive drum 1 rotate at an interval of several tens to several hundreds of micrometers from each other. The developing roller 4 supplies the toner in the developing device 200 to the photoconductive drum 1. A developing bias may be applied to the developing roller 4. The regulating member 5 regulates the amount of toner supplied by the developing roller 4 to a developing area where the photoconductive drum 1 and the developing roller 4 contact each other. The regulating member 5 may be a blade that elastically contacts the surface of the developing roller 4. The developing device 200 may further include a supply roller 6 that attaches toner to the surface of the developing roller 4. A supply bias may be applied to the supply roller 6. The developing device 200 may further include an agitator 7, and the agitator 7 agitates the toner and supplies the agitated toner to the supply roller 6 and the developing roller 4. The agitator 7 may agitate and triboelectrically charge the toner. At least two agitators 7 may be included as desired.
When the two-component developing method is employed, the toner and the carrier are contained in the developing device 200. The developing roller 4 is spaced from the photoconductive drum 1 by several tens to several hundreds of micrometers. Although not shown in fig. 1, the developing roller 4 may include a hollow cylindrical sleeve and a magnetic roller fixedly disposed within the hollow cylindrical sleeve. The toner adheres to the surface of the magnetic carrier. The magnetic carrier adheres to the surface of the developing roller 4 and is transferred to a developing area where the photoconductive drum 1 and the developing roller 4 contact each other. The toner is supplied to the photoconductive drum 1 due to a developing bias applied between the developing roller 4 and the photoconductive drum 1, and thus the electrostatic latent image formed on the surface of the photoconductive drum 1 is developed as a visible toner image. The developing device 200 may include a transfer agitator (not shown) that mixes the toner with the carrier, agitates the mixture, and transfers the agitated mixture to the developing roller 4. For example, the transfer agitator may be an auger, and the developing device 200 may include a plurality of transfer agitators.
Although an example of the developing method of the image forming apparatus according to the example has been described above, the present disclosure is not limited thereto, and various modifications may be made to the developing method.
The developing device 200 is an assembly of members for forming a visible toner image. The developing device 200 is a consumable part to be replaced at the end of its life. The developing device 200 may have any of various structures such as a structure in which the photoconductive drum 1, the developing roller 4, and the toner containing portion are integrally formed with each other, a structure in which an image forming unit including the photoconductive drum 1 and the developing roller 4 is distinguished from a toner unit containing toner, and a structure in which the photoconductive drum unit including the photoconductor, the developing unit including the developing roller, and the toner unit containing toner are distinguished from each other. Each unit can be replaced individually.
The exposure device 110 irradiates light modulated according to image information onto the photoconductive drum 1, and forms an electrostatic latent image on the photoconductive drum 1. Examples of the exposure device 110 may include a Laser Scanning Unit (LSU) using a laser diode as a light source and an LED exposure device using a Light Emitting Diode (LED) as a light source.
The transfer roller 120 is an example of a transfer device that transfers the toner image from the photoconductive drum 1 to the recording medium P. A transfer bias for transferring the toner image to the recording medium P is applied to the transfer roller 120. A corona transfer device or a needle scorotron type transfer device may be used instead of the transfer roller 120.
The recording medium P is picked up one by one from the loading table 141 by the pickup roller 142, and is conveyed to an area where the photoconductive drum 1 and the transfer roller 120 contact each other by the conveying rollers 143, 144, and 145.
The fixing device 130 applies heat and pressure to the toner image transferred onto the recording medium P, thereby fixing the toner image to the recording medium P. The recording medium P passing through the fixing device 130 is discharged to the outside of the main body 100 by the discharge roller 146.
According to the above-described structure, the exposure device 110 irradiates light modulated according to image information onto the photoconductive drum 1, and forms an electrostatic latent image. The developing roller 4 supplies toner to the electrostatic latent image, and forms a visible toner image on the surface of the photoconductive drum 1. The recording medium P is conveyed to an area where the photoconductive drum 1 and the transfer roller 120 contact each other by the pickup roller 142 and the conveying rollers 143, 144, and 145, and the toner image is transferred from the photoconductive drum 1 to the recording medium P due to a transfer bias applied to the transfer roller 120. When the recording medium P passes through the fixing device 130, the toner image is fixed on the recording medium P due to heat and pressure. The recording medium P on which the fixing is completed is discharged by the discharge roller 146.
When the duplex printing is performed, as the discharge roller 146 rotates backward, the recording medium P whose one surface has been printed is conveyed back to the area where the photoconductive drum 1 and the transfer roller 120 contact each other via the reverse conveying path 150. Next, a new toner image is transferred to the other surface of the recording medium P, subjected to a fixing process, and then the recording medium P having been double-sided printed is discharged by the discharge roller 146.
As described above, the electrophotographic printing process includes a charging process, a developing process, and a transfer process performed by a plurality of process rollers (such as the charging roller 2, the developing roller 4, and the transfer roller 120) arranged around the photoconductive drum 1. The charging roller 2 and the transfer roller 120 rotate in contact with the surface of the photoconductive drum 1. When the contact development method is used, the developing roller 4 also rotates in contact with the surface of the photoconductive drum 1. Elastic force is applied to the process rollers so that they can contact the photoconductive drum 1. The charging roller 2, the developing roller 4, and the transfer roller 120, which are in contact with the photoconductive drum 1, will now be referred to as process rollers, and the relationship between the process rollers and the photoconductive drum 1 will be described below.
Fig. 2 shows an example of a connection structure between the photoconductive drum 1 and the process roller 400. Referring to fig. 2, the process roller 400 is pressed to contact the surface of the photoconductive drum 1 due to the elastic force of the elastic member 410. As the photoconductive drum 1 rotates, the process roller 400 is driven due to a contact frictional force with the photoconductive drum 1. The process roller 400 may be rotated by receiving power from a power transmission member (not shown), such as a gear, coupled to a rotation shaft 401 (see fig. 3) of the process roller 400.
When the photoconductive drum 1 rotates, a force in the axial direction is applied to the photoconductive drum 1, and thus the photoconductive drum 1 can move in the axial direction. For example, in a case such as when the photoconductive drum gear 510 coupled to the end of the photoconductive drum 1 is a helical gear, when the thickness of the photosensitive layer 12 formed on the surface of the photoconductive drum 1 is not uniform in the longitudinal direction of the photoconductive drum 1, when the process roller 400 has a crown or inverted crown shape and the crown or inverted crown shape is not horizontally symmetrical, and when the process roller 400 and the photoconductive drum 1 are not parallel to each other (i.e., axial distances between the process roller 400 and the photoconductive drum 1 at both ends of the process roller 400 in the longitudinal direction thereof are different from each other), the photoconductive drum 1 and/or the process roller 400 may move in the axial direction.
When the photoconductive drum 1 and the process roller 400 are moved in connection with each other in the axial direction, the contact position of the photoconductive drum 1 and the process roller 400 in the longitudinal direction may be almost constant. When the photoconductive drum 1 and the process roller 400 are not moved in the axial direction from each other, that is, when the photoconductive drum 1 and the process roller 400 are independently moved in the axial direction, the contact position between the photoconductive drum 1 and the process roller 400 may be changed in the longitudinal direction.
The amount of movement of the photoconductive drum 1 and the process roller 400 in the axial direction and the moving direction thereof may vary depending on the above-described factors causing the axial movement of the photoconductive drum 1 and/or the process roller 400, and factors such as the driving torque transmitted to the photoconductive drum 1 and the process roller 400 and errors generated by the assembly of the constituent parts. Therefore, the contact position between the photoconductive drum 1 and the process roller 400 may not be kept constant.
The photoconductive drum 1 includes a conductive tube 11 and a photosensitive layer 12 formed on a surface of the conductive tube 11. Process roller 400 contacts photosensitive layer 12. Since photosensitive layer 12 is an electrical insulator when unexposed, a high voltage (e.g., a charging bias, a developing bias, or a transfer bias) can be maintained between photosensitive layer 12 and process roller 400 when a high voltage is applied to process roller 400. When the photoconductive drum 1 and the process roller 400 are independently moved in the axial direction, the process roller 400 may contact a region on which the photosensitive layer 12 is not formed, i.e., the outer circumference of the conductive tube 11. Then, when a high voltage (e.g., a charging bias voltage, a developing bias voltage, or a transfer bias voltage) is applied to the process roller 400, the high voltage may leak through the conductive pipe 11, so that charging, developing, or transfer defects may occur.
The image forming apparatus according to the example includes a connecting member that connects the photoconductive drum 1 to the process roller 400 so that the photoconductive drum 1 and the process roller 400 can move in connection with each other in the axial direction. In other words, the process roller 400 follows the movement of the photoconductive drum 1 in the axial direction due to the connecting member. According to this structure, the contact position between the process roller 400 and the photoconductive drum 1 can be kept constant.
Referring to fig. 2, the coupling member includes a groove 501 provided on an end of the photoconductive drum 1 in a longitudinal direction thereof, and a protrusion 421 provided on an end of the process roller 400 and inserted into the groove 501. For example, a flange 500 may be fixed to an end of the photoconductive drum 1 in the longitudinal direction thereof, and a groove 501 may be formed on the flange 500. The flange 500 may be integrally formed with the photoconductive drum gear 510. The groove 501 may have an annular shape that is indented from the outer periphery of the flange 500 in the radial direction thereof. The protrusions 421 may be provided on the holder 420 coupled to the end of the process roller 400.
Fig. 3 is a sectional view showing the coupling relationship between the groove 501 and the protrusion 421. Referring to fig. 3, the holder 420 has a hole 422, and the rotation shaft 401 of the process roller 400 is rotatably inserted into the hole 422. The protrusion 421 is inserted into the groove 501. The end 421a of the protrusion 421 does not contact the bottom 502 of the groove 501 so as not to affect the contact force between the process roller 400 and the photoconductive drum 1. In other words, when the process roller 400 is in contact with the photoconductive drum 1, the end portion 421a of the protrusion 421 does not contact the bottom 502 of the groove 501. Although not shown in fig. 3, the protrusion 421 may be in the shape of a circular disk protruding completely from the outer circumference of the holder 420.
According to this structure, the movement of the process roller 400 in the axial direction follows the movement of the photoconductive drum 1 in the axial direction. In other words, when the photoconductive drum 1 moves in the axial direction, the protrusion 421 is pushed by the groove 501, and therefore the process roller 400 also moves in the same direction as the moving direction of the photoconductive drum 1 by the same moving amount as the photoconductive drum 1. The movement of the process roller 400 in the axial direction is restricted by the grooves 501 and the protrusions 421. Therefore, the contact position between the photoconductive drum 1 and the process roller 400 can be kept constant, and the occurrence of image defects during charging, development, and transfer can be prevented.
The holder 420 and the process roller 400 may be coupled to each other such that the process roller 400 follows the movement of the photoconductive drum 1 in the axial direction. For example, according to an example, a flange 500 on which a groove 501 is formed is provided on each of both end portions of the photoconductive drum 1, and a holder 420 having a protrusion 421 is provided on each of both end portions of the process roller 400. A step 402 may be provided on each of both ends of the rotation shaft 401. According to this structure, when the photoconductive drum 1 moves in the direction D1, the holder 420 provided on the right side of fig. 2 is pushed in the direction D1, and the holder 420 pushes the step 402, so that the process roller 400 also moves in the direction D1. When the photoconductive drum 1 moves in the direction D2, the holder 420 provided on the left side of fig. 2 is pushed in the direction D2, and the holder 420 pushes the step 402, so that the process roller 400 also moves in the direction D2.
The coupling structure between holder 420 and rotary shaft 401 is not limited to the above-described example. For example, although not shown in fig. 3, a locking member (e.g., an E-ring) that couples the holder 420 to the rotary shaft 401 to prevent the holder 420 from moving in the axial direction may be locked to the rotary shaft 401 on one or both sides of the holder 420.
The image forming apparatus is exposed to various environments during dispensing after manufacture. When a long time has elapsed with the process roller 400 being in contact with the photoconductive drum 1, the photoconductive drum 1 and the process roller 400 may be physically and chemically damaged. For example, when the photoconductive drum 1 and the process roller 400 are exposed to a high temperature and high humidity environment, they may be damaged. Physical and chemical damage of the photoconductive drum 1 and the process roller 400 may cause image defects. For example, the printed image may be defective at the rotation period interval of the photoconductive drum 1 or the process roller 400.
To solve this problem, the process roller 400 and the photoconductive drum 1 may be dispensed while being separated from each other, and when the user uses the image forming apparatus, a structure of bringing the process roller 400 into contact with the photoconductive drum 1 while the photoconductive drum 1 is rotated may be employed. According to an example, a connecting member may be used to space/contact the photoconductive drum 1 from the process roller 400.
Fig. 4 and 5 are schematic sectional views of examples of a connection structure between the photoconductive drum 1 and the process roller 400. Fig. 4 illustrates a state in which the photoconductive drum 1 and the process roller 400 are separated from each other, and fig. 5 illustrates a state in which the photoconductive drum 1 and the process roller 400 are in contact with each other.
Referring to fig. 4, the holder 420 includes a separation portion 423 protruding further beyond the protrusion 421 in the radial direction. The protruding amount of the separation portion 423 is determined such that the process roller 400 can be separated from the photoconductive drum 1 while being in contact with the bottom 502 of the groove 501. Although not shown in fig. 4 and 5, the protrusion 421 may be in a disc shape completely protruding from the outer circumference of the holder 420, and the separating portion 423 may be shaped to protrude from the disc-shaped protrusion 421.
The holder 420 has a first rotational position (fig. 4) where the separating portion 423 contacts the bottom 502 of the groove 501, thus separating the process roller 400 from the photoconductive drum 1, and a second rotational position (fig. 5) where the separating portion 423 is spaced apart from the bottom 502 of the groove 501 and the protrusion 421 is inserted into the groove 501, the holder 420 is rotatable with respect to the process roller 400, and is rotatable from the first rotational position to the second rotational position.
According to an example, the rotation of the holder 420 from the first rotational position to the second rotational position is associated with the rotation of the photoconductive drum 1 in the process direction PR. In the first rotation position, the separation portion 423 is in contact with the bottom 502 of the groove 501 due to the elastic force of the elastic member 410, and the separation portion 423 presses the bottom 502. Therefore, when the photoconductive drum 1 rotates in the process direction PR, the holder 420 may rotate due to friction between the bottom 502 and the separation portion 423.
First, referring to fig. 4, the separation portion 423 is located at a first rotation position where the separation portion 423 contacts the bottom 502 of the groove 501 and thus separates the process roller 400 from the photoconductive drum 1. The separation portion 423 maintains contact with the bottom 502 of the groove 501 due to the elastic force of the elastic member 410, and the process roller 400 maintains separation from the photoconductive drum 1.
When the operation of the image forming apparatus is started in this state, the photoconductive drum 1 rotates in the process direction PR as illustrated in fig. 5. Since the separation portion 423 is in contact with the bottom 502 of the groove 501, the holder 420 rotates due to friction between the separation portion 423 and the bottom 502 of the groove 501. The process roller 400 approaches the photoconductive drum 1 due to the elastic force of the elastic member 410. When the contact between the separation portion 423 and the bottom 502 is terminated, the process roller 400 contacts the photoconductive drum 1. The holder 420 reaches the second rotational position and the protrusion 421 is inserted into the groove 501. Therefore, in the second rotation position, the process roller 400 can follow the movement of the photoconductive drum 1 in the axial direction.
According to this structure, when the manufacturing of the image forming apparatus is completed, the image forming apparatus is dispensed while the holder 420 is in the first rotational position. Accordingly, physical and chemical damage to the photoconductive drum 1 and the process roller 400 due to long-term maintenance of contact between the process roller 400 and the photoconductive drum 1, and image defects due to physical and chemical damage to the photoconductive drum 1 and the process roller 400 can be prevented. When the user obtains the image forming apparatus and the operation of the image forming apparatus starts, the process roller 400 is in contact with the photoconductive drum 1 while the holder 420 is rotated to the second rotation position, and thus the image forming apparatus is in a printable state. Therefore, a user does not need a manipulation for bringing the process roller 400 into contact with the photoconductive drum 1, and thus user convenience can be improved.
The above-described problems that may occur due to the long-time contact between the process roller 400 and the photoconductive drum 1 may be solved by using a removable separation member.
Fig. 6 and 7 are schematic sectional views of examples of a connection structure between the photoconductive drum 1 and the process roller 400. Fig. 6 illustrates a state in which the photoconductive drum 1 and the process roller 400 are separated from each other, and fig. 7 illustrates a state in which the photoconductive drum 1 and the process roller 400 are in contact with each other. In the example of fig. 6 and 7, a removable detachment member 600 is employed.
Referring to fig. 6, a separating member 600 is interposed between the process roller 400 and the photoconductive drum 1 and separates the process roller 400 from the photoconductive drum 1. For example, the separation member 600 is inserted into the groove 501. The protrusion 421 contacts the separating member 600. Therefore, the protrusions 421 are not inserted into the grooves 501 or are not completely inserted into the grooves 501, and thus the process roller 400 is separated from the photoconductive drum 1. The removable separation member 600 may be partially exposed to the outside of the housing 201 (see fig. 1) of the developing device 200 such that the removable separation member 600 can be accessed by a user.
When the separation member 600 is removed as shown in fig. 7, the process roller 400 is pushed toward the photoconductive drum 1 due to the elastic force of the elastic member 410, and the protrusions 421 are inserted into the grooves 501. The process roller 400 contacts the photoconductive drum 1. At this time, as described above, the protrusion 421 is spaced apart from the bottom 502 of the groove 501. Since the protrusions 421 are in a state of being inserted into the grooves 501, the process roller 400 can follow the movement of the photoconductive drum 1 in the axial direction.
When the process roller 400 is the transfer roller 120, the separation member 600 is removed after the developing device 200 is removed from the main body 100, and thus the holder 420 is not rotated when the separation member 600 is removed. When the process roller 400 is the charging roller 2 or the developing roller 4, the protrusion 421 presses the separation member 600 due to the elastic force of the elastic member 410 even when the developing device 200 is removed from the main body 100. Thus, when the separation member 600 is removed, the holder 420 may be rotated. When the protrusion 421 protrudes from the outer circumferential portion of the holder 420 as shown in fig. 6 and 7, the width W of the protrusion 421 may be determined such that the holder 420 does not rotate when the separation member 600 is removed. According to this structure, when the process roller 400 contacts the photoconductive drum 1 after the separation member 600 is removed, the protrusions 421 may be inserted into the grooves 501. Although not shown in fig. 6 and 7, when the protrusion 421 has a disk shape and the process roller 400 is in contact with the photoconductive drum 1, the protrusion 421 may be inserted into the groove 501 even when the holder 420 is rotated when the separation member 600 is removed.
According to this structure, when the manufacturing of the image forming apparatus is completed, the image forming apparatus is dispensed when the separation member 600 is inserted into the groove 501. Accordingly, physical and chemical damage to the photoconductive drum 1 and the process roller 400 due to long-term maintenance of contact between the process roller 400 and the photoconductive drum 1, and image defects due to physical and chemical damage to the photoconductive drum 1 and the process roller 400 can be prevented. When the user obtains the image forming apparatus, the user brings the process roller 400 into contact with the photoconductive drum 1 by removing the separation member 600 before using the image forming apparatus. The image forming apparatus is in a printable state. Further, since the protrusions 421 are inserted into the grooves 501, the process roller 400 can follow the movement of the photoconductive drum 1 in the axial direction.
An example in which the separation member 600 is disengaged from the groove 501 when the image forming apparatus is operating, i.e., in association with the rotation of the photoconductive drum 1 in the process direction PR is possible.
Fig. 8 illustrates an example of a connection structure between the photoconductive drum 1 and the process roller 400. Fig. 9 is a schematic side view of fig. 8, and shows a state in which the separation member 600 is located at the first position. Fig. 10 is a schematic side view of fig. 8, and shows a state in which the separation member 600 is located at the second position. In fig. 9 and 10, the process roller 400 and the holder 420 are omitted.
Referring to fig. 8 to 10, the separating member 600 includes an insertion portion 610 and a rack gear portion 620. The insertion portion 610 is inserted into the groove 501 or disengaged from the groove 501 according to the position of the separation member 600. As the photoconductive drum 1 rotates in the process direction PR, the separation member 600 moves from a first position where the insertion portion 610 has been inserted into the groove 501 to a second position where the insertion portion 610 has been disengaged from the groove 501. In the first position, the insertion portion 610 is located between the bottom 502 of the groove 501 and the protrusion 421 and separates the process roller 400 from the photoconductive drum 1. In the second position, the insertion portion 610 is disengaged from between the bottom 502 of the groove 501 and the protrusion 421, and the protrusion 421 is allowed to be inserted into the groove 501, and the process roller 400 is allowed to contact the photoconductive drum 1.
The separation member 600 may be supported to be slidable to the housing 201 of the developing device 200 (see fig. 1). A pinion gear interlocked with the rack gear portion 620 is provided to move the separation member 600 from the first position to the second position. When the photoconductive drum 1 rotates in the process direction PR, the pinion also rotates. For example, the pinion may be a photoconductive drum gear 510 coupled to the photoconductive drum 1.
Referring to fig. 9, the separating member 600 is located at the first position. The insertion portion 610 is located on the recess 501. The protrusion 421 contacts the insertion portion 610. The protrusion 421 is not inserted into the groove 501 or is not sufficiently inserted into the groove 501, and the process roller 400 is separated from the photoconductive drum 1. The rack gear portion 620 interlocks with the photoconductive drum gear 510.
When the operation of the image forming apparatus is started in this state and the photoconductive drum gear 510 rotates in the process direction PR, the separation member 600 slides and moves to the second position as illustrated in fig. 10. The insertion portion 610 is disengaged from the recess 501. Then, the process roller 400 contacts the photoconductive drum 1 due to the elastic member 410, and the protrusions 421 are inserted into the grooves 501. At this time, as described above, the protrusion 421 is spaced apart from the bottom 502 of the groove 501. Since the protrusions 421 are in a state of being inserted into the grooves 501, the process roller 400 can follow the movement of the photoconductive drum 1 in the axial direction.
When the protrusion 421 has a shape protruding from the outer circumferential portion of the holder 420 as shown in fig. 8 to 10, the width W (see fig. 6) of the protrusion 421 may be determined such that the holder 420 does not rotate when the separation member 600 is removed. According to this structure, when the process roller 400 contacts the photoconductive drum 1 after the separation member 600 is removed, the protrusions 421 may be inserted into the grooves 501. Although not shown in fig. 8 to 10, when the protrusion 421 has a disk shape and the process roller 400 is in contact with the photoconductive drum 1, the protrusion 421 may be inserted into the groove 501 even when the holder 420 is rotated when the separation member 600 is removed.
The interlock between the rack gear portion 620 and the photoconductive drum gear 510 is released (released) in the second position. Therefore, even when the photoconductive drum 1 rotates in the direction opposite to the process direction PR, the separation member 600 does not return to the first position.
According to this structure, when the manufacturing of the image forming apparatus is completed, the image forming apparatus is dispensed while the separation member 600 is located at the first position. Accordingly, physical and chemical damage to the photoconductive drum 1 and the process roller 400 due to long-term maintenance of contact between the process roller 400 and the photoconductive drum 1, and image defects due to physical and chemical damage to the photoconductive drum 1 and the process roller 400 can be prevented. When a user obtains the image forming apparatus and the operation of the image forming apparatus starts, the separation member 600 slides to the second position as the photoconductive drum 1 rotates in the process direction PR, and the process roller 400 contacts the photoconductive drum 1, so the image forming apparatus is in a printable state. Therefore, a user does not need a manipulation of bringing the process roller 400 into contact with the photoconductive drum 1, and thus user convenience can be improved. Further, since the protrusions 421 are inserted into the grooves 501, the process roller 400 can follow the movement of the photoconductive drum 1 in the axial direction.
Fig. 11 and 12 illustrate an example of a connection structure between the photoconductive drum 1 and the process roller 400. Fig. 11 illustrates a state in which the separation member 600 is located at the first position. Fig. 12 shows a state where the separation member 600 is located at the second position. The example of fig. 11 and 12 is different from the example of fig. 8 to 10 in that a pinion 630 rotates in association with the photoconductive drum gear 510. In the example of fig. 11 and 12, the disengaging direction of the separating member 600 is opposite to that in the example of fig. 8 to 10.
In the examples of fig. 8 to 12, the structure of moving the process roller 400 from the position where the process roller 400 is separated from the photoconductive drum 1 to the position where the process roller 400 contacts the photoconductive drum 1 while the photoconductive drum 1 is driven in the process direction PR forms the concept of the present disclosure. The electrophotographic image forming apparatus includes a pinion 510 or 630 and a separating member 600, the pinion 510 or 630 also rotates when the photoconductive drum 1 rotates in the process direction. The separating member 600 includes a rack gear part 620 connected to the pinion 510 or 630 and moves to a first position (fig. 9 and 11) where the separating member 600 is inserted between the process roller 400 and the photoconductive drum 1 and separates the process roller 400 from the photoconductive drum 1, or to a second position (fig. 10 and 12) where the separating member 600 is disengaged from the first position and the process roller 400 contacts the photoconductive drum 1 as the pinion rotates. When the separation member 600 is located at the second position, the interlock between the rack gear portion 620 and the pinion 510 or 630 is released. Although not shown in fig. 8 to 12, in the first position, the separation member 600 may be located between the surface of the photoconductive drum 1 and the process roller 400. In the first position, the separation member 600 may be located between the surface of the photoconductive drum 1 and the supported holder 420 so that the process roller 400 may rotate. The flange 500 may be coupled to an end of the photoconductive drum 1 in a longitudinal direction of the photoconductive drum 1, and in the first position, the separation member 600 may be located between the flange 500 and the holder 420.
According to this structure, since the image forming apparatus dispenses when the separating member 600 is located at the first position, image defects due to the long-term maintenance of the process roller 400 in contact with the photoconductive drum 1 can be prevented. Further, when the operation of the image forming apparatus is started, the separation member 600 is moved to the second position, and thus the image forming apparatus is in a printable state, thereby improving user convenience.
The above-described examples of the connection structure between the photoconductive drum 1 and the process roller 400 can be applied between the photoconductive drum 1 and the charging roller 2, between the photoconductive drum 1 and the developing roller 4, and between the photoconductive drum 1 and the transfer roller 120.
According to the above-described example of the electrophotographic image forming apparatus, the stability of the contact position between the process roller and the photoconductive drum can be maintained, and a stable image can be realized.
According to the above-described example of the electrophotographic image forming apparatus, the process roller and the photoconductive drum may contact/may be separated from each other.
Although examples have been described with reference to the accompanying drawings, those of ordinary skill in the art will understand that various changes in form and details may be made therein without departing from the spirit and scope defined by the following claims.
