Photoconductor unit

Abstract

To prevent, in a state in which a photoreceptor and an electrifying roller are separated from each other with the engagement between an engagement part of a separation member and a photoreceptor gear, the separation state between the photoconductor and the electrifying roller from being unintentionally cancelled, even when a force is applied in which the engagement part of the separation member moves in a direction separating from the photoreceptor gear.SOLUTION: A photoreceptor unit comprises: a separation member for separating an electrifying roller and a photoreceptor from each other; a guide unit that, in a state in which an engagement part of the separation member and a gear are engaged with each other, guides an electrifying roller bearing member urged by an urging member to separate the electrifying roller from the photoreceptor, and in a state in which the engagement part and the gear are not engaged with each other, guides the electrifying roller bearing member urged by the urging member to bring the electrifying roller into contact with the photoreceptor; and a frame that supports the photoreceptor. In a state in which the engagement part and the gear are engaged with each other, when the distance between the electrifying roller bearing member urged by the urging member and the frame is A, and the length of the engagement between the engagement part and the gear is B, A<B is satisfied.SELECTED DRAWING: Figure 15

Description

[Technical Field]

[0001] The present invention relates to a photosensitive unit that can be installed in an image forming apparatus that utilizes an electrophotographic process. [Background technology]

[0002] To facilitate maintenance, electrophotographic image forming apparatuses are known that employ a system in which a photosensitive unit that integrates a photosensitive member and a charging roller that charges the photosensitive member is replaced. Furthermore, image forming apparatuses employing such a system often employ a contact charging system in which a charging roller having an elastic layer is brought into contact with the photosensitive member by the biasing force of a spring or the like to charge the photosensitive member.

[0003] In such a contact charging method, if the photosensitive unit is left in contact with the charging roller and photosensitive member for a long period of time, the part of the charging roller that was in contact with the photosensitive member may become deformed, which may result in poor image formation.

[0004] To prevent such image defects, a known configuration is to ship the photosensitive unit with a spacer sandwiched between the photosensitive element and the charging roller, and then to install the photosensitive element unit in the image forming apparatus main body after removing the spacer.

[0005] However, with this configuration, there is a problem in that the user has to take the trouble of removing the spacer when mounting the photosensitive unit to the image forming apparatus main body.

[0006] Therefore, Patent Document 1 discloses a configuration in which the charge roller, which has been spaced apart, comes into contact with the photosensitive member by the rotation of the photosensitive member without the user having to remove the spacer when installing the photosensitive member unit in the image forming apparatus body. Specifically, the configuration separates the photosensitive member and the charge roller while a fan-shaped engaging portion at the tip of a spacer fitted onto the rotation shaft of the charge roller engages with a photosensitive member gear provided coaxially with the photosensitive member. When the spacer rotates due to the rotation of the photosensitive member, the photosensitive member gear and the spacer are disengaged, bringing the photosensitive member into contact with the charge roller.

[0007] However, in the configuration of Patent Document 1, the photoconductor rotates due to vibrations applied to the photoconductor unit during transportation, for example, from the time the photoconductor unit is shipped until it is installed in the image forming apparatus body. As a result, the rotation of the photoconductor may cause the spacing member to come off, potentially causing the photoconductor and charging roller to come into contact unintentionally.

[0008] Therefore, Patent Document 2 describes a configuration in which an engaging portion of a spacing member is engaged with the gear of the photosensitive member and the engaging portion is pressed against the gear when the photosensitive member and the charging roller are separated from each other. With this configuration, the engaging portion is pressed against the gear, making it difficult for the gear to rotate. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 11-95532 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-133775 Summary of the Invention [Problem to be solved by the invention]

[0010] However, before the photosensitive unit is attached to the image forming apparatus main body, strong vibrations may be applied to the photosensitive unit, causing the spacing member to move together with the charging roller in a direction away from the photosensitive member. As a result, in the configuration of Cited Document 2, when a force is applied that moves the spacing member together with the charging roller in a direction away from the photosensitive member, if the engagement portion separates from the gear of the photosensitive member, the spacing member, which has become freely rotatable, may rotate and release the separated state.

[0011] Therefore, the object of the present invention is to provide a photosensitive unit that can prevent the separation state between the photosensitive element and the charging roller from being unintentionally released even when a force acts to move the engaging portion of the spacing member in a direction away from the photosensitive element gear when the photosensitive element and the charging roller are separated by engagement between the engaging portion of the spacing member and the photosensitive element gear. [Means for solving the problem]

[0012] The present invention provides a photosensitive unit that can be installed in an image forming apparatus, comprising: a rotatable photosensitive member; a rotatable charging roller that contacts the photosensitive member and charges the photosensitive member; a charging roller bearing member that is attached to a rotation shaft of the charging roller and rotatably supports the charging roller; a biasing member that is provided on the charging roller bearing member and biases the charging roller toward the photosensitive member; and a biasing member that biases the charging roller toward the photosensitive member in the direction of the rotation axis of the photosensitive member. first a gear provided at an end of the charge roller; a spacing member provided on a rotation shaft of the charge roller, the spacing member having an engaging portion that engages with the gear, for spacing the charge roller and the photosensitive member; and a guide portion that guides the charge roller bearing member urged by the urging member so that the charge roller is spaced from the photosensitive member when the engaging portion and the gear are engaged, and that guides the charge roller bearing member urged by the urging member so that the charge roller comes into contact with the photosensitive member when the engaging portion and the gear are not engaged. a first side wall disposed at the first end of the photosensitive member in the rotational axis direction, a second side wall disposed at the second end of the photosensitive member in the rotational axis direction, and a connecting portion connecting the first side wall and the second side wall, The photoreceptor Rotatable a frame supporting the charging roller bearing member, the charging roller bearing member being biased by the biasing member when the engaging portion and the gear are engaged with each other; End face ofand the above-mentioned first side wall When the shortest distance to is A, and the engagement amount between the engaging portion and the gear in the state where the engaging portion and the gear are engaged is B, it is characterized in that A < B is satisfied.

Advantages of the Invention

[0013] According to the present invention, even when a force acts in a direction in which the engaging portion of the separation member moves away from the photosensitive member gear in a state where the photosensitive member and the charging roller are separated by the engagement between the engaging portion of the separation member and the photosensitive member gear, it is possible to suppress the unintentional elimination of the separated state between the photosensitive member and the charging roller.

Brief Description of the Drawings

[0014] [Figure 1] Schematic cross-sectional view of the schematic configuration of an image forming apparatus according to the first embodiment. [Figure 2] Schematic cross-sectional view of the schematic configuration of a drum unit according to the first embodiment. [Figure 3] Partial perspective view showing the contact state of the drum unit according to the first embodiment, omitting the restricting portion. [Figure 4] Partial perspective view showing the contact state of the drum unit according to the first embodiment, omitting the restricting portion, the separation member, and the frame. [Figure 5] Partial perspective view showing the separated state of the drum unit according to the first embodiment, omitting the restricting portion. [Figure 6] Partial perspective view showing the separated state of the drum unit according to the first embodiment, omitting the restricting portion and the frame. [Figure 7] Schematic cross-sectional views respectively showing (a) the separated state and (b) the state where the separated state is released of the separation member according to the first embodiment. [Figure 8] Partial perspective view showing the separated state of the drum unit according to the reference example. [Figure 9] Partial perspective views of the drum unit according to the reference example, (a) showing the separated state omitting the frame, and (b) showing the photosensitive drum and the frame. [Figure 10]FIG. 10A is a partial side view showing a separated state of the drum unit according to the reference example, and FIG. 10B is a cross-sectional view taken along the line XX in FIG. [Figure 11] 10(b) is a diagram similar to FIG. 10(b), showing (a) the direction of the torque acting when the abutting portion abuts against the abutted portion in the reference example, and (b) the relationship between the direction of the force acting on the spacing member and the normal vector at the abutting portion. [Figure 12] FIG. 2 is a perspective view showing a spacing maintaining section which is a configuration of an example of the present invention in the first embodiment. [Figure 13] FIG. 2 is a perspective view showing a spacing maintaining section which is a configuration of an example of the present invention in the first embodiment. [Figure 14] FIG. 10 is a cross-sectional view showing the configuration of a modified example of the present invention. [Figure 15] FIG. 10 is a cross-sectional view showing the configuration of a modified example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] First Embodiment A first embodiment of the present invention will be described with reference to Figures 1 to 11. First, a schematic configuration of an image forming apparatus according to this embodiment will be described with reference to Figure 1.

[0016] [Image forming equipment] The image forming apparatus 1 is a tandem-type image forming apparatus that employs an intermediate transfer system and is capable of forming full-color images using an electrophotographic system. That is, the image forming apparatus 1 has image forming units 10 for each of the colors Y (yellow), M (magenta), C (cyan), and K (black), and is configured as a so-called tandem-type, in which the image forming units 10 for each color are arranged side by side in the rotation direction of an intermediate transfer belt 61. The configuration and operation of each image forming unit 10 are substantially identical, except that the color of toner used is different.

[0017] Each image forming unit 10 has a photosensitive drum 11, which is a cylindrical electrophotographic photosensitive member (photoconductor). The photosensitive drum 11 is driven to rotate at a process speed (circumferential speed) of 100 mm / sec by a driving force transmitted from a driving unit (not shown) provided in the apparatus main body 1a. In the image forming unit 10, a charging roller 12, a developing device 14, a primary transfer roller 17, and a drum cleaning device 15 are arranged around the photosensitive drum 11 in this order along the direction of rotation. An exposure device 16 is arranged below each image forming unit 10. The image forming apparatus 1 also has an intermediate transfer belt 61, which is an endless belt and serves as an intermediate transfer member, in contact with the photosensitive drum 11 of each image forming unit 10.

[0018] The charging roller 12 serving as charging means is a rotatable roller-shaped charging member that is disposed so as to contact the photosensitive drum 11 and charges the surface of the photosensitive drum 11. The exposure device (laser scanner device) 16 serving as exposure means exposes the surface of the charged photosensitive drum 11 to light to form an electrostatic latent image on the surface of the photosensitive drum 11.

[0019] The developing device 14 as a developing means contains toner as a developer therein, and uses the toner to develop the electrostatic latent image formed on the photosensitive drum 11 into a toner image. The developing device 14 has a developing sleeve 14a as a developer carrier that carries the toner and transports it to a position facing the photosensitive drum 11 (developing position). The developing sleeve 14a is driven to rotate.

[0020] The primary transfer roller 17 as a primary transfer means is a roller-shaped primary transfer member, and performs primary transfer of the toner image formed on the photosensitive drum 11 onto the intermediate transfer belt 61. The drum cleaning device 15 cleans the residual toner remaining on the photosensitive drum 11 after the primary transfer.

[0021] The intermediate transfer belt 61 is made of a dielectric resin such as polyimide and is endless. The intermediate transfer belt 61 is wound around a plurality of support rollers (tension rollers) with a predetermined tension. The above-mentioned primary transfer rollers 17 are disposed on the inner peripheral surface (back surface) of the intermediate transfer belt 61 at positions facing the respective photosensitive drums 11. The primary transfer rollers 17 are pressed against the photosensitive drums 11 via the intermediate transfer belt 61, forming a primary transfer portion (primary transfer nip portion) N1 where the intermediate transfer belt 61 and the photosensitive drums 11 come into contact. The primary transfer rollers 17 are rotated in accordance with the rotation of the intermediate transfer belt 61.

[0022] Furthermore, a secondary transfer roller 35, which is a roller-shaped secondary transfer member serving as secondary transfer means, is disposed at a position facing the secondary transfer opposing roller 62 on the outer peripheral surface side (surface side) of the intermediate transfer belt 61. The secondary transfer roller 35 is pressed against the secondary transfer opposing roller 62 via the intermediate transfer belt 61, forming a secondary transfer portion (secondary transfer nip portion) N2 where the intermediate transfer belt 61 and the secondary transfer roller 35 come into contact. The toner image transferred onto the intermediate transfer belt 61 is secondarily transferred onto the recording material P at the secondary transfer portion N2.

[0023] Furthermore, a belt cleaning device 70 serving as an intermediate transfer body cleaning means is disposed at a position facing the tension roller 64 on the outer peripheral surface side of the intermediate transfer belt 61. The belt cleaning device 70 cleans the residual toner and the like remaining on the intermediate transfer belt 61 after the secondary transfer.

[0024] Next, the image forming operation will be described. During image formation, the surface of the rotationally driven photosensitive drum 11 is uniformly charged to a predetermined potential of a predetermined polarity by the charging roller 12. In this embodiment, only a DC voltage of -1300 V is applied to the charging roller 12 from a high-voltage power supply (charging power supply) (not shown), causing discharge on the surface of the photosensitive drum 11, and the surface of the photosensitive drum 11 is charged to approximately -700 V.

[0025] After the surface of the photosensitive drum 11 is uniformly charged, the surface of the photosensitive drum 11 is scanned and exposed by the exposure device 16 based on the image information signal, and an electrostatic latent image (electrostatic image) is formed on the photosensitive drum 11. Note that the image forming apparatus 1 of this embodiment is equipped with an image reading device 2, and the image information described above includes image information of a document read by the image reading device 2 and image information sent from an external terminal such as a personal computer connected to the image forming apparatus 1.

[0026] The electrostatic latent image formed on the photosensitive drum 11 is developed into a toner image by the developing device 14 using toner as a developer. In this embodiment, the normal charge polarity of the toner is negative. During development, a predetermined development voltage (development bias) is applied to the developing sleeve 14a from a high-voltage power supply (not shown) serving as a development power supply. The development voltage used is an oscillating voltage in which a DC voltage (DC component) and an AC voltage (AC component) are superimposed. Toner is supplied to the developing device 14 from a toner bottle 19 serving as a toner storage container via a toner transport path (not shown).

[0027] The toner image formed on the photosensitive drum 11 is transferred (primary transfer) onto the surface of the intermediate transfer belt 61 by the action of the primary transfer roller 17 in the primary transfer section N1. At this time, a primary transfer voltage (primary transfer bias), which is a DC voltage of the opposite polarity (positive polarity in this embodiment) to the charge polarity of the toner during development, is applied to the primary transfer roller 17 from a primary transfer power supply (high voltage power supply) not shown. When a full-color image is formed, the above-mentioned operation is performed in each image forming section 10, and the toner images of each color, yellow, magenta, cyan, and black, formed on each photosensitive drum 11 are transferred onto the intermediate transfer belt 61 so as to be superimposed one on top of the other. After transfer, the small amount of residual toner remaining on the photosensitive drum 11 is removed by the drum cleaning device 15 and collected by the collection section 16. 15b will be collected.

[0028] Meanwhile, recording materials P are fed one by one from the feeding cassette 20 and conveyed to the registration roller pair 23. The recording materials P are, for example, sheets of paper, plastic sheets, etc. Thereafter, the registration roller pair 23 conveys the recording materials P between the intermediate transfer belt 61 and the secondary transfer roller 35 in synchronization with the toner image on the intermediate transfer belt 61.

[0029] The color toner image on the intermediate transfer belt 61 is transferred (secondary transfer) onto the surface of the recording material P at the secondary transfer portion N2 by the action of the secondary transfer roller 35. When this recording material P passes through the secondary transfer portion N2, a secondary transfer voltage (secondary transfer bias), which is a DC voltage of opposite polarity to the charge polarity of the toner during development, is applied to the secondary transfer roller 35 from a secondary transfer power supply (high voltage power supply) not shown. After transfer, the small amount of residual toner remaining on the intermediate transfer belt 61 is removed and collected by the belt cleaning device 70, and the intermediate transfer belt 61 is again prepared for the next image formation.

[0030] The toner image transferred onto the recording material P is fixed by being heated and pressed at the nip between the heating roller 41 and the pressure roller 42 of the fixing device 40, and is then discharged onto a discharge tray 51 by a pair of discharge rollers 50.

[0031] [Drum cartridge] Next, the schematic configuration of the drum cartridge 100 as a photosensitive unit will be described with reference to Figures 2 to 4. In this embodiment, the drum cartridge 100 having the photosensitive drum 11 is detachable from the device main body 1a (Figure 1) so that it can be replaced for maintenance or the like. For example, the drum cartridge 100 can be detachable from the device main body 1a by moving it along the longitudinal direction (the direction of the rotation axis of the photosensitive drum 11) relative to the device main body 1a.

[0032] 2, the drum cartridge 100 includes a photosensitive drum 11 as a photosensitive member, a charging roller 12, a cleaning roller 13 as a cleaning member, a drum cleaning device 15, and a resin spacing member 200. These components are integrally held by a drum container 30 as a frame.

[0033] The photosensitive drum 11 is held in the drum container 30 via bearings (not shown) so as to be rotatable about the rotation axis. That is, as shown in Fig. 3, the drum container 30 has side walls 30a arranged on both sides in the rotation axis direction of the photosensitive drum 11, charging roller 12, and cleaning roller 13, and a connecting portion 30b connecting the side walls 30a on both sides. Both ends of the photosensitive drum 11 in the rotation axis direction are rotatably supported by the side walls 30a on both sides in the rotation axis direction via bearings, respectively.

[0034] The photosensitive drum 11 is also provided with a coupling 39 (FIG. 4) for receiving a driving force from a motor (not shown) provided in the apparatus main body 1a as a driving source and rotating the photosensitive drum 11 when the photosensitive drum 11 is attached to the apparatus main body 1a. When the drum cartridge 100 is attached to the apparatus main body 1a, the coupling 39 is coupled with a coupling provided on the apparatus main body 1a side, and the driving force is transmitted from the motor provided in the apparatus main body 1a.

[0035] The drum container 30 is also provided with a drum cleaning device 15, which has a cleaning blade 15a, a collection section 15b, and a toner transport screw 38. The cleaning blade 15a is fixed to the drum container 30 and comes into contact with the surface of the photosensitive drum 11 in a counter direction to the rotation direction β of the photosensitive drum 11 during image formation, thereby cleaning the surface of the photosensitive drum 11.

[0036] Furthermore, the recovery unit 15b is provided near the cleaning blade 15a and recovers the transfer residual toner removed by the cleaning blade 15a from the surface of the photosensitive drum 11. A toner transport screw 38 serving as a transport unit transports the toner recovered in the recovery unit 15b to the outside of the drum cartridge 100. The toner transported to the outside of the drum cartridge 100 by the toner transport screw 38 is collected in a waste toner container (not shown) provided in the apparatus main body 1a.

[0037] A gear 36 (FIGS. 3 and 4) is provided as a rotating member fixed to the longitudinal end (end in the direction of the rotation axis) of the photosensitive drum 11 so as to rotate integrally with the photosensitive drum 11 around the rotation axis of the photosensitive drum 11. That is, the gear 36 is provided on the rotation axis of the photosensitive drum 11 so as to rotate together with the photosensitive drum 11. The gear 36 rotates integrally with the photosensitive drum 11 when a driving force is input to the photosensitive drum 11 via a coupling 39. The rotational force of the gear 36 is transmitted to a toner transport screw 38. This rotates the toner transport screw 38, enabling the transfer residual toner collected in the collection section 15b to be transported out of the drum cartridge 100.

[0038] The charging roller 12 as a charging member is a roller-shaped member having a rotating shaft 12a which is a conductive support (core metal, core material) and one or more elastic layers 12b formed around the rotating shaft 12a. The charging roller 12 is brought into contact with the surface of the photosensitive drum 11 with a predetermined pressing force by a pressure spring 32 (FIG. 4) which serves as a first biasing member, and rotates in accordance with the rotation of the photosensitive drum 11.

[0039] A more detailed explanation will be given. The charge roller 12 is rotatably supported by having its rotation shaft 12a held by a charge roller bearing 31 serving as a roller holder. The charge roller bearing 31 is also supported so as to be slidable relative to the drum container 30. Specifically, the charge roller bearing 31 is configured to be slidably guided in a direction toward the rotation axis of the photosensitive drum 11 by a slide guide portion 30c provided on the drum container 30. In the illustrated example, a groove 31a is formed in the charge roller bearing 31 along the sliding direction, and the slide guide portion 30c engages with this groove 31a, thereby guiding the charge roller bearing 31 in a direction toward the rotation axis of the photosensitive drum 11.

[0040] The charging roller 12 supported by the charging roller bearing 31 is movable along a direction toward the rotation axis of the photosensitive drum 11 on a plane perpendicular to the rotation axis of the photosensitive drum 11. As a result, the charging roller 12 is provided so as to be movable between a contact position where it contacts the surface of the photosensitive drum 11 and a spaced position where it is spaced apart from the surface of the photosensitive drum 11. The charging roller 12 charges the surface of the photosensitive drum 11 by applying a voltage at the contact position.

[0041] Furthermore, a pressure spring 32 serving as a first biasing member is provided between the drum container 30 and the charge roller bearing 31. The pressure spring 32 biases the charge roller 12 in a direction toward the rotation axis of the photosensitive drum 11 in a plane perpendicular to the rotation axis of the photosensitive drum 11 (the biasing direction of the pressure spring 32). That is, the pressure spring 32 biases the charge roller bearing 31 in the same direction as the sliding direction of the charge roller bearing 31. Therefore, the charge roller 12 is pressed against the photosensitive drum 11 and comes into contact with it. That is, the pressure spring 32 biases the charge roller 12 in a direction from the separated position toward the contact position.

[0042] The cleaning roller 13 as a cleaning member comes into contact with the charge roller 12 to clean the surface of the charge roller 12. The cleaning roller 13 is a roller-shaped member that has a rotating shaft 13a that is a rod-shaped support portion (core metal, core material) and an elastic layer 13b formed around the rotating shaft 13a, and its outer circumferential surface comes into contact with the charge roller 12. The cleaning roller 13 is brought into contact with the surface of the charge roller 12 with a predetermined pressing force by a pressure spring 34 (FIGS. 3 and 4) that serves as a second biasing member, and rotates in accordance with the rotation of the charge roller 12.

[0043] A more detailed explanation will be given. The cleaning roller 13 is rotatably supported by having its rotation shaft 13a supported by the cleaning roller bearing 33. The cleaning roller bearing 33 is supported slidably relative to the charge roller bearing 31. Specifically, the cleaning roller bearing 33 is configured to be slidable in a direction toward the rotation axis of the charge roller 12 so that the cleaning roller 13 can move along a direction toward the rotation axis of the charge roller 12 in a plane perpendicular to the rotation axis of the charge roller 12. In this embodiment, the rotation axis of the charge roller 12 and the rotation axis of a spacing member 200, which will be described later, are common.

[0044] As a result, the cleaning roller 13 is provided so as to be movable between a roller contact position where it contacts the surface of the charging roller 12 and a roller separation position where it is separated from the surface of the charging roller 12. The cleaning roller 13 cleans the charging roller 12 at the roller contact position.

[0045] Furthermore, a pressure spring 34 serving as a second biasing member is provided between the charge roller bearing 31 and the cleaning roller bearing 33. The pressure spring 34 biases the cleaning roller 13 in a direction (biasing direction) toward the rotational axis of the charge roller 12 in a plane perpendicular to the rotational axis of the charge roller 12. Therefore, the cleaning roller 13 is pressed against the charge roller 12 and comes into contact with it. That is, the pressure spring 34 biases the cleaning roller 13 in a direction from the roller separation position toward the roller contact position. In other words, the cleaning roller 13 is supported by the cleaning roller bearing 33 so as to be movable along the biasing direction of the pressure spring 34. In this embodiment, the biasing direction of the pressure spring 32 and the biasing direction of the pressure spring 34 are substantially the same.

[0046] The cleaning roller 13 is supported by the charging roller bearing 31 via a cleaning roller bearing 33 and a pressure spring 34. Therefore, as will be described below, when the charging roller 12 is moved in a direction away from the photosensitive drum 11 by the spacing member 200, the cleaning roller 13 moves in the direction of movement of the charging roller 12 in conjunction with this.

[0047] With the above configuration, when the photosensitive drum 11 receives a driving force from a driving source such as a motor provided in the apparatus main body 1a and rotates, the charging roller 12 is rotated by the frictional force with the photosensitive drum 11. Furthermore, when the charging roller 12 rotates, the cleaning roller 13 is rotated by the frictional force with the charging roller 12. In addition, the toner transport screw 38 receives a driving force (rotational force) from the gear 36 and rotates.

[0048] [Spacer] Next, the spacing member 200 will be described with reference to Figs. 3 to 7. In Figure 8 5, 6, and 7(a), a separation maintaining configuration in which the photosensitive drum 11 and the charging roller 12, and the charging roller 12 and the cleaning roller 13 are maintained in a separated state by the spacing member 200 will be described.

[0049] [Separation maintenance configuration] The drum cartridge 100 is provided with a spacing member 200 for separating the charging roller 12 from the photosensitive drum 11 and the charging roller 12 from the cleaning roller 13 to ensure clearance during transportation for distribution.

[0050] The spacing member 200 is 12a In this embodiment, the spacing members 200 are provided on both ends of the rotation shaft 12a of the charge roller 12 so as to be able to swing about the rotation shaft 12a as a swing axis. In other words, the spacing members 200 are supported by the charge roller 12 so as to be able to swing about the rotation axis of the charge roller 12. Therefore, the spacing members 200 can move in conjunction with the movement of the charge roller 12. Note that the spacing members 200 on both ends of the charge roller 12 have the same configuration, and therefore will be described below using a diagram showing only one side.

[0051] The spacing member 200 has two spacing retaining portions 210 and 220 and a swing support portion 230. As described above, the swing support portion 230 is swingably fitted to the rotation shaft 12a of the charging roller 12. This allows the spacing member 200 to swing freely relative to the rotation shaft 12a. The spacing retaining portion 210 is disposed between the gear 36 provided on the photosensitive drum 11 and the rotation shaft 12a of the charging roller 12, and separates the photosensitive drum 11 and the charging roller 12 while ensuring a clearance. The spacing retaining portion 220 is disposed between the rotation shaft 12a of the charging roller 12 and the rotation shaft 13a of the cleaning roller 13, and separates the charging roller 12 and the cleaning roller 13 while ensuring a clearance.

[0052] Furthermore, the two separation maintaining portions 210, 220 and the swing support portion 230 are integrally formed. Therefore, when the spacing member 200 is positioned at a first phase in the swing direction, the separation maintaining portions 210, 220 maintain the photosensitive drum 11 and the charging roller 12, and the charging roller 12 and the cleaning roller 13, respectively, in a spaced-apart state (separation maintaining state). On the other hand, when the spacing member 200 swings from the first phase to a second phase in the swing direction, the spaced-apart state between the photosensitive drum 11 and the charging roller 12 and the spaced-apart state between the charging roller 12 and the cleaning roller 13 are simultaneously released (separation released state), as will be described later.

[0053] When the photosensitive drum 11 and the charging roller 12 are in a spaced-apart state, the spacing maintaining portion 210 is sandwiched between the rotation shaft 12a of the charging roller 12 (the rotation shaft of the spacing member 200) and the gear 36 by the pressure (urging force) of the pressure spring 32. When the charging roller 12 and the cleaning roller 13 are in a spaced-apart state, the spacing maintaining portion 220 is sandwiched between the rotation shaft 13a of the cleaning roller 13 and the rotation shaft 12a of the charging roller 12 by the pressure (urging force) of the pressure spring 34.

[0054] As shown in FIG. 7A, the separation maintaining portion 210 of the separation member 200 has an engaging portion 211 that can engage with the gear 36. The engaging portion 211 has gear teeth 211a as engaging protrusions formed on a side surface of the engaging portion 211 that faces the gear 36 of the separation maintaining portion 210 in the separation maintaining state. Furthermore, engaging recesses 36a that can engage with the gear teeth 211a are formed around the entire periphery of the outer circumferential surface of the gear 36. That is, the engaging recesses 36a are formed between the gear teeth of the gear 36. The gear teeth 211a are formed at the same pitch as the pitch of the engaging recesses 36a of the gear 36 (the pitch of the gear teeth of the gear 36). In the separation maintaining state in which the photosensitive drum 11 and the charging roller 12 are separated from each other, the gear teeth 211a of the engaging portion 211 engage with the engaging recesses 36a of the gear 36. The spacing member 200 holds the charging roller 12 in a spaced position where the photosensitive drum 11 and the charging roller 12 are spaced apart against the biasing force of the pressure spring 32, with the engagement portion 211 engaged with the gear 36 as a rotating member.

[0055] The spacing member 200 also has an engaging portion 221 serving as a cleaning member engaging portion that can engage with the rotating shaft 13a of the cleaning roller 13 serving as a part of the cleaning member. The engaging portion 221 is provided on a side surface of the spacing member 220 that faces the rotating shaft 13a in the spacing member state, and is a recess having a radius of curvature that is substantially the same as the outer diameter of the outer peripheral surface of the cylindrical rotating shaft 13a. In the spacing member state in which the charge roller 12 and the cleaning roller 13 are spaced apart, the engaging portion 221 engages with the rotating shaft 13a. In other words, with the engaging portion 221 engaged with the rotating shaft 13a serving as a part of the cleaning member, the spacing member 200 holds the cleaning roller 13 in a spaced position in which the charge roller 12 and the cleaning roller 13 are spaced apart against the biasing force of the pressure spring 34.

[0056] The engaging portion 221 of the spacing maintaining portion 220 is formed to engage with the rotation shaft 13a of the cleaning roller 13 when the engaging portion 211 of the spacing maintaining portion 210 is engaged with the gear 36. Therefore, when the spacing member 200 is positioned in the first phase in the swinging direction, the engaging portion 211 engages with the gear 36, and the engaging portion 221 engages with the rotation shaft 13a. This maintains the charging roller 12 and the cleaning roller 13 in a spaced-apart state. As a result, for example, when the drum cartridge 100 is transported, the elastic layer 12b of the charging roller 12 and the photosensitive drum 11 are spaced apart, and the charging roller 12 and the cleaning roller 13 are also spaced apart, ensuring a clearance between them.

[0057] [Configuration of separation release] 3, 4, and 7(b), a separation release configuration for releasing the separation maintained state between the photosensitive drum 11 and the charging roller 12, and between the charging roller 12 and the cleaning roller 13, using the spacing member 200 will be described. When a new drum cartridge 100 is mounted in the apparatus main body 1a (FIG. 1) and the image forming apparatus 1 (FIG. 1) is started, an initial operation performed by the image forming apparatus 1 inputs a driving force (rotational force) to the photosensitive drum 11 from a motor provided in the apparatus main body 1a.

[0058] When the drum cartridge 100 is installed in the apparatus main body 1a, the photosensitive drum 11 and the charging roller 12, and the charging roller 12 and the cleaning roller 13, are spaced apart, as shown in FIG. 7(a). When the photosensitive drum 11 starts to rotate from this spaced apart state, the gear 36 rotates together with the rotation of the photosensitive drum 11, as shown in FIG. 7(b). Then, the engaging portion 211 engaged with the gear 36 receives the rotational force of the gear 36, and the spacing member 200 swings in the predetermined direction α (the direction of the arrow in FIG. 7(b)).

[0059] By swinging the spacing member 200 in the predetermined direction α in this manner, the engagement portion 211 and the gear 36 are disengaged, and the spacing holding portion 210 is released from being sandwiched between the rotation shaft 12a of the charge roller 12 (the swing shaft of the spacing member 200) and the gear 36. As a result, the state in which the charge roller 12 is held in the separated position is automatically released. In other words, the charge roller 12 comes into contact with the photosensitive drum 11. Note that when the spacing member 200 swings in the direction opposite to the predetermined direction α, the movement of the spacing member 200 is restricted, and the engagement portion 211 and the gear 36 are not disengaged.

[0060] Furthermore, as the spacing member 200 swings in the predetermined direction α, the engagement portion 221 disengages from the rotation shaft 13a of the cleaning roller 13, and the spacing maintaining portion 220 is released from being sandwiched between the rotation shaft 12a of the charge roller 12 and the rotation shaft 13a of the cleaning roller 13. As a result, the cleaning roller 13 is automatically released from being held in the roller separation position. That is, in this embodiment, when the gear 36 rotates due to the initial operation of the image forming apparatus 1 after the drum cartridge 100 is installed in the apparatus main body 1a, the spacing member 200 swings in the predetermined direction α, and the spacing maintaining state between the charge roller 12 and the cleaning roller 13 is automatically released at the same time.

[0061] [Restriction of movement of spaced apart parts] (Reference example) Next, a configuration that can prevent the engagement between the engagement portion 211 of the spacing member 200 and the gear 36 from being inadvertently released even if strong vibrations are applied to the drum cartridge 100, for example, during transportation of the drum cartridge 100, will be described with reference to Figures 8 to 11. Reference example In the example shown in FIG. 1, the regulating portion 300 serving as a regulating means prevents the engagement between the engaging portion 211 of the spacing member 200 and the gear 36 from accidentally coming out of engagement. That is, when the engaging portion 211 is engaged with the gear 36, the regulating portion 300 regulates the spacing member 200 from moving in a direction that increases the distance between the oscillation center of the spacing member 200 and the rotation center of the gear 36 (a direction in which the charge roller bearing 31 is guided along the slide guide portion 30c), so that the engagement between the engaging portion 211 and the gear 36 does not come out of engagement.

[0062] Reference example 8, the regulating portion 300 has an abutting portion 302 provided on the spacing member 200 and an abutted portion 301 provided on the drum container 30. As shown in FIG. 9(a), the abutting portion 302 is provided so as to protrude from the end face of the spacing maintaining portion 210 in the direction of the rotation axis of the photosensitive drum 11. Therefore, the abutting portion 302 is provided outward of the photosensitive drum 11 in the direction of the rotation axis.

[0063] 9(b), the abutted portion 301 is provided on the side wall 30a of the drum container 30 that faces the end of the photosensitive drum 11 in the rotational axis direction. Specifically, the abutted portion 301 is formed by making a portion of the side surface of the side wall 30a that is closer to the charge roller 12 than the portion that faces the end of the photosensitive drum 11 in the rotational axis direction protrude inward (toward the charge roller 12) in the rotational axis direction. The abutted portion 301 is formed so that the abutted portion 302 abuts against the abutted portion 301 when the spacing member 200 moves in a direction that increases the distance between the oscillation center of the spacing member 200 and the rotation center of the gear 36 while the engaging portion 211 is engaged with the gear 36.

[0064] That is, the abutted portion 301 has an abutting surface 301a against which the abutting portion 302 abuts. The abutting surface 301a is formed on the side of the abutting portion 302 when the spacing member 200 is in the spacing-maintaining state, where the distance between the oscillation center of the spacing member 200 and the rotation center of the gear 36 is greater. Here, the spacing member 200 is provided so as to be able to swing freely about the rotation shaft 12a of the charge roller 12, and the oscillation center of the spacing member 200 and the rotation center of the charge roller 12 are substantially the same. In addition, the charge roller 12 is urged toward the photosensitive drum 11 by the pressure spring 32, and the spacing-maintaining portion 210 of the spacing member 200 is sandwiched between the rotation shaft 12a of the charge roller 12 and the gear 36 by the urging force of the pressure spring 32.

[0065] For this reason, Reference example In this case, the side of the spacing member 200 where the distance between the oscillation center of the spacing member 200 (the rotation center of the charging roller 12) and the rotation center of the gear 36 (the rotation center of the photosensitive drum 11) increases is the opposite direction to the biasing direction of the pressure spring 32. Therefore, the abutting surface 301a is located in the opposite direction to the biasing direction of the pressure spring 32 with respect to the abutting portion 302 when the spacing member 200 is in the separation maintaining state. Therefore, when the abutting portion 302 abuts against the abutting surface 301a, the spacing member 200 is restricted from moving in the direction away from the gear 36 against the biasing force of the pressure spring 32.

[0066] Here, as shown in FIGS. 10(a) and 10(b), in the separated and held state, and when the separation member 200 has not moved in the direction in which the distance between the swing center of the separation member 200 and the rotation center of the gear 36 increases, let the distance between the abutting portion 302 and the abutted portion 301 be A. It is preferable that the distance A is greater than 0. That is, it is preferable that there is a gap between the abutting portion 302 and the abutted portion 301 in this state. The separated and held state is a state in which the separation member 200 holds the charging roller 12 at the separated position. Also, the state where the separation member 200 has not moved in the direction in which the distance between the swing center of the separation member 200 and the rotation center of the gear 36 increases means that the separation holding portion 210 of the separation member 200 is pressed against the gear 36 and has not moved away from the gear 36. In this state, the distance A is smaller than the length (engagement amount B) by which the gear tooth 211a and the engagement recess 36a overlap with respect to the protruding direction of the gear tooth 211a when viewed from the rotation direction of the gear 36.

[0067] That is, as shown in FIGS. 10(a) and 10(b), the relationship between the distance A between the abutting portion 302 and the abutting surface 301a in the separated and held state and the engagement amount B between the gear 36 and the engaging portion 211 is such that the distance A is smaller in the sliding direction of the charging roller bearing 31 (the direction in which the charging roller bearing 31 is guided along the slide guide portion 30c). That is, A < B. And with this configuration, when the engaging portion 211 is engaged with the gear 36, the separation member 200 is restricted from moving in the direction in which the distance between the swing center of the separation member 200 and the rotation center of the gear 36 increases so that the engagement between the engaging portion 211 and the gear 36 does not disengage.

[0068] For example, due to vibrations or drops during the transportation of the drum cartridge 100, the charging roller 12 may move in a direction away from the photosensitive drum 11 against the biasing force of the pressure spring 32. In this case, the separation member 200 supported on the rotation shaft of the charging roller 12 also moves in a direction away from the photosensitive drum 11. However, since the distance A is smaller than the engagement amount B as described above, before the engagement between the engaging portion 211 and the gear 36 disengages, the abutting portion 302 abuts against the abutted portion 301, restricting the movement of the separation member 200 and suppressing the release of the separated and held state.

[0069] When the separation state is released, the gear 36 rotates together with the photosensitive drum 11, causing the spacing member 200 to swing, thereby releasing the engagement between the engaging portion 211 and the gear 36. At this time, the spacing member 200 is biased toward the photosensitive drum 11 together with the charging roller 12 by the pressure spring 32, and therefore moves toward the photosensitive drum 11 as the engagement between the engaging portion 211 and the gear 36 is released. In other words, while the spacing member 200 swings, the abutting portion 302 provided on the spacing member 200 moves in a direction away from the abutted portion 301. Therefore, the abutting portion 302 does not interfere with the abutted portion 301, and the spacing member 200 swings, releasing the separation state.

[0070] Also, Reference example In this case, when the abutting portion 302 abuts against the abutted portion 301, the spacing member 200 is restricted from rotating in the opposite direction to the rotation direction (predetermined direction α) in which the spacing member 200 is automatically released from the position in the separation-maintaining state. For this reason, as shown in Fig. 11(a), the abutted portion 301 is formed so that when it abuts against the abutting portion 302, a resistance force P in the normal direction acting on the abutting portion 302 acts in a direction that causes the spacing member 200 to swing in the opposite direction to the predetermined direction α.

[0071] Reference example 11(b), the abutting surface 301a of the abutted portion 301 is inclined in the direction opposite to the predetermined direction α with respect to the direction perpendicular to the biasing direction S of the pressure spring 32 (e.g., FIG. 9(a)). In other words, the abutting surface 301a is configured as a surface inclined with respect to the sliding direction of the charge roller bearing 31.

[0072] A more specific explanation will be given below. The abutting surface 301a is an inclined surface such that, when it comes into contact with the abutting portion 302, a reaction force P in the normal direction exerted on the abutting portion 302 has a force component that rotates the spacing member 200 in the direction opposite to the direction in which the spacing member 200 rotates during automatic release (predetermined direction α). In other words, as shown in Fig. 11(a), the reaction force P in the normal direction generates a torque T that rotates the spacing member 200 in the direction opposite to the predetermined direction α.

[0073] Reference example 11(b), the normal direction N of the abutment surface 301a is oriented toward the cleaning blade 15a side in the sliding direction of the charging roller bearing 31, rather than the direction toward the rotation axis of the photosensitive drum 11 (i.e., the biasing direction S). As shown in FIG. 2, the cleaning blade 15a abuts against the photosensitive drum 11 in the counter direction to the rotation direction of the photosensitive drum 11. Also, in order to clean the surface of the photosensitive drum 11 before charging the photosensitive drum 11, the cleaning blade 15a is disposed upstream of the charging roller 12 with respect to the rotation direction of the photosensitive drum 11. The spacing member 200 oscillates in a predetermined direction α when the photosensitive drum 11 rotates in the rotation direction β. Therefore, the cleaning blade 15a is positioned in the opposite direction to the predetermined direction α with respect to the spacing member 200. Therefore, Reference example In this example, the normal direction N of the abutting surface 301a is oriented closer to the cleaning blade 15a than the biasing direction S.

[0074] If a large impact is applied to the drum cartridge 100 during transportation, the following problem may occur: The relationship between the distance A between the abutting portion 302 and the abutting surface 301a in the separated state and the engagement amount B between the gear 36 and the engaging portion 211 may be reversed due to deformation of the drum container 30, i.e., A>B.

[0075] However, by inclining the abutting surface 301a as described above, it is possible to prevent the separation state from being inadvertently released even if, for example, A > B and the gear 36 and the engaging portion 211 are temporarily separated. That is, when the spacing member 200 moves due to an impact and the abutting portion 302 comes into contact with the abutting surface 301a, a normal resistance P is generated in the abutting portion 302 such that the spacing member 200 rotates in the opposite direction to the direction (predetermined direction α) in which the spacing member 200 rotates during automatic release. Therefore, the spacing member 200 is prevented from rotating in the predetermined direction α, and it is possible to prevent the separation state from being released even if A > B.

[0076] (Example of the present invention) The feature of the present invention is that in addition to this configuration (a configuration in which the spacing member 200 is provided with an abutting portion 302, and the abutting portion 302 of the spacing member 200 abuts against the abutted portion 301 of the drum container 30), a configuration is further provided to prevent the separation state from being released. Note that even if the spacing member 200 is not provided with the abutting portion 302, a modified example may be used in which the spacing member 200 has a configuration to be described later and thereby can prevent the separation state from being released. In this embodiment, as shown in FIG. 13, the spacing member 200 is provided with a charging roller 12 The supported portion 212 is supported by the core metal. 212 From the charging roller 12 The supported portion extends along the core metal of 212 and engagement part 211 and a connecting portion 213 (extension portion) that connects the above. 213 If the length is long, the connecting part 213 is the supported part 212 The photoconductor unit is prone to bending starting from this point. 100 When an external force is applied to the engaging part 211 Gear 36 The connecting part moves away from 213 As a result, the engaging portion 211 and gear 36To prevent this, in the separation-maintaining state, the charging roller bearing is disposed on the surface (opposite surface) of the separation-maintaining part 210 opposite to the gear 36 in the biasing direction of the pressure spring 32 (first biasing member). 31 The protrusion 310 is configured to abut against the charging roller bearing. 31 In this embodiment, the protrusion 310 is configured as a part of the charging roller bearing. 31 However, the shape is not limited to a protruding shape, and the charging roller bearing 31 The spacing maintaining portion 210 does not have to be configured so that a portion of the spacing maintaining portion 210 protrudes from the gear 36, as long as it abuts against the spacing maintaining portion 210. This configuration makes it possible to prevent the spacing maintaining portion 210 from separating from the gear 36 when the spacing maintaining portion 210 is momentarily deformed when vibrations or impacts are applied to the drum cartridge 100. This configuration makes it possible to prevent the spacing maintaining portion 210 from separating from the gear 36 when vibrations or impacts are applied to the drum cartridge 100, even if the spacing maintaining portion 210 has low rigidity.

[0077] Here, the configuration of the protrusion 311 is shown in FIG. 12 ,figure 13 This will be explained using the figure. 12 is a perspective view of the drum cartridge 100. The protrusion 311 constitutes part of the charge roller bearing 31, and is therefore provided outside the charge roller 12b in the direction of the rotation axis of the charge roller 12b. In other words, the protrusion 311 is molded integrally with the charge roller bearing 31. 13 1 is a diagram showing the relationship between the protrusion 311 and the separation maintaining portion 210 in the separation maintaining state. 36 is engaged with the charging roller 12b is photosensitive Drum 11When the engaging portion 211 is spaced apart from the gear 36 (spaced state), the protrusion 311 is in contact with the space maintaining portion 210. The configuration in which the protrusion 311 presses the space maintaining portion 210 with the biasing force of the pressure spring 32 makes it possible to prevent disengagement even if a force is applied to the engaging portion 211 in a direction away from the gear 36 when a shock is applied. Meanwhile, in this embodiment, the portion of the protrusion 311 that comes into contact with the space maintaining portion 210 has an arc shape. The part of the protrusion 311 that comes into contact with the spacing retainer 210 is The arc shape reduces the contact area between the protrusion 311 and the spacing maintaining portion 210 when the spacing maintaining member 200 rotates, thereby reducing the load that the protrusion 311 places on the rotation of the spacing maintaining portion 210. Furthermore, it is preferable that at least a portion of the protrusion 311 overlaps with the engaging portion 211 in the direction of the rotation axis of the charge roller 12. This configuration prevents the engaging portion 211 from separating from the gear 36. In this embodiment, the distance A is shorter than the distance B.

[0078] In this embodiment, the engagement portion 211 and gear 36 is engaged with the charging roller 12b is photosensitive Drum 11 In the previous configuration, when the engaging portion 211 is spaced apart from the gear 36 (separated state), the protrusion 311 is disposed in contact with the separation maintaining portion 210. As an alternative configuration, the following configuration is also possible. That is, in the separated state, the protrusion 311 is disposed at a distance C (shortest distance) from the separation maintaining portion 210. The distance C is shorter than the distance B (amount of engagement between the engaging portion 211 and the gear 36) described above. With this configuration, even if, upon receiving a shock, the engaging portion 211 receives a force in a direction away from the gear 36 and moves in the direction away from the gear 36, the separation maintaining portion 210 can be prevented from coming into contact with the protrusion 311 and thereby being disengaged. The distance C is also shorter than the distance B. Even with such a configuration, it is possible to obtain an effect equivalent to that of the above configuration.

[0079] In this embodiment, the protrusion 311 has an arc shape, but is not limited to this shape and may have another configuration in which the width becomes smaller as it approaches the photosensitive drum 11.

[0080] (Modification of the present invention) In this embodiment, the regulating portion is a plate-shaped protrusion protruding from the side wall 30a of the drum container 30, but as shown in Figures 14 and 15, the side wall 30d of the drum container 30 may also serve as the regulating portion. That is, as shown in Figures 14 and 15, the end surface 31b of the charge roller bearing 31 serves as the abutting portion 302, and the side wall 30d of the drum container 30 serves as the abutted portion 301. When the engaging portion 211 is engaged with the gear 36 (the separation holding state in Figure 15), and the spacing member 200 moves in a direction in which the distance between the oscillation center of the spacing member 200 and the rotation center of the gear 36 increases (the direction in which the charge roller bearing 31 is guided along the slide guide portion 30c), the abutting portion 302 (the end surface 31b of the charge roller bearing 31) abuts against the abutted portion 301 (the side wall 30d of the drum container 30). Even with this configuration, it is desirable that the engagement amount B (the length over which the engagement portion 211 is engaged with the gear 36) between the gear 36 and the engagement portion 211 in FIG. 14 is greater than the distance A (shortest distance) between the abutting portion 302 (end surface 31b of the charging roller bearing 31) and the abutted portion 301 (side wall 30d of the drum container 30) in the separated state of FIG. 15.

[0081] As described above, even when vibration or impact is applied to the drum cartridge 100, causing a force to move the separation maintaining portion 210 in a direction away from the gear 36, it is possible to prevent the engagement between the engaging portion 211 and the gear 36 from being disengaged. As a result, it is possible to reduce the possibility of the separation maintaining state between the photosensitive drum 11 and the charging roller 12, and further between the charging roller 12 and the cleaning roller 13, being unintentionally released. [Explanation of symbols]

[0082] 1. Image forming device 1a Device body 11 Photosensitive drum (photoconductor) 12 Charging roller 12a Rotation axis 13 Cleaning roller (cleaning material) 13a Rotating shaft (part of cleaning member) 30 Drum container (frame) 30a, 30d side wall 30b Connecting part 30c Slide guide 31, 31A Charge roller bearing (roller holding part) 32 pressure spring (first biasing member) 34 Pressure spring (second biasing member) 36 Gear (rotating part) 36a Engagement recess 100 drum cartridges (photosensitive units) 200, 200A spacing member 210 Separation holding part 211 Engagement part 211a gear teeth (engaging protrusions) 220 Separation holding part 221 Engagement portion (cleaning member engagement portion) 300, 300A Regulatory Section 301, 301A Abutted part 301a, 301Aa butting surface 302, 302A butt section

Claims

1. A photosensitive unit that can be attached to an image forming apparatus, a rotatable photoreceptor; a rotatable charging roller that contacts the photoreceptor and charges the photoreceptor; a charging roller bearing member attached to a rotation shaft of the charging roller and rotatably supporting the charging roller; a biasing member provided on the charging roller bearing member and biasing the charging roller toward the photosensitive member; a gear provided at a first end of the photosensitive member in a rotational axis direction; a spacing member provided on a rotation shaft of the charging roller, the spacing member having an engaging portion that engages with the gear, for spacing the charging roller and the photosensitive member apart; a guide portion that guides the charge roller bearing member urged by the urging member so that the charge roller separates from the photosensitive body when the engagement portion and the gear are engaged, and that guides the charge roller bearing member urged by the urging member so that the charge roller contacts the photosensitive body when the engagement portion and the gear are not engaged; a frame including a first side wall disposed at a first end of the photosensitive member in a rotational axis direction, a second side wall disposed at a second end of the photosensitive member in the rotational axis direction, and a connecting portion connecting the first side wall and the second side wall, the frame rotatably supporting the photosensitive member on the first side wall and the second side wall; Equipped with When the shortest distance between the end surface of the charge roller bearing member urged by the urging member and the first side wall in a state in which the engaging portion and the gear are engaged is A, and the amount of engagement between the engaging portion and the gear in a state in which the engaging portion and the gear are engaged is B, A photoreceptor unit characterized in that A<B is satisfied.

2. a rotatable cleaning roller that contacts the charging roller to clean the charging roller; a cleaning roller bearing member attached to a rotation shaft of the cleaning roller and rotatably supporting the cleaning roller; a second biasing member provided on the cleaning roller bearing member for biasing the cleaning roller toward the charging roller; a second guide portion that guides the cleaning roller bearing member biased by the second biasing member so that the cleaning roller separates from the charging roller when the engagement portion and the gear are engaged, and that guides the cleaning roller bearing member biased by the second biasing member so that the cleaning roller contacts the charging roller when the engagement portion and the gear are not engaged; The photoreceptor unit according to claim 1 , further comprising:

3. a driving force receiving portion for receiving a driving force for rotating the photosensitive member; In a state in which the engaging portion and the gear are engaged with each other, as the driving force receiving portion receives the driving force and the gear rotates, the state in which the engaging portion and the gear are engaged with each other transitions to a state in which the engaging portion and the gear are not engaged with each other.

3. The photosensitive unit according to claim 1, wherein the photosensitive member is a photosensitive member.

Images