Patent Publication Number: US-10761447-B2

Title: Photosensitive unit

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a photosensitive unit including a photosensitive member. 
     Description of the Related Art 
     A configuration that a photosensitive unit in which parts such as a photosensitive member, for example, a photosensitive drum, and a charging roller that charges the surface of the photosensitive member are unitized is attachable to and detachable from an apparatus body of an image forming apparatus is conventionally known. In the case of a system in which a photosensitive member is charged by bringing a charging roller into contact with the photosensitive member, the charging roller is deformed when the charging roller is left in contact with the photosensitive member for a long period. Therefore, a configuration in which the photosensitive member is separated from the charging roller until the photosensitive unit is attached to the apparatus body is also conventionally known. 
     For example, Japanese Patent Laid-Open No. 2012-18265 proposes a configuration in which a separation member that separates a charging roller from a photosensitive member against an urging force urging the charging roller toward the photosensitive member is disposed between the photosensitive member and the charging roller. The configuration disclosed in Japanese Patent Laid-Open No. 2012-18265 includes a gear serving as a rotary member that rotates together with the photosensitive member, and the photosensitive member and the charging roller are separated from each other by engaging an engagement portion of the separation member with the gear. Further, the separation state of the charging roller and the photosensitive member by the separation member is cancelled by releasing the engagement between the gear and the separation member by rotating the gear together with the photosensitive member. 
     There is a case where a vibration is applied to the photosensitive unit during transportation of the photosensitive unit, and thus the separation member is moved to release the engagement between the separation member and the gear. Therefore, in the configuration disclosed in Japanese Patent Laid-Open No. 2012-18265, the separation member includes a concave portion, and in the separation state, movement of the separation member caused by the vibration is suppressed by causing the concave portion to abut a photosensitive drum serving as the photosensitive member. 
     However, in the case of the configuration disclosed in Japanese Patent Laid-Open No. 2012-18265, there is a risk that, in the case where a strong vibration is applied to the photosensitive unit and the separation member is moved in a direction away from the gear, the engagement between the engagement portion of the separation member and the gear is released and cancellation of the separation state of the photosensitive member and the charging roller cannot be prevented. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the invention, a photosensitive unit includes a rotatable photosensitive member, a frame configured to hold the photosensitive member, a charging roller provided to be movable between a contact position and a separation position and configured to charge a surface of the photosensitive member by being subjected to application of a voltage at the contact position, the charging roller being in contact with the surface of the photosensitive member at the contact position and being separated from the surface of the photosensitive member at the separation position, an urging portion configured to urge the charging roller in a direction from the separation position toward the contact position, a rotary member configured to rotate by receiving input of a driving force, a separation member including an engagement portion capable of engaging with the rotary member, wherein the separation member is configured to hold the charging roller at the separation position against an urging force of the urging portion in a state in which the engagement portion is engaged with the rotary member, and, in a case where the rotary member rotates, the separation member swings in accordance with rotation of the rotary member, engagement between the engagement portion and the rotary member is released, and a state in which the charging roller is held at the separation position is cancelled, an abutting portion provided on the separation member, and an abutted portion that is provided on the frame and that the abutting portion abuts in a case where the separation member moves in a direction to increase a distance between a swing center of the separation member and a rotation center of the rotary member in a state in which the engagement portion is engaged with the rotary member. 
     According to a second aspect to the invention, a photosensitive unit includes a rotatable photosensitive member, a charging roller provided to be movable between a contact position and a separation position and configured to charge a surface of the photosensitive member by being subjected to application of a voltage at the contact position, the charging roller being in contact with the surface of the photosensitive member at the contact position and being separated from the surface of the photosensitive member at the separation position, an urging portion configured to urge the charging roller in a direction from the separation position toward the contact position, a rotary member configured to rotate by receiving input of a driving force, a separation member including an engagement portion capable of engaging with the rotary member, wherein the separation member is configured to hold the charging roller at the separation position against an urging force of the urging portion in a state in which the engagement portion is engaged with the rotary member, and, in a case where the rotary member rotates, the separation member moves in accordance with rotation of the rotary member, engagement between the engagement portion and the rotary member is released, and a state in which the charging roller is held at the separation position is cancelled, and a regulation portion configured to, in a state in which the engagement portion is engaged with the rotary member, regulate movement of the separation member in such a direction that the separation member moves away from a rotation center of the rotary member in a radial direction of the rotary member, such that the engagement between the engagement portion and the rotary member is not released. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic section view of an image forming apparatus according to a first exemplary embodiment illustrating a configuration thereof. 
         FIG. 2  is a schematic section view of a drum unit according to the first exemplary embodiment illustrating a configuration thereof. 
         FIG. 3  is a partial perspective view of the drum unit according to the first exemplary embodiment which illustrates a contact state thereof and in which a regulation portion is omitted. 
         FIG. 4  is a partial perspective view of the drum unit according to the first exemplary embodiment which illustrates the contact state thereof and in which the regulation portion, a separation member, and a frame are omitted. 
         FIG. 5  is a partial perspective view of the drum unit according to the first exemplary embodiment which illustrates a separation state thereof and in which the regulation portion is omitted. 
         FIG. 6  is a partial perspective view of the drum unit according to the first exemplary embodiment which illustrates the separation state thereof and in which the regulation portion and the frame are omitted. 
         FIG. 7A  is a schematic section view of the separation member according to the first exemplary embodiment illustrating the separation state thereof. 
         FIG. 7B  is a schematic section view of the separation member according to the first exemplary embodiment illustrating a state in which the separation state thereof is cancelled. 
         FIG. 8  is a partial perspective view of the drum unit according to the first exemplary embodiment illustrating the separation state thereof. 
         FIG. 9A  is a partial perspective view of the drum unit according to the first exemplary embodiment which illustrates the separation state thereof and in which the frame is omitted. 
         FIG. 9B  is a partial perspective view of a photosensitive drum and the frame of the drum unit according to the first exemplary embodiment. 
         FIG. 10A  is a partial side view of the drum unit according to the first exemplary embodiment illustrating the separation state thereof. 
         FIG. 10B  is a section view of the drum unit according to the first exemplary embodiment taken along a line X-X of  FIG. 10A . 
         FIG. 11A  is a diagram similar to  FIG. 10B  illustrating a direction of a torque acting when an abutting portion abuts an abutted portion in the first exemplary embodiment. 
         FIG. 11B  is a diagram similar to  FIG. 10B  illustrating a relationship between an urging direction in which an urging force is applied to the separation member when the abutting portion abuts the abutted portion in the first exemplary embodiment and a normal vector at the abutting portion. 
         FIG. 12  is a partial perspective view of a drum unit according to a second exemplary embodiment illustrating a separation state thereof. 
         FIG. 13A  is a partial perspective view of the drum unit according to the second exemplary embodiment which illustrates the separation state thereof and in which a frame is omitted. 
         FIG. 13B  is a partial perspective view of a photosensitive drum and the frame of the drum unit according to the second exemplary embodiment. 
         FIG. 14A  is a partial side view of the drum unit according to the second exemplary embodiment illustrating the separation state thereof. 
         FIG. 14B  is a section view of the drum unit according to the second exemplary embodiment taken along a line Y-Y of  FIG. 14A . 
         FIG. 15A  is a partial side view of the drum unit according to the second exemplary embodiment illustrating the separation state thereof. 
         FIG. 15B  is a section view of the drum unit according to the second exemplary embodiment taken along a line Z-Z of  FIG. 15A . 
         FIG. 16A  is a diagram similar to  FIG. 15B  illustrating a direction of a torque acting when an abutting portion abuts an abutted portion in the second exemplary embodiment. 
         FIG. 16B  is a diagram similar to  FIG. 15B  illustrating a relationship between an urging direction in which an urging force is applied to a separation member when the abutting portion abuts the abutted portion in the second exemplary embodiment and a normal vector at the abutting portion. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     First Exemplary Embodiment 
     A first exemplary embodiment of the present invention will be described with reference to  FIGS. 1 to 11B . First, a schematic configuration of an image forming apparatus of the present exemplary embodiment will be described with reference to  FIG. 1 . 
     Image Forming Apparatus 
     An image forming apparatus  1  is an image forming apparatus of a tandem type which is capable of forming a full-color image using an electrophotographic system and in which an intermediate transfer system is employed. That is, the image forming apparatus  1  includes image forming portions  10  of respective colors of Y, M, C, and K, and has a so-called tandem type configuration in which these image forming portions  10  of respective colors are arranged in a rotation direction of an intermediate transfer belt  61 . Y, M, C, and K respectively represent yellow, magenta, cyan, and black. The configurations and operations of the image forming portions  10  are substantially the same except that the colors of used toners are different. 
     The image forming portions  10  each include a photosensitive drum  11  that is an electrophotographic photosensitive member having a cylindrical shape. The photosensitive drum  11  receives a driving force transmitted from an unillustrated driving portion provided in an apparatus body  1   a , and is thus rotationally driven at a process speed of 100 mm/sec, which is a peripheral speed. In each of the image forming portion  10 , a charging roller  12 , a developing unit  14 , a primary transfer roller  17 , and a drum cleaning unit  15  are arranged in the vicinity of the photosensitive drum  11  in this order along a rotation direction of the photosensitive drum  11 . An exposing unit  16  is disposed below the image forming portions  10 . In addition, the image forming apparatus  1  includes the intermediate transfer belt  61  provided so as to be in contact with the photosensitive drums  11  of the image forming portions  10  and formed as an endless belt body serving as an intermediate transfer member. 
     The charging roller  12  serving as a charging member is a rotatable roller-shaped charging member, is disposed to be in contact with the photosensitive drum  11 , and charges the surface of the photosensitive drum  11 . The exposing unit  16  serving as an exposing portion exposes the charged surface of the photosensitive drum  11  to form an electrostatic latent image on the photosensitive drum  11 . The exposing unit  16  is a laser scanner unit in the present exemplary embodiment. 
     The developing unit  14  accommodates toner serving as developer therein, and develops, as a toner image and by using the toner, the electrostatic latent image formed on the photosensitive drum  11 . The developing unit  14  having such a configuration includes a developing sleeve  14   a  serving as a developer bearing member that bears the toner and conveys the toner to an opposing portion, that is, a developing position of the photosensitive drum  11 . The developing sleeve  14   a  is rotationally driven. 
     The primary transfer roller  17  is a roller-shaped primary transfer member, and transfers the toner image formed on the photosensitive drum  11  onto the intermediate transfer belt  61  through primary transfer. The drum cleaning unit  15  cleans transfer residual toner and the like remaining on the photosensitive drum  11  after the primary transfer. 
     The intermediate transfer belt  61  is formed as an endless belt from a dielectric resin such as polyimide. The intermediate transfer belt  61  is stretched over a plurality of support rollers serving as stretching rollers by a predetermined tension. The primary transfer rollers  17  described above are disposed at positions opposing the respective photosensitive drums  11  on the inner peripheral surface side, that is, the back surface side of the intermediate transfer belt  61 . The primary transfer rollers  17  are pressed against the photosensitive drums  11  with the intermediate transfer belt  61  therebetween, and form primary transfer portions N 1 , that is, primary transfer nip portions N 1 , where the intermediate transfer belt  61  is in contact with the photosensitive drums  11 . The primary transfer rollers  17  are rotationally driven in accordance with the rotation of the intermediate transfer belt  61 . 
     In addition, a secondary transfer roller  35  serving as a roller-shaped secondary transfer member is disposed on the outer peripheral surface side, that is, the front surface side of the intermediate transfer belt  61  at a position opposing a secondary transfer opposing roller  62 . The secondary transfer roller  35  is pressed against the secondary transfer opposing roller  62  with the intermediate transfer belt  61  therebetween, and forms a secondary transfer portion N 2 , that is, secondary transfer nip portion N 2 , where the intermediate transfer belt  61  and the secondary transfer roller  35  are in contact with each other. The toner images transferred onto the intermediate transfer belt  61  are transferred onto a recording material P through secondary transfer at the secondary transfer portion N 2 . 
     In addition, a belt cleaning unit  70  serving as an intermediate transfer member cleaning portion is disposed on the outer peripheral surface side of the intermediate transfer belt  61  at a position opposing a tension roller  64 . The belt cleaning unit  70  cleans transfer residual toner and the like remaining on the intermediate transfer belt  61  after secondary transfer. 
     Next, an image forming operation will be described. At the time of image formation, the surface of the photosensitive drum  11  that is rotationally driven is uniformly charged to a predetermined potential of a predetermined polarity by the charging roller  12 . In the present exemplary embodiment, only a direct current voltage of −1300 V is applied to the charging roller  12  from an unillustrated high-voltage power source serving as a charging power source, thus electrical discharge to the surface of the photosensitive drum  11  occurs, and the surface of the photosensitive drum  11  is charged to about −700V. 
     After the surface of the photosensitive drum  11  is uniformly charged, the surface of the photosensitive drum  11  is scanned and exposed by the exposing unit  16  in accordance with a signal of image information, and an electrostatic latent image, that is, an electrostatic image is formed on the surface of the photosensitive drum  11 . To be noted, the image forming apparatus  1  of the present exemplary embodiment includes an image reading apparatus  2 , and examples of the image information include image information of a document read by the image reading apparatus  2  and image information transmitted from an external terminal such as a personal computer connected to the image forming apparatus  1 . 
     The electrostatic latent image formed on the photosensitive drum  11  is developed as a toner image by the developing unit  14  by using the toner serving as developer. In the present exemplary embodiment, the normal charging polarity of the toner is a negative polarity. At the time of development, a predetermined developing voltage serving as a developing bias is applied to the developing sleeve  14   a  from an unillustrated high-voltage power source serving as a developing power source. As the developing voltage, an oscillatory voltage in which a direct current voltage serving as a direct current component and an alternate current voltage serving as an alternate current component are superimposed on each other is used. In addition, the toner is supplied to the developing unit  14  from a toner bottle  19  serving as a toner container through an unillustrated toner conveyance path. 
     The toner image formed on the photosensitive drum  11  is transferred onto the surface of the intermediate transfer belt  61  through primary transfer at the primary transfer portion N 1  by an action of the primary transfer roller  17 . At this time, a primary transfer voltage serving as a primary transfer bias that is a direct current voltage of a polarity opposite to the charging polarity of the toner at the time of development is applied to the primary transfer roller  17  from an unillustrated primary transfer power source that is a high-voltage power source. In the present exemplary embodiment, the polarity of the primary transfer voltage is a positive polarity. When forming a full-color image, the operation described above is performed in each of the image forming portions  10 , and toner images of yellow, magenta, cyan, and black formed on the respective photosensitive drums  11  are sequentially transferred onto the intermediate transfer belt  61  so as to be superimposed on one another. After the transfer, transfer residual toner of a small amount remaining on the photosensitive drums  11  is removed by the drum cleaning units  15  and collected by collecting portions. 
     Meanwhile, recording materials P are fed one by one from a feeding cassette  20 , and conveyed to a registration roller pair  23 . Each recording material P is, for example, a sheet such as a paper sheet or a plastic sheet. Then, the registration roller pair  23  conveys the recording material P to the nip between the intermediate transfer belt  61  and the secondary transfer roller  35  at a timing matching conveyance of a toner image on the intermediate transfer belt  61 . 
     The color toner image on the intermediate transfer belt  61  is transferred onto the surface of the recording material P through secondary transfer at the secondary transfer portion N 2  by an action of the secondary transfer roller  35 . When the recording material P passes through the secondary transfer portion N 2 , a secondary transfer voltage serving as a secondary transfer bias that is a direct current voltage of a polarity opposite to the charging polarity of the toner at the time of development is applied to the secondary transfer roller  35  from an unillustrated secondary transfer power source that is a high-voltage power source. After the transfer, transfer residual toner of a small amount remaining on the intermediate transfer belt  61  is removed and collected by the belt cleaning unit  70  to prepare for the next image formation. 
     The toner image transferred onto the recording material P is fixed by being heated and pressurized in a nip portion formed by a heating roller  41  and a pressurizing roller  42  of a fixing unit  40 , and the recording material P is discharged onto a discharge tray  51  by a discharge roller pair  50 . 
     Drum Cartridge 
     Next, a schematic configuration of a drum cartridge  100  serving as a photosensitive unit will be described with reference to  FIGS. 2 to 4 . In the present exemplary embodiment, the drum cartridge  100  including the photosensitive drum  11  is configured to be attachable to and detachable from the apparatus body  1   a  illustrated in  FIG. 1  such that the drum cartridge  100  including the photosensitive drum  11  can be replaced in maintenance or the like. For example, the drum cartridge  100  is configured to be attachable to and detachable from the apparatus body  1   a  by moving the drum cartridge  100  in a longitudinal direction of the apparatus body  1   a , that is, in a rotation axis direction of the photosensitive drum  11 . 
     As illustrated in  FIG. 2 , the drum cartridge  100  includes the photosensitive drum  11  serving as a photosensitive member, the charging roller  12 , the cleaning roller  13  serving as a cleaning member, the drum cleaning unit  15 , a separation member  200 , and so forth. These are held in an integrated manner by a drum container  30  serving as a frame. 
     In the drum container  30 , the photosensitive drum  11  is held via an unillustrated bearing so as to be rotatable around a rotation axis thereof. That is, as illustrated in  FIG. 3 , the drum container  30  includes side walls  30   a  disposed on both sides of rotation axes of the photosensitive drum  11 , the charging roller  12 , and the cleaning roller  13 , and a connecting portion  30   b  interconnecting the side walls  30   a . Further, both end portions of the photosensitive drum  11  in the rotation axis direction thereof are rotatably held by the respective side walls  30   a  on both sides in the rotation axis direction via bearings. 
     In addition, a coupling  39  illustrated in  FIG. 4  for receiving a driving force from an unillustrated motor serving as a drive source and provided in the apparatus body  1   a  to rotate in a state of being attached to the apparatus body  1   a  is provided on the photosensitive drum  11 . When the drum cartridge  100  is attached to the apparatus body  1   a , the coupling  39  is coupled to a coupling provided on the apparatus body  1   a  and receives the driving force transmitted from the motor provided in the apparatus body  1   a.    
     In addition, the drum container  30  includes the drum cleaning unit  15 , and the drum cleaning unit  15  includes a cleaning blade  15   a , a collection portion  15   b , and a toner conveyance screw  38 . The cleaning blade  15   a  is fixed to the drum container  30 , abuts the surface of the photosensitive drum  11  in a counter direction with respect to a rotation direction β in which the photosensitive drum  11  rotates during image formation, and thus cleans the surface of the photosensitive drum  11 . 
     In addition, the collection portion  15   b  is provided in the vicinity of the cleaning blade  15   a , and collects transfer residual toner removed from the surface of the photosensitive drum  11  by the cleaning blade  15   a . The toner conveyance screw  38  serving as a conveyance portion conveys the toner collected by the collection portion  15   b  to the outside of the drum cartridge  100 . The toner conveyed to the outside of the drum cartridge  100  by the toner conveyance screw  38  is collected in an unillustrated waste toner container provided in the apparatus body  1   a.    
     A gear  36  illustrated in  FIGS. 3 and 4  serving as a rotary member fixed to integrally rotate with the photosensitive drum  11  about the rotation axis of the photosensitive drum  11  is provided on an end portion of the photosensitive drum  11  in the longitudinal direction, that is, in the rotation axis direction. That is, the gear  36  is provided on a rotation shaft of the photosensitive drum  11  so as to rotate together with the photosensitive drum  11 . The gear  36  integrally rotates with the photosensitive drum  11  when a driving force is input to the photosensitive drum  11  via the coupling  39 . The rotational force of the gear  36  is transmitted to the toner conveyance screw  38 . As a result of this, the toner conveyance screw  38  rotates, and the transfer residual toner collected by the collection portion  15   b  is conveyed to the outside of the drum cartridge  100 . 
     The charging roller  12  serving as a charging member is a roller-shaped member including a rotation shaft  12   a  that is a conductive support body such as a core metal or core material, and at least one elastic layer  12   b  formed around the rotation shaft  12   a . The charging roller  12  is pressed to be in contact with the surface of the photosensitive drum  11  by a predetermined pressing force by a pressurizing spring  32  illustrated in  FIG. 4  serving as an urging portion, and is rotationally driven in accordance with the rotation of the photosensitive drum  11 . 
     More specific description will be given below. The rotation shaft  12   a  of the charging roller  12  is held by a charging roller bearing  31  serving as a roller holding portion, and thus the charging roller  12  is rotatably supported. In addition, the charging roller bearing  31  is slidably supported with respect to the drum container  30 . Specifically, the charging roller bearing  31  is configured to be guided to be slidable in a direction toward the rotation axis of the photosensitive drum  11  by a slide guiding portion  30   c  provided in the drum container  30 . In the illustrated example, a groove  31   a  is defined in the charging roller bearing  31  along the sliding direction thereof, and the slide guiding portion  30   c  engages with the groove  31   a  to guide the charging roller bearing  31  in the direction toward the rotation axis of the photosensitive drum  11 . 
     Further, the charging roller  12  supported by the charging roller bearing  31  is configured to be movable in the direction toward the rotation axis of the photosensitive drum  11  along a plane perpendicular to the rotation axis of the photosensitive drum  11 . As a result of this, the charging roller  12  is configured to be movable between a contact position where the charging roller  12  is in contact with the surface of the photosensitive drum  11  and a separation position where the charging roller  12  is separated from the surface of the photosensitive drum  11 . Further, at the contact position, a voltage is applied to the charging roller  12 , and thus the charging roller  12  charges the surface of the photosensitive drum  11 . 
     Further, the pressurizing spring  32  serving as an urging portion is provided between the drum container  30  and the charging roller bearing  31 . The pressurizing spring  32  urges the charging roller  12  in the direction toward the rotation axis of the photosensitive drum  11  along the plane perpendicular to the rotation axis of the photosensitive drum  11 . This direction serves as an urging direction. That is, the pressurizing spring  32  urges the charging roller bearing  31  in the same direction as the sliding direction of the charging roller bearing  31 . Therefore, the charging roller  12  is brought into pressure contact with the photosensitive drum  11 . That is, the pressurizing spring  32  urges the charging roller  12  in a direction from the separation position toward the contact position. 
     The cleaning roller  13  serving as a cleaning member comes into contact with the charging roller  12  and cleans the surface of the charging roller  12 . The cleaning roller  13  is a roller-shaped member including a rotation shaft  13   a  that is a rod-shaped supporting portion such as a core metal or a core material, and an elastic layer  13   b  formed around the rotation shaft  13   a , and the outer peripheral surface of the cleaning roller  13  comes into contact with the charging roller  12 . The cleaning roller  13  is pressed to be in contact with the surface of the charging roller  12  by a predetermined pressing force by a pressurizing spring  34  illustrated in  FIGS. 3 and 4  serving as a cleaning member urging portion, and is rotationally driven in accordance with the rotation of the charging roller  12 . 
     More specific description will be given below. The rotation shaft  13   a  of the cleaning roller  13  is supported by a cleaning roller bearing  33 , and thus the cleaning roller  13  is rotatably supported. In addition, the cleaning roller bearing  33  is slidably supported with respect to the charging roller bearing  31 . Specifically, the cleaning roller bearing  33  is configured to be slidable in a direction toward the rotation axis of the charging roller  12  such that the cleaning roller  13  can move in the direction toward the rotation axis of the charging roller  12  along a plane perpendicular to the rotation axis of the charging roller  12 . To be noted, in the present exemplary embodiment, the rotation axis of the charging roller  12  coincides with a rotation axis of a separation member  200  that will be described later. 
     As a result of this, the cleaning roller  13  is provided to be movable between a roller contact position where the cleaning roller  13  is in contact with the surface of the charging roller  12  and a roller separation position where the cleaning roller  13  is separated from the surface of the charging roller  12 . The cleaning roller  13  cleans the charging roller  12  at the roller contact position. 
     Further, a pressurizing spring  34  serving as a cleaning member urging portion is provided between the charging roller bearing  31  and the cleaning roller bearing  33 . The pressurizing spring  34  urges the cleaning roller  13  in the direction toward the rotation axis of the charging roller  12  along the plane perpendicular to the rotation axis of the charging roller  12 . This direction serves as an urging direction. Therefore, the cleaning roller  13  is brought into pressure contact with the charging roller  12 . That is, the pressurizing spring  34  urges 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  to be movable along the urging force of the pressurizing spring  34 . In addition, in the present exemplary embodiment, the urging direction of the pressurizing spring  32  approximately coincides with the urging direction of the pressurizing spring  34 . 
     In addition, the cleaning roller  13  is supported by the charging roller bearing  31  via the cleaning roller bearing  33  and the pressurizing spring  34 . Therefore, as will be described next, in the case where the charging roller  12  is moved in a direction away from the photosensitive drum  11  by the separation member  200 , the cleaning roller  13  moves in the movement direction of the charging roller  12  in accordance with this. 
     In the configuration described above, when the photosensitive drum  11  rotates by receiving a driving force from a drive source such as a motor provided in the apparatus body  1   a , the charging roller  12  is rotated by a frictional force from the photosensitive drum  11 . Further, when the charging roller  12  rotates, the cleaning roller  13  is rotated by a frictional force from the charging roller  12 . In addition, the toner conveyance screw  38  rotates by receiving a rotational driving force from the gear  36 . 
     Separation Member 
     Next, the separation member  200  will be described with reference to  FIGS. 3 to 7B . To be noted, in  FIGS. 3 to 7B , a regulation portion  300  that will be described later is omitted. First, a separation holding configuration of holding the photosensitive drum  11 , the charging roller  12 , and the cleaning roller  13  in a state in which the charging roller  12  is separated from the photosensitive drum  11  and the cleaning roller  13  by using the separation member  200  will be described with reference to  FIGS. 5, 6, and 7A . 
     Separation Holding Configuration 
     The drum cartridge  100  includes the separation member  200  for separating the charging roller  12  from the photosensitive drum  11  and the cleaning roller  13  to secure a clearance between the charging roller  12  and the photosensitive drum  11  and a clearance between the charging roller  12  and the cleaning roller  13  while the drum cartridge  100  is transported for distribution. 
     The separation member  200  is swingably provided on the rotation shaft  12   a  of the charging roller  12 . In the present exemplary embodiment, the separation member  200  is provided on each end of the rotation shaft  12   a  of the charging roller  12  to be swingable with respect to the rotation shaft  12   a  as a swing shaft. In other words, the separation member  200  is supported by the charging roller  12  to be swingable about the rotation axis of the charging roller  12 . Therefore, the separation member  200  is movable in coordination with movement of the charging roller  12 . To be noted, since the configurations of the separation members  200  on both ends of the charging roller  12  are substantially the same, description will be given below with reference to drawings illustrating only one of the separation members  200 . 
     The separation member  200  includes two separation holding portions  210  and  220  and a swing supporting portion  230 . The swing supporting portion  230  is swingably fit on the rotation shaft  12   a  of the charging roller  12  as described above. As a result of this, the separation member  200  is swingably supported with respect to the rotation shaft  12   a . The separation holding portion  210  is disposed between the gear  36  provided on the photosensitive drum  11  and the rotation shaft  12   a  of the charging roller  12 , separates the photosensitive drum  11  and the charging roller  12  from each other, and secures a clearance therebetween. The separation holding portion  220  is disposed between the rotation shaft  12   a  of the charging roller  12  and the rotation shaft  13   a  of the cleaning roller  13 , separates the charging roller  12  and the cleaning roller  13  from each other, and secures a clearance therebetween. 
     In addition, the two separation holding portions  210  and  220  and the swing supporting portion  230  are integrally formed. Therefore, in a state in which the separation member  200  is positioned at a first phase in the swing direction, the photosensitive drum  11 , the charging roller  12 , and the cleaning roller  13  are held in a state in which the charging roller  12  is separated from the photosensitive drum  11  and the cleaning roller  13  respectively by the separation holding portions  210  and  220 . This state will be also referred to as a separation holding state. Meanwhile, in the case where the separation member  200  has swung to a second phase from the first phase in the swing direction, the separation holding state of the photosensitive drum  11  and the charging roller  12  and the separation holding state of the charging roller  12  and the cleaning roller  13  are simultaneously cancelled as will be described later. This state will be also referred to as a separation cancellation state. 
     The separation holding portion  210  is sandwiched between the rotation shaft  12   a  of the charging roller  12 , that is, the rotation shaft of the separation member  200 , and the gear  36  by the pressing force, that is, the urging force of the pressurizing spring  32  in the separation holding state of the photosensitive drum  11  and the charging roller  12 . In addition, the separation holding portion  220  is sandwiched between the rotation shaft  13   a  of the cleaning roller  13  and the rotation shaft  12   a  of the charging roller  12  by the pressing force, that is, the urging force of the pressurizing spring  34  in the separation holding state of the charging roller  12  and the cleaning roller  13 . 
     In addition, as illustrated in  FIG. 7A , the separation holding portion  210  of the separation member  200  includes an engagement portion  211  capable of engaging with the gear  36 . The engagement portion  211  includes gear teeth  211   a  serving as projection portions formed on a side surface of the separation holding portion  210  opposing the gear  36  in the separation holding state. In addition, engagement recess portions  36   a  serving as recess portions capable of engaging with the gear teeth  211   a  are defined on the entire outer peripheral surface of the gear  36 . That is, gaps between gear teeth of the gear  36  are regarded as the engagement recess portions  36   a . The gear teeth  211   a  are formed at the same pitch as the pitch of the engagement recess portions  36   a  of the gear  36 , that is, the pitch of the gear teeth of the gear  36 . In the separation holding state in which the photosensitive drum  11  and the charging roller  12  are separated from each other, the gear teeth  211   a  of the engagement portion  211  are engaged with the engagement recess portions  36   a  of the gear  36 . The separation member  200  holds the charging roller  12  against the urging force of the pressurizing spring  32  at the separation position where the charging roller  12  is separated from the photosensitive drum  11  in a state in which the engagement portion  211  is engaged with the gear  36  serving as a rotary member. 
     In addition, the separation holding portion  220  of the separation member  200  includes an engagement portion  221  serving as a cleaning member engagement portion capable of engaging with the rotation shaft  13   a  of the cleaning roller  13  serving as a part of a cleaning member. The engagement portion  221  is a recess portion provided on a side surface of the separation holding portion  220  that opposes the rotation shaft  13   a  in the separation holding state and having a curvature radius approximately equal to the outer diameter of the outer peripheral surface of the rotation shaft  13   a  having a cylindrical shape. In addition, the engagement portion  221  is engaged with the rotation shaft  13   a  in the separation holding state in which the charging roller  12  and the cleaning roller  13  are separated from each other. In other words, at this time, the separation member  200  holds the cleaning roller  13  at the separation position where the charging roller  12  and the cleaning roller  13  are separated from each other against the urging force of the pressurizing spring  34  in a state in which the engagement portion  221  is engaged with the rotation shaft  13   a  serving as a part of a cleaning member. 
     The engagement portion  221  of the separation holding portion  220  is formed to be engaged with the rotation shaft  13   a  of the cleaning roller  13  in a state in which the engagement portion  211  of the separation holding portion  210  is engaged with the gear  36 . Therefore, in the state in which the separation member  200  is positioned at the first phase in the swing direction, the engagement portion  211  is engaged with the gear  36  and the engagement portion  221  is engaged with the rotation shaft  13   a . Thus, the charging roller  12  and the cleaning roller  13  are held in a state of being separated from each other. As a result of this, the elastic layer  12   b  of the charging roller  12  is separated from the photosensitive drum  11 , the charging roller  12  is separated from the cleaning roller  13 , and a clearance therebetween is secured, for example, when transporting the drum cartridge  100 . 
     Configuration of Separation Cancellation 
     Next, a configuration of separation cancellation in which the separation holding state of the photosensitive drum  11  and the charging roller  12  and the separation holding state of the charging roller  12  and the cleaning roller  13  are cancelled by the separation member  200  will be described with reference to  FIGS. 3, 4, and 7B . When a brand-new drum cartridge  100  is attached to the apparatus body  1   a  illustrated in  FIG. 1  and the image forming apparatus  1  illustrated in  FIG. 1  is booted up, a rotational driving force is input to the photosensitive drum  11  from a motor provided in the apparatus body  1   a  in a starting operation performed by the image forming apparatus  1 . 
     When the drum cartridge  100  is attached to the apparatus body  1   a , the drum cartridge  100  is in the separation holding state in which the charging roller  12  is separated from the photosensitive drum  11  and the cleaning roller  13  as illustrated in  FIG. 7A . When the rotation of the photosensitive drum  11  is started in this separation holding state, the gear  36  rotates together with the rotation of the photosensitive drum  11  as illustrated in  FIG. 7B . Then, the engagement portion  211  engaged with the gear  36  receives the rotational force of the gear  36 , and the separation member  200  swings in a predetermined direction α indicated by an arrow in  FIG. 7B . 
     As a result of the separation member  200  swinging in this manner, the engagement between the engagement portion  211  and the gear  36  is released, and the separation holding portion  210  is released from a state of being sandwiched between the rotation shaft  12   a  of the charging roller  12 , that is, the swing shaft of the separation member  200 , and the gear  36 . As a result of this, the state in which the charging roller  12  is held at the separation position is automatically cancelled. 
     In addition, as a result of the separation member  200  swinging, the engagement between the engagement portion  221  and the rotation shaft  13   a  of the cleaning roller  13  is released, and the separation holding portion  220  is released from the state of being sandwiched between the rotation shaft  12   a  of the charging roller  12  and the rotation shaft  13   a  of the cleaning roller  13 . As a result of this, the state in which the cleaning roller  13  is held at the roller separation position is automatically cancelled. That is, in the present exemplary embodiment, when the gear  36  rotates in the starting operation of the image forming apparatus  1  after the drum cartridge  100  is attached to the apparatus body  1   a , the separation member  200  swings and the separation holding states of the charging roller  12  and the cleaning roller  13  are automatically cancelled at the same time. 
     Regulation of Movement of Separation Member 
     Next, a configuration capable of suppressing unintentional release of the engagement between the engagement portion  211  of the separation member  200  and the gear  36  even in the case where a strong vibration is applied to the drum cartridge  100  while, for example, the drum cartridge  100  is being transported will be described with reference to  FIGS. 8 to 11B . In the present exemplary embodiment, unintentional release of the engagement between the engagement portion  211  of the separation member  200  and the gear  36  is suppressed by a regulation portion  300 . That is, the regulation portion  300  regulates movement of the separation member  200  in a direction to increase the distance between the swing center of the separation member  200  and the rotation center of the gear  36  in the state in which the engagement portion  211  and the gear  36  are engaged with each other, such that the engagement between the engagement portion  211  and the gear  36  is not released. 
     In the present exemplary embodiment, the regulation portion  300  includes an abutting portion  302  provided on the separation member  200  and an abutted portion  301  provided in the drum container  30  as illustrated in  FIG. 8 . As illustrated in  FIG. 9A , the abutting portion  302  is provided to project in the rotation axis direction of the photosensitive drum  11  from an end surface of the separation holding portion  210 . Therefore, the abutting portion  302  is provided further on the outside than the photosensitive drum  11  in the rotation axis direction. 
     As illustrated in  FIG. 9B , the abutted portion  301  is provided on a side wall  30   a  of the drum container  30  opposing an end portion of the photosensitive drum  11  in the rotation axis direction. Specifically, the abutted portion  301  is formed by causing, in a side surface of the side wall  30   a , a portion further on the charging roller  12  side than a portion opposing the end portion of the photosensitive drum  11  in the rotation axis direction to project to the inside in the rotation axis direction, that is, toward the charging roller  12  side. The abutted portion  301  having such a structure is formed such that the abutting portion  302  abuts the abutted portion  301  in the case where the separation member  200  moves in the direction to increase the distance between the swing center of the separation member  200  and the rotation center of the gear  36  in the state in which the engagement portion  211  is engaged with the gear  36 . 
     That is, the abutted portion  301  includes an abutted surface  301   a  that the abutting portion  302  abuts. The abutted surface  301   a  is formed on the side toward which the separation member  200  moves to increase the distance between the swing center of the separation member  200  and the rotation center of the gear  36  with respect to the abutting portion  302  in the state in which the separation member  200  is in the separation holding state. Here, the separation member  200  is provided to be swingable with respect to the rotation shaft  12   a  of the charging roller  12 , and the swing center of the separation member  200  approximately coincides with the rotation center of the charging roller  12 . In addition, the charging roller  12  is urged toward the photosensitive drum  11  by the pressurizing spring  32 , and the separation holding portion  210  of the separation member  200  is nipped between the rotation shaft  12   a  of the charging roller  12  and the gear  36  by the urging force of the pressurizing spring  32 . 
     Therefore, in the present exemplary embodiment, the direction in which the separation member  200  moves to increase the distance between the swing center of the separation member  200 , that is, the rotation center of the charging roller  12 , and the rotation center of the gear  36 , that is, the rotation center of the photosensitive drum  11 , is opposite to the urging direction of the pressurizing spring  32 . Therefore, the abutted surface  301   a  is positioned in a direction opposite to the urging direction of the pressurizing spring  32  with respect to the abutting portion  302  when the separation member  200  is in the separation holding state. Therefore, as a result of the abutting portion  302  abutting the abutted surface  301   a , the movement of the separation member  200  in a direction away from the gear  36  against the urging force of the pressurizing spring  32  is regulated. 
     Here, as illustrated in  FIGS. 10A and 10B , the distance between the abutting portion  302  and the abutted portion  301  in a state in which the separation holding state is taken and the separation member  200  has not moved in the direction to increase the distance between the swing center of the separation member  200  and the rotation center of the gear  36  is denoted by A. The distance A is preferably larger than 0. That is, a gap is preferably present between the abutting portion  302  and the abutted portion  301  in this state. To be noted, the separation holding state is a state in which the separation member  200  is holding the charging roller  12  at the separation position. In addition, the state in which the separation member  200  has not moved in the direction to increase the distance between the swing center of the separation member  200  and the rotation center of the gear  36  is a state in which the separation holding portion  210  of the separation member  200  is pressed against the gear  36  and is not separated from the gear  36 . In this state, the distance A is smaller than a length of overlap between a gear tooth  211   a  and an engagement recess portion  36   a  in a projecting direction of the gear tooth  211   a  as viewed in the rotation direction of the gear  36 , that is, smaller than the amount of engagement between the gear tooth  211   a  and the engagement recess portion  36   a . The length of overlap will be also referred to as an engagement amount B. 
     That is, as illustrated in  FIGS. 10A and 10B , in the relationship between the distance A between the abutting portion  302  and the abutted surface  301   a  and the engagement amount B between the gear  36  and the engagement portion  211  in the separation holding state, the distance A is smaller than the engagement amount B in the sliding direction of the charging roller bearing  31 . That is, A&lt;B holds. This configuration regulates the movement of the separation member  200  in the direction to increase the distance between the swing center of the separation member  200  and the rotation center of the gear  36  in the state in which the engagement portion  211  is engaged with the gear  36 , such that the engagement between the engagement portion  211  and the gear  36  is not released. 
     For example, there is a risk that the charging roller  12  moves in a direction away from the photosensitive drum  11  against the urging force of the pressurizing spring  32  by being vibrated or dropped while the drum cartridge  100  is transported. In this case, the separation member  200  supported on the rotation shaft of the charging roller  12  also moves in the direction away from the photosensitive drum  11 . However, since the distance A is smaller than the engagement amount B as described above, the abutting portion  302  abuts the abutted portion  301  before the engagement between the engagement portion  211  and the gear  36  is released, thus the movement of the separation member  200  is regulated, and the cancellation of the separation holding state is suppressed. 
     To be noted, when the separation holding state is cancelled, the gear  36  rotates together with the photosensitive drum  11  and the separation member  200  swings, and the engagement between the engagement portion  211  and the gear  36  is released. At this time, the separation member  200  is urged toward the photosensitive drum  11  together with the charging roller  12  by the pressurizing spring  32 , and therefore moves toward the photosensitive drum  11  in accordance with the release of engagement between the engagement portion  211  and the gear  36 . In other words, the abutting portion  302  provided on the separation member  200  moves in a direction away from the abutted portion  301  while the separation member  200  is swinging. Therefore, the separation member  200  swings to cancel the separation holding state without interference between the abutting portion  302  and the abutted portion  301 . 
     In addition, in the present exemplary embodiment, rotation of the separation member  200  from the position at which the separation member  200  is in the separation holding state in a direction opposite to such a rotation direction that the separation holding state is automatically cancelled, that is, in a direction opposite to the predetermined direction α is regulated in the state in which the abutting portion  302  is abutting the abutted portion  301 . Therefore, as illustrated in  FIG. 11A , the abutted portion  301  is formed such that a reaction force P in the normal direction applied to the abutting portion  302  when the abutting portion  302  abuts the abutted portion  301  acts in a direction to swing the separation member  200  in the direction opposite to the predetermined direction α. 
     In the present exemplary embodiment, as illustrated in  FIG. 11B , the abutted surface  301   a  of the abutted portion  301  is inclined in the direction opposite to the predetermined direction α with respect to a direction perpendicular to an urging direction S of the pressurizing spring  32  illustrated in  FIG. 9A  and so forth. In other words, the abutted surface  301   a  is made up of a surface inclined with respect to the sliding direction of the charging roller bearing  31 , which is the same direction as the urging direction S. 
     Specific description will be given below. The abutted surface  301   a  is formed as such an inclined surface that the reaction force P in the normal direction applied to the abutting portion  302  when the abutting portion  302  abuts the abutted surface  301   a  includes a force component that rotates the separation member  200  in the direction opposite to the direction in which the separation member  200  rotates at the time of automatic cancellation, that is, in the direction opposite to the predetermined direction α. In other words, as illustrated in  FIG. 11A , the reaction force P in the normal direction generates a torque T that rotates the separation member  200  in the direction opposite to the predetermined direction α. 
     In the present exemplary embodiment, as illustrated in  FIG. 11B , the normal direction N of the abutted surface  301   a  is more toward the cleaning blade  15   a  side than a direction toward the rotation axis of the photosensitive drum  11 , that is, than the urging direction S, in the sliding direction of the charging roller bearing  31 . As illustrated in  FIG. 2 , the cleaning blade  15   a  abuts the photosensitive drum  11  in a counter direction with respect to the rotation direction of the photosensitive drum  11 . In addition, the cleaning blade  15   a  is provided upstream of the charging roller  12  in the rotation direction of the photosensitive drum  11  to clean the surface of the photosensitive drum  11  before charging the photosensitive drum  11 . The separation member  200  swings in the predetermined direction α as a result of the photosensitive drum  11  rotating in the rotation direction β. Therefore, the cleaning blade  15   a  is positioned in a direction opposite to the predetermined direction α from the separation member  200 . Therefore, in the present exemplary embodiment, the normal direction N of the abutted surface  301   a  is more toward the cleaning blade  15   a  side than the urging direction S. 
     In the case where a big impact is applied to the drum cartridge  100  while the drum cartridge  100  is transported or the like, the following problem may arise. That is, there is a possibility that the relationship between the distance A between the abutting portion  302  and the abutted surface  301   a  and the engagement amount B between the gear  36  and the engagement portion  211  in the separation holding state is reversed from the state described above as a result of deformation of the drum container  30  or the like. That is, there is a possibility that the relationship changes to A&gt;B. 
     However, by forming the abutted surface  301   a  in an inclined shape as described above, unintended cancellation of the separation holding state can be suppressed even in the case where, for example, the relationship changes to A&gt;B and the gear  36  and the engagement portion  211  are temporarily separated from each other. That is, when the separation member  200  is moved by the impact and the abutting portion  302  abuts the abutted surface  301   a , the reaction force P in the normal direction that rotates the separation member  200  in the direction opposite to the direction in which the separation member  200  rotates at the time of automatic cancellation, that is, in the direction opposite to the predetermined direction α, is generated in the abutting portion  302 . Therefore, rotation of the separation member  200  in the predetermined direction α is suppressed, and cancellation of the separation holding state can be suppressed even when A&gt;B holds. 
     As described above, even in the case where a vibration or an impact is applied to the drum cartridge  100  and the separation member  200  has moved in the direction away from the gear  36 , the movement of the separation member  200  is regulated, and release of engagement between the engagement portion  211  and the gear  36  can be suppressed. As a result of this, occurrence of unintended cancellation of the separation holding state of the photosensitive drum  11  and the charging roller  12  and further occurrence of unintended cancellation of the separation holding state of the charging roller  12  and the cleaning roller  13  can be reduced. 
     Second Exemplary Embodiment 
     A second exemplary embodiment will be described with reference to  FIGS. 12 to 16B . Whereas the first exemplary embodiment described above is a configuration including the cleaning roller  13 , the present exemplary embodiment is a configuration not including the cleaning roller  13 . In addition, in the present exemplary embodiment, the position of a regulation portion  300 A that regulates the movement of a separation member  200 A is different from that of the first exemplary embodiment. The other elements and effects are the same as in the first exemplary embodiment described above, and therefore the same elements are denoted by the same reference signs and description thereof will be omitted or simplified. Elements different from the first exemplary embodiment will be mainly described below. 
     As illustrated in  FIG. 12 , the rotation shaft  12   a  of the charging roller  12  is held by a charging roller bearing  31 A serving as a roller holding portion, and thus the charging roller  12  is rotatably supported. In addition, the charging roller bearing  31 A is slidably supported with respect to the drum container  30  similarly to the first exemplary embodiment. Specifically, the charging roller bearing  31 A is configured to be guided to be slidable in a direction toward the rotation axis of the photosensitive drum  11  by the slide guiding portion  30   c  provided in the drum container  30 . In the illustrated example, a groove  31 Aa is defined in the charging roller bearing  31 A along the sliding direction thereof, and the slide guiding portion  30   c  engages with the groove  31 Aa to guide the charging roller bearing  31 A in the direction toward the rotation axis of the photosensitive drum  11 . 
     In addition, similarly to the first exemplary embodiment, the pressurizing spring  32  serving as an urging portion is provided between the drum container  30  and the charging roller bearing  31 A. The pressurizing spring  32  urges the charging roller  12  in the direction toward the rotation axis of the photosensitive drum  11  along the plane perpendicular to the rotation axis of the photosensitive drum  11 . This direction serves as an urging direction. 
     To be noted, since the cleaning roller  13  is not provided in the present exemplary embodiment unlike the first exemplary embodiment, the configuration of the charging roller bearing  31 A is different from the configuration of the charging roller bearing  31  of the first exemplary embodiment in this point. 
     In the configuration described above, when the photosensitive drum  11  rotates by receiving a driving force from a drive source such as a motor provided in the apparatus body  1   a  illustrated in  FIG. 1 , the charging roller  12  is rotated by a frictional force from the photosensitive drum  11 . In addition, the toner conveyance screw  38  rotates by receiving a rotational driving force from the gear  36 . 
     Separation Member 
     Next, the separation member  200 A of the present exemplary embodiment will be described. In the present exemplary embodiment, the cleaning roller  13  is not provided unlike the first exemplary embodiment. Therefore, the separation member  200 A does not include the separation holding portion  220  unlike the first exemplary embodiment, and includes the one separation holding portion  210  and the swing supporting portion  230 . The swing supporting portion  230  is swingably fit on the rotation shaft  12   a  of the charging roller  12 . The separation holding portion  210  is disposed between the gear  36  provided on the photosensitive drum  11  and the rotation shaft  12   a  of the charging roller  12 , separates the photosensitive drum  11  and the charging roller  12  from each other, and secures a clearance therebetween. The configurations and effects of the swing supporting portion  230  and the separation holding portion  210  are the same as in the first exemplary embodiment. 
     Therefore, as illustrated in  FIG. 14B , the separation holding portion  210  includes the engagement portion  211  capable of engaging with the gear  36 . When a rotational driving force is input to the photosensitive drum  11  from a motor provided in the apparatus body  1   a , the engagement portion  211  engaged with the gear  36  receives the rotational force of the gear  36 , and thus the separation member  200 A swings in the predetermined direction α, which is indicated by an arrow in  FIGS. 16A and 16B . As a result of the separation member  200 A swinging in this manner, the engagement between the engagement portion  211  and the gear  36  is released, and the separation holding portion  210  is released from a state of being sandwiched between the rotation shaft  12   a  of the charging roller  12 , that is, the swing shaft of the separation member  200 A, and the gear  36 . As a result of this, the state in which the charging roller  12  is held at the separation position is automatically cancelled. 
     Regulation of Movement of Separation Member 
     Next, a configuration capable of suppressing unintentional release of the engagement between the engagement portion  211  of the separation member  200 A and the gear  36  will be described. Also, in the present exemplary embodiment, unintentional release of the engagement between the engagement portion  211  of the separation member  200 A and the gear  36  is suppressed by a regulation portion  300 A. That is, the regulation portion  300 A regulates movement of the separation member  200 A in a direction to increase the distance between the swing center of the separation member  200 A and the rotation center of the gear  36  in the state in which the engagement portion  211  and the gear  36  are engaged with each other, such that the engagement between the engagement portion  211  and the gear  36  is not released. 
     In the present exemplary embodiment, the regulation portion  300 A includes an abutting portion  302 A provided on the separation member  200 A and an abutted portion  301 A provided in the drum container  30  as illustrated in  FIG. 12 . As illustrated in  FIG. 13A , the abutting portion  302 A is provided to project in a direction opposite to the photosensitive drum  11  from an outer peripheral surface of the swing supporting portion  230 . Therefore, the abutting portion  302 A is provided further on the inside than the charging roller bearing  31 A in the rotation axis direction of the charging roller  12 . 
     As illustrated in  FIG. 13B , the abutted portion  301 A is provided on the connecting portion  30   b  interconnecting side walls  30   a  at both end portions of the drum container  30  in the rotation axis direction of the photosensitive drum  11 . Specifically, the abutted portion  301 A is formed by causing a part of the connecting portion  30   b  to project toward the charging roller  12  side. The abutted portion  301 A having such a structure is formed such that the abutting portion  302 A abuts the abutted portion  301 A in the case where the separation member  200 A moves in the direction to increase the distance between the swing center of the separation member  200 A and the rotation center of the gear  36  in the state in which the engagement portion  211  is engaged with the gear  36 . 
     That is, the abutted portion  301 A includes an abutted surface  301 Aa that the abutting portion  302 A abuts. The abutted surface  301 Aa is formed on the side toward which the separation member  200 A moves to increase the distance between the swing center of the separation member  200 A and the rotation center of the gear  36  with respect to the abutting portion  302 A in the state in which the separation member  200 A is in the separation holding state. To be noted, also in the present exemplary embodiment, the direction in which the separation member  200 A moves to increase the distance between the swing center of the separation member  200 A, that is, the rotation center of the charging roller  12 , and the rotation center of the gear  36 , that is, the rotation center of the photosensitive drum  11 , is opposite to the urging direction of the pressurizing spring  32 . 
     Therefore, the abutted surface  301 Aa is positioned in a direction opposite to the urging direction of the pressurizing spring  32  with respect to the abutting portion  302 A when the separation member  200 A is in the separation holding state. Therefore, as a result of the abutting portion  302 A abutting the abutted surface  301 Aa, the movement of the separation member  200 A in a direction away from the gear  36  against the urging force of the pressurizing spring  32  is regulated. 
     Here, as illustrated in  FIGS. 15A and 15B , the distance between the abutting portion  302 A and the abutted portion  301 A in a state in which the separation holding state is taken and the separation member  200 A has not moved in the direction to increase the distance between the swing center of the separation member  200 A and the rotation center of the gear  36  is denoted by A. The distance A is preferably larger than 0. That is, a gap is preferably present between the abutting portion  302 A and the abutted portion  301 A in this state. To be noted, the separation holding state is a state in which the separation member  200 A is holding the charging roller  12  at the separation position. In addition, the state in which the separation member  200 A has not moved in the direction to increase the distance between the swing center of the separation member  200 A and the rotation center of the gear  36  is a state in which the separation member  200 A is pressed against the gear  36  and is not separated from the gear  36 . In this state, the distance A is smaller than a length of overlap between a gear tooth  211   a  and an engagement recess portion  36   a  in a projecting direction of the gear tooth  211 A as viewed in the rotation direction of the gear  36 , that is, smaller than the amount of engagement between the gear tooth  211   a  and the engagement recess portion  36   a . The length of overlap will be also referred to as an engagement amount B as illustrated in  FIGS. 14A and 14B . 
     That is, as illustrated in  FIGS. 14A to 15B , in the relationship between the distance A between the abutting portion  302 A and the abutted surface  301 Aa and the engagement amount B between the gear  36  and the engagement portion  211  in the separation holding state, the distance A is smaller than the engagement amount B in the sliding direction of the charging roller bearing  31 A. That is, A&lt;B holds. This configuration regulates the movement of the separation member  200 A in the direction to increase the distance between the swing center of the separation member  200 A and the rotation center of the gear  36  in the state in which the engagement portion  211  is engaged with the gear  36 , such that the engagement between the engagement portion  211  and the gear  36  is not released. 
     According to this configuration, similarly to the first exemplary embodiment, the engagement between the engagement portion  211  and the gear  36  is less likely to be released even in the case where the charging roller  12  moves in a direction away from the photosensitive drum  11  against the urging force of the pressurizing spring  32  by being vibrated or dropped while the drum cartridge  100  is transported. That is, since the distance A is smaller than the engagement amount B, the abutting portion  302 A abuts the abutted portion  301 A before the engagement between the engagement portion  211  and the gear  36  is released, thus the movement of the separation member  200 A is regulated, and the cancellation of the separation holding state is suppressed. 
     To be noted, also in the present exemplary embodiment, when the separation holding state is cancelled, since the separation member  200 A is urged toward the photosensitive drum  11  together with the charging roller  12  by the pressurizing spring  32 , the separation member  200 A moves toward the photosensitive drum  11  in accordance with the release of engagement between the engagement portion  211  and the gear  36 . In other words, the abutting portion  302 A provided on the separation member  200 A moves in a direction away from the abutted portion  301 A while the separation member  200 A is swinging. Therefore, the separation member  200 A swings to cancel the separation holding state without interference between the abutting portion  302 A and the abutted portion  301 A. 
     In addition, also in the present exemplary embodiment, rotation of the separation member  200 A from the position at which the separation member  200 A is in the separation holding state in a direction opposite to such a rotation direction that the separation holding state is automatically cancelled, that is, in a direction opposite to the predetermined direction α is regulated in the state in which the abutting portion  302 A is abutting the abutted portion  301 A. Therefore, as illustrated in  FIG. 16A , the abutted portion  301 A is formed such that a reaction force P in the normal direction applied to the abutting portion  302 A when the abutting portion  302 A abuts the abutted portion  301 A acts in a direction to swing the separation member  200 A in the direction opposite to the predetermined direction α. 
     In the present exemplary embodiment, as illustrated in  FIG. 16B , the abutted surface  301 Aa of the abutted portion  301 A is inclined in the direction opposite to the predetermined direction α with respect to a direction perpendicular to the urging direction S of the pressurizing spring  32  illustrated in  FIG. 13A  and so forth. In other words, the abutted surface  301 Aa is made up of a surface inclined with respect to the sliding direction of the charging roller bearing  31 A, which is the same direction as the urging direction S. 
     Specific description will be given below. The abutted surface  301 Aa is formed as such an inclined surface that the reaction force P in the normal direction applied to the abutting portion  302 A when the abutting portion  302 A abuts the abutted surface  301 Aa includes a force component that rotates the separation member  200 A in the direction opposite to the predetermined direction α in which the separation member  200 A rotates at the time of automatic cancellation. In other words, as illustrated in  FIG. 16A , the reaction force P in the normal direction generates the torque T that rotates the separation member  200 A in the direction opposite to the predetermined direction α. 
     Also in the present exemplary embodiment, as illustrated in  FIG. 16B , the normal direction N of the abutted surface  301 Aa is more toward the cleaning blade  15   a  side than a direction toward the rotation axis of the photosensitive drum  11 , that is, than the urging direction S, in the sliding direction of the charging roller bearing  31 A. 
     By forming the abutted surface  301 Aa in an inclined shape in this manner, unintended cancellation of the separation holding state can be suppressed even in the case where, for example, A&gt;B holds and the gear  36  and the engagement portion  211  are temporarily separated from each other. That is, when the separation member  200 A is moved by the impact and the abutting portion  302 A abuts the abutted surface  301 Aa, the reaction force P in the normal direction that rotates the separation member  200 A in the direction opposite to the direction in which the separation member  200 A rotates at the time of automatic cancellation, that is, in the direction opposite to the predetermined direction α, is generated in the abutting portion  302 A. Therefore, rotation of the separation member  200 A in the predetermined direction α is suppressed, and cancellation of the separation holding state can be suppressed even when A&gt;B holds. 
     Also in the present exemplary embodiment, even in the case where a vibration or an impact is applied to the drum cartridge and the separation member  200 A has moved in the direction away from the gear  36 , the movement of the separation member  200 A is regulated, and release of engagement between the engagement portion  211  and the gear  36  can be suppressed. As a result of this, occurrence of unintended cancellation of the separation holding state of the photosensitive drum  11  and the charging roller  12  can be reduced. 
     Other Embodiments 
     Although a gear serving as a rotary member is provided on a rotation shaft of a photosensitive drum in the exemplary embodiments described above, the rotary member may be provided at a position deviated from the rotation shaft of the photosensitive drum. For example, the rotary member may be a gear that transmits rotation from a motor to the photosensitive drum. In addition, the rotary member may be driven separately from the photosensitive drum. Further, although a configuration in which the rotary member is a gear and an engagement portion includes a projection portion that engages with the gear has been described in the exemplary embodiments described above, a configuration in which the rotary member includes a projection portion and the engagement portion includes a recess portion that engages with the projection portion may be employed. 
     In addition, although a separation member is swingably provided on a rotation shaft of a charging roller in the exemplary embodiments described above, the separation member may be provided at a position deviated from the rotation shaft of the charging roller. Further, although a configuration in which the separation member swings in accordance with the rotation of the rotary member has been described in the exemplary embodiments described above, the engagement between the engagement portion and the rotary member may be released by, for example, sliding movement of the separation member caused by the rotation of the rotary member. 
     In addition, the photosensitive member may be a photosensitive belt or the like instead of the photosensitive drum. Examples of the photosensitive unit include, in addition to the drum cartridge described above, a process cartridge in which the drum cartridge and a developing unit are combined. Further, any image forming apparatus may be used as long as the image forming apparatus performs image formation by using a photosensitive member. For example, the image forming apparatus may be a copier, a printer, a facsimile machine, or a multifunctional apparatus having a plurality of functions of these. 
     Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2018-179899, filed Sep. 26, 2018, which is hereby incorporated by reference herein in its entirety.