JP6287336B2 - Process cartridge and photoreceptor unit - Google Patents

Description

The present invention relates to a process cartridge and a photosensitive unit including a developing roller and a photosensitive drum.

  As a process cartridge used in an image forming apparatus such as a laser printer, a housing that accommodates the developer, a developing roller that carries the developer on the outer peripheral surface, a gap between both ends of the outer peripheral surface of the developing roller and the housing There is known one provided with a photoconductive drum on which a developer image is formed by supplying a developer from an arranged seal member and a developing roller (see, for example, Patent Document 1).

JP 2012-159828 A

  By the way, after the developer image is transferred to a sheet or the like, the developer remaining on the photosensitive drum may move from the photosensitive drum to the developing roller. At this time, if the developer adheres to the end portion of the outer peripheral surface of the developing roller, the developer may enter between the developing roller and the seal member due to the rotation of the developing roller, which may reduce the sealing performance.

The present invention has been made in view of the above background, and suppresses the developer from entering between the developing roller and the seal member when the developer moves from the photosensitive drum onto the developing roller. An object of the present invention is to provide a process cartridge and a photoconductor unit that can perform the above process.

In order to achieve the above-described object, a process cartridge according to the present invention is configured to have a housing configured to contain a developer, and to be rotatably provided on the housing, and to carry the developer on an outer peripheral surface. The developing roller, a seal member disposed between both ends of the outer peripheral surface of the developing roller in the rotation axis direction of the developing roller and the housing, and a rotation member provided rotatably at a position facing the developing roller. A photosensitive drum configured to form a developer image when the developer is supplied; and a developer return member.
The developer returning member is disposed at a position where at least a part of the developer returning member overlaps with the seal member when viewed from the direction orthogonal to the rotation axis of the photosensitive drum, and is in contact with the outer peripheral surface of the photosensitive drum. The developer adhering to is moved inward in the rotational axis direction of the photosensitive drum.

  According to such a configuration, the developer is moved from the photosensitive drum to the developing roller by moving the developer attached to the outer peripheral surface of the photosensitive drum by the developer returning member toward the inner side in the rotation axis direction of the photosensitive drum. It is possible to suppress the developer from adhering to the end portion of the outer peripheral surface of the developing roller when moved to. As a result, the developer can be prevented from entering between the developing roller and the seal member.

  In the above-described process cartridge, the developer return member is a groove that extends toward the inner side in the rotational axis direction of the photosensitive drum from the upstream side to the downstream side in the rotational direction of the photosensitive drum at a portion that contacts the outer peripheral surface of the photosensitive drum. It can be set as the structure which has these.

  According to this, since the developer can be moved along the groove, the developer can be moved efficiently.

  In the process cartridge described above, the developer return member may be arranged at both ends of the outer peripheral surface of the photosensitive drum in the rotation axis direction of the photosensitive drum.

  According to this, since the developer returning member can be reduced in size compared to the case where the developer returning member is provided longer in the rotation axis direction of the photosensitive drum, the process cartridge can be reduced in size. In other words, the developer return member can be arranged in a narrow space, compared to the case where the developer return member is provided longer in the rotation axis direction, so that the process cartridge can be enlarged due to the provision of the developer return member. Can be suppressed.

  In the process cartridge described above, the outer peripheral surface of the developing roller has a contact region that contacts the seal member, and a non-contact region that is inside the contact region in the rotation axis direction of the developing roller and does not contact the seal member. The developer returning member can be configured to be disposed at a position overlapping both the contact area and the non-contact area when viewed from the direction orthogonal to the rotation axis of the photosensitive drum.

  According to this, the developer attached to the outer peripheral surface of the photosensitive drum by the developer return member can be moved to a position corresponding to the non-contact area, so that when the developer moves to the developing roller, It is possible to suppress the developer from adhering to the contact area of the developing roller. Accordingly, it is possible to further suppress the developer from entering between the developing roller and the seal member.

  In the process cartridge described above, the developer return member can be made of a fiber.

  The process cartridge described above includes an adhering matter removing member configured to remove the adhering matter adhering to the outer peripheral surface of the photosensitive drum after the developer image is transferred by contacting the outer peripheral surface of the photosensitive drum. The developer returning member may be arranged downstream of the deposit removing member and upstream of the developing roller in the rotation direction of the photosensitive drum.

  According to this, even if the developer moves to a position corresponding to the end portion of the outer peripheral surface of the developing roller by receiving a force between the photosensitive drum and the deposit removing member, it is arranged on the downstream side in the rotation direction. By the developer returning member thus formed, the developer can be returned to the inside in the rotation axis direction. Thereby, even in the configuration in which the deposit removing member that contacts the outer peripheral surface of the photosensitive drum is provided, the developer can be prevented from entering between the developing roller and the seal member.

  Further, the process cartridge described above is in contact with the outer peripheral surface of the photosensitive drum, and a developer removing member configured to remove the developer remaining on the outer peripheral surface of the photosensitive drum after transferring the developer image. The developer return member may be arranged downstream of the position where the developer image is transferred and upstream of the developer removal member in the rotational direction of the photosensitive drum. it can.

  According to this, the developer attached to the outer peripheral surface of the photosensitive drum can be removed by the developer removing member after the developer is moved by the developer returning member to the inner side in the rotation axis direction. The movement of the developer itself can be suppressed. Accordingly, it is possible to further suppress the developer from entering between the developing roller and the seal member.

  In the process cartridge described above, the groove of the developer return member may be configured to extend at an angle of 45 ° or less with respect to the rotation axis of the photosensitive drum.

  According to the present invention, when the developer moves from the photosensitive drum onto the developing roller, the developer can be prevented from entering between the developing roller and the seal member.

1 is a diagram illustrating a schematic configuration of an image forming apparatus in which a process cartridge is used. It is sectional drawing of a process cartridge. FIG. 4 is a perspective view showing a structure of a rear portion of a developing unit that constitutes a process cartridge. FIG. 4 is a diagram illustrating a developing unit, a photosensitive drum, a toner returning member and a cleaning roller as an example of a developer returning member. It is an expanded sectional view of a process cartridge. FIG. 4A is a diagram showing a developing roller, a photosensitive drum, a cleaning unit, and a toner return member, and FIG. 4B is a diagram for explaining a method for attaching the toner return member. FIG. 6 is an enlarged view of a contact portion of a toner return member. FIGS. 5A and 5B are views for explaining the operation of the process cartridge according to the embodiment, and FIGS. It is an expanded sectional view of a process cartridge concerning a 2nd embodiment. FIG. 10 is a diagram (a) and (b) showing a toner return member according to a modification.

[First Embodiment]
Next, the first embodiment will be described in detail with reference to the drawings as appropriate. In the following, first, a schematic configuration of the image forming apparatus in which the process cartridge according to the embodiment is used will be described, and then a detailed configuration of the process cartridge will be described. In the following description, the direction will be described with reference to the user who uses the image forming apparatus. Specifically, the right side of FIG. 1 that is the front side when viewed from the user is “front”, the left side of FIG. 1 that is the back side when viewed from the user is “rear”, and the front side of FIG. "The back side of the paper is" right ". Further, the vertical direction in FIG.

<Schematic configuration of laser printer>
As shown in FIG. 1, a laser printer 1 as an example of an image forming apparatus mainly includes a paper feed unit 3, an exposure device 4, a process cartridge 5, and a fixing device 8 in a main body housing 2. ing.

  The paper feed unit 3 is provided at a lower portion in the main body housing 2 and mainly includes a paper feed tray 31 that accommodates the paper S, a paper pressing plate 32, a paper feed mechanism 33, and a registration roller 34. . The paper feeding unit 3 brings the paper S in the paper feeding tray 31 upward by the paper pressing plate 32, feeds the paper S one by one by the paper feeding mechanism 33, and supplies it between the photosensitive drum 61 and the transfer roller 63.

  The exposure apparatus 4 is disposed in the upper part of the main body housing 2 and includes a laser light emitting unit (not shown), a polygon mirror, a lens, a reflecting mirror, and the like that are not shown. The exposure device 4 exposes the surface of the photoconductive drum 61 by scanning the surface of the photoconductive drum 61 with laser light (refer to the chain line) based on the image data emitted from the laser light emitting unit at high speed.

  The process cartridge 5 is disposed below the exposure apparatus 4 and is detachably mounted on the main body housing 2 through an opening formed when the front cover 21 provided on the main body housing 2 is opened. Yes. The process cartridge 5 includes a photoconductor unit 6 and a developing unit 7. The photosensitive unit 6 mainly includes a photosensitive drum 61, a charger 62, and a transfer roller 63. The developing unit 7 includes a developing roller 71, a supply roller 72, a layer thickness regulating blade 73, and a developer. As an example, a storage unit 74 that stores positively chargeable toner and an agitator 75 are mainly provided.

  In the process cartridge 5, the surface of the rotating photosensitive drum 61 is uniformly positively charged by the charger 62 and exposed by the laser beam from the exposure device 4, so that the static charge based on the image data is formed on the photosensitive drum 61. An electrostatic latent image is formed. Further, the toner in the container 74 is supplied to the supply roller 72 while being stirred by the agitator 75, and is supplied from the supply roller 72 to the developing roller 71. Then, the toner is carried on the developing roller 71 after the developing roller 71 is regulated to a constant thickness between the developing roller 71 and the layer thickness regulating blade 73 by the rotation of the developing roller 71.

  Thereafter, the toner carried on the developing roller 71 is supplied to the photosensitive drum 61 to visualize the electrostatic latent image, and a toner image as an example of a developer image is formed on the photosensitive drum 61. . Then, the paper S supplied from the paper supply unit 3 is conveyed between the photosensitive drum 61 and the transfer roller 63, whereby the toner image on the photosensitive drum 61 is transferred to the paper S.

  The fixing device 8 is disposed behind the process cartridge 5 and sandwiches the fixing belt between a heating unit 81 having a halogen heater, a fixing belt, a nip plate, and the like, which are not shown, and a nip plate of the heating unit 81. The pressure roller 82 is mainly provided. The fixing device 8 heat-fixes the toner image on the paper S by conveying the paper on which the toner image has been transferred between the heating unit 81 and the pressure roller 82. The paper S on which the toner image has been thermally fixed is discharged onto a paper discharge tray 22 by a paper discharge roller 23.

<Detailed configuration of process cartridge>
As shown in FIG. 2, the process cartridge 5 includes a photoconductor unit 6 and a developing unit 7. In the following description, the rotation axis direction of the photosensitive drum 61 and the rotation axis direction of the developing roller 71 corresponding to the left-right direction are simply referred to as “rotation axis direction”.

  The developing unit 7 includes a housing 70, a developing roller 71, and a pair of left and right seal members 76 (see FIG. 3).

  The housing 70 is a member that forms a storage portion 74 configured to store toner and supports the developing roller 71, the supply roller 72, the layer thickness regulating blade 73, and the like. Supplementally, the housing 70 rotatably supports the developing roller 71 and the supply roller 72, and the layer thickness regulating blade 73 is fixed by screws 79 as shown in FIG. Support. The housing 70 has, at its rear part, an opening 70A that is long in the rotational axis direction for supplying the toner in the container 74 to the developing roller 71 via the supply roller 72, and seals that are formed on both the left and right sides of the opening 70A. It has an installation part 70B.

  The developing roller 71 is a roller formed by covering the surface of a metal shaft shown with reference numerals omitted with conductive rubber, and is configured to carry toner on the outer peripheral surface 71B of the roller portion. Has been. The developing roller 71 is disposed so that the outer peripheral surface 71 </ b> B faces the opening 70 </ b> A of the housing 70, and is provided to be rotatable with respect to the housing 70.

  The seal member 76 is a member for suppressing toner leakage from between the both ends of the outer peripheral surface 71B of the developing roller 71 and the housing 70 in the rotation axis direction, and the both ends of the outer peripheral surface 71B of the developing roller 71 , Between the seal installation part 70 </ b> B of the housing 70. The left and right seal members 76 mainly have an elastic member 76A and a contact member 76B disposed between the elastic member 76A and the developing roller 71, respectively.

  The elastic member 76A is provided for the purpose of bringing the contact member 76B into close contact with the developing roller 71 by a restoring force when being crushed, and is made of an elastically deformable material such as urethane sponge. Further, the contact member 76B rotates the developing roller 71 smoothly, and for example, a fabric woven with Dyneema (registered trademark) SK60 manufactured by Toyobo Co., Ltd. for the purpose of reducing sliding resistance with the outer peripheral surface 71B. It is formed from a woven fabric such as a pile fabric, a non-woven fabric such as felt, a resin film or a resin tape. In addition, the specific structure of the seal member 76 is not specifically limited, For example, you may further have the adhesive member etc. for adhere | attaching the elastic member 76A to the seal installation part 70B.

  As shown in FIG. 4, the outer peripheral surface 71B of the developing roller 71 has a left and right contact area 71C that contacts the seal member 76 and an inner side of the left and right contact area 71C in the rotational axis direction, in other words, the left and right contact areas 71C. It has a non-contact area 71N that is not in contact with the seal member 76. The toner supplied from the supply roller 72 is carried on the non-contact area 71N.

  As shown in FIG. 2, the photoreceptor unit 6 includes a frame 60, a photoreceptor drum 61, a cleaning unit 64, and a toner return member 100 as an example of a developer return member.

  The frame 60 is a member that supports the photosensitive drum 61, the transfer roller 63, the cleaning unit 64, and the like. The frame 60 is configured such that the developing unit 7 is detachably mounted.

  The photosensitive drum 61 is a member in which a photosensitive layer is formed on the outer peripheral surface of a cylindrical drum body having conductivity, which is indicated by a reference numeral omitted, and toner is supplied from the developing roller 71 after charging and exposure. A toner image is formed. The photosensitive drum 61 is rotatably provided to the frame 60 at a position facing the developing roller 71 when the developing unit 7 is mounted on the frame 60 (photosensitive unit 6). As shown in FIG. 4, the photosensitive drum 61 is formed in a dimension longer than the outer peripheral surface 71 </ b> B of the developing roller 71 in the rotation axis direction.

  As shown in FIG. 5, the cleaning unit 64 is configured to remove deposits attached to the outer peripheral surface 61B of the photosensitive drum 61 after transferring the toner image, for example, paper dust generated from the paper S. This unit mainly includes a cleaning roller 64A, a recovery roller 64B, a scraping member 64C, and a frame 64D.

  The cleaning roller 64 </ b> A is a roller formed by coating the surface of a metal shaft that is not shown with a foamed elastic body such as a conductive sponge, and contacts the outer peripheral surface 61 </ b> B of the photosensitive drum 61. Are arranged. The cleaning roller 64 </ b> A is configured to adsorb a negatively charged adhering substance such as paper dust and remove it from the outer peripheral surface 61 </ b> B of the photosensitive drum 61 by applying a positive bias to a metal shaft. ing.

  In the present embodiment, the positively charged toner is basically not removed from the outer peripheral surface 61B of the photosensitive drum 61 by the cleaning roller 64A to which a positive bias is applied, but a part of the toner is cleaned with the photosensitive drum 61. When the roller 64A comes into contact, the roller 64A may adhere to the outer peripheral surface of the cleaning roller 64A and may eventually be collected in a storage unit 64E described later.

  As shown in FIG. 4, the roller portion of the cleaning roller 64 </ b> A is formed to be shorter than the outer peripheral surface 61 </ b> B of the photosensitive drum 61 and the outer peripheral surface 71 </ b> B of the developing roller 71 in the rotation axis direction.

  Returning to FIG. 5, the collection roller 64B is a metal roller and is disposed in contact with the outer peripheral surface of the cleaning roller 64A, and is configured to collect the deposits attached on the cleaning roller 64A. Further, the scraping member 64C is a member formed of a foamed elastic body such as a sponge, and is disposed in contact with the outer peripheral surface of the collection roller 64B, and is configured to scrape the adhered matter from the rotating collection roller 64B. Has been.

  The frame 64D is a member that supports the cleaning roller 64A, the recovery roller 64B, and the scraping member 64C, and a storage portion 64E for storing the deposits scraped off by the scraping member 64C is formed therein. Yes.

  As shown in FIGS. 5 and 6A and 6B, the toner return member 100 is a member made of fibers formed in a substantially rectangular sheet shape, and is in contact with the outer peripheral surface 61B of the photosensitive drum 61. The toner attached to the outer peripheral surface 61B of the photosensitive drum 61 is moved inward in the rotational axis direction by rotation of the photosensitive drum 61.

  Although detailed arrangement will be described later, as shown in FIG. 6A, the toner return member 100 is arranged at positions corresponding to both ends of the outer peripheral surface 61B of the photosensitive drum 61 in the rotation axis direction. Thus, it is attached to the frame 64D of the cleaning unit 64 via a flexible resin sheet-like member 65. As shown in FIG. 6B, the toner return member 100 is attached to the upper part of the front surface of the sheet-like member 65, and the lower part of the inner surface of the sheet-like member 65 is attached to the frame 64D. By being worn, it is attached to the frame 64D.

  FIG. 7 shows an enlarged view of the contact portion 110 that is a portion that contacts the outer peripheral surface 61B of the photosensitive drum 61 of the toner return member 100 disposed on the left side. The toner return member 100 disposed on the right side is substantially symmetrical with the toner return member 100 disposed on the left side, and is not shown.

  As shown in FIG. 7, the toner return member 100 is configured by weaving a plurality of first fibers 101 extending in the first direction and a plurality of second fibers 102 extending in the second direction so as to intersect each other. ing. Here, the first direction is the rotation direction of the photosensitive drum 61 indicated by the white arrow in FIG. 7 (more specifically, the portion facing the contact portion 110 in the outer peripheral surface 61B of the photosensitive drum 61). In the direction of the rotation axis toward the inside in the rotation axis direction, and the second direction refers to a direction toward the outside in the rotation axis direction from the upstream to the downstream in the rotation direction of the photosensitive drum 61. Say.

  As the weaving method of the fibers 101 and 102, for example, twill weave and satin weave are desirable. In FIG. 7, as an example, after the first fiber 101 gets over the two adjacent second fibers 102, it passes through the next two second fibers 102 adjacent to the two second fibers 102. Thus, the structure woven with twill is shown.

  A plurality of the first fibers 101 are provided adjacent to each other in the second direction in which the second fibers 102 extend, and the thickness direction of the toner return member 100 (the front side and the back side in FIG. 7). A plurality of them are also provided adjacent to each other. Similarly, a plurality of second fibers 102 are provided adjacent to each other in the first direction in which the first fibers 101 extend, and a plurality of second fibers 102 are provided adjacent to each other in the thickness direction of the toner return member 100. Yes.

  In the toner returning member 100, the first portion 103 where the first fiber 101 gets over the second fiber 102 and the second portion 104 where the first fiber 101 passes through the second fiber 102 in the contact portion 110 facing the photosensitive drum 61. In addition, it is woven so as to protrude toward the photosensitive drum 61 (front side in FIG. 7). Thus, the first portion 103 is a portion that actually contacts the outer peripheral surface 61B of the photosensitive drum 61.

  In the contact portion 110, the plurality of first portions 103 adjacent in the second direction are arranged to be inclined toward the inner side in the rotation axis direction from the upstream to the downstream in the rotation direction of the photosensitive drum 61. By projecting to the photosensitive drum 61 side from the portion 104, a convex portion 111 is formed that extends inward in the rotational axis direction from upstream to downstream in the rotational direction. In addition, the plurality of second portions 104 adjacent in the first direction are inclined and arranged so as to go inward in the rotation axis direction from the upstream to the downstream in the rotation direction of the photosensitive drum 61, and from the first portion 103. Since the recesses are also recessed, a recess 112 is formed that extends inwardly in the rotational axis direction from the upstream to the downstream in the rotational direction.

  A plurality of convex portions 111 and concave portions 112 are formed in a state of being alternately arranged along the rotation direction of the photosensitive drum 61. As a result, the toner return member 100 has a groove 115 formed by a concave portion 112 between adjacent convex portions 111 and extending toward the inner side in the rotational axis direction from the upstream side to the downstream side in the rotational direction of the photosensitive drum 61. A plurality of contact portions 110 are provided. For example, the groove 115 extends so as to form an angle θ of 45 ° or less with respect to the rotation axis 61 </ b> A of the photosensitive drum 61.

  As the toner returning member 100 as described above, for example, a woven fabric or a pile woven fabric made of Dyneema (registered trademark) SK60 manufactured by Toyobo Co., Ltd. can be used.

  Next, the arrangement of the toner return member 100 will be described. As shown in FIG. 4, the toner return member 100 is separately disposed at positions (left and right) corresponding to both ends of the outer peripheral surface 61 </ b> B of the photosensitive drum 61 in the rotation axis direction. Each toner return member 100 is disposed at a position where a part of the toner return member 100 overlaps the corresponding seal member 76 when viewed from the direction orthogonal to the rotation axis 61 </ b> A of the photosensitive drum 61. Specifically, each toner return member 100 is located at a position overlapping with both the contact area 71C and the non-contact area 71N of the developing roller 71 when viewed from the direction orthogonal to the rotation axis 61A of the photosensitive drum 61, that is, the contact area 71C. And the non-contact area 71N.

  More specifically, each toner return member 100 has a central portion in the rotation axis direction as viewed from a direction orthogonal to the rotation axis 61A of the photosensitive drum 61 and a boundary portion between the contact area 71C and the non-contact area 71N. They are arranged to be in the same position. In the present embodiment, the toner return member 100 is formed to have a slightly smaller dimension than the seal member 76 in the rotation axis direction.

  As shown in FIG. 5, the toner return member 100 is located downstream of the position where the toner image is transferred in the rotational direction of the photosensitive drum 61, that is, the position where the photosensitive drum 61 and the transfer roller 63 are in contact with each other. In addition, it is disposed upstream of the cleaning roller 64A.

Next, the effect of this embodiment comprised as mentioned above is demonstrated.
After the toner image is transferred to the paper S, some toner may remain on the outer peripheral surface 61B of the photosensitive drum 61 without being transferred.

  At this time, if the toner return member 100 is not provided, as shown as a comparative example in FIG. 8C, a part of the toner adhering to both end portions of the outer peripheral surface 61B of the photosensitive drum 61 is part of the photosensitive drum. By the rotation of 61 and the developing roller 71, the photosensitive drum 61 moves to the end of the outer peripheral surface 71B of the developing roller 71. Then, the toner moved to the end portion of the outer peripheral surface 71B enters between the end portion of the outer peripheral surface 71B and the seal member 76 by the rotation of the developing roller 71, and when this continues, the developing roller 71 and the seal member 76 are transferred. There is a risk that the toner will collect between the two and the sealing performance of the sealing member 76 will be reduced.

  As shown in FIGS. 8A and 8B, in the present embodiment, the toner return member 100 is provided, so that the contact portion between the outer peripheral surface 61B and the toner return member 100 is rotated by the rotation of the photosensitive drum 61. The toner that has entered the space 110 is guided by the groove 115 of the contact portion 110, and moves toward the inner side in the rotation axis direction of the photosensitive drum 61. Thereby, when the toner moves from the photosensitive drum 61 to the developing roller 71, it is possible to prevent the toner from adhering to the end portion of the outer peripheral surface 71B of the developing roller 71. Can be prevented from entering between.

  In particular, in this embodiment, since the toner return member 100 has the groove 115 in the contact portion 110, the toner can be moved along the groove 115 as described above, and the toner is efficiently moved inward in the rotation axis direction. be able to.

  In this embodiment, since the toner return member 100 is disposed at a position overlapping both the contact area 71C and the non-contact area 71N of the developing roller 71, the toner return member 100 causes the outer peripheral surface 61B of the photosensitive drum 61 to overlap. The toner adhering to the toner can be moved to a position corresponding to the non-contact area 71N. Accordingly, when the toner moves to the developing roller 71, it is possible to suppress the toner from adhering to the contact region 71C, so that the toner can be more reliably suppressed from entering between the developing roller 71 and the seal member 76. Can do.

  In this embodiment, since the toner return member 100 is disposed only at both ends of the photosensitive drum 61, the toner return member 100 is smaller than the case where one toner return member is provided longer in the rotation axis direction. The process cartridge 5 can be downsized. In other words, since the toner return member 100 can be arranged in a narrow space, compared to the case where one toner return member is provided longer in the rotation axis direction, the enlargement of the process cartridge 5 due to the provision of the toner return member 100 is suppressed. be able to.

  The toner that has moved from the photosensitive drum 61 onto the developing roller 71 (non-contact area 71N) is returned to the storage portion 74 via the supply roller 72 and is agitated with the toner in the storage portion 74 by the agitator 75. . Then, the toner is again supplied from the supply roller 72 to the developing roller 71, carried on the developing roller 71, and supplied to the photosensitive drum 61.

[Second Embodiment]
Next, a second embodiment will be described. In the embodiment described below, differences from the first embodiment will be mainly described in detail, and the same components as those in the first embodiment are denoted by the same reference numerals, and the same points as in the first embodiment. The description of is omitted as appropriate.

  As shown in FIG. 9, the cleaning roller 64A is an example of an adhering matter removing member in the present embodiment, and is disposed in contact with the outer peripheral surface 61B of the photosensitive drum 61 in the same manner as in the first embodiment. In this configuration, a deposit such as negatively charged paper dust adhered to the outer peripheral surface 61B of the photosensitive drum 61 after the toner image is transferred by the application of the bias is removed.

  The toner return member 100 is configured in the same manner as in the first embodiment, and is provided in a state where the toner return member 100 is in contact with both ends of the outer peripheral surface 61B of the photosensitive drum 61 one by one. In the present embodiment, each toner return member 100 is disposed downstream of the cleaning roller 64 </ b> A and upstream of the developing roller 71 in the rotational direction of the photosensitive drum 61. Each toner return member 100 is attached to the front surface of the front wall portion of the charger 62 formed by the frame 60 via a sheet-like member 65 by sticking or the like.

  Also in this embodiment, as in the first embodiment, the toner attached to the outer peripheral surface 61B of the photosensitive drum 61 by the toner return member 100 can be moved inward in the rotation axis direction. Can be prevented from adhering to the end of the outer peripheral surface 71B of the developing roller 71 when the toner moves to the developing roller 71. As a result, the toner can be prevented from entering between the developing roller 71 and a seal member (not shown in FIG. 9).

  By the way, when the toner remaining on the outer peripheral surface 61B of the photosensitive drum 61 is in a lump or the like, the lump of toner is pushed and spread by receiving a force between the photosensitive drum 61 and the cleaning roller 64A. May move to a position corresponding to the end of the outer peripheral surface 71B of the developing roller 71. In this case, in this embodiment, since the toner return member 100 is disposed on the downstream side in the rotation direction of the photosensitive drum 61, the toner can be returned to the inner side in the rotation axis line by the toner return member 100. Accordingly, even in the configuration in which the cleaning roller 64A is provided, it is possible to suitably suppress the toner from entering between the developing roller 71 and the seal member.

  The toner return member 100 may be provided at both the position described in the present embodiment and the position described in the first embodiment (see FIG. 5).

  As mentioned above, although main embodiment was described, this invention is not limited to the said embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of invention as follows.

  In the above-described embodiment, the cleaning roller 64A is configured to mainly remove deposits such as paper dust, but is not limited thereto. For example, referring to FIG. 5, as an example of the developer removing member, the cleaning roller 64A comes into contact with the outer peripheral surface 61B of the photosensitive drum 61, and the outer periphery of the photosensitive drum 61 after transferring the toner image. The toner remaining on the surface 61B may be removed by physical scraping or the like.

  In this case, as shown in FIG. 5, the toner return member 100 is located downstream of the position where the photosensitive drum 61 and the transfer roller 63 are in contact with each other in the rotational direction of the photosensitive drum 61, as in the first embodiment. In addition, it is desirable that it be disposed upstream of the cleaning roller 64A. According to this, since most of the toner can be removed by the cleaning roller 64A after the toner is moved inward in the rotation axis direction by the toner returning member 100 and collected, the amount of toner remaining on the photosensitive drum 61 itself is efficiently reduced. Can be reduced. Thereby, since the movement of the toner itself to the developing roller 71 can also be suppressed, it is possible to further suppress the toner from entering between the developing roller 71 and the seal member.

  The developer removing member and the deposit removing member are not limited to a roller-like member such as the cleaning roller 64A, and may be, for example, a blade-like member or a brush-like member.

  In the above-described embodiment, the toner return member 100 is formed in a size smaller than the seal member 76 in the rotation axis direction, but the present invention is not limited to this. For example, the toner return member may be formed in substantially the same size as the seal member in the rotation axis direction, or may be formed in a size larger than that of the seal member. In the embodiment, the toner returning member 100 is disposed at a position where a part of the toner returning member 100 overlaps the seal member 76 when viewed from the direction orthogonal to the rotation axis 61A of the photosensitive drum 61. However, the present invention is not limited to this. Instead, for example, when viewed from the direction orthogonal to the rotation axis of the photosensitive drum, all of them may be disposed at a position overlapping the seal member.

  In the above embodiment, the toner return members 100 are disposed at both ends of the outer peripheral surface 61B of the photosensitive drum 61, but the present invention is not limited to this. For example, the toner return member may be formed so as to be long in the direction of the rotation axis and to be in contact with substantially the entire width of the outer peripheral surface of the photosensitive drum.

  In the above-described embodiment, the toner return member 100 is a woven fabric formed by weaving fibers, but is not limited thereto. For example, as shown in FIG. 10A, the toner returning member 100 is a structure in which the fibers are hardened by compressing or adhering the fibers so that a groove 115 is formed in the contact portion 110 without weaving. It may be. Further, the toner return member 100 is not limited to a configuration made of fibers. For example, as shown in FIG. 10B, the toner return member 100 may be composed of a sheet-like resin or rubber having a groove 115 in the contact portion 110.

  In the above-described embodiment, the process cartridge includes the photosensitive unit 6 and the developing unit 7 that are detachable from each other, and is detachably attached to the main body housing 2 of the laser printer 1. It is not limited. For example, a process cartridge including the photosensitive unit 6 and the developing unit 7 that are detachable from each other includes a portion of the developing unit 7 where the developing roller 71 and the layer thickness regulating blade 73 are disposed, and a storage portion 74 (toner box). The structure which can be attached or detached from each other may be sufficient. Further, the process cartridge may have a non-detachable configuration in which the photosensitive unit 6 and the developing unit 7 are integrally formed. Further, the process cartridge may not be a cartridge that can be attached to and detached from the main body housing 2 of the laser printer 1.

  In the above embodiment, the laser printer 1 capable of forming only a monochrome image is exemplified as an image forming apparatus using the process cartridge of the present invention. However, the present invention is not limited to this, and for example, a printer capable of forming a color image. There may be. The image forming apparatus is not limited to a printer, and may be, for example, a copier or a multi-function machine including a document reading apparatus such as a flat bed scanner.

  In the above-described embodiment, the example in which the configuration using positively chargeable toner is described has been described. However, the present invention is not limited to this, and the present invention can also be applied to a configuration using negatively charged toner (developer). In this case, the polarity of the bias is opposite to that in the above embodiment.

5 Process cartridge 61 Photosensitive drum 61A Rotational axis 61B Outer peripheral surface 63 Transfer roller 64A Cleaning roller 70 Housing 71 Developing roller 71B Outer peripheral surface 71C Contact area 71N Non-contact area 76 Seal member 100 Toner return member 110 Contact part 115 Groove

Claims (7)

A housing configured to contain developer;
A developing roller provided rotatably on the housing and configured to carry a developer on an outer peripheral surface;
A seal member disposed between both ends of the outer peripheral surface of the developing roller in the rotation axis direction of the developing roller and the housing;
A photoconductive drum provided rotatably at a position facing the developing roller, and configured to form a developer image by supplying the developer from the developing roller;
A developer removing member configured to remove the developer remaining on the outer peripheral surface of the photosensitive drum after contacting the outer peripheral surface of the photosensitive drum and transferring the developer image;
As viewed from the direction perpendicular to the rotation axis of the photosensitive drum, at least a part is disposed at a position overlapping the seal member, and contacts the outer peripheral surface of the photosensitive drum and adheres to the outer peripheral surface of the photosensitive drum. And a developer returning member configured to move the developer toward the inner side in the rotation axis direction of the photosensitive drum ,
The developer returning member is disposed downstream of the position where the developer image is transferred and upstream of the developer removing member in the rotation direction of the photosensitive drum. Process cartridge.   The developer return member has a groove that extends in the rotational axis direction of the photosensitive drum from the upstream side to the downstream side in the rotational direction of the photosensitive drum at a portion that contacts the outer peripheral surface of the photosensitive drum. The process cartridge according to claim 1.   3. The process cartridge according to claim 1, wherein the developer return member is disposed at both ends of the outer peripheral surface of the photosensitive drum in a rotation axis direction of the photosensitive drum. 4. The outer peripheral surface of the developing roller has a contact area that contacts the seal member, and a non-contact area that is inside the contact area in the rotation axis direction of the developing roller and does not contact the seal member.
2. The developer returning member according to claim 1, wherein the developer returning member is disposed at a position overlapping both the contact area and the non-contact area when viewed from a direction orthogonal to a rotation axis of the photosensitive drum. Item 4. The process cartridge according to Item 3.   The process cartridge according to claim 1, wherein the developer returning member is made of a fiber.   The process cartridge according to claim 2, wherein the groove extends so as to form an angle of 45 ° or less with respect to the rotation axis of the photosensitive drum. A housing configured to store the developer, a developing roller rotatably provided on the housing and configured to carry the developer on an outer peripheral surface, and the rotation roller in the rotation axis direction A frame on which a developing unit is detachably mounted, comprising a seal member disposed between both ends of the outer peripheral surface of the developing roller and the housing;
  A photoconductive drum provided rotatably at a position facing the developing roller, and configured to form a developer image by supplying the developer from the developing roller;
  A developer removing member configured to remove the developer remaining on the outer peripheral surface of the photosensitive drum after contacting the outer peripheral surface of the photosensitive drum and transferring the developer image;
  As viewed from the direction perpendicular to the rotation axis of the photosensitive drum, at least a part is disposed at a position overlapping the seal member, and contacts the outer peripheral surface of the photosensitive drum and adheres to the outer peripheral surface of the photosensitive drum. And a developer returning member configured to move the developer toward the inner side in the rotation axis direction of the photosensitive drum,
  The developer returning member is disposed downstream of the position where the developer image is transferred and upstream of the developer removing member in the rotation direction of the photosensitive drum. Photoconductor unit.

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