EP2631718A2

image forming apparatus and photosensitive drum unit

Abstract

An electrophotographic photosensitive drum unit usable with a main assembly of an electrophotographic image forming apparatus, the main assembly including a driving shaft, to be driven by a motor, having a rotational force applying portion, wherein said electrophotographic photosensitive drum unit is mountable to the main assembly in a mounting direction substantially perpendicular to an axial direction of the driving shaft, said electrophotographic drum unit comprising: i) an electrophotographic photosensitive drum having a photosensitive layer at a peripheral surface thereof, said electrophotographic photosensitive drum being rotatable about an axis thereof; ii) a coupling member engageable with said rotational force applying portion to receive a rotational force for rotating said electrophotographic photosensitive drum, said coupling member being capable of taking a rotational force transmitting angular position for transmitting the rotational force for rotating said electrophotographic photosensitive drum to said electrophotographic photosensitive drum, and a pre-engagement angular position in which said coupling member is inclined away from the axis of said electrophotographic photosensitive drum from said rotational force transmitting angular position, wherein when said electrophotographic drum unit is mounted to the main assembly of the electrophotographic image forming apparatus in the mounting direction substantially perpendicular to the axis of said electrophotographic photosensitive drum, said coupling member moves from said pre-engagement angular position to said rotational force transmitting angular position.

EP2631718A2, drawing sheet 1
Sheet 1 of 109

Term

1.3 yearsto projected expiry

Projected expiry 25 December 2027, counted from filing; an application has no term until it is granted.

  1. Priority
  2. Filed
  3. Published
  4. Today
  5. Projected expiry

65 claims: 5 independent, 60 dependent

  1. 1
    An electrophotographic photosensitive drum unit usable with a main assembly of an electrophotographic image forming apparatus, the main assembly including a driving shaft, to be driven by a motor, having a rotational force applying portion, wherein said electrophotographic photosensitive drum unit is mountable to the main assembly in a mounting direction substantially perpendicular to an axial direction of the driving shaft, said electrophotographic drum unit comprising:i) an electrophotographic photosensitive drum having a photosensitive layer at a peripheral surface thereof, said electrophotographic photosensitive drum being rotatable about an axis thereof;ii) a coupling member engageable with said rotational force applying portion to receive a rotational force for rotating said electrophotographic photosensitive drum, said coupling member being capable of taking a rotational force transmitting angular position for transmitting the rotational force for rotating said electrophotographic photosensitive drum to said electrophotographic photosensitive drum, and a pre-engagement angular position in which said coupling member is inclined away from the axis of said electrophotographic photosensitive drum from said rotational force transmitting angular position, wherein when said electrophotographic drum unit is mounted to the main assembly of the electrophotographic image forming apparatus in the mounting direction substantially perpendicular to the axis of said electrophotographic photosensitive drum, said coupling member moves from said pre-engagement angular position to said rotational force transmitting angular position.
  2. 2
    An electrophotographic photosensitive drum unit according to Claim 1, wherein said coupling member is engaged with the driving shaft by moving from said pre-engagement angular position to said rotational force transmitting angular position.
  3. 3
    An electrophotographic photosensitive drum unit according to Claim 1 or 2, wherein in a state in which said coupling member takes said pre-engagement angular position, the axis (L2) of said coupling member is inclined toward downstream with respect to the mounting direction.
  4. 4
    An electrophotographic drum unit according to Claims 1 to 3, wherein in a state in which said electrophotographic drum unit is mounted to the main assembly, a part of said coupling member is behind the driving shaft as seen in the mounting direction, wherein when said electrophotographic drum unit is mounted to the main assembly, said coupling member is engaged with the driving shaft by said coupling member moving from said pre-engagement angular position to said rotational force transmitting angular position so as to permit the part of the coupling member to circumvent the driving shaft.
  5. 5
    An electrophotographic drum unit according to any one of Claims 1 to 4, wherein when said electrophotographic drum unit is mounted to the main assembly, said coupling member is engaged with the driving shaft by moving from said pre-engagement angular position to said rotational force transmitting angular position in response to movement of said electrophotographic drum unit in the mounting direction.
  6. 6
    An electrophotographic drum unit according to any one of Claims 1 to 5, further comprising a rotational force receiving member (151, 153, 155, 15151) for receiving the rotational force, said rotational force receiving member is provided on an end of said electrophotographic photosensitive drum, wherein said coupling member is coupled with said rotational force receiving member so that said coupling member is capable of taking said rotational force transmitting angular position and said pre-engagement angular position.
  7. 7
    An electrophotographic drum unit according to any one of Claims 1 to 6, further comprising an urging member (10634) for urging said coupling member in a direction of the axis (L1) of said electrophotographic photosensitive drum away from said electrophotographic photosensitive drum.
  8. 8
    An electrophotographic drum unit according to Claim 7, wherein said coupling member moves away from said electrophotographic photosensitive drum by an urging force of said urging member, when said coupling member moves from said pre-engagement angular position to said rotational force transmitting angular position.
  9. 9
    An electrophotographic drum unit according to any one of Claims 1 to 8, wherein said coupling member includes a rotational force receiving portion for engaging with the rotational force applying portion to receive the rotational force from the driving shaft, and a rotational force transmitting portion for transmitting the rotational force received through said rotational force receiving portion to said electrophotographic photosensitive drum.
  10. 10
    An electrophotographic drum unit according to Claim 9, wherein when said rotational force receiving portion receives the driving force for rotating said coupling member, said rotational force receiving portion is inclined with respect to the axis (L2) of said coupling member so as to receive a force toward the driving shaft.
  11. 11
    An electrophotographic drum unit according to Claim 9 or 10, wherein said coupling member includes a connecting portion between said rotational force receiving portion and said rotational force transmitting portion.
  12. 12
    An electrophotographic drum unit according to Claim 11, wherein said connecting portion includes a shaft that is formed along the axis (L2) of said coupling member.
  13. 13
    An electrophotographic drum unit according to any one of Claims 1 to 12, wherein said coupling member has a recess in which an axis (L2) of said coupling member extends, wherein said recess is over a free end of said driving shaft in the state in which electrophotographic drum unit is mounted to the main assembly.
  14. 14
    An electrophotographic drum unit according to Claim 13, wherein said recess includes an expanding portion expanding toward a free end of said coupling member.
  15. 15
    An electrophotographic drum unit according to Claim 14, wherein:the recess (150z) is constituted by a conical surface;or the recess (14150z) is constituted by two surfaces (14150f1;14150f2) which is expanded in a direction away from the coupling member axis (L2);or the recess has a divergent shape, a bell like shape, a cylindrical shape or a spherical shape;or the recess are constituted by a prularity of projections (12350d1, 12350d2;12350d3;12350d4) radically toward the free end of said coupling member.
  16. 16
    An electrophotographic drum unit according to any one of Claims 1 to 15, wherein a plurality of such rotational force receiving portions are provided on a phantom circle having a center on the axis (L2) of said coupling member at positions substantially diametrically opposite to each other.
  17. 17
    An electrophotographic drum unit according to Claim 16, wherein a plurality of said rotational force receiving portions are provided at regular intervals along a rotational direction of said coupling member, wherein the rotational force applying portion is provided at each of two positions which are diametrically opposite to each other with respect to the axis (L3) of the driving shaft.
  18. 18
    An electrophotographic drum unit according to any one of Claims 1 to 17, wherein said coupling member moves from said pre-engagement angular position to said rotational force transmitting angular position by receiving a force from said driving shaft as said drum unit is mounted to the main assembly.
  19. 19
    An electrophotographic drum unit according to any one of Claims 1 to 17, further comprising an another urging member (4159) for urging said coupling member from said rotational force transmitting angular position to said pre-engagement angular position.
  20. 20
    An electrophotographic drum unit according to any one of Claims 1 to 17, wherein said coupling member takes said pre-engagement angular position by its weight when said drum unit is mounted downwardly to the main assembly.
  21. 21
    An electrophotographic drum unit according to any one of Claims 1 to 20, wherein in a state in which said coupling member is positioned at said rotational force transmitting angular position, the axis (L2) of said coupling member is substantially coaxial with the axis (L1) of said electrophotographic photosensitive drum.
  22. 22
    An electrophotographic drum unit according to any one of Claims 1 to 21, wherein an angle between the axis (L2) of said coupling member and the axis (L1) of said electrophotographic photosensitive drum is about 20° to about 60°, when said coupling member takes said pre-engagement angular position.
  23. 23
    An electrophotographic drum unit according to any one of Claims 1 to 22, wherein said coupling member is provided to an end of said electrophotographic photosensitive drum and is capable of tilting relative to the axis (L1) of said electrophotographic photosensitive drum substantially in all directions.
  24. 24
    An electrophotographic drum unit according to any one of Claims 1 to 23, wherein the direction of mounting is a combination of straight lines or is a curvilinear.
  25. 25
    A process cartridge having an electrophotographic drum unit according to any of the preceding claims and process means actable on said electrophotographic drum, wherein said process cartridge is mountable to the main assembly.
  26. 26
    A process cartridge according to Claim 25, wherein said electrophotographic photosensitive drum is provided with a gear at the same end portion having said coupling member, wherein said gear is effective to transmit the rotational force received from the main assembly by said coupling member to a developing roller as said process means, and wherein said gear and said rotational force transmitting portion are overlapped with each other with respect to a direction of the axis (L1) of said electrophotographic photosensitive drum.
  27. 27
    A process cartridge according to Claim 26, wherein said gear includes a helical gear.
  28. 28
    A process cartridge according to Claim 26, wherein said gear includes a spur gear.
  29. 29
    A process cartridge according to any one of Claims 25 - 28, further comprising a guide member for guiding said coupling member toward said pre-engagement angular position.
  30. 30
    A process cartridge according to Claim 29, wherein said guide member is provided with a projection projecting from a frame of said process cartridge outwardly in the direction of the axis of said electrophotographic photosensitive drum.
  31. 31
    A process cartridge according to Claim 29 or 30, wherein said guide member is provided with a preventing portion for preventing movement of said coupling member toward a side opposite from said pre-engagement angular position with respect to said rotational force transmitting angular position.
  32. 33
    An apparatus according to Claim 32, wherein said coupling member is engaged with the driving shaft by moving from said pre-engagement angular position to said rotational force transmitting angular position.
  33. 34
    An apparatus according to Claim 32 or 33, wherein, in a state in which coupling member is positioned at said pre-engagement angular position, the axis (L2) of said coupling member is inclined toward downstream with respect to the mounting direction.
  34. 35
    An apparatus according to Claim 32 to 34, wherein in a state in which said electrophotographic drum unit is mounted to the main assembly, a part of said coupling member is behind the driving shaft as seen in a direction opposite the dismounting direction, wherein when said electrophotographic drum unit is mounted to the main assembly, said coupling member is engaged with the driving shaft by said coupling member moving from said pre-engagement angular position to the rotational force transmitting angular position so as to permit the part of the coupling member to circumvent the driving shaft.
  35. 36
    An apparatus according to any one of Claims 32 to 35, wherein when said electrophotographic drum unit is mounted to the main assembly, said coupling member is engaged with the driving shaft by moving from said pre-engagement angular position to said rotational force transmitting angular position in response to movement of said electrophotographic drum unit in the mounting direction.
  36. 37
    An apparatus according to any one of Claims 32 to 36, wherein said drum unit includes a rotational force receiving member (151, 153, 155, 15151) for receiving the rotational force, said rotational force receiving member is provided on an end of said electrophotographic photosensitive drum, wherein said coupling member is coupled with said rotational force receiving member so that said coupling member is capable of taking said rotational force transmitting angular position and said disengaging angular position.
  37. 38
    An apparatus according to any one of Claims 32 to 37, wherein said drum unit includes an urging member (10634) for urging said coupling member in a direction of the axis (L1) of said electrophotographic photosensitive drum away from said electrophotographic photosensitive drum.
  38. 39
    An apparatus according to Claim 38, wherein said coupling member moves away from said electrophotographic photosensitive drum by an urging force of said urging member, when said coupling member moves from said pre-engagement angular position to said rotational force transmitting angular position.
  39. 40
    An apparatus according to any one of Claims 32 to 39, wherein said coupling member includes a rotational force receiving portion for engaging with the rotational force applying portion to receive the rotational force from the driving shaft, and a rotational force transmitting portion for transmitting the rotational force received through said rotational force receiving portion to said electrophotographic photosensitive drum.
  40. 41
    An apparatus according to Claim 40, wherein when said rotational force receiving portion receives the driving force for rotating said coupling member, said rotational force receiving portion is inclined with respect to the axis (L2) of said coupling member so as to receive a force toward the driving shaft.
  41. 42
    An apparatus according to Claim 40 or 41, wherein said coupling member includes a connecting portion between said rotational force receiving portion and said rotational force transmitting portion.
  42. 43
    An apparatus according to Claim 42, wherein said connecting portion includes a shaft that is formed along the axis (L2) of said coupling member.
  43. 44
    An apparatus according to any one of Claims 32 to 43, wherein said coupling member has a recess in which an axis (L2) of said coupling member extends, wherein said recess is over a free end of said driving shaft in the state in which electrophotographic drum unit is mounted to said main assembly.
  44. 45
    An apparatus according to Claim 41, wherein said recess includes an expanding portion expanding toward a free end of said coupling member.
  45. 46
    An apparatus according to Claim 45, wherein:the recess (150z) is constituted by a conical surface;or the recess (14150z) is constituted by two surfaces (14150f1;14150f2) which is expanded in a direction away from the coupling member axis (L2);or the recess has a divergent shape, a bell-like shape, a cylindrical shape or a spherical shape;or the recess are constituted by a prularity of projections (12350d1, 12350d2;12350d3;12350d4) radically toward the free end of said coupling member.
  46. 47
    An apparatus according to any one of Claims 32 to 46, wherein a plurality of such rotational force receiving portions are provided on a phantom circle having a center on the axis (L2) of said coupling member at positions substantially diametrically opposite to each other.
  47. 48
    An apparatus according to Claim 47, wherein a plurality of said rotational force receiving portions are provided at regular intervals along a rotational direction of said coupling member, wherein the rotational force applying portion is provided at each of two positions which are diametrically opposite to each other with respect to the axis (L3) of the driving shaft.
  48. 49
    An apparatus according to any one of Claims 32 to 48, wherein said coupling member moves from said pre-engagement angular position to said rotational force transmitting angular position by receiving a force from said driving shaft as said drum unit is mounted to the main assembly.
  49. 50
    An apparatus according to any one of Claims 32 to 48, wherein said drum unit includes an another urging member (4159) for urging said coupling member from said rotational force transmitting angular position to said pre-engagement angular position.
  50. 51
    An apparatus according to any one of Claims 32 to 48, wherein said coupling member takes said pre-engagement angular position by its weight when said drum unit is mounted downwardly to the main assembly.
  51. 52
    An apparatus according to any one of Claims 32 to 51, wherein in a state in which said coupling member is positioned at said rotational force transmitting angular position, the axis (L2) of said coupling member is substantially coaxial with the axis (L1) of said electrophotographic photosensitive drum.
  52. 53
    An apparatus according to any one of Claims 32 to 52, wherein an angle between the axis (L2) of said coupling member and the axis (L1) of said electrophotographic photosensitive drum is about 20° to about 60°, when said coupling member takes takes said pre-engagement angular position.
  53. 54
    An apparatus according to any one of Claims 32 to 53, wherein said coupling member is provided to an end of said electrophotographic photosensitive drum and is capable of tilting relative to the axis (L1) of said electrophotographic photosensitive drum substantially in all directions.
  54. 55
    An apparatus according to any one of Claims 32 to 54, wherein the direction of mounting is a combination of straight lines or is a curvilinear.
  55. 56
    An apparatus according to Claims 32 to 55, wherein when said drum unit is mounted to the main assembly, said coupling member is moved to the second position by a force received from a portion of the main assembly before said coupling member is engaged with the driving shaft.
  56. 57
    An apparatus according to Claim 56, wherein the main assembly comprises a main assembly guide member (7130R1, 1130R1) for guiding said coupling member, wherein when said drum unit is mounted to the main assembly, said coupling member moves to said pre-engagement angular position by receiving a force from the main assembly guide member before said coupling member is engaged with the driving shaft.
  57. 58
    An apparatus according to Claim 56 or 57, wherein the main assembly comprising a slidable member (1131) elastically urged into a movement path of said coupling member when said drum unit is mounted to the main assembly, wherein when said drum unit is mounted to the main assembly, said coupling member is moved by a force received from said slidable member before said coupling member is engaged with the driving shaft.
  58. 59
    An apparatus according to any one of Claims 32 to 58, wherein said electrophotographic drum unit includes process means actable on said electrophotographic photosensitive drum to constitute a process cartridge.
  59. 60
    An apparatus according to Claim 59, wherein said electrophotographic photosensitive drum is provided with a gear at the same end portion having said coupling member, wherein said gear is effective to transmit the rotational force received from the main assembly by said coupling member to a developing roller as said process means, and wherein said gear and said rotational force transmitting portion are overlapped with each other with respect to a direction of the axis (L1) of said electrophotographic photosensitive drum.
  60. 61
    An apparatus according to Claim 60, wherein said gear includes a helical gear.
  61. 62
    An apparatus according to Claim 60, wherein said gear includes a spur gear.
  62. 63
    An apparatus according to any one of Claims 59 to 62, wherein said process cartridge comprises a guide member for guiding said coupling member toward said pre-engagement angular position.
  63. 64
    An apparatus according to Claim 63, wherein said guide member is provided with a projection projecting from a frame of said process cartridge outwardly in the direction of the axis of said electrophotographic photosensitive drum.
  64. 65
    An apparatus according to Claim 63 or 64, wherein said guide member is provided with a preventing portion for preventing movement of said coupling member toward a side opposite from said pre-engagement angular position with respect to said rotational force transmitting angular position.
Independent claims64