A process cartridge comprises a photosensitive drum and a developing roller. A coupling member is provided adjacent to one axial end of the developing roller. The coupling member includes a driven portion, and an intermediary portion configured and positioned to engage with the driven portion. The intermediary portion is also configured to be movable relative to the driven portion in a direction crossing the axis of the developing roller while maintaining engagement with the driven portion. The coupling member further includes a driving portion configured and positioned to receive a driving force for rotating the developing roller. The driving portion is also configured to engage with the intermediary portion, and to be movable relative to the intermediary portion in a direction crossing the axis of the developing roller while maintaining engagement with the intermediary portion.

To provide a process cartridge, a drum unit capable of receiving a driving force from the main assembly, and an image forming apparatus including the process cartridge. A cartridge is provided with a movable member having a driving force receiving portion. The movable member moves between an advanced position and a retracted position.

A gear includes a gear body to be attached to a distal end of a driving shaft in an axial direction of the driving shaft and including teeth each extending obliquely with respect to the axial direction, and a stopping portion included in the gear body and configured in such a manner as to allow the driving shaft to which the gear body is attached to move in a circumferential direction. When the driving shaft moves in the circumferential direction, the stopping portion is enabled to stop the gear body from moving in the axial direction, the stopping portion stopping the gear body by coming into contact with a portion of the driving shaft.

A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, includes a rotatable photosensitive drum; a rotatable developing roller configured to develop image formed on the drum, the developing roller being capable of contacting to and spacing from the drum; an urging force receiving portion configured to receive, from a main assembly side urging member, an urging force for spacing the developing roller from the drum; a cartridge side drive transmission member capable of the coupling with a main assembly side drive transmission member and configured to receive, from the main assembly side drive transmission member, a rotational force for rotating the developing roller; and a decoupling member capable of urging the cartridge side drive transmission member by the urging force received by the urging force receiving portion to decouple the cartridge side drive transmission member from the main assembly side drive transmission member.

A photosensitive member unit detachably mountable to a main assembly of an image forming apparatus, the image forming apparatus including a first main assembly side helical gear portion and a second main assembly side helical gear portion which are coaxially rotatable, the photosensitive member unit includes a photosensitive member rotatable about a rotational axis thereof; a first unit side helical gear portion for meshing engagement with the first main assembly side helical gear portion; and a second unit side helical gear portion for meshing engagement with the second main assembly side helical gear portion, wherein a twisting direction of a tooth of the second unit side helical gear portion is the same as the twisting direction of a tooth of first unit side helical gear portion, wherein a helix angle of the tooth of the second unit side helical gear portion is larger than a helix angle of the tooth of the first unit side helical gear portion, and wherein the first unit side helical gear portion and the second unit side helical gear portion are rotatable in a state in which the first unit side helical gear portion is in meshing engagement with the first main assembly side helical gear portion, and the second unit side helical gear portion is in meshing engagement with the second main assembly side helical gear portion.

An example image forming apparatus includes a frame, a first shaft supported by the frame, and a first coupler. The first coupler includes a body coupled to one end of the first shaft and a first protrusion protruding from the body in an axial direction of the first shaft, the first protrusion having a first surface and a second protrusion protruding from the first surface. The second protrusion is to lock with a groove to mount a cartridge on the frame, the first shaft is to provide a rotational force in a first rotational direction to rotate the second protrusion of the first coupler and to insert the second protrusion into the groove to lock with the cartridge, and the first surface of the first protrusion of the first coupler is to contact a second surface to transmit the rotational force to the second coupler in the first rotational direction.

An image forming apparatus includes a development cartridge having a developing roller. The developing roller includes a roller body, and a shaft to pass through a central axis of the roller body. A coupling structure is disposed at an end part of the shaft, is movable from a first position to a second position, and includes a first coupling piece and a second coupling piece. Positions of the first coupling piece and the second coupling piece are maintained with respect to one another by a static frictional force between surfaces of the first coupling piece and the second coupling piece to hold the coupling structure in the first position. When a predetermined force overcomes the static frictional force, the first coupling piece and the second coupling piece disengage from one another to allow the coupling structure to move from the first position to the second position.

An image forming apparatus includes a cartridge including a portion-to-be-positioned, and an apparatus main body on which the cartridge is mounted in a mounting direction. The apparatus main body includes a positioning portion and a regulating portion. The positioning portion positions the cartridge by engaging with the portion-to-be-positioned. The regulating portion is provided on an upstream side of the positioning portion in the mounting direction. The cartridge includes a portion-to-be-regulated provided on an upstream side of the portion-to-be-positioned in the mounting direction. The portion-to-be-positioned engages with the regulating portion before engaging with the positioning portion, to regulate movement of the cartridge in the direction orthogonal to the mounting direction. The portion-to-be-regulated engages with the regulating portion before the portion-to-be-positioned engages with the positioning portion, to regulate movement of the cartridge in the direction orthogonal to the mounting direction.

A cartridge includes a photosensitive drum and a casing rotatably supporting the photosensitive drum. A coupling is operatively connected to the photosensitive drum so as to be capable of transmitting a driving force toward the photosensitive drum. The coupling includes a main body, a movable portion movable relative to the main body of the coupling between a first position and a second position, and a projection configured to move in a circumferential direction of the coupling relative to the main body of the coupling in response to movement of the movable portion from the first position to the second position.

A developing cartridge and an electronic imaging apparatus, where the developing cartridge is detachable installed in the electronic imaging apparatus, and includes a cartridge, a power reception member, a rotary member and an activation member; the cartridge includes a first side wall and a second side wall provided opposite to each other along a first direction, where a power reception member is located at the first side wall, a rotary member is installed between the first side wall and the second side wall, one end of the rotary member is provided with a first gear, and the other end of the rotary member is provided with a second gear, an activation member is located at the second side wall; and the activation member includes a movable member and a trigger part provided at the movable member.