A development system for an image forming apparatus includes a photosensitive drum having a drive plate to receive a driving force to rotate the photosensitive drum. The drive plate is provided on an end of the photosensitive drum. The development system also includes a developing roller having a clutch mechanism to dampen a force generated when the clutch mechanism engages the drive plate of the photosensitive drum. The clutch mechanism is provided on an end of the photosensitive drum.

A process cartridge includes a frame, a photosensitive drum supported by the frame, a developing roller supported by the frame, and a coupling operatively connected to the photosensitive drum. A helical gear is positioned at the side of the process cartridge, the helical gear being rotatable about an axis thereof. A stopper is positioned at the side of the process cartridge, with the stopper having a surface extending in an axial direction of the photosensitive drum and facing the axis of the photosensitive drum. As measured in an axial direction of the photosensitive drum, at least a part of exposed teeth of the helical gear is positioned farther an end of the photosensitive drum than a tip of the projection of the coupling is positioned from the end of the photosensitive drum.

Provided is an Oldham coupling having a play in a rotational direction and being capable of transmitting a driving force.

An Oldham coupling 1 includes a developing drive gear 99 that is a first hub, a drive coupling 89 that is a second hub, and an intermediate member 3 that transmits a driving force between the developing drive gear 99 and the drive coupling 89. The developing drive gear 99 includes a protruded portion 99a that is fitted to a recessed portion 3a of the intermediate member 3 to transmit a driving force between the developing drive gear 99 and the intermediate member 3. When seen in a rotational axis direction of the Oldham coupling 1, the shape of a protruded portion 89a is a substantially rhombic shape.

An example cartridge may be detachably attached to a main body of an image forming apparatus. The cartridge includes a rotation member and a driven coupler to receive a rotation force to rotate the rotation member. The driven coupler includes a power transmission member connected to the rotation member, an extension member extending from the power transmission member and including an outer diameter portion, a hollow portion, and a through portion, a protrusion member located at the hollow portion and movable between a protrusion position for receiving the rotation force and a retreat position, a switching member inserted into the hollow portion and movable between first and second positions for locating the protrusion member at the protrusion position and the retreat position, respectively, and an elastic member to apply an elastic force to the switching member in a direction for location at the second position.

A cartridge couplable to a printing apparatus may include a driver coupler movable in a first direction toward an engaging position to engage with a power driver of the printing apparatus to drive the cartridge and a power transfer member including a power transfer part to transfer power moving the driver coupler in the first direction toward the engaging position, as the power transfer part moves in a second direction different from the first direction.

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.

A process cartridge includes a photosensitive drum; a developing roller; a developer supplying roller, provided in contact with the developing roller; a driving force receiving portion provided at a shaft end of the supplying roller; a first driving force transmitting portion; a second driving force transmitting portion; flexible sheets provided adjacent to an engaging portion between the first portion and the second portion to intermittently contact the second portion with rotation of the second portion, wherein a rotational direction of the roller is opposite to that of the roller, and a peripheral speed of the roller is larger than that of the roller.

A gear unit for transmitting a rotational force to a rotatable member carrying developer and to which a coupling member is mountable. The gear unit includes a hole portion which opens outwardly in a direction along a rotational axis of the cylinder gear and which has an opening capable of accommodating the spherical portion, a groove portion which continues from the hole portion and which is capable of accommodating the projected portion, and a limiting portion for limiting inward movement of the spherical portion in the direction along the rotational axis of the gear. A closing member is provided for partially covering the opening of the hole portion and mounted to the gear to limit outward movement of the spherical portion in the direction along the rotational axis of the gear. The closing member is constituted by a plurality of independent pieces.

A developing cartridge includes: a developing roller; a coupling for rotating the developing roller; a shaft; and a clutch. The developing roller is rotatable about a first axis extending in an axial direction. The coupling is rotatable about a second axis extending in the axial direction. The shaft rotatably supports the coupling. The clutch is rotatable together with the coupling about the shaft in a case where the coupling rotates in a first rotational direction. In a case where the coupling rotates in a second rotational direction opposite to the first rotational direction, the clutch engages with a portion of the shaft and the clutch and the coupling do not rotate.

In a cartridge structure employing an inclinable coupling member engaging with a rotational force transmitting portion of an electrophotographic image forming apparatus, the coupling member is unable to engage with the rotational force transmitting portion of the electrophotographic image forming apparatus when the mounting and dismounting direction and the developing/spacing direction relative to the electrophotographic image forming apparatus of different from each other. Under the circumstances, a coupling lever contacting and retracting relative to the coupling member in interrelation with the mounting and dismounting operation of a developing cartridge B1, and a coupling spring for the coupling lever to apply an urging force to the coupling member are provided.