An image forming apparatus, including a casing, a toner cartridge, and a process cartridge, is provided. The toner cartridge detachably attached to the casing stores toner therein. The process cartridge detachably attached to the casing includes a developing unit and a drum unit. The developing unit includes a developer roller and a toner conveyer tube. The toner conveyer tube has a first opening, through which the toner from the toner cartridge is acceptable into the toner conveyer tube while the toner cartridge and the process cartridge are attached to the casing. The drum unit includes a photosensitive drum supporting the toner conveyer tube by contacting a circumferential surface of the toner conveyer tube. The developing unit is pivotable with respect to the drum unit with the toner conveyer tube and the drum unit being slidable on each other.

A process cartridge includes a photosensitive drum, a developing roller configured to develop a latent image on the photosensitive drum with toner, and a coupling member having a rotational axis, with the coupling member being operatively connected to the photosensitive drum. The coupling member includes a cylindrical portion having an outer surface and an inner surface that extends about the rotational axis of the coupling member, an arm portion extending from the inner surface of the cylindrical portion, and a projection projecting from the arm portion in a direction toward the rotational axis of the coupling member. The arm portion and the projection are movable relative to the inner surface.

A drum unit includes a photosensitive drum in a coupling member. The coupling member includes an engageable member having a driving force receiving portion which is capable of entering a recess of a driving shaft to receive a driving force for rotating photosensitive drum. The coupling member includes a holding member configured to hold said engageable member so as to be slidable at least in a radial direction of said drum unit.

A driving force transmission mechanism is a mechanism for transmitting rotational force of the second rotor having a driving-side coupling to a first rotor having a driven-side coupling. The driving-side coupling includes a body and a plurality of second engaging members engaging with first engaging members of the driven-side coupling, each of the plurality of second engaging members has at an abutting point on an abutting surface of a corresponding first engaging member a first inclined surface inclined so as to be away from a rotation axis of the body from a downstream side toward an upstream side in a rotation direction of the body.

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.

An image forming apparatus includes a casing, a toner cartridge, and a process cartridge. The toner cartridge detachably attached to the casing stores toner therein. The process cartridge detachably attached to the casing includes a developing unit and a drum unit. The developing unit includes a developer roller and a toner conveyer tube. The toner conveyer tube has a first opening, through which the toner from the toner cartridge is acceptable into the toner conveyer tube while the toner cartridge and the process cartridge are attached to the casing. The drum unit includes a photosensitive drum supporting the toner conveyer tube by contacting a circumferential surface of the toner conveyer tube. The developing unit is pivotable with respect to the drum unit with the toner conveyer tube and the drum unit being slidable on each other.

An image forming apparatus including: a restricting member; a driven gear including a portion to be restricted; a planetary gear mechanism including input portion to transmit a driving force from a driving source, output portion for transmitting the driving force to the driven gear; and a stopping member that is configured to stop rotation, which is oriented in a first rotation direction, and allow rotation of the portion to be stopped in a second rotation direction opposite to the first rotation direction, wherein when the input portion rotates in a first direction, the stopping member stops the rotation, and the output portion rotates the driven gear in a release direction opposite to the restriction direction, and when the rotation of the driven gear in the restriction direction is restricted and the input portion rotates to be oriented in a second direction opposite to the first direction.

A process cartridge for use 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 the process cartridge is dismountable from the main assembly in a direction substantially perpendicular to an axial direction of the driving shaft, the process cartridge includes i) an electrophotographic photosensitive drum having a photosensitive layer at a peripheral surface thereof, the electrophotographic photosensitive drum being rotatable about an axis thereof; ii) process means actable on the electrophotographic photosensitive drum; iii) a coupling member engageable with the rotational force applying portion to receive a rotational force for rotating the electrophotographic photosensitive drum, the coupling member being capable of taking a rotational force transmitting angular position for transmitting the rotational force for rotating the electrophotographic photosensitive drum to the electrophotographic photosensitive drum and a disengaging angular position in which the coupling member is inclined away from the axis of the electrophotographic photosensitive drum from the rotational force transmitting angular position, wherein when the process cartridge is dismounted from the main assembly of the electrophotographic image forming apparatus in a direction substantially perpendicular to the axis of the electrophotographic photosensitive drum, the coupling member moves from the rotational force transmitting angular position to the disengaging angular position.

A process cartridge includes a frame, a photosensitive drum supported by the frame, and a developing roller supported by the frame. A coupling is operatively connected to the photosensitive drum, with the coupling being rotatable about an axis thereof, and with the coupling being positioned (i) at a first end of the photosensitive drum, (ii) coaxial with the photosensitive drum, and (iii) at a side of the process cartridge. A helical gear is positioned at the side of the process cartridge, the helical gear being rotatable about an axis thereof, the helical gear having a plurality of teeth, with at least some of the teeth being exposed teeth that are uncovered by the frame and exposed to outside of the process cartridge. As measured in an axial direction of the photosensitive drum, at least a part of the exposed teeth of the helical gear is positioned farther from the second end of the photosensitive drum than a tip of a projection of the coupling is positioned from the second end of the photosensitive drum.

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.