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 drive device includes a drive source, a drive train including a plurality of drive transmitters, and a positioning member. The drive train transmits a driving force of the drive source to a driven member. The plurality of drive transmitters include a first group of the drive transmitters and a second group of the drive transmitters. The drive source and the first group of the drive transmitters together serve as an integrated unit attached to one side of a facing member facing a side panel of an image forming apparatus. The integrated unit includes a positioning object. The second group of the drive transmitters is supported by a shaft disposed on another side of the facing member. The positioning member includes a positioning portion with which the positioning object is engaged on the one side or said another side of the facing member.

A developing cartridge includes a casing, a developing roller rotatable about an axis extending in a first direction, a developing memory having an electrical contact surface, an agitator, an agitator gear rotatable about an agitator axis together with the agitator, a holder holding the electrical contact surface, and a plate movable between a first position and a second position in a second direction crossing the first direction relative to the casing. The holder is movable relative to the casing in a third direction crossing the first and second directions between a retracted position and an advancing position. The holder is movable from the retracted position to the advancing position in response to a movement of the plate from the first position to the second position. The plate is positioned farther away from the developing roller than the agitator gear and the holder are in the second direction.

A photosensitive member unit includes a photosensitive member, a transfer roller, a mounting portion capable of mounting a development unit including a development roller, a first gear and a second gear each provided at one end of the photosensitive member in an axial direction of the photosensitive member, and a third gear provided at one end of the transfer roller in an axial direction of the photosensitive member and configured to engage with the second gear. The first gear, the second gear, and the third gear are helical gears. A direction in which helical teeth of the first gear are inclined is opposite to a direction in which helical teeth of the second gear are inclined, and the direction in which the helical teeth of the first gear are inclined matches a direction in which helical teeth of the third gear are inclined.

A cartridge detachably mountable to a main assembly of an image forming apparatus includes a photosensitive member unit including a photosensitive drum; a sheet configured to remove a deposited matter from a surface of the drum, the sheet being in contact with the surface of the drum at an end portion of the drum with respect to a rotational axis direction of the member; and a developing unit detachably mounted to the member unit, the developing unit including a developing roller configured to supply toner to the drum, and a storage portion configured to store the deposited matter removed from the surface of the drum by the sheet.

The image forming apparatus includes a drum cartridge having a photosensitive drum and a drum drive input member; a developing cartridge configured to be movably mounted to the drum cartridge, the developing cartridge comprising a developing roller disposed so as to face the photosensitive drum and a developing drive input member; a drum drive transmission member configured to engage with the drum drive input member and configured to transmit drum driving force to the drum drive input member while permitting a positional gap of the drum drive input member within a predetermined range; and a developing drive transmission member configured to engage with the developing drive input member and configured to transmit developing driving force to the developing drive input member while permitting a positional gap of the developing drive input member within a predetermined range.

A developing cartridge includes a developing roller, a casing, and a cam. The developing roller is configured to be positioned at a contact position where the developing roller is in contact with a photosensitive drum of a drum cartridge. The developing roller is also configured to be positioned at a separated position where the developing roller is separated from the photosensitive drum. The cam is movable relative to the casing between a first position and a second position. A portion of the developing cartridge is in contact with the drum cartridge and functions as a pivot center so that the casing and the developing roller are pivotally moved about the pivot center when the cam is moved from the first position to the second position.

A process cartridge includes a photosensitive drum and a gear portion having gear teeth configured to receive a driving force from outside of the process cartridge. The gear portion includes an exposed portion exposed to outside of the process cartridge. A shortest distance from an axis of the photosensitive drum to a tooth tip of the exposed portion of the gear portion measured along a direction perpendicular to the axis of the photosensitive drum is no less than 90% and no more than 110% of a radius of the photosensitive drum.

A cartridge for a main assembly of an electrophotographic image forming apparatus, wherein the main assembly includes a rotatable driving coupling member including a driving force transmitting portion for transmitting a driving force and a driving side abutment, wherein the cartridge is demountable in a direction substantially perpendicular to a rotational axis of the driving coupling member, includes a rotatable driven coupling member including a driving force receiving portion for receiving the driving force, and a driven side abutment to be abutted by the driving side abutment, the driven coupling member being slidable in a predetermined direction which is substantially parallel with a rotational axis of the receiving coupling member; wherein at least one of the driving side abutment and the driven side abutment is inclined so that the driven coupling member is retractable away from the driving coupling member in the predetermined direction by a force received by driven side abutment from the driving side abutment, and wherein a distance between the rotational axis of the driven coupling member and the abutment of the receiving abutment is not more than a distance between the rotational axis of the driven coupling member and the driving force receiving portion.

In an image formation device, a driven gear is coupled to a far end portion in a unit inserting and withdrawing direction of a rotary fixing member or a rotary pressure member of a fixing unit. A driving gear is provided in a far end portion of a fixing unit housing part and engages with the driven gear when the fixing unit is housed in the fixing unit housing part. The driving gear and the driven gear are formed so that a transmission force transmitted from the driving gear to the driven gear in a mutual engagement position has a component so directed as to horizontally press the fixing unit against columns making a pair. The fixing unit as housed in the fixing unit housing part is pressed by the transmission force against the columns and positioned in a direction orthogonal to the unit inserting and withdrawing direction.