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.

An image forming apparatus includes: a housing; a cover; a developing cartridge; and a drum cartridge including a drum frame, a photosensitive drum, a pressing member configured to press the developing roller to the photosensitive drum in a state where the developing cartridge is mounted to the drum frame, and a lock lever, the drum cartridge being mountable to an inside of the housing in a state where the developing cartridge is mounted to the drum cartridge, wherein in a state where the cover moves from the closed position to the opened position, the lock lever moves from a locked position at which the developing cartridge is prevented from being demounted from the drum frame to a non-locked position at which the developing cartridge is allowed to be demountable from the drum frame.

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.

A replaceable imaging unit according to one example embodiment includes a photoconductor unit positioned at the front of a housing of the imaging unit. First and second alignment guides extend outward at the same height from first and second sides of the housing, respectively, on the photoconductor unit and run parallel to each other along a front-to-rear dimension of the housing. Each of the first and second alignment guides includes a front contact member at a front end thereof and a rear contact member at a rear end thereof. The front contact members are positioned further outward sideways than the rear contact members. Bottom surfaces of the front and rear contact members are unobstructed to permit the bottom surfaces of the front and rear contact members to sit on top of corresponding guide rails in the image forming device to control a vertical position of the imaging unit.

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 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.

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.

A replaceable imaging unit according to one example embodiment includes a photoconductor unit positioned at the front of a housing of the imaging unit. First and second alignment guides extend outward at the same height from first and second sides of the housing, respectively, on the photoconductor unit and run parallel to each other along a front-to-rear dimension of the housing. Each of the first and second alignment guides includes a front contact member at a front end thereof and a rear contact member at a rear end thereof. The front contact members are positioned further outward sideways than the rear contact members. Bottom surfaces of the front and rear contact members are unobstructed to permit the bottom surfaces of the front and rear contact members to sit on top of corresponding guide rails in the image forming device to control a vertical position of the imaging unit.

An image forming apparatus includes a casing, a photosensitive member, an exposing device, a cartridge attachable to and removable from the casing, a protruding portion protruding toward a removal path along which the cartridge is removed, and a guide portion disposed on the cartridge. The guide portion is configured to, when the cartridge is attached to the casing, guide a sheet toward the photosensitive member. The guide portion is movable relative to the cartridge between a guide position where the guide portion guides a sheet and a retracted position where the guide portion is retracted from the protruding portion when the cartridge is removed from the casing.

A replaceable imaging unit according to one example embodiment includes a photoconductor unit positioned at the front of a housing of the imaging unit. First and second alignment guides extend outward at the same height from first and second sides of the housing, respectively, on the photoconductor unit and run parallel to each other along a front-to-rear dimension of the housing. Each of the first and second alignment guides includes a front contact member at a front end thereof and a rear contact member at a rear end thereof. The front contact members are positioned further outward sideways than the rear contact members. Bottom surfaces of the front and rear contact members are unobstructed to permit the bottom surfaces of the front and rear contact members to sit on top of corresponding guide rails in the image forming device to control a vertical position of the imaging unit.