Patent ID: 8346126

Claim:
An image forming apparatus comprising: an apparatus body; a tandem photosensitive drum unit which holds a plurality of photosensitive drums to be in parallel with each other, and is movably mounted in the apparatus body along an array direction of the photosensitive drums; a developing cartridge which is provided for each of the photosensitive drums, supports a developing roller for supplying developer to the corresponding photosensitive drum, and is configured to be detachably mounted in the tandem photosensitive drum unit; a translation member which is provided in the apparatus body to be movable linearly in the array direction; a supporting shaft which is provided on each of the developing cartridges; and a movable member which is rotatably supported by the supporting shaft, and provided at a position where the translation member abuts along a linear movement thereof, wherein the movable member includes: a main body which extends in a direction orthogonal to the supporting shaft, and is rotatably supported by the supporting shaft at a first end portion of the main body in a longitudinal direction thereof; an input portion which is provided at a second end portion of the main body opposite to the first end portion, and to which a pressing force is input by the translation member with the linear movement of the translation member after abutting the input portion; an abutting portion which is provided at a middle portion between the first and second end portions of the main body, and abuts the tandem photosensitive drum unit while the movable member rotates about the supporting shaft by the input of the pressing force to the input portion; and an operating portion which is configured to apply a force to the supporting shaft for moving the developing cartridge from a first position where the developing roller contacts the photosensitive drum to a second position where the developing roller is separated from the photosensitive drum as the movable member is rotated with the abutting portion as a fulcrum by the input of the pressing force to the input portion while the abutting portion abuts the tandem photosensitive drum unit.