Patent ID: 7565092

Claim:
A developer cartridge that is attachable to and detachable from a photosensitive body cartridge that includes a photosensitive member, the developer cartridge comprising: a frame including a first side wall and a second side wall, the first side wall and the second side wall extending substantially in a length direction; a developer supplying section for supplying a developer to the photosensitive body cartridge, the developer supplying section extending in a width direction substantially perpendicular to the length direction from the first side wall to the second side wall and including a developer roller; a developer housing section for housing the developer, the developer housing section extending in the width direction from the first side wall to the second side wall, and the developer housing section including: an open end at which the developer housing section adjoins the developer supplying section; and a closed end substantially opposite from the open end, the closed end including an exterior surface extending from a substantially bottommost portion of the developer housing section to a top portion of the developer housing section, the exterior surface extending in the width direction; and at least one engaging portion, the engaging portion extending outwardly from the exterior surface of the developer housing section; wherein when the developer cartridge is detachably attached to the photosensitive body cartridge, the engaging portion engages with the photosensitive body cartridge to press the developer roller towards the photosensitive member.