Patent ID: 8600264

Claim:
A developer cartridge detachably mountable on a tandem type photosensitive unit slidable to a drawn-out position and to a mounted position with respect to an image forming apparatus body, the developer cartridge comprising: a casing; a developer carrier rotatably supported on a first end portion of the casing for carrying a developer; a pair of upright portions arranged on and extending from flat surfaces of a second end portion of the casing and spaced apart from each other in the axial direction of the developer carrier, the pair of upright portions extending from the flat surfaces of the second end portion of the casing in a detaching direction of the developer cartridge; a coupling portion that is elastically deformable and extending in the axial direction of the developer carrier for coupling the upright portions with each other, wherein the coupling portion is entirely spaced apart from and does not contact, in the detaching direction and in a non-elastically deformed state, the flat surfaces of the second end portion of the casing from which the pair of upright portions extend; a notched portion notched from the second end portion of the casing toward the first end portion of the casing, wherein the notched portion is formed on the second end portion of the casing and opposite to the coupling portion; and an opposed portion opposed to and spaced apart from the coupling portion and the notched portion in the detaching direction on a part of the casing between the upright portions, wherein: the opposed portion is higher in rigidity than the coupling portion, the opposed portion is different from the notched portion, and the opposed portion is disposed above the notched portion in the detaching direction.