Conventionally, an electrophotographic image forming apparatus such as a laser printer and an LED printer is known. A developing cartridge is used for the image forming apparatus. The developing cartridge includes a developing roller for supplying toner. The developing cartridge in the prior art is inserted into a drawer unit. The drawer unit includes a photosensitive drum. In a case where the developing cartridge is inserted into the drawer unit, the photosensitive drum and the developing roller face each other. Further, the drawer unit to which the developing cartridge is attached is accommodated inside the image forming apparatus.
Further, the developing cartridge described in the prior art is inserted into the drum unit. The drum unit includes a photosensitive drum. In a case where the developing cartridge is inserted into the drum unit, the photosensitive drum and the developing roller face each other. Further, the drum unit including the developing cartridge attached to the drum unit is attached to the image forming apparatus.