US Patent 10042321 Drum cartridge

A drum cartridge, comprising: a photosensitive drum; and a drum frame having a first state where a developing device is attached to the drum frame, the developing device including a developing roller, and a second state where a developing cartridge is detachably attachable to the drum frame, the developing cartridge including a developing roller and a developing frame which stores toner, wherein, in the first state, a toner cartridge is detachably attachable to the developing device.