Patent ID: 6804475
Filing Date: 2004-10-12
Classification: G03G

Abstract:
A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, comprising:an electrophotographic photosensitive drum; a charging roller configured and positioned to electrically charge said electrophotographic photosensitive drum; a developing roller configured and positioned to develop an electrostatic latent image formed on said electrophotographic photosensitive drum; an input electrode extending along a longitudinal direction of said developing roller; an output electrode extending along the longitudinal direction of said developing roller; a grounding contact configured and positioned to electrically ground said photosensitive drum to the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said grounding contact being exposed at an end surface of a cartridge frame provided at one longitudinal end of said photosensitive drum and being disposed across an axis of said photosensitive drum; a charging bias contact configured and positioned to receive a charging bias voltage to be applied to said charging roller from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said charging bias contact being exposed and facing downwardly adjacent said one longitudinal end of said photosensitive drum when said cartridge is mounted to the main assembly of the apparatus; a developing bias contact configured and positioned to receive a developing bias to be applied to said developing roller from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said developing bias contact being exposed and facing downwardly adjacent said one longitudinal end of said photosensitive drum when said cartridge is mounted to the main assembly of the apparatus, and said developing bias contact being disposed at a side opposite from said charging bias contact with said photosensitive drum interposed therebetween with respect to a direction crossing a longitudinal direction of said photosensitive drum; an input electrical contact configured and positioned to receive an input bias to be applied to said input electrode from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said input electrical contact being exposed at the end surface of the cartridge frame provided adjacent said one longitudinal end of said photosensitive drum; and an output electrical contact configured and positioned to transmit, to the main assembly of the apparatus, an output produced on the basis of a value corresponding to an electrostatic capacity between said input electrode and said output electrode and an electrostatic capacity between said developing roller and said output electrode so that the main assembly of the apparatus can detect in substantially real time a remaining amount of the developer in said cartridge when said cartridge is mounted to the main assembly of the apparatus, said output electrical contact being exposed at the end surface of the cartridge frame.