Abstract: A developing device including a developing roller opposed to a photoconductor and rotatably mounted to a developing case of the developing device. A blade mounting surface is formed in an outer wall of the developing case, that is opposed to the photoconductor, and a blade holder, a blade and a supporting plate, that are laminated with each other, are mounted to the blade mounting surface of the developing case. A part of the blade opposite to a part of the blade sandwiched between the blade holder and the supporting member is elastically bent so as to contact an outer circumferential surface of the developing roller, and seal members are arranged at least along an edge of a longitudinal side of the blade holder at the side of the developing roller and along an edge of another longitudinal side of the blade holder at the opposite side of the developing roller, respectively, so as to increase airtightness of gaps between the blade holder and the outer wall of the developing case.

Abstract: A novel process cartridge for an image forming apparatus such as for example an electrophotographic copying machine, an image forming apparatus using the novel process cartridge, and a method of manufacturing the novel process cartridge. The cartridge includes a photoconductor unit in which a photoconductor drum is rotatably mounted and a developing unit in which a developing roller is rotatably mounted. A first pair of side plates are formed on the photoconductor unit and rotatably supports both end portions of the photoconductor drum. A second pair of side plates are formed on the developing unit and rotatably supports both end portions of the developing roller. A first pair of pin inserting holes are formed on the first pair of side plates of the photoconductor unit. A second pair of pin inserting holes are formed on the second pair of side plates of the developing unit.