Abstract: In an electrophotographic printing apparatus which includes a photosensitive drum having a photoconductive layer on its surface, a primary charger for uniformly charging the surface of the photosensitive drum, a developing agent tank for containing powder developing agent, a developing system for supplying the powder developing agent supplied from the developing agent tank to the surface of the photosensitive drum, and a cleaner for removing the powder developing agent from the surface of the photosensitive drum. The photosenstivie drum, the primary charger, the developing system, a container for the developing agent tank, and the cleaner are integrally mounted to a support member to form an image-forming cartridge. This cartridge is removably mounted to a main body of the electrophotographic printing apparatus, and the developing agent tank is removably mounted in the container of the cartridge.

Abstract: A developing apparatus includes restriction member disposed midway of a route through which developer is delivered from a hopper to a supply roller. The restriction member restricts the amount of the developer to be supplied to the supply roller. The amount of developer supplied from the supply roller to a developing roller is limited by the provision of the restriction member. The developer on the surface of the developing roller is thinned or doctored by a developing blade and develops an electrostatic latent image on a carrier.

Abstract: An aqueous solution containing 0.1 g/l or more of piperidine or a derivative, 100-500 g/l of sulfuric acid, 10-50 g/l of hydrogen peroxide and 0.5 g/l or more of phosphoric acid is used for treating the surface of copper or copper alloy used in manufacturing of printed circuit.

Abstract: An electrophotographic printer comprises an access cover for opening and closing an upper opening of a cavity in an enclosure, a rotatable head holder supported at one adjacent to the inner surface of the access cover, an optical print head provided on the inner surface of the head holder, and a process cartridge containing a photosensitive drum provided so that it can be inserted and removed through the upper opening. The optical print head may have holes provided at both ends thereof, and the process cartridge may have pins which are engageable with the holes on the optical print head, thereby to facilitate alignment between the optical print head and the photosensitive drum.