ELECTROPHOTOGRAPHIC PHOTOSENSITIVE DRUM UNIT

摘要

PURPOSE:To prevent vibration sound of a photosensitive drum and dielectric breakdown of a photosensitive layer by contact electrostatic charge by providing this drum unit with a photoreceptor formed with the photosensitive layer on a stainless steel substrate specified in surface roughness and an electrostatic charging device in contact with this photoreceptor. CONSTITUTION:An electrostatic charging roll 2 is disposed on the surface of the photosensitive drum 1 in such a manner that this roll comes into contact therewith. DC voltage superposed with an AC components is impressed on the core material 3 of this electrostatic charging roll 2 formed with a layer consisting of a conductive elastic material for the core material 3. The conductive substrate made of a stainless steel pipe is used for this photosensitive drum 1 and its surface roughness Rmax is adjusted to >=2.0mum by grinding. The photosensitive layer is formed on such conductive substrate. Further, the surface roughness Rmax is preferably >=0.1mum in order to prevent generation of interference fringe patterns to be generated at the time of irradiation with a laser beam. As a result, the photosensitive layer less generates abnormal discharge and the discharge breakdown of the photosensitive layer is prevented when the photosensitive drum is subjected to contact electrostatic charge. The vibration sound generated by contact or sliding is thus prevented.