Abstract: A developing device for developing a latent image held on a latent image holding member by application of a developing agent, onto the latent image, which comprises a developing sleeve disposed in confrontation to the latent image holding member, a developer feeding device to feed the developer onto the surface of the developing sleeve, a regulating device to regulate thickness of a developer layer on the developing sleeve, and a shutter blade which is so provided as to be able to take a contact position with the surface of the developing sleeve and a withdrawal position away from the surface.

Abstract: A developing device for imparting triboelectrically charged developer to a surface to be developed includes a developer holding member disposed with a minute gap with respect to a latent image bearing member for holding and moving developer to a development station, a developer supply for supplying developer to the surface of the developer holding member, and a developer removing blade in contact with the developer holding member for removing the developer used for the development and remaining on the developer holding member, the blade having developer passage openings adjacent the portion which contacts the developer holding member to again impart removed developer to the developer holding means at a position downstream of the development station with respect to the movement of the developer and which is before the supply of developer is terminated at the developer supply.

Abstract: An A.C. corona discharging device for use in the process in which discharge and exposure are accomplished contemporaneously has insulating members disposed so as to surround the discharge wire or electrode and define the opening for projecting the image of an original. The potential gradient is increased, the discharge efficiency is improved and the flow of useless current which heretofore traveled through the shielding electrode is not encountered.