Abstract: An electrostatic copying apparatus including detecting means for detecting the longitudinal size of the copying paper unit and a control means for operating the charging corona-discharge device only for a time period corresponding to the detected longitudinal size of the copying paper.

Abstract: A switch device for an electrostatic photographic copying machine having a reciprocally movable member reciprocating from a rest position and returning thereto during each copying operation of the copying machine, and a drive driving the movable member. The switch device has an actuating member movable relative to the copying machine body and is toward a non-operating position. An operating member engages with the actuating member for moving it to an operating position. A retaining device engages the actuating member for holding the actuating member in the operating position after it has been moved to the operating position. A switch actuating the drive for the movable member is engageable by the actuating member for actuating the drive means when the movable member is in the operating position and actuating the switch for deactuating the drive when the movable member is in the non-operating position.

Abstract: A method of and apparatus for synchronously transferring an original and a sheet of copying paper for electrostatic photoduplication. A paper feeding device feeds the sheets of copying paper one at a time until the front edge reaches a predetermined position at a front edge stop. The sheet of copying paper is held at the predetermined position on standby for a period of time, and then a paper transfer device transfers it to move the front edge to an exposure point. At the same time an original placed on a mount is moved from a stopping point in the cycle of movement of the mount to a position in which the leading edge of the original is at an irradiation point optically aligned with the exposure point. The period of time during which the copying paper is fed from the supply, held in the predetermined position, and then moved to the exposure position is equal to the time for moving the mount for the original from a predetermined point along the path of movement of the mount to the irradiation point.