Abstract: An electrophotographic apparatus for forming any desired number of copies of a document from the same and single electrostatic charge latent image once formed on a photosensitive drum. The apparatus has a copy number set dial and a copy number counter for storing a desired copy number set by the dial. A control circuit for produces a load signal which serves to transfer the copy number set in the dial into the copy number counter. After the copy number has been transferred from the dial into the counter any desired copy number to be formed for a next document can be set in the dial. In a preferred embodiment the load signal is generated after a duplicating operation for a first copy has been initiated.

Abstract: A corona discharge device for electrographic apparatus which makes use of a drum-shaped photosensitive screen. The device is provided with a corona electric field establishing electrode extending in parallel with a corona discharge wire and supplied with an electric potential which is intermediate the electric potential of a field electrode and the electric potential of the corona discharge wire.

Abstract: An electrophotographic apparatus for forming or printing any desired number of copies of a document from the same and single electrostatic charge latent image comprisinga photosensitive member such as a photoconductive drum which is rotated at a constant velocity;a corona charger for uniformly charging the photosensitive drum;a document feeding device for advancing the document through an exposure-scanning portion at a constant speed;an optical device for projecting an image of the document at the exposure-scanning portion onto the drum to form an electrostatic charge latent image thereon;a developing device for developing the latent image with toner particles to form a toner image;a transferring device for transferring the toner image onto a record paper;a fixing device for fixing the toner image on the record paper to form a final copy;a clock pulse generator for producing clock pulses in synchronism with the rotation of the photosensitive drum;master and slave timing pulse generators for receiving the cloc

Abstract: An electrophotographic apparatus for obtaining a plurality of duplicated copies based on an image-like modulating information formed on a photosensitive member by one exposure comprises a casing having a sheet document copying area and a thick document copying area, a document sensing device for sensing the presence of a document at these copying areas, and a mechanism for controlling a step of forming the image-like modulating information on the photosensitive member by a signal generated from the document sensing device when the document is present on both or one of the copying areas and a copying completion signal.

Abstract: In an electrophotographic apparatus including a photosensitive screen drum there is produced a rotation signal each time the screen drum rotates one revolution beginning with a second revolution and the drum is stopped by an n.sup.th rotation signal, so that the drum is rotated through (n+l) revolutions when n copies are formed from the same document. During the first revolution of the screen drum, an electrostatic charge latent image is formed on the drum and during the successive n revolutions the latent image is repeatedly transferred to form n copies. A resetting operation of a copy number setting dial is initiated from the second revolution by the first rotation signal.

Abstract: A device for controlling a reverse time of a manuscript carriage, etc. for electrographic apparatuses is disclosed. The device comprises means for disengaging a forward movement electromagnetic clutch from a manuscript carriage or optical system driving mechanism and, after a lapse of time from the moment of disengaging the forward movement clutch from the manuscript carriage or optical system driving mechanism, for driving a backward movement clutch. The device is capable of effectively prevent the backward movement clutch and a carriage supporting plate, etc. from being subjected to heavy load and of effecting a reciprocal movement of the manuscript carriage or optical system in a smooth manner.

Abstract: A record sheet cutter control device which can cut a record sheet after a normal record sheet feeding operation has completely been stopped. The device comprises means for involving a difference in time between a signal for stopping the operation of a record sheet feed roller and a signal for starting the operation of a cutter.

Abstract: An electrographic apparatus comprising a photosensitive screen composed of an insulating layer, two electrically conductive layers coated on opposite sides of the insulating layer and a photosensitive layer coated on one of said electrically conductive layers, and a bias electric source connected between the two electrically conductive layers and producing, on a dielectric coated record sheet, an electrostatic latent image corresponding to an image to be reproduced is disclosed. The apparatus comprises means for adjusting a bias voltage supplied from the bias electric source and applied between the two electrically conductive layers.

Abstract: A device for controlling rotations of a photosensitive drum for electrographic apparatus. The device comprises a start button, a dial for setting number of copies to be reproduced, and means for rotating a photosensitive drum for turns corresponding to number of copies set beforehand plus 1 irrespective of setting said dial to positions corresponding to reproducing 1 copy and a plurality of copies.

Abstract: An electrographic apparatus which makes use of a screen drum composed of a mesh-shaped photosensitive screen. The apparatus comprises one corona discharge device, a corona voltage source circuit including a corona voltage source switch connected to an input side of said corona voltage source circuit and a polarity change-over switch connected between said corona voltage source circuit and said corona discharge device. A first step of uniformly charging said photosensitive screen and a second step of charging a dielectric coated record sheet with an electrostatic charge image corresponding to an image to be recorded are effected by one corona discharge device only.

Abstract: A corona charge device which can charge a medium being charged such as a photoconductive body or a record sheet provided for a conventional electrographic apparatus. The device comprises a corona discharge wire connected to a high voltage source and a grounded shield electrode surrounding the corona discharge wire and composed of an elongate rectangular closed vessel which is open at its bottom wall to define an opening. The transverse width of the opening is reduced by two opposed elongate insulating plates secured to the side walls of the vessel.