Developing or cleaning unit for an electrophotographic printing machine

Claim 1

A processing station for use in an electrophotographic printing machine for developing an electrostatic latent image recorded on a flexible photoconductive member having at least a photoconductive layer deposited on a substantially transparent conductive layer or cleaning material therefrom, wherein the improvement includes: means, positioned closely adjacent to the flexible photoconductive member on the side of the photoconductive layer defining a cleaning or developing zone, for transporting magnetically single component magnetic particles into the zone to clean material from the region of the flexible photoconductive member in the zone or to deposit the single component magnetic particles on the region of the flexible photoconductive member in the zone when developing the latent image; means for maintaining the flexible photoconductive member at a pre-selected tension of sufficient magnitude so that at least the single component magnetic particles on said transporting means deflects the flexible photoconductive member to wrap the flexible photoconductive member about an extended region of the exterior surface of said transporting means to form an extended cleaning or developing zone between said transporting means and the flexible member; means, positioned on the side of the transparent layer of the flexible photoconductive member, for illuminating the zone during cleaning; and means for controlling said transporting means to position the region of said transporting means having a strong metallic field opposed from the zone during cleaning and the region of the said transporting means having a weak magnetic field opposed from the zone when the latent image is being developed.