Electrophotographic copying method with residual charge erasing step

摘要

A residual charge erasing step in the electrophotographic process in which a transparent conductor backed photoconductor layer positioned in virtual contact with a conductor backed dielectric layer is exposed to a light image while a first voltage is applied between the conductors to produce on the dielectric layer an electrostatic latent image, the erasing step which is applied after the transfer of the latent image includes positioning the photoconductor and dielectric layers in virtual contact, illuminating the full surface of the photoconductor layer and applying between the conductors a second voltage of a polarity opposite to the first voltage and whose value is (( chi a+ chi d)/ chi a)(312+6.2 chi a) wherein chi a and chi d are respectively the capacitive air gap equivalent thicknesses in microns between the virtually contacting layers and of the dielectric layer per se. Where residual charges of opposite polarities occurs such as where the dielectric member is precharged, erasing voltages of the above value are alternately applied at opposite polarities.