Electrophotographic image forming method

Abstract

An electrophotographic copying method in which there are employed a photosensitive member including a photoconductor layer backed by a conductive electrode and a dielectric layer backed by a conductive electrode comprises the steps of positioning the members with the layers in face-to-face virtual contact and while so positioned applying a voltage of a first polarity between the electrodes under dark conditions to cause gaseous discharges in the gaps between the layers and the charging of the dielectric layer and short circuiting the electrodes while illuminating the photoconductive layer until the electric field therein is zero, and then applying a voltage of reverse polarity between the electrodes while exposing the photoconducted layer to a light image to produce an electrostatic latent image thereof on the dielectric layer which is then separated from the photoconductor layer and the latent image developed and transferred to copy paper. Follower transfer of the developed image the dielectric layer is cleaned of residual toner and residual charges are removed by repositioning the dielectric layer in virtual contact with the photoconductor layer and alternately applying voltages of opposite polarities between the electrodes while illuminating the photoconductor layer. Equations setting forth the values of the applied voltages are given.