JPS55101973A - Electrophotographic copying method and apparatus thereof - Google Patents

Abstract

PURPOSE:To improve transfer efficiency and make the separation and cleaning of transfer paper easy by generating the bias of the same polarity as that of toner in photoreceptor after development and transferring the toner by the action of the electric field between this and counter electrode. CONSTITUTION:The photoreceptor P which has two photoconductive layers 2, 3 on a conductive substrate 1 is distributed with the charges of different polarities in the both layers by corona dischargers 4, 5 of different polarities. Light images of the original 6 are then radiated thereto to form latent images which are next developed by black toner 7. Next, when the light having sensitivity only to the layer where the latent images are formed is radiated evenly, the negative charges of the 2nd photoconductive layer 3 discharge and the positive charges of the 1st conductive layer 2 are retained. Next, transfer paper 9 and counter electrode 10 are superposed and when the counter electrode 10 and the conductive substrate 1 of the photoreceptor P are connected and grounded, the toner 7 receives the force of the electric field going toward the counter electrode 10 and is pressed and transferred onto the transfer paper 1. This results in higher transfer efficiency and easier separation of transfer paper and cleaning.