JPS5636659A - Method for making plural copies - Google Patents

Abstract

PURPOSE: To keep almost constant the difference between the dark potential and the background potential of an electrostatic latent image in repeating only development and transfer during the time of making plural copies after forming the latent image using a phtoreceptor having an insulating layer on its surface.

CONSTITUTION: A photoreceptor is subjected to DC negative voltage with first charging corotron 2, to uniform exposure with lamp 3, to DC positive voltage with sencond charging corotron 4, and to imagewise exposure through slit 5. At that time, the residual potential on transparent insulating layer on photoreceptor 1 is shifted to a negative side by adjustement of the charge quantities of the first and second charging to render the difference between the dark potential and the background potential higher than that of the usual 1 cycle copy mode. The background potential corresponding to the light area of the original is adjusted by exposure quantity, developed and transferred. Alternatively, development bias voltage may be controlled in accordance with the potential of photoreceptor 1 at each copying, and the background potential is easily controlled by carrying out intermediate transfer.

COPYRIGHT: (C)1981,JPO&Japio