Electrostatic copier with additional corona discharge unit - for eliminating copy faults due to residual charges on photoconducting drum

摘要

In electrophotographic copying in a copier using a rotatable endless photosensitive part in known manner by (a) neutralising the charges on the light sensitive part by the incidence of light thereon (b) charging up the photosensitive part (c) projecting an optical image corresponding to the pattern of an original on the charged light-sensitive part to form an electrostatic image of the original thereon, specifically a first step in the prodn. of a uniform charge distribution on the light sensitive part is carried out before neutralising the charge, and preferably comprises the uniform charging up of the light sensitive part, particularly by a corona discharge device. Gives a copy of higher quality free from spots and fog.