Electrostatic copying apparatus

In an electrostatic copying apparatus including a housing, a photosensitive member, an original-support mechanism including a transparent plate on which to place an original document to be copied, a charging corona-discharge device for applying corona discharge to the photosensitive member, an optical unit including an original-illuminating lamp for projecting the image of the original document onto the photosensitive member, and a copying paper transfer unit for transferring a copying paper through a predetermined transfer passage extending through a transfer zone;

• the improvement comprising detecting means for detecting the longitudinal size of the copying paper being transferred by the transfer unit, means for scanningly moving one of the original-support mechanism and at least a part of the optical unit toward the other to cause the image of the original document to be scanned and projected onto the photosensitive member, and control means for operating the charging corona-discharge device only for a period of time which corresponds to the detected longitudinal size of the copying paper said control means including actuation starting means for starting the actuation of the charging corona-discharge device simultaneously with, immediately before, or immediately after, the starting of the scanning movement of the one of the original-support mechanism and at least a part of the optical unit from a scanning movement starting position, and actuation stopping means which when the one of the original-support mechanism and at least a part of the optical unit has made a scanning movement from the scanning movement-starting position by a distance substantially corresponding to the longitudinal size of the copying paper detected by the copying paper size detecting means, stops the actuation of the charging corona-discharge device.