Method for effecting registration for a copying apparatus

Claim 1

In an electrophotographic copying apparatus having a magnification ratio varying device, and in which a seamless photosensitive drum member (11) in motion and at any rotational position is exposed to an optical image of an original, by slit exposing, to form an electrostatic latent image thereon, with the scanning velocity of the original being adjustable in accordance with the selected magnification ratio, an improvement for effecting registration, consisting essentially of: first detection means having only a single stationary detector (20), for detecting the leading end of the original in one of a path of travel of the original and a path of travel of a movable optical system, to produce one detection signal; means (18) responsive only to said one detection signal connected to said first detection means to deliver a copy sheet to the photosensitive member (11) only after the lapse of a predetermined period of time following the production of said one detection signal, which predetermined period of time is varied in conformity with the selected magnification ratio; time period varying means (32,39) connected to said responsive means for varying the predetermined period of time; and other means responsive to a second signal (52) to perform other operations necessary for effecting electrophotographic copying other than said copy sheet delivering operation.