Dual mode correction of image distortion in a xerographic printing apparatus.

摘要

Correction of image distortion in a reproduction machine due to vibrational or speed distortions in or between a moving photoreceptor (22) and an imaging device (30) projecting raster lines on the photoreceptor as it moves past the imaging device, utilizing an encoder (60) for sensing the speed of the photoreceptor and also the relative vibrational motion between the photoreceptor and the imaging device and providing electrical signals to a signal separator separating the electrical signals into lower and higher frequency signals (74,76); and a servo motor (24) for driving the photoreceptor and compensating for the lower frequency increases or decreases in the speed of the photoreceptor, the servo motor being driven by the separated lower frequency signals; and an optical system (90) for pivoting the projected raster lines to compensate for the image distortions which are of the higher frequencies, the optical system (90) being driven by the higher frequency signals from the signal separator. <IMAGE>