JPS6429876A - Controller for electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To control precisely a position with only one sensor by disposing an optically driving motor encoder on the driving motor of an optical system, counting optical encoder pulses, judging the position of said system and controlling it. CONSTITUTION:In the optical system 4 composed of a lens sending original images to an exposure part 5 and a mirror group, the optical system driving motor is equipped with the optically driving motor encoder. Since a distance by which the optical system moves per pulse of said encoder is constant, the position of the optical system is determined by counting the number of encoder pulses even if speed of the optical system is varied. A home position sensor is placed to serve as a reference position, and only said sensor detects the optical position. Thus one sensor alone can detect the moving position of the optical system and control it surely.