Electrographic copying machine

摘要

An electrographic copying machine in which an image projected on an original glass stand by a film projector is read out by a scanner and copied is provided with a color scanner including a CCD for reading out a projected image, a smoothing processing unit for averaging the tone data of pixels outputted from the color scanner every four pixels, a difference value totaling unit for totaling the difference values between the averaged tone data, and a control unit for performing focusing of the film projector so that the total of the difference values is maximum. The focusing of the projected image is automatically performed.