DEVICE FOR CONTROLLING TONER DENSITY IN ELECTROPHOTOGRAPHIC COPYING MACHINE

摘要

PURPOSE:To eliminate the need for a pattern member for detecting density by forming the pattern image for detecting density to be formed when scanning of an original ends by utilizing the electric charge which is primarily and electrostatically charged on a photosensitive drum in the stage of non-exposing. CONSTITUTION:The point of the time when an irradiating means for exposing consisting of an exposing lamp H or the like of an exposing system for scanning an original surface stops is detected and a signal is emitted from a circuit 1 for detecting the time when the exposing lamp is put out. An erasing operation is stopped for a prescribed time by a delay circuit 2 upon receiving said signal. The optical density of the pattern image obtd. by developing the latent image formed by the irradiating means for exposing to a sensible image in a developing part is detected with a photosensor M and a toner supplying member Q is driven by a controller P according to said signal.