METHOD FOR ADJUSTING CONTRAST OF ELECTROPHOTOGRAPHIC PICTURE

PURPOSE:To extend a density reproducing range to reproduce gradations of an original picture faithfully and well by charging the surface of an image carrier with a certain potential lower than the potential of uniform charging before development after irradiation of an image light. CONSTITUTION:The surface of a photosensitive body 1 consisting fundamentally of a conductive substrate 11 and a photoconductive layer 12 is charged uniformly by a corona charger 2. When light I of an original image is irradiated on a photosensitive body 1, carrier pairs 13 proportional to the quantity of light are generated in the photoconductive layer 12, and plus carriers out of them are migrated to the photoconductive layer 12 and are flowed to the conductive substrate 11, and discharging is caused between minus carriers and the plus electric charge on the surface of the photosensitive body 1. The next process is started just after exposure of the light I. That is, the surface of the photosensitive body 1 is charged by a corona charger 3 having a grid G to which a bias V1(