JPS5729076A - Powder image transfer type electrophotographic copying method - Google Patents

Abstract

PURPOSE:To facilitate high speed copying and prevent the occurrence of the changes in sensitivity, memory effect, etc. by subjecting to a specific previous history sensitizing process repeatedly >=2 times then to changing and exposure, on a photoreceptor made by forming a photoconductive layer contg. Cd and Se and an insulation characteristic protecting layer successively on a conductive backing. CONSTITUTION:A photosensitive drum 1 laminated with a photoconductive layer consisting of dispersing a photoconductive material contg. Cd and Se in a binder resin and, in some cases, further an insulation layer thereon is subjected to the 1st sensitization process upon starting of the drum 1 to the same polarity as that at the formation of electrostatic latent images by a corona charger 8 for powder image transfer. Thence, it is subjected to the 2nd sensitization process by charging and exposing with a sensitizing unit 13 consisting of a subcharger 14 and a suberaser 15. Thereafter, it is subjected to main charging 2, and exposure 5 of an image 3, followed by developing with a developing device 6 and transferring of the image on transfer paper 7. In this way, the high speed copying is facilitated by making sensitivity more than twice higher with the same photoreceptor, and the occurrence of a change in sensitivity after discontinuance and the image contamination by the memory effect of the drum 1 are prevented.