JPS56113150A - Electrophotographic copying method - Google Patents

Abstract

PURPOSE:To obtain a copy having less ground stains and improve the durability of the apparatus by forming the electrostatic latent images corresponding to the light images of a negative original by the use of a photoreceptor covering its photoconductive layer with a transparent insulation layer then reversal-developing the same with the toner of the same polarity as that of the electrostatic latent images. CONSTITUTION:A photoconductive layer 102 and a transparent insulation layer 103 are provided on a conductive substrate 101. The surface of the layer 103 of this photoreceptor 1 is uniformly + charged to, for example 900V. Next, light is irradiated to a negative original 3 whereby the surface potential of the photoreceptor 1 of the area (b) corresponding to the nonimage part is made 800V and the surface potential of the photoreceptor 1 of the area (a) corresponding to the image part is made 300V. Next, the developer in a two-component type developer vessel 404 is biased by applying bias voltage of 700V to a developing electrode 401 from a bias power source 402, whereby the + charged toner T images are formed on the photoreceptor 1. Thence, these are transferred and fixed to transfer paper 5 by a transfer device 12. Next, the photoreceptor 1 is cleaned and is repeatedly used. The image density is good, and the sticking of the carriers K on the nonimage forming part B and the occurrence of the insulation breakdown of the photoreceptor 1 are obviated.