JPS5748739A - Electrophotographic method - Google Patents

Abstract

PURPOSE:To obtain a high-contrast copy free from texture contamination by performing the primary charging and opposite-polarity secondary charging of a photoreceptor, formed by providing a charge-applied layer and a dielectric layer on a conductive base and then by forming a photoconductive layer on the surface directly or with an intermediate layer interposed, in darkness. CONSTITUTION:On a conductive base 1, a charge-applied layer 2 is provided by using pigment, dye eutectic of dye and resin, photoconductive substance providing rectification, or an electron supplying or receiving compound. On the layer 2, a>= 10<12>cm dielectric layer (organic macromolecules or SiO2) 3 is formed. Further, a trasparent white intermediate layer 5 of macromolecules or SiO, MgF2, etc., on the layer 3 or a photoconductive layer 4 of an organic or inorganic photoconductive material is formed directly on the layer 3 without forming the layer 5. After primary chrging in darkness, the secondary charging of this photoreceptor with the opposite polarity is carried out and then picture exposure (shown by arrow) is performed. Consequently, the photoconductive layer 4 and dielectric layer 3 are charged differing in polarity. Therefore, clear positive-to-positive and positive-to-negative pictures are obtained with different kinds of toner 7 and 7' differing in polarity.