JPS57125951A - Electrophotographic recording method - Google Patents

Abstract

PURPOSE:To obtain two color recording of a high grade by applying initial electrostatic charging on a photoreceptor then exposing a positive image and a negative image in superposition thereon and at the same time, performing electrostatic chatging of the charge of the reversed polarity from that of the initial charge thence forming the latent image having potential of 3 value levels through full surface exposure. CONSTITUTION:A transparent insulation layer is laminated on a photoconductive layer on a photosensitive drum 11. First, it is subjected to positive corona charging then to negative corona charging, and at the same time to superposed exposure of copying exposure P which is a positive image and printing exposure N which is a negative image, thence it is subjected to full surface exposure L. After this, with the bias of a developing device 31 as a plus value, the image is developed with a black toner having negative polarity, then the black toner sticks on the image part of the negative printing exposure. Further, with a developing device 32 biased negative, the image is developed with a blue toner, whereby the image of the positive copying exposure is obtd. Next, the polarities of the toners are unified to negative by a force electrostatic charging Corotron 23; thereafter, corona transfer of plus is executed with a corona charger 24, whereby the good recording of two colors is obtained on recording paper 40.