JPS5625751A - Formation of electrostatic image freed of black image - Google Patents

Abstract

PURPOSE:To enable an electrostatic image with its black image erased to be easily formed, by forming on a substrate an electrostatic image reverse in polarity corresponding to the black image of an original, and overlaying this image on the other image. CONSTITUTION:Photoconductive photosensitive layer 1A on the outer circumference of photosensitive drum 1 is positively charged, and exposed to the light image from original 5 transmitted through dichroic filter 9, resulting in forming electrostatic positive images corresponding to black image B and red image R, because filter 9 obstructs transmission of red light. On the other hand, photosensitive layer 2A of photosensitive drum 2 is negatively charged, and exposed to the reflected light from filter 9, resulting in forming an electrostatic negative image corresponding to black image B of original 5 on layer 2A because filter 9 functions as a transmitter of the red light. Then, layer 1A of drum 1 and layer 2A of drum 2 are contacted with each other, thus permitting the positive and negative charges of the black image to be neutralized and the electrostatic image corresponding to only red image R to be formed on layer 1A.