| 摘要 |
PURPOSE: To provide a simply constituted inexpensive and compact device capable of obtaining a high-quality dense image without roughness, without generating the problem of the missing of an image or a color mixture, while keeping the image density of a solid black part, sufficiently high and moreover, and without necessory for reducing preventing a printing speed, in a multicolor image forming device using a multiple developing method. CONSTITUTION: A photoreceptor belt 1 having a substrate made of a translucent material is electrified by an electrifier 41, a black toner image is formed by a first image exposure E1 and development by a first developing unit 2 of a black developing unit and then, a second latent image is formed by the electrification with the electrifier 42 and an image exposure from the rear surface of the belt 1 by a second image exposing means 5. The latent image is developed with a two-component developer consisting of magenta nonmagnetic toner having <=10μm volume averaged grain size and magnetic grains having <=50μm weight averaged grain size, under a vibrating electric field in a noncontact developing method by a second developing unit 3 of a magenta developing unit, to form a magenta toner image on the belt 1. The triboelectric charge quantity of the black toner of the black toner image is larger than that of the magenta toner of the magenta toner image. |
