| 摘要 |
PROBLEM TO BE SOLVED: To enhance a latent image contrast and density gradient and to widen a color space expressible with a multicolor image formed by color mixture in multiplex image formation. SOLUTION: A black image is formed at a position A, images of a mixed color of black and red are formed at positions B and C and a red image is formed at a position D, on a photoreceptor. A first image exposure has light quantities EB1 , EB2 and EB3 at the positions A, B and C respectively. At the positions B and C, surface potentials after an exposure are set to be 200V and 250V for instance respectively. After a black toner image is formed, the output of a second electrifier is made higher than that at the time of executing the above-mentioned nonmixed color image forming process, to electrify a black toner image part, and a nonimage part, of a background on the photoreceptor up to about 800V (d). After second electrification, the difference ΔV between the surface potentials at the positions B and C in the figure (e) is made large, so that a stuck toner quantity can be increased. |
