| 摘要 |
PROBLEM TO BE SOLVED: To obtain an excellent image in which toner scattering and toner filming are eliminated even though a monochromatic image and a multicolor image coexist for both-side image forming by executing transfer current control which is different according as a toner image is monochromatic or multicolor at the time of transferring a rear side image to an intermediate transfer body. SOLUTION: The toner image on the rear side image formed on a photoreceptive drum 10 is transferred on the intermediate transfer body 14a by a primary transfer unit 14c provided on the rear side of the intermediate transfer body 14a. The layer thickness of the toner of the multicolor image is larger than that of the monochromatic image in the toner image of the rear side image. Thus, transfer voltage or a transfer current value is set to be higher when the back face image is multicolor than when it is monochromatic. When constant transfer current control is executed, a transfer current I (A) has the relation of: I (A) [multichrome (back)]>I (A) [monochrome (back)] depending on whether the back surface image is monochromatic or multicolor. |
