To prevent a first toner image at an upstream image forming station from being retransferred at a downstream image forming station while suppressing transfer failure of a toner image from a photoreceptor drum to an intermediate transfer belt (ITB) in a structure having a plurality of image forming stations.
A post exposure device is disposed between a developing device and a primary transfer part around the photoreceptor drum at a downstream image forming station. And, the absolute value of the surface potential Vr in this region is decreased lower than the absolute value of the potential Vd charged by a charging roller by exposing a region in which the second toner image is not formed around the surface of the photoreceptor of the downstream image forming station by the post exposure device. Thus, the retransfer contrast 1TrReVc may be decreased while securing the transfer contrast 1TrVc at the downstream image forming station and the above problems may be solved.
Yoshiro Sakamoto
Takashi Daejeon