| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure capable of suppressing re-transfer occurring during passage of a patch through a primary transfer part in a configuration in which detection of the patch as a toner image for adjustment is carried out on an intermediate transfer belt as an intermediate transfer body and on a photoreceptor drum as an image carrier, respectively.SOLUTION: In a primary transfer part of the most downstream black station, switching from a normal bias to a second bias for passage is performed during patch formation. On the other hand, in the primary transfer part of each station of magenta and cyan downstream a yellow station, the switching from the normal bias to a first bias for passage is performed during patch formation. Then, a positive polarity is increasingly set in an order of a potential of a nonexposure part, the second bias for passage, the first bias for passage, and the normal bias. |
