| 摘要 |
PROBLEM TO BE SOLVED: To suppress a variation in speed of an endless belt with a small number of components compared with a case of holding the belt from the inside and outside thereof to apply a conveyance load.SOLUTION: An intermediate transfer belt 21 is laid over a plurality of rollers. One of the plurality of rollers is a driving roller that drives to rotate the intermediate transfer belt 21. The intermediate transfer belt 21 is in contact with four primary transfer rollers 15 (Y, M, C, and K) during a full-color image forming mode. Meanwhile, the intermediate transfer belt 21 is in contact only with one primary transfer roller 15K during a monochrome image forming mode, and separated from the primary transfer rollers 15 (Y, M, and C). During the monochrome image forming mode, the intermediate transfer belt 21 is in contact on its rear face with a braking force acting member 159 that causes braking force to act on the belt 21 so as to cause braking force to act on the intermediate transfer belt 21.SELECTED DRAWING: Figure 4 |
