| 摘要 |
PROBLEM TO BE SOLVED: To prevent the deterioration of image quality caused by the fluctuation of the linear velocity of an image carrier caused by the contacting/separating action of a developer carrier by controlling the contacting/separating action of a contacting/separating member with/from the surface of the image carrier based on the contacting/separating action of the developer carrier. SOLUTION: A contacting/separating roller 19 capable of contacting with/ separating from the surface of a photoreceptor belt 1 is provided between the optical write-in position of the laying part of the belt 1 and the developing position of a developing device 5Y on the most upstream side. When the developing rollers 17 of all the developing devices 5 separate from the belt 1, the roller 19 comes in contact with the belt 1 by specified intruding amount. For example, when the actuation of BK is started and the developing roller 17BK of the developing device 5BK moves to the belt 1 side and starts to bite at the laying part of the belt 1, the roller 19 starts moving in a direction where it separates from the belt 1. While the developing device 5BK and the roller 19 are moving, they are controlled so that the sum of the instruding amount of the roller 17BK and that of the roller 19 may be the specified amount. |
