| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus that suppresses a trouble that when a plurality of developing rollers are started to rotate, a large amount of developer is accumulated at a position opposite to the developing rollers and image carriers, even when developing devices of a multistage developing system are used.SOLUTION: An image forming apparatus can execute "a control mode (low-speed driving start mode)" of, when starting rotation of two developing rollers 23a1 and 23a2, rotating the two developing rollers 23a1 and 23a2 at the number of rotations R1 (linear velocity N1) smaller than a predetermined number of rotations R0 (linear velocity N0) during a normal developing step for a predetermined time T1, and subsequently rotating the two developing rollers 23a1 and 23a2 at the normal number of rotations R0.SELECTED DRAWING: Figure 4 |
