| 摘要 |
PURPOSE:To prevent image quality from being deteriorated by preventing developer from being uselessly consumed and to surely mesh a driving gear on a driving source side with a driven gear on a developing device side. CONSTITUTION:Before the developing device for cyan 2a arrives at a developing position A, a developing bias is impressed on a developing roll 3a. Under such a state, the developing device 2a is moved to the position A by rotating a rotating body 5. When the developing device 2a arrives at the position A, the driven gear 4a and the driving gear 6 are meshed. By driving and rotating the roll 3a by driving a driving motor 11 and connecting an electromagnetic clutch 12, a developing process is started. After the developing process is finished, the clutch 12 is discriminated and the rotation of the roll 3a is stopped. By driving and rotating the rotating body 5, the developing device 2a is separated from the position A. After the developing device 2a is separated from the position A, the developing bias impressed on the roll 3a is released. |
