| 摘要 |
PURPOSE: To improve image quality by performing the attaching/detaching control of a secondary transfer roller and a cleaner while preventing the staining of the secondary transfer roller and surely removing remaining toner with the cleaner, and also, to prevent the occurence of an electromagnetic noise due to the voltage impression on the secondary transfer roller. CONSTITUTION: The length L2 of a 1st area from the primary transfer part to the secondary transfer part of an intermediate transfer belt 40 is set equal to or exceeding the length of the area of the toner image primarily transferred to the belt 40. And, only when the toner image exists within the 1st area A, such a control is performed that the secondary transfer roller 47 and a cleaning blade 51 are permitted to come into press-contact with the belt 40, or to separate from the belt 40. And also, a switching operation by a developing device switching motor for placing a prescribed developing device opposite to a photoreceptor drum 10 is performed at a timing capable of bringing the roller 47 and the cleaning blade 51 into press-contact with the belt 40, or separating the roller 47 and the blade 51 from the belt 40. |
