| 摘要 |
PURPOSE:To improve the performances of transfer and cleaning by carrying out constant current control with a voltage having the same polarity as the electrifying polarity of toner at the time of preceeding rotation and/or post- rotation. CONSTITUTION:A transfer roller 6 abuts on an image carrier 1 on the downstream side of a developing unit 4 viewed from the travelling direction of the image carrier 1, and a transfer part is formed. A transfer material 5 is fed to the transfer part while matching it with the timing when a toner image reaches the transfer part, and simultaneously the toner image of the image carrier side is transferred to the transfer material by the affection of an electric field which is formed on the transfer roller 6 after a transferring bias is applied by a transfer voltage generating circuit 7. The constant current control is carried out with the voltage having the same polarity as the electrifying polarity of the toner at the time of preceeding rotation and/or post rotating is carried out. Thus, efficient cleaning is always carried out in spite of the change in the environmental fluctuation of functions to return the toner from a transfer roller to a photosensitive body. An efficient transfer is always performed regardless of a condition where a transfer bias is applied when a transfer is performed. |
