| 摘要 |
PURPOSE:To prevent paper trace, back stain, etc., by impressing a transfer bias, which has an opposite polarity from toner and is lower than a bias impressed in the case of feeding paper to a transfer member when a paper is not fed. CONSTITUTION:A transfer bias impressed when a paper is not fed has the opposite polarity from that of toner, and is set smaller than a bias impressed when paper is fed. After a paper is fed, primary electrification is turned off; developing biases 5 and 6 are turned off when the trailing part of the electrifying part on the surface of a photosensitive drum 1 reaches a developing part, and the transfer bias 8 is turned off when the falling part of the electrifying part on the surface of the photosensitive drum 1 reaches a transfer part. Since the bias impressed when a paper is not fed is smaller than the transfer bias impressed when paper is fed, transfer memory is small; additionally, the reversely polar toner is not transfered to a transfer roller 2 since the transfer roller 2 has the same polarity as the reversely polar toner being a small amount of toner. This prevents paper trace, back stain of a transfer paper, and etc. |
