| 摘要 |
PURPOSE:To eliminate the occurrence of image defect, which is caused by discharge at the front end of image, by detecting a current flowing in a transfer means, in an area where a toner image does not exist, and changing, according to the current, a voltage which is applied to the blank space of the front end of a recording medium. CONSTITUTION:A transfer roller 6 is pressed to the surface of a transfer drum 17 at the timing that a toner image does not exist on the intermediate transfer drum 17. A transfer-voltage control circuit 16 applies a preset voltage to the transfer roller 6, and detects a current flowing in the transfer roller 6. Based on this current, a proper voltage is applied to the transfer roller 6 by means of the transfer-voltage control circuit 16, and the toner image is transferred. For instance, when a voltage for satisfactory transfer is high due to a low temperature and humidity environment and the high resistance of the transfer system, the transfer voltage is controlled by increasing a voltage to be applied to the blank space of the front end of the recording medium 10, and when the environment in which the resistance of the transfer system is low, it is controlled at a low voltage. |
