| 摘要 |
PURPOSE: To prevent a failure in peeling and irregularities in an image by controlling a bias applied to a contact transfer member with a constant voltage, when the resistance value of the contact transfer member is smaller than a prescribed reference value. CONSTITUTION: It takes some time up to the arrival cf a transfer material started in carrying at a transfer position, in this time, a controller 73 issues a command to a power source 72, to control a transfer roller 28 with a constant current. The power source 72 monitors the value of a voltage applied by the control with the constant current and transmits the information to the controller 73. A resistance measuring means and a transfer bias control means which are incorporated in the controller 73 calculate the resistance value of the transfer roller 28 based on the information, compare the calculated resistance value with the prescribed reference value and switch the control when the transfer material reaches the position of the transfer roller 28 to the control with the constant voltage, when the calculated resistance value is lower than the prescribed reference value and to the control with the constant current, when the calculated resistance value is higher than the prescribed reference value. |
