| 摘要 |
PROBLEM TO BE SOLVED: To suppress the decrease of transfer efficiency and to prolong the life of an intermediate transfer body by previously storing the current value or voltage value of the intermediate transfer body, at which the transfer efficiency for a recording medium of the intermediate transfer body becomes highest with respect to each of plural surface resistance values of the intermediate transfer body and controlling a current or a voltage supplied to the intermediate transfer body, so as to make the transfer efficiency highest with respect to each surface resistance value. SOLUTION: A secondary transfer low-current source 21 is connected to a secondary transfer roller 8. In a secondary transfer process, the secondary transfer roller 8 brings the recording medium into press-contact with an intermediate transfer drum 6 and the low-current source 21 causes the current to flow in the intermediate transfer drum 6, with the secondary transfer roller 8. A voltage detector 22 detects the voltage value applied to the drum 6. A current controller 23 controls a constant current outputted by the constant current source 21, so as to obtain the transfer efficiency of the drum 6 being most suitable for the recording medium 7, with respect to the voltage value detected/ outputted by the voltage detector 22, based on this voltage value. |
