| 摘要 |
PURPOSE:To perform steady electrification and transfer irrespective of a humidity change by the use of a contact-electrification method and, on the other hand, to remove toner on an electrifying member and a transfer member. CONSTITUTION:A voltage having the same polarity as that of electrified toner is supplied to an electrifying roller 5, which is in contact with a photoreceptor 1, by means of the positive voltage power source circuit 102 of a power source circuit 100, and the resistance value of the electrifying roller 5 is detected by a resistance value detecting circuit 106. At this time, the same voltage is supplied to a transfer roller 3 as well. The detected resistance value is compared with a reference value in a comparison circuit 107. Based on the result of the comparison, a control circuit 105 controls the output voltage of a negative voltage power source circuit 101 at the time of an image forming operation and supplies the voltage to the electrifying roller 5 and the transfer roller 3. At the time of the detection of the resistance value, toner sticking on the electrifying roller 5 and transfer roller 3 is transferred to the photoreceptor 1 by the application of the voltages having the same polarity of the electrified toner thereto, and the transferred toner is removed by a cleaning part. |
