| 摘要 |
PURPOSE:To prevent the adhesion of developer to a transfer device, even upon occurrence of recording sheet jam. CONSTITUTION:The existence of recording sheets at both upstream and downstream sides of a transfer position C is detected by a photo-resist sensor 7 and a delivery sensor 8. In addition, feed current to a transfer roller 20 is detected by an ammeter 15 and a control section 18 detects the arrival of a recording sheet to the transfer position C, according to the predetermined change of the detected current. Furthermore, the control section 18 detects sheet jam at both upstream and downstream sides of the position C, according to timing for current change detection. In the case of jam at the upstream side, the control section 18 stops the operation of an exposure device 3 and causes the rotation of a photo-sensitive drum 1 by a number corresponding to an angle EC, after connecting a reverse voltage power supply to the transfer roller 20. Then, the control section 18 stops operation. In the case of jam at the downstream side, the control section 18 stops the operation of the exposure device 3 and causes the rotation of the photo-sensitive drum 1 by a number corresponding to the angle EC. Thereafter, the control section 18 stops operation. |
