| 摘要 |
PROBLEM TO BE SOLVED: To continuously form an image in a state where an intermediate transfer body is cleaned by imparting charge having a reverse polarity to residual toner on the intermediate transfer body by an electrifying roller when a toner image is transferred to both surfaces or the back surface of the transfer material and applying bias voltage having the reverse polarity to the electrifying roller when the toner image is transferred only to the front surface of the transfer material so as to perform consecutive printing. SOLUTION: At the time of double-sided image forming and one-sided (back surface) image forming, the bias voltage obtained by superposing DC voltage on AC voltage and having the reverse polarity to developing toner is applied to the electrifying roller 141 so as to positively electrify the residual toner on the intermediate transfer body 14a. Then, the residual toner is restored to a photoreceptor drum 10 side by a primary transfer device 14c to which the DC current having positive polarity is applied at a transfer area 14b. In the midst of one-sided (front surface) image forming that the consecutive printing is performed, the bias voltage having the reverse polarity to the residual toner is applied to the roller 141 so as to stick the residual toner in a negatively electrified state to the peripheral surface of the roller 141. |
