| 摘要 |
PROBLEM TO BE SOLVED: To save the energy of a fixing means and to shorten a warming-up time by transferring a toner image on an image forming body to the front surface of transfer material or transferring it to the rear surface of the transfer material after temporarily transferring it to an intermediate transfer body. SOLUTION: In an interval between the passing of first recording paper P and that of second recording paper P, a heat storage elastic roller 17b is heated by making a thermal fixing film 17a in an on-state and setting it at higher temperature than the set value of front surface image fixing temperature. When the roller 17b is heated, the heating of the film 17a is turned off. Next, at the time of forming a one-side image on the front surf ace in a 2nd image forming mode, the carrying timing of the recording paper P passing through a fixing device 17 is continuously kept. The temperature control of the film 17a such as turning on/off the film 17a at the higher temperature than the set value of the appropriate front surface image fixing temperature in the midst of forming the image is performed by making a ceramic heater 172 successively take timing with the passing timing of the recording paper P, and then the front surface image is fixed. |
