| 摘要 |
PROBLEM TO BE SOLVED: To prevent defective fixing by reducing the overshoot of the surface temperature of a roller for fixation even when a copy operation is temporarily suspended in a serial copy by the control of image adjustment or the like. SOLUTION: The surface temperatures of a fixing roller and a pressure roller are detected during the standby of a fixing device, and the on-off operation of each heater is repeated to control the surface temperatures in a fixed range (period Ea of Figure 4). A heater is turned on continuously, because the surface temperature continues to lower when a copy is started (Eb). After the surface temperature reaches 180 deg.C of a temperature control temperature (Ec), the on-off operation of the heater is repeated similarly. The overshoot is caused when control to suspend temporarily a serial copy operation is started in this state (Ed). In order to prevent the overshoot, the surface temperature is detected at the time of the restart of the copy operation (period Ee), and when the surface temperatures exceed 180 deg.C, the temperature control temperature is changed to be lowered by 10 deg.C, and thereby the lighting timing of the heater is delayed to suppress the total heat given to the roller.
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