| 摘要 |
PURPOSE:To control the surface temperature of a fixing roller always at a fixed value by increasing a set temperature in accordance with a difference between a detecting temperature corresponding to heat generated between a fixing roller and a temperature detecting element and the set temperature by the rotation of the fixing roller. CONSTITUTION:At the stop of the fixing roller 2, a change-over switch S is turned to the (a) side, the set temperature T1 is set up to 180 deg.C and the surface temperature of the fixing roller 2 is controlled at 180 deg.C set temperature by a fixing temperature control means 12. When copying operation is started by depressing a copy button 18 and the fixing roller 2 starts to rotate, the switch S is turned to the (b) side and the set temperature T2 is set up to 190 deg.C. Although a thermistor 11 detects the surface temperature of the roller 2 10 deg. higher than the real temperature because of friction or convective heat at the rotation of the fixing roller 2, the surface of the roller 2 is controlled at 180 deg.C equal to the temperature set up at the stop of the roller 2 by the control means 12 because the set temperature T2 of the roller 2 is 190 deg.C.
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