| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus suppressing the occurrence of a temperature ripple when the temperature of a fixing device is controlled while controlling the increase in calculation amount. SOLUTION: A temperature sensor 366 detecting the temperature of a heat roller 362 heated by a heater 363, a triac 364 turning the power to the heater 363 on and off and CPU8 setting the on/off ratio of the triac 364 so that the temperature of the heat roller 362 is brought to a specified target temperature according to the detected temperature by a specified control timing for each control interval are provided. The predicted temperature of the heat roller 362 at the next controlled timing is calculated by the CPU8, using the average variation rate, which is obtained by dividing the difference between the present detected temperature and the detected temperature detected at the control timing immediately prior to it by the control interval. Furthermore, when the predicted temperature exceeds the target temperature, the on/off ratio is varied by the CPU8 so that the average variation rate is reduced. COPYRIGHT: (C)2004,JPO&NCIPI
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