| 摘要 |
PROBLEM TO BE SOLVED: To execute excellent fixing by stably controlling temperature by mitigating the temperature change of a fixing body during fixing in on/off duty ratio control regardless of the existence of a condition affecting temperature control. SOLUTION: Upper limit temperature Ts+βand lower limit temperature Ts-αare set above and under set temperature Ts, and temperature control is executed based on an on/off duty ratio in the case that the detected temperature Th of the fixing body is set to be in areas B and C. In this case, the on/off duty ratio at each temperature area every time the detected temperature of the fixing body is set to be equal to or higher than the upper limit temperature (area D) is changed so as to reduce a ratio to turn on heating electric power, and the on/off duty ratio at the temperature areas B and C every time the detected temperature of the fixing body is set to be equal to or lower than the lower limit temperature (area A) is changed so as to increase the ratio to turn on the heating electric power, so that it is automatically adjusted so as to obtain an optimum on/off duty ratio.
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