Sharp Kabushiki Kaisha Corporation

Tomoki Nakajima

Tamaki Mashiba

There are provided a fixing device and an image forming apparatus capable of reducing a sensing error of a surface temperature of a heating roller. The fixing device includes a temperature sensor for sensing the surface temperature of the heating roller, and a temperature calculation circuit. The temperature calculation circuit includes a noise removal prevention circuit. The temperature sensor includes an infrared ray sensing thermistor and a compensation thermistor, and the noise removal prevention circuit prevents removal of a part of an AC component (such as a high frequency component in a noise) included in a difference between outputs (difference output) of the infrared ray sensing thermistor and the compensation thermistor. Thus, the AC component is prevented from being offset when the difference outputs are averaged, thus reducing the sensing error of the surface temperature of the heating roller based on the average value of the difference outputs.

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Yamatokoriyama, Japan

Tomoki Nakajima