| 摘要 |
PURPOSE:To constitute an image forming device which can reduce thermal stress inside a device having the heat of a thermal fixing device. CONSTITUTION:The temp. of a fixing heater 23 is detected by a thermistor 26 of a temp. detecting means, as a voltage, and the detected voltage is converted into a pulse signal by an A/D converting circuit incorporated in an MPU 25. The pulse is inputted into the noninversion input terminal of an operation amplifier 32, and conducted by a transistor connected to the output terminal of the operation amplifier 32, and cooling fan 6 connected to the collector terminal of the transistor 33 is rotated/driven. Therefore, revolving speed is increased/decreased by the increase/decrease of the voltage. A rotational control means which can variably control the revolving speed of the cooling fan 6 is provided, so that the temp. inside the device can be kept at about a target temp. |
