| 摘要 |
PROBLEM TO BE SOLVED: To detect the temperatures at a plurality of places by using a plurality of thermistors provided on a heating rotor without using an integrated circuit having a number of AD conversion ports (AD conversion circuits).SOLUTION: A fixing device includes: a heating rotor; heaters that heat the heating rotor; a sensor circuit part that includes a plurality of series circuits of a temperature thermistor and a capacitor of the heating rotor, where the capacitors have different capacitances from each other; a signal circuit part that receives an input of a sensor output voltage between the thermistors and capacitors, and switches the state of an output signal every time the sensor output voltage exceeding a threshold increases; and a processing circuit that includes a voltage output port to which the series circuits are connected in parallel and an input port to which the output signal is input, measures a rise time from the start of application of voltage to the series circuits to the rise of the output signal and a fall time to the fall of the output signal, and recognize the temperatures of detection objects of the thermistors on the basis of the measured times.SELECTED DRAWING: Figure 8 |
