The main function of Fuser thermistor is to adjust the fixing temperature. The Fuser thermistor is tightly attached to the upper fixing roller or ceramic heater. When its temperature changes, its resistance changes. The logic circuit controls the switch of the heating lamp to realize the adjustment and constant temperature of the fixing temperature. The Fuser thermistor used in laser printers basically has a negative temperature coefficient.

That is, the higher the external temperature, the lower the resistance of the Fuser thermistor. When the lamp tube starts to heat up. The temperature of the heating roller gradually increases, and the resistance value of the Fuser thermistor decreases. When the surface temperature of the heater reaches the rated temperature, the resistance value of the Fuser thermistor is also lower, and then the heater is controlled to stop heating through the logic control circuit. This is repeated to control the surface temperature of the heater to keep within the designed temperature range.
The application of the fuser thermistor is multi-layered, that is to say, it exists in many parts. The middle Fuser thermistor is mainly used to detect the temperature of the fuser roller and control the on and off of the fuser lamp; the Fuser thermistor on the side is the auxiliary Fuser thermistor. If the paper does not absorb heat because the paper does not pass through the heat roller, the two fuser rollers will not absorb heat. The side may overheat. The sub-temperature Fuser thermistor can detect abnormal heat generation in this area due to overheating of the fixing roller. Therefore, the sub-Fuser thermistor is not used for temperature control of the fixing roller, only monitoring the temperature of the fixing roller is abnormal.
The role of the fuser thermistor cannot be underestimated. Without the existence of this electronic component, the performance of the fuser cannot be guaranteed. And relatively speaking, the quality of electronic components determines the effect and service life of the fuser. Therefore, focusing on quality selection is an important detail.