The main function of Fuser thermistor is to adjust the fixing temperature. Fuser thermistor is closely attached to the fuser upper roller or ceramic heater. When its temperature changes, its resistance value changes, and the logic circuit controls the switch of the heating lamp, so as to realize the adjustment and constant temperature of the fuser temperature. The Fuser thermistor used by 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 tube starts to heat up. The temperature of the heating roller increases gradually, 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 logic control circuit controls the heater to stop heating. This is repeated to control the surface temperature of the heater to keep within the designed temperature range.
The application of Fuser thermistor is multi-level, that is to say, it exists in many parts. The middle Fuser thermistor is the main one, which detects the temperature of the fixing roller and controls the on-off of the fixing lamp; the Fuser thermistor on the side is the secondary Fuser thermistor, because the paper does not pass through the heat roller and the paper does not absorb heat, the two sides of the fixing roller side may overheat. The sub-temperature Fuser thermistor detects abnormal heat generation in this area due to overheating of the fixing roller. Therefore, the auxiliary Fuser thermistor is not used for the temperature control of the fixing roller, but only monitors the abnormal temperature of the fixing roller.
The role of 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, paying attention to quality selection is an important detail.