The function of the Fuser gear product in the printer is to melt the toner by heating, forming a liquid that penetrates into the paper fibers, and forms permanent characters or images on the paper after cooling. Although existing laser printers use two different heaters: fixed lamps and ceramic heaters, the fixing principles are the same. The manufacturer of Fuser gear tells you that the CPU on the motherboard controls the conduction angle of the triac based on the temperature data detected by the thermistor, and controls the operation of the heater by switching the thyristor.

In the printer Fuser gear products, the thermistor is used to detect the surface temperature of the fixing roller, and generally has a negative temperature coefficient, high temperature, low resistance, low temperature, and high resistance. In the detection circuit, the thermistor is connected in series with a fixed resistor and connected to a +5v power supply. According to the principle of resistance voltage division, the voltage across the thermistor reflects the fixing temperature. By sending this voltage to the a/d converter, the central processing unit can obtain fixed temperature data. The manufacturer of Fuser gear tells you that the temperature limiter is actually a kind of protector. The power supply circuit of the heater will be disconnected only when the normal control function of the circuit fails and the fixing temperature rises abnormally. In the circuit, the temperature limiter is connected in series with the heater's power supply circuit, and its on-off directly affects the operation of the heater. The internal structure of the temperature limiter is a bimetal with electrical contacts at both ends. If the detected temperature is lower than the operating temperature, the electrical contact is closed; if the temperature is higher than the operating temperature, the bimetal will deform to open the electrical contact.
Mechanically, the pressure between the pressure roller and the fixing roller is adjustable. If the pressure is too high, the operation resistance of the whole device is large, the wear is accelerated, and the service life is shortened. The most obvious example is that the Fuser gear product produced some unusual noises during the printing process, as if the entire device was not sufficiently lubricated. If the pressure is too low, the toner will only penetrate into the surface of the paper fiber after melting, which will easily lead to unstable fixing. In the fixing process, the toner has a certain viscosity after melting, and the paper is easy to adhere to the surface of the fixing roller. Generally, the paper is forcibly separated from the fixing roller by using separation claws. The role of the fan is to cool the internal temperature of the machine. The manufacturer of Fuser gear tells you that the temperature is high during printing and the fan speed is high. After printing, the fan speed decreases. After a period of time, when the internal temperature drops to a normal temperature, the fan enters a sleep state and no longer runs.