Dell 5110cn Color Laser Printer Service Manual - Page 572

Chapter 6 Principles of Operation 5.8 Fuser Control 5.8.1 Fuser temperature control As for the fuser temperature control, the target temperature is set, then the Heat Roll surface temperature is controlled so as to be the target temperature by turning on/off the Heater Lamp. Temperature of individual area of the Heat Roll is detected by the Fuser Non-Contact Sensor (NCS) in the middle of the Heat Roll and the Temp Sensor at the edge of it. NCS checks the temperature every 10ms. When the temperature detected higher than the target, the Heater Lamp will be turned OFF. When the result shows a lower figure, the Heater Lamp will be turned ON. The target temperature set up varies depending on the time of Warm-up, Printing, or Process Control. The target temperature will be changed based on the interior temperature detected by the Sensor Hum Temp, the difference of temperature between the center and edge areas of the Heat Roll, Printing Mode, or the Input Power Voltage. 5.8.2 Cool down As the printing continues, the distribution of temperature in the Heat Roll becomes uneven both in the paper feed and non-paper feed areas. Cooling Down is to provide a certain period of time without feeding paper so that the Heat Roll temperature can be distributed evenly. When the edge of Heat Roll temperature is high, cool down does the control to lower to target temperature. 5.8.3 Sensor Warm-up The Fuser NCS (Non Contact Sensor) at the center of the Heat Roll will be lose accuracy of detect temperature when the temperature of the Sensor itself is below -5°C. Therefore, the Sensor will be warmed up when the temperature is below -5°C. This action is called Sensor Warm-up. 6 - 53