5.5 Fuser Control
5.5.1 Fuser temperature control
As for the fuser temperature control, the target temperature is set, then the Heat Roll surface
temperature is controlled so that it can meet the target value 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. When the temperature detected is
higher than the target value, the Heater Lamp will be turned OFF. When the temperature is below the
target value, the Heater Lamp will be turned ON.
The target temperature setting varies depending on the time of Warm-up, Printing, or Process Control.
The target temperature varies according to such environmental factors as the interior temperature
detected by the Sensor Hum Temp.
5.5.2 Cooling down
As the printing continues, the temperature distribution in the Heat Roll becomes uneven both in the
paper feed and non-paper feed areas. Cooling Down suspends paper feeling for a certain period of
time so that the Heat Roll temperature distribution can be uniform.
When the temperature of the Heat Roll edge is high, cooling down is performed to lower the
temperature to the target value.
5.5.3 Sensor Warm-up
The Fuser NCS (Non Contact Sensor) at the center of the Heat Roll will be lose its accuracy of
detecting 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.
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Chapter 6 Principles of Operation