Theory of Operation 2-15
Fuser Control
Fuser Temperature Control
During Fuser temperature control the printer’s target temperature is set based on the 
media type. The Heat Roller surface temperature is controlled to match the target 
temperature by turning the heater lamp On and Off.
The Heat Roller surface temperature is detected by two sensors. A Non-Contact 
Sensor (NCS) in the middle of the roller and the Temperature Sensor at the edge of 
the roller. These sensors are checked every 10 ms to maintain an even temperature 
across the Heat Roller. If the readings indicate the temperature is higher than the 
target, the heater lamp is turned Off. If the readings fall below the target temperature, 
the heater lamp is turned On.
For the target temperature, different temperatures are set for standby, printing, and 
process control. The target temperature is also changed according to the inside 
temperature detected with the Temperature/Humidity Sensor, print count, print mode, 
input power supply voltage and paper type.
Cool Down
During printing, the temperature distribution of the Heat Roller becomes uneven. To 
compensate, a wait time is provided and the heater lamp is kept Off. When Heat 
Roller temperature stabilizes, printing resumes.