Xerox Phaser 6280 Service Manual page 91

Theory of Operation
Heater Lamp
The Heater Rods are glass tubes containing heater coils. The Main
Heater Lamp heats the entire length of the Heat Roller, and the Dual Sub-
Heater Rods heat the center.
Thermostat
The Thermostat provides a second-level of protection. If the Heat Roller
temperature exceeds the current temperature, the Thermostat cuts off the
AC power to the Heater Lamps.
Temperature Sensors
The temperature sensors are thermistors having a known value of
resistance that varies with temperature. There are two Temperature
Sensors. The Soft Touch Sensor (STS) is located at the edge of the
Heater Lamp, and the Non-Contact Sensor (NCS) is located at the center
of the Fuser. The sensors monitor temperature of each location to control
lighting of the Heater Lamp. The Sensors are mounted in contact with the
surface of the Heat Roller. Power to the Heater Lamp is turned On and Off
using the signals from these sensors, so that the surface temperature of
the Heat Roller can be maintained within a specified range. This signal is
also used to provide a first stage of overheat protection.
Pressure Belt
The Pressure Belt maintains pressure on the paper passing between it
and the Heat Roller. The pressure bonds the melted toner to the paper.
Exit Roller
The Exit Roller transports paper from the Fuser to the output tray.
Exit Sensor
The Exit Sensor detects passage of printed pages after fusing on the
Actuator's position changes.
Phaser 6280 Color Laser Printer Service Manual 2-29