Fuser Exit Sensor; Duplex Unit - Xerox 3450B - Phaser B/W Laser Printer Service Manual

Fuser Exit Sensor

The Exit Sensor monitors the paper movement. If the paper takes too long getting to
the sensor, or it stays on the sensor too long, the Main Board will shut down the
machine, the Control Panel LED will blink red, and a JAM 2 error message will
display on the Control Panel. The signal from the Exit Sensor is also used to control
paper feed to the Duplex Unit for duplex print jobs.

Duplex Unit

The Duplex Unit is mounted in the bottom of the printer. As paper leaves the fuser
and is picked up by the Exit Rollers, the drive direction is reversed to send the paper
down to the Duplex Unit. As the paper passes through the Duplex Unit, it activates the
Duplex Sensor. This in turn activates the feed roller to position the paper for printing
on the second side.
Theory of Operation 2-13