Xerox Phaser 4500 Service Manual

Theory of Operation 2-27
Temperature Stabilization
The Fuser automatically enters a stabilization process under two circumstances:
■ When the printer is processing thick paper.
After 50 sheets of continuous printing on thick paper (Thick Paper 1 mode), the
Fuser lamp turns off, the Main Motor stops, and the fans rotate at full speed until
the temperature of both Temperature Sensors drops to 190° C or below. Then the
printer continues printing the job. The process for Thick Paper 2 is the same,
except that it occurs after 30 sheets of continuous printing on thick paper.
■ When the side Fuser Temperature Sensor (STS) detects an abnormally high
temperature (over 245° C).
When the side Fuser Temperature Sensor detects an abnormally high temperature
(over 245° C), the printer stops the print job and enters the following cool-down
process, which continues until the target Control Temperature of 180° C - 185° C
(Standby) is reached:
■ Clear the paper path of all paper
■ Continue to run the Main Motor (Time-out 200 sec.)
■ Run the Fans at full speed
■ Control Fuser temperature with Short Lamp
Fuser Problems (U4 Error Code)
Major causes of a U4 error include the following:
1. Warm-up failure – Fuser warm-up not complete within 110 seconds after starting.
2. Cool-down error – Cool-down process not complete within 200 seconds.
3. Low Trouble temperature – The Fuser temperature drops to the Low Trouble
temperature (approximately current control temperature, minus approximately
25° C).
4. High Trouble temperature – The Fuser temperature rises to the High Trouble
temperature (approximately current control temperature, plus approximately
35° C).
5. STS circuit open
6. STS failure – The Heat Rod remains on for at least 10 seconds after warm-up has
completed.

Xerox Phaser 4500 Specifications

General

Brand	Xerox
Model	Phaser 4500
Category	Printer
Language	English