Specifications

2.1 Print Engine Control
2.1.4 Fusing Heater Control
Figure 2–5 shows how the fusing temperature varies after power and during
printing and standby operations.
Figure 2–7 shows the circuitry that controls the fusing temperature. The
surface temperature of the upper fusing unit roller is measured by thermistor
(TH1) and adjusted by the DC control board.
The fusing temperature sets the resistance of TH1, establishing the voltage
level for the analog signal. The resistance of TH1 decreases as the
fusing temperature increases. The following TH1 resistance readings are
measurable across pins 1 and 2 of the fusing unit connector (J743):
• Room temperature resistance of TH1 is approximately 239K .
• Operating temperature resistance of TH1 is less than 2.0K .
Figure 2–5 Fusing Temperature Chart
Technical Description 2–9