User Guide

166 Chapter 5 - Theory of operation EN
Fuser control
The fuser controller directly interfaces with both the power supply and
controller board. As the surface temperature of the upper and lower
fusing rollers rises, the resistance of the thermistors drops and the
voltage of the fusing temperature detection signals also drops.
Table 31 shows the temperatures the formatter sets, based on the
media in use.
Problems in the fuser can be detected in the following three circuits:
Controller board. If the fuser is heated abnormally or does not
reach the specified temperature for some reason, the controller
board interrupts power to the fuser heaters. From there, the
formatter assesses the fusing heater failure and signals the
printer control panel.
Fusing heater safety circuit (in the power supply circuit). If the
fusing heater safety circuit detects an upper or lower fusing
heater failure, the safety circuit interrupts power to the upper and
lower fusing heaters.
Fuser abnormality detection circuit (in the power supply circuit). If
there are broken wires to the fusing heater system, the fuser
abnormality detection circuit detects no AC current flow, causing
the controller board to assess the broken wires, stop driving the
fusing heaters, and signal the printer control panel.
Table 31. Fusing temperatures
Color
mode
Number of
sheets
Fusing mode
Plain
paper OHT
Heavy or
glossy Envelope
Target
temperature
Full color
1st sheet
175° C
347° F
175° C
347° F
175° C
347° F
180° C
356° F
2nd and after
165° C
329° F
170° C
338° F
165° C
329° F
180° C
356° F
Black and
white
1st sheet
180° C
356° F
175° C
347° F
175° C
347° F
180° C
356° F
2nd and after
165° C
329° F
170° C
338° F
165° C
329° F
170° C
338° F