Ricoh Aficio FX10, Service Manual

Page: 66 / 284

Fusing Control
During normal operation, the cpu controls the fusing lamp based on input
from the thermistor using the above circuit.
When the machine switches on, or when it comes back from the Level 2
Power Saver Mode, it checks whether the thermistor circuit is intact by tempo-
rarily closing the initial detect switch circuit on the FCU. If the thermistor is
connected properly, the machine begins normal operation. If it is not, an Auto
Service Call (error code 9-22, sub-code 09) is generated.
As a backup safety measure, when the temperature of the hot roller reaches
about 400 °C, the thermostat and/or the thermofuse open (the thermofuse is
not installed in USA models).
The machine turns on the cooling fan when the fusing temperature reaches
120 °C. It is turned off when the fusing temperature drops below 120 °C.
FCU
FCIP2
25-1
25-2
12-1 12-2
Comparator
+5V +5V
THR SEL
Thermistor Temp
Thermistor Max
Thermistor
PSU
Thermofuse Thermostat
Fusing Lamp
*
H523D662.wmf
* The thermofuse is not
used in USA models.
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June 10th, 1997 DETAILED SECTION DESCRIPTIONS
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