Fusing Control *
During normal operation, the cpu controls the fusing lamp based on input
from the thermistor using the above circuit.
When the machine is turned on, or when it comes back from the Level 2 En-
ergy Saver Mode, it checks whether the thermistor circuit is intact by
temporarily closing the initial detect switch circuit on the MFDU. If the thermis-
tor 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.
MFDU
Comparator
ADCH
ADCL
EXIO-1
(IC3)
1HTSAFE
Thermistor Output
Serial Interface
Bus Interface
MFCE
LPC
SCP
(CPU)
VPP4F
(A/D Converter)
CN1-23
CN1-24
CN1-22
CN1-27
CN1-26
PSU
Fusing Lamp
Control
Thermofuse
Thermostat
Fusing Lamp
Thermistor
EXIO-2
(IC4)
CN12-2
CN12-1
Initial Detection On/Off
H515D516.wmf
The Thermofuse is not installed in the 115V models.
DETAILED SECTION DESCRIPTIONS
December 21st, 1995
PRINTING
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