Sharp FO-2970M Service Manual page 52

FO-2970MU
i. Electrical connection
Heater lamp: The 400W halogen lamp is used.
This spring presses the pressure roller with a 690g
pressure on one side.
Thermistor: Thermistor of chip type with good response is
used to respond to rapid heating (rapid warm-up
of about 8 sec) of the heat roller.
Temperature fuse 1 Temperature fuse 1 is installed to the fusing cover.
(132 C): It blows off when the ambient temperature of the
fusing cover rises abnormally (132 C).
Temperature fuse 2 Temperature fuse 2 is in close contact with the
(187 C): heat roller. It blows off when the heat roller tem-
perature rises abnormally high (187 C).
CNPRT
CONTROL PWB
ASIC
(LR38784A)
131 HLON
127 PWRLY
CPU
(SH7041)
RTH
118
• The heat roller surface temperature is maintained to the optimum level
by controlling ON/OFF of the heater lamp according to the tempera-
ture data (voltage) from the thermistor. The heat roller surface tem-
perature is controlled to 155 C. Two temperature fuses are provided
to protect the heat machine from an abnormally high temperature in
the fusing section. The heater lamp is lighted by the AC power.
CNPW
PRINTER PWB
2 15 HLON-
IC1
Driver
PWRLY-
1 16
+5V
CNRTH
1 +5V
2 RTH
+24VS +24V
CNFUSE
1 +24V
3 +24VS
POWER PWB
CNLN
1 ACL
2 ACN
Fig. 16
5 – 16
CNHT
1 HLL
Temperature
fuse (132 C)
Heater
lamp
CNHT
3 HLN
Thermistor
Temperature
fuse (187 C)