Fig. 3-19 Heater Control Circuit &Associated Components - Canon NP-70 Service Manual

3-54
NP-70
3.4-9 HEATER CONTROL CIRCUIT (100VAC COPIERS ONLY)
The heater control circuit operates to maintain the temperature of the Heater Assembly at
180 ± 3°C through the controlling of the operation of heaters H2 & H3. The limiting of the
Heater Assembly to the above temperature range assures the proper fixing action as the copy
exits the machine.
Fig. 3-19 shows the heater control circuit and its associated components.
100VAC p
+24VDC ~
OVDC O
100VAC O
TH1
r
COMP.
NETWORK
AMP
C28
Q41
TP
MS6B
H3
T
H2
Q42
H1
~ HEATER CONTROL CIRCUIT CARD ~
L
------------ ----- J
Fig. 3-19 Heater Control Circuit &Associated Components
The operation of the heater control circuit is explained in the flowchart in Fig. 3-20 and the
accompanying table (3-6).
Second Printing-June, 1974
© CANON INC.