4. Controlling the Pre-Transfer Corona Current
(DC component)
The DC current of the pre-transfer corona cur-
rent is switched by the pre-transfer charging level
control signal from the DC controller PCB.
The DC current of the pre-transfer corona cur-
rent is varied according to the voltage level (7 to
16 V) of the HVPCT signal.
Figure 3-321
5. Controlling the DC Component Overcurrent
of the Separation/Pre-Transfer Corona Current
If an overcurrent flows to the separation/pre-
transfer charging assembly, the HVTDC PCB
sends the high-voltage transformer stop signal
(HVOFF) to the HVTAC PCB, temporarily stop-
ping the corona current (DC/AC component)
applied to the pre-transfer/separation charging
assembly.
The copier operation continues in the pres-
ence of the HVOFF signal, and application of
corona current will be resumed when the level of
the application current returns to normal.
3. OPERATIONS AND TIMING
COPYRIGHT © 1996 CANON INC.
CANON NP6085 REV.0 JULY 1996 PRINTED IN JAPAN (IMPRIME AU JAPON)
3-66
-300
8
16
HVPCT signal voltage level
Pre-transfer corona current
(
µ
A)
(V)
OFF
7
ACON
Q158
Micro-
processor
(master)
Drive
circuit
Photosensitive drum
D/A
converter
Voltage
detection
circuit
J127
B9
AC transformer
AC transformer
DC transformer
Overcurrent
detection
circuit
Separation
charging
assembly
Pre-transfer
charging
assembly
HVTAC
HVTDC
CP101-5
CP101-4
J127
B7
J127
B8
HVSCT
HVPCT
DC current
detection circuit
Drive
circuit
Control circuit
Control circuit
Control circuit
HVOFF
DC current
detection circuit
Figure 3-322
Содержание NP6085
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