
11-21
CIRCUIT DESCRIPTION
Service Manual
11.4 High Pressure Printing
11.4.1 MHV (Electric Charge Printing Section)
Charging output of ENABLE is 'MHV-PWM LOW ACTIVE', which is charging output controlling signal. When MHV-PWM
signal is applied, regular voltage flows to OP-AMP non-inverting terminal via filter R401, C401, R402, and C402. It
becomes HIGH or LOW in comparison with feedback voltage which flows to OP-AMP inverting terminal. If OP-AMP output
becomes high, Q401 turns off, and voltage of 24V1 flows normally to base unit of Q404, switching TR, and it turns on.
After voltage flows to Q404, IC passes the first T401, and it increases as voltage, which is proportionate to time. When this
voltage reaches to the HFE critical point of Q404, it turns off. At this time, counter electromotive force is created on trans 1
by turn-off action, and energy is emitted to trans 2 to send voltage to output MHV voltage via high voltage output unit
consisted of rectifier circuit.
When OP-AMP output becomes low, Q401 and Q403 turn on. At this time, base voltage of Q404 becomes GND voltage
and Q404 turns off to prevent to create high voltage.
Charging circuit detects changes due to environment of charging roller, and applies proper voltage to OPC for each
environment. The environment changes (resistance) are detected by comparator, and comparator converts analog input
to digital output.
Depending on such digital output, program inputted in ROM of engine controller applies proper charging voltage for each
environment in consideration of resistance changes.
R409
5.6K
R408
10K
R410
100K
R416
BLR1/2W100MJ
ZD403
100V
D402
1N4148
C403
331
C404
472
R403
1.5M
R404
10K
C402
102
R401
47K
R402
22K
C401
473
D404
4KV
C405
104
R411
470
Q403
C945C-Y
R412
1/4W4.7J
Q404
C2316
ZD402
2.7VB
D403
D1NL20U
D401
1N4148
ZD401
2.7V
Q401
A708-Y
R415
RDS1/2W100K
T401
24V1
5V1
D455
1N4148
R460
RD1/8W1.5K
C456
MY2A473
13
12
IC103/F
7407
MHV_READ
50K
R458
RS1/8W30KF
C458
MY2A473
D456
1N4148
5V1
R400
5.6K
+
12
-
13
14
IC104/D
KA324
+
5
-
6
7
C406
CE-103
C407
103
C457
CE-103
R414
BLR1/2W60MF
R461
RD1/8W2.2KJ
C459
C-CE221
R450
MGR1/4W560KJ
5V1
C410
CE-104
C460
47uF
R413
30KF
MHV
20K
R417
100J
5V1
ZD404
3.3B
C409
3KV471
MHV
MHV_READ
>>
MHV-sen
>>MHV-sen
>> OPC
>> MHV
MHV PWM
CN1-#6
MHV READ
CN1-#10
4
2
1
5
6
7
Содержание Phaser 3450
Страница 12: ...3 4 Specifications Service Manual ...
Страница 28: ...4 16 Summary of Product Service Manual ...
Страница 75: ...6 20 Alignment Adjustments Service Manual ...
Страница 103: ...7 28 TROUBLESHOOTING Service Manual ...
Страница 129: ...9 2 BLOCKDIAGRAM Service Manual ...
Страница 131: ...10 2 CONNECTION DIAGRAM Service Manual ...