Oki OF5600, Service Manual

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Board Descriptions A - 39 OF 5300/5600 Serv Man, P/N 59278301
3) High-voltage and medium-voltage control
High voltages are activated by IOGA3 and generated by the high-voltage circuit
inside the power supply unit. The CH (charge) voltage of about -1.35 kV is used
for the charge roller. The TR1/TR2 (transfer) voltage of about +3.5 kV/-0.75 kV is
used for the transfer roller.
Medium voltages are activated by IOGA3 and generated by the medium-voltage
circuit inside the power supply unit. The SB1/SB2 (toner supply) voltage of about
+0 V/-450 V is used for the toner supply roller. The DB1/DB2 (developping)
voltage of about +300 V/-300 V is used for the developing roller. The CB (clean-
ing) voltage of about +400V is used for the cleaning roller.
Figure A3.2.19 shows high/medium voltages control.
* Signals used to control the high/medium-voltages are listed below.
Signal Name
CHPWM P.W.M : CH is output.
Description
DB1ENB "1": + ive polarity voltage of DB1/SB1 is output.
DB2ENB "1": - ive polarity voltage of DB2/SB2/CB is output.
TR1PWM P.W.M : TR1 is output.
TR2PWM P.W.M : TR2 is output.
DBPWM P.W.M : DB/SB/CB is output.
IOGA3
DBON1
DBON2
DBPWM
TR1PWM
CHPWM
TR2PWM
M17 1VP/2VP (Power supply unit)
High-voltage
generation
circuit
Medium-
voltage
generation
circuit
Contact assy.
Cleaning roller
Charge roller
EP drum
Transfer roller
Developing roller
Toner supply roller
CH
TR1/TR2
CB
DB1/DB2
SB1/SB2
High/Medium Voltage Control (Figure A3.2.19)