Panasonic UF-890 Service Manual page 246

High Voltage Drive Circuit (Charging, Development and Transfer)
High Voltage is provided through a DC to DC converter, which changes the +24 VDC supply voltage to -
650 VDC, and output approximately 0.72 KVAC (Steady current: 450 µA) for the Charging Block. The
Developer Circuit converts the +24 VDC to between -500 VDC for the development bias, and outputs
1,700 VAC(p-p) at a frequency of 1.7 kHz to charge the toner. The Transfer Circuit changes the +24 VDC
supply voltage to approximately +600 VDC (steady current: 3.0 µA/-800 VDC steady voltage).
PCR0
PCR1
IC 51
PDR1
CPU
PTR0
PTR1
3
2
Q509
3
1
2
Q510
3
1
2
Q511
1
2
GND
High Voltage Drive Circuit
CN52 CN39
2
3
4
5
3
Q512
6
3
1
2
Q513
1
HVPS
LPC PCB
246
Discharge Plate
Bias Transfer Roller
T
Bias Charge Roller
C
Toner
Cartridge
Development Roller
D
FG