Canon    LBP3310, Руководство по обслуживанию

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Chapter 2
2-12
2.4.2 High-Voltage Control
2.4.2.1 Outline
0018-3112
LBP3370 / LBP3310
The high-voltage power supply circuit generates the high-voltage required for the image formation.
It consists of the primary charging bias circuit, the developing bias circuit, and the transfer charging bias circuit.
The primary charging bias circuit generates the negative DC voltage and AC voltage. They are superimposed and applied to the primary charging roller. The circuit
also applies the negative DC voltage to the fixing film unit through the pressure roller. In addition, this circuit detects the presence of cartridge.
The developing bias circuit generates negative DC voltage and AC voltage. They are superimposed and applied to the developing cylinder.
The transfer charging bias circuit generates positive or negative DC voltage and applies the positive or negative DC voltage to the transfer charging roller.
These circuits are controlled by the commands from the CPU (IC201) on the engine controller.
The following section describes each generation circuit.
F-2-18
2.4.2.2 Primary charging bias generation
0018-3113
LBP3370 / LBP3310
The primary charging bias (PR) is generated according to two signals output from the CPU: the PRIMARY CHARGING DC BIAS DRIVE signal (PRDCC) and
the PRIMARY CHARGING AC BIAS DRIVE signal (PRACC).
The PRDCC signal is a clock signal to generate the DC bias and the primary charging DC bias is generated according to this signal. The PRACC signal is a clock
signal to generate the AC bias and the primary charging AC bias is generated according to this signal. The superimposed voltage of primary charging AC and the
primary charging DC biases is applied to the primary charging roller.
The primary DC bias changes with the developing DC bias in response to the image density information sent from the video controller.
2.4.2.3 Developing bias generation
0018-3114
LBP3370 / LBP3310
Developing cylinder
Photosensitive drum
Primary charging roller
Transfer charging roller
Pressure roller
Fixing film unit
PR
TR
DV
IC201
CPU
DVACC
TRNFOT
TRCRNT
TRPFOT
PRACC
PRDCC
IC301
Superimposed
Primary charging bias circuit
Engine controller PCB
CRGSNS
FB
IC301 IC301
AC voltage
generation circuit
DC voltage
generation circuit
Developing bias circuit
AC voltage
generation circuit
DC voltage
generation circuit
Transfer charging bias circuit
IC502
Negative voltage
generatiion circuit
Positive voltage
generatiion circuit
High-voltage power supply circuit
J300
JP305
J302
JP301
JP303
IC502
TRPWM
JP306
JP304
JP302
Superimposed