C. High-voltage Power Supply Circuit
1. Outline
Figure 2-2-6
In response to the instructions from the CPU (IC402) on the engine controller, this circuit applies
the superimposed voltage of DC voltage and AC voltage to the primary charging roller and devel-
oping cylinder, a positive or negative DC voltage to the transfer charging roller, and a negative
DC voltage to the pressure roller.
This circuit changes the primary DC bias and developing DC bias according to the image den-
sity information sent from the video controller in order to adjust the image density.
2. Operation
a. Primary charging roller voltage generation
When a print instruction command is sent from the video controller, initial rotation starts and
the CPU outputs the PRIMARY AC DRIVE signals (PRACCK and PRACON). As a result, the pri-
mary AC bias is applied to the primary charging roller from the AC generation circuit in the pri-
mary high-voltage circuit. At the same time, the PRIMARY DC BIAS DRIVE signals (DCCK and
CHAPTER 2
2 - 12
CPU
IC402
Engine controller PCB
Super-
impose
Developing
cylinder
Photosensitive drum
Primary charging roller
Transfer
charging roller
J505
Voltage detection
circuit
Primary high-voltage circuit
DC generation
circuit
AC generation
circuit
AC current
detection circuit
DC generation
circuit
AC generation
circuit
Developing bias circuit
Comparator
circuit
Positive current
detection circuit
Positive voltage
generation circuit
Negative voltage
generation circuit
PRDCON
Comparator
circuit
Voltage
control circuit
DCCK
PRACCK
DCPWM
PRACON
CRGSNS
DVDCON
DVACCK
DVCHG
TRFAD
TRPCK
TRPWM
TRNCK
Primary
charging
Fixing
Development
Transfer
J501
J502
J503
Pressure roller
Fixing film unit
Transfer bias circuit
Voltage detection
circuit
Comparator
circuit
Super-
impose
Содержание LBP-1000
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Страница 108: ...VII MOTOR FAN A Locations Main motor Cooling fan Figure 3 7 1 CHAPTER 3 3 21 ...
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Страница 155: ...F Special Tools No special tools are required for this printer besides the standard tools CHAPTER 4 4 35 ...
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Страница 161: ...APPENDIX I GENERAL TIMING CHART A 1 II GENERAL CIRCUIT DIAGRAM A 3 III LIST OF SIGNALS A 5 IV MESSAGES TABLE A 11 ...
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