Print Process - Sharp AM-900 Service Manual

8. Print process

8.1. Image forming process
Normal paper is used as print paper. A laser beam is used to expose
on the OPC surface to form latent electrostatic images, which are
developed into visible images (toner images) and are transferred on
paper. The basic operation is composed of the five processes: charg-
ing, exposure, development, transfer, and cleaning.
8.2. System diagram (1)
Paper
Pressure roller
Main
charger
brush
Separation
electrode
Transfer
Photoconductor
charge
drum (OPC)
Paper
roller
8.3. System diagram (2)
CONTROL PWB
57
TCON
16bit CPU
IC21
56
MCON
Logic
PWMSIN
circuit
Heat roller
Heater lamp
Laser Scanning Unit
Laser
beam
Developing roller
Supply roller
Toner
High Voltage PWB Unit
Constant
voltage Oscillation B1
control circuit Transformer
circuit
Feedback circuit
Short
protection
circuit
Constant
voltage Oscillation B51
control circuit Transformer
circuit
Feedback circuit
PWM
control
circuit
High Voltage Power Supply Unit
FU-EARTH
100MOHM
100V
4.7MOH M 4.7MOHM
DV
Development
Roller
Print
Voltage
SV
Supply
Roller
Cleaning
Voltage
print
TC
Transfer Charger
Roller Voltage
cleaning
MC
Main Charger
brush Voltage
Fig. 7
HV(+)
250MΩ
Rectifier
circuit
HV(-)
Rectifier
circuit
Constant
voltage(-)
circuit
Short
circuit
HV(-)
Rectifier
circuit
Constant
voltage(+)
circuit
Fig. 8
3 – 10
DC: -220V
DC: -280V
DC: +400V
DC: +3600V (D6 Cathode)
DC: -500V
DC: -950V
AC: -570V <--> -1330V
LASER MFP
Transfer Roller
TC
OPC DRUM
Separation electrode
Supply Roller
SV
Developing Roller
DV
Doctor
Charger Roller
MC
Heat Roller
FU-EARTH
Pressure Roller
AM-900U