Pc Drum Cleaning Section; Pre-Cleaning Charge Corona - Minolta CF910 Service Manual

1154SBM1700A
17

PC DRUM CLEANING SECTION

1154SBM1701A

17-1. Pre-Cleaning Charge Corona

• The Pre-Cleaning Charge Corona employs a corotron system to deposit either an AC or
DC negative corona emission, selected as necessary, to the surface of the PC Drum to
neutralize any residual charge on it.
• The Pre-Cleaning Charge Corona output is controlled by High Voltage Unit 1 HV1.
AC corona emission Neutralizes residual charge on toner and PC Drum
DC negative corona
emission
<Control>
Control Signal
AC PWB-I PJ11I-6
HV1
-DC PWB-I PJ11I-5
Transfer Drum Reference
Position Sensor 1 PC20
PC Drum Drive
Motor M18
HV1 (DC)
HV1 (AC)
Image Transfer Corona
• If an electric discharge occurs when the trailing edge of the paper
leaves the PC Drum after image transfer, a positive latent image
is produced on the surface of the PC Drum.
• A DC negative corona emission is applied to a band on the sur-
face of the PC Drum opposing a band of ±18 mm on the trailing
edge of the paper.
Paper
Pre-Cleaning Charge Corona
A'
A
PC Drum
1144M099AA
Energized
Start key ON
H
L
ON
OFF
ON
OFF
ON
OFF
ON
OFF
(HV3)
M-114
Use
The corona emission is switched from
AC to DC negative when band A comes
immediately under the Pre-Cleaning
Charge Corona (that is A'); otherwise,
an AC corona emission is applied.
Deenergized
L H
L H
Approx. 2.3 sec. Approx. 0.2 sec. Approx. 0.3 sec.
Wiring Diagram
15-I
1154T37MCA