9
Check the drum current in the front frame side and the rear frame
side. Difference between the front frame side current and the rear
frame side current must be within 7.0 uA.
a. Turn on the main switch and execute simulation 8-02. (MTHV
is turned on for about 30 sec.)
b. Measure the drum current in the front frame side and in the
rear frame side.
•
When the microswitch is OFF: The drum current in the front
frame side is displayed.
•
When the microswitch is ON: The drum current in the rear
frame side is displayed.
c. Check that the difference between the front frame current and
the rear frame current is within 7.0
µ
A. If the difference ex-
ceeds 7.0
µ
A, the charger unit is abnormal. Replace the char-
ger unit in that case.
2) Charging grid voltage adjustment
Before this adjustment, check that the photoconductor drum, and
developing unit, and the charger (MC/TC) units are attached.
(Measurement and adjustment at the high voltage PWB check point)
1
Remove the rear cabinet.
2
Set the digital multi meter range to DCV, and connect to the grid
voltage output check pin (GB).
3
Turn on the copier power and execute simulation 44-11.
4
Select the standard mode (A) with the magnification ratio display
key on the operation panel. (The mode is displayed on the copy
quantity display.)
Execution of simulation 44-11
Select the standard mode (A) with the magnification ratio select key.
(Reference)
Display
Mode
A
Standard
–750
±
5V
b
Photo
–500
±
5V
C
TS
–650
±
5V
d
GB patch
–410V
→
GB is not adjustable.
5
Use the 10-key pad to adjust so that the measurement value by
the tester in the standard mode (A) is –750
±
5V. (Input value 1
corresponds to 5V.)
*
For the voltage check, enter the value with the 10-key pad and
press the PRINT button to store it, and press the PRINT button
again and measure the voltage with the tester while copying.
6
Adjust similarly in the photo mode (b), and in the toner save mode
(C).
Check the GP patch (d) after adjustment of standard (A), photo (b)
and TS (c).
•
Grid voltage adjustment
(Sim 44-11)
Display
Mode
Grid
Input value
(Standard)
* 1
2
(Input value 1
corresponds
to 5V.)
d (GB) is fixed.
A
Standard
–750
±
5V
48
b
Photo
–500
±
5V
46
C
TS
–650
±
5V
46
d
GB patch
–410V
41
•
Grid voltage check
Grid voltage
Sim No.
Mode
*
Drum marking number: 1
*
Drum marking number: 2
8-2
Standard
–740
–770
8-3
Photo
–480
–480
8-4
TS
–630
–650
*
Drum marking number 1 = SHARP
Drum marking number 2 = Mitsubishi
*
This model performs the process correction according to the num-
ber of drum mark(s). With Sim 8, the grid voltage after correction
can be checked.
3) Developing bias (BS) voltage adjustment
The developing bias voltage is measured and adjusted with the check
pin (DV BIAS) on the high voltage PWB and the control knob
(VR301).
In advance to this adjustment, check that the photoconductor drum,
the developing unit, and the charger (MC/TC) units are installed.
1
Remove the rear cover.
2
Set the digital multi meter range to DCV, and connect it to the
developing bias output check pin (DV BIAS).
3
Turn on the copier power, and execute simulation 8-01.
4
During execution of the simulation, check that the developing bias
output monitor voltage is –200
±
5V. If the voltage is outside the
range, adjust with the control knob (VR301).
N/C
N/O COM
(OFF)
N/C
N/O COM
(ON)
GB
7 – 23
