Canon Color imageRUNNER C4580 Service Manual - page 695
Chapter 19
19-50
7. V-CONT
Potential Control System Adjustment
T-19-34
8. PASCAL
Adjustment for auto gradation correction control
T-19-35
COPIER>ADJUST>V-CONT
Sub item
Description
level.
VCONT-Y/M/C/K - VCONT-Y/M/C/K (Used to adjust electric potential for image contrast.)
Adjustment range: -30 to 30 (10 V units) [Factory default/After RAM clear: 0]
The larger the setting value, the higher the density.
Whenever possible, avoid using this setting during normal operation.
2
VBACK-Y/M/C/
K
- VBACK-Y/M/C/K (Used to adjust electric potential for removing image fog.)
Adjustment range:
Y/M -6 to 12 (5 V units) [Factory default/After RAM clear: 0]
C/K -12 to 6 (5 V units) [Factory default/After RAM clear: 0]
The larger the setting value, the more fog is reduced.
Whenever possible, avoid using this setting during normal operation.
2
VD-LIM-Y
Adjusting the upper limit of charge DC.
Adjustment range: -10 to 0 (1 step: 25V) [Factory default/After RAM clear: 0]
Change a setting value when either of the following faulty images occurs.
- Color blanking in the highlight area (especially on low-density image)
- Fogging (when making a large number of low-density image copies)
2
VD-LIM-M
Adjusting the upper limit of chargeDC.
Adjustment range: -10 to 0 (1 step: 25V) [Factory default/After RAM clear: 0]
Change a setting value when either of the following faulty images occurs.
- Color blanking in the highlight area (especially on low-density image)
- Fogging (when making a large number of low-density image copies)
2
VD-LIM-C
Adjusting the upper limit of charge DC.
Adjustment range: -10 to 0 (1 step: 25V) [Factory default/After RAM clear: 0]
Change a setting value when either of the following faulty images occurs.
- Color blanking in the highlight area (especially on low-density image)
- Fogging (when making a large number of low-density image copies)
2
VD-LIM-K
Adjusting the upper limit of charge DC.
Adjustment range: -10 to 0 (1 step: 25V) [Factory default/After RAM clear: 0]
Change a setting value when either of the following faulty images occurs.
- Color blanking in the highlight area (especially on low-density image)
- Fogging (when making a large number of low-density image copies)
2
COPIER>ADJUST>PASCAL
Sub item
Description
level.
OFST-P-Y/M/
C/K
Use it to apply offset adjustment on the test print reading signal (Y) for PASCAL control at time
of auto gradation correction (full).
Method of Adjustment
- a higher setting will make the image darker after auto gradation correction (full).
Range of Adjustment: -128 to +128 [Factory default/After RAM clear: 0]
1