
Chapter 8
8-9
F-8-10
T-8-4
8.3.4 Determining the Optimum Grid Bias
0006-9596
iR105i/iR105+ / iR9070 / iR85+ / iR8070
A grid bias is selected so that the surface potential of the drum will be identical to the target potential (the primary charging bias is fixed).
F-8-11
8.3.5 Grid Bias Corrective Control
0006-9598
iR105i/iR105+ / iR9070 / iR85+ / iR8070
Related Service Mode
COPIER> OPTION> BODY> PO-CNT
(potential control on/off)
0: disable potential control.
1: enable potential control. (default)
COPIER> ADJUST> V-CONT> EPOTOFST
(potential sensor offset value input)
If you have replaced the image processor
PCB or initialized the RAM on the image
processor PCB, enter the value recorded on
the service label.
COPIER> ADJUST> V-CONT> VL-OFST
(VL target potential offset input)
COPIER> ADJUST> V-CONT> VD-OFST
(VD target potential offset value input)
COPIER> FUNCTION> DPC> OFST
(potential sensor offset adjustment)
For adjustments, see descriptions on
electrical parts.
[1] The control panel power switch is turned on.
[2] The front door is opened/closed.
10 min
60 min
The charging characteristics are likely to have
stabilized at this point, and potential control will
not be executed after this point.
Potential control is executed 10 min and 60
min after the temperature of the fixing
assembly has reached 195˚C.
Main power
switch ON
Potential
control for
transparency
Print com-
mand
Potential
control
Potential
control
Potential
control
Fixing assembly temperature at 195˚C
(end of fixing assembly warm-up)
Print com-
mand
WMUPR
WMUP
STBY
195˚C
200˚C
Potential sensor
Grid bias
500 V
600 V
700 V
Measurement
(VD1)
Measurement
(VD2)
Measurement
(VD3)
Vg
500V 600V 700V
VD1
VD2
VD3
Grid bias
If the target VD is attained basde on this
measurement, control is ended; otherwise,
corrective control will start.
The relationship between the surface potential of
the drum (VD) and the gird bias is obtained based
on measurements taken several times.
Charging
characteristic curve
A grid bias (VG) needed to attain the
target VD is selected.
Potential control
sequence started
Primary charging
bias (DC)
Measurement
(targetVD)
Summary of Contents for ImageRunner iR8500 Series
Page 1: ...Apr 5 2005 Service Manual iR8500 Series ...
Page 2: ......
Page 6: ......
Page 32: ...Contents ...
Page 33: ...Chapter 1 Introduction ...
Page 34: ......
Page 98: ......
Page 99: ...Chapter 2 Installation ...
Page 100: ......
Page 180: ...Chapter 2 2 78 F 2 272 2 1 1 3 ...
Page 181: ...Chapter 3 Basic Operation ...
Page 182: ......
Page 184: ......
Page 207: ...Chapter 4 Main Controller ...
Page 208: ......
Page 245: ...Chapter 4 4 35 F 4 72 1 2 ...
Page 246: ......
Page 247: ...Chapter 5 Original Exposure System ...
Page 248: ......
Page 252: ......
Page 306: ......
Page 307: ...Chapter 6 Image Processing System ...
Page 308: ......
Page 310: ......
Page 319: ...Chapter 7 Laser Exposure ...
Page 320: ......
Page 322: ......
Page 335: ...Chapter 8 Image Formation ...
Page 336: ......
Page 340: ......
Page 399: ...Chapter 9 Pickup Feeding System ...
Page 400: ......
Page 404: ......
Page 482: ......
Page 483: ...Chapter 10 Fixing System ...
Page 484: ......
Page 524: ......
Page 525: ...Chapter 11 External and Controls ...
Page 526: ......
Page 530: ......
Page 583: ...Chapter 12 MEAP ...
Page 584: ......
Page 586: ......
Page 589: ...Chapter 13 Maintenance and Inspection ...
Page 590: ......
Page 592: ......
Page 610: ...Chapter 13 13 18 F 13 17 1 2 3 ...
Page 648: ......
Page 649: ...Chapter 14 Standards and Adjustments ...
Page 650: ......
Page 654: ......
Page 723: ...Chapter 15 Correcting Faulty Images ...
Page 724: ......
Page 728: ......
Page 792: ......
Page 793: ...Chapter 16 Self Diagnosis ...
Page 794: ......
Page 796: ......
Page 841: ...Chapter 17 Service Mode ...
Page 842: ......
Page 1076: ......
Page 1077: ...Chapter 18 Upgrading ...
Page 1078: ......
Page 1080: ......
Page 1108: ...Chapter 18 18 28 F 18 45 3 Click Start F 18 46 4 Click Save F 18 47 5 Click OK ...
Page 1111: ...Chapter 19 Service Tools ...
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Page 1121: ...Apr 5 2005 ...
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