Sharp AR-162 Service Manual page 20

(3) Developing bias voltage adjustment
•
Note: Use a digital multi-meter with an internal resistance of
10MΩ or more.
1) Set the digital multi-meter range to DC700V.
2) Put the test rod of the digital multi-meter on the developing bias
voltage output check pin.
3) Turn on the power.
4) Adjust the adjustment volume VR31 so that the output voltage is
within the specified range shown below.
<Adjustment specification>
Mode
Developing bias voltage
(4) Grid bias voltage adjustment
•
Note: Use a digital multi-meter with an internal resistance of
10MΩ or more.
1) Set the digital multi-meter range to DC700V.
2) Put the test rod of the digital multi-meter on the grid bias voltage
output check pin.
3) Turn on the power.
4) Adjust the adjustment volumes (VR51, VR52) so that the output
voltage is within the specified range. (The voltage is outputted in
the grid bias high output mode during warming up, and in the grid
bias low output mode after completion of warming up.)
<Adjustment specification>
Mode
Grid bias LOW
Grid bias HIGH
Specification
DC-400±8V VR31
Specification
DC-400±20V VR52
DC-525±10V VR51
AR-162 ADJUSTMENTS – 2
B. Mechanism section
(1) Image lead edge position adjustment (SIM 50-1)
a. OC image lead edge position adjustment
Note: In advance to this adjustment, the sub scanning magnification
ratio adjustment must be performed.
1) Set a scale on the OC table as shown below.
2) Make a copy.
3) Check the copy output. If necessary, perform the following adjust-
ment procedures.
4) Execute SIM 50-1.
5) Set the OC lead edge position set value (Exposure display
<AUTO> ON) to "99."
The OC image scanning start position is shifted inside the docu-
ment edge.
6) Set the main cassette lead edge void adjustment value (Exposure
display <PHOTO> ON) * to "1."
The lead edge void becomes the minimum.
7) Set the print start position value (Exposure display <EXP1> ON)
to "99" and make a copy.
The print start position is shifted inside the document edge.
*The dimension varies depending on the model.
8) Measure the image loss R of the copied image. Enter the set
value of the image scanning lead edge position (Exposure display
<AUTO> ON) again.
•
1 step of the set value corresponds to about 0.127mm shift.
•
Calculate the set value from the formula below.
99 - R/0.127 (mm) = Image loss set value <R: Image loss meas-
urement value (mm)>
* The scanning edge is set.
(A line may be printed by scanning the document edge.)
Example: 99 - 4/0.127 = 99 - 31.5 = about 67
Note: If the set value is not obtained from the above formula,
perform the fine adjustment.
5mm
5
4mm
10
5mm
0mm
5
10