Sharp AL-1043, Service Manual

Page: 73 / 126

AL-1551 ADJUSTMENTS 9-9
3) Make a copy.
Check the adjustment level (shown in the above table) of the
exposure test chart (Sharp Gray Scale).
(When too bright): Decrease the value displayed on the copy quantity
display.
(When too dark): Increase the value displayed on the copy quantity
display.
* The value can be set in the range of 1 - 99.
3. High voltage adjustment
A. Main charger (Grid bias)
Note:
•Use a digital multi meter with internal resistance of 10M
Ω
or more
measurement.
•After adjusting the grid LOW output, adjust the HIGH output. Do not
reverse the sequence.
Procedures
1) Set the digital multi meter range to DC700V.
2) Set the positive side of the test rod to the connector CN11-3 (GRID)
of high voltage section of the power PWB and set the negative side
to the frame ground (radiating plate).
3) Execute SIM 8-3. (The main charger output is supplied for 30 sec in
the grid voltage LOW output mode.)
4) Adjust the control volume (VR-141) so that the output voltage is -400
±20V.
5) Execute SIM 8-2. (The main charger output is supplied for 30 sec in
the grid voltage HIGH output mode.)
6) Adjust the control volume (VR-142) so that the output voltage is 580
±10V.
B. DV bias adjustment
Note: A digital multi meter with internal resistance of 1G
Ω
must be use for
correct adjustment.
Procedures
1) Set the digital multi meter range to DC500V.
2) Set the positive side of the test rod to the connector CN-10-1 (DV
BIAS) and set the negative side to the connector CN10-2 (FG).
3) Execute SIM 25-1. (The developing bias is outputted for 30 sec.)
4) Adjust the control volume (VR-121) so that the output voltage is -400
±5V.
4. Duplex adjustment
A. Adjusting the paper reverse position in memory for
duplex copying
This step adjusts the front surface printing (odd-number pages of a
document set) in the S-D mode copying and the leading edge position of
an image on even-number pages in the D-S mode.
That is, it covers the adjustment of the second surface printing mode
(image loss at the front edge of an image) in which image data is once
stored in memory.
The image data is read, starting from its front end in the document
delivery direction (Reference direction of document setting in the OC
mode)and stored in memory.
This stored image data is printed starting at the printing start position, in
the order of last-stored data to the first-stored data.
In other words, the front edge image loss of the image can be adjusted
by changing the document read end position.
(Adjustment procedure)
1) Preparing test chart (Draw a scale at the rear end of one side of a
sheet of A4 white paper or letter paper)
2) Set the test chart so that the scale is positioned as shown below, in
the S-D mode and the D-S mode.
Sharp Gray Scale adjustment level
Non toner
save mode
Toner save
mode
1 10 W 2 3 4 5 6 7 8 9
Slightly copied.
Not copied.
1 10 W 2 3 4 5 6 7 8 9
Slightly copied.
Not copied.
5 10
Scale (S-D mode) Scale (D-S mode)
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