Sharp AR-M450 Service Manual page 55

B. OC scan distortion adjustment
(MB-B rail height adjustment)
•This adjustment requires a high-level preciseness.
It is easier to perform the scanner unit distortion adjustment previously
described.
Before performing this adjustment, the following adjustment must have
been completed.
•LSU right angle adjustment
1) Make a test chart as shown below. (Print a self-print pattern 71.)
2) Make a copy from the table glass, and check it.
At that time, set the test chart correctly. If it is set in a distorted
position, the adjustment cannot be made correctly.
3) If the output value is not in the specified range, perform the following
adjustment.
4) Remove the front cabinet in front of the scanner, and check that
installing position of the MB rail.
5) Loosen the screw at the right of the MB rail to adjust.
<Specifications>
Measurement Specification
point
OC scan Angle in the
distortion above figure
adjustment
Set value
= 90°±0.13° 1 scale = about
0.25°shift in
AR-M350 ADJUSTMENTS 9-4
C. Vertical image distortion balance adjustment
(Copy lamp unit installing position adjustment)
1) Insert the front/rear mirror base drive wire into the frame groove and
press and fix it with the wire holder. At that time, do not tighten the
wire fixing screw. Change the direction of the lamp positioning plate.
(F and R)
2) Push the copy lamp unit onto the positioning plate, and tighten the
wire fixing screw.
<Note for assembling the copy lamp unit>
After fixing, manually shift the copy lamp unit a few times to check that it
moves smoothly.
D. Vertical image distortion balance adjustment
(No. 2/3 mirror base unit installing
position adjustment)
This adjustment is to adjust the parallelism of the mirror base to the OPC
drum surface and the original surface.
1) Manually turn the mirror base drive pulley to bring mirror base B into
contact with mirror base positioning plate.
If, at that time, the front frame side and the frame side of mirror base
B are brought into contact with the mirror base positioning plate
simultaneously, the parallelism is correct and there is no need for
adjustment.