Sharp DM-1500, Service Manual

Page: 65 / 188

[8] ADJUSTMENTS
1. Optical section
A. Image distortion adjustment
There are following two types of image distortion.
●
Horizontal image distortion
●
Vertical image distortion
In this machine, the image distortion is adjusted by changing the paral-
lelism of mirrors (copy lamp unit, No. 2/3 mirror unit).
(1) Horizontal image distortion adjustment
a. Summary
Parallelism of mirrors can be made by installing the copy lamp unit
and No. 2/3 mirror unit to the reference position. However, it must
be checked by making a copy, and must be adjusted if necessary.
b. Cases when the adjustment is required
1) When the copy lamp unit and No.2/3 mirror unit are disas-
sembled or their part is replaced.
2) When the copy lamp unit and No.2/3 mirror unit drive section is
disassembled or its part is replaced.
3) When the copy image is distorted as shown below:
c. Necessary tools
●
Screwdriver (+)
●
Hex wrench
●
Scale
●
Test chart for distortion adjustment (Make a chart shown below
by yourself.)
Draw a rectangle on a paper (B4 or 8 1/2
″ ×
14
″
) as shown
below.
Be sure to make four right angles.
d. Adjustment procedure
1) Remove the right cabinet (manual paper feed unit), the docu-
ment reference plate.
2) Remove the document glass.
3) Loosen the fixing screw of the copy lamp unit wire.
4) Manually turn the copy lamp unit/No.2/3 mirror unit drive gear to
bring No.2/3 mirror unit into contact with No.2/3 mirror unit
positioning plate. When No.2/3 mirror unit makes contact with
No.2/3 mirror unit positioning plate in the rear frame side simul-
taneously, the mechanical parallelism of No.2/3 mirror unit is
proper.
If one side of No.2/3 mirror unit makes contact with No.2/3 mir-
ror unit positioning plate and the other side does not, the paral-
lelism is improper.
If the parallelism is improper, perform the procedure of step 5).
Document
Copy A
Copy B
L
L
L L
L = 10mm
1)
2)
3)
Fixing Screws
DM-1505
8 – 1