VII.
Troubles caused by improper adjustment
(5) Focus adjustment (Resolution adjustment)
I.
Summary
The distance between the document and the photoconductor
drum is changed by changing No.4/5 mirror unit drive lever posi-
tion to adjust the focus.
II.
Purpose
The purpose of this adjustment is to correct the lens variations
and the optical section dimensional variations to have good copy
images with a proper focus.
III.
Note
Before performing this adjustment, the following adjustment
must have been completed. If not, this adjustment cannot be
performed properly.
*
Image distortion adjustment
IV.
Cases when the adjustment is required
1) When the lens or the mirror unit is disassembled or any one
of their parts is replaced.
2) When the scanner unit drive section is disassembled or its
part is replaced.
3) When a copy image of improper focus is obtained.
V.
Necessary tools
*
Screwdriver (+)
*
Test chart (One with the resolution adjustment chart)
VI.
Adjustment procedures
1) Set the test chart on the document table.
2) Make a normal copy (100%) on A4 or 8 1/2" x 11" paper.
3) Check that resolutions at the copy paper center and the four
angles are as shown in the table below:
(Standard)
(Unit: lines/mm)
Copy center
Corner
Normal (100%)
5.0
4.5
Enlargement 5.0
4.5
Reduction
4.5
3.6
If any resolution is out of the above specifications, perform
the following procedures.
4) Remove the right cabinet and the document reference plate.
5) Remove the document glass.
6) Remove the optical unit cover.
7) Loosen the fixing screw of No.4/5 mirror unit drive lever to
change the position of No.4/5 mirror unit drive lever or No.4/5
mirror unit.
In this case, do not shake No.4/5 mirror unit, just change its
position.
8) Make a copy and check that the resolutions are in the
specified range.
If any resolution is out of the specified range, repeat proce-
dures 1) to 8).
2.8
3.2
3.6
4.0
4.5
5.0
5.6
6.3
7.1
8.0
9.0
9.1
9.2
9.2
9.2
9.2
9.2
(Copy)
Check
the corners.
Document
reference plate
Document table glass
Right upper side cabinet
Optical unit cover
No.4/5 mirror rive lever fixing screw
No.4/5 mirror drive lever
No.4/5 mirror unit frame
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