Sharp DM-1500, Service Manual

Page: 67 / 188

10) Check the horizontal image distortion.
If LL = LR, there is no horizontal distortion
11) If LL is not equal to LR, perform the following procedure.
Loosen the setscrew of the copy lamp unit/No.2/3 mirror unit
drive pulley in the front or the rear frame.
12) Without moving the copy lamp unit/No.2/3 mirror unit drive pul-
ley shaft, manually turn the copy lamp unit/No.2/3 mirror unit
drive pulley whose setscrew was loosened, and adjust the
parallelism of copy lamp unit/No.2/3 mirror unit.
13) Tighten the set screw of the copy lamp unit/No.2/3 mirror unit
drive pulley.
14) Check the image distortion in the same manner as step 10).
Repeat procedures 11) to 14) until horizontal image distortion
is eliminated.
(2) Vertical image distortion adjustment
a. Summary
In this adjustment, the left and right balance is adjusted by changing
the left and right balance of the No. 2 scanner unit frame on the
front frame side.
b. Note
●
Horizontal image distortion adjustment
c. Cases when the adjustment is required
1) When the copy lamp unit/No.2/3 mirror unit drive section is dis-
assembled or its part is replaced.
2) When the copy image is distorted as follows:
d. Necessary tools
●
Screwdriver (+)
●
Screwdriver (–)
●
Scale
●
Test chart for distortion adjustment (Make by yourself.)
Draw a rectangle on A4 or 8 1/2
″ ×
11
″
paper as shown below:
Be sure to make four right angles.
e. Adjustment procedure
1) Set the test chart for image distortion adjustment on the docu-
ment glass, and make a normal copy on a paper of A4 or 8 1/2
″
×
11
″
.
2) Check image distortion in the right and the left sides.
If the both vertical lines are in parallel with each other, the right-
left distortion balance is proper. (However, there may be some
distortion.)
2) If all the four angles are right angles, there in no distortion and
the following procedures are not required.
LL LR
LL and LR: Distance between the copy
image horizontal line and
the edge of the black
background.
Black background
Set screw
Scanner unit drive pulley
Document
Copy C
Copy D
L
L
L L
L = 10mm
Greater distortion
Smaller distortion
DM-1505
8 – 3