Sharp MX-4100N Service Manual page 70

2) Set the test chart prepared in the procedure 1) on the docu-
ment table. (Shift the test chart edge 30mm from the reference
position as shown below.) With the document cover open,
make a copy on A3 (11" x 17") paper.
3) Check for distortion in the sub scanning direction.
If La = Lb, there is no distortion.
La
If there is any distortion in the sub scanning direction, perform
the following procedures.
4) Loosen either one of the fixing screws of the scanner unit drive
pulley. (Either one on the front frame or on the rear frame will
do.)
5) Without moving the scanner unit drive shaft, manually turn the
scanner unit drive pulley to change the parallelism of the scan-
ner unit A and B. (Change the relative position of the scanner
unit drive pulley and the drive shaft.)
6) Tighten the scanner unit drive pulley fixing screw.
Repeat the procedures 2) - 6) until the condition of the procedure 3)
is satisfied.
If the distortion in the sub scanning direction cannot be deleted with
the above procedures, perform "ADJ 11D Scan image distortion
adjustment (whole scanner unit).
11-C
1) Make a test chart on A3 (11" x 17") paper as shown below.
(Draw a rectangular with four right angles.)
L
2) Set the test chart prepared in the procedure 1) on the docu-
ment table, and make a copy on A3 (11"x 17") paper.
3) Check for distortion in the main scanning direction.
If the four angles of the rectangle on the copy are right angles,
Lb
there is no distortion and therefore no further steps are
needed.
If there is any distortion in the main scanning direction, perform
the following procedure.
4) Check the difference (distortion balance) between left-hand
and right-hand side images distortions.
Lc
There is no difference
between the distortion on
the right and that on the left.
If Lc = Ld, the distortion on the left is equal to that on the right.
(The distortions are balanced.)
If the above condition is satisfied, go to the procedure 6).
If not, perform the following procedures.
MX-5001N ADJUSTMENTS 5 – 28
Scan image (main scanning direction)
distortion adjustment
L
L
Copy A
Ld
There is some difference
between the distortion on
the right and that on the left
Lc Ld
L
L = 10mm
Lc
Copy B
Ld
Lc Ld