AR-M550 (serv.man14). (7) Settings and adjustments - Sharp Copying Equipment Service Manual (repair manual). Page 11

AR-M550/M620  SETTING AND ADJUSTMENTS  7 - 11

If there is some distortion in the sub scanning direction, do the follow-
ing steps.

4) Loosen either of two fixing screws of the scanner unit drive pulley.

(Either one on the front or the rear side will do.)

5) With the scanner unit drive shaft kept stationary, manually turn the

scanner unit drive pulley to change the parallelism of Scanner
Units A and B. (Change the positional relationship between the
scanner unit drive pulley and the drive shaft.)

6) Tighten the scanner unit drive pulley fixing screw.

Repeat steps 2 to 6 until an acceptable result is obtained. 

If the above steps fail to eliminate distortions in the sub scanning direc-
tion, do the steps described in "ADJ 6E: Adjust scanned image distor-
tions in the main scanning direction - 2."

This adjustment is needed in the following situations:

• The scanner (reading) section has been disassembled.

• Scanned images are distorted.

1) Make a test chart on A3 (11" x 17") paper as shown below. (Draw a

rectangular with four right angles.)

2) Set the test chart made in step 1 on the document table, and make

a copy on A3 (11" x 17") paper.

3) Check for distortions in the main scanning direction.

If the four angles of the rectangle on the copy are right angles,
there is no distortion and therefore  no further steps are needed.

If there is some distortion in the main scanning direction, do the follow-
ing steps.

4) Check the difference (distortion balance) between left-hand and

right-hand side images distortions.

If Lc = Ld, the distortion on the left is equal to that on the right. (The
distortions are balanced.) 

If the above requirement is satisfied, then do the steps described in
"ADJ 3E: Adjust scanned image distortions in the main scanning direc-
tion - 2."

If the above requirement is not met, then do the following steps. 

5) Change the height balance of the front frame side scanner rail.

• If the paper leading edge is more distorted than the paper trailing

edge, then raise the scanner rail right side. 

• If the leading edge is less distorted than the paper trailing edge, then

lower the scanner rail right side.

6) Set the test chart made in step 1 on the document table, and make

a copy on A3 (11" x 17") paper.

7) Check the image distortion balance in the main scanning direction.

Repeat steps 5 to 7 until the difference in size of image distortion (dis-
tortion balance) in the image scanning direction is equal.

L

L

L

L

L = 10mm

Lc

Ld

Lc

Ld

Copy A

Copy B

There is no difference 

between the distortion on 

the right and that on the left.

Lc = Ld

There is some difference 

between the distortion on 

the right and that on the left.

Lc 

≠

 Ld