Sharp AR-M236 Service Manual page 36

(7) Sub scanning direction (scanning direction) distortion
adjustment (Winding pulley position adjustment)
This adjustment must be performed in the following cases:
• When the mirror base drive wire is replaced.
• When the lamp unit, or No. 2/3 mirror holder is replaced.
• When a copy as shown is made.
La
Paper exit
direction
Original
1) Set A3 (11" x 17") white paper on the original table as shown
below.
Place a little clearance from
the rear side original guide.
Glass holding plate
Fit the paper edge and
the glass holding plate edge.
2) Open the original cover and make a normal (100%) copy.
3) Measure the width of the black background at the lead edge and at
the rear edge.
Paper exit direction
La: Lead edge black background width
Lb: Rear edge black background width
If the width (La) of the black background at the lead edge is equal
that (Lb) at the rear edge, there is no need to execute the following
procedures of 4) – 7).
Lb
Copy
A3 (11" x 17") white paper
AR-M236/M276/M237/M277 ADJUSTMENTS 7 - 6
4) Loosen the mirror base drive pulley fixing screw on the front frame
side or on the rear frame side.
• When La < Lb
Turn the mirror base drive pulley on the front frame side in the
arrow direction A. (Do not move the mirror base drive pulley shaft.)
• When La > Lb
Turn the mirror base drive pulley on the rear frame side in the
arrow direction A. (Do not move the mirror base drive pulley shaft.)
Front side
5) Tighten the fixing screw of the mirror base drive pulley.
<Adjustment specification>
La = Lb
6) Execute the main scanning direction (FR) distortion balance
adjustment previously described in 2) again.
(8) Main scanning direction (FR direction) distortion
balance adjustment (Rail height adjustment)
When there is no skew copy in the mirror base scanning direction and
there is no horizontal error (right angle to the scanning direction), the
adjustment can be made by adjusting the No. 2/3 mirror base unit rail
height.
Before performing this adjustment, be sure to perform the horizontal
image distortion adjustment in the laser scanner section.
This adjustment must be performed in the following cases:
• When the mirror base wire is replaced.
• When the copy lamp unit and no. 2/3 mirror unit are replaced.
• When the mirror unit rail is replaced and moved.
• When a following copy is made.
Original Copy A
1) Make an original for the adjustment.
Make test sheet by drawing parallel lines at 10mm from the both
ends of A3 (11" x 17") white paper as shown below. (These lines
must be correctly parallel to each other.)
Parallel line
10mm
10mm
2) Make a normal (100%) copy of the test sheet on A3 (11" x 17")
paper. (Fit the paper edge and the glass holding plate edge.)
Rear side
A
B
Copy B
Parallel line
10mm
10mm
White paper