Sharp MX 3501N - Color Laser - Copier, Service Manual

Page: 56 / 448

MX3500N ADJUSTMENTS 6 – 11
4) Check the printed black image for any skew (right angle).
Measure the right angle level by using the six cross patterns
printed in black.
There are following two methods of checking the black image
for any skew (right angle).
Method 1: Measure the length of the diagonal lines from the
cross point of the cross pattern. Check the difference in the
length of the diagonal lines for judgment of good or no good.
Method 2: Use the right angle sides of A3 or 11 x 8.5 paper for
judgment of good or no good.
NOTE:
IN the case of Method 2, the right angle of paper to be used
may not be exact. Be sure to check the right angle of paper to
be used in advance.
(Method 1)
a) Measure the length of the diagonal lines from the cross
point of the outside cross pattern.
b) Calculate the difference between the measured lengths C
and D of the diagonal lines.
c) Check to insure that the difference between C and D is in
the following range.
C – D =
±
0.8mm
If the difference between C and D is in the above range,
there is no need to adjust.
(Method 2)
a) Fit the three cross points of the cross patterns in a row with
the side of A3 or 11 x 8.5 paper for checking for any skew
(right angle).
b) Measure the shortest distance between the cross pattern
on the extended line of the vertical line and the paper side.
If the above distance is 0.5mm or less, there is no need to
adjust.
If not, execute the following procedures.
5) Open the front cabinet, and remove the waste toner box.
6) Loosen the LSU (writing) unit fixing screws (2 pcs.) and shift
the skew adjustment screw in the arrow direction to adjust the
LSU (writing) unit skew.
(When Method 1 is used to check the black image for any
skew (right angle) in procedure 4)
When the lengths of the diagonal line are C > D, shift the
adjustment screw in the direction of Y.
When the lengths of the diagonal line are C < D, shift the
adjustment screw in the direction of X.
(When Method 2 is used to check the black image for any
skew (right angle) in procedure 4)
If the image is skewed in the arrow direction of A, shift the
adjustment screw to X direction. If the image is skewed in the
arrow direction of B, shift the adjustment screw to Y direction.
7) Install the waste toner box, and close the front cabinet.
8) Execute procedures 3) – 4).
(Repeat procedures 5) – 8) until a satisfactory result is
obtained.)
9) If the adjustment result reaches the satisfactory level, tighten
the adjustment screw.
(The black image skew adjustment is completed with the
above.)
10) In the above black image skew adjustment, check the color
image skew pattern printed when completion of the adjust-
ment.
In each Y/M/C color print pattern printed separately in the front
frame direction and in the rear frame direction, note the same
print color pattern and check to confirm that the difference in
the highest density sections is within
±
1 step.
R
F
Diagonal line D
Diagonal line C
Direction A Direction B
R
F
Comparison line
A3 or 11 x 8.5 paper
The cross patterns in a row
Reference line
0.5 mm or less
X Y
R
F
*A
*A: Rough adjustment pattern
*B
*B: Fine adjustment pattern
*B
Direction A Direction B
Magenta Cyan Yellow