Sharp AR-BC260 Service Manual page 104

Main scanning direction image position adjustment (Print engine section)
(1) How to read the fine adjustment pattern
The highest-density area of the color is regarded as the center and as the reading value of the shift amount.
(The reading value in the figure below is 4.)
(2) How to read the rough adjustment pattern
Judge the polarity by checking that the color line is shifted to the positive or the negative side.
The scales are made with the black line at the center as 0, the first mark as 20, the second mark as 40, and the third mark as 60.
The interval between rough adjustment marks is 20.
(For an example shown in the figure below, it is between 20 and 40 on the positive side. Therefore, the reading value is 20.)
(Example)
9 8 7 6 5 4 3
Target adjustment range
(3) How to calculate the adjustment value
New adjustment value = Current adjustment value + Rough
adjustment pattern reading value + Fine adjustment pattern read-
ing value
A: Current adjustment value
B: New adjustment value
X: Fine adjustment pattern reading value
Y: Rough adjustment pattern reading value
Example
A: Providing that Current adjustment value = 48:
1) When Y ≥ 0, and X ≥ 0:
9 8 7 6 5 4 3
B = A + X + Y = 48 + (4) + (20) = 72
2) When Y ≥ 0, and X < 0:
9 8 7 6 5 4 3
B = A + (X + 20) + Y = 48 + (–6 + 20) + (20) = 82
2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9
(–2 to 2)
2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9
2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9
AR-BC260 SETTING AND ADJUSTMENTS 8 - 11
First mark
Second mark
Second mark
First mark
The polarity of the calculation differs depending on the polarity of
the adjustment pattern reading values. There are following four
cases:
1) When Y ≥ 0, and X ≥ 0:
B = A + X + Y
2) When Y ≥ 0, and X < 0:
B = A + (X + 20) + Y
3) When Y < 0, and X ≥ 0:
B = A + (X – 20) + Y
4) When Y < 0, and X < 0:
B = A + X + Y
Third mark
60
-60
Third mark
60
-60
60
-60