Epson GT-12000 User Manual page 42

8. See the left edges of the scales of the scanned image. Every
line of the scale that is missing is equal to 0.4 for
mathematical purposes. Then calculate the adjustment
angle using the following equation.
The adjusting angle = (scale A - scale B) / 4
For example:
If scale A starts at line 0, then 0 x 0.4 = 0; the value for
scale A = 0
If scale B starts at line 2, then 2 x 0.4 = 0.8; the value for
scale B = 0.8
(0 - 0.8)/4 = -0.2
The angle you need to adjust the adjust pin = -0.2
9. Turn the arrow on the adjust pin to the number indicated by
the calculated result (-0.2 in the example above).
10. To confirm this angle, repeat steps 3 to 8. EPSON
recommends you record the adjust pin's position for future
reference.
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