Epson 836XL - Manual (Page 95)

Troubleshooting Page 95
Calculating the Adjustment Angle
If you need to adjust the document guide angle, you first need
to determine which way to adjust it and by how much.
To determine the amount you need to adjust the pin to align
your document, subtract the bottom scale value from the top
scale value and divide the result by 4. In our example,
calculate (4.0 – 3.6)
÷
4 = 0.1. Therefore, you must set the
adjust pin angle to 0.1.