Epson 836XL - Manual (Page 81)

Troubleshooting Page 81
The edges of the document are missing from the scanned output.
Color is patchy or distorted at the edges of the image.
The image is faint or out of focus.
Problem Solution
The document is
positioned incorrectly. The document table has non-readable areas around the edges.
Reposition your document so that the image you want to scan is within
the readable area.
Problem Solution
The document may be
letting in external light. If the document is very thick or warped at the edges, the edges of the
image may be discolored. Cover the edges of the document with
opaque paper to block outside light.
If part of the document extends beyond the document table, that edge
may not be in contact with the document table. Change the position of
the document.
Problem Solution
The document is not
placed correctly. Check that the document is placed flush against the document table.
Your software settings
may be incorrect. Adjust the brightness option in your software to a darker setting.