Epson GT-12000 User Manual page 69

If your document is in landscape orientation (meaning
the top and bottom edges are longer than the side
edges), insert the document with the left edge closest to
the document feed path.
Note:
Make sure the side of document you want to scan faces up.
If you load multiple pages in the Auto Document Feeder, the
Feeder will feed from the bottom.
To automatically scan both sides of a document, make the
Double-side setting in EPSON TWAIN Pro.
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