I have this troubleshoot when scanning with my HP Photosmart 5520 using scanimage (same problem with xsane though) :
If I scan with no selection area, then it's fine, I get everything. But when I set an area (via -x -y for example), there are 5 to 7 millimeter missing at the left and the top, and I can't figure out why ( I also tried to pass -l 0 and -t 0 but no changes) ...It's kind of boring having to wait the whole scan while I just need a specific area...
Any ideas ?