[sane-devel] hp5590 driver and ADF

Joel hashbang at gmail.com
Wed Sep 16 16:23:48 UTC 2015

I found a discussion a while back about the ADF scans having extra
lines and spilling to the next page. Someone discovered that there is
a line on the right, with a blue dot signalling the end of the page.
Also, the end of the document is signaled by alternating white and
black pixels.

I recently acquired a ScanJet 7650, and was planning on scanning a
large amount of documents I have. For some reason, using PDFxchange to
scan in windows won't duplex at all, so that's useless for me. The
SANE driver appears to work well, but when I use the ADF, the pages
get out of sync quickly.

I've played around with it a little, and dug around in the backend
code. I've also turned on hp5590 debugging and simple-scan debugging.
It appears as if the length of the document should not be assumed/used
when using the ADF, and the in-band "blue dot" should be used.

Does it make sense for the backend to return EOF when in ADF mode and
detects the blue dot? Should it remove the line on the right, as well
as the alternating white and black? Should it also flip the even
number page 180 degrees? My thought is that these are not frontend
sort of tasks, as they are specific to this group of scanners.

I could try to implement something, but certainly need some direction.
I'm unsure of the right way to go about it.


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