You can try to temporarily resolve via udev rule,
although this is material for bugzilla, downstream and upstream.
http://anonscm.debian.org/cgit/sane/sane-backends.git/tree/README.linux
#n8
Permissions:
------------
While SANE automatically uses libusb when the library and its header file were
present during the build of sane-backends, setting permissions will require some
attention. So if scanimage -L lists your scanner as root but not as normal user
read on this text.
...
Canon CanoScan N1240U/LiDE30 udev rule examples
http://anonscm.debian.org/cgit/sane/sane-backends.git/tree/testsuite/tool...
http://anonscm.debian.org/cgit/sane/sane-backends.git/tree/testsuite/tool...
Arrivederci