A co ti řekne tohle /usr/sbin/scanimage -L
/usr/bin/scanimage -L

říká to tohle:
/usr/sbin/scanimage -L
bash: /usr/sbin/scanimage: Adresář nebo soubor neexistuje
/usr/bin/scanimage -L
No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).