Есть МФУ Samsung SCX-3405, подключенное к принт-серверу на дебиане. Сканирует нормально, но после простоя перестаёт определяться как сканер:
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).
sane-find-scanner -q
found USB scanner (vendor=0x04e8 [Samsung Electronics Co., Ltd.], product=0x344f [SCX-3400 Series]) at libusb:002:004