sane-find-scanner and get:
found USB scanner (vendor=0x04a9 [Canon], product=0x2220 [CanoScan]) at libusb:002:002 # Your USB scanner was (probably) detected. It may or may not be supported by # SANE. Try scanimage -L and read the backend's manpage.
scanimage -L tells me:
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).
The list of supported scanners says it is the same manpage as plustek.
My canon.conf file contains:
#canon.conf #usb [usb] 0x04a9 0x2220 device /dev/usbscanner
Anything else I should try ?