With the update of sane package to version sane-1.0.18-3.pkg.tar.gz, the scanner is not accessible any more, "no device available" (my translation of German error message "keine Geräte erreichbar".

I have the following output of "dmesg":
usb 3-1: new full speed USB device using ohci_hcd and address 2
usb 3-1: configuration #1 chosen from 1 choice
usb 3-1: usbfs: interface 0 claimed by usbfs while 'xsane' sets config #1
usb 3-1: usbfs: interface 0 claimed by usbfs while 'xsane' sets config #1

With the previous version sane-1.0.18-2.pkg.tar.gz, everything was ok (see http://bbs.archlinux.org/viewtopic.php?id=31803). After downgrade to that version, the scanner is accessible again.

Perhaps the problem only occurs with several devices connected via usb, e. g. I have a printer on another usb port and a card reader on a third usb port.

lsusb:
Bus 003 Device 002: ID 04b8:010b Seiko Epson Corp. Perfection 1240
Bus 003 Device 001: ID 0000:0000
Bus 002 Device 001: ID 0000:0000
Bus 001 Device 003: ID 05e3:070e Genesys Logic, Inc.
Bus 001 Device 002: ID 04a9:10b6 Canon, Inc.
Bus 001 Device 001: ID 0000:0000

Bus 003, device 002 is the scanner,
bus 001, device 003 is the card reader,
bus 001, device 002 is the printer.

Problem had not been resolved with actual sane version sane-1.0.18-4.pkg.tar.gz