From ArchWiki

Sane provides a library and a command-line tool to use scanners under GNU/Linux.

[edit] Setup

• Check if sane supports your scanner.
• Open a root terminal.
• Install sane.

pacman -S sane

• Users that need to use a scanner should be part of the group scanner. Use gpasswd to add a user to a group:

gpasswd -a username scanner

• Try to see if sane recognizes your scanner

scanimage -L

If that fails, check that your scanner is plugged into the computer.

• Do not forget to logout/login after gpasswd -a username scanner.
• You might have to unplug/plug your scanner for /etc/udev/rules.d/sane.rules to recognise your scanner.

[edit] Firmware

This section is only needed if you need to upload firmware to your scanner.

[edit] Extract the file from your scanner install CD.

If you use a Windows install CD, you may need to get the firmware from an .exe file.

The .exe may just be a zip archive. Install and run unzip.

pacman -S unzip
unzip file.exe

The firmware may still be inside a .cab archive. To extract the contents from a .cab archive, install and run cabextract.

pacman -S cabextract

If you don't have an install CD, you might find the required software on the scanner manufacturer's website.

• Make a directory firmware in the /usr/share/sane directory and place the firmware there. Be sure that members of the group scanner can read the file.

• Find the name of the backend for your scanner from this list. Open the file /etc/sane.d/<backend-name>.conf. Uncomment the firmware-entry and let the file-path point to where you put the firmware-file for your scanner. Be sure that members of the group scanner can access the <backend-name>.conf file.

Normally, everything should be OK.

(What about hotplug and firmware-upload?)