Epkowa

What is it?
Proprietary driver for some Epson scanners.

Why might I need it?
Your scanner is not supported by standard SANE backend.

SANE supported scanners list your scanner as supported by epkowa driver.

How does it integtate with Gentoo?
Installed as part of media-gfx/iscan which is an Epson scanner utility, like xsane without many of the bells and whistles.

Requires proprietary firmware plugin for relevant printer.

Plugins can be installed using media-gfx/iscan-plugin*

Plugins have a dependency on media-gfx/iscan and media-gfx/iscan-data

Once installed it can be used by other scanner utilities such as xsane and scan-image in the same way as any other SANE backend.

Issues with media-gfx/iscan-data
media-gfx/iscan-data currently broken (see bug).

Workaround (see also suggestions in bug reports)
Check dependencies of iscan-plugin*  and emerge these separately.

For iscan use --nodeps to avoid pulling in iscan-data which will cause build to fail.

Emerge you plugin using --nodeps to avoid pulling in iscan-data which will cause build to fail.

This should leave you with a system in which the scanner is found by scanimage -L and sane-find scanner using root account but not as normal user.

Manually adapt udev rules to add USB vendor and device id (see ref, man udev, SANE etc).