Scanner support in ROSA is provided by drivers from sane-backends, sane-backends-iscan and hplip packages. Lists of scanners supported by version of sane-backends used in particular ROSA release can be found at the Sane project site.
If your scanner is not included in that lists, please take a look at lists of devices supported by sane-backands snapshot version. You can also take a look at the list of backends not included in the sane-backends package for some reasons (e.g., licensing issues).
If you have found your device in that additional lists, feel free to contact ROSA developers using forum or mailing list - we will try to update/add necessary drivers, if this is possible.