A bit of work, but install the scanner on a new system, scan some images and looke for what is done.
cloudy,
If this was the case would there be any evidence files on the computer showing this????
Maybe grab a copy of the scanners supplied software and see where it would save files, what format they take (the image recorded may be proprietary format ) etc.
if they bypassed the PC altogether
do you have seized counterfeit notes ? you maybe able to tie them to a particular scanner or printer via analysis of noise marks (scratches on the glass / inkdrum etc) or colour analysis of the inks on paper, or the slight percentage size error.
Do a google or yellow pages for scientific analysis firms, or checkout www dot docev.co.uk under "guides for the investigator"
Kern