simple scan can't find epson RX640 scanner

install libsane-extras

according to this site it will make it work using
http://manpages.ubuntu.com/manpages/jaunty/man5/sane-epkowa.5.html

sane-epkowa

You may also want to use the files here:
http://www.avasys.jp/lx-bin2/linux_e/spc/DL1.do

Hello and thanks for response.
I've installed libsane-extras and latest scanner drivers from avasys.
the scanner is now discovered by XSane but with opening error on 'epkowa:usb:001:003 source access refused
gscan2pdf find an unknown scan and stucks in update
Simple-Scan see an unknow scan and can't be connected to it.

maybe I should control if the scan is OK.

Try:

gksudo simple-scan

see if its nicer

yes it works and gives the good name RX640.
I add myself to xsaned group but it doesn't work.
still have too use gksudo...

and can I go through gksudo ?

Sure, if gksudo makes it work then I'd run with it. You may want to check the ownership of the files it makes, you may find they are owned by root but we will see. You can find out with:

ls -la file.jpg

Obviously replace file.jpg with the filename of a file you have created with the scanner. You may have to add yourself to the saned group too. I'm only guessing here. I don't use scanners.