HOWTO: Epson Perfection 1670 Scanner
The scanner firmware comes in a file called ESFW30.BIN, which apparently is only available if you install the software on the CD-ROM provided with the scanner. Unfortunately, the software only installs under Windows and then you have to copy the software from the Windows machine to the linux machine. Or you can follow this simple process to download the firmware (provided by Jeff Silverman) and then update your /etc/sane/saned.conf
$ wget http://www.commercialventvac.com/~jeffs/ESFW30.BIN
$ sudo cp ESFW30.BIN /etc/sane.d
Edit /etc/saned.d/snapscan.conf and change the line…
…to point to /etc/sane.d/ESFW30.BIN
$ scanimage -L
You should see that your scanner is now detected. If so, you can now scan using XSane.