Since upgrading from Ubuntu 16.04 to 18.04 my Epson Workforce 2760 printer will not scan documents. I have tried everything I can find related to this problem with zero success. I have tried installing backends and setting permissions. There are others who are having this problem but perhaps not enough to get to a level that attracts the attention of someone who can help. There may be a bug in the 18.04 version that causes this and hopefully either a workaround or a fix can be discovered soon.
One thing I tried was this:
sudo ln -sfr /usr/lib/sane/libsane-epkowa* /usr/lib/x86_64-linux-gnu/sane
Still no success. Possibly the upgrade to Ubuntu 18.04 broke something within the Sane setup. I don't know how to "provide some more details, like the output for lsusb to prove the scanner is actually attached and recognized." Found this: https://bugs.launchpad.net/ubuntu/+source/sane-backends/+bug/1728012
Here is output of "sudo sane-find-scanner" : # sane-find-scanner will now attempt to detect your scanner. If the # result is different from what you expected, first make sure your # scanner is powered up and properly connected to your computer.
# No SCSI scanners found. If you expected something different, make sure that # you have loaded a kernel SCSI driver for your SCSI adapter.
could not fetch string descriptor: Pipe error could not fetch string descriptor: Pipe error found USB scanner (vendor=0x04b8 [EPSON], product=0x111c [EPSON WF-2760 Series]) at libusb:005:002 # Your USB scanner was (probably) detected. It may or may not be supported by # SANE. Try scanimage -L and read the backend's manpage.
# Not checking for parallel port scanners.
# Most Scanners connected to the parallel port or other proprietary ports # can't be detected by this program.