My computer previously ran Ubuntu 10.4. After upgrading to 13.4, my Epson scanner no longer can be found by the system. Following documentation, I find the following:

$ 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 open USB device 0x046d/0x082b at 001:007: Access denied (insufficient permissions)
...
  # No USB scanners found. If you expected something different, make sure that
  # you have loaded a kernel driver for your USB host controller and have setup
  # the USB system correctly. See man sane-usb for details.
...

If I instead run sudo sane-find-scanner, I get

$ 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.

found USB scanner (vendor=0x04b8 [EPSON], product=0x0131 [EPSON Scanner]) at libusb:001:009
could not fetch string descriptor: Pipe error
could not fetch string descriptor: Pipe error
  # Your USB scanner was (probably) detected. It may or may not be supported by
  # SANE. Try scanimage -L and read the backend's manpage.

So what do I do? scanimage -L does nothing for me and I don't know what the "backend's manpage" might be. It's seems likely that this is a permissions issue since the scanner can be found as root, but I don't know how to solve it. Can someone help?