Comment 7 for bug 180932

Matthais: yeah, I also had to add "scanner" to my users groups, however, udev creates the scanner device with the owner:group root:root, when it should have been "root:scanner".

The solution is to add your user to the scanner group, then find what bus your USB scanner is on with "lsusb" (you get a number like 002:004), then

sudo chown root:scanner /dev/bus/usb/002/004 (or what ever the numbers are)

I have to do this every time I plug in the scanner, or turn on the computer.