Comment 9 for bug 865613

Your posted information ("lsusb" reports printer, "ls -l /dev/bus/usb/*/*" shows that UDEV has set correct permissions, but /usr/lib/cups/backend/usb does not list the printer) matches exactly with bug 872711 which I have found and reported today. It is a kernel bug which affects many printers of different brands, but not all printers.

Marking as duplicate of that bug ...