If you've rebooted and voila, the 'add printer' dialogue in print settings does not see it, I made it work---once, and one time only---by entering the ip address of the printer in the 'enter address here' box in that dialogue.
I got that from (can't remember) some IF command.
Reasonably sure if your device is on and usb plugged in than it can be identified in terminal (lspci? blkid?)--
--shakin off some cobwebs here, but trying to get you in the right direction.