Ubuntu 16 is a long way from 13, and 18 is current.
I'd dump a ppd into CUPS and go with that, of course a ppd is hard to come across, you can typically rip one out of the Mac or Windows installer, but Xerox hides them with extensions like blah.pp_ instead of blah.ppd
So here is one from the Mac installer modified with the proper ppd extension that should work (I installed it just fine on a Mac 10.8 as a test of the theory after extracting the files on 10.15)
Hello!
I try to install Xerox Phaser 3020 on Ubuntu 16.04, but it failed every time.
Following the setting path on the computer I manage to "install", it sends the job to the printer, but it does not print, and its status is Idle.
The driver recommended on the Xerox website is compatible with Ubuntu 10.04-13.04.
Any sugestions are most welcomed.
Best regards,
Simona Bacaita