Printing a lot of pages with wierd signs, which I call gibberish, means that the printer is printing the raw printer code, PCL or PostScript versus creating the image from the PCL or PostScript.
I did a quick Google seach and it looks like many are having issues printing on Ubuntu after upgrading to varouse versions of Ubuntu and it's not just Xerox. This link may help you troublehoot your issues, https://wiki.ubuntu.com/DebuggingPrintingProblems.
You don't specify how you are printing, USB, wireless, or a direct network connection so the link referenced above is probably the first place to start.
If you were printing over a network, wired or wireless, I would suggest taking a PDF file and sending to the printer using the LPR command. http://manpages.ubuntu.com/manpages/cosmic/man1/lpr.1.html.
If that prints fine, I highly doubt is the printer.
