Same type of issue with a Samsung SCX-4623f. It worked flawlessly in 11.04 and 11.10. I tried it from to different computers, one running 32 bit 12.04, and the other running 64 bit. I also have ia32-libs installed already. So that's not the cause.
The behavior is sporadic. At first it would print the first copy, but not the others. Then it wouldn't print at all. I tried logging in and out, re-installing the driver. Unplugging, and reconnecting the printer.
I connected it to a Win XP VM, and it printed without issues.
I think Canonical needs to rethink their release system. It's seems they're in a hurry to push the new releases out on time, rather than making sure they're working first. Of course it's my fault, really, for upgrading so soon after the release date. Foolish.