If they don't support SNMP or worse, you don't run it. You can't tell my user ID, but if you're feeling "techy" you can put any sniffer in the same broadcast segment with the printer and filter the packets for it's IP, then cross reference the source IP Address to the machine, match the time to the user login....pain in the neck, but depending on your infrastructure, or the lack thereof......how badly do you want to know?
if you have zerox, high end type printers, print a menu map from the console of the printer and find the submenu that will print what you want to know. This can be cleared by anyone that has access to the printer, but they have to know it's there, and truly not want you to know what they've printed.
Good Luck.