Re: Not the Internet?
I don't believe the printer includes the date, time or location.
What it does include on modern laser printers is the serial number encoded as a yellow dot pattern so that prints can be traced to the machine that printed them. You need a x25 magnification tool to see it. You may be able to get around this by printing in mono as the transfer belt is (usually on Ricoh devices) moved away from the colour units to reduce wear.
The reason that this was implemented was to be able to trace fake currency to a specific printer. Other manufacturers can prevent copying of currency, i believe KM / Olivetti went down this route at one point. The rumors about it bricking the machine dissuaded me from giving it a go.
Ink jet on the other hand, no idea as I hate the things.