It's simpler to just remove your hard drive and use a live OS, especially Tails, since Tails will automatically delete all session data. And I would never print a private key, who knows what sorts of backdoors and security vulnerabilities a printer might have?
Perhaps just unnecessary paranoia but there is a way to mitigate this. Some pretty cheap printers has no capabilities to connect to the internet and would thus not be able to transmit any information other than through the cable. Printers do store cache so I imagine that'll be an issue. If you really are that paranoid, you can destroy the printer after use/use it exclusively for paper wallets.