I was wondering about making a bip38 encrypted paper wallet, but I have the worry of the QR codes being kept somewhere during the printing process, maybe in some kind of temporary file that I don't know of. I want to be sure that I completely delete the file that has the private QR code from my hard drive, so I will use the program called Eraser. The problem is, I don't know if when you print something, the file you are printing, like I said before, gets stored temporarily in other folder, or something like that, or even on the hardware of the printer? somehow. But I doubt it, my printer is a pretty old HP one, so I doubt it has the ability to store stuff.
I hope my question makes sense, if not then I can try to rephrase it.
1-Yes, every computer saves print files somewhere, and this is true regardless of the type of computer.
Furthermore, even if you're not printing from PC, the printer itself has memory, and does store files. Only old printers didn't have memory, but rule 1 still applies.
Your best bet would be purchase a shopping confirmation leaf printer, but research for a specific printer type that is secure in this way (many aren't)
Alternatively, if you do it manually, just put a piece of light paper on your monitor and with pen copy the QR code with private key on the paper with dark color. You can print the grid with three corner rectangles and will be very secure.