I'm not sure if this is the right SE network to ask, but here goes:
Consider the following picture. This would be a closed closet in which a printer is mounted. Requests can be sent to the printer via USB/Ethernet/Whatever. The printer would then print its paper through slits in the closet, similar to how a label printer might work.
Ideally, the printer would be multilayered and able to support different paper types. So the top layer could be A4, the bottom layer A5.
Is there a printer that does this? I've stumbled upon "POS printers", but these seem mostly label printers for stores.