The single hardest part is the print head. If you can reuse an existing one, and you can, then you're most of the way there. The paper path itself is mechanica

The single hardest part is the print head. If you can reuse an existing one, and you can, then you're most of the way there. The paper path itself is mechanically involved, but not to an impossible degree - it's hard to make it work, but it's not MEMS magic, it's manufacturable in the same way advanced 3D printers are manufacturable.