Just thinking about this pcb making.
What if an old Lexmark ( or whatever ) inkjet could be modified to pull a plain piece of heatproof board through ( instead of paper ) and the print head replaced with a nozzle pushing out tiny drops of copper in a solution or paste.
It would probably have to be very slow, but then the board could be flash heated to remove any solution, and fuse the copper particle together ?
Just excercising the brain before a busy day 