This is proving a lot more complicated than expected... Matching up the ink with a compatible cartridge distribution mechanism is beyond the scope of my own expertise. I'm electrical, not a chemical engineer.
That said though, conductive ink pens exist, and older pen plotter printers exist. Should be much easier to adapt the pen to the printer. It won't be as high-res as a more modern ink-jet printer, but it should work. Proof of concept is all I'm aiming for at this point.