There's very little information available about this printer from YouTube user horseattack, other than it's completely homemade (i.e. not from a kit) and uses felt tip pens to ink out each line.
Full YouTube description:
"Lego felt tip 110" printer connected to an Apple Mac. This is not a kit you can buy and does not use mindstorms. I designed/built/coded it all from scratch including analog motor electronics, sensors and printer driver, the USB interface uses a "wiring" board."
My favorite part of this 90-second video is the little LEGO men 'operating' the printer. That or the little LEGO man on the pony, because ponies are a necessary component for any LEGO printer.
Hat tip for this one goes to my dear dad [he's awesome!--Ed.].