The accuracy which [Mario] achieved in his pen plotter dot matrix printer is very remarkable. He tore through a pile of floppy drives to get the parts he wanted, and chose to go with a fine-point Sharpie marker as a print head. In the video after the break he flatters us with a printout of the Hackaday logo, but you also get a look at one problem with the build. The ink doesn’t always flow from the felt tip and he has to coax it (almost like priming a pump) with a piece of scrap paper.
He was inspired by the pen printer we featured back in June. This rendition features a printing area of 1.5×1.5 inches that can accommodate 120×120 black and white pixels. He’s not a microcontroller type of guy and is driving the printer from the parallel port of his computer.
The best printing technique puts the pen down and moves it around just a bit (helps prevent the ink flow problem we mentioned earlier) and produces images like one in the lower right. We love the 8-bit nature of the result and would use this all the time to make our own greeting cards.