Dak, in the days of dot matrix printers, marketed a horrible one in the computer mags that I simply had to have but now don't remember why. It used glass ampules filled with carbon as a print head, and a high voltage arc? to drag it to the page. It did work though, and I used it for my Atari systems at the time. Simply an odd product.
Sounds like the TRS-80 Screen Printer. A roll of aluminized paper was bent into an arc around a spinning drum with high-voltage wipers. Voltage pulses on the wipers would burn away the aluminum, revealing the dark background paper. Very fast, very strange.
Weird. 4 inches wide. Printed the contents of the screen and nothing else. Connected directly to the bus by an edge connector (no card or serial or parallel connection).
