Spark printer

A spark printer uses a special paper coated with a layer of aluminium over a black backing, which is printed on by using a pulsing current onto the paper via two styli that move across on a moving belt at high speed. It was a simple and inexpensive technology which produced fairly good results. At a time when conventional printers cost hundreds of dollars, the sub-$100 price of that type of printer was a major selling point. The only major downside is that it can only print onto the special metallised paper which it uses; unfortunately that paper is no longer readily available.

That type of printer was used in the printer of an antique Casio scientific calculator also.