26 Jul
2006
26 Jul
'06
8:16 a.m.
On 7/26/2006 at 9:13 AM Jim Isbell, W5JAI wrote:
The worst printer of all came before the computer. The
Datafax. It
used paper sensitive to an electric discharge (spark) and could send
signatures by wire. The paper was held to a metal drum with tensioned
springs and a stylus hovered just above the paper and an electrical
discharge jumped from the stylus to the drum through the paper. I have
a stack of them in my garage.
I believe the Sinclair ZX-81 had an option for a "spark printer". I recall
that kymographs and the like used to use that same paper for recording.
One aspect was that with an AC power supply, you coiuld get a pretty good
estimate of the pen speed by looking at the length and spacing of the dots
created by this process.
Cheers,
Chuck