13 Oct
2005
13 Oct
'05
12:42 a.m.
Chuck Guzis wrote:
Back when small printers were hard to come by, there was at least one technology
that used a "paper' made of a black layer on a paper substrate covered by a
very
thin layer of aluminum. The printer burned through the aluminum, leaving the black
spots exposed. Oddly enough, this sounds like a fiarly permanent process. Was the
stuff called "electrographic" paper?
The Canon EP151 calculator used this technique as early as 1971.
A rotating stylus is fed with 120 VDC driven by the output of an
early MOS character generator ROM.
Even earlier though: Western-Union/Seeburg TeleFax FAX machines circa 1960 used
the technique. The paper is placed on a rotating drum for scanning and output.
The output paper is similar to carbon paper with an additional aluminised coating
or an aluminum-carbon amalgam.
All tubes. Signal is analog, mechanically chopped for Pulse-Amplitude-Modulation
transmission over the telcom line.
(.. got two of them, but they don't work simply connected back-to-back, have to
figure out what was in the 'cloud' in between, someday.)