ard at p850ug1.demon.co.uk
Wed Oct 12 11:06:47 CDT 2005
> > 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?
> This might be Readex Microprint technology. I've never seen an example
> of Readex output, although the company is a few miles from me and used
> to be a microfiche customer. I do know they got significant storage
> reduction compared to paper.
I've come across it 4 times, I think. One, as every UK collector will
realise, is the Sinclair ZX printer. Radio Shack sold something called a
Quick Printer II (or some name like that) which was similar. The UK
Magazine did a project called the 'Microprinter' which used such a print
mechansim, and I was given one of thsoe. And the last was a thing called
an 'Axiom EX820 Microplotter' which used an 7 or 8 needle head, not a
single electrode as in the ZX printer.
I rememebr experimaneting with the paper a bit (before I could afford
any sort of printer). It took a fair voltage to burn off the coating -- a
few 10's of volts at least. A 5V supply wouldn't do it. I've never seen a
schemaitc for the ZX printer, and there's a ULA in there which makes life
'interesting', but I seem to rememebr a coil/transformer on the PCB too
which might well be part of a voltage step-up circuit.
My experience with the paper is that it scratches very easily and the
aluminium coating comes off if you crease it. This causes extra black
marks on the paper. I have no idea how long it would last if carefully
More information about the cctalk