Archival storage

[Tony Duell]

> 
> > 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 
rolled.

-tony