[GreenKeys] More on the TTY ribbons?

[Doug Alderdice]

At 03:22 PM 8/10/2011 -0700, Bill wrote:
>I think it was my 3rd or 4th ship that we finally got a "copy machine".
>It was a thermal transfer system. You would put the TTY copy inside a
>two part sleeve - the 2 parts being a clear cover and the purple media.
>This would be inserted in to a thermal unit that would shine an intense
>light on it and make an image of the message onto the purple media. We
>would then take the purple sheet off and put it on the "ditto" machine
>and run copies. By the end of your 8 hour watch, you were purple from
>head to toe.
>
>It seemed like the transfer system would only work with a carbon based
>ink or at least something that had some carbon in it. A pencil would
>work but a blue ink pen would not. Or maybe it was just that it needed
>something black.

We used to call those machines "Thermofax" machines and had a few in the 
school.  Not sure if it was a trademark name or just the process.  It 
worked with carbon-based inks, so like you said it would work with pencil 
but not pen.  In the early days of laser printers, I'd make ditto masters 
from laser printer output because the carbon-based toner in the printers 
was perfect for the Thermofax machines.  I could get some really great 
ditto masters from those.  The master sets we used came as a complete unit, 
you inserted your original in the packet and ran it through the machine and 
after it came out you took out your master and peeled off the purple layer 
leaving you with the ditto machine master, and stayed relatively clean.

The thermofax machines also could be used with special transparencies that 
reacted to the carbon-based inks and I used the Thermofax more for making 
overhead transparencies than for making ditto masters.  I think the 
Thermofax lamp produced a ton of intense infrared light which made whatever 
reaction happen with the media you were using, the machines would get quite 
hot quickly and had a bunch of fans in them.  There was a speed setting on 
them for how fast the media would go through the machine.  Can't remember 
what went slower or faster, the transparencies or the ditto masters.

Gad, ancient technology!  But then, that's what we're all about here, isn't 
it? ;)

73,

Doug, KA2WFT