[GreenKeys] [External] Re: History of printing machines

[Joe Duszyński]

Thermofax!!! we had one of those before our copy machine. you could keep
your coffee warm on the exhaust outlet.


On Tue, Mar 8, 2022 at 6:38 PM Jones, Douglas W <douglas-w-jones at uiowa.edu>
wrote:

> On 8 Mar 2022 at 11:59, Harold Hallikainen via GreenK wrote:
>
> > 4. At one time I tried gelatin printing with a tray of Jello. That did
> not work very well.
>
> Ah for the days of the hectograph.  My mom had a hectograph.  The
> "machine" was a stamped tin tray with close fitting lid, only about 1/4
> inch deep and big enough to comfortably hold a sheet of typing paper.  It
> came filled with gelatine.  To use it, you carefully melted the gelatine to
> erase the previous print run and create a clean new surface.
>
> You typed up or drew your original on something like a ditto master (I
> think it actually used the same ink chemistry), and then carefully spread
> the master face down on the gelatine and gently pat it down.  Did you have
> to pour some alcohol on the back of the master?  I vaguely recall something
> like that.  Anyway, having transferred the ink to the gelatine, you peeled
> off the master and gently lay a piece of clean paper on the gelatine and
> pat it down, then peel it off and repeat for as many copies as you can get
> before the ink fades to being unreadable.
>
> I used my mom's hectograph to print "The Neighborhood Gossip" some time
> around 1966, a childhood venture in journalism.  We did our printing on the
> dining room table, a nice oiled teak table, Scandinavian modern.  The one
> printing goof I remember was setting a fresh copy face down on the table
> top and forgetting it for a few minutes.  Oops.  That copy remained
> slightly legible, in mirror image print on the wood, for a decade or so.
>
> Another forgotten print technology:  Thermofax.  Back before photocopiers
> were cheap enough for a small department to afford, we had a thermofax
> copier.  Insert the original, a thermofax master (like carbon paper) and a
> sheet of typing paper, as a 3-layer sandwich, into the copier.  A roller
> pinched the sandwich against a rolling lamp.  Black ink on the original got
> hot enough to melt the ink on the master and transfer it to the typing
> paper.  White paper on the original didn't get hot enough, so you got a
> copy.  We used this to make individual copies of typed or handwritten (in
> dark ink) originals, but it also worked to transfer ditto ink to paper
> ditto masters that could then be used to make multiple blue (and
> alcohol-smelling) copies.  Note that Thermofax was not a telefax
> technology, you were making a facsimilie locally, not transmitting one.
>
>             Doug Jones
>             jones at cs.uiowa.edu
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