Homebrew PCBs

----- Original Message ----- 
From: "Stefan Trethan" <stefan_trethan@...>
To: <homebrew_pcbs@yahoogroups.com>
Sent: Wednesday, January 07, 2004 10:26 PM
Subject: Re: [Homebrew_PCBs] Xerox printers?


>
> >>
> >> Hi Leon.
> >> This fascinates me.  I too tried to run a PCB straight through the
> >> office laser printer (yes, trying to get them to buy a new one)... I
> >> found that the toner didn't stick to the copper...of course, no
> >> charge would mean the toner particles wouldn't cling to it.
> >>
> >> So are these older Xerox copiers still available?  Do they require a
> >> bunch of now hard to find supplies to operate?
> >
> > It was about 35 years ago when I last saw any of these machines, so I
> > doubt
> > if any are still around. The case was made of wood! I suppose you could
> > make
> > your own from scratch, like Chester Carlson (the inventor of the
> > Xerographic
> > process) did. The tricky thing is the selenium-coated plate, everything
> > else
> > is standard optics and electrical stuff. If you look at Carlson's
> > original
> > patents, you will see exactly how they worked. I think he used a rabbit
> > fur
> > brush to remove the excess toner from the plate. The developer was
> > 'Ottawa
> > sand' (uniform particle size) coated in a special resin that held a
> > static
> > charge.
> >
> > Leon
>
>
> couldn't you use mostly parts from a complete copier?
>
> Will the selenum coating break if you try to unroll a photodrum?

Yes, it's brittle stuff. It's actually a semiconductor - the Se is doped
with As, and other stuff, IIRC. It's quite toxic, like As. The Xerox drums
were made of cast aluminium and we had a lot of trouble with coating getting
chipped and scratched by operators when cleaning the machines.

Leon
--
Leon Heller, G1HSM
Email: aqzf13@...
My low-cost Philips LPC210x ARM development system:
http://www.geocities.com/leon_heller/lpc2104.html