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Subject: Re: [Homebrew_PCBs] running copper sheets through laser printer

From: Stefan Trethan <stefan_trethan@...>
Date: 2004-02-26

> I don't know why it apparently works, but maybe it has to
> do with the paper or plastic insulating backing.
>
> Cheers,
> - Jan


I can only speak for my IIID and with that printer the top/pritned side is
grounded 1 cm in front of the
corona wire. the paper passes between a metal blade on the top and a
rubber roller on the bottom.

So if the paper is say halfway through the drum the last portion will
still have contace
to the metal blade, while one part is over the corona wire and another
part is already at the drum.


My guess is that it works because some of the toner is transferred from
the drum to the copper
even if there is no corona voltage present (the paper is uncharged).

I wanted to test this yesterday, but the printer refused to work when i
took out the corona wire
assembly.

Just imagine it, you have the drum, with the toner sticking to the charged
portions.
then the copper comes along, touching drum and toner.
when touching the drum is discharged locally, so there is a 50/50 chance
the toner will
stay on the copper.

hmmmm doesn't work this theory. that would mean the charging of the paper
is unnecessary because
the charge will equalize at contact with the drum.
this in turn means the corona wire is useless, which is ridiculus because
they would not have one then.

Damn, i don't know.

How does this really work?

ST