Homebrew PCBs

Stefan wrote:
> 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?

Black magic :-)  I understand it took many years of development to get
from idea to working Xerox copier.

For that matter, how does an electrostatic precipitator work?  Say a
dust particle picks up a positive charge and is attracted to a negative
electrode.  As soon as it touches the electrode, it should get a
negative charge and be repelled from the electrode, right?  Why do the
dust particles continue to stick to the electrodes, which are typically
clean bare metal, no glue or anything to hold the dust on the
electrodes?

Cheers,
- Jan