Jan Kok wrote:
> 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
The drum coating is a high insulator to hold the charge in place and then
have the laser only discharge parts of it. Should be a much better insulator
than the corona wire charge can do by default. Even though the charge
'equalizes' it may still do so by pulling the toner and charge off the drum,
which is clearly how it happens for it to work..
>
> because
>
>>they would not have one then.
>>
>>Damn, i don't know.
>>
>>How does this really work?
Um, DUH, I should have thought of this sooner, I used to use this site quite
a bit for a memory refresher when discussing such topics. Haven't looked at the
site in a while though so forgot. Seems a bit slow right now though. Near the
bottom table of contents the 'Lots more information' looks promising.. :) I
think we could all stand a bit of reading just to clarify, I know it's been a
while since I looked at the process fully. Damn I want to find the printer they
used for their first page drawing now, punch a hole in the back and it's nearly
perfectly straight, could do copper board.
http://computer.howstuffworks.com/laser-printer.htm Looking more this is a very good page, as are most of their's..
>
>
> 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
Remember it's not one atom and many things are highly insulative. You can
easily have it hit, that side charge the other way, and still the whole overall
particle is still attracted by the rest of its charge. The whole reason the
dust has a basic charge in the first place is it's so insulative, and some of
the electrons are stripped away when it seperates. You don't get much of a
charge on metal flakes etc. Even if a few electrons are stripped as it's being
seperated, they move back around through the metal and flake and even out until
the very last point of contact is lost. Most things like paint etc that use
electrostatic processes are good insulators, only the base object being painted
is a conductor.