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Electrostatic Charge

Inkjet Printer.

An inkjet printer uses electrostatic charge
to direct the ink to the correct place on the page.

Coloured ink is passed through a very small hole (called a nozzle)
which separates the ink into many tiny droplets.
The tiny droplets are given an electrostatic charge.

The direction in which the charged ink droplets move
can be controlled by electrically charged metal plates.
A voltage on the plates means that the charged ink droplets
will be attracted to one plate and repelled by the other.
This is very similar to an "electron gun" or "cathode ray oscilloscope"
where an electron beam is directed to a particular place on a screen.

In the picture below, the ink droplets have a positive charge.
The are attracted to the negative plate and repelled by the positive plate.

Inkjet Printer Nozzle

By controlling the voltage on the plates
a particular ink drop can be precisely positioned on the paper.
There are many nozzles,
and the final picture is made up from a very large number
of coloured ink drops, each in exactly the right place for the image.

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Copyright © 2008 Dr. Colin France. All Rights Reserved.