photocopier

[toniscarrow3]

who invented the photocopy machine?

[bird_81]

http://www.inventhelp.com/Chester-Carlson-and- the-Invention-of-the-Photocopier.asp

[demhot]

The photocopier started its development in the early 1800's. Common projection copiers include the copy camera and the photostat machine. A copy camera takes a photograph of the original. The film is then developed producing a negative to make a positive copy. Copy cameras, like all projection cameras, can enlarge or reduce the size of the copy made from the original. This feature makes them valuable in commercial art and many other fields..
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From wet to dry photocopying
Electrostatic photocopying was invented in 1938 by Chester. F .Carlson, an American Physicist. Unlike the earlier methods which require liquid chemicals, photocopiers were completely dry.This type of photocopying is known as 'Xerography.'

'Xeros' in Greek means 'dry' and 'graphy' means writing.


How photocopiers work
Photocopiers work like this:

1 A drum is coated with light sensitive material charged with static electricity.

2 Light is reflected from the original through a lens.

3 A positively charged image forms on the light sensitive surface.

4 The toner gets dusted on the drum and sticks to the image.

5 The image is then passed onto positively charged paper and heated for a moment.

6 The heat melts the toner and creates a copy.
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