B-6- XEROGRAPHY (THE PHOTOCOPIER)
        The photocopier started its development in the early 1800's. Common projection copiers included the copy camera and the Photostat machine.
A copy camera took of the original.
The film was then developed producing a negative in order 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.
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".
Chester Carlson, an American physicist, came up with the "dry writing" invention that changed the world. He found that there were never enough copies of patents around. He worked hard to reproduce papers without rewriting them. Although his wife left him for he did not spend much time with her during his invention, she probably regretted her decision later after his millions multiplied.
Xerox made a deal with Carlson and released its first successful production line copier, the 914 copiers, in 1959.
By 1986, 7 billion copies were made daily with photocopiers.
Today the numbers could very well be 70 billion copies a day worldwide.