011 – Sincerest form of flattery – 1938

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Someday, I’m going to make a big invention. Chester Carlson aged 12

Xerography was invented by Chester Carlson in late 1938.

While working in a patent office he came to appreciate that there were never enough copies of a patent specification.  Further copies using a photocopier were expensive; having them re-typed and checked was costly and time-consuming.

Carlson wanted a machine that could provide low cost copies in seconds.  He researched the copying methods that existed and dismissed the idea of photography because he judged that larger corporations were already applying big teams and deep pockets on this approach.

He looked instead at photoconductivity and electrostatics; he combined the techniques in electro-photography.  He named the process ‘xerography’, based on the Greek xeros meaning dry and graphos meaning writing – emphasising that it was a dry system with no noxious chemicals or fluids.

Using a sulphur-coated zinc plate his assistant Otto Kornei wrote the date and location ’10-22-38 ASTORIA’ on a glass microscope slide.  They then minimised ambient light and rubbed the plate with a handkerchief to create an electrostatic charge.  The slide was laid on a plate and put under bright incandescent lamplight for a few seconds.  This neutralised the charge wherever there was no image.

They then sprinkled the plate’s surface with lycopodium powder, which was usually used for camera flash.  Gently blowing away the powder revealed a perfect copy of Otto’s writing which had adhered to the plate by the electrostatic charge behind the projected image.

In October 1942 Carlson was granted a patent for xerography but seventeen years passed before his concept was in production. 

He approached big corporates of the day but not one showed any interest.  IBM scoffed, ‘The world potential market for copying machines is 5000 at most.’ – perhaps unsurprising from the company that later was claimed to have forecast the world sales potential for computers at just five units.

Battelle Memorial Institute, a private, not-for-profit science and technology development company, came to his aid.

Battelle showed the Chester Carlson xerographic process to Joe Wilson who was employed in his father’s business, The Haloid Photographic Company.  The company was ailing until Wilson threw its effort into developing dry photographic copiers – the company name was later changed to Xerox.

The establishment of Xerox PARC (Palo Alto Research Center) in 1970 assembled the team that would do much to define the personal computer.  They would later inspire Apple, Microsoft and others to proceed to create the PC sector.

By the late noughties the market, no longer exclusively controlled by Xerox of course, had grown into a document management industry of more than $112billionn and it was estimated that more than 4 trillion pages had been reproduced by xerography. Carlson died in 1968, but not before he donated $100m+ to charity.

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