Carlson, Chester Floyd

SUBJECT AREA: Photography, film and optics

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b. 8 July 1906 Seattle, Washington, USA

d. 19 September 1968 New York, USA

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American inventor of xerography

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Carlson studied physics at the California Institute of Technology and in 1930 he took a research position at Bell Telephone Laboratories, but soon transferred to their patent department. To equip himself in this field, Carlson studied law, and in 1934 he became a patent attorney at P.R.Mallory \& Co., makers of electrical apparatus. He was struck by the difficulty in obtaining copies of documents and drawings; indeed, while still at school, he had encountered printing problems in trying to produce a newsletter for amateur chemists. He began experimenting with various light-sensitive substances, and by 1937 he had conceived the basic principles of xerography ("dry writing"), using the property of certain substances of losing an electrostatic charge when light impinges on them. His work for Mallory brought him into contact with the Battelle Memorial Institute, the world's largest non-profit research organization; their subsidiary, set up to develop promising ideas, took up Carlson's invention. Carlson received his first US patent for the process in 1940, with two more in 1942, and he assigned to Battelle exclusive patent rights in return for a share of any future proceeds. It was at Battelle that selenium was substituted as the light-sensitive material.

In 1946 the Haloid Company of Rochester, manufacturers of photographic materials and photocopying equipment, heard of the Xerox copier and, seeing it as a possible addition to their products, took out a licence to develop it commercially. The first Xerox Copier was tested during 1949 and put on the market the following year. The process soon began to displace older methods, such as Photostat, but its full impact on the public came in 1959 with the advent of the Xerox 914 Copier. It is fair to apply the overworked word "revolution" to the change in copying methods initiated by Carlson. He became a multimillionaire from his royalties and stock holding, and in his last years he was able to indulge in philanthropic activities.

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Further Reading

Obituary, 1968, New York Times, 20 September.

R.M.Schaffert, 1954, "Developments in xerography", Penrose Annual.

J.Jewkes, 1969, The Sources of Invention, 2nd edn, London: Macmillan, pp. 405–8.

LRD