CARLSON, CHESTER F.
Chester Floyd Carlson (1906-1968) invented xerography (which means "dry writing" in Greek) in 1938. Xerography makes paper copies without using ink (hence its name). In this process, static electricity charges a lighted plate; a plastic powder (called toner) is applied to the areas of the page to remain white.
Chester F. Carlson was born in Seattle, Washington, USA. As a teenager, Carlson supported his invalid parents by publishing a chemical journal. After attending Cal Tech in physics, Carlson worked at an electronics firm. Carlson later experimented at home to find an efficient way of copying pages. He succeeded in 1938, and marketed his revolutionary device to about 20 companies before he could interest any. The Haloid Company (later called the Xerox Corporation) marketed it, and photocopying eventually became common and inexpensive.