Chester Carlson - The Invention of Electrophotography

The Invention of Electrophotography

Further information: Xerography There was a gap of some years, but by 1935 I was more or less settled. I had my job, but I didn't think I was getting ahead very fast. I was just living from hand to mouth, you might say, and I had just got married. It was kind of a hard struggle. So I thought the possibility of making an invention might kill two birds with one stone; it would be a chance to do the world some good and also a chance to do myself some good. —Chester Carlson, to A. Dinsdale

In 1936, Carlson began to study law at night at New York Law School, receiving his LL.B. degree in 1939. He studied at the New York Public Library, copying longhand from law books there because he could not afford to buy them. The pains induced by this laborious copying hardened his resolve to find a way to build a true copying machine. He began supplementing his law studies with trips to the Public Library's science and technology department. It was there that he was inspired by a brief article, written by Hungarian physicist Pál Selényi in an obscure German scientific journal, that showed him a way to obtain his dream machine.

Carlson's early experiments, conducted in his apartment kitchen, were smoky, smelly, and occasionally explosive. In one set of experiments, he was melting pure crystalline sulfur (a photoconductor) onto a plate of zinc by moving it just so over the flame of his kitchen stove. This often resulted in a sulfur fire, filling the building with the smell of rotten eggs. In another experiment, the chemicals he was working with caught fire, and he and his wife were hard-pressed to extinguish the flames.

During this period, he developed arthritis of the spine, like his father. He pressed on with his experiments, however, in addition to his law school studies and his regular job.

Having learned about the value of patents in his early career as a patent clerk and attorney, Carlson patented his developments every step along the way. He filed his first preliminary patent application on October 18, 1937.

By the fall of 1938, Carlson's wife had convinced him that his experiments needed to be conducted elsewhere. He rented a room on the second floor of a house owned by his mother-in-law at 32-05 37th Street in Astoria, Queens. He hired an assistant, Otto Kornei, an out-of-work Austrian physicist.

Carlson knew that several major corporations were researching ways of copying paper. The Haloid Company had the Photostat, which it licensed to Eastman Kodak, the photography giant. However, these companies were researching along photographic lines, and their solutions required special chemicals and papers. The Photostat, for instance, was essentially a photograph of the document being copied.