Making Copies

At first, nobody bought Chester Carlson’s strange idea. But trillions of documents later, his invention is the biggest thing in printing since Gutenburg

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By the time Chester entered high school, he was his family’s principle provider. Still, he managed to make good grades, especially in science, and began to think seriously about how he might use his talents. He considered gold prospecting, publishing and other occupations before deciding his best chance would be to invent something valuable.

At 15, Chester began jotting down ideas for inventions and making other notes in a pocket diary, a practice he maintained for the rest of his life. He sketched concepts for a rotating billboard, a machine for cleaning shoes and a trick safety pin (which could be made to look as though it had pierced a finger). He was fascinated by printing and the graphic arts. When he was 10, his favorite possession was a toy typewriter. Later, he worked in a print shop and published a magazine, the Amateur Chemists’ Press, for scienceminded classmates. “I was impressed with the tremendous amount of labor involved in getting something into print,” he recalled in a 1965 interview with Joseph J. Ermenc, a Dartmouth professor. “That set me to thinking about easier ways to do that, and I got to thinking about duplicating methods.” During his junior year in high school, his mother—his one source of happiness, encouragement, stability and love— died of tuberculosis, at 53. Her death devastated him; 25 years later, he was almost physically unable to speak of it. “The worst thing that ever happened to me,” he recalled. “I so wanted to be able to give her a few things in life.” By the time he graduated from high school, he and Olof had been reduced to living in a former chicken coop, whose single room had a bare concrete floor. Chester slept outdoors, partly to lessen his own chance of contracting the disease that had killed his mother, on a narrow strip of packed earth between the building and a board fence that ran along the alley, in a sleeping bag that he himself had made.

Carlson worked his way through three years at a nearby junior college, then transferred to Cal Tech, where he majored in physics and supported himself and his father by mowing lawns, doing odd jobs and working at a cement mill. (His father, with whom he shared a small apartment, in Pasadena, pitched in by doing the cooking.) He graduated in 1930 and was hired by Bell Labs, in New York City, as a research engineer. After a year, he transferred to the company’s patent department, believing the skills he would learn there might be useful to him when he became an inventor.

In his notebooks during the 1930s, Carlson recorded more than 400 ideas for products, among them a raincoat with gutters to channel water away from trouser legs; a toothbrush with replaceable bristles; a see-through toothpaste tube, made of cellophane; a perforated-plastic filter tip for cigarettes. In 1934, he married Elsa von Mallen, who had given him her telephone number after dancing with him to Duke Ellington records at a party at the YWCA. The marriage was troubled almost from the beginning. “I don’t know what to do or say—he’s so much smarter,” she said shortly before they divorced, in 1945. Partly to get out of the house, Carlson enrolled in night classes at New YorkLawSchool in 1936. He did most of his studying at the New York Public Library, where he copied by hand long passages from law books that he couldn’t afford to buy. His copying gave him writer’s cramp and made him think again about the desirability of a device that, unlike carbon paper, could be used to reproduce documents that already existed.

“I recognized quite early that if conventional photography would have worked for an office copier it would have been done before by the big companies in the photographic field who certainly would have explored that possibility pretty thoroughly,” he told Ermenc. “So I deliberately turned away from the conventional photographic processes and started searching in the library for information about all the different ways in which light will affect matter. I soon came upon photoelectricity and photoconductivity.”

Photoelectricity is such a complex phenomenon that it took Albert Einstein to explain it, in 1905; he was awarded the Nobel Prize in 1921 for having done so. (Incidentally, Einstein, like Carlson, was a physicist who worked in a patent office.) A photoconductive material is one whose ability to conduct electricity increases when light shines on it. Carlson reasoned that he might be able to make a copying machine based on photoconductivity if he could find a material that acted as a conductor when it was illuminated and as an insulator when it was not. His plan was to apply a thin layer of the material to an electrically grounded metal plate. Then, in the dark, he would apply a uniform static electric charge to the entire coated surface. Next, he would project an image of a printed page onto the charged surface, thereby causing the charge to drain away to ground from the illuminated areas (the ones corresponding to the reflective white background of the page) while allowing the charge to persist in areas that remained dark (the ones corresponding to the black ink). Finally, he would dust the entire surface with an oppositely charged powdered toner, which would adhere only to the places where charges remained, thereby forming a visible (and reversed) image of the original page. The powder could then be transferred to a sheet of paper and fused to it: a copy.

This idea would become the basis of xerography. Every xerographic office copier and laser printer contains a photo- conductive surface, which is known as the photoreceptor. (In a laser printer, the light that shines on the photoreceptor is a digitally controlled laser beam.) Carlson applied for his first patent on October 18, 1937, and began conducting crude experiments. He had learned from his reading that sulfur had the photoconductive properties he was looking for, so he bought some at a chemical supply store and attempted to liquefy it by heating it over a burner on the stove in the kitchen of his apartment, in Queens. In nearly a year of experimentation, he accomplished little beyond setting his sulfur on fire, filling his apartment building with the smell of rotten eggs and angering his wife.

In 1938, he rented a laboratory and hired an assistant, an unemployed physicist named Otto Kornei, who had recently emigrated from Austria. Carlson’s laboratory was really just the back room of a beauty parlor—it had previously served as a janitor’s closet—but it had running water and a gas connection, and Kornei soon succeeded in applying a thin film of liquefied sulfur to zinc plates the size of business cards.

Working with Carlson one day soon afterward, he wrote the date and place—10.-22.-38 ASTORIA—on a glass microscope slide, turned out the lights and rubbed a sulfur-coated plate with his handkerchief to give it a static electric charge. As Carlson watched, Kornei placed the slide facedown against the plate and turned on a bright flood lamp for several seconds. He turned off the lamp, removed the slide and dusted the plate with powder. “The letters came out clearly,” Carlson wrote later. Carlson pressed a piece of wax paper against the image so that most of the powder stuck to it. He was now holding the world’s first xerographic copy. (That historic copy is in the Smithsonian’s collection.) He gazed at the paper for a long time and held it up to the window. Then he took his assistant to lunch.

Kornei, unlike his boss, was unimpressed, and soon took a job at an electronics company in Cleveland. Carlson continued alone and spent six years unsuccessfully trying to interest companies in developing and manufacturing the machine he had envisioned. In 1944, a chance conversation led him to the Battelle Memorial Institute, a private, nonprofit research-and-development organization in Columbus, Ohio. He performed his standard demonstration for a halfdozen of Battelle’s scientists and engineers, then braced himself for the throat-clearing and paper-rearranging that was the usual response to his presentations. But a Battelle engineer named Russell Dayton held up the scrap of wax paper and said to his colleagues, “However crude this may seem, this is the first time any of you have seen a reproduction made without any chemical reaction and [with] a dry process.” Battelle agreed to invest.


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