Invented by : Chester Carlson
Invented in year : 1938
Xerography or Electrophotography is a Dry Photocopying Technique. It was invented by Physicist Chester F. Carlson, who is also known as The Father of Xerographic Printing. His invention was developed and commercialized by the Xerox Corporation. Xerography is widely used to produce high-quality text and graphic images on paper. It's based on two natural phenomena : that materials of opposite electrical charges attract and that some materials become better conductors of electricity when exposed to light. Carlson invented a six-step process to transfer an image from one surface to another using these phenomena.
First, a photoconductive surface is given a positive electrical charge. The photoconductive surface is then exposed to the image of a document. Because the illuminated sections (the non-image areas) become more conductive, the charge dissipates in the exposed areas. Negatively charged powder spread over the surface adheres through electrostatic attraction to the positively charged image areas. A piece of paper is placed over the powder image and then given a positive charge. The negatively charged powder is attracted to the paper as it is separated from the photoconductor. Finally, heat fuses the powder image to the paper, producing a copy of the original image.
History of the Invention
As a young man, Carlson worked as a patent analyser for an electrical component maker. The job required him to prepare the paperwork which was submitted to the patent office to register his company's inventions and ideas. However, the patent office required multiple copies which he had to duplicate by hand. Redrawing was a hard work and the copies took hours. To add to his woes, Carlson was near-sighted and had arthritis, which made his job even more difficult. Carlson often thought of how convenient it would be to have easily made copies of patent specification. For many months Carlson spent his evenings at the New York Public Library reading all he could about imaging processes. He decided immediately not to research in the area of conventional photography, where light is an agent for chemical change, because that phenomenon was already being exhaustively explored in research labs of large corporations.
He knew that the research laboratories of many companies were already working on chemical and thermal means of copying papers, so he began to think about different ways of doing the same thing. Months of research at the New York Public Library led him to photoconductivity, in which light can increase the electric conductivity of certain kind of materials under certain conditions.Carlson turned to the little-known field of photoconductivity, specifically the findings of Hungarian physicist Paul Selenyi, who was experimenting with electrostatic images. He learned that when light strikes a photoconductive material, the electrical conductivity of that material is increased. He began some rudimentary experiments in the kitchen of his apartment in Jackson Heights, Queens. It was here that Carlson unearthed the fundamental principles of what he called electrophotography - later to be named xerography - and defined them in a patent application filed on 18th October, 1937.
He set up a small lab in nearby Astoria and hired an unemployed young physicist, a German refugee named Otto Kornei, to help with the lab work. It was here, in a rented second-floor room above a bar, where xerography was invented in 1938. He pounded the pavement for years in a fruitless search for a company that would develop his invention into a useful product. From 1939 to 1944, he was turned down by more than twenty companies. Even the National Inventors Council dismissed his work. However if not anything he received patent #2,297,691 on October 6, 1942 for electrophotography. Finally, in 1944, Battelle Memorial Institute, a non-profit research organization, became interested, signed a royalty-sharing contract with Carlson, and began to develop the process. And in 1947, Battelle entered into an agreement with a small photo-paper company called Haloid (later to be known as Xerox), giving Haloid the right to develop a xerographic machine. On October 22, 1948, the Haloid Company made the first public announcement of xerography. They made their first sale of the Haloid Xerox Copier in 1950. The company continued to improve the concept, producing the Xerox 914 in 1959 in Jackson Heights, Queens. The 914 copier could make copies quickly at the touch of a button on plain paper.
Development in the Invention of Xerography
As early as 1955 Ricoh were emerging as a potential competitor for Xerox and developed the RiCopy 101 Diazo copier. In 1968, 3M released the Color-in-Color copier which used a dye sublimation process rather than the normal electrostatic technology. In 1973, the first electrostatic colour copier was released by Canon.
In 1969, the Laser Printer was invented at Xerox by Researcher Gary Starkweather The earliest model was based on the company’s own xerographic copiers and was modified according to the requirements of a printer.
In 1975 Ricoh had developed a prize winning copier called RiCopy DT 1200. Brands such as Minolta, Panasonic, Toshiba, Canon, Konica and of course Sharp began to produce small office copiers, which became a big challenge in completion for Xerox’s domination in the business copier market.
Role of Xerography in the Improvement Of Human Life
- Xerography made the process of documentation even more faster, thereby saving lots of effort and money.
- Xerography became the foundation stone of a gigantic worldwide copying industry, including Xerox and other corporations which made and marketed copiers and duplicators, thereby earning billions.
- Photocopying started to be widely used in business, education, and government.
