| A small, much-used Xerox copier in a high school library.
Photocopying is a process which makes paper copies of documents and other visual images quickly and cheaply. The prevalence of its use is one of the factors that prevented the development of the paperless office heralded early in the digital revolution.
It was introduced by Xerox in the 1960s, and over the following 20 years it gradually replaced copies made by carbon paper, mimeograph machines and other duplicating machines.
Photocopying is widely used in business, education, and government. There have been many predictions that photocopiers will eventually become moot as information workers continue to increase their digital document creation and distribution, and rely less on distributing actual pieces of paper. However, photocopiers are undeniably more convenient than computers for the very common task of creating a copy of an humble piece of paper.
James Watt invented the letter copying machine, forerunner of the digital photocopier in Birmingham, England in the 1800's. Chester Carlson, the inventor of photocopying, was originally a patent attorney and part time researcher and inventor. His job at the patent office in New York required him to make a large number of copies of important papers. Carlson who was arthritic, found this a painful and tedious process. This prompted him to conduct experiments in the area of photoconductivity, through which multiple copies could be made with minimal effort. Carlson experimented with "electrophotography" in his kitchen and in 1938, applied for a patent for the process. He made the first "photocopy" using a zinc plate covered with sulfur. The word "10-22-38 Astoria" were written on a microscope slide, which was placed on top of more sulfur and under a bright light. After the slide was removed, a mirror image of the words remained. Carlson tried to sell his invention to some companies, but because the process was still underdeveloped he failed. At the time multiple copies were made using carbon paper or duplicating machines, and people did not feel any dire need for an electronic machine. Between 1939 and 1944, Carlson was turned down by over 20 companies including IBM and GE, both of which did not believe that there was a significant market for copiers.
In 1944, the Battelle Memorial Institute, a non-profit organisation in Columbus, Ohio, contracted with Carlson to refine his new process. Over the next five years, the institute conducted experiments to improve the process of electrophotography. In 1947 Haloid (a small New York based organisation manufacturing and selling photographic paper at that time) approached Battelle to obtain a license to develop and market a copying machine based on this technology.
Haloid felt that the word "electrophotography" was too complicated and did not have good recall value. After consulting a professor of classical language at Ohio State University, Haloid and Carlson changed the name of the process to "Xerography", derived from Greek words which meant "dry writing". Haloid decided to call the new copier machines "Xerox" and in 1948, the word Xerox was trademarked.
In the early 1950s, RCA (Radio Corporation of America) introduced a variation on the process called Electrofax where images are formed directly on specially coated paper and rendered with a toner dispersed in a liquid.
In 1949, the Xerox introduced the first xerographic copier called model:A. Xerox became so successful that photocopying came to be popularly known as "Xeroxing", a situation that Xerox has very actively fought in order to prevent "xerox" from becoming a genericized trademark. "Xerox" has been found in some dictionaries as the synonym of photocopying, leading to letters and ads from the Xerox corporation asking that the entries be modified, and that people not use the term "Xerox" in this way.
Advances in technology developed the process of electrostatic copying technology where a high contrast electrostatic image copy is created on a drum and then a fusible plastic powder (called toner) is transferred to regular paper, heated and then fused into the paper similar to the technology used in laser printers. Advances allowed for color photocopies and the area of xerox art developed in the 1970s and 1980s.
Some devices sold as photocopiers have replaced the drum-based process with inkjet or transfer film technology.
Throughout the 1990s, the direct optical transfer used in photocopiers was gradually phased out. In recent years, photocopiers have adopted digital technology, with the copier effectively consisting of an integrated scanner and laser printer. This design has several advantages, such as automatic image quality enhancement and the ability to "build jobs" or scan page images independently of the process of printing them.
Coloured toner became available in the 1950s, though full colour copiers were not commercially available until 3M released the Color-in-Color copier in 1968, which used a dye sublimation process rather than the normal electrostatic technology. The first electrostatic colour copier was released by Canon? in 1973.
Color photocopying has been of concern to governments in that it makes counterfeiting currency much simpler. Some countries have introduced anti-counterfeiting technologies into their currency specifically to make it harder to use a color photocopier to counterfeit. These technologies include watermarks, microprinting, tiny security strips made of plastic or some other material, and ink that appears to change color as the currency is tilted at an angle. Some photocopying machines contain special software that will prevent the copying of currency that contains a special pattern.
The photocopying of copyright-protected material (e.g. books or scientific papers) is subject to restrictions in most countries; however it is common practice, especially by students, as the cost of purchasing a book for the sake of one article or a few pages may be excessive. In fact the principle of fair use (in the United States) or fair dealing (in other Berne Convention countries) allow this type of copying for research purposes.
In some countries, such as Canada, some universities pay royalties from each photocopy made at university copy machines and copy centers to copyright collectives out of the revenues from the photocopying and these collectives distribute these funds to various scholarly publication publishers.
See also: List of duplicating processes, multifunctional copier.