Photocopying is a process which makes paper copies of documents and other visual images quickly and cheaply. The prevalance 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 mimeograph machines and other duplicating machines. Sometimes copies are called xerox copies, although the Xerox corporation actively discourages this usage so as not to lose trademark protection on the term. Originally it was purely photographic, and the copies were negatives transferred directly to photo paper and developed with the use of photographic chemicals in the photocopy machine.
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. More recent technology includes the use of ink jet or bubble jet technology to make color copies and transfer ribbon technology (often found multi-function 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 a humble piece of paper.
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.
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.