A photocopier (also called copier or copy machine, and formerly Xerox machine, the generic trademark) is a machine that makes copies of documents and other visual images onto paper or plastic film quickly and cheaply. Most modern photocopiers use a technology called xerography, a dry process that uses electrostatic charges on a light-sensitive photoreceptor to first attract and then transfer toner particles (a powder) onto paper in the form of an image. The toner is then fused onto the paper using heat, pressure, or a combination of both.
Prestressed concrete is a form of concrete used in construction. It is substantially "prestressed" (compressed) during production, in a manner that strengthens it against tensile forces which will exist when in service. This compression is produced by the tensioning of high-strength "tendons" located within or adjacent to the concrete and is done to improve the performance of the concrete in service. Tendons may consist of single wires, multi-wire strands or threaded bars that are most commonly made from high-tensile steels, carbon fiber or aramid fiber.
Duplicating machines were the predecessors of modern document-reproduction technology. They have now been replaced by digital duplicators, s, laser printers and photocopiers, but for many years they were the primary means of reproducing documents for limited-run distribution. The duplicator was pioneered by Thomas Edison and David Gestetner, with Gestetner dominating the market up until the late 1990s. Like the typewriter, these machines were products of the second phase of the Industrial Revolution which started near the end of the 19th century (also called the Second Industrial Revolution).
An electrofax was a type of fax. It involved electrostatic printer and copier technology, where an image was formed directly on the paper, instead of first on a drum, then transferred to paper, as it would be in xerography. It was used in the United States from the 1950s through the 1980s. The paper used in this process was coated with a zinc oxide powder, adhered with a resin, to make it able to hold an electrostatic charge, and absorb toner, to form an image and allow the evaporation of toner dispersants.
Xerox Holdings Corporation (ˈzɪərɒks, ; also known simply as Xerox) is an American corporation that sells print and digital document products and services in more than 160 countries. Xerox is headquartered in Norwalk, Connecticut (having moved from Stamford, Connecticut, in October 2007), though it is incorporated in New York with its largest population of employees based around Rochester, New York, the area in which the company was founded. The company purchased Affiliated Computer Services for $6.
