In computing, a printer is a peripheral which produces a representation of an electronic document on physical media such as paper or transparency film. Many printers are local peripherals connected directly to a nearby personal computer. Individual printers are often designed to support both local and network connected users at the same time. Some printers can print documents stored on memory cards or from digital cameras and scanners.Multifunction printers (MFPs) include a scanner and can copy paper documents or send a fax; these are also called multi-function devices (MFD), or all-in-one (AIO) printers. Most MFPs include printing, scanning, and copying among their many features.
Consumer and some commercial printers are designed for low-volume, short-turnaroundprint jobs; requiring virtually no setup time to achieve a hard copy of a given document. However, printers are generally slow devices (30 pages per minute is considered fast, and many inexpensive consumer printers are far slower than that), and the cost per page is actually relatively high. However, this is offset by the on-demand convenience and project management costs being more controllable compared to an out-sourced solution. Theprinting press remains the machine of choice for high-volume, professional publishing. However, as printers have improved in quality and performance, many jobs which used to be done by professional print shops are now done by users on local printers; see desktop publishing. Local printers are also increasingly taking over the process of photofinishing as digital photo printers become commonplace.
The world's first computer printer was a 19th-century mechanically driven apparatus invented by Charles Babbage for his difference engine.
A virtual printer is a piece of computer software whose user interface and API resembles that of a printer driver, but which is not connected with a physical computer printer.
Technology
Printers can be classified by the printer technology they employ, with many techniques being available as commercial products. The choice of print technology has a great effect on the cost of the printer and cost of operation, speed, quality and permanence of documents, and noise. Some printer technologies don't work with certain types of physical media, such ascarbon paper or transparencies.
A second aspect of printer technology that is often forgotten is resistance to alteration: liquidink, such as from an inkjet head or fabric ribbon, becomes absorbed by the paper fibers, so documents printed with liquid ink are more difficult to alter than documents printed with toner or solid inks, which do not penetrate below the paper surface.
Cheques can be printed with liquid ink or on special cheque paper with toner anchorage so that alterations may be detected. The machine-readable lower portion of a cheque must be printed using MICR toner or ink. Banks and other clearing houses employ automation equipment that relies on the magnetic flux from these specially printed characters to function properly.
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