Wednesday, March 12, 2008

Computer Printer

A computer printer, or more commonly a printer, produces a hard copy of documents stored in electronic form, usually on substantial print media such as paper or transparencies. Many printers are principally used as local computer peripherals, and are attached by a printer cable to a computer which serves as a document resource. Some printers, commonly known as network printers, have built-in network interfaces, and can serve as a hardcopy device for any user on the network. Individual printers are often designed to support both local and network connected users at the same time.

In addition, many modern printers can directly interface to electronic media such as memory sticks or memory cards, or to image detain devices such as digital cameras, scanners; some printers are combined with a scanners and/or fax machines in a single unit. Printers that include non-printing features are sometimes called Multi-Function Printers (MFP) or Multi-Function Devices (MFD).

A printer which is combined with a scanner can function as a photocopier if so designed. Most MFPs include printing, scanning, and copying among their features. Printers are designed for low-volume, short-turnaround print jobs; requiring practically 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 consumer printers are far slower than that), and the cost-per-page is relatively high.

In contrast, the printing press (which serves much the same function), is designed and optimized for high-volume print jobs such as newspaper print runs--printing presses are capable of hundreds of pages per minute or more, and have an incremental cost-per-page which is a portion of that of printers. The printing press remains the machine of choice for high-volume, proficient publishing. However, as printers have improved in quality and performance, many jobs which used to be done by proficient print shops are now done by users on local printers; see desktop publishing. The world's first computer printer was a 19th century involuntarily driven apparatus invented by Charles Babbage for his Difference Engine.