A printer produces a hard copy of readable text and/or graphics usually
on physical print media such as paper. The majority of printers are
computer peripherals that are attached to a computer (document source) by a
printer cable. There are also network printers that have built-in network
interfaces that are typically wireless and are used as a hardcopy device for any
user on the network.
Many modern printers can directly interface to electronic media such as memory sticks or memory cards, or to image capture devices such as digital cameras, scanners; some printers are combined with a scanners and/or fax machines in a single unit.
A printer which is combined with a scanners can essentially function as a photocopier.
The computer printer was designed for print jobs that are low in volume with
quick-turnaround times. There is practically no set-up time involved in
producing a hard copy. The down side to printers is that they are
considered slow in producing the hard copies and the cost-per-page is relatively
high. In contrast, the printing press was designed for high volume jobs with the
cost-per-page a fraction of that of printers.
For professional publishing, the printing press would be the one of choice.
However, computer printers are constantly improving with regards to quality and
performance contributing to an increase of professional prints jobs being done
by local printers as opposed to professional print shops; see desktop publishing.
The world's first computer printer was a 19th-century mechanically driven apparatus invented by Charles Babbage for his Difference Engine.