Printer (computing)

A printer is a peripheral machine which makes a durable representation of graphics or text, usually on paper. While most output is human-readable, bar code printers are an example of an expanded use for printers. Different types of printers include 3D printers, inkjet printers, laser printers, and thermal printers.

History

The first computer printer designed was a mechanically driven apparatus by Charles Babbage for his difference engine in the 19th century; however, his mechanical printer design was not built until 2000. He also had plans for a curve plotter, which would have been the first computer graphics printer if it was built.
The first patented printing mechanism for applying a marking medium to a recording medium or more particularly an electrostatic inking apparatus and a method for electrostatically depositing ink on controlled areas of a receiving medium, was in 1962 by C. R. Winston, Teletype Corporation, using continuous inkjet printing.
The ink was a red stamp-pad ink manufactured by Phillips Process Company of Rochester, NY under the name Clear Print. This patent led to the Teletype Inktronic Printer product delivered to customers in late 1966.
The first compact, lightweight digital printer was the EP-101, invented by Japanese company Epson and released in 1968, according to Epson.
The first commercial printers generally used mechanisms from electric typewriters and Teletype machines. The demand for higher speed led to the development of new systems specifically for computer use. In the 1980s there were daisy wheel systems similar to typewriters, line printers that produced similar output but at much higher speed, and dot-matrix systems that could mix text and graphics but produced relatively low-quality output. The plotter was used for those requiring high-quality line art like blueprints.
The introduction of the low-cost laser printer in 1984, with the first HP LaserJet, and the addition of PostScript in next year's Apple LaserWriter set off a revolution in printing known as desktop publishing. Laser printers using PostScript mixed text and graphics, like dot-matrix printers, but at quality levels formerly available only from commercial typesetting systems. By 1990, most simple printing tasks like fliers and brochures were now created on personal computers and then laser printed; expensive offset printing systems were being dumped as scrap. The HP Deskjet of 1988 offered the same advantages as a laser printer in terms of flexibility, but produced somewhat lower-quality output from much less-expensive mechanisms. Inkjet systems rapidly displaced dot-matrix and daisy-wheel printers from the market. By the 2000s, high-quality printers of this sort had fallen under the $100 price point and became commonplace.
The rapid improvement of internet email through the 1990s and into the 2000s has largely displaced the need for printing as a means of moving documents, and a wide variety of reliable storage systems means that a "physical backup" is of little benefit today.
Starting around 2010, 3D printing became an area of intense interest, allowing the creation of physical objects with the same sort of effort as an early laser printer required to produce a brochure. As of the 2020s, 3D printing has become a widespread hobby due to the abundance of cheap 3D printer kits, with the most common process being Fused deposition modeling.

Types

;Personal printers: Personal printers are mainly designed to support individual users, and may be connected to only a single computer. These printers are designed for low-volume, short-turnaround print jobs, requiring minimal setup time to produce a hard copy of a given document. They are generally slow devices ranging from 6 to around 25 pages per minute, and the cost per page is relatively high. However, this is offset by the on-demand convenience. Some printers can print documents stored on memory cards or from digital cameras and scanners.
;Networked printers: Networked, workgroup or shared printers are designed for high-volume, high-speed printing. They are usually shared by many users on a network and can print at speeds of 45 to around 100 ppm. The Xerox 9700 could achieve 120 ppm.
;Card printers: A card printer or ID-card printer is used for printing plastic cards, including ID cards. These can now be customised with important features such as holographic overlays, HoloKotes and watermarks. This is either a direct to card printer or a retransfer printer.
;Virtual printer: 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. A virtual printer can be used to create a file which is an image of the data which would be printed, for archival purposes or as input to another program, for example to create a PDF or to transmit to another system or user.
;Barcode printer: A barcode printer is a computer peripheral for printing barcode labels or tags that can be attached to, or printed directly on, physical objects. Barcode printers are commonly used to label cartons before shipment, or to label retail items with UPCs or EANs.
;3D printer: A 3D printer is a device for making a three-dimensional object from a 3D model or other electronic data source through additive processes in which successive layers of material are laid down under computer control. It is called a printer by analogy with an inkjet printer which produces a two-dimensional document by a similar process of depositing a layer of ink on paper.

Technology

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 do not work with certain types of physical media, such as carbon paper or transparencies.
A second aspect of printer technology that is often forgotten is resistance to alteration: liquid ink, 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.

Modern print technology

The following printing technologies are routinely found in modern printers:

Laser printers and other toner-based printers

A laser printer rapidly produces high quality text and graphics. As with digital photocopiers and multifunction printers, laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor.
Another toner-based printer is the LED printer which uses an array of LEDs instead of a laser to cause toner adhesion to the print drum.

Liquid inkjet printers

operate by propelling variably sized droplets of liquid ink onto almost any sized page. They are the most common type of computer printer used by consumers.

Solid ink printers

printers, also known as phase-change ink or hot-melt ink printers, are a type of thermal transfer printer, graphics sheet printer or 3D printer. They use solid sticks, crayons, pearls or granular ink materials. Common inks are CMYK-colored ink, similar in consistency to candle wax, which are melted and fed into a piezo crystal operated print-head. A Thermal transfer printhead jets the liquid ink on a rotating, oil coated drum. The paper then passes over the print drum, at which time the image is immediately transferred, or transfixed, to the page. Solid ink printers are most commonly used as color office printers and are excellent at printing on transparencies and other non-porous media. Solid ink is also called phase-change or hot-melt ink and was first used by Data Products and Howtek, Inc., in 1984. Solid ink printers can produce excellent results with text and images. Some solid ink printers have evolved to print 3D models, for example, Visual Impact Corporation of Windham, NH was started by retired Howtek employee, Richard Helinski whose 3D patents US4721635 and then US5136515 was licensed to Sanders Prototype, Inc., later named Solidscape, Inc. Acquisition and operating costs are similar to laser printers. Drawbacks of the technology include high energy consumption and long warm-up times from a cold state. Also, some users complain that the resulting prints are difficult to write on, as the wax tends to repel inks from pens, and are difficult to feed through automatic document feeders, but these traits have been significantly reduced in later models. This type of thermal transfer printer is only available from one manufacturer, Xerox, manufactured as part of their Xerox Phaser office printer line. Previously, solid ink printers were manufactured by Tektronix, but Tektronix sold the printing business to Xerox in 2001.

Dye-sublimation printers

A dye-sublimation printer is a printer that employs a printing process that uses heat to transfer dye to a medium such as a plastic card, paper, or canvas. The process is usually to lay one color at a time using a ribbon that has color panels. Dye-sub printers are intended primarily for high-quality color applications, including color photography; and are less well-suited for text. While once the province of high-end print shops, dye-sublimation printers are now increasingly used as dedicated consumer photo printers.

Thermal printers

work by selectively heating regions of special heat-sensitive paper. Monochrome thermal printers are used in cash registers, ATMs, gasoline dispensers and some older inexpensive fax machines. Colors can be achieved with special papers and different temperatures and heating rates for different colors; these colored sheets are not required in black-and-white output. One example is Zink.