What Is a Printer?

A printer is a device that takes digital data and makes it visible on paper or other media. It can be connected directly to a computer or indirectly via a network.

It prints text and graphics on paper based on a digital data file sent from a host computer, but can also serve an expanded role as an image scanner and copy machine. Modern printers are mainly of the inkjet, laser and thermal types and are capable of monochrome, color or grayscale printing. A number of variants exist, such as multifunction devices that combine various functions into a single unit.

Printing is a key part of paper-based publishing, transaction printing (such as in banks and supermarkets) and commercial typesetting. Johann Gutenberg of Mainz, Germany developed European movable-type printing in 1440, basing his work on earlier wine press designs.

Early “journeyman” printers were free to roam Europe with their tools and take on any printing job that came their way. This allowed them to produce publications of greater variety than were possible with the limited type sets available at master printers’ shops. By 1500 – 1700, however, the role of the journeyman had largely been replaced by the bookseller publisher, who could negotiate fees with publishers and thus control publication costs.

Inkjet printers use an array of tiny nozzles to spray ink or toner on the paper in precise patterns according to the digital data being printed. Laser and thermal printers use an image on a drum which is transferred to the paper by heat or light. In monochrome thermal printers, each pixel in the raster is created by selectively heating certain regions of the paper to create black or white.