A computer-controlled array of ink nozzles can produce images on a moving sheet or web of paper.

Today, simple ink-jet printers are the mainstay of domestic computer systems but they are also used routinely to print variable information such as the expiry dates on food packages or address labels on direct mail pieces, and are sometimes installed on the end of a conventional printing press for "spot" colours.

Sophisticated colour ink-jet printers are able to produce lithographic-quality reproductions but they are relatively slow and only cost-effective for very short runs such as in the production of advertisments for shops, posters, banners or short runs of artists paintings.

A particular advantage of inkjet printing is that the process does not expose the material to heat or pressure. Accordingly it can be used on materials that could be damaged in lithographic or xerographic processes. For example, data or images can be added by inkjet printing to material produced on a lazer printer whereas reprocessing the material in another lazer printer could damage both the printer and the material.