Desktop and workgroup printers for business employ a variety of technologies, each with its own tradeoffs for cost, speed and quality. An organization that prints its own manuals, financial reports and other multipage documents needs a faster printer than a company that produces only an occasional invoice. As of the date of publication, laser printers take top honors for speed; dot-matrix models have similar speeds but lower quality, and inkjet models are significantly slower.
Laser and LED
Laser and Light-Emitting Diode (LED) printers share technology with copy machines, printing a whole page at a time. Inside the printer, a laser beam or array of LEDs scans the surface of a light-sensitive metal drum, forming patterns of static electricity. Toner powder sticks to the areas of static charge; when the mechanism presses paper against the drum, the toner binds to the sheet, forming a printed page. The speed of desktop laser printers ranges from 4 to more than 50 pages per minute; commercial models produce at rates up to 1,000 ppm.
Thermal
Thermal printers are specialty devices used in cash registers, bar-code systems, label makers and calculators. In a thermal printer, an electronic system controls an array of heating elements that produce tiny hot spots on specially-treated paper. Above a certain temperature, the paper turns black. The printing process is rugged, economical and easy to maintain, as it needs no ink. Some of the fastest examples print at a rate of 300 millimeters per second, or an equivalent of 60 pages per minute. These types of printers are not used for general-purpose word-processing or report documents.
Inkjet
An inkjet printer produces relatively low volumes of high-quality documents. It prints by spraying microscopic droplets of ink from a cartridge directly onto a page; the cartridge moves back and forth across the paper, gradually rendering the document a line at a time. Inkjet printer speeds generally run from 1 to 20 ppm; the better the quality of printing, the fewer ppm.
Dot Matrix
Although largely replaced by newer inkjet and laser technologies, dot-matrix printers continue to find uses because of their reliability, low operating costs and ability to print multipart forms. A dot-matrix printer is an impact design, forming characters on the page by striking an inked ribbon with thin wire pins. Depending on the model, their speed ranges between 200 and 1,120 characters per second, or about 12 to 60 pages per minute in draft mode. A high-quality mode runs half to a third of the maximum speed; the print mechanism makes two or three passes per line of text, filling the shapes of each character.