LEDprinters

LEDprinters, often written as LED printers, are a class of electrophotographic printers that use an array of light-emitting diodes as the exposure source instead of a laser diode. The LED array writes the latent image on a photoconductive drum or belt, which is subsequently developed with toner.

The charged surface is exposed by the LEDs to create an electrostatic image; toner is attracted to the latent image, transferred to paper, and fused by heat. The process repeats for each page as the media advances.

Many LEDprinters employ either a full-width LED array that exposes the entire page in one pass or a line-mode array that writes one line at a time as the sheet moves. This differs from laser printers, which use a rotating polygon mirror to scan a laser beam.

Advantages include fewer moving parts, reduced mechanical wear, and potentially higher reliability. LEDs have long lifetimes, and LED-based exposure can be energy efficient and produce compact, quiet engines.

Disadvantages include higher upfront cost for color models and the need for a wide LED write head to cover standard page widths. Some devices may exhibit non-uniform exposure if the LED array ages unevenly, though modern units mitigate.

LED printing technology became commercially available in the late 20th century as an alternative to laser xerography and is used in various office and commercial printers. See also laser printer and electrophotographic printing.