laser printer definition
<printer> A non-impact high-resolution printer which uses a
rotating disk to reflect laser beams to form an electrostatic
image on a selenium imaging drum. The developer drum
transfers toner from the toner bin to the charged areas of the
imaging drum, which then transfers it onto the paper into
which it is fused by heat. Toner is dry ink powder, generally
a plastic heat-sensitive polymer.
Print resolution currently (2001) ranges between 300 and 2400
dots per inch (DPI). Laser printers using chemical
photoreproduction techniques can produce resolutions of up to
2400 DPI.
Print speed is limited by whichever is slower - the printer
hardware (the "engine speed"), or the software rendering
process that converts the data to be printed into a bit map.
The print speed may exceed 21,000 lines per minute, though
printing speed is more often given in pages per minute. If a
laser printer is rated at 12 pages per minute (PPM), this
figure would be true only if the printer is printing the same
data on each of the twelve pages, so that the bit map is
identical. This speed however, is rarely reached if each page
contains different codes, text, and graphics.
In 2001, Xerox's Phaser 1235 and 2135 (with Okidata engines)
could print up to 21 colour ppm at 1200x1200 DPI using a
single-pass process.
Colour laser printers can reach 2400 DPI easily (e.g. an HP
LaserJet 8550). Some printers with large amounts of RAM can
print at engine speed with different text pages and some of
the larger lasers intended for graphics design work can print
graphics at full engine speed.
Although there are dozens of retail brands of laser printers,
only a few original equipment manufacturers make print
engines, e.g. Canon, Ricoh, Toshiba, and Xerox.
(2002-01-06)
Nearby terms:
larval stage « lase « laser « laser printer » Lasherism » last call optimisation » last-in first-out
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