Colour
Toner Cartridges and Colour Laser Printing
Colour
Laser Printers
Initially, most commercial laser printers were limited to
monochrome printing (black writing on white paper). But
now, there are lots of colour laser printers on the market.
Essentially, colour laser printers work the same way as
monochrome printers, except they go through the entire printing
process four times -- one pass each for cyan (blue), magenta
(red), yellow and black. By combining these four colours
of toner in varying proportions, you can generate the full
spectrum of colour.
There
are several different ways of doing this. Some models have
four toner and developer units on a rotating wheel. The
printer lays down the electrostatic image for one colour
and puts that toner unit into position. It then applies
this colour to the paper and goes through the process again
for the next colour . Some printers add all four colours
to a plate before placing the image on paper.
Some
more expensive printers actually have a complete printer
unit -- a laser assembly, a drum and a toner system -- for
each colour . The paper simply moves past the different
drum heads, collecting all the colours in a sort of assembly
line.
So
why get a laser printer rather than a cheaper inkjet printer?
The main advantages of laser printers are speed, precision
and economy. A laser can move very quickly, so it can "write"
with much greater speed than an ink jet. And because the laser
beam has an unvarying diameter, it can draw more precisely,
without spilling any excess ink.
Laser printers tend to be more expensive than inkjet printers,
but it doesn't cost as much to keep them running -- toner
powder is cheap and lasts a long time, while you can use up
expensive ink cartridges very quickly. This is why offices
typically use a laser printer as their "work horse,"
their machine for printing long text documents. In most models,
this mechanical efficiency is complemented by advanced processing
efficiency. A typical laser-printer controller can serve everybody
in a small office.
When
they were first introduced, laser printers were too expensive
to use as a personal printer. Since that time, however,
laser printers have gotten much more affordable. Now you
can pick up a basic model for just a little bit more than
a nice inkjet printer.
As
technology advances, laser-printer prices should continue
to drop, while performance improves. We'll also see a number
of innovative design variations, and possibly brand-new
applications of electrostatic printing. Many inventors believe
we've only scratched the surface of what we can do with
simple static electricity! (Thanks to How
Stuff Works)
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