|
It's easy to take your photocopier for granted:
you insert a sheet of paper, press a button, and the machine spits
out a copy. For most offices, large or small, photocopiers are as
essential to daily life as computers and printers. But have you
ever wondered what goes on inside your copier?
Reflecting the image
When you press the "Start" button on your copier, a bright light
travels across your document. That light, which comes from an ordinary
fluorescent or incandescent bulb, bounces off your page, and causes
the page's image to be reflected through a lens onto the photoreceptor
drum below. By adjusting the location of the lens -- its distance
from the original and from the drum -- you can cause the reflected
image to be a reduced or enlarged version of the original.
Charging the drum assembly
The photoreceptor drum functions very much like that of a laser
printer. It consists of a metal cylinder covered with a layer of
semi-conductive material. The drum is given a positive electrical
charge before each use; as it is subjected to the light reflecting
off your original, the areas hit by light (i.e. the areas that are
white on your original) lose their positive charge. The pattern
of dark and light in your original image is imitated by a pattern
of positive and neutral electrical charges on the drum. The drum
rotates at the same rate that the light beam moves across the original
document, so the pattern of electrical charges on the drum is built
from one end of the image to the other. Since the circumference
of the average drum is much smaller than the length of a piece of
paper, a page is typically copied in several distinct chunks. The
entire process occurs so quickly that, to the casual observer, the
copier seems to copy an entire page at a time.
Coating the drum with toner
Like a laser printer, a photocopier uses "dry ink," or toner. Toner
consists of a fine powder made of negatively-charged plastic particles
that have been blended with a black pigment. When the toner cartridge,
which houses the copier's toner, comes in contact with the electrically-charged
photoreceptor drum, the negatively-charged toner particles are attracted
to the positively-charged areas of the drum, forming the characters
and images of your document.
Printing the page
A sheet of paper, which has been given an electrical charge by the
copier's corona wire, is fed past the photoreceptor drum. The toner
particles that are clinging to the drum now become attracted to
the positive electrical charge on the paper. The toner transfers
itself to the page, and the image is formed on paper. In order to
fuse the toner particles to the page permanently, the page is fed
through a pair of Teflon-coated rollers (called the fuser). The
toner particles are melted and pressed into the paper fiber, and
the paper is shot out onto the paper tray for you to pick it up.
Back to General Printer Tips
Save money on printer stuff now
Search below for great deals on all of your printing needs, including
printer cartridges, toner cartridges, ink refill kits, cleaning
cartridges, printer paper, and much more.
|
