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BO-ITOM VIEW
When text or graphics are sent by the computer to the printer, a laser beam
is generated by a semiconductor laser diode. This beam is focused by special
scanning mirrors that turn the light beam into a tool that “writes” or “paints”
on the surface of the drum. The areas of the drum touched by the laser beam
lose their negative charge and contain a reverse image of the information sent
from the computer. As the drum rotates, it passes a developer unit that is also
rotating, but in the opposite direction. The surface of the developer unit is
covered with toner (“ink”) which has a negative charge. The neutralized
portions of the drum, containing the information to be printed, pick up
negatively charged toner from the developer unit.
At,this point, paper fed from the paper cassette moves through the transfer
unit, from which it receives a positive charge. As the drum rotates, the
negatively charged particles of toner are attracted to the positively charged
surface of the paper.
A combination of heat and pressure fuse the image to the paper. The paper
is then ejected from the printer.
Finally, acleaning mechanism in the toner cartridge cleans excess toner from
the drum, and a special light beam neutralizes its entire surface. Then the
entire process can begin again.
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