Laser Printer User Manual

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1.2.5ThePrintengine
It’s the print enginethat-formsthe actualcharactersand graphics.The
enginedirectsitslaser,apinpointstreamoflightpulses,throughmirrorsand
lensesontothe surfaceof a positively-chargedrotatingdrum.
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Mirror
Lens
Laser beam
~%a~nirr~ mirror
nductor laser diode
Photosensitive drum
Asthelaserscans,it“draws”thepage-mapstoredinyourprinter’smemory.
Wherevera lightpulsestrikes,thattinypartof thedrumdropsto aneutral
electricalcharge.That spot then attractsfine toner powderas the drum
rotatespastthepowdercompartment.
Asthedrumrotatesfurtheritmeetsthepaper.Thepaperitselfis negatively
chargedbypassingbyafinecoronawire.Sinceoppositechargesattract,the
negativepaperclingsto thepositivedrum.Then heatandpressurefroma
rollermeltor~usethedotsoftonerontothepaper,preciselyreproducingthe
image.
Finallythepaperslidesintotheoutputbin.Thepaperusuallycomesoutface
downso it stacksin thecorrectsequence.
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