Laser Printer Operations Manual

Whentextor graphicsaresentbythecomputerto theprinter,laserbeamis
generatedby a semiconductorlaserdiode.Thisbeamis focusedby special
scanningmirrorsthatturnthelightbeamintoatoolthat“writes”or’’pnnts”
onthesurfaceofthedrum.Theareasofthedrumtouchedbythelaserbeam
lose their negativechargeand containa reverseimageof the information
sentfromthecomputer.Asthedrumrotates,it passesa developerunitthat
is alsorotating,butin the oppositedirection.The surfaceof the developer
unit is covered with toner (“ink”) which has a negative charge. The
neutralizedportionsof the drum,containingthe informationto be printed,
pickup negativelychargestonerfromthe developerunit.
Atthispoint,paperfed fromthepapercassettemovesthroughthetransfer
unit, from which it receivesa positivecharge. As the drum rotates,the
negativelychargedparticlesof tonerareattractedto thepositivelycharged
surfaceof the paper.
A combinationof heatandpressurefusetheimageto thepaper.Thepaper
is thenejectedfromthe printer.
Finally,a cleaningmechanismin the toner cartridgecleans excesstoner
tlomthedrum,anda speciallightbeamneutralizesitsentiresurface.Then
theentireprocesscan beginagain.
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