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NPP                  Computer Basics and Windows Fundamentals                    55


                  ing.  Each  head corresponds  to a  colour. The  dmbm  {à¨Q>AmD$Q> ^r bo gH$Vo h¢ Ÿ& BZH$s J{V, H$_ J{V
                  printing speed is in the  range of  a slow dot  dmbo S>m°Q> _o{Q´>Šg {à¨Q>a Ho$ ~am~a hmoVr  h¡ Ÿ& bo{H$Z
                  matrix  printer.  The printing  quality  is much  JwUdÎmm ~hþV hr AÀN>r hmoVr h¡Ÿ&
                  better than that of a dot matrix printer.

                  Advantages of inkjet printer                B§H$OoQ> qàQ>a Ho$ bm^
                  (1) Good printing quality.                  (1) AÀN>r JwUdÎmm dmbr {à¨qQ>JŸ& Ÿ
                  (2) Least noise.                            (2) Ý`yZV_ emoaŸ&
                  (3) Low initial cost.                       (3) àma§{^H$ bmJV AË`§V H$_Ÿ&
                  (4) Multicolour, picture, graphics printing fa-  (4) AZoH$ H$ba _| {MÌ, J«m\$ Am{X H$s {à¨qQ>JŸ&
                      cility.

                  Disadvantages of inkjet printer             B§H$OoQ> qàQ>a H$s hm{Z`m±
                  (1) High operational cost. The cost of per page  (1) à{V noO H$s {à¨Q> bmJV A{YH$ hmoVr h¡Ÿ&
                      printing is higher.
                  (2) Low speed of printing.                  (2) {à¨qQ>J H$s J{V VwbZmË_H$ ê$n go H$_ hmoVr h¡Ÿ&

                   1.25 Laser Printer NPP                     1.25 boOa {à¨Q>a

                                                 beam
                                    LASER
                                    SOURCE                        Octagonal Mirror





                                                     Toner                          Rotation
                                                                   Drum


                                                               Scraper


                                                   Heated Rollers
                                   Blank                                         Printed
                                   Papers                                        Papers
                      The Laser Printer works on the principle    `h \$moQ>moH$m°nr _erZ Ho$ {gÕmÝV na H$m`© H$aVm
                  of photocopy machine. The most important part  h¡ Ÿ& BgH$m g~go _hËdnyU© {hñgm amoQ>oqQ>J S´>_ hmoVm h¡
                  of a  Laser Printer is a  rotating  drum, coated  {Og na ’$moQ>mo gopÝg{Q>d nXmW© H$s naV hmoVr h¡ Omo
                  with photosensitive material. Initially the drum  1000V na Amdo{eV {H$`m OmVm h¡Ÿ& Bggo nhbo Bg na
                  charged to about 1000 volts. The laser source is
                  the source of laser beam. This beam completely  \$moQ>mog|{g{Q>d nXmW© H$s naV M‹T>m Xr OmVr h¡ Ÿ& boOa
                  scans the surface of the drum. The scanning of  H$m òmoV boOa ~r_ XoVm h¡ Ÿ& `h ~r_ Am°ŠQ>mJmoZb Xn©U
                  beam is  done by  octagonal rotating  mirror.  H$s ghm`Vm go g§nyU© S´>_ gVh na n‹S>Vr h¡ Ÿ& Ohm± na
                  The spot  on the  drum  where  laser falls,  be-  ~r_ n‹S>Vr h¡ dhm± H$m joÌ AZmdo{eV hmo OmVm h¡ Ÿ& Bg
                  comes uncharged. The Toner is an ink powder  àH$ma go Xr JB© OmZH$mar H$mo S´>_ na Amdoe Ho$ ê$n _|
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