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NPP Computer Basics and Windows Fundamentals 53
it is surrounded by a small coil. The Head scans h¡ Ÿ& Bgr{bE BgHo$ gmW EH$ N>moQ>r Hw§$S>br hmoVr h¡ Ÿ& h¡S>
a complete line. The character is formed by a EH$ nyar bmBZ H$mo ñH¡$Z H$aVm h¡& `h hoS> àË`oH$ Ho$aoŠQ>a
matrix of dots. These dots are made by pins Ho$ {bE {deof àH$ma H$s ""S>m°Q> _o{Q´>Šg'' ~ZmVm h¡ Ÿ& hoS>
striking on a inked ribbon. The paper is placed
below the ribbon. One approach to get a char- Ho$ A§Xa H$s {nÝg [a~Z na Q>H$amVr h¢Ÿ& Bg_| [a~Z Ho$ ZrMo
acter is to use 5 × 7 matrix. In this matrix 5 aIo H$mJµO na S>m°Q> ~ZVo h¢ Ÿ& EH$ Ho$aoŠQ>a H$mo 5 × 7 Ho$ _o{Q´>Šg
columns and 7 rows are used for one character. _| ~Zm gH$Vo h¢ Ÿ& Bg_| 5 ñV§^ h¡ VWm 7 n§{º$`m± h¡ Ÿ& Aja
The letter 'A' looks as shown above. 'A' H$m _o{Q´>Šg CnamoŠV àH$ma go hmoJm&
The character code to be printed is sent {Og Ho$aoŠQ>a H$mo {à¨Q> H$aZm h¡, CgH$m H$moS>
from computer memory to the printer. The H$åß`yQ>a Ûmam {à¨Q>a H$mo àXmZ {H$`m OmVm h¡Ÿ& {à¨Q>a H$m
printer circuit decodes the code and generates n[anW Bg H$moS> H$mo g_PVm h¡ VWm BgHo$ AZwgma
the necessary control signals to actuate the pins. {d{^ÝZ {g¾b CËnÝZ H$aVm h¡Ÿ& `o {g¾b AbJ-AbJ
These pins move forward to hit the carbon rib- {nÝg H$mo CËVo{OV H$aVo h¢Ÿ& `o {nÝg AmJo AmH$a H$m~©Z
bon placed on paper. The dots form a character. [a~Z na Q>H$amVr h¡ Am¡a dmng Mbr OmVr h¡Ÿ& gm_mÝ`V:
Normally dot matrix printers are bi-directional. S>m°Q> _o{Q´>Šg {à¨Q>a {Û{Xer` hmoVo h¢Ÿ& AWm©V² XmE± go ~mE±
They print from left to right and right to left as d ~mE± go XmE± XmoZm| Va\$ {à¨Q> H$a gH$Vo h¢Ÿ& EH$ ~ma
well. One column of dots is printed at a time. _| EH$ H$m°b_ {à¨Q> hmoVm h¡Ÿ&
The various stages to print a character "B" Ho$aoŠQ>a ''B'' H$mo {à¨Q> H$aZo H$s {d{^ÝZ AdñWmE±
are shown below:
{ZåZmZwgma h¢…
Step1 First strike Step3 Third strike
Step2 Second strike Step4 Forth strike
Step 5: Fifth strike
