light pen joy stick etc..

light pen:
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http://www.scribd.com/doc/23420309/Introduction-to-Light-Pen

http://www.youtube.com/watch?v=WxQgoeyoWaA


Joysticks:
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http://electronics.howstuffworks.com/joystick1.htm

plotter types and working

types of plotter:
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http://www.ehow.com/list_6382392_plotters-types.html



Working principle of plotter:
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Plotter is a special type of printer that makes use of a pen to create images on paper. Plotter prints vector graphics, whereas printers print alphabets and numerals.

plotter is able to draw lines, whereas conventional printers draw figures through dots. 

A plotter has a movable head that holds a pen like you would hold a pen in your hand. As the paper is fed into the plotter, the head moves forward and backward, creating lines that finally result in drawings of buildings. As a plotter draws lines, it obviously takes more time to draw an image than a conventional printer, which proceeds making dots on paper. Software that makes heavy use of a plotter is auto CAD

Read more: http://www.differencebetween.com/difference-between-printer-and-vs-plotter/#ixzz2ksjJEcUB

Printer working and construction

Type of printer
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Difference between Impact and non-impact printer:

      1)Impact printers operate by having an element strike the paper with ink ribbon in between them. 
          The printheads of non-impact printers do not strike the page. 

2.      Types :

·         Impact printer - Dot-matrix printer

·         Non-impact printer - Inkjet printer, laser printer and thermal printer

3.      Speed :

·         Impact printer - Low printing speed

·         Non-impact printer - Reasonably fast

4.      Quality :

·         Impact printer - Print quality lower in some types

·         Non-impact printer - High quality of output, capable of printing fine and smooth details

5.      Letter quality :

·         Impact printer - Produce near letter quality (NLQ) print only, which is just suitable for printing mailing labels, envelopes, or invoices

·         Non-impact printer - Letter-quality printouts

6.      Consumption :

·         Impact printer - Not commonly used today

·         Non-impact printer - Most commonly used printer today

7.      Tools :

·         Impact printer - Uses ink ribbon

·         Non-impact printer - Uses ink spray or toner powder

8.      Cost :

·         Impact printer - Less expensive 

·         Non-impact printer - More expensive

9.      Durability :

·         Impact printer - Reliable, durable (lasting for a long time)

·         Non-impact printer - Print head is less durable, inclined towards to clogging and damage

1)Dot matrix printer

Impact printer:

The printing mechanism works as follow. The permanent magnetic field holds the hammer spring in stressed, ready to strike position. The driver sends electrical current to hammer coil, which then creates electromagnetic field opposite to the permanent magnetic field. When both fields equalize, the energy stored in the spring is released to strike the hammer against the ribbon and prints a dot on the paper. The hammer printhing mechanism is shown in action at the picture bellow.

The line printer mechanism in action:

During printing process the print-shuttle vibrates in horizontal direction with high speed while the print hammers are fired selectively. So each hammer may print a series of dots in horizontal direction for one pass of the shuttle, then paper advances at one step and the shuttle prints the following row of dots

Refer:

http://mimech.com/printers/line-printer-technology.asp

2)Inkjet printer

 liquid ink in various colors being squirted onto paper and other media, like plastic film and canvas, to build an image. Its a non impact printer.

Ink is pressured by a ink supply pump and flows from the ink bottle to the nozzle.

The nozzle uses ultrasonic vibration to break a pressurized ink stream into small droplets as it leaves the nozzle.

The drops are ejected from the nozzle at high speed. They pass through the charge electrode tunnel / and then on between the deflection electrode.

Here the drops are deflected, by an amount which depends on the charge they were given by the charge electrode.

After the drops leave the region of the deflection electrode they continue to travel in their new direction until they pass out of the printhead and to the substrate.

Drops that aren't required for printing are caught by the gutter and subsequently recycled back to the ink bottle.

3)Laser printer

http://www.computershopper.com/feature/how-it-works-laser-printer

types of scanner

Flat bed, sheetfed, Handheld
==================== 

Scanner

Scanner construction and working
========================

The main component of the scanner is the CCD array. CCD is a collection of tiny light-sensitive diodes, which convert photons (light) into electrons (electrical charge). These diodes are called photosites.


Brighter the light hitting the diode, more will be the electrical charge. The image of the document that you scan reaches the CCD array through a series of mirrors, filters and lenses.


Components:

A lamp is used to illuminate (to throw light) the document.

mirrors, lens, filter and CCD array together make up the scan head.

The image of the document is reflected by an angled mirror to another mirror. The last mirror reflects the image onto a lens. 

Most scanners today use the single pass method. The lens splits the image into three smaller versions of the original. Each smaller version passes through a color filter (either red, green or blue) onto a discrete section of the CCD array. The scanner combines the data from the three parts of the CCD array into a single full-color image.