. External hardware output device that takes electronic data from computer and transfers information on a paper.
    . Most popular computer peripherals and are used to print text and images.
    . Used almost everywhere where we need hard copy like bills, tickets, reports, documents etc.
    . Manufactures are Canon, HP, Epson etc.
    . Connected to computer in different ways like using USB, Ethernet, Wifi or by sharing another computer's printer in network etc.

   Types of Printers:

           . Classified into two types depending whether they touch paper while printing or not.
           . Impact printers have mechanism to touch paper to create images and text. Ex: Dot-Matrix
           . Non-Impact printer do not physically touch the paper while printing. Ex: Inkjet, Laser, Thermal.

            Laser Printers:

              . Produces high-quality text and graphics by using laser beam.
              . Beam is passed back and forth over negatively charged drum, scanning the image and text directly across printer's photo-receptor.
              . The drum to selectively collects powdered ink also known as toner, which it then transfers to paper.
              . Used in Offices and Business areas where more text is to be printed.
              . It is costlier but output resolution is high.

         Inkjet Printers:

              . Forms images by spraying droplets of ink on the paper.
              . Characters they print are made up of dots like Dot-Matrix printers but these dots are very tiny that we cannot see them.
              . They fire the ink in various ways like heating, piezoelectricity etc.
              . Available for color and white-black printing.
              . Produce good quality text and images.

            Laser Vs Inkjet Printers:

Laser PrintersInkjet Printers
Uses laser beam to print text or image.Uses ink cartridges which is wet to print text or image.
Faster output compared to Inkjet.Slower output compared to Laser.
Cannot print on different types of papers because produces heat.Can print on different types of papers.
Produce sharper text on office paper.Water- based ink, so prints can fade and easily damaged.
Lower cost per page, but high purchase price.Not economical if you print alot.
Heavier and not as portable as Inkjet, need more space.Smaller and can fit in smaller spaces.
Harder to maintain than Inkjet.Easier to maintain.
Contains larger paper tray capacities, refills are fewer.Ink is wasted during automatic cleaning of printers and need to refill more no.of times.
Warm up is required to use.No need of warm up, can be used immediately.
Suitable for fast and high-volume printing. Suitable for offices or small business that need not to print a lot but print high-quality images.

            Thermal Printers:

               . Makes use of heat in order to produce image on paper.
               No involvement of toner or ink like InkJet printers but make use of thermal papers.
               . Most widely used in Grocery stores, Airline, Banking etc.
               . More durable and lower cost compared to other printers.
               Noise free and efficient in mono-chromic printing.
               . Most suitable for barcode related printing.

         Dot-Matrix Printer:

               . Forms images one character per time as print head moves across paper.
               Uses tiny pins to hit an ink ribbon and paper.
               . It is cheapest and most noisy printer producing low quality output.
               . Speed is usually 30 to 550 characters per second.
               . Usually formed in Railway Ticketing, Bus Ticketing, ATMs etc.


               . Stands for Dots Per Inch.
               . Used to measure resolution in printing.
               . It means how many dots fit in one square inch of print.
               . Higher the DPI, higher is the quality of image.
               . If DPI is 600, it means 600 x 600 = 360000 dots will be present per square inch.
               . When working with graphics only on computer screen, 72 DPI is sufficient.
               . To print, it requires minimum 300 DPI to get good quality image.