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Unit3 ppt2 printers

  1. Printer and itsTypes
  2. What isprinter? A printer is an external hardware output device that takes the electronic data stored on a computer or other device and generates a hard copy of it.
  3. Types Of Printer: There are two types of printers: • Impact Printer • Non-Impact Printer
  4. Impact Printer:  Dot Matrix Printer  Daisy Wheel Printer  Line Printer  Drum Printer  Chain Printer Non-Impact Printer: Laser Printer Ink jet Printer
  5. 1:Impact Printers: In this hammers or pins strike against a ribbon and paper to print the text. This mechanism is known as electro-mechanical mechanism. 1.1: Dot Matrix Printers Dot matrix Printers use print heads to shoot ink or strike an ink ribbon to place hundreds to thousands of little dots to form text and images. Today, dot matrix printers are utilized far less than they used to be due to their low quality images and slow print speed when compared to inkjet and laser printers. However, they still see a lot of use in certain sectors such as auto part stores and package delivery companies.
  6. 1.2: Daisy-Wheel Printers It is called daisy-wheel printer because the print mechanism looks like a daisy; at the end of each “Petal” is a fully formed character which produces solid-line print. A hammer strikes a “petal” containing a character against the ribbon, and the character prints on the paper. Its speed is slow typically 25-55 characters per second. 1.3: Line Printers Line printers, or line-at-a-time printers, use special mechanism that can print a whole line at once; they can typically print the range of 1,200 to 6,000 lines per minute. Drum and Chain printers are line-at-a-time printers.
  7. 1.4: Drum Printers An old line printer technology that used formed character images around a cylindrical drum as its printing mechanism. When the desired character for the selected position rotated around to the hammer line, the hammer hit the paper from behind and pushed it into the ribbon and onto the character. 1.5: Chain Printers A chain printer uses a chain of print characters wrapped around two pulleys. Like the drum printer, there is one hammer for each print position. Circuitry inside the printer detects when the correct character appears at the desired print location on the page. The hammer then strikes the page, pressing the paper against a ribbon and the character located at the desired print position. An impression of the character is left on the page. The chain keeps rotating until all the required print positions on the line have filled. Then the page moves up to print the next line.
  8. 2: Non-impact Printers: Non-impact printers do not use a striking device to produce characters on the paper; and because these printers do not hammer against the paper they are much quieter. Following are some non-impacted printers. 2.1: Ink-jet Printers It prints characters by spraying patterns of ink on the paper from a nozzle or jet. It prints from nozzles having very fine holes, from which a specially made ink is pumped out to create various letters and shapes. The ink comes out of the nozzle in a form of vapors. After passing through a reflecting plate, it forms the desired letter/shape at the desired place.
  9. 2.2: Laser Printers Laser Printer is a type of printer that utilizes a laser beam to produce an image on a drum. The light of the laser alters the electrical charge on the drum wherever it hits. The drum is then rolled through a reservoir of toner, which is picked up by the charged portions of the drum. Finally, the toner is transferred to the paper through a combination of heat and pressure. This is also the way copy machines work. Because an entire page is transmitted to a drum before the toner is applied, laser printers are sometimes called page printers.