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09 printers

  1. Printers
  2. The printer is computer peripheral, & output device that accepts text and graphic as input, & prints or illustrations on paper as a hard copy in the form of documents or transparencies etc..
  3. Types There are four major types of printers. 1. 2. 3. 4. Impact printer Sprayed-ink printer Laser printer Plotters.
  4. Impact Printers 1. 2. Daisy Wheel Dot Matrix
  5. Daisy wheel printer
  6. Daisy wheel The printer look like daisy contains a disk made of plastic or metal on which letters and symbols are placed on each patel. When printer needs to print a character, it sends the signal to mechanism called printhead , the printhead rotates the daisy wheel until the desired letter is in place and facing the paper then a electromechanical hammer called Solenoid strikes the back of the character contained petal, forcing the character to hit an ink ribbon, leaving an impression of the character on the paper.
  7.  Daisy wheel printing speed is measured in character per second and standard speed is 10 to 50 characters per second.  Printer work like typewriter and best in multi-copy applications, it can’t print graphics.
  8. Dot Matrix This is an other type of impact printers here printhead contains row of pins. The pins are wrapped with coils of wire to create solenoid, to trigger a particular pin the printer controller sends a signal to printhead , which energize the wires, this makes wires into electromagnet which repel the print pin towards ribbon and printing dots in column and rows and making letters and numbers on paper.
  9. Initialy 9 pins used but later 17 and 24 pin models also introduced for fine output print. Its standard speed about 50 to over 500 cps.
  10. Dot Matrix
  11. Sprayed-ink Printers 1. 2. Inkjet Bubble jet
  12. Inkjet Inkjet printers considered as sprayed-ink on paper. this uses cartridge which contains ink, pump and a ink nozzle to complete printing. when computer send print command then printhead at cartridge energize Piezo-actuator which spraying ink then nozzles makes shape letters, words or images on paper. Ink-jet printers are capable of producing high quality print. A typical ink-jet printer provides a resolution of 300 dpi, also newer models offer higher resolutions.
  13. Inkjet
  14. Bubble jet printer Bubble-jet printers use special heating elements to out the ink. Like inkjet printers this type of printer also uses cartridge which have several small chambers inside, bottom of each chamber have a small pinholes, these pinholes are used to spray ink on the page and print characters and images with fine resolution.
  15. If particular chamber needs to spray ink, then electric signal is sent to heating element, when element is energized, it creates vapours, then these vapours push ink towards pinhole and forms a bubble of ink.
  16. Bubblejet
  17. Laser Printers Laser printers accept computer signals and convert it to laser beam to produce an image on a drum, toner touches drum and coat with inked powder and finally convert this inked image to a paper. Photocopiers also work on same procedure. Laser printer also called page printers and use memory to print high-resolution text & graphics outputs, resolution ranges from 300 to 1200 dpi. The speed of laser printers ranges from about 5 to 20 ppm.
  18. Printer Components         Printer Controller unit Corona wire unit Laser beam converter unit Photosensitive drum unit Toner unit Paper feeding unit Fuser unit Exit rollers unit
  19. How Laser printer works
  20. 1. Text or graphics base data stream is sent to the printer. 2. The printer controller circuit receive input signals and manages how to print this data. 3. Here this controller circuit done two jobs first it activates the corona wire. This is a high-voltage wire generate static electric charge to anything nearby, second computer data signals converts into laser beam.
  21. 4. 5. The corona wire charges up the photoreceptor drum so the drum gains a positive charge spread uniformly across its surface. The circuit activates the laser to draw the image of page onto the drum using mirror, when laser beam hits the drum, it removes positive charges and creates negative charges on drum and transfer image on the drum.
  22. 6. An ink roller (toner) touching drum and coats it with tiny particles of powdered ink then this inked image of the page remains on the drum. 7. A sheet of paper from a hopper on the other side of the printer feeds up toward the drum. As it moves along, the paper is given a strong electrical positive charges by another corona wire.
  23. 8. When the paper reaches near the drum, its positive charges attracts the negative charges away from the drum, then inkedimage is transferred from the drum to paper surface. 9. The inked paper passes through two hot rollers from fuser unit. The heat and pressure from the rollers press toner particles permanently into the paper. 10. Finally exit rollers get printed paper out, this output is hot for a while.
  24. Laser print processes 1. EP print process: This technology uses a combination of static electric charges, laser light and toner. 2. HP print process: This technology is relatively same as EP but it uses charging roller instead of corona wire and developing roller in the toner.
  25. Laser print processes 3. LED print process This technology uses LEDs instead of laser light, and these LEDs are near to drum, having advantage of low cost and laser beam hazardous.
  26. Plotters Plotters are large-scale printers, These are commonly used for technical drawings such as engineering drawings or architectural designs. The two basic types of plotters are called 1. 2. Flatbed plotters Drum plotters.
  27. Flatbed Plotters Flatbed plotters one of the graphics output device that draws by moving a pen in both horizontal and vertical directions over a sheet of paper; the overall size of the drawing is limited by the height and width of this bed.
  28. Flatbed Plotters
  29. Drum Plotters Drum plotters, also called upright plotters, this type of plotters are vertically positioned. Printing image is on a drum where paper rolls on it and making a fine image, text or design as large scale printing.
  30. Drum Plotters
  31. Printer Characteristics Color: Color printers are more expensive to operate since they use two ink cartridges one is colored and other is black ink, these are important for maps and designs. Resolution: Printer resolution (sharpness) is usually measured in dots per inch (dpi), standard resolution is 300 - 600 dpi.
  32. Printer Characteristics Speed: Speed of printer is based on page sent, Color printers are slower. Latest and expensive printers are much faster. Memory: Memory used to store print commands sent by computer, Most printers come with a small amount of memory that can be expanded by the user.
  33. Other Printers
  34. Portable printers Portable printers are lightweight using a battery instead of power from the computer. Usually they maintains basic print resolutions suitable for plain text printing.
  35. Digital Photo Printers Many middle range printers print photo quality images. Usually color printers, specially photo print with greater resolution & image quality.
  36. Network printer This type of printer is installed in LAN or Wireless LAN (WLAN) environment and common printing facility to all network users.
  37. Multifunction printers: This type of printer contains High-quality color printing, Fax machine, Color copier, Scanner, Telephone. facilities in one device.
  38. 3D Printers This type of printer creates computer-aided design 3-D applications. The printer is fast, versatile and simple, allowing engineers to produce a range of concept models and functional test parts of any design.