History n Working Of Laser Printer


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History n Working Of Laser Printer

  1. 1. Topic Laser Printer
  2. 2. Categories of printer: Impact printer  Non impact printer
  3. 3. Laser printer  Laser printer is a non impact printer.  Laser printer stand for light amplification by stimulated emission of radiation.  Laser printer invented by gray Starweather at in 1969 when American Xerox Corporation held a dominant position in the copier market In 1960. Starweather
  4. 4. Laser printer contained:  A laser beam which is contain negative charge.  Mirror or lens.  Toner hopper attached with developing roller.  Drum core is called photoreceptor that receptor of light.  Fuser .  Discharge lamp.
  5. 5. Steps of printing 1: Charging 2: Exposing 3: Developing 4: Transferring 5: Fusing 6: cleaning
  6. 6. Charging:  When data given to the computer then electronics circuit activates Corona wire which is contain positive charge gives to the drum.  When laser beam strike with the drum then erase the positive charge and creates the negative charge .
  7. 7. Exposing Corona wire falls positive charge on drum . When laser beams which is contain negative charges fall on drum and strike with on positive charges then erase the positive charges and drawing letters and images which is to be printed on this drum. It is also known as electrostatic images.
  8. 8. Developing:  Toner contain a fine black powder. Since it has a positive charge, the toner clings to the negative discharged areas of the drum, but not to the positively charged "background."
  9. 9. Transferring: Before the paper rolls under the drum. This charge is stronger than the negative charge of the electrostatic image, so the paper can pull the toner powder away. The photoreceptor is pressed or rolled over paper, transferring the image. The speed of paper passing through drum is very slow and according to the speed of drum.
  10. 10. Fusing:
  11. 11.  The paper passes through rollers in the fuser assembly where heat of up to 200 °C (392 °F).  One roller is usually a hollow tube (heat roller) and the other is a rubber backing roller (pressure roller). A radiant heat lamp is suspended in the center of the hollow tube, and its infrared energy uniformly heats the roller from the inside.  Some printers use a very thin flexible metal fuser roller, so there is less mass to be heated and the fuser can more quickly reach operating temperature.  If paper moves through the fuser more slowly, there is more roller contact time for the toner to melt, and the fuser can operate at a lower temperature. Smaller, inexpensive laser printers typically print slowly, due to this energy-saving design, compared to large high speed printers where paper moves more rapidly through a high-temperature fuser with a very short contact time.
  12. 12. Cleaning: When the print is complete, discharge lamp removes any electron on photoreceptor.
  13. 13. Advantages  It is very fast printer.  It is no noise during the printing.  A typical laser printer provides a resolution of 1200 dpi or more.  It printing speed is higher than inkjet printer.  The black and white printing cost of laser printer is less than inkjet printer
  14. 14. disadvantages It is very expensive.