| Impact printers, as the very name implies means | | | | nozzles. Heat resistant and water based ink is |
| that the printing mechanism touches the paper | | | | used for these printers. |
| for creating an image. Impact printers were used | | | | The latest and fastest printers are Laser Printers. |
| in early 70s and 80s. In Dot Matrix printers a | | | | They use the principal of static electricity for |
| series of small pins is used to strike on a ribbon | | | | printing it as in photocopiers. The principle of static |
| coated with ink to transfer the image on the | | | | electricity is that it can be built on an insulated |
| paper. | | | | object. Oppositely charged atoms of objects |
| Other Impact Printers like Character printers are | | | | (positive and negative) are attracted to each |
| basically computerized typewriters. They have a | | | | other and cling together. For example, pieces of |
| series of bars or a ball with actual characters on | | | | nylon material clinging to your body, or the static |
| them, which strike on the ink ribbon to transfer | | | | you get after brushing hair. A laser printer uses |
| the characters on the paper. At a time only one | | | | this same principle to glue ink on the paper. |
| character can be printed. Daisy Wheel printers use | | | | How Laser Printer works: |
| a plastic or metal wheel. These types of printers | | | | Unlike the printers before, Laser printers use |
| have limited usage though because they are | | | | toner, static electricity and heat to create an |
| limited to printing only characters or one type of | | | | image on the paper. Toner is dry ink. It contains |
| font and not the graphics. | | | | colour and plastic particles. The toner passes |
| There are Line printers where a chain of | | | | through the fuser in the computer and the |
| characters or pins, print an entire line, which | | | | resulting heat binds it to any type of paper. |
| makes them pretty fast, but the print quality is | | | | Printing with laser printers is fast and non-smudge |
| not so good. Thermal printers are nothing but | | | | and the quality is excellent because of the high |
| printers used in calculators and fax machines. | | | | resolution that it can achieve with 300 dots per |
| They are inexpensive to use. Thermal printers | | | | inch to almost 1200 dpi at the higher end. |
| work by pushing heated pins against special heat | | | | Basic components of a laser printer are fuser, |
| sensitive paper. | | | | photoreceptor drum assembly, developer roller, |
| More efficient and advanced printers have come | | | | laser scanning unit, toner hopper, corona wire and |
| out now which use new Non-impact Technology. | | | | a discharge lamp. The laser beam creates an |
| Non-impact printers are those where the printing | | | | image on the drum and wherever it hits, it |
| mechanism does not come into the contact of | | | | changes the electrical charge like positive or |
| paper at all. This makes them quieter in operation | | | | negative. The drum then is rolled on the toner. |
| in comparison to the impact printers. | | | | Toner is picked up by charged portion of the |
| In mid 1980s Inkjet printers were introduced. | | | | drum and gets transferred to the paper after |
| These have been the most widely used and | | | | passing through the fuser. Fuser heats up the |
| popular printers so far. Colour printing got | | | | paper to amalgamate ink and plastic in toner to |
| revolutionized after inkjet printers were invented. | | | | create an image. Laser printers are called "page |
| An Inkjet printer's head has tiny nozzles, which | | | | printers" because entire page is transferred to the |
| place extremely tiny droplets of ink on the paper | | | | drum before printing. Any type of paper can be |
| to create an image. These dots are so small that | | | | used in these printers. Laser printers popularized |
| even the diameter of human hair is bigger. These | | | | DTP or Desk Top Publishing for it can print any |
| dots are placed precisely and can be up to the | | | | number of fonts and any graphics.. |
| resolution of 1440 x 720 per inch. Different | | | | This is how the computer and printer operate to |
| combinations of ink cartridges can be used for | | | | print |
| these printers. | | | | When we want to print something we simply |
| How an Inkjet printer works | | | | press the command "Print". This information is |
| The print head in this printer scans the page | | | | sent to either RAM of the printer or the RAM of |
| horizontally back and forth and another motor | | | | the computer depending upon the type of printer |
| assembly rolls the paper vertically in strips and | | | | we have. The process of printing then starts. |
| thus a strip is printed at a time. Only half a | | | | While the printing is going on, our computer can |
| second is taken to print a strip. Inkjet printers | | | | still perform a variety of operations. Jobs are put |
| were very popular because of their ability to | | | | in a buffer or a special area in RAM or Random |
| colour print. Most inkjets use Thermal Technology. | | | | Access Memory and the printer pulls them off at |
| Plain copier paper can be used in these printers | | | | its own pace. We can also line up our printing jobs |
| unlike thermal paper used for fax machines. Heat | | | | this way. This way of simultaneously performing |
| is used to fire ink onto the paper through the | | | | functions is called spooling. Our computer and the |
| print head. Some print heads can have up to 300 | | | | printer are thus in constant communication. |