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