Introduction of printer
A printer is an external output device that takes data from a computer and generates output within the sort of graphics / text on a paper. There are two types of printers.
An impact printer makes contact with the paper. It usually forms the print image by pressing an inked ribbon against the paper employing a hammer or pins. Following are some examples of impact printers.
The dot-matrix printer uses print heads containing from 9 to 24 pins. These pins produce patterns of dots on the paper to make the individual characters. The 24 pin dot-matrix printer produces more dots that a 9 pin dot-matrix printer, which ends up in far better quality and clearer characters. The general rule is: the more pins, the clearer the letters on the paper.
The pins strike the ribbon individually because the print mechanism moves across the whole print line in both directions, i-e, from left to right, then right to left, and so on. The user can produce a color output with a dot-matrix printer (the user will change the black ribbon with a ribbon that has color stripes). Dot-matrix printers are inexpensive and typically print at speeds of 100-600 characters per second.
In order to urge the standard of type found on typewriters, a daisy-wheel printer are often used. It is called daisy-wheel printer because the print mechanism seems like a daisy; at the top of every “Petal” may be a fully formed character which produces solid-line print. A hammer strikes a “petal” containing a personality against the ribbon, and therefore the character prints on the paper. Its speed is slow typically 25-55 characters per second.
In business where enormous amount of fabric are printed, the character-at-a-time printers are too slow; therefore, these users need line-at-a-time printers. Line printers, or line-at-a-time printers, use special mechanism which will print an entire line at once; they will typically print the range of 1,200 to 6,000 lines per minute. Drum, chain, and band printers are line-at-a-time printers.
A line printer consists of a solid, cylindrical drum that has raised characters in bands on its surface. The number of print positions across the drum equals the amount available on the page. This number typically ranges from 80-132 print positions.
The drum rotates at a rapid speed. For each possible print position there’s a print hammer located behind the paper. These hammers strike the paper, along the ink ribbon, against the right character on the drum because it passes. One revolution of the drum is required to print each line. This means that each one characters on the road aren’t printed at precisely the same time, but the time required to print the whole line is fast enough to call them line printers. Typical speeds of drum printers are within the range of 300 to 2000 lines per minute.
A chain printer uses a sequence of print characters wrapped around two pulleys. Like the line printer , there’s one hammer for every print position. Circuitry inside the printer detects when the right character appears at the specified print location on the page. The hammer then strikes the page, pressing the paper against a ribbon and therefore the character located at the specified print position. An impression of the character is left on the page. The chain keeps rotating until all the specified print positions on the road have filled. Then the page moves up to print subsequent line. Speeds of chain printers range from 400 to 2500 characters per minute.
A band printer operates almost like impact printer except it uses a band rather than a sequence and has fewer hammers. Band printer features a dance band divided into five sections of 48 characters each. The hammers on a band printer are mounted on a cartridge that moves across the paper to the acceptable positions. Characters are rotated into place and struck by the hammers. Font styles can easily be changed by replacing a band or chain.
Non-impact printers don’t use a striking device to supply characters on the paper; and since these printers don’t hammer against the paper they’re much quieter. Following are some non-impacted printers.
Ink-jet printers add an equivalent fashion as dot-matrix printers within the form images or characters with little dots. However, the dots are formed by tiny droplets of ink. Ink-jet printers form characters on paper by spraying ink from tiny nozzles through an electrical field that arranges the charged ink particles into characters at the speed of roughly 250 characters per second. The ink is absorbed into the paper and dries instantly. Various colours of ink can also be used.
One or more nozzles within the print head emit a gentle stream of ink drops. Droplets of ink are electrically charged after leaving the nozzle. The droplets are then guided to the paper by electrically charged deflecting plates [one plate has charge (upper plate) and therefore the other has charge (lover plate)]. A nozzle for black ink could also be all that’s needed to print text, but full-colour printing is additionally possible with the addition of needed to print text, but full-colour printing is additionally possible with the addition three extra nozzles for the cyan, magenta, and yellow primary colours. If a droplet isn’t needed for the character or image being formed, it’s recycled back to its input nozzle.
Several manufacturers produce color ink-jet printer. Some of these printers accompany all their color inks during a cartridge; if you would like to exchange on color, you want to replace all the colours . Other color ink-jet printers allow you to exchange ink individually. These printers are a far better choice if user uses one color quite other colors. These printers produce less noise and print in better quality with greater speed.
A laser printer works like a photocopy machine. Laser printers produce images on paper by directing a beam at a mirror which bounces the beam onto a drum. The drum features a special coating thereon to which toner (an ink powder) sticks. Using patterns of small dots, a beam conveys information from the pc to a charged drum to become neutralized. From all those areas of drum which become neutralized, the toner detaches. As the paper rolls by the drum, the toner is transferred to the paper printing the letters or other graphics on the paper. A hot roller bonds the toner to the paper.
Laser printers use buffers that store a whole page at a time. When an entire page is loaded, it’ll be printed. The speed of laser printers is high and that they print quietly without producing much noise. Many home-use laser printers can print eight pages per minute, but faster and print approximately 21,000 lines per minute, or 437 pages per minute if each page contains 48 lines. When high speed laser printers were introduced they were expensive. Developments within the previous couple of years have provided relatively low-cost laser printers to be used in small businesses.
Advantages of Laser Printer
The main advantage of electrostatic printer is its speed & efficiency at which it prints high-quality quality graphics & text.
- Laser printers produce high-quality output as compared to other printers.
- Laser printers are quite and doesn’t produce disturbing sounds.
- They are also capable to produce color prints.
Disadvantages of Laser Printer
The main disadvantage of electrostatic printer is its cost, they’re relatively costly as compared to other printers.
- The maintenance, repair & servicing charges also are high of those printers.
- Laser printers emit bit of ozone and are hazardous to health and therefore the atmosphere.
Read more: Computer Fundamentals
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