Impact Printers
These create text or image by physically making the print head press the ink ribbon and cause the ink deposition on the paper in desired form. They are quite louder in nature when compared to other types of printers. They are famous for their unique features, commonly used in businesses where multi-part forms are printed. The following are different types of printers in impact printing:

  • Dot Matrix
  • Daisy Wheel
  • Line
  • Line Matrix



Dot-Matrix Printers

A dot matrix printer or impact matrix printer is a type of printer with a print head that runs back and forth, or in an up and down motion, on the page and prints by impact- striking an ink-soaked cloth ribbon against the paper. Letters are drawn out of a dot matrix, and thus, varied fonts and arbitrary graphics can be produced. The printing involves mechanical pressure and as a result these printers can create carbon and carbonless copies.Each dot is produced by a tiny metal rod, also called a "wire" or"pin", which is driven forward by the power of a tiny electromagnet or solenoid, either directly or through small levers (pawls). Facing the ribbon and the paper is a small guide plate pierced with holes to serve as guides for the pins.

Advantages

One advantage of dot matrix printers over most other printer types is that the paper is completely connected. This allows you to print long banners that span across several sheets of paper.

Disadvantages

The primary disadvantage of dot matrix printers is the speed it takes for them to print. Each dot is individually printed so a significant amount of time is required to print even one page of paper.Unless they are huge commercial models, dot matrix printers generally produce low-quality print, particularly for pictures.Any type of printer can jam, but dot matrix printers are more prone to jamming, and their jams are more difficult to clear. This is because paper is fed in using two wheels and holes set into the paper. A small tear on the side of a sheet can create a jam and the bits of paper between the wheels make it tedious to fix.

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Daisy Wheel Printers

A daisy wheel printer is a printer that uses a wheel with all the characters on it to produce output. This earlier print mechanism used a plastic or metal hub with spokes like an old-fashioned wagon wheel minus the outer rim. At the end of each spoke is the carved image of a type character. The shape of printer wheel resembles the petals of a daisy flower and hence, it is named daisy wheel printer. To print a character, the daisy wheel rotates so that the required character is positioned just in front of the printer ribbon. The spoke containing the required character is hit by a hammer and strikes the ribbon leaving an impression on the paper placed behind the ribbon. Movement of all these parts is controlled by microprocessor in the printer.

Advantages

The main advantage of using a daisy wheel printer is that the print quality is high because the exact shape of the character hits the ribbon to leave and impression on the paper.

Disadvantages

Daisy Wheel printers are very noisy, slow and the ribbon must be changed frequently.

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Line Printers

The line printer is a form of high speed impact printer in which one line of type is printed at a time instead of printing each character individually. The line printer is typically enclosed in a cabinet that completely seals the unit from the outside world. This used to be essential when line printers were extremely noisy. The two surviving line printer technologies are band printers and line matrix printers. Line printers are still widely used in data centers and in industrial environments and can print multi-part forms at a very rapid rate. High speed line printers print 1000-2000 lines per minute and are therefore useful to print large amounts of address labels, payroll checks, statements or bills.

Advantages

Line printers can print multi-part forms at a very rapid rate. Line printers do not print each character individually. The line printer is typically enclosed in a cabinet to minimize noise level.

Disadvantages

The standard line printer can only use pin feed paper and they can only print black ink.

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Line Matrix Printers

A line matrix printer is a computer printer that is a compromise between a line printer and a dot matrix printer. Basically, it prints a page-wide line of dots. It builds up a line of text by printing lines of dots. Line matrix printers are used for high-speed printing applications in industries such as manufacturing, banking, supply chain and back office environments. In these high-volume printing industries, line matrix printers are used to produce invoices, bank statements, product shipment and transportation documentation. Line matrix printers can print text, bar codes and graphics.

Advantages

When implemented as impact printers, they can be the least expensive to operate per page. Line matrix printers can print text, bar codes and graphics. Line Matrix Printers are the preferred solutions for high-reliability, lowest total cost of ownership and environmental benefits.

Disadvantages

Line Matrix printers have similar disadvantages as Dot Matrix Printers and Line Printers.
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Non-Impact Printers
These produce text or images on paper without striking the paper physically. These are not loud compared to other types of printers. The technologies commonly used in modern and personal home-based are non-impact type. These technologies can print in both mono chrome and colour. The following can be classified under non-impact printing.

  • Toner based (Laser)
  • Liquid ink(Inkjet)
  • Solid ink
  • Dye-sublimation
  • Thermal
  • Bubble jet

Laser Printers

Originally,toner-based printers are only able to print text and images in black and white. It was only recently that coloured toners have been manufactured allowing these printers to print text and images in black and white and coloured. Toners are a kind of powder that is made out of either carbon or synthetic polymers. There are two kinds of toner-based printers that are available in the market today: Laser Printer and LED Printer. The most common is the laser printer. These use laser beams that preciely lights the drum surface during the printing process. Because of this, it is able to produce high quality text and images.

An electrostatic charge is distributed evenly around a light-sensitive device in the printer called a drum. The image or text that is to be printed on the paper is then projected on the drum through some form of light source. This light source keeps the static charge on the drum to stay on the drum. Any portion of the drum that is not lighted will loose the electrostatic charge that was distributed when the printer was started. The paper is then fed. The toner,being in powder form, is immediately caught on the drum and then transferred onto the paper. The toner is then fused on the paper through heat brought about by the light source and the pressure of the roller as it passes out of the printer.

Advantages

One of the advantages of using laser printers is their ability to print on both pages of the paper, allowing many users to cut their paper usage by half. This ability has also lessened the bulkiness of the end printing materials like reports and manuals. Another advantage of laser printers is that they are not prone to water damage that is normally experienced by users of liquid inkjet printers.

Disadvantages

Many health experts have stated that using laser printers, or toner based printers in general, can cause a number of health problems which is not experienced by those that use other kinds of printers. Studies have released that long-term exposure to toners, because of using the printers or replacing the toner cartridges, can cause respiration problems. Laser printers are bulky and heavy, making them difficult to transport. This is due to the additional components the printer needs to carry, which includes an imaging drum and laser beam technology. It is also more costly to replace cartridges for a laser printer.

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Inkjet Printers

An inkjet printer is a peripheral device that places extremely small droplets of ink onto paper to create animage. The dots are extremely small (usually between 50 and 60 microns indiameter). The dots are positioned very precisely, with resolutions of up to1440x720 dots per inch.


In the inkjet printing mechanism, the print head has several tiny nozzles, also called jets. As the paper moves past the print head, the nozzles spray ink onto it,forming the characters and images. An inkjet printer can produce from 100 to several hundred pages, depending on the nature of the hard copy, before the ink cartridges must be replaced.

Advantages

The principal advantage of inkjet printers is the fact that most of them are inexpensive. Even the cheapest inkjet printers are satisfactory for most of the needs of personal computer users. High-end inkjet printers can render digital images on special paper with great quality. The copy from an inkjet printer needs a little time to dry. Another advantage of inkjet printers is their lightweight and modest desktop footprint. Many models are easy to transport.

Disadvantages

Paper designed especially for inkjet printers is heavier than the paper used with laser printers or photocopiers and is somewhat more expensive. Another disadvantage is the fact that most inkjet printers are slow and they are not designed for high-volume print jobs. Inkjet printers are expensive to operate over time compared with a laser printer. It is wiser to use a laser printer to make hundreds of copies per day or thousands of copies per week, than to use an inkjet printer.

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Solid Ink Printers

A solid ink printer is a laser-class printer that uses solid wax inks that are melted into a liquid before it enters the plumbing of the print head.

The maintenance kit prepares the drum before each print job. It clears off any ink left on the drum and then applies a thick layer of silicone oil onto the drum. The print head then begins spraying ink drops on to the rotating drum. All the colors are applied to the drum at the same time. Once the ink is exposed to the drum, it becomes a soft semi-solid. To transfer the ink to paper, the printer sends it through the pre-heater and then the paper passes between the drum and the pressure roller. The ink cools and sets on contact. Because the ink returns to its solid form, there is no drying time. So each print that comes out of the printer is ready to use.

Advantages

The major advantage of solid ink printers is that they produced less waste which is better for the environment. Another advantage is the ability to print on several paper varieties. The shape of the cartridges make them simple to install and replace, the print quality is consistently superior to that of a laser printer, and there are many affordable third-party alternatives to brand-name inks. Solid ink printers also tend to be less expensive to purchase and are smaller in size, which makes them easier to transport.

Disadvantages

Despite many advantages to solid ink printers, there are also anumber of disadvantages. Since the ink needs to be heated, a considerable amount of energy (approximately 50 watts) is required to run the printer.Additionally, the printed ink isn't very durable. It can be scraped off of the paper simply with a sharp edge, like a fingernail, and exposure to direct sunlight for prolonged periods of time can cause fading. Another disadvantage is that the print heads clog frequently. In order to get the heads unclogged a significant amount of ink is wasted. These printers are also notorious for being noisy and pages printed on an ink printer require time to dry otherwise the ink may smear.


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Dye Sublimation Printers

A dye-sublimation printer (or dye-sub printer) is a computer printer which employs a printing process that uses heat to transfer dye onto medium materials such as a plastic card, paper, or fabric. The sublimation name is applied because the dye transitions between the solid and gas states without going through a liquid stage.

During the printing cycle, the printer rollers will move the medium and one of the coloured panels together under a thermal printing head, which is usually the same width as the shorter dimension of the print medium. Tiny heating elements on the head change temperature rapidly, laying different amounts of dye depending on the amount of heat applied. After being heated into a gas, the dye diffuses onto the printing medium and solidifies. After the printer finishes covering the medium in one colour, it winds the ribbon on to the next colour panel and partially ejects the medium from the printer to prepare for the next cycle. The entire process is repeated four times in total: the first three lay the colours onto the medium to form a complete image, while the last one lays the laminate over top. This layer protects the dye from re-sublimating when handled or exposed to warm conditions.

Advantages

Traditionally,the advantage of dye-sublimation printing has been the fact that it is a continuous-tone technology, where each dot can be any colour. Consequently, a dye-sublimation printer produces true continuous tones appearing much like a chemical photograph. The prints are dry and ready to handle as soon as they exit the printer. Since the thermal head doesn't have to sweep back and forth over the print media, there are fewer moving parts that can break down. As the dye never enters a liquid phase, the whole printing cycle is extremely clean; there are no liquid inks to clean up.

Disadvantages

Each of the coloured panels of the ribbons, and the thermal head itself, must match the size of the media that is being printed on and only specially coated paper can accept the sublimated ink. This means that dye-sublimation printers cannot print on a wide range of media. Print heads can also get clogged. Because the sublimated ink is a gas, it does diffuse a small amount before being absorbed by the paper. Consequently, prints are not razor-sharp. For photographs, this produces very natural prints, but for other uses such as graphic design this slight blurriness is a disadvantage. The amount of wasted dye per page is also very high; most of the dye in the four panels may be wasted for a typical print. Once a panel has been used, even to just print a single dot, the remaining dye on that panel cannot be reused for another print without leaving a blank spot where the dye was used previously.
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Thermal Printers

A thermal printer is a low-to-medium resolution printer that produces a printed image by selectively heating coated thermal paper, when the paper passes over the thermal print head. It comprises of these key components:

  • Thermal head — generates heat; prints on paper

  • Platen — a rubber roller that feeds paper

  • Spring — applies pressure to the thermal head, causing it to contact the thermo-sensitive paper

  • Controller boards — for controlling the mechanism

In order to print,thermo-sensitive paper is inserted between the thermal head and the platen. The printer sends an electrical current to the heating elements of the thermal head, which generate heat. The heat activates the thermo-sensitive coloring layer of the thermo-sensitive paper, which changes colour where heated. Such a printing mechanism is known as a thermal system or direct system. The coating turns black in the areas where it is heated, producing an image.Two-colour direct thermal printers can print both black and an additional colour(often red) by applying heat at two different temperatures. The heating elements are usually arranged as a matrix of small closely spaced dots—thermal printers are actually dot-matrix printers, though they are not so called.

Advantages

One advantage is that a direct thermal printer does not make use of ribbons.Instead of ribbons, it uses a special thermal paper. Without use of ribbons,toners and inks, the direct thermal printer cuts down the cost significantly,thereby making the entire process cost --effective as opposed to other form of printing technologies. Another advantage of a thermal printer would be the relative affordability of the machine and its quietness when printing.The greatest advantage of a direct thermal printer is that it can not only print labels in batches but also can print individually. Therefore, there is no extra supply of labels and no waste. Also, an advantage of this printer is that small number of labels can be easily printed out in perfect quality and at high speed. A variety of data can be processed without lowering the speed. Therefore, in case of very large supplies, it can also be done without any problem.

Disadvantages

One disadvantage of direct thermal label printers is that it is more expensive than other types of printers but considering the overall cost reduction on ink,ribbon and toners, it is more advisable to invest a greater amount of money on the purchases of a direct thermal printer. They are sometimes considered to be inefficient since too much heat would mean too much ink is used on an image. This could mean that the image would smudge before the ink dried. Another disadvantage is that the images produced are of poor quality (that is,generally grainy and blotchy), since thermal printers are unable to vary the intensity and dot sizes that make up the produced images.

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Bubble Jet Printers

A bubble jet printer is a sister technology to ink-jet technology and in many ways is very similar, which is why the terms are often used interchangeably. However, there are some important differences between bubble jet printers and ink jet printers.The major difference lies in what is used to propel the tiny droplets of ink through the nozzles. Ink jet printers use crystals to fire the ink and bubble jet printers use heat.

In a bubble jet printer, tiny resistors create heat, and this heat vaporizes ink to create a bubble. The expansion that creates the bubble causes a droplet to form and eject from the print head. A typical bubble jet print head has 64 or 128 tiny nozzles, and all of them can fire a droplet simultaneously.

Advantages

Like Ink jet printers, bubble jet printers are very quiet and can produce beautiful coloured images with photographic quality. Another advantage is their relatively low price when compared to other printer types, such as laser printers.


Disadvantages

The heating elements are under much more stress in bubble jet printers than are the crystals in ink jet printers and are prone to early failure. Whenever any substance is heated to high temperatures, it leaves behind a residue; that residue can eventually clog the tiny openings in nozzles and cause build upa round them which can misdirect the ink droplets. There is no way to clean the nozzles on ink cartridges so there will be a build up of residue on both refurbished and refilled bubble jet cartridges.
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