The Inkjet Printer
So let's first take a look at inkjet printers. Inkjet printers are the most common type of printers that are used in homes. They are affordable, they produce photo quality results and they are more than adequate to suit the needs of a typical home user. The inkjet printer has become so popular in modern times that almost every home has one. They are cheap to buy, compact and usually very reliable.
An inkjet printer works by the printhead moving back and forth across the paper during printing and during this process, the printhead places ink on the paper in very tiny dots. In fact, these dots are so tiny that they are smaller in diameter than a human hair. As these dots are precisely placed, they all combine to create an image on paper. Now to explain how the printer ink is placed on paper here we have an example of an ink cartridge with a built in printhead.
So inside we have the ink, a heating element and a nozzle. So what happens is that the heating element receives a charge of electricity and it heats up. Then as it heats up, it forms a bubble in the ink, as the bubble expands it squeezes out minute drops of ink from the printhead nozzle and on to the paper. Then the cycle is repeated until the print job is done. This particular type of inkjet technology is called thermal bubble, which is used in all HP and Canon printers. Inkjet printers all use liquid ink in their cartridges. Typically cheaper inkjet printers come with two cartridges, one for black and the other one for color.
These printers have the actual print heads built into the cartridges rather than the printer which makes them much cheaper to manufacture. The downside of this however is that the cartridges are far more expensive. The more expensive inkjet printers utilize at least four or more separate cartridges such as one for black, cyan, magenta and a yellow. Often they will also add a photo black and even light cyan and light magenta cartridges.
The Laser Printer
The next type of printer that is also extremely popular is the laser printer. Laser printers come in different sizes from smaller personal ones for home use to quite larger printers for businesses. Laser printers provide the highest quality print when printing text and simple graphics however they are also more expensive than inkjet printers. A laser printer basically works by first placing an electric charge on a rotating drum.
Next a laser discharges a lower electrical charge onto the drum. So basically the laser draws the image that is going to be printed onto the drum itself in an electrostatic form. Next the drum is coated with a powder known as toner and as the drum is being coded with the image, the toner powder only clings to the areas where the laser has left the charge. Then as the paper goes through the printer, the toner is transferred onto the paper. Finally the paper passes through the fuser unit which heats it up to a very high temperature and bakes the toner powder onto the page. The result is a high quality print that is second to none in quality and durability.
The big advantage of a laser printer over an inkjet is that it is able to print at very high speeds and also unlike the inkjet printer the laser prints come out warm and dry and will not smudge. Laser printers also have the advantage of not having a printhead that can clog if left idle or sitting around for long periods of time without use. Because the laser printer utilizes powder instead of ink they can be left idle for long periods of time without any issues occurring.
The Thermal Printer
The next type of printer is called a thermal printer. Thermal printers print by using heat and they also use special paper called thermal paper. Thermal paper is impregnated with a wax based ink and when heat is applied to this ink it turns black. So in a thermal printer, the only process the printhead does is apply heat to the areas where ink should be printed. Then when the ink is cools it becomes permanent. Thermal printers operate very quietly and are commonly used for printing labels and bar codes.
The printers that you see producing your receipts at your local supermarket are using thermal print technology. You will also see them built into most portable EFTPOS machines and they are also the main printers used for labeling. This is due to the fact that they print fast, they don't use ink and they are able to be manufactured to quite compact sizes.
The Dot Matrix Printer
The next printer type is known as the dot matrix printer. The dot matrix printer were very popular years ago however today they are almost nonexistent . They are an old technology that produced mediocre print quality, especially when compared to laser or inkjet printers. They were also very noisy. Dot matrix printers are also known as impact printers. The printer moves across the paper and as it moves the pens on the printhead strike against a cloth ink ribbon. The ribbon then comes in direct contact with the paper producing each character in the form of dots.
Despite being such an outdated form of technology dot matrix printers can print multi copy documents such as carbon copies. They're also very reliable printers and they tend to continue operating for many years without failing. The only real down side to thermal printers is that the printouts tend to be not as UV resistant and they may fade quite fast. Also the printouts are not hard wearing and if exposed to any form of abrasion the print may actually wear off of the paper.
The LED Printer
One of the more recently developed printer types is what's known as the LED printer. These operate in a similar fashion to a laser printer except that the laser and mirrors are replaced by an array of LED's or Light Emitting Diodes. The LED's create a charge on the drum line by line to form the printed image and then the toner is attracted to the drum in the same method as is done with a laser printer. The paper then passes through the drum unit and onto the paper. Finally the paper gets heated to a high temperature by the fuser and it is baked onto the paper.
LED printers are much quieter than a laser printer as they do not have a rotating mirror assembly. This also makes the LED printer more reliable and increases the longevity of the printer.