Printer
From HvWiki
A output device that produces a hard copy of any desired document.
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Types of Printers
Dot Matrix
Inexpensive, high speed, noisy, and low quality. Prints many small dots to form letters. Dot matrix printers are a kind of impact printer that uses a head with several (typically 9 or 24) solenoid driven pins that strike the ribbon against the paper. Although they are an older technology that has been mostly replaced, they are still useful for form printing.
Daisy Wheel
Slow and high quality letters. Has a wheel similar to that of a type writer to print letters.
Inkjet
Inexpensive, small, reasonable print quality. Microdroplets of ink are pumped out of the print head and onto the paper using a piezoelectric element or a heating element (which creates a bubble that can expand to push ink out).
Inkjet printers are probably the cheapest kind of printer available today, with many low end models costing under $100 dollars. The makes an inkjet printer a very good choice for most home computer users.
Inkjet printers can also be very small. There are many inkjet printers that can fit in a laptop bag for portable printing.
While text output may not be as crisp as with some other printer technologies due to bleeding, the inkjet printer is very good for photos and color graphics. Additionally, there are many types of paper types available for it that allow the printer to be used for T-Shirt transfers, glossy photos, and various other applications.
Laser
Expensive, high quality, and very fast. A positively charge photosensitive drum is selectively discharged by a laser that scans aross the surface as the drum rotates. This produces an electrostatic image on the drum. The surface of the drum then passes by a positively charged roller coated with toner (an ink powder). The toner is attracted to the areas on the drum which have been exposed by the laser. Next, the drum transfers the toner to the paper. The paper then passes through a heated press called a fuser to permanantly melt the toner onto the page.
Color laser printers use a process similar to grayscale versions, except using multiple toner colors (Cyan, Magenta, Yellow, and Black). In some models, the image is printed onto a transfer belt sequentially in each color. In other models, a photo sensitive belt replaces the drum and 4 toner cartridges and 4 laser assemblies are used to apply multiple colors of toner directly to it.
Although a laser printer can be initially very expensive, they typically have a lower consumables cost than inkjet printers. For example, a certain inkjet printer cartridge may cost $40 and last for 2000 pages whereas a laser printer cartridge may cost $280 and last for 25,000 pages. This makes laser printers a good choice for heavy use environments such as offices.
Future Printers
Future printers will be quiet, fast, and produce high quality prints. There will be printers capable of making three-dimensional objects in a short amount of time. 3D printers are currently being experimented on.
