The Computer Revolution/Peripherals/Printers
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[edit] Dot Matrix Printers
The dot matrix printer, also known as a dot character printer, forms each character as a group of small dots, using a group of wires located in the printing element. It is usually used these days to print multipart forms (like carbon copies) and address labels. The tractor and sprocket mechanism in these types of printers can handle thicker media better than laser and ink jet printers.
The dot matrix printer uses one or two columns of dot hammers that move across the paper. The hammers hit the ribbon into the paper which causes the ink to be deposited, similarly to a typewriter. The more hammers in the printer the higher the resolution of the resulting image. Though those wishing to have any sort of resolution with anything other than text would do better to use one of the other varieties of printer since Dot matrix printers can be as expensive but not as multifunctional than the inkjet or laser printers. Another big disadvantage is the noise factor output of the dot matrix printers.
Since Inkjet and laser printers are quite fast with the printing, the print speeds are based on ppg (pages per minute), which is usually indicated on the specifications. Dot matrix printers are different in that the speed of the printer itself is based on cps (characters per second) and varies between 50 to 500 cps depending on the resolution desired. Dot matrix printers are able to print a few pages per minute but will not equal to the amount of pages that an inkjet and laser printers can print.
[edit] Ink jet Printers
- Ink
The ink used in Ink jet printers comes in small cartridges which are compatible for your printer. However the cartridges do vary, depending on your printer the manufacturer will designate a brand for your printer and continue on to explain the reason for purchasing a new cartridge. But not all cartridges need to be discarded, with a growing number of purchased ink jet printers across the world. People are turning to a more inexpensive way of refilling their ink. Through cartridges which are refillable and even in some cases , are permanently installed. These new techniques of refilling your printer have proven to be less expensive than purchasing a brand new cartridge and allow the same quality of printing. Although in some cases manufacturers have warned against this , since it could void your warranty.
Inkjet printers work in a sense that the printer distributes hundreds of thousands of ink droplets onto your paper, eventually forming an image with high quality. Each droplet comes from a nozzle (a printer contain up to six-hundred nozzles) and is then sprayed down onto the page, the only drawback of this system. Is that the ink is still wet when document is fed out and if touched immediately the ink swill smear blemishing the image.
- Quality and the right inkjet printer
Inkjet printers are the basic standard of quality, depending on what type of inkjet printer and purpose you’ll use your printer for. If the printer is used for office use then a multifunctional printer is capable of scanning and faxing, which should yield a good quality for printing. But if you’re a photographer and print high quality photos, than a snapshot printer is more practical, since it’s specially designed to print out high quality photos with good saturation of color. For the best quality relating to printing graphics or high quality text then a laser printer is the best candidate. However, laser printers do not incorporate the use of inkjet technology and are more expensive.
[edit] Laser Printer
A laser printer is a type of computer printer that quickly produces high quality text and graphics on plain paper; compare with other type of printers, such as impact printers. The first laser printer was called EARS, was developed by Xerox and was completed in November of 1971. Laser printers can mix text and graphics, including different fonts, character sizes, and images. The laser printer uses drum and laser technology: the laser shoots shapes and letters onto the drum, from these images created from the lasers, the drum has knowledge of where to pick up the black powder, other wise known as toner. The light produced by the laser changes the electrical charge of the drum temporarily. Toner is used by laser printers rather than liquid ink. After the drum has picked up the powder it is applied to the paper still in a powder form. The final step of laser printing is the heat and pressure applied to the paper. By heating the paper the powder melts into an ink making permanent impressions on the paper in the form the laser mapped out. Advantages of laser printers over inkjet printers include faster print speed, no smearing, higher resolution,and lower cost . The resolution of laser printers ranges from 300dpi to 1200dpi which allows the resolution to be one of the major advantages of the laser printer. The low cost is only true for monochrome laser printers, those only using black toner, but when purchasing a laser printer with multiple toner ability the cost tends to jump drastically. In terms of graphics and the laser jet printer, the quality is good but the amount of memory required by the printer is very large and without a high memory printer the graphics will lack quality. The speed of laser printer ranges from 4-20 pages per minute, with the average being on the lower end at 6 pages per minute
[edit] Photo Printers
Photo printers mean you can finally produce true photo quality, you can print your precious memories with confidence. You can't distinguish their output from photos that were printed from film in the conventional process. There are essentially three categories of photo printers and they are ink jet photo printers, second is dedicated photo printers and lastly is the professional photo printers.
- Inkjet photo printers
These offer at least one photo feature but can also function as all-purpose printers. They print from business applications reasonably well, though often at a very slow pace. This is the category to consider if you want a single, all- purpose printer. You should also consider it if you want a second printer just for photos.
- Dedicated photo printers
These are typically limited to printing on special-purpose—usually glossy—paper. They may also print only on relatively small paper sizes, often 4 by 6 inches. To date, you can find these in both ink jet and thermal-dye varieties.
- Professional photo printers
These printers may also be dedicated photo printers, but their key characteristic is that they offer at least tabloid-size output (11 by 17 inches). Some can print photos at much larger sizes.
[edit] Printing technology
Printers are routinely classified by the underlying print technology they employ; numerous such technologies have been developed over the years.
The choice of print engine has a substantial effect on what jobs a printer is suitable for, as different technologies are capable of different levels of image/text quality, print speed, low cost, noise; in addition, some technologies are inappropriate for certain types of physical media (such as carbon paper or transparencies).
Another aspect of printer technology that is often forgotten is resistance to alteration: liquid ink such as from an inkjet head or fabric ribbon becomes absorbed by the paper fibers, so documents printed with a liquid ink sublimation printer are more difficult to alter than documents printed with toner or solid inks, which do not penetrate below the paper surface.
Checks should either be printed with liquid ink or on special "check paper with toner anchorage".[1] For similar reasons carbon film ribbons for IBM Selectric typewriters bore labels warning against using them to type negotiable instruments such as checks. The machine-readable lower portion of a check, however, must be printed using MICR toner or ink. Banks and other clearing houses employ automation equipment that relies on the magnetic flux from these specially printed characters to function properly.
[edit] UV printers
Xerox is working on an inkless printer which will use a special reusable paper coated with a few micrometres of UV light sensitive chemicals. The printer will use a special UV light bar which will be able to write and erase the paper. As of early 2007 this technology is still in development and the text on the printed pages can only last between 16-24 hours before fading.[2]
[edit] References
Here is a link that lists some of the more important features when buying a photo printer: http://www.pcmag.com/article2/0,1895,1645744,00.asp
