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What are printers? A printer is an output device that prints characters, symbols, and perhaps graphics on paper. Printed output is generally known as hard copy because it has a relatively permanent shape. Softcopy refers to temporary images such as those displayed on a monitor. Printers are classified according to whether or not the image produced is formed by physical contact of the printing mechanism with the paper. Impact printers have contact; non-impact printers do not.
Impact Printers
An impact printer has mechanisms that resemble those of a typewriter. Form characters or images by striking a mechanism such as a printing hammer or wheel against an ink ribbon, leaving an image on the paper. Impact printers are disappearing; however, you can still come into contact with a dot matrix printer. A dot matrix printer contains a print head of small pins that strike an ink ribbon, forming characters or images. The print heads are available with 9, 18 or 24 pins; the 24-pin head offers the best print quality. Dot matrix printers let you choose between draft quality output; a thicker look of 72 dots per inch vertically, which can be acceptable for draft documents and reports, and near letter quality, a sharper look of 144 dots per inch vertically, which is better suited for displaying a finished product. other people.
Dot matrix printers print between 40 and 300 characters per second (cps) and can print some graphics, although the quality of the reproduction is poor. Colored ribbons are available for limited color use. Dot matrix printers are noisy, inexpensive, and can print through multi-copy forms, creating multiple copies of a page at the same time, which ninimpact printers cannot.
Another type of impact printer is not used with microcomputers. Large computing facilities use high-speed line printers, which print a full line of characters at a time rather than a single character at a time. Some, called string printers, contain characters in a rotating string; others, called stripe printers, contain characters on a rotating stripe. With these machines speeds of up to 3000 lines per minute can be possible.
Non-impact printers
Non-impact printers, which are now used almost everywhere, are faster and quieter than impact printers because they have fewer moving parts. Non-impact printers form characters and images without direct physical contact between the print engine and the paper.
Two types of non-impact printers that are often used with microcomputers are laser printers and ink jet printers.
Laser Printer: Like a dot matrix printer, a laser printer creates images with dots. However, like a copier, these images are created on a drum, treated with a magnetically charged ink-like toner (powder), and then transferred from the drum to the paper.
– There are good reasons why laser printers are so popular. They produce crisp, sharp images of text and graphics, providing resolutions from 300 dpi to 1200 dpi, which is near letterpress quality (NTQ). They are quiet and fast. They can print 4 to 32 text-only pages per minute for individual microcomputers and more than 120 pages per minute for mainframes. (Pages with more graphics print more slowly.) They can be printed in many fonts (font styles and sizes). The more expensive models can print in different colors.
– Laser printers have built-in RAM chips to store the documents that come out of the computer. If you are working in desktop publishing and printing complicated documents with color and lots of graphics, you will need a printer with a lot of RAM. Laser printers also have their own ROM chips for storing fonts and their own small dedicated processor. In order to manage complex graphics and page layouts, a laser printer works with a page description language, a type of software that has become a standard for printing graphics on laser printers. A PDL (Page Description Language) is software that describes the shape and position of letters and graphics on the printer. PostScript, from Adobe Systems, is a common type of page description language; HPGL, Hewlett-Packard’s graphical language, is another.
Inkjet printer – Like laser and dot matrix printers, inkjet printers also form images with small dots. Inkjet printers spray small electrically charged ink droplets from four nozzles through holes in a matrix at high speed onto the paper.
– Inkjet printers can print in color and are quieter and much less expensive than a color laser printer. However, they are slower and print somewhat lower resolution (300-720 dpi) than lasers. Some new and expensive inkjet printers print up to 1200 or 1400 dpi. High resolution output requires the use of special coated paper, which costs more plain paper. And if you’re printing high-resolution color graphics on an inkjet printer, the final print of a single page can take 10 minutes or more.
– A variation of inkjet technology is the bubblejet printer, which uses miniature heating elements to force specially formulated inks through print heads with 128 tiny nozzles. Multiple nozzles print fine images at high speeds. This technology is commonly used in mobile printers.
Things to keep in mind when buying a printer, is the printer easy to set up? Easy to operate? Do I need color? or will black do? Does the manufacturer offer a good warranty and good technical phone support? Otherwise, it is wise to have your own personal printer and know the answer to these questions.