Hardcopy Output

Hardcopy Output

A hard copy output is a printed copy of information from a computer. Sometimes referred to as a printout, a hard copy is so-called because it exists as a physical object. The hardcopy output devices are Plotter, Printer.Some of the commonly used hardcopy output devices are as follows:

Printer

Printer is a hardcopy output device that prints text or illustrations and images on paper and in many cases in transparencies and other media. It produces hardcopy output. In evaluating the printer, three criteria are most important as

• Image quality: It is also known as print resolution. The resolution is measured in dots per inch (dpi).
• Speed: Printer speed is measured in number of pages of texts the computer can print each minute.
• Cost of operation: The cost of ink or tonner and maintenance varies with the type of printer.

The printers are differentiated on the basis of quality of type, speed, impact or nonimpact, Graphics and fonts.

Dot matrix Printer

Dot matrix printer is a type of printer that works by using a ‘head’ to hammer a ribbon or film coated with black carbon down on a sheet of paper. It uses impact technology. Each pin makes dot and combination of dots makes characters and illustrations, which is driven forward by the power of a tiny electromagnet. The portion of the printer containing the pins is called the print head. When running the printer, it generally prints one line of text at a time. The characteristics are produced in matrix format. It has speed that ranges from 40 characters per second to 100 characters per second as per the nature of character. There are two variants of dot matrix printer: one with 9-pin and other with 24-pin print heads. As the density of hammers in the 24-pin printer is higher than 9-pin, it produces a superior print quality. They are generally cheaper as they use simple technology and also produce noise while printing. Its print quality is also low which are its disadvantages compared to other advanced printer but it is improving slowly. It is very useful for high volume work. In addition, since they are impact printers, the dot matrix printers can be used to generate multiple copies of same document at time by the use of carbon paper.

Inkjet Printer

Inkjet printers create an image directly on a paper by spraying ink through tiny nozzles. It is capable of producing high-quality print approaching that produced by laser printers. It uses technology of non-impact printer which uses chemical, heat or electrical signals to etch or induce symbols on papers. A typical inkjet printer provides a resolution of 360 dots per inch and they can print from two to four pages per minute and this technology has been used well for production of color printing and elaborate graphics. Four ink nozzles cyan; magenta, yellow and black are used in Color inkjet printer. In general, the price of inkjet printer is lower than that of laser printers. However, they are also considerably slower. Another drawback of inkjet printer is that they require a special type of ink that is apt to smudge on inexpensive copier paper. Inkjet printers require smaller mechanical parts than laser printers, they as especially popular as portable printers.

It has following features

• Print quality is higher in character sets,
• Choice of type set is controlled by program,
• Print quality is quite good than dot matrix.
• Printer has the ability to produce multiple copies of documents in a single print.

Laser Printer

A separate CPU is built into printer to interpret the data that it receives from the computer and to control the laser. Laser beam technology is used to print the characters or images in paper. Printing is achieved by deflecting laser beam on to the photosensitive surface of drum and the latent image attracts the tonner to the image areas.  For the full page print of graphics at 300 dpi at least 1 MB of printer RAM should be needed. For a 600-dpi graphic at least 4 MB RAM should be needed. Laser printer is highly expensive but very popular because of high quality, high speed, and high volume technology, which works in non-impact fashion on plain paper or pre-printed forms. Laser printers are more expensive and faster. It has speed of 10 to 200 pages per minute. It is excellent for high quality works and only works on single color black. It is commonly used in office environments. Laser printer uses the technology of non-impact. They are much quieter than dot matrix and other printer. They are relatively fast, although not as fast as some dot matrix printers. Laser printers are controlled through page description language (PDLs)

Daisy-wheel Printer

Daisy-wheel printer is a type of printer that produces letter-quality type. It works on the principle of ball head typewriter. The daisy wheel is a disk made of plastic or metal on which characters stand out in relief along the outer edge. To print a character, the printer rotates the disk until the desired letter is facing the paper. It only prints characters. It has no ability to print graphics. We can change the daisy wheel to print different fonts. It is noisy slow and less efficient. It has sped to print 10 -75 characters per second.

Plotter

Plotter is a device that draws picture on paper board on command from a computer. As a result, they can produce continuous lines, whereas printers can simulate lines by printing a closely spaced series of dots. It uses various colored pens to draw different colors. It is used to print the large pages in different color as printers are not feasible for that large size of print. The price of plotter is higher than normal printer. Plotter differs from printers in that they draw lines using a pen. They are used in engineering application where precision is mandatory and for printing big and large posters. There are many differences in between printer and plotter as it is of huge size, the speed of printing is also slower. In addition, it prints the page in large size with high-quality print.