Hard Copy Devices

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HARD COPY DEVICES

Output that is readable by the user can be categorized into two categories: Output that is readable by the user can be categorized into two categories:

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• Hard copy - Hard copy is a Hard copy - Hard copy is a relatively permanent form of output that canrelatively permanent form of output that can be read immediately or stored for later use, such

be read immediately or stored for later use, such as paper.as paper. Printers Printers are theare the most common hard copy output devices.

most common hard copy output devices. •

• Soft copy - Soft copy is a transient form of output, for eSoft copy - Soft copy is a transient form of output, for e xample, text on axample, text on a screen display

screen display. It is lost . It is lost when the cowhen the computer is turned off unless it mputer is turned off unless it is savedis saved in the main memory or on a

in the main memory or on a disk.disk.

The quality of the pictures obtained from a device depends on dot size and The quality of the pictures obtained from a device depends on dot size and the number of dots per inch,

the number of dots per inch, or lines per inch, that can or lines per inch, that can be displayed. Tbe displayed. To produceo produce smooth characters in printed

smooth characters in printed text strings, higher-quality printers shift dot positionstext strings, higher-quality printers shift dot positions so that adjacent dots overlap.

so that adjacent dots overlap.

Printers are also classified by the following characteristics Printers are also classified by the following characteristics

Quality of type:

Quality of type: TheThe outputoutputproduced by printers is said to be either produced by printers is said to be either letter letter

quality

quality (as good as a typewriter),(as good as a typewriter), near letter qualitynear letter quality, or , or draft qualitydraft quality.. Only daisy-Only daisy-wheel, ink-jet, and

wheel, ink-jet, and laser printers produce letter-quality type. Some dot-matrixlaser printers produce letter-quality type. Some dot-matrix printers claim letter-quality print, but if you look

printers claim letter-quality print, but if you look closelyclosely, you can , you can see thesee the difference.

difference. Speed:

Speed: Measured inMeasured in characters per secondcharacters per second(cps) or (cps) or pages per minute pages per minute(ppm), the(ppm), the speed of printers varies

speed of printers varies widelywidely. Daisy-wheel printers tend to . Daisy-wheel printers tend to be the slowest,be the slowest,

printing about 30 cps. Line printers are fastest (up to 3,000 lines per minute). printing about 30 cps. Line printers are fastest (up to 3,000 lines per minute).

Dot-matrix printers can print up to 500

matrix printers can print up to 500 cps, and laser printers range from about 4 cps, and laser printers range from about 4 to 20to 20 text pages per minute.

text pages per minute. Impact or non-impact

Impact or non-impact:: Impact printers Impact printersinclude all printers that work byinclude all printers that work by striking an ink ribbon. Daisy-wheel, dot-matrix, and line printers are impact striking an ink ribbon. Daisy-wheel, dot-matrix, and line printers are impact printers.

printers. Non-impact printers Non-impact printers include laser printers and ink-jet printers. Theinclude laser printers and ink-jet printers. The important difference between impact and non-impact printers is that impact important difference between impact and non-impact printers is that impact printers are much

printers are much noisiernoisier.. A

A plotter plotter is another hard copy output device that reproduces graphicis another hard copy output device that reproduces graphic images on paper using a pen that is attached to a movable arm. Pen plotters can images on paper using a pen that is attached to a movable arm. Pen plotters can draw complex line art, including text,

draw complex line art, including text, but do so very slowly because of thebut do so very slowly because of the mechanical movement of the pens. When

mechanical movement of the pens. When computer memorycomputer memorywas very expensive,was very expensive, and processor power was very limited, this was often the

and processor power was very limited, this was often the fastest way to producefastest way to produce color high-resolution vector-based

color high-resolution vector-based artwork, or very artwork, or very large drawings efficientlylarge drawings efficiently.. Graphics:

Graphics: Some printers (daisy-wheel and line printers) can print only text.Some printers (daisy-wheel and line printers) can print only text. Other printers can print both text and graphics.

Other printers can print both text and graphics. Fonts

Fonts :: Some printers, notably dot-matrix printers, are limited to one or a fewSome printers, notably dot-matrix printers, are limited to one or a few fonts. In contrast, laser and ink-jet printers are capable

fonts. In contrast, laser and ink-jet printers are capable of printing an almost unlimitedof printing an almost unlimited variety of fonts. Daisy-wheel printers can also print different fonts, but you need to variety of fonts. Daisy-wheel printers can also print different fonts, but you need to change the daisy wheel, mak

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Impact & Non-impact printers

Refers to a class of

Refers to a class of printers printers that work by banging a head or needle against an ink ribbonthat work by banging a head or needle against an ink ribbon to make a mark on the paper. Impact printers include

to make a mark on the paper. Impact printers include dot-matrix printersdot-matrix printers,, daisy-wheeldaisy-wheel

printers

printers, and, and line printersline printers. In contrast,. In contrast, laser laser andand ink-jet printersink-jet printersareare non-impact printers.non-impact printers. The distinction is important because impact printers tend to

The distinction is important because impact printers tend to be considerably noisier thanbe considerably noisier than non-impact printers but are useful for multipart forms such as invoices.

non-impact printers but are useful for multipart forms such as invoices.

Impact printers Impact printers

Of all the printer types, however, impact printers have relatively low consumable costs. Of all the printer types, however, impact printers have relatively low consumable costs. Ink ribbons and paper

Ink ribbons and paper are the primary recurring costs for impact printers. It press formedare the primary recurring costs for impact printers. It press formed character faces against an inked

character faces against an inked ribbon onto the paper.ribbon onto the paper. Types of impact printers

Types of impact printers •

• Daisy wheel printer :Daisy wheel printer : A type of A type of printer printer that produces that produces letter-quality type. Aletter-quality type. A daisy-wheel printer works on the

daisy-wheel printer works on the same principle as a same principle as a ball-head typewriterball-head typewriter. The. The daisy wheel is a

daisy wheel is a disk disk made of plastic or metal on whichmade of plastic or metal on which characterscharactersstand out instand out in relief along the outer edge. To print a character, the printer rotates the disk until relief along the outer edge. To print a character, the printer rotates the disk until the desired letter is facing the paper. Then a hammer strikes the disk, forcing the the desired letter is facing the paper. Then a hammer strikes the disk, forcing the character to hit an ink ribbon, leaving an impression of the character on the character to hit an ink ribbon, leaving an impression of the character on the paper. Y

paper. You can ou can change the change the daisy wheel to print daisy wheel to print differentdifferent fontsfonts.. Daisy-wheel printers cannot print

Daisy-wheel printers cannot print graphicsgraphics, and in general , and in general they are noisy and slow,they are noisy and slow, printing from 10 to about 75

printing from 10 to about 75 characters per secondcharacters per second. As the price of . As the price of laser laser andand ink-jetink-jet

printers

printershas declined, and the quality of has declined, and the quality of dot-matrix printersdot-matrix printershas improved, daisy-wheelhas improved, daisy-wheel printers have become obsolete.

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• Dot matrix printer:Dot matrix printer: A type of printer A type of printer that producesthat produces characterscharactersand illustrationsand illustrations by striking

by striking pins pins against an ink ribbon to print closely spacedagainst an ink ribbon to print closely spaced dotsdotsin thein the appropriate shape. Dot-matrix printers are relatively expensive and do not appropriate shape. Dot-matrix printers are relatively expensive and do not produce high-quality

produce high-quality outputoutput. However, they can print to multi-page forms (that. However, they can print to multi-page forms (that is, carbon copies), something laser and ink-jet printers cannot do.

is, carbon copies), something laser and ink-jet printers cannot do. Compared to

Compared to laser laser andand ink-jet printersink-jet printers,, dot-matrix printers are notorious for making adot-matrix printers are notorious for making a racket.

racket.

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• Line printer:Line printer:A high-speedA high-speed printer printer capable of printing an entire line capable of printing an entire line at one time.at one time. A fast line printer can print as many as 3,000 lines per minute. Because

A fast line printer can print as many as 3,000 lines per minute. Because of theof the nature of the print mechanism, line printers are much faster than dot-matrix or nature of the print mechanism, line printers are much faster than dot-matrix or daisy-wheel printers; The disadvantages of line printers are that they cannot print daisy-wheel printers; The disadvantages of line printers are that they cannot print graphics

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Non-Impact printers Non-Impact printers

Non-impact printers are much quieter than impact printers as their printing Non-impact printers are much quieter than impact printers as their printing heads do not strike the paper.

heads do not strike the paper. A type of A type of printerprinter that does not operate bthat does not operate by striking ay striking a head against a ribbon. The term

head against a ribbon. The term non-impact non-impact is important primarily in that it is important primarily in that it distinguishesdistinguishes quiet printers from noisy (impact)

quiet printers from noisy (impact) printersprinters Types of non-impact printers

Types of non-impact printers •

• Laser printer:Laser printer:A type of A type of printer printer that utilizes a laser beam to produce that utilizes a laser beam to produce an imagean image on a drum. The light of the

on a drum. The light of the laser alters the electrical charge on the drumlaser alters the electrical charge on the drum wherever it hits. The drum is then rolled through a

wherever it hits. The drum is then rolled through a reservoir of reservoir of toner toner , which is, which is picked up by the

picked up by the charged portions of the drum. Finallycharged portions of the drum. Finally, the toner is transferred, the toner is transferred to the paper through a combination of heat and pressure.

to the paper through a combination of heat and pressure.The standard of printThe standard of print is very good and laser printers can also produce very good quality

is very good and laser printers can also produce very good quality printed graphic images too.

printed graphic images too.

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• Ink-jet printers:Ink-jet printers:A type of A type of printer printer that works by spraying ionized ink atthat works by spraying ionized ink at a sheet of paper. Magnetized plates in the ink's path

a sheet of paper. Magnetized plates in the ink's path direct the ink ontodirect the ink onto the paper in the desired shapes. Ink-jet printers are capable of producing the paper in the desired shapes. Ink-jet printers are capable of producing high quality print approaching that produced by

high quality print approaching that produced by laser printerslaser printers.. A typical ink-jet printer provides a

A typical ink-jet printer provides a resolutionresolutionof 300of 300 dots per inchdots per inch, although, although some newer models offer higher resolutions. In general, the price

some newer models offer higher resolutions. In general, the price of ink-jet printers isof ink-jet printers is lower than that

lower than that of laser printers. However, they are also of laser printers. However, they are also considerably slowerconsiderably slower. Another . Another drawback of ink-jet printers is that they require a special

drawback of ink-jet printers is that they require a special type of ink that is apt totype of ink that is apt to smudge on inexpensive copier

Hard Copy Devices