Hard-Copy Devices in Computer Graphics

A hard copy is a printed copy of information from a computer. Sometimes it refers to a printer, so it is called a hard copy because it exists as a physical object. A hard copy is a tangible output that is usually printed. The principal examples are printouts, whether text on graphics, form printers, and also films including microfilms and microfiche is also considered as hardcopy output. 

Hard Copy Output Devices:

It is an electromagnetic device, which accepts data from a computer and translates them into forms understood by users. Output devices:- printers and plotters.

Printers:

The printer is the most important output device, which is used to print data on paper. A printer is an important accessory for any computer system, especially for a graphics system. This is because most of the graphics created using computer graphics have their ultimate utilization in printed form. Printers are of two types impact and non-impact printers.

There are several major printer technologies available. These technologies can be broken down into two main categories with several types in each. Impact printers involve mechanical components for conducting printing. While in non-impact printers, no mechanical moving components are used.

• Impact-printers: It is a type of printer that works by direct contact with an ink ribbon with paper. These printers are typically loud but remain in use today because of their unique ability to function with multiple forms. An impact printer has mechanisms resembling those of a typewriter. These printers have a mechanism whereby formed character faces are pressured against an inked ribbon onto the paper in order to create an image. Example: Dot matrix and line matrix
• Non-impact printers: It is a type of printer that does not hit or impact a ribbon to the printer. They used laxer, xerographic, electrostatic, chemical and inkjet technologies. Non-impact printers are generally much quieter. They are less likely to need maintenance or repairs than earlier impact printers. These printers do not touch the paper but rather use laser techniques, ink sprays, xerographic processes, and electrostatic methods to produce the image on paper. Examples: laser printers, inkjet printers, electrostatic printers.
• Dot Matrix: In the market, one of the most popular printers is the dot matrix printer. These printers are popular because of their case of printing and economical price. Each character is in the form pattern of dots and the head consists of a matrix of pins of size. Oldest printing technology, one character at a time by using a fixed no of pins. These printers are bidirectional and slow in speed.
• Daisy Wheel Printer: It is called a daisy wheel because the print mechanism looks like a daisy, at the end of each petal is a fully formed character that produces a solid line print. These printers are generally used for word processing.
• Advantages:
  • More reliable 
  • Better quality 
  • Font can be changed easily
• Disadvantages:
  • Noise
  • More expensive
• Line printers: It is an impact printer and it is also known as a bar printer. It prints one line of text at a time, they can print 30 to 300 lines per minute. Line printers print the full width of the page, one line at a time, instead of a print head using back end forth across the page.
• Advantages:
  • low cost and more durable
  • high speed
• Disadvantages:
  • printing quality is low.
  • It does not support printing graphics very noisy.
• Ink-jet printers: These printers are non impact character printers based on a new technology. They print characters by spraying small drops of ink onto to the paper. Inkjet printers produce high-quality output with presentable features. They make less noise because no hammering is done and these have many styles of printing modes available. Some models of inkjet printers can produce multiple copies of printing also. The ink in the cartridge of the printers is in liquid form. They have nozzles from which ink is sprayed onto paper and it gets printed.
• Advantages:
  • low cost
  • less overall physical size
  • high quality of printing 
  • capable of printing in vivid color
  • easy to use
• Disadvantages:
  • The print head is less durable
  • high maintenance of cost 
  • cartridges cost is high
  • printing speed is not as speed as laser.
• Laser Printers: These are nonimpact page printers. They use laser lights to produce the dots needed to form the characters to be printed on a page. The laser printer, prints very fast, and it produces high-quality outputs. But this type of printer is too costly. This type of printer makes use of a focused beam of light to transfer text and images onto the paper.
• Advantages:
  • It is not noisy,
  • The work process is fast.
  • Operating cost is low.
  • It can print both text and images.
  • These printers are highly optimized and user-friendly. 
• Disadvantages:
  • It is costly.
  • It can not print multiple copies at the same time.
  • These are not economical. 

Differences Between Impact and Non-impact Printers:

Impact printers	Non-impact printers
Produces character and graphics on a piece of paper by striking it is called impact printing.	A type of printer that produces character and graphics on a piece of paper without striking
It prints by hammering a set of metal pins.	Printing is done by depositing ink in array form.
Here Electromagnetic devices are used.	No electromagnetic device is used.
Faster speeds around 250 words per second.	Slower speed by around 1 page per 30 seconds
Example: dot-matrix printer, line printer	Example – Inkjet printer, laser printer

Plotters:

A plotter is a special output device used to produce hard copies of large graphics and designs on paper, such as contributed maps, and engineering drawings. The plotter is either a peripheral component that you add to your computer system with its own internal processor. It is suitable for applications:

• Architectural plan of the building.
• CAD applications like the design of mechanical components of aircraft.
• Many engineering applications.

Advantages:

• It can produce high-quality output on large sheets.
• It is used to provide the high precession drawing.
• It can produce graphics of various drawings.
• The speed of producing output is high.

Types of Plotters:

• Drum plotter: It consists of a drum. The paper on which the design is made is kept on the drum. The drum can rotate in both directions. Plotters comprised of one or more pens and a pen holder. The holders are mounted perpendicular to the drum surface. The pens are kept in the holder, which can move left to the right as well as the right to the left. The graph plotting program controls the movement of pens and drums.
• Flatbed plotter: It is used to draw complex designs and graphics. The flatbed plotter can be kept over the table. The plotter consists of pen and holder. The pen can draw characters of various sizes. There can be one or more pens and a pen-holding mechanism. Each pen has ink of different color. Different colors help to produce the multicolor design of the document.