Unit 3: Output Device

Output Device

Instruments that produce data from the computer in a form that a human or another can use.

Printer

A device that takes the information on a screen and transfers it to paper or a hard copy. 

The two basic classes of printers; 

• Impact printers

• Non-impact printers

Impact printers

Uses a printhead containing many metal pins that strike an inked ribbon placed between the printhead and the paper.

Features of impact printers;

• They create the character by striking the paper.

• They print on most types of paper

• Multiple [carbon] copies may be printed at once.

Disadvantages of impact printers;

• Some users find the noisy

• Their speed is relatively slow

• They do not print transparencies

Transparencies

Documents printed on clear plastic film.

Types of impact printers;

• Daisy-wheel

• Line printers

Dot-matrix printers

Impact printers that ‘draw’ a character from a series of dots.

Dot-matrix printers; Speed

Speed: 30-550 characters per second.

What are Dot-matrix printers used for?;

Preparation of bills

Invoices in places like hospitals and stores where carbons copies are needed.

Non-impact printers;

Much quieter than impact printers as their printing heads do not strike the paper

Features of Non-impact printers;

• Higher character-per-second print speed.

• No contact between the print head and the paper.

• Can print transparencies 

• Can print on most types of paper in black-and-white and color. 

Types of non-impact printer; 

• Laser printers 

• Inkjet printers

• Thermal printers

• Plotter

Laser printers;

Uses a laser beam and dry powered ink to produce the print on the paper.

Laser printers; Speed

Speed: Can produce 400 pages of letter-sized paper per minute with high print quality, including full-color photo-quality prints. 

Inkjet printers;

• Cheaper than laser printers but are slower and produce lower-quality prints.

• A non-impact variation of Dot-matrix printers.

• A matrix of fine jets is used to squirt ink at the paper.

• Operate quietly at fairly high speed

Thermal printers;

• Use special heat-sensitive paper. 

• Characters are formed by heated needles placed in contact with thermal paper, forming dark dots.

• Quiet and relatively fast.

• High cost of paper, no choice for print colors, and low durability of the print.

• Used in automatic tele machines, credit card machines, and prepaid phone card dispensers.

Dye sublimation; 

• Use heat to transfer the ink from colored ribbons into the ink from colored reborns into a glass that cools into a glass-like substance on paper. 

• Among the most expensive printers on the market.

• Used by businesses such as advertising agencies and photo Studios

Plotter

Used to produce high-quality quality accurate, large size drawings.

CAD

Computer-Aided Designs

CAM

Computer-Aided manufacture

Multimedia projector;

• Takes an image from a computer screen and projects it onto a large screen or wall so that it can be seen by a large audience.

Modem;

• A device used to allow computers to communicate with others using telephone lines.

Speakers;

• Produces output in the form of sound.

A speaker synthesizer

A device that takes data from a computer and outputs it as spoken words.