B Types of printers

A dot-matrix printer uses a group, or matrix, of pins to create precise dots. A print head containing tiny pins strikes an inked ribbon to make letters and graphics. This impact printing technologyallows shops, for example, to print multi-part forms such as receipts and invoices, so it’s useful when self-copying paper is needed. It has two important disadvantages: noise and a relatively low resolution (from 72 to 180 dpi).

- A dot-matrix printer

An ink-jet (also bubble-jet) printergenerates an image by spraying tiny, precise drops of ink onto the paper. The resolution ranges from 300 to 1200 dpi, suitable for small quantities or home use.

A standard ink-jet has a three-colour cartridge, plus a black cartridge. Professional ink-jets have five-colour cartridges, plus black; some can print in wide format, ranging from 60 cm up to 5 metres (e.g. for printing advertising graphics).

- An ink-jet printer

Some ink-jet based printers can perform more than one task. They are called multi-function printersbecause they can work as a scanner, a fax and a photocopier as well as a printer. Some units accept memory cards and print photos directly from a camera.

A laser printer uses a laser beam to fix the ink to the paper. A laser works like a photocopier, a powder called toner is attracted to paper by an electrostatic charge and then fused on by a hot roller.

Laser printers are fast and produce a high resolution of 1200 to 2400 dpi, so they are ideal for businesses and for proofing professional graphics work.

Laser use a page decsription language or PDL which dscribes how to print the text and draw the images on the page. The best-known languages are Sdobe PostScript and HP Printer Control Language.

A professional imagesetteris a typing printer that generatehigh-resolution output (over 3540 dpi) on paper or microfilm. It’s used for high-quality publications.

-A laser printer

A plotter is a special type of printer which uses ink and fine pens held in a carriage to draw detailed designs on paper. It’s used in computer-aided design, maps, 3-D technical illustrations, etc.

- A plotter