Printer

A computer peripheral which produces output to paper allowing us to view the data away from the computer.

Types include;
- laser,
- ink jet,
- dot matrix

[Hewlett-Packard Laserjet 6l]

Use

Used for Computer printouts such as;

Letters (word processing)
customer statements (accounting)
House plans (CAD - often a plotter used)
Brochures, fliers, small publications (Desktop publishing )

Classification

There are many ways to classify printers these include;

Print method
Impact or non-impact printers.
Dot Matrix or Shaped
Speed

Print method

	Character Printers which print one character at a time
	Line Printers which print one line at a time.
	Page Printers which print whole pages at a time.

Impact or non-impact printers.

	Impact printers hit inked ribbons against paper
	Non-impact use other means of forming a character image on the paper eg. Thermal, electrostatic, light or ink jet.

Dot Matrix or Shaped

	Dot matrix character each character is produced by printing the most appropriate dot combination.
	Shaped character each character is produced by use of the appropriate whole character symbol as on an ordinary typewriter.

Speed

Low speed
(10 characters per second to approximately 300 lines per minute.)
Examples include; Dot Matrix, Daisy Wheel, Thermal, Inkjet, Lasers

Medium to High Speed
(typically 300 - 3000 lines per minute.) These printers are used principally on minicomputers and main frame computers. Many line printers print 120 or 130 characters .
Examples include; Laser Printers, Line Printers

Many dot matrix printers are designed to take both lineflow (continuous) paper and with the addition of an automatic sheet feeder, may take cut sheet (photocopy type) paper. It is possible on many printer to have two "bins" so that for example, one can be used for plain paper, the other for pre-printed letterhead.

Diagnosis

Exercise

List steps you should take if your printer does not print. You should refer to the manual supplied with the printer you use.
Troubleshooting

Printer types

There are many printer types. As technology evolves, our ability to print onto different materials also evolves.

Common printer types include

Currently popular printers
Impact dot matrix, Inkjet, Laser, Bubblejet

Older style printers
Daisy Wheel, Thermal, Line

Future possibilities include;
Continuous screen printing printer - for the textile industry. A printer that will print a pattern directly onto cloth.

Impact dot matrix

Impact dot matrix printers were until recently the most popular and widely used low speed printers (superseded by inkjets). They are relatively inexpensive, have speeds from 30 cps (characters per second) to 200 cps, and can produce a variety of charcter sets (ie sets of symbols which the device can print)..

They are limited by their

speed,
noise (impact printers!) and
print quality.

eg. - Epson FX-80, Star NX-10, Huston Instruments JetPRO

Basic features:

A print head made up of metal pins, strikes a ribbon to form characters.
Noisy in operation
Has a selection of Print speeds and quality.
Generally tractor feed with continuous stationery
Carbon Copies may be made.
Print Ribbons are used until the print fades (long life).

Inkjet/Bubblejet

[Hewlett-Packard deskjet 690c]

Inkjet/bubblejet
These are non-impact character matrix printers which fire ink droplets onto the paper by using an 'electrostatic field'.

Ink may be 'fired' at the paper, through small holes in the print head
cartridges holding the ink are used, and generally discarded when ink runs out.
Quiet in operation
Has a selection of Print speeds and quality.
May use tractor feed or A4 cut sheet

examples:HP Thinkjet, HP Paintjet

Laser

[Hewlett-Packard Laserjet 6l]

Laser

A non-impact dot matrix printer using a process similar to that of a photocopy machine to form a page image on a drum

Print a page at a time.
Quiet in operation
Toner cartridges used to store ink.
Generally cut sheet A4 and smaller

Example printers

HP Laserjet Series, IBM 4019 Laser Printer

Daisy wheel

exchangeable print heads which look like 60 mm diameter spoked rimless wheels, with individual characters located sideways on the end of each spoke.

Low Speed Printer

impact shaped character printers with typical speeds of about 40 cps.
give very high quality print.
They are slow, noisy and relatively expensive.
To print each character the wheel is rotated and the appropriate spoke is struck against an inked ribbon.
Daisywheel printers are used in applications where print quality must be high even at the cost of slow speed.
Are rapidly being replaced with laser printers..

For example the user might want letters to be produced which look as if they are personally typed.

Thermal

Non-impact character matrix printers which print onto special paper using a heated print head.
Print head heats a thermal ribbon that transfers wax to paper.

They are very quiet and this gives them a big advantage for some applications eg in hospitals

Thermal wax transfer printers are used for presentation graphics and handouts. Create bold colours at a reasonable cost. The print head in a thermal wax transfer printer warms a ribbon that react to heat, producing an image that is transferrred to paper.

Line

[Line printer]

Line Printers
.these are impact shaped-character printers.

The main types are:

Drum printers
Chain printers
Band printers

The drums, chains or bands rotate at constant speed and are struck by hammers as the required characters pass the print positions.
Characters do not get printed one at a time, from left to right, instead are printed in the order in which they pass under the hammer.
By using continuous stationery with interleaved carbon up to 7 copies can be obtained at a time.
The band and chain printers are similar in principle but the bands which are made of steel may be exchanged quite easily to provide a variety of character sets.