4. DEVICES USED FOR HARD COPY
A plotter is a special output device used to produce hard copies of
large graphs and designs on paper.
They are used to draw construction maps, engineering drawings,
architectural plans and business charts.
The plotter is either a peripheral component that can be add to a
computer system or a standalone device with its own internal
They are mostly used by engineers and designers who need to draw
They are also used by marketing agents for printing huge
advertisements and posters.
Types of plotters
6. FLAT-BED PLOTTER
A flat-bed plotter is a mechanical device used with many CAD
programs for designers.
The paper remains stationary on a flat surface.
A pen moves across it horizontally and vertically on the paper.
This plotter may use several different pen colors to create the
The size of the graphic is limited to the size of the flat-bed plotter's
7. INKJET PLOTTER
The inkjet plotter creates an image by spraying small droplets
of ink on a paper.
It is a popular choice for advertising agencies and graphic
It is used generally for printing large outputs, such as banners,
billboards and large signs often seen along roadsides.
Inkjet plotters typically produce better quality graphics than
other plotter types.
8. DRUM PLOTTER
A drum plotter is also known as roller plotter.
It consists of a drum or roller on which a paper is placed.
The drum rotates back and forth to produce the graph on the paper.
It also consists of mechanical device known as robotic drawing arm
that holds a set of colored ink pens or pencils.
The robotic drawing arm moves side to side as the paper are rolled
back and forth through the roller.
In this way, a perfect graph or map is created on the paper.
This work is done under the control of computer.
Drum Plotters are used to produce continuous output, such as
plotting earthquake activity.
A printer is an external output device that takes data from a
computer and generates output in the form of graphics / text on a
The printed output is a permanent form of output.
In early days, printers were mostly monochrome but nowadays
color printers are also available.
Printers are categorized according to whether or not the image
produced is formed by physical contact of the print mechanism
with the paper.
Types of printers
11. IMPACT PRINTER
An impact printer makes contact with the paper.
It usually forms the print image by pressing an inked ribbon
against the paper using a hammer or pins.
They are noisy.
Types of impact printers
12. DOT-MATRIX PRINTER
The dot-matrix printer uses print heads containing from 9 to 24
pins / tiny hammers.
These pins individually strike an inked ribbon to produce patterns
of dots on the paper.
These dots form individual characters.
The general rule is: the more pins, the clearer the letters on the
Dot-matrix printers are inexpensive but noisy.
They can also print graphics, although the reproduction quality
Typically they print at speeds of 100-600 characters per
15. DAISY-WHEEL PRINTER
The daisy wheel is a wheel made of plastic or metal on which
characters are mounted along the outer edge.
To print a character, the printer rotates the wheel until the desired
letter is facing the paper.
Then a hammer strikes the wheel, forcing the character to hit an
inked ribbon to leave an impression of the character on the paper.
Daisy-wheel printers cannot print graphics.
They are noisy and slow.
They can print 10 to 75 characters per second.
18. DRUM PRINTER
A drum printer consists of a solid, cylindrical drum that has raised
characters for each print position on its surface.
The number of print positions across the drum typically range from 80-
132 print positions.
The drum rotates at a rapid speed.
For each possible print position there is a print hammer located behind
These hammers strike the paper, along the ink ribbon, against the
proper character on the drum as it passes.
One revolution of the drum is required to print each line.
Typically, they print at a speed of 300 to 2000 lines per minute.
20. CHAIN PRINTER
A chain printer uses a chain of print characters wrapped around two
There is one hammer for each print position.
When the correct character appears at the desired print location on the
page, the hammer strikes the paper which presses the paper against a
ribbon and the character located at the desired print position.
As a result, the impression of the character is left on the page.
The chain keeps rotating until all the required print positions on the line
Chain printer are one of the fastest impact printers.
Their speed ranges from 400 to 2500 characters per second.
22. BAND PRINTER
A band printer operates similar to chain printer except it uses a
band instead of a chain and has fewer hammers.
Band printer has a steel band divided into five sections of 48
The hammers on a band printer are mounted on a cartridge that
move across the paper to the appropriate positions.
Characters are rotated into place and struck by the hammers.
Font styles can easily be changed by replacing a band or chain.
24. LINE PRINTER
A high-speed printer capable of printing an entire line at a time.
A fast line printer can print 1,200 to 6,000 lines per minute.
The disadvantages of line printers are that they cannot print
Their print quality is low, and they are very noisy.
25. NON-IMPACT PRINTERS
Non-impact printers do not use a striking device to produce
characters on the paper.
Because they do not use hammers ,they are much quieter.
Non-Impact printers offer excellent speed, print quality and
Types of non-impact printers
27. LASER-JET PRINTER
A laser printer works like a photocopy machine.
It produces highest quality print but is expensive than inkjet printers.
A laser printer place an electrical charge(+ve) on a rotating drum.
Using patterns of small dots, a laser beam conveys information from
the computer to a positively charged drum by placing negative
charge on it.
The drum is then coated with positively charged toner(an ink
powder) which sticks to those areas of the drum only which are
The paper is given a strong positive electrical charge by a wire
known as corona wire.
As the paper rolls by the drum, its positive charge attracts the
negatively charged toner particles away from the drum.
As a result, the toner is transferred to the paper printing the letters
or other graphics on the paper.
A laser printer provide the highest quality print but is more
expensive than inkjet printers.
Laser printers have built-in RAM chips to store documents output
from the computer before print.
The speed of laser printers is high and they print quietly without
producing much noise.
Many laser printers can print eight pages per minute, but faster
laser printers can print 437 pages per minute if each page
contains 48 lines.
31. INK-JET PRINTER
Ink-jet printers also form images with little dots.
Ink-jet printers spray small, electrically charged droplets of ink
from four nozzles through holes in a matrix at high speed onto
Ink-jet printers can print in color and are quieter and much less
expensive than a color laser printer.
However, they are slower than laser printers.
Some new, expensive ink-jet printers print up 1200 or 1400 dpi.
32. THERMAL PRINTER
Thermal printers use chemically-treated paper known as thermal
paper that darkens or turns black when heated by a thermal print
The thermal print head applies heat only to those areas where ink
should be printed.
When the ink becomes cold, it becomes permanent.
Thermal printers do not use separate ink, toner, or ribbon supplies.
They are most commonly used to print items such as receipts and
Color thermal printers can print few colors only.
35. INPUT- OUTPUT DEVICES
These devices are input and output devices at the same time.
Types of input-output devices
Headsets are a combination of speakers and microphones
which makes them input and output device at the same time.
Headsets are a very efficient method for communicating with
friends and family over the internet using communication
software such as Skype and Yahoo messenger.
37. TOUCH SCREEN
A touchscreen is a computer screen that can be used by touching
it with a finger or a stylus pen.
It enables the user to interact directly with what is displayed.
It can be described as a touchpad with a screen built-in to it.
Today, all kinds of devices, both big and small, make use of
However, tablet computers and smartphones have made them
popular and are the most widely known and used products that