2. A computer is a general
Purpose device that
can be programmed
to carry out a finite set
of arithmetic
or logical operations.
Since a sequence of
operations can
be readily changed, the computer can
solve more than one kind of problem.
3. Control unit
Arithmetic logic unit (ALU)
Memory
Input/output (I/O)
Multitasking
Multiprocessing
Networking and the Internet
Computer architecture paradigms
4. In computing, an input device is
any peripheral (piece of computer hardware
equipment) used to provide data and control signals to
an information processing system such as
a computer or other information appliance.
7. An Output Device is any piece of computer hardware
equipment used to communicate the results of data
processing carried out by an information processing
system (such as a computer) which converts the
electronically generated information into human-
readable form.
8. Some types of output are :
Text, Graphics, Tactile and Video.
Types of output devices we need to know about are :
o Monitors.
o Speakers.
o Printers.
o Plotters.
9.
10. In computing, Printer is a peripheral which produces a
representation of an electronic document on physical
media such as a paper or transparency film.
Many printers are local peripherals connected directly
to a nearby personal computer. Individual printers are
often designed to support both local & network
connected users at the same time.
Consumer & some commercial printers are designed
for low-volume, short-turnaround print jobs; requiring
virtually no setup time to achieve a hard copy of a
given document.
11. However, printers are generally slow devices
(30pages/min is considered fast), & the cost per page is
relatively high. This is offset by the on-demand
convenience & the project management costs being
more controllable compared to an outsourced
solution.
The Printing Press remains the machine of choice for
high-volume, professional publishing.
However, as printers have improved in quality and
performance, many jobs which used to be done by
professional print shops are now done by users on
local printers.
12. Printers can be classified by the printer technology they
employ, with many techniques being available as
commercial products. The choice of print technology
has a great effect on the cost of the printer and cost of
operation, speed, quality and permanence of
documents, and noise.
Types of technology are :
Modern Print Technology.
Obsolete and special-purpose printing technologies.
13. The following printing technologies are routinely found
in modern printers :
I. Toner-based printers.
II. Liquid inkjet printers.
III. Solid ink printers.
IV. Dye-sublimation printers.
V. Inkless printers.
14. A laser printer rapidly produces high quality text &
graphics.As with digital photocopiers & multifunction
printers(MFP’s), laser printers employ a xerographic
printing proces.
Another toner-based printer is the LED printer which
uses an array of LEDs instead of a laser to cause toner
adhesion to the print drum.
15. Inkjet printers operate by propelling variably sized
droplets of liquid ink onto almost any sized page.
They are the most common type of printers used by
the consumers.
16. Solid ink printers, also known as phase-change
printers, are a type of thermal transfer printer. They use
solid sticks of CMYK-coloured ink, similar in
consistency to candle wax.
Solid ink printers are most
commonly used as colour
office printers,
and are excellent at
printing on transparencies
and other non-porous media.
17. A dye-sublimation printer (or dye-sub printer) is a
printer which employs a printing process that uses
heat to transfer dye to a medium such as a plastic card,
paper or canvas.
Dye-sub printers are intended primarily for high-
quality colour applications.
18. Thermal printers work by selectively heating regions
of special heat-sensitive paper.
Monochrome thermal printers are used in cash
registers, ATMs, gasoline dispensers and some older
inexpensive fax machines.
19. The following technologies are either obsolete, or
limited to special applications though most were, at
one time, in widespread use :
I. Typewriter-derived printers.
II. Teletypewriter-derived printers.
III. Daisy wheel printers.
IV. Dot-matrix printers.
V. Line printers.
VI. Liquid ink electrostatic printer.
VII. Pen-based plotters.
20.
21. The Plotter is a computer printer for printing vector
graphics.
In the past, plotters were used in applications such as
computer-aided design, though they have generally
been replaced with wide-format conventional printers.
Pen plotters print by moving a pen or other instrument
across the surface of a piece of paper. This means that
plotters are vector graphics devices.
Pen plotters can draw complex line art, including text,
but do so slowly because of the mechanical movement
of the pens.
22. Initially, a number of printer control languages were
created to operate pen plotters, and transmit
commands like “lift pen from paper”, “place pen on
paper”, or “draw a line from here to here”.
Three common ASCII-based plotter control languages
are Hewlett-Packard’s HP-GL, its successor HP-GL/2 &
Houston Instruments DMPL.
23. A plotter is typically used to print large-format graphs or
maps such as construction maps, engineering
drawings and big posters. Plotters are divided into two
types:
1. Drum plotters.
2. Flatbed plotters.
3. Pen plotters.
4. Electrostatic plotters.
5. Inkjet plotters.
24. A drum plotter is also known as Roller Plotter. It
consists of a drum or roller on which a paper is placed
and 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.
25. A flatbed plotter is also known as Table Plotter. It plots
on paper that is spread and fixed over a rectangular
flatbed table.
The flatbed plotter uses two robotic drawing arms,
each of which holds
a set of colored ink
pens or pencils.
Typically, the plot size
is equal
to the area of a bed.
26. Pen plotters have an ink pen attached to draw the
images.
Pen plotters create plots by moving a pen or pencil
over drafting paper. (For some pen plotters, the paper
moves and the epn remains stationary).
They have been the most popular type of plotter.
27. While pen plotters use pens, electrostatic
plotters use electrostatic charges to create images made
up of tiny dots on specially treated paper. These plotters,
unfortunately, use expensive chemicals that are
considered hazardous
Electrostatic plotters produce
high-resolution images
and are much faster than
either pen or ink-jet plotters.
28. The inkjet plotter creates an image by spraying small
droplets of ink onto a piece of paper.
They are available in thermal or piezoelectric models.
Thermal inkjet plotters use heat to apply droplets of
ink, while piezoelectric plotters use charged crystals to
apply the ink.
Inkjet plotters tend to produce better quality graphics
than other types of plotters.
