Dot matrix printers use pins to strike an ink ribbon and transfer ink to paper, forming characters and images from arrangements of dots. They provide low-cost printing but also low resolution and quality. Laser printers use heat and pressure to bond toner particles to paper in the pattern of an image formed by a laser beam scanning a photosensitive drum. They offer higher quality printing than inkjet printers. Printers can be categorized as either impact printers that use a mechanism to transfer ink, like dot matrix, or non-impact printers like inkjet and laser that use other ink transfer methods.

1. Devices that Output
Hard Copy

2. 2
What is a printer?
 An external hardware device responsible
for taking computer data and generating a
hard copy of that data. Printers are one of
the most commonly used peripherals and
they print text and still images on the
paper.

3. 3
Printers
Impact Printers Non-Impact Printers
Daisy
wheel
Dot-
Matrix
Inkjet Thermal Laser

4. Categorizing Printers
Printers fall into two categories:
• Impact printers use a device to strike an inked
ribbon, pressing ink from the ribbon onto the paper.
• Non-impact printers use different methods to place
ink (or another substance) on the page.

5. 5
“Factors affecting print quality”
 (1) DPI:
It is a measurement of printer’s resolution indicating how many ink dots
can be placed by the printer in one square inch. The higher the DPI, the
sharper is image. Image quality – Measured in dots per inch (dpi). Most
printers produce 300 – 1200 dpi.
 (2) Type of printer:
Each type of printer has its own capabilities of printing. Some types of
printers produce high quality print while other produce low quality print.
 (3) Print Mode:
The printing mode may also affect the quality. For example the draft mode
increases the print rate but quality is reduced.
 (4) Toner:
The quality and amount of toner also affects print quality.

6. Dot Matrix Printers
• How Do Dot Matrix Printers Work?
• Performance

7. 7
“Dot Matrix Printer”
• The term dot matrix refers to
the process of placing dots to
form an image.
• Its speed is usually 30 to 550
characters per second (cps).
• This is the cheapest and the
most noisy printer and has a
low print quality. Dot Matrix
were 1st introduced by
Centronics in 1970.

8. 8
How Dot-Matrix works?
• The dot matrix forms images one character at a time
as the print head moves across the paper.
• Uses tiny pins to hit an ink ribbon and the paper
much as a typewriter does.
• This printer arranges dots to form characters and all
kinds of images.
• 9 to 24 vertical column pins are contained in a
rectangular print head. When print head moves across
the paper, pins are activated to form a dotted
character image. These printers can produce carbon
copies along with the originals.

10. 10
“A typical dot matrix output”

11. Dot Matrix Printers - Performance
• Lower-resolution dot matrix printers use nine pins.
Higher-resolution models have 24 pins.
• Speed is measured in characters per second (cps).
Some dot matrix printers print 500 cps.

12. 12
“Advantages/Dis-advantages of
Dot-Matrix”
• Advantages:
• (1) In-expensive.
• (2) Low per page cost.
• (3) Energy efficient.
• Dis-advantages:
• (1) Noisy
• (2) Low resolution
• (3) Limited fonts flexibility
• (4) Poor quality graphics output.

13. 13
“Daisy Wheel Printer”
• A daisy wheel printer is
basically an impact printer
consisting of a wheel and
attached extensions on
which molded metal
characters are mounted. A
daisy wheel printer
produces letter quality
print and it can’t produce
graphics output.

14. 14
How Daisy wheel printer
works?
• In a daisy wheel printer, a hammer presses
the wheel against a ribbon which in turn
makes an ink stain on the paper in the form
of a character mounted on the wheel
extensions.
• These printers are very noisy as there occur
great movement during the printing. Its
printing speed is also very slow ,i.e. less
than 90cps.

15. Ink Jet Printers
• How Do Ink Jet Printers Work?
• Performance

16. Ink Jet Printers –
How Do Ink Jet Printers Work?
• Ink jet printers are an example of non-impact
printers.
• The printer sprays tiny droplets of ink onto the paper.
• Ink jet printers are available for color and black-and-
white printing.

17. “Ink-Jet Printer”
• A standard Inkjet printer
has a resolution of 300dpi.

19. How Inkjet Printer works?
• (1) Print head having four ink
cartridges moves .
• (2) Software instructs where to apply
dots of ink, which color and what
quantity to use.
• (3) Electrical pulses are sent to the
resistors behind each nozzle.
• (4) Vapor bubbles of ink are formed
by resistors and the ink is forced to the
paper through nozzles.
• (5) A matrix of dots forms characters
and pictures.
Color cartridge showing inkjet nozzles.

20. Ink Jet Printers - Performance
Ink jet printers offer speeds of (2 – 4 pages per minute
ppm) and resolution (300 – 600 dots per inch dpi),
comparable to low-end laser printers.

21. Advantages/ Dis-advantages
Advantages:
(1) High resolution output.
(2) Energy efficient.
(3) Many options to select.
Dis-advantages:
(1) Expensive.
(2) Special paper required for higher resolution output.
(3) Time consuming in case of graphics printing.

22. Laser Printers
• How Do Laser Printers Work?
• Performance

24. Laser Printers –
How Do Laser Printers Work?
• Laser printers are non-impact printers.
• They use heat and pressure to bond particles of
toner to paper.
• Laser printers are available for color and black-and-
white printing.

25. How Laser printer Works?
• (1) Paper is fed and the drum rotates.
• (2) A laser beam conveys information from the
computer to a rotating mirror and thus an image is
created on the drum.
• (3)The charges on the drum are ionized and the
toner sticks to the drum.
• (4)Toner is transferred from drum to paper.
• (5)Heat is applied to fuse the toner on the paper.

27. Laser Printers - Performance
• Laser printers provide resolutions from 300 – 1200
dpi and higher.
• Black-and-white laser printers usually produce 4 –
16 ppm.
• Laser printers produce higher-quality print than
ink jet printers, but are more expensive.

28. 28
Thermal Printer
• Thermal printers are in-
expensive printers mostly
used in fax machines. The
Thermal printers are further
classified into two types.
• (1) Electro thermal
printers:
• (2) Thermal Wax printers: A fax machine using a thermal printer

29. 29
“Multi-function printer”
• A multi function printer
abbreviated as MFP is an all
purpose device that prints,
faxes, copies and scans. A
single multi function printer
can replace several bulky
devices. A multi function
printer is also known as
AIO. These printers use
inkjet technology and
provide high quality print
but at slow speed.

30. 30
“Plotter”
• A large scale printer which
is very accurate in
producing engineering
drawings and architectural
blueprints.
• Two types of plotters are
flatbed and drum.
• Flatbed plotters are
horizontally aligned while
drum plotters are vertically
positioned.

31. Snapshot Printers
• Snapshot printers are specialized, small-format
printers that print digital photographs.
• Snapshot printers are fairly slow, and can be more
expensive to operate

32. Snapshot printers

33. Other High-Quality Printers
Print shops and publishers use these printers to create
high-quality color images:
• Thermal-wax
• Dye-sublimation
• Fiery
• IRIS
• Plotters

34. Plotters use mechanical, ink jet, or thermal technology
to create large-format images for architectural or
engineering uses.

35. lesson Review
• List the three most commonly used types of printers.
• List the four criteria you should consider when
evaluating printers.
• Describe how a dot matrix printer creates an image
on a page.
• Explain the process by which a laser printer
operates.
• List five types of high-quality printing devices
commonly used in business.