Devices that output Hardcopy

Devices that output hard copy
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.
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.
(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.

1. Devices that Output
Hard Copy

2. 2
What is a printer?
Anexternalhardwaredeviceresponsible
fortakingcomputerdataandgeneratinga
hardcopyofthatdata.Printersareoneof
themostcommonlyusedperipheralsand
theyprinttextandstillimagesonthe
paper.

3. 3
Printers
Impact Printers
Non-Impact Printers
Daisy
wheel
Dot-
Matrix
InkjetThermalLaser

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 1
st
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.
Colorcartridgeshowinginkjetnozzles.

20. Ink Jet Printers -Performance
Inkjetprintersofferspeedsof(2–4pagesperminute
ppm)andresolution(300–600dotsperinchdpi),
comparabletolow-endlaserprinters.

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

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“Multi-function printer”
•Amultifunctionprinter
abbreviatedasMFPisanall
purposedevicethatprints,
faxes,copiesandscans.A
singlemultifunctionprinter
canreplaceseveralbulky
devices.Amultifunction
printerisalsoknownas
AIO.Theseprintersuse
inkjettechnologyand
providehighqualityprint
butatslowspeed.

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.