Page 15 - TP_iPlus_V2.1_Class7
P. 15
• Monitor: Monitor is a standard output device. It is also known as Visual Display Unit (VDU) or
Screen. Monitor is used for interactive processing i.e., the data being fed is displayed on the
screen. It resembles a television. The images that you see on the monitor are
made up of tiny dots called pixels. The clarity of the images depends on the
number of dots/pixels per inch on the screen. The maximum number of dots per
inch (dpi) will give you more clarity and a better display.
Nowadays, monitors with Light Emitting Diode (LED) screens have become very popular
because of the clarity of the images and the slim shape of the monitor.
• Printer: Printer is a common output device which is used for the purpose of printing documents.
Printer generates a hard copy of data or information. Printers are categorised as impact or
non-impact depending on their printing mechanism. Impact printers print the contents by
striking the printer head or needles, on an ink ribbon which rolls through the cartridge to
make mark on the paper. Non-impact printers create an image on paper by spraying ink on
the paper. Some of the common printers are:
◦ Dot Matrix Printer
Dot matrix printer is the most commonly used impact printer. It is also
known as the ‘Wire Matrix’ printer. In a dot matrix printer, the printer
head contains a matrix of pins. In a dot matrix printer, characters are
printed by forming dots. The print head, which moves back and forth across the page,
strikes the pins against the ribbon to create dots at each character position.
A print head of a Dot matrix printer contains 9 or 24 pins. Dot matrix printer is cheaper and
has low printing cost than other printers. The width of a dot matrix printer can be 80 or 132
or 136 columns. Dot matrix printer can print upto 100 to 300 characters in a second. The
resolution of the printing ranges from 150 to 300 dots per inch (dpi).
◦ Inkjet Printer
Inkjet Printer is an example of a non-impact printer. It produces a high quality
print outputs by spraying drops of ink (which is stored in coloured and black
cartridges). This printer has a print head which contains the cartridge that
has several tiny holes through which the ink is sprayed on the paper.
An inkjet printer can print upto 2 to 10 pages per minute. These printers are more expensive
than dot matrix printers, but they offer better print quality and operate at a modern pace.
Inkjet printer prints photo quality image with resolution of 400 dpi to 4000 dpi (dots per inch).
◦ Laser Printer
Laser printer prints the contents by laser technology. It is fast in operation
as it operates in similar manner as photocopy machines. The laser beam
makes shadow of the images with the help of toner and transfers them
on paper.
It is also known as ‘Page Printer’ because it actually stores the content of the page in memory
before printing it. It can print between 5 and 300 pages per minute, with a resolution
ranging from 600 dpi to 2400 dpi.
13
Computer—Hardware Components

