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					                     College Of Information technology




                        PREPARED BY:
                     ABDALLAH AL-FALOJY

                               (120090221)


                           Under supervised:

               Miss Rasha Ragheb Attallah




                                      First Semester

                                       2009_2010




                              +
Introduction To Business Processing                      1
     - Define the Light Pen


An input device that used a light sensitive detector to select objects on a display
screen . A light pen is similar to a mouse except that with a light pen you can
move the pointer and select objects on the display by directly pointing to the
objects the pen

- Write about the CPU
Central Processing Unit (CPU) :
carries out the instructions of the program. It contains circuits that perform arithmetic and
logical operations.
Data is transferred from primary storage to the CPU with the results sent back to primary
storage.

- In Chapter 4 we talk about several type of the printers , make a search on the Internet about
the image of this type

_ Impact printer:

Refers to a class of printers that work by banging a head or needle against an ink ribbon to
make a mark on the paper. This includes dot-matrix printers, daisy-wheel printers, and line
printers. In contrast, laser and ink-jet printers are nonimpact printers. The distinction is
important because impact printers tend to be considerably noisier than nonimpact printers but
are useful for multipart forms such as invoices.




 -

 -     non-impact printer:

A type of printer that does not operate by striking a head against a ribbon. Examples of
nonimpact printers include laser and ink-jet printers. The term nonimpact is important
primarily in that it distinguishes quiet printers from noisy (impact) printers




  - Serial printer:
A printer that prints one character at a time in the sequence in which they appear in
the line of text.


        Hydraulic Engineering Project   2009                                                    2
All serial printers have an arrangement in which a print head moves parallel to the
paper and along the line to be printer.




_ Page printer
Printer that prints one full page of text or graphics at a time, ejects that page and then feeds in
the next page to be printed. These types of printers are now the most commonly used printers
with the popularity of laser printer and ink jet printers.




    Line printer:
A high-speed printer capable of printing an entire line at one time. A fast line printer can print as many
as 3,000 lines per minute. The disadvantages of line printers are that they cannot print graphics, the
print quality is low, and they are very noisy.




      Hydraulic Engineering Project      2009                                                           3
Laser peinters
A type of printer that utilizes a laser beam to produce an image on a drum. The light of the laser alters
the electrical charge on the drum wherever it hits. The drum is then rolled through a reservoir of toner,
which is picked up by the charged portions of the drum. Finally, the toner is transferred to the paper
through a combination of heat and pressure. This is also the way copy machines work.




    Dot matrix
    Creates characters by striking pins against an ink ribbon. Each pin makes a dot, and




    combinations of dots form characters and illustrations.


    Letter-quality printers:
Refers to print that has the same quality as that produced by a typewriter. Computer printers are
sometimes divided into two classes: those that produce letter-quality type, such as laser, ink-jet, and
daisy-wheel printers; and those that do not, including most dot-matrix printers.




Draft-quality printers:

Describes print whose quality is less than near letter quality. Most 9-pin dot-matrix printers produce draft-
quality print.




Ink-jet or bubble-jet




       Hydraulic Engineering Project         2009                                                               4
A type of ink-jet printer developed by Canon. The principal difference between bubble-jet printers and
other ink-jet printers is that bubble-jet printers use special heating elements to prepare the ink whereas
ink-jet printers uses piezoelectric crystals.




      Hydraulic Engineering Project      2009                                                            5

				
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