1. BY-
HEENA ABBASI
BCA
SECTION - D

2. CONTENTS---
 Introduction to scanners.
 Types of scanners –
I. Flatbed scanner.
II. Hand-held scanner.
III. Optical mark reader.
 Limitation of image scanners.
 Introduction to plotters.
 Types of plotters-
I. Drum plotter.
II. Flatbed plotter.

4. Scanners are input devices
which allow data entry from
source document directly.

5.  It is an input device, translates paper
document into electronic format, as an input
to a computer.
 Input can be type, text, pictures, even
handwritten material also.
 Useful for preserving paper documents, a
document stored in computer does not
deteriorate in quality with age.
 It can be printed or displayed whenever
required. We can also alter and manipulate
the stored images.

6.  Eliminate manual entry of data , thus
improves data accuracy.
 Automatic entry of data with their use
improves data accuracy , increase timeliness
of information processed.
 Demand high quality source document ,
rejects-poorly typed documents or strikeover
documents or documents having erasures.
 Form design and ink specification is more
critical with the use of these devices as
compare to keyboard for data entry.

7. Types of scanner---
FLATBED SCANNER
HAND-HELD SCANNER

8.  It is like a copier machine.
 Consist of a box having a
glass plate on its top, lid
that covers a glass plate.
 Activated glass plate moves
horizontally from one end
to another.
 After scanning one line,
light beam moves up a little
to scan other line , process
continues till the scanning
finishes.
 Takes 20 seconds to scan a
document of 21*28 cm in
size.
 They are costly as compare
to hand-held scanner.
 User can hold them in hand
conveniently.
 It has a case of light
emitting diodes incased in a
small case.
 For scanning, user drags it
slowly from one end to
other of a document when
its light is on.
 User must drag it slowly and
smoothly for the correct
conversion of document to
its equivalent bit map.
 User use them when they
have less number of
documents.
 They are cheaper than
flatbed scanner.

9.  If a document stored in the computer as an
image instead of text , than it is not possible
to do any word processing.
 Storage space required for storing the
document as an image is much more than
that required for storing a text document.

10.  It is a scanner , which recognize pre-
specified type of mark made by pencil or
pen.
 The technique used by OMR devices for
recognition of marks on document involves–:
Focusing a light beam on the
document and detecting the reflected light
pattern from the marks.

12.  A plotter is an ideal output device for
architects, city planners, engineers' and
others who need to generate high precision,
hard copy, graphic output of varying size.

13. Two types of
plotters are-
Drum plotter
Flatbed plotter

14.  It consist of a drum, 1 or
more penholders mounted
perpendicular to the drum’s
surface.
 Drum rotates both clockwise
and anti-clockwise to
produce vertical motion.
 The pens move right to left
and left to right to produce
horizontal motion.
 Graph plotting software
controls the movement of
drum and pens.
 User can produce multi
colored designs by mounting
pens having ink in different
colors in different folders.

15.  Consist of a rectangular
flatbed table, 1 or more
penholder mounted
perpendicular to the table’s
surface.
 A graph plotting software is
also there.
 Plots design on paper sheet
spread and fix over the
table.
 Paper doesn’t move and pen
holder provide all necessary
motion to draw designs.
 Plot size restricted by the
area some are as small as A4
size and some are very large
to make designs of bed ,
ships , aircraft etc.
 Some plotters also etch on
plastic and metal plates , for
that the pen has a sharp-
edged needle.