2. Printer-
• A Printer is an electromechanical device which
converts the text and graphical documents from
electronic form to the physical form and gives
output.
3. A. Based on to the Printing Speed
Serial printers-
• Prints the characters one by one.
• Speed is expressed in characters per second
• Can reach a few hundreds of characters per second.
Line printers-
• Prints all the characters in a line simultaneously.
• Speed is expressed in lines per minute.
• Can reach several thousands of lines per minute.
Page printers-
• Contains buffer memories for one or more pages.
• Printing is done by preparing the image to be printed for
an entire page in memory, after which the paper is
advanced continuously during printing.
• Their speed may reach 50,000 lines per minute.
CLASSIFICATION OF PRINTERS
4. B. Based on to the Printing Quality
• There are three quality levels of the printed documents:
Low or draft quality-
• Saves ink.
• Allow the user to see what the print job would look like
before printing the final copy.
Medium or near-letter quality-
• Able to print with the quality typically expected from a
business typewriter such as an ibm selectric.
• Letters are clearer and less jagged than a low quality
printer.
High or letter-quality-
• High quality output
in printed from a printer linked to a word processor.
• Better than above both in quality of printing.
5. C . BASED ON THE OPERATING PRINCIPLE
There are two important categories:
Impact printers –
• Work by striking 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.
• Advantage: allow to make several copies
simultaneously.
• Drawback: relatively slow and are noisy.
6. 2. Non-impact printers-
• Have fewer moving parts
• No direct physical contact between the printing
mechanism and the paper.
• Examples of non-impact printers are thermal,
inkjet printers.
• Advantages: high speed, high quality of the
printed text or image, and low level of noise,
• Disadvantage: cannot create several copies
simultaneously.
7. Inkjet Introduction
Inkjet printing:
• Type of computer printing that recreates a digital
image by propelling droplets of ink onto paper, plastic,
or other substrates.
• Most commonly used type of printer.
• Ranges from small inexpensive consumer models to very
large professional machines that can cost tens of
thousands of dollars.
• Came into existence in about late 1980’s.
• These have become the replacement printer for the serial
dot matrix in the home cause of two main reasons:
Low Price
More Color capabilities
8. Inkjet Introduction
• An Inkjet printer is any printer that places extremely
small droplets of ink onto paper to create an image.
• It produces characters by squirting a precisely
controlled amount of ink onto the paper.
• Dots are extremely small usually 50-60 microns in
diameter (Human Hair approx 70 microns).
• Dots are placed very precisely on the paper in a
pattern up to 1440 x 720 dots per inch(dpi).
• Dots can be of different colors combined together to
create photo-quality images.
9. Inside an INKJET PRINTER
Parts of typical Inkjet Printer
include:
Print Head Assembly:
Print Head: The core of an inkjet
printer, the print head contains
a series of nozzles that are used
to spray drops of ink.
Interface Ports: USB port or
Serial Port like Small Computer
System Interface(SCSI) port are
used as Interface Ports.
10. Inside an inkjet printer
Paper Feed Assembly:
Paper Tray/Feeder: Most Inkjet Printers
have a tray that you load the paper into.
The Feeder typically snaps open at an
angle on the back of the printer,
allowing you to place paper in it.
Power Supply: Earlier Printers often
had an external transformer, most
printers sold today use a standard
power supply that is incorporated into
printer itself.
11. Inside an inkjet printer
Ink Cartridge:
There are variety of cartridges depending on
the manufacturer of the printer. Eg. Multi
color in one cartridge or Single color in
one cartridge.
Control Circuitry: The mechanical
operation of the printer is controlled by a
small circuit board containing a
Microprocessor and Memory.
12. Inkjet printer Working:
A typical inkjet receives control info
from your printer driver/PC.
Either way, rollers advance a page
from your paper tray (1) under a
sliding print head/cartridge
assembly (2).
Then, the print head stepper
motor (3) kicks in, drawing the
assembly on a sliding rod (4) to its
starting position, usually via
a belt(5).
The head's microscopic nozzles (8)
—anywhere from dozens to literally
thousands—are outlets for incredibly
tiny ink chambers (9), which are
fed by the cartridge's reservoirs.
13. Inkjet printer Working:
Microscopic droplets (10),
measured in millionths of a
millionth of a liter, fired
through the nozzles.
Instead, most inkjets use
"thermal" technology in which
a tiny resistor (11) in an ink
chamber is pulsed, as needed,
with intense current,
superheating the ink and
vaporizing part of the droplet.
The result: Terrific pressure
blasts it out the nozzle and
onto your page.
14. Features of INKJET PRINTER:
• They can print from two to four pages per minute.
• Resolution is about 360 dots per inch, therefore
better printing quality is achieved.
• The operating cost is quite low, the only part that
needs replacement is Ink Cartridge.
• Color inkjet printers have four ink nozzles with
colors Cyan ,Magenta ,Yellow and Black, because it
is possible to combine these colors to create any
color in visible spectrum.
15. • DEPENDING ON THE DROP GENERATION
METHOD:
• Three types of inkjet printers are used:
1. Continuous jet- The droplet generation head is
continuously supplied with ink under pressure by a
pump.
2. Intermittent jet-These printers use an ink charged
electrostatically, which is supplied at a low pressure.
3. Drops-on-demand-This method is the most used on
common inkjet printers. The droplets are generated
individually with the help of an electric pulse that
determines deformation of the nozzles’ chambers or
heating of the ink.
16. Heat vs Vibration
There are several technologies that are used for building inkjet
printers. Most common are:
• Thermal: Most inkjets use thermal technology, whereby
heat is used to fire ink onto the paper. Droplet generation is
achieved by very rapidly heating up the ink, with a few hundreds of
Celcius per μs.
17. • Piezoelectric: uses a Piezo crystal at the rear of
the ink reservoir. This is rather like a loudspeaker cone
that flexes when an electric current flows through it. So
whenever a dot is required, a current is applied to the
Piezo element which then flexes and, in so doing, forces
a drop of ink out of the nozzle.
18. Advantages:
1. Initial Cost
Ink-Jet printers are one of the lowest cost
products on the market.
2. Quality
Today you can create images or documents with
high quality by Inkjet printers.
3. Space
Compare to laser printers, the ink jet printers
have suitable size to put on the desk on your office
or a small room in your home
4. Time
Different from laser printer, the inkjet printer do
not require time to heat the machine system
before print.
19. Disadvantages:
1. Cartridge Cost
You can buy a cheap inkjet printer first but with the
replacement of the cartridges in a long time, the cartridge
cost can exceed the machine cost.
2. Speed
You can only use ink-jet printer to create little volumes of
documents only because inkjet printer is slower than laser
one.
3. Moisture
After creating images or documents, we must wait until
those dry. Sometimes it can delay our delivery process.
4. Ink
The replacement of cartridges causes some unexpected
problems the printers like cartridges clogged with ink.
