Various Types of Display Devices and Printers

8/3/2019 Various Types of Display Devices and Printers

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VARIOUSTYPESOFDISPLAYDEVICESANDPRINTERS

Prepared by:

Anjali tailor(090070110051)

Khushboo patel(090070110035)

Khushboo desai(090070110037)


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ATTRIBUTES

High resolutionHigh brightnessLarge viewing angle

High writing speedLarge colour gamutHigh contrastLess weight and size

Low power consumptionLow cost


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VARIOUSDISPLAYS

Vacuum flourcent display (VFD)

Field emission display (FED)

Cathod ray tube (CRT)

Liquid crystal display (LCD)

Plasma display panel (PDP)

Electroluminiscent display (EL)

organic light emitting diode (OLED)Light emitting display(LED)


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FED

Field emission displays,electrons coming frommillions of tiny microtipspass through gates andlight up pixels on a screen.

This principle is similar tothat of cathode-ray tubesin television sets. The

difference: Instead of justone "gun" sprayingelectrons against theinside of the screens face,there are as many as 500

million of them (microtips).


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CATHOD

The cathode/backplateis a matrix of row andcolumn traces. Each

crossover lays thefoundation for anaddressablecathode emitters.

Each crossover has upto 4,500 emitters, 150nm in diameter. Thisemitter density assures

a high quality imagethrough manufacturingredundancy, and long-life through lowoperational stress.


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EMISSION

Emitters generateelectrons when asmall voltage isapplied to both row

(base layer) andcolumn (top layer).


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PIXELSFaceplate picture

elements (pixels) areformed by depositingand patterning a blackmatrix, standard red,green, and blue TV

phosphors and a thinaluminum layer toreflect colored lightforward to the viewer.


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METAL TIPS


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FED

Advantages and disadvantages:

MATRIX DISPLAY

LARGE VIEWING ANGLE

HIGH BRIGHTNESS,HIGH RESOLUTION

EXCELLENT COLOUR GAMUT

TECHNOLOGY NOT MATURE


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EL

The structure consists of two thin layers of dielectric withphosphor sandwitched between them. A thin Al layer on the topand thin ITO layer on the bottom completes EL.When voltage oforder of 200V is applied the resultant high electric field

(1MV/cm) tunnels electrons through dielectric on to phosphor.The high energy of electrons impact the colour centres to emitvisible light.

High brightness, high resolution,

Blue phosphor improvement required

High voltage switching

High purity materials

Small sizes

Expensive


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LCD

Most mature flat paneltechnology

Major share of FPD marketPoor intrinsic viewing angle

Requires backlight

Inefficient

SlowEffected by Temperature andsunlight


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PDP WORKING

Address electrodecauses gas tochange to plasmastate.

The plasma emits UVin discharge regionwhich impinges on

the phosphor

Reaction causes eachsubpixel to produce red,green, and blue light.


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PDP

Large Displays >32

High Resolution

High Brightness

Good ContrastGood Colour gamut

Large viewing angle

High Speed

Presently High Cost


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Not applicableNoteconomical

Potentialexists;

Cost?

Carbon

nanotubes

will

succeed.

Will replaceLCD

Mainly occupiedby AM LCD

Between 5 to 15

Games, automotive,

Internet applications,

Instrumentation

Not applicableNot

applicable

Potential

exists;Cost?

Will replace

LCD

Presently

occupied byPMSTN. AMLCD

will enter as

higher resolutions

and speed

requirements

increase

Between 2 and 5

Industrial, Internetappliances,

mobilephones,

cameras/ ca mcorders,

projectors

Not applicableNot

applicable

Potential

exists;

Cost?

Will replace

LCD

Presently

occupies PM STN

or LCOS

Less than 2

Pager, cell phones,

microdisplays

PROJECTIONPLASMAFEDOLEDLCDSIZE AND APPLICATION

TECHNOLOGY vs APPLICATION


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Prime contenderLess

attractive

than

projection

Above 50

HDTV,Video walls

Can penetrate into PDPOnly

choice

Remote

possibility

No

technologylimitations;

hopes are

high

Not applicableBetween 35 & 50

TV, HDTV, Largedisplays education

and advertisement

Not economicalHigh endof the size

eminently

suitable

DoubtfulLessexpensive

and better

performance

than LCD.

Tiling is

possible

Expensive for TV;Tiling by Rainbow

is a route

Between 20 & 35

TV

Potential

exists. But

technology

for large

sizes with

CNT?

Potential to

replace LCD

Sony already

demonstrate

d 15

Fully occupied by

AMLCD a:Si

Moving to p:Si

Between 15 to 20

Notebook PC and

Desktop

PROJECTIONPLASMAFEDOLEDLCDSIZE AND APPLICATION

TECHNOLOGY vs APPLICATION


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PRINTERS

A printer is a peripheraldevice that produces aphysical copy or hard copyof the computers output.


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IMPACT PRINTER

1) Impact Printer-In impact printers,characters areprinted by pressing a typeface against an inkedribbon, which makes a mark on the paper. Themostly common used impact printer is the Dot

Matrix Printer.

1) Non-Impact Printer - In non-impact printers,thereis no contact between the typeface and the paperwhile printing. They are much quieters than

impact printers because their printing heads donot strike the paper.Inkjet printer and Laser printerare the examples.


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CHARACTERISTICS Dot-matrix printers vary in two important

characteristics:

speed: Given in characters per second (cps), thespeed can vary from about 50 to over 500 cps.Most dot-matrix printers offer different speedsdepending on the quality of print desired.

print quality: Determined by the number of pins(the mechanisms that print the dots), it can varyfrom 9 to 24. The best dot-matrix printers (24 pins)can produce near letter-quality type, although youcan still see a difference if you look closely.

In addition to these characteristics, you should alsoconsider the noise factor. Comparedto laser and ink-jet printers, dot-matrix printers arenotorious for making a racket.


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PRINTING PROCESSIN DOT MATRIX PRINTER First the computer sends a series of ASCII codes to the

printer. The ASCII codes received by the printer are first stored in

the RAM buffer.

The bitmap table contained in the printer's ROM chip tells

the printer the pattern of dots it should use to produce therequired character shape represented by the ASCII code.

The printer processor takes the dot pattern informationfrom bitmap table and send the signals to the printer

head. The printer head contains 9, 18 or 24 pins aligned

vertically such that one end of each pin is connected toindividual electromagnet.

T fi th i t i i t th ibb d thi


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To fire the print pins against the ribbon and paper thiselectromagnet is energized due to which the moving pinstrikes the ribbon that is coated with ink.

After the pin fires, the electromagnet is de-energized whichmakes the spring pull the print pin back.

How it worksA print-head moves back-and-forth in front of

forms (paper) on which characters or graphic images aretransferred. The print-head contains numerous wires,typically from 9 to 24. Each wire is part of a solenoid-like unit.

A pulse applied to the solenoid creates a magnetic field whichforces the wire to move briefly forward then backward. As thewire moves forward, it presses against a print ribboncontaining ink. The impact transfers an ink dot to the paper.The paper is supported from behind by a plate.


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DEMO


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DOT MATRIX PRINT HEAD

Front view Side view

Print wires(e.g., 12)

One print wire


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DOT MATRIX IMPACT PRINTING

Printwire

Ribbon

Paper

Platen

Side view Side view Front view


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USES

Primarily two:

Any situation that requires multi-part forms

Small printers, such as

CalculatorsAdding machines

Point-of-sale terminals

D


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DOT-MATRIXPRINTERISSUES Print head -Print heads wear off after a while.

-The ink from the ribbon can clog the tiny pins that make

up the tiny pins-Pins can be bent

-Electromagnet can be damaged

Ribbon- Poor print quality can simply mean that the

ribbon needs to be replaced. Each printer get its ownribbon, the cartridge that the ribbon contained withinvaries from printer to printer thus they are notinterchangeable.

Overheating- Due to noisiness dot matrix printers are

often kept under a padded, sound proofed cover.-Less ventilation lead to overheating

Paper jams- Biggest problem paper jam

- If perforated sides can be ripped off they jam the printer.

(patience ,patience , patience is required to fix that .)


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ADVANTAGES

Dot matrix printers, like any impact printer, can print on multi-part stationery or make carbon-copies. Impact printers haveone of the lowest printing costs per page.

They are able to use continuous paper rather than requiringindividual sheets, making them useful for data logging.

They are good, reliable workhorses ideal for use in situationswhere printed content is more important than quality.

The ink ribbon also does not easily dry out, including both

the ribbon stored in the casing as well as the portion that isstretched in front of the print head; this unique propertyallows the dot-matrix printer to be used in environmentswhere printer duty can be rare, for instance, as with a FireAlarm Control Panel's output


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DISADVANTAGES

Impact printers create noise when the pins ortypeface strike the ribbon to the paper. Sounddampening enclosures may have to be used inquiet environments.

They can only print lower-resolution graphics, withlimited color performance, limited quality, and lowerspeeds compared to non-impact printers.


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DOT MATRIX PRINTER EXAMPLE - 1

Specifications

800 cps

400 lpm

6-part forms (max)


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DOT MATRIX PRINTER EXAMPLE - 2

Pacemaker 3410 by OKI Data, Inc.

Specifications Printhead wires: 9

Printhead life: 200 million characters

Print speed:

near letter quality: 105 cps

utility: 420 cps

high speed draft: 550 cps

Number of copies: 8

MTBF: 8000 hours @ 25% duty cycle,35% density


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LASERPRINTER

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LASERPRINTERCOMPONENTS

Toner cartridge

1. A hopper filled with toner. Toner is a fine powdercomposed of plastic, iron and carbon particles.

2. An EP drum covered with photosensitive coating thatholds a static charge until exposed to light.

3. A blade to remove used toner from the drum.

1. A corona charging assembly, which applies a static tothe drum after an image has been printed.

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TONERCARTRIDGE

32

L


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LASERPRINTERCOMPONENTSCONTD

Laser scanning assembly

Contains the following components:Laser - Shines on the drum and creates an electrostatic image

of whats printed.

Creates areas of negative charge on the positivelycharged drum.

Mirror--- Reflects the laser beam.

Lens --- Focuses the laser beam. Multiple lenses maybeused to focus the laser beam on the various areas of thedrum: the areas being closer to or farther away from the mirror

and laser beam. Power supplies

A high voltage power supply (HVPS) converts 120 volt, 60 HzAC current into high voltage electricity used by EP process. A

DC supply (DCPS) is used to power components that dontre uire hi h volta es.

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STEPSINTHELASERPRINTING

PROCESS

Charging or conditioning

The primary corona wire applies a negative charge ofapproximately -600volts to the EP drum.

Writing or exposing

The laser beams reduces the negative charge to about -100volts on the EP drum in the areas that become the image to beprinted.

Developing: Areas of the drum that were written to by thelaser attract toner.

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Transferring: A positive charge of about +600volts isapplied to the paper by transfer corona wire.

Fusing: Pressure and heat set the toner to the paper. A350 deg F fusing roller melts the toner, and squeezing

the paper through a set of rollers presses the toner intothe paper.

Cleaning and erasing: A rubber blade clears the excess

toner from the drum. Another corona wire removes thecharges from the drum.


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LASERPRINTPROCESS

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Corona wire packages


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UNPACKING

Toner is removed

Gently roll toner cartridge side to side

Install drum

Remove Styrofoam from toner area

Remove packing tape

Install toner cartridge37


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INSTALLINGALASERPRINTER

1. Connect the printer to the network or a computerusing the correct interface.

2. Plug it in.

3. Power it up.

4. Windows will likely recognize youve connected anew device and install drivers for it automatically.

5. If drivers arent installed automatically, you cando it manually using the materials that shippedwith the printer. 38


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PRINTERCONFIGURATIONOPTIONS Orientation Portrait or landscape

Collation How the individual pages within a multi-pagedocument are printed when you print more than one copy.Collated means entire copies of the document are printedtogether. Un-collated means that all the copies of page1 areprinted before all the copies of page 2, and so forth.

Copies:-- Number of copies to print Quality Options for draft , normal or high quality on some

printers. Others offer varying resolutions

Color:-- Specify full color or black and white print

Order:-- Some printers allow you to specify whether to print

from last page to first or first to last on multi-page print jobs. Switch print trays

Spool settings

Some configuration can be done through buttons on printeritself


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Various Types of Display Devices and Printers

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