CH- 5 MODERN ELECTRONIC MACHINES Marks: 10 (15)
Copier Machine (Xerox):
A photocopier is a machine that makes paper copies of documents and other visual images quickly and cheaply.
Most current photocopiers use a technology called xerography, a dry process that uses electrostatic charges on a light-sensitive photoreceptor to first attract and then transfer toner particles (a powder) onto paper in the form of an image.
Heat, pressure or a combination of both is then used to fuse the toner onto the paper. Xerographic office photocopying was introduced by Xerox in 1959.
Working:
Charging: cylindrical drum is electrostatically charged by a high voltage wire called a corona wire or a charge roller. The drum has a coating of a photoconductive material. A photoconductor is a semiconductor that becomes conductive when exposed to light.
Exposure: A bright lamp illuminates the original document, and the white areas of the original document reflect the light onto the surface of the photoconductive drum. The areas of the drum that are exposed to light become conductive and therefore discharge to the ground. The area of the drum not exposed to light (those areas that correspond to black portions of the original document) remains negatively charged.
Developing: The toner is positively charged. When it is applied to the drum to develop the image, it is attracted and sticks to the areas that are negatively charged (black areas), just as paper sticks to a balloon with a static charge.
Transfer: The resulting toner image on the surface of the drum is transferred from the drum onto a piece of paper with a higher negative charge than the drum.
Fusing: The toner is melted and bonded to the paper by heat and pressure rollers.
Procedure and controls of photocopying machine:
Turn the switch on the photocopier. Wait for the machine to warm up.
Lift the copy counter and place the document on the glass plate of the copier.
Once the documents are in the right position, select the desired number of copies with the help of keypad on the machine.
Select the paper size option
Press the large button machine (usually green), which is the copy button in most photocopiers. Its pages are copied successfully.
Advantages of photocopier:
Many copies of document can be made.
It copies the document accurately and fastly.
Copy of document is cheap compared to printer.
It can enlarge or reduce the size of document.
It can store the document in digital format for mailing.
It can copy on both side of paper.
Operating system is easy and simple.
Scanner:
A scanner is a device that is used for producing an exact digital image of a photo, text written in paper, or even an object.
This digital image can be saved as a file to computer and can be used to alter/enhance the image or apply it to the web.
The most commonly used scanner is the flatbed scanner, in which you keep the object on top of the glass window.
The scanned output will be obtained in computer. The image and text are obtained exactly through the process of optical character recognition [OCR].
Scanners have become an important part of the home office over the last few years. Scanner technology is everywhere and used in many ways.
Types of scanners:
Flatbed scanners: These are also called desktop scanners, are the most versatile and commonly used scanners. These are similar to photocopiers. The picture to be scanned is placed over glass. The lower beam scans the picture and creates binary file.
Sheet-fed scanners: These are similar to flatbed scanners except the document is moved and the scan head is immobile. A sheet-fed scanner looks a lot like a small portable printer.
Handheld scanners: These scanners are moved over the image slowly by holding in hand. The laser rays generated inside the scanner scan the image and convert it into a binary file. These are small in size and scan resolution is low quality.
Drum scanners: These are used by the publishing industry to capture incredibly detailed images. They use a technology called a photomultiplier tube (PMT). Scann
Scanning procedure:
Clean the surface of the scanning bed with a soft cloth and streak-free glass cleaner.
Open the lid and place the document face-down on the scanning bed. Then close the lid carefully.
Launch the scanning software that came with your scanner.
Select “Document” as the scan type.
Select an output format for the scanned document, usually an image type such as PDF.
Choose a resolution, if prompted, that produces a high quality file such as 300dpi. While selecting a higher dpi will create a larger-sized file.
Click the “Scan” button. When the scanning process completes, click “Save.” Enter a file name for the document and select a destination folder, such as My Documents. Click the “Save” button.
Advantages of Scanner:
Scanners provide high quality resolution for colour and black & white document.
It creates digital copies of documents, photos and files in computer which can be used for emailing purpose.
Easy to use.
Scanners are highly reliable
Applications of scanner:
Flat bed scanners are used in scanning documents, photos or book cover.
Hand held scanners are used in big malls for preparing bills.
Scanners are used in Biomedical research like CT scan and MRI scan.
Scanners are in ATM machine to scan name account number from ATM card.
Lamination machine (Laminator):
The primary purpose of laminating with such a machine is to protect printed documents or images.
Lamination is the technique of manufacturing a material in many layers, so that the composite material achieves improved strength, stability, good insulation and appearance.
A laminate is a permanently assembled object by heat, pressure and adhesives. Laminated documents are water resistant, are easy to clean and do not damage easily.
Laminating pouch consists of a hard plastic outer shell with a softer plastic lining.
The lining liquefies with heat. It is very similar in makeup to a hot glue stick.
As this glue softens, it sticks to the object that has been placed inside the pouch. Once heat is removed, the glue cools and solidifies.
The cooled glue is clear and transparent.
A laminator essentially provides the heat and the pressure needed to make the pouch look good. As the pouch warms up, pressure is applied to the pouch via silicon rollers.
Uses:
To laminate paper back book covers. Magazine covers, posters, cards etc.
In restaurants to mention the items and price list.
Laminations are used for preparing educational and training materials.
Laminations are used for preparing membership card and business cards.
I-Card Making Machine:
Identity cards used for identification of school and college students.
Many people carry gym membership cards which contain a barcode that you hold up to a card reader before entering the facility.
Some corporate offices require employees to carry proximity cards to gain access to office buildings, or smart cards to log onto company computers and networks.
Working/procedure:
Desktop photo ID printers print directly onto plastic PVC cards with a photo ID system.
They typically use a dye sublimation process or thermal resin transfer process to adhere the color and other over laminates to the card. T
he resulting ID card is much more attractive and durable. It is easy to encode information on the card with a magnetic stripe or bar code.
Many dye-sub printers will print directly the ID cards into other systems for access control, time-and-attendance, and other tracking.
Emergency Light:
Emergency light is an integral part of household electronics nowadays.
We all know Emergency light is used during the power failure to light up the home.
As it is used during the power failure, it should last long.
Hence bright white LEDs are used in emergency light, because they produce more light and consume less power.
Circuit diagram:
Working:
This circuit consists of step down transformer, bridge rectifier and filter capacitor of 1000 uF. This part gives DC voltage.
Voltage regulator 7808 has been used to Regulate the DC voltage. It gives 8V DC.
The second part of the emergency light circuit consists of relay, array of LEDs and 6V-4.5Ah rechargeable battery.
Normally when there is no power failure, the coil of Relay remains energized.
In this situation LEDs are disconnected from the rechargeable battery and remains OFF.
Also battery is getting charge through the power supply from the transformer.
A diode D5 is used to prevent the battery from flowing back.
Block diagram of emergency light:
AC mains supply is fed to the step down transformer, and then it is rectified to charge the battery through a sensor relay.
A lamp is connected to battery circuit through the relay.
When AC supply fails the relay connects the battery to the lamp circuit through the normally closed contact and lamp will glow.
FAX (Facsimile Machine):
FAX machine is used to transmit electronic image of document. FAX is a modern technique of transmitting and reproducing documents, maps, pictures and photographs over the phone line. FAX is originated from the word FACSIMILE.
Uses: FAX is commonly used in business activities, newspaper documentation, government and military organization for sending information in the form of written or printed paper.
Principle: Most of the concepts used in TV are applicable to the facsimile machines. In TV the signals are in analog form while FAX uses signals in digital form. This digital signal provides advantages like data compression, error correction etc.
Block diagram:
Working:
FAX machine is a combination of copier/scanner, telephone system and printer. It is a ‘transreciever’.
It scans the documents and transmits them over the phone line to remote fax machine, which receives document in synchronization and reproduces it using a printing systems.
The steps involved in sending documents are scanning, compression and transmission.
The data converted into the set of points represented by the bit mapped electrical signal, with the help of scanner. Then it is given to the compressor where page size is reduced and finally it is given to the transmitter.
Questions
Marks wise Questions: 1M (2), 3M (1), 4M (1), 6M(1)
1. Fill in the blanks-
Photo copier uses --------- particles to produce document.
(i) semiconductor (ii) light sensitive (iii) toner
---------machine is used to produce bills in big malls.
(i) Photocopier (ii) scanner (iii) Laminator
----------increases durability of document.
(i) Scanning (ii) Photocopying (iii) Lamination
---------process is used for lamination of document.
(i) Heat and pressure (ii) Heat and light (iii) Light
In ---------- machine audio tone is used.
(i) scanner (ii) FAX (iii0 photo copier
In FAX, ---------are used for scanning process.
(i)CCD (charged coupled devices) (ii) Raster (iii) Line
. ------------ machine is used to transmit electronic image of document.
(i) Xerox (ii) FAX (iii) EPABX
Most of photocopiers use a technology called xerography.
A scanner converts the images or documents on paper to binary data.
Laminating type ID card making machine uses cut and paste method.
CCD is a light sensitive semiconductor device that converts light into electrical signal.
4. Answer the following-
Explain principle of working of a photocopier machine.
State advantages of photocopiers.
Write the procedure of photocopying (Xerox).
State the different controls of photocopying machine.
Explain working of photocopier.
What is scanner? Explain it.
Write the procedure of scanning.
State and explain types of scanners.
State advantages and applications of scanners.
What is purpose of lamination machine?
Explain working of lamination machine.
State uses of lamination machine.
Write a not on I-card making machine.
Explain use of emergency light.
With circuit diagram explain working of emergency light.
With block diagram explain working of emergency light.
What is FAX machine? State its use and principle.
With block diagram explain working of FAX machine.
