Scanner – Input Unit/Devices

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Computer Scanner- Computer Fundamental- mLand India Technologies

A Scanner is an input device that capture/scans documents such as images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. This creates an electronic version of the document that can be viewed and edited on a computer.

Very high resolution scanners are used for scanning for high-resolution printing, but lower resolution scanners are adequate for capturing images for computer display. Most scanners are flatbed devices, which means they have a flat scanning surface.

What are the types of scanner?

The four common scanner types are:

+  Flatbed Scanners

+  Sheet-fed Scanners

+  Handheld Scanners

+  Drum Scanners

+  Flatbed Scanners

what is a flat bed scanner

Flatbed Scanner provides a flat, glass surface to hold a sheet of paper, book or other object for scanning. The scan head is moved under the glass. Flatbed Scanners often come with sheet feeders for scanning multiple sheets of paper rather than one at a time. Because of their large size capacity and ability to scan thick objects, flatbed scanners are more versatile than sheet-fed scanners.

Where is a flatbed scanner used?
 
A Flatbed Scanner is a device that you can use to scan in photographs and documents to your computer. Use it to convert any physical object into a digital copy which can then be emailed or uploaded to the Internet.
 
How does a flatbed scanner work?
 
A Flatbed Scanner is a shallow rectangular box with a glass top and a light source inside. You place a document on the glass and a mechanism moves the light progressively across the page while sensors capture the image. These scanners are useful for processing a relatively small number of pages at a time.

+  Sheet-fed Scanners

what is a Sheet-fed Scanners

Sheet-fed Scanner allows only paper to be scanned rather than books or other thick objects. It moves the paper across a stationary scan head. Contrast with flatbed scanner, handheld scanner and drum scanner.

Where is a Sheet-fed Scanner used?
 
Sheet-fed Scanners use digital imaging system that is specifically designed for scanning loose papers. These are more business-oriented scanners that are used in offices and workplaces as opposed to those used in libraries or archives.
 
How does a Sheet-fed Scanner work?
 
Sheet-fed Scanners are similar to flatbed scanners except the document is moved and the scan head is immobile. A sheetfed scanner looks a lot like a small portable printer. … At the center of the cylinder is a sensor that splits light bounced from the document into three beams.

+  Handheld Scanners

what is a Handheld Scanners

Handheld Scanners is moved by hand over the material being captured. Handheld Scanners are small and less expensive than their desktop counterparts but partially rely on the user’s dexterity to move the unit across the paper. It is as the name suggests, refers to an electronic device that performs the same tasks as that of a flatbed scanner. It is smaller, portable versions of their desktop cousins.

Where is a Handheld Scanners used?
 
It is used to scan physical documents into their digital forms that can be stored, edited, transferred and emailed digitally.
 
How does a Handheld Scanners work?
 
The heart of the Handheld Scanners is its detector array: a set of tiny light sensors formed into a line that takes up most of the scanner’s length. As it passes over a document, the scanner illuminates the page, and the sensors pick up the image or text as a set of points of light.

+  Drum Scanners

what is a Drum Scanner

Drum Scanners used to capture the highest resolution from an image and used by the publishing industry to capture incredibly detailed images. They use a technology called a photo-multiplier tube (PMT). In PMT, the document to be scanned is mounted on a glass cylinder. At the center of the cylinder is a sensor that splits light bounced from the document into three beams.

Photographs and transparencies are taped, clamped or fitted into a clear cylinder (drum) that is spun at speeds exceeding 1,000 RPM during the scanning operation. Contrast with flatbed scanner, sheet-fed scanner and handheld scanner.

Where is a Drum Scanner used?
 
It is used by the most of publishing industry to capture incredibly detailed images.
 
How does a Drum Scanner work?
 
Drum Scanners are used by the publishing industry to capture incredibly detailed images. They use a technology called a photomultiplier tube (PMT). In PMT, the document to be scanned is mounted on a glass cylinder. At the center of the cylinder is a sensor that splits light bounced from the document into three beams.

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