How Does a Paper Scanner Work?


How Does a Paper Scanner WorkThere are a few different types of scanners to choose from when you are thinking of purchasing one.

How the scanner works will depend on how what kind of scanner you purchase.

Types of Document Scanners:

Flatbed Scanner

ScannerA scanner that provides a flat, glass surface to hold pages of paper, books, and other objects for scanning.

The scan head is moved under the glass across the page. Sheet feeders are usually optionally available that allow ,multiple sheets to be fed automatically.

Handheld Scanners

a scanner that is moved by hand over the material being captured. Handheld scanners are small and less expensive than their desktop counter tops but partially rely on the user’s dexterity to move the unit across the paper. Trays are available that keep the scanner moving in a straight line.

Drum Scanners

A type of scanner used to capture the highest resolution from an image. 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. A light source that focuses on one pixel is beamed onto the drum and moves down the drum a line at a time.

Sheet-Fed Scanners

Flatbed ScannerThis scanner that allows only paper to be scanned rather than books or other thick objects. It moves the paper across a stationary scan head.

How A Paper Scanner Works

Here are the steps the occur in a flat bed scanner. The process may differentiate slightly from these steps if you use one of the varying scanners listed above, however, this gives a good idea of how the documents are scanned onto the computer.

  1. The document is places on the glass plate of a scanner and the cover is closed. The inside of the cover in most scanners is flat white or black. The cover provides a uniform background that the scanner software can use as a reference point for determining the size of the document being scanned.
  2. A lamp is used to illuminate the document.
  3. The entire mechanism (mirrors, lens, filter and CCD array) make up the scan head. The scan head is moved slowly across the document by a belt that is attached to a stepper motor. The scan head is attached to a stabilizer bar to ensure that there is no wobble or deviation in the pass. Pass means that the scan head has completed a single complete scan of the document.
  4. The image of the document is reflected by an angled mirror to another mirror. In some scanners, there are only two mirrors while others use a three mirror approach. Each mirror is slightly curved to focus the image it reflects onto a smaller surface.
  5. The last mirror reflects the image onto a lens. The lens focuses the image through a filter on the CCD array.
  6. The filter and lens arrangement vary based on the scanner. Some scanners use a three pass scanning method. Each pass uses a different color filter (red, green or blue) between the lens and CCD array. After the three passes are completed, the scanner software assembles the three filtered images into a single full-color image.

Do you need Scanning Services?  Record Nations can help!

If you have documents that you would like scanned but aren’t ready to invest in a scanner just yet, we can help. Record Nations has a network of scanning experts who use the most reliable, state-of-the-art techniques to scan your data and get your business working paperless as quick as possible.

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To get started, fill out the form to the right, or give us a call at (866) 385-3706Within minutes of receiving your request, you will have free quotes from experts in your area that can help you with your project.