Scanners are devices that convert objects, photos and documents into digital images. Most commonly the scanner is connected to a computer and the digital image, converted by the scanner, is transferred into computer. The image may or may not be edited in the computer and then it may be emailed, faxed or simply be kept as a record according to what the owner wants to do with them.

Specifications

Various specifications of scanners are there. These are mainly image sensor type, color or monochromatic scanning, optical resolution and speed. A scanner with a high quality image sensor will offer more shades, better color fidelity and sharper image. Color scanners offer better resembling images.

Optical resolution is the true measure of how well a scanner can see a document. Measured in ‘dpi’, optical resolution between 200 and 400 offers standard quality, while that being higher than 400 dpi produces an excellent image. Lastly there is one of the most important factors about the image size that decides the image width of a scanner.

Other specifications can include energy star ratings and software and file formats offered and even weight.

Types

Scanners may come in a variety of types. The most common types of scanners are Drum type scanners, Flatbed type scanners, Film type scanners and Hand type scanners. There are also black-n-white and color scanners available.

As indicated by the names, the former is able to produce only black and white colors while the later will produce a color image. The first age color scanners were realized only by three colors: red, green and blue (the RGB system). There are also CCD (charged couple device) and CIS (contact image sensor) scanners.

These are categories based on image sensors. There are large or small format scanners, too. Large format color scanners are certainly the best of the lot. Historically the first invented scanners were drum type and the most popular is flatbed type.

Despite all these, there remains another viewpoint of differentiating between scanner types. The types are: automatic feed scanners and sheet fed scanners.

Automatic vs. Sheet fed scanners

In an automatic feed scanner the document is scanned efficiently even if they are not put in the scanning tray by manual technique; one after another, as opposed to sheet fed ones. An automatic scanner detects whether a document page is great or small, color or monochromatic and they don’t even need to be supplied with arranged documents. The latest quality automatic large format color scanner works far more efficiently when compared to sheet fed ones, where pages need to insert one after one.

Large format color scanners are truly amazing. Spending around $20000-$25000 for one may result in lifelong ease, comfort and increased work efficiency and speed.

==================================