Scanning of documents is different from images, but use some techniques of the latter. Although the scanning of documents can be done in general purpose scanners, most of the times Scanners are dedicated to this special purpose, manufactured by Canon, Fujitsu and Kodak among others. Document scanners have higher feed tray to the normal of photocopiers and scanners.
Normally scanned at a resolution lower than normal scans of 150 dpi to 300 dpi, thus avoiding excessive file size.
Scanning is done in gray scale, although it is possible to do color. Most are capable of duplex scanning at maximum speed (20 to 150 pages per minute). The most sophisticated firmware to incorporate some ‘clean’ scanning eliminating accidental marks. Normally, the scanned data is compressed on the fly.
Most scanned documents are converted into editable files using OCR technology. Through ISIS and TWAIN drivers scan the document to TIFF format, scanned the pages to move to a word processor, which stores the file.
Scanning books involves additional technical difficulties. Some manufacturers have developed special scanners for this purpose including making use of ad hoc robots move pages.