Generally three types of scanners are available in the market, (1) Drum Scanners, (2) Flatbed Scanners and (3) Hand Scanners.
(1)Drum Scanners: Drum Scanners use photomultiplier tubes (PMT) as the substitute to Charged coupled device or CCD that are found in flatbed scanners. The original copy is mounted to the acrylic cylinder. The scanner drum rotating at high speed passes the original that is being scanned. The incident occurs before a precision optics. These precision optics deliver image information to PMT. Most of the scanners work with three matched PMTs that can read three colors of red blue and green lights respectively. Light reflecting from the object splits into red, green and blue light beams in the optical bench of scanner.
(2)Flatbed Scanners: Flatbed scanner constitutes of a glass pane, under which a bright light comes from. This light can be cold cathode fluorescent or xenon. At the time of scanning this light illuminates the glass pane. Color scanners consist of 3 arrays of red, green and blue filters.
(3)Hand Scanners: The name itself suggests that this device is operated manually. These are dragged on the surface of the image which has to be scanned. But this act needs absolute mastery in the art; otherwise, it can result into uneven scrolling of the machine and eventually bad quality scanning.
Here are suggestions from thaydeserveit for people who bare bewildered at the fact that which scanner should be bought and gifted to one's near and dear ones.
Color USB Business Card Scanner (Visiting card) with software can be gifted to busy executives or agents who have to make visiting cards in emergency. Such a gift will save time for a busy executive when he/she is on short of visiting cards, but badly in need of those.
Agroxs-8250 Barcode Scanner is specially designed for scanning papers related to shipping and necessary in factories. The company boasts of the product reading PDF codes, Code 16K properly and without unmistakably. The USP of the scanner is its long range scanning of 200mm.
HP Scan Jet 2400 Digital Flatbed Scanner is a one-touch scanning and color copying device with 1200 dpi optical resolution and 48-bit color. Apart from photos sketches and graphic drawings are printed with the same perfection. The device yields true-to-life photos that resemble real life objects.