Flatbed scanner

The major parts of a flatbed scanner are an optical system(which consists of a light beam, lens and mirrors), CCD (charge coupled device which senses light and gives an electrical output which is proportional to the intensity of light) and an electronic circuit (which converts the electric output to a set of bits). These bits are stored in a computer memory. The working of the scanner is like this: The document to be scanned is kept over the flat glass surface. Printed side should face the glass. Now a light source focuses light on the entire line as a thin beam and this line is termed as scan line. Light is allowed to reflect from the paper along the scan line. Light is not reflected for printed spots and light is reflected for prints. 300 CCDs which are arranged per inch gathers reflected light. Dark and white parts of the scan line are converted into 0s and 1s.