A scanner is a computer input device that utilizes a light beam to scan codes, text, or images directly into a computer system. Bar-code scanners are extensively used at retail point-of-sale terminals. A handheld scanner or bar-code pen is moved across the code, or the code itself is moved across a scanner built into a checkout counter, and the computer immediately processes the data. This allows the computer to identify the product, determine its price, and input that information into the cash register.
Optical scanners are also found in fax machines and are used to input graphic material into personal computers. Flatbed scanners have a lifting top, requiring manual placement of materials for scanning. Sheetfed scanners, on the other hand, can handle multiple loose pages that are passed over the scanner by rollers.