Scanner is the input device which helps to convert a hard copy data into a soft copy data and send them to the computer. All scanners work on the same principle of reflectance or transmission. The image is placed before the carriage, consisting of a light source and sensor.
To direct light from the bulb to the sensors that read light values, CCD (Charge-coupled Device) scanners use prisms, lenses and other optical components. Contact Filecenter for scanners and to have everything organised online.
The amount of light reflected by or transmitted through the image and picked up by the sensor, is then converted to a voltage proportional to the light intensity – the brighter the part of the image, the more amount of light is reflected or transmitted, resulting in a higher voltage. The analogue-to-digital conversion (ADC) is a sensitive process, and one that is susceptible to electric interference and noise in the system. In order to protect against image degradation, an electrically isolated analogue-to-digital converter that processes data away from the main circuitry of the scanner is used. However, this introduces additional costs to the manufacturing process; so many low-end models include integrated analogue-to-digital converters that are built into the scanner’s primary circuit board.
The sensor component itself is implemented using one of the three different types of technology:
- PMT (Photo-Multiplier Tube): It is a technology inherited from the drum scanners of yesteryear.
- CCD (Charge-Coupled Device): It is the type of sensor used in desktop scanners.
- CIS (Contact Image Sensor): It is a newer technology which integrates scanning functions into fewer components, allowing scanners to be more compact in size.