Scanner and ADF functions and operation Scanner Functions The scanner uses a light source, a color-separation method, and a Charge Coupled Device array (CCD) to collect optical information about the document and transform that into an image file. The scanner consists of: a lamp (cold fluorescent bulb) five mirrors and a lens a CCD Figure 11. Optical diagram of scanner The scanner lamp illuminates a small strip of the document (called the raster line ). The light is directed via the mirrors through the lens to the CCD. The CCD senses and records the light, creating an analog representation of the raster line.
If using the ADF, the document then advances in the ADF to the next raster line. If using the flatbed, the scanner module advances to the next raster line. This advancing and collection process continues up to the end of the sheet. 80 Chapter 4 - Operational overview EN Scanner Glass CCFL Lamp 600 ppi CCD Lens