Brother International DCP 8040 Service Manual - Page 70

CHAPTER 3 THEORY OF OPERATION 2.2 Scanner Mechanism LF roller 1 ASSY LF roller 2 ASSY PF roller holder ASSY Front sensor actuator ASSY Eject roller ASSY ADF cover Guide shaft Top cover HP sensor CCD module Fig. 3-20 Scanner base Pulley ASSY Belt This scanner mechanism supports a dual scanning system. (1) If you set documents with their faces up on the document chute and start the scanning operation, the ADF motor rotates so that the document feed roller ASSY feeds those documents into the ADF unit, starting from the top sheet to the bottom, page by page. Each then document curves downwards and turns to the right so as to advance above the CCD unit, and then it is fed out to the document tray with the document ejection roller ASSY. This way, documents move above the CCD unit being kept in a stationary position. (2) If you open the document cover, put a sheet of document (or put a bound book opened) on the glass of the scanner top cover, close the document cover, and start the scanning operation, then the CCD drive mechanism will be driven. That is, the CCD motor rotates and its rotation will be transmitted via the gear train to the CCD drive belt. The CCD unit, which is supported and guide by the CCD rail, is secured to the CCD drive belt. Clockwise and counterclockwise rotations of the CCD motor move the CCD unit to the right and left, respectively. In this scanning system, the CCD unit moves horizontally beneath a document being kept in stationary position. The CCD unit contains a charge coupled device (CCD) image sensor. The cold-cathode florescent lamp illuminates a document and the reflected light of the scanned image data is transmitted via the mirrors into the lens which reduces the scanned data so as to form the image on the CCD. 3-14