HP Color LaserJet Enterprise CM4540 Service Manual - Page 125

Optical assembly operation Figure 1-55 Optical assembly operation Document Reflector Glass CCD Lens Scanner lamp Inverter circuit CPU Scanner controller Second mirror First mirror Third mirror Carriage home position sensor The optical assembly contains the lamp, mirrors, lens, and charge-coupled device (CCD). As the optical assembly moves across the original, the lens focuses the reflected image onto the CCD. The optical assembly home position is detected by the carriage home position sensor. During document feeder copying, the optical assembly remains near the home position and the product moves the paper across the document feeder glass strip. Image data path Figure 1-56 Image data path The product transfers the analog data produced by the CCD/image sensor to the analog front end (AFE), which is a PCA that converts this information to digital form. The digital data exits the scanner assembly and then passes through the scan control board (SCB) to the copy processor board (CPB), which is located on the formatter. ENWW Document feeder/scanner assembly 73