HP Color 9850mfp Service Manual - Page 84

SCANNER 1.2.6 AE control hp Color 9850mfp The CCD sensor installed on the A/D converter board (ADB) reads the copy density during the AE scan, it performs the process responsive to the read density on the overall control board (OACB), and then it selects the most favorable γ correction curve. The CPU on the image processing board (IPB) performs the selection. A. AE/ACS sampling range The AE/ACS sampling range is identical to the read range in both the scanner mode and the DF mode. [1] II UNIT EXPLANATION [3] [1] 10mm [2] [1] [1] [1] [2] AE/ACS sampling range [3] Paper feed direction 1.2.7 Image processing A. AOC (automatic offset control) With the circuit in the CCD sensor, AOC automatically adjusts the analog offset voltage from the sensor to be the lower limit of the A/D converter. B. AGC (automatic gain control) AGC automatically controls the level of the analog amplification of the CCD sensor output at the shading white correction to be the higher limit for the A/D converter. C. Shading correction (1) Types of the shading correction • White correction • Black correction (2) Execution timing • At the main switch (SW2) ON • At the start of scan job 2-10