RICOH STINGER-C1
Instrukcja Serwisowa

IMAGE PROCESSING

17 May, 1999

2.2.3 AUTO IMAGE DENSITY (ADS)
[A]

A250D004.WMF

In the SBU
ADS prevents the background of an original from appearing on copies. The copier scans the image density area [A] detected by the ADS sensoras shown in the diagram. This corresponds to a few mm at one end of the main scan line. As the scanner scans down the page, the IPU on the BICU detects the peak white level for each scan line. The IPU determines the reference value for the A/D conversion for a particular scan line using the peak white level for that scan line. Then, the IPU sends the reference value to the reference controller circuit on the SBU. When scanning an original with a gray background, the density of the gray area is the peak white level density. Therefore, the original background will not appear on copies. ADS corrects for any changes in background density down the page, because peak level data is taken for each scan line. As with previous digital copiers, the user can select manual image density when selecting auto image density mode and the machine will use both settings when processing the original.

In the IPU
After the SBU process, the IPU board removes more background by adjusting the white level. If the user selects a �Service Mode� original type with the user tools, these two ADS process can be either enabled or disabled (SP4-936, SP4-937), and the amount of white level change can be adjusted (SP4-938).

2-8