Auto Image Density (Ads) - Ricoh D009 Service Manual

Image Processing
There is SP code to create a test pattern which can be used as a diagnostic tool to
troubleshoot problems in the SBU:
SP4907-001 SBU Pattern - Test Pattern
To print the pattern:
Select the pattern to print.
Touch "Copy Window" then press the Start key twice.

6.5.3 AUTO IMAGE DENSITY (ADS)

The copier scans the auto image density detection area [A]. This corresponds to a narrow
strip at one end of the main scan line, as shown in the diagram. As the scanner scans down
the page, the IPU on the BICU detects the peak white level for each scan line, within this
narrow strip only. From this peak white level, the IPU determines the reference value for A/D
conversion for the scan line. Then, the IPU sends the reference value to the A/D controller
on the SBU.
When an original with a gray background is scanned, the density of the gray area is the peak
white level density. Therefore, the original background will not appear on copies. Because
peak level data is taken for each scan line, ADS corrects for any changes in background
density down the page.
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.
D009/D011/D012/D013 6-18 SM