Ricoh SP 200 Specifications download pdf (Page 26)

2.3 AUTO IMAGE DENSITY (ADS)

This mode prevents the background of an original from appearing on copies.

The copier scans the auto image density detection area [A] as 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 data to the reference

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.

[A]

Sub scan direction

A193D004.wmf

1 August 1996 IMAGE PROCESSING

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Ricoh SP 200 Specifications Page 26