Canon GP200 Service Manual page 103

The GP215/GP200's AE may be 'priority on
speed' (default) or 'priority on image quality'.
(Here, the discussions are on 'priority on image
quality'; for 'priority on speed', see p. 3-32.)
In 'priority on image quality', the density cor-
rection curve is varied according to the type of
original.
In 'priority on image quality', the scanner is
moved forward to suit the size of the detected
original, thereby executing full scanning for mea-
suring the density of the entire original.
This way, the density of the background and
the density of the image are measured to classify
the original into any of the following three types:
q Background Type Original
Originals which are white or light in density
carrying text.
w Reversal Type Original
Originals which are colored or light in density
carrying light text or reversed text.
e Other Originals
Originals with little variation in density (e.g.,
photos).
Copy density
Density of orignal
AE Table for Background Type
Figure 3-340
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following three AE tables is selected to generate a
correction table to suit the original for density cor-
rection.
in service mode ( * 3 * ); see p. 3-205
RDF, AE is initiated for each original which is
picked up.
to check the density of all originals for the selec-
tion of an AE table.
Copy density
Density of orignal
AE Table for Reversal Type
Figure 3-341
CANON GP215/200 REV.0 JULY 1996 PRINTED IN JAPAN (IMPRIME AU JAPON)
3. OPERATIONS AND TIMING
Depending on the type of original, one of the
You may adjust the "priority on image" function
When AE is executed using the ADF or the
In page separation, a signal AE scan is used
2mm
Figure 3-343 Points of AE Measurement
Copy density
Density of orignal
AE Table for Other Type
Figure 3-342
2mm
3–49