Canon DR-2580C Service Manual page 51

If a document skews when you select auto-
matic size detection, but do not select skew
correction, parts of leading and trailing edges
of the image will be missing.
Figure 2-518
Note: In case that part of circumference of
document is dark or brightness level is
not appropriately set, this function may
not successfully work. This may also
happen when the skew correction or
black frame removal described later is
performed.
COPYRIGHT © 2005 CANON ELECTRONICS INC.
7) Skew Correction (Deskew)
CANON DR-2580C FIRST EDITION APR. 2005
CHAPTER 2 FUNCTION & OPERATION
If the skew correction is selected, the size
of document read is broadened by 10 mm
compared with the user-specified size.
The skew is detected based on the data
read to compensate the skew.
The image data is then restored to the
user-specified image size.
Maximum outside frame
Angle
ABC
ABC
Figure 2-519
2-25