Chapter 5 Other Functions; Document Detection Function; Double Feed Detection Function; Skew Detection Function - Canon DR-9080C Service Manual

Chapter 5 Other Functions
The scanner is equipped with a document detection function which stops a
document from feeding if it detects that the document is not being fed correctly.

Double Feed Detection Function

The scanner automatically detects two pages that have been fed at the same time
(double feed) and displays an error code that means "Double feed detection" when
scanning documents continuously.
The following shows the double feed detection methods. Select the detection
method on the ISIS/TWAIN driver's settings screen.
G Detect by Length
The scanner uses the length of the first page of the document as the standard,
and any pages that exceed this length by 50 mm or more are considered to be
a double feed.
G Detect by Ultrasonic
The scanner detects the gap between the two pages that have been fed
together and considers it to be a double feed.
G The ultrasonic double feed detection works when a document overlaps by more than
50 mm.
Note
G You can combine the detection methods noted above.
G The error code, which is displayed when a double feed is detected, varies depending
on the combination of detection methods. For more information, see "When an Error
Code Is Displayed," on page 75.
G Double feed detection in the count only mode is set in user mode settings. For more
information, see "Setting in the User Mode," on page 60.

Skew Detection Function

If a long document is skewed, it may rip when it rubs against the feeding path or
the sides of the feeding path. The scanner is equipped with a "skew detection
function" that can detect skewed documents when they touch the edges of the
feeding path. When a skewed document is detected, an error code is displayed
and the scanner stops scanning.
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Document Detection
Function