Feed Error Detection - Canon imageFORMULA DR-G2140 Service Manual

CHAPTER 2 FUNCTION & OPERATION

4. Feed Error Detection

 Jam Detection
Document jams are detected by the reg-
istration sensors. The types of the document
jams are described as follows.
1) Pickup Delay Jam (Pickup Error)
The leading edge of the document was not
detected by the registration sensors within
the specified time after the machine starts
scanning.
2) Early Reach Jam
The leading edge of the following docu-
ment was detected after the trailing edge
of the document was detected by the reg-
istration sensors before the document has
been fed for a specified length.
3) Residual Jam
The trailing edge of the document was not
detected even though the document has
been fed for the maximum specified length
after the leading edge of the document
was detected by the registration sensors.
4) Fast Feed Jam
The trailing edge of the document was de-
tected after the leading edge of the docu-
ment was detected by the registration sen-
sors before the document has been fed for
the minimum specified length.
5) Non-removal Jam
The machine starts scanning while the
document is detected by the registration
sensors and still remains inside this ma-
chine.
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 Double Feed Detection
There are 2 double feed detection meth-
ods: the document length detection by the
registration sensors and the document over-
lapping detection by the ultrasonic sensor.
The registration sensors uses the first
document length of the scanned batch as a
reference to detect the document length. The
35 mm or more difference from the standard
is interpreted as a double feed.
The ultrasonic drive sensor transmits the
ultrasonic and the ultrasonic receive sensor
receives the ultrasonic signal to gain a spe-
cific signal level. When overlapping docu-
ments are fed, the signal level is different from
when properly feeding a single document.
This machine interprets this difference as a
double feed.
Note: The double feed detection by ultrasonic
may not work if the document overlap-
ping width is 50 mm or less. Further, the
machine does not execute the double
feed detection for the area of 15 mm
from the leading and trailing edges of
the document.
Figure 2-304
CANON DR-G2140/G2110/G2090 FIRST EDITION