Delay Jams - Canon imageCLASS MF4890dw Service Manual

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Technical Overview > Pickup And Feeding System > Detecting Jams > Delay Jams

■ Delay Jams

● Delivery Delay Jam
There are 3 types of delivery delay jam detections as follows:
A. When there is no preceding paper
B. When there is a preceding paper 1
In the case of narrow paper interval with the preceding paper
C. When there is a preceding paper 2
In the case of wide paper interval with the preceding paper
A. When there is no preceding paper
If the delivery sensor (PS701)detects no paper from 700 (1400) ms to 1235 (2470) ms after
detection by the TOP sensor (PS751), a delivery delay jam is determined.
OFF
Paper Lead Edge
Sensor
ON
OFF
Fixing Delivery
Sensor
ON
700(1400)
1235(2470)
Note :
"700 (1400) ms" was calculated from the distance of 104.8 mm from the leading edge
of the TOP sensor (PS751) to the fixing nip. "1235 (2470) ms" was calculated from
the distance of 135.5 mm from the leading edge of the TOP sensor (PS751) to that of
the delivery sensor (PS701) and the delivery delay jam margin of 50 mm. Since the
distance from the fixing nip to the delivery sensor (PS701) is 30.7 mm, the length of
wrapping from the leading edge will be 80.7 mm. Since one lap of the film is 18.2π (57.2)
mm, the length of wrapping is more than one lap. Considering paper looping, sensor
accuracy, and thick-paper delivery, however, the value cannot be made smaller.
2 Technical Overview > Pickup And Feeding System > Detecting Jams > Delay Jams
paper detection
period
Jam
F-2-34
B. When there is a preceding paper 1
OFF
Paper Lead Edge
Sensor
ON
OFF
Fixing Delivery
Sensor
ON
700(1400)
1165(2400)
When there is preceding paper at the delivery sensor (PS701) 700 (1400) ms after paper
detection by the TOP sensor (PS751) and the delivery sensor (PS701) does not detect the
no-paper status until 1165 (2400) ms later, a delivery delay jam is determined.
C. When there is a preceding paper 2
OFF
Paper Lead Edge
Sensor
ON
OFF
Fixing Delivery
Sensor
ON
700(1400)
1165(2400)
When there is preceding paper at the delivery sensor (PS701) 700 (1400) ms after paper
detection by the TOP sensor (PS751) and the delivery sensor (PS701) detects the no-
paper status by 1165 (2400) ms later, a delivery delay jam is determined only if the delivery
sensor (PS701) does not detect paper in the period from 70 ms after no paper detection by
the delivery sensor (PS701) until 1235 (2470) ms after paper detection by the TOP sensor
(PS751).
Note :
"1165 (2400) ms" is the balance of subtracting a margin of 70 ms from the delivery
delay jam detection end time of 1235 (2470) ms by considering chattering from the
trailing edge of the preceding paper is at the delivery sensor until the leading edge of
the next paper is detected.
2-28
paper Absence
detection
period
Jam
F-2-35
paper detection
70
period
70
Jam
F-2-36
2-28