Canon MF4500 Series, Service Manual

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Technical Overview > Document Exposure/Feeder System > Document Feeder System > Overview
Technical Overview > Document Exposure/Feeder System > Document Feeder System > Overview
Document Feeder System
■ Overview
● SADF
The Single-side Auto Document Feeder (SADF) mounted onto this host machine is dedicated
to stream-reading.
1 motor (SADF motor) is engaged in pickup/feeding/delivery.
At the start of copy/fax/scan, the SADF motor is driven by the drive command from the SCNT
to pickup/feed the originals set face up on the original tray one by one in order from the top.
The original is scanned by the contact sensor when moving through the copyboard glass, and
then delivered face down to the original delivery assembly.
SCNT
J12
1
2
3
4
A0
A0*
B0
B0*
SADF Motor
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Within the SADF pickup assembly is the stop [1] for the purpose of preventing the push-in of
original, which descends/ascends in conjunction with the gear [2] on the end of the pickup
roller shaft.
SADF
Motor
[1]
[2]
• When the originals are moving through the machine
( )
By the CW drive of the SADF motor, which is transmitted to the pickup roller via the gear/
spring clutch and results in positive rotation of the pickup roller, original pickup is performed.
At this point, the gear on the pickup roller shaft rotates positively as well, ascending the stop.
When the originals are moving through the equipment, the stop is kept ascended.
• At detection of original being set and after delivery of the last sheet of the original
( )
The gear on the pickup roller shaft rotates negatively by the CCW drive of the SADF motor,
descending the stop. At the CCW drive, the drive is not transmitted to the pickup roller via the
spring clutch, leaving the pickup roller stopped.
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