Canon DADF-AV1, Service Manual

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Document Reversing
Basic Operation
There are two types of document reversal operation: one that is performed from the top to the reverse side of the document and
the other that is performed from the reverse side to the top of the document.
Since the basic operation methods are identical, only the reversal operation performed from the reverse side to the top is discussed
below.
■ Top side pickup
The Read motor (M2) drives the Lead roller 1 (upper) and the Platen roller to scan the surface of a document on stream reading.
After completion of scanning, Read motor (M2) drives the Lead roller 2 (upper) and the Upper delivery reversal roller to feed a
document to the reverse point.
Upper delivery reversal roller
Platen roller
Read roller 2(Upper)
Read roller 1
(Upper)
M2 M2
■ Reversal/Feed 1
After the trailing edge of a fed document passes the Delivery reversal sensor (SR3), the Read motor (M2) stops.
Thus a document stops at the reverse point. The Read motor (M2) drives in reverse direction to feed a document to the Registration
roller and then it stops. After that, the Release solenoid (SL1) turns on to release the Lower delivery reversal roller.
Delivery reversal sensor(SR3)
SL1
M2
SL1
M2
■ Reversal/Feed 2
The Pickup motor (M1) drives the Lower registration roller through the Registration clutch (CL2) to feed a document to the Read
wait point.
Thus, the document is reversed. After a document is picked up again, turn OFF the Release solenoid (SL1) to pressurize at the
same time that reverse side reading is complete. After that, each operation is performed such as re-reverse, feeding and
delivering.
2. Technical Explanation
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