Canon DADF-M1 Service Manual - page 46
Chapter 2
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2.4 Document Pickup/Separation
2.4.1 Basic Sequence of Operation
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When the Start key is pressed with an original on the original tray, the machine executes the following sequence of operation to pickup up the original:
a. Picking Up the Original
When the pickup motor (M1) rotates in reverse and the pickup clutch (CL1) goes on, the pickup roller unit moves down to start pickup operation. The separation
plate and the separation pad are used to prevent multiple feeding of originals. (After the 2nd original, the pickup unit remains in down position.)
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b. Aching the Original
When the original has been moved for a specific number of pulses after the registration sensor has gone on, the original is caused to arch at the No. 1 registration
roller so that it becomes free of any skew.
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c. Sheet-to-Sheet Distance
While the original is between the No. 1 registration roller and the No. 2 registration roller, its movement is accelerated so that there will be a sheet-to-sheet distance
at the time it reaches the No. 2 registration roller for reading. The normal rotation maximum speed of the pickup motor is 750 mm/sec; it decelerates to reading
speed at a point 23 mm in front of the No. 2 registration roller to move the original to the No. 2 registration roller.
d. Moving the Original
The pickup clutch goes off and the pickup motor rotates in normal direction to move the original. The lock motor is driven for locking before the leading edge of
the original reaches the platen upstream roller (thereby preventing the shock otherwise occurring when the trailing edge of the original leaves the roller). When the
original reaches the point of deceleration before reading, the machine checks whether the READY signal is on, in which case it will move the original ahead to the
point of reading; if the signal is off, the machine keeps the original in wait for reading. (In the case of the 1st original, the machine moves it as far as the read sensor
at 650 mm/sec.)
M1
CL1
Original
Stopper
Pickup roller
Unit
M1
CL1
Original
Pickup roller
Unit
Separation plate
Separation pad
CL1
M1
Arching
No. 1 registration roller
Registration sensor