Canon Finisher-AB1 Service Manual page 59

2) When the trail edge of paper moves past PS6, the stack delivery roller and the paddle rotate in the direction
of the arrow, thereby pulling the paper back into the machine.
[1]Paper
[2]Stack delivery roller
[3]Sort delivery roller
[1]
[2]
F-3-23
[4]Assist stopper
[5]Transport belt
[6]Paddle
Chapter 3
[6]
[5]
PS6
[3]
3-25