Canon iR4570 Series Service Manual page 385

1. Increase in Speed for Pickup
The speed is 1.5 times as high as the process speed (in the cassette of manual feed, decelerates to about 0.6).
2. Increase in Speed for Reversal
The speed is 2 times as high as the process speed.
F-8-25
Chapter 8
[2]
[1]
8-29