Canon iR4570 Series Service Manual page 382

Chapter 8
[1]
F-8-22
[1]Pickup acceleration interval
The machine accelerates the speed to about 1.5 times as high as its process speed.
(No acceleration occurs if the pickup is from the manual feeder. In the case of the 1s side of a sheet picked up from
cassette 1, the movement will be about twice as fast.)
In the Presence of the Finisher-S1
8-26