Canon iR4570 Series Service Manual page 511

Finisher present
2. 1st Side of a Double-Sided Print
When the double-sided print feed sensor (PS17) goes on, the machine will assume that printing on the 1st side has
been completed, thereby increasing the count.
Target of
Condition
delivery
Tray 2
Tray 3
Sensor
No. 2 delivery sensor (PS1A)
No. 3 delivery sensor (PS5)
Delivery sensor of the finisher
Chapter 10
10-5