Canon iPF600 series Service Manual page 105

The pick-up timing of the paper fed to the rear of the printer is controlled by the paper detection sensor.
b) Manual feed (from rear)
The paper loaded in the paper tray provided at the rear of the printer is fed onto the platen for printing.
This method of feeding paper can be used only when an acceptable media type is selected from the Manual Feed menu in the user mode. The pick-up timing of the
paper loaded in the rear paper tray according to the message shown on the operation panel is controlled by the paper detection sensor.
paper detection sensor
F-2-35
paper detection sensor
F-2-36
Chapter 2
2-39