Canon iR C1020 Series Service Manual page 194

Chapter 9
5) The paper is transported to the delivery tray by the delivery roller.
Since the duplexing/delivery flapper is turned down at this point, the feed path toward the duplexing feed assembly is closed.
Whether or not the paper has been delivered to the delivery tray is detected by the delivery sensor (SR715).
When the paper in the delivery tray reaches the full level, the delivery paper full-level flag comes into contact with the paper, and the full level is detected by
the delivery paper full-level sensor (SR713).
9-10
Delivery roller Delivery full-level flag
M11
SR713
SR715
F-9-11