Canon Duplex Unit-A1 - Page 24

Chapter 2
2-6
F-2-6
4) When the predetermined time lapses after the trailing edge of the paper is detected by the duplex paper sensor 1 (SR1002), the reversal motor stops (M1002).
5) When the predetermined time lapses after the duplex paper sensor detects the leading edge of the fist paper is detected by the duplex paper sensor 2 (SR1003),
the feeder motor stops. The first paper stops at the standby point (about 90 mm downstream from the duplex paper sensor 2).
SR1002
SR1003