Lexmark MS911 Service Manual page 609

The sensor (duplex pass through 2) detects the position of the paper. The motor (transport) drives the lower duplex
transport roller and duplex exit roller.
The paper then travels to the registration section to print on the other side. For more information, see
section" on page 603.
# Part
1 Motor (transport)
2 Sensor (duplex pass through 2)
3 Lower duplex transport roller
4 Duplex exit roller
5 Registration section
Appendix C: Theory of operation
609
4021
"Registration