Lexmark X925 Service Manual page 175

Duplexing
If a page is two-sided, a signal is sent to the Printer Controller Board once the trailing edge of the paper passes
the Fuser Exit Sensor. The leading edge of the paper partially feeds from the Exit Rolls and then reverses
direction and feeds into the Duplex Unit. This method of re-feed is called a "Peek-a-boo".
The Duplex Entry Rollers pass the paper down to the Duplex Transport Rollers along the right side of the printer.
Once the paper reaches the bottom, the Duplex Exit/MPF detection lever senses the leading edge of the media
at the Duplex Exit Roller and it engages the Duplex re-feed clutch to transport the sheet of paper into the EP
paper path.
Exit roll
Paper
Paper exit sensor
Fuser exit roll
MPF Registration roller
Std Registration roller
(Delivery roll)
Paper
Note: Once the media reaches the Duplex Exit/MPF detection lever, it shares the same paper path as the
MPF.
Paper
Registration
Sensor
Duplex exit roll
Duplex entry roller
Timing belt
Duplex clutch
Timing belt
Transfer roll
Paper
Lower duplex transport roll
Timing belt
Duplex / MPF sensor actuator
Diagnostic aids
7541-03x
3-43