Lexmark CX310dn, Service Manual

Page: 361 / 394

The redrive bubble sensor, located before the fuser exit rollers in the paper path, senses the bubble in the paper as it
exits the fuser. It then adjusts the fuser motor speed as necessary to avoid jams and smearing on the trailing edge of
the paper.
Duplexing
Printers with duplex support use a secondary paper path to print on the second side of a sheet of paper. The duplexing
process is summarized as follows:
After the first side of the paper is printed and the trailing edge of the paper clears the fuser exit sensor, the fuser motor
engages to reverse the paper direction and feed it into the duplex unit. The pick motor also reverses. The pick motor
drives the duplex aligner rolls (A), which push the media down to the bottom turnaround in the paper tray and gate
aligner (B).
Note: While the sheet is being transported through the duplex unit, it is the only piece of paper being processed by
the print engine. A user should not attempt to insert a piece of paper into the manual paper feed while a duplex job
is being processed. This would cause a paper jam error.
When the trailing edge of the media clears the fuser, the fuser engine rotates forward to prepare the fuser for the page
traveling though the duplex unit.
As the media reaches the gate aligner, a sensor (S1) is triggered, indicating the presence of the leading edge.
When the S1 sensor is triggered, the paper continues to the (S2) sensor. When the S2 signal is detected, the speed of
the pick motor is adjusted to accommodate the speed of the transfer belt, ensuring the proper registration of the image
on the media. The paper travels to the transfer module (C), and the second image is transferred to the reverse side of
the media.
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Appendix C: Theory of operation
361