HP LaserJet Enterprise M552 - Document feeder e-duplex operation; Deskew operation

Document feeder e-duplex operation
Following is the basic sequence of operation for a document feeder simplex job.
NOTE: For an e-duplex copy job, the background scan operation begins immediately after the simplex
sequence of operation ends.
1. The feed motor continues to drive the paper until the leading edge activates the prescan back-side
sensor. The printer rmware registers the position of the leading edge of the paper.
2. The feed motor continues to rotate to drive the leading edge of the paper through the preset distance
from prescan back-side sensor to the back-side background selector scan zone. The back-side
background scan module begins scanning and retrieval of the data.
3. The prescan back-side sensor deactivates when the trailing edge of the paper passes it. The printer
rmware registers the trailing edge of the paper position.
4. The feed motor continues to rotate to drive the trailing edge of the paper edge past the back-side
background selector scan zone.
5. The feed motor continues to rotate and ejects the trailing edge of the paper into the output bin.
6. One of the following occurs:
●
If the copy job is complete, the ADF paper present sensor deactivates. The feed motor reverses
rotation to raise the pick roller.
●
If the copy job is not complete, the ADF paper present sensor is active. The printer rmware
detects additional pages in the input tray and the process repeats.
Deskew operation
Sliding side guides on the input tray make sure that the paper stack is correctly aligned at the center of the
input tray when paper is loaded in the tray. The correct position of the loaded paper is parallel with the
direction of travel into the document feeder paper path
The document feeder further reduces paper skew due to improper loading of paper in the input tray by
buckling the paper to create a paper buer.
The document feeder aligns the leading edge of the paper parallel with the deskew drive rollers before it is
driven further into the document feeder paper path.
74 Chapter 1 Theory of operation ENWW