Document Scanning At Adf; Document Scanning At Platen - Lexmark MX81 series Service Manual

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Auto density sensing
The image density sensor assembly uses a reflection type sensor that detects a pre-placed toner patch and image on
the photoconductor (drum) and outputs pulses when the central line of the patch image aligns with the central line of
the detector. The sensor outputs pulses at the timing the patch image passes the sensor. Therefore observing changes
of intervals at which pulses are output leads to toner density detection.

Document scanning at ADF

The document scanning section of this machine consists of a scanner that reads a single-sheet document placed on the
platen glass and a document feeder that can transport a multiple-sheet document for one or two-sided scanning.

Document scanning at platen

Appendix C: Theory of operation
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