Document Scanning At Adf - Lexmark 7462 series Service Manual

Auto density sensing
The cleaning blade removes any toner that remains on the drum after the transfer process. The toner that the
cleaning blade removes is collected inside the sealed PC cartridge.
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
twosided scanning.
Document scanning at platen
Shown below is the operational overview of document scanning at the platen.
The scanner LED assembly travels to read the document.
The exposure lamp is installed on the scanner LED assembly. As the scanner LED assembly travels, the
document on the platen glass is scanned and exposed with the exposure lamp.
# Part
1 Sensor shield assembly
2 Sensor (toner density)
Appendix C: Theory of operation
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