Auto Density Sensing - Lexmark T650n Service Manual

4062-XXX

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.
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Diagnostic aids