HP LaserJet Enterprise M552 - Laser;scanner failure detection; Safety

Laser/scanner failure detection
The DC controller determines an optical unit failure and noties the formatter of the error status when any of
the following occurs:
●
Laser/scanner motor startup failure: The scanner motor does not reach a specied rotation frequency
within a specied period of time from when the laser/scanner starts up.
●
Laser/scanner motor abnormal rotation: The laser/scanner motor does not reach a specied rotational
frequency within a specied period of time during a print operation.
Safety
The laser/scanner assembly has a mechanical laser shutter. For the safety of users and service technicians,
the laser shutter interrupts the optical path of the laser/scanner assembly when the top door is opened
(SW101).
28 Chapter 1 Theory of operation ENWW