Canon Color imageRUNNER LBP5280, Service Manual, Page: 23 / 284

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Technical Reference > Laser Exposure System > Outline > Fault Detection
Technical Reference > Laser Exposure System > Outline > Fault Detection
Laser Exposure System
Outline
The laser scanner system forms the latent image on the photosensitive drum according to the
VIDEO signals sent from the main controller.
The main components of the laser scanner unit are the laser driver and the scanner motor
unit and are controlled by the signals sent from the DC controller.
The following figure shows the diagrammatic sketch of the laser scanner ass'y.
SCANNER MOT
OR
SPEED CONTROL
signal
VIDEO signal LASER CONTROL
signal
BD INPUT
signal
DC Controller
Main Controller
Photosensitive Drum
(Y)
Photosensitive Drum
(M)
Photosensitive Drum
(C)
Photosensitive Drum
(Bk)
BD Circuit
Laser Driver
Polygon Mirror
Scaner Motor Unit
F-2-2
Controlling the Laser Scanner Motor
■
Fault Detection
1. Scanner motor failure
• The scanner motor does not reach a specified rotation within a specified period after
starting-up the laser scanner motor.
• The rotation of the scanner motor is out of specified range for a specified period during
scanner motor drive.
2. BD failure
• The BD interval is detected at out of a specified value during a print operation.