Canon LaserBase MF3220 Series, Service Manual

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Chapter 2
2-2
2.2 Laser Exposure
2.2.1 Overview/Configuration
2.2.1.1 Overview
0012-0873
F-2-2
T-2-2
The machine's laser scanner assembly consists of the laser driver and the scanner motor, which are driven by signals coming from the engine controller.
The laser driver serves to turn on the laser diode according to the laser control signal and video signals from the engine controller.
The laser beam moves thorough the collimator less and the cylindrical lens to reach the 4-facet mirror rotating at a specific speed.
The leaser beam reflected by the 4-facet mirror moves through the imaging lens arranged in front of the 4-facet mirror and the reflecting mirror to reach and focus
on the photosensitive drum.
When the 4-facet mirror rotates at a specific speed, the laser beam scans the photosensitive drum in keeping with the mirror rotation, thus drawing static images on
the photosensitive drum.
MEMO:
BD Fault
The machine identifies a BD fault if it does not detect the /BDI signal within 0.1 sec after the scanner motor is forced to accelerate. It also detects a BD fault
if it does not detect a specific interval of /BDI signals for 2 sec continuously after the scanner motor has reached a specific revolution (number of rotations).
Scanner Fault
If the machine does not detect the /BDI signal 1.4 sc after it has stopped forcing the scanner motor to accelerate, it extends the period of detection by 120 sec;
if it still does not detect a specific interval of /BDI signals, it identifies a scanner fault.
BD Error
The machine identifies a BD error if it does not detect the /BDI signal at a specific interval while the /BDI signal is being generated. It, however, does not
identify a BD error under the following condition:
-the door is identified as being open within 0.2 sec after detection of a BD error.
-a BD fault or a scanner fault is detected after a BD error has been identified.
The laser/scanner unit contains parts that cannot be adjusted in the field. Do not attempt to disassemble the laser/scanner unit.
[1] Laser driver PCB [5] Imaging lends
[2] BD sensor [6] Scanner motor
[3] Reflecting mirror [7] 4-facet mirror
[4] Photosensitive drum [8] Cylindrical lens
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