Image Formation; Overview/Configuration; Overview - Canon FAX-L380S Series Service Manual

Chapter 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.

2.3 Image Formation

2.3.1 Overview/Configuration

2.3.1.1 Overview

/ / FAX-L390 / / / FAX-L380S
[1]
[8]
[7]
[6]
F-2-3
In response to a print command, the CPU turns on the main motor to drive the photosensitive drum, developing cylinder, primary charging roller, and transfer charg-
ing roller.
Thereafter, the machine uses the primary charging roller to charge the surface of the photosensitive drum to an even, negative potential and, at the same time, directs
the laser beam across the surface of the photosensitive drum. (The laser beam is modulated to according to the incoming video signals.)
The image thus formed on the photosensitive drum is a static, latent image; it is turned into a visible image by means of the toner from the developing cylinder. The
resulting toner image is then transferred to paper by the work of the transfer charging roller, and the paper is sent to the fixing assembly. The surface of the photo-
sensitive drum is cleaned by the cleaning blade so that it is free of residual toner; after cleaning, the primary charging roller once again charges the surface to an
2-2
[1] Laser driver PCB
[2] BD sensor
[3] Reflecting mirror
[4] Photosensitive drum
[2]
[4]
[5]
[1] Laser/scanner assembly
[2] Laser beam
[3] Blade
[4] Developing cylinder
T-2-2
[5] Imaging lends
[6] Scanner motor
[7] 4-facet mirror
[8] Cylindrical lens
[3]
T-2-3
[5] Photosensitive drum
[6] Transfer charging roller
[7] Primary charging roller
[8] Cleaning blade
0011-4685