Canon L120 Series, Service Manual

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Chapter 2
2-4
2.3 Image Formation
2.3.1 Overview/Configuration
2.3.1.1 Overview
0010-2240
FAX-L100 / FAX-L120
F-2-3
T-2-3
In response to a print command, the DCNT board turns on the main motor to drive the photosensitive drum, developing cylinder, primary charging roller,
and transfer charging 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 photosensitive 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 even, negative potential to prepare for the formation of a new static, latent image.
Drum Cover Shutter
If the surface of the photosensitive drum is exposed to strong light, it develops what is know as "photo memory," which can cause white spots or
black lines in images. To protect the drum against light, the machine is equipped with a drum cover shutter. The drum cover shutter must never be
opened unless doing so proves to be absolutely necessary.
[1] Laser/scanner assembly [5] Photosensitive drum
[2] Laser beam [6] Transfer charging roller
[3] Blade [7] Primary charging roller
[4] Developing cylinder [8] Cleaning blade
[1]
[4]
[5]
[6]
[7]
[8]
[2]
[3]