Canon LASER SHOT LBP-1210, Service Manual

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V. IMAGE FORMATION SYSTEM
A. Outline
The image formation system is the central hub of the printer. This system consists of the car-
tridge, transfer charging roller, fixing unit, etc.
When a print command is sent from the interface controller, the engine controller drives the
main motor to rotate the photosensitive drum, developing cylinder, primary charging roller,
transfer charging roller, and pressure roller.
The primary charging roller uniformly applies a negative charge to the photosensitive drum
surface. At the same time, the laser beam, modulated by the VIDEO (VDO, /VDO) signals, is
exposed onto the drum surface to form a latent image on the drum.
The latent image formed on the photosensitive drum is developed into a visible image by the
toner on the developing cylinder, and then transferred onto paper by the transfer charging roller.
The transferred toner is changed to a permanent image by heat and pressure in the fixing unit.
Meanwhile, residual toner on the photosensitive drum’s surface is scraped off by the cleaning
blade. Then, the potential on the drum is made uniform by the primary charging roller in prepa-
ration for the next latent image.
Figure 2-5-1
CHAPTER 2
2 - 35
FB
PR1
TRS
DEV
Pick-up
command
Video signals (VDO, /VDO)
Primary charging roller
Laser beam
Developing cylinder
Cleaning blade
Cartridge
Blade
Laser/scanner unit
Pressure
roller
Fixing film unit
Fixing unit
Intermediate PCB
Transfer charging
roller
Photo-
sensitive
drum
Engine controller
PCB
Interface controller
PCB