Canon LBP1760P, Service Manual

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IV. IMAGE FORMATION SYSTEM
A. Outline
The image formation system is the central hub of the printer, and consists of the photosensitive
drum, developing unit, charging rollers, etc.
When the PRINT signal (/PRNT) is sent from the video controller to the engine controller, the
engine controller drives the main motor to rotate the photosensitive drum, developing cylinder,
primary charging roller, and transfer charging roller.
The primary charging roller uniformly applies negative charges on the surface of the photo-
sensitive drum. To form a latent image on the photosensitive drum, the laser beam modulated
by the /VDO signal is exposed onto the photosensitive drum surface.
The latent image formed on the photosensitive drum is changed to a visible image by the toner
on the developing cylinder, then transferred onto paper by the transfer charging roller. Residual
toner on the photosensitive drum surface is scraped off by the cleaning blade. The potential on
the drum is made uniform by the primary charging roller in preparation for the next latent
image.
The cartridge has a toner sensor that detects the toner level and no cartridge.
If the toner in the cartridge becomes lower than the prescribed level or there is no cartridge
installed in the printer, the CPU notifies such information to the video controller.
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CHAPTER 2