Brother MFC 4550, Руководство по обслуживанию

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(3) Developing process
The developing process develops an electrostatic latent image formed on the drum in the
exposing process, into a toner image.
The developer roller attracts the toner particles fed from the toner cartridge by the toner sup-
ply roller, and then conveys them to the contact section with the laser-sensitive drum.
On the contact section between the developer roller and drum, the positive toner particles
stick to the neutralized spots on the drum according to the principles of attraction and repul-
sion, transforming a latent image into a toner image.
The toner augers (which agitate toner particles in the chamber) and the blade allow toner
particles to be fed onto the developer roller at an even thickness.
Laser-sensitive
drum
DC bias
Toner supply roller
Eraser lamp
Transfer roller
Switch “a” (ON for the
transfer process)
Switch “b” (ON for repulsing
toner from the transfer roller)
(4) Transferring process
When a paper passes between the drum and the transfer roller, the switch “a” (see the
above illustration) is turned on to negatively charge the transfer roller. The toner is positive,
so the toner image formed on the drum will be transferred onto the paper according to the
same principle as for the developing process.
If the toner image fails to stick to the paper due to paper jam or other errors, it will stick to the
transfer roller. To repulse this toner, the switch “b” (see the above illustration) is turned on to
positively charge the transfer roller. The toner returns from the transfer roller to the drum.
Cleaning the drum
In the transferring process, not all the toner particles on the drum are transferred onto the
paper but some toner particles remain on the drum. The cleaner roller cleans the drum sur-
face and collects the residual toner. When printing starts or during non-printing, the toner
collected on the cleaner roller will be discharged onto the drum and returned to the chamber
through the developer roller for recycling in the subsequent developing process.
(5) Erasing process
The eraser lamp emits light to expose the drum surface, which erases the residual electrical
charge.
Toner augers
Blade
Developer
roller
Cleaner roller
Chamber
Toner