Development Mechanism - Gestetner B070 Service Manual

6.12.2 DEVELOPMENT MECHANISM

[H]
Toner and developer are mixed in the toner agitator by the cross-mixing roller [A].
The paddle roller [B] picks up the developer and sends it to the upper development
roller [C]. Internal permanent magnets in the development rollers attract the
developer to the development roller sleeve. Developer from the upper development
roller sleeve is also attracted to the lower development roller [D].
The upper development roller carries the developer past the doctor blade [E] which
trims the developer to the desired thickness. Backspill (excess toner) spills over the
separator [F] to the toner transport coil [G] which sends the developer from back to
front to the cross-mixing roller.
In this machine, black areas of the latent image are at a low negative charge (about
–150 V) and white areas are at a high negative charge (about –800 V).
The development roller is given a negative bias to attract negatively charged toner
to the black areas of the latent image on the drum.
The development rollers continue to turn, carrying the developer to the drum [H].
When the developer brush contacts the drum surface, the low-negatively charged
areas of the drum surface attract and hold the negatively charged toner. In this
way, the latent image is developed.
SM
CÓPIA NÃO CONTROLADA
[E]
[F]
[C]
[D]
6-71
CÓPIA NÃO CONTROLADA
DEVELOPMENT
[G]
[A]
[B]
B070D303.WMF
B070/B071