Ricoh FT8680, Service Manual

Page: 70 / 389

7. TONER DENSITY DETECTION AND SUPPLY
7.1 TONER SUPPLY MECHANISM
The main PCB monitors the ID sensor pattern density on the drum through
the ID sensor once every ten copies and turns on the toner supply motor
when the pattern density is low (if Vsp/Vsg
≥
1/13).
The toner supply motor [A] turns the toner supply roller [B] for a certain period
based on the paper size and the supply amount set by SP mode.
A brush roller with low rotation torque and that can supply large amounts of
toner even with low operation speed, is used for the toner supply roller.
Toner mixing vanes [C] turn slowly while contacting the inner wall surface of
the toner tank whenever the development motor is turning. This prevents
toner blockages, and supplies toner to the toner agitator [D].
[A]
[B]
[B]
[D]
[C]
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TONER DENSITY DETECTION AND SUPPLY 31 July 1995
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