Ricoh FT8680 Service Manual page 76

TONER DENSITY DETECTION AND SUPPLY
7.5.2 Toner End Detection
When little toner remains in the toner tank, the amount of toner supplied to
the development unit decreases, and the image of the ID sensor pattern gets
lighter.
When the Main PCB detects the low ID sensor pattern density condition
(Vsp/Vsg ≥ 1/9) more than three times in a row during the toner near end
condition (physical check), or when main PCB counts 2000 or more copies
made since the toner near end condition, the toner end condition is displayed
on the CRT screen and copying is inhibited until the toner cartridge is
replaced.
Near End
Yes
Copy from
Near End condition < 2
(N.E~)
No
Toner End
Copy
No
Yes
K
Vsp / Vsg ≥ 1/9 3 times
Yes
2-52
31 July 1995
No
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