Ricoh FT6645 Manual page 79

DEVELOPMENT 23 April 1993
4.5.2 Toner End Detection
[A]
The toner end sensor [A] detects if sufficient toner remains in the toner
hopper or not. The toner end sensor monitors toner end condition once when
the toner supply clutch turns on. When there is little toner inside the toner
hopper and toner pressure on the toner end sensor becomes low, the toner
end sensor outputs a pulse signal for each (one detection per one copy).
The toner near end indication is displayed on the LCD after receiving the
pulse signal 150 times (If no pulse signal is output twice continually, the pulse
count is canceled).
Fifty copies are allowed after entering toner near end condition. After fifty
copies are made in toner near end condition, the machine enters the toner
end condition and copying is prohibited.
When the main switch is turned off and on, or the front door is opened and
closed, the machine drives toner supply mechanism and monitors the toner
end sensor output. If the toner end sensor does not output the pulse signal
twice continually, the toner end condition is canceled.
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