Ricoh FT 4015 Service Manual page 46

TONER SUPPLY 20 December 1996
6.5.3 Fixed Supply Mode
If 4 is selected with SP30, the TD sensor is not used for toner supply control.
A fixed amount of toner is supplied every copy cycle. The toner supply
amount is determined by the SP32 setting.
6.5.4 Abnormal Condition in Toner Density Detection
If the output of the TD sensor goes below 0.2 volts (indicating far too much
toner), the CPU determines that the toner density supply is abnormal. The
CPU changes from the detect supply mode to the fixed supply mode. At the
same time, either the Auto ID indicator or the selected manual ID level starts
blinking, and the machine can be used. No SC code is generated. Under this
condition, the machine will not perform the toner end detection.
If the value recovers above 0.2 volts, or the main switch is turned off and on,
this condition is canceled and the toner density detection will recover to the
toner supply mode that was in use immediately before the abnormal condition
occurred.
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