Cleaning Bias Power Pack - Ricoh FT7770 Service Manual

Cleaning Bias Power Pack

7.
The cleaning bias (+300 volts) is applied to the bias roller. The bias roller
helps keep the cleaning brush clean by attracting negatively charged toner
from the cleaning brush.
Circuit operation begins with the application of +24 volts (VP) to CN240-1.
This is the power source for the high voltage cleaning bias. Additionally,
+24 volts (VA) for the
When the Start key is pressed, the CPU energizes the cleaning bias power
pack by supplying a LOW output at CN206-B3. This action turns on the
LED, and the phototransistor energizes the cleaning bias.
The cleaning bias stops at the same time as the main motor.
photocoupler is applied at CN240-4.
trigger
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April, '89