Drum Temperature Compensation (V3); Total Bias (Vt) - Ricoh FT4430 Service Manual

16 April '88

5. Drum Temperature Compensation (V3)

monitors drum temperature through a thermistor (TH-2), and it
The CPU
increases or decreases the bias voltage to compensate for variations in drum
sensitivity that are induced by temperature changes in the drum cavity. The
temperature compensation is effective from 5 degrees to 50 degrees
(Celsius).
As shown by the "knee" in the above chart, the temperature compensation
factor depends on the temperature range. Between 5°C and 15°C, the change
V3 is -14 V/"C; between 15°C and 50"C, the change in V3 is -5 to -6V/"C.
in

6. Total Bias (VT)

The total bias applied to the development roller sleeve is the sum of the base
bias and the two compensating factors.
.
(v) ,
22 18 15
TH Resistance
2-30
Temp