Ricoh FT5540 Service Manual page 80

31 August 1989
The CPU checks the voltage output by the auto ID circuit. This circuit has a peak hold
function. The peak hold voltage corresponds to the maximum reflectivity of the original. Based
on the peak hold voltage, the CPU determines the proper bias base level and sends a 4-bit
control signal to the power pack. The power pack then applies the proper bias to the
development roller.
SP 56
A new function has been added to enable the service engineers to quickly adjust for ADS
sensor discrepancies.
All ADS sensor functions are related to an ADS sensor value of 3.0 volts for white paper.
Previously if this value was incorrect the ADS functions might not have worked properly and
the variable resistor for the ADS sensor would have to be adjusted.
Now, using SP 56, a correction factor can be stored in memory so that if the ADS sensor
voltage is slightly out, the variable resistor does not have to be adjusted. (See ADS Reference
Voltage Setting.)
2-32
Auto ID Peak Hold Input Voltage