Ricoh FT8680 Service Manual page 36

PROCESS CONTROL
1.3.9 V Measuring
01
Drum
Potential
Since the ID sensor pattern on the drum is made by the erase lamp and
charge corona (except for B4/8
movement. See toner density detection and supply section for details), the
sensor pattern density varies with drum potential just after the charge corona
(V ) is applied.
0
To measure the toner density properly, the development bias for the ID
sensor pattern is corrected by measuring the actual drum potential after the
charge corona.
During the process control data initialization, the drum potential after the
charge corona is applied when the drum sensitivity is stabilized (V
measured and used to determine the bias voltage for the ID sensor pattern
development in continuous copy run. The details will be explained in the
toner density detection section.
V
0
Vd
Dark Original Density
" x 14" copy mode due to the lens horizontal
1/2
2-12
31 July 1995
Light
A171D513.wmf
) will be
01