Ricoh FT6645 Manual page 34

23 April 1993
1.3.7 V Correction
R
[-V]
Drum
Potential
Dark
Potentials (V , V
R D
only when the fusing temperature is less than 100°C after the machine is
turned on.)
During the check cycle, the V
potential on the area where exposed by each pattern is checked by the
potential sensor.
Compare the curve of the V
curve of the new drum, they are parallel but the compensated potential is still
higher (V ) than the new drum potential. To prevent dirty backgrounds due to
R
increased residual potential, development bias (V
V = V + (–220)
BB R
V
D
V
R
–770
–140
Original Density
, V ) are monitored by the potential sensor. (This is done
L
and V
D
and V
D
V
V
R
V
L
patterns are exposed and the drum
L
compensated drum potential with the
L
) is applied as follows:
BB
2-9
PROCESS CONTROL
and V Compensated
D L
Development Bias (V
New Drum
V
R
Light
)
BB