Ricoh FT6645 Manual page 33

PROCESS CONTROL
1.3.6 V Correction
L
Exposure
Glass
V Pattern
L
Dirty optics and/or exposure lamp deterioration decreases the intensity of the
light that reaches the drum. In addition to this, the drum sensitivity also
changes during the drum's life. These factors change the drum potential just
after white pattern exposure (V
To check the actual V
stuck underneath the original scale. The pattern is exposed on the drum.
The main control board measures V
adjusts it to a target value by adjusting the exposure lamp voltage (V
The residual voltage (V
is compensated as follows:
Target V Value: V
L
The adjusted exposure lamp voltage (V
next process control data initial setting.
[-V]
Drum
Potential
–770
Dark
: Light Potential).
L
, the first scanner moves under the V
L
) change also affects V
R
= V + (–140)
L R
V
D
V
R
V
R
–140
Original Density
through the drum potential sensor and
L
, so that V
L
) is stored in memory until the
LAMP
2-8
23 April 1993
Only V
D
Compensated
V and V
D L
Compensated
V
L
New Drum
V
pattern (White)
L
LAMP
's target voltage
L
R
Light
).