Ricoh A085, Руководство пользователя, Страница: 309 / 617

6.5.6 Bias for Sensor Patterns
(1) Development bias voltage for ID sensor pattern
The development bias voltage for the ID sensor patterns (both Vsg and Vsp)
are shown in the above table. They differ depending on color because the
relation between the reflected light intensity and developed sensor pattern
density is different from color to color. The difference of development bias
voltage for each color’s ID sensor pattern compensates them.
The development bias voltage for ID sensor pattern is –20V more for the first
500 copies than that for the rest. This is to compensate a tendency of the
developer to have a slightly higher toner density until it stabilizes.
The toner density can be adjusted by changing the setting of SP33 for black
and that of SP75 for color, as shown in the table.
(2) Development bias voltage for V
R
pattern
The development bias voltage for non-image area is applied to the bare
drum where Vrg output is sampled.
0V is applied for the V
R
pattern which gives Vrp output, as explained in
the process control section.
(3) Development bias voltage for V
L
pattern
The base development bias voltage (VB0–20V) for the V
L
pattern (both
Vlg and Vlp) is decided in the process of the initial V
L
pattern detection.
The actual bias voltage for the V
L
pattern has some corrections.
Data
Black Toner
Density
Development Bias Voltage for
ID sensor Pattern
0~500 501~
0 Normal –220V –200V
1 Lighter –180V –160V
2 Darker –240V –220V
3 Darkest –260V –240V
SP33: Black Pattern Bias
Data
Color Toner
Density
Development Bias Voltage for ID sensor Pattern
0~500 501~
Red/Blue Green Red/Blue Green
0 Normal –200V –240V –180V –220V
1 Lighter –160V –200V –140V –180V
2 Darker –220V –260V –200V –240V
3 Darkest –240V –280V –220V –260V
SP75: Red/Blue/Green Pattern Bias
DEVELOPMENT 12 February 1992
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