Ricoh FT4227 Manual page 308

12 February 1992
6.5.5 Bias Voltage Selection by SP Mode
SP37: Black Bias
SP79: Color Bias
Data Density
0 Normal
1 Darkest
2 Darker
3 Lighter
4 Lightest
The development bias for original image can be selected from among four
levels by SP mode #37 for black and SP mode #79 for color as shown in the
above table.
The selected development bias voltage does not affect the toner density
control because the development bias for the ID sensor patterns have a
different table.
Since the V pattern and V
R
cycles, the setting of SP37 is applied to the development bias voltage for the
V and V patterns. Therefore, if you change the black development bias
R L
after the initial V detection, the difference will be gradually neutralized by the
L
exposure lamp voltage when the subsequent V
(Ex. If you decrease the negative development bias voltage by +40V to get a
darker image, the V
voltage increases by 1V. After several V
darkened by the development bias voltage will return to the initial image
density as a result of V
adjustment should be done with the exposure lamp voltage adjustment
(SP48) only when the drum initial setting (SP66) is performed.
The color development bias voltage can be adjusted any time.
Develpment Bias
Correction Voltage
±0V
+40V
+20V
–20V
–40V
pattern detections are performed in black copy
L
pattern will also become darker and the exposure lamp
L
pattern detections.) The development bias voltage
L
2-53
detections are performed.
L
pattern detections, the image
L
DEVELOPMENT