To maintain the correct image density, the lamp data is incremented when
the reproduction ratio is changed or drum wear correction or V
L
correction is
done. This increment in the lamp data increases the intensity of light reflected
from the original. Therefore, the auto ID sensor output voltage also changes.
In order to maintain a constant voltage for the same original when the lamp
data is incremented, the threshold levels are shifted with each increment in
the lamp data as shown in the following table.
❋
Increase of lamp data
❋
+0
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+11
+12
TL1
0.80
0.82
0.86
0.89
0.91
0.93
0.95
0.99
1.01
1.04
1.05
1.07
1.10
TL2
0.75
0.77
0.81
0.83
0.86
0.88
0.90
0.92
0.95
0.97
1.00
1.02
1.04
TL3
0.70
0.72
0.75
0.76
0.79
0.81
0.83
0.84
0.88
0.90
0.93
0.95
0.97
TL4
0.60
0.62
0.64
0.66
0.69
0.70
0.72
0.74
0.76
0.77
0.80
0.81
0.83
TL5
0.29
0.29
0.30
0.31
0.33
0.33
0.34
0.35
0.36
0.36
0.37
0.38
0.37
❋
+13
+14
+15
+16
+17
+18
+19
+20
+21
+22
+23
+24
TL1
1.11
1.11
1.11
1.12
1.13
1.13
1.13
1.13
1.13
1.13
1.13
1.13
TL2
1.05
1.06
1.07
1.08
1.10
1.11
1.13
1.13
1.13
1.13
1.13
1.13
TL3
0.98
0.99
1.02
1.05
1.07
1.09
1.12
1.13
1.13
1.13
1.13
1.13
TL4
0.85
0.86
0.86
0.88
0.91
0.93
0.95
0.98
0.99
1.02
1.05
1.08
TL5
0.38
0.39
0.42
0.43
0.44
0.45
0.46
0.47
0.48
0.49
0.51
0.52
5.4.3 Base Bias Voltage Adjustment Factor
Base Bias Adjustment
(Black toner: SP37, Color Toner: SP79)
Image density
SP data (SP37 or 79)
Change of base bias voltage
Normal
0
±
0 volts
Darkest
1
+40 volts
Darker
2
+20 volts
Lighter
3
–20 volts
Lightest
4
–40 volts
The base bias voltage can be changed in SP37 for black toner or SP79 for
color toner to adjust the image density level. The above table gives the base
bias voltage for each SP mode setting. This adjustment should be done only
when the exposure lamp voltage adjustment (SP48) fails to achieve the
desired image density.
FT4220/4222
2-32
STM
Summary of Contents for FT4215
Page 1: ...FT4220 4222 4215 SERVICE TRAINING MANUAL ...
Page 12: ...SECTION 1 OVERALL MACHINE INFORMATION ...
Page 28: ...8 AC POWER AND DC POWER DISTRIBUTION FT4220 4222 1 16 STM ...
Page 31: ...SECTION 2 DETAILED SECTION DESCRIPTIONS ...
Page 114: ...SECTION 3 DOCUMENT FEEDER ...
Page 138: ...SECTION 4 SORTER ...
Page 157: ...SECTION 5 DUPLEX ...