2. Control Method
Table 3-301 shows the number of measure-
ments and corrections the NP6085 makes.
Table 3-301
a. Primary Current Control
To measure the dark area potential (V
D
), the
NP6085 sends a reference current to the primary
charging assembly and uses the potential sensor
to measure the drum surface potential. The DC
controller PCB compares the measured drum sur-
face potential against the target value and, if the
measurement deviates from the target, the DC
controller PCB corrects the primary charging level
control signal (HVTPC) it generates.
The above mechanism causes the high-volt-
age transformer (HVT1) to send corrected current
to the primary charging assembly.
The NP6085 repeats this sequence of mea-
surement and correction eight times (max), there-
by bringing the dark area potential (V
D
) closer to
the target value.
The target value may be varied using
‘VDT_SW’ in service mode (
)
b. Controlling the Scanning Lamp Intensity
To measure the light area potential (V
L1
), a ref-
erence ON voltage is applied to the scanning
lamp.
The scanning lamp exposes the standard
white plate, and the reflected light is projected to
the drum.
The drum surface potential of the area
exposed to light is measured by the potential sen-
sor, and the result is sent to the DC controller
PCB.
In turn, the DC controller compares the mea-
surement and the target and corrects the intensi-
ty adjustment signal (LINT) it generates if the
measurement deviates from the target.
This way, the lamp regulator applies corrected
voltage to the scanning lamp.
This sequence of measurement and correction
is repeated eight times (max), thereby bringing
the light area potential (V
L1
) closer to the target.
✽
5
✽
3. OPERATIONS AND TIMING
COPYRIGHT © 1996 CANON INC.
CANON NP6085 REV.0 JULY 1996 PRINTED IN JAPAN (IMPRIME AU JAPON)
3-51
Corrections
8 (max.)
8 (max.)
0
V
D
V
L1
V
L2
Measurements
8 (max.)
8 (max.)
1
Copy Start key ON
Scanning lamp
Measurement by potential
sensor
Primary charging
INTR
CNTR1
V
D
V
D
V
D
V
D
V
D
V
D
V
D
V
D
V
L1
V
L1
V
L1
V
L1
V
L1
V
L1
V
L1
V
L1
V
L2
Reference
voltage
Correction
voltage
Final voltage
Reference current
Correction current
Final current
CNTR2
To SCFW or AER
Figure 3-301
Содержание NP6085
Страница 8: ......
Страница 44: ......
Страница 46: ......
Страница 58: ......
Страница 100: ......
Страница 102: ......
Страница 425: ......
Страница 481: ......
Страница 483: ......
Страница 493: ......
Страница 498: ...COPYRIGHT 1996 CANON INC CANON NP6085 REV 0 JULY 1996 PRINTED IN JAPAN IMPRIME AU JAPON A 5 ...
Страница 502: ...PRINTED IN JAPAN IMPRIME AU JAPON 0697AB0 6 3 This publication is printed on 70 reprocessed paper ...