1.4 COMPENSATIONS DURING COPY CYCLE
During continuous copying, the drum sensitivity changes due to the electrical
fatigue. The drum sensitivity also changes during rest time.
The following compensations are used for the drum sensitivity changes in the
copy cycle:
1.4.1 VL Compensation
The drum light potential (V
L
) is changed during the copy cycle.
To get constant image quality in continuous copy runs, the development base
bias is compensated during the copy cycle.
At the beginning of each original scanning, the V
L
sensor pattern is
developed on the drum. The main PCB monitors the drum potential (V
L2
) of
the latent image of the V
L
sensor pattern through the drum potential sensor,
and adjusts the development base bias.
See development bias section for details.
Development Base Bias:
V
BB
= V
L2
+ 280 –
∆
V + 10 N – 15 M
∆
V = V
L2
– Vr (Maximum
∆
V = 210, Minimum
∆
V = 110)
NOTE: N is the setting for the exposure lamp adjustment in the SP mode.
M is the setting for the Latent Image Adj. in SP mode.
V
L
Pattern
A171D508.wmf
Drum
Potential
Original Density
Dark
Light
V
BB
V
0
Vd
V
L
Vr
A171D510.wmf
PROCESS CONTROL
31 July 1995
2-14
Содержание FT8680
Страница 3: ...SECTION 1 OVERALL MACHINE INFORMATION ...
Страница 8: ...MEMO 31 July 1995 SPECIFICATIONS 1 5 ...
Страница 23: ...6 5 IMAGE OVERLAY MODE 2ND SIDE A171V505 wmf PAPER PATH 31 July 1995 1 20 ...
Страница 24: ...SECTION 2 DETAILED SECTION DESCRIPTIONS ...
Страница 133: ...Timing Chart 1 Stack 2 Paper Feed A171D551 wmf A171D552 wmf 31 July 1995 DUPLEX 2 109 ...
Страница 159: ...SECTION 3 INSTALLATION ...
Страница 177: ...SECTION 4 SERVICE TABLES ...
Страница 229: ...SECTION 5 REPLACEMENT AND ADJUSTMENT ...
Страница 362: ...SECTION 6 TROUBLESHOOTING ...