Minolta Di620, Manual, Page: 32 / 466

M-13
1155SBM0502A
5-2. Control Methods of the Image Stabilizing System
➀
AIDC Sensor Control
➁
Grid Voltage Control (Vg)
●
Controls are implemented as follows.
➀
-1. Adjustment of AIDC Sensor Disparity (coarse adjustment)
This adjustment is required when normal correction of AIDC contamination and
disparity (installation disparity, circuitry error, drum deterioration, etc.) fails to
bring operation to within the appropriate range. To make the adjustment, the
drum surface is erased and an AIDC pattern is generated on it. A 4-bit analog
switch (charge-resistance switch) is then set so as to bring the voltage deter-
mined by the combination of the switch setting and the AIDC sensor output to
approximately 1 volt.
➀
-2. Adjustment for AIDC Sensor Contamination (fine adjustment)
Contamination of the AIDC sensor by toner or other material will cause a drop in
the sensor output voltage. This must be corrected for if the AIDC sensor is to
continue providing reliable reference values. To make the adjustment, the drum
surface is erased and an AIDC pattern is generated on it. LED current is then
adjusted to bring the AIDC sensor output voltage to 1V.
➀
-3.
∆
V Control
Drum deterioration and environmental factors may lead to a drop in drum sensi-
tivity and drum surface potential, resulting in ID loss. To correct for this, grid volt-
age (Vg) and bias voltage (Vb) are adjusted to bring the AIDC sensor output
voltage into the range between 4.27V (lighter) to 4.29V (darker).
➁
Grid Voltage Control (Vg)
This control corrects for a loss in drum surface potential caused by drum deteriora-
tion (loss of surface material). Correction is made by increasing the Vg by 1 step
after 70 hours of drum rotation.
CONTROLLED
PART
CONTROL SIGNAL WIRING DIAGRAM
AIDC Sensor PJ10A-1B C-4
CONTROL CONTROL VALUE INITIAL VALUE
Grid voltage
−
365V to
−
905V
−
653V