Image Stabilization System Control - Minolta Di450 Service Manual

5-2.

Image Stabilization System Control

1. AIDC Sensor Coarse Adjustment
• The following adjustment is made to prevent the AIDC Sensor output voltage from deviat-
ing from the specified range due to part-to-part variations in the AIDC Sensor (installa-
tion, circuit, deterioration, etc.).
• The load resistance value is set with the 4-bit analog switch so that the AIDC Sensor out-
put voltage becomes approximately 1volt in terms of the background level to be erased.
2. AIDC Sensor Fine Adjustment
• The following adjustment is made to prevent the AIDC Sensor output voltage from being
varied by toner or other contamination of the sensor.
• The LED current value of the AIDC Sensor is varied so that the AIDC Sensor output volt-
age becomes 1 volt in terms of the background level to be erased.
CONTROLLED PART
AIDC Sensor
∆V Control
3.
• Drum deterioration and environmental factors may lead to a drop in drum sensitivity and
drum surface potential, resulting in ID loss.
• To correct for this, grid voltage (Vg) and bias voltage (Vb) are adjusted to bring the AIDC
sensor output voltage into the range between 4.40 V (lighter) to 4.45 V (darker).
4. Grid Voltage Control (Vg)
• This control corrects for a loss in drum surface potential caused by drum deterioration
(loss of surface material). Correction is made by increasing the Vg by 1 step after 50
hours of drum rotation.
CONTROL
Grid voltage
CONTROL SIGNAL
PWB-A PJ7A-7B
CONTROL VALUE
−366 V to −924 V
M-8
WIRING DIAGRAM
4-D
INITIAL VALUE
−600 V