4.8 AUTOMATIC IMAGE DENSITY CONTROL SYSTEM (ADS)
Just before taking a copy in ADS (Auto Image Density Select) mode, the
ADS sensor [A] measures the original background density and the main
CPU changes the development bias for the original to prevent dirty
background from appearing on the copy. The exposure lamp voltage is fixed
at the manual ID level 4 value (set by SP4-001) regardless of the input from
the ADS sensor.
The ADS sensor board is mounted on the rear side of the optics side plate.
The sensor board is covered by the sensor housing cover which has a small
hole to allow light reflected from the original to reach the ADS sensor.
ADS Sensor Gain Adjustment (Every 1,000 Copies)
To maintain consistent image quality regardless of changes in the
components of the optic path with time, the ADS sensor reference voltage is
adjusted to 2.7
±
0.1 V every 1K copies. The exposure lamp turns on at ID
level 4, and the light reflected by the white ADS pattern [B] reaches the ADS
sensor. The CPU adjusts the ADS gain value to make the output (V
ADS
pattern) equal to 2.7
±
0.1 V. The gain value is stored in the RAM board.
If the output cannot be made to equal 2.7
±
0.1 Volts even if the gain is
adjusted as far as it will go, the machine generates a Service Call code.
[B]
[A]
Detailed
Descriptions
STM 2-49 A156/A160/A162
To Next Page
Loading...
Need help?
General
