Automatic Image Density Control System (Ads) - Ricoh FT6645 Manual

23 April 1993 OPTICS

3.8 AUTOMATIC IMAGE DENSITY CONTROL SYSTEM (ADS)

[B]
[A]
In ADS mode the original background density is sensed by the ADS sensor
[A] and the main CPU determines an appropriate development bias voltage
for the original to prevent dirty backgrounds from appearing on copies.
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 direct the reflected light from the original to the ADS sensor.
The ADS sensor standard voltage is adjusted to 2.7 V when process control
data initial setting is performed. The exposure lamp turns on with ID level 4 at
the home position and the light reflected by the ADS pattern [B] (white
painted) reaches the ADS sensor. The main CPU adjusts the ADS gain data
automatically to make the output 2.7 V. This gain data is stored in the RAM
board.
2-39