Specifications

(2) Auto Exposure Control
<Overview>
•
The copier is provided with the Auto Exposure mode in which the
voltage applied to LA1 is automatically increased or decreased as
necessary so that copies of consistent quality are produced regardless
of whether, for example, the original has a dark background or is a
pencil line drawing.
•
AE Sensor Board PWB-H beside the Lens measures the intensity of the
light reflected off the 3rd Mirror, which results in the black/white ratio of
an area of 210 mm (W) × 8 mm (L) of the original being measured. As
the original is being scanned in the Auto Exposure mode, PWB-H
senses the image density of the original (or the intensity of the light
reflected) on a real-time basis.
•
In this mode, the copier either increases or decreases the LA1 voltage
according to the difference between the AE Sensor output and reference
voltage during the period between when the Image Leading Edge signal
(BASE) is output and when LA1 is turned OFF.
Exploded
View
Original
3rd Mirror
AE Sensor Board
PWB-H
210 mm
Surface of Original
3rd Mirror
Scan
Direction
AE Sensor Board
PWB-H
Slit
This area corresponds
to a 210-mm-wide band
across the original.
210 mm
A Given
Distance
8 mm
M-38