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3. OPERATIONS AND TIMING m
,---
F. document
Density
Measurement
System
3.
Reading the Output of the AE
Sensor
The
AE
sensor
consists
of
a
1.
Outline
There
is
an
automatic
density
adjustment
(AE) system
which adjusts the
DC component
of the developing
bias to suit
the density of the original.
If the density of
the original is more or less uniform, the AE
function
varies
the DC component
of the
developirig
bias to suit the density
of the
original, so that copies of the correct density
will be made.
photodiode
(Q702)
and
an operational
amplifier
(Q701).
If the strength
of light
striking
the photodiode
is high, the output
voltage (AE) of the amplifier will be small. If
the amount
of light
is small,
the output
voltage will be large.
The DC controller reads the output at a
certain
time after
the zero-cross
signal
(ZXDP) is received from the lamp regulator.
The data representing
the adjusted AE
2.
Operation
The scanner
moves
forward
approxi-
mately 70 mm past the leading edge of the
original
and
stops
momentarily.
The
scanning 'lamp goes ON for approximately
one second,
the image density
is read by
the AE sensor,
and the sensor
output
is
interpreted
by the DC controller.
The DC
controller then adjusts the DC component
of
the developing
bias accordingly.
reference/slope
values
are
Written
to
EEPROM when 'CD3 or 'CD :' is used in the
service mode.
[Approx. 65mm
n
1
(I35
IA4
Approx.
I
30mm
I
Approx.
;
For
reference: I36 size
-
Approx.
ApProx. 36mm
A is the position of the AE sensc~r
25mm
--
Figure 3-27
r
I
i
LrrE
__--_-
__-_____---
i_-__--
AE
sensor PCB
DC controller PCB
Figure
3-28
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