Ricoh FW870, User Manual, Page: 29 / 206

3.4 FL REGULATOR CONTROL
The FL regulator [A] receives 24 volts dc at CN401-1 from the main board
[B]. The control signal, which is a pulse width modulated (PWM) signal, is
received at CN401-3. The PWM signal has a period (T) of 1 millisecond and
a duty ratio of 15% to 100%.
The basic light intensity level is determined either by the image density
selected at the operation panel (manual ID control) or by the original’s
background level as sensed by the ADS. The CPU uses the light sensor to
monitor the actual light intensity. The light sensor [C] directly detects the
lamp’s light output and feeds a light intensity signal back to CN105-B28 of the
main board [D]. This feedback allows the CPU to compensate for variations
in light intensity due to the lamp’s age or temperature.
[D]
[C]
[A]
A174D511.wmf
EXPOSURE 25 July 1996
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