Specifications

10-3. Exposure Lamp LA1 Control
•
The voltage applied to Exposure Lamp LA1 is controlled by changing the
duty ratio of the pulse width of the Exposure Lamp Control signal
(AVRPWM*) output from Master Board PWB-A.
* AVR is an acronym for Auto Voltage Regulator.
PWM is an acronym for Pulse Width Modulation.
•
For possible contamination of the optical system and to incorporate any
correction made in the grid voltage, the copier automatically varies the
optimum intensity of the LA1 light and adjusts AE Sensor gain to ensure
stabilized image quality. (For details, see "IMAGE STABILIZATION
SYSTEM.")
1075T96MCA
<To lower the image density, the Lamp voltage is reduced.>
t
H
L
T
t'
(t > t')
t'
Period T Pulse Width t / Period T
Duty Ratio (%) =
<To raise the image density, the Lamp voltage is increased.>
(t > t')
Duty Ratio (%) =
Period T - Pulse Width t
Period T
(1) LA1 ON/OFF Control
◆
LA1 ON/OFF Timing
•
LA1 turns ON and the Scanner starts a scan motion when PC Drum Drive
Motor M5 is energized following the press of the Start Key and paper
take-up.
•
During a return motion, LA1 turns OFF approx. 50 msec. after the start of
the return motion and remains OFF for approx. 20 msec. before turning ON
again. (It turns OFF 50 msec. after the Scanner has returned to the position
of Scanner Reference Position Sensor PC1.)
OFF
PC Drum Drive
Motor (M5)
1075T97MCA
ON
OFF
ON
L
H
H
L
H
Exposure Lamp (LA1)
SCEND Signal
Scanner Reference
Position Sensor (PC1)
Energized
ON
Scan
Start of Return
Return
Scanner stops
at PC1.
Unblocked
L
Blocked
20 msec
50 msec
50 msec
M-37