Canon LBP-1260, Руководство по обслуживанию

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CHAPTER 2
control
circuit
outline
DC controller
i
Laser
driver
Laser driver
2-12
This circuit switches the laser diode (LD]
ON and OFF at a constant intensity In
response to the signal from the video
controller. The sent from the
video controller to the DC controller, goes
to the switching circuit in the laser driver
circuit as It Is as the signal
The microprocessor
outputs the INTENSITY CONTROL signals
APCOS) from the DA output ports
to the analog adder circuit according to the
internal data. The APCOR and APCOS
signals are added to this circuit at a ratio
of approximately to 1. and then sent to
the laser current setting circuit located in
the laser driver as the AUTOMATIC
POWER CONTROL OUTPUT signal
The CPU adjusts the value of the
APCOUT signal by changing the APCOR
signal for coarse adjustment, and the
APCOS for fine adjustment.
The output current of the laser current
setting circuit sent to the switching
circuit and the laser diode is switched ON
and OFF in response to the signal
when the VIDEO DATA ENABLE signal
described later) is