Lexmark 500n manual Laser drive control circuit

Models: 500n

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Laser drive control circuit

The laser drive control circuit (LDC) consists of a video signal input circuit, laser drive circuit, laser diode, output sensing circuit, and output control circuit. See the illustration.

1.When the video signal is received, the laser drive control circuit switches the laser diode switch on and radiates according to the video signal.

2.The radiated laser beam senses the photo detector (PD). The detected signal is returned to the output control circuit.

3.The output control circuit controls the radiated output to a constant, by comparing the laser output default with the feedback value transmitted from the output sensing circuit.

4.The laser beam, scanned by the scanner motor, is sensed by the beam detector (PD), and then outputs the beam detecting timing (BDT) signal.

General information 1-37

Page 59
Image 59
Lexmark 500n manual Laser drive control circuit