Laserdiode Drive - Epson C11C605001 - DFX 9000 B/W Dot-matrix Printer Service Manual

Operating Pnnciplea
Laser Diode Drive
2.1.3.5
Figure 2-30 is a laser diode drive arcuit. Laser diode emission is amtrolled by four signals (DATA,
DATA
MO 4
Bead (MCU PWB)
The DATA signal is the laser on/off signal. When it is LOW, the laser is allowed to emit and when
it is HIGH, the laser is stopped.
The MO is the laser emission power monitor analog signal. The engine controller board (MC PWB)
adjusts the laser emission power by VL2 and VLl signals. VL2 and VL1 are laser emission power
adjust signals, they are analog signals.
If the ~ signal is not detected, it will be judged that there ia a laser diode
If the SOS signal is not detected, it would be judged as a scanner motor malfunction.
2-18
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Figure 2-30. Laser Diode Drive Circuit
malfunction.
Rev. A