| 摘要 |
PROBLEM TO BE SOLVED: To transmit horizontal synchronous signals without influences of noises by making a fall edge of a pulse frequency divided from a detection output pulse the horizontal synchronous signal to a laser of an odd number and transmitting a rise edge of the pulse as the horizontal synchronous signal to a laser of an even number. SOLUTION: Generated horizontal synchronous signals corresponding respectively to first and second lasers are frequency divided by an IC4 and transmitted as BDT signals to an IC3. The IC3 judges a fall edge of the transmitted BDT signal as the horizontal synchronous signal corresponding to the first laser and a rise edge as the horizontal synchronous signal corresponding to the second laser, and controls an image write position or the like. Since a pulse width of the BDT signal can be made twice a pulse width of a normal BD signal, even if countermeasures against extraneous noises are more intensely carried out to a transmission line for the BDT signal thereby making a signal waveform dull, the correct horizontal synchronous signal can be transmitted owing to the large pulse width.
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