| 摘要 |
PURPOSE:To prevent excessive current to a laser, in a semiconductor laser output control device using a counter, by resetting the counter by turning ON the power source of a laser driving circuit, and cutting OFF the driving current immediately after the turning ON. CONSTITUTION:When a DC power source of +12 V is applied to a laser printer, a reset signal is generated by a reset circuit 19 and applied to an up and down counter 13 and a laser driving circuit 8 through an inverter 20. The counter 13 is reset, and the driving current for a laser 1 is cut OFF. Therefore, even if the logarithmic value of the counter 13 is increased by the cut OFF of + or -12V, the counter 13 is reset when the power is applied again. A large current does not flow to the semiconductor laser 1, and breakdown can be prevented. |
