| 摘要 |
PROBLEM TO BE SOLVED: To stably control the light quantity of a specified semiconductor laser by restraining the light quantities of all the semiconductor lasers to be as small value as possible just before controlling the bias current of the semiconductor laser or making only the specified laser whose light quantity is controlled emit light and restraining the emitted light quantities of other lasers to be as small as possible. SOLUTION: As for a 1st laser diode 10, a bias and write sampling signal is not outputted but a 1st bias off signal becomes low just before a 2nd sampling section and only in the sampling section, so that the laser diode 10 is turned off. At such a time, the data of a 1st minimum light quantity setting circuit 43 and a maximum light quantity setting circuit 44 hold previous sampling data. As for a 2nd laser diode 12, a 2nd bias off signal becomes low only just before the sampling section, so that the laser diode 12 is turned off. Therefore, the light quantities of the laser diodes 10 and 12 are fixed and stable light output is always obtained in a printing section.
|
