| 摘要 |
PURPOSE:To record a high gradation image at a high speed by having a light output stabilizing circuit to feed back a signal corresponding to the strength of an optical beam to a light emitting level command signal and a correcting table to compensate the non-linearity of the output characteristic of a laser by a laser action control circuit, inputting a test signal to the above-mentioned control circuit and preparing the correcting table. CONSTITUTION:A laser action control circuit is equipped with a correcting table 40 to correct a light emitting level command signal S1 so as to compensate the non linearity of the driving current pair light output characteristic of an APC circuit 8 and a laser 1 and to make linear the relation of the laser output after compensation and the signal S1 before correction, and a table preparing means 70 to input a test signal S10, in which a level is changed, to the above-mentioned control circuit and prepare the correcting table 40 based on the relation of the then beam strength and the signal S10 is provided. When the signal S1 is corrected by the correcting table and the gain of the APC circuit 8 is low, the relation of the signal S1 before correction and the laser output can be made linear. Since the correcting table can be updated at all times by providing the means 70, for example, even when a change with the passage of time is executed for the performance of the laser, the correcting table can be always suitably maintained. |
