| 摘要 |
PURPOSE:To reduce a light-emitting quantity fluctuation by keeping permitting a bias current corresponding to exposure quantity which is equal to below the half of exposure quantity corresponding to the least coloring density of photosensitive material to flow to a light source. CONSTITUTION:A three LD beam different angle incident optical system is provided with three semi-conductor laser(LD) 12C, 12Y and 12M which permit light to be made incident to the reflection faces 22a of a polygon mirror 22 by angles which are different little by little as the light sources which emits the light of a prescribed narrow band wave length. In an image exposure device 10, the bias current which emits light by the exposure quantity which is equal to below the half of least exposure quantity for exposing photosensitive material A is permitted to flow in respective LDs 12 so as to be pre-heated and the reflection faces whose reflection coefft. is more than 45% are used as the reflection faces to a light-emitting side for the photosensitive material A of an optical resonator, which constitute respective LDs, in LDs 12. The bias current is not confined to be permitted to flow in all LDs 12 and it is enough to flow in one of LDs, at least. But, it is preferable that the bias current is permitted to flow in all LDs 12 for executing image exposure with high image quality. |
