| 摘要 |
<p>PURPOSE:To obtain a stable light source with high energy and longer life by a printer wherein a plurality of light emitting diodes are used as the light source for a light signal irradiating system employing a liquid crystal light valve thereby to illuminate the light source with high frequency in reduced duty ratio. CONSTITUTION:A light irradiating system in a printer wherein a light signal is irradiated on a light conductor 15 and this is developped with tonors so as to obtain picture informations, comprises a light source 11, a liquid crystal light valve (liquid crystal shutter cell) 13, lens systems 12, 14 and a liquid crystal driving circuit 16. The light source 11 consists of a number of light emitting diodes 53 (e.g., GaP) arrayed side by side, which are lit up with high frequency not less than 500Hz in duty ratio less than 1. Those light emitting diodes are preferably illuminated using an output signal which is synchronous with optical response of the liquid crystal light valve 13 and slightly delayed from rising of such response.</p> |
