| 摘要 |
<p>PURPOSE:To provide an optical printer which can keep excellent gradation reproducibility without decreasing the gradation reproducibility even by use for a long period by a method wherein decrease of the gradation reproducibility by decrease of light emission efficiency change with time of a light emission element is compensated for. CONSTITUTION:Decrease of a light emission quantity of an EL light emission element array printer head 6 is detected with an optical detector 7. A gradation threshold stored in a gradation threshold value preserving ROM 4 is corrected according to its condition to be mended to downward, and a number of times of light emission and light emission time are increased. Otherwise, the number of times of light emission and light emission time themselves are corrected according to decrease of light emission efficiency to be increased. Decrease of the light emission quantity of the light emission element of the EL array printer head 6 caused by decrease of the light emission quantity of the light emission element is compensated for thus, and excellent gradation reproducibility of the optical printer is maintained during use for a long period.</p> |
