| 摘要 |
<p>PURPOSE:To make it possible to form images with a constantly fixed density, by arranging a multiplicity of minute light-emitting elements in an array, dividing the elements into a plurality of groups along the array direction, providing a temperature- detecting elements for each of the blocks, and controlling the light exposure of the light-emitting elements in the block corresponding to a given one of the temperature- detecting elements according to the value detected by the temperature-detecting element. CONSTITUTION:The temperature of an LED array 101 is higher at a central part than at both end parts, and the pulse with of an enable signal EN2 is set to be larger than those of enable signals EN1, EN3. Therefore, LED elements 106, 106... in a central block B2 having the higher temperature and a smaller light exposure have a longer light emission period per one piece of image data, whereas LED elements 106, 106... in end blocks B1, B3 having a lower temperature and a greater light exposure have a shorter light emission period. Thus, even where the light exposure of the LED elements 106, 106 varies according to the temperature, control of the light emission period per one piece of image data according to the temperatures of the LED elements enables constantly uniform image exposure along the arrangement direction of the LED elements 106, 106..., and high-quality images can be formed.</p> |
