| 摘要 |
PROBLEM TO BE SOLVED: To cause an LED element on an LED head to emit a light with a uniform brightness and thereby form a high-quality image free from a density dispersion. SOLUTION: A light emitted from an LED element 11 is detected by a light- receiving sensor 12, then a voltage from the light-receiving sensor 12 is output to a comparison circuit 13, and is compared to a previously set value by the comparison circuit 13 for determining which is larger. Next, a digital value to be output in accordance with the comparison results is changed by an up/ down counter 14. Thus an electric current value to be output by a D/A converter 15 is changed, so that the electric current which is thus output drives the LED element 11. |
