| 摘要 |
PURPOSE:To heat-sensitively print the character with a constant color depth at all times by detecting the brightness of light image obtained from the photoelectric elements and by keeping the brightness of light source. CONSTITUTION:The light from the light source 9 is made a paralles rays and is thrown on the selected letters and symbols on the letter board 5. The light penetrating through the board shines the charge coupled device (CCD) 14 in which the photoelectric elements are arranged in the form of a matrix. The CCD 14 consists of the image analizing unit 15a, which provides the light images of selected letters and symbols as a matrix data, and the brightness detecting unit 15b which detects the brightness of light. The brightness detecting unit 15b receives a momentary radiation from the light source 9 and emits a detection signal corresponding to the brightness. By this, the output voltage of power supply 10 is controlled and the brightness of light source 9 is also adjusted. |
