| 摘要 |
PURPOSE:To enhance the control accuracy of a hue by measuring the dot area of the dot image of each color on newly printed matter and the mean density in a dot to compare the same with reference values and controlling the supply amount of ink and that of damping water so as to bring the obtained deviation values to zero. CONSTITUTION:In the hue control apparatus of a planographic printing press, the dot area A of the printed-off printing paper of a final color and the mean density D in a dot 24 are detected by a color television camera 2 equipped with a microscope unit 21. These detection signals are sent to a measuring control apparatus 3 and the obtained control signal is sent to the ink blade moving motors 5 - 8 of an ink supply apparatus and the water fountain roller rotating motors 18 - 21 of a damping water apparatus and the respective motors are controlled to control the supply amount of ink and that of damping water so as to keep a hue constant. At this time, the dot area A and the mean density D are compared with respective reference values to perform control so as to bring the deviation values obtained as the result of comparison to zero. |
