| 摘要 |
PURPOSE: To realize the execution of the correction of light quantity even to the printing paper surface having no blank paper part thereon, the stabilization of the light quantity at a detecting section after correction and the reduction of the cost of printing paper, the unit price of which is high. CONSTITUTION: Printing paper surface is illuminated with illuminating light source bodies so as to bring the image data of the printing paper surface with the camera in a detecting section 1. At the judgement of the good or bad of printing quality from the image data, a plurality of maximum light quantity picture elements are selected among the brought image data at a maximum light quantity picture element detecting circuit 2 so as to decide and hold the positions of the picture elements in order to calculate the average value of the respective maximum light quantity picture elements. At a difference circuit 4, the average value and the pre-set reference value of light quantity are compared with each other so as to obtain its difference in order to calculate the amount of change of voltage value by using the difference as parameter. By correcting the light quantity of the illuminating light source body by means of the calculated amount of change of voltage value, the illuminating conditions optimum at the detecting section are obtained. |
