| 摘要 |
PURPOSE:To check the abnormality occurring in a printed matter to enhance a checking speed by comparing a detection signal obtained by optically scanning the printed matter running with a detection signal of a normally printed matter as a reference signal which has been previously detected by the same method and stored. CONSTITUTION:Image information of a printed matter which is running is accumulated in a processing circuit 6. The processing circuit 6 has both reference information storing the image pattern of a normally printed matter and check information storing the image pattern of a printed matter successively fed. An ink density fluctuation is caused by the excess or shortage of an ink amount supplied to a plate cylinder 8 from an ink key mounted on a printing part 1. Therefore, the density fluctuation may be detected by every width of the ink key controlling the ink amount. Then, the reference information is divided correspondingly to the respective ink keys, the representative reference information in the respective blocks are extracted, and reference data is formed. Additionally, the check information is extracted correspondingly to the reference data, and check data is formed. Then, the reference data and the check data are compared with each other. If the difference is more than a predetermined value, the printed matter is judged to be of unsatisfactory density. |
