| 摘要 |
PROBLEM TO BE SOLVED: To provide a double-detecting method and a double-measuring method to measure a double precisely and rapidly by solving the problem that a phenomenon called a double occurs, wherein when a multicolor printing is carried out using a plurality of units each having a plate cylinder, colors transferred to a second plate cylinder and following plate cylinder are displaced and transferred again, whereby the density of ink varies on every sheet or on the right and left sides thereof and the density at a half tone is very high for a proof sheet. SOLUTION: A double detecting mark is formed from a small circular center mark and an annular mark concentrically encircling the center mark. The long diameter and the short diameter of the printed double detecting mark are measured, and if there is a difference between both the diameters, the difference is made a double amount, while a long diameter direction passing through the center mark is detected to detect a double. |
