In actual printing, the phenomenon of unreal printing in the field is often encountered. In the past, printing pressure and paper were first considered. Usually, when the printing pressure cannot be solved, the paper can only be changed, but this not only increases the printing cost, but also delays the production cycle. . In the following two cases we have solved this problem fundamentally by adjusting the printing process.
Example 1: In the actual production often encounter 30% to 50% of the magenta version and 100% cyan overprint blue solid, often due to poor paper red net flower phenomenon, and switch to paper good paper The problem is solved and it is clear that paper is the main cause of this failure. But can we solve this problem by adjusting the process? Through analysis, the conventional color sequence for printing is black, cyan, magenta, and yellow. The magenta nets are overprinted on the freshly printed cyan field. In order to prevent anti-peeling, the viscosity of magenta ink is reduced, and the viscosity of blue ink is increased. The problem has not been solved. Although the effect of using imported ink is better, it is still not ideal. After analysis, because the four-color machine is a wet-and-overprint, when the other ink is overprinted in the wet field, the transfer effect is poor, and the ink transfer rate is low. Try to exchange the magenta and cyan printing color sequence, and print first. Red net, this sample red net can be 100% transfer to the paper, the highest transfer rate, and more than half of the green version of the field can also be directly transferred on the paper, so that the printed print is very flat, the problem is A fundamental solution is that even if the paper is replaced with a slightly inferior one, it can be printed.
Example 2: Once, use 150g/m2 offset paper to print book cover, the layout of which has a large area of ​​green plate. When looking for the rules, it used copperplate paper, which was very flat in the field. However, when it was changed to 150g/m2 offset paper, the phenomenon of serious flowering on the ground was severe, and the increase of printing pressure was also ineffective. It was apparent that the offset paper was rough and poor in ink affinity. Since cyan is in the second group, the paper is poorly ink-receptive, and it is not firmly bonded with the ink. The printed blue ink will peel off part of the back two sets of blankets. So can a single Indian ink be printed? We left the rest of the machine pressure group, only printed cyan, the result was printed on the ground is very flat, so we adjusted the printing color sequence, the cyan version in the final group, print hair flower troubleshooting.
Through the elimination of the above two cases of failure, it was found that the printing color sequence has a great influence on the ink transfer, especially for multi-color printing wet and dry overprinting, and it is necessary to flexibly adjust the printing color sequence according to different jobs.
