What should I do if the film is printed off?
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The phenomenon of ink drop phenomenon is relatively low in the printing of paper self-adhesive materials, which is more common in film materials, mainly due to the unstable surface tension of film materials. Under normal circumstances, the reason why the film material is printed off ink is low surface tension of the film material, poor UV curing, and excessive use of the ink additive.
Low surface tension of film material leads to ink loss
In general, the surface tension of the film-like material needs to be more than 38 dynes to ensure normal printing, and to make the ink firmly adhered, it is required to reach 42 dynes or more. If the ink is lost during the printing process, the Dyne pen can be used to test the surface tension value of the material. If it is lower than the above standard, it is recommended to use the online corona or the primer to increase the surface tension of the film material. In order to achieve better ink adhesion.
If there are no conditions to solve the problem by the above two methods, you can also use low surface energy ink to try to solve. Many ink manufacturers currently offer inks specifically for low-surface energy materials, and printing companies can test to find an ink that matches the label material used to solve this problem.
Poor UV curing leads to ink loss
The ink drop also has a lot to do with the curing effect of the UV ink. If the power of the UV lamp is insufficient, or if the printing speed is too fast, a "fake dry" phenomenon will occur, which can easily lead to ink loss. The so-called "fake dry" means that the surface layer of the ink has been dried/cured, and the inside is not completely dried/cured.
It should be particularly noted here that the ink drop caused by this phenomenon occurs mostly in the printing of large-area solid patterns. This is because the amount of ink used in the solid pattern is large, and the inside of the ink layer is not easily cured completely. In addition, sometimes the ink printed at the same time is only a certain color drop ink is more obvious, the most common is the black ink off the ink is serious. This is because UV light is more difficult to penetrate the black ink layer, and in most cases the black ink is arranged to be printed in the last color group, the total curing time is the shortest, and it is not easy to cure completely.
In case of such problems, you can first check if the UV lamp has exceeded the rated service life. If it is exceeded, you need to replace the lamp. If the UV lamp is in the normal service period, then the power of the UV lamp should be insufficient, and the power of the UV lamp can be appropriately increased, or the printing speed can be lowered.
However, for film-type self-adhesive materials, such treatment may cause new problems - when the printing speed is too low or the UV lamp power is too high, it is likely to cause the film-type self-adhesive material to be subjected to heat per unit time. Larger and deformed.
In case of such problems, the amount of ink supply can be appropriately reduced, and the printing speed or the power of the UV lamp can be appropriately increased to ensure the ink is completely cured. If the amount of ink supply is reduced and the printing in the field is falsified, it can be solved by two printing methods if necessary.
Excessive use of ink additives leads to ink loss
The winter weather in the north is relatively cold. Some printing companies will encounter problems of thickening, viscous, and poor ink in the production process. Many operators will use the method of adding ink to increase the fluidity of the ink. However, once the varnish is added too much, it is easy to cause ink loss.
In general, the addition ratio of varnish is 3% to 5%, and if it exceeds this range, it needs to be carefully added.