Fit the adhesion
The adhesion of the aqueous ink to the film-like material and the adhesion with the UV ink when overprinting with each other are formulated. First of all, it is necessary to select a suitable water-based ink so that it can adhere well to the surface of the film-like material. Secondly, it is necessary to pay attention to whether the water-based ink material or the varnish can be overprinted with the UV ink, if it cannot be overprinted or overprinted, UV If the adhesion of the ink is not good, it is necessary to consider printing a special coating between the two to ensure the quality of the overprint. Otherwise, the ink of the UV ink printed on the surface of the aqueous ink will not pass the 3M tape test.
Control the relationship between ink pressure and printing pressure
If UV ink is used for printing, the printing pressure is slightly larger, which has little effect on the quality of the label. However, if water-based ink is used for printing, the printing pressure is too large, and the edge of the image is likely to produce "wild ink", which causes problems such as dirt and burrs. If it leads to unnecessary waste, it will not be worth the loss.
Note the difference between two-layer ink printing and one layer ink printing
Usually, in large-area field printing, most label printing companies use two layers of ink to avoid the occurrence of dirty spots. In fact, there is another reason for doing this: in the case of the same color density, the two layers of thin ink are used less than a layer of thick ink.
It should be noted that when printing a thicker layer of ink, the flatness of the ink is usually not so good, it is easy to bloom, not real, and the color looks slightly lighter. If printing on coated paper, the penetration of the ink will aggravate this phenomenon; however, when printing two layers of ink, the situation is different. The first layer of ink is usually printed thinner, except that it can be carried away on the substrate. In addition to the dirty spots, it can also fill the gaps or unevenness on the surface of the printing material. After printing the second layer of ink, the printing effect in the field will be more flat, and the density value measured by the instrument will be higher.
Determine if you need to glaze
Glazing has two purposes: one is to increase the gloss of the label, and the other is to protect the label from wear. If it is just to increase the gloss, the flexo ink itself has a certain brightness, so there is no need to polish it. If it is to protect the label, some labels have no possibility of wear and tear during transportation and use, and do not need to be glazed. If you do not consider the actual situation, you will choose the glazing process blindly, which will lead to unnecessary varnish loss. Although the price of varnish is cheaper than that of ordinary inks, varnish is often full-coated, and the coating is thick, so the amount of use is large, resulting in waste.
Therefore, in the previous process design, we need to consider all aspects, such as whether it is necessary to glaze, or whether it needs a full version of glazing. If the position where the label is attached does not rub at all during labeling, transportation, and use, then the ultra-transparent label may not be glazed. If it is a special-shaped label, because it needs a large area of die-cutting, then there is no need to full-plate glazing, only partial glazing is required. For the part that needs to be glazed, the thickness of the varnish layer should also be considered to meet the customer's requirements. For labels with wear resistance requirements, it is necessary to ensure sufficient varnish thickness, and sometimes even some anti-wear additives need to be added to the varnish. In short, to meet the needs of customers, no need for super quality, super cost, increase unnecessary processes will result in waste of resources.