Label UV inkjet and ink related printing problems

UV inkjet ink caters to the development trend of high-efficiency production, energy saving and environmental protection in the field of digital label. At present, many foreign research institutions and enterprises are actively developing the UV ink jet ink, and its products have occupied most of the market share of high grade UV ink jet ink. At the same time, some research institutes and ink suppliers in our country have also begun to devote themselves to the development of UV ink jet ink, but unfortunately, the more mature products have not yet been introduced. It also reflects that China needs to be promoted in this field. With the increasing call for environmental protection and the vigorous promotion of relevant environmental policies, UV inkjet inks will surely gain a larger market in the near future.

First, the curing is not thorough

In actual production, many label printing enterprises will encounter the phenomenon that the UV inkjet ink is irradiated by the UV lamp, the surface ink is solidified but the internal ink is not completely cured. The cause of this problem may be due to the fact that the absorption spectrum of the UV ink-jet ink is not matched with the radiation peak of the UV lamp. At this time, the curing match between the UV lamp and the UV ink jet ink should be considered, and the UV ink jet ink is replaced in time; on the other hand, it may be the aging of the UV lamp. The service life of the UV lamp is generally about 1000 hours. If the service life is exceeded, the spectral characteristic curve of the UV lamp will change, and the transmittance of the UV lamp will also change, resulting in the inthorough curing of the UV ink jet ink. Therefore, in the daily production, the relevant personnel of the label printing enterprise should correctly record the use time of the UV lamp, and replace the lamp tube in time to avoid failure. In addition to the above two main factors, the ink thickness of UV inkjet ink should also be fully considered. 

Two. Poor adhesion on thin film materials

UV ink jet ink has a wide range of printing materials, but the problem of poor adhesion is often encountered in the printed film materials. This problem is mainly caused by the difference between the surface tension of the film material and the UV ink jet ink. In order to ensure that UV ink jet ink has better adhesion on the surface of film material, the surface tension of film material should reach 38mN/m or more. For label printing enterprises, suitable film materials can be selected according to the specific type of UV inkjet ink and its performance parameters. In order to make the UV ink jet ink with good adhesion on the film bearing material, it is possible to choose a film material with a surface that can be coated directly (at this time, the matching of the surface coating and the ink jet ink used by the UV) can be considered.

In addition, corona can also be used to improve the surface tension of film materials and improve the adhesion of UV inkjet ink on its surface.

Three. The flexibility of the ink layer after curing is not good

UV inkjet printing labels also need to be processed after die cutting, cutting and so on. Therefore, the flexibility of UV inkjet ink layer is required. If the ink layer is crisp and the flexibility is not good, then the digital label will appear ink cutting and die cutting edge uneven when cutting and cutting. The main reasons are the following two points:

First, overcure.

Due to the solidification of UV ink jet ink, the ink flows through a liquid liquid into a solid state immediately after being irradiated by UV light. In this process, if the power of the UV lamp is too large and the transmission speed of the bearing material is slow, the long time of the UV light irradiation will cause the ink layer to increase brittleness because of the oversolidification, resulting in the yellowing of the print surface, which directly affects the flexibility and appearance characteristics of the digital label, and has an adverse effect on the subsequent processing.

Second, UV ink jet ink composition problem.

The higher the functionality of the monomer in UV inkjet ink, the more complex the three-dimensional net structure formed after the solidification of the ink, the greater the brittleness of the ink layer. Therefore, in the actual production, we must correctly select the UV inkjet ink according to the conditions, and strictly control the curing conditions to avoid over curing.

UV inkjet ink caters to the development trend of high-efficiency production, energy saving and environmental protection in the field of digital label. Some research institutes and ink suppliers in our country have also begun to devote themselves to the development of UV ink jet ink, but unfortunately, the more mature products have not yet been introduced. It also reflects that China needs to be promoted in this field.