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 labels, and has received widespread attention since its inception. At present, many foreign scientific research institutions and enterprises are actively developing UV inkjet inks, and their products have occupied most of the market share of high-end UV inkjet inks. At the same time, some scientific research institutes and ink suppliers in China have also begun to devote themselves to the development of UV inkjet inks, but unfortunately, relatively mature products have not yet been introduced, which also reflects that China still needs to improve in these 1 areas. With the increasing voice of environmental protection and the vigorous promotion of relevant environmental protection policies, UV inkjet inks will surely gain a larger market in the near future.

1. curing is not complete
In actual production, many label printing companies will encounter UV inkjet ink by UV lamp irradiation, surface ink curing but internal ink is not completely cured phenomenon. The reason for this 1 problem, on the one hand may be due to the UV inkjet ink absorption spectrum and UV lamp irradiation peak does not match, at this time should consider the UV lamp and the UV inkjet ink curing matching, timely replacement of UV inkjet ink; on the other hand may be UV lamp aging. 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 incomplete curing of the UV inkjet ink. Therefore, in daily production, the relevant personnel of the label printing company should correctly record the use time of the UV lamp, replace the lamp in time, and avoid failures. In addition to the above two main factors, but also fully consider the thickness of the ink layer of UV inkjet ink, because the ink layer is too thick also easily lead to ink curing is not complete.  

poor adhesion of 2. on film materials
UV inkjet ink is suitable for a wide range of printing materials, but poor adhesion is often encountered in printing film materials, which 1 mainly caused by the large difference in surface tension between film materials and UV inkjet ink. In order to ensure good adhesion of UV inkjet ink on the surface of the film material, the surface tension of the film material should reach more than 38mN/m. For label printing companies, the appropriate film material can be selected according to the specific type of UV inkjet ink and its performance parameters. In order to make the UV inkjet ink has good adhesion on the film substrate, the film material with a directly printable coating on the surface can be selected (at this time, the matching of the surface coating with the UV inkjet ink used should also be considered)
. In addition, corona method can be used to improve the surface tension of the film material and improve the adhesion of UV inkjet ink on its surface.

The flexibility of the ink layer after 3. curing is not good
The label after UV inkjet printing must be die-cut, slitting and other post-press processing. Therefore, the flexibility of the UV inkjet ink ink layer is required. If the ink layer is brittle and has poor flexibility, the digital label will have problems such as ink drop and irregular die cutting edges when die cutting and slitting. The main reasons are the following two points:

First, excessive curing.
because the UV inkjet ink curing is the ink by UV light irradiation, from the flow of liquid instant into a solid process. In this 1 process, if the power of the UV lamp is too large and the transmission speed of the printing material is slow, the UV light irradiation time is too long, which will cause the ink layer to increase brittleness due to excessive curing, resulting in yellowing of the printed surface, which will directly affect the flexibility and appearance characteristics of the digital label and adversely affect the subsequent processing.

second, UV inkjet ink composition problem.
The higher the functionality of the monomer in the UV inkjet ink, the more complex the three-dimensional network structure formed after the ink is cured, and the greater the brittleness of the ink layer. Therefore, in actual production, it is necessary to correctly select UV inkjet ink according to the conditions, and strictly control the curing conditions to avoid excessive curing.

UV inkjet ink caters to the digital label field of high efficiency production, energy saving and environmental protection and other development trends, since the beginning of the launch has been widespread concern. Some scientific research institutes and ink suppliers in China have also begun to devote themselves to the development of UV inkjet inks, but unfortunately, relatively mature products have not yet been launched, which also reflects that China still needs to improve in these 1 areas.