How to solve the problem of white spots in the process of self-adhesive label printing
Printing white spots is a common problem in the printing process of self-adhesive labels. Mr. Qiang Yongsheng, technical service manager of Dongguan Ande Label Material Co., Ltd., based on the experience collected from customers over the years, summed up the reasons for the occurrence of white spots in the printing process of self-adhesive materials, and put forward corresponding suggested solutions. share.
Generally speaking, there are four main reasons for white spot problems in printing: rough label material, powdered material, static electricity, and dust in the workshop environment. This article will give solutions to the above four problems.
1. White spots caused by rough surface of the material
At present, in my country, the printing of self-adhesive labels is mainly based on letterpress printing and flexographic printing. These two printing methods have high requirements on the surface roughness of the self-adhesive material. For example, for the surface material of coated paper, if offset printing is used, the surface roughness (the height difference of the material surface) can be less than 1.4 microns; but when using letterpress and flexographic printing, the surface roughness needs to be less than 0.7 microns to ensure the printing process There are no white dots in it. This is because the printing pressure of the latter two printing methods is much smaller than that of offset printing. If the surface of the self-adhesive material is not smooth enough, the surface of some materials will not be printed with ink, resulting in printing white spots. This phenomenon is especially prone to occur in the process of printing large-area dot graphics. Observed under high magnification, it is characterized by the complete absence of ink in the white spot area. This is because the white point area is lower relative to other areas, and the ink on the plate is not transferred to the surface of the material. Another obvious feature is the printing white spot caused by the surface of the material is not smooth enough, that is, the white spot is often very large, and in most cases it spreads over the entire plate, which is very obvious. This is because the white point area is lower relative to other areas, and the ink on the plate is not transferred to the surface of the material. Another obvious feature is the printing white spot caused by the surface of the material is not smooth enough, that is, the white spot is often very large, and in most cases it spreads over the entire plate, which is very obvious. This is because the white point area is lower relative to other areas, and the ink on the plate is not transferred to the surface of the material. Another obvious feature is the printing white spot caused by the surface of the material is not smooth enough, that is, the white spot is often very large, and in most cases it spreads over the entire plate, which is very obvious.
When encountering this printing white point problem, we can solve it in the following ways:
1. Replace qualified materials. If the surface of the self-adhesive material is not smooth enough, it is a material quality problem. We can ask material suppliers to replace materials that meet production standards.
2. But according to the author's understanding, in most cases, the replacement of materials cannot guarantee the construction period, because the production cycle of self-adhesive label printing enterprises is quite tight. Also, the printing house requires a series of preparations to change jobs. Once there is a problem with the material and cannot be printed, the preparation work will be wasted, which will seriously affect the production efficiency of the printing factory. If this is the case, we can consider printing a primer or thinner (remover) on the surface of the material first. These two printing auxiliaries are basically colorless and have little effect on the color of the printed matter. After printing these two additives, the surface of the material will be filled to artificially improve the smoothness of the material.
