Analysis of reducing material consumption by using

2022-08-13
  • Detail

Analysis of reducing material consumption by using thin ink flexographic printing

flexographic printing (hereinafter referred to as flexographic printing) has developed rapidly with its advantages of low cost, high speed and high efficiency. An important reason for the low cost of flexo printing is the thin ink layer. At present, in all printing methods, the ink layer of flexo printing is the thinnest, and the imported motor drives the high-precision ball screw. Next, the author analyzes the influence of ink layer thickness on print quality and achieving the best ink layer to reduce costs:

first, ink

ink is composed of pigment, binder and auxiliary agent. Due to the thin ink layer of flexo printing, its ink is different from offset printing ink. Flexographic ink requires high concentration, poor fluidity, high viscosity and other characteristics. Therefore, the ink with thin ink layer should have high concentration of pigment and low concentration of medium. Among the components of ink, pigments are the most expensive, while others such as water, solvents, fillers and diluents are relatively cheap

the purpose of printing is to use an ink layer containing a certain amount of pigment to obtain the required color. If we use a thin ink layer in the printing process, in order to achieve the same color effect as the thick ink layer, we must have the same pigment as the thick ink layer. The profit of thin ink layer is mainly from reducing ink waste and saving ink supply. If the ink layer is very thick, the pigment concentration should be diluted, otherwise the color is too dark. If the color of the print is too dark, it means that you have to waste some money, because under normal conditions, you need to use more ink to present the ideal color

second, the shape of the hole and the amount of ink

in the process of flexo printing, the short ink path is its remarkable feature. The corrugation roller is the key component to ensure the ink transfer and uniformity quality in the short ink path. The function of the corrugation roller is to quantitatively and evenly transfer the required ink to the graphic part on the printing plate. In the process of offset printing, the rubber drum is used to supply ink, which has a large amount of ink, making the ink layer thickness of offset printing greater than that of flexo printing. However, if the wrinkle roller runs fast, although you use the doctor blade to scrape the ink, its ink supply will be the same as using the rubber roller, and the ink supply will be too large. Therefore, we usually use low-speed corrugated rollers, which can make the thin ink layer have a smooth surface

however, in the process of thin ink layer printing, it is not enough to use only low-speed corrugation rollers, and the smoothness, shape and structure of holes are also very important. The extension change of the surface of the ceramic roller has no great effect on the adhesion change of the ink. On the embossing roller, the ink in the hole can be separated from the hole by itself. Of course, the shape of the hole will affect the separation of ink. Usually, the amount of ink separated from different hole shapes is also different. Generally, when hexagonal acupoints are used, the smoothness of acupoints is required to be high. At the same time, there are corresponding requirements for the depth of acupoints. It is required that the hole carving should not be too deep. If a hole carving is too deep and the surface of the hole is not smooth enough, the ink cannot flow out of the hole and the normal ink layer separation cannot be carried out. So that the printing quality can not meet the requirements

III. overprint and ink layer

drying system is an indispensable device on the printing machine. If the ink layer is thick, the print is not easy to dry. The corresponding printing speed cannot be improved, and the printing cost will rise. And in the printing process, the ink drying will make the ink peel off from the substrate, so that the printing plate gets dirty. The main reason is the poor overprint effect of the impervious ink. Overprint refers to printing the second color ink on the first color ink to form the third color, such as magenta 2 Experimental force grading: stepless speed regulation ink is printed with yellow ink to form a warm red color, or green ink is printed with yellow ink. If the first color ink is not dry, the second color ink is easy to form spots on the first color ink when overprinting. In this case, it is necessary to use more yellow ink to form red or green to achieve the ideal color effect. In general, it is impossible to accurately predict the impact of poor overprint on color rendering. If the ink layer is thin, the ink is easier to dry and the overprint effect is better

IV. printing tone, detail and ink layer

flexo printing is to copy the original with many dots of different sizes. Among them, high light and extremely high light areas are copied with low percentage dots. Dark areas are printed with a high percentage of dots

a wide tone has a more refined level. Because the thick ink layer enlarges the dots more seriously, thus compressing the tone, there is not enough hierarchy when copying a good image, and the printed matter is flat and lusterless. The thin ink layer, dot expansion size, has a wide range of tones, so it can copy the original well

we know that to get a thin ink layer, we should first determine its optimal value, and then determine the optimal ink layer

① how to choose the best ink layer thickness? First of all, consider the ink performance and the amount of ink supplied by the corrugated roller, as well as the empirical value of the ink layer on the substrate. The test of the number of lines of the wrinkle roll should be carried out with high concentration, poor fluidity and high viscosity ink. Under a given standard low-speed corrugation roller, a series of tests are carried out on the surface of the corrugation roller with different number of engraving lines, and finally the best number of lines of the corrugation roller is obtained. The corrugated roller selected by this test method is more scientific. Different engraving frequency bands show different effects on the surface of the embossing roller. This kind of corrugated roller is usually called band corrugated roller by introducing the energy storage technology of vanadium flow battery. Generally, the wrinkle roll is selected by the number of lines. Since the function of the corrugation roller is to quantitatively and evenly transfer the amount of ink required to the graphic part on the printing plate, the best ink layer is also determined after the selection of the best corrugation roller

however, we should also consider the saturation Novak of the color of the thin ink layer. In addition, there are printing quality issues that should also be taken into account. For example, the fuzzing of paper, the fuzzing of field printing, small white dots and lines are too hard. Thick ink layer can cover up these problems, thus endangering the following process. The thin ink layer can immediately find these problems, and then can be solved in time. Therefore, when choosing the best ink layer, we should consider the print quality, especially the saturation of the print color

② reduce printing failures. Thin ink layer is very beneficial in reducing printing failures. Many dirty spots in printing come from excessive ink. Thick ink layer, with a large amount of ink on the dot, makes the ink flow and dot connection. This situation is most obvious in the image of the middle tone part, which will form halo and other phenomena. The reason for this phenomenon is that the expansion of the intermediate adjustment point is the largest. If it is a thin ink layer, the amount of ink on the dot is small, and there is not enough ink to expand around the dot, so the dot expands in size, so it is not easy to rub dirty when the printing plate is separated from the substrate, and it is not easy to form dirty spots

although the middle tone is difficult to control, the high light tone should also clear the sample at low speed. The number of high-speed lines, low-speed operation of the Striped roller, the inking hole on the Striped roller is small and shallow, and the shallow hole gambling ink amount is small, thus forming a thin ink layer. The wrinkle roller with small holes and high-line number has a thin wall, which makes the ink layer smooth and the ink transfer convenient, so that the problem of small white spots on prints can be solved

③ reduce production costs. The thin ink layer makes the printing operation easier. In the process of flexo printing, the low-speed corrugation roller is used to print a thin ink layer, so the ink supply is better controlled, so the probability of ghosting and ink accumulation is small, and the dot expansion is not significant. At the same time, in the process of flexo printing, the thin ink layer is not easy to rub the printing plate, which can reduce the times of cleaning the printing plate, thus saving a lot of time for cleaning the printing plate, so it can improve production efficiency and reduce production costs

④ little environmental pollution. In today's world, air pollution has an increasing impact on people's physical and mental health. We cannot ignore the impact of ink volatilization on the environment. Under normal circumstances, we believe that thin ink layer, less solvent volatilization in the ink, and little ink on the printing plate, substrate and roller. Therefore, the thin ink layer has little environmental pollution. To sum up, the use of thin ink layer in flexo printing is the general trend, and we should actively promote it. It not only contributes to environmental protection, but also brings huge profits to printing enterprises

source: keyin

Copyright © 2011 JIN SHI