Pressure and adjustment methods in the hottest pri

Pressure and adjustment method in printing

no matter what kind of printing method, the correctness of printing pressure is very critical to the quality of products. Flexographic line, text printing is like this, flexographic line printing requires higher printing pressure. There must be a correct printing pressure in order to print exquisite and high-quality products

there are three printing pressures of flexographic printing machine. These three printing pressures will have a great impact on the printing quality of products, and they are indispensable. They are described as follows:

1. Pressure of inking device: this pressure is the pressure between inking roller and metal striped roller. Its main function is to control the ink consumption of printing and transfer the ink evenly. If the pressure between the two rollers is high, the amount of ink on the corrugated roller will be less; On the contrary, they eat more ink. At the same time, if the pressure between the two rollers is too small (i.e. the gap is too large), once the critical point of the grain height is reached, the function of the grain roller to transmit ink will be lost, resulting in uneven ink consumption of the printing part on the printing plate, and the ink volume is not easy to control during printing. Finally, the printing film of the printed product is too thick, resulting in drag and stick ink pollution, poor clarity, dot blurry paste, line spreading, and scratchy handwriting

this principle of printing pressure generally depends on the characteristics of the product, and the pressure between the two rollers of the line product can be relatively larger; Small text, line pressure can also be slightly larger; Large characters and field products can be relatively small

at the same time, the pressure is related to the size of the printing area. Generally, if the printing area is large, the pressure can be lighter to increase the amount of ink, so as to improve the field density, brightness and brightness. Generally, if the printing area is small or delicate, the pressure should be slightly larger to reduce the amount of ink and improve the printing clarity. This pressure must be horizontally tangent to both ends of the embossing roller without deviation, otherwise it will affect the clarity and printing effect of the printed matter

2. pressure of ink transfer device: the function of the printing pressure between the metal roller and the plate roller is to evenly transfer the ink on the metal roller to the printing surface of the plate (protruding printing part)

whether the printing pressure is correct or not has a great relationship with the point definition of printing. If the pressure is too heavy, the pressure of the embossing roller on the printing plate will be large, and the image points will expand after printing. (the word, line version becomes thicker or double shadow), the 1% point at the high-profile position can be expanded to 2% points, the middle adjustment point jumps up, the step level darkens and deepens, and the points at the low-profile level fall together. 6 it is used to evaluate the heat sealing strength at the fixed sealing position of the packaging bag film 1. The above points are almost on the spot

it can be observed from the magnifying glass that each dot is in an enlarged state of double shadow overlap (1 ~ 60%. More than 60% of the points can't be seen and counted, which is on the spot. In this way, the printed products have lost tone levels, poor image clarity, poor tone restoration, and the three colors cannot be balanced; At the same time, because the printing pressure is too heavy, the printing resistance of the printing plate decreases, and it is easy to pile ink, which will produce dirty and dirty spots during printing

so we take Rp0.2 as an example to discuss that the pressure is too light, and the printing plate can't eat ink, so of course it can't be printed. The best printing pressure: adjust the pressure at both ends of the corrugated roller and the printing plate roller to make it larger. 1. Before commissioning, you must check whether the line is intact and small, and make the ink layer on the corrugated roller just contact the circular cutting level of the printing plate surface. Of course, this "just in horizontal contact with circular cutting" can only be obtained after long-term operation practice

3. pressure of the embossing device: this pressure refers to the printing pressure between the printing plate roller and the embossing roller. This pressure is the last key to flexographic printing, which is directly related to the quality of prints, so that the ink layer obtained on the printing plate can be correctly transferred to the substrate

if the pressure between the two rollers is too high, the printed points are spread out, the middle color is light, and there are deep circles around, which has a great impact on the image level (the text and line version are spread and imprinted on both sides), the dark tone level is easy to be blurred, and if the pressure is too light, the image cannot be printed on the printing material

correct pressure adjustment makes the pressure at both ends of the impression roller and the plate roller consistent, and the two are in tangential horizontal contact. When the printing part of the printing plate is in contact with the printing material, the dots are basically not expanded, the words and lines are clear, the double printing is not spread, and the images are all printed. At the same time, in the printing process, it should be adjusted at any time according to the specific situation of printing. International standards or industry standards should be used to carry out physical property experiments of various materials to keep them in the best state

source: China tinplate printing