How to adjust the control cardboard displays printing pressure
Regardless of the printing method, the correctness of the printing pressure is critical to the quality of the product. Flexographic lines, text printing is like this, flexo screen printing requires more printing pressure. Be sure to have a correct printing pressure to print beautiful, high-quality products.
There are three printing pressures for flexographic printing presses. These three printing pressures will have a great impact on the printing quality of the products. They are all indispensable.
1. Pressure of the inking device: This pressure is the pressure between the inking roller and the metal anilox roller. Its main function is to control the amount of ink consumed in printing and to evenly transfer ink. If the pressure between the two rolls is large, the amount of ink on the metal anilox roll is small; otherwise, the amount of ink consumed is large. At the same time, if the pressure between the two rolls is too small (that is, the gap is too large), once the critical point of the height of the mesh is reached, the effect of the ink transferred by the anilox roller is lost, resulting in uneven printing of the printing portion on the printing plate, and ink during printing. The amount is not easy to control, and finally the printed product film is too thick to produce drag-and-stick ink, poor definition, dot-dummy, line spreading, handwriting and other defects.
If the pressure of the two rolls is too tight (small gap), the amount of ink on the metal anilox roller is relatively reduced, the dots can be printed clearly, and the words and lines can be printed clearly and crisply, but lack a certain amount of ink and gloss. At the same time, it is necessary to prevent the metal anilox roller and the inking roller from being bent at both ends due to excessive pressure between the two rollers, the printing machine gear is beating, and the teeth are broken.
The principle of the size of the printing pressure should generally depend on the characteristics of the product. The pressure between the two rolls of the wire product can be relatively large; the small text and the line pressure can be slightly larger; the large characters and the field products can be relatively small.
At the same time, the pressure is related to the size of the printing area. Generally, the printing area is large, and the pressure can be lighter to increase the amount of ink, thereby increasing the density, vividness and brightness of the ground. Generally, the printing area is small or relatively fine, and the pressure is slightly larger to reduce the amount of ink and improve the definition of printing. This pressure must be horizontally tangent to both ends of the anilox roll, and there should be no deviation, otherwise it will affect the sharpness and printing effect of the printed matter.
2. Pressure of the ink transfer device: The function of the printing pressure between the metal anilox roller and the plate roller is to uniformly transfer the ink on the metal anilox roller to the printing surface of the printing plate (protruding printing portion).
The correctness of this printing pressure has a great relationship with the sharpness of the printed dots. The pressure is too heavy, the pressure of the anilox roller on the printing plate is large, and the image dot after printing is enlarged. (word, line version becomes thicker or double shadow), high-profile 1% network point can be expanded to 2% network point, the middle adjustment network point jumps up, the tone level becomes darker and deeper, the low-key level network points fall off, 60% to the Internet point almost For the field.
It can be observed from the magnifying glass that each of the dots has an enlarged state in which the double shadows overlap (1 to 60%). 60% of the Internet points have been invisible, and they are solid. The products printed in this way have a loss of tone level, poor image definition, poor color tone reduction, and three colors cannot be balanced. At the same time, due to excessive printing pressure, the printing plate printing rate is reduced, and it is easy to stack ink, which will be generated during printing. Draws and dirty spots and other drawbacks.
The pressure is too light, the ink on the plate cannot be printed, and of course it cannot be printed.
Optimum printing pressure: adjust the pressure between the anilox roller and the plate roller to the same size, and make the ink layer on the anilox roller just in contact with the plate surface. Of course, this “just in contact with the circular cut” is subject to long-term operational practice.
3. Pressure of the imprinting device: This pressure refers to the printing pressure between the plate roller and the platen roller. This pressure is the last key to flexographic printing in order to transfer the ink layer obtained on the printing plate to the printing material correctly. It is directly related to the quality of the printing.
The pressure between the two rollers is too large, the printed dots are spread, the middle color is shallow, and the surrounding circles are deep circles, which have a great influence on the image level (text, line version spreads the footprint bilaterally), the dark tone level is easy to blur, the pressure is too much Light, no image can be printed on the substrate.
The correct pressure adjustment ensures that the pressure between the platen roller and the plate roller is adjusted to be the same, and the two are in a circular and horizontal contact. When the ink-printing surface of the printing plate is in contact with the printing material, the dots are basically not enlarged, the words and lines are clear, and the double-printing is not spread, and the images are all printed out as the best. At the same time, in the printing process, it is necessary to adjust it at any time according to the specific conditions of printing to keep it in the best condition.
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