How to deal with different materials of carton printing (top)

Common types of base paper used for corrugated cardboard paper are: cardboard, noodle paper, kraft paperboard, tea board paper, whiteboard paper and single-coated whiteboard paper. Due to the differences in the paper making process and the papermaking process of each base paper, the physicochemical indexes, surface properties, and printability of the above-mentioned base papers are greatly different. In the following, we will discuss the problems brought about by the above-mentioned procedure for the printing of corrugated paperboard inks for the above-mentioned paper products.

First, the problems caused by low-gram base paper

When corrugated cardboard is made of low-gram base paper, the appearance of corrugated marks on the surface of the corrugated paperboard may occur. It is easy to cause blemishes and can not print the required graphic content in the depression of the cymbal. For the unevenness of the surface of the corrugated cardboard caused by the dew, the flexible resin plate with good elasticity should be used as the printing plate to overcome the printing failure. Clear and exposed defects. In particular, A-type corrugated paperboard produced from low gram paper, the printing press will make the corrugated board's flat press strength is greatly damaged, and after the corrugated board passes the printing roll and the embossing roll, the side pressure strength will also be There is more damage.

If the corrugation surface of the corrugated paperboard differs too much, it may easily lead to the warpage of the corrugated board produced by the corrugated cardboard line. Warp cardboard will cause overprinting and printing groove irregularities in printing. Therefore, warp paperboard should be flattened and then printed. If you are forced to print uneven corrugated cardboard easily lead to rules. It also causes the thickness of the corrugated board to decrease.

Second, the original paper surface roughness problems

Printing on rough-surfaced, loose-textured raw paper, the ink permeability is large, the printing ink is dry fast, and on the surface smooth, high-fiber, tough, tough paper printing, the ink drying speed is slow. Therefore, on coarser paper, the amount of ink applied should be increased, and the amount of ink applied should be reduced on smooth-surfaced paper. Printing ink on paper that is not sized dries quickly, whereas printing ink on sized paper is slow drying, but the print pattern is reproducible. For example, coated whiteboard paper is less ink-absorbing than container board paper and tea board paper, and the ink is slow to dry, and its smoothness is higher than that of linerboard paper, noodle paper and tea board paper. Therefore, the resolution of small dots printed on it is high. The rate is also high, and its pattern reproducibility is better than that of noodle paper, cardboard paper and tea board paper.

Third, the original paper absorbs the problem of the arrival of differences

Due to the differences in papermaking raw materials and differences in sizing, calendering, and coating of base paper, the absorption energy differs. For example, when superimposing on single-sided coated whiteboard paper and kraft cards, the absorption rate is low and the drying speed of the ink is reduced. Slower, so reduce the concentration of the previous ink and increase the viscosity of the rear overprint ink. And put the lines, words, and small patterns on the first color printing, and put the full version on the ground in the last color printing. This can improve the overprint effect, and put the dark color on the front and the light color on the back. Overprinting errors can be covered, because dark color coverage is strong, is conducive to overprinting standards, and light-colored coverage is weak, even if there are running rules on the post-printing phenomenon is not easy to observe.

Different sizing conditions on the surface of the base paper also affect the absorption of the ink. The paper with small sizing amount absorbs ink more, and the paper with large sizing amount absorbs ink less, so the gap of each ink roller should be adjusted according to the sizing state of the paper, that is, the gap of each ink roller should be adjusted to control the printing plate. The amount of ink. From this, it can be seen that when the base paper is introduced into the factory, the absorption performance of the base paper should be inspected, and the printing slotting machine and ink distribution personnel should have a base paper to absorb the performance parameters so that they can dispense ink and adjust the equipment. And for the absorption of different base paper, adjust the ink viscosity and PH value.

Fourth, the problems caused by the difference in surface color of the base paper

The color difference between cardboard, liner, teaboard and whiteboard is large. Even if the same batch of whiteboard or single coated whiteboard is processed by corrugated cardboard, the speed of the production machine is different and the heat of the whiteboard is different. Different, the whiteness will also change, there will be a decrease in whiteness or grayed out; resulting in a difference in the whiteness of the same batch of products, and the whiteness of the printed white paper after printing with an offset press is still good Therefore, the white corrugated paper board processed by corrugated board line is used to print the ink on the ink machine. The selected ink is preferably a little deeper than the offset printing machine, so that the contrast of the printed pattern can be improved, and the color is also bright. In addition, even if the same type of the same company is used, different batches of base paper products may have different hue differences, such as whiteness of white paper, which is 75% or more, and whiteness of coated white paper is more than 75%. However, different batches of whiteboard paper will have the first partial blue, some yellow. In order to ensure the same color of your own batch of products, you should use the same batch of raw paper to print the same batch of products. However, when the number of raw papers in the same batch is not enough, even if different batches of raw papers are to be used, the color difference between the raw papers between batches and batches should also be taken into account, and the products printed in different batches of base papers should be marked to distinguish them. In order to ensure the consistency of the color of the molded product.

V. Problems caused by different moisture content

The different moisture content of the base paper affects the accuracy of the flatness and size of the corrugated board. Therefore, when corrugated board is produced on a corrugated cardboard line, the envelope area of ​​the base paper on each preheater and the production speed of the cardboard line are adjusted according to the moisture content of the base paper, and it is preferable to control the moisture content of the corrugated cardboard produced. 9%, in order to ensure that the corrugated board produced is smooth, the corrugated board has high hardness and good strength, otherwise, the strength of the corrugated board will be greatly lost after the printing machine is slotted. However, when the corrugated board is too dry and the upper printing press passes through the paper-guiding roller and the reel press line, it is easy to crush the inner paper, so the moisture content of the corrugated board should be strictly controlled.