Selection principle of anilox roller in carton printing

The amount of ink transferred by the anilox roller is generally measured by the number of lines (line/inch). When the number of screen lines is low, the amount of ink transferred is large. When the number of screens is high, the amount of ink transferred is correspondingly reduced. For example, a 150 line/inch anilox roller has a larger ink transfer volume than an 300 line/inch anilox roller. It should be noted that the number of lines of the anilox roller and the number of lines of the plate are two different concepts. The network cable on the printing plate is a layered halftone, referring to the high network cable for the image fine product. The size of the dot network has high light, dark tone, and fine pitch, and the mesh size of the anilox roller is the same. To print quality prints, you must choose the right anilox roll.
1. According to the selection of printing materials, the appropriate anilox roll printing materials include paper, plastics, and metal films. The amount of ink sucked by the paper is large, and the ink on the paper is mainly absorbed by the paper. There are many different types of paper, such as corrugated paper, writing paper, forest paper, adhesive paper, etc., and the amount of ink suction is also different. Plastics and metal films have no absorption of ink, and the drying of ink depends mainly on volatilization. Different substrates have different ink requirements. The amount of ink used in kraft paper printing is used in plastic printing. The problem of excessive ink and dryness occurs, or millions of prints are dirty; otherwise, the amount of ink used in plastic printing is used in the printing of kraft paper. Causes the ink on the print to appear white. General product printing materials and the corresponding number of lines of anilox roller are listed in Table 1.
Table 1 Number of Rolled Lines for Different Printing Materials Reference Values ​​Material Name Number of Anilox Rolls (inches)
Corrugated 120 to 150
Writing paper newsprint 150～180
Dowling Paper 180～200
Sticker paper 180～220
Plastic metal film 200~250
2. In accordance with the print flag, select the number of anilox roller print graphic text, lines, ink blocks and halftone images. Text, lines, and thick lines with small words and fine lines. Different images and texts cannot use the same amount of ink. Therefore, the number of anilox roller lines must be properly configured. For example, although the amount of ink absorbed by newsprint is relatively large, newspapers printed on newsprint are generally more textual (most of them are small prints). Therefore, the amount of ink required is small, so an anilox roller with a higher number of lines should be selected. Similarly, printing half-tone prints also requires less ink and more anilox roller lines. Can be 250 ~ 300 lines / inch anilox roller, the effect is generally very good.
3. Select the number of anilox roller lines according to the number of printed images. Modern flexographic printing is gradually maturing due to materials, anilox rollers, inks, and brushing machines, and the prints are also developing to color printing, and the quality is also very good.
When printing color images, there are special requirements for the number of anilox roller lines. In the past, it was generally considered that the ratio of the number of lines of the printing element to the number of anilox roller lines was 1:3, and now it seems to be further developed. It is generally considered that the ratio of the two is suitable for 1:3.8, and some are 1:4.5. Why are the two proportional? What is the right proportion? People are exploring. Found that the proportion is too small, the print will produce a moire, 1:2.5 or more is more secure. Printed cable printing products when the amount of ink absorption is less, in the plastic printing general print, anilox roller line number of 200 ~ 250 lines / inch, halftone screen printing version will have to choose a higher number of lines anilox roller. According to some data, it is appropriate to have a plurality of cells on the anilox roller to cover a dot of the printing plate when the dots on the printing plate do not allow sufficient ink. Because the anilox roller consists of hundreds of thousands of cells with the same shape, the concave part stores and transmits ink, and the convex part (wall) is theoretically free of ink, accounting for 31% of the calculated network wall. There must be multiple cells covering one dot of the printing plate, otherwise the high-light dots (such as 10% of dots) will not get ink if they fall on the wall, and the printing quality is poor. In order to get ink from the high light outlets, the ratio of the printing plate to the anilox roller is 1:3. The best condition for a 1 percent dot is that it is covered by only one dot, and it is covered by 1.6 dots at 1:4, 1:5. It was covered by 2.5 nets. Other number of outlets cover more network points.
When determining the number of lines of the anilox roller must not ignore the ink, if the printing material is a non-absorbent material, the ink demand is less, can make the ratio of plate lines to the number of anilox roller lines 1:4.5; for strong absorption The printing material, the ratio of the number of printing plate lines and the number of anilox roller lines may be 1:2.5, otherwise the ink amount is not enough.
In short, when performing screen printing, it is necessary to reasonably select the net shape of the roller, and the amount of ink collected by the net should be as large as possible. (Yin Jinhua) (From "Paper Packaging")