Flexographic printing machine is a typical short ink supply system, the structure is relatively simple, mainly by ink tank, cots, scraping knife, and anilox roller four parts. Among them, anilox roll is the core of flexographic printing machine components, it is responsible for a uniform transfer to the printing plate of a certain amount of ink.
On the surface of anilox roller, there are many small concave holes with the same shape, which are called “Inking holes”. These holes play the role of ink storage, uniform ink, and quantitative ink transfer. Inked holes are generally carved along the axis into 45 ° direction, inked holes between the wall known as the “Net wall”, the area of the net wall with the shape of the ink hole.
Ink holes shape
several common shapes of inking holes include four-pyramid shape, four-pyramid shape, six-pyramid shape, trapezoidal cross-section oblique line shape, and additional channel inking hole, and so on. The opening degree and depth of the ink hole have a considerable impact on the ink transfer performance of the ink hole, the larger the opening degree, the deeper the ink transfer, the better the ink transfer; otherwise, the ink transfer is poor. In the above mentioned several kinds of ink hole shape, six-edge table-shaped ink hole has a larger opening, so its ink and ink-releasing performance are better, therefore, in the engraving roller often used this shape of ink hole.
Number of lines
The number of lines of an anilox roll is the number of inked holes per unit length of anilox roll, and it is also one of the important parameters of the anilox roll. Generally speaking, the higher the line number of anilox roller, the smaller the ink transfer, and vice versa. In addition, the line number of the anilox roll also determines its scope of application. In general, when printing large field color blocks or not too demanding image, you can consider using a low number of lines of anilox roll, such as in the printing field area can use 360 lines/inch anilox roll. On the other hand, when printing fine images or fine text and lines, a higher number of lines should be used on the anilox roll to prevent the serious enlargement of the hue value due to the small dot in Bloom’s area being immersed in the ink hole, or the thinnest lines get thicker. However, the number of lines of anilox rollers should not be too high. If the number of lines of anilox rollers is too high, it will not only cause certain difficulties to the processing technology of anilox rollers but also, as the thickness of the wall of high-line anilox rollers becomes thinner, the strength will decrease, it is easy to damage, that is to say, if the roller line number is too high, its service life will be correspondingly shortened. Generally speaking, the line number of anilox roller for printing live parts plus wire four or five times appropriate. Of course, it is also necessary to combine the actual production of printed images depending on the specific circumstances.
Printing layer pattern, text, lines, full-size coating, and halftone images, it is important to make clear the relationship between the number of roller lines and plates, roller lines should be higher than the number of plates 4 ~ 5 times, otherwise, the pattern on the dot will appear white or dot incomplete, resulting in color deviation, blur, and other printing failures.
Generally, the layer version of the selection of 700 lines/inches or more of the anilox roll, the field version of the selection of 300 ~ 400 lines/inches of the anilox roll, ink full thick; 250 line/inch, 600 line/inch or so roller suitable for glazing, on gold. When using a Flexography to print a layered version, the most difficult thing to solve is dot gain; with a higher number of lines on the anilox roll, the ink layer is thinner and the dot gain is easier to control.
Printing full size patterns, lines, text and other content, the selection of anilox roll is generally based on the size of ink supply to determine. For on-the-spot printing, if the line number of anilox roll is too low, ink supply is too large, printing plate on-the-spot edge of ink accumulation caused by double image; If two field overprint or printing area small field when you can choose some line number of high roller.
Printed text, line version, according to the size of the text, line thickness selection of the appropriate screen edition.
Different materials on the ink requirements are different. Non-absorbent printing materials (such as TO, PP, PET, aluminum foil, etc.) need few inks, roller wire number should be correspondingly higher; absorbent printing materials (such as paper, cardboard, etc.) need more ink, the number of lines on the anilox roll should be correspondingly lower.
CNY Label ribbon flexo printing machines were designed by our HK engineers who gained the technology patents. All the core parts use original import brands, and the mechanical accuracy can reach up to 0.08mm, good at multi-colors in small letters printing. Any quality problems or printing accuracy problems, we will be 100% responsible for it. If any interesting, please check our products page for the details.