[China Packaging News] Corrugated carton printing problems caused by unreasonable graphic design and flexible version production in the carton factory have occurred, which has seriously affected the carton pattern and printing effect. Let ’s talk about graphic design and Matters needing attention in flexographic plate making.
The carton factory needs to pay attention to the following when designing graphics:
1. Try to avoid full-page printing
When designing corrugated cardboard boxes, first avoid full-page printing in water-based flexographic printing presses, because when the corrugated cardboard boxes are designed to be full or when printing graphics around, the pressure between the printing plate and the pressure roller is because the platen roller is completely in contact with the corrugated cardboard The compressive strength of corrugated paperboard is destroyed a lot, and the wetting effect of large area ink on paper will also reduce the compressive strength of the carton. The physical performance index of corrugated boxes after full-page printing is reduced by about 30% . Therefore, the design of the corrugated cardboard box should be as simple as possible, and as far as possible to avoid printing graphics and text on the entire corrugated cardboard layout, not to print the full version. If some cartons need to be printed in full version, the color set should not be too much, and the printing pressure should be as small as possible while ensuring the printing effect. For large quantities of cartons, other printing processes should be selected. The application of the pre-printing process of corrugated boxes in the domestic corrugated box industry is an ideal solution for full-plate printing, and can achieve accurate multi-color overprinting.
Second, reduce the number of overprints
The more overprinting times, the more severe the carton compressive strength declines, so the number of overprinting should be reduced as much as possible. Especially for the accurate overprinting of smaller patterns, because the infiltration of water-based ink on the surface of the corrugated carton will seriously affect the effect of the overprinting edge, especially when the offset printing carton products are used for water-based flexible printing, the corresponding color of the overprint should be changed according to the water-based flexographic printing process. . The pursuit of green packaging and saving packaging is actively advocated by many international companies. The simple, bright and creative pattern design can not only display the information of packaging products, but also save packaging resources and reduce production costs. Therefore, in many corrugated carton product packaging, the number of overprinting is reduced, and the physical performance index of corrugated carton packaging is greatly improved. On the other hand, there are many overprints, the color reproduction effect on the corrugated carton is not very good, and the production cost of the carton with multiple overprints is also very high.
3. Avoid text with small print size
There is no problem in making small text on the flexible resin plate, but from the perspective of the effect of the promotion of the product, the corrugated cardboard box should try to avoid printing small characters. Such as the size of text below 50px , it is almost impossible to see clearly at a distance of more than 5m , so that it loses the significance of promoting and selling products. The printing times of printing plates with smaller text will also be greatly reduced, and it is more difficult to handle the printing operation. The printing pressure is light, and the text is relatively shallow. On the one hand, increasing the printing pressure will cause the dots to deform, and the text and lines will have an obvious " edge effect " . On the other hand, the corrugated structure will be damaged, reducing the strength of the carton. Therefore, the graphic design of the carton should avoid small print as much as possible.
4. Avoid banding (that is, the same direction as the corrugated cardboard machine) printing
Some carton patterns have horizontal gradient lines. This area of ​​the carton is most likely to be broken during printing. The printing pressure will crush the corrugation, so ribbon printing should be avoided.
5. Use inks with large color saturation and strong tinting power
For some carton samples with brighter colors, the ink color to be used must be eye-catching. Since the color of the corrugated cardboard itself is quite dark, you should try to use ink with large color saturation and strong coloring power (such as big red), otherwise the printed color will be very different from the desired color. I think the color of the proofs will be as unrealistic as what you see on the monitor or the sample printed by the inkjet machine.
6. Relax the pressure range of the flexible board on the corrugated board
When designing patterns with small gradient dots, consideration should be given to the technological arrangement of the plate number of lines to be higher, the color of the deep plug-in network and the number of light-colored plug-in network lines. In the design of flexographic dots, the factors of printing machine accuracy must be considered. The pressure range of the flexo to the corrugated cardboard should be relaxed, and the ratio of the number of printing plate lines to the number of anilox roller lines should be reasonably selected.
7. Reasonable design of opening pattern
The position of the handle hole on the carton should be designed as far as possible in the middle position, and the reasonable opening type should be considered in the design.
8. Avoid large differences in printing patterns on the same layout
The layout of the carton should be avoided on the same layout as the large area of ​​the field and the dots.
Nine, consider the elastic deformation of the flexible board
Because the flexible plate has elasticity, after being installed on the plate cylinder, the plate will bend and deform in the circumferential direction of the cylinder, but will hardly deform in the axial direction of the cylinder. This deformation changes the size of the printed text. For the more demanding prints, measures must be taken to compensate, and the best way is to change the size of the graphic on the printing film. If there is a circular pattern on the original, you can use the deformable mirror to shoot according to the calculated compensation factor. The compensation factor is the reduction factor of the printing film, that is, the percentage of the graphic size of the printing film in the printing direction.
Ten. Ensure that the sample products are consistent
The same sample should be kept when the graphic design is output, to avoid the difference of the output of different printers, which causes difficulties in inspection and judgment.
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