Kraft paper is a commonly used packaging material. Kraft paper printing can use flexo, gravure, offset, and screen printing processes. As long as you are familiar with the essentials of printing technology, familiar with the printability of printing inks and kraft paper, and you can select and deploy inks reasonably, and control equipment parameters, you can get the best quality of kraft paper printing. However, for some small packaging printing and processing factories, or small factories that have just started the production and operation of kraft paper packaging, due to various conditions, kraft paper printing still has some problems. Let's talk about the points that need to be paid attention to when printing kraft paper.
1. Pay attention to the color of printing
In order to get better color reproduction in kraft paper printing, it is more difficult than printing with SBS paper. Especially if you want to accurately achieve color reproduction on ordinary kraft cardboard, you need to be more careful than printing on bleached kraft cardboard. Since ordinary kraft paper is dark brown, the printing effect of ink on kraft paper is very different from that of bleached paper. Therefore, it is best to use brightly colored inks to print kraft paper, and use more eye-catching colors, so that the printing effect is better. If the selected ink is a soft color or a light color, it is difficult to achieve the desired printing effect.
2. Reasonable selection of ink
Kraft paper is different from SBS cardboard and general printing paper. It is uncoated, looser than bleached cardboard, and it has many pores on the surface and stronger permeability. Therefore, these characteristics of kraft paper require comprehensive consideration in ink application and coating. For example, based on the analysis of the characteristics of kraft paper, it is generally better to choose flexographic printing, rather than offset printing on kraft paper. This is because the kraft paper has rough surface, soft texture and strong ink absorption. In addition, the ink will pull down the paper fibers during printing.
3. Production and processing of kraft paperboard
Unglazed kraft paper is loose, porous and bulky. Therefore, it is easy to produce dust in the cardboard manufacturing process, so you should pay attention to prevent and reduce the harm caused by dust.
4. Die-cutting after printing
Because of the special structure and high strength of primary color kraft paper, it has better processing properties such as embossing, die-cutting and die-engraving. But for high-strength and tough kraft paper with primary color fibers, deep indentation lines are required to avoid rebound. And because of the high fiber strength of kraft paper, a narrower indentation is required on the perforated line.
5. Reasonable selection of kraft paper
In order to meet the new packaging needs of food manufacturers, raw kraft paperboard has some characteristics that are different from bleached paperboard. The original color of kraft paper is natural brown, with a healthy and retro charm. Since many foods packaging is designed for convenience or practicality, the strength of kraft paper is another advantage. In terms of practicality, kraft paper is better than homogeneous bleached paper.