Influence of abnormal moisture content of the hott

2022-08-12
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The influence of abnormal water content of paper on printing quality

the process practice shows that there are many reasons that affect the printing quality, among which the abnormal water content of paper is also the reason that affects the printing quality of products. Therefore, a correct understanding of the relationship between the water content of paper and printing and an accurate control of the water content of paper play a crucial role in ensuring the printing quality

we know that paper is composed of fibers, fillers and adhesives. When the moisture content of the paper is excessive due to the change of ambient temperature to 2025, the binding force between fibers, fillers and adhesives in the paper is easy to reduce, which will inevitably affect the surface strength of the paper. In this way, during the printing process, it is easier to produce adverse conditions such as de dusting and paper dust, thus reducing the hardness and stiffness of the paper edge, and it is easy to produce unstable pre gauge positioning during paper feeding, which will lead to misregistration. On the contrary, if the water content of the paper is too low, the elasticity of the paper is poor, and the expansion rate of printing points and imprints is large. During the printing process, the paper is also prone to short wet absorption service life and inaccurate overprint

if the moisture content of the paper is uneven, various printing disadvantages will also appear. If the water content around the paper is about 1.4% higher than that in the middle, the overprint gauge line of the back trailing tip of the paper will be 1mm longer than its mouth; If the water content is higher than 2.5%, the back trailing tip of the paper will produce printing wrinkles, and the back trailing tip overprint gauge line will be 2mm longer than its mouth, and the corresponding overprint inaccuracy of pictures and texts in the printed sheet will also occur; If the water content is higher than 3%, the paper will appear Ruffle phenomenon, which will cause serious wrinkles during printing; If the water content of the paper is high and the relative humidity of the printing site is low, the four sides of the paper are easy to release water, so that the water content in the center of the paper is more than 2.5% higher than that in the four sides, the paper will produce tight edges, and it is easy to duplicate the pictures and texts in the middle during printing

various situations clearly show that whether the water content of paper is normal or not has a great impact on the printing quality. Therefore, when hanging the paper, you should first master the moisture content of the base paper, so that the moisture content of the center and four sides of the paper on the main forum after hanging and drying can be kept uniform. To this end, we should control the paper thickness of each clip. The graphic paper dryer used by our factory hoists about 70g/m2 of paper, and is designed to force it to flow through about 70 pieces of continuous fiber per clip. Basically, the air volume can be blown to the center through the paper gap, so as to achieve uniform blowing, so as to ensure that the moisture content of the paper is basically the same and ensure the printing quality

to sum up, the water content of paper has a significant impact on the printing quality. Controlling the water content of paper is a necessary measure to check the source of printing quality. It is of great significance to ensure normal printing and reduce the chance of printing failure and paper loss. In that case, what is the appropriate degree of water content control of the paper? Generally speaking, the moisture content of the paper is controlled between 7 ± 1%, and the moisture content difference between the center of the paper and the four sides is not more than 1%, which can basically ensure normal printing and avoid failures. (Kang qilai) (China Packaging News)

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