Exposure in the printing of the hottest carton

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Editor's note: with the rapid development of packaging unemployment, users have higher and higher requirements for the quality of corrugated boxes, including the printing quality of selling cartons. If the printing technology is not well mastered, there are often many printing failures, such as "bottom exposure" and "white spots" in the field of printing. In view of the many variables that cause the above problems, the following is a simple analysis from the factors of materials, processes, plates and so on

I. reasons for printing materials

1. The poor smoothness of face paper and paperboard is the most fundamental reason for the problems of "false printing", "bottom exposure" and "white spots"

the smoothness of the face paper itself is poor, or the smoothness of the paperboard itself is poor due to factors such as large amount of glue or light or heavy "washboard" when the paperboard is compounded. During printing, the surface of the printing board cannot be in full contact with the face paper, so that the connecting material in the ink cannot completely fill the paper gap. When the face paper is printed on white paper, white holes will appear, resulting in "bottom exposure" and "white spots"

in order to solve this problem, some manufacturers often use the method of increasing the printing pressure, but this will produce great side effects: on the one hand, it will lead to point deformation, and obvious "edge effect" of words and lines; On the other hand, the corrugated structure will be damaged, reducing the strength of the carton. Therefore, according to the specific requirements of customers for paperboard, choosing facial paper with different smoothness and controlling the process factors of forming "washboard" during paperboard production are the fundamental methods to solve "false impression", "bottom exposure" and "white spots"

2. Under the combined action of printing pressure and ink, the coated layer of face paper will produce paper wool, which will often also cause "false impression", "white dot" and other phenomena

solution: for cartons with high requirements, choose paper with high surface strength; Avoid large areas of the field during layout design; According to the surface condition of the paper, adjust the speed of the printing machine and the viscosity of the ink during printing, so as not to make the surface paper roughen, which avoids the generation of "white spots" by using computer measurement and control technology in the packaging bag pressure testing machine proposed by Shandong Sida high tech

II. Technological factors

in the carton production line, when trimming the burr with a single knife, the knife is cut from top to bottom, which often leads to the uneven edge of the cardboard surface 179 steel pipe paper used for construction scaffolding. When full page printing is carried out, the edge print cannot appear "exposed" or "false impression". Increasing pressure during printing and ensuring sharp knife edge during trimming can reduce this phenomenon, but it cannot be completely eliminated

III. plate materials pay attention to the factors of germanium, lithium and zirconium small metal varieties with high prosperity in the industry

the printing plate of carton printing machine usually adopts rubber plate and flexible resin plate (including domestic or imported), and there is a certain gap between the elasticity and inking ability of the two. Generally, the elasticity and inking ability of flexible resin plate are higher than that of rubber plate. The printing ink layer is relatively thick, and generally there will be no "false impression", "bottom exposure", "white spots" and other faults

the poor flatness of the printing plate surface causes the difference in the inking amount of the plate, and the imprinting will also appear "bottom exposure" and "white spots" that are closer to the market demand of steel structures

generally, the flatness of the surface of the flexible resin plate is better than that of the rubber plate, so for cartons with high printing requirements, large area of field or a little printing, the flexible resin plate must be selected for printing

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