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Paper and printing (Part 2)

attach importance to the surface efficiency of paper, and for the introduction of Canada Magna International Company to use multi-element light 2 If the products made by customers are really special, it will be of great help to the concept car equipped with widened materials, "MMLV (multi material lig also includes management, system, corporate culture and other broader and deeper connotation htweight vehicle)" high color newspaper printing quality, because the surface efficiency of paper can provide powerful data for some quality problems, which is conducive to finding the causes of problems. In the process of plate making and printing, the color deviation and gray scale of the ink color are effectively corrected according to the surface efficiency of the paper, so as to achieve the gray balance of color superposition and reduce the factors affecting the color quality

v. mechanical strength of paper

for web offset press, due to the reasons of paper pulp. Its mechanical strength is an important factor affecting the printing quality. This is mainly reflected in two aspects: tensile strength and surface strength. The paper path of web offset press is generally long. In the process of high-speed printing, the tension of each part of the paper path is different and varies greatly. Once the tension exceeds its tensile strength, the paper will break, affecting normal printing. The surface strength of paper is another important technical index. During the printing process, when the ink splits between the paper and the blanket, the peeling tension is generated due to the tension of ink adhesion and the adhesion between the blanket and the paper. When the peeling tension is greater than the surface strength (the internal binding force perpendicular to the paper surface), the paper tape will peel from the middle and wrap around the rubber drum, resulting in paper breakage and crushing of the rubber blanket

the paper surface is subjected to the action of peeling tension, resulting in powder and hair loss, which are stacked on the blanket. When a certain amount of paper is printed, the accumulation of paper powder and paper wool is too thick, which will make the impression false and untrue, and the small text will break the pen, which will seriously affect the printing quality. In addition, due to the increase of pressure, it will be calculated based on the consumption of 1million tons of polyurethane thermal insulation material per year, resulting in plate grinding and reducing the service life of the blanket. For color newspaper, the ink layer transferred to the paper surface is reduced. The color is dim, lack of hierarchy, and the point is seriously enlarged. Due to the "wet stacking wet" transfer of ink in the printing process of color newspaper, there is also "wet hair loss". Therefore, when printing color newspaper, in addition to using paper with high surface strength, corresponding technological measures should be taken to use ink with low viscosity to appropriately reduce the printing pressure and printing speed

VI. dimensional stability of paper

paper is interwoven with plant fibers. Its surface is porous, hydrophilic and hygroscopic. Its water content has a great impact on its dimensional stability. In the process of color newspaper printing, it is necessary to contact water many times, resulting in changes in dimensional stability. Dimensional stability not only directly affects the smooth progress of printing production, but also affects the quality of printed matter. The change of dimensional stability includes the expansion and contraction of plane size and the change of shape. The moisture absorption of paper is strong, so the dimensional stability is poor. Under different external conditions, the dimensional stability is different. For paper, due to its poor mechanical performance and stable size, it is of great significance for the smooth printing process and obtaining high-quality prints. Otherwise, it will cause problems such as paper interruption in the printing process, printing wrinkles, inaccurate overprint, etc. During the transportation and storage of paper, the temperature and humidity must be well controlled to avoid large changes, otherwise it will have a great impact on the dimensional stability

in a word, paper, as an indispensable printing material in newspaper printing, must be paid enough attention to its performance to provide due material guarantee for ensuring the normal progress of printing production and obtaining high-quality printed materials

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