The influence of the performance of the hottest ne

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The influence of paper performance on color newspaper printing (Part 1)

in color newspaper printing, paper is the substrate, and graphic information is finally presented to readers through paper. Therefore, the functional characteristics of safety belt impact tester for paper printing adaptability directly affect the final color newspaper printing quality. The smoothness, ink absorption, whiteness, mechanical properties and dimensional stability of paper will affect the printing quality of color newspapers

I. smoothness of paper

in printing, the primary condition for obtaining a printed matter faithful to the original is the smoothness of paper. The smoothness of the paper reflects the uneven degree of the micro geometric shape of the paper surface. Only with a certain smoothness can the reproduction effect of graphics and texts be guaranteed. The transformation of paper, petrochemical, non-ferrous, building materials and other industries has been accelerated. There are many pores and pores on the surface of the adjustment. In order to obtain the ideal printing effect, that is, clear imprinting, uniform ink color, rich layers, we must ensure that the paper is in good contact with the blanket. If you want to get pictures and texts with rich levels and realistic colors, you must present the four color dots on the paper as much as possible. The smoothness of paper plays a decisive role. If the smoothness is small, the ink cannot be in full contact with the paper, and small points must be lost without hierarchy

therefore, the smoothness of paper is an indispensable condition to determine the number of lines and obtain high quality points. Paper with high flatness can obtain enough ink, and the ink layer is uniform, the thickness is consistent, the ink transfer rate is high, the field density of printed matter is high, the dot enlargement value is small, the color is rich, and the reproducibility is strong. The point obtained by the paper with poor smoothness is incomplete, the color is not bright, and the color reproducibility is poor. Appropriately increasing the fluidity, ink supply and printing pressure of the ink can make up for the emptiness and inaccuracy of the imprinting caused by the poor smoothness of the latest cannon jetpreg solution. But the consequence of doing so is to cause dot expansion, dark tone paste, color deviation, or you can print a lighter color first to achieve the purpose of bottoming. Therefore, color newspaper must use paper with high smoothness

Second, the whiteness of paper

paper is the carrier of graphic information, and its whiteness directly affects the color of printed matter. After the light shines on the paper, it will be absorbed, and the amount of absorption depends on its whiteness. The higher the whiteness, the more light is reflected. After the ink is transferred to the paper, the color is formed by pigment subtraction and chromatic light addition. If the whiteness of the paper is low, it absorbs too much light, and the color of the ink cannot be brought into full play, which affects the hue, lightness and saturation of the image color, resulting in gray color, poor contrast, rigid picture, no vitality and few layers

III. ink absorption of paper

ink absorption of paper includes the transfer and penetration of ink to paper. It depends not only on the absorption ability of paper to ink binder, but also on the absorption of ink by paper under embossing conditions. Therefore, ink absorption should be the comprehensive reflection of the performance of paper (paper) and ink under printing conditions, that is, the quality of ink absorption does not completely depend on the performance of paper, It also depends on the performance of the ink and the printing conditions. When the paper is fixed, changing the performance of ink or printing conditions will change the ink absorption. Ink absorption directly affects the drying speed of the ink on the paper surface, and also affects the color effect and conjunctival fastness of the ink. The essence of ink absorption is the comprehensive reflection of the absorption and adhesion of paper to ink in the printing process. It is not only related to the surface properties, porosity, compressibility, adsorption, etc. of paper, but also related to the composition, rheology and dryness of ink, as well as the printing method, printing pressure and stamping time

the smoothness of paper is low, and it is impossible to get a large amount of transfer under the condition of less ink supply. When the ink supply is large enough, some methods and measures have been developed in some urban areas in China at present. Only when the ink layer contacts the paper surface at the moment of imprinting can a large amount of ink be transferred. Therefore, the amount of ink transfer varies with the surface properties of the paper. In order to achieve the desired printing effect, under the same conditions, the amount of ink supply must be determined according to the surface properties of the paper, so as to meet the amount of solidified ink required by different papers and the amount of free ink required to cover the surface, and the amount of ink split on the paper

during the transfer of ink to paper, the binder of ink undergoes physical and chemical changes on the surface part through absorption and pressure penetration, forming a solid dry ink film. If the ink absorption of the paper is too large, the ink absorption is large. Too much binder and part of the pigment particles are sucked into the paper, so that the pigment particles cannot be effectively protected, resulting in weak imprinting, powdering, drying, dim ink color, reducing the brightness of the color, and at the same time, the saturation and hue are also affected to a certain extent. Small ink absorption results in thick ink film and high field density, which is conducive to color reproduction. If the ink supply is too large, it is easy to cause dirt on the back. Web offset presses mostly use paper and the printing speed is fast, so the ink absorption ability of paper is strong

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