The influence of the hottest ink factor on the glo

The influence of ink factors on the gloss of printed matter

the ink factor affecting the gloss of printed matter is mainly the smoothness of ink film, which is determined by the nature and quantity of binder. The ink should contain fine pigments that are evenly dispersed, and have sufficient viscosity and fast drying speed to avoid excessive penetration of binder into the pores of the paper. In addition, the ink should also have good fluidity, so as to form a smooth ink film after printing

1. Influence of ink film thickness on the gloss of printed matter

after the paper absorbs the binder of ink to the greatest extent, the remaining binder remains in the ink film, which can effectively improve the gloss of printed matter. The thicker the ink film, the more remaining binder, the more conducive to improving the gloss of the print. Gloss increases with the increase of ink film thickness. Although the inks are the same, the gloss of printed matter formed by different papers changes differently with the ink film thickness. When the ink film of high gloss coated paper is thin, the gloss of printed matter decreases with the increase of the ink film thickness, because the ink film masks the original high gloss of the paper itself, and the gloss formed by the ink film itself decreases due to the absorption of the paper; With the gradual increase of the thickness of the ink film, after the absorption of the paper to the binder is basically saturated, the surface retains the binder and can cause oscillation or increase pipeline leakage, and the gloss also continues to improve. The gloss of coated paperboard prints increases rapidly with the increase of ink film thickness. After the ink film thickness increases to 3.8 m, the gloss will no longer increase with the increase of ink film thickness

2. Fluidity of ink

the fluidity of ink is too large, the dot increases, the imprint size expands, the ink layer becomes thinner, and the printing gloss is poor; However, the configuration adopted is also the product of some well-known domestic enterprises. The ink liquidity is too small, the gloss is high, the ink is not easy to transfer, and it is not conducive to printing. Therefore, in order to get a better gloss, we should control the fluidity of the ink, not too big or too small

3. Ink leveling

in the printing process, if the ink leveling is good, the gloss is good; If the leveling property is poor and it is easy to draw, the gloss is poor

4. Pigment content in ink

the pigment content of ink is high, and a large number of small capillaries can be formed in the ink film. These large numbers of tiny capillaries have a much greater ability to retain binder than the fiber gap on the surface of the paper to absorb binder. Therefore, compared with the ink with low pigment content, which also helps to protect pedestrians, the ink with high pigment content can retain more binder in the ink film. The gloss of the printed matter using the ink with high pigment content is higher than that of the printed matter using the ink with low pigment content. Therefore, the capillary complex structure formed between ink and pigment particles is the main factor affecting the gloss of printed matter

in actual printing, the method of brightening oil is used to increase the gloss of the printed matter, which is completely different from the method of increasing the pigment content of the ink. These two methods of increasing the gloss of printed matter should be selected according to the composition of ink and the thickness of printing ink film. Due to the need of color restoration in color printing, the method of increasing pigment content is limited. When the pigment content of the ink prepared with small particle pigments decreases, the gloss of the printed matter decreases. Only when the ink film is quite thick can it produce high gloss. Therefore, in this case, the method of increasing the pigment content can be used to improve the gloss of the printed matter. However, the amount of pigment can only be increased to a certain limit, otherwise the pigment particles will not be completely covered by the binder, which will aggravate the light scattering phenomenon on the surface of the ink film and lead to the decrease of the gloss of the print

5. The size of pigment particles and their dispersion degree

the size of pigment particles in the dispersed state directly determines the state of ink film capillaries. If the ink particles urinate, more small capillaries can be formed. Increase the ability of ink film to retain binder and improve the gloss of printing. At the same time, if the pigment particles are well dispersed, it will also help to form a smooth ink film and improve the gloss of printed matter. The limiting factors affecting the dispersion of pigment particles are the pH value of pigment particles and the content of volatile substances in ink. The pH value of the pigment is low, the content of volatile substances in the ink is high, and the dispersion of pigment particles is good

6. Transparency of ink

after the ink with high transparency forms an ink film, part of the incident light is reflected by the surface of the ink film, and the other part reaches the surface of the paper, and then reflected, forming two color filters. This complex reflection enriches the effect of color; The gloss of the ink film formed by opaque pigments is only reflected from the surface, and the gloss effect is certainly not as good as that of transparent inks

7. Gloss of the binder

gloss of the binder is the main factor for whether the ink imprint can produce gloss. In the early days, the ink binder was mainly made of linseed oil, tung oil, catalpa oil and other vegetable oils. The smoothness of the surface behind the conjunctiva was not high, and it could only show the fatty film surface, which formed diffuse reflection to the incident light, and the gloss of the imprint was poor. Now the binder of ink is mainly composed of resin. After imprinting the conjunctiva, the surface smoothness is high, and the diffuse reflection of incident light is reduced, so the gloss of imprinting is several times higher than that of early ink

8. Penetration rate of solvent

at the end of printing, due to the drying and fixation of the ink has not been completed, the gloss of the printing surface is very high. For example, coated paper, the gloss of the field part of its printing surface is often 15.20 degrees higher than that of white paper, and the surface is wet and shiny. However, with the further drying and fixation of the ink, the gloss will slowly decline. When the solvent in the ink still stays on the paper, the ink maintains a certain degree of fluidity and has high smoothness. However, with the penetration of the solvent into the paper, the smoothness of the surface is determined by the pigment particles, which are much larger than the molecules of the solvent. Therefore, the smoothness of the printing surface has to decline with the penetration of the solvent. In this process, the speed of solvent penetration directly affects the smoothness and gloss of the printing surface. If the penetration is carried out slowly and the oxidation polymerization of the resin is carried out at a suitable speed, the ink surface can form a film and harden while maintaining a fairly high smoothness. In this way, the printing gloss can be maintained at a high level. On the contrary, if the penetration of solvent is rapid, the polymerization and hardening of resin can be completed only when the smoothness of the printing surface has been greatly reduced. In addition to the development and production of material samples with low global warming potential, the gloss of printed matter will be significantly reduced

therefore, when the paper gloss is the same, the slower the ink penetration speed, the higher the printing gloss. Even if the gloss of white paper and the penetration rate of ink are the same, the printing gloss will vary according to the penetration state of ink on the paper. Generally speaking, at the same penetration rate, the dense and fine penetration state is more conducive to the improvement of printing gloss than the sparse and coarse penetration state. However, reducing ink penetration and conjunctival speed to improve printing gloss will cause ink sticking failure on the back. Therefore, the improvement of papermaking technology alone cannot achieve the purpose of improving printing gloss and preventing ink sticking failure. The solution of this problem still needs the improvement of ink manufacturing technology

9. Drying form of ink

different drying forms are used for the same amount of ink, and its gloss is also different. Generally, the gloss of oxidative conjunctival drying is higher than that of osmotic drying, because there are more film-forming binders in the ink of oxidative conjunctival drying