Flat convex color printing ink preparation and reaction

In Plano-Convex color printing, dispensing ink is one of the indispensable processes in color printing. It is highly technical and requires strict operation. Therefore, the correct and skillful deployment of printing inks is the key to plano-convex color printing. According to the following experience of ink transfer work, talk about the deployment of flat-convex color ink.

First, the deployment of ink to consider several factors

The ink must be formulated according to the paper, quality requirements and hue of the production process, and the ink of the appropriate type and grade should be selected. Such as the use of coated paper printing fine products, then choose bright ink, general product with resin ink, with offset paper printing generally better product selection resin ink. Paper rough paper offset paper, use more ink hiding power. Letters of relief are printed in general, tables are available in books, inks for parts, etc.
After choosing the ink, the ink deployment should first consider:

1, the law of the color change: color samples of various kinds of prints, we must first analyze the color samples of various color ink content. The color science tells us that the basic color of the color is the three primary colors of ink, and the different proportions of the three primary colors are mixed and mixed, and a variety of colors of different hue can be deployed. We should correctly analyze according to the law of color change, whether it is primary color, intermediate color, or complex color. What kind of primary color is the primary color? What are the two primary colors? What kind of primary colors are different proportions of complex colors? What is the proportion of the respective primary colors? This requires careful analysis of the content of its ingredients and basic colors. When analyzing the content of proofs and basic colors, attention should be paid to the lighting, the whiteness of the printing paper, the smoothness, and the influence of the hue difference of the ink itself on the color. For example, the light of a fluorescent lamp will spread the color, the whiteness is low, and the rough paper However, the hue becomes deeper and darker, and the same type of ink produced by the same manufacturer may also have a color difference. Therefore, it is best to watch the color samples indirectly bright daylight. To faithfully reflect the effect of color and color, it is necessary to use paper with high whiteness and smoothness.

2. Physicochemical factors such as ink's pigment, dryness, fluidity, yield value, hiding power, etc.: The ink's pigments mainly control various types of inks. Discoloration, discoloration, weather resistance and chemical resistance. For example, white pigment inks with zinc white pigments are not lightfast, acid resistant and yellowish. The choice of pigment is titanium white ink is far better than zinc white and zinc white; golden red is not sun-resistant, when the ink is best replaced with red and orange, dark blue, poor alkaline resistance, easy to change blue and black; Peacock The blue case of acid turns green, and the alkali turns blue and so on. In order to mix inks, it is necessary to understand the chemical properties of the packaging materials used in the packaging and to grasp the changes in the physical and chemical properties of the ink. Different types of inks have different functions for drying, fluidity, yield, and hiding power. Such as the use of white ink against a small amount of light yellow deployment of light yellow, due to the high content of some white pigments, hiding power, fluidity is also poor. Little attention, very easy to cause ink pulverization, and even things happen at the same time powdering and crystallization. In the preparation of such light-colored inks, it is best to use a diluting agent such as dilute ink and some resin oils suitable for printing performance instead. Some of the light-colored inks must be formulated with white ink, and they can only be formulated with a small amount of white ink. The amount of white ink is adjusted to the positive hue. This will not only avoid some of the shortcomings of the ink in the printing, but also help the gloss and reduce the cost. Therefore, the deployment of ink must understand and grasp the various types, number, different color ink performance.

3, the paper's ink absorption, whiteness, smoothness and other factors: different prints, there are different requirements for the paper, printing fine products require a smooth paper, whiteness, and small ink absorption. Mixing inks To understand paper properties, consider the effect of the color of the product at the time of printing. Offset paper has low smoothness, loose paper, and large amount of ink sucked. When the ink is transferred, it requires less viscous and is moderately thick to moderately increase the amount of ink used. Coated paper has high smoothness, high surface structure strength and low ink absorption. The consistency of ink preparation can be larger. It is better to use bright light to fasten the ink, otherwise the product will lose light and the ink will be dark.

The paper's PH value and dry humidity have a certain influence on the printing ink. Acidity, high humidity, not only affect the ink drying, but also make some ink discoloration pan-color. Alkalinity can also discolor some inks.

4, the type of printing press and imprint speed factors: the press has a round pressure round, round flat, flat and flat, when the deployment of ink, according to different imprinted printing presses, different speed, corresponding adjustment The ink has fluidity, dry stickiness, consistency, and color. Round press (offset) and round presser (horizontal fly, vertical fly), printing speed, pressurize with line contact, short embossing time, thin layer of ink and flat service, ink mix can be a little thicker sticky , Color is slightly deeper than the original, dryness should be appropriate, flat pressure (flat press, square box machine, square disc machine) printing speed is slow, large area and pressure printing, pressure is small, the printing ink layer is thick, ink The deployment should be properly dilute, the color corresponding to slightly lighter, and the round pressure leveling between the two.

5, the printing plate factors: field, reticulate, text, line version, different layouts should be different from the deployment of ink. The authentic version requires vivid colors, uniform uniforms, and good gloss. In the case of ink transfer, minimize the use of auxiliary materials and print normally. It is advisable not to pull the paper without drawing paper. The texture text and line version require the ink not to be too thin, otherwise it will make the dot enlarge too much, the text lines become bloated, the paste version and other phenomena affect the image's level and three-dimensionality, and the overlap printing, but also stamping the electro-aluminum, can be Inks are added with polar auxiliary additives.

6, the number of products and climate factors: the number of products, the temperature is abnormal, but also stacked color, transfer ink, should be flexible to master the printing cycle, grasp the ink in different environments, under different conditions of drying speed, prevent ink crystallization and Powdering occurs.

Second, ink deployment should grasp a good few aspects

Ink is mainly composed of pigments, binders and fillers. Pigments mainly play a role of coloration in the ink; the binder is mainly used as a pigment carrier in the ink and is used to adjust the ink rheology. In the printing process, an auxiliary material needs to be added for printing adaptability. But adding random materials indiscriminately is counterproductive. Therefore, we must fully understand the performance of auxiliary materials and distinguish between resin inks and vegetable inks and their ingredients. The result is not ideal, it does not help print quality. In order to deploy a good ink, the correct use of auxiliary materials, the following briefly describes the deployment of ink should grasp a good few aspects:

1, ink mix and mix, ink mix should try to master the same type of mix principle, such as the deployment of color or complex color without resin ink, had to use vegetable oil ink instead, but should pay attention to the proportion of mixing, if the oil type ink Excessive, has an impact on the quality of the resin, can not reach the purpose of improving the effect of the printing. The ink color just tells us that the more types of ink mix, the darker the color. Therefore, you can use primary colors, never color. Can not use the color of the complex color. When mixing light-colored inks, if the hiding power requirements are not very high, it is best to use diluting agents. Due to the dilute ink contains a large number of synthetic resin and dry oil, fixed fast drying, good light brightness. It works well for printing light-colored ground editions. In addition, bright lacquer can also be substituted. This is very good for gloss and drying of printed products, but care should be taken to prevent and avoid overprinting and overprinting. Wiley oil luster is poor, dry slowly, not high-grade fine product printing, some products can be used to dilute the ink and Weili oil mix and match method. Overprinting problems can be overcome, but the gloss is detrimental.
2, ink dryness adjustment, ink dryness should be based on the ink itself, drying, paper performance, print layout size, number of printing and superimposition of the situation, the workshop temperature and humidity, printing equipment performance and other factors flexible grasp. Generally, the amount of white dry oil is controlled at 10%, red dry oil is controlled within 5%, and too much dry oil will not only change the ink properties, but also cause dirty prints, dry glue, and yellowing of the layout. Therefore, the amount of dry oil should be appropriate.

Generally can follow the following rules:
1 printed color cable products, can be slightly dry, should be controlled within 2%.
2 print version, dry oil consumption is generally 2-8% (25 °C).
3 multi-color overprinting, dry oil consumption should be moderate, a few colors gradually increase the dry oil after printing.
4 with the amount of ink, dry oil should be proportionally reduced.
5 Drying of the ink itself The conjunctiva time should be increased by more than 36 hours, and dryness should be 8 to 12 hours.
6 The paper has high humidity, is relatively smooth, and has an acidic, dry oil acclimation.
7 Low temperature, high humidity, and a corresponding increase in dry oil.
8 The dry oil of the high-speed machine ink has a larger proportion of reference than that of the general low-speed machine, and is usually 1 to 3% larger.

3, ink thin and viscosity adjustment. The ink's fluidity and viscosity are based on the principle of ensuring good ink transfer and transmission. Do not adjust it too thin so as not to affect the color machine network. The viscosity of the ink should be suitable. Normal printing is not suitable for drawing paper.
When the ink flow is small and the viscosity is large, resin varnish or No. 6 varnish can be added. No. 6 varnish should not be too much, and 5% or less is appropriate. Excessive glossiness will be affected.
When the ink flow is large and the viscosity is large, according to the actual condition of the prints, the use of anti-adhesives, detackifiers, polyethylene wax paste, six grain flour, light magnesium carbonate, anti-stick water, high boiling point kerosene, etc. Material reference adjustment. According to the quality requirements of the print, it can be used alone, or it can be used in combination with two kinds. The dosage should be controlled within 2%.

Third, the deployment of common ink

Common inks are divided into dark and light colors. With a primary color and several primary colors (metachrome and complex color) ink, without any bleaching agent collectively referred to as the dark ink of the deployment; where the addition of diluting agent formulated ink is collectively referred to as the deployment of light-colored ink.

According to the theory of subtractive color, when deploying dark inks, the number of primary inks should be minimized. Otherwise, the brightness of the ink should be reduced to affect the vivid colors. However, some products have special requirements for ink. For example, dark browns are usually formulated with red ink and yellow ink plus a small amount of black ink. Different primary colors such as brown, bronze, red purple, false gold, olive green and other shades of color, must use complementary color theory to correct the hue, such as the hue green too heavy, can add a small amount of red ink to overcome; red Taste is too heavy, can add a small amount of blue ink to overcome; purple too heavy, can add a small amount of yellow ink to overcome; black ink requires a darker concentration, can add a small amount of deep red, light blue to improve.

The deployment of dark ink should be based on the color analysis of the printed product and hue, determine the main color and auxiliary color ink. The main color ink is weighed into the ink plate first, then the auxiliary color ink is added, and the difference between the color sample and the original sample is viewed in a comparative manner. The color is added to the original color as the standard, and the color is uniform and the ratio is recorded. Ingredients and quantity.



Source: China Ink Technology Network