I. Introduction
In the printing process, inks play a vital role, and their performance directly affects the quality and visual effect of the printed matter. The main function of ink is not only to transfer images and text to paper, but also to accurately reproduce the colors in the original, ensuring that the print is bright and detailed. High-quality inks are able to maintain consistency across a wide range of printing conditions, thus meeting the requirements of different types of prints.
The three primary colors of ink, cyan, magenta and yellow, are the basis for the color reproduction of printing. These three colors are mixed by subtractive color to produce all the colors found in nature. When these inks are overprinted or side-by-side in different proportions, they can reproduce the rich and diverse colors in the original, making the color representation of the printed matter more accurate and realistic. This color reproduction capability is a crucial part of the printing technology and plays a decisive role in the final printing result.
Second, the color effect of ink
The color rendering effect of inks plays a vital role in the printing process, and different types of inks exhibit different color mechanisms. For transparent ink, the light will pass through the ink film and hit the surface of the paper, and the surface of the paper will reflect the light back to the ink film, through which the ink will absorb the light complementary to its own color, allowing only the same color as the ink film to pass through, and finally enter the human eye The color is the same as the color of the ink film. In the case of opaque ink, when the light hits the ink film, the ink film absorbs its complementary light and reflects the same color as the ink film, so the color that finally enters the human eye is also the natural color light reflected by the ink film.
In color printing, the principle of dot color is also very important. The three primary colors of color and light (red, green, and blue) and the three primary colors of ink (cyan, magenta, and yellow) complement each other, and can present a rich variety of color effects through the superposition or juxtaposition of dots of different colors. Dot stacking is the overlapping of ink layers to produce new colors, while dot juxtaposition is the way of spatial blending, so that the human eye perceives the mixed color. These principles allow prints to express a wide range of colors, thus reproducing the richness of colors found in nature.
In actual production, the color rendering effect of ink is also affected by many factors. The strength of the ink directly determines the color effect after overprinting, and the ink with greater strength will appear more conspicuous after superimposing. In addition, the size of the dots also affects how dark the color is after mixing, with large dots making the color appear darker and small dots making the color whiter and grayish. The whiteness and smoothness of the paper are also key factors, the whiter, smoother, and better reflective properties of the paper, the brighter the color of the ink, and conversely, the lower the quality of the paper, the darker the color. Therefore, in the printing process, the rational selection and adjustment of these factors is crucial to the final color rendering of the ink.
Third, the printing effect of ink
In the printing process, the printing effect of the ink is the key factor that determines the quality of the printed matter. The preparation of the ink before printing, the performance during printing and the presentation effect after printing all directly affect the final printing result. The following is a detailed analysis of the printing effect of ink, from ink preparation before printing, ink expression during printing, and post-printing effect.
Ink preparation before printing
1. The principle of color matching of ink
Before printing, the color matching of the ink is an important step to ensure accurate color reproduction. Yellow, magenta, and blue primary colors are the basis of ink color matching, and a variety of colors can be blended by mixing these three colors in different proportions. For example, mixing yellow ink with magenta ink produces red, and mixing yellow ink with green ink produces green. However, in practice, due to the unsatisfactory transparency, color intensity and light absorption capacity of the ink, color casts often occur, which requires careful adjustment of the blending of color inks to obtain the ideal color.
2. The influence of hue and relative density
Hue refers to the basic color properties of inks, while relative density is the comprehensive expression of pigments, fillers and binders in inks. When inks of different hues are color-matched, their relative density will affect the mixing effect of colors. Relatively dense inks are usually used in larger amounts, while less dense inks are used. If these inks are not properly mixed, they can lead to color deviations that can affect print quality. Therefore, understanding and mastering the hue and relative density of inks is essential to blend color-accurate inks.
3. Adjustment of ink and use of auxiliaries
Before printing, the ink often needs to be adjusted appropriately to accommodate the needs of different printing processes. These adjustments include adjustments to consistency, viscosity and dryness, which are usually achieved by adding adjuvants. Auxiliaries can be divided into several types: adjusting consistency, adjusting viscosity, adjusting dilution effect, and adjusting drying speed. The proper use of these additives can optimize the printability of the ink and ensure that the ink performs better during the printing process.
Ink performance in printing
1. The influence of fluidity, viscosity, permeability, transfer and dryness of ink
In the printing process, the fluidity, viscosity, permeability, transfer and dryness of the ink are the key factors affecting the printing effect. The fluidity determines the transmission and transfer ability of the ink on the printing machine, and excessive fluidity may cause the ink to slide during the transfer process, affecting the uniformity of printing; Too high a viscosity may make it difficult to peel off the paper, and too low a viscosity may affect the adhesion of the ink. Permeability and transfer determine the distribution and adhesion of ink on the paper, while dryness affects the curing speed and quality of printed matter.
2. The influence of machinery and equipment on the performance of ink
The coordination of the ink with the machinery and equipment during the printing process is also crucial. The design of printing equipment, especially the design of the ink conveying mechanism and dampening solution, directly affects the ink transfer effect. If the design of the ink conveying system is not reasonable, it may lead to uneven ink supply and affect the final printing effect. In addition, the pressure adjustment between the ink rollers of the printing machine is also key, too much or too little pressure will affect the transfer and transfer of ink, which in turn will affect the print quality.
3. Process operation controls the thixotropy, viscosity and fluidity of ink
During the printing process, process operations are critical to the control of ink performance. The thixotropy of the ink refers to the change of its fluidity under the action of external forces, and this characteristic requires the operator to maintain the proper agitation of the ink during the printing process to ensure that its fluidity is stable. The viscosity of the ink needs to be adjusted according to the printing speed and the type of equipment, and the viscosity requirements for monochrome and multi-color machines are different when printing. In addition, proper control of the fluidity of the ink can avoid excessive flow or under-flow of the ink, ensuring the uniformity and color consistency of the printed matter.
Ink performance after printing
1. The final printing effect of the ink on the surface of the paper
After printing, the final expression of the ink is mainly reflected in the surface of the paper. For book printing, the ink needs to show sufficient blackness, and for color printing, the vividness and gloss of the ink are the key to judging the printing quality. Different types of inks behave differently on the surface of the paper, for example, oil-based inks are usually used for book paper with a coarser structure, while resin inks are mostly used for color printing papers with higher smoothness.
2. Differences in the performance of different types of inks
There is a difference in the performance of oil-based inks and resin-based inks in printing. Oil-type inks are mainly fixed on the surface of the paper by penetration drying, which is suitable for rough paper; Resin inks, on the other hand, form a smooth ink film on the surface of the paper by curing, and are suitable for coated paper and high-smoothness papers. Therefore, different types of inks need to be selected according to the printing needs and paper characteristics to ensure better performance of the printing effect.
3. The relationship between the color of the paper surface and the effect of the ink
The color and smoothness of the paper surface also have an important impact on the final expression of the ink. The higher the whiteness of the white paper, the better the reflective performance, and the brighter the color performance of the ink; Colored paper, on the other hand, will have an impact on the color of the ink, changing the visual effect of the printed matter. Therefore, choosing the right paper and ink is essential to achieve the desired printing result.
During the printing process, the performance of inks is influenced by a variety of factors, including pre-press preparation, fluidity, viscosity, permeability and dryness during the printing process, and the final appearance after printing. The adjustment of parameters in each link, such as the color matching of inks, relative density, the coordination of machinery and equipment, and process operation, has a direct impact on the color reproduction and quality of printed materials. Therefore, a comprehensive understanding and optimization of every detail in these processes is key to ensuring the quality of your printed products.
It is particularly important to control the matching between the properties of the ink and the characteristics of the paper. The selection and adjustment of ink and the reasonable combination of whiteness, smoothness, absorption and other characteristics of the paper determine the visual effect and color accuracy of the printed matter. By precisely managing these factors, you can effectively improve the overall quality of your prints, ensuring that the final product is bright in color and clear in detail, and meets the needs of different printing needs.
