Introduction

With the steady development of my country's offset printing market, offset printing inks have also developed rapidly, and their quality levels are basically close to or reaching the international advanced level. According to incomplete statistics, in the past two years, the proportion of offset printing ink in my country's ink market has increased to 50% to 60%, still occupying a dominant position, and this proportion will not increase for a long time in the future. Big changes.

The offset printing market puts forward new requirements for inks

Currently printing, publishing and packaging printed matter are gradually developing in the direction of personalization, diversification and high-end. In order to meet the new changes in the printing market, The printing factory constantly updates and improves printing equipment. The emergence of high-speed, multi-color, low-pollution, and high-efficiency printing equipment has also put forward new requirements for ink manufacturers. In order to adapt to the requirements of high-speed printing, short-run jobs, and comprehensive automation, the offset printing inks produced by ink manufacturers must have the following properties.

(1) High-speed adaptability: It can adapt to printing speeds of more than 14,000 sheets/hour.

(2) Quick-drying performance: Due to the short production cycle, short-run jobs need to enter the four-color printing machine immediately after printing, such as glazing, lamination or die-cutting, so the ink is required to be quickly Drying to facilitate smooth post-processing.

(3) Good water resistance, fast ink balance.

(4) Stability during the printing process: the ink transfer rate and dot increase rate do not change with changes in speed, time, and temperature.

(5) The packaging is convenient for printing plants: vacuum tanks, plunger tanks adapted to automatic ink supply systems, barrels, cans, etc.

(6) Ink is versatile.

Environmental protection requirements

With the development of the economy, the call for environmental protection is getting higher and higher. The printing industry has put forward new requirements for offset printing inks in terms of non-toxicity and pollution-free. Environmental protection Offset printing inks have received widespread attention from users and have begun to be used in packaging, newspapers, commercial printing, etc. Environmentally friendly offset printing inks have been widely used in the United States, Japan and other countries, but their domestic applications are still quite rare. There are technical factors, but the main reason is lack of understanding. Environmentally friendly offset printing inks are mainly aromatic-free soy inks. PAH (polycyclic aromatic hydrocarbons) contained in traditional ink ingredients is a volatile solvent for printing film, which is harmful to the human body; the volatile organic compounds contained in it not only increase air pollution, but also cause harm to the human body. Offset soy ink uses soy environmentally friendly materials to replace some petroleum solvents, which can reduce environmental pollution and harm to the human body. The current situation of the domestic offset printing ink market. With the development of China's printing industry, the pace of development of the domestic ink industry is also accelerating. With the installation and commissioning of a large number of imported and domestic high-speed offset printing machines, the adoption of new printing materials, and the special requirements of new printing processes and post-press processing, ink manufacturers rely on scientific and technological progress to continuously develop new marketable products. Improve old products, product varieties are becoming increasingly rich, and product quality is gradually approaching the international advanced level. The updating of ink production equipment and the improvement of production technology have gradually attracted the attention of various ink manufacturers. In the past 10 years, major domestic ink manufacturers in Tianjin, Shanghai, Hangzhou, Shenzhen, Taiyuan and other places have paid attention to collecting market information for printing materials, and constantly developed new offset ink products that meet market demand, such as bright quick-drying inks, cardboard inks, < /p>

Matte paper ink (matte paper ink), press web ink, cold-set offset web ink, UV ink, offset synthetic paper ink, iron printing ink and heat-set inks newly launched in China in recent years The output of offset web inks and other products is increasing year by year, and the quality is close to the international advanced level of three-dimensional printing, and has been recognized by domestic and foreign printing customers. In addition to replacing high-end offset printing inks that had to be imported in the domestic market, some domestic offset printing ink products have also entered the international market. Some high value-added special offset printing inks have also been successfully developed to meet the requirements of special printing.

Sheet-fed offset printing inks have maintained a steady upward trend in the domestic printing market. With the innovation and improvement of printing machines, domestic sheet-fed offset printing inks have adapted to the needs of high speed, multi-color, quick drying, high efficiency and energy saving. To meet the needs, Tiantian Printing has continuously developed new products and expanded its applications in the field of packaging and printing, such as tobacco, alcohol, food, cosmetics and other industries, meeting the requirements of "high gloss and high density" for book printing and "quick drying and friction resistance" for packaging printing. Performance requirements in other aspects; web offset printing ink also adapts to the rapidly growing needs of the newspaper industry and commercial printing. Printing Co., Ltd. continues to improve quality levels and output.

my country's offset printing ink products are mainly offset printing bright quick-drying inks, non-heat-setting offset printing inks, etc. The leading products are printed in Shenzhen, followed by heat-setting offset printing inks, UV offset printing inks, and synthetic paper offset printing inks. , offset printing iron ink, waterless offset printing ink, offset printing metal ink and various special inks for offset printing. Moreover, domestic heat-setting offset printing inks and UV offset printing inks have developed rapidly in the past two years. The gap between domestic offset printing inks. Compared with similar foreign ink products, domestic offset printing inks still have many shortcomings in rice paper printing and cannot fully meet the needs of today's packaging and publishing printing markets.

(1) Offset ink manufacturing process. The ink production process has a low degree of automation, the ink detection method has a low degree of automation, human factors affect many printing industry presses, and the stability of raw materials is poor, resulting in a gap in quality consistency and stability of ink products.

(2) Standardize the color of offset printing ink. Internationally, offset printing ink color standards include European standards, Japanese standards, American Pantone standards and other South China printing standards, but my country's offset printing inks do not have their own color standards.

(3) Wide color gamut ink. Using four-color inks with a wide color gamut to replace six-color or seven-color inks for printing can not only improve the quality of printed matter but also improve production efficiency. However, the field of domestic wide-color gamut offset printing inks needs to be developed.

(4) Four-color ink suitable for high-speed overprinting. Domestic four-color overprinting inks still need to be further improved in terms of high concentration, high transparency, brightness and excellent overprintability.

(5) Environmentally friendly offset printing ink. Printing manufacturers, my country's printing industry is facing great environmental pressure. Since most of the inks used in printing contain organic solvents (compared with solvent-based inks, offset printing inks contain very little organic solvents), letterpress printing, the volatilization of organic solvents and Emissions can cause environmental pollution. In addition, ink contains harmful heavy metal elements such as lead, chromium, cadmium, mercury, arsenic, and barium, which are extremely harmful to the human body and the environment. From the perspective of environmental protection and health, more and more users of Huacai Printing regard low toxicity, environmental protection and pollution-free as important conditions when purchasing inks. In my country, the research and development of environmentally friendly offset printing inks is still restricted by many factors, but for the Chinese ink industry, the ultimate realization and promotion of green inks is the development goal and ultimate pursuit of small printing presses.

(6) Waterless offset ink. Waterless offset printing does not use fountain solution, which can be said to have made a great contribution to environmental protection. It is expected that waterless offset printing will have good room for development in light paper printing in the past two years. However, waterless offset printing ink is greatly affected by the ambient temperature during the actual printing process. It is easy to get dirty and requires special waterless offset printing equipment. In addition, because waterless offset printing plates are relatively expensive for notebook printing, its domestic application and promotion are subject to certain restrictions, and its development is slow.

Directions for future efforts

(1) Shorten the distance. As the output of offset printing ink gradually increases, the production process of offset printing ink is gradually developing towards automation. By introducing advanced equipment, the control level of my country's ink production process is improved; by increasing the single batch output of ink, the consistency and quality of ink are improved. stability.

(2) Establish China’s own offset printing ink color standards. The National Printing Standardization Technical Committee has made preliminary plans for the development ideas and work routes of the "China Offset Ink Color Standard" and the related "China Printing Paper Color Standard" and "China Printing Color Standard". The drafting of relevant standards will start from now on. Sample collection and experimental verification work. In printing production, my country's standardization work is in full swing.

In short, offset printing ink, as one of the raw materials for offset printing, must maintain its own advantages, while absorbing and learning from advanced foreign experience. By introducing advanced technology and equipment, it will improve the technical level of my country's offset printing ink production and equipment. Printing Industry Press , improve the quality of offset printing inks, establish color standardization of ink products, and strive for the rapid development of my country's ink industry.

There are many types of inks with different physical properties. Some are very thick and sticky, and some are quite thin. Its components can be divided into three parts: the liquid component is called the binder: the solid component is the color material (pigment or dye) and various auxiliaries. Different inks dry in different ways; different printing processes use different inks; different substrate materials use different inks. Inks are classified below according to the drying method of the ink, different printing processes and substrate materials.

Printing ink is a paste-like colloid that is uniformly mixed with pigments, binders, fillers and other materials. The color material gives the printed matter rich and colorful tones; the binder serves as the carrier of the color material and also serves as an adhesive to fix the color material on the surface of the substrate; the filler gives the ink appropriate properties, making the ink meet the printing suitability of various printing processes. sex.

The ink should have a certain fluidity, meet the properties required by various printing processes, and be able to dry quickly on the printed matter. The dried ink film should have corresponding various water resistance, acid resistance, and water resistance. Resistance to alkali, light resistance, abrasion resistance, abrasion resistance, etc.

The liquid component in the ink component is called the binder; the solid component is the color material (pigment or dye) and various additives.

For ink, color, body (usually the rheological properties of ink such as consistency and fluidity are called the body of ink) and drying performance are the three most important properties of ink, and they are also Things that should be paid attention to when developing ink formulas and processes and producing inks; the printing film on the printed matter should have a certain degree of resistance so that the printed matter can be of practical use.

The rules of color change

1. The mixing of ink is based on the principle that the three primary colors Y, M, and C of color materials can be mixed in a certain proportion to produce black.

2. Mixing the three primary color inks Y, M, and C in equal proportions can produce black. Adding different proportions of diluents can produce varying degrees of neutral gray.

3. The three primary color inks Y, M, and C can be mixed in different proportions to obtain secondary colors or complex colors of different hues. The secondary colors of the three primary color inks Y, M, and C are R, G, B, Y, M and C are complex colors. One thing to note is that the prepared hue is biased towards the hue of the ink with a larger proportion.

4. Mix the two primary color inks in equal amounts to obtain the standard secondary color.

Color matching method

1. Chromatographic color standard comparison method. For example, for a solid full-page spot color on a color manuscript, the proportion of the amount of ink that matches that color can be determined from the chromatogram and color scale. From the color spectrum, you can find the percentage of dots in each version of Y, M, and C for halftone colors with dots.

2. Comparison method of three attributes of color

Compare the brightness, hue and saturation of the ink color prepared from the color draft sample respectively.

① If there is a difference in brightness, it can be corrected by adding diluent.

② If there is a difference in hue and it is biased toward a certain color, you can use the complementary color rule to correct it, but this will increase the neutral gray and reduce the brightness of black.

Requirements for blending ink

1. The hue of the ink must conform to the color draft of the decoration design, minimize the gap, and strive to have the same color tone.

2. The prepared ink should not be too thin or too thick. The ink should have a certain viscosity and fluidity.

3. A certain amount of red and white drying oil must be added to the entire cigarette and wine packaging and decoration, as well as trademarks. The amount should not exceed 5% of the ink volume. If too much drying oil is added, crystallization will occur. , affecting the matt color of the ink. Adding too little drying oil will cause the back to become sticky. Therefore, the amount of drying oil must be appropriate and must not be too much or too little.

4. Choose ink with good texture. The nature and hue of the original ink from different manufacturers are different. It is best to choose ink products from one manufacturer.

5. When adjusting ink, you must consider the nature of the paper you are printing on. The rougher the paper, the stronger the ink absorption, and the more ink will be consumed during printing. You must control the temperature difference to increase or decrease the amount of drying oil.

6. The prepared ink should be enough for one time use, with a little leftover. Avoid mixing the ink if the amount is too small. The printed hue will be different. If the amount of ink is large, the original ink will be wasted.

7. Conduct detailed analysis of the color draft of the packaging design, and strictly calculate and master the ratio of original ink to added diluent.

8. After the ink is adjusted, the color samples printed on the machine should be carefully compared with the color manuscript. Hue errors should be corrected in time. When washing ink and changing colors, it is required to clean the ink fountain and ink roller. Generally, In some cases, it needs to be cleaned multiple times to avoid the problem of ink color cast caused by dirty ink washing and color changing.

9. Record the ingredients of the blended ink and the quantity of the blended ink in detail so that the stub can be archived and used as a reference for the next repeated printing.