Some control points of the most popular fluorescen

2022-08-03
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Some control points of fluorescent ink printing technology with the development of society, fluorescent ink has been more and more widely used. In particular, the printing process of bills, securities, scratch cards, trademarks, book covers, tobacco and alcohol and other packaging products is printed with anti-counterfeiting fluorescent ink, which can not only improve the level of printing process, but also achieve a certain anti-counterfeiting effect. Therefore, correctly understanding and understanding the characteristics of fluorescent ink and mastering the correct application methods of fluorescent ink can not only effectively prevent the occurrence of printing faults in one way or another and improve the printing production efficiency, but also better improve the printing quality of products and meet the printing quality requirements of customers for anti-counterfeiting products

correct understanding of the characteristics and uses of fluorescent inks

the so-called fluorescent inks are inks made of fluorescent pigments. The layout printed with fluorescent ink has the characteristics of converting ultraviolet short wave into longer visible light, and then reflecting charming colors. Therefore, it has a certain anti-counterfeiting effect. The colorant in fluorescent ink, i.e. pigment or dye, is different from ordinary colorants. It can not only reflect visible light, but also absorb short wave light such as purple, blue and green light, and reflect it as visible fluorescence, so that the colored substance will show fluorescence after being excited by sunlight or ultraviolet light. Therefore, the colored substance can produce very pleasant colors with fluorescent effect. Whether a colorant can produce a good fluorescent effect mainly depends on the existence of some atomic groups in its molecular structure. After printing, the luminous fluorescent ink will reflect the visible light of long wave band when irradiating the printed text with ultraviolet light, so it can also present a bright and dazzling color effect in the dark. This is the result of the action of sulfides such as zinc, cadmium and strontium, and it is also the basic characteristic of luminous fluorescent ink. Colorless fluorescent ink can be mixed with other colored fluorescent inks with the same 4-color ink. However, its luminous color and brightness will vary depending on the color and weight of the ink. If it is not properly mixed, it is easy to affect the ink performance. Due to the large difference between the transmitted light wavelength of red and yellow ink and the wavelength of UV fluorescent line, the fluorescent color produced is obvious. When green fluorescent ink is printed on a light background color or white background color, only when the ink layer reaches a certain thickness can it obtain a better fluorescent effect. Based on the good application effect of fluorescent ink in color printing, it is widely used in securities, stamps, trademarks, labels, scraping cards, invoices, navigation marks and other packaging and decoration printing, and has a very broad application prospect

several types and varieties of fluorescent inks

fluorescent inks are divided into screen printing fluorescent inks, gravure printing fluorescent inks, offset printing fluorescent inks, embossing fluorescent inks and flexo printing fluorescent inks according to the type of printing process. According to ink performance, fluorescent ink is used for printing general products, while fluorescent anti-counterfeiting ink is specially used for anti-counterfeiting printing of special products. When using, it is necessary to design according to the characteristics of the printing process and select the corresponding fluorescent ink to ensure that the printing process effect is not affected. Fluorescent ink is divided into invisible anti-counterfeiting ink and visible anti-counterfeiting ink. The pictures and texts printed with invisible fluorescent anti-counterfeiting ink can hardly see the printing color when facing the printed matter. When looking at the printing page obliquely, you can only see the faint and slightly shiny impression. This fluorescent ink is often used to print scraping cards, book covers, invoices and other products. When the ultraviolet light is used to irradiate the printed pictures and texts, the bright, clear and colorful fluorescent pictures and texts will be clearly seen. Because the invisible fluorescent ink is transparent and colorless, it is difficult to clearly observe with the naked eye during printing, which makes it difficult to install and calibrate the plate. According to the practical experience of previous embossing process, it is better not to wash the car and change the color immediately when installing the printing plate with invisible fluorescent ink, but to wash the car and change the color after the completion of plate installation and calibration, which is conducive to improving the efficiency of plate installation and calibration. However, the process of printing with visible fluorescent ink is relatively simple, and the ink color control in the process of plate loading, plate calibration and printing is relatively intuitive and clear. Therefore, the page registration is easy, and the ink color in the printing process is easy to maintain uniformity. Choosing appropriate fluorescent ink to print different products plays a crucial role in the anti-counterfeiting effect of products. If the ink type is not suitable, it is easy to cause poor printing anti-counterfeiting effect, or even fail to achieve anti-counterfeiting effect. For example, the colorless fluorescent blue ink is overprinted on the golden yellow background color. Because the fluorescent blue ink can show blue light under the irradiation of ultraviolet light, and then mixed with the golden yellow light, the yellow light and blue light complement each other, showing white light. This is the result that the golden yellow light of the medium long wave in the spectrum absorbs part of the blue short wavelength light. Therefore, the color of fluorescent blue can hardly be seen, so its anti-counterfeiting printing can not achieve good results. Fluorescent inks of different colors can be obtained with different formulas. For example, UV fluorescent inks with UV excited visible fluorescent compounds can display red, yellow, green, blue and other visible light under UV irradiation. If infrared fluorescent ink with visible fluorescent compound excited by infrared ray is added to the ink, green visible light can be displayed under infrared irradiation. Under the irradiation of fluorescent lamps with different wavelengths, the double wave invisible fluorescent ink shows different fluorescent color reactions. The long wave shows one fluorescent color, while the short wave shows another color. Now some products in order to improve the anti-counterfeiting effect of ink, also use fluorescent encryption anti-counterfeiting ink. This kind of ink is different from the general fluorescent ink. It uses specific encryption components in the ink, which has a personalized anti-counterfeiting effect. When you want to identify the authenticity of the product, you can identify the authenticity of the printing with the help of a special detection instrument. Therefore, the anti-counterfeiting process has a higher effect

some control points of fluorescent ink printing process technology

fluorescent ink is obviously more expensive than ordinary ink. Therefore, whether from the perspective of anti-counterfeiting process or from the perspective of ordinary printing process cost, the layout of fluorescent ink printing should not be too large, especially the field layout is not suitable for fluorescent ink printing. Therefore, fluorescent ink is more suitable for printing small areas of text, signs or patterns. For products printed with fluorescent ink, the printing effect should be fully considered in the layout design. For example, the fluorescent effect is not good when the visible fluorescent ink is directly printed on white paper, but the process effect is relatively good when the layout of overprinting fluorescent ink is designed on a light background color. From the perspective of product anti-counterfeiting, printing small words, letters, etc. with invisible fluorescent ink, and deliberately deforming the local strokes of some words and letters typed from the font, can form a hidden and personalized anti-counterfeiting secret record, and improve the anti-counterfeiting effect of the printed page

the printing paper shall be selected according to the characteristics of fluorescent ink. Because different papers have different effects on invisible fluorescent ink. Light color or color grain paper, the paper color is easy to reduce the brightness of the ink and affect the color rendering effect. In addition, the whiter the paper, the higher the degree of treatment of the paper by the fluorescent brightener. In this way, the fluorescent brightener will emit blue and white light under ultraviolet light, which will interfere with the color development of the fluorescent ink to a certain extent, resulting in the obvious weakening of the fluorescent effect and affecting the technical effect of the fluorescent ink. Therefore, invisible fluorescent blue ink is not suitable for printing paper containing strong fluorescent brighteners. The yellow and magenta fluorescent inks have the strongest visual impact. Paper and paperboard with high gloss, such as coated paper and glass card, can be selected. The fluorescent effect is ideal

pay attention to the reasonable control of printing process. From the appearance of the fluorescent ink, the original fluorescent ink looks dark, but it is very light after printing on the substrate. This must be paid special attention to in ink mixing to avoid waste caused by blind ink mixing. Due to the hard texture of fluorescent pigment, it is not easy to roll fine, so it has poor extensibility in the printing process. Therefore, when printing the layout with fluorescent ink, it is best to first print a layer of vitamin oil on the background color, and then overprint, so that the printing effect is better. When printing acidic paper, a small amount of dry oil can be added to the ink as appropriate to improve the printing process effect, ensure that the product is dried timely after printing, and avoid dirt on the printed product. In order to improve the printing performance of fluorescent ink, it is sometimes necessary to appropriately increase the ink viscosity. For example, under the conditions of high-speed and high-temperature printing, No. 19 resin oil and varnish can be generally used. However, if you print paper and paperboard that are easy to lose hair, or print in a low temperature environment, you should appropriately reduce the viscosity of the ink. If you use fluorescent ink to print transparent film materials, you can first print white ink for backing, and then print fluorescent ink, which can better improve the printing effect of fluorescent ink

clean the inking system to prevent color mixing and color deviation. According to the previous printing process experience, when printing fluorescent oil, but the development speed of the Indian market in the next 10 years will be amazing, the ink transmission device of the machine, including the rubber roller, ink bucket and printing plate, should be cleaned, and then the ink of the desired printing color should be coated on the ink bucket and rubber roller for operation, and then cleaned again, so as to make the inking system of the machine cleaner, When printing, the residual color on the original machine will not be mixed with the color of fluorescent ink to produce cross color development, resulting in color deviation due to impure color of fluorescent ink. If possible, a set of unused ink rollers can be used for printing fluorescent ink, which is conducive to improving the quality of printing color. In particular, it is difficult to clean even slight scratches on the surface of the embossed cots. It is more scientific and reasonable to reserve a set of cots for the operation of printing color products

pay attention to the control of ink blending technology. Using a small amount of color ink mixed with fluorescent ink can improve the color and concentration of fluorescent ink. For example, fluorescent orange red can be adjusted to an appropriate amount of fluorescent orange red and golden red; Fluorescent Princess red can be adjusted with an appropriate amount of peach red, etc. It is worth mentioning that fluorescent inks should not be mixed with other common inks, otherwise, it is easy to reduce the fluorescent effect of inks. The screen printing fluorescent ink can be mixed with phosphorescent ink, and its color effect is better. If the bottom tone of the printing fluorescent ink is darker, the fluorescent effect will be worse. This should be paid attention to when mixing the ink

pay attention to control the printing pressure. As the inorganic fluorescent substance of fluorescent ink is crystal luminous, if the printing pressure is too high, the crystal will be easily broken and the luminous brightness will be reduced. Therefore, the relief printing process is adopted, and the metal plate is not suitable for printing. Instead, the resin plate with soft, good gloss and light printing pressure can keep the ink saturated, and attention should be paid to printing with as little pressure as possible. In fact, it is more appropriate to use silk, gravure and other processes to print fluorescent ink. The printing ink layer is thick, and the fluorescent effect of the printed page is better

pay attention to controlling the printing speed. For fluorescent inks with high fluidity, their drying performance is relatively slow. When printing a large area of layout, the coated ink layer is relatively thick,

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