1. Paper packaging development trends and technical requirements In recent years, the global paper product packaging industry has developed rapidly, and the production capacity of cartons and cartons has increased significantly. In the world packaging industry output value, paper packaging products exceed 32%, and in Europe, the consumption of paper and cardboard is as high as 41%. Per capita paper and cardboard consumption in 2000: 331.7 kg in the US, 249.9 kg in Japan, 229.4 kg in Taiwan, and 28.4 kg in mainland China. In 2000, China imported 13.03 million tons of paper, paperboard and pulp (about 6 billion US dollars), accounting for about 66.7% of China's paper and paperboard consumption. In recent years, the growth rate of Hong Kong's packaging industry is about twice that of the printing industry. In 2000, the sales of packaging industry in Guangdong reached 50 billion yuan, of which 18 billion yuan was for paper packaging products and 14 billion yuan for packaging and printing. 3. Paper packaging printing technology In the field of paper packaging printing, lithographic offset printing, letterpress flexo printing, gravure printing, and silk screen printing coexist, with their own characteristics. In sheetfed cardboard printing, offset printing method is mostly used, and flat screen printing and sheetfed gravure printing method are also used; in web printing, gravure and flexographic printing methods are mostly used, and offset printing and silk printing There are also screen printing methods that use several combined printing methods simultaneously on one printing production line. The printing color of the carton is generally between 2-8 colors, of which 4-6 colors are the most used. Folding cartons, especially medicine boxes, often use spot colors, so the number of printing color sets is mostly 6-8 colors. The number of color sets of sheet-fed offset printing presses is generally 4 colors, basically not exceeding 5-6 colors, while the use of multi-color web presses (including gravure, flexo and screen printing) has increased rapidly. The number of printing color groups has reached 8-10 colors. 3.1 Offset printing technology (1) Digital printing and CTP technology Digital printing technology prints according to the database information with personalized selection, which provides personalized packaging and printing options for paper bags, cartons and corrugated boxes. It can be based on regional or product differences. By changing the design and processing parameters of paper packaging containers, the special printing process can be used to make the folding carton have variable printing colors and hot stamping effects to adapt to the market. The packaging carton (box) has many specifications and a large number of short-form jobs Demand. The application of FM screening technology can eliminate moire, improve the uniformity of gradation reproduction, improve the resolution and clarity of images, and easily realize Hi-Fi printing (Hi-Fi). Although FM screening has strict requirements on printing conditions, it is very suitable for the waterless printing process. High-definition FM dots can significantly improve the clarity and level of expressiveness of printed matter. The arrangement of FM dots is not limited by the pitch of dots and the angle of arrangement like the amplitude modulation dots. Choosing FM dots in printing and copying can show more detailed changes, improve the clarity, and have anti-counterfeiting functions. The digital thin sleeve printing plate has good stability, can effectively control the expansion of the dot, reduce the photopolymer, and improve the image quality and registration accuracy. Not only can improve the printing quality of paper packaging, so that the quality of flexo printing reaches the quality level of offset printing and gravure printing. It can also reduce printing pressure, reduce plate cleaning times, extend plate life (the time limit can be increased by 10-25%), further shorten the preparation time of the machine, reduce the number of downtimes and downtime IT (10-20%). (3) The closed double-scraper cavity ink delivery system adopts a two-roller, forward scraper, and reverse scraper structure to achieve quantitative ink supply, but the ink is often directly exposed to the atmosphere in a large area, making the solvent The solvent of the ink volatilizes into the surrounding air, causing changes in the characteristics of the ink and environmental pollution problems: if the water-based ink is used, air bubbles will be generated, which affects the printing quality. Hypoallergenic Shampoo And Conditioner,Dandruff Removal Shampoo,Tricovel Shampoo,Fudge Blonde Shampoo Zchoise Cosmetic Factory , https://www.gzzchoise.com
As people's environmental awareness is further enhanced, packaging containers such as cartons, cartons, paper bags, paper cups, and paper tubes are more and more widely used in Europe. They are used in various juices, milk, cooked food, fast food, snacks and other beverages. Food cartons are everywhere. According to relevant information reported by the China Tobacco Department, the proportion of domestic hard-packed cigarettes has reached 56%.
With the continuous improvement of people's living standards and the degree of automation of commodity packaging, not only the demand for cartons / cartons has increased greatly, but also the higher quality requirements for the printing quality and processing accuracy of color folding cartons / multicolor cartons . To avoid rabbits producing waste products on the automatic folding and gluing machine, so that the folding carton can automatically complete the processes of opening, forming, filling, and sealing on the high-speed packaging machine. Not only the reasonable design of the carton structure but also the box must have sufficient mold Cutting accuracy and folding paste box accuracy. Multi-color printing, the increase of short-form jobs, improving printing quality and processing accuracy, and reducing processing costs are also market pressures and problems faced by carton packaging and printing companies. Therefore, only by applying modern processing methods and new technologies, in the process of paper packaging printing and post-press processing, can we continuously improve the degree of automation of equipment, reduce the adjustment time of equipment and the auxiliary preparation time of live parts, and constantly adapt to new changes in the market to meet different needs. The requirements of users can improve the competitiveness of packaging and printing enterprises.
2. Paper packaging container CAD technology The more popular carton structure CAD software on the international market, in addition to the basic functions of commonly used interactive graphics software (high-quality, fast completion of graphics generation, editing, modification, dimensioning, etc.) , It should also meet the special requirements of the carton design, easily call the box graphics library and select a satisfactory box structure, enter the box body size (length, width, height) and cardboard thickness, the box structure can be displayed or printed immediately Figure, automatic layout, and output box die cutting layout drawing, printing outline drawing and backing (bottom die) processing drawing; when the user designs or calls the required box sheet structural drawing, as long as the paperboard size and row are input Material gap, you can discharge and compare different discharge schemes, display optimized die cutting discharge diagram and related parameters (such as the number of discharges, cardboard utilization, etc.).
In addition to selecting the standard box shape and changing the shape of the carton, you can also arbitrarily design a special box shape, rotate the carton perspective, and display the opening and closing process of the carton; for different cutting edges, indentation lines, and slotted and broken parts, you should choose Corresponding line types, to control the production of carton samples, die-cutting plates, bottom mold (backing) plates and die-cutting tools to improve the processing accuracy of die-cutting plates and backing plates and the precision of carton production.
The high-definition CTP technology developed by Agfa can provide high-quality outlets for modern packaging and printing. The use of unique laser and optical imaging systems, intelligent multi-beam simultaneous imaging methods, IntelliSpot intelligent outlets and other technologies increase the security of the system, simplify the system structure, and increase the degree of automation and overall efficiency of the system.
(2) The printing quality of FM screening technology mainly depends on the number of dots per unit area and the number of continuous changes from small to large. The greater the number of internet access points in the bit area, the higher the clarity of the printed matter, and the more the dot changes, the stronger the expressiveness of the printed matter, and the more delicate it looks.
In order to improve the quality of printing, amplitude modulation screening, frequency modulation (FM) screening and hybrid screening techniques are often used.
The dots of amplitude modulation and screening are arranged regularly, and the size of the printing ink is changed according to the size of the dots, while the dot size of the frequency modulation and screening is fixed and the distance between the dots can be changed. The amount of ink on the paper changes the color. Amplitude modulation screening has three elements: the number of screen lines, the shape of the dots, and the angle of the screen, while FM screening has only one element, the size of the dots. The smaller the dots, the finer the printed matter, the better the visual effect, which is equivalent to the high number of screen lines during amplitude screening, but the smaller the dots for FM screening, the higher the requirements for printing conditions. Hybrid screening is a hybrid screening technology that combines amplitude modulation and frequency modulation screening technology to form on the same image. In the city of uniform tone, especially in the highlight area, conventional screening can produce a smoother appearance than FM screening. But for high-detail parts, FM screening is better. Advanced screening software can analyze the image to determine where to use the appropriate screening geometry, and combine FM screening with conventional screening to achieve the best overall effect.
(4) Printing color management technology The CP2000 integrated offset press central control system developed by Heidelberg uses TFT ultra-thin screen display technology, and is equipped with prepress interface technology, image control technology, printing color management system, online help system and information Management systems, etc., have formed a quality control model under the conditions of integrated printing. Multi-level printing color management system PCM, including consulting, standardization, pre-press and printing optimization, generating and implementing Icc color profile and other content. With the aim of optimizing the color process and improving the production efficiency of the printing plant, the pre-press and printing equipment are effectively coordinated. Not only can you get high-fidelity colors, but you can also save time, reduce waste, and get efficient production.
(5) Anhydrous offset printing technology Anhydrous offset printing is a lithographic offset printing method that uses special silicone rubber coated plates and inks for printing. It does not require isopropyl alcohol or other chemical fountain solutions necessary for traditional lithographic offset printing. . The printing process is simple to operate, without adjusting the water-ink balance relationship, and transfers the ink to the printing plate within a certain temperature range.
The printing plate used for waterless offset printing is a flat intaglio plate, and the graphic part is lower than the surface of the printing plate. Although the plate making process is the same as the PS plate, it is different from the PS plate. Therefore, waterless offset printing plates have unique processing difficulties. Plate, ink and temperature control are the key to waterless offset printing technology, which directly affects the development speed of waterless offset printing. The printing plate is the core of waterless offset printing. The waterless offset printing plate has the advantages of easy operation, good image quality, high printing density, colorful colors, and good printing quality. However, the durability of the printing plate is easy to operate Effects of conditions and special prints. The special ink used in waterless offset printing has the characteristics of low viscosity, high viscosity, large thixotropy and stable performance. Because different colors of ink respond differently to temperature changes, it is necessary to control the temperature of different printing color groups. Although the cost of consumables for waterless offset printing is relatively high, the waste rate of printed products is low and the production efficiency is high. It can be seen that with the progress of technology and the increase of labor productivity costs, especially for high-quality fine paper packaging, waterless offset printing technology has certain advantages and will be further developed and promoted.
3.2 Flexo printing technology New flexible plate and thin plate technology, sleeve printing plate and computer direct plate making technology, environmental protection UV ink, high net line ceramic anilox laser engraving technology, closed doctor blade system, gearless transmission technology The development and application of related technologies such as non-stop roll changing device and automatic control technology have promoted the rapid development of flexo printing. (1) Thin plate and CDI technology The improvement of the quality of photosensitive resin plates and the appearance of thin plate technology have laid a good foundation for improving the quality of the plate, the application of CTP technology and the emergence of digital flexible plate making technology (CDI), It can effectively overcome the phenomenon of network expansion, ensure print quality, shorten production cycle, and reduce cost consumption.
The CDI system jointly developed by DuPont and Dupont Seri can directly transfer digitized information to the laser photosensitive printing plate. The CDI platemaking machine Spark XT developed by Esko-Graphics is mainly aimed at the packaging and printing market, especially small and medium-sized label and folding carton flexo printing enterprises. As technology continues to advance and various systems have successively introduced flexo digital imaging plate-making systems, the cost is also decreasing, and the proportion of paper products such as cartons, paper bags, and multi-layer packaging bags is increasing.
(2) Sleeve type high mesh wire ceramic anilox roller Laser engraving ceramic anilox roller is to spray the alloy on the surface of the treated base roller as the bottom layer, and then spray the ceramic powder with high temperature plasma, after diamond grinding and polishing, use The high-energy laser beam accurately carves out a sharp, steep net hole, and finally performs a fine polishing. The number of mesh lines and the amount of mesh ink are the most important parameters for making laser engraved ceramic mesh. The anilox roller with high screen count can form a thinner and more uniform ink layer, which can meet the requirements of printing with rich layers of layers, especially to meet the needs of its high-gloss part. It can reduce the expansion of dots during printing and maintain a constant and uniform Ink transfer volume.
Sleeve type high mesh wire ceramic urn anilox roller. Using ultra-high-energy laser beam engraving technology and a sleeve-type anilox roller structure composed of a mandrel, an air support roller, and a sleeve, not only ensuring the quality of the high-precision anilox roller, but also realizing rapid replacement of the anilox roller The plate cylinder and the anilox roller adopt a sleeve structure and direct drive technology (that is, the rotation of the anilox roller is directly driven by the plate roller), which solves the problem that the repeated length of the printed product of the flexo printing machine is limited by the gear pitch . Therefore, when replacing printed products with different circumferences, there is no need to replace the mandrels and gears of the plate cylinder and anilox roller, which greatly reduces the time it takes to replace the platen roller and anilox roller when replacing the product.
The carbon dioxide laser engraving ceramic anilox roller has a line number of up to 1,000LPI. The use of a special ceramic layer or super hard ceramic layer can increase the service life of the ceramic anilox roller and reduce the cost of use.
The ceramic anilox roller processed by YAG laser engraving technology has smooth mesh hole wall and neat mesh wall, high finish, accurate ink transfer, and small scraper loss. Not only the ceramic anilox roller has a long service life, but also can extend the Service life. High-power, high-precision YAG laser engraving machine can engrave 16001pi anilox roller.
The closed double-scraper cavity ink delivery system is composed of ceramic anilox roller, two scrapers, sealing strip, ink storage container, ink pump, ink delivery hose and other components. In a fully enclosed system, the scraper, seal, pad, and pressure plate are all mounted on a cavity type bracket, and they are mechanically (or pneumatically or hydraulically) pushed to the ceramic anilox roller, and a certain pressure is applied, and then Connect the ink delivery tube and the return tube to the ink pump and ink storage container respectively to achieve quantitative ink supply. The reverse scraper structure is adopted, which is suitable for high-speed operation, reducing the volatility of the solvent in the solvent ink and the problem of environmental pollution. The system can also be quickly docked with an automatic cleaning system to facilitate rapid cleaning to reduce ink replacement time and downtime.
(4) Environmentally friendly flexo printing inks Today, people are paying more and more attention to environmental protection. Water-based inks and UV inks meet market demand and promote the application of flexographic printing in the field of packaging printing. It can be used not only for printing on various coated paper, offset paper and whiteboard paper, but also for printing on printing carriers such as gold and silver cardboard, synthetic paper, self-adhesive paper and corrugated paper box.
Water-based (or water-based) inks use water as the main solvent, non-toxic, non-polluting, and no residual odor, completely eliminating the harm of certain toxic substances in the solvent ink to the human body and the pollution of packaged goods, effectively reducing atmospheric pollution To improve the environmental quality and printing environment, especially suitable for packaging and printing with strict hygienic conditions such as pharmaceuticals, food, beverages, tea, tobacco and alcohol, and daily necessities in contact with the human body.
Under ultraviolet irradiation, the photoinitiator in the UV ink is excited to decompose into free radicals, and the free radicals cause the cross-linking reaction to occur quickly, causing the colloidal components to become solid instantly. Because UV inks are mainly composed of pigments, photosensitive resins, reactive diluents, photoinitiators and additives, they do not contain volatile organic solvents, which can greatly reduce VOC emissions, and consume less energy, the equipment covers a small area and is easy to dry. high productivity. Since the UV ink does not have the problem of water or solvent volatilization, the transfer and reduction of dots are good, and the colors are more vivid, which greatly promotes the improvement of the quality of flexo printing. Although the drying cost of UV inks is significantly higher than that of water-based inks, UV inks have good photocuring efficiency and ink layer properties, and can well protect the surface of printed products.