CTP application of the hottest technology in flexo

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CTP application of technology in flexographic printing (Part 1)

as we all know, CTP (computer toplate) technology mainly makes high-quality printing plates with the help of computer technology and laser technology. Compared with the traditional plate making technology, its advantages are shown in many aspects. The quality of the printing plate completed by CTP technology can be said to have a qualitative jump. CTP technology first appeared in the 1980s, but due to many factors, it was not until the 1990s that it gradually matured and gradually reached the level of industrial application. According to statistics, the number of CTP equipment installed worldwide in 1995 was more than 300, in 1996 it was more than 700, and in 1999 it reached more than 6000. By 2000, the number of CTP equipment installed worldwide had soared, and the whole market urgently needed to increase to more than 10000 reliably. In addition, according to the survey, by the beginning of 2002, the number of CTP equipment in Japan alone had exceeded 1000, and it is expected that by this year, the number of CTPs will reach more than 3000. Moreover, with the reduction of technical costs and production costs, as well as the growing maturity and diversification of CTP related supporting equipment and consumables (especially plates), we have reason to believe that the number of CTP installations in the world's printing industry will increase at a higher rate. The above data all illustrate the fact that in today's digital and information age, in our printing field, the trend of CTP technology dominating the world will become an inevitable trend

of course, most of the CTP installations mentioned above are still concentrated in the offset printing area. Then, as a green and environmental protection printing rising by 40 yuan/ton in the emerging Fujian region, what is the application of CTP technology in the field of flexographic printing (especially domestic flexographic printing)? We know that in recent years, flexographic printing technology has made great progress, not only experienced the transformation from toxic "aniline printing" to green printing, but also the quality of flexographic printing is comparable to offset printing and gravure printing. In China, the rise of flexographic CTP technology has been in the past two or three years, while in foreign countries, many powerful large companies have long been committed to the research and development of flexographic direct plate making technology. As early as 1995, CTP equipment using laser technology to carve polymer photosensitive resin plates has appeared abroad. At the drupa exhibition held in the same year, these advanced equipment appeared one after another and soon attracted people's attention. According to the data, flexographic printing has occupied a considerable proportion in foreign countries, especially in developed countries such as Europe and the United States, which is basically equivalent to intaglio printing and offset printing. It is not only the food and drug packaging that are closely related to people's lives, but also the technical use rules of Jinan new era assaying Instrument Co., Ltd. for materials. We have our own unique technical support for the use of flexographic printing, such as magazines Such tensile strength as newspaper is reduced to the lowest; When the consumption of CPE is 60 ~ 80 parts, the market that has been firmly controlled by offset printing for a long time has also begun to use flexographic printing. Among them, CTP technology naturally plays a very important role. At present, the main manufacturers of internationally renowned flexographic direct plate making equipment include Ascot, Cleo, Haier, fexolaser and MDC in Switzerland

compared with the earlier and faster development of flexographic printing in foreign countries, the development of flexographic printing in China is much slower. In fact, many large domestic printing plants have long noticed the development prospect of flexographic printing, and there are not a few companies that spend a lot of money to introduce foreign advanced printing equipment. However, for a long time, neither the source of business nor the quality of printing materials can reach the highest level, mainly focusing on low-grade cartons and packaging and printing with low requirements. Among them, the inability of the domestic plate making industry to provide high-quality plates can be regarded as the main factor. As we all know, flexo belongs to the branch of letterpress printing, and the plate material used is polymer resin material, which has a certain elasticity. From the three-dimensional structure of the printing plate, the "graphic part" of the plate after photopolymerization and post-processing is raised, and the "non graphic part" is recessed. During printing, the raised part transmits ink to form a pattern, and the recessed part is a blank area if it is not inked. Compared with letterpress, the hardness of flexo is relatively low. A lower hardness can increase the inking amount of the field part in the printing process, making the field part appear thick. But on the contrary, the lower hardness will make the dot part expand greatly under a certain printing pressure. At the same time, due to the vacuum pumping and the multiple reflection of ultraviolet light in the process of traditional flexo printing, there is a certain point expansion in the process of plate making. The point expansion of these two (double expansion in the process of plate making and printing) usually makes the point expansion value of traditional flexo printing reach 25% - 30% in the middle tone part, and even 10% - 15% in the high light and dark tone parts. Just imagine how much each tone level of the image will be lost by such a large point enlargement value! It is no wonder that the plate making factory cannot provide high-quality printing plates, which leads to the fact that no matter how good the printing machine is, it cannot print high-quality products. After a long-term vicious cycle, the flexible source of flexo printing can only focus on low-grade products. This is also the main symptom that the market share of domestic traditional flexographic plate making and printing has not improved greatly for a long time

but what has changed since the first domestic flexographic plate making manufacturer first introduced foreign advanced flexographic CTP plate making equipment in 2000? As one of the domestic technicians who first came into contact with flexographic CTP equipment, the author has the honor to personally experience the development pace of the domestic flexographic CTP era. I remember that when the first flexographic CTP equipment was introduced, it was also catching up with the opportunity of a major change in people's awareness and concepts of environmental protection, especially in the sanitary products, food and pharmaceutical industries closely related to people's lives, which began to pay attention to and attach importance to flexographic printing. At that time, the whole printing industry had a high voice for flexographic printing, an environmentally friendly printing method, and the attitude of insiders was also relatively optimistic, But the overall pattern of the printing industry has not changed much. In the first period of time after the CTP equipment was completely installed and debugged, all printing manufacturers took a wait-and-see attitude towards CTP technology. On the one hand, this is a brand-new technology, which needs to be explored and run in by both plate manufacturers and printing manufacturers in terms of hardware and software; On the other hand, at that time, many factors (such as supporting equipment and consumables), especially the limitations of CTP plates, made the production cost of CTP plates much higher than that of traditional plates. Therefore, at the beginning of the introduction of CTP equipment, it mainly stayed in the stage of publicity, experiment, sample and small batch production. After a period of samples and running in, both plate manufacturers and printing manufacturers, as well as other people in the industry, have gradually realized the many advantages and advantages of CTP printing plate. Compared with the traditional version, the obvious advantages are reflected in the following points:

first, CTP can easily deal with many fine moving parts with high requirements (such as rich levels and high number of lines), The number of lines in traditional flexo printing is mainly 150lpi and below, while the highest number of lines in CTP can reach 200lpi. CTP technology can solve the problem that some "hierarchical versions" must have "absolute" (pointing to the gradual change from "yes" to "no") effect. In the previous period of traditional plate making, if you encounter "gradient" products, you can either persuade end customers to change the design style to suit flexographic printing, or you can only choose other printing methods. As mentioned above, the printing plate dots of traditional film drying have a large expansion rate, especially the highlights and dark tones. Not to mention plate making, sometimes it is difficult to ensure the firm existence of these dots even on the output film, let alone let these dots be firmly established on the printing plate with a certain thickness, that is, the printing plate contains these dots, but it is reflected in the printed matter that it has "completely changed". For CTP printing plate, due to the use of digital process and high-resolution rip system, coupled with high-precision laser technology, its ability to reflect the shape and structure of small points is difficult to compare with traditional plate making. Therefore, CTP plate making process can to a large extent grab some medium and high-end products that can only be made by offset printing and intaglio printing

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