Application of the hottest CTP technology in the f

2022-07-26
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The application of CTP technology in the field of flexographic label printing in China

with China's accession to the WTO, the pace of opening to the outside world has been further accelerated, and foreign-funded enterprises continue to pour in. More than half of the world's top 500 enterprises have invested and built factories in China. China has become the world's manufacturing factory on the spot, and the packaging and printing industry as an auxiliary service has also made considerable progress. In recent years, there has been a new trend in the label field. Narrow width UV flexographic printing is increasingly used in label printing

1. Current situation and development trend of label printing in China; In recent years, due to the entry of foreign-funded enterprises and the appreciation of domestic minlei enterprises for this industry, the flexible label printing market has achieved considerable development in recent years. China, as a large hoop production country, is also the country with the greatest label printing potential. In the future, label printing will develop in many aspects. Label printing plants with various business scopes and processing types have their own development space. Especially in the overseas market, the number of UV flexographic printing in the label printing field will increase rapidly, the market share and quality level of domestic equipment will also be greatly improved, and the market share of self-adhesive labels using flexographic printing is growing rapidly. The rapid development of plate making technology, especially the application of CTP laser direct plate making technology, has improved the supporting services in the flexo printing market, greatly improved and stabilized the quality, and made the label printing market more standardized. Flexo printing adhesive label is the future development direction

II. Introduction to label flexo direct plate making technology and its advantages

ctp technology is not a new technology in foreign developed countries. As early as a few years ago, it has been highly popular in the European and American markets. Due to the late start of this industry in China, it is still in the stage of promotion and application of new technologies. The practical application has proved that the computer direct flexographic plate making is a very effective plate making method, which not only improves the process quality, but also brings many advantages to the printing process. For example, the setting of the printing machine is more convenient, the number of plate cleaning is less, and the consistency of the whole printing quality is higher. In addition, with digital flexo, label printing, which could only be completed by offset printing or gravure printing, can now be completed by flexo printing. The main difference between traditional flexo and laser flexo is that during the production of laser flexo, a black laser sensitive layer is added to the surface of the flexo. The main function of the black film is to replace the film in the traditional flexo plate making process. The composition of digital flexo is shown in Figure 1. The traditional production of flexo is to transfer the image data to a Phototypesetter, and then produce the film of flexo. In the case of laser flexo plate making, however, the cost is high. The plates are directly placed on the flexo CTP plate making machine, and the image data are transmitted to the laser one by one. The laser emitted by the laser ablates the black film, making it volatilize, so as to form the desired image on the plate surface, and then the plate is removed from the plate making machine for exposure and development. In addition to sexuality, this is crucial in controlling the printing and the completion of the final printed matter. In addition to the role of the laser sensitive black film in blocking UV light, the UV exposure of the laser flexo plate is the same as that of the traditional flexo plate, and the subsequent development is also the same as that of the traditional plate making. In the process of UV exposure and development, the purpose and function of each step are the same, but there are some subtle differences that we need to pay attention to. Figure 2 shows the outline of laser flexo points and traditional flexo points. The outline of laser flexo points is sharper than traditional flexo points. It is these sharp points that improve the quality and performance of flexo and eliminate the film. The accuracy of imaging technology ensures the consistency of printing plate quality and improves the quality. More importantly, we can control the whole process through data information through data and standardization

laser flexo plate making technology requires an external drum structure and multi beam laser imaging head, which can accurately and repeatedly ablate and volatilize the black film. The THERMOFLEX THERMOFLEX flexo direct plate making machine of Cleo is used here to illustrate that it adopts the multi beam laser head imaging technology and uses the laser diode as the laser light source; These laser heads have different models. According to the needs of users, the maximum laser beam can reach 64. All flexo CTP suppliers now tend to adopt multi laser beam technology. Image quality and repeatability are also directly related to the ability of each laser beam to completely remove the photosensitive black film. The main purpose of laser imaging is to ensure the complete removal of the black film. The equipment providing the Gaussian laser beam (Fig. 3a) has irregular energy distribution, so the accuracy and consistency of imaging are limited. Cleo's thermo God flexo direct plate making machine uses multi beam laser diodes, and the adopted technology can provide continuous energy distribution (Fig. 3b), so the imaging has high accuracy and consistency

in the traditional flexographic printing, the biggest problem is that the point enlargement is too serious, so it is difficult to show points below 5%, and the middle and dark layers are easy to lose. At the same time, due to the ductility of the flexographic plate, overprint is also difficult. In view of the above problems, thermal direct plate making technology makes the quality of flexo printing close to offset printing through various technical means. The most important thing is that the quality of plate making is greatly improved

as the laser flexo plate making technology is that the laser is directly exposed and imaged on the carbon mask layer, there is no need for film, and there is no need to vacuum the Japanese and Western plates. Compared with traditional flexo plate making, it has the following advantages:

1 It can reproduce points from 2% to 98% during printing

large dots have much less dot enlargement than small dots because of their large bearing area. In digital flexo, the dot enlargement of small dots can be effectively controlled because the height of small dots is lower than that of large dots

2. Stably reproduce the intermediate point level

3. because the traditional film process is omitted, the relative cost is lower and the efficiency is higher

4. the details at the high light and dark tone are retained, and the flat and gradual changes are very flexible. The service life of the tensile machine is also consumed quickly

5. UV plate printer and plate printer are also required, and the customer's existing equipment investment will not be wasted

6. in laser flexo printing, the center point always contacts the substrate first, while in traditional flexo printing, the edge of the point contacts the substrate first, so it is easy to cause hollow points. Laser flexo printing does not have this problem

III. application of flexographic direct plate making technology in the field of flexographic labels in China

compared with high-end flexographic label products in developed countries in Europe and the United States, the printing quality in China is much inferior. During the druba exhibition, the author led the domestic industry personnel to visit a well-known flexographic plate making company in Hamburg, Germany. The main business of this company is that high-quality flexographic labels can control any servo motor, variable-frequency motor or DC motor with pulse or voltage control interface to achieve smooth and stepless speed regulation for plate making. It also makes some high-quality flexographic color box packaging plates. This company, which even has only more than 40 business logistics personnel, has an annual CTP flexographic plate making volume of more than 15000 square meters, The total amount and quality of its plate making are inferior to those who visit the industry in China. Why can't domestic flexographic labels print the same quality of offset printing as foreign ones? It is not that the quality of flexo printing machine is not good. The main problem lies in the production of flexo printing plate. In foreign countries, almost all high-quality flexo printing plates are made directly by flexo printing, and the process has been very mature. In China, the technology is still in the promotion stage, and there are still many problems to be solved

at present, the most important problem facing the promotion of flexo direct plate making technology in China is the price. Whether it is plate making equipment, proofing system or digital flexo plate, its price is higher than that of ordinary flexo plate making. However, digital plate making eliminates the processing of film, development and fixing, as well as all kinds of chemicals, places for storing film and vacuum operation procedures for film and printing plate during printing, which saves a certain amount of costs, and the plate making efficiency and printing quality are unmatched by ordinary printing plates. One of the main reasons why digital flexo can survive is that it can be used for high-quality flexo labels. With the improvement of the quality of digital printing plates, the economic advantages of flexographic printing will also create favorable conditions for opening up new markets. At the same time, it will also provide more choice opportunities for printing plants and printing customers, so that customers can get the required prints at the lowest price and the best quality

at present, in East China, fiveorsix packaging and label plate making and printing users have adopted the flexographic direct plate making process and achieved good application results, which is a gratifying phenomenon. We look forward to the vigorous development of flexo direct plate making technology in China, and provide more final packaging label printing customers with lower prices and better quality prints. ※

reprinted from: print magazine

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