The hottest high-quality PS version will coexist w

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High quality PS version will coexist with CTP version

with CTP equipment and a variety of CTP plates successively put on the market, it is undoubtedly a challenge to the original prepress technology and the original PS version printing technology. Will CTP plates replace the existing PS plates? What is the future development of PS version? This is the concern of the plate industry and printing industry

-. Review of PS edition process

offset printing was mostly flat intaglio or flat relief before the PS edition. In the era of Laser Phototypesetting and electronic color separation, flat intaglio and flat relief hindered the development of printing technology. Therefore, as soon as PS edition appeared, it showed that it had obvious advantages compared with traditional plates, Here are a few points that can be recounted:

① PS version changes the original flat intaglio or protein version that can be coated and used immediately into a plate that can be made in advance and stored for a long time, which greatly saves the plate making time and shortens the plate making work that originally required more than - hours to be completed in a few minutes

② the phenomenon of manual plate making in the past has been changed. The good weather resistance of PS plate makes it easy to realize mechanized operation for plate printing and development

③ the printing plate quality has been significantly improved, which is unmatched by the old plate in terms of the resolution and point reduction of photosensitive materials

④ it is possible to change the phenomenon of a large number of plate preparation during the long offset printing in the past. It is possible to print tens of thousands, hundreds of thousands or even hundreds of thousands of plates on a PS plate

from the early 1970s to the end of the 20th century, it took nearly 30 years for China to develop PS version, specifically divided into two stages

the first stage of slow development (1970-1985): in 1975, China successfully studied and built the first sheet type PS plate production workshop. The reason for the slow development is the slow acceptance of new technologies at that time. In 1979, the national offset Book on-site meeting organized by the China Printing Technology Association was to publicize printing technology. Through these powerful technical promotion work, the demand of printing plants for PS version has reached an urgent level for a period of time. Although the production of PS version belongs to the scope of fine chemical technology, due to the urgent need, the printing industry had to start its own work first. In 1982, the "intermediate test project" of continuous production of PS version by rolling aluminum plate undertaken by the China Institute of Printing Science and technology and six single sheet PS version production lines introduced by some manufacturers from Japan, These measures have played a positive role in the start of PS version and meeting domestic requirements

the second stage of rapid development period (1985-2000): in 1985, due to the completion of the first domestic rolling aluminum plate continuous production PS plate production line, and the subsequent introduction of foreign second-hand production line by the second film factory, the production of PS plate has increased rapidly. The number of manufacturers has increased year by year, and the output has expanded year by year. By 1990, the sales volume of domestic PS plate has been close to 10million square meters. In the past 10 years, with the popularity of prepress color publishing systems and the sharp increase in the number of rubber wheel presses and multi-color offset presses, many manufacturers have been encouraged to build PS plate production lines. As a result, by the end of the 20th century, there were nearly 30 domestic manufacturers with annual production of more than one million square meters, and the total production capacity of the country reached a considerable level. According to the declaration of PS version manufacturers, the statistics of relevant departments show that the total production capacity of 32 domestic manufacturers of PS version is more than 80 million square meters, and about 45 million square meters were produced last year, which does not include hundreds of domestic recycled PS version manufacturers with the production capacity of PS version

before the 1990s, China's single sheet PS plate production lines accounted for roughly half of the total output, but now the vast majority of more than 20 PS plate production lines are reel production lines. This shows that it has reached a certain level both in terms of output and technology

II. Analysis of the current situation of PS version

after long-term development, the supply-demand relationship of domestic PS version has basically reached a balance. Specifically, the general quality PS version has a slight surplus, while the high-end PS version is still a little insufficient, and some plates with special properties and specifications still need to be imported. There is still a certain gap between China and developed countries in the manufacturing technology and performance of PS version

(I) in terms of manufacturing technology:

although China now has a production capacity of more than 80million square meters, it is completed by dozens of manufacturers with a total of I companies. Most manufacturers are small in scale and slow in speed. For example, the quality of cement dynamometers is incomplete. In terms of production speed, the speed of production lines is generally about 6 meters/minute, advanced enterprises can reach 10 meters/minute to 15 meters/minute, and the highest speed of imported production lines is 25 meters/minute. Secondly, there is still a big gap in the whitening level. The process control of each link still needs experienced manual operation to maintain the stability of the product

the quality of aluminum plate base, the main raw material for PS plate production, is still insufficient. Although several major aluminum plate manufacturers have made considerable improvements in their products after years of efforts, it still needs to work hard on the stability of batch quality to truly meet the requirements of PS plate manufacturers for plate base quality. Aluminum plate base is one of the basic factors for manufacturing high-quality PS plates. In order to achieve high yield and good product quality, some manufacturers, Do not hesitate to import the plate base to meet the production requirements. In terms of chemical materials, it is not enough. Photosensitive materials and film-forming resins are mostly small workshop production equipment, which has not yet achieved large-scale production, and their quality is difficult to achieve the desired level, which has a certain impact on the stability of PS plate quality

(II) the current product quality of PS version

PS version manufacturers have done a lot of work in strengthening enterprise management, and the quality of PS version has gradually stabilized. The PS version Professional Committee of China printing and equipment industry association has been tracking the quality of PS version for many years, and has carried out nationwide testing every two years, which has played a positive role in improving the quality of PS version

(III) analysis from the aspect of use performance

on the whole, with the shortening of publishing cycle and the acceleration of printing machine speed, people have increasingly strict requirements for the quality of PS version. The biggest requirements of users are stable quality, convenient operation and not easy to waste version. From this point of view, the plate quality still needs to be further improved in the following aspects

(1) stability of plate

it is not too difficult for most PS plate manufacturers to make a batch of PS plates with good quality. However, it is not easy to maintain the same performance for a long time, especially in terms of microscopic performance. In the PS version testing activity last year, we selected a foreign PS version and compared it with the test data in 1998, and found that the two test results were surprisingly similar. In particular, there is little change in the thickness of the photosensitive layer, the thickness of the oxide film and their deviation from the same version, which shows that the quality control of its products is very strict. Users are certainly more relieved when using this kind of plate. Now the stability problem we are talking about is not whether it can be used, but whether it can give the operator greater convenience and reliability when it can be used

(2) exposure and development conditions

foreign high-quality PS plates generally have the characteristics of short printing time and strong adaptability to the developer, that is, a thicker, lighter, new or old development can make a printing plate that meets the public requirements, giving users a sense of enrichment. Most domestic PS versions do not have this performance, so there is a narrow choice in the printing time. Take the positive plate as an example, less exposure may cause the lack of dark tone level, while more exposure will cause the loss of small dots. Although this phenomenon has little impact on general prints, it will affect fine products

(3) Zhenning sealing layer

with the development of printing technology and the improvement of printing quality, high-quality printing all hope to solve the uniformity problem of large-area flat printing. Coating vacuum sealing layer can make the film and the printing plate close better when vacuuming the printing process, so as to prevent the depth difference of printing and publishing. This is what we should pay attention to in the development of domestic PS version

(4) printing of printing plates the hydraulic universal experimental machine produced by Jinan new era assaying Instrument Co., Ltd. can detect the properties of various raw materials

recently, people generally do not require too much for the number of printing plates, but pay more attention to the inkiness of printing plates. A good PS version may use 4-5 sheets of paper to enrich the ink, while a poor PS version may use 10 sheets of paper. This micro performance is also the content of the plate industry. Of course, it is not enough to have a good PS version. It also needs cooperation in the transportation, storage and use of the PS version. No matter how good the PS version is, it cannot be used without following the operating procedures. Now there are offset plate production standards. Through the combination of manufacturing and using the PS version, the overall level of the current PS version can be further improved

III. prediction of the future development of PS version

the emergence of CTP technology and the use of CTP plates are an impact on the conventional PS version, which is normal and gratifying. Because now there are many reasons why CTP technology is much more advanced than the conventional method of drying PS plates, such as:

(1) improve the speed of plate making

CTP technology can scan and image directly on the printing plate through the laser light source, which saves the intermediate link of film, the printing process and the time of plate making. In terms of laser scanning time, it is also much simpler than the conventional printing method. Now many laser plate making machines output 20-30 folio plates per hour, which is unmatched by the conventional printing technology

(2) improve the quality of printing plate and printing quality

the biggest difference between the exposure process of CTP system and PS version is that it does not need a powerful UV light source as PS version, avoiding the exposure process and scattered and refracted light. Most laser light sources use light in a certain wavelength range, so the light energy is concentrated. Because the output resolution of the direct plate making machine can be very high, and CTP plates, whether thermal plates, photosensitive resin plates or silver salt plates, have quite good point reducibility, which provides good conditions for improving the printing quality

(3) conducive to environmental protection

since the adoption of PS version, people have got rid of the pollution of dichromate in the plate making industry, and the pollution of silver salt is inevitable. CTP technology saves the film scanning process and naturally reduces the use of silver salt

The emergence of CTP plates indeed provides a broad prospect for people to choose photosensitive materials. Many photosensitive resins and thermosensitive resins have excellent environmental protection properties. As for thermal ablation plates, their burning residues are well eliminated, and the concentration of developer used in the post-treatment of some photosensitive resins is gradually reduced, which is beneficial to the protection of the environment

(4) it is conducive to get rid of darkroom operation

prepress system processing in the period of photographic plate making or electronic color separation, people can't get rid of the dark operating environment in which Solvay's new high-performance polymer composite factory was established in Changshu, Jiangsu Province in 2012. However, the arrival of digital information and the emergence of CTP technology can make the prepress system work in white light or yellow light factories. Now there are many models of far-infrared laser plate making and UV and UV laser plate making machines. The production of CTP plate can be carried out under the light source similar to the original PS plate, which is conducive to improving the conventional PS plate to achieve the purpose of laser plate making

the above analysis does not cover the input and output information of CTP technology

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