Deputy Director of China Institute of Printing Science and Technology Yue Demao
At the end of the 20th century, the laser direct plate making technology was rapidly developed and developed in the world. Various CTP equipments and various CTP plate materials were born one after another. Some domestic newspapers have begun to use CTP plates to print colored newspapers. This phenomenon explains printing. The development of technology has entered a new stage. CTP technology and CTP plate are undoubtedly a challenge to the original prepress technology and the original PS version. CTP plate will replace the existing PS version? How will the PS version develop in the future? This is a concern for the printing industry and the printing industry. This article analyzes the generation, development and future of the PS version in order to gain a discussion with the industry.
First, the review of the PS version of the process
In the historical process of the development of science and technology, the new technology has always replaced the old technology with its advanced features, and the offset printing plate used by the printing industry is constantly changing. Before the PS version was invented, offset printing mostly used flat intaglio or plano-plate. This kind of plate was quite compatible with the photographic platemaking technology at that time. It did not know how many times advanced than the manual plate making technology in the past. However, in the era of laser photocopying and electronic color separation, the traditional flat-bottom gravure plates and flat plates hampered the development of printing technology. Therefore, when the PS version appeared, it showed obvious advantages compared with the traditional plate materials. point:
The 1PS version changed the original gravure plate, or gravure plate or protein plate, into a plate that can be pre-produced and can be stored for a long period of time. This greatly saved the plate making time, shortening the original plate making work that required more than one hour to several minutes. carry out.
2 It has changed the phenomenon of hand-manufactured plates, and the good weatherability of PS plates has made it easy to realize the mechanical operation of printing and developing.
3 The quality of the printing plate has been significantly improved. The resolution of the photosensitive material and the reproducibility of the dot are unmatched by the old plate material.
4 It has been possible to change a large number of plate editions in the past when offset printing was used in long-term printing. It is possible to print tens of thousands of pages, hundreds of thousands of printings, and even hundreds of thousands of copies per PS plate.
Therefore, China has been developing the 16-character guideline of "laser photocopying, electronic color separation, multicolor offset printing, and binding linkage" for a long period of time as the development direction of the printing industry, and the PS version is the connection between the prepress system and the printing press. Good media. However, the promotion of new technologies requires a process. The PS version has many advantages and is not an overnight event. It took roughly 30 years from the early 1970s to the end of the 20th century to develop the PS version, specifically. Can be divided into 2 stages.
The first period of slow development (1970-1985)
The PS version appeared in the developed countries in the early 1950s, and it was the end of the 1960s and 70s that really spread to China. It was not until 1975 that China successfully studied and built the first single sheet PS production workshop. The reason for the slow pace of development was at the time. Under the circumstances, the delay in accepting new technologies is not allowed. It does not do a lot of propaganda work for the promotion of the PS version. Among them, the National Offset Printing Conference organized by the China Printing Technology Association in 1979 is an excellent example of the promotion of printing technology. . Through these powerful technical promotion work, the demand for PS editions by printing houses has reached an imminent point for a period of time. Although the production of PS editions belongs to the technical scope of fine chemicals, the printing industry had to first launch it first. In 1982, The â€œIntermediate Test Projectâ€ for the continuous production of the PS version of the reel aluminum version undertaken by the Institute of Printing Science and Technology of China and the production of six PS-version production lines for single-sheet PS from some manufacturers are all important products in this situation. The measures played a positive role in starting the PS version and satisfying domestic requirements.
The second period of rapid development (1985-2000)
In 1985, due to the completion of the production of the first PS plate production line with the first reel aluminum plate made in China, and the subsequent introduction of second-hand production lines for the second film factory, the production of the PS plate was rapidly increased. The manufacturers increased year by year, and the output increased year by year. By 1990, the sales volume of domestic PS versions had approached 10 million square meters. In the 10 years of the 1990s, with the popularity of pre-press color publishing systems and the rapid increase in the number of rubber transfer machines and multi-color offset presses, many manufacturers have been encouraged to build PS production lines. At the end of the ZO century, there were nearly 30 factories producing more than one million square meters per year, and the countryâ€™s total production capacity reached a considerable level. According to the PS version manufacturers' own declaration, the statistics of relevant departments show that the total production capacity of the 32 domestic PS manufacturers is now over 80 million square meters. Last year, 50 million square meters have been produced. Although this figure will have some moisture, the actual annual output may be It is around 45 million square meters. This does not include the hundreds of remanufactured PS plates in China that have the ability to produce PS plates. All this shows that the PS version has been flourishing during the past 10 years. The graph below shows the growth of the PS version in China for 25 years.
From the chart, we can see that the output growth in the past 10 years is almost linear, and the production mode has also greatly improved in the last 10 years. Before the 1990s, the production line of the PS type in China accounted for roughly half of the total output. Now the vast majority of ZO's PS production lines are reel-type production lines. This shows that both in terms of output and technically, it has reached a certain level.
Second, the status of the PS version of the analysis
After long-term development, the relationship between supply and demand for the domestic PS version has basically reached a balance. Specifically, the PS version of the general quality has a slight surplus, while the high-end PS version is still somewhat inadequate. Some special performance and special specifications of the material still need to be imported. There is still a certain gap between China's and developed countries in terms of manufacturing technology and performance of the PS version.
(a) In manufacturing technology:
Although China now has a production capacity of 80 million square meters or more, it is completed by dozens of producers. Most of the manufacturers are not large-scale, fast-moving, and have incomplete specifications. The production speed of the general production line is 6 meters. At around / min, advanced companies can reach 10m/min to 15m/min, and the highest speeds for introducing production lines are 25m/min. Secondly, there is still a large gap in the level of automation. The process control of each link still requires an experienced manual operation to maintain the stability of the product.
The quality of the main raw material for the production of the PS plate is still insufficient. Although after several years of hard work, several major aluminum plates have made the products considerably improved. However, it is necessary to truly meet the requirements of the PS plate plant for the quality of the plate base. In terms of the stability of the quality of batches, aluminum plate base is one of the basic factors for the manufacture of high-quality PS plate. Some manufacturers do not hesitate to import plates to meet production requirements in order to achieve high yield and good product quality. In terms of chemical materials, it is not enough. Photosensitive materials and film-forming resins are mostly small workshop-type production equipment. They have not yet been scaled up. Their quality is difficult to achieve to an ideal level, which has a certain impact on the quality of the PS plate.
(B) The current PS version of the product quality
Although there are still deficiencies in the raw materials, etc., the PS version manufacturers have done a lot of work in strengthening enterprise management, and made a gratifying contribution to the stability of the PS version. The China Printing and Equipment Equipment Industry Association PS version The professional committee has been tracking the quality of the PS version for many years and has conducted nationwide inspections every two years, which has played a positive role in improving the quality of the PS version.
From the table, we can see that the 20 samples are pretty good in terms of individual qualification rate, which is also higher than that of 1998 in terms of total qualification rate. In 1998, 20 PS PS versions were also tested, of which all qualified samples were 10 types. The quality rate is deducted by %. In 2000, the number of samples in all 20 samples was increased to 12 and the qualification rate was 60%. This shows that there is an increase in the overall quality, but we must also see that, on the other hand, there are still eight samples with unsatisfactory l-4 indicators.
(III) Analysis from the use of performance
The test performance is generally good enough to reflect the quality of the published material, but the PS version that does not meet the standard can not be said that it can not be used, such as print quality requirements are not high enough or consider the price factor, this version also have to meet the demand one side. However, on the whole, with the shortening of the publishing cycle and the speed of printing presses, the quality requirements for the PS version are becoming more and more stringent. The biggest requirement for users is that the quality is stable, the operation is easy, and the waste version is not easy to produce. From this perspective, the following aspects of the quality of the plate still need further improvement.
(l) Stability of Plates
It is not too difficult for most PS manufacturers to produce a good quality PS version. However, it is not easy to maintain consistent performance over a long period of time, especially in terms of microscopic performance. It will take some work. There are technical issues and equipment issues. In last year's PS version of the testing activities, we had chosen a foreign model of the PS version compared with the previous 1998 test data and found that the two test results are strikingly similar. In particular, the thickness of the photosensitive layer and the thickness of the oxide film and their deviation from the same version have almost no change, which indicates that the control of the product quality is very strict, and users are certainly more assured when using this type of material. Now we have mentioned The issue of stability has not been an issue that cannot be used, but whether it can give operators greater convenience and reliability when all can be used. This is precisely what the domestic version should pay more attention to.
(2) Exposure and development conditions
PS printing process, due to the light source intensity, the printing environment and other factors, it is impossible for each operating conditions completely consistent, the development operation is more affected by the development of the concentration, temperature, development time and other conditions, but also difficult To maintain the same environment, which requires the PS version of the exposure, development latitude is better. Foreign high-quality PS editions generally have short printing time and strong adaptability to developer. That is, the developed thick, lighter, new or old ones can make the printing plate required by the station, giving the user a Seed skin feel. Most domestic PS versions do not yet have this capability, and there is less room for selection during printing. Taking the positive example as an example, less exposure may result in the lack of dark fades, and exposure to a little more will cause the loss of small dots. This phenomenon has little effect on general prints, but will affect fine products. Now.
(3) Vacuum adhesion layer
With the development of printing technology and the improvement of printing quality, fine prints all hope to solve the problem of evenness of large-area prints, and the application of vacuum dense layers will make the film and plate better So as to prevent the phenomenon of different shades from being produced. At present, most of the domestic PS editions have not yet undergone this kind of processing and cannot but say that it is a gap.
Plate printing performance
At present, people generally do not require too much for printing plates, but they pay more attention to the ink-printing and anti-dirty requirements of printing plates. For example, after a printing machine passes over a few sheets of paper, it is possible to make the layout come to ink. This is another function of the evaluation printing plate. A good PS plate may use 4-5 sheets of paper to realize the enrichment of ink. PS version may use 10 sheets of paper, this micro-performance is also the content of the plate industry to improve. Of course, there are not enough PS plates to be manufactured. In the process of transport, storage, and use of the PS plates, they also need to cooperate. Even if the PS plates are not used according to the operating procedures, it is not enough. There are now offset printing plate production standards. As a result, the overall level of the current PS version can be further improved by the combination of manufacturing and use of the PS version.
Third, the prediction of the future development of the PS version
The use of CTP technology and the use of CTP plates is an impact on conventional PS plates. This shock is normal and gratifying. Because it is now possible to come up with a variety of reasons to explain that using CTP technology is much more advanced than using conventional methods to burn PS, 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, eliminating the middle part of the film, eliminating the printing process and saving the time of plate making. The laser scanning time is also much simpler than the conventional printing method. Now many laser platemakers can easily output 20-3O wafers per hour, which is very easy to do.
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