The hottest thermal technology and computer direct

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Thermal technology and computer direct plate making

computer direct plate making technology was first commercialized in gravure and flexographic printing in the 1980s, and began to be applied in lithography in 1990. As early as 1975, the concept of computer direct plate making was first used in electrostatic printing, but it can not meet the needs of commercial printing in terms of resolution or exposure speed. In 1982, the silver salt coated polyester version began to be used for printing with monochrome low registration accuracy about the error shortcomings that appeared when the fatigue testing machine was working. It was not until 1990 that metal lithography, which was suitable for four-color commercial printing and used silver salt technology, began to be used. This kind of printing plate has high photosensitive speed. In 1995, thermal plates with heat transfer or thermal crosslinking were officially launched. In recent years, due to the expanding use of new low-cost and high-energy infrared excipients, the introduction of light tubes has accelerated the promotion of thermal technology

with the continuous development of computer direct plate making technology, the global printing and publishing industry is also growing rapidly. As the third largest industry in the world, the printing and publishing industry itself is also in continuous change. The application and development of computer direct plate making technology has been recognized as one of the future directions of the printing industry. According to the industry research Yearbook vantage strategic market and State Street consultants, by 2003, 18% - 25% of the global demand for printing plates will come from computer direct plate making materials, and the global installed capacity of computer direct plate making machines will increase from 1435 in 1997 to 11500 in 2003. State Street consultants also predicted that thermal plate making machines may account for 53% of the global installed capacity by 2003

what is thermosensitive technology? Thermal technology refers to the type of energy source required for plate imaging, rather than the plate processing process. The image is generated by heat rather than light energy. A more important concept in thermal technology is the critical value, because the critical value is the key to determine whether the plate is imaged. In other words, under the critical temperature, the plate will not generate images and will not react. When the critical temperature is reached, the plate generates an image, and when the temperature exceeds the critical temperature, which is equivalent to overexposure in the traditional printing process, the size and shape of the generated points will not be affected. This fundamentally solves the phenomenon of inaccurate point reproduction caused by overexposure, insufficient exposure or human factors in the traditional plate making process. On the other hand, the concept of critical value of thermal technology is exactly equivalent to the core concept of digital technology, which is not "0" or "1". Whether the plate is imaged only depends on whether the critical value is reached. This makes it possible for digital computers to make plates directly. It can be said that thermal technology is an ideal choice for computer direct plate making to the road to true digitalization

thermal computer direct plate making technology can be generally divided into two categories: (1) thermal crosslinking, (2) thermal melting

the first type of thermal crosslinking plate is a kind of thermal plate with mature technology and large-scale commercial production. Its basic composition is roughened aluminum substrate and thermal crosslinking material coating. The imaging principle of the plate is mainly that the infrared energy is absorbed by the infrared absorption material in the thermal crosslinking coating and converted into heat energy, so that the thermal crosslinking coating will have a crosslinking reaction when the heat energy reaches the critical temperature. When the exposed plate is developing, it needs to go through a preheating process to further promote the curing of the crosslinking reaction, and then it will be developed in the alkaline developer to remove the coating without light

the basic components of the second type of hot melt plates are smooth and invisible roughened aluminum plates, ink friendly layers of hot melt materials and PVA layers (or silica gel). Its imaging principle is mainly to use semiconductor diodes to expose the printing plate, and the hot-melt material at the heated part is combined with the aluminum plate base to form an inkphile layer. The part without light can be stripped or blown off

of course, the thermal technology is still developing continuously. At present, Xinlun composite, a wholly-owned subsidiary of the company, has developed and signed the strategic cooperation and procurement framework agreement with Funeng technology. It is a non flushing thermal printing plate without chemical solution flushing and a waterless printing plate without any flushing process. From the whole research direction of thermal computer direct plate making technology, we can see that thermal computer direct plate making technology is developing in the direction of no chemical treatment and green environmental protection. This also meets the needs of the future green digital printing trend of the entire printing industry

thermal technology, as a relatively mature computer direct plate making technology for large-scale commercial production and application in the current market, is increasingly accepted and recognized by customers in the printing industry. So what are the advantages of thermal technology

(1) open chamber operation

due to the concept of critical value mentioned above, it is possible for the thermal printing plate to operate under the open chamber. Therefore, there is no special film supply box and darkroom, and the operator can clearly control each step of the process. For many years, plate making and printing personnel have been trying to move out of the darkroom. One of the key advantages of thermal technology is that plates can be treated under bright yellow or white light after ultraviolet filtrate wave. This enables the plate makers to get rid of the darkness and see the light

(2) the point is extremely sharp, with high resolution and no point increase

also based on the concept of critical value, which is actually a binary exposure mode, so that the point size can be accurately copied, and the point edge is sharp, with almost no point increase. After studying the thermal CTP plate, GATF found that the point replication accuracy of the plate can reach 0.5% - 98%, and at least 2% - 97%, which is the highest range that the visible light plate can reach when GATF investigated the visible light plate in 1995. The image with 1100 line/inch line accuracy can be obtained by using the thermal CTP plate. And when outputting 600 line/inch images, 1% points can be generated. This provides a strong guarantee for the high-quality printing pursued by the printing industry at present. This characteristic of thermal technology makes it quickly selected by many commercial printers who pursue high-quality printing all over the world

(3) the printability of thermal plates meets the needs of high-quality printing

the printability of thermal CTP plates on printing machines is very stable. After the plate is put on the machine, only a small amount of master paper is needed to quickly achieve the water ink balance, and this balance can be maintained in the printing process, with less water consumption. During the whole printing process, the surface of the printed matter is average, without the worry of getting dirty. Moreover, the printing resistance of thermal plates can reach 150000 ~ 250000 prints without baking, and up to 1million prints after baking. It is suitable for frosted paper printing, which has a wide range of applications and UV ink

(4) non chemical treatment process reduces environmental pollution

another advantage of today's thermal imaging system is that the plate can meet the minimum and hazard free development requirements, and has the development trend without development. Because the imaging principle of thermal plates is different from that of photosensitive plates, on the one hand, the use of silver salt materials in plate production is avoided, on the other hand, the development and application of washed or non washed thermal plates are also avoided in the plate washing process, which will further reduce or eliminate the environmental pollution in the plate making process

(5) the image is very stable

because the imaging of thermal technology only depends on the critical value, the image generated on the plate after exposure is very stable, and the exposed plate can be extended to 6 months before development, which will not affect the quality

(6) easy to use

thermosensitive CTP plate is very similar to traditional PS plate in feeling and processing, and it is completely suitable for existing fountain solution and on-board printing plate adjusting device. This makes it easy for plate makers and printers to accept and operate this digital plate

of course, thermal technology also has its shortcomings, mainly in the need for high-energy laser to make up for the lack of photosensitive speed. However, with the rapid development of laser technology and the development of thermal technology itself, this deficiency does not affect the attraction of the overall advantages of thermal technology to the printing industry. At present, there is a supply of thermal plates in the market to meet the rapid plate making demand of the newspaper market, and its plate making speed can reach up to 360 pieces/hour, which fundamentally changes the view that thermal plates have a slow plate making speed. State Street surveyed printing customers in 3/4 cities in North America and found that 70% of potential buyers planned to use thermal imaging systems when the respondent was limited to only pointing out one type of plate he liked

the future development trend of the printing and publishing industry will be to bid farewell to the darkroom, go digital, eliminate environmental pollution, and finally achieve digital green printing. In the process of the whole printing and publishing industry moving towards digital green printing, thermal computer direct plate making technology will undoubtedly be the most ideal choice. (ren Hui, Beijing Representative Office of Kodak baoliguang printing art group) (from printing technology, 2001, issue 2)

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