Advantages and disadvantages of waterless offset p

2022-07-24
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Analysis on the advantages and disadvantages of waterless offset printing as a new printing technology, waterless offset printing technology was introduced into China in the early 1990s and attracted extensive attention in the printing industry. However, due to various reasons, it is only used in a few places in China. The author has the honor to work in Beijing Wenxiang Color Printing Co., Ltd., which is a joint venture between Beijing foreign language printing factory and Japan wenxiangtang Co., Ltd. By using this printing method, the effect is better and the corresponding economic return is obtained

the origin of waterless offset printing in the early 1960s, 3M company of the United States first applied for a patent for waterless offset printing technology and industrialized it. The emergence of this technology caused great shock in the world printing industry. However, because some of the technical problems were not well solved, 3M company stopped the production of waterless offset printing plates in the early 1970s. However, the idea of this technology inspired many researchers of this technology in the world printing industry, Along this line, they actively and continuously explore and forge ahead. Through unremitting efforts, the waterless printing technology has made great progress. Among them, Toray company of Japan first industrialized the waterless offset printing plate and published the patent. In the mid-1970s, the waterless offset printing plates of Toray began to be officially sold. In addition to making great efforts in plate materials, they also made great efforts in ink. After repeated improvement, they solved problems encountered by 3M company in the production of waterless printing plates, such as development, film strength and storage stability, so that 3M company has always been in a leading position in the technical field of waterless offset printing

From 1980s to 1990s, Japan wenxiangtang Co., Ltd. changed water printing to anhydrous printing, and realized computer management of production scheduling control. The company has long hired authoritative developers of anhydrous offset printing technology as technical consultants, so that the adoption rate of anhydrous offset printing in the company reached about 85%, and the product quality level and economic benefits of the company have been greatly improved, In the mid-1990s, wenxiangtang Co., Ltd. and Beijing foreign language printing factory jointly established Beijing Wenxiang Color Printing Co., Ltd. at the beginning of its establishment, the company mainly focused on waterless offset printing technology and became a test field for waterless offset printing technology in China

waterless printing can be divided into: from the first generation in 1977, the second generation in 1987 to the third generation in 1994, it has developed by leaps and bounds since it was put into industrialization: the newer generation of waterless offset printing machines, inks and plates are constantly developed. In the past 20 years, the change of equipment and raw materials is only the continuous improvement and improvement of this printing method. Wenxiang color printing company, where the author works, uses the most original first generation method of waterless printing, that is, waterless printing realized by using non cooling printing machine. It is precisely because of this that the advantages and disadvantages of waterless printing, a new printing technology, are fully reflected, so that users can experience the essence of waterless printing in their actual work

principle and process of waterless offset printing

people who have been in contact with printing know that offset lithography adopts the principle that water and ink repel each other. On the same metal lithography, there is both water and ink, so the key factor for the quality of printed products is the balance between water and ink, and the water supply system is the direct factor for many disadvantages in water printing

waterless printing, as the name suggests, is to remove the water factor compared with the current lithographic watery offset printing. Its basic features are: ① faithfully reproduce the image on the positive picture on the waterless offset printing plate. ② Faithfully reproduce the image of the printing plate on the substrate. To put it simply: the water free offset printing plate adopts the oil repellent property of silica gel. The water free version is coated with a layer of silicone adhesive layer on top of the photosensitive layer. Before exposure of the unused version, the photosensitive layer and the silicone adhesive layer are firmly adhered together. After the printing plate is sensitized, the photosensitive part (not the picture and text part) produces a light polymerization reaction, so that the upper silicon cave adhesive layer adheres and is fixed

The key to the development of anhydrous offset plate is to cut off the silica gel layer equivalent to the image and text part. The shear force is stronger than the adhesive force between the silica gel layer and the photosensitive layer of the image and text part. The silica gel layer of the image and text part can be removed by applying it to the interface of the two layers. Of course, first of all, it uses appropriate p.p.g (polypropylene glycol) and p.e.g (polyethylene glycol) to make the photosensitive layer of the picture and text part (unexposed part) swell, and the silicon cave adhesive layer floats up. After the adhesion between the two layers is greatly weakened, the nylon brush is used to apply a shear force to the silica gel layer at the interface to remove it. This is how the waterless printing plate is made

advantages and disadvantages of anhydrous offset printing

in order to make the printed matter closer to the original and make the printing density of various colors higher than the originally set density, the key technology is to expand the control point. The first means of expanding the control point is to modify the gradient curve in the plate making process, and the second is to control the exposure time in the plate printing process, so as to slightly reduce the printing point. This is a common method for watered plates, while the waterless offset plate is a flat intaglio structure, which can copy points from 2-3% high light to 97-98% dark, and the point reproduction range is 95%. In non horizontal printing, due to the absence of the influence of fountain solution, the number of dot expansions is small. At present, the number of dot expansions in the middle tone is about 7-8%. This amount will not change greatly even if the ink thickness increases. Compared with the PS version, waterless offset version of the hierarchical copy curve can obtain a copy effect similar to that of the original film. Therefore, waterless offset printing is obviously better than waterless offset printing for control point expansion

because the water factor is removed, the dot ink of the product is full, and the pictures and texts are bright and bright. It eliminates the printing caused by water, which can quickly determine the required range of brush ink color unevenness, ink emulsion stains, water spots, dirty reverse side, water roller bar printing and other quality problems. In addition, the adjustment and maintenance of the water system can also be omitted in the mechanical adjustment. Without the factor of water, there is no need for fountain solution, water roller system and related accessories. Therefore, the preparation time before startup is shortened, the consumption of paper is saved, and the printing cost is reduced

on the premise of ensuring the environment required for water free printing, due to the special structure of water free printing plate, the printing resistance is improved. At present, it is generally about 100000 or even higher. When the printing plate needs to be retained, there is no need to wipe the glue. Just clean the used printing plate with gasoline and store it away from light. It is easy to retain, and the retention period is much longer than the watermarked version

in the small batch printing industry, waterless printing has good compatibility. Even today, with the rapid development of waterless printing equipment, as long as you have water printing equipment and machinery, you can change to waterless printing without using water rollers. At present, the waterless printing equipment of our company is the waterless printing machine produced by the original Japanese Komori company, and the printing effect is also relatively ideal, especially in spring and autumn

since the waterless printing technology is obviously simpler than the watered printing, it is convenient for the operators to master the technology, which is conducive to the stable quality of printing products and reduces the labor intensity of workers. It reduces the erosion of water on the printing machine parts, especially several rollers, and prolongs the service life of the machine

the number of machine operators has been reduced. After the four open four-color printing machine used by the company adopts waterless printing, the number of people including the receiving machine has been reduced from four when there is water to two at present

there are still many imperfections in waterless printing. For example, since the paper used for anhydrous printing is the same as the paper used for other printing methods we usually use, when using the special anhydrous printing machine planned to be put into operation at the end of 2018 in the non project phase 1 project, the required ink viscosity is very high, so the phenomenon of paper plucking and rubber coating cannot be avoided. At this time, the phenomenon of static electricity is also easy to occur, so the humidity requirements for the peripheral environment of printing are relatively strict, (among them, the humidity below 100g or offset paper is more obvious). Generally, the humidity is required to be between 50% and 60%. Therefore, the company is easy to master the wet temperature in spring and autumn in anhydrous printing

temperature control is more critical in the company, because the company uses the non cooling type. The split of the ink causes heat, which is easy to soften the ink and dirty the printing plate. Therefore, in the first generation of waterless printing, the ink can be divided into H, m and s, i.e. hard, medium and soft, so that it can be used for different seasons or small temperature changes, Generally, the temperature of the external environment during printing should also be controlled between 18 ℃ ~ 22 ℃

the quality of waterless offset printing products depends on ink to reflect and adjust. Therefore, in addition to the quality of the ink, the ink supply system, especially the pressure between the ink rollers, is also important. At the same time, there are also considerable requirements for the pressure between several rollers. Excessive roller pressure is easy to cause not only the ink bar, but also the dirty layout. Too small roller pressure will lead to poor ink transfer and reduce the product quality. Therefore, the pressure between the ink roller and the printing roller must be adjusted in strict accordance with the requirements

for the defects of the waterless printing plate or the residual coating part, the special cleaning solution can be coated, and the defects can be eliminated with the help of the new silicon cave adhesive film. This kind of dirt removing liquid is a polycondensation cross-linked silicone gel liquid decomposed by adding water through the moisture in the air. In order to have both the stability in the preservation process and the dryness after coating, a special coating tool must be used; In addition, in the process of coating, namely "dirt removal", it is also necessary to master the thickness of the silicon coating solution. If it is too thin, it will not get dirty or it will be rubbed off soon after being printed and pressurized. If it is too thick, the coating layer will be too high and higher than the original silicone layer of the non image part, resulting in ink scraping and dirt, which deviates from the original intention of coating

at present, non developing countries must rely on imported companies for some raw and auxiliary materials such as plates and inks, while the products of non developing countries cover plastics, polyurethane, silicone, etc., with relatively high costs. According to the company's use, a dry quarto version without drying is nearly 90 yuan after tax, while a folio PS version produced by a joint venture is only about 20 yuan

waterless offset printing market and analysis

at present, waterless refresh technology and new materials are developing rapidly in the world. The use of waterless offset printing is also increasing. In Japanese relief companies, waterless offset printing technology has been used on high-speed rotary machines. According to other data, now the market share of waterless offset printing in Europe is 6% ~ 7%; In the United States, it is 5% ~ 6%. According to a report from Fogra in Germany, the market share of waterless offset printing will increase to 10% by 2006. In Asia, waterless offset printing market, except Taiwan Province of China, which accounts for a considerable proportion in printing, also has a small number of applications in some Southeast Asian countries (these are not reported in detail). In the mainland of China, except for oneortwo provinces and cities such as Beijing, there is no other place to use it. The market share is about a few tenths of ten thousand. Therefore, waterless offset printing technology in China can only be regarded as a strange new technology. Why has there been no progress in China's printing industry since 1993? The main reason is that the localization of plate materials has not been solved. The cost of importing from Japan is 3-4 times higher, and the cost of ink is also 30%. Therefore, many enterprises can only flinch from the waterless offset printing technology in the current period of continuous decline in the printing industry

To sum up, the advantages of waterless printing outweigh the disadvantages, and its economic benefits are obvious and easy

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