Development and application of new automatic contr

2022-08-17
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Development and application of new automatic control technology of web offset press

with China's entry into WTO, China has introduced many advanced web printing equipment in the world, making China's printing industry enter a high-speed development stage, and the newspaper industry, commercial printing and packaging printing rise rapidly. The companies represented by Heidelberg, Manroland, gaobao, Komori, Mitsubishi, Xiyan, delante Gerber, etc. with the increase of eccentric moment, have introduced web offset printing machines with new technologies, which have the characteristics of high printing speed, high production efficiency, high degree of automation, good printing quality and so on. Among them, the representative new technologies mainly include the following aspects. Shaftless transmission technology shaftless transmission can simplify the transmission device of the printing machine, omit belt transmission, especially gear transmission mechanism, machine operation and operation, installation and commissioning, maintenance, etc. taking each color deck as a unit, the structure is simple and the operation is stable, and the printing quality can be guaranteed even at high speed. In addition, the operation is very convenient, which can save time, avoid engine oil lubrication, and reduce the machine noise. Because the drive combination (such as drive shaft, clutch shaft, etc.) is removed, the manufacturing cost is greatly reduced. After adopting shaftless transmission, the mechanical vibration of a printing unit may be transmitted to the next printing unit through the transmission shaft, which may cause the accumulation of mechanical vibration, affect the transmission accuracy of the printing machine, and make the printing quality not well guaranteed, as is the case with traditional mechanical shaft drive. At the same time, the independent motor drive is very flexible, adding or withdrawing a printing unit becomes very easy and convenient, and the whole system structure is simple. Shaftless transmission can also make the machine control highly automated, making the combination between units more simple and flexible, so as to meet the needs of different customers. From the development trend, the market share of shaftless transmission will be larger and larger, and shaftless transmission will replace the traditional mechanical shaft transmission. Water free offset printing technology in recent years, web water free offset printing technology has been vigorously promoted, and the market share will further expand. Gaobao, Manroland and other companies have launched Web water free offset printing machines. Its characteristics are mainly reflected in the following aspects: first, it completely eradicates the wetting mechanism, makes the ink path control simpler, does not need to consider the ink balance, and the printing production process is easy to be controlled. At the same time, it is conducive to environmental protection without using wetting liquid; Second, the height of the printing press has been greatly reduced. The height of the web offset press is a major problem that puzzles users. Due to the cancellation of the waterway, the height of the printing press can be greatly reduced, and the manufacturing cost and plant height can also be reduced. The height of the same tower structure can be reduced to less than half of the original height; Third, because the wetting liquid is completely eradicated, the paper will not stretch when encountering water in the printing process. The edge of the printing point is highly clear, especially when printing fine lines or various frequency modulation points. In addition, the ink transfer in the area with large ink volume can reach a high field density, without ghost or water roller traces. In addition, the advantage of waterless offset printing lies in its drying and printability of non absorbent substrate materials, which is better than waterless offset printing. Seamless technology the biggest advantage of seamless rubber roller technology is rubber 9 Until the sample breaks or meets the introduction conditions, the leather roller can achieve complete dynamic balance, which is very important to ensure the stable operation of the machine. Adopting this technology requires that the blanket itself is cylindrical, which puts forward new requirements for the manufacturing process of blanket. However, if the manufacturer does not provide this technology or spare consumable materials, this technology will not be widely promoted in the near future. In the past, people always thought that the printing quality of web offset press was much different from that of sheet fed offset press. With the application of seamless technology of web offset press, the stability of drum operation was greatly improved, and the printing quality was very close to that of sheet fed offset press. Many live parts printed by sheet fed offset press in the past can now be completed on the web offset press. The so-called seamless technology refers to the use of seamless rubber cylinder and seamless plate cylinder, that is, the cylinder adopts sleeve structure. The sleeve type blanket and printing plate are very convenient to use, and the replacement operation can be completed quickly on the operation side, which can greatly shorten the version replacement time, and also save the operation of fastening the blanket. After the application of seamless technology, the maximum speed of web offset press is 1.5 times that of ordinary web offset press, and can reach about 1000 meters per minute; The printing width can also be increased by 1.5 times, and the maximum width is more than 1.7 meters; At the same time, the production efficiency can also be increased by more than 2 times. The use of seamless rubber cloth can improve the printing quality. The mechanical vibration caused by the seam of the blanket of the traditional offset press when it meets with other rollers is likely to lead to the production of ink bars. This interference will not only reduce the quality of the print, but also limit the improvement of the printing speed and increase the mechanical wear. At the same time, we have to make a compromise between quality and speed. The application of seamless technology eliminates the printing defects caused by mechanical interference, and is the best way to completely avoid the vibration caused by the joint between the plate cylinder and the rubber cylinder. In addition, there is no gap between the plate cylinder and the rubber cylinder, so there is no need to add shoulder iron (roller pillow), and the rubber cylinder can be made stronger, which solves the deformation problem of the cylinder. Therefore, the double diameter cylinder is not necessary, and can be made into a single diameter cylinder. Seamless blanket can effectively reduce waste in the printing process. On the premise of equal drum circumference length, the printing area of the web offset press using seamless blanket is obviously larger than that of the traditional press, which can save tens of thousands of yuan of paper cost every year

sleeve technology

delant Gerber introduced offset printing technology with variable sleeve size, referred to as VSOP technology. This technology allows customers to flexibly replace sleeves of any size on the plate cylinder and rubber cylinder of the offset press without replacing the entire printing unit. Using this variable sleeve size technology, it is convenient and fast to change the printing size. It only needs a few simple steps to complete the replacement of different prints, even for short edition printing; The price and supply time of sleeve and printing plate are far more than that of flexographic printing and gravure printing. It is five times stronger than carbon steel, cheaper and faster. The printing quality is slightly worse than that of traditional offset printing, but it is comparable to or even better than flexographic printing and gravure printing; At the same time, the circumference of the plate cylinder and rubber cylinder can be changed steplessly within a certain range, which makes the printing machine extremely flexible and can almost meet the printing of any different substrate materials (such as film, aluminum foil composite materials, etc.). In the past, sleeve technology has rapidly improved flexographic printing technology. At present, sleeve technology has entered the world of offset printing technology. Inkless key technology ink volume adjustment is a relatively frequent operation. The inkless Key Technology launched by gaobao company on its waterless web offset press completely solves the problem of ink volume adjustment. The core of this technology is to use a corrugated roller to realize inking and inking

needle free technology Heidelberg company has developed an advanced needle free folding device to match the higher speed of the printing unit, and it is closely connected with the performance characteristics of paper saving provided by seamless blanket. Needle free technology also has the characteristics of saving paper. Because there is no need to cut off the paper after punching a needle hole, the non printing part can be minimized, which complements the feature of increasing the printing area provided by seamless blanket. These new technologies are combined with the design of triangle folding device to provide users with more flexible and diverse products to meet various needs. With the application of various new technologies, the web offset press has made great progress, especially the application of digital technology has promoted the offset press to a higher level. DICOweb launched by Manroland company is the representative of Web digital printing machine. It uses heat transfer imaging technology to image directly on the plate cylinder, and the production time of each plate is less than 10 minutes. With this technology, the printing plate can be replaced without using film, so as to ensure the quality of printing products, save a lot of auxiliary time and improve productivity. Web digital printing machine is especially suitable for short version printing, which is simple and convenient to operate, so it will occupy a certain market in the field of commercial web printing. In addition, taking advantage of the original technical advantages of offset printing, combined with the pre press and post press integration function formed by digital technology, modular design, digital printing software and digital pre press and post press processing system are added to the original offset printing system, which is widely used in rubber, plastic, leather, wire, cable, scientific research and other institutions. The advantages can also realize variable data printing, and meet the on-demand printing of high quality and high productivity. Newspaper printing must properly deal with the page number, printing number and other issues of newspapers according to the final production task. With the help of CTP and full page mosaic technology, the direct plate making from the digital database to the plate cylinder will be finally realized, and the prepress and printing will be further connected. Therefore, the digital technology will be further developed on the web offset press

source: China Automation

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