Talking about the new technology and development trend of web offset printing machine

With the development of China, many advanced web printing equipments have been introduced in the world, which has made China's printing industry enter a stage of rapid development. Newspaper, commercial printing and packaging printing have rapidly emerged printing technology. Companies such as Heidelberg, Manroland, KBA, Komori, Mitsubishi, West Research, and Delant-Gerbel have introduced web-based offset presses with new technologies, all of which have high printing speed and high production efficiency. The characteristics of high automation and good printing quality, among which the representative new technologies mainly have the following aspects.

Shaftless drive technology

The shaftless transmission can simplify the transmission of the printing machine, eliminating the belt drive, especially the gear transmission mechanism. The operation and operation of the machine, installation and commissioning, maintenance, etc. are in units of each color group, and the structure is simple and stable, even at high speed. In the case of printing quality can also be guaranteed. In addition, the operation is very convenient, saving time, eliminating oil lubrication and reducing machine noise. Because the drive combination (such as drive shaft, clutch shaft, etc.) is removed, the manufacturing cost is greatly reduced.

After the shaftless transmission, the mechanical vibration of one printing unit can be transmitted to the next printing unit through the transmission shaft like the traditional mechanical shaft drive, which causes the accumulation of mechanical vibration, affects the transmission precision of the printing machine, and makes the printing quality Not a good guarantee. At the same time, the independent motor drive is very flexible, and it is very easy and convenient to add or remove a printing unit, and the whole system has a simple structure. The shaftless drive also enables highly automated machine control, making the combination between units simpler and more flexible, thus meeting the needs of different customers. From the development trend, the market share of shaftless transmission will become larger and larger, and the shaftless transmission will replace the traditional mechanical shaft transmission.

Waterless offset printing technology

In recent years, the web waterless offset printing technology has been vigorously promoted, and the market share will be further expanded. Companies such as KBA and Manroland have introduced web-based waterless offset printing presses. Its characteristics are mainly manifested in the following aspects: First, completely eliminate the wetting mechanism, make the ink path control more simple, do not need to consider the ink balance, the printing production process is also easy to control, and the use of dampening fluid is not conducive to environmental protection; The height of the printing press is greatly reduced, and the height of the web offset printing machine is a big problem that plagues the user. Due to the elimination of the waterway, the height of the printing machine can be greatly reduced, and the manufacturing cost and the height of the factory can also be reduced. The height of the structure can be reduced to less than half of the original height; thirdly, due to the complete eradication of the wetting fluid, the paper will not be exposed to water during the printing process, and the edge of the printing dot is highly clear, especially in the printing of fine mesh or This superiority is more pronounced in various FM outlets, and the ink transfer in the large ink area can achieve high solid density without ghosting or water roller marks. In addition, the advantage of waterless offset printing is that drying and printing suitability for non-absorbent substrates are superior to water offset printing.

Seamless technology

The great advantage of the seamless blanket cylinder technology is that the blanket cylinder can achieve full dynamic balance, which is very important to ensure the stable operation of the machine. The use of this technology requires the blanket itself to be cylindrical, which puts new demands on the manufacturing process of the blanket. However, if the manufacturer does not provide this technology or spare consumables, this technology will not be widely promoted in the near future.

In the past, people always thought that the printing quality of web offset printing machine was much different from that of sheetfed offset printing machine. With the application of seamless technology of web offset printing machine, the stability of drum operation was greatly improved, printing quality and sheetfed offset printing. The machine is very close, and many of the jobs that were previously printed on sheetfed offset presses can now be completed on web offset presses.

The so-called seamless technology refers to the use of a seamless blanket cylinder and a seamless plate cylinder, that is, the drum has a sleeve structure. The sleeve type blanket and the printing plate are convenient to use, and the replacement operation can be completed quickly on the operation side, which can greatly shorten the plate changing time and also eliminate the work of fastening the blanket. After applying seamless technology, the high speed of the web offset press is 1.5 times that of the ordinary web offset press, which can reach 1000 meters per minute; the printing format can also be increased by 1.5 times, and the large format width is over 1.7 meters; Production efficiency can also be increased by more than 2 times.

Use a seamless blanket to improve print quality. The mechanical vibration generated by the seam of the traditional offset printing machine blanket when it meets other rollers is likely to cause the production of the ink bar, which not only reduces the quality of the printed matter, but also limits the printing speed and increases the mechanical wear. At the same time, we have to compromise between quality and speed to choose printing technology. The application of seamless technology eliminates the printing defects caused by mechanical interference and is a good way to avoid vibrations caused by the joints of the plate cylinder and the blanket cylinder. In addition, there is no gap between the plate cylinder and the blanket cylinder, no need to install a shoulder iron (roller), and the rubber cylinder can be made stronger, thus solving the deformation problem of the drum, so the double diameter drum is gone. If necessary, it can be made into a single diameter roller.

Seamless blankets can effectively reduce waste during the printing process. Under the premise that the circumference of the drum is equal, the printing area of ​​the web offset press with seamless blanket is obviously larger than that of the conventional printing machine, which can save tens of thousands of paper cost printing technology every year.

Sleeve technology

Delant-Gerbel has introduced variable sleeve size offset printing technology, referred to as VSOP technology. This technology allows customers to flexibly change sleeves of any size on the offset cylinder and blanket cylinder of the offset press without having to replace them. Printing technology for the entire printing unit. With this variable sleeve size technology, the replacement of the print size is convenient and fast, and the replacement of different prints can be done in a few simple steps, even in short runs; sleeves and plates The price and supply time are far cheaper and faster than flexographic printing and gravure printing. The printing quality is slightly worse than traditional offset printing, but it is enough to match the flexographic printing and gravure printing, even slightly better; The circumference of the plate cylinder and the blanket cylinder can be steplessly changed within a certain range. The printing machine becomes extremely flexible and can almost meet the printing of any different printing materials (such as film, aluminum foil composite, etc.). In the past, the sleeve technology has rapidly improved the flexographic printing technology. At present, the sleeve technology has entered the world of offset printing technology.

No ink key technology

Ink adjustment is a relatively frequent operation. The inkless key technology introduced by KBA on its waterless web offset press completely solves the problem of ink volume adjustment. At the heart of this technology is the use of an anilox roll. The upper mesh is used to achieve ink and ink.

Foldless needle technology

Heidelberg has developed an advanced needleless folding device to match the higher speed of the printing unit and to match the paper-saving performance characteristics provided by the seamless blanket. The non-folding technology also has the characteristics of paper saving. Since it is not necessary to cut the hole on the paper, the non-printing part can be reduced to a small size, which complements the increased printing area provided by the seamless blanket. These new technologies are combined with each other. Together with the design of the triangular folding device, the user is provided with a more flexible and diverse product to meet various needs.

Digital technology

With the application of various new technologies, the roll paper offset press has been greatly developed, especially the application of digital technology has promoted the development of offset presses to a higher level. MANROLAN's DICOweb is the representative of web digital presses. It uses thermal transfer imaging technology to image directly on the plate cylinder, and each plate is produced in less than 10 minutes. This technology eliminates the need to change plates and eliminate the use of film, thus ensuring print quality while saving a lot of auxiliary time and increasing productivity. The web digital press is particularly suitable for short-run printing, which is simple and convenient to operate, and therefore will have a certain market in the field of commercial web printing.

In addition, using the original technical advantages of offset printing, combined with the digital technology to form the pre-press and post-print integration functions, the modular design, digital printing software and digital pre-press and post-press processing systems are added to the original offset printing system. Variable data printing can also be achieved with network advantages to meet high quality, high productivity on-demand printing.

Newspaper printing must handle the page number and number of newspapers in a good way according to the final production task. With CTP and full-page imposition technology, the direct plate-making from the digital database to the plate cylinder can be realized, and the pre-press and printing can be further connected. Therefore, digital technology will be further developed on web offset presses.