This article was provided by Zhao Guangye, Senior General Manager of Zhao Xuan, Deputy General Manager of Zhaodi Printing Machinery Co., Ltd. 1. Mechanical properties of offset presses For the paper feeding part of the modern high-speed sheet-fed multi-color offset printing machine, it must not only ensure the stability and accuracy of the paper feeding during high-speed printing, but also fully consider various factors to adapt to different types and formats of printing material. Komori's paper feeder adopts an eight-nozzle design, which can stably convey paper with a thickness of 0.04 ~ 0.8mm, while the paperboard is still a step belt. It is equipped with a movable paper brush and paper. Wheel, this arrangement also has good adaptability to printing materials that are not very standardized or of less than ideal quality. In order to ensure the accuracy of paper feeding and prevent paper feeding failure and paper waste, Komori uses a combination of mechanical, photoelectric and inductive methods to control the skew, double and empty sheets in the paper feeding process. The paper delivery mechanism does not adopt the currently popular hem type, but is still the hem type. At present, the printer speed can reach 15,000 sheets / hour, and the paper delivery is stable and accurate. There is no such thing as unstable paper feed and printing speed, and a paper feed (forward paper) roller is also omitted. Printing can be completed in only 8 paper transfers, of course, there is a further guarantee of printing quality. In addition, the anti-scattering tail device installed on the oscillating paper delivery shaft can compensate for the loose paper tail, which has practical significance for domestic users. The arrangement of the printing cylinders is not important, because both the "seven" and "five" o'clock layouts have their own short and long lengths. From the actual effect, the machines with different arrangement methods have little difference in printing quality and machine operability. Moreover, there are two layouts in the product lines of some manufacturers. The advantages of double-diameter impression cylinder and double-diameter paper transfer cylinder in ensuring the quality of printing and expanding adaptability have been proved by practice. Komori sheet-fed offset printing presses are also in this way, but the current air cushion type paper guide method is not used in the paper guide system, but a roll-over paper delivery roller with a special cloth for preventing smudging is used to ensure The printed sheets are not scratched or scratched during the transfer process. Komori is currently the only manufacturer that has two methods of front and back printing, namely double-sided printing with flip and double-sided single-sided gripper printing, and is the only commercial manufacturer of double-sided double-sided offset printing machines. Manufacturers, this model is aimed at the color book and magazine printing market. Since 1998, this model has been installed in more than 40 units worldwide. From the perspective of manufacturing and user use, the double-sided printing with flip in these two double-sided printing methods due to the large number of paper transfers, the accumulation of mechanical wear errors caused by long-term use will affect the quality of the printed product and is inconvenient Maintenance, secondly, there are special requirements for the quick-drying of the first four colors of ink. The double-sided single-grip double-sided printing method, because it is a paper holding on one side, adopts the imprinting to imprinting pass-through paper method. In order to avoid the problems of dirty, mouth, positive and negative registration faced by the flip printing. In addition, this single gripping method has a strong adaptability to the domestic non-standard format paper. The shaft, gripper structure and material on the transfer paper cylinder are important for ensuring registration accuracy, reducing ink color instability, adaptability to printing materials and durability of the printing machine. Komori uses large-diameter torsion bar teeth The shaft is used to strengthen the strength. The gripper pad adjustment device can respond quickly to thick and thin paper. The gripper is made of carbon steel coated with emery, which can greatly enhance its durability. There should be a reason for the ink and water delivery system of the printing section, whether it is a long ink path or a short ink arrangement. Komori uses a long ink path method. Four different diameter form rollers and four ink channeling rollers provide a uniform and uniform ink film for the layout. The ink channeling roller is a copper roller, which has excellent ink transfer performance and good heat dissipation. , Easy to clean. The water delivery system adopts a five-roller continuous water supply design with reverse water transfer. Its characteristic is that it can provide a stable, uniform and minimum amount of fountain solution directly to the layout, and it can do alcohol-free printing without changing the configuration. The various protection devices adopted by different manufacturers in the paper collection section are designed to prevent scratches and scratches on printed products and shorten the time spent on post-printing processes. For example, the double anti-print sheet deflection device used by Komori and The de-roller (which can restore the flatness of the downward paper edge), as well as the double-receiving device that can automatically separate the faulty printed sheets. 2. Automatic control and others For modern offset printing, its automated procedures and printing monitoring capabilities are important signs of its advanced nature. For example, the automatic job preparation and presetting functions can quickly and accurately register and color-adjust different printing materials without relying on experience. Among them, there are two ways to adjust the diagonal of the printing plate, which are related to the structure and design of the machine itself, unlike the introduction of related materials. Komori uses the axial deflection of the plate cylinder. This is because Komori's roller bearings are processed and installed by special materials and proprietary technologies, which can adjust the deflection of ± 0.2mm while avoiding the accuracy of the cylinder. Cause long-term damage. Sheet-fed multi-color offset presses have very high requirements for durability, because any small mechanical and electrical failures will interrupt printing and reduce production efficiency. Therefore, their ability to work overload and durability should be valued. Judging from the current situation, the structure and design of offset presses are relatively mature. Common failures mostly occur in electrical control, but this was not the case 8 to 10 years ago. At that time, failures were mostly mechanical. Therefore, at present, all manufacturers are working hard on the stability and reliability of electrical control technology, and also applying some technical features and functional configurations of web offset presses to sheet-fed offset presses. Komori believes that domestic offset press users' awareness of products is more focused on the scope of adaptation to thick and thin paper, the stability of offset presses, cost performance, product sales and service support, and the technological advancement of the product itself. Dumbbell Bench,Incline Dumbbell Bench,Dumbbell Flat Bench,Dumbbell Stool NINGBO CHEN WEI SUPPLY CHAIN MANAGEMENT CO.,LTD , https://www.chenweisupply.com