Due to its superior structure, sheet-fed offset printing machines have increasingly become the main product of printing machinery, and the requirements for printing quality are also constantly improving. Domestic offset printing machine manufacturers are also developing from the original single-color and two-color machines to four-color and multi-color machines. Each color group of a sheet-fed offset printing machine is mainly composed of a printing plate cylinder, a rubber cylinder, a pressure cylinder, a transfer cylinder and other ink and accessory systems. The running accuracy of the main cylinder directly affects the printing quality, and has a direct relationship with whether there will be overprinting, texture, and uneven coloring. Well-known domestic and foreign printing machine manufacturers have higher and higher requirements for the running accuracy of the main cylinder. The bearing supporting the main roller plays a vital role. In order to improve the quality of the printing machine and add greater added value, many printing machine manufacturers have increased the requirements of the bearing at any cost.
As the history of sheet-fed offset presses has evolved, the main cylinder bearings have undergone many changes. From the earlier brass sliding bearings to roller bearings, from needle roller bearings to roller bearings, from single bearings to combined bearings, from two-ring bearings to three-ring eccentric bearings. The precision of the roller bearing is getting higher and higher, the installation is more and more convenient, and the maintenance is more and more simple.
one. Needle bearing
The rigidity of needle roller bearings is much better than that of tapered roller bearings because of its small roller diameter, and the double-row misaligned needle roller bearings developed by the bearing company make its rigidity comparable to that of copper sleeve sliding bearings. Compared with ordinary needle roller bearings, the needle roller grouping of needle roller bearings used for printing machine cylinder support is higher than ordinary needle roller bearings. The grouping of needle rollers in ordinary needle roller bearings is in units of 2 μm, while the grouping of needle rollers used in printing machines is in units of 1 μm. In this way, by selecting the appropriate grouping of needle rollers, the working clearance of the bearing can be less than 1 μm, which is exactly what high-quality printing machines need. And the grouping of needle rollers used in printing machines can be more than that of ordinary needle roller bearings, so the processing requirements for wallboards can naturally be reduced.
two. roller bearing
The use of needle roller bearings still makes printing machine manufacturers troubled by the need for high-precision machining of the casing, and the need for experienced installers to find a suitable needle roller set. To solve this problem, bearing manufacturers have developed roller bearing supports with integrated flanges on the outer ring. Roller bearings can achieve very good precision and rigidity by preloading. And the inner ring with taper can also be used to adjust the working clearance of the bearing arbitrarily. This solution can completely meet the requirement of zero clearance of the printing machine cylinder bearing. Moreover, the flanged outer ring solves the problems of installation and lubrication for printer manufacturers. Manroland, Heidelberg, Japan Ryubi and domestic Beiren models widely use this bearing. Its roller bearing support solution has become the mainstream solution for roller support in printing machines.
three. integrated unit
Like the automobile industry and other industries, printing machine manufacturers also need suppliers of precision products like bearings to provide simpler modular components to reduce factory assembly errors and time, reduce rework rates, thereby improving efficiency and reducing costs. In order to meet this demand, the bearing manufacturer provides the main roller support with a roller support unit with higher precision and easier installation and maintenance. Such as the three-ring eccentric bearing unit developed by the bearing company. This bearing unit integrates bearings and eccentric sleeves, which not only supports the roller, but also realizes the functions of roller clutch pressure and registration. Its superiority has been widely accepted by printer manufacturersThe models of KBA and Manroland and the new models of Heidelberg have all used this bearing unit on the plate cylinder or rubber cylinder. In the modification work of the old model, this kind of three-ring bearing support has become the first choice. At present, there is no better solution than this bearing unit in terms of performance, installation and use, and maintenance. The use of its labyrinth seal ring and cylindrical rollers enables it to be lubricated with oil or grease, and it is maintenance-free for life. Excellent lubrication also makes the life of this bearing the longest among various schemes. It makes printing machine manufacturers move their precision requirements from their own processing and installation production lines to bearing production lines that produce precision products such as bearings. This is also in line with the intensification of modern industry. The above are various solutions for the support of the main cylinder of the printing machine. Due to its own precision requirements, the printing machine has high requirements for the support of rotating and linear moving parts. The above solutions can completely solve the needs of domestic printing machine manufacturers to develop their own more distinctive products.
