Offset presses are widely used in today's various countries because of their good printing quality, flexible and wide application range, convenient plate making, and low price of consumables. The new or improved offset presses that offset press manufacturers have introduced in recent years are benefiting from the effects of computer technology, fiber optic transmission, and digital and network technologies, which have led to a significant increase in the printing precision of offset presses and a more mature control technology. Intelligent management became even more perfect. This sign was particularly prominent on Drupa2000. The main performance is to enhance the stability and reliability of the mechanical properties of the offset press, increase the degree of automation of the automation operation, increase production efficiency, increase efficiency, and apply more ergonomic principles. In addition, some excellent design, structure layout and function configuration of sheetfed and web offset presses are interpenetrating, while flexographic short ink paths and ceramic anilox roller technology, gravure and embossed ink are thick and uniform. The effect was also married into a modern offset press. We may wish to listen to some of the views of the technology and product representatives of several world-class offset press manufacturers on the state of modern offset press technology, product functions, and market applications. Heidelberg's technological development status This article is provided by Mr. Shao Yuanlin, General Manager of Speedmaster, Heidelberg (China) Co., Ltd. Mechanical Structure of Offset Presses The main prerequisite for efficient production of sheetfed offset presses is a stable and reliable paper feeder. Therefore, all major offset press manufacturers have incorporated it into their own production system. At present, according to different printing materials and specifications, the sheet feeding method adopted by the sheet-fed offset press—step belt type vacuum suction belt type feeding under the standard feeding paper has its own advantages. The reason is that it has a stable structure. Accurate paper feed and guide lines form a right angle. In addition to the paper roll, brush and paper feeder, it can be widely applied to a variety of substrates, such as corrugated paper and micro-crimped paper. This is important for printing papers with poor specifications and performance. Below the medium format, such as the four-open and eight-opening offset press on the use of suction belt conveyor, because the operation and adjustment is simple and easy. In order to adapt to the status quo of short-run jobs, that is, frequently changing jobs and changing paper sizes, Heidelberg has introduced a preset paper feeder with higher reliability and speed. This system retains the structure and methods of traditional walking belts, but in many aspects has been optimized to make the system more tight and easy to automate the operation and control. One of its characteristics is that the paper forms an accurate method structure with the front gauge and side gauges. In order to ensure the reliability and speed of paper feeding, the second is that the pile of paper is upgraded stepless rather than stepped, so that the actual thickness of the paper can be increased to maintain a stable distance from the suction nozzle; Semi-closed systems have a positive effect on noise reduction, dust protection, and maintenance free. In addition, Heidelberg adopts the adjustment of the tumbling-type tooth decay speed to automatically correct the paper in the range of 200° to 312° instead of the traditional fixed angle correction. The roller layout and arrangement of the printing section is one of the hot topics discussed in the industry right now. In fact, in the face of diverse and specialized market demands, whether it is "seventh" or five, there are irreplaceable features. The feature of “seven†o'clock is that each group of papers is handed over after printing, and it is advantageous for arranging large drums such as double-diameter impression cylinders, which is very suitable for thick paper printing (mainly packaging printing) requiring large curvature. It is useful, but practice shows that this method is not perfect for publishing and commercial printing based on thin paper. The "five" clock method is good for arranging better ink routes. Heidelberg follows the natural requirements of market segmentation and uses the "seven" dot roller arrangement for SM102 and CD102. SM102 is a three-roller (A single-diameter, double-diameter, and B-single-path) transfer and inversion system, and the blanket cylinder, impression cylinder, and A single-pass transfer cylinder are almost in a “one†shape layout, which is very favorable for printing paper. The transfer (even if the full version of printing is also very good); CD102 is a double-diameter impression cylinder and a three-pass roller as the transfer system, its advantages are well known. For the SM102, Heidelberg also did not use an air-guided paper guide system. Instead, it used a metal sleeve with an ultra-fine irregular chrome-plated bump (the so-called Micro Jaket device) mounted on a reverse-printing impression cylinder. In order to prevent the dry surface in the printing press, filthy dirt. Heidelberg did not adopt the air-cushion transmission method on the device for preventing dirt and scratches printed after turning over. Instead, it used the method of applying a silicon metal anti-fouling film, a super blue cloth and a steel sleeve on the transfer paper roller. means. In fact, one of the focuses of the battle between the number of rollers and the way of arrangement is the influence of the paper misalignment caused by the difference in the number of times of paper transfer to the print quality. Heidelberg's view is that the number of paper transfers does not have a substantial impact on print quality. The key is to consider the accuracy of the transfer structure itself. Practice has proved the correctness of this view. For walk-and-go rollers, the specific structural characteristics of the drum, transmission gears, bearings, etc. should be determined. Judging from the current level of offset press manufacturing technology, walking roller printing can ensure high-quality printing, low noise operation and the best durability of the machine. Heidelberg's ink inking and dampening system is also very characteristic. First, it has 21 ink rollers. It adopts the front vertical type (the first two ink inking rollers inking, the latter two ink inking rollers are all ink), and the shortest ink path has only 8 ink rollers. , can achieve rapid response to ink flow. The dampening system is a five-roll type structure and has an automatic speed compensation function, which has the advantage of maintaining the stability of the water supply while quickly realizing the ink balance and changing the printing speed. When printing a small-format or large-area non-image area job, the need for fountain solution is less than that of a normal job, and therefore the water supply volume of the fountain roller is correspondingly reduced. Heidelberg's practice is to partition the fountain roller relative to the (32) ink zones and use an axially adjustable blower fan to evaporate the excess fountain solution. The paper delivery section has an important influence on the speed of production of offset presses and the quality of printed products. Heidelberg has introduced a blowing air guide device that allows paper to be smoothly introduced into the paper cassette without scratches, while the dual dusting device not only makes the paper cassette stable and neat, but also saves up to 30% of the powder. Secondly, the automation level of the automation and integrated offset press is one of the key points of the competition among all the manufacturers. The purpose of its development is to free the operator from daily complicated manual operations, thus concentrating their efforts on printing quality and efficiency. At the same time, it also allows users to have the means to compete in the environment in which short-term operations have soared. The further improvement of the automation level of offset printing presses is based on the continuous improvement and optimization of the machine's mechanical performance and electronic control level. It can realize the pre-adjustment of the printing material specifications, realize the automatic monitoring and control of printing quality, and fully digitalize the configuration. The electronic display system realizes integrated operation and management in order to achieve better quality, shorter preparation time, less maintenance time, and higher output. Heidelberg has gained industry acclaim by adding functions such as image color control and automatic on-line register control in these aspects. In order to avoid the change of printing color and ensure stable printing quality, Heidelberg first used spectral spectroscopy to scan images and simultaneously perform online color adjustment. The online automatic registration and registration system not only performs quick fine-tuning and registration at the beginning of printing, but also continuously monitors and corrects during the entire printing process, which can greatly reduce the machine's accurate stop time and paper waste. Integration is the development direction of the printing industry in the future, because printing is transforming from a simple link to a complete production process (including prepress and postpress), and digitization is undoubtedly the leading factor in this transition. Digitization and integration will optimize and automate changes in information such as efficient production planning, automatic machine presetting, and capture of effective production data. As a result, job preparation time and production time are further shortened, and at the same time new highs are ensured in the quality of printed matter and remote services.
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