Introduce several popular new technologies of flexo printing machine
With the improvement of the flexographic printing process, its printing machinery has also developed towards greater operability, improved on-line processing, better printing quality, and higher efficiency of printing presses. The following structures are mainly used in some advanced flexographic printing machines. Paper feed unit: 1. Use of gas inflation shaft. The shaft of the air inflation shaft is equipped with an elastic air cavity. When the air cavity is filled with compressed air, the air cavity will expand, pushing the tension block out, thereby clamping the material winding mandrel. The use of air inflation shaft greatly reduces the steps and difficulty of manual paper change. In the picture, 1-rubber air cavity, 2-pressurizing plate, 3-spring leaf, 4-tightening block, 5/6-clamping block, 7-overflow valve, 8-charging and exhaust hole At present, most of the flexographic printing presses use an air inflation mandrel. The external structure of the air inflation shaft produced by different manufacturers may be different, but the internal principles are the same. 2. High-speed automatic non-stop paper changing device. In wide-format flexo printing machines, in order to improve work efficiency, automatic non-stop paper receiving devices are generally used. Its structure is the same as that of the offset paper roll automatic paper receiving device, and adopts high-speed synchronous surface drive to receive paper. The figure below illustrates how it works. Schematic diagram of high-speed non-stop paper receiving Printing unit: 1. Direct drive without gear motor. Solve the problem that the printing length of the printed matter is limited by the gear pitch, shorten the replacement time of the printing plate and the anilox roller, realize the arbitrary adjustment of the printing length, and enhance the printing flexibility of the machine. At the same time, it not only reduces paper consumption, but also eliminates backlash and runout caused by gear transmission, which improves printing accuracy. 2. Use of sleeve technology. Sleeve technology has the advantages of light weight, small footprint and low transportation cost. These advantages make it easy to replace the sleeve by hand, and it is easy to store and transport. The outstanding advantages of sleeve technology have greatly promoted the rapid development of flexographic printing technology. Sleeve technology is mainly used on plate cylinders. The sleeves that are often used now include plate sleeves and seamless plate sleeves. The plate mounting sleeve is the most common form of plate cylinder, and the photosensitive resin plate is pasted on the surface. Seamless printing plate sleeve The printing plate is in the form of a sleeve, which is directly coated on the printing plate cylinder, reducing the trouble of four-way registration and proofreading when the plate is printed. By using sleeves of different thicknesses, the required printing circumference can also be changed, that is to say, a specification of the outer diameter of the air support roller can meet the needs of different printing circumferences in a wide range by installing sleeves of different thickness , With a high degree of flexibility, such as sleeves with wall thicknesses of 10mm and 70mm, respectively, the difference in printing circumference between the two is nearly 400mm. Fischer & krecke flexo machine with sleeve technology 3. Plate cylinder with detachable structure. Removable plate cylinders are usually used in printing companies that have several different web-flexo printing presses with roughly the same width and different types and lengths of plate cylinder shaft diameters. It is not necessary to equip each printing machine with a complete set of rollers for making a detachable roller shaft for each different printing machine. 4. Closed ink scraper. Compared with the two-roller, forward-scraper and reverse-scraper structure, the biggest advantage of the closed squeegee is the good sealing performance. The reverse squeegee structure in the quantitative ink supply system is suitable for high-speed operation and reduces the solvent. The volatilization and deterioration of the ink solves the foaming problem often encountered in water-based inks. At the same time, the system can also be cleaned automatically, reducing ink replacement time and downtime. The sealed reverse double scraper device consists of an ink chamber (also known as a scraper seat), two pieces of scraper, and an ink type two-stage side sealing plate made of wear-resistant soft material and an anilox roller to form a closed ink chamber. The ink chamber has an ink inlet and an ink outlet. The oil pump sprays the flexographic ink onto the surface of the anilox roller through the ink inlet and stores it in the ink chamber. After inking, the ink is scraped by a scraper, and the scraped ink can continue to be recycled. Increased ink utilization. In the cavity knife system, the two blades have different functions, one is a reverse type, which is a reverse blade, which is used to wipe off the excess ink on the anilox roller; the other is a positive type, which is a positive sealing blade, which plays a sealing role . Closed doctor blade system 5. Drying, solidification and cooling. Modern high-speed flexographic printing presses are equipped with an inter-color drying and drying device, so that the printed products can be fully dried under high-speed printing, and the printing quality is greatly improved. 6. Other auxiliary organizations. Automatically replace the plate cylinder, saving a lot of manpower replacement time. The picture shows the automatic plate loading device equipped with the satellite flexo printing machine. Printing equipment for automatic change of plate cylinder (Fisker Kreik, Germany) In addition to the automatic turning device, there is a mechanical loading cylinder mechanism in the wide-format printing machine. These series of mechanisms have all promoted the development and promotion of flexographic printing. Turning device (Beiren Fuji) Quick change of printing unit design (Nilpete, Denmark) Post-press processing: Configuring a variety of post-press inline processing procedures can not only improve production efficiency, but also save costs. The on-line processing of the printed matter makes the printed matter reduce the handling of the printed matter in the post-print modification and reduces unnecessary damage to the printed matter during the handling process. Online processing can complete multi-color printing, quality control, die cutting, waste removal and paper blank separation at a time without interrupting production, reducing costs in terms of labor, material movement, production process and raw materials. The following figure lists BOBST's inline printing and cutting equipment. BOBST's inline printing and cutting equipment The models below include three types of die-cutting and paper-receiving methods, paper-receiving roll, cut sheet and fan-folding. At the same time, you can also add bronzing, peritoneum, punching, trimming and other institutions, according to different printed products to choose different online equipment to achieve efficient operation. Device for detecting correction and printing observation: Modern flexographic printing presses have incorporated paper tape detection and correction devices. The device has a manual type, and some use sensors. The figure below is a paper feeding tape correction device with a sensor. The mechanism is equipped with a sensor. When the paper tape is offset, the sensor will send a signal to swing the device left and right to realize the paper tape correction. During the entire printing process, an electronic guidance system is generally also configured. The electronic guidance system adopts photodiode or ultrasonic sensor for error detection, and then controls the paper tape by DC motor. In some very advanced machines, there will be an automatic registration device, which can perform all-round automatic registration adjustment. At the same time, in the final rewinding, in order to get a neat material roll, the rewinding device will also be equipped with a correction device. Paper feed correction device Schematic diagram of correcting device structure The printing quality observation device generally includes a stroboscopic, synchronous swing, barrel-shaped rotating mirror observer and video scanning device. They are dynamic observation devices for printed images, which can observe the printed images without stopping the machine, which greatly improves the printing efficiency. The stroboscopic observer uses the controller to adjust the frequency of the flashing of the illumination lamp. When the flash frequency is multiple of the frequency of the printed image passing through the illumination area, the same position of the printed image can be observed to obtain a static printed image. Synchronous swing mirror, as the name implies, is that the swing frequency of the mirror is synchronized with the movement of the printed image, so that the image on the transmitting mirror is always the same area, and dynamic observation of the image is also achieved. The barrel-shaped rotating mirror observer uses a rotating mirror cylinder composed of multiple mirrors to overcome the shortcomings of the above two observation devices to adapt to the printing speed. Delivery unit: Modern flexographic printing machines are generally used for the processing of different printed products such as labels, packaging, or paper products, so their paper delivery devices will also vary from one thing to another. The general mechanism includes a rewinding mechanism for winding the whole roll, a fan-folding mechanism for folding and folding the pressure-sensitive label, a single-sheet cutting mechanism for the roll paper, and a wide-width paper roll that is divided into narrower rolls Paper roll cutting device, etc. Rewinding device, fan-folding device, sheet cutting device module sofas,modern office sofa,office reception sofa Feat Top International(China) CO.,LTD , https://www.ft-project.com