Talking about the Development of Corrugated Box Flexo Printing Machine

After more than 30 years of research and improvement and strong market demand, corrugated flat sheet presses have made considerable progress. Problems such as unstable feeding, large registration errors, difficulty in tuning, ink scraping and dust, etc. have been greatly improved. The degree of improvement can be analyzed by the following structure of each unit:
(1) Paper-feeding part: The traditional paper-feeding unit is a push-back type. It is often not possible to feed paper due to the bending of the paperboard, and the paper-feeding cannot guarantee the positioning of the paper-board so that the registration error can be set. After the improvement, vacuum adsorption is used to assist the small area of ​​the adsorption plate or the roller. Although the above disadvantages can be improved, the large area of ​​the cardboard may still cause deviation due to the insufficient contact area. French company Martin developed a large-area suction contact vacuum suction belt feeding system for these shortcomings, which can completely solve these problems and ensure the registration accuracy of the leading edge feed.
(2) Paper powder fine removal device: The problem of paper powder confuses the quality of the corrugated brush. The initial method is to remove the brush with the brush and vacuum, but the effect is not obvious. The main reason is that the dust is often electrostatically attached to the cardboard. on. Nowadays, the higher printing quality requirements are all equipped with high-voltage discharge dust devices. First remove the static electricity and then vacuum to improve the dust removal effect.
(3) Cardboard transport: In the traditional printing machine, the paperboard transport between the printing units is carried out by pulling the paper ring. The pull paper ring needs to adjust the position according to the width, and the printed part must be avoided to avoid scratching the ink. In addition, the staged transfer action will affect the accuracy of registration due to the different degree of paperboard bending. BOBST developed the vacuum adsorption transfer system to transport the paperboard by vacuum adsorption and roller. It can suck the paperboard into the machine and stabilize it in the printing unit. There is no periodic beating between the units, which greatly improves the Print registration accuracy, and no need to adjust the position of the draw ring for changing orders.
(4) Printing Ink Supply System: Due to the successful launch of ceramic anilox rollers, flexo printing machines can now be used in addition to traditional rubber ink roller, and can also be used with single-disc scrapers, closed-cell scrapers and other systems. In order to adapt to the different ink line density required for different printing, the flexibility of the printing unit is of utmost importance. Some studies have considered that the printing unit is equipped with a rubber ink guide roller and a closed slotted doctor blade system at the same time. It can also adapt to full-page printing and dot printing with different squeegees. Swiss Bobst company is an electric replacement ceramic anilox roller device. Arranging two to three sets of anilox rollers in each printing unit can be completed in one minute, to adapt to a wider range of printing, printing full version and up to 120L/inch network overprint.
(5) Drying unit: In order to adapt to the increasing trend of carton printing, more and more four-color printing units are currently available. Under this premise, the drying unit is necessary, one can improve the printing quality, and two. Can increase production speed. In addition, during the process of connection, the drying unit can isolate the printing and post-processing (grooving die cutting) process, so as to avoid the dust entering the printing unit and the vibration affects the printing quality. The quantity and configuration of the drying unit depend on the needs and budget. Bobst's models are designed for multi-color printing and in-line lighting, so hot air drying is used after each printing unit, and the last unit is UV-dried to coat UV oil.
The above is only the basic improvement of the corrugated sheetfed printing press, and there are other devices that can be used to improve the printing quality in one step, such as independent motors, ink-monitoring and abnormal line-up devices for each unit. Carton manufacturers should choose the best equipment based on the market's own investment budget. It can be foreseen that the trend of multi-color and high-quality printing of cartons is unavoidable. (Yang Changcai, Martin, France) (From "Paper Packaging")