Discussion on the printing technology of the most

Discussion on the printing process of high-grade napkins

I visited the four-year "drupa" printing machinery exhibition in Dusseldorf in 2003, and came into contact with the napkin printing and folding machine. At the same time, after visiting Germany, I visited several Italian cities. For ten days abroad, I paid attention to the napkins used for three meals a day, and paid attention to the collection of each meal. I wanted to see the European consumption concept, which will gradually affect the Chinese people. Once the table culture in China with a population of 1.3 billion changes, the use of napkins will bring huge business opportunities

after returning to China, we began to pay attention to the production and use of napkins in China. We found that there were simple color printing products for handkerchiefs, and we were more fortunate to see the largest napkin production enterprise in China in Wuhan green world. Mr. Su Xiaohai, the founder of the enterprise, led us to visit the production of napkin paper of OMT napkin printing machine in Italy. We have also seen domestic four-color napkin printing machines. We have done a lot of research in Jiangsu, Zhejiang, Fujian and Guangdong, and found that most of the napkins produced domestically are sold overseas, and only low-grade products are used domestically, and the scope of use is also limited to facial towels. Because its material structure is quite different from that of European and American samples I collected

facial tissue paper is a simple combination of two or three layers of wrinkle free toilet paper passing through the hinge, printing with flexographic ink, and then embossing with a toothed roller and a paper foil roller. Such a product can only be used as a handkerchief. In Europe, this product is rarely used as a cushion on the table. In the napkin samples collected by me on European and American tables, I found that the materials were micro sized and compounded before printing. Such napkins are flat and wrinkle free, with texture and massiness. A special product is the three-layer structure with the printing layer in the middle. The micro glue composite product has texture and good flexibility, and the product surface is more beautiful. Some printing materials are not toilet paper but non-woven fabrics. After detailed comparison, we believe that the current domestic products are only facial napkins, not napkins used abroad

if we want to produce napkins for dinner tables in China at present, we must change the method of embossing and pressing into micro sizing and then printing, so as to make a qualitative leap in the quality of napkins

no matter the face napkin or the bedding napkin used on the table, its printing adopts the method of flexo printing, four-color or five color printing, and then folding and forming. However, the printing quality of domestic napkins and face napkins is affected by materials, and their product quality is still far from that of foreign products. The reason is that China's current consumption is still at a relatively low level compared with that of Europe and the United States. Domestic base paper manufacturers cannot use 100% wood pulp for production. At the same time, in order to reduce costs, manufacturers add less wet strength agent, so that the surface smoothness and wet strength of China's raw paper and foreign raw paper can not meet the requirements of printing

flexo printing is a water ink printing method. When the paper surface meets water, especially when the ink volume is large, it is more likely to cause the swelling of the paper. After printing, the local unevenness affects the next printing, and it is also easy to cause wrinkles. At the same time, the swelling printing material intensifies the fluctuation of tension, making the overprint accuracy fluctuate greatly. It is difficult to produce good products. Due to the poor wet strength of toilet paper, it is easy to bring the loose fibers on the paper to the printing plate after contacting with the printing plate, resulting in paste, which makes the printing unable to proceed continuously, and more seriously affects the printing quality and yield

at present, both domestic and imported equipment are basically the process of embossing and folding after four-color continuous printing, so it is difficult to ensure the product quality

for various comparative studies, Xi'an Heiniu Machinery Co., Ltd. developed a cry460 napkin printing machine suitable for China's national conditions, which basically solved many problems in the printing process

napkin printing materials are very elastic and cannot be pulled to uncoil. Equipment at home and abroad use belt surface to drive uncoiling on uncoiling. In order to ensure the printing registration accuracy and folding accuracy under normal tension, and adapt to the changes of different materials and ink volume, a certain proportion of the elongation rate is adjusted at all levels. The belt uncoiling adjusted by pure machinery will produce proportional fluctuations and cumulative errors, resulting in poor registration accuracy and difficult printing. The uncoiling of the cry460 napkin printing machine manually adjusts the mechanical drive to uncoil, and changes the design to an AC servo driven uncoiling mode, which uses a low friction cylinder to accurately detect the tension, and closed-loop control the speed difference. This first provides a reliable guarantee for prepress tension control. After long-term operation, the registration accuracy is ≤± 0.5mm; Folding accuracy ≤± 1mm; The stable and sustainable property structure and further optimized production have been realized

cry460 napkin printer changes the traditional four-color centralized drying method after printing, and adds an oven in each color group, so that the swelling of napkin ink after printing is eliminated after each color printing without affecting the next color group, so as to ensure smoothness and wrinkle free, greatly improve the printing quality, and the ink transfer volume of each color group is more stable and accurate, with long service life, and eliminate the steel gravure ink transfer method, The use of ink transfer is the main research object during the birth and development of high molecular chemistry. Fine and accurate ceramic rollers provide a guarantee for fine picture printing

cry460 special design of the rolling level after uncoiling. The main feature of the first dentalmodel is high precision. A micro coating device is added, which can apply the anti paste solvent on the surface of the printing substrate while rolling, so that the fine and loose fibers on the raw materials will not stick on the printing plate, which greatly improves the printing duration, reduces the times of cleaning the plate, and improves the service life of the printing plate, Improved yield

according to the characteristics of OMT folding mechanism in Italy and domestic folding mechanism, a new type of folding is carefully designed and deburred with sandpaper and oilstone mill; If the rising position exceeds the limit and the tilting mechanism, the folding speed and accuracy have been significantly improved

Xi'an Heiniu Machinery Co., Ltd. has begun to study the micro sizing compound equipment of toilet paper. The printing materials with micro sizing compound are flat and wrinkle free, and increase the cotton sense. Only after fine printing can the products be compared with European and American products. We are willing to sincerely cooperate with colleagues in the industry to carry out technical discussion and exchange, so that the napkin printing field can quickly catch up with the foreign level

source: Guangdong packaging

Author: Li Yulong, Xi'an Heiniu Machinery Co., Ltd