Discuss high-end napkin printing process

After returning home, he began to pay attention to the production and use of napkins in the country. He found that the towel-type handkerchief had a simple color printing product. Luckily, to Wuhan Green World, he saw the largest napkin production enterprise in China. Mr. Su Xiaohai, the founder of the company, led us to visit the Italian company OMT. Napkin printing machine production of facial tissues. We also saw domestically produced four-color napkin printers. We conducted a large number of investigations and studies in Jiangsu, Zhejiang, Fujian, and Guangdong. We found that most of the napkins produced in China were sold overseas, and only low-end products were used in the country. The scope of use was also limited to facial tissues. . Because of its material structure and the collection of the European and American sample structure, there is a big gap.

Tissue paper is made of two or three layers of non-puckered toilet paper, hinged, printed with a flexographic printing ink, and then formed into a simple combination of a toothed roller and embossed paper foil roller. Such a product can only be used as a handkerchief in Europe. This kind of product is rarely used as a support pad on the table. In the samples of napkins I collected on the European and American tables, I found that the material was micro-sized and compounded before printing. Such napkins are smooth and wrinkle-free with texture and heavy feeling, and a special product is a three-layer structure with a printing layer in the middle. The micro-gel composite product has texture and good flexibility, and the product surface is more beautiful. Some printed materials are not toilet paper but are non-woven fabrics. After detailed comparison, we believe that the current domestic products are only tissues, and are not napkins used abroad.

If the current domestic production of napkins used in the table, you must change the embossing pressure for the micro-compound composite printing before the method, so as to make a qualitative qualitative leap napkin.

Regardless of whether it is used for facial tissue or tabletop napkins, the printing is printed by four-color or five-color flexo printing. However, the printing quality of domestic napkins and facial tissues is affected by the materials. The quality of the napkins and foreign products are still A big gap. The reason is that China's current consumption is still at a relatively low level compared with Europe and the United States. It is impossible for domestic paper manufacturers to use 100% wood pulp to produce. At the same time, manufacturers have to reduce costs and increase the amount of wet strength agent to make our country less available. The raw material paper and foreign raw paper can not meet the requirements of printing on the surface smoothness and wet strength.

Flexo is a method of ink printing. After the paper surface meets water, it is more likely to cause swelling of the paper when the amount of ink is large. Partial unevenness after printing affects the next printing process, and it is also likely to cause wrinkles. At the same time, the easily swellable printing material is exacerbated. The fluctuation of tension makes the accuracy of overprinting more fluctuating. It is difficult to produce good products. Because of the poor wet strength of toilet paper, loose fibers on the paper are easily brought onto the plate after contact with the printing plate, resulting in a paste platen to prevent continuous printing, which seriously affects printing quality and yield. .

At present, domestically-imported equipment and domestically produced equipment are basically four-color continuous printing and then uniformly dried and embossed and folded. Therefore, it is difficult to ensure product quality.

For various comparative studies, Xi'an Black Bull Machinery Co., Ltd. has developed a CRY460 napkin printing machine suitable for China's national conditions, which basically solves many problems in the printing process.

Napkin printing materials are very flexible and can not be unwound and unwinding. Domestic and foreign equipments are driven and unwound on the surface of the belt by unwinding. In order to ensure the printing precision and folding accuracy under normal tension, it can adapt to the changes of different materials and printing ink, All levels adjust a certain proportion of the long-lead rate, pure mechanical adjustment of the belt uncoiling will produce proportional fluctuations and cumulative errors, resulting in poor registration accuracy, printing is difficult. The unwinding of CRY460 napkin printing machine manually adjusts and unwinds the mechanical transmission, changes the design to AC servo drive unwinding, uses the low-friction cylinder to accurately detect the tension, and closes the loop to control the speed differential driving mode. This firstly provides a reliable guarantee for pre-press tension control. . After long-term operation, the registration accuracy is ≤±0.5mm; the folding accuracy is ≤±1mm; stable and continuous production is achieved.

CRY460 Napkin Press has changed the traditional method of printing four-color centralized drying, adding an oven in each color group, so that the swelling of the napkin ink after ink is removed after each color is printed without affecting the next color group, so that the guarantee Flat and wrinkle-free, so that the printing quality is greatly improved, and the amount of ink per color group is more stable and accurate, and the service life is long. In order to eliminate the steel gravure ink transfer method, a finer and more accurate ceramic wire roller is used for finer transmission. Screen printing provides protection.

CRY460 has added a micro-coating device to the special design of the rolling stage after uncoiling. This device can apply the anti-sticking solvent to the surface of the printing substrate while rolling and rolling, so that the fine loose fibers on the raw material will not stick. Paste on the printing plate surface, this greatly improves the printing duration, reduces the number of cleaning plates, improves the plate life, and improves the yield.

According to the characteristics of Italian OMT folding mechanism and domestic folding mechanism, a new type of folding mechanism has been carefully designed, which has significantly improved the folding speed and accuracy.

Xi'an Black Bull Machinery Co., Ltd. has begun research on micro-sized sizing equipment for toilet paper. The micro-size sizing composite printing material has a smooth and wrinkle-free appearance and increases the feeling of cotton cloth. Fine-printed products can be compared with European and American products. . We are willing to cooperate sincerely with our colleagues in the industry to conduct technical discussions and exchanges so that the napkin printing industry can quickly catch up to foreign standards.

Author: Black Cattle Xian Machinery Co., Ltd. Li Yulong
Reprinted from: Guangdong Packaging