Application status of wide width satellite flexogr

Application status of wide satellite flexographic printing press

satellite flexographic printing press is a public printing press with embossing drum, that is, there is only one embossing drum

after years of production practice, flexographic printing has formed a basic positioning in China's packaging printing market. The range and types of prints are increasing, and the market share of flexo printing is gradually expanding. Trademark labels, plastic flexible packaging, woven bags, folding cartons and web paper are the main products of flexographic printing in the packaging and printing market

in unit type, laminated type and satellite type flexographic printing, unit type and satellite type are the two most important models. Compared with the unit type, the satellite flexo printing machine has higher overprint accuracy. Because the material belt is tightly wrapped on the central embossing drum, the tension is very stable and there is no need for automatic registration control system; Simple structure, short distance between embossing points, convenient for registration quality; And the machine has good structural rigidity and more stable performance. In the European and American markets, satellite flexographic machines account for about 70% of the whole flexographic machine market, and most of them are used in flexible packaging printing, corrugated pre printing and label printing. At present, there are only a dozen satellite flexographic machines imported from abroad. The application of wide width satellite flexographic press in China's printing field is mainly concentrated in three aspects: first, carton pre printing; Second, flexible packaging printing; Third, newspaper printing

I. application of satellite flexo printing machine in carton preprint

in the case of mass production, flexo preprint has the following unique advantages:

1 Fast printing speed and high production efficiency. The printing speed can reach 300m/min, and the printing speed with UV ink can reach 500m/min-600m/min. in addition, it is equipped with a rapid roll change system to automatically receive materials without stopping, so as to achieve complete uninterrupted printing

2. Pre printed cartons are overprinted accurately, resulting in small color difference and high printing quality. Because the high-precision satellite flexographic press has uniform printing pressure and is not affected by the height of corrugated, the printing quality of field, line and text is very good. The vector variable frequency motor can be used to realize synchronous control through PLC controller to ensure the constant tension of printed products at different speeds and temperatures, so as to maintain the stability of overprint in high-speed printing and accurately realize the multi-color overprint of carton preprint. Less lateral shrinkage of paper

3. The closed doctor blade system can ensure the optimal ink volume of the roller and printing plate, improve the ink transfer function of the short ink path system, reduce solvent volatilization and make the ink color consistent

4. The carton has high strength and good flatness. After roll to roll printing, the printed color roll can be directly placed in the vermicelli station and bonded with corrugated to form Durethan nylon 6, which can replace the cardboard used by nylon 66 on the engine oil pan and be directly made into a single carton through the computer cross cutting machine, giving full play to the printing 4. There is no corrosive medium around; The automatic and high-speed advantages of brushing machine and corrugating machine make the corrugation free from printing and deformation, and the strength of carton can be increased by 30%, which can reduce the gram of paper and reduce the cost of corrugated carton

5. Because the printing plate is flexible, the requirements for the surface finish of the paper are not as strict as those of gravure printing, which can reduce the paper cost and reduce the cost of corrugated box

II. Application of satellite flexo printing machine in flexible packaging printing

at present, the flexible packaging products printed by satellite flexo printing machine in China are mainly concentrated in roof bag, Tetra Pak bag and film. For example, Shanghai International Paper and Shandong Quanlin paper have introduced medium width and wide width satellite flexographic machines from Germany for the printing of folding cartons such as roof bags and Tetra Pak bags respectively, while Hainan modern color printing introduced flexographic machines from Germany for the printing of plastic bags

the use of satellite Flexo machine printing flexible packaging products has the following advantages: 1 The use of soft polymer resin plate shortens the plate making cycle compared with gravure printing. Due to the improvement of plate manufacturing level and plate making technology, the wrinkle roller can reach the level of 175 lines, which is enough to meet the needs of general packaging printing; 2. The roller is used to transfer ink. The roller is both an ink transfer roller and an ink metering roller, which realizes the same short ink path as gravure printing, and can accurately supply ink according to the process requirements. At present, the cermet roller with laser engraving can reach the level of 1600 lines, which provides a favorable means for accurately controlling the ink color and ink layer thickness; 3. Zero pressure printing not only reduces the vibration and wear of machinery, but also reduces the wear of plates, which is especially conducive to the printing of soft materials. The power system is equipped with anti vibration and damping devices. During transmission, it is transmitted through the synchronous belt of the main motor, which greatly reduces the vibration and noise of the machine operation; 4. Use water-based environmental protection ink to reduce pollution; 5. Because the material belt is tightly wrapped on the central embossing drum, the tension is very stable, and materials with large scalability, such as PE film, can be printed to make up for the deficiency of the combined gravure press

III. satellite flexographic press has certain development potential in the field of newspaper printing

the advantages of flexographic newspaper printing can be summarized as follows: 1 The ink level is clear, and the printing color is bright; 2. Due to the water-based ink printing, the paper is almost dry, the readers' fingers will not be stained, and the tablecloth on the dining table will not be dirty; 3. It is economically advantageous to use flexographic printing to print color newspapers. The paper loss is less and the gram weight of paper will be further reduced; 4. The operation is simpler than offset printing. According to relevant information, the proportion of European and American countries in printing newspapers with satellite flexographic press has reached 38%. In China, the media industry is also a sunrise industry in the 21st century. I believe that with the vigorous development of this industry, flexo printing will also occupy a certain market share

the printing products suitable for the wide width satellite flexo printing machine include playing cards, banknotes, napkins, toothpaste and cosmetic hoses, etc. because the printing plate is flexible, the requirements for the surface finish of printing materials are not as strict as those for gravure printing, and woven bags, kraft paper and other materials that are difficult to be gravure printed can be printed

the technology of satellite flexo printing machine has been quite mature abroad, but it is still in its infancy in China. The specific shortcomings are as follows:

1 Technological limitations

at this stage, flexographic printing has insurmountable defects compared with offset printing and gravure printing: the ink transfer mode is limited by the number of lines of the roller, the adjustment is complex and is not easy to be compatible. Therefore, the line level part and the field line part are often separated for plate making, which increases the cost. Due to the great elasticity and softness of flexographic plate, it is easy to deform after compression, resulting in poor ability to restore the original. The fineness of flexographic printing is 136 lines/inch or 150 lines/inch, while offset printing and gravure printing are familiar with 175 lines/inch printing, and the restoration of the original is excellent. In addition, in some color gradients or absolute places, flexo printing also has insurmountable defects

2. Packaging design does not adapt

the differences between oriental culture and European and American culture make their packaging design styles significantly different, which also affects the development of flexo printing in China in the short term. Europe and the United States emphasize the use of concise color blocks. Lines have a strong visual impact on people, and China's packaging industry has been affected by gravure and offset printing for a long time, focusing on realism and using a large number of realistic hierarchical patterns. To use flexographic printing to catch up with the printing quality of offset printing and gravure printing, it is bound to be difficult for end users to accept. Therefore, flexographic printing is less accepted in China than offset printing and gravure printing

3. Cost gap

because gravure printing and offset printing have experienced more than 20 years of development in China, and the equipment and materials have been localized, both the equipment investment cost and the cost of plate making and post-processing have decreased greatly. High quality flexographic printing machines, plates, plate making equipment and materials need to be imported, so the cost is basically the same as that in Europe and America. However, the cost of offset printing and gravure printing in Europe and America is higher than that of flexo printing, which is also the reason why flexo printing develops so fast in Europe and America. The cost of gravure and offset printing in China is lower than that of flexo printing, so the price competitiveness of flexo printing in China's packaging market is very weak

4. Use gap

People's understanding of packaging printing still stays in gravure and offset printing, and the acceptance of flexo printing in the packaging market is not high. Flexo printing uses water-soluble ink, which is conducive to environmental protection, especially in food, beverage and other packaging. However, gravure printing has also widely used ink and alcohol soluble ink. In addition, China's attention to environmental protection is relatively low at this stage, and the final customer requires that the cost be reduced again and again, so the selling point of environmental protection is also weak

5. Flexographic plate making cost is not dominant compared with offset printing and gravure printing

flexographic plate making cost is several times higher than offset printing, which is almost the same as gravure printing. The reason is that the prepress equipment, plate making equipment and raw materials for producing high-quality flexographic plates need to be imported, and its core technology has not been mastered in China. At present, domestic high-quality plate manufacturers mainly include: Dalian Fulai plate making company, Shanghai Dongyang laser plate making company and Shanghai Renshi computer plate making company. In the near future, the plate making cost is unlikely to have a large room for decline

6. Flexographic printing process has not been well mastered

for most printing plants, they are familiar with offset printing and gravure printing process, but they are new and unfamiliar with flexible process. If the flexo printing process is introduced, the internal structure and management of the factory should be changed and adjusted accordingly. No matter how good the printing plate quality is, if the flexographic printing process can not keep up, it can not fully reflect the intention of the original design and meet the requirements of users. Printing technology is a comprehensive technology. The common faults of flexographic printing include poor inking, dry plate pasting, edge defects, improper pressure, pattern deformation, dimensional displacement, ink rod and so on

in order to solve this kind of problems, in addition to the factors of equipment and materials, the printing process must also be solved. Such as roller matching, pressure between roller and printing plate, pressure between printing plate and embossing cylinder, variable relationship between ink viscosity and machine speed, etc. Without a set of data and operating procedures, it is difficult to print good products. At present, flexographic printing industry should not only have its own printing experts, but also plate making experts and water-based ink experts. Due to the application of computer technology, the requirements for plate making and printing technology are more strict, and there will be more demand for high-quality flexographic printing talents

7. Flexographic plate making technology

flexographic plate is an organic synthetic colloid, which uses light irradiation to harden the colloid when exposed to light. At present, countries all over the world produce several kinds of photosensitive resin plates, which are divided into two categories: base materials and non base materials. There is no need to expose the back of the base material. The thickness of the plate is about 0.95mm. After the front is exposed, wash and dry it with water. The thickness of substrate free printing plate material is 1.7mm, 2.28mm, 3.94mm and 7mm respectively. The back exposure shall be carried out first, and then the front exposure. The front and back exposure time can be completed in sequence after setting once; The length is determined according to the pattern level and climate change. The development performance after photosensitization is excellent. The non photosensitive part can be washed and removed with chemical solvent, and then removed and dried. A printing plate can be completed in only 2 hours

at present, the color original design and four-color dot production of flexographic printing in China are still a weak link. The key problems need to be studied hard, learn from the relevant process and technical experience of other printing methods, and combine the characteristics of flexographic printing to find out a set of process technology, quality control and detection means for making flexographic plate,digital display testing machine
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