Comparison of offset printing and flexo printing in the carton field

(offset v flexo -big time shoot out) In recent years, sleeve technology has given flexographic printing a boost to the development of the flexographic printing industry, which has taken a lot of market share in offset printing, especially in the folding carton market. Therefore, The competition between these two different printing technologies has intensified. Is it now that it is the turn of the offset printing? In fact, for a long time, the controversy surrounding these two kinds of crafts has always been one of the hot topics in the industry, and many people have exaggerated or denounced one of them in a one-sided manner. In fact, we should analyze and weigh the advantages and disadvantages of each printing process for a specific application area, and make a fair and appropriate evaluation based on it. Today, we use carton packaging printing as an example to compare the advantages and disadvantages of these two printing processes. Although the competition between the two processes is very fierce, it has not brought about much development to the printing companies. Fortunately, this situation has turned a corner and many relevant articles have now been published. BASF is a Swiss manufacturer of inks, plates, and consumables. It has conducted in-depth research specifically to determine which of the two printing processes, offset printing and flexo printing, is more suitable for printing high-grade paper. Box packaging. Through the analysis of the research results, BASF has made great contributions to both processes, and brought a fresh breath to our analysis and debate. As long as you carefully pay attention to the details and conduct a thorough analysis, you can ensure that the results obtained are fair and impartial, and each craft does not have to be bound to a certain range of standards. In this study, the selected substrate material was Stora Enso's 240 g/m2 printing paperboard. The printed job was a biscuit box. In addition to the four-color image, the job also contained a Spot color is used to print the blue trademark of the biscuit manufacturer. The job is printed using two processes, offset printing and flexo printing. The offset press uses a Heideberg 72 Heidelberg five-color machine. It also cooperates with a flexo printer to perform on-line lighting. The number of prints is 6,000, and the printing speed is 9000 inches/hour. In flexo printing, two inks and two types of machinery were used: one was water-based UV-curing ink, the printing machine was printed on a Lemanic 82F, the printing speed was 120 meters per minute, and a total of 5,000 meters was printed; Solvent-based UV ink, printing machine Bobst Lemanic 62 F, printing speed 115 m/min, total printing 6000 m. Through experiments, you will quickly find that there is a big difference between the two processes. Separation data cannot be shared at all or simply exchanged. That is, existing offset printing or offset printing points The color data is not suitable for flexographic printing and cannot be directly used in flexo printing. It is necessary to adjust and modify the flexographic printing process accordingly. In color separation, if a halftone image is placed on the same plate with a solid color patch of the same color, the halftone image portion generally adopts a higher resolution, and the required amount of ink is less, and the solid portion requires. The amount of ink is relatively high, so there is a certain contradiction between the two. Can fish and bear's paw have both? This is perfectly possible in offset printing, and we do indeed do this in actual production. It is entirely possible to ensure that the solid areas are well inked and uniform, while fine-tone halftone images are also reproduced better. However, in flexographic printing, there is no guarantee of the balance between the two, and only one of them can be satisfied. In this way, the biscuit box only needs to be divided into five colors (four primary colors, plus a blue spot color) for offset printing and printing. However, seven copies are required for flexo printing. To print. This is only basic, common-sense knowledge in the flexo printing process, but is it good or bad to divide into seven color plates? People are stubborn about this and are mixed. When printing with seven colors, the advantage is that the dark tone portion and the tone effect are excellent, especially for the control of the important halftone image to be obviously better than offset printing. Similarly, seven-color printing also has some disadvantages: due to the addition of two additional colors, the color needed to be controlled is also greater, the workload is large, and the error rate is even higher, especially for global well-known brand product packaging. This cannot be ignored. A skilled and skilled printer of a person pays more attention to the favorable side, and is less susceptible to adverse factors. From this point of view, the quality and skill requirements of production personnel in flexo printing are higher than that of offset printing. In addition, the number of screens used in both offset and flexo printing processes is not the same. The number of offset printing screens can easily reach about 150 lpi, while the number of screens for flexographic printing can only reach about 137 lpi. In the replication process, the flexographic printing needs more consideration than the offset printing. The hardness of the plate, the type of the adhesive, and whether the plate is a sleeve or a CTP are all factors. If one of these factors changes, the final printed image will almost always change. The choice of anilox roller will play a decisive role in the quality of the final image. In general, the number of anilox roller lines required to print a halftone image is 4-5 times the number of screen printing lines. In flexographic printing, the printing pressure must be increased. It is not difficult to form a 1% dot in the printing plate. However, it is difficult to make the 1% dot on the flexographic printing press completely preserved and transferred to the printing material. This is a big challenge for flexographic printing companies. This is the reason for reducing the number of screens. Even when printing the solid area, the printing plate should be properly screened (for example, 1% of the small negative screen), so that the transfer of ink is more complete and the resulting solid part is smoother. In fact, for skilled flexo printing operators, these are not really special challenges. However, the emphasis here is on skills. Operators must master these skills. Therefore, this is for those who enter the flexo printing industry. But for companies and individuals who want to print high-end cartons, this poses some obstacles. Now that everyone is OK, everyone does not have to worry about it. With the BASF system, each printer can become a master, and the quality of the printed matter is also good. With the help of a microscope, the quality of the printed matter can be checked. The result of the inspection with a microscope was surprising. The quality of the offset printing was higher, and the lines and dots of the water-based flexo were not very complete, but the degree was not too great. The fine lines produced by both sheetfed offset and solvent-based flexo are very clear and look almost exactly the same, which means that in terms of dot gain, the two processes are almost identical. identical. This is especially important when evaluating the print quality of bar codes. Although the print quality of bar codes does not have much to do with the sale of products, it plays an important role in the success of packaging. Through experiments, it can be clearly seen that not every flexo printer can print the high-end carton very smoothly and smoothly as an offset printer. In addition, it is required that the flexographic printing press must be the highest standard, and almost all adopt the direct imaging technology of the CTP sleeve. If these conditions are all available, the flexographic printing process is still very competitive. However, only the ultimate consumer's personal views and opinions on the product are the reasons that really drive him (her) to choose and buy the product, rather than the question of which printing process has a competitive advantage. We put all kinds of printed paper boxes on the shelves of supermarkets, and let a group of testers who do not understand printing choose the boxes. Of the three cartons, 53% of the testers chose solvent-based UV flexo cartridges, which accounted for an absolute advantage, and those who chose the UV water-based flexo and offset cartons were exactly 23.5 each. %. Of the testers who chose a solvent-based UV flexo cassette, 73% considered the carton to have a high gloss and looked beautiful, so this box was chosen. In addition, most testers also believe that the UV flexo-printed carton has a nearly three-dimensional effect, while the offset carton does not have this effect.