Carton Gravure Preprinting Technology Innovation

The two major exhibitions in 2005, the Shanghai Corrugated Paper Box Exhibition and the Beijing International Printing Technology Exhibition, had pre-printed cardboard boxes. The former displayed a large corrugated paper line with vertical and horizontal holographic identification systems at the Kunshan factory at the Kunshan plant, and announced that the preprinted crepe technology was fully passed; the latter exhibited a wide-format shaftless gravure printing machine for the first time in Shaanxi Beiren. It indicates that paper roll printing is changing with each passing day. From 2002, Tianjin Yannan Packaging purchased the paper gravure printing machine produced by Huayang, Xi’an, and began tentatively preprinting the color of the carton. Today, many dairy, beverage and beer packers in the North have adopted preprinted cartons one after another to illustrate the new preprinting of the carton. Unlimited technological potential.

The domestic packaging industry had a wait-and-see attitude on whether or not preprints could be spread. Experts also debated whether the two kinds of printing processes are better or worse. The Hebei Xianghe Purunxin Printing Co., Ltd., a subsidiary of the Gaoshi Paper Group, concluded from the operation that the gravure preprinted carton surpassed the traditional offset veneer process in terms of quality, efficiency, economy, and return. Beijing Prince Milk Company adopts pre-printing, the unit price is reduced from 1.46 yuan to 1.25 yuan, and the strength is inversely higher than that of offset printing. The company uses 5 million cartons annually and uses pre-printing technology to save 1 million yuan. After two years of costing, the carton factory determined that the compressive strength of the carton and preprinted carton with the same material was 30% higher than that of the offset carton, while the fineness of the printed surface was almost the same as that of offset printing, with a low weight (<200 g = can Completely eliminate flaws.

Prince Milk Pre-printed cartons were printed by Gaoshi Xianghe Printing Factory. Gao's own a total of eight carton printing factories. Purunxin's six-color gravure preprinting machines were imported from Shaanxi Beiren with a width of 1650mm and a machine speed of 120 per minute. In meters, the current month starts to reach 25 classes, and there are 4 million colored boxes provided by Mengniu's 1 litre × 6 single breed each month. Purunxin is the “pre-printing center” of the Gao Group. The web of rolled paper is sent from here to the carton processing plants in different places to meet the needs of modern dairy companies to build factories in different places. It reflects the “centralized printing and decentralization into boxes”. Printing carton production model.

Gravure preprinting has been booming in the North China beverage packaging industry. In addition to Gao's supply of pre-printed cartons to Mengniu through the Hohhot carton plant, Baotou Tiancheng has introduced a Huayang Paper Concave machine to supply 2 million Mengniu boxes per month. Yili, Sanlu, Chengde Lulu and Tsingtao Brewery followed, and the proportion of preprinted cartons increased gradually. Tianjin Yannan, Sanlu Group, Qingdao Jinlong, Beijing Lightlink, Baoding Zhongshida, Fannan Color Industry, Tangshan Sanli, Fujijiali, Chengde Loulu Carton Factory all have their own intaglio preprint production lines. After accumulating the experience of gravure preprinting, Yannan's carton is considering the introduction of a satellite flexographic preprinting machine and locking Xi'an Huayang's Italian partner Flexco (FLEXO) as a machine supplier, indicating that the preprinting in China is broad. The space for survival and development.

Process innovation
The technical process of the gravure pre-printing technology is: paper concave machine multi-color printing roll paper surface → paperboard line webbing → die-cutting machine cutting angle paste box.

The unit type gravure printing machine can complete high-quality, multi-colored color roll paper printing at one time. Since the cycle and cost of gravure production are approaching flexo printing, gravure printers have developed a carton gravure printing machine suitable for China's national conditions, which is more expensive than The satellite flexographic preprinting machine, the lower cost system is very suitable for China's packaging companies. The innovative process of gravure preprinted carton has advantages over traditional color offset printing:

· high productivity. The intaglio printing web has an inking speed of up to 120 meters per minute, which is basically matched with the domestic corrugated board production line. Compared with the flat-sheet offset printing, the invented sheet-fee offset printing method has the advantages of high efficiency, fewer processes, and low cost.

· High quality color effect and can realize ink printing. The gravure ink layer is plump, bright in color, and a full drying system for each color ensures the non-slip resistance of the printed surface. At present, high-temperature gravure pre-printing inks and varnish have been developed in China, and can withstand high temperatures of 180°C and hot plate friction on the hot line of the corrugation line.

· Large-format, multi-color printing. The largest format of traditional color offset printing is generally 1420 x 1200 mm (pan) and up to four colors. The domestic paper concave machine printing format has reached 2500 mm, 6-10 sets of ink glazing roller, and can carry out the special effect color printing of gold ink and silver ink. According to the introduction of Xianghe Purunxin, all Yamaha keyboard enclosures in Asia are using the company's gravure preprint.

· Long printing gives full advantage. The gravure printing roller prints no less than 3 million times, and a single large batch of orders can save time and cost for changeover.

Improve the strength of corrugated boxes. The pre-printing process rolls up and down on the paperboard web and has a certain heating time when forming the corrugated board. It can avoid the pressure damage, uneven glueing, warping of the board and surface reinforcement caused by the offset printing surface. Such phenomena.

· Higher cost performance. The quality of gravure printing products is good, and the strength of the carton is high. Using the same materials, the strength of the preprinted carton is higher than offset printing, so the cost of the carton can be saved by reducing the weight of the cardboard.

System improvement
In the past two years, paper concavers, cardboard lines, and ink manufacturers have made many technological improvements to the misrolling, hot plate dragging, and web breaks that occur in the preprinting process. The new-generation gravure preprinting machine can guarantee that the difference between the inner and outer diameters of the winding is controlled within ±5mm, the temperature resistance of the varnish on the printing surface is up to 220°C, and the error of the large-line transformation installation and vertical cut recognition system is controlled within 1mm.

The technical difficulties that currently plague gravure preprinting are no longer machine equipment but paper. Due to the instability of the moisture content of the domestic gray-white paper, post-printing drying causes the paper to shrink and thus the color registration is inaccurate. Starting from the second color, the difficulty of color registration is more than one color, and the final color registration error will be about 0.5mm. Since lowering the drying temperature does not solve the fundamental problem, it is usually necessary to remake the later colors, especially the final color. In order to avoid returning to the original version, the carton factory has come up with a method to reduce the size of the product in a color-by-color manner, which increases the technical difficulty for the plate-making factory.

From the practical point of view of paper moisture and wide paper strength instability, the most appropriate gravure preprinting machine door width should be set to 1200mm, a narrow range can avoid a series of printing problems caused by paper shrinkage.

The commercial application of the current gravure preprinting is limited to the large-volume beverage packaging industry. The economic volume of the gravure printing carton approved by the carton factory is 300,000, which is lower than the batch customers should pay for the plate making cost. However, it is a common thing to use a box with a large amount of milk in the dairy factory to make 100,000 plates, and at a rate of 0.24 yuan per square centimeter, a plate roller needs at least 800 yuan, and a set of plates cost several thousand dollars. All bear by the carton factory. The only exception is that Xianghe Purunxin produces preprinted cartons for Yamaha keyboards in Japan. Regardless of the quantity, plate-making fees are paid for by customers. Carton manufacturers believe that with the gradual formation of a stable brand image for carton users and the continuous improvement of the supply chain system, gravure preprinting will usher in a new round of development opportunities.

----"Packaging, Printing and Processing"