The domestic packaging industry has been holding a wait-and-see attitude on whether pre-printing can be spread. Experts also debated the advantages and disadvantages of the two printing processes. Hebei Xianghe Purunxin Printing Co., Ltd., a subsidiary of Gaoshi Paper Group, concluded from the business argument that the gravure pre-printed carton surpassed the traditional offset veneering process in terms of quality, efficiency, economy and return. Beijing Taizi Milk Company adopted pre-printing, and the unit price was reduced from 1.46 yuan to 1.25 yuan, and the strength was inversely improved compared with offset printing. The company's annual consumption of 5 million cardboard boxes, using pre-print technology to save 1 million yuan. After two years of cost accounting, the carton factory has the same paper-loading material, the compressive strength of the pre-printed carton exceeds 30% of the offset printing carton, and the print surface is almost the same as the offset printing, and the low-weight paper (<200 g = can Thoroughly eliminate penetration defects.
The Prince's milk pre-printed carton is printed by Gaoshi Xianghe Printing Factory. There are eight carton printing and processing factories in Gaoshi. The six-color gravure preprinting machine of Purunxin is imported from Shaanxi people. The width is 1650mm and the machine speed is 120 per minute. M, currently starting 25 classes in the month, there are 4 million color boxes provided for Mengniu 1 liter × 6 single items each month. Purunxin is the “pre-printing center†of Gaoshi Group. The roll paper is sent from here to the carton processing factories in various places to meet the needs of modern dairy companies to build factories in different places, reflecting the pre-production of “concentrated printing and dispersing into boxesâ€. Printing carton production mode.
Gravure pre-printing has been booming in the beverage packaging industry in the north. In addition to Gao's supply of pre-printed cartons to Mengniu through Hohhot Carton Factory, Baotou Tiancheng introduced a Huayang paper diverter to supply 2 million Mengniu boxes per month. Yili, Sanlu, Chengde Lulu and Tsingtao Beer followed closely, and the proportion of pre-printed cartons increased gradually. Tianjin Yannan, Sanlu Group, Qingdao Jinlong, Beijing Lightlink, Baoding Zhongshida, Fannan Caiye, Tangshan Sanli, Fujijiali, Chengde Lulu Carton Factory all have their own gravure pre-printing production line. After accumulating gravure preprinting experience, Yannan Carton is considering the introduction of a satellite flexo preprinter to lock up the Italian partner Flexco of Xi'an Huayang as a machine supplier, indicating that preprinting has a broad presence in China. The space for survival and development.
Process innovation
The process of gravure pre-printing technology is: paper multi-color printing reel paper paper → cardboard wire → → → die cutting machine chamfer paste box.
The unit type gravure printing machine can complete high-quality, multi-color color roll paper printing at one time. Due to the current cycle and cost of gravure production, the gravure printer has developed a carton gravure preprinter suitable for China's national conditions. The satellite flexo preprinting machine, the lower cost system is very suitable for China's packaging enterprises. The innovative process of gravure pre-printed cartons has advantages over traditional color offset printing:
· high productivity. The printing speed of gravure printing web is up to 120 meters per minute, which is basically matched with the domestic corrugated board production line. Compared with the flat sheet paper offset printing method, it has the advantages of high efficiency, less process and low cost.
· High-quality color effects and ink printing. The gravure ink layer is full and the color is bright. The sufficient drying system after each color printing ensures the anti-slip and anti-friction properties of the printing surface. At present, high-temperature gravure pre-printed inks and varnishes have been developed in China, which can withstand the high temperature of 180 °C and hot plate friction at the hot end of the corrugated wire.
· Large format multi-color printing. The maximum format of traditional color offset printing is generally 1420 × 1200 mm (large sheet), up to four colors. The printing width of the domestic paper concave machine has reached 2500 mm, and the ink glazing roller has 6~10 sets, and can print the special effect color of gold ink and silver ink. According to Xianghe Purunxin, all Yamaha keyboard covers in Asia are pre-printed with the company's gravure.
· Long prints have an advantage. The gravure printing plate has a printing durability of not less than 3 million times, and a single large order can save the plate changing time and standby cost.
· Improve the strength of corrugated boxes. The pre-printing process rolls up the roll on the cardboard line, and the corrugated board has a certain heating time during molding, which can avoid the crushing and unevenness of the offset on the offset of the offset printing, the warpage of the cardboard and the ribbing of the surface layer. And so on.
· Higher cost performance. The quality of the gravure printing is good, the strength of the carton is high, and the same material is used. The strength of the pre-printed carton is higher than that of the offset printing, so the cost of the carton can be saved by reducing the weight of the cardboard.
System improvement
Over the past two years, paper recessors, paperboard and ink manufacturers have made many technical improvements to the pre-printing process, such as shrinking, hot-plate drag and paper breaks. The new generation of gravure pre-printing machine can ensure that the inner and outer ring diameter difference of the winding is controlled within ±5mm, the protection temperature resistance of varnish to the printing surface reaches 220°C, and the error of the vertical and horizontal cutting identification system of the large-line transformation installation is controlled within 1mm.
The technical difficulty that currently plagues gravure preprinting is no longer machine equipment, but paper. Due to the unstable moisture content of the domestic gray-based white paper, the post-press drying causes the paper to shrink and the color registration is inaccurate. Starting from the second color, the color of one color is larger than one color, and the color deviation of the last color will be about 0.5mm. Since lowering the drying temperature does not solve the fundamental problem, it is usually necessary to re-plate the next few colors, especially the final color. In order to avoid returning to the plate, the carton factory has come up with a way to reduce the size by color, which adds a lot of technical difficulty to the plate making factory.
From the practical point of paper moisture and wide sheet paper instability, the most suitable gravure preprinter door width should be set to 1200mm, the narrow frame can avoid a series of printing problems caused by paper shrinkage.
The current commercial application of gravure preprinting is limited to the bulk beverage packaging industry. The economical batch of gravure cartons approved by the carton factory is 300,000, which is lower than the volume customer. However, it is also common to use 100,000 pieces of dairy factory cartons with a large amount of boxes. It is common for 0.24 yuan per square centimeter. A plate roll needs at least 800 yuan, and a set of thousands of dollars. All are undertaken by the carton factory. The only exception is that Xianghe Purunxin produces pre-printed cartons for Japanese Yamaha keyboards. No matter how many, the plate-making fees are paid for customers. Carton manufacturers believe that as carton users gradually form a stable brand image and the supply chain system is improving day by day, gravure pre-printing will usher in a new round of development opportunities.