Gravure Printing Carton Preprinting Innovative Process Applications (1)

The preprinting of gravure printing carton is to pre-print the corrugated carton on the wide web (carton paper) with the required fine pattern before making the corrugated cardboard, and then printing the good paper in roll shape. The upper corrugated board production line is made of corrugated boxboard, and then die-cut by a die-cutting machine into a box type.

At present, 30% of the total output of corrugated boxes in some developed countries such as Europe and the United States adopts preprinted new technologies. With the rapid development of China's paper product packaging industry, many customers have stable cartons such as Mengniu, Budweiser and Qingdao in recent years. Beer, etc. have turned their eyes to new pre-printing technologies. With the packaging and packaging of beverages, beer, home appliances and foodstuffs in the design and usage of corrugated boxes, the use of web pre-printing to produce high-grade colored corrugated boxes will become a future package. Industry development trend.

● Web preprinting is better than flat offset preprinting

At present, the vast majority of domestic color cartons use flat sheet offset printing preprinting methods. The process flow is: cutting webs into single sheets, offset printing, single sheet printing, and single-sided roll-rolling. Paperboard → Face Paper and Single-faced Corrugated Paperboards are pasted on veneer or veneer veneer → die-cutting indentation forming → nail box/adhesive box.

The technological process of the web gravure printing preprinting technology is: gravure printing machine printing surface layer paper roll → cardboard line production cut into three (or five) cardboard → die-cutting indentation molding → nail box/glue box.

So why do you need gravure preprinting? There are two main reasons. First, gravure printing can easily provide high-quality color prints. Second, electronic engraving technology can significantly reduce the production cycle and cost of metal plate rollers, which is close to or even lower than that of flexographic plates. Moreover, the domestic Shaanxi Beiren has produced a high-speed wide-format paper concave machine, the price is only one-third of the imported flexographic printing press, and the gravure pre-printing method may be more suitable for the actual situation of packaging companies in China.

In comparison, people often refer to the commonly used printing process as “post-printing”. Pre-printing has some obvious advantages over post-printing:

- Get higher print quality and adaptability. The pre-printing is performed on a smooth paper surface using a gravure printing machine or a flexographic printing plate. Compared with the printing after printing using a printing slotting machine to print on uneven paperboard surfaces, it is possible to perform fine color printing with richer layers and brighter colors. Printing quality will also be more stable and reliable.

- The highest strength of corrugated board can be achieved, because the pre-printing does not need to imprint the board after it is formed, thus avoiding the deformation of the corrugated board and weakening of the board strength. After printing with corrugated board printing slot machine, each color printing will cause more or less deformation of corrugated board, and the more color number, the greater the effect on the deformation of corrugated board.

- High production efficiency, ease of production management, low scrap rate, etc. Preprinting has become an important trend in the printing of corrugated board, especially the printing of high-grade cartons (including large and special-shaped cartons).
The use of intaglio printing carton preprinting has the following salient features compared to traditional color offset printing:

--high productivity. Gravure printing web printing speeds up to 150-200 m/min, basically matching many corrugated board production lines in China, shorter than traditional flat-sheet offset printing and veneer lapping, low labor cost and high efficiency.

- Color carton produced by gravure pre-printing can get high-quality ink prints. Due to the high accuracy of gravure printing, it is not more than 0.2mm. Gravure printing can also finish printing and varnishing once. General gravure printed wire after printing Up to 300 lines, gravure printing ink than other printing methods, up to 4.5-6g/m2, India ink full, soft, bright, solid, and gravure printing after each color has a full drying system, Therefore, under the premise of choosing the paper with higher surface smoothness for printing, gravure printing can obtain high printing quality of ink and ink. Most cigarette packs are made from paper gravure printing. At present, the domestic production of paper gravure printing inks has been relatively mature, domestic has been able to meet the corrugated board line preprinted with water-based paper gravure ink, can fully meet the corrugated board production line 180 °C high temperature and hot plate friction.

- Large-format, multi-color printing is possible. The maximum size of traditional color offset printing is generally up to 1.2m×0.9m (encyclopedia), and most of them are four-color printing. The maximum printing material width of the gravure printing machine for carton preprinting is 2.5 meters (Shaanxi Beiren Printing Machine Co., Ltd.) At present, it has produced a variety of preprinting machines, including 1300mm, 1650mm, 1800mm, 2000mm, 2200mm, and 2500mm, and it runs well. The number of printing colors can reach 4-10 color groups, and gold ink, silver ink, etc. can also be produced. Special ink printing.

- It is more suitable for large-scale long-run printing. The preprinted plates are all made of steel chrome-plated electrogravure. The number of prints resistant to printing is 3 million to 4 million times, which reduces the time for changing plates and is particularly suitable for printing long lived prints.

- The corrugated box produced has a higher strength. Since preprinted corrugated cartons are produced on the production line, there is a certain amount of heat-forming time during the production, and the final production of corrugated cartons is high in strength and can avoid uneven coating and carton creases when the laminator is produced. , cardboard warping and so on.

(to be continued)