Comparison of common printing methods for several corrugated cartons

The cardboard box is an ordinary paper packaging product that is inseparable from our life and production. The printing quality of the corrugated box is not only related to the appearance quality of the corrugated box, but also affects the sales prospect of the packaged product and the image of the product manufacturing company. Therefore, it is particularly important to analyze how to improve the surface printing effect of corrugated boxes, how to choose a suitable printing process, and further reduce the processing cost of the carton. Here we will discuss these aspects.

First, the corrugated board processing process corrugated board processing technology is divided into two categories

1. Production process of automatic corrugated board production line The corrugated board production process is widely used, with advantages such as large production volume, large carton forming volume, and good quality of crucible type. The corrugated board produced by this process is usually made into cartons through processes such as water-based printing, slotting, sticking, and forming. The cartons produced by this process are mainly used for transport packaging.

2. Production process of semi-automatic corrugated board production line The corrugated board production process is to print the face paper first, and then combine it with corrugating medium paper and cardboard. The corrugated paperboard produced by the process is conventionally made into boxes by die-cutting indentation, adhesive nailing and the like. The carton produced by this process has good molding quality and good surface treatment effect. Carton boxes produced by this process can be used for sales packaging.

Second, the conventional carton printing methods General carton printing methods are mainly flexo, offset and screen printing three

1. Flexo-printing corrugated cartons Conventional flexo-printing corrugated cartons are printed directly on corrugated paperboard, using water-based inks, and so are known as watermarks. Flexo printing has the following features:

(1) Large format. The maximum width of the wide-format flexographic printing press can reach 2.5m~2.8m.

(2) The price is low. Flexographic prints have high resistance to print and can be reused; ink prices are also lower.

(3) It can be linked to production, such as printing, slotting, indentation, ordering (sticking) boxes, baling and so on.

(4) Less carton strength is reduced. Since flexo printing is light press printing, it has little effect on the strength of corrugated cardboard.

(5) The printing accuracy is not high, the conventional offset printing line number is 175 lines/inch, and the conventional printing line number of the flexible printing carton is 35 lines/inch~65 lines/inch, which belongs to the low-precision printing mode, and is most suitable for the line of printed text. Although the print quality of four-color images has improved in recent years, it still has limitations.

(6) There are difficulties in making plates, text lines are easy to make, and four-color images are more difficult to make.

(7) The stability of printing quality is not good, mainly reflected in the darkness of the printing ink. The flexographic plate direct printing process is suitable for the production process of the first type carton, and is currently widely used in the carton factory in China.

2. Offset Printing Corrugated Boxes Conventional Offset Printing Printing Corrugated boxes use the indirect printing method, which prints the carton face paper first, and then prints the printed face paper to the corrugated board.

Due to the relatively high resolution of the PS plate, very fine print patterns can be printed. At present, the vast majority of high-grade corrugated cartons used for sales and packaging in China are offset printing products. Offset printing corrugated boxes have the following characteristics:
(1) It is not suitable to use paperboard linkage production line. It is only suitable for single-faced corrugating machine and the production efficiency is low.

(2) Limited format, generally smaller than flexo print carton format.

(3) The printing products are very fine, and the number of screens can reach 150 lines/inch to 200 lines/inch.

(4) Plate making is easy. It is a conventional plate making of PS plate.

(5) Can finish the surface decoration, such as laminating, polishing and so on.

(6) High printing costs.

(7) The printing quality is relatively stable.

3. Screen printing corrugated box

The screen printing corrugated box process uses direct printing. Since the ink ratio of the screen printing plate is proportional to the hole pitch of the screen, the resolution of the screen printing is not high, and the image accuracy is low. The number of conventional screen lines is 60 lines/inch to 80 lines/inch. Screen printing corrugated boxes have the following characteristics:

(1) It is not suitable for the linkage production line and the production efficiency is low.

(2) The printing format can be large or small.

(3) The printing can be completed before pairing and boxing, and printing can also be performed after pairing and boxing.

(4) Suitable for printing non-fine products. The screen printing ink is thick, so its color saturation is high and the visual effect is strong, especially the spot color printing is better in the field.

(5) Plate making is easy and plate making cost is low.

(6) Low printing costs.

(7) The printing quality is relatively stable.

Third, the new printing system box

1. When the plastic gravure compound carton process adopts a single-faced corrugated production line, if the glossy paper needs to be coated after printing, and the production volume is large, it may not be printed on the surface paper, but may be printed on the plastic film by a gravure printing method. The gravure printing is completed, and the white base is added. Then the printed plastic film is first compounded with the facial paper, and then the box is formed according to the conventional carton forming process. The characteristics of this process are:

(1) The cost of carton production is low.

When the production volume is large, such a process can greatly reduce the printing cost of the tissue paper and the material cost of the tissue paper. Because the noodle paper does not need to be printed, non-coated white paper can be used, so that the cost of the noodle paper is greatly reduced.
(2) beautifully printed. Because plastic gravure is used, the printing effect can be comparable to that of offset printing. It is necessary to pay special attention to the fact that in the process of plate making, full consideration should be given to the dimensional change and deformation of the plastic film; otherwise, the carton face paper will be misaligned with the lower cardboard.

2. Coated paper gravure composite carton process When the production volume is relatively large, do not need to film, and requires good printing effect, low cost, you can use this process. The process is to use a paper gravure printing machine to print thinner coated paper, and then composite this finely-printed coated paper with ordinary slagboard or boxboard paper. The whole is used as cartonboard paper, and then it is used for confrontation and normal carton forming. Processing. The characteristics of this process are:

(1) The cost of carton production is low. The main reason for the reduction in cost is to convert whiteboard paper to low-weight coated paper in combination with cheap linerboard, which reduces material costs.

(2) beautifully printed. Paper gravure printing is very beautiful.

(3) Gravure printing plates are more complicated and costly, and are not suitable for printing carton products that are often revised.

(4) The operation and control methods of the printing process, such as paper compounding and box making, should be carefully explored, accumulated, and reasonably implemented. Otherwise, it is easy to increase the scrap rate.

3. Direct offset corrugated carton process Corrugated carton direct offset process is currently relatively mature abroad, it is the corrugated board directly on a special offset press for printing. Suitable for processing thin corrugated boxes.

The process can not only guarantee the good moldability of the carton, but also can complete the exquisite glossy paper printing. However, the printing machine used is relatively expensive. At present, it is not yet in line with China's demand standards, and it is not suitable for the carton industry in the near future. However, in the next few years, this process may become a new direction for the development of high-end carton printing in China.

4. Flexo preprinted and gravure preprinted corrugated box processes

This year's development is relatively fast, both of these processes are first to use web printing paper, and then complete the production of corrugated cardboard in the automatic corrugated board production line. Carton printing quality and molding quality are relatively high, but the investment is relatively large and it is not suitable for small batch production.

In the domestic carton industry, the application of three conventional corrugated box printing methods is relatively common and has become the mainstream method for corrugated box printing. The new type of printing box method, due to the hot spots of equipment, materials, processes, operations and other technology has not yet been fully grasped, the investment is relatively large, the promotion of the difficulty is still relatively large. However, in order to improve the quality of cartons, reduce the total cost of the cartons, obtain maximum profits, and increase the competitive advantage in the market, it is imperative to adopt a new type of box-making technology.

From the general development of the carton printing process, the plate making and printing technology of the flexographic plate printing corrugated box process needs to be improved as a whole. The plastic gravure printing, the carton gravure printing and the web offset printing process need to be promoted and improved. Direct offset printing and preprinting Corrugated box production process should also arouse our concern.

Reproduced from: China and Hong Kong silk screen network