Corrugated carton processing and different printing methods (on)

Corrugated cartons are an ordinary paper packaging product that is inseparable from our lives and production. The printing quality of corrugated cartons is not only related to the appearance quality of corrugated cartons, but also affects the sales prospects of the packed products and the image of the commodity production companies. 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, corrugated board processing technology

Corrugated board processing technology is mainly divided into two categories.

1. Production process of automatic corrugated board production line

The corrugated board production process has been widely applied, and has the advantages of large production volume, large carton forming volume, and good quality of the 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 surface paper first, and then it is coupled with the corrugating medium core 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. The cartons produced by the compromise process can be used for sales packaging.

Second, the conventional carton printing

Conventional carton printing methods include flexo, offset and screen printing.

1. Flexo printing corrugated carton

The conventional flexographic printing corrugated box process prints directly on corrugated board, using water-based inks, so it is also a process of watermarking.

Flexo printing has the following features:
(1) Large-format, wide-format flexographic printing presses have a maximum width of 2.5 to 2.8m.
(2) The price is low, flexographic prints are very resistant to print and can be reused; humor 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, there is little effect on the strength of corrugated cardboard.
(5) The printing accuracy is not high, the number of conventional offset printing screens is 175 lines/inch, while the number of conventional screen printing lines in flexo-printing boxes is 35~65 lines/inch, which is a low-precision printing method, and is most suitable for printing text lines and four colors. Although the image printing quality has improved in recent years, there are still 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 carton

The conventional offset printing corrugated box adopts the indirect printing method, that is, the cardboard box is first printed, and the printed sheet is then affixed to the corrugated font. Due to the relatively high resolution of the PS version, very fine printing patterns can be printed. The vast majority of high-grade corrugated cartons used for sale 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 product is very fine, and the number of screens can reach 150~200 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 boxes

The screen printing corrugated box process uses direct printing.

Since the ink ratio of the screen plate is proportional to the hole pitch of the screen, the resolution of the screen printing is not high, the image accuracy is low, and the number of conventional screen lines is 60 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 printed matter is relatively stable.

(to be continued)