(2) Specification of base plate. The substrate layout of packaging printing not only has the common specifications of general printing paper, but also has substrates as large as 3m and as small as 1m; The thickness of the substrate is as large as 3 ~ 4 layers of composite corrugated cardboard and as small as 0.025mm thick film.
(3) the surface of the substrate. In addition to the plane, there are convex, concave, curved and various molded objects on the surface of the substrate. Understanding the diversity of substrates is of great significance for selecting printing methods reasonably, ensuring the quality of printed products and reducing printing costs.
Adaptability of printing method
The diversity of substrates determines that packaging printing has good adaptability to various printing methods.
Up to now, several main printing methods can be used for packaging printing, such as relief printing, offset lithography, gravure printing, screen printing and flexographic printing. However, it is difficult to choose a reasonable printing method in order to obtain high quality and low price packaging printed matter. Therefore, in practical application, the ideal printing method should be reasonably selected according to the purpose, printing requirements, the nature and surface shape of printing materials. The following principles can be used for reference.
(1) letterpress printing.
Main features: clear graphics and text, suitable for line draft packaging and printing, thick ink color and bright colors.
Application examples: trademarks, wrapping paper and packaging cartons, self-adhesive printing, etc. At present, it is mainly used to print small-sized parts.
(2) offset lithography.
Main features: clear dot, rich hierarchical recognition, good color reproducibility and wide application.
Application examples: samples, advertisements, trademark printing, metal printing, etc.
(3) Gravure printing.
stock
Main features: thick ink layer, strong three-dimensional sense and distinct layers, suitable for printing of soft packaging materials.
Application examples: various plastic films, composite paper bags, wallpaper and building materials printing, etc.
(4) Flexographic printing.
Main features: it is suitable for all kinds of printing materials, and can achieve good results for all kinds of line drafts and general dot printing, and the cost is relatively low.
Application examples: soft package printing, label printing, corrugated board printing, packaging carton printing, pollution-free printing can be realized by using water-based ink, which is widely used in medicine and food packaging printing.
(5) screen printing.
Main features: thick, heavy and durable ink layer, suitable for printing of various printing materials and molded products.
Application examples: printing of paper, cardboard, fabric and various packaging containers.
Complexity of printing and adaptability of post-press processing
In packaging printing, on the one hand, different printing materials and different printing plates. Different inks have different printability; On the other hand, in order to protect the printing surface, improve its surface gloss and obtain special visual effects, post-press treatments such as glazing, laminating, bronzing, indentation and die cutting are often needed after printing. Therefore, higher requirements are put forward for the printability and post-press processing adaptability of packaging printing. This requires a comprehensive understanding of the adaptability of printing and post-press processing, and constantly summing up and accumulating experience in order to get good printing and post-press processing effects.
High quality and high benefit of products
Generally speaking, because the main function of packaging and printing is to beautify and publicize products, promote sales and improve sales value, the quality of packaging and printing products is mostly medium. High-end products In addition, in order to maximize the quality of printed matter, new technologies, new processes and new materials are often applied in packaging and printing first, so that the quality of printed matter is always in the leading position. In other words, packaging printing is to occupy the market with high quality and obtain high efficiency with high quality. This is also one of the important reasons why the packaging and printing industry has attracted worldwide attention in recent ten years.