Table of Contents
Packaging printing is an important means and way to increase the added value of commodities, enhance the competitiveness of commodities, and open up markets. Designers should understand the necessary packaging and printing process knowledge to make the designed packaging works more functional and beautiful. Different packaging materials will have different printing processes. Collect and sort out the content of this issue to share the relevant knowledge of printing processes.
Printing method
There are many methods of paper packaging printing, the method is different, the operation is also different, and the printing effect is also different. Traditionally used printing methods are mainly divided into the following four categories:
Letterpress printing
Letterpress printing means that the graphic part on the printing plate is higher than the non-graphic part, the ink on the ink roller can only be transferred to the graphic part of the printing plate, and the non-graphic part has no ink, thus completing the printing of the printed matter.
If the back of the printed matter has a slightly raised impression, the edges of the lines or dots are neat, and the ink appears light in the center, it is a relief print.
Gravure printing
In contrast to letterpress printing, the graphic portion of the printing plate is lower than the non-graphical portion, forming grooves. The ink is only covered in the groove, there is no ink on the surface of the printing plate, the paper is covered on the upper part of the printing plate, the printing plate and the paper are pressurized, and the ink is transferred from the concave part of the printing plate to the paper.
The printed products of gravure printing have thick ink layers and bright colors, and the printing plate has the advantages of high printing durability, stable printing quality and fast printing speed, so it has been widely used in practice.
Offset printing
The graphic part and the non-graphic part of the printing plate keep the surface flat, the graphic part is covered with a layer of oily oil film, and the non-graphic part absorbs appropriate moisture. When ink is applied, the graphic and text parts repel water and absorb ink, and the non-graphic and text parts form an anti-ink effect due to absorbing water.
Tip: Because the lithographic method is simple to work and low in cost, it has become the most used method in printing.
Screen printing
Screen printing means that under the action of the scraper, the ink leaks from the mesh of the graphic part to the substrate, while the screen mesh of the non-graphic part is blocked, and the ink cannot leak to the substrate, thus Complete printing of printed matter.
Tips: Screen printing can also be used for large-area printing, and the maximum size of printed products can reach 3 meters by 4 meters, or even larger.
Printing process
There are many printing processes for paper packaging, here are some commonly used printing processes:
Hot stamping process
The expression method of hot stamping process is to make the required hot stamping or hot silver pattern into a convex plate and heat it, then place the aluminum foil paper of the required color on the printed matter, and after pressing, the aluminum foil will adhere to the printed matter.
Tip: There are many kinds of bronzing paper materials, including gold, silver, laser gold, laser silver, black, red, green and so on.
Laminating process
The laminating process is a surface processing process after printing, which refers to a product processing technology formed by covering a layer of transparent plastic film on the surface of a printed product with a laminating machine.
Tips: The surface of the coated printed matter will be smoother, brighter, stain-resistant, water-resistant, and wear-resistant.
Concave-convex embossing process
This process is to use the high pressure of the letterpress printing machine to press the partial patterns or characters on the semi-finished products that have been printed into three-dimensional graphics with obvious concave and convex.
Note: The concave-convex embossing process is mostly used in the post-processing of printed matter and paper containers. In addition to packaging cartons, it is also used in the printing of bottle labels, trademarks, bookbinding, calendars, greeting cards and other products.
UV anti-metal etching printing process
UV anti-metal etching printing, also known as matte or sand surface printing, is to print a layer of uneven translucent ink on substrates with metallic mirror luster (such as gold and silver cardboard), and then cured by ultraviolet light (UV). , producing an etched or brushed effect similar to a shiny metal surface.
Note: UV anti-metal etching ink can produce suede and matte effect, which can make the printed matter appear soft and solemn, elegant and luxurious.
In addition to the several printing processes introduced above, the paper packaging printing process also includes printing processes such as refraction, die-cutting and indentation, hydrothermal transfer, drop plastic, ice flower, and scrape silver.
Packaging commonly used process
Four color printing
The so-called four colors are: cyan (C), magenta (M), yellow (Y) and black (K) four inks, all colors can be formed by mixing these four inks, and finally realize color graphics.
In the most common and common printing, the printing effect is different on different substrates.
Spot color printing
Spot color printing means that a special ink is used to print the color during printing, which is more vivid than the color mixed by four colors. Commonly used are special gold and special silver.
There are many spot colors. Refer to the Pantone color card. Spot colors cannot achieve gradient printing. If necessary, add four-color printing.
Clear glue
After printing, a transparent plastic film is applied to the surface of the printed matter by hot pressing to protect and increase the gloss. The surface is bright, as shown in the picture below.
The most basic process of carton surface treatment. There is also varnish similarly, but gluing can enhance the hardness and tensile properties of paper.
Matt film
After printing, a transparent plastic film is applied to the surface of the printed matter by hot pressing to protect and increase the gloss. The surface is matte, as shown in the picture below.
The most basic process of carton surface treatment is similar to varnish, but gluing can enhance the hardness and tensile properties of paper.
U V
Partial glazing is applied to the prominent parts of the printed matter to make the partial pattern more three-dimensional.
Printed with matte glue process, there is no effect when glossy glue is used.
Hot stamping
Hot stamping uses the principle of heat transfer to transfer the aluminum layer in anodized aluminum to the surface of the substrate to form a special metallic luster effect.
The printing materials include gold, silver, red, green, blue and other colors, but hot stamping can only be monochromatic, and there are many kinds of colors, but not all colors are available in the market.
Convex
Use a set of concave and convex templates corresponding to the yin and yang of the graphic, place the substrate between them, and press out the embossed concave-convex graphic by applying a large pressure.
Paper of various thicknesses is acceptable, but cardboard cannot be embossed.
Coding
The process of using the inkjet printer to print the logo (production date, shelf life, batch number, company logo, etc.) on the product.
It can print simple character patterns with greater flexibility.
Blister
- Blister is a transparent material, the main raw material is PVC, PE, or PET.
- It can directly replace the paper to make the box, and can also be used to form a card.
- It can be used to fix the product inside the package, which is called inside the blister.
- It can be screen printed, printed, or hot stamped.
- It can be printed on the machine, but the printing cost is relatively high, and silk screen printing is generally used for small-scale production.
EVA
The chemical name is ethylene-vinyl acetate copolymer. The finished product made of it has the characteristics of good flexibility, shockproof, non-slip and strong pressure resistance.
Used in packaging and inside to fix and protect products.
There are a variety of colors to choose from, and the surface can be flocked or wrapped in fleece to enhance the visual effect.
Sponge
It is a porous material with good elasticity. The density of the holes is different, and the elasticity is different.
Used in packaging and inside to fix and protect products.
There are a variety of colors to choose from, which are generally used directly without superimposing crafts.
Commonly used packaging materials
Single powder
Commonly used carton materials, the paper thickness ranges from 80g to 400g, and for higher thicknesses, two sheets are required for mounting.
One side of the paper is glossy and the other side is matte, only the glossy side can be printed.
It can be printed in various colors, and there is no limit to the color.
The commonly used surface treatment processes after printing are: gluing, UV, hot stamping, and embossing.
Pit paper
Compared with ordinary paper, it is straighter and has a stronger load-bearing capacity.
Commonly used are single pit, double pit and triple pit.
It can print in various colors, but the effect is not as good as that of a single powder.
The commonly used surface treatment processes after printing are: gluing, UV, hot stamping, and embossing.
Cardboard
It is used to make a gift box structure, and the surface is mounted with a layer of single-powder paper or special paper.
The commonly used colors are black, white, gray and yellow.
There are also various grades of cardboard thickness, which can be selected according to the load-bearing needs.
If it is mounted with a single powder, the process is the same as that of the single powder carton; if it is special paper, most of it can only be hot stamped, and some can be simply printed, but the printing effect is not good.
Specialty paper
There are many types of special paper, here we only talk about the ones used in our packaging materials: embossed paper, patterned paper, pearlescent patterned paper, metallic patterned paper, gold paper, etc.
These papers are specially treated to enhance the quality of packaging. Embossing and embossing can not be printed, only hot stamping on the surface, star color, gold, etc. can be printed in four colors.
Gold and silver cardboard
Use UV transfer printing technology to coat a layer of UV oil on the surface of the paper through the blanket, and then transfer the light column film or specific patterns to the printed paper through the roller, so that the surface of the paper produces light columns with the effect of laser paper.
It can only be printed with a UV machine, and various pattern effects can be realized. It is more textured than ordinary paper and has different types of gloss. But the cost is relatively dry.
The common process of other materials
Paint
Spray several layers of paint on the base that has been polished to a certain degree of roughness, and bake it at a high temperature to set it.
There are many kinds of colors, please refer to the Pantone color card. But it can only be a solid color, not a gradient color.
Oxidation
For the surface treatment process of aluminum or aluminum alloy, oxidation treatment generates a surface oxide film on the surface.
Color is optional, refer to the Pantone color card. Compared with baking varnish, it adds a metallic texture, but it can only be in solid color and cannot show gradient colors.
Carbon fiber
It is a new type of fiber material with high strength and high modulus fiber containing more than 95% carbon. It has electrical and thermal conductivity, corrosion resistance, high-temperature resistance, wear resistance, lightweight, radiation protection and other materials that cannot be compared with its superior performance.
After processing, the texture of the carbon fiber itself is presented, and the color can be selected.
Plating
The process of plating a thin layer of other metals or alloys on some metal surfaces by using the principle of electrolysis.
Gold plating, silver plating and chrome plating are commonly used.
Silkscreen
Through the extrusion of the scraper, the ink is transferred to the substrate through the mesh of the graphic part, forming the same graphic as the original.
There are many colors for silk screen printing, refer to the Pantone color card, but gradient printing cannot be achieved.
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