In the production process of labels and self-adhesive labels, the printing process is very important, which determines the actual presentation of the design.  This article will detail the label printing process involved in screen printing, gravure printing, UV printing, offset printing, digital printing, thermal transfer printing process, characteristics and applications.

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1.Screen Printing

Screen printing is a perforated printing technology, the basic principle is to use the screen as the plate base, through the photographic plate making method to make a screen printing plate with graphics. In the printing process, the ink in the squeezing of the squeegee, through the mesh of the graphic part of the transfer to the substrate, the formation of the same as the original graphic.

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Applications

Glass packaging industry: for text or pattern printing on glass container products.

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Plastic packaging industry: plastic film packaging printing, to protect items from external influences.

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Metal packaging industry: packaging printing on metal containers, requiring strong ink adhesion and friction resistance.

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Paper packaging industry: pattern printing on paper, improve product packaging grade.

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Ceramic packaging industry: pattern printing on ceramic products to increase the sense of beauty.

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Characteristics

Strong adaptability:‍Can print on flat, curved, spherical and concave-convex surfaces.

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Thick ink layer:The ink layer thickness of screen printing is generally up to 30μm, with a strong sense of three-dimensionality.

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Bright colors:Using a variety of inks and coatings, strong color expression.
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Strong light resistance:Suitable for outdoor advertising, signs and other printed materials exposed to sunlight for a long time.
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Flexible printing format:Can carry out large-area or ultra-small, ultra-high-precision printing of special items.
Easy to operate:
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Simple equipment, easy to operate, suitable for individual manual production and mechanized production.

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Gravure Printing

2.Gravure Printing

Gravure printing is a direct printing method whose core principle is to utilize the depression of the graphic portion of the intaglio plate to store ink and transfer the ink to the substrate through the pressure of the printing press to form clear patterns and text.

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Characteristics

Thick ink layer: The thickness of the ink layer of gravure printing is usually thicker than other printing methods, and can reach more than 20μm, which makes the color of the print more vivid and three-dimensional.

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Vivid colors: Due to the thick ink layer, gravure printing can achieve highly saturated color effects, suitable for printing high-quality color images.
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High print resistance: Gravure printing plates are durable and can withstand millions of printings, making them suitable for mass production.

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Wide range of application: Gravure printing is suitable for a wide range of substrates, including paper, plastic film, metal foil, etc., and can meet the printing needs of different products.

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Continuous printing: Gravure printing machine can carry out high-speed continuous printing, which is suitable for the production of long version of printed materials.

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Good anti-counterfeiting performance: Gravure printing is commonly used in the printing of securities, anti-counterfeiting labels and other products, because its printing pattern is difficult to copy.

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Applications

Packaging Printing: Gravure printing is widely used in the packaging industry, especially in the printing of plastic flexible packaging, cartons, labels and other products, which can provide high quality printing results.

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Publication printing: In Europe and the United States, intaglio printing is commonly used in newspapers, postal advertising and other high-volume print production.

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Valuable Printing: Gravure printing for its good anti-counterfeiting properties, suitable for currency, stamps, securities and other securities printing.

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Decorative printing: In decorative materials, such as wallpaper, decorative materials, etc., intaglio printing can print continuous patterns to increase the aesthetics of the product.

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Industrial printing: In the industrial field, gravure printing is used for printing circuit boards, decorative films for electronic products, etc. It is favored for its fine lines and thick ink layer.

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UV Printing

3.UV Printing

The core of UV printing technology lies in the UV ink and the curing process.UV ink is a specially formulated ink whose key components are capable of curing rapidly to form a skin film under ultraviolet light.

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UV Ink and Curing Technology

The core of UV printing technology lies in the UV ink and curing process.UV ink is a specially formulated ink whose key components are capable of curing rapidly to form a skin film under ultraviolet light.

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Composition of UV inks

Pre-polymer: as the main component of the ink, usually accounts for 50-70% of the total ink.
Monomer: as the active diluent, adjust the viscosity of the ink and improve the printing performance of the ink.
Photoinitiator: generates free radicals under ultraviolet irradiation to initiate the polymerization reaction of prepolymer and monomer.
Pigment: Provides the color of the ink, which can be organic or inorganic pigment.

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Curing process:

UV curing is a photochemical reaction in which liquid UV inks are rapidly cured under UV irradiation.
The curing speed is affected by a variety of factors, including the intensity and wavelength of the UV light source, the thickness of the ink layer, and the light transmittance of the substrate material.
The power density of the UV lamp is critical to the curing effect, the general common specifications are 40W/cm to 2000W/cm ranging.

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Advantages and limitations

UV printing technology in the modern printing industry has obvious advantages, but there are some limitations.

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Advantage:

Fast curing: UV ink cures instantly under ultraviolet light, significantly improving production efficiency.
Environmentally friendly: UV inks do not contain volatile organic compounds (VOCs) and are friendly to the environment.
Wide applicability: UV printing is suitable for a wide range of substrates, including non-absorbent and absorbent materials.
High gloss: The UV-cured ink layer has a high gloss and is resistant to abrasion and corrosion.
Space-saving: No need for powder spraying and long drying time in traditional printing, saving space for post-printing treatment.

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Limitations:

Cost: The cost of UV ink and curing equipment is relatively high, increasing production costs.
Technical Requirements: Specific requirements for the temperature and humidity of the operating environment, which need to be precisely controlled to ensure printing quality.
Ink Adhesion: UV ink in the curing process may produce large internal stress, affecting the ink adhesion to the substrate.
Equipment maintenance: UV lamps have a service life limit, need to be replaced regularly, and maintenance costs are high.
Color performance: On some materials, the color saturation of UV printing may not be as good as traditional inks.

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4.Offset Printing

Offset printing, also known as lithography, is a widely used indirect printing technique. Its core principle is based on the mutually exclusive nature of ink and water, and the transfer of printed graphics is achieved through the interaction of graphic and non-graphic parts.

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Indirect Printing Principle

Offset printing, also known as lithography, is a widely used indirect printing technique. Its core principle is based on the mutually exclusive nature of ink and water, and the transfer of printed graphics is realized through the interaction of graphic and non-graphic parts.

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Printing Principle:

The printing plate of offset printing is flat, the graphic part and the blank part are in the same plane, but the surface energy is different. The graphic part of the oleophilic hydrophobic, while the blank part of the hydrophilic oleophobic.

In the printing process, first of all by the fountain plate water roller to the printing plate cylinder hydrophilic non-graphic part coated with fountain solution, and then by a number of inking rollers to the printing plate cylinder oleophilic (pro-ink) graphic part of the ink.

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The ink and the fountain solution form a stable distribution on the printing plate. Subsequently, the ink is transferred to the blanket roller through the plate roller, and then transferred to the substrate by the blanket roller under the action of the impression cylinder to form the printed matter.

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Features:

Offset printing is an indirect printing method in which the ink is first transferred to the blanket and then to the paper or other substrate.
Offset printing can achieve high-quality printing results, clear graphics, bright colors, suitable for mass production.
Offset printing machine can handle a variety of substrates, such as paper, plastic, metal, etc., with a wide range of applicability.
Offset printing utilizes water-ink balance technology to ensure print quality by precisely controlling the amount of ink and fountain solution.

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Quality Control and Application

The quality control of offset printing is a key link in ensuring printing quality, involving a number of aspects such as printing pressure, water-ink balance, overprint accuracy, etc.

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Printing pressure: Appropriate printing pressure ensures uniform ink transfer and avoids blurring of the print or damage to the paper caused by too much pressure.

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Ink and water balance: Precise control of the pH value and dosage of the fountain solution ensures stable ink transfer and cleanliness of the printing plate.

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Overprint accuracy: Through precise equipment adjustment and monitoring, it ensures accurate overprinting of each color plate during multi-color printing to avoid color distortion.

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Color Management: Use color control system to ensure the consistency and accuracy of printing colors to meet the high standard requirements of customers.
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Printing Materials: Choose the right paper and ink, different paper's ink absorption and surface characteristics will affect the printing effect.

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Areas of application

Packaging Printing: Offset printing is widely used in the packaging industry, such as food packaging, cosmetic packaging, pharmaceutical packaging, etc., providing exquisite visual effects and good printing quality.

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Publication Printing: Printing of books, magazines, newspapers and other publications, offset printing can meet the demand for high-volume, high-quality production.

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Commercial Printing: Business cards, letterheads, envelopes and other commercial printing, offset printing provides stable and efficient printing services.

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Advertising Printing: Billboards, posters, brochures, etc., offset printing can achieve high-definition and colorful printing effects to attract the attention of the target audience.

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5.Digital Printing

Digital printing is a production method that uses digital technology for printing, which directly controls the printing machine through digital files without the need for plate making, allowing for fast and flexible printing services.

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Technical features

Digital file direct printing: Digital printing does not require the traditional plate-making process, digital files are directly transmitted to the printing equipment to achieve rapid printing.

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Variable Data Printing: Each print can be different, suitable for personalized printing needs, such as variable bar codes, personalized images, etc.

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Instant printing: Digital presses can instantly adjust printing parameters to adapt to different order requirements and shorten production cycles.

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Cost-effective small batch printing: Without the need for large-scale plate making, small batch printing is less costly and suitable for on-demand printing.

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Color Management: Digital printing presses are equipped with a high-precision color management system to ensure color consistency and accuracy.

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Environmentally Friendly: The digital printing process does not require the use of chemicals and produces less waste products and wastewater, which has a low impact on the environment.

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Technical Advantage

Fast Response: Digital printing can quickly adjust printing parameters to adapt to urgent orders and rapidly changing market demands.

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Personalized service: Meet personalized printing needs, provide customers with customized services, and increase the added value of products.

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Flexible Printing Options: Digital printing can easily handle a variety of file formats and support a wide range of substrates, providing diverse printing options.

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Cost Effectiveness: Small batch printing and print-on-demand are cost-effective for short runs and testing market response.

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Color Consistency: The digital press's color management system ensures color consistency from print to print, meeting high standards of print quality.

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Personalized Printing Applications

Personalized printing is an important application area of digital printing technology, which meets the market demand for personalized products and provides customers with customized printing services.

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Application areas

Labels and Hangtags:Personalized labels and tags can be used for product identification, brand promotion, etc.

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Personalized gifts: Such as customized T-shirts, cups, photo albums, greeting cards, etc. Consumers can design patterns and text according to their own preferences.

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Business promotional items: Personalized brochures, business cards, posters, etc., to help companies enhance their brand image and market competitiveness.

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Packaging Printing: Personalized packaging can enhance the uniqueness and recognition of products and attract consumers' attention.

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6.Heat Transfer Printing

Heat transfer printing is a printing technique in which a design or text is transferred to the surface of a substrate by heat pressure. The core of the technology lies in the heat transfer ink and special transfer paper or film.

Transfer process

Heat sublimation transfer: Using sublimation ink printed on special paper, the dyes in the ink are transferred to the substrate through high temperature and high pressure to form a penetration effect.

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Heat transfer stamping: Printing pattern on PET sheet and coating hot melt adhesive on the back side, transferring the pattern and adhesive layer to the substrate through hot pressure, forming a layer of image attached to the surface.

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Features: Wide applicability: suitable for a variety of materials, such as plastic, metal, ceramics, fabrics, etc.

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Bright color: the pattern after transferring is full of color and has a high degree of reproduction.

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Strong durability: the pattern after heat transfer has good resistance to washing and friction.Easy to operate: suitable for small batch production and personalized customization.

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Applications

Clothing industry: transfer personalized patterns and text on T-shirts, hats, shoes and other clothing to meet personalized needs.

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Home decoration: transfer printing patterns on cups, plates, tiles and other household products to increase the beauty and personalization of the products.

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Outdoor advertising: transfer printing advertising content on billboards and banners to improve the visual effect of advertising.

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Industrial manufacturing: transfer printing logo, warning labels, etc. on various industrial products to improve product recognition and safety.

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Anti-counterfeiting labels: produce anti-counterfeiting labels and holograms for product anti-counterfeiting and brand protection.

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