Gravure printing is known as a high-quality solution for flexible packaging production. However, ink smearing in gravure printing remains a challenge for many converters. Even small smears can blur images, distort colors, and lower product value. To maintain sharp and stable print quality, understanding the causes and how to prevent smearing is essential. This article explains the mechanism, reasons, and effective solutions to minimize ink smearing.
WHAT IS INK SMEARING IN GRAVURE PRINTING?
Ink smearing in gravure printing occurs when ink spreads beyond its intended area, making images blurry with unclear edges and mixed colors. This reduces product aesthetics and brand value. At high printing speeds, ink may fail to dry properly or adhere unevenly, spreading across the film surface. The problem often occurs on OPP, PET, or PE films that are poorly surface-treated.
Ink smearing not only damages the print surface but also increases waste and production time. For packaging manufacturers, this directly affects efficiency and overall cost.
CAUSES OF INK SMEARING IN GRAVURE PRINTING
Ink-related causes
A major cause of ink smearing in gravure printing is low ink viscosity. When viscosity is unstable, ink flows uncontrollably across the cylinder surface. Slow solvent evaporation also contributes to the issue. If the ink has not fully dried before the next layer is printed, smearing and offsetting occur.
Using the wrong ink for a substrate—for example, PE ink on PET film—reduces adhesion. As a result, the ink slips and spreads beyond the desired print area.
Process-related causes
Printing conditions greatly affect ink smearing in gravure printing. When printing speed is too high, drying time is shortened, leading to smearing. Uneven pressure between cylinders also causes inconsistent ink transfer. The doctor blade controls ink amount on the cylinder. A worn or misaligned blade leaves excess ink, resulting in blurred images.
Inadequate or uneven drying temperature prevents complete solvent evaporation. As a result, subsequent layers overlap wet areas, creating color blending and smeared edges.
Substrate-related causes
The film surface plays a decisive role in ink adhesion. If corona treatment is insufficient or surface energy is low, ink cannot wet the surface evenly, causing streaks and color bleeding. Contaminants such as oil, dust, or slip additives left on the film also block adhesion. These create a barrier between ink and substrate, increasing the risk of ink smearing in gravure printing.
High humidity in the printing area worsens the issue. When moisture condenses on the film, the surface becomes slippery, reducing ink wetting and promoting smearing.
SOLUTIONS TO PREVENT INK SMEARING
Adjusting ink and solvent
To reduce ink smearing in gravure printing, keep ink viscosity within the manufacturer’s recommended range. If the ink is too thin, add resin or viscosity modifiers to stabilize it. Fast-evaporating solvents should be blended carefully to avoid premature drying on the cylinder. Stirring and filtering ink regularly ensures consistency and prevents phase separation.
Using dispersing or stabilizing additives helps maintain color clarity and reduces smearing. These specialty products enhance print sharpness and layer durability.
Optimizing printing parameters
Printing speed must be properly adjusted for each ink and substrate type. Excessive speed prevents full drying, leading to smearing and color distortion. Pressure between cylinders must be balanced to ensure even ink transfer. The doctor blade should be inspected regularly. Proper angle and pressure guarantee uniform ink coverage and prevent excessive build-up. Meanwhile, the drying unit must maintain sufficient heat to fully dry the ink before rewinding.
A stable drying system allows even solvent evaporation, resulting in sharper and more durable prints. This not only minimizes smearing but also extends equipment life.
Controlling and treating the print surface
Before printing, ensure the film surface is clean and has adequate surface energy. Corona or plasma treatment improves adhesion and color stability. An optimal surface energy above 38 dyn/cm helps ink wet the surface evenly. Films stored for long periods should be retested before use.
Cleaning the film with mild solvent wipes removes oil, dust, and slip residues. This process enhances adhesion and significantly reduces ink smearing in gravure printing.
VICHEM – AUTHORIZED DISTRIBUTOR OF COVESTRO, SINOPEC, AND TINOX CHEMICAL ADDITIVES IN VIETNAM
Vichem is the official distributor of chemical additives from leading brands such as Covestro, Sinopec, Tinox, and TotalEnergies,… All products comply with Vietnam’s regulatory standards. We not only supply premium materials but also deliver international-standard technical services. Our services include:
- Technical consulting: Guiding customers to select suitable materials for their specific applications.
- Color matching tests: Our experts conduct color evaluation to ensure results meet design requirements.
- Application support: Assisting customers in integrating products into their production lines for optimal performance.
For more information, please contact us through the following channels:
📞 Hotline: 08 1790 1790
📧 Email: contact@vichem.vn
🔎 LinkedIn: Vichem JSC
🌐 Website: www.vichem.vn
📌 Facebook: Vichem JSC
