[Chinese Packaging Network News] First, the characteristics of the printing plate substrate material do not cause ink color printing issues.
In reality, maintaining consistent packaging printing pressure is a key condition for ensuring stable ink quality in packaging printing. Several factors influence packaging printing pressure, including equipment accuracy and the properties of the base material used for the printing plate. For example, in letterpress and rotary press systems, copper, zinc-plated, or resin plates are commonly used for packaging printing, and these require a backing board to secure the printing plate during the process. This backing board plays a crucial role in maintaining even pressure, so it must be solid, firm, and resistant to deformation to ensure consistent ink transfer and high-quality results. Traditional plywood has been widely used as a backing material, but it comes with several disadvantages, such as low durability, susceptibility to overprinting, and poor ink transfer. These issues often lead to uneven or insufficient ink layers on the printed surface due to the wood's instability and tendency to deform. To avoid this, proper padding techniques should be applied. When using a backing board, it's essential to ensure even and uniform padding. For larger printing areas, metal die-cutting plates—such as magnetic trays or aluminum trays—are recommended. These metal backing boards offer better flatness, strength, and resistance to compression, which help maintain stable printing pressure and reduce ink-related defects.
Second, poor machine conditions or improper adjustments can also cause ink blooming.
As machines age, components like the roller shafts, bearings, gears, racks, and ink rollers may experience wear and looseness, affecting the stability and uniformity of the printing pressure and ink distribution. If a large-area print is produced under such conditions, ink blooming is more likely to occur. To prevent this, regular maintenance of the equipment is essential, especially for parts like the impression cylinder and ink roller bearings. Keeping these components well-lubricated and preventing excessive wear will help maintain smooth operation. Additionally, improper positioning of the ink roller can also lead to ink blooming. The contact between the ink roller, the fountain roller, and the printing plate must be even and properly adjusted to avoid ink defects caused by poor contact.
Third, improper lining materials can contribute to ink blooming.
Lining serves as a medium for transferring pressure and ink during the printing process. The material and condition of the lining directly impact ink quality. If the lining has a high deformation coefficient or poor flatness, it can cause ink to bloom on the printing plate. Therefore, it’s important to choose appropriate lining materials based on the specific requirements of the packaging and printing job. For soft resin plates or textured plates, rigid linings with low deformation, high toughness, and good flatness—such as cardboard, kraft paper, or insulation paper—are ideal. On the other hand, when using hard copper or zinc-plated plates, which have lower gloss and ink affinity, elastic materials like cloth, blankets, or fine-grained fabric are more suitable. These materials help prevent ink defects and ensure consistent print quality.
Fourth, ink discoloration due to the printing material.
When using zinc plates for large-area printing, ink blooming is also common. This occurs because oxidation on the plate surface creates a "sand-eye" effect, and if the baking temperature or etching solution is too high, the ink may not adhere properly. As a result, the ink layer may not make good contact with the printed surface, leading to ink defects. To address this, the printing plate surface can be gently sanded with charcoal to reduce roughness. Increasing the printing pressure and ink supply during the process can also help. For fine print packaging, it's best to use solid resin plates, which are softer and offer better gloss and ink adhesion. This helps avoid ink bleeding and ensures a high-quality finish.
Fifth, ink blooming caused by poor paper quality.
Production experience shows that rough paper surfaces tend to absorb more ink due to the gaps between fibers. These uneven surfaces may not make proper contact with the printing plate, requiring more ink to achieve the desired coverage. If the printing pressure is too low or the ink layer is too thin, ink blooming can occur on the printed product. Therefore, when working with low-quality or uneven paper, it's important to increase the printing pressure and ensure an even and sufficient ink application. This helps prevent ink-related quality issues during the packaging printing process.
After reading the above, I believe that the issue of ink blooming is no longer something that worries you. For more information, feel free to continue following China Packaging Network!
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