Printed ink color five phenomena can not be underestimated

[Chinese Packaging Network News] First, the characteristics of the printing plate substrate material do not lead to ink blooming during the printing process.

In reality, maintaining consistent packaging printing pressure is crucial for ensuring stable ink quality in packaging prints. 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 or rotary printing machines, copper, zinc-plated, or resin plates are commonly used for packaging printing, and these require a backing board to hold the printing plate in place. This backing board plays a vital role in controlling the printing pressure, so it must be sturdy, firm, and resistant to deformation to ensure consistent ink transfer.

Traditional wooden boards have been widely used as backing materials, but they come with several disadvantages. They tend to wear out quickly, are prone to overprinting, and often result in poor ink transfer. This can cause uneven or insufficient ink coverage on the printed surface, mainly due to the instability and deformability of wood. To prevent such issues, proper padding techniques should be applied. When using a backing board, it’s essential to evenly distribute the padding. For large printing areas, metal die pads—such as magnetic trays or aluminum plates—are recommended. These metal backing boards offer better flatness, strength, and compressive resistance, which help maintain stable printing pressure and reduce ink-related defects.

Second, poor machine condition or improper adjustment can also lead to ink blooming. As machines age, components like roller shafts, bearings, gears, and ink rollers may experience wear and looseness, affecting the stability and uniformity of both the printing pressure and ink distribution. If a large-area print is produced under these conditions, ink blooming is more likely to occur. To avoid this, regular machine maintenance is essential, especially for parts like the embossing unit and ink roller bearings. Ensuring these components remain well-lubricated helps prevent wear and loosening. Additionally, if the ink roller position is misaligned, it can cause uneven contact between the ink roller and the printing plate, leading to ink blooming. Therefore, it's important to adjust the pressure between the ink roller and the impression cylinder to be even and moderate.

Third, improper lining materials can also contribute to ink blooming. The lining acts as an intermediary in transferring ink from the printing plate to the substrate. The material and quality of the lining directly affect the final ink quality. If the lining has a high deformation coefficient or poor flatness, it can lead to ink bleeding or uneven coverage. Therefore, it's important to choose the right lining material based on the specific requirements of the packaging job. For soft resin plates or textured plates, rigid linings such as cardboard, kraft paper, or insulation paper are ideal because they provide good stability and minimal deformation. On the other hand, for hard copper or zinc plates, which have lower gloss and ink affinity, softer materials like cloth, blankets, or offset paper are preferable to reduce ink defects.

Fourth, ink discoloration can occur when using zinc plates for large-area prints. Common causes include oxidation on the plate surface, which creates a "sand-eye" effect, or excessive baking temperature and etching solution levels that reduce the plate’s ability to absorb ink. This results in poor contact between the ink layer and the printed surface, causing ink defects. To resolve this, the plate surface can be gently abraded with charcoal to reduce roughness, and the printing pressure and ink supply should be adjusted accordingly. For fine print packaging jobs, solid resin plates are recommended, as they are softer, have better gloss, and offer improved ink adhesion, reducing the risk of ink blooming and ensuring high-quality prints.

Fifth, the paper itself can also cause ink-related problems. Papers with rough surfaces tend to absorb more ink due to the gaps formed by their fibers. These rough surfaces may not make good 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. Therefore, when printing on papers with poor smoothness, it's advisable to increase the printing pressure and ensure that the ink is evenly distributed and properly absorbed. This helps maintain the quality of the printed ink and avoids common defects.

After reading the above, I believe that the issue of ink blooming is no longer something that should worry you. For more detailed information, feel free to continue following China Packaging Network!