The Problems of UV Flexographic Ink in Printing

Date: Oct 14 2024 From: Star Color

UV flexographic ink may encounter various problems during the printing process, which may stem from multiple aspects such as the ink itself, printing equipment, printing process, or substrate. The following is a detailed analysis of common problems with UV flexographic ink in printing:

1.Ink viscosity issue

1. Excessive viscosity
Phenomenon: Poor ink fluidity, unclear edges of printed patterns, and even wire drawing phenomenon.
Reason: Ink left undisturbed for a long time, or improper storage conditions leading to the precipitation of components in the ink.
Solution: Stir the ink thoroughly to ensure even distribution of components in the ink. If necessary, a suitable amount of diluent can be added to reduce the viscosity of the ink.

2. Low viscosity
Phenomenon: Ink easily penetrates the substrate, causing the color of the printed material to become lighter, and even leading to plate bleeding.
Reason: Excessive addition of diluent or low viscosity of the ink itself.
Solution: Reduce the amount of diluent added appropriately, or replace the ink with a higher viscosity.

2. Ink solidification issue

1. Insufficient curing
Phenomenon: The surface of the printed material is sticky, or the ink layer is not completely cured.
Reason: Insufficient curing time, insufficient power or aging of curing equipment, insufficient curing agent content in ink, etc.
Solution: Extend the curing time, replace the curing equipment with higher power, or replace the ink with more curing agent.

2. Excessive solidification
Phenomenon: Cracks or excessive brittleness appear on the surface of printed materials.
Reason: Long curing time, high power of curing equipment, or excessive addition of curing agent in ink.
Solution: Shorten the curing time, reduce the power of the curing equipment, or replace the ink with less curing agent.

3 Ink adhesion issue

1. Insufficient adhesion
Phenomenon: The ink layer is prone to detachment from the surface of the substrate.
Reason: Poor compatibility between ink and substrate, or improper surface treatment of substrate.
Solution: Choose ink suitable for the substrate, or treat the surface of the substrate appropriately, such as applying base oil, polishing, etc.

4 Ink printing suitability issues

1. Printing pattern defects
Phenomenon: Printing patterns may appear blurry, broken, or missing corners.
Reason: high ink viscosity, insufficient scraper hardness, insufficient screen tension, etc.
Solution: Adjust the ink viscosity, replace the scraper with a higher hardness, or increase the screen tension.

2. Ink dries too quickly
Phenomenon: Ink dries quickly during the printing process, causing the color of the printed material to become lighter or there to be a paste phenomenon.
Reason: UV lamp power is too high, printing speed is too fast, or there is too much desiccant content in the ink.
Solution: Reduce the power of the UV lamp, slow down the printing speed, or replace the ink with less desiccant content.

5 Ink bubble problem

1. Phenomenon: Bubbles appear on the surface of printed materials.
2. Reason: The surface tension of the ink is too high, air is mixed in the ink, or the surface of the substrate is not clean.
3. Solution: Add an appropriate amount of defoamer to the ink to reduce its surface tension; Before printing, ensure that the ink is thoroughly stirred and evenly mixed, and clean the surface of the substrate.

The above are various problems that UV flexographic ink may encounter during the printing process, but these problems can usually be solved by adjusting the ink performance, optimizing the printing process, or replacing the appropriate ink.