It is a common problem that the ink layer on the surface of the self-adhesive label is not dry after printing, which may be caused by a variety of factors. To solve this problem, the following are some solutions and suggestions:
1. Reason analysis
Too thick ink layer: too much ink and too thick ink layer will lead to ink drying difficulties, especially in large area field printing.
Ink type or additive problem: The type of ink used is inappropriate, the additives in the ink are inappropriate or the proportion is too high, can affect the drying performance of the ink.
Machine running too fast: Too fast machine speed may lead to insufficient residence time of ink on the substrate, thus affecting the drying effect.
Insufficient power of the drying device: The power configuration of the UV lamp or infrared hot air drying device is unreasonable or the power is reduced, which will also lead to poor ink drying.
Low surface tension of the substrate: If the surface tension of the substrate is lower than the surface tension of the ink, the ink is not easy to adhere to the material, thus affecting the drying effect.
Second, the solution
Adjust the ink layer thickness:
The method of deep ink thin printing is used to reduce the thickness of the ink layer and ensure that the ink can be fully dried.
In the process design as far as possible to avoid ink overlapping printing, can use the graphic edge parallel color process.
Replacement or use of special ink:
Use special inks that dry quickly, which usually have better drying properties.
If the ink type is not suitable, the ink that matches the substrate material should be replaced in time.
Adjust ink additives:
Ensure that the proportion of ink additives is appropriate to avoid excessive ink dilution and affect drying.
If necessary, photosensitizer (desiccant) is added to the ink to speed up the drying speed.
Adjust the machine speed:
Reduce machine speed and give the ink more time to dry.
If the paper speed is faster, the power of the UV lamp should be increased to ensure the drying effect of the ink.
Check and increase the power of the drying unit:
Check whether the power of the UV lamp or infrared hot air drying device is enough, and replace or increase the power in time when it is insufficient.
Regularly clean the reflector of the UV lamp to reduce the loss of reflected energy.
Increase the surface tension of the substrate:
If the surface tension of the substrate is low, the surface tension value can be increased by methods such as corona treatment to reach more than 38 dyne/cm.
The use of transparent solvent-based inks for pre-priming can also improve the surface tension of the substrate.
Improve the production environment:
Keep the production environment clean and sealed to prevent impurities such as dust and paper scraps from being adsorbed to the surface of the substrate material.
Install static eliminator and substrate cleaner on the press to prevent impurity contamination.
Other measures:
UV glazing is recommended after printing to protect the printing ink layer and increase its adhesion fastness.
For some special materials, such as FASCLEAR and PRIMAX, hardeners can be added to inks and glazing oils to improve friction strength and hardness.
Third, precautions
When solving the problem that the surface ink layer is not dry after the self-adhesive label is printed, various factors should be considered comprehensively and corresponding measures should be taken to solve it.
The properties of different materials and inks may vary, so when selecting materials and inks, they should be fully understood and tested for suitability.
Maintain and check the performance and status of printing equipment and its auxiliary devices (such as drying equipment) regularly to ensure its normal operation and effective work.
Through the above methods and suggestions, it can effectively solve the problem that the ink layer on the surface of the self-adhesive label is not dry after printing, and improve the quality and stability of the printed matter.