What are the common faults and solutions in the printing process of self-adhesive labels?

The common faults and solutions in the printing process of self-adhesive labels mainly include the following aspects:

First, the ink layer on the surface of the printed label is not dry, dry slowly or the ink layer is wiped away

Cause of failure:

The printing ink layer is too thick and the amount of ink is too large.

The additives used in the ink are not suitable, the ink degeneration or the type of ink used is not suitable.

The machine runs too fast, resulting in insufficient ink drying time.

The surface tension of the substrate is lower than the surface tension of the ink, and the ink is not easy to adhere.

The drying device (UV or infrared hot air drying) has low power, and the ink cannot be completely dried.

The solution:

Reduce the thickness of the ink layer: The use of deep ink thin printing method to reduce the thickness of the ink layer, which is conducive to the drying of the ink.

Choose the right ink: Use a special ink that dries quickly to ensure the drying performance of the ink.

Add supporting desiccant: Use supporting additives, add supporting desiccant, accelerate the drying process of ink.

Extend drying time: Measures are taken to extend the drying or curing time of printed matter to ensure that the ink is fully dry.

Increase room temperature and exhaust air: Increase room temperature, exhaust air, speed up ink drying speed.

Improve the surface tension of the substrate material: ensure that the surface tension value of the substrate material reaches 38 dyne /cm or more, which can be improved by corona treatment and other ways.

Optimize the drying device: increase the drying or curing power, or reduce the running speed of the machine, increase the drying time to ensure that the ink is completely dry.

Second, the ink adhesion fastness is poor, easy to drop ink

Cause of failure:

The surface tension of the substrate is low, and the ink is not easy to adhere.

The characteristics of the ink and the substrate material do not match, or the use of expired, invalid ink.

Printing ink layer is too thick, ink drying is insufficient.

The solution:

Improve the surface tension of the substrate material: ensure that the surface tension value of the substrate material meets the requirements, and improve the surface tension by corona treatment.

Select special inks: Select special inks that match the printing material to ensure the adhesion of the ink.

Optimize the printing process: the printing ink layer should be as thin as possible, the amount of ink should be as small as possible, and multiple monochrome overprinting can be done if necessary.

Strengthen drying and curing: improve the drying or curing power to ensure that the ink is fully dry and curing.

UV glazing protection: UV glazing treatment is recommended after printing to protect the printing ink layer and increase the adhesion fastness of the ink layer.

Third, the fisheye phenomenon

Cause of failure:

Fish eyes are caused by impurities such as paper wool, paper scraps or dust, and are related to the cleanliness of the environment, static electricity, and the quality of the substrate material.

The solution:

Improve the production environment: conditional printing manufacturers should seal the printing press management, improve and purify the production environment.

Install cleaning equipment: Install static eliminator and substrate cleaner on the press to prevent dust and paper scraps from remaining on the surface of the substrate.

Selection of high quality substrate materials: Select substrate materials with high surface coating firmness to reduce the drop of paper scraps.

Improve the cutting quality: improve the cutting quality of the drum material to prevent debris on the end face or around the material.

Regular cleaning equipment: regularly clean the ink delivery system of the printing plate and printing press to keep the equipment clean.

Fourth, the phenomenon of dropping powder

Cause of failure:

The paper itself is of poor quality and the surface coating is of low firmness.

The moisture in the environment or the material itself causes the coating surface strength to decrease.

The ink viscosity is too high.

The solution:

Selection of high-quality substrate materials: especially when large-area field printing, paper with high surface coating firmness should be selected.

Reduce the viscosity of the ink: the viscosity of the printing ink used in the color sequence is required to decrease in turn.

Improve the storage environment: improve the storage and printing environment of materials and reduce the ambient humidity.

Optimize the printing process: change the field printing to flat screen printing in the process design to reduce ink accumulation.

In summary, the common faults and solutions in the printing process of self-adhesive labels involve many aspects, including ink dryness, adhesion fastness, cleanliness and material quality. By taking targeted measures, these problems can be effectively solved and the printing quality and production efficiency can be improved.