Flexo Ink Troubleshooting (1)

First, the ink adhesion is poor (fastness of the poor)

(I) Performance phenomenon

Adhesion of ink and printed material is poor; ink adhesion fails.

(B) Analysis of the reasons

1. Inappropriate ink formulations have poor adaptability to quality of the materials used or expired; the initial dryness of the ink is acceptable, but the dryness after the oven is not acceptable, so the adhesion is poor.

2. The ink layer is too thin and the adhesive is destroyed.

3. Insufficient heating, slow print drying.

4. When the ink layer is overprinted, the ink layer is not completely dried and is covered with a new ink layer to form a false dry.

5. The surface of the substrate is soiled (oil stains).

6. The printing ink layer is too thick, the ink volume is too large, and the viscosity is too large, resulting in embrittlement after the ink is dried for a long time.

7. The surface tension of the substrate is lower than the ink tension.

8. After water-based ink printing, there is no protective layer (such as gold ink).

9. Too much solvent is added to the ink to reduce the content of synthetic resin and to a certain extent the conjunctiva is poor.

(three) the solution

1. Make sure to use the right printing inks on the right materials, and choose different water-based inks for different substrates;

2. Readjust the viscosity of the ink and add fresh ink.

3. Increase the amount of heat and air supply.

4. The ink is dried and then printed with secondary ink to increase the drying power.

5. Oil must be treated.

6. The ink layer should be as thin as possible under reasonable conditions, and the amount should be small. If necessary, it can be overprinted in multiple colors.

7. Can be pre-bottomed to improve the substrate surface tension. The greater the difference between the surface tension value (small) of the ink and the tension value (large) of the substrate, the better the printability of the printing substrate.

8. UV varnish after printing for protection.

9. Add some synthetic resin or special diluent when adding the solvent.

Second, the ink sticks into a block

(I) Performance phenomenon

The ink between the two surfaces adheres to each other into a block, contaminating the back and filthy.

(B) Analysis of the reasons

1. Improper use of solvents.

2. The roll has too much force (pressure) during the receiving process.

3. When rewinding, the surface moisture is high.

4. Received in the hot state, the temperature is too high.

5. Store room temperature is too high.

6. Too thick and too much ink is not dry.

7. Drying system capacity is insufficient.

8. Insufficient drying and drying of the ink, excessive speed.

9. The amount of ink on the substrate is not the right choice and the amount of ink is too high.

10. Local damage to the ceramic roller increases the amount of ink.

(three) solutions

1. Use a complete drying system or balance solvent.

2. Reduce the reeling (pressure) force, and the reel should not be too large and stacking too high.

3. Prevent moisture from entering the rewound area, especially condensed water caused by water-cooled rollers.

4. Cool the print before receiving (with cooling roller or air-cooled).

5. Printed products are placed in a cool place.

6. Reduce the amount of ink transferred (under the condition of satisfying printing).

7. Adjust the drying system.

8. Use appropriate solvents to balance or use low-boiling solvents to increase drying speed; reduce printing speed and increase ventilation heat.