Flexo Ink Troubleshooting (6)

(three) solutions

1. Add fresh ink to improve ink adhesion and ink color intensity.

2. Clean the plate: Use a chronic desiccant and consider the ink provided by the supplier.

3. Check the ink formulation, check the ink for deterioration, and check the handling of the raw materials.

4. Adjust pressure.

5. Check version.

6. Replace the mesh roller and ink roller.

7. Replace the substrate.

8. Add slow drying agent.

9. Check for ink replacement.

10. Reduce the squeegee pressure.

Ten, ink foaming

(I) Performance phenomenon

The surface of the ink in the ink fountain is covered with a layer of air bubbles, and the ink is liable to splash when printing.

(B) Analysis of the reasons

1. Printing speed is too fast.

2. Add too much, high hardness tap water, ink solvent surface tension range.

3. Big difference in air pressure.

4. The viscosity of the ink is large and air pressure cannot be released.

5. Excessive circulation stirring.

6. A pH of less than 8.5 can cause blistering.

(three) solutions

1. Reduce printing speed.

2. Add defoamer or alcohol solution to improve the surface tension. Anti-foaming agent is mainly to eliminate air bubbles in the ink. Generally, 0.5%-1% of the total amount is added to the ink before starting printing or during printing. It is best to spray evenly with a small sprayer.

3. To relieve pressure.

4. Reduce viscosity.

5. Reduce circulation stirring.

6. Adjustment.

Eleven, viscosity increase

(I) Performance phenomenon

The viscosity of the ink increases during use and the color deepens.

(B) Analysis of the reasons

1. Due to the volatilization of ammonia in the ink.

2. Workshop temperature changes.

(three) solutions

1. Appropriate stabilizers are added during the printing process to control the viscosity of the ink and ensure that the hue is consistent before and after (measured on the machine with the Zahn cup). The viscosity is related to the pH value, the ink keeps circulating, the pH value of the ammonia water volatilizes, the viscosity increases, and the water volatilizes, making the color deeper. Always maintain viscosity stability during printing. No matter in the prepress or in the printing process, the pH value of the ink should be measured to be stable at about 9 under conditional conditions, and the ink has the proper viscosity only under reasonable alkaline conditions, so as to ensure that Good liquidity. Sometimes before printing or printing, the viscosity of the ink is large and the pH value is appropriate. This is mainly due to the poor thixotropy of the ink. At this time, it is not necessary to add additives to adjust, just use the ink shovel to stir for a while, the viscosity of the ink. It will reduce and regain good liquidity.

2. Keep it at constant temperature and humidity.