Flexo Ink Troubleshooting (4)

6. Fleeting

(I) Performance phenomenon

The images and texts have irregular flashes, and some are halos or feathers. The printed images are not clear and often appear at the trailing edge.

(B) Analysis of the reasons

1. The ink pressure between the anilox roller and the printing plate is not proper.

2. The printing plate ink dries too fast and accumulates in the deep stripes of the printing plate, causing the printed product to have flashes.

3. Large ink viscosity

4. The debris on the printed material is affected by dust on the plate or in the environment.

5. The anilox roller does not match the plate and the ink volume is too large.

6. The surface of the substrate is rough.

7. Repetitive printing plates are not clean enough and plates are worn.

8. Insufficient printing speed. The ink on the plate has dried or semi-dried when transferred to the substrate.

9. Too much or poorly dispersed pigments in the ink.

10. Static electricity causes the ink to flash at the sharp edges of the plate.

11. The plate was damaged during cleaning, and the plate was improperly glued.

12. Plates are not resistant to printing, swelling, and rough prints.

13. The misdirection of printing plates is not conducive to balance and stability of printing pressure. When printing, the force is slightly larger. During rotation, when the pressure is applied, the printing plate rebounds.

14. The embossed (printed shoulder) angle of the plate is too flat and shallow.

(three) solutions

1. Adjust the pressure between the anilox roller and the plate to reduce the occurrence of ink stacking at the edges.

2. Use a suitable solvent to reduce the ink drying speed.

3. Reasonably adjust the ink viscosity and check it regularly.

4. Clean the debris on the printed material. Pay attention to environmental hygiene:

1 The printer is separated and separated from the outside by a curtain. Clean the floor with a damp cleaner every day. The floor is treated with special paint to prevent dusting.

2 Pay attention to the flow of people and dust, and stop high-speed fluids.

3 The daily maintenance of the machine should also pay attention to the cleanliness of the ducts and other unattractive parts to prevent dust accumulation.

5. Depending on the print pattern, change the anilox roller to determine the correct BCM value.

6. Change the substrate with good smoothness.

7. Clean and check the plate.

8. Increase the speed of printing.

9. Add solvent, binder and stir well in the ink.

10. Use anti-static devices.

11. Use adequate cleaning agent to fully detackify.

12. Change version.

13. Change or change the layout.

14. Ask the plate supplier.

Seven, ink color mixing, overprinting is not good

(I) Performance phenomenon

The first color ink is successively transferred to the various printing plates, or the latter color cannot be clearly printed on the previous color.

(B) Analysis of the reasons

1. In multi-color overprinting, the ink of the previous color dries too slowly (in the later colors).

2. The second color ink dries too quickly.

3. After the second color, the viscosity of the ink is too high.

4. Fast, no heat drying box.

(three) the solution

1. The quicker solvent is added to the previous color ink to increase the drying temperature of each printing unit and increase the amount of hot air. Flexo printing is wet-stack dry printing.

2. Add a slow solvent and check the drying unit.

3, increase the printing speed, reduce the ink viscosity of the unit after the second color.

4. As far as possible after each monochromatic overprint, the oven is thoroughly dried.

Eight, ghosting

(I) Performance phenomenon

There are unwanted lines around the printed graphics. The outline of the picture and the edge is obvious, there is a pile of ink phenomenon, the picture is crushed. (The edge of the print is dark and the middle color is light)