Ink Printing Failure Analysis and Troubleshooting

1. Picture crushing

main reason:

1) caused by the printing process itself;
2) The printing pressure is too large;
3) Ink viscosity is too high;
4) Ink mixing is uneven.

Remedy:

1) Pad version and adjust the level of printing balance;
2) Adjust printing pressure;
3) adjust the ink viscosity or change to low viscosity ink;
4) Reasonably mix ink.

2. Graphically blurred

main reason:

1) Platemaking problems, bad quality of the printing plate;
2) Large ink viscosity;
3) Dispersion of ink pigments is not good;
4) The plate and ink roller are in tight contact.

Remedy:

1) Printing plates should be smooth and clean;
2) Adjust the viscosity of the ink and control it in 25 ~ 35s / coated 4 # cup;
3) Fully stir the ink;
4) Adjust printing pressure.

3. Insufficient ink transfer

main reason:

1) Insufficient printing pressure;
2) The hardness of the flexographic plate is not enough or the anilox roller is clogged; the gravure web is too deep;
3) The water content of the paper is too large;
4) Ink roller wear and aging;
5) Poor ink flow.

Remedy:

1) increase the printing pressure;
2) Check whether the flexographic plate hardness is in the range of SH42±3, replace the flexible flexographic plate or eliminate moire; clean up the blockage in the roll and intaglio, and replace the intaglio plate (requiring engraving depth of 25 to 45 μm).
3) Use more hydrophobic ink;
4) Clean the dry spots on the plate, and pay attention to the surface treatment of gravure rust.

4. Insufficient ink film resistance

main reason:

1) The resistance of the ink itself, such as poor water resistance and light resistance;
2) The film-forming resin in the ink is poor in quality or insufficient in content.

Remedy:

1) Replace the new ink or make up the resin solution (the pH is controlled between 8 and 9.3);
2) Replace lightfast ink or add UV absorbers to the ink;
3) Add an appropriate amount of ink (such as acrylic or add calcium salt).

5. Ink film has pinholes

main reason:

A. Chemical pinholes, characterized by different pinhole locations, sizes, and numbers.
1) Insufficient or excessive defoamer;
2) Ink dilute;
3) Too much ink with low viscosity.

B. Mechanical pinholes, characterized in that pinholes often appear in the same site, and pinholes with the same size and quantity reappear.
1) rough layout;
2) The ink roller is defective or distracting.

Remedy:

A. Chemical pinholes:
1) Add an appropriate amount of defoamer;
2) Incorporation of original ink;

B. Mechanical pinholes:
1) The printing machine air-printing run-in or replace the printing plate;
2) Correct the ink roller and adjust the printing pressure.

6. Ink blisters

main reason:

1) Insufficient or excessive defoamer dosage;
2) Ink dilute;
3) Too much ink with low viscosity; Defoamer has quality problems; Insufficient ink circulation or ink tube leak.

Remedy:

1) Defoamer should be controlled at about 0.2%;
2) increase the circulation of ink;
3) Replace the pipe or repair the damage;
The ink is best stored for 48 hours and then used on the machine (after the foam disappears and stabilizes).

7. Ink gelation

main reason:

1) Use wrong solvent;
2) Mix with different inks;
3) Bad storage environment;
4) The ink deteriorates over time.

Remedy:

1) Use a good solvent, can add the appropriate amount of cosolvent (ethylene glycol, glycol ethers);
2) Use the same performance, the same brand of ink deployment spot color ink;
3) Accurate measurement when adjusting ink;
4) The ink should be sealed at any time after use, and stored in a ventilated and dry place;
5) Replace the ink (add TM-3 or inorganic salt anti-gelatin in the ink).

8. Plate wear

main reason:

1) roller contact is too tight;
2) The ink is mixed with coarse particles;
3) paper or dust into the ink or ink fountain;
4) Printing pressure is too large;
5) The quality of the printing plate is poor.

Remedy:

1) Re-adjust the roller contact gap;
2) filter ink;
3) regular cleaning ink fountain;
4) Adjust printing pressure;
5) Replace the plate.

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