Intaglio plastic ink common printing troubles and solutions

First, reverse adhesion:
Phenomenon: After the ink is printed, the printed product will stick to the back of the printed substrate, and the pattern will be destroyed, which will usually cause the product to be scrapped. This phenomenon is called reverse adhesion.
Reasons: (1) poor drying; (2) high pressure during rewinding; (3) excessive temperature during rewinding; (4) electrostatic charging of film; (5) residual solvent.
Solution: (1) Touch the pattern of the print to see if it is not dry, replace the faster-drying solvent if the print is not dry, and speed up the drying of the ink. If the surface of the ink is dry, but not completely dried, adjust the proportion of the solvent, reduce the amount of fast-drying solvent, increase the amount of slow-drying solvent, and increase the hot air temperature. Make sure the ink is completely dry before rewinding. (2) See if the pressure on the rewinding is too large, if the film is deformed during rewinding, and appropriately reduce the pressure during rewinding, the printed product shall be placed upright after rewinding, and the printed product shall not be put down and pressed to the printing part; (3) To see if the temperature of the film is returned to normal temperature, if the film is still warm during winding, let the printing machine's drying system blow cold air before winding to ensure that the film returns to normal temperature before winding; (4) Touch the printing surface of the film with your hand to see if the film is seriously charged with static electricity. If you have static electricity, you need to check the ground of the printing press to ensure that the ground wire is connected; (5) If the ink is dry, press the large printing surface with your hand. To see if the print is sticky, if the sticky hand is a residual solvent, adjust the solvent used and its ratio.
Second, printed products appear "water spray point"
Phenomenon: After the ink is printed, the printed product appears to be a lot of water spots, or a fine-grained water mark. The pattern is not full and realistic.
Reason: When the ink is printed on the machine, the speed is slower and the ink is too thin.
Solution: Increase the speed of printing; or add original ink to increase the upper machine's viscosity.
Third, the printing plate clogging phenomenon: ink printing, found that there will be a lot of print products, but not water-like. Instead, there are many occurrences of dry spots.
Reason: This is because the printing speed is not high, and the ink drying is too fast, causing the gravure network to be blocked.
Solution: Use a thinner to wipe clean the print gravure first, then increase the printing speed to print, or add a slower dry diluent to slow the drying speed.
Fourth, the phenomenon of print whitening: After printing found that the surface of the printing layer of a white layer of fog, resulting in the printing effect is not obvious, not realistic, called the phenomenon of whitening, or called white, white.
Cause: The cause of whitening is mainly due to the environment's high humidity or unbalanced true and false solvents.
Solution: Reduce the humidity of the environment; enhance the drying of the hot air; use a slow-drying solvent and add a true solvent with a higher boiling point.
Fifth, the phenomenon of biting color: When doing the overprinting; the latter ink will stick to the color of the previous printing, which will cause the ink in the ink tank to gradually change color.
Cause: The previous process blot was not completely dried; the pressure was too great for the next print.
Solution: Increase the speed of the previous ink drying, increase the temperature of the hot air and the amount of air supply, ensure that the printed product is dry until the next time; reduce the pressure of the printing and reduce the viscosity of the ink.
Sixth, the phenomenon of solvent analysis: In the printing ink on the machine, after adding the solvent found that the ink particles precipitated, no stickiness, or no mobility.
Cause: The ink was not properly selected and was not stirred well when the solvent was added.
Solution: Contact the ink manufacturer to use the correct diluent to dilute the ink. When diluting the ink, do not add the solvent one by one. Mix the solvent first and then add it to the ink (if necessary, add it while stirring). After adding the solvent, stir it evenly.
Seven, bad printing fastness: Ink printed on plastic film, with adhesive tape peeling test prints easily stick.
Causes: poor corona treatment of polyolefin film; poor affinity of the ink and the printed material; incorrect ratio of the mixed solvent; large variation in relative humidity of the printing shop; poor printability of the plastic film itself, and unsatisfactory after corona treatment .
Solution: Check whether the surface tension of the plastic film reaches 40 dynes/cm2 or more; adjust the solvent ratio or replace the ink; try to control the humidity of the printing shop between 50-60%, but not too low, or it will easily generate static electricity. The room temperature is preferably controlled between 18-23°C, and the environment is kept clean, the air circulates, and the used printed materials are replaced.