4. Bad ink fastness
Insufficient printing ink fastness, especially in printed matter with poor printing fastness on the plastic surface, the ink is easy to fall off during the packaging and distribution process. If the ink is detached at the bar code, it will affect the reading.
the reason:
(1) Insufficient resin, such as printing ink, or poor adhesion of the resin itself.
(2) ink is too thin;
(3) The solvent loses its balance and the ink deteriorates;
(4) misuse of ink or mixing of different types of ink;
(5) The corona treatment on the surface of the printing film is not enough or the influence of additives in the film;
(6) Improper control of process conditions such as ink drying.
Solution:
(1) Adding gold oil, etc. to increase the resin composition;
(2) Printing as high as possible;
(3) Replace ink;
(4) Use high quality printed substrate film;
(5) Adjust the process conditions.
5. Reverse printing
During overprinting, the first color of ink is reverse printed onto the second color plate and transferred to the film.
the reason:
(1) This is mainly due to the insufficient drying of the bottom corner (first color) or the relatively fast drying speed of the next color (second color), resulting in excessive tackiness at the moment of printing.
(2) This is also the case when the ink of adjacent colors is poor in compatibility.
Solution:
(1) Reduce the pressure of the roller
(2) Hair to the second color layout
(3) Improve the initial adhesion of the first color and increase the drying speed (use a quick-drying solvent).
(4) Reduce the viscosity of the second color.
(5) Accelerate the drying speed of the first color ink, and strengthen heating and drying. Slow down the drying speed of the second color.
(6) Change the thinner of the second color to the ingredient that does not dissolve the first color.
(7) Replace the ink.
(to be continued)
