In gravure printing, uneven ink film thickness occurs from time to time. There are many reasons for uneven ink. In the case of gravure ink, it is poor ink blending, or the ink is accidentally mixed into the ink when the ink is blended. At this time, due to the addition of solvent, the ink swells or softens, blocking the mesh holes that should be ink-permeable, causing the effect of the plate film, making the ink unable to pass normally.
In order to prevent this kind of failure, the gravure ink (especially the old ink) after blending should be filtered once with a net before use. When reusing a used printing plate, the old ink attached to the plate frame must be completely removed. When storing the printing plate after printing, wash it sufficiently (including the squeegee). If you follow the above requirements, the uneven ink will not happen.
If the tip of the front end of the scraper is damaged, there will be traces along the direction of movement of the scraper. Especially when printing transparent materials, obvious ink unevenness will appear. Therefore, the front end of the scraper must be well protected so that it will not be damaged. If it is damaged, it must be carefully polished with a grinder.
The unevenness of the printing table will also affect the uniformity of the ink. The convex ink layer is thin, and the concave ink layer is thick. This phenomenon is also called uneven inking of gravure ink. In addition, if there is dust on the back of the substrate or on the printing table, the above-mentioned failures may also occur.