In gravure printing, in addition to easy to cause fire, there are a variety of failures, ink and other issues are more common failures, the following Beite packaging to explain one by one.
① Ink overflow: the phenomenon is that the ink full plate part produces spots and patterns, the main reason is that the viscosity of the ink is too low, the fluidity of the ink is too large, the printing speed is low, the ink drying is too slow or there is static electricity. The elimination method is to add the original ink and adjusting agent to improve the ink viscosity, reduce the fluidity, also can increase the printing speed or change the angle of the doctor blade.
② Ink in the pattern of drying and buried plate: ink drying speed is too fast, resulting in ink drying in the pattern. There are many reasons for the embedded plate, such as large ink pigment particles, foreign matter mixing, poor re solubility of ink fixing agent, high ink viscosity, shallow ink hole, etc. The elimination method is to reduce the drying speed of ink, increase the solvent amount of ink, improve the re solubility of ink, remove foreign matters and reduce the viscosity of ink. At the same time, the hot air of drying device should be prevented from blowing to the layout, causing the ink drying in the pattern.
③ Blind paste fuzzing: it is mainly caused by static electricity. It is necessary to remove the static electricity of the substrate and ink, improve the humidity of the substrate, or add polar solvent and modifier to the ink to improve the viscosity of the ink and appropriately increase the printing speed.
④ Poor gloss of printed matter: adding appropriate amount of raw ink can also appropriately improve the drying speed of ink and replace high-quality printing materials.
⑤ Poor overprint: the ink film of the first printing ink has ink discharge property, which is caused by the viscosity mismatch of each ink and the drying speed of the ink for lamination. Can reduce the viscosity of ink, slow down the drying speed of overlapping ink.
⑥ Reverse printing and ink stacking: ink is stuck on the reverse side of printed matter due to stacking. The causes are that the solvent in the ink contains a small amount of high boiling point components, which causes the solvent evaporation rate to be too slow, too much plasticizer and plastic resin in the ink, poor drying device, too deep ink hole on the printing plate, and excessive relative humidity in the printing workshop. The method of exclusion is to select the resin with good solvent separation, reduce the content of plasticizer and plastic resin in the ink, properly add anti printing inhibitor, and try to use the solvent with narrow boiling point range in the ink. Improve the drying device and improve the drying efficiency. Use the cylinder with shallow ink hole and improve the environmental conditions.
⑦ Scratch: the main causes of scratches on printed matter are damage of the doctor blade, improper pressure of the blade, incorrect angle of the blade, foreign matter mixed in the ink, high viscosity of the ink, strong adhesion of the ink, coarseness of the pigment particles, scratch, uneven concave and convex of the printing plate cylinder, poor correction, etc. The way to eliminate this problem is to use the ink without foreign matters, filter the residual ink before using, adjust the viscosity, dryness and adhesion of the ink, use a high-quality scraper, adjust the pressure and angle of the scraper, and correct the plate cylinder.
Ink hydration: the moisture in the air enters the ink, resulting in sticking, precipitation of resins, gelatinization and other phenomena, resulting in ink gloss reduction, concentration reduction, poor transfer, easy to paste, and other ills. In order to avoid hydration, it is better not to use too fast drying solvent, and reduce the contact between ink and air.
Albinism: the ink transferred to the surface of plastic film is seriously misaligned due to the serious volatilization of solvents. The phenomenon of "resin albinism" of resin insoluble, cloudy and partially gelatinization occurs. In order to prevent whitening, the printing speed can be increased, or the drying oven is close to it, or the drying solvent is used to slow down the drying speed of the ink.
(manufacturer of antistatic aluminum foil bag, fruit bag, daily chemical packaging bag, packaging roll film manufacturer of Beite (China) packaging Co., Ltd.)