The failures in gravure printing are mainly caused by printing plates, inks, substrates, doctor blades, etc.
(1) The phenomenon of periodic ink color changes on printed products with uneven ink density. The elimination methods are: correct the roundness of the plate cylinder, adjust the angle and pressure of the doctor blade, or replace with a new doctor blade.
(B) Blotting and blushing The printed images are graded and blurred, and burrs appear on the edges of the graphics. Exclusion methods include: removing static electricity on the surface of the substrate, adding polar solvent to the ink, appropriately increasing the printing pressure, adjusting the position of the squeegee, etc.
(3) The phenomenon that the blocking ink dries in the holes of the printing plate or the holes of the printing plate are filled with paper wool and paper powder is called blocking. Exclusion methods include: increasing the content of solvent in the ink, reducing the speed of ink drying, and printing on paper with high surface strength.
(4) The phenomenon of ink spotting on the solid part of the printed matter. The methods of elimination are: add hard ink to increase the viscosity of the ink. Adjust the angle of the squeegee, increase the printing speed, and replace the deep mesh printing plate with a shallow mesh printing plate.
(5) Scratch marks are on the printed matter. The methods of elimination are: printing with clean ink without foreign matter mixing. Adjust the viscosity, dryness and adhesion of the ink. Use a high-quality doctor blade to adjust the angle between the doctor blade and the printing plate.
(6) The phenomenon that the color of the pigment deposit on the printed matter becomes lighter. The elimination methods are: printing with ink with good dispersion and stable performance. Add anti-agglomeration and anti-settling additives to the ink. Fully rolling and often stirring the ink in the ink tank.
(7) The phenomenon of ink stain on sticky printed materials. The elimination methods are: choose ink printing with fast volatilization speed, increase the drying temperature or reduce the printing speed appropriately.
(8) Ink peeling The ink printed on the plastic film has poor adhesion, and is rubbed off by hand or mechanical force. The exclusion methods are: to prevent the plastic film from being damp, choose ink with good affinity to the plastic film for printing, and re-surface treatment of the plastic film to increase the surface tension.
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