UVLED screen printing ink
The composition of UVLED screen printing ink is mainly composed of pigment particles, resins, solvents and modifiers. Although the main role of pigment particles is only to display color, the size and dispersion degree of particles will have a certain impact on the rheological properties of the ink. The main role of modifiers is to improve certain rheological properties of UVLED inks.
Screen printing UV LED ink is printed to the object by extruding through a layer of nylon cloth with graphics (holes), and the UVLED ink is printed to the object through the small holes in the cloth to form an image. The number of holes per square inch determines the quality of the print and also affects the rheological properties of the ink. Before printing, the UVLED ink is tiled on the screen and cannot drip through the mesh. This requires the ink to have a high viscosity under low shear force and not flow under gravity. When used, when the roller presses through the mesh, the ink is squeezed through the mesh.
UVLED ink must be sheared and thinned under the action of external force, and under the action of revoking external force, it can quickly restore the original structure, and high viscosity, and the ink will drip through the mesh. When the roller passes through the mesh and presses the mesh against the print, the UVLED ink is distributed to the object in the form of ink dots according to the distribution of the holes on the mesh. At this time, the length of time for the structure recovery of the UVLED ink is critical, too short, the UVLED ink will cause shortcomings, too long, it will cause scattering. Both of these conditions cause a decrease in image sharpness.
UVLED screen printing light source has a long service life and low power consumption, especially in the case of flexo printing and sheetfed printing, and the printing plant can save almost 50% of the electricity bill.
UVLED screen printing has the characteristics of thick ink layer, rich graphic layer, strong three-dimensional sense, wide printing materials, etc., and the application of high-grade tobacco and alcohol, food packaging cartons has gradually increased. Printing frosted, refractive, ice flowers, wrinkles and other effects on cigarette packs greatly stimulates consumers' desire to buy. However, due to the low printing speed, slow ink curing speed, difficult control of printing quality, and large consumption of printing materials, it is impossible to meet the needs of cigarette carton scale and mass production. The use of high-speed rotary screen printing production line, fast printing speed, high productivity, stable print quality, low consumption, changed the traditional flat flat screen printing, manual paper feeding, ink supply mode, suitable for high-speed automatic and large-scale mass production of exquisite folding cartons.
Web web rotary UVLED screen printing uses nickel metal round screen printing plates, built-in squeegee and an automatic ink supply system that transfers the printing ink from the round screen plate to the substrate surface supported by the imprint cylinder. The whole printing process from paper feeding, ink supply, printing color registration, UV dry bath, etc. are fully automatic control by computer. The round UVLED screen printing plate adopts 100% nickel non-woven fabric material, electroformed and its mesh is hexagonal filament-shaped holes, and the whole mesh surface is flat and uniform to ensure the stability and precision of the imprint. Suitable for large-format rotary printing, the maximum speed can reach 125m/min, and the screen can be reused 15 times. Therefore, web rotary UVLED screen printing can not only meet the requirements of special effects such as printing frosting, ice flowers, etc., but also can hot stamp holographic anti-counterfeiting logo, embossing, die-cutting molding, easy to achieve high-speed automatic printing of cartons.
