Corrugated cardboard paper printing doubt (2)

2. Ink-related printing failures (1) Improper ink viscosity. Ink viscosity is too low, easy to paste version when printing, and the amount of water must also increase, in the transmission of the water roller will also stick the ink back on the plate cylinder, so that the dampening fluid dirty. In addition, after the printed matter absorbs a large amount of moisture, it will be deformed and bent, making it difficult for post-press processing. In addition, inks with lower viscosity and cohesive force can also exhibit centrifugal flying ink during high-speed printing. If they fly onto the printing plate, they are stuck back by the water roller, causing the dampening solution to be dirty, which in turn can cause paste printing. The viscosity of the ink is too high and the ink is difficult to print. In particular, the mesh adjustment cannot be printed. Even if the ink volume is increased, the effect is not obvious, and the print is prone to blocking.

(2) Prints are easy to fade. High-brightness and wear-resistant inks are used in the printing of corrugated cardboard face sheets to ensure that the printed pattern can withstand frequent handling and friction during transportation. Do not mix gasoline when adjusting the ink, because gasoline will dissolve or crack the cohesive crosslinked material in the ink, breaking the chain structure of the binder. The varnish can not be added too much, otherwise the binder resin in the ink will be diluted and separated from the pigment, so that the pigment is suspended in the powder on the surface of the paper, and the grease and its dissolved auxiliary agent are absorbed by the paper fiber. To the inside of the paper, if such a printed matter is directly attached to the corrugated medium, scratches or discoloration will occur easily in the production; if the film is laminated, blistering and floating phenomenon will occur, and the film will be easily peeled off; if it is glazing, it will be easily discolored and generated. Scratches; If calendered, varnish and pigments are easily peeled off by the tape.

(3) The print is too dry. This has a lot to do with the Flexo Printing Exposure Machine ink transfer. When printing large areas on the ground, if there are too many lipids in the ink, the lipophilicity of the paper fibers will affect the drying of the auxiliary. In addition, a large area after printing often requires glazing, which is more detrimental to ink drying. In addition, in the high-temperature drying season can not be excessive use of dry oil, anti-sticking agent can be used instead of part of the dry oil, and increase the amount of dusting, to prevent adhesion, which may cause trouble to the subsequent coating process, but the film Temporary increase in the powder removal process.

3. Paper-related printing failures

The quality of the opposite paper must be strictly controlled, and the strength, tightness, elongation, flatness, glossiness, whiteness, etc. of the paper should be inspected at the time of entering the factory and ensure compliance with the requirements.

The color of the facial paper will affect the printing effect of the main body color. The evenness of the coating of the facial tissue and the flatness of the press coating also have a great influence on the halftone printing, which may easily cause inconsistency in the hue of the flat screen printing, especially the 3-60% of the web. The most sensitive tone.

Deformed paper can cause wrinkling when it is printed. The humidity in the shop should be adjusted to restore the moisture content of the paper. Curved paper is difficult to feed. It is necessary to adjust the volume of loose paper blowing nozzles and nozzles according to the degree of bending of the paper, and to increase the strength of the paper feeding pulley to ensure that the paper is fed well. When printing, it should be noted that the fiber direction of the tissue Flexo Printing Solutions should be perpendicular to the direction of the corrugation when the box is formed. For products that need to be printed twice, the paper should be loosened on time after printing, and then tightly packed after the initial drying to prevent the paper from being deformed and affecting overprinting.

For powdered paper, the Flexo Printing Solutions viscosity of the ink can be properly reduced or the printing pressure can be appropriately reduced to make up for it, and the layout with the least number of patterns should be arranged in the first color group so that the paper powder and paper hair can be stained when printing the first color. , And the printing speed should not be too fast, but also wash the blanket. For some papers that have lost powder and have more severe hair loss, the use of prepress air pressure or preprinting of a layer of anti-sticking agent (plus a small amount of white ink) may solve the problem to some extent, but in materials, energy, time, etc. The consumption will undoubtedly increase the cost, and there will still be various problems in the post-press processing.

Issues related to post-press processing

The quality of post-press processing depends on the quality of the print. The printed matter can be fully dried and flush, without deformation and bending, and the quality of the postpress processing can be guaranteed.

For products that require hot stamping, the positioning during printing should be accurate, otherwise the hot stamping displacement phenomenon is likely to occur.

Foaming, wrinkling, and darkening are common problems in the film. The poor drying of the printed ink will cause foaming of the film, as the organic solvents and moisture in the ink will vaporize after hot rolling and are just sealed by the film, especially when the film speed is too fast. Some facial tissues are wrinkled, and the facial tissue is not neat or curved. When it is covered, it will cause tearing and wrinkling. In addition, the wear of the laminator's silicone rubber pressure roller can also cause wrinkling of the film. The moisture content of the paper is large and it becomes dark after lamination. For printing gold products, if the moisture content of the paper is too high, the moisture content of the Flexo Printing Plate Washing Machine coated film will be more difficult to evaporate, which will cause oxidation and darkening of the gold ink.

The brightness of finished products when calendered depends mainly on four aspects: one is the gloss and flatness of the paper; the other is the amount of oil. The amount of oil is too little, the light brightness after calendering is poor, but the amount of oil is too much. After the calendering, the prints are yellow and dark; the third is the drying time of the varnish. Varnish drying time can not be too long, otherwise the pressure is not smooth after drying, or pressure is not light, but the light oil drying time is too short, the varnish solvent is not dry, after the pressure is lightened by the steel tape, the printed matter will be exposed, After exposing the flowers, they will stick together after being stacked together; Fourth, the old and new steel strips. The effect of the new strip calendering is better than that of the old strip.