4. Ink splash
In the printing shop there are ink dots or ink droplets of different sizes. The ink has a large yield value, high viscosity, ink layer thickness and ink film separation is too long or ink is too thin, the printing speed is too fast, the ink viscosity is too small and does not antistatic, poor precision of the printing press, ink roller deformation or surface Damage can cause ink splashes.
Solution: Replace the ink roller, reduce the viscosity of the ink and reduce the drawing length and fluidity, reduce the supply, high-speed ink viscosity, slow down the printing speed, adjust the temperature and humidity of the workshop, replace the ink roller and repair equipment or add antistatic facilities And materials.
5. Plate, ink roller sticky and scratches
Plates and rollers are stained by ink on the printed material; ink is too small and has a high viscosity; impurities in the ink; ink drying is too fast or too slow; plating on the plates and rollers is worn, hardness is not enough, or The pattern is too deep, and dust such as paper and plastic increases.
Solution: Replace the double-sided tape, adjust the pressure, adjust the angle between the blade and the roller, reduce the amount of ink or replace the ink, increase the speed of the oil, repair the version and roller, re-glazing chrome, prevent paper, plastic and other powder dust Fall off.
6. Poor adhesion and smearing
Printed products are easily wiped off. The surfaces of paper and plastic materials are too smooth and dense. Slow-drying inks should not be used. Insufficient ink resin content, poor surface treatment, and temporary dryness and floating on the surface of printing materials are easily wipe.
Solution: Improve ink type, adjust ink suitability, process printing materials, use ink with high viscosity and high ink density, increase printing pressure, reduce thickness of ink film, reduce printing speed, and use high-efficiency additives and viscosity-increasing inks. Replace the solvents or oils that affect the dryness of the ink, and change the ink oil or dilution ink according to the ink's suitability.
7. Residual irritating odor
The proportion of methanol in the ink is too large and is accompanied by odoriferous solvents or oils.
Solution: Use as little ink as possible or do not use solvents or oils that are irritating or harmful to human health. Replace inks or replace solvents and oils.
8. Inaccurate shades and ink deposits
The color becomes lighter and discolored, producing a paste plate, the quality does not match the sample, the affinity of the pigment, the filler and the binder is poor, and the storage is coagulated or severely stratified. This is because the stirring was not sufficient before use.
Solution: In the storage period, the ink should be stored in a cool, dry and cool place. The color tone should be adjusted as close to the hue of the sample as possible. You can also add 1%-3% white ink to the ink, or increase the filler to increase the coverage. force.
9. Pinhole and skid
Chemical pinholes and mechanical pinholes appear in printed images; spotting occurs in full-page printing, ink overflows during the printing process and large amounts of foam appear.
Solution: When the viscosity of the ink is too low, the proportion of new ink or resin must be changed to increase the viscosity, increase the flowability, increase the printing speed, and add a clouding agent and a plasticized defoamer when the foam appears, and eliminate the foam. For shallow patterns, 25-30um is appropriate.
10. Embedded plate and orange peel
Ink viscosity, many impurities, fast drying, solubility is not balanced, ink is not level, resulting in water lines and orange peel appearance, ink residue and dry knot in the print pit, poor printing gloss, too light, thixotropy leveling Poor performance due to poor affinity between the plate cylinder and paper, plastics, etc., auxiliaries are not suitable for slow printing speeds and electrostatic effects.
Solution: The printing speed is adjusted to: high speed is about 0.012 seconds, medium speed is about 0.055 seconds, low speed is 0.09 seconds, single sheet is 0.012 seconds; hot air or cold wind blowing angle is 90 degrees, direct blowing or improved ventilation, additives Solvent to achieve solubility of solvents or oils and inks; replace ink auxiliaries, reduce static electricity, and adjust darkness as much as possible.