Ink gloss is a key indicator to measure the gloss of ink film, which affects the visual effect of printed matter. In practical applications, surface printing inks usually need a certain gloss to attract consumers; Because the lining ink is located in the inner layer of the package, it generally does not have high requirements for gloss.
When printing, too much solvent is added, which will change the composition and physical properties of the ink, reduce the leveling of the ink film, and reduce the gloss. The solvent contains water or the humidity in the workshop is high, which will interfere with the effect of ink components, make the surface of the ink film rough, not only reduce the gloss, but also may cause the ink to whiten.
Gravure ink gloss detection method
Detection principle
The gloss of the specimen ink is determined by measuring the ratio of the specimen to the reflected light metric of the standard surface (the reflectance metric of the standard surface is set to 100%) under the illumination of a specific light source. Different models of gloss meters have different light sources, accuracy, and data processing, but the principle is the same. The DFH-80 model, for example, uses advanced optical sensors and circuitry to measure and display results quickly and accurately.
Detection steps
Printing sample preparation: The tested ink is placed on the low-density polyethylene film with a smooth glass rod, and then scraped into a uniform thin layer with a width of 60mm and a length of 100mm from top to bottom with a wire rod at a uniform speed and stability. After scraping, it is placed for 2 hours, during which the ambient temperature and humidity are kept stable, so that the ink is fully dry and stable.
Gloss measurement: Place the adjusted gloss meter probe on the black paper lined with the printing sample, and level the film with the help of the light meter to reduce background light interference. In the case of the KCZ-1 Specular Gloss Meter (60° angle), the probe should be in close contact with the printing sample perpendicular to the sample in a standard environment, avoiding tilts or gaps, ensuring that the light reflection is normal, and reading the measurement data.
Processing of test results
Since the gloss of the surface of the printing sample may be uneven, it is necessary to measure the upper, middle and lower points of the printing sample, and take the average value as the final gloss value of the ink. If the top, middle, and bottom measurements of a sample are 85, 88, and 86, respectively, the gloss value is (85 + 88 + 86)÷ 3 = 86.3. In fact, the number of measurement points can be increased as needed, the accuracy can be improved, and data files can be established to record and analyze the gloss data of different batches of inks to support quality control.
In conclusion, gravure ink gloss inspection is essential to control the quality of printed materials. From the demand of gloss in different printing scenarios, to the influence of solvents, environmental humidity and other factors, to the scientific and standardized operation of the detection steps through the photoelectric gloss meter, and the rigorous processing of the test results, this series of links are closely linked. Accurate detection of ink gloss helps printing enterprises to adjust production parameters in a timely manner, ensure that products meet market demand, improve product competitiveness, and also lay the foundation for quality improvement and technological progress in the entire printing industry.
