Color Box Printing Technology
Now, the color box printing quality testing technology mainly has density approach and chromaticity approach two. In the meantime, density method is a process control method, according to the thickness of the ink layer to control the key links of the printing production process. Chromaticity method is a high-precision system control, according to the chromaticity or spectral measurement of the intuitive color control, but need to take into account the printing material, the use of the environment and the purpose of the test. In the completion of the approach, both the offline approach can be selected for manual sampling, can also be selected for active detection of the online approach. 1, special materials printing quality testing and control In the color box packaging, special materials and the use of new materials and push the trend, such as cigarette packets from paper soft packets, cardboard hard pack development to aluminum foil gold and silver cardboard hard pack. These high-gloss surface of the composite or coated materials with a metallic luster and refractive surface, printed on a variety of colors after the exquisite picture, giving people the feeling of high-grade elegant, can greatly enhance the value-added products space, in the high-grade color box in the use of a very wide range. This kind of high gloss surface material has intense metallic luster due to the flat surface coating, when the incident light shines, there will be strong specular reflection. As a result, the object surface color surface will be followed by changes in the angle of investigation and change, resulting in the printing process of the color is not easy to control, so that the printing plant to face to ensure that the same batch of prints, and even different batches of prints of the ink color common quality control problems and its special testing technology requirements. Selection of special materials printed color box printing in addition to four-color printing color, there are many spot-color and anti-counterfeiting process, and its detection content includes density, dot expansion, registration and gloss. Due to the limitation of special material surface gloss, in the density and dot measurement, it is necessary to use d/0 to measure the optical geometric conditions of the test instrument, it is best to use according to the principle of spectroscopy, the visible light 400 ~ 700nm wavelength band will be divided into 31 measuring distance, measuring the object color spectral reflectivity, and then derive the color CIELab value and the color difference of the spectroscopic spectrometer, such as X-Rite’s SP series. Spectroscopic spectrometers such as X-Rite’s SP series. This ensures the accuracy and reliability of measurement data for high-gloss surface materials. Applied to general materials 0/45 geometric conditions of the measuring instrument, such as X-Rite900 series is unable to obtain a common and accurate role. 2, spot-color printing quality detection and control In the color box packaging products printing, due to spot-color printing has a large area of the field color block, eye-catching color, shelf show effect; reduce the color difference due to the overprinting of dots, dot deformation occurs, the color is stable, easy to identify, and thus a lot of use of spot-color printing is the basic characteristics. Now, the domestic color box printing enterprises on spot-color measurement and control means is relatively backward, most of them are still in the stage of relying on the experience of workers to allocate spot-color ink, there is a spot-color ink ratio is not accurate, distribution time is long, the subjective factors affect the shortcomings of the big. Therefore, the choice of color matching system is the best solution to the problem, but also the world color box quality control and detection of mainstream technology and development direction. Spot Color Matching System is a system composed of computer, color matching software, spectrophotometer, analytical balance, ink leveler, ink spreader and printing suitability meter. Spot color ink matching system can be tested and experimented by the color box printing enterprise’s printing material, ink and its color matching data parameters stored in the system database, the color matching software can be based on the spot color samples provided by the customer for spectrophotometric measurements, the use of computers to actively carry out the color matching analysis and color matching operations, according to the customer samples and color samples with the CIELab value, the density of the value of the △ E to control the conditions of the color matching to provide printing control parameters, and then can complete the spot color ink matching system, and then can be completed. Brush control parameters, and then can complete the data of spot color ink matching. For example, including hardware spectrophotometer SpectroEye and InkFormulation of Switzerland GretagMacbeth ink formulation system, its SpectroEye can not only measure the print dot, density value, but also can measure the hue (Hue), saturation (Saturation) and brightness (Luminosity); InkFormulation requires only a few concentration scales to build an accurate database.
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