The paper is devoted to the study of the optical indexes of UV inkjet imprints on polymeric materials. The appearance of new types of polymeric materials with different textures and colours, on the ...one hand, helps to expand the range of souvenir, advertising and gift products, and on the other hand, there is a need to provide accurate colour reproduction on different surfaces. An actual task is to ensure accurate reproduction of the corporate colour when branding business products, making advertising and souvenirs on various materials, which will contribute to the recognition of companies. The paper analyses the regulatory documents that guide the production and quality control of digital imprints. It has been found, that the assessment of colour reproduction accuracy requires a comprehensive approach and includes: selecting a reference for comparison; establishing the level of required reproduction accuracy (A, B and C); taking into account the viewing distance of imprints. Based on the results of the study, it was found, that the colour of the printed material has a critical impact on the chromaticity of colour. It was found, that the application of a white substrate in one layer allows for reducing the colour difference on the coloured samples, but is insufficient for accurate colour reproduction. The study found, that the misalignment of the ink layers is 0.12 mm, which is generally within specification tolerances, but the imprints show a white outline visible to the naked eye. A visual assessment of the corporate colour under study revealed contamination with another ink, mainly magenta; the paper presents possible causes of the detected contamination. Based on the research results, it can be concluded, that determining the influence of the properties of printed materials on the optical indexes of imprints will allow manufacturers to adjust their technological processes in order to obtain products of the predicted quality.
The structural properties and whiteness of the substrate surface markedly effect printing quality and are closely related to the primer coating processes. Herein, four different roller coating ...schemes were applied on MDF surfaces to change their structural properties and color, and the whiteness, gloss, and roughness properties of the substrate surfaces were characterized for UV inkjet printing. Data analysis was conducted to explore the effects of these variables on the color reproduction, relative contrast, and printing gloss of the MDF substrates. The results showed that, according to CMYK, L*a*b* values and spectral reflectance data, the finishing of the MDF substrate with a 40 g/m2 layer of transparent primer combined with three layers of white primer at 20 g/m2 per roll coating layer had the best color reproduction effect for UV inkjet printing. Regarding the effects of relative contrast, the correlation with whiteness and glossiness was significant, while the correlation with glossiness was minor. The inkjet printing gloss value was positively correlated with substrate primer surface whiteness, while it was negatively correlated with roughness. When the surface whiteness of the substrate was relatively high, the roughness was lower and the printing effects were glossier. We sought to optimize the printing effects of all aspects of the MDF substrate by primer coating. The results of this work provide a feasible application method to improve printing quality and enhance the added value of low-quality boards, as well as to further expand the application of UV inkjet printing in the wood decoration market.
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