Applied Mechanics and Materials Vol. 469

Abstract: Counterfeit and shoddy food is becoming more and more rampant, which has put forward higher request towards the food packaging anti-counterfeiting materials and technology. UV fluorescent inkjet ink not only can greatly improve the situation, also can enhance the artistic effect of packaging. What’s more, it is more difficult to counterfeit. In order to obtain color reproduction regular pattern of UV fluorescent inkjet inks, grey scale which contented 21 levels was respectively printed. The color reproduction abilities of three kinds of fluorescent inkjet inks were compared. The effects of lightness and glossiness of the paper on the color reproduction of fluorescent inkjet inks were discussed. The white balance was adjusted by changing the dot percentages of fluorescent inkjet inks. The experimental results showed that color reproduction regular patterns and abilities of red, green and blue UV fluorescent inkjet inks were different. The lightness and glossiness of paper had a great influence on color reproduction; the white with maximum lightness had been obtained.

Abstract: In digital printing process, the color reproduction quality is no longer determined by printing sequence, trapping, solid density and etc., since the technique is different from traditional printing technology. In order to analyze the effects of paper on color reproduction quality in digital ink-jet printing, three kinds of commercial paper were selected and a set of experiments were carried out by using color management technique to simulate the digital proofing. The density and chromaticity of both primary color and composite color in each printed were measured. The effects of paper’s characters on shadow, mid-tone and highlight were analyzed and discussed. Finally the influence on color reproduction quality principle, including chromaticity and absorbing characteristics of paper, was revealed. The conclusion has certain significance in directive function in ink-jet printing.

Abstract: Digital printing can print directly the information which will be printed on the package box by digital print machine and internet or computer, which removes the procession of color separation, makeup, plate-making in the traditional printing. The digital print can print any number package box at any time and at any place, which can realize the variable data printing, and which has a price advantage in the short version printing. Therefore, digital printing is a good method for personalized packaging printing.In digital printing, color control is important for print quality detection. In this paper the dot area percentage of cyan, magenta, yellow ink can be predicted by measuring the color’s spectral reflectance in order to control the ink’s amount in digital print and realize the color’s precise control of cyan, magenta, yellow. In the prediction model of three color ink’s dot percentage, the characteristic of spectral reflectance curves for the various color ink is analyzed, and each ink’s high reflectivity and low reflectivity which is high correlation with the dot percentage is chosen and is calculated by normalization method in order to get each ink’s dot area percentage’ prediction model. At last by measuring the paper’s spectral reflectance and the using normalization method, paper’s color can be described, and the effect of paper on monochrome color ink’s dot area percentage can be analyzed. The research has important significance for packing box’s digital printing’s color high-fidelity reproduction.

Abstract: This paper proposes a method of drawing natural and full of vitality printed original, adopting Sketchpad online painting software to simulate artificial hand-painted, and combines traditional plate-making technique to reappear the decoraton pictures of food packaging.The optimized process parameters are obtained through experiments, in order to provide technicalreference for designing and making new decoration printing products of food packaging based on the digital hand-painted plate-making in quantity. The results show that the optimized process parameters when printing pressure is 2.5kgf/cm²,the angel of scraper is 70° , screen distance is 9mm, mesh count is 200mesh/cm, are more suitable to present decoration effect required by food packaging, and the color error of printing products on the substrate of paper material is minimum. Contrasting the picture decoration effect presented by printing products shows that, the art hand-painted expression of food color, shape and taste based on sketchpad software possesses the advantage in enriching aesthetics of food packaging design and restoring reality of the sale food, The purpose is to help consumers know the food clearly, furthermore improve quality and market competitiveness of food packaging.

Abstract: The era of environmental protection and personalization has become increasingly prominent, and people not only focus on the beauty of the design, but also pay more attention to the quality of the clothing. For inkjet printing, the viscosity and surface tension of ink are major factors that affect the quality of ink-jet printing. In order to obtain a better print quality, the samples of five different viscosity and surface tension of ink were prepared respectively by changing the content of the resin and the surface active agent. Using these samples to print on the fabric by Epson printer, and to discuss the influence of the ink in different viscosity and surface tension on the ink-jet printing quality, such as apparent color depth (K / S), color parameters (L, C), permeability, clarity. The results showed that: with the increase of the ink viscosity, the apparent depth of color yield increased gradually and became darker in color. L value decreased gradually and had a increasing trend, and tends to be stable. C value increased and vividness of the color was improved. And it also had a certain impact on the infiltration resistance and clarity. Surface tension also had a significant impact on the depth of the apparent color, vividness of the color and directly affected the ink permeability and clarity.

Abstract: Nowadays, inkjet prints have been universally used in packaging, posters and window show promotional items. The quality of the inkjet prints attracts more attentions, especially for posters and window promotional item generally require bright colors, saturation, and a long print life. Generally, the color of inkjet prints fade gradually when being placed outside and radiated directly by sunlight or under lamp, meanwhile, the density decreases and color difference increases. All these phenomena happened make inkjet print cannot meet the requirements of customers to color within the time of use. Light fastness of inkjet prints under high intensity level of illumination is studied in this research. Ten different brands of papers were exploited to print a special design test target by EPSON inkjet printer and the printing test samples were irradiated under high level of illumination so that the aging process can be accelerated. After being irradiated for different time intervals, then color differences were measured by using spectrophotometer. The results show: the color differences of prints printed by using the brands Kodak and Xiongguan papers changed greatly after prolonged exposure to light. These conclusions are very useful for the correct choosing of inkjet materials under suitable inkjet printing condition.

Abstract: From printing technology’s perspective, printing quality is determined by the comprehensive effects of all the printing product appearance features. The factors which dominate to comprehensive effects of all the printing product appearance features include definition of image, tone rendering, color rendering, uneven, and gloss, etc. In the print quality evaluation, this factor is affected by many other factors. Therefore, printing quality evaluations are indeterminate. Most of printing quality evaluations belongs to fuzzy theory, which brings a lot of troubles to the printing quality evaluation. The paper mainly research that the synthesis decision-making method in fuzzy mathematics theory is used to tone reproduction of printing quality, and analyze the feasibility of applying Fuzzy Synthetic Evaluation Model in printing quality evaluation. The synthesis decision-making method is used to determine the tone indicator system of printing, establish Fuzzy Evaluation Mode, and analyze the influencing factors. Through the evaluation of numerous experts, the weight will be offered for the specified factors. On the basis of weights, printing quality can be evaluated by determining the membership function of all the factors and calculating the score through fuzzy algorithm. The paper studies have shown that the synthesis decision-making method in fuzzy mathematics theory can be used to solve the printer quality evaluation problem and is valid for evaluating the results in actual application.

Abstract: In the process of printing machines increasing and reduction of speed, the image collected from online detection system for different speed of printing needs picture adaptive processing. In this paper, there are two methods put forward to realize above goal. One method is sequential similarity detection algorithms and the other is ratio value. Apply with VC++ programming to realize image matching on the premise of the unique CCD detection equipment. The experiment results show that: sequential similarity algorithm on the premise of printing machine running in low speed, by comparing with threshold to realize variable-speed imaging. The ratio value method can be used for a variety of printing speed and it has high speed, high detection efficiency and wide range of application.

Abstract: IIndoor photo has been widely used in products of shopping malls publicity, light box advertising, wedding photography, posters, engineering and landscape effect picture, digital photo album, art photo, antiquing canvas and window advertising. PP synthetic paper which was the most common indoor photo materials was selected as the research object, and it was printed by the photo printing machine. A series of experiments were carried out according to its printability. The main parameters of PP synthetic paper such as solid density, dot gain and relative contrast were tested, which provided a theoretical and practical basis for digitization of indoor photo.

Abstract: Nowadays, many domestic printing enterprises still rely on artificial visual means to weed out waste, labor-intensive, time-consuming, subjective factors serious influence, the test results not being uniform, especially with the improvement of printing speed, gradually unable to meet the needs of the production. In order to solve the problems in the conventional assay and promote the development of China's printing industry productivity, there is an urgent need to develop the quality of printing online full screen detection system, with the rapid development of modern printing technology, the objective is to test and evaluate. In this paper, machine vision inspection technology, digital image processing technology is used in order to achieve the online testing and feedback of print quality. Dynamic partitioning method is based on standard proofs and proofs of defective segmentation and matching. According to the type of image resolution and the desired accuracy of detecting the type of design image segmentation method, thereby performing the detection and analysis of the color information. Secondary identification defect classification technology is used to change the defect classification, and then display the corresponding defect types. Compared with the traditional printing quality, the high detection print quality inspection speed and precision requirements have been reached, thereby the overall quality of the printed product is improved.