Applied Mechanics and Materials Vol. 469

Abstract: The material for ink-jet printing is very extensive, but now paper media is the most commonly used one, because the image of glossy ink jet paper printed clear and bright, shiny, light fastness and excellent color fastness in the aspects of indoor display packaging. Therefore, this paper combined the traditional test method and modern computer image analysis technology together, to formation the evaluation system of color rendering performance on a suitable color ink jet paper, in order to qualitative and quantitative evaluate to paper printing color rendering.This paper mainly used six kinds of different brands glossy inkjet paper as the pattern and carries on the experiment measurement and objective visual subjective evaluation. Subjective evaluation aspect, choose a certain number standard observer to do subjective quality evaluation. Objective evaluation aspect, using the experiment testing paper properties, through test the paper print image macro and micro color reference which on the different brand color ink-jet printing paper, and add the analyze the effects of combined with the basic properties of different paper color rendering of ink-jet paper, to ensure comprehensive and objective reflect the effect of color rendering.Through the above methods, qualitatively and quantitatively evaluate of the different paper pattern of the color rendering performance, it would be provide reference and evaluation method for glossy inkjet paper in the research of color rendering effect.

Abstract: Hiding information in a color image is an effective method for the purpose of anti-counterfeiting, it can accurately identify authenticity in a certain range, and it is not easy to be copied and replicated. A new kind of watermarking algorithm for halftone images is proposed. Firstly the color image is treated as R, G, B single channel images, by using error diffusion algorithm the single channel image is converted into a halftone image, and then the watermark information is embedded in the halftone image by the proposed scheme of pixel swapping. Experimental results show that large amount of information can be embedded and extraction of the watermark information is clear, under conditions of rotating, clipping, etc, the watermark information still can be effectively extracted. This scheme can be used in packaging anti-counterfeiting printing.

Abstract: From the prospect of the printing forgery prevention technology, this paper systematically analyzed the principles of digital watermark in printing forgery prevention technology, based on this, it proposed wavelet transforming printing forgery prevention algorithm based on chaotic characteristics, in this paper, by using digital watermark image scrambling technology based on chaotic mapping to encrypt the wavelet transforming coefficient, then choose the different K value in chaotic mapping and the size of the scrambling image to combine the the cryptography technology and the wavelet transforming technology for resisting the various printing forgery attack effectively. In the end, the author made a detailed design about the wavelet transform printing forgery prevention system which based on chaotic characteristics and put it into fact by VC++, then validated the algorithm by experimental result, then compared it to the traditional watermark algorithm from the aspect of the image compression and anti attack ability to prove the stability and robustness of the algorithm this paper proposed.

Abstract: Abstract. Gravure printing has the characteristics including thick ink layer, bright and homochromatic color, rich and sharp tone, and strong stereoscopic impression. In the packaging-printing field, gravure printing gets more and more attentions. But in the region of gravure printing process, the study on gravure printing ink transfer is not as deep as offset print. Most researches just stay in the level of qualitative analysis, but the quantitative analysis researches are still insufficient. The factors which impact gravure printing ink transfer are not only the volume of engraving ink cell, but also printing process. In this paper, gravure printing ink transfer is analyzed quantitatively from the point of views of gravure printing pressure, printing speed, scraping blade pressure and ink viscosity. The following research has been done in this paper. Firstly, electronic engraving machine is used to engrave eight different area ink cells by 45° ink cell angle and 70lpc screen line number on the same gravure roller. Secondly, gravure proofing machine is used to make proofs in different process conditions. Thirdly, density meter is used to determine density of cell ink, and balance is used to determine the weight of ink which moves from the plate onto the paper. Finally, to analyze the influence of different printing processes on gravure printing ink transfer. The research results show that gravure printing ink transfer is influenced certainly by different printing processes. Printing process has a certain influence on the gravure printing ink transfer, and the influence degree of different dot area rate of cell is different. The doctor blade pressure and ink viscosity influence greatly gravure printing ink transfer.

Abstract: For most plastic packaging products, injection molding is the most convenient, simple, widely applicable, especially for those thin, complex structure, smooth surface, and small moulds. Overdependence on experience, it is difficult to quickly design excellent products with short production cycle. In this paper, a common thin CD packaging mould was taken as a research object. By orthogonal experiment method and MPI software obtain the amount of warping deformation and a better group of process parameters. Within the range of orthogonal test, we explore the influence of various process parameters on warpage of injection. Besides, according to variance analysis that it is different from visual analysis to explore the main factors significantly, so that we obtain the most reliable and the best group of process parameters.

Abstract: Traditional maps have the characteristics of high and low terrain, using the method of contour. Although contour map can express relief form, the stereo sense is not intuitive. In this paper, according to the characteristics of UV inkjet printer, the designed test pattern was printed, ink layer thickness of different colors was measured to establish a quantitative relationship between ink thickness and ink layers. The contour map of Taiwan was chosen, in graphics processing software, to extract the contour vector image according to its elevation. According to the relationship between ink thickness and ink layers, the corresponding relation table between the actual elevation and ink layers was established. Layered corresponding table was designed, according to the contour of layered principle. The experimental result shows that the color topographic map with stereoscopic effect can be obtained, through UV ink-jet printer.

Abstract: First, the study chooses ten kinds of offset paper. By using a dynamic penetration analyzer (HVL-PDA) and water as test fluid, the dynamic absorption characteristics of the ten kinds of offset paper are measured. At the same time, proofs of offset printing patterns of these ten kinds of offset paper are made by using a printability tester. Then the depths of ink penetration in ten kinds of offset paper are measured by the Three-dimensional video microscopy system and the study analyzes the effect of paper dynamic absorption property on penetration depth of ink. The results of the analyses show that the penetration depth of ink is closely related to dynamic liquid absorption, thus the permeability of ink in offset paper can be predicted from the dynamic liquid absorption of offset paper.

Abstract: In order to research the relationship between ink permeability and dot gain of different paper, four kinds of coated paper and two kinds of printing paper were chosen. Ink marks method was used to measure ink permeability of four kinds of coated paper and two kinds of common printing paper. After the ink marks were printed on each of the six kinds of paper, the length of them were measured, then the reciprocal of the ink marks length was multiplied by 1000 to obtain the value of the ink permeability. Inkjet printer was also used to print yellow GATF step-wedge simulating offset printing on the six kinds of paper, then using an optical densitometer to measure the dot gain. Conclusion shows that non-coated paper is higher in permeability than coated paper, which results in high percentage of dot gain.

Abstract: The Internet of Things technology used in agricultural products, such as food safety traceability management is taking the technological advantages of the Internet of Things RFID (Radio Frequency IDentification) is non-contact automatic fast read and write data encryption, in order to achieve a unified management and efficient flow of work in coordination.This thesis reports a production method of conductive nanosilver jet ink. The ink can be used to directly print RFID antenna coil. In the method using silver nitrate as silver source, hydrazine hydrate as a reducing agent, polyvinyl pyrrolidone as a protective agent. Obtain the dispersion of silver nanoparticles through chemical reduction reaction. The dispersion was purified and used inkjet printer into a graphic on glossy photo paper, after 180 °C sintered for 15 minutes with good conductivity, RFID antennas to meet requirements.

Abstract: Moire, an abnormal printing pattern formed by irregular screen tone, may adversely affect the printing quality and should be avoided during printing. Hence, it is necessary to understand the factors contributing to its formation. Being one of the most important factors, the effect of screen angle is discussed in this paper. To obtain the most suitable screen angle and confirm its rationality, Photoshop is used to simulate Moire patterns under different screen angle conditions and analyze the relationship between screen angles and formation of Moire pattern. When mixing two of Cyan, Magenta, Yellow, and Black colors randomly while keeping the others constant, the size of the Moire is not affected by screen angles but by the angle differences. When the difference is at 28° and 38°, Moire pattern is not obvious and the dots are evenly distributed. The screen angle difference and the screen angle of the key color are also analyzed from the Moire pattern obtained by varying screen angle between C, M, and K (Black) in the simulation study. The results show that it is reasonable to set screen angle for strong color at 15°, 45° and 75°.