Bao Ling Tang

Effect of Paper Surface Characteristics on Dot Gain in Ink-Jet Printing

Four kinds of ink-jet papers with different surface characteristics are chosen in this paper, by the ink-jet proofing experiments, the influence of surface characteristics to dot gain is studied, and the law of dot gain with paper surface characteristics is discussed. During the experiment, surface properties including absorbency, gloss, roughness and whiteness are tested firstly; then, the standard wedge of GATF is printed on these papers in the same printing conditions; finally, the dot gain is tested by SpectroEye. After experimental data processing and analysis, dot gain curves of different ink-jet papers are concluded, the law of dot gain with ink-jet paper surface characteristics is summarized. The results show that dot gain is different in different paper, the evaluation of 3# is the best; dot gain is also different with different colors in the same paper, and it is serious in cyan but light in yellow; the biggest dot gain appears in different contrast with different colors, cyan appears near the 65% dot area. The result of this paper offers a certain theoretical reference and practical guidance to the selection, the research and development of ink-jet paper as well as the improvement of ink-jet qualities.

Research into Digital Watermark Algorithm Based on Wavelet Domain

In this paper, the key research was focused on the algorithm based on wavelet domain after analyzing and comparing several watermark algorithms. Disperse Wave Transform(DWT) watermark and Disperse Cosine Transform(DCT) watermark are both belong to transform domain technology, and they have more robustness than spatial-temporal domain technology, and DWT is superior to DCT. DWT can use the spatial-frequency characteristics of Human Visual System, and Mosaic will not appear in reconstruct image. DWT also can use image fusion technology to disperse watermark into multiple scales of carrier data, and got more robustness. In this paper, watermark embedding based on wavelet domain in which raster data are carrier was performed, then extracting and detecting watermark were done. Experiment results show that digital watermark based on wavelet domain will get better invisibility and robustness, and can be used in following the data by digital fingerprint.

Study on Improvement of Photopolymerization Curing Performance of UV Ink

UV ink has many advantages such as less pollution, high curing speed, saving energy, so it has been widely applied in traditional printing and emerging digital printing. In this paper, the two curing principles in UV ink which are free-radical curing and cationic curing, are discussed and compared, and the factors that affect the curing rate are analyzed through the comparing experiment of the curing rate. In the last, the selection principle of photoinitiator is established by means of analyzing and comparing curing rate when various photoinitiator or photoinitiator combinations is used in UV-cured ink. These studies have certain significance for improving the curing efficiency of UV ink and its application.

Polyurethane-Acrylate Composite Emulsion Applying to the Pre-Coated Adhesive Film

This paper studied on the application mechanics and characteristics of the polyurethane-acrylate composite emulsion applying to the pre-coated adhesive film of paper and plastic laminating. The formula design and synthesis method of the polyurethane-acrylate composite emulsion was researched, and the physical properties of the copolymer emulsion was tested by infrared spectroscopy (IR), particle size analysis, gel permeation chromatography (GPC). According to mix the waterborne polyurethane acrylate emulsion to the waterborne rosin emulsion, the hot melt pre-coated adhesive was obtained. The experimental results based on the physical properties and image analysis of the pre-coated adhesive film of paper and plastic laminating showed that: the adhesive film coated by this hot melt adhesive had a high gloss and adhesive force, it improved the application performance of the pre-coated adhesive film of paper and plastic laminating in the printing and packaging industry.

A Monitor Calibration Model Based on Artificial Neural Network

There is a very complicated nonlinear relationship between the input digital image pixel value and the display colors, which is difficult to be described by traditional linear methods to achieve high accuracy. In the study, a monitor calibration model is established based on artificial BP neural network theory and by the hue angle range of the experimental data display classification. Because of the good simulation of nonlinear properties of the BP neural network, the calibration model achieves high accuracy. The color error mean value between the chroma value to be displayed and the chroma value driven by the image pixel value which is calculated by the calibration model is rather less than that of the minimum range of the human eye can identify. The calibration model could be used in the gamut matching phrase in the printing color management system, when the monitor is severed as an output device.

Study on the Printability of Coated Paper on High-Fidelity Digital Printing

The impact of coated paper printability for image quality on the high-fidelity digital printing was studied in this paper. Compared with the traditional printing technology, high-fidelity digital printing technology is more likely to expand the color gamut, maintain the original tone linear and produce vivid image. The performance of coated paper to a large extent determines the image quality. In order to get high-quality printed matters, the mechanism of the coated paper printability influencing on the performance on high-fidelity digital printing is need to be researched in-depth. The printability of coated paper was studied from several aspects in this paper, including the structural properties, roughness, optical properties, absorption etc, the relationships between these properties and printing color, dot reproduction performance were also studied. Based on the previous theoretical and practical studies, the printability evaluation system of coated paper on high-fidelity digital printing was established initially. On digital printing, accurate color management technology also affects the printing quality as the performance of coated paper, so the advanced color management technology was also used in the current study. The results showed that the pore structure and the absorbent of coated paper were the most important factors for affecting the printing quality, and the roughness and optical properties of coated paper also had a certain impact.

Study on Polyurethane-Acrylic Hybrid Emulsion Applying to Water-Based Ink

Polyurethane-acrylic composite emulsion was synthesized by swelling polymerization with aqueous polyurethane dispersion as seed, and acrylic as monomers. The obtained polyurethane-acrylic (PUA) composite emulsion were characterized by means of IR spectra, and the results showed that the obtained emulsion was hybrid emulsion of polyurethane and acrylic, which had smaller particle size and higher viscosity and was more suitable for the preparation of ink. The obtained water-based PUA emulsion and alkyd resins were used as ink binder. The obtained water-based ink had good water resistance, color density, gloss and friction fastness.

Study on Anti-Bacterial UV Ink with Zinc-Copper

Packaging security and functionality has been the research focus. In recent years, people pay more attention to the functionality of ink used in packaging. In this paper, a kind of zinc-copper antibacterial agent was made by attached the metal Zn2+, Cu2+ on the zeolite by ion exchange and the zeolite modified was used as a carrier; Than the zinc-copper anti-bacterial UV ink was prepared by mixing and grinding zinc-copper antibacterial agent, polyester acrylate, HDDA, TMPTA, titanium dioxide and other element of UV ink; The UV ink prepared was printed on paper. When the UV ink printed was dried, the property of anti-Escherichia.coli(anti-E.coli) and anti-staphylococcus aureus of UV ink prepared was tested by the anti-bacterial experiment. This study has good application prospect in the area of safety packaging.

Effect of Instrument Precision on Area Quality Measurement Used in Digital Printing Quality Assessment

In this study the effect on quality measurement introduced by input precision of instrument in image digitizing process was verified through a series experiment. Two categories of samples, which were outputted by EPSON Stylus Pro7880c digital inkjet printer and Xerox DocuColor5000 digital xerographic printer individually, were transformed into digital image with a normal flatbed scanner in 600 DPI, 1200 DPI and 1600DPI resolution. The area quality attributes such as graininess, mottle, NPS and banding were surveyed and analyzed with the aid of PIAS™-II personal image analysis software to investigate the stability of normal instrument used in digital prints measurement system. Results show that precision demands are different for various quality parameters and different application backgrounds, namely it is precise enough for common industry detection which has lager tolerance, but higher resolution does good to more effective and more precise measurement especially in R&D.

Study on Preparation and Property of Acrylic Resins Used for Water-Based Ink

In this paper, a kind of water-soluble acrylic emulsion with methyl methacrylate (MMA) and butyl acrylate (BA) as hard and soft monomer respectively, acrylic acid (AA) and hydroxypropyl methacrylate as functional monomers, ammonium persulfate (APS) and ammonia as initiator and neutralizer respectively, was prepared by emulsion polymerization. The resulting emulsion possesses high solid content, low viscosity, high stability and film-forming properties, indicating that it would be applicable to water-based ink. The effect of the ratio of MMA to BA on the film-forming properties of resin and the influence of AA and HPA on the water-soluble property and viscosity of resin were investigated, and the relationship of reaction temperature and the emulsion stability was also studied. This paper can provides a certain reference to synthesis of acrylic resin and application of acrylic resin to the water-based ink.