Papers by Author: Wan Zhang

Abstract: Fluorescent ink can be applied not only in anti-fake packaging products, can also be used on other field to present a special artistic effect. The samples of fluorescent inkjet ink were prepared by changing the type of solvent, the excitation and emission wavelengthexcitation and emission intension were measured,and fluorescent quantum yield were calculated. The result shows Solvent has large effect on the luminescent intensity and fluorescent quantum yield of fluorescent material, and the optimal formula of solvent is Ethyl Acetate: Propylene Glycol Monomethyl Ether: Acetone=0.00:0.50:0.49.

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: The formation of color images are generally divided into two methods: additive color imaging based on color light mixture and subtractive color imaging based on colorant mixture. Additive color imaging refers to the color image mixed by a certain percentage of the three primary color lights: red (R), green (G) and blue (B), such as LED display, cell phone screens, digital cameras and others. Subtractive color imaging refers to the color image generated by light mixture reflected by each colorant, due to some light of different wavelength in the white light separately absorbed by certain colorant after mixing a certain percentage of the three primary colorant: cyan (C), magenta (M) and yellow (Y). Inkjet, color laser printing, inkjet printing, etc. belong to the subtractive color imaging. Most commonly, printing also belongs to the subtractive color imaging. This thesis is based on the characteristics that fluorescent materials can produce colors under UV excitation, designing and preparing three fluorescent inkjet inks which can respectively produce red (R), green (G), blue (B) under UV light excitation, using inkjet printers to print color images, investigating the imaging mechanism of the additive color based on fluorescence inkjet printing, and observing the imaging results. The results show that color effect of monochrome image is good, and the color deviation is large after overlapping different colors.

Abstract: Recently flexography develops faster and faster. The fine degree and the speed for making plate is asked to be higher. Flexographic cyrel digital imager (CDI) can meet the requirements. This article analyzes briefly to the parameters of making plate of CDI. The parameters for affecting the flexographic printing can be ensured. And the correct exposure time is made for making plate. Results show that the quality control is a systematic process. When printing different production, different screen lines, exposure parameters are adopted. By controlling the exposure time, the dot gain can be controlled effectively.

Abstract: The infrared absorbing inkjet ink is composed of infrared absorbing materials, resin, assistant agent and solvent that has a great influence on the main performance of the ink. Based on the consideration of environmental factors, five alcoholic solvents were chosen and prepared into ink samples respectively. The effect of different solvents on the properties of the ink was discussed. Then the ink sample was prepared by the most optimal proportion of blends with solvent through the principle of formulating of recipe, the printing sample was attained and tested. The experiments showed that the solvents had a great influence on the properties of the viscosity, infrared absorption strength, surface tension of infrared absorbing ink, which directly affected the ink-jet printing eligibility and security effect. The developed ink has good performance and security effect.

Abstract: Fluorescent intensity is an important indicator to evaluate the performances of fluorescent inkjet ink. It can be affected by many factors, such as the structure and content of fluorescent material, the polarity of solvent, the type and content of resin, optical properties of different substrates. Formulation of red fluorescent ink-jet ink was designed in the paper and ink samples were prepared to explore the impact of fluorescent material content, solvent polarity, and resin type on fluorescent intensity. Results show that: fluorescent intensity gradually increases as fluorescent material content increases, when the content reaches 1.0%, fluorescent intensity decreases; saturated solubility of fluorescent material at room temperature (25°C) is 1.6%; When propylene glycol monomethyl ether acetate (PMA): ethyl acetate: n-butyl acetate = 0.36:0.42:0.22, resin EP-609 content is 16%, fluorescent intensity reaches to the highest.

Abstract: With the aim to study the effect of prepolymer on performance of UV ink-jet yellow ink , prepare UV ink-jet yellow ink color paste by change prepolymer and pigment/binder , test it’s particle size and distribution, explore the effect of different prepolymers and pigment/binder on the dispersion property; make ink color good dispersion paste into ink by using different film forming prepolymers, test the surface tension , viscosity , and curing speed, explore the effect of different prepolymers on the performance of UV ink-jet ink. The results indicate that, prepolymer on the dispersion property has great influence, color paste prepared by prepolymer CN2303 at pigment/binder for 2:1 has minimum particle size, and has good dispersion, film forming prepolymers has great influence on viscosity and curing speed of ink, has little effect on the surface tension of ink.

Abstract: The emulsification ratio of ink has an important effect on ink-transfer performance and printing quality. The UV offset ink of gold and silver cardboard was prepared by three-roll grinder. Ink was emulsified by adding different amounts of water and the ink samples with different emulsification ratio were made. Printability tester was used to proof, test the ink transfer performance, set up Ink transfer equation, confirm the parameters of f’，b and k, and investigate the influence of emulsification ratio on ink-transfer performance. Test the solid density, dot gain and relative contrast value of proofs, analyze the effect of emulsification ratio on printing quality. The research results show that when the ink of plate was large, the amount of ink transfer and the volume of ink on the plate are basic in a linear relationship. When the emulsification ratio of ink is 11.76%, the value b, the solid density and relative contrast value are the biggest. When the emulsification ratio of ink is 6.25%, the value f’ is the biggest. The dot gain is the smallest while the emulsification ratio is 15.67%.

Abstract: UV screen printing Photochromic ink mainly includes pre-polymer, monomer, Photochromic materials, Photoinitiator, etc, and the curing process of ink is that under the irradiation of UV light source, the liquid substances with chemical reactivity are rapidly changed to the solid state, in this reaction process, Photoinitiator can promote the advancement of reaction, therefore, Photoinitiator directly affect the curing performance of inks. The inks are respectively prepared by changing the quantity and type of Photoinitiator, and the curing speeds are tested. The result shows when the quantity of Photoinitiator is 10%, the curing performance of ink is the best. In addition, the formulation experiment is made by selecting three Photoinitiators with best curing performance. The result indicates that compared to other formulations, the ink can obtain the biggest curing speed only by Photoinitiator 907, and the optimal curing speed is 68m/min under curing power 100w/cm.