Throughout the entire conference, we will be reviewing advances in a variety of different technical areas. Each one of these areas are seeing massive amounts of rapid change and increasing complexity.This talk will delve into some of the major drivers for change / complexity from a printing industry vantage point and the opportunities that these new technologies create for printing product scientists and engineers. These new customer opportunities are limited by our ability to manage change / complexity, as much as the emergence of new technology. It will offer strategies for product developers to manage change / complexity and review some of the emerging technologies that will revolutionize printing in the near future.

Colored textiles are influenced by a wide range of parameters due to highly diverse textile structures and the resulting textures. In practice, variation in color appearance due to changes in surface characteristics is a serious management problem.The goal of this study is to understand the effect of texture on visual perception of color in inkjet printed woven textiles. Cotton woven samples were constructed with nine different weave structures. The surface characteristics of the samples were determined using the KES-F and profiling instruments. Each sample was digitally printed with identical squares of primary colors of cyan, magenta, and yellow and secondary colors of red, green, and blue. The amount of ink applied was controlled consistently with an image editing software. CIE L* values were calculated from the measured reflectance. For visual assessment, the rank order method was applied and 25 observers ranked the perceived texture and color lightness of each sample.By employing the rank order method, a perceived visual texture scale was obtained statistically from the specified rankings. The scale of visual texture shows high correlation with the friction coefficient (MIU) and the mean deviation of the MIU (MMD). The roughness (SMD) was not correlated with the scale of visual texture. The surface measurements from the profiling instrument (Pa) are also correlated with the scale of visual texture. The scale of the perceived color lightness was estimated from the assessed rankings. The measured CIE L* values and the scale of perceived lightness have a linear relationship for the primary and secondary colors. The scale of the perceived texture and the CIE L* values showed a relatively good correlation, but the surface characteristics of the weave structure, such as highly oriented yarn on the surface, can affect the light reflectance differently.

Efforts to adapt and extend graphic arts printing techniques for demanding device applications in electronics, biotechnology and microelectromechancial systems have grown rapidly in recent years. This paper describes the use of electrohydrodynamically induced fluid flows through fine microcapillary nozzles for jet printing of patterns and functional devices with sub-micron resolution. Key aspects of the physics of this approach, which has some features in common with related but comparatively low resolution techniques for graphic arts, are revealed through heuristic models and direct high speed imaging of the droplet formation processes. Printing of complex patterns of inks, ranging from insulating and conducting polymers, to solution suspensions of silicon nanoparticles and rods, to single walled carbon nanotubes, using integrated, computer controlled printer systems illustrates some of the capabilities. High resolution, printed metal interconnects, electrodes and probing pads for functional transistors and representative circuits with critical dimensions as small as 1 micron demonstrate potential applications in printed electronics.

Textiles Inkjet printing as a new dyeing method with higher resolution, lower pollution and shorter run length has attracted more and more people's attention. Pigment inks have become one of the main colorant materials in this technology for its excellent light fastness and suitable to all sorts of textiles. However most of organic pigments with low polarity are hard to be wetted and dispersed in aqueous media, therefore the organic pigments should be modified before their application. In this paper, waterborne nanoscale pigment dispersion including Copper Phthalocyanine blue (P.B.15:3), Quinacridone red pigment (P.R.122), and Monoazo yellow pigment (P.Y.14) have been prepared by phase separation method and direct milling with dispersants method respectively. The properties (stability, particle size and apparent viscosity) of dispersion which prepared by different method were compared. The results show that the pigment dispersion has higher stability to alcohols, temperature and storage, and also lower viscosity; the phase separation method was more suitable to preparation of pigment dispersion for formulations of inkjet inks than direct milling with dispersants method; TEM photo indicated that the pigment particles were uniformly distributed in aqueous media and the XRD curves indicated that the pigment crystal was not changed after encapsulation by phase separation method.

Dyes and pigments play a crucial role as the colorants in the imaging areas. In the period of black & white copies, organic pigments have extensively been studied as photoconductors for electrophotographic photoreceptors. However, nowadays, pigments have more and more attracted attention as colorants, not only for color copies based upon the electrophotographic process, but also for inkjet printers. The color of the dyestuff is mostly determined by its molecular structure; whereas that of pigments arises from the molecular structure as well as intermolecular interactions in the solid states. Therefore, the color of pigments can be influenced by molecular arrangement, i.e., crystal structure. In present keynote, I begin with a brief introduction about the difference between dyes and pigments in general and then talk about the intermolecular interactions in the solid state from the standpoint of the crystal structure. I will also introduce you a variety of polymorphs in pigments that are isolated as single crystals and discuss some representative factors which induce phase transition, leading to different colors.

In order to better understand the drop impaction and post- impaction dynamics of digital textile printing, various numbers of drop-on-demand inkjet drops were deposited on textiles, and the process was visualized using a high speed camera. As a comparison, experiments were also conducted on a high quality inkjet paper under the same conditions. Dynamics of DOD drops accumulation and spreading on the substrates and final state ink distribution show drastic differences between digital printing on textiles and paper. The effect of yarn hairiness on ink deposition was also demonstrated.

Biofabrication describes the inkjet application of bioink which may include active compounds such as drugs and living cells as well as non active, scaffolding materials to build two- and three-dimensional constructs for medical treatment. Many of the challenges in tissue engineering generally and biofabrication specifically are biological in nature; however, many appear to fall within the realm of imaging and science and technology. One challenge is to arrange the donor cells into the exact patterns that will promote growth towards the desired tissue form and function. Of the many approaches that have been suggested to accurately place cells the inkjet printing approach is one of the more interesting. In these devices researchers have tailored their bioinks by two approaches, namely using new biomaterials that fit the processing window of commercial printers or developing new systems that use the biomaterials as bioink directly. Tailoring the physical properties of these inks, and developing printheads optimized for these properties will improve cell density, and the tissue fabrication speed. Biofabricated tissues can be used to build models of the effects of local environment on different cell types. The models can be incorporated into computer design and simulation environment in order to predict tissue function.

Various woven and knitted polyester fabrics were pretreated with formulations containing waterborne UV curable resins and silica particles to improve inkjet print quality. The UV curable resins and silica were chosen to impart the affinity of acid dyebased and direct dye-based inks onto the polyester fabrics. The low add-on of the selected formulation was applied to reduce the adverse effect on fabric hand without sacrificing the print quality. A print pattern with various areas and lines in cyan, yellow, magenta and black colors was designed and the pattern was inkjet printed on the various pretreated fabrics with a wide-format inkjet printer (Encad Novajet 750) to investigate the effects of the UV curable pretreatment on the print quality. Experimental results show that improved line quality in terms of the line width gain and the edge raggedness was observed for the lines printed on the pretreated fabrics. In particular, the 2 pt-line width of magenta color on the pretreated taffeta fabric was reduced by 13.8% and the 2 pt-line raggedness of yellow color on the pretreated taffeta fabrics was reduced by 80% compared to that on the untreated fabrics. Generally, increase in silica content inhibits inter-color bleeding onto the adjacent colored areas. For example, a 6% pretreatment formula of 10 parts UV curable resin and 6 parts of the silica particles can yield sharply defined images, while the printed fabrics still maintain a very good hand.

In this keynote the focus is on mapping out the landscape of benefits provided by multi–primary printing and on highlighting some of the major challenges that stand in the way of harnessing its potential. A brief introduction to three and four primary printing and the business needs for multi–primary printing is followed by an enumeration of potential benefits that printing with more than three primaries has. Next some of the key challenges of using larger numbers of primaries are discussed and finally examples are given of future opportunities opened by multi–primary printing.

Inkjet printing of silk fabrics usually uses acid and reactive dye inks. Silk fabrics should be pretreated with sizes before inkjet printing. After inkjet printing silk fabrics need steamed and washed with a large amount of water to remove unfixed dyes. It is not only a long process but also results in a large mount of waste water. Inkjet printing of silk fabrics with pigment inks seems simple and good but bleeding of the printed pattern occurs. This is related to the surface structure of silk fabrics. In order to improve the surface structure of silk fabrics low temperature plasma was used to treat silk fabrics in the atmosphere of oxygen. The surface structure of plasma treated silk fabrics was characterized by AFM (atom force microscopy). And the plasma treated fabrics were printed with a magenta pigment-based ink. The results show that silk fabrics treated with 80 watt power at 50 Pa pressure for 10min had higher color yield and excellent sharpness of pattern. AFM images indicated that plasma treatment produced more grooves on the surface of silk fibers than those untreated. Dynamic contact angle test showed that the hydrophilic property of silk fiber was improved after plasma treatment.