An investigation into the effects of solvent content on the image quality and stability of ink jet digital prints under varied storage conditions

Increasing numbers of galleries, museums and archives are including ink jet printed materials into their collections, and therefore displays. There is evidence that the instability of these prints is such that images can suffer deterioration in print quality or in extreme cases, a loss of information over an extended period of time. This is shorter than the period typically required for perceptible deterioration to occur in many other paper-based artworks. The image stability of prints is affected by a number of factors some of which have already been studied. However the role played by the ink solvent in the loss of image quality has yet to be explored. This paper will outline research being undertaken to investigate the effects of solvent content which may increase/promote the loss in image quality of the hard copy prints when stored or displayed under a range of temperature and humidity conditions

Studies on fastness properties of ink jet prints on coated papers

Novel low-cost coatings intended for ink jet printing have been developed recently. Studies on their print quality have mainly focused on the optical and geometrical properties of the image, whereas their effect on long-term print quality has been largely ignored. The objectives of this thesis were to evaluate the applicability of vibrational spectroscopic methods for studying ink jet prints and to clarify the mechanisms contributing to the permanence of small-scale ink jet prints on coated papers. Light and water fastness in the time-scale of the print's end use were of particular interest. These were studied using experimental inks and coatings with known compositions. The first part of the study concerned the applicability of vibrational spectroscopic methods for studying ink jet prints. According to the results, differences between the samples originating from changes in exposure to light could be detected with both FTIR and Raman spectroscopy. The most suitable techniques were the FTIR-ATR, confocal NIR-Raman, UV resonance Raman and Kerr gated resonance Raman methods. The second part of the thesis detailed the issues related to the mechanisms contributing to print permanence. The results suggested that the light and water fastness of ink jet prints were affected by both the physical properties of the coatings and the chemical paper-ink interactions. The latter played the dominant role, whereas the significance of physical paper properties depended on the type of ink and the coating. As a rule, the stronger the chemical paper-ink interactions were, the less relevance the physical properties of the coating had. Results also indicated that light and water fastness could be markedly influenced by the type of colorant, but also by choosing the right coating ingredients.reviewe

An investigation of the performance of photochromic dyes and their application to polyester and cotton fabrics

Six commercial photochromic dyes were applied to polyester and, to a lesser extent, cotton fabrics by different dyeing and printing methods. The photochromic performance of the dyed and printed fabrics was investigated in terms of the degree of photocoloration, background colour, fading characteristics, fatigue resistance and storage stability. A traditional aqueous-based disperse dyeing method was used to apply the photochromic dyes to polyester fabric. Solvent-based dyeing methods also were investigated for application of the photochromic dyes to polyester fabric. Solvent-based inks were formulated and applied to polyester and cotton fabrics by digital inkjet printing. The photochromic performance and colour fastness to light and washing of the photochromic fabrics were evaluated and comparison made. UV/visible spectra of the commercial photochromic dyes in a range of solvents were obtained and interpreted in terms of solvent polarity. On the basis of this study, the photochromic performance of the fabrics was improved by selecting the appropriate application solvents which transferred minimum background colours onto the fabrics. A new method of evaluating lightfastness of photochromic fabrics was established, aimed at replacing the conventional method by an instrumental method. This method was based on comparing the decrease in the degree of photocoloration of photochromic fabrics after light exposure with measured values of the colour differences of the blue wool references after fixed periods of light exposure. Two photochromic dyes were synthesized by azo coupling of a spironaphtho[2,1-b]oxazine with diazonium salts obtained from p-nitroaniline, and m-nitroaniline. Molecular modeling of the new photochromic systems, which are referred to as azospirooxazine dyes, showed that the dyes were predicted to have the potential to show photochromism. Thus, the photochromism of the azospirooxazine dyes in a range of solvents was investigated. The investigations showed that the dyes performed differently in different solvents in terms of the hue, the rate of the photochromic colour change and the colour reversibility

An entrepreneurial framework for deciding on the implementation of large format digital printing internationally

This study focuses on entrepreneurs within the SME sector using large format digital printing (LFDP) because of the changes in technology that influences the decisionmaking processes of the entrepreneur in the purchasing of a new LFDP. These fast changes are likely to continue and can cause technologies to become obsolete overnight. The entrepreneurs within the LFDP industry find themselves in the midst of these fast changes and are faced with a dilemma. On the one hand, they need to make sure that the technology used produces consistent and quality products. On the other hand, the entrepreneur needs to ensure an optimal return on investments. From the literature and the findings of the study, the researcher recommends a change to an existing model on a consultant involvement purchase of high technology products, which is then adapted to integrate resource-forecasting areas together with timing and type of information required as well as external environment scanning. The existing model’s focus is on the individual’s ability to make decisions based on their own knowledge. However, by integrating technology forecasting components, and scanning the business environment and resource forecasting needed the decision-maker will be better equipped to make decisions that also takes into account the external environment. This will also allow them to plan and manage growth in a systematic way. Therefore the proposed model takes into account individual capabilities and technology forecasting components that can facilitate the decision-making process. The adapted model on decision-making clearly delineates that the combination of entrepreneurial qualities and technology forecasting techniques in the LFDP industry will ultimately assist the entrepreneur on various levels in deciding on a new LFDP

Novel patterning techniques for manufacturing organic and nanostructured electronics

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.Page 206 blank.Includes bibliographical references.Molecular organic semiconductors and nanometer size particles are two new classes of functional materials allowing fabrication of electronic devices on low-cost and large area substrates. Patterning these electronic materials requires the development of unconventional techniques, and the scientific understanding behind the manufacture processes. We introduce the first-generation Molecular Jet (MoJet) printing technique for vacuum deposition of evaporated thin films and apply it to the fabrication of high-resolution pixelated (800 ppi) molecular organic light emitting devices (OLEDs) based on aluminum tris(8-hydroxyquinoline) (Alq3), and the fabrication of pentacene based organic field effect transistors (OFETs) with narrow channel (15 gm) and asymmetric silver/gold contacts. Patterned printing of both organic and metal films is demonstrated, with the operating properties of MoJet-printed OLEDs and OFETs shown to be comparable with the performance of devices fabricated by conventional evaporative deposition through a metal stencil. This MoJet printing technique is reconfigurable for digital fabrication of arbitrary patterns with multiple material sets and a high print accuracy of better than 5gtm, and scalable to large area substrates.(cont.) Analogous to the concept of "drop-on-demand" in Inkjet printing technology, MoJet printing is a "flux-on-demand" process and we show it capable of fabricating multi-layer stacked film structures, as needed for engineered organic devices. We present the concept and the applications of the second-generation MoJet printing technique. Using this technique, we demonstrate patterned molecular organic semiconducting thin films directly printed by a three-step local evaporative deposition, in conjunction with using the HP thermal InkJet printing technology. This MoJet printing technique can be applied to pattern solution-processable molecular organic thin films, providing flux-on-demand in an ambient environment. We develop an Inkjet assisted micro-contact printing technique for the patterning of colloidal semiconductor nanoparticles. Active OLEDs incorporated with a uniform thickness layer of colloidal nanoparticles are fabricated by using this Inkjet printing plus stamp transferring technique. The material usage efficiency is largely boosted. To our knowledge, these three novel patterning techniques presented in this study provide for the first time unprecedented capabilities for manufacturing organic and nanostructured electronic devices.by Jianglong Chen.Ph.D

The development of methods for the reproduction in continuous tone of digitally printed colour artworks

Advances in printing technologies in the late 19th century led to the development of half-toning techniques enabling the economical reproduction of photographic images in print. Whilst undoubtedly successful in low cost high volume image reproduction, half-toning representations are less faithful in detail when compared to continuous tone photomechanical methods in use at that time. This thesis asks the question: can the creative application of 21st century digital fabrication technologies enable the qualities of continuous tone imaging to be regained? In the 21st-century, printmaking may be seen as the interchange of ideas, experimental practice and interdisciplinary thinking. Printmaking has always been a means of combining modern technology and methods with existing traditional and commercial imaging processes. Technological advancement in print however does not always provide a finer quality of print. Qualities often attributed to pre-digital continuous tone printing can be lost in the transition to a digital half tone print workflow. This research project examines a near obsolete 19th century print process, the continuous tone Woodburytype, developed to address the issue of permanence in photography. Through a methodological approach analyses of the Woodburytype an empirical reconstruction of the process provides a comprehensive critique of its method. The Woodburytype’s surface qualities are not found in other photomechanical printing methods capable of rendering finely detailed photographic images. Its method of image translation results in the printed tonal range being directly proportional to the deposition thickness of the printing ink, however it never successfully developed into a colour process. By examining and evaluating digital imaging technology this study identifies, current computer aided design and manufacturing techniques and extends upon known models of Woodburytype printing through the development of this deposition height quality enabling a new digital polychromatic colour printing process