September 2015

A letter from the Editor

Gorazd Golob

Editor-in-Chief

E-mail: gorazd.golob@jpmtr.org/journal@iarigai.org

50 years of iarigai

iarigai – The International Association of Research Organizations for the Information, Media and Graphic Arts Industries – is celebrating half of the century of successful and fruitful existence. More than 30 years before formally establishing the iarigai in 1965, cooperation in common projects, exchanges of ideas and information, presentation of the results of research work was supported by graphic arts research and professional institutes and organizations from Denmark, France, Holland, Germany, Sweden and Great Britain. Today iarigai is a strong international association with 44 members from 23 countries.

History of iarigai was as interesting as it was dynamic. First informal and formal research conferences extended to biennial management conferences and symposia on different topics. Research activities, oriented mainly into conventional printing technology, colour reproduction challenges and interactions between paper and ink, evolved, in the past decades, into communication and multimedia issues, printed functionality, printed electronics and all other topics, recognized as our interdisciplinary research field.

During the first conferences the scientific book Advances in Printing and Media Technology (previously Advances in Printing Science and Technology) became the main publication for dissemination of the results of scientific and research work. In past years the leading role of the Advances has been transferred to the Journal of Print and Media Technology Research. With this decision the print and media research community, gathered under iarigai, made a great step forward to the recognition comparable with other scientific disciplines.

50th anniversary celebration of iarigai took place in Finland, where the association was founded, in the pleasant and working atmosphere at the 42nd International research conference of iarigai. The conference overlapped with meet- ing of COST Action FP1104 New possibilities for print media and packaging – combining print with digital (EU supported project), giving added value to the common event. All authors, who have successfully participated at the conference and COST event, are kindly asked/invited to extend and improve their conference contributions into full scientific or research papers for publication in the Journal. Every manuscript will be double-blind peer reviewed and edited under well-established standard procedure.

In the present issue, six original scientific and research papers are published with interesting content from theoretical study of hydrodynamics of inks in the flexographic printing unit, following with reports of the research of functional printing, where authors respond to the challenges in medical diagnostics, pharmacy and smart packaging, continuing with solving of sustainability problems with soy based inks, following with investigation of counterfeiting at 2D codes and research of contemporary media and their impact on the end user. This selection again demonstrates the breadth of our research areas and multidisciplinary approach. I am convinced that these topics will be of great interest to you, our readers.

In the “Topicalities section”, edited by the Associate Editor Markéta Držkova (marketa.drzkova@jpmtr.org), we are again bringing you an overview of new published books, three short abstracts from Doctoral thesis, defended at the University of Oslo, the KTH Royal Institute of Technology Stockholm and from the Loughborough University, and an overview on news and events that might be interesting for our readers.

We are continuously expecting news from your institutions, your partners from other academic or research institutions from other countries and from the industry, to open new paths for dissemination of our achievements and to find new opportunities for future cooperation and common international research projects. At this occasion, I would like to point out, that the primary role of the Journal is, and will remain also in the future, the publishing and dissemination of the scientific, research and technical papers where most important and valuable results, comments and conclusions are presented.

At the final page you will find invitation to the Evolutions in food packaging printing, an international network meet- ing, organized by iarigai and vigc in Brussels in November. This kind of events are important as a meeting point for the scientists, professionals and decision makers from the academic and research institutions and from the industry, who are looking for the new way of cooperation in the future. Next important event in 2016 will be iarigai International research conference in Toronto.

Ljubljana, September 2015

JPMTR 063 | 1426 Original scientific paper

DOI 10.14622/JPMTR-1426

UDC 655 : 681.6 (532.5)

Received: 2014-07-15

Accepted: 2015-09-10

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Lubrication theory of ink hydrodynamics in the flexographic printing nip

Hans Martin Sauer, Dominik Daume, Edgar Dörsam

E-mail: sauer@idd.tu-darmstadt.de

Institute of Printing Science and Technology (IDD), Technische Universität Darmstadt, Magdalenenstraße 2, D-64289 Darmstadt

Abstract

On the base of hydrodynamical lubrication theory, we develop a mathematical model for the ink transfer in a flexographic printing process. When using the specific parameter ranges the model may also be applicable to the offset process. Specifically, we show how our model can be applied to viscous ink flows in the printing nip in presence of elastic printing plates, and how this sets limits to the possible resolution of the printing image. We also discuss the structure of the contact zone between printing plate and the substrate which is determined by the viscous and elastic stresses within the ink layer and the printing form. We also estimate the dynamic pressure profile in the ink during the transfer process. Finally, we discuss the phenomenon of ink seam formation at the rim of a flexographic printed pattern, and viscous finger formation. Explicitly, we show that important parameters, such as the width of an ink seam, the actual nip height, the size of the contact zone, and the ink shear, scale nonlinearly with printing speed. We derive the respective scaling exponents and compare the predictions with printing experiments.

Keywords: flexography, lubrication theory, ink viscosity, ink splitting, viscous fingering

JPMTR 064 | 1419 Research paper

DOI 10.14622/JPMTR-1419

UDC 667.6 : 676.2

Received: 2014-07-15

Accepted: 2015-08-28

Effect of coating pigment, binder type and binder amount on planar liquid wicking on coated substrates

Eveliina Jutila1, Risto Koivunen1, Patrick A. C. Gane1,2

E-mails: eveliina.jutila@aalto.fi; risto.koivunen@aalto.fi; patrick.gane@omya.com

1 School of Chemical Technology, Department of Forest Products Technology, Aalto University, PL 16400, 00076 Aalto, Finland

2 Omya International AG, Baslerstrasse 42, CH-4665 Oftringen, Switzerland

Abstract

This study focuses on the development of highly wicking coated substrates for microfluidic devices with enhanced resolution compared to current filter paper-based devices. Four highly absorbing pigments, fumed silica (FS), modified calcium carbonate (MCC), natural diatomite (ND) and flux-calcined diatomite (FCD), as well as three binders, styrene-acrylate (SA) latex, polyvinyl alcohol (PVOH) and carboxymethyl cellulose (CMC), were used to form coating structures with different wicking properties. Studies include characterisation of the pigment particles and thin layer wicking (TLW) experiments, in which wicking height of liquid in coatings is measured as a function of time. The results show that the choice of coating pigment and binder as well as the binder amount has a significant effect on wicking characteristics of a coating. The introduction of diatomite pigments into blends with MCC improved the wicking capabilities of the coating, especially in the case of ND. Latex was found to inhibit wicking of liquid the least, followed by PVOH and CMC. Increased binder amounts reduce wicking due to reduced pore connectivity and binder-filled pores. It was found that the wicking resistance of pigment alone is too high for rapid analysis over long distances in thick coatings. Once optimised for binder type and amount, these coating structures could be utilised as high resolution microfluidic analysis elements, i.e. test cells, incorporated either into a wicking channel matrix or placed at junctions of microfluidic channels derived from controlled hydrophobic/oleophobic printing or designed shrinkage fracture geometries.

Keywords: microfluidic device, absorbent coating, microdiagnostics, hydrophilic channel, printed functionality

JPMTR 065 | 1443 Research paper

DOI 10.14622/JPMTR-1443

UDC 655 : 621.798

Received: 2014-12-09

Accepted: 2015-09-01

Formation and photoluminescent properties of nanophotonic elements with nanosized ZnO for smart packaging, deposited by screen printing

Olha Sarapulova, Valentyn Sherstiuk

E-mails: olhasarapulova@gmail.com; sherstyukv@ukr.net

National Technical University of Ukraine, Kyiv Polytechnic Institute, Institute of Publishing and Printing, 03056, Ukraine, Kyiv, 1/37 Yangel Str.

Abstract

Smart food packaging (active and intelligent packaging), which indicates and/or prevents changes in the packaged food product, traces the history of its storage etc., is becoming more popular due to the fact that it enhances safety of packaged food storage, transportation and consumption. It is convenient to use printing techniques to produce active elements of smart packaging, including the elements which respond to the changes in packaged food, which occur as the result of food spoilage or aging. However, issues concerning technological aspects arise when the compositions are printed onto materials such as paper or polymer films, especially if these compositions contain functional nanoparticles with luminescent properties. There has been conducted technological research of formation of luminescent coatings containing nano-sized ZnO, for active and intelligent packaging, using screen printing. Photoluminescent properties of the obtained nanopho- tonic elements are studied and the factors that affect their properties are defined. It was determined that by manipulating coating thickness, molecular weight of the polymer and the concentration of nanophotonic component in the composition it is possible to increase photoluminescent intensity of the screen-printed coatings and obtain different colors of photoluminescence.

Keywords: screen printing, nanophotonics, photoluminescence, nanomaterial, zinc oxide

JPMTR 066 | 1415 Research paper

DOI 10.14622/JPMTR-1415

UDC 582.763 : 667.5

Received: 2014-07-15

Accepted: 2015-08-19

Formulation of drop on demand soy inkjet inks

Alexandra Pekarovicova, Zahra Mashhadi Khodabakhsh, Paul D. Fleming III

E-mail: a.pekarovicova@wmich.edu

Western Michigan University, Center for Ink and Printability, 4601 Campus Drive, A-213 Parkview, Kalamazoo, MI 49008-5462, USA

Abstract

Soy protein has a complex 3-D shape and contains 19 different amino acids, which are held together in a coiled structure by peptide bonds. The basic application of industrial-grade soy protein is for a use as a binder in paper coatings. In this work, soy polymer Pro-Cote 4610E was used for formulation of drop on demand piezoelectric inkjet inks. Soy drop on demand inks performance was compared to ones of inks formulated with acrylic polymer Joncryl 678 and commercial inkjet ink. During formulation, sodium hydroxide was more successful in solubilizing of soy polymer than ammonium hydroxide. Preliminary soy ink formulations were made, and based on these results, a design of experiments (DOE) was carried out to optimize ink formulations. The DOE was executed with another aim to compare soy and acrylic based chemistry performance. A combination measure of ink density, surface tension and viscosity was used to assess inkjet printability. Drop behavior was controlled by Reynolds, Weber and Ohnesorge numbers. Reciprocal value of Ohnesorge number (Z number) was calculated, and used for prediction of soy protein inks and acrylic inks jettability. The print design for Dimatix Material Printer DMP-2800 consisted of solid patches and lines of varied width and orientation. At first, even inks with proper Z number were creating satellite drops and were puddling, which was removed by increasing the drop velocity from 0.2 m ∙ s−1 to around 4 m ∙ s−1. Thus, it was found that higher voltage is crucial for proper drop formation. The quality of printed lines was evaluated by measuring their width and raggedness using image analysis. Print mottle was evaluated on solid patches. All inks, soy, acrylic and commercial, exhibited printed line widths greater than their nominal widths, which was expected, due to printing on plain inkjet paper. There were no significant differences in quality of print lines between soy and acrylic inks and commercial ink. Soy ink achieved the best print uniformity of solids, when compared to formulated acrylic or commercial inkjet ink.

Keywords: soy polymer, acrylic ink, ink formulation, jetting, Z number

JPMTR 067 | 1430 Research paper

DOI 10.14622/JPMTR-1430

UDC 003.29 : 004.93/7.061

Received: 2014-07-30

Accepted: 2015-07-26

Image analysis as a tool to discriminate counterfeit from true 2D printed codes

Nadège Reverdy-Bruas, Lionel Chagas, Jean-Pascal Poletti, Raphaël Passas

E-mail: nadege.reverdy@pagora.grenoble-inp.fr; lionel.chagas@pagora.grenoble-inp.fr

Univ. Grenoble Alpes, LGP2, F-38000 Grenoble, France CNRS, LGP2, F-38000 Grenoble, France Agefpi, LGP2, F-38000 Grenoble, France

Abstract

The general context of this study is to establish recommendations for the development of digital models in the framework of counterfeiting. To achieve this goal, printed 2D codes were investigated. Visual Basic tools have been developed in order to automate tasks. The present paper allows characterizing the printing process used (conventional and waterless offset); sensitive results were also obtained regarding the kind of printed substrate (coated and uncoated paper). Histograms of area classes were plotted and they revealed that the printing process induced the raise of a new class of small dots not present on the digital file. In addition, two types of counterfeiting methods were carried out and they pointed out that the histograms of the counterfeit codes were different from the original printed code, whatever the attempt of counterfeiting. Furthermore, in these cases, small dots tend to agglomerate and form new area classes of bigger size. The method developed in this study thus allows the identification of the printing process as well as the distinction of true and counterfeit 2D codes.

Keywords: 2D codes, counterfeiting, security, automation, image analysis

JPMTR 068 | 1431 Research paper

DOI 10.14622/JPMTR-1431

UDC 001.92 : 659.3

Received: 2014-07-30

Accepted: 2015-08-18

Investigating the effects of publishing approaches using print, electronic and augmented reality media on user experience

Elena Fedorovskaya, Lufei Yu

E-mail: eafppr@rit.edu; lxy4140@rit.edu

Rochester Institute of Technology, Rochester, NY 14623, USA

Abstract

To evaluate the potential role of modern augmented reality (AR) technology in publishing and its usefulness for interactive print, we conducted a study where we investigated the influence of different methods of presenting content on the users’ story reading experience. The stories were produced in print and electronic media, with and without augmented reality component, using a multi-media setup consisting of a computer with the monitor display, a smartphone, and a printed material. A 2 × 2 within-subjects experimental design was implemented (2 levels of medium: print and electronic; and 2 levels of augmentation with video clips: yes or no), wherein 32 participants aged 18–29 years old were asked to read short stories produced with different publishing methods and evaluate their preferences for the presentation of the content, as well as interestingness, comprehension and overall experience with the stories on a 7 point scale using a questionnaire. AR and the medium–AR interaction were found to be significant in determining the preference for the publishing method. The paper–AR combination had the highest score among all the methods and was rated statistically different from the paper only version, which, in turn, had the lowest score. For the overal expeirence ratings a significant medium-AR interaction was observed, with the trend, similar to the publishing preference ratings. Overall experience was linked to the users’ preference ratings for the publishing methods, interestingness and enjoyment of the stories, and the ease of understanding the story line. The results indicate that AR enhances user experience, particularly with print media, making it on par or even higher valued than commonly used electronic media. In contrast, the traditional print version without augmentation was least preferred.

Keywords: publishing, augmented reality, print, digital media, storytelling