March 2015

First letter from the new editor

Gorazd Golob

Editor-in-Chief

E-mail: gorazd.golob@ntf.uni-lj.si

Welcome to the first issue of the Journal of Print and Media Technology Research created by the new Editorial team. It should be pointed out that it is a transitional issue, as all of the published articles have already been sent in 2014 and the review and editing was done in cooperation with the former Editor-in-Chief Nils Enlund, Executive Editor Mladen Lovreček and other members of the team, who all deserve credit for their contribution to the Journal in the first three years of its existence. On this occasion I would also like to thank them for their trust, as well as for the help and support with publishing this issue of the Journal. I strongly believe that the reinforced Editorial team and the Scientific Advisory Board will continue with their support in this transitional period and in the future.

By taking over the duties of Editor-in-Chief, I accepted the obligation to continue the excellent work of my predecessors. Our goal is for the Journal of Print and Media Technology Research to be considered as the basic form of communication in the interested academic and professional community. I believe we will succeed, with proper support of the interested community of researchers and scientists in the field of printing and media technology, as well as with the support of the editorial board, reviewers, authors and all others who are interested in the publishing of the key Journal in a newly establishing scientific and research field.

My first insights and experience show that we need to work primarily on increasing the prevalence and visibility of the journal. User-friendliness to the authors should be significantly improved by shortening the reviewing and editing time, while maintaining the established high standards of peer-review and editorial process. The contents of the published papers will remain interdisciplinary, covering a wide range of topics, including the traditional print and new interactive media communication, the social impact of modern media, the use of printing technology in the field of
printed electronics, color reproduction, typography, graphic design, packaging and any other advances in related fields.

The journal will also retain the Topicalities section where readers are informed about news and innovations, newly issued publications, textbooks, successfully defended doctoral thesis in our field and important events and activities.

This section is edited by Markéta Držková, Associated Editor, who more than successfully continues the work of her predecessors RaÅ¡a Urbas and Mladen Lovreček. Our intention is that this part of the Journal becomes the key media for communication between academic, research and other advanced and ambitious institutions, researchers and professionals from around the world. Of course, this can only be done with strong community support, therefore you are all invited to join us by providing news from your institutions and research fields, reviews of new publications and other contributions that could be of interest to your colleagues.

With the new website, which will be online soon, the Journal will be able to follow modern trends in communication and become a key connection point for the mutual exchange of information between the members of our publisher, the International Association of Research Organizations for the Information, Media and Graphic Arts Industries – iarigai, and other interested members of the academic, research and professional community.

You and your colleagues are kindly invited to submit papers reporting the highest achievements of your research work, as well as other contributions. We will be happy to increase the volume of the Journal or publish the issues more frequently, should the need arise.

The process of “changing of the guard” as my predecessor Nils Enlund aptly named the transfer of the duty and responsibility to the new editorial team is finished with this first issue in Vol. IV. During editing I have come to new insights, as well as some ideas on how to improve the impact and image of the magazine. Much depends on us who create the Journal, along with our publisher – iarigai, who is kindly supporting our activities. We are all looking forward to following the road to success, recognition and visibility. The criteria for the assessment of our success will be mainly in the quality and number of published papers and their impact on our academic and research community.

Ljubljana, March 2015

JPMTR 053 | 1413 Research paper

DOI 10.14622/JPMTR-1413

Received: 2014-07-15

UDC 6551 : 532.6-035

Accepted: 2014-11-28

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Inkjet printed hydrophobic microfluidic channelling on porous substrates

Risto Koivunen1, Eveliina Jutila1, Patrick Gane1, 2

1 School of Chemical Technology, Aalto University, PL 16400, 00076 Aalto, Finland; Emails: risto.koivunen@aalto.fi Department of Forest Products Technology, eveliina.jutila@aalto.fi

2 Omya International AG, Baslerstrasse 42, CH-4665 Oftringen, Switzerland; E-mail: patrick.gane@omya.com

Abstract

Paperfluidic devices consist of patterned microfluidic channels formed on paper or paper-like material. The direction of surface and bulk liquid flow is typically controlled by patterning hydrophobic barriers on the otherwise hydrophilic paper substrate. A variety of hydrophobic materials and functional printing methods can be used for the patterning. Unlike conventional graphical printing, hydrophobising ink must penetrate the whole depth of the substrate to form an effective barrier against leakage from the channel. This study focuses on the development of solvent-based hydrophobic inks for inkjet printing of microfluidic patterning. Hydrophobic inks were produced by dissolving alkyl ketene dimer (AKD) and poly-styrene (PS) in p-xylene. Hydrophobic test patterns were inkjet printed with these inks on two highly porous filter papers. The AKD-based ink was found to produce effective hydrophobic barriers but suffered from poorly defined borders. The PS-based ink produced well defined borders, but could only penetrate the full depth of the substrate on one of the chosen papers. Adding PS to AKD ink improved jettability. Hydrophobic ink penetration into filter paper was found to take place as surface film flow over the skeletal fibre structure of the paper. Therefore, paper fibre surface properties and ink surface tension and viscosity are considered to play controlling roles in determining the penetration depth. Differences seen with respect to aqueous wicking behaviour at the interface/border between hydrophilic and hydrophobic regions might be due to the Marangoni derived coffee stain effect and likely to interactions with the fibre surfaces.

Keywords: functional printing, hydrophobic ink, polystyrene, alkyl ketene dimer, paperfluidics

JPMTR 054 | 1442 Research paper

DOI 10.14622/JPMTR-1442

Received: 2014-11-25

UDC 655 : 621.38

Accepted: 2015-02-13

Improving conductivity of rotary screen printed microparticle silver conductors using a roll-to-roll calendering process

Elina Jansson1, Jukka Hast1, Jarno Petäjä1, Jorma Honkala2, Juha Häkkinen2, Olli-Heikki Huttunen1

1 Printed and Hybrid Functionalities research area, VTT Technical Research Centre of Finland, P.O. Box 1100, 90571 Oulu, Finland; E-mail: jukka.hast@vtt.fi

2 Optoelectronics and measurement techniques laboratory, University of Oulu, P.O. Box 4500, 90014 University of Oulu, Finland

Abstract

A roll-to-roll (R2R) calendering process was developed and used to improve the conductivity of rotary screen printed microparticle silver conductors. Two commercial microparticle silver pastes were used. In the calendering process, the rotary screen printed microparticle silver conductors are compressed under pressure and heat in order to make the porous microparticle layer denser and flatter. The results show that the resistivity of the rotary screen printed microparticle silver conductors was dramatically dropped after the R2R calendering process by 29-56 % depending on the silver paste. The complete drying of the calendered conductor layer decreased the resistivity even further as a result of which the layer resistivity was decreased 74 % from its initial value. The roughness of the silver conductors was also reduced remarkably after the calendering by 45-72 %. The effect of the R2R calendering process on the printed inductively remote reada- ble capacitive moisture sensor based on simple inductor-conductor resonant circuit was also demonstrated. Calendering improved the Q-factor of the sensor but decreased the resonance frequency.

Keywords: rotary screen printing, calendering, microparticle silver, printed conductor, roll-to-roll printing

JPMTR 055 | 1428 Research paper

DOI 10.14622/JPMTR-1428

Received: 2014-07-15

UDC 621.798-035.67+1k-02

Accepted: 2014-11-24

Study of the effects of the ink layer on selected properties of multilayer packaging films

Joanna Izdebska, Zuzanna Żołek-Tryznowska, Magdalena Wirtek

Warsaw University of Technology, Faculty of Production Engineering, Institute of Mechanics and Printing, Department of Printing Technology Konwiktorska 2, 00-217 Warsaw, Poland; E-mail: j.izdebska@wip.pw.edu.pl

Abstract

Application of multilayer films in packaging allows the reduction of the average weight of packaging and a selection of its optimal barrier properties. This kind of material is particularly important for the development of packaging. The aim of this research was to determine the influence of the ink layer thickness on the mechanical properties of interlayer printed laminates. Studies were performed for a double-layer film (poly(ethylene terephthalate)/glue/biaxially oriented polypro pylene) prepared by an adhesive method using a two-component, solvent-free adhesive. The bond strength of the lami- nates and the thickness of each layer were measured. It was found that the thickness of the fixed ink, interlayer printed on the reverse side of the PET film, has a significant influence on the mechanical properties of the laminates. Regardless of the ink film thickness, the values of the bond strengths of the printed laminate are significantly reduced.

Keywords: laminate, double-layer film, interlayer printing, bond strength

JPMTR 056 | 1420 Research paper

DOI 10.14622/JPMTR-1420

Received: 2014-07-15

UDC 159.937 (084) 621.798

Accepted: 2015-02-13

Visual perception and recollection of pictures in packaging design

Ulrich Nikolaus and Sandra Bendlin

Leipzig University of Applied Sciences (HTWK Leipzig), Faculty of Media, Gustav-Freytag-Straße 42, 04277 Leipzig, Germany; E-mail: ulrich.nikolaus@htwk-leipzig.de

Abstract

Continuing an ongoing study to analyze consumer reactions to packaging design, eye tracking test results that explore the visual perception and recollection of pictures in packaging design are presented. Particularly, the extent and reliability of human recollection of pictorial elements on packages that were seen only for a short period of time is discussed in detail. These results help to better understand the visual impact which pictures in packaging design have on consumers. The results suggest that consumers discern a great deal of graphical detail in pictures within a very short period of time, but that this recollection varies among users and is sometimes inaccurate. Furthermore, it could be shown that viewers in general describe coherent (albeit sometimes inaccurate) interpretations of visual stimuli instead of isolated details of visual design.

Keywords: packaging design, eye tracking, qualitative content analysis, visual perception, picture
JPMTR 1411 Professional communication

DOI 10.14622/JPMTR-1411

Received: 2014-07-04

UDC 655.1 : 762-035.67 | 66-97

Accepted: 2014-12-06

Analysis of the thermal behavior of gravure inks: comparing experimental results and numerical methods

Shilpi Naskar, Kanai Chandra Paul, Arun Kiran Pal

Department of Printing Engineering, Jadavpur University, Salt Lake Campus, Block-LB, Plot-8, Sector-III, Salt Lake, Kolkata IN-700098, West Bengal, India; E-mails: shilpinaskar@gmail.com; kanaipal@yahoo.com; arunkiranpal@yahoo.co.in

Abstract

Gravure inks are frequently applied in multiple layers as prints on packaging material. Besides giving some information about the product, the printed ink film can be used also for protection. The compound printed layer of different colored gravure inks (of equal thickness) plays an important role in protecting the product contained within the package from external atmospheric conditions. For example, heat transfer either from the outside or the inside of the package can be controlled by a properly designed ink film combination on the package. The color inks generally used are specialty white, standard yellow, magenta and cyan, together with black, applied consecutively. If these ink coatings are not long-lasting, or the system is not properly designed, this may lead to failure to protect the packaged product due to unwanted transfer. In the present investigation, the thermal properties of free films of different colored inks were measured individually and also in combination to assist in the design of appropriate ink layers on packaging leading to extended shelf-life for the product. The measured thermal properties are thermal conductivity, specific heat and the coefficient of linear expansion. Further, the thermal contact resistances of different color combinations, contact surface temperatures and thermal stress developed in the coating were determined using an algebraic method. A finite element method was also adopted for determining the contact surface temperature and thermal stresses developed. These numerical results were compared with the expe- rimental findings. It was found that the heat transfer rate either from the package or from the outside will be much lower if the thicknesses of all the ink layers are equal. Also, it is proposed that if the coatings of inks are printed in the order of WKCMY, the protection of the product will be optimal.

Keywords: coating, coefficient of linear expansion, thermal conductivity, specific heat, contact thermal resistance

JPMTR 1439 Professional communication

DOI 10.14622/JPMTR-1439

Received: 2014-10-06

UDC 655.1 : 763-035.4 (084)

Accepted: 2015-02-04

Evaluation of misregister on multiple coated fine papers in sheet fed offset printing

Wolfgang Pacher1,2, Franz Frisch2, Peter Wolfgang Fuchs2, Wolfgang Bauer1

1 Institute of Paper, Pulp and Fiber Technology, Graz University of Technology, Austria; E-mail: wolfgang.bauer@tugraz.at

2 Sappi Papier Holding GmbH, Gratkorn, Austria; E-mails: wolfgang.pacher@sappi.com; franz.frisch@sappi.com; peterwolfgang.fuchs@sappi.com

Abstract

Misregistration is one of the most common printing faults of wood free multiple coated fine papers in multicolor sheet- fed offset printing. Misregister significantly reduces print quality and leads to complaints to the paper manufacturer. Unfortunately it is often difficult to identify the cause of a misregister problem, because apart from the potential paper impacts, several printing machine and printing ink parameters may also have an effect. It would therefore be an advantage
– especially for the paper manufacturer – to be able to determine and influence the factors leading to this problem. In practice a qualitative evaluation of misregister is frequently carried out using a printer’s loupe, which is a quite subjective method and has the disadvantage of a rather low resolution. Evaluation of misregistrations using a light microscope allows higher resolution but is quite time consuming.

Therefore, a new offline measuring device for fast and objective evaluation of misregistrations was developed in the R&D department of Sappi Gratkorn. First results using this device show the expected relationships between misregistration and ratio of machine/cross direction fiber orientation, influence of grain direction and filler content of the base paper. Furthermore, misregister was found to be dependent on the amount of fountain solution as well as on the smoothness of the rubber blankets.

Keywords: misregister, sheetfed offset printing, machine/cross direction ratio, fiber orientation, filler content, fountain solution