September 2016

A letter from the editor

Gorazd Golob

Editor-in-Chief

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

We are back again with a regular issue of the Journal.

The second issue of 2016 was released as the Special edition: Audience, design, technology and business factors in new media innovation, edited by the guest editors David M. Frohlich & John Mills. On this occasion I would like to thank them for their efforts and excellent work done. They have attracted a number of authors and reviewers who researched in the field of media innovation and strengthened the position of the Journal in this segment.

The present issue is again very multidisciplinary, which is becoming the standard and most recognizable feature of the publication. There are four scientific contributions and one professional paper. The first scientific paper from the field of ecological and economic advantages of UV varnishing is of specific interest, because of the fresh approach that goes beyond the purely technical aspects of the processing of printed matter. It shows us the potential for improvement in the printing process from different point of view, taking into consideration rationalization of the energy and material consumption while reaching the same visual effect for the end user. The second contribution is dealing with aerosol printing technique, lesser known to many experts of printing, where the possibility of significant improvement in process stability and equalizing the print quality even in long term operation is shown. New approach in colour proofing with the use of optical brightening agents in an experimental inkjet printing, with a goal to equalize the quality of color reproduction printed on special proof papers with low content of optical brighteners in comparison to commercial papers with different, usually greater amount of optical brightening agents, is presented in the next research paper. Presentation of the models and methods for compensation of chromatic ink colors with black ink by using various techniques represents the fourth article. This content is complemented by the last article where the possibility of using less-known acoustic wave sensor for the measurement and regulation of ink viscosity in gravure printing system is presented, with the evidence of its suitability for use in practice.

Two of the published papers are based on the contributions of last year’s International Research Conference of iarigai in Helsinki, but one paper is even from this year’s Conference, held in August in Toronto. The authors of the latter, A. Wadhva, D. Cormier and S. Williams, and reviewers involved, deserve special recognition for their effort, quick response and efficiency during reviewing and editorial process. It is important to emphasize that papers accepted for publication are significantly upgraded and extended, comparing to the Conference contributions and already published extended abstracts from the same authors, on the same or similar content.

Associated Editor Markéta Držková (marketa.drzkova@jpmtr.org) again prepared Topicalities including news from the field, overview of published books, outstanding doctoral dissertations in recent time, and events, congresses and workshops of interest to readers of this Journal. Her comment on the content of Color Encyclopedia of Science and Technology drew my attention. Colour printing area is covered only partially, also reflecting the wider (non)visibility and (non)recognition of scientific and research fields covered by JPMTR, where publication of the research results in the field of retrieving, processing, reproduction (including printing and displaying) and colour perception is relatively well represented.

Again, I would like to invite ambitious authors and reviewers who intend to contribute and participate in the creation of the Journal and developing our research field. According to the quality and high level of presentations and publications of contributions at the Conferences organized by the members of iarigai, a lot of interesting posts are expected. This is supported also by the wealth of related research topics elaborated in dissertations; each one presented in JPMTR is freely accessible online or when requested from the author, and of course there are a great number of those which were not reported in the Journal (as the space is limited) but still may be of interest for many readers, and their authors contribute to the development in the field. With quality of published papers we gain the recognition from our colleagues and justify the existence of our interdisciplinary but often unnoticed research area.

Ljubljana, September 2016

JPMTR 084 | 1609 Original scientific paper

DOI 10.14622/JPMTR-1609

UDC 655.1 | 338.3-035.67-022.316

Received: 2016-06-04

Accepted: 2016-09-07

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3-16

 

A model of sustainable production: ecological and economic benefits of high-gloss UV-coating in offset printing without a relevant loss in gloss quality

Kirsten Radermacher

E-mail: k.radermacher@outlook.com

Erbschloeer Strasse 22, D-42369 Wuppertal, Germany

Abstract

This paper presents a guideline for enterprises to realize sustainable production in compliance to economic interests. A special perspective on the product quality that is perceptually noticeable, or required for customer satisfaction, enables to reach economic benefits not conflicting in respect with the principles of sustainability. Therefore, the model of sustainable production was exemplarily demonstrated by the glossiness of cardboard packaging. The investigation was mainly concentrated on the gloss measurement and perception aiming to define a threshold of perceptual gloss that gives information about the product quality required. Gloss has been a part of research work for decades. However, there are no researchers known who were able to quantify a threshold that inform about noticeable gloss differences. Furthermore, the measurement technology of gloss is much more complex than expected. The specular gloss is still the main important feature, and is broadly the essential measure in practical application. However, further gloss types are implemented in so-called goniophotometric instruments. In this paper, the currently available knowledge in gloss perception and measurement is used to generate a measure of perceptible gloss differences. Influencing factors affecting the environmental performance of high-gloss cardboard packages are presented, and suitable methods for measurement are employed. For high-gloss coated cardboard packaging, the volume of the coating roller and the intensity of the UV-curing unit reveal potential for sustainable production under consideration of the threshold of 2.0 Gloss Units that is recommended from a visual test performed. Considering the assumption made for the product example, 0.99 ± 0.65 g ∙ m−2 of UV-coating and 6.6 ± 3.8 kWh of energy could be saved. The integration of these scenarios in life cycle assessment (LCA) on coatings will help to assume whether these savings are crucial in the whole product life cycle. This paper gives first impressions.

Keywords: gloss measurement, gloss perception, ecological assessment, cardboard packaging, quality assessment

JPMTR 085 | 1610 Research paper

DOI 10.14622/JPMTR-1610

UDC 655.1 | 62-1/-9

Received: 2016-06-05

Accepted: 2016-09-10

Improving run-time stability with aerosol jet printing using a solvent add-back bubbler

Arjun Wadhwa1, Denis Cormier2, Scott Williams3

1 Quest Integrated, LLC, 19823 58th Pl. South, Suite 200, Kent, WA 98032 (USA); E-mail: a.wadhwa@qi2.com

2 Industrial and System Engineering, Rochester Institute of Technology, 81 Lomb Memorial Drive, Rochester, NY 14623 (USA); E-mail: drceie@rit.edu

3 School of Chemistry and Materials Science, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623 (USA); E-mail: sawppr@rit.edu

Abstract

Aerosol jet printing is a non-contact process capable of printing on conformal and flexible surfaces. Aqueous or solvent nano-inks are pneumatically atomized under nitrogen. The atomizing gas flow through the atomization cup leads to evaporation and removal of volatile solvent(s). As the ink solid loading fraction increases with the loss of solvent during atomization, the rheological changes eventually lead to instabilities in print output. A potential solution to this problem is to moisten the incoming atomizing gas with a solvent add-back system. In this study, neat co-solvent solutions of ethanol and ethylene glycol at 85 : 15 and 30 : 70 mixing ratios were atomized using nitrogen flow rates ranging from 600 to 1000 cm3 ∙ min−1 (ccm, cubic centimeters per minute). It was observed that ethanol, being the more volatile solvent, was depleted from the neat solution at a much higher rate than ethylene glycol. When nitrogen gas was passed through a bubbler prior to atomization, an excessive amount of ethanol was returned to the neat solution. The solvent loss rate from an ethanol rich neat solution (80 %) was higher compared to an ethylene glycol rich neat solution. Perfecting the solvent add-back rate to an ink will enable longer print runs in a manufacturing environment.

Keywords: aerosol jet printing, direct write, ink stability, solvent evaporation rate

JPMTR 086 | 1605 Research paper

DOI 10.14622/JPMTR-1605

UDC 655.1 = 774.8 (535.37)

Received: 2016-02-27

Accepted: 2016-05-24

A method to compensate fluorescence induced white point differences in proof-processes by printing liquid fluorescent brightening agents using inkjet

Daniel Bohn1, Michael Dattner2, Stefan Fehmer3, Peter Urban1

E-mails: Dbohn@uni-wuppertal.de; Michael.dattner@bst-international.com; S.Fehmer@laudert.de; Purban@uni-wuppertal.de

1 University of Wuppertal, Faculty for Electrical Engineering, Information Technology and Media Technology, 42119 Wuppertal, Germany

2 BST eltromat Int. GmbH, Heidsieker Heide 53, 33739 Bielefeld, Germany

3 Laudert GmbH & Co. KG, Von-Braun-Straße 8, 48691 Vreden, Germany

Abstract

One of the key goals in producing paper and cardboard in the print industry is to achieve a high whiteness degree. This is usually realized by fluorophores called OBAs (Optical Brightening Agents) or FBAs (Fluorescent Brightening Agents). The heavy use of FBAs in production substrates, while proof substrates contain a varying amount of FBAs, results into serious difficulties in any color management process, especially in terms of a white point correction.

In this study, an alternative procedure is presented to achieve an illumination independent colorimetric correlation and a visual match between most proof- and production substrates. This is achieved by printing defined amounts of liquid FBA using inkjet with variable area coverage.

Keywords: OBA, color management, FBA compensation, OBA compensation, carrier

JPMTR 087 | 1511 Case study

DOI 10.14622/JPMTR-1511

UDC 655.1 (774.8)

Received: 2015-12-14

Accepted: 2016-09-09

Does the use of black ink still comprise the “darkest” issue of CMYK printing?

Yuri Kuznetsov and Maria Ermoshina

E-mail: yurivk@mail.ru

St. Petersburg State University of Industrial Technology and Design, North-West Institute of Printing, NWIP, Jumbula Lane 13, Saint Petersburg, 191180, Russia

Abstract

Black ink can be used for multicolor printing to different extent within each of such multiple purposes, as: replacement of the achromatic component of three chromatic inks combination; reproduction of the image achromatic colors; expanding the color gamut; providing print security features… The relationships and effects within these functions are discussed in the paper on the background of prepress facilities evolution starting from the times of photoengraving and analogue scanners of 60’s up to the precise digital color control of today. The results of comparative colorimetric analysis of the sets comprising cyan, magenta and yellow (CMY), and cyan, magenta, yellow and black (CMYK) revealing the black in particular effect of expanding the print gamut by providing the darker chromatic colors which aren’t available for any com- bination of the other three process ones are also presented.

Keywords: color gamut, achromatic component, chromatic color, UCR, GCR, UC

JPMTR 1510 Professional communication

DOI 10.14622/JPMTR-1510

UDC (655.1) 762 | 62-1/9

Received: 2015-12-10

Accepted: 2016-05-16

Evaluation of in-line viscosity measurement sensors in gravure printing

Henrik Knauber, Peter Schöffler, Thomas Sprinzing, Armin Weichmann

E-mails: hk037@hdm-stuttgart.de; ps092@HdM-Stuttgart.de; sprinzing@hdm-stuttgart.de; weichmann@hdm-stuttgart.de

Hochschule der Medien, Institut für Angewandte Forschung (IAF), Nobelstr. 10, 70569 Stuttgart, Germany

Abstract

For the stabilisation of printing quality, gravure printing machines are normally equipped with viscosity measurement systems. Recently two newly developed viscosity measuring systems, a microelectromechanical tuning fork sensor and an acoustic wave sensor, were introduced to the market. Those systems compete with the traditional rotary viscometer and the dropping body measurement. A system comparison of the different systems were implemented and performed at a Rotomec MW 60 rotogravure press. The aim was to find a system for in-line viscosity measuring of printing inks, which is as accurately as possible and does need minimal cleaning effort. Four experiments were conducted to evaluate the different viscosity measuring instruments: accuracy of the solvent concentration measurement, equipment capability, temperature behaviour in ink and influencing factors of viscosity measurement in the printing process. The results show that the acous- tic wave sensor and the rotary viscometer are suitable for the viscosity measurement in gravure printing.

Keywords: viscosity sensors, tuning fork sensor, acoustic wave sensor, rotary viscosimeter