September 2019

A letter from the Editor
Gorazd Golob

Editor-in-chief

The final editing and production of the September issue of the Journal were done during and immediately after the International Research Conference of iarigai in Stuttgart. We are still under the impression of many interesting and quality presentations, and now we are expecting new papers for publication in the Journal.

In the present issue, the original scientific paper on the nonlinearity of screen printed electroluminescent panels stands out among the three articles. By measuring the properties of electroluminescent panels under different conditions, especially at low and high voltages, and in dark and light environment, the authors explain their operation and also open up new possibilities in the study of optical and radiation sensors. The second paper deals with the more traditional area of maintenance strategy of a printing press, where we can improve the knowledge and risk management of the installed equipment in the print house, by the implementation of an appropriate approach. In the third article, the authors present a study of the effect of starch addition in the paper coating formulation on the pitting, which has a significant effect on the surface of coated paper and thus on the quality of the print.

The editor Markéta Držková (marketa.drzkova@jpmtr.org) in the Topicalities of this issue prepared an overview of the new and updated ISO standards, and short info on the results of the survey on system integration – one of the expected topics at Drupa 2020.

Among the new books, she reviewed new publications, among which there is highlighted book on multisensory packaging, and introduction of new and partly refurbished work – a series of 26 books in the field of digital and print media design. Although it is in German, some of the contents of the same authors have already been published in English in the past, so we can hope that this set of textbooks and workbooks will also be available in English in the future and thus used in the wider international area.

The three doctoral theses selected differ in content as well as geographically, thus providing insight into the breadth of the research area we identify with.

Robert Wiesenberger successfully defended his thesis at Columbia University, New York, USA. He researched and presented the life and work of Muriel Ruth Cooper, who worked as a graphic designer, educator and researcher at MIT, as well as her grandness and impact on major turning points in the press and media design in the twentieth century.

Mima Kurian defended her doctoral thesis on 3D printed bone-like composites at Victoria University of Wellington, New Zealand. Using the appropriate material based on chitosan and calcium carbonate, she produced 3D structures with a nano and macro-pores using synthetic biomineralization method, resulting in material comparable to the bone and tested its properties.

At Karlstad University, Sweden, Sofia Thorman defended her doctoral thesis in the field of absorption and distribution of ink in flexography. She investigated the interactions of printing ink with the base substrate as well as with the previously printed surface in flexography and related causes of print non-uniformity. She has also tested the new staining method in other fields and has proven its usefulness for determining water-moisture interference in lithographic offset printing.

Announced changes to the Journals editorial team are already underway, though they have not yet been finally adopted and implemented. You are invited to take the opportunity to publish the results of your research work in the Journal. The call for papers is constantly open. We would also appreciate your tips on interesting events, new books or theses from the fields covered by the Journal, aimed at iarigai members, subscribers to the Journal and all other experts reading and using it as a reference in their research activities.

Ljubljana, September 2019

Nonlinear behavior in electrical properties of fully screen printed electroluminescent panels

Katrin Hirmer1, Christina Bodenstein2, Hans Martin Sauer2, Edgar Dörsam2 and Klaus Hofmann1
E-mails: katrin.hirmer@ies.tu-darmstadt.de; bodenstein@idd.tu-darmstadt.de; sauer@idd.tu-darmstadt.de; doersam@idd.tu-darmstadt.de; klaus.hofmann@ies.tu-darmstadt.de
1 Technische Universität Darmstadt, Integrated Electronic Systems Lab, Merckstraße 25, 64283 Darmstadt, Germany
2 Technische Universität Darmstadt, Institute of Printing Science and Technology, Magdalenenstr. 2, 64289 Darmstadt, Germany

Abstract

We study the influences of printing parameters of fully screen printed electroluminescent panels on frequency and voltage dependent electrical properties of these devices. Significant nonlinear electrical features as well as a sensitivity to external illumination were observed. By varying the number of subsequent wet-in-wet printing steps within the dielectric and the luminescent layers of the electroluminescent panel, we studied the capacitive and dissipative behavior of current transport in the device. We used a novel method of high voltage impedance spectroscopy at frequencies between 10 Hz and 1 MHz with voltages up to 70 Vrms and compared measurements taken in dark and illuminated ambiences. We propose a qualitative model on the nonlinearity based on ferroelectric and semiconductive features of the dielectric layers as described by the Drude model.

Keywords: printed electronics, printing parameters, high voltage impedance spectroscopy, 
AC powder electroluminescence, electroluminescent panel characterization

JPMTR 125 | 1905 Original scientific paper
DOI 10.14622/JPMTR-1905
UDC 655.1:537.5/530.1

Received: 2019-03-07
Accepted: 2019-09-15

An approach to risk-based maintenance strategy of a printing press

Avijit Kar and Arun Kiran Pal
E-mails: karavijit29jet@gmail.com; arunkiranpal@gmail.com
Department of Printing Engineering, Jadavpur University, Salt Lake Campus, Block-LB, Plot-8, Sector-III, Salt Lake, Kolkata-700098, India

Abstract

The unexpected failures, downtime associated with breakdown and make ready, loss of production and higher maintenance costs are the major problem in any printing press. Risk based maintenance strategy helps in designing an alternative methodology to minimise the risk by identifying the breakdown pattern and then increasing the reliability. Reliability analysis is necessary for every type of machinery for fault detection, risk assessment and evaluation, and maintenance planning. The probability of failures that hinder the reliability can be influenced by some technical, administrative or management actions. The aim of the proposed study is to analyse reliability and availability for maintenance planning on the basis of risk index and overall equipment effectiveness. And maintenance of equipment is prioritized based on the risk which helps in reducing the overall risk of the press.

Keywords: reliability, availability, risk index, overall equipment effectiveness

JPMTR 126 | 1907 Research paper
DOI 10.14622/JPMTR-1907
UDC 655.1|62.7:005.2

Received: 2019-07-10
Accepted: 2019-09-05

The starch addition to a curtain coating formulation and its effect on pitting

Samantha L. Schoenfelder, Alexandra Pekarovicova and Paul D. Fleming
E-mail: a.pekarovicova@wmich.edu
Center for Printing and Coating Research, Western Michigan University, 4601 Campus Drive, A-217 Floyd Hall, Kalamazoo, MI 49008

Abstract

An undisclosed recycled fiber board mill installed a “two-slotted” curtain coater to replace an air knife coater, which enabled a high-quality coating without past speed limitations. With the curtain coater’s installation, however, a prominent defect arose, known as “pitting”. Pitting occurs when the coating of the sheet has small holes that mar its surface, which, when clustered together or larger in size, can cause print break-up. Starch was added to the formulation to modify rheological properties of top and bottom curtain coatings, and advance water retention capabilities of them. Results show the original formulations with no starch were more thixotropic than the starch formulations. Starch aided in reducing the low shear viscosity by as much as 25 %, which had a large impact on converting the system from a strongly elastic rheology to a more viscous one. Such a move toward a more purely viscous system helped to prevent the elastic stretching and reduced bubble formation in the coatings. Starch addition also increased water retention capabilities of the coatings. The pitting significantly decreased during these trials, with lower overall pit counts and area pitted.

Keywords: coating color, coated paperboard, air entrapment, rheology, surface free energy

JPMTR 127 | 1820 Research paper
DOI 10.14622/JPMTR-1820
UDC 676.2:547.4/667.6

Received: 2018-12-06
Accepted: 2019-09-05