June–July 2017

Gorazd Golob

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Modifying the qualitative properties of print by surface treatment of flexographic printing plate

Tamara Tomašegović¹, David Beynon², Tim Claypole² and Sanja Mahović Poljaček¹E-mails: ttomaseg@grf.hr; d.g.beynon@swansea.ac.uk; t.c.claypole@swansea.ac.uk; smahovic@grf.hr
¹ University of Zagreb, Faculty of Graphic Arts, Getaldićeva 2, 10 000 Zagreb, Croatia
² Welsh Centre for Printing and Coating, College of Engineering, Swansea University, Swansea University Bay Campus, Engineering East, Crymlyn Burrows, Swansea, SA1 8EB, UK

Abstract

In the fast-pace technology development in graphic industry, modern flexography has found its domain mostly in the packaging sector and it is increasingly of interest for functional printing. Functional printing has a relatively low market value but greater interest in research. Due to the new qualitative requirements, workflows and materials used in flexography had to be updated and improved. The application of digitally controlled processes and procedures has taken the place of the analogue production, together with the new methods of material processing and improvements of the materials themselves. This research focuses on the functional modification of photopolymer flexographic printing plate’s properties with the aim of achieving optimal output quality. During the transfer of the printing ink from the anilox to the printing plate and then to the printing substrate, surface properties of the printing plate influence the quality of the print. Therefore, surface properties of the printing plate should be compatible with the used printing ink and the printing substrate, which is especially important when using new formulations of inks and experimenting with different printing substrates and applications, for example in functional printing. In this research, samples of photopolymer flexographic printing plates were exposed to UV-ozone treatment in order to modify the surface properties of the photopolymer material. Results have displayed significant changes in surface free energy of the photopolymer material when the printing plate samples were exposed to the UV-ozone for periods up to 5 minutes. In order to analyze the quality of the prints produced with UV-ozoned flexographic printing plates, test prints were produced. Prints produced with printing plates with longer UV-ozone treatment have displayed the qualitative changes in the reproduction of fine printed elements, i.e. the width of fine lines, coverage values, ink volume on print and the definition of the shape and edges of printed elements. Changes of named properties of the print are significant for conventional, and in many cases for functional printing. Performed research proved that the functional modification of flexographic printing plates with the aim of improving the print quality is possible. The UV-ozone treatment is a procedure where the printing plate is exposed to significantly higher energy than with conventional UVA and UVC tubes. Therefore, the duration of the UV-ozone treatment must be precisely adjusted in order to maximize the quality of the print, while at the same time maintaining printing plate’s functionality.

Keywords: flexography, photopolymer, UV-ozone, surface free energy, ink transfer

JPMTR 095 | 1704 Research paper
DOI 10.14622/JPMTR-1704
UDC 777.2-021.465-023.7

Received: 2017-05-09
Accepted: 2017-07-31

Colour management of tablet devices

Reem El Asaleh and Daniel Langsford
E-mails: reem.elasaleh@ryerson.ca; daniel.langsford@ryerson.ca
Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3

Abstract

As of now, the creation and use of tablet devices in society have been strictly focused on the benefits for commercial use. While other devices such as monitors or cameras are capable of device-specific colour management, tablet devices have been left behind with only manufactured colour adjustments available. This has resulted in a limited use of tablet devices such as the Windows Surface, Apple’s iPads and Samsung’s Galaxy Tab S, in the professional/printing industry. In particular, the use of these tablets have had limited integration with an already existing and functioning colour management workflow. This study analyzed and identified the colour reproduction capabilities of specific tablet devices so that possible workflow or industry integrations can be established. The study evaluated each device through the creation of an ICC profile using i1Profiler. The profiles were then compared using Macbeth ColorChecker Classic Chart for key colour comparison and IT8.7/4 for colour difference values (∆E₀₀). Amongst all profiles, general colour gamut was observed using ColorThink Pro software. The outcome of the tests has shown that each device tested thoroughly resulted in an acceptable industry set CIEDE2000 standards with average values below 3. It was also seen that each device is limited by various roadblocks or concerns when looking for future integration into professional industry workflows. Overall, while technically usable, the use of tablet devices in the professional/printing industry depends on the extent to which this industry accepts to integrate these devices in their workflows.

Keywords: colour reproduction, colour differences, colour management workflow, colour gamut

JPMTR 096 | 1705 Case study
DOI 10.14622/JPMTR-1705
UDC 004.92 | 535.2

Received: 2017-05-16
Accepted: 2017-06-29

Technologies for using Big Data in the paper and printing industry

Igor Karlovits
E-mail: igor.karlovits@icp-lj.si
Pulp and Paper Institute, Ljubljana, Slovenia

Abstract

The paper gives a review about the possibilities of using Big Data technologies in the print industry. Current situation and research are presented with a brief overview and description of the data mining process. Process parameters readouts and process modelling by using problem-solving methods open up new possibilities for production efficiency. Different authors have provided solutions for print and print quality related problems by data collection through sensor readouts and real-time monitoring of different production system variables. Major production techniques (offset and flexo printing) have been partly investigated and monitored through closed inline controls, or metadata communication with the use of Job Definition Format. The researchers have found possibilities in solving particular print or production related issues with the use of Big Data techniques or its subsets, but still, no integrated market ready solution exists. A theoretical framework for a corrugated production factory is shortly presented, outlining possible applications and connections for a fully integrated data mining system that could bring the Industry 4.0 in the printing sector.

Keywords: data mining, process control, printing, papermaking

JPMTR 097 | 1706 Review paper
DOI 10.14622/JPMTR-1706
UDC 04.6-022.56(676+655.1)

Received: 2017-07-10
Accepted: 2017-07-30