Considerations on bulged-out print shoulders due to mesh depression and high ’emulsion over mesh’ in screen printing
Institut für Innovative Anwendungen der Drucktechnologien (IAD), Hochschule der Medien, Nobelstr. 10, 70569 Stuttgart, Germany
In screen printing sometimes at the edges of an ink deposit that is wider than a few millimetres a phenomenon occurs, which can be described as an elevated edge or better as bulging-out shoulders. This can be a print quality issue if subsequent overprints need to be carried out. The shoulder bulge-out effect typically occurs if the stencil build-up is not well adapted to the targeted type of print pattern (e.g. fine lines vs. large solid tone areas). The effect is described in screen printing textbooks and some scientific articles but not yet tackled theoretically. As an approach, here a simple model, assuming a quasi-infinite line as the pattern to be printed is used. The model combines the elongation of the mesh caused by the mesh tension and the additional stress applied by the squeegee with material properties and calculates the depression of the mesh towards the substrate during the squeegee movement between the two edges of the stencil opening. The developed relationship ends up in an equation that is solved numerically by means of a look-up-table (LUT) approach. Graphs are derived that show the dependencies on print line width, stencil build-up, stresses applied and materials used.
Keywords: print quality, squeegee pressure, mesh elongation, ink deposition
JPMTR 101 | 1711 Original scientific paper
Optimal image encoding for hard copy production and method of its efficiency estimation
Yuri V. Kuznetsov1 and Andrey A. Schadenko2
E.mails: email@example.com; firstname.lastname@example.org
1St. Petersburg State Institute of Cinema and Television, Ul. Pravdy 13, St. Petersburg, 191119, Russian Federation
2St. Petersburg State University of Industrial Technology and Design, Ul. Jumbula 13, St. Petersburg, 191180, Russian Federation
Unlike in a soft copy generating, the multilevel pictorial data are, after capturing by camera or scanner, once again encoded in prepress to get the output signal governing the halftone printing in bi-level, “ink – no ink” fashion. Criteria of such encoding optimization are comprised in the transfer through physical plate making and press communication channel onto a print with as much as possible of original image data perceivable for a viewer. It undermines the pro.viding of mutual conformity for parameters of a source image and channel, as well as for properties of an output print and vision. On the background of the screening developments overview for the last half a century, the paper presents: discussion of tone spatial dispersion in halftoning and accompanying contour and fine detail distortion; such distortion corrections and the method of quantitative estimation of their efficiency; principles of an image optimal encoding in prepress and their implementation in the High Definition Halftone Printing (HDHP); including results of testing and promotion issues of its practical application; and disclosed approach potential with the spatial dispersion adaptive to an arbitrary contour. Samples of test images and fragmentary photographs from illustrative print trails and jobs using HDHP are also presented. On this basis, the paper pretends to disclose some mainstream aspects bypassed in the most of other publications on halftoning.
Keywords: image data encoding, halftone dot, printing, adaptive halftoning, image sharpness, print definition
JPMTR 102 | 1713 Review paper
The possibilities of RFID and NFC tag implementation in dairy segment
University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Snežniška 5, SI-1000 Ljubljana, Slovenia
With the help of printed electronics, the product-consumer relationship can be further evolved and explored, thus enabling the building of a deeper emotional connection. The growing implementation of online connectivity – Internet of things, is one of the important driving factors for the printed electronics market. The goal of our study was to estimate implementation options of printed electronics into the packaging of dairy products according to the type of packaging with considering the approximation of the cost per unit. Knowing that the dairy segment is mainly a commodity, we assume this implementation will have a big influence on the product price. Our research showed that the added value in the commodity segment is too low to be able to cover the cost of implementation of the RFID tag. Printed electronics and, generally speaking, smart packaging has found its place in a segment where a need for security elements or the product is higher priced and the extra cost of a tag does not represent a high burden. There is a great potential in the packaging of pharmaceutical and cosmetic products, where the product’s identity is key. There is also a potential in a food segment where food safety is crucial; these are nutritional products for children, for example, baby milk. The main obstacles of printed electronics and smart labels, in general, are in the high unit price per product because the uses are mostly carried out on luxury goods and those are smaller in quantities. Taking it into consideration the printed electronics providers cannot achieve large quantity productions and therefore lowering of price because the economy of scale is insufficient. Until there are no implantations in the segments where the quantities are high, the RFID tag has lesser chance to get its price lowered.
Keywords: smart packaging, consumer interaction, aseptic packaging, food packaging
JPMTR 103 | 1712 Case study