• Journal of the Korean Graphic Arts Communication Society
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• v.25 no.1
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• pp.109-120
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• 2007

In gravure printing, the amount of ink fill into the cells has a great effect on the qualities of final printed products. And printability of final products is determined by every kinds of variables. Ink transfer process is not verified scientifically because gravure cell is small and printing speed is rapid. In order to understand the ink transfer mechanism of conventional gravure, this study is performed using the Computational Fluid Dynamics Evaluation. Flow-3D simulation software is used for considering of Newtonian flow. Among the various factors, this study have dealt with gravure cell types used computer simulation in order to define distinctive features in ink flow in the cell. The results of simulation, it defined the distribution of pressure, speed, stream function, viscosity, shear rate, surface tension during the gravure printing. It is founded out the difficulties and characteristics according to the printing speed and viscosity of Gravure ink.

• Journal of the Korean Graphic Arts Communication Society
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• v.26 no.1
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• pp.87-96
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• 2008

Paper stock could be situated in a cooled environment seasonally and/or regionally otherwise it is stored in a controlled warehouse. In this paper, printing problems on a cooled paper are investigated and characterized in terms of paper properties. For this purpose, various kinds of sample are cooled down under a specially designed freezing device and printed for observing their printability. Causes for poor ink transfer on a cooled paper are suggested due to condensation, surface inactivity, and rheological change in ink film. Paperboards with higher amount of binder, thick and/or multi-coated layers are more vulnerable to poor ink trap. Severe drying of wet coating could cause a similar result as that of the coatings with higher binder formulation. It is shown that more absorptive porous structure is desirable for better ink receptivity in a cooled status. Printing on a dampened surface may be an indicator for ink transferability on a cooled paper. Finally, desirable directions for papermaker and printshop are suggested.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.11a
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• pp.17-27
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• 2006

Paper could be situated in a cooled environment seasonally or regionally otherwise it is forced to be in a controlled circumstance. In this paper, printing problems on a cooled paper are investigated and characterized in terms of paper properties. For this purposes, various kinds of sample are cooled down under a specially designed freezing device and printed for observing their printability. Causes for poor ink transfer on a cooled paper are suggested due to condensation, surface inactivity, and rheological change in ink film. Paperboards with higher amount of binder, thick and/or multi coat layers are more vulnerable to poor ink trap. Severe drying could cause the same effect as that of higher binder formulation. It is shown that more absorptive porous structure is desirable for better ink receptivity in a cooled status. Printing on a dampened surface may be an indicator for ink transferability on a cooled paper. Finally, desirable directions for papermaker and printshop are suggested.

• Journal of the Korean Graphic Arts Communication Society
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• v.28 no.2
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• pp.45-56
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• 2010

The computer simulation is presented of gravure ink transferring behavior and penetration to the paper when an gravure roller is used to transfer a printing ink onto a substrate. The three dimensional unsteady ink motion is simulated by Polyflow package software and experimented by IGT gravure printing test machine. The simulation is performed where the flow domain is bounded above by a stress free surface and bounded below by a moving substrate. Specific predictions are made for particular pattern of cells and substrates. Cell size and ink rheological properties are found to be the principal determination of transferring behavior. Simulation is currently restricted to the flow domain beneath the receding meniscus. Both Newtonian and shear thinning inks are considered.

• Journal of the Korean Graphic Arts Communication Society
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• v.25 no.1
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• pp.1-9
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• 2007

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.910-913
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• 2009

This paper examines attaching speed, detaching speed and contact time which affected in the ink transfer ratio and presents the best conditions for fabrication process of electrodes with Ag-ink using microcontact printing method. In conclusion, it shows the best printing characteristic by two conditions. One of condition is the attaching speed have to within less than 1mm/s and the detaching speed is high velocity as 1000mm/s and the contact time is taken about the minimum time when inking process. Another condition is the attaching speed have to within more than 100mm/s and the detaching speed have to within less than 1mm/s and the contact time is longer than 30second when the printing process. As using these condition and the stamp sized 5cm${\times}$5cm, it was possible for printing equally until $30{\mu}m$ of width. The printed thickness of a electrode was about 300 to 500 nm, the surface roughness was about dozens nm under 50 nm.

• Tribology and Lubricants
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• v.30 no.4
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• pp.224-233
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• 2014

We prepared polyester-polyamines to improve the effect of carbon black dispersibility for use in thermal transfer ink, and synthesized polymeric dispersing agents by two-step reactions. In the first step, we made polyester by polycondensing 1,6-hexanediol and adipic acid. The resulting polymers had carboxylic acid, which was linked with polyamine via an acid-base reaction. We then characterized the polyester-polyamine structure by NMR spectroscopy and Fourier transform infrared spectroscopy (FT-IR). We also determined the basic characterizations such as total acid numbers (TAN) (5.0-67.5 mgKOH/g), hydroxyl values (27.1-67.5 mgKOH/g), and molar masses ($M_n=1.6-8.4kg\;mol^{-1}$) for the polyester and total base numbers (TBN) (15.3-57.1 mgKOH/g), hydroxyl values (33.0-79.8 mgKOH/g), and nitrogen contents (1.02-3.48%) for the polyester-polyamine polymers. We thus prepared thermal transfer ink using carbon blacks and the polyester-polyamine dispersing agents, and evaluated the resulting mixtures for printability, adhesive force, storage stability, ink appearance, ink gloss, and processability. These mixtures showed significant dispersibility for carbon black in the ink. Thus, we concluded that the dispersibility of the polymeric materials depended on the polyamine structure and the hydrophilicity-hydrophobicity distribution of the polymeric dispersants.

• Journal of the Korean Graphic Arts Communication Society
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• v.27 no.1
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• pp.59-71
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• 2009

Measuring ink penetration is one of the best ways to know paper printability. Ink penetration was effected by physical properties of newsprint paper. This study was carried out for the purpose of improvement printability with ink penetration of domestic newsprint paper. The samples were prepared by means of 20 newsprint paper manufacture company in Korea, and were tested by IGT printability tester. The results of this experiments showed that the depth of ink penetration according to the printing pressure. The maximum points in ink transfer curve and the coefficients of oil absorption of the papers also depend mainly upon the situation of anchor points.

• Journal of the Korean Graphic Arts Communication Society
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• v.10 no.1
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• pp.81-90
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• 1992

The charater of standing box printing reguires a rich representation in a light and a shade of color and caues the modern photographs to be abundant of the ink and also shows the continuity of which any other printing is incapable because of its profound gradation. The clear printing in gravure can be said to be due to the good transfer of the ink - the completion of the transference of the ink into the stencil paper and the clear transference of the printing tone. The most inportant matter is the distance between the printing press and the doctor line. It is the matter of the structure and arrangement because of giving the most affect on the dryness of the ink in the cell. The glue of the ink in gravure changes by the kinds of the dye and the cellusolve used. To make the printing somoothly progressive from the high glue of the ink to the low glue of the ink will have to be used, which will be possible to choose the ester.ose the ester.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.3
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• pp.1-10
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• 2014

Offset paper printing is a promising roll-to-roll technique for color printed materials. Although it is no doubt that understanding ink transfer mechanism in offset printing process is necessary to achieve high printing quality, investing the relationship between inks and substrates at the nip is difficult experimentally due to high printing speed. In this paper, rheological behavior and splitting point of the ink at the nip is studied using package software Ployflow and Flow 3D based on Navier-Stokes equation. Polydimethylsiloxane (PDMS) ink and IGT printability tester were used for an model ink and experiment to compare with that of simulation data, respectively. As a result, higher viscosity at state flow and pressure increased ink transfer due to higher possibility of presence of cavitation at the nip and increase in covering area ratio. These results have shown good agreements with experimental data compared by measuring density of print through.