• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.4
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• pp.77-84
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• 2012

The lithographic process depends on a satisfactory ink-in-water emulsion being formed during printing and the speed of wet presses makes the choice of fountain solution vitally important as the ink and fount must react quickly to form a stable emulsion. Ink and water come into contact with each other on the rolls of the press and are forced together in the roll nips. The water is not soluble in the ink since it is slightly fat. Instead, an emulsion is formed, a heterogeneous mass consisting of small water drops mixed into the ink, if the water feed is too great. This emulsification can affect the properties of an off-set ink and negatively affect the printability. So we investigated the effects of the emulsification of phenol free heat-set ink and existing heat-set ink on printed quality, such as amount of ink transfer, printed density, print-through and uniformity. We used Duke emulsification tester for the emulsification of inks, and used IGT printability tester for printed quality. The printed quality were measured by densitometer and were evaluated by the image analysis system. Compared to conventional printing ink, phenol-free ink showed better results of the printability at the emulsification.

• Journal of the Korean Graphic Arts Communication Society
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• v.19 no.1
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• pp.28-41
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• 2001

Rheological properties of ink and Ink-Water balance are the important factors in lithographic printing. Laboratory test method which determines the emulsification rate of dampening solution and ink has been described. The emulsification theory and laboratory test method deduced from Surland and it has become a useful tool for the industry. The effects of pH value and surface tension of dampening solution on the emulsification rate has been tested by many researcher. In this paper we focused on the factors which influence in the emulsification such as pH and surface tension of dampening solution and emulsifying temperature. To study on the factors determining the emulsion velocity, we have measured water pickup and calculated emulsion velocity constant 'k' and activation energy.

• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.1
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• pp.123-132
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• 2002

The literature often mentions the hardness of water in dampening solutions as possible source of problem. In most literature describes that the water hardness affects print quality. However water hardness affects not only print quality, but also emulsification of ink and dampening solution. Therefore the purpose of this study was to determine if water hardness actually affects the emulsification rate of dampening solution and ink. And this study for the factors determining the emulsion velocity, we have measured water pick-up and calculated emulsion velocity constant 'k' and activation energy.

• Proceedings of the Korean Printing Society Conference
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• 2001.06a
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• pp.135-140
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• 2001

Laboratory test method which determines the emulsification rate of dampening solution and ink has been described In lithography using the mutual repellence of oil and water, the emulsification is produced by dispersion of dampening water and ink because of the printing pressure on a practical press. Rheological properties of Ink-Water balance are the important factors in lithographic printing. The emulsification theory and laboratory test method deduced from Surland and Kim. It is shown that the emulfisication curves relate to the rates of change in the emulsifide ink\`s flow properties, to the shear stability of the emulsion formed To study on the factors determining the emulsion velocity, we have measured water pickup and calculated emulsification velocity constant \`k\` and activation energy.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.327-338
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• 2011

This study was carried in order to manufacture the high quality coated paper. High quality includes not only properties of coated paper but also final print quality. In this study, new acrylic-styrene emulsion was polymerized in laboratory and compared with styrene-butadiene latex. Low-shear viscosity of coating color was decreased with increasing acrylic-emulsion dosage. WRV was increased with addition and decreased with substitution of acrylic-emulsion. Paper gloss, brightness and whiteness were increased and PPS and opacity was slightly decreased with acrylic-emulsion. Ink gloss was increased with using No. 3 acrylic-emulsion due to lower ink setting properties. However No.1, 2 emulsion shows opposite situation. Surface strength of coated paper was increased with using No. 3 acrylic-emulsion These results indicate that high quality coated paper can be manufactured with using No. 3 acrylic-emulsion.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.1
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• pp.37-42
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• 2012

This study was carried in order to manufacture the high quality coated paper. High quality includes not only physical and optical properties of coated paper but also final print quality. In this study, new acrylic-styrene emulsion was polymerized in laboratory and compared with conventional styrene-butadiene latex. Low-shear viscosity of coating color was decreased with increasing acrylic-emulsion dosage. Small amount of acrylic emulsion addition increased water retention, but further addition decreased it. Acrylic-emulsion addition improved paper gloss, brightness and whiteness, but decreased PPS and opacity slightly. Ink gloss was increased with using No. 3 acrylic-emulsion due to lower ink setting properties. However No. 1 and 2 emulsion showed the opposite result. Surface strength of coated paper was increased with using No. 3 acrylic-emulsion. These results indicate that high quality coated paper can be manufactured with using No. 3 acrylic-emulsion.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.3
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• pp.74-83
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• 1998

The phenomenon of decrease in sizing efficiency when the stock temperature is increased is well recognized as summer sizing, and this is believed to be caused by uneven distribution of sizing agents on paper surface most often incurred by coagulation of sizing agents. When unevenly sized paper is used as coating base stock, nonuniform consolidation of the coating layer may result, which, in turn, causes uneven distribution of binder on coating surface. This causes nonuniform ink absorption to produce print mottle. In this study the effects of simple or polymeric electrolytes, storage temperature and time on the coagulation of cationic dispersed rosin size were investigated using a turbidity measurement method which was verified to correlate well with the particle size of rosin emulsion or its coagulates. Handsheets sized with rosin dispersions coagulated under various conditions were prepared and their sizing degree and coated paper properties including gloss and ink density were examined. The relationship between the sizing nonuniformity of coated papers and its ink absorption property was evaluated. Turbidity of rosin emulsion increased as the storage temperature and time were increased. Addition of simple or polymeric electrolytes caused reduction in $zeta$ -potential of the rosin dispersion and accelerated the coagulation tendency substantially. Reversion of the $zeta$ -potential of rosin dispersion, however, did not occur when coagulation was induced with simple electrolytes. On the other hand, addition of an anionic polyelectrolyte reversed the $zeta$ -potential of the flocculated rosin dispersion. This indicated that electrical double layer compaction and bridging flocculation were coagulation mechanisms for simple and polymeric electrolytes, respectively. Sizing degree decreased as coagulation of rosin was increased. Paper gloss, ink gloss and ink density were increased when sizing degree of base stock was increased most probably due to prevention of base paper swelling and increased binder migration to coating surface. This suggested that uneven printing ink density occurred when uneven sizing development was induced by coagulation of rosin particles.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.536-539
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• 2004

A novel ink-jet printing method was investigated for fine patterning of phosphor layer in PDP using a precision nozzle printing. A reverse emulsion method was developed for the synthesis of nano-sized phosphor powder that could be formulated in the phosphor ink. The composition of the phosphor ink including charge controlling agents, solvent, dispersant and nano-sized phosphor powder was optimized for the fine patterning of phosphor layer for high resolution PDP.

• Journal of the Korean Graphic Arts Communication Society
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• v.26 no.2
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• pp.1-13
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• 2008

Printed mottle of coated paper is one of the most common phenomenon and the most difficult problem in offset printing. Offset printing is processed mainly processed by the attractive properties between water and oil, so all inks for off-printing must work with dampening solution(water). It may cause the emulsion on the printing nip from the printing pressure. This study aimed to investigate the effect of emulsified inks on print mottle from emulsified cyan ink by force with each different IP A contents. We measured the print mottle by densitometer and image analysis method. The emulsified inks also give effect to now properties of inks and it caused more ink transfer rate, however, it caused low density of inks. Moreover the emulsified inks were spreaded to around of dots and cause the thinning density on the non-printing area like print mottle. The results showed that the emulsified inks also cause scumming on the printing result with little mistake of adjusting dampening solution and mostly decreasing dot reproduction. So we could find out the obvious effect of emulsified inks to print mottle.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.2 s.120
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• pp.31-37
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• 2007

Lithography like off-set printing is processed using the repellent properties between water and oil, so all inks for off-printing must work with dampening solution(water). The dampening water may cause the emulsification of ink by the printing pressure in the printing nip. This study aimed to investigate the effect of emulsified inks on print mottle. The cyan ink was emulsified artificially with the different IPA(isopropyl alcohol) content in this study. We evaluated the print mottle by densitometer and image analysis method. The print mottle phenomenon was directly affected by IPA content. The emulsification of inks also had an influence on flow properties of inks and it increased ink transfer rate. It, however, caused low ink density. Moreover the emulsified inks were spreaded to around dots and cause the thinning density on the non-printing area like print mottle. The trial printing showed that the emulsified inks also cause scumming on the printing result with little mistake of adjusting dampening solution and mostly decreasing dot reproduction. We could, therefore, find out the obvious effect of emulsified inks on print mottle.