• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.4 s.117
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• pp.41-46
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• 2006

Printed mottle of coated paper is one of the most common but the most difficult problem in offset printing. Printed mottle is caused by an uneven penetration of Ink into the paper, binder migration, etc. For a high quality printing, development of new paper coating technologies to prevent print mottle is required. So for, the study of solving printed mottle is coated paper absorption controlled by base paper sizing and coating layer binder migration control. As a results, printed mottle has improved in coated paper. But printing is worked by interaction of printing ink, coated paper and printing pressure, then we need to understand of interaction printing work and coated paper. This research focused on a way of improving printed mottle by investigating various printing conditions such as ink dispersion, nip condition and amount of ink transfer using IGT printability tester.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.4 s.117
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• pp.47-52
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• 2006

This study is about the effect from properties of coated paper and ink dispersion to the printed mottle. Ink receptivity would be expected that it is mainly effected by roughness of coated paper Because the transfer of ink can not be uniform with rough surface, it will cause the optical appearance such like printed mottle. And also it may be able to cause the printed mottle from uneven transfer of ink due to absorption property of based paper, depend on size degree, by using dampening in Off-set printing. Each different specific of surface and ink dispersion could cause printed mottle. Therefore this study was carried out by using densitometer and image analysis to show the interaction between properties of domestic coated paper and ink dispersion.

• Journal of the Korean Graphic Arts Communication Society
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• v.22 no.2
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• pp.139-150
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• 2004

Development of the paper coating technologies to prevent print mottle is needed to obtain high quality printing. Printing mottle is recognized as the most common printing problems in using coated paper and which is one of the most difficult problems to solve in offset printing. Print mottle is one of the most important quality properties of printed products and manufacturers strive to improve the paper surface to gain higher and more even print mottle. The prevention of printed mottle requires of coating color formation, especially the minimum of binder migration. The results the uniformity of liquid absorption by paper at very short contact time between paper and testing printing liquids.

• Journal of the Korean Graphic Arts Communication Society
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• v.25 no.2
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• pp.85-93
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• 2007

The printed mottle is recognized as the most common printing problems in using coated paper and one of the most difficult problems to solve in offset printing. Printed mottle is caused by an uneven penetration of ink into the paper and binder migration. The prevention of printed mottle requires of coating color formation, especially the minimum of binder migration. Printing worked by interaction of printing ink, coated paper and printing pressure. In this study, we investigated the effect of the properties changing of coated paper and printing conditions such as ink dispersion, nip condition and amount of ink transfer.

• 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.

• 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.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.04a
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• pp.152-157
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• 2006

Printing mottle of coated paper is one of the most common and the most difficult problems in offset printing. For a high quality printing, development of new paper coating technologies to prevent print mottle is required. This research focused on improvement of printing mottle. Effects of base paper properties, coating color composition and printing conditions such as printing pressure and printing speed on printing mottle were investigated with RI tester and IGT tester.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.495-497
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• 2006

Talc Printing mottle of coated paper is one of the most common and the most difficult problems in offset printing. For a high quality printing, development of new paper coating technologies to prevent print mottle is required. This research focused on improvement of printing mottle. Effects of ink dispersion and printing conditions such as nip conditions, printing pressure and printing speed on printing mottle were investigated with RI tester and IGT tester.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.1 s.119
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• pp.25-29
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• 2007

Print mottle is the spotty and cloudy appearance of the ink on the substrate. Print mottle is influenced significantly by the characteristics of the paper with regard to homogeneity of its structure and its coating. The print mottle can be counteracted, in particular by altering the absorption characteristics of the inks, by changing sequence in which the inks are printed, or by using a advanced coated paper. In this study, we investigated the effect of ink dispersion to the print mottle through trial printing test and also analyzed the correlation between properties of coated paper and subjective results by statistic method. The result of this study is expected to be applied the basic data to solve the problem of printing mottle.

• Journal of the Korean Graphic Arts Communication Society
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• v.28 no.2
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• pp.31-44
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• 2010

Ever since the introduction of offset lithography, an operator have looked for ways to improve the process by reducing need for dampening solution. Lithography like off-set printing is processed using the repellent properties between water and oil, so all inks for lithography printing must work with dampening solution. The dampening solution may cause the emulsification of ink by the printing pressure in the printing nip. Emulsified ink changed viscosity, tack and causes problems such as bad transfer, uniform density and printed mottle. For a high quality web printing, we studied the effect of emulsified heat-set web inks on the printability, such as amount of ink transfer, printed density and uniformity. For this study, we were carried out by using IGT printability tester C1. For determination of ink properties using the spread meter and Thwing Albert Ink-o-meter, and using the densitometer and image analysis for printed quality determination. The experimental results of this study, we look forward to can be used as the basis for improve of the web print quality.