• Journal of the Korean Graphic Arts Communication Society
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• v.16 no.2
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• pp.45-59
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• 1998

Halftonig is a technique to create the appearance of intermideate tone levels by controlling the spatial distribution of the binary pixel values. Recently, many printing devices such as image setter, inkjet printer, laser printer and facsimile, generate image, they require the technique. Ordered dither is achieved comparing the gray scale image to periodic array. This method is fast, but it occurs periodic patterns. Conentional error diffusion generates a good image. But processing speed is very slow and appeares worm artifacts in middle tone scale. To improve it, Bns(Blue noise Screen) is developed based on Gaussian distribution. In this paper, we discribe methods to design BNS based human visual characteristics and to improve blue appearing at edge area of image by USM(using unsharp mask).

• Journal of the Korean Graphic Arts Communication Society
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• v.15 no.2
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• pp.57-76
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• 1997

A color halftoning is the process of generating halftone images for the different color plans, for example, cyan, magenta, yellow, and black for a offset printing device. A conventional halftone technique, so called AM screening, is simple and easy to implement, but the halftoned dot patterns by using this method is not free for the moire` fringe. Moire` patterns are caused the power spectrum distribution on low spatial frequency domain. To avoid Moire` patterns, the conventional screen require the different screen angles for each color plans. Recently, Ultra-fine and 7 color printing methods are developed to expend the color gamut. In 7 color printing method must be used the halftone technique of random and blue noise characteristic to avoid Moire` fringe.

• 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.43 no.1
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• pp.17-22
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• 2011

The conventional coated paper has many functional problems for printed RFID tag. This study was carried out in order to evaluate the effect of coating color components on conductivity of printed coated paper. It has been well known that the efficiency of printed RFID tag is influenced by surface properties of substrate. The required properties for suitable substrate of printed RFID tag are high smoothness and waterproof property. In this study high grammage base paper surface sized with PVA was used. Coated paper was manufactured with five different formulations. Types of coating pigments and dosage of latex were varied. It was obtained high smoothness and also less binder demand with clay than GCC. On the other hand, suitable surface resistance and smoothness of coated paper for RFID tag was obtained with 20% of latex. Besides it shows the possibility of using coated paper for printed RFID tag.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04a
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• pp.1-6
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• 1999

A study was made to determine the effect of plastic pigment on the coating structure and printability of coated paper. Three basic plastic pigments were investigated such as solid-bead type of plastic pigment, binder type of plastic pigment and hollow type of plastic pigment. In the systems investigated, it was observed that particle shape and structure of plastic pigment had influenced on the rheology of coating color, the state of packing, and the properties of coated paper. The materials investigated were restricted to plastic pigments commonly uesd in paper coating formualtion. Inorganic pigments used in this research were kaolin clay which is platelets and calcium carbonate which is rhombic. Three kinds of plastic pigments were blended in the color made up with two inorganic pigments, respectively. The combination of pigments were carried out (1) to determined the effect of paticle structure of plastic pigment on the state of dispersion of coating color, (2) to observe the effect of temperature of calender on the property of coated paper prepared with plastic pigment. The data indicated that binder and hollow type of plastic pigment had the best results on improving the properties of coated paper such as paper gloss, opacity and air permeability ect. and solid-bead type of plastic pigment in the next place.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.251-263
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• 2011

This study was carried out in order to investigate the effect of pre-coating layer on top-coating layer. The coated paper with five different formulations were prepared. The properties of coated paper were measured and correlation between pre and top-coated layer was evaluated. Paper gloss was increased with addition of clay and GCC that has smaller particle size. Roughness was decreased with using smaller particle GCC, clay and talc. The highest thickness was obtained with talc. Brightness and whiteness of pre-coated layer were affected to top-coated layer. GCC 60 shows the highest and ununiform water adsorption during 1sec. The adsorption was higher with increasing coated weight. Talc shows the excellent water adsorption properties due to its wettability. These results indicate that final printability and properties of top coating layer can be controlled with adjusting pre-coating layer.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.3
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• pp.30-34
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• 2011

This study was carried out in order to evaluate the effect of coated weight and calender pressure on conductivity of printed RFID tags. The printed RFID tags have been manufactured with gravure printing and it has been well known that the efficiency of printed RFID tags is influenced by surface properties of substrate. In this study, coated paper was prepared with four different coated weight and three different calender pressure. After printing conductivity ink on coated paper, surface resistance was measured to evaluate the efficiency of the printed RFID tag. It was found that, with increasing of coated weight and calender pressure, the paper gloss, smoothness, brightness and gravure printability were improved while the surface resistance of the printed RFID tag was decreased.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.1
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• pp.26-34
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• 2010

Effects of drying condition (IR radiation) on the optical properties and the printability of coated paper were elucidated at various latex sizes and low and high coating color concentrations. It was found that the smaller latex provided better rheology and higher dry and wet pick strength than the larger one. The high solids coating resulted in higher paper gloss and smaller roughness than the low solids coating, even though the clay addition was reduced by 20 parts in the high solids coating. Increasing IR radiation prohibited binder migration into the base paper. Thus it improved binder distribution and decreased pores in the coated layer, resulting in the increased dry and wet pick strength and the improved printing gloss. On the other hand, the color trapping and ink set-off was impaired with increasing IR radiation. Print mottle index passed through a maximum with increasing IR radiation.

• 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.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.3
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• pp.70-78
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• 2012

For evaluating the printing suitability of electronic copying papers in the aspect of climate conditions, 12 samples of copying papers being generally used in Korea and worldwide were collected. The copying papers were controlled by various temperature and humidity options in conditioning equipment in order to simulate the specific circumstances of dry, temperate or tropical climate, and the pre-heating system of photocopying machines during printing. As results, some copying papers showed several physical problems, especially in recycled copying papers and a normal paper with original printing faulty. These problems of copying papers were mostly resulted in extremely high moisture circumstance, and in lower levels of tensile strength and tensile stiffness. The moisture contents of copying papers during passing through the pre-heater system of photocopying machine could be rapidly decreased because paper is exposed to high temperature around the pre-heating zone. The copying paper, for example of XR3 sample, containing low moisture contents below 2% had high exfoliating possibility of toner transfer from copying paper.