• 펄프종이기술
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• 제39권4호
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• pp.29-37
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• 2007

The effects of latex particle size, basis weight of base paper and coating color concentration on the printing quality of coated paper were investigated. Coating colors were prepared with five types of latexes having different particle sizes. Coated papers were produced with high solid coating colors and with low solid coating colors in a industrial coater, respectively. In high solid coating colors, rheology modifier was used and GCC content was high. It was concluded that, in order to control binder migration and hence print mottle, latex particle sizes shall be controlled as well as formation, sizing degree and roughness of basis paper.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 추계학술발표논문집
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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.

• 한국인쇄학회지
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• 제23권2호
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• pp.143-159
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• 2005

The printing could not expect the print effect of the specific character of a printing material. Specially, a property of the paper that we are aware of the substrate has controled printability as well as run ability. The objective of this study was to measure substrate properties by measuring the water receptivity in order to know the degree of the uniformity on surface of paper. Therefore, the water receptivity was measured by fluid bridge method. And then the physical properties of samples such as ink set-off, porosity and print mottle of domestic coated papers were measured by Tappi method. Accordingly, this study obtained the outcome of water receptivity. And then we could know that the relations between water receptivity and physical properties of the paper samples have correlations. There are many measurement equipments to find out print mottle by the measurement of the reflected density at this point in time. However, it is thought that the fluid bridge method is the most proper way to find out print mottle, though there are many other ways to figure out.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2000년도 춘계학술발표논문집
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• pp.118-125
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• 2000

Gloss uniformity on unprinted coated papers is oftenly called as 'Surface Feeling' in market and roles as a very important criteria when a customer choose a paper. However, there is few researches on this quality so far and even there isn't much knowledge on the characteristics of gloss variation, ie what it is, where it comes from etc. Therefore, there should be a pre-research on its characteristics, factors, measuring method or tools prior to the following development activities. In this paper, we obtained about a dozen of papers including foreign products and measured not only basic properties of them, but also various characteristics related to ununiformity. Our experiments went further to printing, but that area is excluded in this paper. Also, we investigated several instruments for measuring gloss variation by an objective way all over the world and tested with our own samples so that we tried to find out which one is best-correlated with visual appreciation and suggest its results as possible. We found out several things from these experiments including what is difference between good and bad gloss uniformity, the factors of gloss variation, and the results of measurement for gloss variation with instruments.

• 펄프종이기술
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• 제47권2호
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• pp.9-16
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• 2015

High loading of base paper is regarded as one of reasons to aggravate fold cracking of coated paper. But the relationship between the ash content of base paper and fold cracking of coated paper has not been shown yet. We investigated the effect of ash content in base paper on the fold cracking of coated paper. Handsheets with three different ash contents (19.5-23.5%) were prepared, and double layered coating were applied on the top side of the handsheets. A gravimetric water retention meter (AA-GWR) was employed to fold the paper with a uniform pressure after solid printing on the coated surface. The fold cracking was digitized by calculating the cracked area by means of an image analysis technique. Results suggested that high ash content in the base paper increased the fold cracking of the outer surface of coated papers. In the case of inner surface greater fold crack areas were obtained, and the number of cracks decreased because long and wide cracks were formed. Reduction in tensile strength and thickness appeared to give greater fold cracking for highly loaded papers.

• 한국인쇄학회지
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• 제29권1호
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• pp.1-21
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• 2011

Because of high demand of color quality of the prints, proof prints are more important for end-user to predict and correct the final prints directly as an intermediate. Thus, proof prints can be used as a reference to take minimum ${\Delta}E^*ab$between the originals and finals in the field. The advantage of proof prints is to predict and correct color easily through the RIP(Raster Image Processor) without printing plates and plate making steps. While, it is thought that the proof systems are almost equivalent to the press in the past, present proof systems are more simple to take proof prints more easily due to the automation and digitalization. This paper addresses a method to perform an accurate profiling according to proof paper types and find optimal proof papers which meet proofing requirement. Although proof papers are matched with ISO 12647-7, we were trying to reduce ${\Delta}E^*ab$, In addition to the above, through the Gamut Mapping and Iteration, We were trying to find optimal proofing conditions.

• 펄프종이기술
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• 제41권3호
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• pp.1-7
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• 2009

Talc as a coating pigment has been developed in order to replace GCC and clay for matte grade and has received much attention due to various advantages including good gravure printability. In order to elucidate the effects of talc on gravure printability, model papers were produced with three kinds of coating talc whose particle size and brightness are different. Physical properties related to surface and structure and the gravure printability of the sample were tested. Coating color with talc showed lower viscosity than that with clay. For both matte and art grades, talc tended to give lower gloss than day. The smaller the particle size of talc, the better properties in the coating color viscosity and water retention. When the particle size of talc was small enough, the surface roughness of the coated paper produced with talc was similar to that with clay while larger talcs produced rougher surface than clay. On top of that, application of talc improved compressibility and gravure printability of coated paper.

• 펄프종이기술
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• 제39권1호
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• pp.48-55
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• 2007

The aim of this article is to review the general property of the famous traditional Korean paper, "rice straw paper"(Bast-Fiber mixed with straw pulp), and to compare the paper qualities varying with the composition ratio of straw pulp, in order to revive the traditional paper in modem Korea. The experiment was carried out by making first the two different mixture papers, i. e., one is the paper of 50% bast fiber mixed with 50% straw pulp, and the other is the paper of 75% bast fiber with 25% oats straw pulp, and finally the 100% bast fiber paper was made for the purpose of comparison. The qualitative properties of these three kinds of paper with the different mixing ratio of the straw pulp were evaluated, and the findings of the experiment can be summarized as follow: 1. As to the quality aspects of the paper strength like tensile strength, breaking length, elongation, and tear strength, the test proved the 100% bast fiber paper as best, and the 50% mixed paper as the next good one. 2. In aspect of the printing adaptability such as density, opacity, brightness, whiteness, lab colors, air permeability, and roughness, the 50% mixed paper proved to be the best, due to the short cells in the straw pulp. 3. As to the air permeability, the larger ratio of straw pulp was found to be the lesser, and 75% bast fiber with 25% straw pulp mixture paper and the 100% bast fiber one were found 1/5 degree efficient. 4. In terms of the water absorption degree, 100% bast fiber paper was the fastest, but in case of mixture paper, 50% mixed one was a little faster up to the point of 1cm, while the two kinds of mixed ones appear to be almost similar to each other beyond the point. 5. The straw pulp mixed paper, especially the 50% mixed one was evaluated as the highest by the calligraphers who had experienced using the papers in terms of movement and feeling of the caligraphy and painting. In addition, although the 25% mixed paper is judged to be good for book printing because of the strength, the 50% mixed paper can be thought to be more desirable for painting and calligraphy. In conclusion, we will be able to make the quality paper with durability, by mixing the straw pulp with the bast fiber in proper ratio, following the tradition of Korean paper making.

• 한국소음진동공학회논문집
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• 제20권11호
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• pp.1018-1024
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• 2010

The printer noise consists of the noise of the various components and parts such as motor, fan and solenoid. And the human's printing sound recognition shows various aspects when the printer starts to print papers because the components operate at the same time. Especially, printers are usually installed in the quiet office room. Therefore the printing noise is related to its competitiveness in the market. The importance of the printer sound qualities is increasing and it is necessary to develop the sound quality evaluation system, so it is a key point to identify the noise source of the printer and develop the sound quality index to each component. By using this evaluation system, it is possible to evaluate the sound quality of a prototype printer compared to the already existing one. In this paper, the printer sound quality evaluation system was developed by the following steps. Firstly, the signal processing method was applied to the recorded printing sound to identity and split the noise of components. Secondly, the MLR(multiple linear regression) method and the psychoacoustics were used to develop the sound quality index. Finally, the improvement of the printer sound quality is possible by using the result of the MLR and the path analysis. The output of this research will be applied to the development of a new printer.

• 펄프종이기술
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• 제37권5호통권113호
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• pp.70-77
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• 2005

The development of printable Hanji is regarded as an important work to create a new demand of Hanji in information-oriented era. Hanji has rougher surface, huger absorption of ink and lower optical properties and printabilities than common printing papers. Improving those shortcomings of Hanji is required to be printable Hanji. Sizing and calendering have known as a way to make properties of paper good. Accordingly, this research was performed to find out useful sizing agents for reforming its drawbacks. Four sizing agents (CMC, com starch, PVA, AKD) were used in this research. The optical properties and the printabilities of sized Hanji were tested. The obtained results were as follows. Based on concentration, each sizing agent was prepared. These were CMC(0.5, 1, $1.5\%$), corn starch(1, 2, $3\%$), PVA(1, 5, $10\%$), AKD(0.5, 0.1, $0.15\%$) respectively. After sizing, we performed calendering treatment with pressure of 0.5, $1\;kgf/cm^2$. All the sizing agents and calendering treatment improved the properties of Hanji to some extent. Particularly, com starch was good for gloss. In case of printability, $1\%$ AKD with $1\;kgf/cm^2$ was recommendable for typography ink density, $3\%$ com starch with $0.5\;kgf/cm^2$, inkjet ink density, $2\%$ com starch with $0.5\;kgf/cm^2$, inkjet ink girth. PVA and AKD without calendering were counter-effective agents for inkjet ink density. Printable Hanji is required to have not only better surface strength enough to appear non-picking, higher ink density and lower show-through than base paper but also the lowest ink girth in comparison with base paper. When referring to them, efficient sizing agents were regarded as $0.1\%$ AKD with $1\;kgf/cm^2$, calender pressure, for typography printing and $2\%$ com starch with $0.5\;kgf/cm^2$, calender pressure, for inkjet printing.