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Ink receptivity on paper — characterization of paper materials
Abstract
The rheological behaviour of three black offset inks was tested using viscometer with the cone and plate geometry. The shear stress versus shear rate measurements confirmed that the investigated offset inks represent similar viscoelastic, pseudoplastic fluids, forming thixotropic structure. Mileage and ink transfer curves were measured onto the paper materials with different properties. The analysis of experimental results using Tollenaar–Ernst and modified Walker–Fetsko equations established the substantial role of the paper characteristics such as smoothness, brightness and penetration in the process of ink film formation on paper substrates during printing.
... where m represents the slope of the curve [(dD/D ∞ )/dz] in the region of a very thin ink film thickness, z. Havlínová et al (2000) investigated the ink receptivity of paper with offset inks. They applied the Tollenaar-Ernst equation to their experimental data when studying ink mileage for the different papers. ...
... SSE), and the different substrates gave different transfer ratios, at least when the anilox roll 120 lines/cm was used. It is not surprising to find variations in transferred amounts, since the surface energy and viscosity differ for the liquids, and the surface energy, roughness, formation and porosity differs for the substrates and it is known that these properties affect ink transfer (Darhuber, 2001, De Grace 1983, Frøslev-Nielsen, 1962and Havlínová 2000. ...
... Biomass such as wood, palm kernel and coconut has for many years been used for the production of powdered activated carbons but none has been reported in usage of PKC as black ink pigment source. Physical pyrolization involves pyrolysis of the source material to produce a black carbon [1,2,4]. The source in ink at the level to find an acceptable printing evolution derived from PKC is now motivated. ...
... The right viscosity of ink mixture will enable ink to be absorbed well on paper. The ink used in printing process is subjected to a high degree of shear on a roller system of a printing machine [4,5,8]. ...
Recycling the waste from natural plant to produce useful end products will benefit many industries and help preserve the environment. The research reported in this paper is an investigation on the use of the natural waste of palm kernel cake (PKC) to produce carbon residue as a black carbon for pigment source by using pyrolysis process. The activated carbons (AC) is produced in powder form using ball milling process. Rheological spectra in ink is one of quality control process in determining its performance properties. Findings from this study will help expand the scientific knowledge‐base for black ink production and formulation base on PKC. Various inks with different weight percentage compositions of AC will be made and tested against its respective rheological properties in order to determine ideal ink printing system. The items in the formulation used comprised of organic and bio‐waste materials with added additive to improve the quality of the black ink. Modified Polyurethane was used as binder. The binder’s properties highlighted an ideal vehicle to be applied for good black ink opacity performance. The rheological behaviour is a general foundation for ink characterization where the wt% of AC‐PKC resulted in different pseudoplastic behaviors, including the Newtonian behavior. The result found that Newtonian field was located in between 2 wt% and 10 wt% of AC‐PKC composition with binder. Mass spectroscopy results shown that the carbon content in PKC is high and very suitable for black performance. In the ageing test, the pigment of PKC perform fairly according to the standard pigment of Black carbon (CB) of ferum oxide pigment. The contact angle for substrate’s wettability of the ink system shown a good angle proven to be a water resistive coating on paper subtrates; an advantage of the PKC ink pigment performance.
... One of the most important properties of paper is its ability to control the penetration of ink. Surface topography is often critical to ink penetration depth, which plays a major role in determining print gloss, print density, and the appearance of the final printing (Bohuslava et al. 2000). AFM has been used to obtain the three-dimensional characterization of surface topography of paper; and the findings provide the basis for numerical analysis (Udupa et al. 2000). ...
The penetration of ink into paper affects the final appearance of printing and the amount of ink usage. In this work, UV-curing fluorescent rose ink was used to investigate the penetration and distribution of the ink pigments as well as their correlation with the surface topography of paper. The ink penetration and distribution were characterized with Confocal Laser Scanning Microscopy (CLSM), whereas the microstructure of the paper surface was observed using Atomic Force Microscopy (AFM). The AFM results showed that the surface of the paper coated with kaolin layer was the smoothest among the samples. Also the pore size of the calcium carbonate coating layer was smaller than that of the kaolin coating layer. Meanwhile, the pore size distribution of the calcium carbonate coating layer appeared to be relatively narrow, compared with other samples. The results of CLSM images indicated that the depth, size, and arrangement of pores affected the penetration depth and distribution of ink pigment on coated paper. The large pores led to deeper penetration of ink pigments, and uniform ink absorption occurred when the pore distribution was uniform. The UV-curing ink pigments not only set on the surface of the uncoated paper, but also they penetrated into the paper interior and adhered to the fiber surface.
The paper surface efficiency is the physical measurement of the paper gloss and ink absorption ability, it is also the paper printing eligibility index related to the optical properties and the quality of printing products. We chose the different types of paper, print paper with three kinds of primary color ink and test the color strength, color deviation, gray level and color efficiency. We also analyzed the relationship between paper surface efficiency and ink color effect to provide data reference for practical production. The experimental results showed that the surface efficiency of the paper has great influence on the ink color effect. The paper with good surface efficiency has great ink reproduction performance, while the paper with poor surface efficiency has poor ink reproduction performance. Therefore, the actual printing should be based on the need and choice of suitable paper. High gloss paper should compensate with high absorbency and low gloss paper need to compensate with low absorption in order to improve paper surface efficiency and get printing products of high quality.
In the present study, test prints were performed to establish the effects of printed ink colors on L*a*b* values. For the test prints, two kinds of papers ie. rough surfaced uncoated white paper and gloss coated paper and a physically drying oil based offset printing ink suitable for these two papers were used. In the optimum printing room conditions, a background print was applied in cyan color on the papers by an IGT C1 offset printing machine. L*a*b* values were measured by spectrophotometer immediately and following 6 hours drying time. The effect of paper surface roughness on the L*a*b* values in the ink printed on uncoated white and gloss coated papers were practically established. In the light of the observations, the precations to be taken were given in a rapidly performed printing work ie. newsprint in order to obtain standard L*a*b* values with the uncoated slightly papers.
Çalışmada kağıt yüzey pürüzlülüğünün, üzerine basılan mürekkep renklerinin L*a*b* değerleri üzerine etkisinin tespiti için test baskıları yapılmıştır. Test baskıları için yüzeyi pürüzlü 1. hamur beyaz kağıt ve pürüzsüz sayılabilecek kuşe kağıt ile bu kağıtların ikisine de uygun olan fiziksel kuruyan yağ bazlı ofset mürekkebi kullanılmıştır. Optimum baskı odası şartlarında IGT C1 ofset test baskı makinesi ile kağıtlar üzerine cyan renkte zemin baskısı yapılmıştır. Test baskıları üzerinde baskı sonrası hemen ve tam kurumanın gerçekleştiği 6 saat sonra spektrofotometre ile L*a*b* değerleri ölçüldü. Pürüzlü ve pürüzsüz kağıtların üzerine basılan mürekkeplerin ıslak ve tam kurumuş haldeki yapılan ölçümlerinin değerlendirilmesi sonucunda kağıt yüzey pürüzlülüğünün L*a*b* değerleri üzerine etkisi uygulamalı olarak tespit edilmiştir. Bulgular ışığında yüzeyi pürüzlü kağıtlar üzerine yapılan baskılarda standart L*a*b* değerlerinin elde edilebilmesi için, gazete gibi çok hızlı gerçekleştirilen baskılarda alınabilecek önlemler verildi.
In the front/back solid colour print of newsprint papers that have a porous, unstable structure, the colours deviate from one another. In the study, cyan and yellow colours of inks from the process print colours to newsprint paper and the colour variation that is constituted in the front/ back solid colour print coinciding one after the other was examined by comparing the actual colour CIE L*a*b* values to the NAA (Newspaper Association of America) Standard Gamut CIE L*a*b* values. Keeping the newsprint paper stable, the application of front/back ground colour test print was performed by the ink in 5 diferent grammages. In order to acquire the L*a*b* values of the ground colour process dyes that are close to standard values with the amount of ink changing, the amount of the optimum film ink to be applied to m2 on the newsprint paper was also determined. In order to determine the penetration depth of the ink which can not be determined mathematically due to the unstable structure of the newsprint paper, the interface structure of paper-ink was evaluated by being monitored on Stereo Microscope and SEM.
The influence of corona-treatment and surface roughness on print quality was studied for two polyethylene coated paperboards of different surface roughness, printed with a water-borne flexographic ink. The surface energy of the ink was varied by addition of a surfactant. The results illustrate the significance of the surface roughness on the print quality and the significance of the corona-treatment on the rub resistance. The surface energy of the ink did not affect the print quality.
Estimating of technological allowances for sheetfed offset printing is a difficult task, taking into account the large quantity of printing process parameters, but also because some of the calculations must be done before a precise job information is gathered. Currently accepted models for estimating technological allowances are based on statistical data. Many of them, however, were built with data from machines of different construction and equipment than currently used. With lower order quantities and the implementation of significant automation in printing presses, this leads to overestimation of material (paper) quantity required and consequently the adoption of higher production costs than actually possible. This dissertation presents a different approach to estimating allowances, that was developed based on the theory of dimensional analysis and processes similarity. The dissertation is based on the assumption that it is possible to relate the number of technological allowances to a large number of job and materials parameters, as well as the printing process information. Theoretically derived dependencies were then matched to the experimental data, i.e. information about the actual technological allowances (waste sheets) collected during the production of actual job orders in printing plants. For this purpose, the method of multivariate linear regression was used. The calculations were made for each of the three main types of paper used in sheetfed offset printing (uncoated paper, coated paper, cardboard). The results of calculations indicate that some parameters have much smaller effect on the actual number of waste sheets the offset printing than currently assumed, while for various types of substrates a different set of parameters affecting the technological allowances shall be used. In addition, similar calculations for individual presses make possible the development of technology standards for individual cases, taking into account press design, equipment and its role in the printing plant. The standards developed in this way can also provide input for the quality control systems. A method presented in the dissertation, based on data collected during the operation of printing presses in the company, allows continuous adjustment of standards along with the changes in the production profile, as well as in the equipment used. The indicated similarity numbers allow for a more complete characterization of the printing process for the sake of press operation and allow comparison of individual job order production. The method of estimating technological allowances, which with the dependence on the job order parameters, may also be useful in the optimization of the operation of machinery through the choice of the press in order to minimize losses – and thus costs – while printing the given job. The study includes a discussion on the application of its results for the choice of analog or digital printing techniques, assuming that for each of these techniques the quantity of waste sheets depends on the order parameters. This dissertation proposes also a method of determining the threshold quantity, i.e. the job quantity, for which the production costs in both possible printing techniques are identical, that is based on the technological allowances. This method can be used for optimal selection of the printing method for the given product batch.
The objective of this experiment was to investigate the relationship between binder migration and ink penetration using atom force microscopy and laser scanning confocal microscopy. The different drying temperature was used to change binder migration. Binder migration was observed using atom force microscopy. Fluorescent ink was used to observe and characterise ink penetration and distribution by laser scanning confocal microscopy. Reconstructed images were used to describe ink penetration in the coated paper by laser scanning confocal microscopy. The results implied that it was reliable and effective using laser scanning confocal microscopy to characterise ink penetration depth and distribution uniformity. This method could not damage the specimen, and did not need fluorescent dye to stain the specimen. The results indicated that binder migration affected ink penetration depth and distribution evenness. More binder migration to the paper surface could not contribute to ink penetration and even ink absorp...
Cutting is a relative accurate method in the literatures about ink penetration measurement at present. But cutting may bring some damages to paper, which reduces reliability of measurement result. The objective of this experiment was to investigate the influence of coating thickness on ink penetration and characterize the penetration depth through quantitative analysis by Laser Scanning Confocal Microscope (LSCM). Fluorescent ink was used to observe and characterize ink penetration by LSCM. Three-dimensional images of ink pigment penetration were obtained by reconstructing all XY plane images. The results implied that it was reliable and effective method using LSCM to characterize the ink penetration depth and distribution uniformity. It could be concluded that the print quality could be adjusted and improved by increasing the coating thickness.
Ink is transferred and sets onto the paper surface in the printing process, which affect printing quality and usage of ink. The objective of this experiment was to investigate the influence of ink type on ink absorption and characterize the penetration depth through quantitative analysis by Laser Scanning Confocal Microscope (LSCM). Fluorescent ink was used to observe and characterize ink penetration by LSCM. Three-dimensional images of ink pigment penetration were obtained by reconstructing all XY plane images. It could be concluded Common offset printing ink compared with UV offset printing resulted in deeper ink penetration ,uneven ink distribution and lower print density. Because the composition and drying method of UV offset printing ink and common offset printing ink were significant different, penetration depth and distribution uniformity of these two types of offset printing ink in coated paper were distinct.
The standard moist heat (80 °C and 65% relative humidity) and dry heat (105 °C) techniques of accelerated paper ageing were applied in stability investigations of offset ink films printed on alkaline offset paper. The measured characteristics of paper sample evidenced its first-class mechanical properties, large alkali reserve, in addition to high values of brightness and opacity. The pseudoplastic flow behaviour was established for original offset CMYK printing inks by rheological measurements. The results obtained, following application of both ageing procedures, revealed the significant exponential decrease of relative optical density for MAGENTA and YELLOW ink layers. The variance in visible reflectance spectra and in total colour difference ΔE* (L*a*b* CIE) of ink films evidenced the considerable damage of CYAN and YELLOW ink films, especially upon moist heat treatment. The differences in lightness ΔL* play the dominant role in ΔE* values of BLACK ink films upon both ageing procedures. The FT-IR spectroscopy was additionally used in the characterization of paper, inks, as well as ink films on paper before and after ageing.
The Walker-Fetsko ink transfer equation is difficult to fit to data for uncoated papers using the linear plot technique. Resulting errors in evaluation of transfer parameters are substantial. Four other mathematical methods are described which give much more accurate results. The methods include correcting for the curvature of the plot, extrapolations to x equals infinity , plotting f vs. b, and using computer searching. Use of these methods is very important for use of the transfer constants and for comparison of different ink transfer theories and equations.
The thin film processes of the sputter deposition method have been reviewed with special emphasis on the effects of kinetic energy of sputtered particles and ion bombardment during deposition on thin film properties. An overview is first given to describe the thin film process and ion-surface interactions, where the methods of measuring the energy distribution of sputtered ions and the anisotropic-emission-effect sputter deposition are presented. Experimental results for Cr, SiO2 and Ni-Si-B films are presented, and the correlation between the structure and properties of the thin films is discussed. Research in modification of thin films by energetic atoms and ions is an exciting area of materials science in the future.
On the assumption that pseudoplastic flow is associated with the formation and rupture of structural linkages a new flow equation is derived. The equation takes the form where D = rate of shear, η0 = limiting viscosity at zero rate of shear, η∞ = limiting viscosity at infinite rate of shear, and α is a constant associated with the rupture of linkages.Graphical methods for evaluating the three constants η0 , η∞ , and α are presented.Experimental data are presented on a wide range of pseudoplastic systems, ranging from suspensions to optically clear solutions, in both aqueous and nonaqueous media. In all cases the results conform to the equation with a high degree of accuracy over a wide range of shear rates.
The authors provide a rigorous general equilibrium analysis of the welfare effects of international trade in the presence of differentiated home nontraded products as well as tradable products. They extend the standard monopolisitic competition framework to incorporate differentiated nontraded products and demonstrate that, in general, the gains-from-trade proposition applies also to this framework. However, the authors also show that trade may reduce the variety of home products and, thus, abstracting from all sources of gains from trade other than variety effects, they show that only in a very extreme case trade may make all countries worse off.