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Ozaki Y.,National Printing Bureau of Japan
Journal of Adhesion Science and Technology | Year: 2010

Many kinds of adhesives are used to produce paper and prints. However, it is difficult to observe the distribution of these adhesives in situ because most are transparent and of low content. We have developed a fluorescence staining technique, which observes adhesives in paper with a confocal laser scanning microscope (CLSM) after staining with specific fluorescent dyes. In this review, we present our observations using this technique on a wet strength resin in paper, the vehicle of offset printing ink on uncoated paper, and the coating binder in coated paper. The polyamide epichlorohydrin (PAE) resin, a wet strength resin, was selectively stained with Sulforhodamine 101 acid chloride, while the pulp fibers were stained with Acridine Orange. The distribution of PAE could be observed in a CLSM fluorescence image at the excitation wavelength of 543 nm, and the pulp fibers could be observed in a fluorescence image at the excitation wavelength of 473 nm. From this it was found that PAE tends to concentrate at fiber crossings. In order to quantify the penetration of the ink vehicle into the base paper sheet, cyan offset inks stained with Rhodamine B were printed on various paper samples. The location of the vehicle was determined with CLSM. The penetration of the ink vehicle was observed in three-dimensional images. Coated papers were soaked in a solution of Rhodamine B in ethanol, and then they were rinsed with pure ethanol. The styrene-butadiene latex of the coating binder was selectively stained with Rhodamine B. The distribution and position of latex in the coating layer was characterized with CLSM. © 2010 Koninklijke Brill NV, Leiden.

Hamada H.,National Printing Bureau of Japan | Bousfield D.W.,University of Maine, United States
11th Advanced Coating Fundamentals Symposium Proceedings: The Latest Advances in Coating Research and Development | Year: 2010

Nano-fibrillated cellulose (NFC) has the potential to be produced from wood fibers at low costs. To determine the potential of NFC to be used as a coating material, the characteristics of several NFC coated samples on a synthetic fiber sheet are reported. Two water-based printing methods were used to characterize the change in print quality. Two types of NFC were prepared by two different physical treatment methods. Various coat weights were applied onto synthetic fiber sheets. The printability of the coated sheets was evaluated by ink absorption rates and print density. Ink pigment penetration is characterized with a Confocal Laser Scanning Microscope and a Scanning Electron Microscope with chemical analysis with Focused Ion Beam to prepare samples. The contact angle and the ink penetration rates decreased with increasing the coat weight of NFC. This result is the opposite of what the Lucas-Washburn equation would predict; a decrease of contact angle should increase capillary pressure and absorption rate. The ink pigments were captured by the NFC layer and held near the surface, increasing the resistance to fluid penetration. For pigment based flexographic inks, ink pigments were captured at the NFC layer. For dye based inks, the ink components penetrated and moved through the NFC coated layer. For the ink-jet printing, the print quality improved with the NFC coating. The pigments in ink-jet ink were captured near the surface, even though the pigments are nanometer in size. Synthetic fiber sheets coated with NFC did improve in terms of printing resolution and ink density, especially for pigment type inks.

Fukuda S.,National Printing Bureau of Japan | Chaussy D.,Laboratory of Pulp and Paper Science and Graphic Arts LGP2 | Belgacem M.N.,Laboratory of Pulp and Paper Science and Graphic Arts LGP2 | Reverdy-Bruas N.,Laboratory of Pulp and Paper Science and Graphic Arts LGP2 | Thielemans W.,University of Nottingham
Applied Surface Science | Year: 2013

Commercial oil-proof papers containing new family of fluorochemicals were characterized in terms of surface and barrier properties and printability. XPS analyses demonstrated that the fluorochemicals added to these papers had shorter perfluoroalkyl chains, compared to those used few decades ago. Contact angle measurements were performed and the obtained data were processed according to Owens-Wendt-Rabel-Kaelble (OWRK) approach, in order to calculate the surface energy of the investigated samples. This set of experiments revealed that the values of the surface energy of the non-coated surfaces of oil-proof papers were low enough (i.e. about 5 mJ/m2) to repel both water and oil. The surface energy of the coated sides was, instead, close to that of classical organic surfaces (i.e. around 30 mJ/m2), which predicts their potentially good printability. In fact, microcontour test was performed as the basic test for evaluating printability of oil-proof papers and showed that ink pigment retention was not significantly influenced by the level of barrier to oil. However, the surface roughness was found to play a key role in such properties. © 2013 Elsevier B.V. All rights reserved.

Yamakoshi M.,National Printing Bureau of Japan | Rong X.,California Polytechnic State University, San Luis Obispo
Proceedings of the Technical Association of the Graphic Arts, TAGA | Year: 2012

Conventional test methods for determining drying time of printing inks are subjective. The comment methods involve finger swiping and visual assessment or accompanied complicated procedures by rubbing tester with destruction of samples. These methods encounter difficulties in qualifying the extent of drying, thus, seem to be restricted to obtain comparative data of drying property. In this paper, the methodology of determining the drying time of inks on substrate by monitoring reflected speckle patterns arisen from ink surface by laser illumination was discussed. The dynamic alteration of speckle patterns corresponds to the fluctuation of microscopic structure of the ink surface with penetration and evaporation of dispersion elements. The methodology assumed when the correlation coefficient of successive speckle patterns captured by CMOS camera at a certain time interval is in a stationary state, the ink film is considered as dried. The method is objective, noncontact, and inexpensive. The experimental data of inks drying measured by the speckle method were compared with the result by ASTM F2498 for inkjet print and JIS K5701 for drawndown offset ink. The comparison results showed that the speckle method has good correlation for different media with ASTM F2498, however no significant relation with JIS K 5701 which leads to transference of the undried inner ink rather than surface. The reflective speckle is limited to observe the surface area of ink films. Transmitted speckle patterns of samples should be investigated to improve conformity test purpose as a future work.

Shimura H.,National Printing Bureau of Japan | Shimura H.,Tokyo Medical and Dental University | Wakabayashi Y.,Tokyo Medical and Dental University | Nimura A.,Tokyo Medical and Dental University
Journal of Orthopaedic Science | Year: 2014

Background: Some patients with mallet fractures who undergo extension block pinning complain of exposed wires, which delay their return to sports and causes inconvenience while performing tasks that require the use of hands during the early postoperative period. The purpose of this retrospective study was to present and evaluate a novel surgical procedure for mallet fractures. Methods: We treated 20 patients (14 males and six females; mean age, 38.4 years; range 17-68 years) with displaced mallet fractures involving >30 % of the articular surface using the closed reduction and microscrew fixation between January 2009 and January 2012. The distal interphalangeal joint (DIP) joint was immobilized with a splint for 1-3 weeks on an individual case basis. According to Wehbe and Schneider's classification, there were 12 type IB, six type IIB, and two type IA fractures. The mean follow-up duration was 12.6 months (range 6-31 months). Results: Bone union was achieved in all patients within a mean period of 6.8 weeks, with no incidence of infection, skin necrosis, permanent nail deformity, or secondary osteoarthritis. Only two complications - temporary nail ridging in one patient and a dorsal bump caused by the screw in one patient - were observed. Minimum postoperative displacement was observed in one patient, for whom immobilization with a splint was continued for 4 weeks. Articular incongruity was <1.0 mm in four patients and 1.0-2.0 mm in two patients. Mean DIP joint extension loss was 6.5° and mean flexion was 67.8°. The surgical outcomes were excellent in seven patients, good in nine, and fair in four according to Crawford's evaluation criteria. Conclusion: Our novel surgical procedure combining closed reduction with extension block and flexion block using Kirschner wires and microscrew fixation produces good clinical results with relatively few complications. © 2014 The Author(s).

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