The focus of this study has been put on visibility of local density unevenness without periodical features. It has been found that one of characteristics affecting the visibility and being on original images was the spatial frequency of lightness distribution in an area with the approximately same size as the unevenness. However, the characteristic had less versatility since the method to calculate it depended on features of the unevenness. To improve the point, methods to extract an original-image's characteristic affecting visibility of unevenness has been suggested. Furthermore, a correlation model between the characteristic and the visibility has been proposed. The model could be shown that it was applicable when the width of unevenness image was below 2° of visual angle. A correlation model creation for unevenness images with more than 2° width was not been achieved and it would be a work to be addressed in the future.
We have been developed the optical imitation model of human skin. The model demonstrated that the long-wavelength side of a visible light caused multiple reflections and the propagation range were very wide. The long-wavelength side of a visible light including red and yellow is important for the skin color image, so the evaluation of the light propagation of real human skin is worth much for developing basic theories of semitransparent objects like skin. The length of the light propagation of human skin were detected using red, green and blue lasers, and the red laser light propagated 54mm which was longer than green and blue. Our results were well matched for our previous optical imitation models.
Small ink droplets called ink mist contaminate important parts of an inkjet printer. It is important to clarify the mechanism of ink mist generation and ink mist behavior in the printer for suppression of ink mist contamination. In order to investigate the influence of airflow to ink mist generation, we observed ink mist behavior and measured velocity field of airflow between a printhead and paper. It has been clear that the amount of ink mist increase with the increase of scan speed and ejecting pitch due to the increase of the airflow velocity of ink mist carrying and the decrease of the downward airflow velocity. Moreover, diffusion process of ink mist in the printer has been clear by the simulation combining air flow calculation and particle calculation. In addition, it showed that the calculation result of the influence of moving flexible bodies on the ink mist adhesion distribution in the printer corresponds to the measurement result.
Inverted organic light-emitting diodes (inverted OLED) with a bottom cathode have been extensively studied as an alternative to conventional OLED. The main advantage of the inverted OLEDs is that the inverted OLEDs avoid the use of reactive cathode (e.g., Ca, LiF) and therefore allow the preparation of the inverted OLEDs without rigorous encapsulation. In this study, solution processable inverted OLEDs were fabricated using polyethyleneimine (PEI) with different ratios of primary, secondary and tertiary amines as an electron injection layer. The best current efficiencies of the inverted OLEDs with three different PEIs, P-1000, SP-200 and SP-003, are 9.0, 9.4 and 11cd/A, respectively. Photovoltaic measurements revealed that the improvement of the current efficiency of the inverted OLEDs with SP-003 is attributable to the lowering of the electron injection barrier. The optimization of chemical structures of PEI is key importance for the improvement of the current efficiency of inverted OLEDs.
Understanding the microscopic charge distribution on a toner surface has been a significant issue in electrophotography to ensure accurate control of toner behavior. However, research has been limited to theoretical investigations of the adhesion force or the effect of the material composition, which are insufficient to examine the influence of the electrophotography process on the charge distribution. We investigated the effect of discharge phenomena on the charge distribution of transfer residual toner using a combination of Kelvin probe force microscopy, which can image the charge distribution on a toner surface, and microelectromechanical systems-based actuated tweezers, which can manipulate toner particles and estimate the charge center on a single toner particle. Changes in the microscopic charge distribution and the charge centers of transfer residual toner were analyzed based on the transfer current. The results show charge inclination induced on a single particle by a discharge around a transfer nip.
Kapok fiber is a natural half-transparent hollow tube with 18 and 20 micrometers of inner and outer diameter respectively and the hollow rate of 80% and over. We have tried to make paper sheets integrating Kapok fibers containing functional materials such as magnetic materials or chromic materials for anti-counterfeit or rewritable paper respectively. The making process of these functional paper sheets consist of including process of the functional material solution into kapok fiber's hollow part, and therefore the affinity among functional material, solvent and kapok fiber's inner wall is considered to be an important factor at the including process. In this present work, focusing on Hansen Solubility Parameter and work of immersion on the kapok fiber's inner wall as important factors, we examined optimum combinations of the solvents and surface treatments of the kapok fibers for the functional material's inclusion, using acethylation-treated kapok fibers and untreated kapok fibers.
In previous simulations of carrier mobility performed for molecular design of charge transport materials, the charge transport rate constant has often been calculated using the Marcus theory, and the electronic structure of an isolated pair of molecules has been simulated with a molecular orbital method. However, it is desirable to consider the embedding electrostatic potential to obtain realistic properties of amorphous charge transport materials, so that the carrier mobility can be evaluated by applying the transport theory to each molecular pair. In this study, we employ the fragment molecular orbital (FMO) method to calculate the electronic structure of a molecular system combined with the kinetic Monte Carlo (KMC) method to model charge transport phenomena. The calculated carrier mobility of amine-based charge transport materials is in a qualitatively good agreement with experimental values.
Owing to the strong affinity to human being, paper media have higher hedonic values that lead to the unique characteristics of “cognitive scientific dominance”. However, in the present digital information society, it is not easy task to foresee the future of paper media based on the conventional viewpoints of market, business and technology.
This paper attempts to provide a variety of new insights into the essences of paper media using innovative manners, that is “Human science”. Interaction between man and paper is simplified as “human-goods relationship”. The essence of paper was analyzed from physical, psychological, philosophical, and sensory viewpoint. For further increase of the affinity, psychophysics is required in the design of paper media. These analyses help elucidating the essentials of “Power of paper” and that the essential areas indispensable of paper media in the contemporary digital society. Overall contents help understanding theoretically the significance of the existence of paper media.
The fine structure of each fiber which forms the paper, is the answer. Regarding the three major advantages of the pulp and paper industry, firstly paper is good for the global environment. Wood fiber biosynthesized by carbon dioxide assimilation is the raw material of paper, and according to the concept of carbon neutral, as long as the same amount of the use trees are planted, paper can be concluded to be good for the earth. Second, the pulp and paper industry is the biggest biomass energy producer in the country. The amount of electricity generated by the black liquor of all the paper industry in our country corresponds to 2.5 nuclear power generation plants, and the industry is also the biggest biomass energy consumer who overwhelmed other industries. Thirdly, the fact that paper is a super long-term information storage medium is that the Shosoin document has been preserved for over 1200 years, even now it is possible to read the written letters and to appreciate the paintings drawn This fact this proves this advantage.
The authors have developed the inkjet paper by the selection of optimum ink fixative, the setting of optimum range of ink fixative volume and size press coat weight in order to add the quality of each grade required for the inkjet paper.
Mass communication is heading toward personal communication in a digitalized society. Does “the value of the paper media” change with that? We illustrate fundamental, basic configuration, and its materials regarding paper for the re-definition, and reconsider the good aspects of paper media from the view point of cognitive engineering, neuroscience and so on. Furthermore, we mention that using paper is more earth-friendly. As for the current printing market from the US and Japan, “the value of paper” is now being re-evaluated. Because the paper media is a device sensuous to the human five senses. Many marketers realized that particularly, catalogues, brochures, and direct-mails are much stronger tools to impress customers than the web marketing alone. And we think about the future of the paper media.
This paper discusses two questions of why paperless office does not come and where paper is used in the future. The reason for the first question is that most work flows of approvals and applications are still processed with paper and are not digitalized in small companies or organizations. The digitalization of the work flows needs the introduction of companies' backbone system and employee training. Moreover, if organizations cannot manage going paperless well, the productivity of work might be deteriorated against their expectations. Therefore, we expect that the progress of going paperless would be slow in the future. Regarding the second question, strengths of paper is due to easiness to handle of paper and it is supported by the physical affordance of paper. It is difficult for digital media to mimic the physical affordance of paper. Therefore, we expect that paper would be used in scenes where the physical affordance of paper plays an important role to perform tasks.
There are increasing scenes where digital printing is done in the printing industry in Japan. However, it is not an exaggeration to say that there is no significant increase trend. For example, in publications, there are increasing cases in which books are certainly made by digital printing, especially in small copies of 100 copies or less. But, the proportion is less than 0.1% by the author's imagination.
In the United States I hear that digital printing is successful, but in Japan it is not like the United States. Why do not prints by digital printing or digital printing increase?
In this paper, we will consider how digital printing is used. And we will also introduce examples of printing companies working on digital printing.