This report showed the practical applications of the surface state theory to the evaluation of electrophotographic developers. It was proposed that the work functions and the surface state densities of toners and carriers should be relatively evaluated by using the parameters obtained through the regression analysis of the measured data of the specific toner charge as well as the mixing ratio of toner to carrier. Moreover the relative evaluation method for the work function distribution of toners was examined. As a result, the range of the work function distribution of toners was evaluated by using the above parameters and the threshold mixing ratio of toner to carrier at which the wrong sign toners begin to generate from the developer. The surface state theory was shown to be utilized effectually for the evaluation of developers.

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Based on the surface state theory, a definite equation for the time constant of toner charging was derived by formulating the dynamic charging equation. The time constant was expressed by the parameters obtained through regression analysis of the measured data of the specific toner charge as well as the mixing ratio of toner to carrier. The equation showed that the reduction of the time constant was quantitatively predictable.
The relationship among the work functions of toner and carrier and the corresponding time constant was analyzed on the assumption that the distributions of surface state densities are exponential to electron energy level. This analysis successfully explained the experimental result that the logarithm of charging speed (inverse of the time constant) is proportionate to the difference in work functions between toner and carrier.
The surface state theory was shown to be effectually utilized not only for the evaluation of developers but also for the design of materials for developers.

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In this paper, we propose a hyper spectral sensing method to be applied for color printer development. It was found that the data obtained from this method can be applied in the development of color printers, especially in the view point of quantitative evaluation for color image quality. As an example, we proposed an evaluation function for “Metamerism”, a spectral color difference, with using the hyper spectral data. By applying the evaluation function to printed test samples, it was also confirmed that the obtained data was effectively used in quantitative color difference evaluation. Using the wide band feature of hyper spectral sensing, it was also found that the method is effective to analyze materials of printing papers and ink, such as moisture content and the kind of fibers…etc.

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The aim of this paper is to evaluate the several adaptabilities such as charging, developing and fusing characteristics of sample toners in order to be applied to as the toner of electrophotographic system on the condition of a low temperature. We make four kinds of sample toner having a different pigment addition by using copolymerization method. Then, we encapsulate each toner in order to get sample toners having a same core structure.
Charging amount of sample toners was tested. Flow measurements were carried out sample toners in order to clarify their rheological characteristics. Printability tests of fusing methods were conducted. Also evaluation of image quality was carried out to investigate development characteristics of sample toners using by laser printer.
In spite of micro-encapsulating treatment of sample toner, it was possible to get at least -30μC/g of charging amount. Since, micro-encapsulating treatment was a main reason to decrease the charging amount of sample toners. We found out that it is possible to get the good charging and development characteristic of micro-encapsulated toner for printing test using by laser printer. It is believed that addition ratio of pigments on copolymerization of the sample toner have a strong influence with the variation of the fusing characteristic and oozing behavior of internal resin through capsule wall.

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Under rapid technological innovation and price decline, white LEDs and OLEDs are just beginning to be applied to lighting. In this paper, Current status and challenges of LEDs and OLEDs towards future lighting market are summarized.

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As luminous efficacy of white LEDs improve, white LEDs are expected to contribute to energy saving of lighting, and are used widely as light sources for indoor and outdoor lighting. However, white LEDs are semiconductors and the principle of light emission of white LEDs is different from those of existing light sources so that the color appearance under white LEDs may be different from the existing light sources. Here I compare the differences between the existing light sources and white LEDs, and then introduce the current method of CIE/JIS color rendering evaluation and the color rendering of LED lighting. In addition, I introduce a trend of CIE (Commission Internationale de l'Eclairage) which is going to replace R_a with a new color rendering index.

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LED is attracted attention as “New Generation Lighting Source”. In this report, the trend of LED lighting fixture's performance and the technology which is improved its problem are introduced. The main characteristic of LED lighting is “long life” and “saving energy (high efficiency)”. Efficiency of LED lighting fixture is decreased from that of LED package because of heat and some causes. Heat radiation from LED package and control of light distribution are important to best performance. Aluminum or resin is used for print circuit board, and heat sink must be designed in limitation appropriately.

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The material systems, the various approaches of the LED's, and the new types of LED's are reviewed. Firstly, the high efficiency of LED is reviewed, and the most used one, (460nm LED+yellow phosphor), is discussed. Secondly, LED with up to 400nm is discussed. Thirdly, InGaN covers all visible spectrums and the white LED's using InGaN are reviewed. The light emission intensity of InGaN is changed with the substrate orientation, and the white LED of InGaN is built. The In-rich InGaN LED is grown, and the reddish color LED is obtained. The high efficiency LED with Cu heat sink is reviewed. And finally, the AC-LED with the heat generation and the sink at exactly the same place is reviewed.

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An active matrix driving organic light emitting diode (AM-OLED) have been used as small and middle size display for mobile phone since 2007. The material technologies have improved lifetime dramatically over the past few years, and are now installed to realize the lighting industry. In this paper, I will discribe the current market for these technologies in the view from each OLED panel company and discuss in relation to their impact on market growth.

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Laser displays are attractive because of their low electric power consumption and the wide range of colors that can be realized. Small etendue of laser sources are advantageous for downsizing display systems. Recently, because the reduction in costs of the laser can be attempted by the market expansion on laser displays, laser lighting applications have become also attractive. In this paper, technologies of laser displays and laser lightings using highly efficient lasers are reviewed. Also, their applications and future prospects are introduced.

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