The networking of information output devices such as printers and copiers is rapidly advancing and there is a strong demand for compact, energy-efficient devices. It is important that the heart of these devices, the photoconductors, have high functionality for greater longevity and reduction of waste toner. As a producer of photoconductors, Fuji Electric has contributed to the expansion of the market for information output devices. In regard to organic photoconductors for printers and organic photoconductors for plain paper copiers, this paper presents various technologies for the evaluation of photoconductors and technologies for development of organic materials, with a focus on technologies for high sensitivity, high resolution, and high durability.

In the field of electrophotographic devices as information output devices, technical development toward colorization, high resolution, and high durability is advancing. Fuji Electric is developing technologies including higher resolution and lower toner consumption of organic photoconductors for printers (type 8) as well as higher durability of photoconductors for plain paper copiers (type 10). Higher resolution mechanism of positive charged OPC (type 11), which can reduce the　environment　load, has been clarified by using latent image evaluation technology. Moreover, the approach to develop higher sensitivity and high response materials is progressing for more sensitive positive charged OPC (type 12). In addition, we are attempting to speed up the development of photoconductive materials through advancing the molecular simulation and materials evaluation technology.

Fuji Electric provides customers with organic photoconductors (OPCs) to meet demands for higher sensitivity and stability in imageforming function, and to reduce power consumption, the amount of raw materials and overall environmental impacts in the product lifecycle. In organic photoconductors development, it is essential to develop materials that can meet the various performance requirements such as functional materials, polymer materials, additives, etc., and we are advancing the development of optimal materials using our own molecular design technology and chemical synthesis technology. Some recent examples of our development include crack-resistance against petroleum solvent, and improved electric potential stability in hot environments, as well as optimal hole transport materials and film-forming materials optimized for positively charged photoreceptors.

To match the advancement of information processing, electrophotographic printers are expected to meet numerous demands for sophistication, high definition, cost reduction, energy efficiency, and so on. Moreover, consumers want equipment that can satisfy these demands whilst also being compact and maintenance-free. To meet such demands, Fuji Electric is developing, manufacturing, and marketing a rich lineup of photoconductors. For example, photoconductors for negative-charge type printers are capable of meeting a wide range of requirements, such as sensitivity region, printing speed, and service life; and as for organic photoconductors (OPCs) for positive-charge type printers, in addition to single-layer type photoconductors with low or medium sensitivity, we are expanding the market to include multi-layer type OPCs with higher sensitivity.

By improving the durability of organic photoconductors (OPCs), Fuji Electric aims to reduce waste and running costs and contribute to preservation of the environment. In order to achieve high product durability, high electrostatic propensity, and high printing durability are especially important. As for improving electrostatic propensity, in addition to the selection of materials that demonstrate optimal resistivity in the undercoat layer (UCL) and optimization of material blend ratios, by pursuing the optimization of the ionizing potential of the charge generation layer (CGL) and charge transport layer (CTL), we have increased performance. Our development of a highly durable CTL resin is facilitated by computer-based molecular structure design.

In order to improve the printing quality of electrophotography devices, it is important to improve the reproducibility of the electrical latent image formed on the photoconductor after charging and exposure. The results of latent image measurements using a micro area surfacepotential probe (MASPP) and an electrostatic force microscope (EFM) (developed to clarify the electrical latent image structure on the photoconductor)have demonstrated that low-mobility photoconductors, having low charge mobility, obtain more detailed latent image electrical potential. We clarified that expansion of latent image width is caused by anisotropy of charge mobility. A photoconductor with high mobility and high resolution requires choosing the materials in which the anisotropy of charge mobility occurs by regulating cohesion and orientation in the dipping layer, or by interacting with the resin.

While the market for solar cells continues to expand, there is a trend of excess in supply, and prices continue to decrease. Fuji Electric has developed and opened the market for light, flexible, amorphous silicon solar cells utilizing plastic film materials as the substrate. As a new development, Fuji Electric is also pioneering new markets in the field of function-added power generation, which combines film substrate solar cells and functional materials, and the field of low voltage power, which includes portable power sources and consumer use. Including these new initiatives, this paper presents our solar cells and their applied technologies, as well as film substrate solar cell modules and examples of their application.

Global market of solar energy generation remains strong due to prevalence measures in Japan, US and China. Fuji Electric has launched flexible amorphous silicon solar cells “FWAVE” in the market, and expanded the market by exploiting new field such as consumer use. Steel plate integrated solar cell module is light and enabled to install on aesthetical design roof by using its light and flexible fitting property to curved surface. Film substrate solar cell modules can easily apply to various products such as sheet module for portable power source, and simple install type module for agricultural and fishery use by exploiting the feature possible to reconfigure to a low voltage module.

In order to develop a new market for film substrate solar cells, Fuji Electric has commenced sale in cell structure. Because our film substrate solar cells use an original series-connection structure, they can be freely divided into several solar cell units. Utilizing this feature, we can design not only the size but also the output voltage within a wide range, from several volts to several hundred volts. Also, as our solarcells are made with a thermal-resistant polyimide film, they are lightweight and highly flexible. Making good use of these features, we are developing a variety of unique products, such as mobile solar units, solar bags and roll screen curtains in collaboration with our customers.

Fuji Electric has developed a flexible solar cell module that utilizes the characteristics of film substrate solar cells, being lightweight, flexible and not easily broken. To enable a wide range of applications of this flexible module, we have incorporated it as a base in developing various other modules, such as a steel-plate-integrated module, a waterproof-sheet-integrated module and a lightweight module. In recent years, with the increasing popularization of solar cells, there has been a higher demand for safety and reliability, and the acquisition of JET certification is gradually becoming an essential requirement. Through the conduct of preliminary experiments in adjusting module materials and thickness, we were able to develop a module structure that passed the approval fire test and obtained JET certification.

To increase the efficiency of film substrate solar cells, Fuji Electric is developing microcrystalline silicon (μc-Si) solar cells. It is essential to increase the deposition rate of the μc-Si solar cells. Despite the trade-off relation between the deposition rate and the efficiency, we have succeeded to obtain high efficiency equal to or higher than in the initial stage of development while the deposition rate quadrupled by improving deposition methods and conditions. Applying these techniques to multi-junction solar cells, we have attained a high level stabilizing efficiency of 11.7 %, being higher than that of the present solar cells on film substrates.

The memory capacity of hard disk drives (HDDs) is increasing at a rate of over 40% a year. Furthermore, demand for data centers is increasing, with the anticipated annual market growth rate of over 8%. Through its efforts to develop and mass-produce the latest magnetic recording media as quickly as possible, Fuji Electric has contributed to capacity enlargement of recording media. This paper presents the direction of technology and the current state of development for the latest high-performance technology with 500 GB per 2.5 inch disk, as well as the next generation technologies such as shingled-write recording and thermal-assisted magnetic recording media that will support this capacity enlargement beyond 1 TB.

It is expected that market of hard disk drives (HDDs) will continue to increase and will grow stably until 2020. Although the recording density of HDD has attained 1TB per 3.5 inches disk, the technology break-through such as applying shingled write recording, or thermal assisted magnetic recording is needed for realizing further high capacity. In order to realize these new technologies, Fuji Electric is dedicating to develop individual technologies toward higher recording capacity including substrate, magnetic layer relating, head-disk interface (HDI) and next generation magnetic recording technologies.

Fuji Electric is researching the reduction of the magnetic spacing between the magnetic head and the soft magnetic under-layer, as one of the methods to overcome the problem of trilemma, to increase the recording density of perpendicular magnetic recording media. Conventionally, non-magnetic interlayers have been designed with functions divided into two, but by employing a three-way functional separation design, we were able to make non-magnetic interlayers thinner to reduce the magnetic spacing. We applied a new material as a grain size control layer, improved the composition of the collateral crystalline layer based on results of basic research, and addition of a magnetic anisotropy-enhancing layer as a new functional layer. As a result, we were able to ensure ease of recording, increase both signal quality and thermal stability, and successfully break the bottleneck of trilemma in magnetic recording.

To increase the recording density of perpendicular magnetic recording media, it is necessary to reduce the distance between a write element and a magnetic recording layer, or a magnetic spacing. For that purpose, we are conducting research to control the process for depositionof the protective layer and reduce the thickness of the protective layer, while also improving corrosion resistance and durability. We are also making efforts to reduce the thickness of the lubricant film through investigation into the molecular structure and molecular weight of the lubricant substance, and to improve both head fly-ability and wear resistance through investigation into the additives used. Additionally, we are developing evaluation technology to look into the phenomena that occur in a low-flying head disk interface (HDI), and we are making efforts to increase the recording density and ensure a high level of reliability for perpendicular magnetic recording media.

We are developing media-design technology, material technology and evaluation technology for thermal-assisted magnetic recording media. In media design, we have established new methods of thermal diffusion design through simulations. These have enabled us to design a medium-layer structure for efficient heating and cooling. We verified the validity of our planned method by confirming the heat-conducting superiority of the planned medium-layer structure using the actual medium. Also, in our development of materials, we have created high anisotropy constant materials and have also established an evaluation system that can estimate remanent coercivity of thermal-assisted magnetic recording media over a few nanoseconds.