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FUJI ELECTRIC JOURNAL 2002 Vol.75-No.3
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Magnetic Hard Disks / Photoconductors |
Present Status and Prospects for Magnetic Hard Disks
Nobuyuki Takahashi, Akihiro Otsuki, Tomonobu Ogasawara
Hard disk drives have been realizing more reduction in bit cost keeping a continuous high-rate increase in recording density, and it is now expected that they will be applied to consumer electronics as well as computers. This paper describes Fuji Electric's magnetic hard disks as a key technology to support this development. It summarizes the present technical status and targets for magnetic properties and head-disk interface properties required for advanced hard disk drive as well as future technical problems. Further, Fuji Electric's activities on new technologies to widen future applications are briefly introduced.
Magnetic Layers for Longitudinal Magnetic Recording Media
Yoshiharu Kashiwakura, Souta Matsuo, Yoshifumi Ajishi
This paper describes present magnetic layer technology for longi -tudinal magnetic recording media. Regarding the layer structure, the multicomponent alloy applied to magnetic recording layers and the multi-layered structure have enabled an incr ease in recording density. It is indispensable for future magnetic layers technology those aims at 30 Gbits/in2 or more to make read/write performance compatible with ther mal stability. New magnetic recording media utilizing antifer romagnetic coupling are regarded as a promising measure. Film formation and substrate surface processing technologies are as important as layer structure. Fuji Electric is now developing magnetic layer technology aiming at 100 Gbits/in2 as well as advancing these technologies.
Development in Head-Disk Interface Technology
Masaki Miyazato, Naruhisa Nagata, Hirofumi Kumazaki
Reduction in magnetic spacing is necessary to realize high recording density. This paper describes the present status of the chemical vapor deposition (CVD) and filtered cathodic arc (FCA) methods as thin film technologies for carbon protective layers. It explains the principles of deposition by each method, the superior Co corrosion properties in thinner region by the CVD method and the physical properties of films by the FCA method. Further, it refers to improvements in lubricant behavior and head flyability that are key points for attaining suitable hard-disk interface quality for low flying height.
Development of Glass Magnetic Hard Disks
Katsuya Masuda, Toyoji Ataka, Satoru Nakamura
Glass magnetic disk media are indispensable for the hard-disk drives of mobile personal computers, mobile audio-visual displays, and high-speed servers. The mainstream of glass magnetic disk media is isotropic media; however, the isotropic media is said to nearly reach the limit in parametric performance in case of higher recording density in the future. Fuji Electric is putting to practical use the technical and process developments capable of forming oriented media, which are rated superior in parametric performance, onto glass substrates at a low price. This paper describes the situation of this development.
Magnetic Layers for Perpendicular Recording Media
Hiroyuki Uwazumi, Yasushi Sakai, Shunji Takenoiri
Demand for hard disk drives is supposed to continue rapid expansion as storage devices especially for audio-visual use, and increase in capacity is strongly desired. Fuji Electric is promoting research and development to realize perpendicular recording media capable of ultra -high- density recording over 300 Gbits/in2. This paper describes control technology for the magnetic domain structure of soft magnetic back-layers that cause media noise and media evaluation technology using magnetic force microscopy, and also the developments of magnetic recording layer materials suitable for ultrahigh-density recording using a CoCrPt-SiO2 granular film and an amorphous film.
Magnetic Printing Technology
Kiminori Sato, Kazuo Nimura, Akira Saito
This paper introduces a novel magnetic printing technology as a promising alter native to the conventional servo-track writer required to write servo patterns onto hard-disk media. This technology is such that lithographically formed fine patterns (as servo patterns) of soft magnetic material on the surface of a master disk are transferred as magnetization patterns onto the media. The media with the servo patterns printed has been put into commercial production since July of 2001. The potential performance of the magnetic printing technology for the media of 200-300 Gbits/in2 is examined.
Present Status and Prospects for Photoconductors
Haruo Kawakami, Mitsuru Narita, Tatsuo Tanaka
This paper describes the market trends of printers and copy machines using Carlson's process. The shipment of printers has grown only by a few percent a year in recent years; however, the one of color printers has shown a rapid growth. Especially high- and medium-speed machines over 15 pages/min would be one of major streams in near future. Also printer on demand is expected to form a new printer market. Regarding copy machine, the shipment of digital machines has shown a steady growth and the replacement of analog machines is going on.
Organic Photoconductors for Printers
Seishi Terasaki, Koji Fukushima, Masahiro Morimoto
Among electrophotographic printers such as laser-beam printers and light-emitting-diode (LED) printers, high-speed machines, multi-functional machines with facsimile and copying functions, and full-color printers are supposed to diffuse. Accordingly, performance and qualityrequired by photoconductors, the major component, are becoming more sophisticated. Fuji Electric is developing and manufacturing various photoconductors to meet these requirements. This paper particularly describes an outline of negatively charged organic photoconductors for printers as well as their features.
Organic Photoconductors for Digital Plain Paper Copiers
Micho Shinozaki, Masahiko Kasahara, Shuichi Hamada
The copier market is rapidly shifting from analog machines to digital ones in line with the recent trend of digitization. Because there are printers as competitors in the fields of low and medium speed, digital copiers show a tendency toward high-speed machines. To increase operation speed, organic photoconductors are required to have high sensitivity and high durability. To meet these market requirements, Fuji Electric has developed high-performance types and prepared a wide range of products compatible with low-, medium- to high-speed machines. This paper describes organic photoconductors for digital copiers, focusing on the high-sensitivity type (type 10C).
Positively Charged Organic Photoconductors
Shinichi Omokawa, Hideyuki Ishii, Osamu Nabeta
Fuji Electric, having produced single-layer, positively charged organic photoconductors for conventional low- and medium-speed printers, has developed a new type single-layer, positively charged organic photoconductor (type 11D) with high sensitivity and durability. Since the type 11D has short response time, and also, superior properties in environmental stability, stability in repeated operation, resolution, and durability. Its application to high-speed printing can be expected.
Photoconductor Evaluation Technology (A Study of 1-dot Latent Image Potential)
Kouichi Aizawa, Yoshihiro Ueno, Motohiro Takeshima
In order to make high-resolution electrophotographic images, it is useful to evaluate 1-dot latent image potential formed on the photocon -ductor. This paper describes a new method of measuring micro-area surface potential profiles and analyzing the latent image potential. The evaluation results of the 1-dot latent image potential of negatively charged double-layer organic photoconductors and positively charged single-layer organic photoconductors are presented. The dependence of the latent image on film thickness and charge mobility is also exam -ined.
Process Units for Electrophotographic Machine
Seizo Kitagawa, Tadashi Asakawa, Yoshihiko Tanaka
The trend in the market of electrophotographic machines such as copy machines, fax equipment, and printers is pointing toward compact, low-priced, digital, multi-functional, and color units. The electrophotographic processes in these products ar e unitized to minimize maintenance. Fuji Electric is manufacturing not only photoconductor drums but also process units by utilizing process technologies achieved during the development of photoconductor drums. This paper outlines the configuration, types, features, and market trend of the units and Fuji Electric's activities. In addition, the development of positively charged process units that have particularly high potential in the above-mentioned trend is introduced.
