Fuji Photo Film Company, Limited

Fjui Photo Film Co., Ltd.

Tsutomu Sugisaki

Takahito Miyoshi

Yasutoshi Okuzawa

Minoru Kanazawa

Takuzi Yamada

Naoyoshi Chino

Tadashi Irie

Kazutoshi Machida

Yasuyuki Yamada

Kiyomi Ejiri

Tatsuji Kitamoto

Akihiro Matsufuji

Akira Kasuga

Yasushi Endo

Chiaki Mizuno

Kenichi Masuyama

Hideomi Watanabe

Yasuhiro Noguchi

Minoru Sueki

Hajime Miyatuka

Hisatake Ono

Masaya Kojima

Fumiaki Tsukuda

A magnetic recording medium comprising two or more magnetic layers provided on a support, wherein an easily magnetizable axis of an uppermost magnetic layer and an easily magnetizable axis of a lower magnetic layer are oriented in directions crossing each other at right angles, which can attain both a highly precise servo write and a higher recording density.

Magnetic recording medium and signal recording system comprising at least two magnetic layers with orthogonally oriented axes

Information is recorded on a floppy disk in a state in which the confidentiality of the information is maintained. An ID signal representing ID information is magnetically recorded down to the lower layer of a floppy disk when data is recorded. A data signal representing information (a data file) to be recorded is also magnetically recorded down to the lower layer of the floppy disk. A security signal is magnetically recorded on the upper layer of the floppy disk over at least the data signal that has been recorded on the lower layer of the floppy disk. At the time of data reproduction, the ID signal is reproduced from the floppy disk and the ID information represented by the reproduced ID signal is compared with entered ID information. When the two items of compared ID information agree, the security signal that has been recorded on the upper layer of the floppy disk is erased. The data signal that has been recorded on the lower layer of the floppy disk is then reproduced.

Magnetic recording/reproducing method

In a magnetic recording medium comprising a nonmagnetic substrate, a first magnetic layer, and a second magnetic layer mounted in this order, the first magnetic layer has a greater coercive force and a lower residual flux density than the second magnetic layer. When the second magnetic layer is directly mounted on the first magnetic layer, the second magnetic layer has a thickness within the range of 0.05-0.5 .mu.m and a coercive force within the range of 1200-2000 Oe while the first magnetic layer has a coercive force greater than that of the second magnetic layer by 800-2500 Oe and a residual flux density in the range of 30-70% of that of the second magnetic layer. When a nonmagnetic layer is held between the first and second magnetic layers, the first magnetic layer has a coercive force not smaller than 2000 Oe and a residual flux density not greater than 70% of that of the second magnetic layer while the second magnetic layer has a coercive force not smaller than 1200 Oe, a residual flux density not lower than 1600 G, and a thickness not greater than 0.5 .mu.m.

Magnetic recording medium

A cartridge including a cartridge case having a disc-shaped recording medium received therein so as to allow predetermined information signals to be recorded and reproduced, and a shutter and method for producing the shutter which is molded of a synthetic resin to slidably open and close an opening portion formed on the cartridge case so as to allow at least a part of the disc-shaped recording medium to be exposed to the outside. The shutter includes an upper main plate, a lower main plate and a coupling plate which connects the upper main plate to the lower main plate via the coupling plate in an integrally molded state while having a U-shaped cross-sectional contour to hold the cartridge case in a clamped state. A gate used for performing a molding operation is formed on the outer surface of the side plate, with the position of the gate being determined such that it always remains within an effective opening region corresponding to the opening portion.

Method for producing shutter for disc cartridge

A cartridge including a cartridge case having a disc-shaped recording medium received therein so as to allow predetermined information signals to be recorded and reproduced, and a shutter molded of a synthetic resin to slidably open and close an opening portion formed on the cartridge case so as to allow at least a part of the disc-shaped recording medium to be exposed to the outside. In accordance with the present invention, the shutter is composed of an upper main plate, a lower main plate and a coupling plate which connects the upper main plate to the lower main plate via the coupling plate in an integrally molded state while having an U-shaped cross-sectional contour to hold the cartridge case in a clamped state. A gate used for performing a molding operation is formed on the outer surface of the side plate, with the position of the gate being determined such that it always remains within an effective opening region corresponding to the opening portion. The invention also provides a method for producing the shutter.

Synthetic resin disc cartridge shutter having non-engaging raised gate

A magnetic tape cassette having a guide pole which is in sliding contact with the magnetic surface of the tape produced in such a manner as to improve the running characteristics of the tape while being capable of being manufactured at a low cost. A cylindrical stainless steel base member is subjected to a barreling treatment so as to secure fine particles of an inorganic material having a Moh's hardness of greater than 9 to the slide surface of the guide post. Moreover, the surface of the guide pole can be finished by a surface rolling to reduce the number of scratch-like grooves in the slide surface having a depth of more than 0.2 .mu.m and a width of less than 40 .mu.m to less than 11 per millimeter in the sliding direction of the tape.

Magnetic tape cassette having improved guide pole structure

A magnetic recording medium is disclosed. The medium is comprised of a support having a magnetic layer coated thereon. The magnetic layer is comprised of a ferromagnetic metal powder and a binder. The ferromagnetic metal powder has a specific surface area of not less than 30 m.sup.2 /g. The magnetic layer is further comprised of a fatty acid and a fatty acid ester in a total amount of 2 to 10 wt % based on the weight of the ferromagnetic metal powder. The proportion of the fatty acid ester is 15 to 60 wt % based on the total weight of the fatty acid and the fatty acid ester. The surface roughness of the magnetic layer is not more than 0.03.mu.. The recording medium has excellent video characteristics obtained by the use of fine metal particles having the disclosed specific surface area and by increasing the surface properties of the magnetic layer so that spacing loss between the recording or reproducing head and the recording tape is decreased and output level is increased and modulation noise is decreased so that the video S/N is increased.

A cleaning jacket for a magnetic head used for flexible discs comprising a cleaning sheet and a sheet retaining jacket, the cleaning sheet comprising a flexible and non-magnetizable support, at least on one surface of which is provided an antistatic layer and on the other surface of which is provided a cleaning layer of a fibrous material, the retaining jacket having the shape of a flat casing and defining a space in which the cleaning sheet can be kept in such a manner that it can rotate freely therein, and, further, having a lubricating layer provided on the inner wall thereof facing the antistatic layer of the cleaning sheet.

Magnetic head cleaning jacket

A cartridge for cleaning a magnetic head for use with flexible discs. The cartridge contains a cleaning disc comprising a flexible and non-magnetic support, with a magnetic layer provided on one or both surfaces of the flexible and non-magnetic support. A fibrous material layer is provided on one layer of the magnetic layers where both surfaces of the cleaning disc carry a magnetic layer or on the surface free of a magnetic layer when only one surface carries a magnetic layer. The flat box-like cartridge has a lubricating layer provided on the inner surface thereof which faces the exposed magnetic layer of the cleaning disc, and is capable of rotatably accomodating the cleaning disc.

Cleaning cartridge

An information display method comprising forming an image of a chemiluminescent component on a support according to information to be recorded and placing the support bearing the image of the material in an atmosphere capable of effecting the chemiluminescence of the material to thereby display the image based on a difference in luminance.

Growing community of inventors

Kanagawa, Japan

Tsutomu Sugisaki