Patents by Inventor Yasumasa Kuroba

Yasumasa Kuroba has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6904010
    Abstract: A method of STW (servo track write) for improving the quality of the servo tracks by suppressing the misalignment of the write start position caused by the asynchronous continuous vibration of a disk drive is disclosed. The disk drive includes a spindle motor, a disk medium, a write/read head and a head moving mechanism for carrying out the sector servo operation. The STW method comprises the steps of detecting the continuous vibration asynchronous with the rotational frequency of the spindle motor, detecting the phase of the asynchronous continuous vibration detected, determining the write start sector of each servo track based on the detected phase of the asynchronous continuous vibration, determining the write start time of each servo track in accordance with the clock signal, and moving the head onto the servo track where the head positioning information is written, by the head moving mechanism and writing the information in the servo track based on the write start time.
    Type: Grant
    Filed: February 24, 2000
    Date of Patent: June 7, 2005
    Assignee: Fujitsu Limited
    Inventors: Yasumasa Kuroba, Tomoyoshi Yamada
  • Patent number: 6819519
    Abstract: This invention relates to a head position control method for a disk device that uses a disk medium whose tracks have been formatted externally, and a disk device that effectively uses the range of motion of an actuator. In a disk device that has a disk medium, a head, an actuator, a control circuit, there is a conversion mechanism that sets a data area in the writing range of the disk that corresponds to the range of motion of the actuator, and converts a logical address to a physical address in the data area. This invention makes it possible to set a storage capacity that makes maximum use of the range of motion of the actuator for any device, even when there is a position offset in the range of motion of the actuator.
    Type: Grant
    Filed: December 21, 2000
    Date of Patent: November 16, 2004
    Assignee: Fujitsu Limited
    Inventors: Kazuhiko Takaishi, Yasumasa Kuroba, Mitsuo Kamimura, Tomoyoshi Yamada
  • Patent number: 6477017
    Abstract: Each arm module includes plate-shaped arms which lie on top of each other. A head slider is supported by the extending end of each arm module and faces a data recording surface of a magnetic disk. An actuator drives each arm module. Each arm module has a structure in which the plate-shaped arms which lie on top of each other are integrated with each other.
    Type: Grant
    Filed: February 5, 1999
    Date of Patent: November 5, 2002
    Assignee: Fujitsu Limited
    Inventors: Toru Kohei, Yasumasa Kuroba
  • Publication number: 20010040771
    Abstract: Each arm module includes a plurality of plate-shaped arms which lie on top of each other. A head slider is supported by the extending end of each arm module and faces a data recording surface of a magnetic disk. An actuator drives each arm module. Each arm module has a structure in which the plurality of plate-shaped arms which lie on top of each other are integrated with each other.
    Type: Application
    Filed: February 5, 1999
    Publication date: November 15, 2001
    Applicant: Fujitsu Limited
    Inventors: TORU KOHEI, YASUMASA KUROBA
  • Publication number: 20010022702
    Abstract: This invention relates to head position control method for a disk device the uses a disk medium whose tracks have been formatted externally, and the disk device that effectively uses the range of motion of an actuator. In a disk device that has a disk medium (2), head (3), actuator (5), a control circuit (8), there is a conversion mechanism (31) that sets a data area in the writing range of the disk (2) that corresponds to the range of motion of the actuator, and converts a logical address to a physical address in the data area. This invention makes it possible to set a storage capacity that makes maximum use of the range of motion of the actuator for any device, even when there is position offset in the range of motion of the actuator.
    Type: Application
    Filed: December 21, 2000
    Publication date: September 20, 2001
    Applicant: FUJITSU LIMITED
    Inventors: Kazuhiko Takaishi, Yasumasa Kuroba, Mitsuo Kamimura, Tomoyoshi Yamada
  • Patent number: 6081990
    Abstract: A method for incorporating a disk medium into a magnetic disk drive, in which the rotation center of the disk medium when a servo track information is written onto the disk medium (STW) coincides with the rotation center thereof when the disk medium is incorporated into the disk apparatus. A reference marker is provided as a positioning reference on a part of the disk medium. The disk medium is incorporated into a STW apparatus so that STW is performed on the disk medium. The disk medium is also incorporated into the magnetic disk drive in such a manner that a distance from an axis of rotation center of the disk medium to the reference marker is the same as when the STW was performed onto the disk medium.
    Type: Grant
    Filed: February 13, 1997
    Date of Patent: July 4, 2000
    Assignee: Fujitsu Limited
    Inventors: Yasumasa Kuroba, Tomoyoshi Yamada, Toru Kohei, Shinji Koganezawa, Mitsuaki Yoshida, Hiroyuki Iwahara
  • Patent number: 6025973
    Abstract: A compact card type disk drive includes a housing (21) for accommodating a disk for storing data, a disk drive for rotating the disk, a head assembly for writing and reading data to and from the disk and an electronic circuit including at least an interface circuit (39), the latter three being accommodated in the housing. A connector (42) connected to the electronic circuit is fixed to the outside portion of the housing (21). The electronic circuit preferably contains a read/write circuit (36) and a control circuit (38). The housing (21) preferably includes a lower base (22) and an upper cover (23), and a printed circuit board (14) is disposed along the inner wall of either one, or both, of the base (22) and the cover (23). The outer dimension of the plane of the disk drive is preferably about 85.6 mm.times.54 mm, and typically, the outer thickness is 5 mm. Preferably, one connector (42) is disposed on either one of the minor sides of the housing (21).
    Type: Grant
    Filed: December 17, 1998
    Date of Patent: February 15, 2000
    Assignee: Fujitsu Limited
    Inventors: Yoshifumi Mizoshita, Tomoyoshi Yamada, Yasumasa Kuroba, Toru Kouhei, Takao Sugawara, Masaru Matsumoto, Hiroyuki Mase, Masao Tsunekewa, Shinji Koganezawa, Keiji Aruga
  • Patent number: 6016237
    Abstract: A compact card type disk a drive includes a housing (21) for accommodating a disk for storing data, a disk drive for rotating the disk, head assembly for writing and reading data to and from the disk and an electronic circuit including at least an interface circuit (39), the latter three being accommodated in the housing. A connector (42) connected to the electronic circuit is fixed to the outside portion of the housing (21). The electronic circuit preferably contains a read/write circuit (36) and a control circuit (38). The housing (21) preferably includes a lower base (22) and an upper cover (23), and a printed circuit board (14) is disposed along the inner wall of either one, or both, of the base (22) and the cover (23). The outer dimension of the plane of the disk drive is preferably about 85.6 mm.times.54 mm, and typically, the outer thickness is 5 mm. Preferably, one connector (42) is disposed on either one of the minor sides of the housing (21).
    Type: Grant
    Filed: August 25, 1998
    Date of Patent: January 18, 2000
    Assignee: Fujitsu Limited
    Inventors: Yoshifumi Mizoshita, Tomoyoshi Yamada, Yasumasa Kuroba, Toru Kouhei, Takao Sugawara, Masaru Matsumoto, Hiroyuki Mase, Masao Tsunekewa, Shinji Koganezawa, Keiji Aruga
  • Patent number: 5926347
    Abstract: A magnetic disk apparatus includes a magnetic disk accommodated for rotation in a housing, a spindle mechanism for driving the magnetic disk to rotate, a magnetic head for writing and reading out information onto and from the magnetic disk, a suspension for supporting the magnetic head thereon, an actuator for driving the suspension in order to move the magnetic head in a radial direction of the magnetic disk, and a retraction mechanism for retracting the magnetic head to a particular area on the magnetic disk when the spindle mechanism is rendered inoperative. The magnetic disk apparatus further includes a mechanism provided at a location above the magnetic disk in an opposing relationship to the particular area of the magnetic disk for pressing at least one of the magnetic head and the suspension against the magnetic disk. In lieu of the pressing mechanism, a displacement restriction member may be provided.
    Type: Grant
    Filed: September 2, 1997
    Date of Patent: July 20, 1999
    Assignee: Fujitsu Limited
    Inventors: Tohru Kouhei, Tomoyoshi Yamada, Yasumasa Kuroba
  • Patent number: 5880904
    Abstract: A compact card type disk drive includes a housing (21) for accommodating a disk for storing data, disk drive for rotating the disk, a head assembly for writing and reading data to and from the disk and an electronic circuit including at least an interface circuit (39), the latter three being accommodated in the housing. A connector (42) connected to the electronic circuit is fixed to the outside portion of the housing (21). The electronic circuit preferably contains a read/write circuit (36) and a control circuit (38). The housing (21) preferably includes a lower base (22) and an upper cover (23), and a printed circuit board (14) is disposed along the inner wall of either one, or both, of the base (22) and the cover (23). The outer dimension of the plane of the disk drive is preferably about 85.6 mm.times.54 mm, and typically, the outer thickness is 5 mm. Preferably, one connector (42) is disposed on either one of the minor sides of the housing (21).
    Type: Grant
    Filed: March 20, 1995
    Date of Patent: March 9, 1999
    Assignee: Fujitsu Limited
    Inventors: Yoshifumi Mizoshita, Tomoyoshi Yamada, Yasumasa Kuroba, Toru Kouhei, Takao Sugawara, Masaru Matsumoto, Hiroyuki Mase, Masao Tsunekawa, Shinji Koganezawa, Keiji Aruga
  • Patent number: 5764441
    Abstract: A rotary moving coil actuator in a disk drive selectively positions a read/write head with respect to disk medium. A carriage is pivotable about an axis and has a carriage arm for supporting the head. A pair of magnets, disposed in spaced relationship within a magnetic yoke structure, have spaced flat faces perpendicular to the axis and define a gap therebetween. A flat coil structure, comprising one or a pair of flat coils, is attached to the carriage and disposed at least in part within the gap between the opposing flat faces of the magnets so as to be movable along a stroke of movement relatively thereto. The flat coil structure in cooperation with the magnets, generates a driving force in a direction approximately parallel to a first line which is perpendicular to the axis and passes through the axis and toward the read/write head and thereby substantially perpendicular to the seek direction of the head.
    Type: Grant
    Filed: April 23, 1996
    Date of Patent: June 9, 1998
    Assignee: Fujitsu Limited
    Inventors: Keiji Aruga, Yasumasa Kuroba, Tomoyoshi Yamada
  • Patent number: 5608592
    Abstract: A retracting assembly produces a constant torque, in a data zone of a magnetic disk, which is greater than static friction of a bearing for a rotary actuator. However, in a parking zone on an outer portion of the magnetic disk, the retracting assembly generates a torque which suddenly increases so that a large holding torque is obtained and a magnetic head is reliably locked.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: March 4, 1997
    Assignee: Fujitsu Limited
    Inventors: Yoshifumi Mizoshita, Tomoyoshi Yamada, Yasumasa Kuroba, Toru Kouhei, Takao Sugawara, Masaru Matsumoto, Hiroyuki Mase, Masao Tsunekewa, Shinji Koganezawa, Keiji Aruga