Patents by Inventor Takao Furuhashi
Takao Furuhashi 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).
-
Publication number: 20240096362Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including a write head which writes data to the magnetic disk, a read head which reads data from the magnetic disk, a first heater which adjusts a flying height of the write head, a second heater which adjusts a flying height of the read head and a controller which controls powers supplied to the first heater and the second heat, and controls a power value of the power supplied to the first heater according to a ratio between an electric resistance value of the first heater and an electric resistance value of the second heater.Type: ApplicationFiled: March 9, 2023Publication date: March 21, 2024Inventor: Takao FURUHASHI
-
Patent number: 11335374Abstract: According to one embodiment, a magnetic disk device includes a disk having a first sector including first servo data, first user data, and first correction information used to correct a data error, a head that writes data to the disk and that reads data from the disk, and a controller that changes, according to a first defect length of a defect generated in the first sector in a circumferential direction of the disk, a first sector length of the first sector in the circumferential direction.Type: GrantFiled: February 19, 2021Date of Patent: May 17, 2022Assignees: KABUSHIKI KAISHA TOSHIBA, TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATIONInventors: Kazumi Fujimoto, Takao Furuhashi
-
Publication number: 20220068307Abstract: According to one embodiment, a magnetic disk device includes a disk having a first sector including first servo data, first user data, and first correction information used to correct a data error, a head that writes data to the disk and that reads data from the disk, and a controller that changes, according to a first defect length of a defect generated in the first sector in a circumferential direction of the disk, a first sector length of the first sector in the circumferential direction.Type: ApplicationFiled: February 19, 2021Publication date: March 3, 2022Inventors: Kazumi Fujimoto, Takao Furuhashi
-
Patent number: 11074936Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including a read head to read data from the magnetic disk and a write head to write data to the magnetic disk, and a controller configured to control read/write from/to the magnetic disk by the magnetic head. The magnetic head includes a thermal actuator configured to project a head surface of the magnetic head to a recording surface of the magnetic disk, and a detector configured to detect a gap between the head surface and the recording surface of the magnetic disk. The controller controls a degree of projection of the magnetic head to the recording surface by the thermal actuator corresponding to the gap detected by the detector during the read/write.Type: GrantFiled: July 27, 2020Date of Patent: July 27, 2021Assignees: Kabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage CorporationInventors: Toru Watanabe, Takao Furuhashi, Akihiro Yamazaki
-
Publication number: 20210193178Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including a read head to read data from the magnetic disk and a write head to write data to the magnetic disk, and a controller configured to control read/write from/to the magnetic disk by the magnetic head. The magnetic head includes a thermal actuator configured to project a head surface of the magnetic head to a recording surface of the magnetic disk, and a detector configured to detect a gap between the head surface and the recording surface of the magnetic disk. The controller controls a degree of projection of the magnetic head to the recording surface by the thermal actuator corresponding to the gap detected by the detector during the read/write.Type: ApplicationFiled: July 27, 2020Publication date: June 24, 2021Inventors: Toru Watanabe, Takao Furuhashi, Akihiro Yamazaki
-
Patent number: 10847182Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk section and a control section. The magnetic disk section includes a magnetic disk, a magnetic head, and a preamplifier. The control section included a processing section configured to cause the preamplifier to execute processing of generating the recording current used by a write head to write data to the magnetic disk, and processing of receiving an output reproduced from the magnetic disk by a read head, and configured to control the magnetic disk section. In the preamplifier, processing of reading data from the magnetic disk is executed by the read head in parallel with processing of writing data transferred from the control section to the magnetic disk by means of the write head.Type: GrantFiled: September 11, 2019Date of Patent: November 24, 2020Assignees: Kabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage CorporationInventor: Takao Furuhashi
-
Publication number: 20200302967Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk section and a control section. The magnetic disk section includes a magnetic disk, a magnetic head, and a preamplifier. The control section included a processing section configured to cause the preamplifier to execute processing of generating the recording current used by a write head to write data to the magnetic disk, and processing of receiving an output reproduced from the magnetic disk by a read head, and configured to control the magnetic disk section. In the preamplifier, processing of reading data from the magnetic disk is executed by the read head in parallel with processing of writing data transferred from the control section to the magnetic disk by means of the write head.Type: ApplicationFiled: September 11, 2019Publication date: September 24, 2020Inventor: Takao Furuhashi
-
Patent number: 10020017Abstract: According to one embodiment, a hard disk drive includes a disk including a plurality of data areas, and a plurality of servo areas between the plurality of data areas, an arm holding a write head and a read arm, and a positioning module which positions the read head or the write head by rotating the arm, wherein the positioning module positioning the write head by positioning the read head, and adjusting a position of the read head or the write head, based on an output of the read head located in a data area between two servo areas adjacent in a peripheral direction, of the plurality of servo areas.Type: GrantFiled: December 18, 2015Date of Patent: July 10, 2018Assignee: Kabushiki Kaisha ToshibaInventor: Takao Furuhashi
-
Publication number: 20170061997Abstract: According to one embodiment, a hard disk drive includes a disk including a plurality of data areas, and a plurality of servo areas between the plurality of data areas, an arm holding a write head and a read arm, and a positioning module which positions the read head or the write head by rotating the arm, wherein the positioning module positioning the write head by positioning the read head, and adjusting a position of the read head or the write head, based on an output of the read head located in a data area between two servo areas adjacent in a peripheral direction, of the plurality of servo areas.Type: ApplicationFiled: December 18, 2015Publication date: March 2, 2017Inventor: Takao Furuhashi
-
Patent number: 7706091Abstract: The present invention relates to a magnetic disk device and provides a magnetic disk device in which data recording areas are separately set based on the inner recording boundary or outer recording boundary of the head measured for each magnetic disk device. When the recording linear (angular) density that has to be attained to ensure a prescribed capacity cannot be attained by the head, the recording linear (angular) density that has to be attained by the head is reduced and the prescribed capacity is realized by expanding the data recording area. A method using a counter-electromotive force generated when the head is moved toward a stopper or ramp load or a method by which the measurements are conducted based on the head position information from the servo signal can be used for measuring the positions of the inner recording boundary and outer recording boundary of the head.Type: GrantFiled: February 22, 2007Date of Patent: April 27, 2010Assignee: Toshiba Storage Device CorporationInventors: Takao Furuhashi, Kazuhide Ohba, Yoshimichi Sakai
-
Patent number: 7317587Abstract: The present invention relates to a magnetic disk device and provides a magnetic disk device in which data recording areas are separately set based on the inner recording boundary or outer recording boundary of the head measured for each magnetic disk device. When the recording linear (angular) density that has to be attained to ensure a prescribed capacity cannot be attained by the head, the recording linear (angular) density that has to be attained by the head is reduced and the prescribed capacity is realized by expanding the data recording area. A method using a counter-electromotive force generated when the head is moved toward a stopper or ramp load or a method by which the measurements are conducted based on the head position information from the servo signal can be used for measuring the positions of the inner recording boundary and outer recording boundary of the head.Type: GrantFiled: February 9, 2005Date of Patent: January 8, 2008Assignee: Fujitsu LimitedInventors: Takao Furuhashi, Kazuhide Ohba, Yoshimichi Sakai
-
Publication number: 20070171560Abstract: The present invention relates to a magnetic disk device and provides a magnetic disk device in which data recording areas are separately set based on the inner recording boundary or outer recording boundary of the head measured for each magnetic disk device. When the recording linear (angular) density that has to be attained to ensure a prescribed capacity cannot be attained by the head, the recording linear (angular) density that has to be attained by the head is reduced and the prescribed capacity is realized by expanding the data recording area. A method using a counter-electromotive force generated when the head is moved toward a stopper or ramp load or a method by which the measurements are conducted based on the head position information from the servo signal can be used for measuring the positions of the inner recording boundary and outer recording boundary of the head.Type: ApplicationFiled: February 22, 2007Publication date: July 26, 2007Inventors: Takao Furuhashi, Kazuhide Ohba, Yoshimichi Sakai
-
Publication number: 20050168861Abstract: A head is in general subjected to vibration at the completion of the seek operation due to the inertial force. The head is restrained from writing operation for a predetermined duration after the completion of the seek operation. The head is allowed to start the writing operation after the vibration has sufficiently converged in this manner. The loss of data can reliably be avoided in the adjacent recording track. Moreover, the duration is set unique to the individual head. The duration can be set for the individual heads with a higher accuracy. The duration can thus be reduced to the utmost for the individual heads. The duration of the writing operation can be shortened as compared with a conventional technique.Type: ApplicationFiled: July 29, 2004Publication date: August 4, 2005Inventor: Takao Furuhashi
-
Publication number: 20050134994Abstract: The present invention relates to a magnetic disk device and provides a magnetic disk device in which data recording areas are separately set based on the inner recording boundary or outer recording boundary of the head measured for each magnetic disk device. When the recording linear (angular) density that has to be attained to ensure a prescribed capacity cannot be attained by the head, the recording linear (angular) density that has to be attained by the head is reduced and the prescribed capacity is realized by expanding the data recording area. A method using a counter-electromotive force generated when the head is moved toward a stopper or ramp load or a method by which the measurements are conducted based on the head position information from the servo signal can be used for measuring the positions of the inner recording boundary and outer recording boundary of the head.Type: ApplicationFiled: February 9, 2005Publication date: June 23, 2005Inventors: Takao Furuhashi, Kazuhide Ohba, Yoshimichi Sakai