Hitachi Global Storage Technologies Netherlands B.v.

International Business Machines Corporation

Hitoshi Tamura

Hiroki Mori

Hiroshi Matsuda

Toshiki Hirano

Kazuo Sasaki

Takehiko Hamaguchi

Kenji Kuroki

Mutsuro Ohta

Hiroki Kitahori

Hiroaki Uchiyama

Keishi Takahashi

Masahiko Katoh

Mitsuru Kitamura

Satoshi Noguchi

Masashi Murayama

Tatsuo Hayakawa

Shigeki Watabe

Mitsuru Hamaguchi

Kunihiko Mine

Migifumi Ikeda

Embodiments in accordance with the present invention provide a degaussing device and a degaussing method capable of efficiently degaussing a magnetic disk, especially, a magnetic disk of the perpendicular magnetic recording system, without resorting to a magnetic field of a high intensity. Embodiments in accordance with the present invention provide a degaussing method of degaussing a magnetic disk not yet installed in a magnetic disk drive by applying an external magnetic field to the magnetic disk by a degaussing device. In accordance with one embodiment, the method includes disposing the magnetic disk in the degaussing device such that the direction of an external magnetic field is inclined at an angle to the axis of easy magnetization of the magnetic disk.

Magnetic disk degaussing device and degaussing method

Embodiments of the invention prevent a spindle motor from stopping rotation while data on a magnetic disk is being erased by using a permanent magnet. In one embodiment, data in the whole area of the magnetic disk is erased as a consequence of the magnetic disk rotating in the magnetic field of the permanent magnet located so as to face a part of the magnetic disk. A back yoke is located so as to face a base. The back yoke gives a magnetic force to the spindle motor in the opposite direction of the magnetic force of the erasing permanent magnet so that the fluid dynamic bearing spindle motor can retain the rotation as required without stopping rotation.

Data erasure apparatus and data erasure method

A magnetic circuit is provided in an enclosure that can efficiently generate magnetic flux from the enclosure, configuring a magnetic disk, to a magnetic disk. Thus, by providing such a magnetic circuit, a magnetic field different from that in other enclosure parts, that is, a local magnetic field, is generated from the magnetic circuit in case the disk device is set in an external magnetic field. Hence, this local magnetic field can effectively erase data in the magnetic disk. In particular, since the local magnetic field is generated even if the external magnetic field is weak, it is possible to not only suppress the demagnetization of permanent magnets used in the spindle motor at minimum, but also effectively erase data in the magnetic disk.

Disk device and data-erasing method

An apparatus and method for adjusting balance in a disk drive, and a method for assembling a disk drive, enables the modification of dynamic balance reliably and efficiently. The apparatus adjusts balance in a hard disk drive having disks and a spindle which are assembled in a base. The acceleration to be applied from an actuator is made to act on the top end of the spindle through a holder plate in one accelerator, while the acceleration to be applied from an actuator is made to act on the base end of the spindle through the base in another accelerator.

Apparatus and method for adjusting balance and assembling disk drives

The object of the present invention is to provide a method and apparatus configured to allow an externally generated magnetic field to simultaneously erase a portion of the information on a disk, or a plurality of disks, within a magnetic storage device. The invention allows high throughput of erased magnetic storage devices, as in a mass production environment. Additionally, the invention allows a variety of magnetic storage device configurations in that the erasing is non-intrusive to the housing of the magnetic storage device and does not depend on the number of disks within the magnetic storage device.

Method and apparatus for erasing information from a disk within a magnetic disk drive using an externally generated magnetic field

Growing community of inventors

Kanagawa, Japan

Hitoshi Tamura