Sony Corporation

Fumiharu Sudo

Mitsuhiro Ueno

Hiroshi Ikuta

Yuji Shishido

Toru Nakahara

Shuichi Kikuchi

Yasuaki Kano

Hidetoshi Honda

Katsumi Maekawa

Takashi Mochida

Hisato Hirasaka

Takaaki Sanpei

Shigeo Kobayashi

Toshiaki Wakita

Kentaro Soeda

A magnetic tape cartridge includes a cartridge case, a pair of cylindrical hubs rotatably provided in the cartridge case, and a magnetic tape laid between the hubs and wound around outer peripheries of the hubs. Each of the hubs has an inner diameter portion provided with a height-position determining member. The height-position determining member determines a height position of the hub in the magnetic tape cartridge by contacting a driving shaft inserted in the hub when the magnetic tape cartridge is mounted in a magnetic recording and reproducing apparatus.

Position determining member to align a magnetic tape cartridge in a magnetic recording and reproducing apparatus

A magnetic head mounted on a rotary head drum device comprises a head chip, and a magnetic shield disposed to surround all or a part of the surfaces other than a front surface of the head chip. The magnetic shield comprises a magnetic flux absorber made of ferrite and an electromagnetic wave shield made of copper. This enables a reduction of the amount of unnecessary magnetic fluxes and electromagnetic waves jumping away from the recording head to the reproducing head. Simultaneously, the magnetic flux absorber absorbs the magnetic flux coming from outside to the reproducing head before the magnetic flux reaches the head chip and the electromagnetic wave shield shields a high frequency electromagnetic wave which was not absorbed by the magnetic flux absorberthat it is possible to reduce the amount of the magnetic flux or the like jumping into the reproducing head and to improve the S/N of the reproduced signal.

Magnetic head and rotary head drum device

Disclosed is a disk rotating mechanism equipped with an automatic aligning mechanism in which the number of parts is reduced and in which an improvement in assembly operability and a reduction in cost are achieved. The automatic aligning mechanism includes a case body made of a non-magnetic material and formed as a flat cylinder with one end surface closed, two or more balance members provided so as to be freely movable in the inner space (movement space) of the case body, and an attracting magnet adapted to attract the balance members when the rotating mechanism is at rest or rotating at low speed, wherein the case body is supported by the spindle shaft of a spindle motor and wherein the closed end surface (table portion) thereof serves as the table portion of a turntable.

Disk rotating mechanism

A rotation control device capable of suppressing vibrations of a rotation unit produced due to changes in weight unbalances of the rotation unit. On a disc rotation control device 2, made up of a driving shaft 8 rotated along with an optical disc 90, a turntable 9, a motor rotor 10 and a magnet 15 mounted on the motor rotor 10, balancer members 6, 7 are mounted so that the balancer members 6, 7 are rotatably supported on the driving shaft 8. The disc rotation control device 2 causes rotation of the rotation unit such that a synthesized center of gravity of the rotation unit offset from the center of rotation by the unbalances of the optical disc 90 and the balancer members 6, 7 will coincide with the center of rotation.

Rotation control apparatus

A magnet is provided which holds spherical balancers in the central portion of a rotor when the rotation of the rotor is stopped. When rotations of the rotor is started, a larger torque T.sub.0 is transmitted from the rotor to the balancers. Thus, the balancers quickly start rotating. When the rotor rotates at high speed, the centrifugal force separates the balancers from the magnet and moves the same to the outer wall portion of the rotor. At this time, a torque T.sub.0 which is transmitted from the rotor to the balancer is reduced so that the balancers are moved in the circumferential direction. Thus, the automatic aligning operation is performed. The number (n) of the balancers is made to be a value obtained by the following equation:

Rotation drive apparatus

Growing community of inventors

Tokyo, Japan

Fumiharu Sudo