Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Mechanism control by the control signal
Reexamination Certificate
1999-09-28
2002-10-01
Hindi, Nabil (Department: 2753)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Mechanism control by the control signal
C369S263100, C369S266000
Reexamination Certificate
active
06459668
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an exchangeable-type disk apparatus, such as CD-ROMs, DVDs, MOs and removable HDDs, and more particularly to a disk-type reproducing apparatus in which the influence of unbalanced vibration of a disk is reduced.
2. Description of the Related Art
Most software for computers has been distributed in the form of CD-ROMs, and in order to reduce the installation time for such CD-ROMs and to afford comfortably enjoying games and so on, it has been required to increase the data transfer speed. To achieve this, it is necessary to turn (spin) a disk at high speed. A major problem encountered in this case is an increase in vibrations due to unbalance of the disk. In order to reduce the vibrations, Japanese Patent Unexamined Publication No. 10-083622 has proposed a method in which support legs of a rotating system are made sufficiently flexible to set the resonance frequency of the support system to a lower level than an operating revolution frequency, and the apparatus is operated in such overcritical condition that a balancer mounted in the rotating system corrects unbalance of the disk.
In the above prior art technique, the balancer comprises a spherical body (ball), and such spherical body rolls in a groove provided at a center of rotation to correct the unbalance. However, when the disk spins at a speed near the resonance frequency of the rotating system, the ball unsteadily moves in the rolling groove to cause unstable vibrations, thus producing vibrations and noises, and furthermore there has been a problem that servo for a disk reading system does not work to make reading of information impossible.
It is an object of the invention to provide a disk apparatus which eliminates a phenomenon that servo is made out of control by unstable vibrations developed when a disk is spun at a speed near the resonance frequency of the rotation support system of the above unbalance correcting mechanism.
SUMMARY OF THE INVENTION
The above object of the invention can be attained by positioning a ball in a position of correction while once increasing revolutions of a disk above the resonance frequency of the rotation support system when the disk is started to spin, and thereafter decreasing the revolutions to execute actuation of the servo.
REFERENCES:
patent: 5623382 (1997-04-01), Moritan et al.
patent: 5844866 (1998-12-01), Fujimoto et al.
patent: 5926449 (1999-07-01), Hiok et al.
patent: 6314077 (2001-11-01), Shishido et al.
Hirata Tomoki
Ishikawa Takashi
Miki Hisahiro
Satou Yoshihiro
Tajima Hisanobu
Antonelli Terry Stout & Kraus LLP
Hindi Nabil
Hitachi , Ltd.
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