Dynamic magnetic information storage or retrieval – General recording or reproducing – Specifics of biasing or erasing
Reexamination Certificate
1998-10-19
2001-03-20
Kim, W. Chris (Department: 2753)
Dynamic magnetic information storage or retrieval
General recording or reproducing
Specifics of biasing or erasing
C360S046000
Reexamination Certificate
active
06204983
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an apparatus of recording data on a magnetic disk, which is suitable for application to, for example, a large-capacity floppy disk drive or the like.
In a conventional floppy disk drive, when an erase head wide in gap is placed as previous to a read/write head and data is recorded on a floppy disk, a dc erase or an ac erase is performed by the erase head in advance and thereafter the data is recorded by the read/write head to thereby ensure a requested overwrite characteristic.
A floppy disk drive having large or mass capacities ranging from several tens of Mbytes to several hundred Mbytes has been proposed in recent years. In the large-capacity floppy disk drive, a recording density becomes high and a recording wavelength becomes short. Therefore, when an erase head is disposed as prior or previous to a read/write head, it is necessary to place the read/write head and the erase head in close proximity to each other. It is however very hard to place them close to each other in terms of a head structure. When the erase head is placed as previous to the read/write head, the entire head will increase in cost because the erase head is needed in addition to the read/write head.
It is therefore an object of the present invention to provide an apparatus of recording data on a magnetic disk, wherein a requested overwrite characteristic can be ensured by a single head alone and waveform distortion can be restrained from appearing.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention, a magnetic recording apparatus comprises a magnetic head for applying a magnetic field to a magnetic record medium to form a magnetized pattern on said magnetic record medium and thereby recording record data; conversion means for converting input data into the record data having a predetermined frequency range; and control means for controlling said magnetic head so as to apply a DC magnetic field to a record area of said magnetic record medium, to apply to said record area a magnetic field that is inverted at a constant period corresponding to an intermediate frequency within said predetermined frequency range, and to apply to said record area a magnetic field that is inverted in accordance with the record data, when said magnetic head records the record data on the record area.
According to a second aspect of the present invention, said magnetic record medium is a magnetic disk.
According to a third aspect of the present invention, said magnetic head records the information on said magnetic record medium under a condition that said magnetic head floats over said magnetic record medium.
In accordance with a fourth aspect of the present invention, a magnetic recording apparatus further comprises selection means for outputting selectively the output from said conversion means or a fixed value; and inversion means for receiving the output from said selection means and inverting the magnetic field when the output from said conversion means becomes a predetermined value different from said fixed value; wherein said control means controls said magnetic head by controlling said selection means and said inversion means.
According to a fifth aspect of this invention, said control means controls said selection means to output the fixed value when said magnetic head applies the DC magnetic field to said record medium, said control means controls said conversion means to output the record data having the intermediate frequency within the predetermined frequency range when applying the magnetic field that is inverted at the constant period, and said control means controls said conversion means to output the record data that is inverted in accordance with the record data when applying to said record area the magnetic field that is inverted in accordance with the record data.
In accordance with a sixth aspect of the invention, a method of recording record data on a predetermined area of a magnetic record medium comprises the steps of: applying a DC magnetic field to the predetermined area; applying to the predetermined area a magnetic field that is inverted at a constant period corresponding to a frequency within a frequency range of the record data; and applying to the predetermined area a magnetic field that is inverted in accordance with the record data.
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Patent Abstracts of Japan, JP 62-097106, Published May 6, 1987, Mitsubishi Electric Corp.
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Kim W. Chris
Limbach & Limbach L.L.P.
Sony Corporation
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