Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
2001-09-06
2004-04-13
Hudspeth, David (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
C360S048000, C360S072100
Reexamination Certificate
active
06721123
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic tape recording medium including data tracks, a magnetic tape recording and reproducing apparatus for recording and reproducing data tracks, a magnetic tape recording method, and a magnetic tape cassette.
As a linear system for recording and reproducing data tracks existing in the data area of a magnetic tape, there is known an LTO (Linear Tape Open) standard.
In a linear system, a magnetic tape including a servo track recorded in the longitudinal direction of the magnetic tape is fed in the longitudinal direction thereof. A fixed magnetic head is contacted with the servo track to thereby read out a servo track signal recorded in the servo track in the longitudinal direction of the magnetic tape. While controlling the magnetic head so as to restrain an offtrack error, a data track existing in the data area of a magnetic tape and arranged in parallel to the servo track is traced accurately to thereby record and reproduce the data track.
Further, in the linear system, a position information signal encoded in the servo track signal is read out to thereby cue up the data of the data track.
On the other hand, in a helical system in which, differently from the above linear system, a data track existing in the data area of a magnetic tape is arranged obliquely. A servo track signal recorded in a servo track existing in one end of the magnetic tape and extending in the longitudinal direction of the magnetic tape is read out. In accordance with a servo tracking signal, while controlling a drum magnetic head, a drum magnetic head is controlled so as to restrain an off-track error.
Also, in the case of the data cueing, as in a DDS (Digital Data Storage) system, a position information signal embedded (superimposed) into the data is read out; or, as in a D1 system, a position information signal is recorded in the longitudinal direction of a magnetic tape simultaneously when the data is recorded.
However, in either of the above-mentioned conventional systems, there is a possibility that, in case where the magnetic tape is deformed in shape or changed in dimension due to the temperature and humidity, the servo track signal or position information signal cannot be read out accurately, thereby making it impossible to read out the data.
In the linear system, in case where the magnetic tape is deformed in shape or changed in dimension, the distance between the servo track and data area is caused to vary, with the result that there can occur an offtrack error or mutually adjoining servo tracks or data tracks can be overwritten.
Also, in the helical system, in case where the magnetic tape is deformed in shape or changed in dimension, the azimuth angle is caused to vary or the pitch distance of the data track is caused to vary (especially, reduce), which makes it impossible to read out the data with accuracy.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the drawbacks found in the above-mentioned conventional systems. Accordingly, it is an object of the invention to provide a magnetic tape recording medium, a magnetic tape recording and reproducing apparatus, a magnetic tape recording method, and a magnetic tape cassette which are respectively enhanced in durability against the shape deformation or dimensional change of a magnetic tape.
In attaining the above object, according to a first aspect of the invention, there is provided a magnetic tape recording medium for magnetically recording and reproducing data tracks sequentially with respect to the data area of a magnetic tape at an azimuth angle &thgr;°, wherein the magnetic tape includes two servo tracks respectively situated in the portions of the magnetic tape existing inwardly of the width-direction two end portions of the magnetic tape and formed in a belt-like shape extending in parallel to the longitudinal direction of the magnetic tape, each of the servo tracks having therein a previously recorded servo track signal including position information recorded in the longitudinal direction of the magnetic tape for representing the position of the magnetic tape and tracking information recorded in parallel to the data tracks, and also wherein the azimuth angle &thgr;° satisfies an equation of
0≦&thgr;≦tan
−1
(10
p/a×L
),
where the tape width of the magnetic tape is expressed as L (m), a data track pitch in the data area is expressed as p (m), and the longitudinal-direction greatest dimension change rate of the magnetic tape due to the temperature and humidity is expressed as a (%)
According to the present magnetic tape recording medium, even in case where the magnetic tape recording medium is deformed in shape or changed in dimension, there can be eliminated an offtrack error and thus the data tracks can be traced accurately in the data area of the magnetic tape.
Also, since the servo tracks are respectively disposed inwardly of the tape-width-direction two end portions of the magnetic tape, the tracking accuracy of the magnetic tape recording medium can be enhanced.
Further, because the servo track signal is previously recorded in each of the servo tracks, there can be reduced a harmful effect on tracing variations inevitably occurring in the recording and reproducing operations of a magnetic tape recording and reproducing apparatus which is used to record and reproduce the magnetic tape recording medium.
The magnetic tape recording medium according to the invention is also characterized in that the servo tracks are disposed so as to place the data area between them in the magnetic tape width direction and also that the position information of the servo track signal is magnetically recorded in the longitudinal direction of the magnetic tape.
That is, according to the present magnetic tape recording medium, since the servo tracks are disposed such that they exist inwardly of the tape-width-direction two end portions while the data area of the magnetic tape is interposed between them, the tracking accuracy thereof can enhanced.
Also, even in case where the magnetic tape recording medium is deformed in shape or changed in dimension, because the position information is magnetically recorded in the longitudinal direction of the magnetic tape, a read error is hard to occur.
In the magnetic tape recording medium according to the invention, the servo tracks are situated so as to place the data area between them in the magnetic tape width direction, and also that the position information of the servo track signal has a pattern formed in the longitudinal-direction magnetic surface of the magnetic tape so as to be optically readable. Instead of the pattern, the position information of the servo track signal may have a bit hole formed in the longitudinal direction of the magnetic tape.
That is, according to the present magnetic tape recording medium, since the servo tracks are disposed such that they exist inwardly of the tape-width-direction two end portions while the data area of the magnetic tape is interposed between them, the tracking accuracy thereof can enhanced.
Also, even in case where the magnetic tape recording medium is deformed in shape or changed in dimension, because the position information is composed of a pattern formed in the magnetic surface of the magnetic tape in the longitudinal direction of the magnetic tape so as to be optically readable, or a bit hole formed recorded in the longitudinal direction of the magnetic tape, a read error is hard to occur.
It is preferable for the magnetic tape recording medium according to the invention that the position information of the servo track signal is composed of a pattern magnetically recorded in the longitudinal direction of the magnetic tape on the opposite surface of the magnetic surface where the data area is to be recorded, or a pattern which is formed on the present opposite surface so as to be optically readable.
That is, according to the present magnetic tape record medium, even in case where the magnetic tape recording medium is deformed in shape or changed in dimension, bec
Ejiri Kiyomi
Morita Kiyoo
Sueki Minoru
Fuji Photo Film Co. , Ltd.
Hudspeth David
Olson Jason
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