Dynamic magnetic information storage or retrieval – Head – Gap spacer
Reexamination Certificate
1999-03-08
2001-08-07
Evans, Jefferson (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Gap spacer
C122S125000
Reexamination Certificate
active
06271990
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic recording apparatus for overwriting data on a magnetic recording medium with, for example, a magnetic head mounted on a rotary drum, and more specifically, to a magnetic recording apparatus for stabilizing the recorded state of tracks to which data is overwritten.
2. Description of the Related Art
In magnetic recording apparatuses used in video equipment and magnetic recording apparatuses for writing data for computers, a magnetic head is mounted on the rotary drum of a rotary head unit, and a magnetic tape travels in helical contact with the rotary drum as well as the rotary drum rotates so that a recording operation is carried out to the magnetic tape in a helical scan system.
Among this type of the magnetic recording apparatuses, there is a magnetic recording apparatus which uses a magnetic head having a magnetic gap whose track width Tw is larger than the pitch Tp of tracks recorded on a magnetic tape and overwrites data to the magnetic tape by scanning the magnetic head so that the magnetic gap overwrites the track of the magnetic tape where data is already written.
FIG. 5
is a plan view showing the tape sliding surface of the magnetic head mounted on the rotary drum of the magnetic recording apparatus in an enlarged fashion.
A magnetic gap G is formed to a portion of the tape sliding surface of the magnetic head where cores
1
and
2
, which are formed of a magnetic material having a high magnetic permeability, are jointed in confrontation with each other through a non-magnetic material layer. Although the magnetic gap G has an azimuth angle which is inclined by a minute angle with respect to a direction (X-direction) orthogonal to a scanning direction Y, the magnetic gap G is shown at a right angle with respect to the scanning direction Y in this specification.
Symbol Tw denotes the track width of the magnetic gap G. The track width Tw is determined by the depth of core regulating grooves
3
,
3
formed to a V-shape on both the right and left sides of the cores
1
,
2
at the portion where they are jointed to each other. In a magnetic gap G which is actually formed with an azimuth angle, the track width Tw means the size between both the edges G
1
-G
2
of the inclined magnetic gap G in the track width direction (X-direction). Further, when the distance between the overwrite edge G
1
of the magnetic gap G and the side edges of the cores
1
,
2
is denoted by symbol L
1
and the distance between the other edge G
2
and the side edges of the cores
1
,
2
is denoted by symbol L
2
, L
1
=L
2
is established in the magnetic head used in the conventional magnetic recording apparatus and the center of the track width Tw of the magnetic gap G matches the center CL of the cores
1
,
2
in the width direction thereof.
SUMMARY OF THE INVENTION
When data is recorded by overwrite using the conventional magnetic head, a recorded pattern is made unstable on the track where data is recorded on a magnetic tape, and, in particular, data recorded by the portion of the overwrite edge G
1
of the magnetic gap G is made unstable. As a result, when overwritten magnetic information is reproduced, there arises problems such as a reproduced output is varied, and the like.
In particular, the pitch of tracks recorded on a magnetic tape is recently made narrower to realize recording of a high density in correspondence to the transfer of recorded data in a high density, and there is proposed a recording format having a track pitch of about 10 &mgr;m or less. In the magnetic recording made using such a narrow track pitch, unstable recording of data in the overwrite edge G
1
has a significant effect as the variation of a reproduced output.
Reasons why the unstable recording is caused are as described below.
Although the tape sliding surface of the magnetic head shown in
FIG. 5
is formed to a curved shape in the scanning direction (Y-direction), it is also formed to a curved shape in the track width direction (X-direction). This is caused by that when the tape sliding surface is polished in the scanning direction (Y-direction), it is also formed to the curved shape in the X-direction at the same time. Then, the apex of the curved surface in the X-direction approximately matches the center CL of the cores
1
,
2
in the width direction thereof.
Since the center of the track width Tw of the magnetic gap G approximately matches the center CL of the cores
1
,
2
in the width direction thereof, the overwrite edge G
1
of the magnetic gap G is located at a position apart from the center CL so that the overwrite edge G
1
is located at a position which retreats in a direction where it is somewhat apart from the tape with respect to the apex of the curved surface at the center CL. As a result, the portion of the overwrite edge G
1
unstably touches the magnetic tape, whereby the recorded pattern is made unstable and the reproduced output is varied.
FIG. 6
shows the state that magnetic data is overwritten to the magnetic tape with the magnetic head shown in FIG.
5
.
In
FIG. 6
, symbol D
1
denotes data initially recorded on the magnetic tape which is scanned with the magnetic gap G and a center CL in the core width direction at the time is denoted by symbol CL
1
. Next, symbol D
2
denotes magnetic data recorded on the magnetic tape which is scanned with the magnetic gap G while partially overlapping the magnetic gap G to the data D
1
in a track width direction. The pitch Tp of a data track Dt which is left by overwrite is determined by the position of the overwrite edge G
1
of the magnetic gap G.
As shown in
FIG. 6
, the data track Dt which is left from the initially recorded magnetic data D
1
is data recorded at a portion of the magnetic head which is greatly apart from the center CL of the tape sliding surface of the magnetic head in the core width direction thereof. That is, the data which is recorded at the portion of the magnetic head where the magnetic gap touches the magnetic tape in a bad state is left as the data track Dt. In particular, a data boundary De in overwrite is recorded with the edge G
1
of the magnetic gap G which is greatly apart from the center CL of the tape sliding surface in the core width direction thereof, data is liable to be unstably recorded at the boundary De.
An object of the present invention for solving the above conventional problem is to provide a magnetic recording apparatus capable of suppressing the great variation of a reproduced output by stabilizing the recorded pattern of a data track left to a recording medium by overwrite.
A magnetic recording apparatus of the present invention for carrying out an overwrite operation so that a magnetic gap having a prescribed track width overlaps the recording track having been recorded on the magnetic recording medium in the track width direction thereof by scanning a magnetic recording medium with a magnetic head to which the magnetic gap is formed at the portion thereof where cores composed of a magnetic material are confronted with each other is characterized in that the magnetic gap is formed by being offset with respect to the core width in the magnetic head so that the overwrite edge of the magnetic gap is offset to the center of the core width.
The magnetic recording apparatus of the present invention is arranged such that a magnetic head is mounted on the rotary drum of a rotary head unit, a magnetic tape travels in helical contact with the rotary head unit, the rotary drum is rotated and the magnetic tape is helically scanned with the magnetic head. Otherwise, the magnetic recording apparatus is such that a magnetic head may scan a magnetic tape in a plane fashion and overwrite may be carried out at the time or overwrite may be carried out when a disc-shaped magnetic recording medium is scanned with a magnetic head.
More specifically, according to the present invention, it is preferable that Tw−Tp=L
1
−L
2
(however, L
1
>L
2
) is established, where Tw represents the track
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Evans Jefferson
LandOfFree
Magnetic recording apparatus having a magnetic head for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Magnetic recording apparatus having a magnetic head for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic recording apparatus having a magnetic head for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2438183