JPH039523B2 - - Google Patents
Info
- Publication number
- JPH039523B2 JPH039523B2 JP59113059A JP11305984A JPH039523B2 JP H039523 B2 JPH039523 B2 JP H039523B2 JP 59113059 A JP59113059 A JP 59113059A JP 11305984 A JP11305984 A JP 11305984A JP H039523 B2 JPH039523 B2 JP H039523B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- head
- erasing
- track
- adjacent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000005405 multipole Effects 0.000 claims description 9
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000005611 electricity Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/325—Erasing heads using permanent magnets
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/02—Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
- G11B5/024—Erasing
Description
【発明の詳細な説明】
〔発明の技術分野〕
本発明は多極マグネツト消去ヘツドを用いた磁
気消去装置に関する。DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION The present invention relates to a magnetic eraser using a multipolar magnetic erase head.
永久磁石材料の表面に複数のＳ極およびＮ極を
交互に着磁してなる多極マグネツト消去ヘツド
は、交流消去装置に比較し価格が安いこと、消去
のための電力が不要なことなどの利点により一般
に広く使用されている。
A multi-pole magnetic erase head, which is made by alternately magnetizing a plurality of S and N poles on the surface of a permanent magnet material, has advantages such as being cheaper than an AC eraser and requiring no electricity for erasing. Widely used due to its advantages.
従来この多極マグネツト消去ヘツドを多トラツ
クテープレコーダ等に使用する場合においては、
消去しようとするトラツクに隣接したトラツクを
部分的に消去するという欠点があつた。これは多
極マグネツト消去ヘツドからの漏洩磁界が消去し
ようとするトラツク以外にも拡がるために起こる
ものであり、特に高トラツク密度の記録媒体にお
いてはその影響が大であつた。 Conventionally, when using this multi-pole magnetic erase head in a multi-track tape recorder, etc.,
This method has the disadvantage that tracks adjacent to the track to be erased are partially erased. This occurs because the leakage magnetic field from the multi-pole magnetic erase head spreads beyond the track to be erased, and its influence was particularly large on recording media with high track densities.
本発明はこのような点に鑑みてなされたもの
で、隣接トラツクに影響を及ぼすことのない磁気
消去装置を提供することを目的とするものであ
る。
The present invention has been made in view of these points, and it is an object of the present invention to provide a magnetic erasing device that does not affect adjacent tracks.
本発明は隣り合うＳ極、Ｎ極間距離を磁気記録
媒体のトラツク間に存在する無記録部分の幅より
も小さくなるように着磁して成る多極マグネツト
消去ヘツドを用いて信号消去するようにしたもの
である。
The present invention erases signals using a multi-pole magnetic erase head which is magnetized so that the distance between adjacent south and north poles is smaller than the width of the non-recorded area between tracks of a magnetic recording medium. This is what I did.
このような磁気消去装置によると隣接トラツク
を消去することがなくなり、また消去効果の向上
を図ることができる。
According to such a magnetic erasing device, adjacent tracks are not erased, and the erasing effect can be improved.
以下本発明を図面を参照して詳細に説明する。 The present invention will be explained in detail below with reference to the drawings.
第１図は本発明の一実施例を説明するための図
である。図において１は本発明で用いる多極マグ
ネツト消去ヘツド（以下単に消去ヘツドという）
であり、Ｓ極およびＮ極が交互に着磁されてい
る。また２は多トラツク記録媒体上のトラツクで
ある。消去ヘツド１はそのＳ極およびＮ極の着磁
幅、すなわちトラツク幅とを交する方向の長さが
隣り合うＳ極およびＮ極でほぼ等しく設定されて
いる。また隣り合うＳ，Ｎ極間が記録媒体のトラ
ツク間に存在する無記録部分の幅よりも小さくな
るように着磁されている。このような消去ヘツド
を用いると隣接トラツクを消去することなく希望
のトラツクの信号のみを正確に消去することがで
きる。この理由をトラツク幅をＴ、トラツク間に
存在する無記録部分の幅をＷ、消去ヘツドの幅を
We多極マグネツト消去ヘツドの隣り合うＳ，Ｎ
極の各着磁幅およびこれらＳ，Ｎ極間距離をＰと
して以下に説明する。 FIG. 1 is a diagram for explaining one embodiment of the present invention. In the figure, 1 is a multi-polar magnetic erase head (hereinafter simply referred to as erase head) used in the present invention.
The S and N poles are alternately magnetized. Further, 2 is a track on a multi-track recording medium. In the erase head 1, the magnetized widths of the S and N poles, that is, the lengths in the direction crossing the track width, are set to be approximately equal for adjacent S and N poles. Further, the magnetic field is magnetized so that the width between the adjacent S and N poles is smaller than the width of the non-recorded portion existing between the tracks of the recording medium. By using such an erasing head, only the signal of a desired track can be accurately erased without erasing adjacent tracks. The reason for this is that the track width is T, the width of the unrecorded area between tracks is W, and the width of the erase head is
Adjacent S and N of We multipolar magnetic erase head
Each magnetized width of the poles and the distance between these S and N poles will be described below as P.
消去ヘツド１の位置はテープレコーダの設計事
項であるが、テープの上下動および隣接トラツク
を消去しないための条件から第１図に示すように
消去ヘツド１の側端が無記録部分の中央に位置す
るように選ばれる。すなわち消去ヘツド１の側端
から隣接トラツクの端までの距離はW/2となる。 The position of the erasing head 1 is a matter of tape recorder design, but due to the vertical movement of the tape and the conditions for not erasing adjacent tracks, the side edge of the erasing head 1 is located in the center of the unrecorded area as shown in Figure 1. chosen to do. That is, the distance from the side edge of erasing head 1 to the edge of the adjacent track is W/2.
消去ヘツドの側端から漏れる磁界強度は、一般
にマグネツト表面の最大磁界強度をＨ、消去ヘツ
ド１の側端からの距離をｄ、消去ヘツド１表面で
の隣り合うＳ，Ｎ極間距離をＰとすると、
He-〓d/pにより表わすことができる。これは磁気
記録再生におけるスペースロスの理論He-2〓d/〓
（λ：波長）においてλ＝2Pとおくことにより得
られるものであり、実験的にもよい一致が得られ
る。本実施例においてはｄ＝W/2としているから
消去ヘツド１の側端から漏洩磁界強度は
He-2〓W/2P
と表わされる。 The strength of the magnetic field leaking from the side edge of the erase head is generally expressed as follows: H is the maximum magnetic field strength on the surface of the magnet, d is the distance from the side edge of the erase head 1, and P is the distance between adjacent S and N poles on the surface of the erase head 1. Then,
It can be expressed as He - 〓 d/p . This is the theory of space loss in magnetic recording and reproduction He -2 〓 d/ 〓
This can be obtained by setting λ=2P in (λ: wavelength), and good agreement can be obtained experimentally. In this embodiment, since d=W/2, the strength of the magnetic field leaking from the side edge of the erasing head 1 is expressed as He -2 〓 W/2P .
このような漏洩磁界の強度が隣接トラツクに影
響を与えないためには、第２図の記録媒体のＢ−
Ｈカーブから明らかなように、隣接トラツクの位
置において漏洩磁界の強度が記録媒体の抗磁力
Hcの1/2以下でなければならない。したがつて
He-〓W/2P＜Hc／２
を満足しなければならない。またマグネツト表面
での磁界強度Ｈは消去しようとするトラツクを充
分に消去するためには第２図に示すように記録媒
体の抗磁力Hcの少なくとも２倍の磁界が必要で
ある。したがつて
2Hc e-〓W/2P＜Hc／２
e-〓/2(W/P)＜1/4
∴Ｗ／Ｐ＞−2ln（１／４）／πlne＝0.91.0
∴Ｐ＜Ｗ
すなわち隣り合う磁極間距離Ｐを無記録部分の幅
Ｗよりも小さくすることにより隣接トラツクへの
影響をなくすことができる。 In order to prevent the strength of such leakage magnetic field from affecting adjacent tracks, it is necessary to
As is clear from the H curve, the strength of the leakage magnetic field at the position of the adjacent track is equal to the coercive force of the recording medium.
Must be less than 1/2 of Hc. Therefore, He - 〓 W/2P < Hc/2 must be satisfied. Furthermore, in order to sufficiently erase the track to be erased, the magnetic field strength H on the surface of the magnet needs to be at least twice the coercive force Hc of the recording medium, as shown in FIG. Therefore, 2Hc e - 〓 W/2P ＜Hc／2 e - 〓 /2(W/P) ＜1/4 ∴W/P＞−2ln(1/4)/πlne＝0.91.0 ∴P＜W That is, by making the distance P between adjacent magnetic poles smaller than the width W of the non-recorded portion, the influence on adjacent tracks can be eliminated.
この発明によりカセツトテープレコーダ用多極
マグネツト消去ヘツドを作るためには、カセツト
テープでは無記録部分の幅Ｗが0.8mmに規格され
ているので、隣り合う磁極間距離Ｐを0.8mm以下
にする。また9.25mm幅テープを用いた４トラツク
テープレコーダの場合には、テープの無記録部分
の幅Ｗが0.75mmに規格されているので、隣り合う
磁極間距離Ｐを0.75mm以下にする。 In order to produce a multi-pole magnetic erase head for a cassette tape recorder according to the present invention, since the width W of the non-recorded portion of a cassette tape is specified as 0.8 mm, the distance P between adjacent magnetic poles should be set to 0.8 mm or less. In the case of a 4-track tape recorder using a 9.25 mm wide tape, the width W of the non-recorded portion of the tape is specified as 0.75 mm, so the distance P between adjacent magnetic poles should be 0.75 mm or less.
以上のように本発明によると隣接トラツクを消
去することのない多極マグネツト消去ヘツドを用
いた磁気消去装置を提供することができる。 As described above, according to the present invention, it is possible to provide a magnetic erasing device using a multi-pole magnetic erasing head that does not erase adjacent tracks.
第１図は本発明の一実施例に係る多極マグネツ
ト消去ヘツドを用いた磁気消去装置を説明するた
めの図、第２図は記録媒体のＢ−Ｈカーブを示す
図である。
１……多極マグネツト消去ヘツド、２……記録
トラツク、Ｓ……Ｓ極、Ｎ……Ｎ極。
FIG. 1 is a diagram for explaining a magnetic erasing device using a multipolar magnetic erasing head according to an embodiment of the present invention, and FIG. 2 is a diagram showing a B-H curve of a recording medium. 1...Multi-pole magnetic erase head, 2...Recording track, S...S pole, N...N pole.
Claims (1)
交互に着磁した多極マグネツト消去ヘツドを、複
数トラツク記録された磁気記録媒体上の任意のト
ラツク上に、その側端が隣接するトラツク間の無
記録部分のほぼ中央に位置するように配置して選
択的に信号消去を行う磁気消去装置であつて、前
記多極マグネツト消去ヘツドの隣り合うＳ、Ｎ極
間距離が前記隣接するトラツク間の無記録部分の
幅よりも小さくなるよう着磁されてなることを特
徴とする磁気消去装置。1. A multi-pole magnetic erase head, in which a plurality of S and N poles are alternately magnetized on the surface of a permanent magnet material, is placed on any track on a magnetic recording medium on which multiple tracks have been recorded, and the side edges of the head are placed on adjacent tracks. A magnetic erasing device for selectively erasing signals by disposing the multi-pole magnetic erasing head approximately in the center of a non-recorded portion between adjacent tracks; A magnetic erasing device characterized in that it is magnetized so that the width is smaller than the width of the non-recorded portion between them.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11305984A JPS60121504A (en) | 1984-06-04 | 1984-06-04 | Signal erasion system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11305984A JPS60121504A (en) | 1984-06-04 | 1984-06-04 | Signal erasion system |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8191877A Division JPS5417713A (en) | 1977-07-11 | 1977-07-11 | Multipole magnet erase head |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60121504A JPS60121504A (en) | 1985-06-29 |
| JPH039523B2 true JPH039523B2 (en) | 1991-02-08 |
Family
ID=14602454
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11305984A Granted JPS60121504A (en) | 1984-06-04 | 1984-06-04 | Signal erasion system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60121504A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69219105T2 (en) * | 1992-02-26 | 1997-07-24 | Tandberg Data | Method and device for erasing information from a magnetic tape |
| US5959812A (en) * | 1997-07-25 | 1999-09-28 | Imation Corp. | Fringe field compensation system for multi-track servo recording head |
-
1984
- 1984-06-04 JP JP11305984A patent/JPS60121504A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60121504A (en) | 1985-06-29 |
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