GB2274018A - Magnetic head - Google Patents
Magnetic head Download PDFInfo
- Publication number
- GB2274018A GB2274018A GB9402110A GB9402110A GB2274018A GB 2274018 A GB2274018 A GB 2274018A GB 9402110 A GB9402110 A GB 9402110A GB 9402110 A GB9402110 A GB 9402110A GB 2274018 A GB2274018 A GB 2274018A
- Authority
- GB
- United Kingdom
- Prior art keywords
- core
- erase
- read
- magnetic
- write
- 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.)
- Granted
Links
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
- G11B5/265—Structure or manufacture of a head with more than one gap for erasing, recording or reproducing on the same track
- G11B5/2652—Structure or manufacture of a head with more than one gap for erasing, recording or reproducing on the same track with more than one gap simultaneously operative
- G11B5/2654—Structure or manufacture of a head with more than one gap for erasing, recording or reproducing on the same track with more than one gap simultaneously operative for recording or erasing
- G11B5/2655—Structure or manufacture of a head with more than one gap for erasing, recording or reproducing on the same track with more than one gap simultaneously operative for recording or erasing with all the gaps disposed within the track or "guard band" between tracks, e.g. with erase gaps operative on track edges, with wide erase gap followed by narrow write gap
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Magnetic Heads (AREA)
Abstract
In a magnetic head comprising a read/write head and an erase head constructionally integrated with each other, the closed magnetic circuit of the erase head (11) is arranged to be higher in magnetic reluctance than the closed magnetic circuit of the read/write head (1), whereby a magnetic flux to be drawn by the erase gap is reduced so as to prevent the leakage of the magnetic flux to the read/write head side. This is achieved by having a cross-section area in the erase circuit (S1) less than any cross-section in the read/write circuit. The area may be reduced by roughening a contact surface or by positioning of non-magnetic spacers. <IMAGE>
Description
MAGNETIC HEAD
The present invention relates to magnetic heads for use in magnetic disk or flexible disk devices.
Fig. liof the accompanying drawings is a perspective view of an arrangement of a conventional magnetic head such as disclosed in Japanese
Patent Application Laid-Open No. 61-39910. In Fig. 11, numeral 1 represents a read/write core having a substantially T-shaped configuration and made of a magnetic material such as a Mn-Zn ferrite, and 2 designates a center core made of a magnetic material similar to that of the read/write core 1. This center core 2 is coupled to the read/write core ; by a non-magnetic bonding material 3 such as a glass so as to form a read/write gap 4 between the center core 2 and the read/write core 1 on a medium-sliding surface la. Numeral 5 depicts an erase core having a substantially T-shaped configuration and made of a magnetic material such as Mn-Zn ferrite.This erase core 5 is coupled to the center core 2 by a non-magnetic bonding material 6 such as a glass so as to form an erase gap 7 therebetween on a medium-sliding surface Sa. Numeral 8 denotes a back core for closing the magnetic paths made by the read/write core 1, center core 2 and erase core 5, 9 designates a read/write coil wound around a leg lb of the read/write core 1, 10 is an erase coil wound around a leg 5b of the erase core 5.
The conventional magnetic head shown in Fig. 11 is arranged by an integration of a read/write head formed with a closed magnetic circuit comprising the read/write core 1, back core 8 and center core 2, and an erase head formed with an closed magnetic circuit comprising the erase core 5, back core 8 and center core 2.
Figs. 12(a) and 12(b) are a top plan view and an elevation side view for describing the flow of a magnetic flux when the magnetic head illustrated in Fig. 11 is taking the reproducing state, where parts corresponding to those in Fig. 11 are marked with the same numerals and characters and the detailed description thereof will be omitted. In the illustrations, ( 0 R), ( 0 R1), ( 0 R2), ( f R3) represent the magnetic fluxes of signals to be reproduced through the read/write gap 4, and ( 0 E), ( 0 El), ( 9 E2), ( d E3) designate the magnetic fluxes of signals to be reproduced through the erase gap 7.
A description will be made hereinbelow in terms of operation of the above-mentioned conventional magnetic head.
In cases where data recorded on a medium (not shown) are reproduced by using the conventional magnetic head, the read/write gap 4 draws a slight leakage flux on t)ie medium so as to form a closed loop of the magnetic fluxes ( 9 R1) and ( 0 R2) passing through the closed magnetic circuit comprising the read/write core 1, back core 8 and center core 2. Here, a portion of the drawn magnetic flux is leaked into the erase core 5 to become a leakage flux ( 0 R3). At this time, the magnetic flux ( 0 R1) passing through the read/write core 1 causes induction to the read/write coil 9 so that the reproduced data signal flows through the read/write coil 9.Further, at this time, in the case that the erase gap 7 is positioned on a track of data to be reproduced or a track adjacent thereto, the erase gap 7 similarly draws a slight leakage flux on the medium so as to form a closed loop of the magnetic fluxes ( X El) and ( 9 E2) passing through the closed circuit comprising the erase core 5, back core 8 and center core 2, a portion thereof being leaked into the read/write core 1 to become a leakage flux ( 0 E3).
According to the conventional magnetic head with the above-described arrangement, in the case of reproducing data recorded on a medium, the magnetic flux ( 0 R1) drawn by the read/write gap 4 and the magnetic flux ( 0 E3) drawn by the erase gap 7 respectively pass through the read/write core 1 so as to cause induction to the read/write coil 9 whereby a signal induced by a superimposed magnetic flux of the magnetic fluxes ( 9 R1) and ( 0 E3) passes through the read/write coil 9 to perform the reproduction.In this case, since the data drawn by the read/write gap 4 are generally different from the data drawn by the erase gap 7, the data drawn by the erase gap 7 result in noises on the reproduced signal from the read/write coil 9 to cause generation of errors and reduction of the margin, thereby lowering the reliability on the reproducing performance of the magnetic head.
It is therefore an object of the present invention to eliminate the aforementioned problems to provide a magnetic head which is capable of reducing the magnetic flux to be drawn by the erase gap to prevent the magnetic flux from being leaked to the read/write head side and to suppress the generation of errors and reduction of the margin, thereby increasing the performance and reliability.
According to the present invention, there is provided a magnetic head comprising a read/write core made of a magnetic material, a centre core made of a magnetic material and coupled to said read/write core so as to form a read/write gap therebetween on a surface over which a recording medium is to slide, an erase core made of a magnetic material and coupled to said centre core so as to form an erase gap therebetween on said surface, and a back core made of a magnetic material and coupled to said read/write core, said centre core and said erase core so as to form a closed magnetic circuit, wherein a crosssectional area transverse to the magnetic flux direction of a portion or all of the core forming the erase-head side magnetic circuit is smaller than a cross-sectional area of the core forming the read/write-head side magnetic circuit.
Thus, the magnetic head is arranged such that the cross-sectional area of a portion or all of the erasehead side back core which is perpendicular to the magnetic path is smaller than the cross-sectional area of the read/write head side back core which is also perpendicular to the magnetic path.
The magnetic head can be arranged such that the erase core and the centre core, and the centre core and the read/write core are coupled through a plurality of back cores to each other, the number of the back cores at the erase head side being smaller than that of the back cores at the read/write head side.
In another embodiment, the magnetic head can be arranged such that the back core is composed of two back cores and respectively positioned at the erase head and read/write head sides of the centre core with the spacer for the separation between the erase head and the read/write head being interposed therebetween, and the cross-sectional area of the back core where the spacer is positioned at the read/write head side is smaller than that of the back core where the spacer is positioned at the erase head side, the cross-sectional areas of the back cores being perpendicular to the magnetic path.
In another embodiment, the magnetic head can be arranged such that a portion or all of the surface of the erase-head side back core is machined to be rougher as compared with the surface of the read/write core, or such that the coupling portion of the erase core to the back core is machined to be rougher as compared with the coupling portion of the read/write core to the back core.
In another embodiment, the magnetic head can be arranged such that the contact area of the coupling portion between the back core and the erase core is smaller than that of the coupling portion between the back core and the read/write core.
Alternatively, a magnetic head according to the invention can be arranged such that, without providing the back core to be coupled to the read/write core, the centre core and the erase core, the read/write head constructed with a closed magnetic circuit comprising the centre core and the read/write core is integrally coupled to the erase head constructed with a closed magnetic circuit comprising the centre core and the erase core, and the coupling portion of the erase core and the centre core is machined to be rougher as compared with the coupling portion of the read/write core and the centre core.
In another embodiment, the magnetic head can be arranged so that the contact area of the coupling portion between the erase core and the centre core is smaller than that of the coupling portion between the read/write core and the centre core.
In the magnetic head according to the invention, since the closed magnetic circuit of the erase head is greater in magnetic reluctance than the closed magnetic circuit of the read/write head, the leakage of the signal reproduced by the erase head to the read/write head can be reduced.
The invention will be further described by way of non-limitative example, with reference to the accompanying drawings, in which:
Figure 1 is a perspective view showing a magnetic head according to an embodiment of the invention;
Figure 2 is a perspective view showing a magnetic head according to an embodiment of the invention;
Figure 3 is a perspective view showing a magnetic head according to an embodiment of the invention;
Figure 4 is a perspective view showing a magnetic head according to an embodiment of the invention;
Figures 5 and 6 are perspective views showing a magnetic head according to an embodiment of the invention;
Figure 7 is a perspective view showing a magnetic head according to an embodiment of the invention;
Figure 8 is a perspective view showing a magnetic head according to an embodiment of the invention;;
Figure 9 is a perspective view showing a magnetic head according to an embodiment of the invention;
Figure 10 is a perspective view showing a magnetic head according to an embodiment of the invention;
Figure 11 is a perspective view showing a conventional magnetic head; and
Figures 12(a) and (b) are schematic illustrations for the flow of the magnetic flux in the reproducing process of the magnetic head shown in Figure 11.
Figure 1 shows a detailed arrangement of a magnetic head according to the invention. In Figure 1, a non-magnetic spacer 111 such as a glass is provided in the back core 8 so as to effect the separation between the erase head and the read/write head, and the spacer 111 is shifted to the erase head side with respect to the centre of the centre core 2 whereby the magnetic reluctance of the erase head side becomes great so as to lower the reproduction efficiency. As a result, the magnetic flux + E to be drawn by the erase gap 7 in reproduction is reduced and hence the magnetic flux Q, E3 to be leaked into the read/write head is also reduced.
Figure 2 shows another embodiment in which the cross-sectional area S1 of a portion or entire of the erase-head side back core 8E which crosses the magnetic path is arranged to be smaller than the cross-sectional area S1 of the read/write-head side back core 8W which also crosses the magnetic path. Thus, similarly, the magnetic reluctance of the erase head side becomes high so as to lower the reproduction efficiency, whereby the magnetic flux 0 E to be drawn by the erase gap 7 in reproduction is reduced so as to reduce the magnetic flux 0 E3 to be leaked into the read/write head.
Further, as illustrated in Fig. 3, the erase core 5 and center core 2, the center core 2 and read/write core 1 are respectively coupled to each other through a plurality of back cores 8, and the number of the erase-head side back cores 8E is arranged to be smaller than the number of the read/write-head side back cores 8W. This also allows increase in the magnetic reluctance of the erase head.
Thus, the reproduction efficiency can be reduced so that the magnetic flux 0 E to be drawn by the erase gap 7 in reproduction is reduced so as to reduce the magnetic flux 0 E3 to be leaked into the read/write head.
Fig. 4 shows a further embodiment in which two back cores 8 are provided which respectively have at the erase-head side and read/write-head side of the center core 2 non-magnetic spacers 111 such as glass formed so as to separate the back cores 8 into the erase head sides and the read/write sides. The cross-sectional area S1 of the back core 8 of which the spacer ill is positioned at the read/write-head side is arranged to be smaller than the cross-sectional area S2 of the back core 8 of which the spacer 111 is positioned at the erase-head side, the cross-sectional areas S1 and S2 crossing the magnetic paths.
Thus, the magnetic reluctance of the erase head become high so as to lower the reproduction efficiency whereby the magnetic flux 9 E to be drawn by the erase gap 7 in reproduction can be reduced so as to reduce the magnetic flux 0 E3 to be leaked into the read/write head.
In Figs. 5 and 5. a portion (the coupling portion to the erase core) or all of the surface of the erase-head side back core 8E is machined to be rougher as compared with the surface of the read/write core 1 so as to increase the magnetic reluctance of the erase head.
In Fig. 7, the coupling portion of the erase core 5 to the back core 8 is machined to be rougher than the read/write core 1, whereby the magnetic reluctance of the erase head can be heightened.
In Figure 8, the contact area S3 of the coupling portion between the back core 8 and the erase core 5 is arranged to be smaller than the contact area S4 of the coupling portion between the back core 8 and the read/write core 1, thereby increasing the magnetic reluctance of the erase head. Thus, the reproduction efficiency can be reduced and the magnetic flux + E to be drawn by the erase gap 7 in reproduction can be reduced so as to reduce the magnetic flux + E3 to be leaked into the read/write head.
Further, it is also appropriate that the magnetic head is constructed as illustrated in Figure 9, that is, the back core 8 and the erase core 5 are constructionally integrated with each other so as to form a closed magnetic circuit with the erase core 5 and the centre core 2 without independently providing the back core 8. In this case, a means for more heightening the magnetic reluctance of the erase head side as compared with the magnetic reluctance of the read/write head side is provided at the coupling portion of the erase core and the centre core. One example of the means is that as illustrated in Figure 9 the coupling portion of the erase core to the centre core (or the coupling portion of the centre core to the erase core) is roughened. With this arrangement, the reproduction efficiency of the erase head can be reduced to thereby prevent the signal reproduced by the erase head from being leaked into the read/write head.
Still further, such a means can also be realised with the contact area S5 of the coupling portion of the erase core 5 and the centre core 2 being arranged to be smaller than the contact area S6 of the coupling portion of the read/write core 1 and the centre core 2 as illustrated in Figure 10.
According to the embodiments as described above, the magnetic head is provided with the back core coupled to the read/write core, centre core and erase core, and the read/write head with a closed magnetic circuit comprising the read/write core, centre core and back core is constructionally integrated with the erase head with a closed magnetic circuit comprising the erase core, centre core and back core. Since the erase-head side magnetic reluctance of the back core is arranged to be greater than the read/write-head side magnetic reluctance thereof, the magnetic flux to be drawn by the erase gap can be reduced so as to prevent the leakage into the read/write head, thereby making possible to obtain a reproduced signal with a high reliability.
This application describes matter described in co-pending Application No 91 03010.6, from which this application was divided.
Claims (14)
1. A magnetic head comprising a read/write core made of a magnetic material, a centre core made of a magnetic material and coupled to said read/write core so as to form a read/write gap therebetween on a surface over which a recording medium is to slide, an erase core made of a magnetic material and coupled to said centre core so as to form an erase gap therebetween on said surface, and a back core made of a magnetic material and coupled to said read/write core, said centre core and said erase core so as to form a closed magnetic circuit, wherein a crosssectional area transverse to the magnetic flux direction of a portion or all of the core forming the erase-head side magnetic circuit is smaller than a cross-sectional area of the core forming the read/write-head side magnetic circuit.
2. A magnetic head as claimed in claim 1 wherein said erase core and said centre core are coupled to each other by contact surfaces at least one of which is roughened to reduce the area of contact to provide a reduced cross-section of the magnetic circuit.
3. A magnetic head as claimed in claim 2, wherein a portion of or all of a surface of the erase-head side back core is machined to be rougher than a surface of the read/write core.
4. A magnetic head as claimed in claim 2, wherein the portion of said erase core in contact with said back core is machined to be rougher than the coupling portion of said read/write core to said back core.
5. A magnetic head as claimed in claim 1, wherein the back core on the erase head side has transverse slots to reduce the cross-sectional area of the magnetic circuit.
6. A magnetic head as claimed in claim 1, wherein the contact area of the back core and erase core is arranged to be smaller than the contact area of the back core and said read/write core.
7. A magnetic head according to claim 2 wherein the read/write and erase cores are C-shaped to include the back core and the contacting portion of said erase core and said centre core is machined to be rougher than the contacting portion of said read/write core and said centre core.
8. A magnetic head according to claim 1 wherein the read/write core and erase core are C-shaped to include the back core and the contact area of the erase core and said centre core is arranged to be smaller than the contact area of the read/write core and said centre core.
9. A magnetic head according to claim 1 wherein a spacer made of a non-magnetic material is provided in said back core so as to separate said erase head from said read/write head, said spacer being shifted to the erase head side with respect to the centre of said centre core.
10. A magnetic head according to claim 1 wherein the back core has a cross-section which reduces towards the erase head side.
11. A magnetic head according to claim 1 wherein the back core comprises two parts, one part forming part of both the read/write and erase magnetic circuits and the other part forming part of only the read/write magnetic circuit to provide a reduced reluctance therein.
12. A magnetic head according to claim 1 wherein the back core comprises two parallel elements both extending from the read/write core to the erase core via the centre core, the first element being of larger crosssectional area than the second, the first element including a transverse non-magnetic spacer adjacent the erase side of the centre core and the second element including a non-magnetic transverse spacer adjacent the read/write side of the centre core.
13. A magnetic head constructed and arranged to operate substantially as hereinbefore described with reference to Figures 1 to 10 of the accompanying drawings.
14. Magnetic recording/reproducing apparatus including a magnetic head according to any one of the preceding claims.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3367890A JPH03238608A (en) | 1990-02-16 | 1990-02-16 | Magnetic head |
| JP3367790A JPH03238607A (en) | 1990-02-16 | 1990-02-16 | Magnetic head |
| JP4788190A JPH03250410A (en) | 1990-02-28 | 1990-02-28 | Magnetic head |
| JP7471490 | 1990-03-23 | ||
| JP18452190A JPH03278305A (en) | 1990-03-23 | 1990-07-10 | Magnetic head |
| GB9103010A GB2242774B (en) | 1990-02-16 | 1991-02-13 | Magnetic head |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9402110D0 GB9402110D0 (en) | 1994-03-30 |
| GB2274018A true GB2274018A (en) | 1994-07-06 |
| GB2274018B GB2274018B (en) | 1994-09-21 |
Family
ID=27547126
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9402110A Expired - Fee Related GB2274018B (en) | 1990-02-16 | 1994-02-03 | Magnetic head |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2274018B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2009483A (en) * | 1977-12-05 | 1979-06-13 | Ibm | Magnetic erase head and method of producing same |
| GB1565301A (en) * | 1977-01-20 | 1980-04-16 | Data Recording Instr Co | Magnetic materials |
| GB2099204A (en) * | 1981-05-18 | 1982-12-01 | Tokyo Shibaura Electric Co | Combination magnetic head |
| US4768120A (en) * | 1986-09-08 | 1988-08-30 | Alps Electric Co., Ltd. | Complex magnetic head having non-magnetic center core |
-
1994
- 1994-02-03 GB GB9402110A patent/GB2274018B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1565301A (en) * | 1977-01-20 | 1980-04-16 | Data Recording Instr Co | Magnetic materials |
| GB2009483A (en) * | 1977-12-05 | 1979-06-13 | Ibm | Magnetic erase head and method of producing same |
| GB2099204A (en) * | 1981-05-18 | 1982-12-01 | Tokyo Shibaura Electric Co | Combination magnetic head |
| US4768120A (en) * | 1986-09-08 | 1988-08-30 | Alps Electric Co., Ltd. | Complex magnetic head having non-magnetic center core |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2274018B (en) | 1994-09-21 |
| GB9402110D0 (en) | 1994-03-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3551099B2 (en) | Thin-film magnetic head for magnetic tape device | |
| US4672494A (en) | Magnetic head for effecting perpendicular magnetic recording | |
| US5450264A (en) | Magnetic head | |
| US5276578A (en) | Magnetic head having a pair of front core assemblies | |
| JPH0366010A (en) | Magnetic head | |
| US4750071A (en) | Magnetic head assembly including a pair of heads disposed in the vicinity of each other | |
| GB2274018A (en) | Magnetic head | |
| US5479309A (en) | Magnetic head having spacer assembly with laminate of magnetic and non-magnetic material | |
| KR900007494B1 (en) | Complex magnetic head | |
| JP2565487B2 (en) | Composite magnetic head | |
| JPS61168117A (en) | Magnetic head | |
| JP2973012B2 (en) | Magnetic head | |
| JP3155781B2 (en) | Magnetic head and method of manufacturing the same | |
| JPH11120508A (en) | Magnetic head device | |
| KR890006297Y1 (en) | Magnetic head | |
| JP2778224B2 (en) | Magnetic head | |
| JP2847895B2 (en) | Magnetic head | |
| JPH05205218A (en) | Magnetic head | |
| JPS6040511A (en) | Vertical recording magnetic head | |
| JPH03250410A (en) | Magnetic head | |
| JPH01158608A (en) | Floating-type magnetic head | |
| JPS6284412A (en) | Magnetic head | |
| JPH05143928A (en) | Magnetic head | |
| JPS6247811A (en) | Magnetic head | |
| JPH03224112A (en) | Magnetic head |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 746 | Register noted 'licences of right' (sect. 46/1977) |
Effective date: 19960611 |
|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20080213 |