WO1983001145A1 - Magnetic recording medium - Google Patents
Magnetic recording medium Download PDFInfo
- Publication number
- WO1983001145A1 WO1983001145A1 PCT/JP1982/000390 JP8200390W WO8301145A1 WO 1983001145 A1 WO1983001145 A1 WO 1983001145A1 JP 8200390 W JP8200390 W JP 8200390W WO 8301145 A1 WO8301145 A1 WO 8301145A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- magnetic
- recording medium
- layer
- magnetic recording
- powder
- Prior art date
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
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
- G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
- G11B5/716—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by two or more magnetic layers
Definitions
- the present invention relates to a magnetic recording medium, and particularly to a magnetic recording medium having two magnetic layers.
- the inventor of the present invention has found that, by conducting various experiments and studies, in a magnetic recording medium, when the iron oxide magnetic powder having a large specific surface area is distributed on the surface of the magnetic layer, the bias noise is reduced, and the inside of the magnetic layer ( That is, it has been found that the reproduction output is increased over the entire band when the iron oxide-based magnetic powder having a small specific surface area is distributed in the lower layer below the middle in the thickness direction).
- the present invention forms the magnetic layer of the magnetic recording medium as a two-layer structure made of iron oxide-based magnetic powder, and the specific surface area and the resistance of each magnetic powder of the upper and lower magnetic layers.
- the magnetic force Hc , the residual magnetic flux density Br, the thickness of the layer, etc. are each selected and configured to reduce the bias noise while maintaining a high reproduction output over the entire band.
- OMPI It is possible to provide a magnetic recording medium that is superior to a magnetic recording medium (for example, a metal tape).
- FIG. 1 is an enlarged sectional view of a conventional magnetic recording medium
- FIG. 2 is an enlarged sectional view of a magnetic recording medium according to the present invention
- FIGS. FIGS. 4A and 4B are tables showing the characteristics of each embodiment of the double-layer magnetic recording medium according to the present invention.
- the specific surface area of the magnetic powder is the specific surface area determined by the BET method.
- Magnetic coating (A) 4 parts by weight lecithin 700 parts by weight methyl ketone 700 parts by weight
- a magnetic paint was obtained by the same process as in the magnetic coating (A) of the first practical example. This is a magnetic paint
- a magnetic coating was obtained by the same process as the magnetic coating (A) in the first example. This is a magnetic paint
- the Fe 2 0 3 magnetic powder - r of the magnetic coating composition (C) of the third embodiment The specific surface area 20m 2 "g, 7 ⁇ coercivity 420 Oe - substituting the Fe 2 0 3 magnetic resistance powder (others in the same) to the same process as the magnetic paint (A) of the first embodiment A magnetic paint was obtained, which was designated as a magnetic paint (D).
- the 3 r of the magnetic coating family (C) of Example - Fe 2 0 3 magnetic powder the specific surface area of 30 m 2 Zg, coercive force 320 Oe, 420 Oe and
- Pe 2 0 3 magnetic powder the specific surface area 40 m 2 Zg, Ryo coercivity 320 Oe, 420 Oe and 520 Oe - - r magnetic coating composition (A) of the first embodiment by replacing the Fe 2 0 3 magnetic powder (other A magnetic paint was obtained by the same process as the magnetic paint (A).
- R of the magnetic coating composition (C) of the third embodiment - Fe 2 0 3 magnetic powder the specific surface area of 30 m 2 Zg, coercive force 520 Oe,. 720 Oe and
- Co-coated r of 920 Oe - substituting the Fe 2 0 3 magnetic powder was obtained by Ri magnetic paint (others same as with) the magnetic coating family first embodiment (A) and the same process . These are designated as magnetic paints (K), (L) and (M), respectively.
- the 3 r magnetic coating composition (C) of Example - Fe 2 0 3 magnetic powder the specific surface area of 40 m 2 / g, coercive force 520 Oe, 720 Oe and
- PZB indicates the ratio of binder-B to magnetic powder P.
- each of the above magnetic paints (A) to (P) is used, and as shown in FIG. 1, a non-magnetic substrate (for example, a polyethylene telephthalate having a thickness of 12) is used.
- a non-magnetic substrate for example, a polyethylene telephthalate having a thickness of 12
- a magnetic coating is applied on top of the film, treated with magnetic field orientation, dried, and then treated with a super calender roll to form a single magnetic layer
- a magnetic recording medium (3) formed by forming (2) is created.
- a first magnetic layer (lower layer) (4) is formed in the same process as shown in FIG. 2 using the same magnetic paints (A :) to (P).
- the second magnetic layer (upper layer) (5) is formed in the same process as above to produce a two-layer magnetic recording medium (6) according to the present invention.
- FIGS. 3A and 3B show the characteristics (single-layer example (1) to ⁇ 5)) of the magnetic recording medium (3) with a single magnetic layer (2) made of each magnetic paint (A) to (P).
- FIGS. 7A and 7B show the characteristics (Examples (1) to 4) of the dual-layer magnetic recording medium (6) according to the present invention.
- the magnetic recording medium (magnetic tape) used for the measurement was an audio tape cut to a width of 1Z8 inch.
- the measuring method of each characteristic is as follows.
- Residual magnetic flux density Br is the residual magnetic flux density measured at an external magnetic field of 2000 Oe.
- the unit is Gauss (gau s s).
- coercivity H c is Ru coercivity der when measured at an external magnetic field 2000 Oe.
- the unit is el stead (Oe).
- the MOL maximum output level: playback output
- the latter is the maximum saturation output level of a 10 kHz signal.
- Bias noise is the noise when using the audibility correction filter-A (JIS).
- the unit is decibel (db).
- the tabular speed is 4.8 oni / m.
- the MOL (315 Hz, 10 kHz) and bias noise are shown as relative values (db) with reference to the single layer example (1) in Fig. 3A (0 db).
- the specific surface area of the magnetic powder of the upper second magnetic layer (5) is larger than that of the lower first magnetic layer (4).
- the double-layer magnetic recording medium (6) according to the present invention has a higher reproduction output over the entire lower and higher frequency bands than the conventional single-layer magnetic recording medium (3), Significant reduction of noise is recognized.
- the specific surface area of the iron oxide magnetic powder in the lower first magnetic layer (4) is in the range of about 20 m 2 Zg (18 to 25 m 2 Zg).
- the specific surface area of the iron oxide magnetic powder in the upper second magnetic layer (5) is more than 28 m 2 Zg, more preferably in the range of 28 to 45 m 2 / g. Does not reduce the bias noise.
- the coercive force H C i and the residual magnetic flux density of the first magnetic layer (4) are 250-400 El Steads and 1600-2000 Gauss force, respectively. If it is out of the range of ⁇ 2000 Gauss, the output in the low frequency range will decrease.
- the coercive force H C2 of the second magnetic layer (5) is preferably 250 to 500, preferably 250 to 500 when the iron oxide-based magnetic powder is used. Or: For iron oxide-based magnetic powder coated with F «e and Co compounds, 300 to 900 enolettes are preferred. Outside of this range, the high frequencies will not extend, and the recording bias and erasure will be restricted by the recording / reproducing device. The optimum recording bias is set according to the coercive force of the magnetic layer.
- the relationship between the coercive force H C 2 coercivity 1 and the second magnetic layer of the first magnetic layer (4) (5) is not to prefer the Hc i rather H C 2 0
- the thickness of the first magnetic layer (4) is preferably not less than 2.0 mm and not more than 6.0, more preferably not more than 2.0 #. Only the low-frequency reproduction output is too high, and the balance in the low-frequency region becomes poor. When this happens, the noise noise does not decrease, and when it is thicker than 2.0 ⁇ , the low-frequency reproduction output decreases.
- the first 0 PI is formed on the non-magnetic substrate (1) as shown in FIG.
- the first magnetic layer (4) has a specific surface area of 18 to 25 m 2 / g of iron oxide-based magnetic powder is applied, and the coercive force H C1 is set to 250 to 400 Jersted and the residual magnetic flux density Br is set to 1600 to 2000 gauth.
- 2-magnetic layer (5) a specific surface area Ru good to BET method 28 m or more on, rather then preferred Ri good is formed by coating the iron oxide-based magnetic powder 28 ⁇ 45 mg, its coercive force H C 2 is from 250 to 900 elsteads.
Landscapes
- Magnetic Record Carriers (AREA)
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19823249036 DE3249036T1 (de) | 1981-09-28 | 1982-09-27 | Magnetisches aufzeichnungsmedium |
GB08313548A GB2118070B (en) | 1981-09-28 | 1982-09-27 | Magnetic recording medium |
NL8220324A NL8220324A (nl) | 1981-09-28 | 1982-09-27 | Magnetisch registreermedium. |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP56/153299 | 1981-09-28 | ||
JP56153300A JPS5856230A (ja) | 1981-09-28 | 1981-09-28 | 磁気記録媒体 |
JP56153299A JPS5856229A (ja) | 1981-09-28 | 1981-09-28 | 磁気記録媒体 |
JP56/153300810928 | 1981-09-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1983001145A1 true WO1983001145A1 (en) | 1983-03-31 |
Family
ID=26481961
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1982/000390 WO1983001145A1 (en) | 1981-09-28 | 1982-09-27 | Magnetic recording medium |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0090053B1 (ja) |
GB (1) | GB2118070B (ja) |
NL (1) | NL8220324A (ja) |
WO (1) | WO1983001145A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4689263A (en) * | 1983-09-02 | 1987-08-25 | Tdk Corporation | Magnetic recording medium |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60124025A (ja) * | 1983-12-06 | 1985-07-02 | Fuji Photo Film Co Ltd | 磁気記録媒体 |
DE19714161A1 (de) * | 1997-04-05 | 1998-10-08 | Emtec Magnetics Gmbh | Magnetischer Aufzeichnungsträger |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5251908A (en) * | 1975-10-23 | 1977-04-26 | Fuji Photo Film Co Ltd | Magnetic recording tape |
JPS5228364B1 (ja) * | 1971-02-26 | 1977-07-26 | ||
JPS5421304A (en) * | 1977-07-18 | 1979-02-17 | Fuji Photo Film Co Ltd | Double layer magnetic recording tape |
JPS5448504A (en) * | 1977-09-21 | 1979-04-17 | Tdk Corp | Magnetic recording medium |
JPS5630608B2 (ja) * | 1973-08-27 | 1981-07-16 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE795896A (fr) * | 1972-02-24 | 1973-08-23 | Eastman Kodak Co | Materiau pour l'enregistrement magnetique a plusieurs couches et son procede de preparation |
GB1504293A (en) * | 1975-02-12 | 1978-03-15 | Emi Ltd | Method of forming magnetic media |
JPS58100B2 (ja) * | 1975-04-11 | 1983-01-05 | 富士写真フイルム株式会社 | ジキキロクタイ |
GB2042370B (en) * | 1980-02-06 | 1982-12-08 | Tdk Electronics Co Ltd | Magnetic recording medium |
-
1982
- 1982-09-27 NL NL8220324A patent/NL8220324A/nl not_active Application Discontinuation
- 1982-09-27 WO PCT/JP1982/000390 patent/WO1983001145A1/ja active IP Right Grant
- 1982-09-27 EP EP19820902835 patent/EP0090053B1/en not_active Expired
- 1982-09-27 GB GB08313548A patent/GB2118070B/en not_active Expired
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5228364B1 (ja) * | 1971-02-26 | 1977-07-26 | ||
JPS5630608B2 (ja) * | 1973-08-27 | 1981-07-16 | ||
JPS5251908A (en) * | 1975-10-23 | 1977-04-26 | Fuji Photo Film Co Ltd | Magnetic recording tape |
JPS5421304A (en) * | 1977-07-18 | 1979-02-17 | Fuji Photo Film Co Ltd | Double layer magnetic recording tape |
JPS5448504A (en) * | 1977-09-21 | 1979-04-17 | Tdk Corp | Magnetic recording medium |
Non-Patent Citations (1)
Title |
---|
See also references of EP0090053A4 * |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4689263A (en) * | 1983-09-02 | 1987-08-25 | Tdk Corporation | Magnetic recording medium |
Also Published As
Publication number | Publication date |
---|---|
GB2118070B (en) | 1985-08-14 |
GB2118070A (en) | 1983-10-26 |
EP0090053B1 (en) | 1987-06-24 |
GB8313548D0 (en) | 1983-06-22 |
NL8220324A (nl) | 1983-08-01 |
EP0090053A1 (en) | 1983-10-05 |
EP0090053A4 (en) | 1985-04-11 |
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