US4828899A — Magnetic recording medium and recording/reproduci…

Claim 1

Independent Claim 162 words

A magnetic recording medium comprising: a flexible substraste having opposed major surfaces, a ferromagnetic metal thin film layer on one surface of the substrate primarily comprising cobalt, an organic topcoat layer on the surface of the metal thin film layer, and the magnetic recording medium being used in combination with a magnetic head having a gap, the improvement wherein said organic topcoat layer contains a radiationcurable compund having a molecular weight of less than 2,000, an anti-oxidant, and a lubricant, said metal thin film layer contains oxygen, and the medium has protrusions on its surface at an average density of at least 10 5 /a 2 per square millimeter of the surface, where a is the distance of the magnetic head gap as expressed in μm and is from 0.1 to 0.5 μm, said protrusions corresponding to the submicron paticles of a size of 30 to 300 Å within the medium, and said protrusions having a height of 30 to 300 Å.

Claim 2

Dependent Claim 162 words

A magnetic recording medium comprising: a flexible substraste having opposed major surfaces, a ferromagnetic metal thin film layer on one surface of the substrate primarily comprising cobalt, an organic topcoat layer on the surface of the metal thin film layer, and the magnetic recording medium being used in combination with a magnetic head having a gap, the improvement wherein said organic topcoat layer contains a radiationcurable compund having a molecular weight of less than 2,000, an anti-oxidant, and a lubricant, said metal thin film layer contains oxygen, and the medium has protrusions on its surface at an average density of at least 10 5 /a 2 per square millimeter of the surface, where a is the distance of the magnetic head gap as expressed in μm and is from 0.1 to 0.5 μm, said protrusions corresponding to the submicron paticles of a size of 30 to 300 Å within the medium, and said protrusions having a height of 30 to 300 Å.

Claim 3

Dependent Claim 42 words

A magnetic recording medium according to claim 1 wherein said flexible substrate is comprised of a high polymer, and the protrusions conform to submicron particles having a size of 30 to 300 Å which are placed on one surface of the substrate.

Claim 4

Dependent Claim 26 words

A magnetic recoridng medium according to claim 1 wherein said ferromagnetic metal thin film layer at the surface s covered with a ferromagnetic metal oxide coating.

Claim 5

Dependent Claim 22 words

A magnetic recording medium according to claim 1 wherein the anti-oxidant in the topcoat layer is comprised of a radiation curable anti-oxidant.

Claim 6

Dependent Claim 23 words

A magnetic reocridng medium according to claim 1 wherein the lubricant in the top coat layer is comprised of a radiation curable lubricant.

Claim 7

Dependent Claim 20 words

A magnetic recording medium according to claim 1 wherein said topcoat layer has a thickness of 10 to 100 Å

Claim 8

Independent Claim 160 words

A method for conducting recording/reporducing operation on a magnetic recording medium comprising a flexible substrate havig opposed major surfaes, a ferromagnetic metal thin film layer on one surface of the substrate principally comprsiing cobalt, and an organic topcoat layer on the surface of the metal thin film layer, by passing the medium across a magnetic head having a gap, the improvement wherein said organic topcoat layer contains a radiation curable compound having a molecular weight of less than 2,000 an anti-oxidant, and a lubricant, said metal thin film layer contains oxygen, and the medium has in average at least 10 5 /a 2 protrusions per square millimeter of the surface, where a is the distance of the magnetic head gas as expressed in μm and is from 0.1 to 0 5 μm, said protrusions corresponding to submicron particles of a size of 30 to 300 Å within the medium, and said protrusions having a height of 30 to 300 Å.

Claim 9

Independent Claim 160 words

A method for conducting recording/reporducing operation on a magnetic recording medium comprising a flexible substrate havig opposed major surfaes, a ferromagnetic metal thin film layer on one surface of the substrate principally comprsiing cobalt, and an organic topcoat layer on the surface of the metal thin film layer, by passing the medium across a magnetic head having a gap, the improvement wherein said organic topcoat layer contains a radiation curable compound having a molecular weight of less than 2,000 an anti-oxidant, and a lubricant, said metal thin film layer contains oxygen, and the medium has in average at least 10 5 /a 2 protrusions per square millimeter of the surface, where a is the distance of the magnetic head gas as expressed in μm and is from 0.1 to 0 5 μm, said protrusions corresponding to submicron particles of a size of 30 to 300 Å within the medium, and said protrusions having a height of 30 to 300 Å.

Claim 10

Dependent Claim 28 words

A magnetic recording/reproducing method according to claim 7 wherein at least an edge portion of the magnetic head including the gap is formed of a ferromagnetic metal material.

Claim 11

Dependent Claim 20 words

A magnetic recording/reproducing method according to claim 7 wherein the ferromagnetic metal material is a magnetic amorphous cobalt base alloy.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-05-08	1992-11-07	1993-05-09	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-05-08	1996-11-07	1997-05-09	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-05-08	2000-11-07	2001-05-09	$7700.00	Window Closed / Lapsed

Magnetic recording medium and recording/reproducing method thereof

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