US5123933A — Method of producing magnetic disk

Claim 1

Independent Claim 55 words

A method of lapping a body to be lapped, comprising the steps of preparing a lapping member having a substrate and an abrasive layer formed on said substrate which abrasive layer includes at least two kinds of abrasive material different from each other in hardness, and lapping said body by use of said lapping member.

Claim 2

Independent Claim 55 words

A method of lapping a body to be lapped, comprising the steps of preparing a lapping member having a substrate and an abrasive layer formed on said substrate which abrasive layer includes at least two kinds of abrasive material different from each other in hardness, and lapping said body by use of said lapping member.

Claim 3

Dependent Claim 20 words

A method of lapping according to claim 1, wherein said lapping member is a lapping tape having a flexible substrate.

Claim 4

Dependent Claim 31 words

A method of lapping according to claim 1 or 2, wherein said abrasive materials include diamond and one kind selected from the group consisting of Al 2 O 3 and SiC.

Claim 5

Dependent Claim 50 words

A method of lapping according to claim 3, wherein the content of said diamond is not more than about 10 wt %, the content of said one kind selected from the group consisting of Al 2 O 3 and SiC being in a range of about 40% to about 89%.

Claim 6

Dependent Claim 28 words

A method of lapping according to claim 4, wherein said abrasive materials exist in a form of clusters in the abrasive layer, recesses being formed between the clusters.

Claim 7

Independent Claim 26 words

A method of lapping according to claims 1 or 2, wherein the abrasive materials include diamond and a substance having a hardness lower than the diamond.

Claim 8

Independent Claim 71 words

A method of lapping a body to be lapped, comprising the steps of preparing a lapping tape including a first abrasive material having a hardness not less than that of a hardest material constituting a surface portion of said body and a second abrasive material having a hardness lower than that of the hardest material constituting said surface portion of said body, and lapping said body by use of said tape.

Claim 9

Independent Claim 71 words

A method of lapping a body to be lapped, comprising the steps of preparing a lapping tape including a first abrasive material having a hardness not less than that of a hardest material constituting a surface portion of said body and a second abrasive material having a hardness lower than that of the hardest material constituting said surface portion of said body, and lapping said body by use of said tape.

Claim 10

Independent Claim 55 words

A method of lapping a body to be lapped, comprising the steps of preparing a lapping tape including a first abrasive material having hardness not less than that of a hardest material constituting a surface portion of said body and a second abrasive material having a hardness lower than that of said first abrasive material.

Claim 11

Independent Claim 55 words

A method of lapping a body to be lapped, comprising the steps of preparing a lapping tape including a first abrasive material having hardness not less than that of a hardest material constituting a surface portion of said body and a second abrasive material having a hardness lower than that of said first abrasive material.

Claim 12

Dependent Claim 58 words

A method of lapping according to claim 7 or 8, wherein said body to be lapped is a magnetic disk having a magnetic layer, said method further comprising the steps of rotating the magnetic disk, contacting the lapping tape with the surface of the rotating disk, and moving the lapping tape in contact with the rotating magnetic disk.

Claim 13

Independent Claim 109 words

A method comprising the steps of: preparing a lapping tape having an abrasive material layer provided with abrasive material clusters and chip pockets having an area of about 15-about 30% of entire surface of said layer formed between adjacent two clusters, each of said clusters having abrasive material of Al 2 O 3 or SiC and abrasive material of diamond, and binder resin said abrasive material layer comprising about 40 to about 89% by weight Al 2 O 3 of SiC abrasive material, and less than about 10% be weight diamond abrasive material, and lapping the surface of said magnetic disk medium by using the thus prepared lapping tape.

Claim 14

Independent Claim 109 words

A method comprising the steps of: preparing a lapping tape having an abrasive material layer provided with abrasive material clusters and chip pockets having an area of about 15-about 30% of entire surface of said layer formed between adjacent two clusters, each of said clusters having abrasive material of Al 2 O 3 or SiC and abrasive material of diamond, and binder resin said abrasive material layer comprising about 40 to about 89% by weight Al 2 O 3 of SiC abrasive material, and less than about 10% be weight diamond abrasive material, and lapping the surface of said magnetic disk medium by using the thus prepared lapping tape.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-06-23	1995-12-23	1996-06-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-06-23	1999-12-23	2000-06-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-06-23	2003-12-23	2004-06-23	$7700.00	Window Closed / Lapsed

Method of producing magnetic disk

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