IP Library Patent Application 11155616
Patent Application
App. No. 11/155,616

Magnetic recording medium

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Quick Facts
Patent No.
US None
App. No.
11/155,616
Abstract

A magnetic recording medium comprising: a non-magnetic support; and a magnetic layer comprising a hexagonal ferrite and a binder, wherein the magnetic layer has a thickness of from 30 to 100 nm, a coercive force of from 3,000 to 4,200 Oe and a magnetization reversal volume of from 3×10 −18 to 10×10 −18 mL, and the hexagonal ferrite has a tabular ratio of from 2 to 3.

Claims (14)

1 . A magnetic recording medium comprising: a non-magnetic support; and a magnetic layer comprising a hexagonal ferrite and a binder, wherein the magnetic layer has a thickness of from 30 to 100 nm, a coercive force of from 3,000 to 4,200 Oe and a magnetization reversal volume of from 1×10 −18 to 10×10 −18 mL, and the hexagonal ferrite has a tabular ratio of from 2 to 3.

2 . The magnetic recording medium according to claim 1 , which further comprises a non-magnetic layer between the non-magnetic support and the magnetic layer, the non-magnetic layer comprising non-magnetic powder and a binder.

3 . The magnetic recording medium according to claim 2 , wherein the non-magnetic layer has a thickness of from 0.5 to 2.0 μm.

4 . The magnetic recording medium according to claim 2 , wherein the non-magnetic layer has a thickness of from 0.8 to 1.5 μm.

5 . The magnetic recording medium according to claim 2 , wherein the non-magnetic layer has a thickness of from 0.8 to 1.2 μm.

6 . The magnetic recording medium according to claim 2 , wherein the non-magnetic powder has a mean particle size of from 5 nm to 2 μm.

7 . The magnetic recording medium according to claim 2 , wherein the non-magnetic powder has a mean particle size of from 10 nm to 200 nm.

8 . The magnetic recording medium according to claim 2 , wherein the non-magnetic layer further comprises carbon black.

9 . The magnetic recording medium according to claim 1 , wherein the magnetic layer has a thickness of from 40 to 80 nm.

10 . The magnetic recording medium according to claim 1 , wherein the magnetic layer has a coercive force of from 3,200 to 4,000 Oe.

11 . The magnetic recording medium according to claim 1 , wherein the magnetic layer has a magnetization reversal volume of from 3×10 −18 to 7×10 −18 mL.

12 . The magnetic recording medium according to claim 1 , wherein the hexagonal ferrite has a tabular ratio of from 2 to 2.5.

13 . The magnetic recording medium according to claim 1 , wherein the hexagonal ferrite contains Ba and Fe at a ratio of Ba to Fe of from 0.075 to 0.085.

14 . The magnetic recording medium according to claim 1 , wherein the magnetic layer further comprises carbon black.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 15, 2007
From: FUJIFILM HOLDINGS CORPORATION (FORMERLY FUJI PHOTO FILM CO., LTD.)
To: FUJIFILM CORPORATION
Reel/Frame 018904/0001 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 20, 2005
From: YAMAZAKI, NOBUO; TAKAHASHI, MASATOSHI
To: FUJI PHOTO FILM CO., LTD.
Reel/Frame 016714/0179 →