US4746558A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
•
Filing: 1986-03-19
•
Granted: 1988-05-24
•
Expires: 2006-03-19
Abstract
Abstract A magnetic recording medium comprising a non-magnetic substrate and a coating type magnetic recording layer formed on the substrate, wherein barium ferrite magnetic powder is perpendicularly oriented, characterized in that an undercoating layer comprising a radiation curable binder and carbon black, is provided beneath the magnetic recording layer.
Inventors
- 👤 Toru Shimozawa
- 👤 Kazunori Tamazaki
- 👤 Masaharu Nishimatsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:57
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/733; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/25
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
102 words
A magnetic recording medium comprising a non-magnetic substrate and a magnetic recording layer formed on the substrate consisting essentially of a single layer of barium ferrite magnetic powder, perpendicularly oriented, dispersed in a resin binder, wherein said recording layer contains carbon black, has a surface roughness of at most 0.08μ as measured by a 20 point average method and wherein said barium ferrite magnetic powder has a partilce size of at most 0.02μ and an aspect ratio of at least 6, characterized in that an undercoating layer comprising a radiation curable binder and carbon black, is provided beneath the magnetic recording layer.
Claim 2
Dependent Claim
102 words
A magnetic recording medium comprising a non-magnetic substrate and a magnetic recording layer formed on the substrate consisting essentially of a single layer of barium ferrite magnetic powder, perpendicularly oriented, dispersed in a resin binder, wherein said recording layer contains carbon black, has a surface roughness of at most 0.08μ as measured by a 20 point average method and wherein said barium ferrite magnetic powder has a partilce size of at most 0.02μ and an aspect ratio of at least 6, characterized in that an undercoating layer comprising a radiation curable binder and carbon black, is provided beneath the magnetic recording layer.
Claim 3
Dependent Claim
37 words
The magnetic recording medium according to claim 1, wherein carbon black in the undercoating layer is used in an amount of from 5 to 200 parts by weight relative to 100 parts by weight of the binder.
Claim 4
Dependent Claim
18 words
The magnetic recording medium according to claim 1, wherein the carbon black in the magnetic layer is graphitized.
References Cited (Backward Citations)
US4183976A
Cited
US4442159A
Cited
US4511617A
Cited
US4596747A
Cited
US4547419A
Cited
US4585697A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-24 | 1991-11-23 | 1992-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-24 | 1995-11-23 | 1996-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-24 | 1999-11-23 | 2000-05-24 | $7700.00 | Window Closed / Lapsed |