Patent US4338367A successfully refreshed from Google Patents.
US4338367A
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Magnetic recording tape
Assignee: TDK Corp
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Filing: 1980-09-15
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Granted: 1982-07-06
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Expires: 2000-09-15
Abstract
Abstract A magnetic recording tape comprises a polyethyleneterephthalate base film coated with a magnetic layer which has an index H given by the equation: 1.5>19.00-0.406 d.sub.B -0.016 H-0.553 d.sub.T d.sub.T ≦18(μm) wherein the reference d T (μm) designates a total thickness of the magnetic recording tape; d B (μm) designates a thickness of the base film and H designates a sum of numbers of interference rings (H 1 , H 2 , H 3 . . . )per 1 mm 2 .
Inventors
- 👤 Yoshio Kawakami
- 👤 Yoneo Matsuzawa
- 👤 Norifumi Kajimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:16
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/269; Y10T428/31
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
90 words
A magnetic recording tape, which comprises: a polyethylene terephthalate base film coated with magnetic particles in a binder in which said base film has an index given by the expression 1.5>19.00-0.406d.sub.B -0.016H-0.553d.sub.T d.sub.T ≦18(μm) wherein d T (μm) designates the total thickness of the magnetic recording tape, d B (μm) designates the thickness of the base film and H designates the sum of numbers of interference rings (H 1 , H 2 , H 3 . . . ) per 1 mm 2 on the surface of the base film.
Claim 2
Dependent Claim
90 words
A magnetic recording tape, which comprises: a polyethylene terephthalate base film coated with magnetic particles in a binder in which said base film has an index given by the expression 1.5>19.00-0.406d.sub.B -0.016H-0.553d.sub.T d.sub.T ≦18(μm) wherein d T (μm) designates the total thickness of the magnetic recording tape, d B (μm) designates the thickness of the base film and H designates the sum of numbers of interference rings (H 1 , H 2 , H 3 . . . ) per 1 mm 2 on the surface of the base film.
Claim 3
Dependent Claim
20 words
The magnetic recording tape of claim 1, wherein the thickness of the magnetic layer ranges from 1.56 to 6.03 μm.
Claim 4
Dependent Claim
23 words
The magnetic recording tape of claim 1, wherein the magnetic particles of said magnetic layer are Co doped γ-Fe 2 O 3 .
Claim 5
Dependent Claim
52 words
The magnetic recording tape of claim 1, wherein said polyethyleneterephthalate base film has a surface roughness characterized by the values for H 1 to H 4 as follows: H 1 0.27 to 0.53 μm H 2 0.54 to 0.80 μm H 3 0.81 to 1.07 μm H 4 1.07 to 1.34 μm
Claim 6
Dependent Claim
17 words
The magnetic recording tape of claim 1, which has an output reduction of no more than 2.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-05 | 1986-01-04 | 1986-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-05 | 1990-01-04 | 1990-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-05 | 1994-01-04 | 1994-07-06 | $7700.00 | Window Closed / Lapsed |