Patent US4338643A successfully refreshed from Google Patents.
US4338643A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording disc and method of making same
Assignee: Fujifilm Holdings Corp
•
Filing: 1980-04-08
•
Granted: 1982-07-06
•
Expires: 2000-04-08
Abstract
Abstract In a method of making a magnetic recording sheet, a magnetic material is applied on a web in a layer consisting of a number of contiguous first strip-like zones and second strip-like zones which are alternately arranged in parallel to each other. The ratio of the width of the first strip-like zone to that of the second strip-like zone is within a range of 1:3 to 3:1. In the first strip-like zones having a width of not more than 5 mm the magnetic particles are oriented in a first direction, and in the second strip-like zones magnetic particles are oriented in a second direction which is inclined with respect to the first direction at an angle from 60 DEG to 120 DEG . With this particular orientation of the magnetic particles in the magnetic layer when the magnetic layer is applied on a web, the orientation of the magnetic particles become almost random while the magnetic layer is hardened. The magnetic recording disc thus prepared has a very low output fluctuation and a higher output level.
Inventors
- 👤 Eiichi Tadokoro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 04:01
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/852; G11B5/62; G11B5/68; G11B5/70
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
176 words
A method of producing a magnetic recording disc comprising applying a magnetic layer containing magnetic particles on a support film base, orienting the magnetic particles in a number of first strip-like zones in a first direction and in a number of second strip-like zones in a second direction inclined with respect to the first direction at an angle of 60° to 120°, said first and second strip-like zones being alternately and contiguously arranged in parallel to each other, the width of each said first and second strip-like zones being not more than 5 mm and the ratio of the width of the first strip-like zone to that of the second strip-like zone being within the range of 1:3 to 3:1, solidifying the magnetic layer after the magnetic particles in said first strip-like zones, causing interaction along the boundaries between adjacent strip-like zones resulting in a random particle orientation and then stamping out a magnetic recording disc from the support film base, whereby positioning of a disc center hole is greatly fascilitated and the output is enhenced.
Claim 2
Independent Claim
176 words
A method of producing a magnetic recording disc comprising applying a magnetic layer containing magnetic particles on a support film base, orienting the magnetic particles in a number of first strip-like zones in a first direction and in a number of second strip-like zones in a second direction inclined with respect to the first direction at an angle of 60° to 120°, said first and second strip-like zones being alternately and contiguously arranged in parallel to each other, the width of each said first and second strip-like zones being not more than 5 mm and the ratio of the width of the first strip-like zone to that of the second strip-like zone being within the range of 1:3 to 3:1, solidifying the magnetic layer after the magnetic particles in said first strip-like zones, causing interaction along the boundaries between adjacent strip-like zones resulting in a random particle orientation and then stamping out a magnetic recording disc from the support film base, whereby positioning of a disc center hole is greatly fascilitated and the output is enhenced.
Claim 3
Dependent Claim
25 words
A method of producing a magnetic recording disc as defined in claim 1 wherein the width of each zone is not more than 3 mm.
Claim 4
Dependent Claim
30 words
A method of producing a magnetic recording disc as defined in claim 1 wherein said ratio of the widths of the zones is within the range of 1:2 to 2:1.
Claim 5
Dependent Claim
31 words
A method of producing a magnetic recording disc as defined in claim 1 wherein in said first strip-like zones the magnetic particles are oriented in the longitudinal direction of the zones.
Claim 6
Dependent Claim
34 words
A method of producing a magnetic recording disc as defined in claim 4 wherein said second strip-like zones the magnetic particles are oriented in the direction perpendicular to the longitudinal direction of the zones.
Claim 7
Dependent Claim
164 words
A magnetic recording disc comprising a circular support film base and a magnetic layer containing magnetic particles carried on a support film base wherein said magnetic layer includes a number of first strip-like zones in which the magnetic particles are oriented in a first direction and a number of second strip-like zones in which the magnetic particles are oriented in a second direction inclined with respect to the first direction at an angle of 60° to 120°, said first and second strip-like zones being alternately and contiguously arranged in parallel to each other, the width of each said first and second strip-like zone being not more than 5 mm and the ratio of the width of the first strip-like zone to that of the second strip-like zone being within the range of 1:3 to 3:1, the magentic particles at the boundaries formed between said first and second strip-like zones being randomly oriented with said particle orientation resulting in a disc exhibiting improved recording characteristics.
Claim 8
Dependent Claim
164 words
A magnetic recording disc comprising a circular support film base and a magnetic layer containing magnetic particles carried on a support film base wherein said magnetic layer includes a number of first strip-like zones in which the magnetic particles are oriented in a first direction and a number of second strip-like zones in which the magnetic particles are oriented in a second direction inclined with respect to the first direction at an angle of 60° to 120°, said first and second strip-like zones being alternately and contiguously arranged in parallel to each other, the width of each said first and second strip-like zone being not more than 5 mm and the ratio of the width of the first strip-like zone to that of the second strip-like zone being within the range of 1:3 to 3:1, the magentic particles at the boundaries formed between said first and second strip-like zones being randomly oriented with said particle orientation resulting in a disc exhibiting improved recording characteristics.
Claim 9
Dependent Claim
21 words
A magnetic recording disc as defined in claim 6 wherein the width of each zone is not more than 3 mm.
Claim 10
Dependent Claim
26 words
A magnetic recording disc as defined in claim 6 wherein said ratio of the widths of the zones is within the range of 1:2 to 2:1.
Claim 11
Dependent Claim
27 words
A magnetic recording disc as defined in claim 6 wherein in said first strip-like zones the magnetic particles are oriented in the longitudinal direction of the zones.
Claim 12
Dependent Claim
30 words
A magnetic recording disc as defined in claim 9 wherein said second strip-like zones the magnetic particles are oriented in the direction perpendicular to the longitudinal direction of the zones.
References Cited (Backward Citations)
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 |