Patent US4499121A successfully refreshed from Google Patents.
US4499121A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing a magnetic recording medium with a calendering treatment
Assignee: Fujifilm Holdings Corp
•
Filing: 1983-05-04
•
Granted: 1985-02-12
•
Expires: 2003-05-04
Abstract
Abstract A method for producing a magnetic recording medium is disclosed. The method involves providing a ferromagnetic coating layer on a non-magnetic support base to produce a coated base. The coated base is then subjected to an atmosphere having a RH of 60% or more, prior to or during a subsequent calendering treatment. The recording medium produced has excellent surface smoothness and improved electromagnetic properties. The method is advantageous in that a substantially long period of time may pass between the coating of the ferromagnetic layer on the support and the calendering treatment without having undesirable effects on the magnetic recording medium produced.
Inventors
- 👤 Nobutaka Yamaguchi
- 👤 Masaaki Fujiyama
- 👤 Sugihiko Tada
- 👤 Eiichi Tadokoro
- 👤 Katsumi Ryoke
- 👤 Masahiro Utsumi
- 👤 Masami Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:15
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
57 words
A method for producing a magnetic recording medium comprising the steps of: (A) providing a ferromagnetic coating layer on a non-magnetic support base to provide a coated base; (B) subjecting the coated base to an atmosphere having an RH of not less than 60% prior to step (C); and (C) subjecting the coated base to calendaring treatment.
Claim 2
Independent Claim
57 words
A method for producing a magnetic recording medium comprising the steps of: (A) providing a ferromagnetic coating layer on a non-magnetic support base to provide a coated base; (B) subjecting the coated base to an atmosphere having an RH of not less than 60% prior to step (C); and (C) subjecting the coated base to calendaring treatment.
Claim 3
Dependent Claim
24 words
A method for producing a magnetic recording medium as claimed in claim 1, wherein the atmosphere has a RH of not less than 70%.
Claim 4
Dependent Claim
24 words
A method for producing a magnetic recording medium as claimed in claim 2, wherein the atmosphere has a RH of not less than 85%.
Claim 5
Dependent Claim
31 words
A method for producing a magnetic recording medium as claimed in claim 1, wherein the calendering treatment is carried out at a temperature within the range of 5° to 40° C.
Claim 6
Dependent Claim
31 words
A method for producing a magnetic recording medium as claimed in claim 4, wherein the calendering treatment is carried out at a temperature within the range of 10° to 35° C.
Claim 7
Dependent Claim
46 words
A method for producing a magnetic recording medium as claimed in claim 1, wherein the calendering is carried out using a metal role having a temperature within the range of 30° to 120° C. using a linear pressure within the range of 50 to 500 Kg/cm.
References Cited (Backward Citations)
US3398011A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-02-12 | 1988-08-13 | 1989-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-12 | 1992-08-13 | 1993-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-12 | 1996-08-13 | 1997-02-12 | $7700.00 | Window Closed / Lapsed |