Patent US4778714A successfully refreshed from Google Patents.
US4778714A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nonabrasive magnetic recording tape
Assignee: 3M Co
•
Filing: 1985-10-11
•
Granted: 1988-10-18
•
Expires: 2005-10-11
Abstract
Abstract Magnetic recording tape is suitable for data recording mechanisms equipped with brass or other soft heads when its magnetizable layer is based on ferromagnetic iron oxide particles and contains titanium dioxide or other soft head cleaning agent which has a hardness approximating or slightly exceeding that of the iron oxide. The magnetizable layer preferably is free from, but may also contain unusually small amounts of hard head cleaning agent such as alumina.
Inventors
- 👤 Karen M. Woolley
- 👤 Chong-Yong Kim
- 👤 Arthur J. Ellsworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:28
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/24983; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/258; Y10T428/259; Y10T428/29; Y10T428/2982
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
108 words
Magnetic recording tape suitable for data recording mechanisms equipped with soft heads, said tape having a magnetizable layer comprising ferromagnetic iron oxide particles dispersed in binder, which layer includes, based on the weight of the iron oxide particles, from 0.5 to 3.0% of soft head cleaning agent having a Knoop hardness of from 600 to 1200 while being substantially free from any hard head cleaning agent, and wherein any head cleaning agent is substantially free from particles exceeding 2 micrometers in diameter and the hardness of said ferromagnetic iron oxide particles is approximately the same as or slightly less than the hardness of said soft head cleaning agent.
Claim 2
Dependent Claim
108 words
Magnetic recording tape suitable for data recording mechanisms equipped with soft heads, said tape having a magnetizable layer comprising ferromagnetic iron oxide particles dispersed in binder, which layer includes, based on the weight of the iron oxide particles, from 0.5 to 3.0% of soft head cleaning agent having a Knoop hardness of from 600 to 1200 while being substantially free from any hard head cleaning agent, and wherein any head cleaning agent is substantially free from particles exceeding 2 micrometers in diameter and the hardness of said ferromagnetic iron oxide particles is approximately the same as or slightly less than the hardness of said soft head cleaning agent.
Claim 3
Dependent Claim
22 words
Magnetic recording tape as defined in claim 1 wherein the Knoops hardness of the soft head cleaning agent is less than 800.
Claim 4
Dependent Claim
17 words
Magnetic recording tape as defined in claim 2 wherein the soft head cleaning agent is titanium dioxide.
Claim 5
Dependent Claim
19 words
A data recording mechanism equipped with a soft head and a magnetic recording tape as defined in claim 2.
Claim 6
Dependent Claim
15 words
A belt-driven data cartridge loaded with a magnetic recording tape as defined in claim 2.
Claim 7
Dependent Claim
99 words
Method of making a magnetic recording tape which is suitable for data recording mechanisms equipped with soft heads, said method comprising the steps of dispersing into a binder ferromagnetic iron oxide particles and from 0.5 to 3% by weight of soft head cleaning agent having a Knoop hardness of between 600 and 1200 while keeping the dispersion substantially free from any hard head cleaning agent wherein the hardness of said ferromagnetic iron oxide particles is approximately the same as or slightly less than the hardness of said soft head cleaning agent and coating the dispersion onto a nonmagnetic backing.
Claim 8
Dependent Claim
99 words
Method of making a magnetic recording tape which is suitable for data recording mechanisms equipped with soft heads, said method comprising the steps of dispersing into a binder ferromagnetic iron oxide particles and from 0.5 to 3% by weight of soft head cleaning agent having a Knoop hardness of between 600 and 1200 while keeping the dispersion substantially free from any hard head cleaning agent wherein the hardness of said ferromagnetic iron oxide particles is approximately the same as or slightly less than the hardness of said soft head cleaning agent and coating the dispersion onto a nonmagnetic backing.
Claim 9
Dependent Claim
20 words
Method as defined in claim 6 wherein the Knoops hardness of the soft head cleaning agent is less than 800.
Claim 10
Dependent Claim
15 words
Method as defined in claim 7 wherein the soft head cleaning agent is titanium dioxide.
References Cited (Backward Citations)
US3630910A
Cited
DE1804393A1
Cited
DE1953459A1
Cited
US3929658A
Cited
US4275115A
Cited
US4399189A
Cited
US4420408A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-10-18 | 1992-04-18 | 1992-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-18 | 1996-04-18 | 1996-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-18 | 2000-04-18 | 2000-10-18 | $7700.00 | Window Closed / Lapsed |