Magnetic recording tape

• US 6,228,461 B1
• Filed: 03/01/1999
• Issued: 05/08/2001
• Est. Priority Date: 02/27/1998
• Status: Expired due to Fees

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Sueki, Minoru, Takahashi, Masatoshi, Kakuishi, Yutaka
• Primary Examiner(s): Resan, Stevan A.
• Application Number:
  US09/259,290
• Time in Patent Office: 799 Days
• Field of Search: 428/98, 428/323, 428/336, 428/220, 428/694 BS, 428/694 BB, 428/694 SL, 428/216, 428/480, 428/900, 360/134
• US Class Current: 428/98
• CPC Class Codes: G11B 5/733 characterised by the addition of non-magnetic particles base layers having a non-magnetic layer under a soft magnetic layer G11B5/736; magnetic recording media substrates G11B5/739
• CPC Class Codes: G11B 5/7356 comprising non-magnetic particles in the back layer, e.g. particles of TiO2, ZnO or SiO2
• CPC Class Codes: G11B 5/7358 specially adapted for achieving a specific property, e.g. average roughness [Ra]
• CPC Class Codes: G11B 5/73929 comprising naphthalene ring compounds, e.g. polyethylene naphthalate substrates
• CPC Class Codes: Y10S 428/90 Magnetic feature
• CPC Class Codes: Y10T 428/24 Structurally defined web or sheet [e.g., overall dimension, etc.]
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]

Abstract

A magnetic recording tape favorably employable for recording computer data is composed of a support, and on one side of the support, a non-magnetic layer composed of a non-magnetic powder and a binder, and a magnetic recording layer composed of a ferromagnetic powder and a binder superposed in order, and on the other side, a back-coating layer containing carbon black, in which the magnetic recording tape has a lateral thermal expansion coefficient of not more than 0.0015%/° C., a lateral humidity expansion coefficient of not more than 0.0015%/% RH, a longitudinal offset proof stress of not less than 10 N, and a longitudinal breaking strength of not less than 30 N.

Claims

1. A magnetic recording tape comprising a support, and on one side of the support, a non-magnetic layer comprising a non-magnetic powder and a binder, and a magnetic recording layer comprising a ferromagnetic powder and a binder superposed in order, and on the other side, a back-coating layer containing carbon black, wherein said magnetic recording tape has a lateral thermal expansion coefficient of not more than 0.0015%/°

C., a lateral humidity expansion coefficient of not more than 0.0015%/%RH, a longitudinal offset proof stress of not less than 10 N, and a longitudinal breaking strength of not less than 30 N, and

wherein servo signals for controlling a magnetic recording or reproducing head are longitudinally recorded on said tape so as to position the head at a predetermined position along a width direction of the recording tape.

2. The magnetic recording tape of claim 1, wherein said magnetic recording tape has a width of 5 to 13 mm.

3. The magnetic recording tape of claim 1, wherein said magnetic recording tape has a total thickness of 5 to 10 μ

m.

4. The magnetic recording tape of claim 1, wherein the support has a lateral Young'"'"'s modulus of not less than 600 kg/mm².

5. The magnetic recording tape of claim 4, wherein the support has a lateral Young'"'"'s modulus in the range of 650 to 700 kg/mm².

6. The magnetic recording tape of claim 1, wherein the support has a longitudinal Young'"'"'s modulus of not less than 750 kg/mm².

7. The magnetic recording tape of claim 6, wherein the support has a longitudinal Young'"'"'s modulus in the range of 800 to 850 kg/mm².

8. The magnetic recording tape of claim 1, wherein the support is made of polyethylene naphthalate.

9. The magnetic recording tape of claim 1, which has a lateral Young'"'"'s modulus of not less than 650 kg/mm².

10. The magnetic recording tape of claim 9, which has a lateral Young'"'"'s modulus in the range of 730 to 800 kg/mm².

11. The magnetic recording tape of claim 10, which has a longitudinal Young'"'"'s modulus in the range of 1,000 to 1,100 kg/mm².

12. The magnetic recording tape of claim 1, which has a longitudinal Young'"'"'s modulus of not less than 950 kg/mm².

13. The magnetic recording tape of claim 1, which has a width of 5 to 13 mm.

14. The magnetic recording tape of claim 13, which has a width of 10 to 13 mm.

15. The magnetic recording tape of claim 1, which has a total thickness of 5 to 10 μ

m.

16. The magnetic recording tape of claim 15, which has a total thickness of 7.5 to 9.5 μ

m.

17. The magnetic recording tape of claim 1, wherein the carbon black comprises a combination of two kinds of carbon blacks having different mean particle sizes, one carbon black comprising relatively fine particles having a mean particle size of 10 to 30 mμ

, and the other carbon black comprising relatively crude particles having a mean particle size of 150 to 300 mμ

.

18. The magnetic recording tape of claim 1, wherin the back-coating layer further contains an inorganic material powder having Moh'"'"'s scale of hardness of 5 to 9.

19. The magnetic recording tape of claim 18, wherein the inorganic material powder has a mean particle size of 0.08 to 1 μ

m.

20. The magnetic recording tape of claim 18, wherein the inorganic material powder is α

-alumina.

21. The magnetic recording tape of claim 1, wherin the back-coating layer has a thickness of 0.2 to 0.8 μ

m.

22. In a magnetic recording and reproducing system comprising the steps of recording magnetic signals to a magnetic recording tape and detecting said magnetically recorded signals in said magnetic tape with a magnetoresistive reproducing head, the improvement characterized in that said magnetic recording tape comprises a support, and on one side of the support, a non-magnetic layer comprising a non-magnetic powder and a binder, and a magnetic recording layer comprising a ferromagnetic powder and a binder superposed in order, and on the other side, a back-coating layer containing carbon black, wherein said magnetic recording tape has a lateral thermal expansion coefficient of not more than 0.0015%/°

C., a lateral humidity expansion coefficient of not more than 0.0015%/% RH, a longitudinal offset proof stress of not less than 10 N, and a longitudinal breaking strength of not less than 30 N.

23. The magnetic recording and reproducing system of claim 22, wherein said system comprises a multi-tracks linear recording.