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US4409633A Expired / Lapsed US ⏱️ 0.0 years remaining

Mn-Zn Single crystalline ferrite head and a method of making the same

Assignee: Akai Electric Co Ltd
•
Filing: 1981-04-03
•
Granted: 1983-10-11
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Expires: 2001-04-03
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Abstract

Abstract A magnetic head for magnetic tape recording and reproducing apparatus utilizing Mn-Zn single crystalline ferrite at least for the tip core or front portion of a head core where an air gap is formed, wherein different phases are locally precipitated only at the region including the air gap at the central portion thereof where a running magnetic tape contacts during the recording and reproducing operation of the apparatus. The output of the head is considerably increased with the ferrite noise inherent in single crystalline ferrite heads kept at a low level, in comparison with the conventional single crystalline ferrite heads in which the precipitation of the different phases is not limited to the above-noted region of the head core. The head is made by a method comprising disposing a masking film or coating of metal or oxide over the whole surfaces of the head core except for the above-mentioned region and treating the core at a temperature of 1,000° C.-1,200° C. under an atmosphere with an oxygen density of less than 3%.

Inventors

  • 👤 Hisashi Watanabe
  • 👤 Yoshiteru Urino
  • 👤 Shinichi Aotsu

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 15:04
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/2658; G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/193; Y; Y10; Y10S; Y10S264/00; Y10S264/58

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 75 words
A magnetic head, for a magnetic tape recording and reproducing apparatus, comprising: at least one head core, at least a part of which is made of Mn-Zn single crystalline ferrites where an air gap is formed; wherein different phases are locally precipitated only at a region including the air gap at the central portion thereof where a running magnetic tape is contacted during the recording and reproducing operations of the tape recording and reproducing apparatus.
Claim 2
Dependent Claim 75 words
A magnetic head, for a magnetic tape recording and reproducing apparatus, comprising: at least one head core, at least a part of which is made of Mn-Zn single crystalline ferrites where an air gap is formed; wherein different phases are locally precipitated only at a region including the air gap at the central portion thereof where a running magnetic tape is contacted during the recording and reproducing operations of the tape recording and reproducing apparatus.
Claim 3
Dependent Claim 20 words
A magnetic head according to claim 1, wherein the Mn-Zn single crystalline ferrites are Sn substituted Mn-Zn single crystalline ferrites.
Claim 4
Dependent Claim 15 words
A magnetic head according to claim 1, wherein the different phases are SnO 2 phases.

References Cited (Backward Citations)

US3629519A Cited
US3663767A Cited
US3739445A Cited
US4135218A Cited
US4320427A Cited
NL7901988A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1986-10-10 1987-04-11 1987-10-11 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1990-10-10 1991-04-11 1991-10-11 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1994-10-10 1995-04-11 1995-10-11 $7700.00 Window Closed / Lapsed

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