Title:
MAGNETIC RECORD MEDIUM
Document Type and Number:
Japanese Patent JP3153184
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain a medium suitable for short wavelength recording and to suppress increase in noise after long-term storage by forming a magnetic coating film containing a metal magnetic powder on one surface of a base body and forming a back coating layer containing a carbon black of primary particles or aggregates having a larger particle size than the major axial diameter of the metal magnetic powder on the other surface.
SOLUTION: The major axial diameter of the metal magnetic powder used for the magnetic coating film is specified to ≤0.8 μm considering the center recording wavelength and is preferably 0.2 μm from the viewpoint of resolution. As for carbon black, carbon black having various particle sizes is easily available and can be properly selected considering the major axial diameter of the metal magnetic powder. If the particle size of the carbon black is rather small, aggregates of several primary particles are prepared. Thereby, the obtd. medium gives high output for short wavelength recording with about ≤0.8 μm center recording wavelength which is required for a small-size video tape of high picture quality, and increase in noise due to storage is prevented.
More Like This:
Inventors:
Masayoshi Kawarai
Kenichiro Yoshida
Akira Kato
Kenichiro Yoshida
Akira Kato
Application Number:
JP19753098A
Publication Date:
April 03, 2001
Filing Date:
July 13, 1998
Export Citation:
Assignee:
Hitachi Maxell, Ltd.
International Classes:
G11B5/73; G11B5/70; G11B5/735; (IPC1-7): G11B5/735
Domestic Patent References:
| JP6025023A | ||||
| JP628328A | ||||
| JP63184916A |
Attorney, Agent or Firm:
NegishiMoto Kunio