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# (12) United States Patent 

# Naoe et al. 

# (54) MAGNETIC RECORDING MEDIUM 

(75) Inventors: Koji Naoe; Kiyomi Ejiri; Naoto Abe, all of Kanagawa (JP) 

(73) Assignee: Fui Photo Film Co., Ltd., Kanagawa (JP) 

( *) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by O days. 

(21) Appl. No.: 09/169,189 

(22) Filed: Oct. 8, 1998 

## (30) Foreign Application Priority Data 

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(51) Int. Cl.7 ........................................................ GllB 5/66 

(52) U.S. Cl. .................................... 428/694.134; 427/128; 427/129; 427/130; 427/131; 428/694 B; 428/694 BS; 428/694 BN 

(58) Field of Search ..................................... 427/128, 129, 427/130, 131, 599, 548, 502; 428/694 B, 900, 694 BS, 694 BN, 694 BY 

## (56) References Cited 

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## U.S. PATENT DOCUMENTS 

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# (10) Patent No.: US 6,203,934 Bl 

# Mar.20,2001 (45) Date of Patent: 

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U.S. application No. 08/976,822, filed Nov. 24, 1997, Satoshi Matsubaguchi, abandoned; filed as CIP 09/324,754. The Advantages of the Thin Magnetic Layer on a Metal Particulate Tape, IEEE Transactions on Magnetics, vol. 29, No. 6, Nov. 1993. 

Development of Particulate Recording Media with Ultra thin Magnetic Layer, IEICE Trans Electron, vol. E78-C. No. 11, Nov. 1995. 

Enabling technologies for a 100MB 3.5 floppy (ZIP™) disk drive, 220/SPIE vol. 2604 (No Date Available). 

Primary Examiner-Bernard Pianalto 

(74) Attorney, Agent, or Firm----Stroock & Stroock & Lavan LLP 

## (57) ABSTRACT 

A magnetic recording medium is described, which com› prises a support having thereon a magnetic layer comprising a ferromagnetic metal powder and a binder resin, wherein the coercive force (He) of the magnetic layer is from 2,100 to 3,000 Oe, SFD (switching field distribution) of the magnetic layer is 0.30 or less, and an average thickness: d of the magnetic layer is in the range of: d~ recording wave› length A/4. 

US006203934Bl 

## FOREIGN PATENT DOCUMENTS 

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## OTHER PUBLICATIONS 

## 35 Claims, No Drawings 

