Patents by Inventor Noboru Nakajima

Noboru Nakajima has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5026598
    Abstract: There is disclosed a magnetic recording medium comprising a support and provided thereon a plurality of layers. The layers comprise an outermost magnetic layer and a lower magnetic layer, wherein the outermost magnetic layer contains carbon black having an average primary particle size ranging from 40 m.mu. to 300 m.mu., and the lower magnetic layer contains carbon black having an average primary particle size ranging from 5 m.mu. to 30 m.mu..
    Type: Grant
    Filed: December 11, 1989
    Date of Patent: June 25, 1991
    Assignee: Konica Corporation
    Inventors: Noboru Koyama, Yasushi Nakano, Setsuko Kawahara, Noboru Nakajima
  • Patent number: 4992330
    Abstract: A magnetic recording medium is disclosed, which has excellent electro-magnetic conversion characteristics and is improved in drop-out. The magnetic recording medium comprises a non-magnetic support and a plurality of magnetic layers provided on the support, and the magnetic layer being provided farthest from said support among these magnetic layers comprises a magnetic powder and a carbon black in an amount of not more than 1 part per 100 parts by weight of said magnetic powder; and another magnetic layer comprising a magnetic powder has a thickness of not more than 2.5 .mu.m, and 900 nm light-transmittance of said magnetic medium is not more than 0.1%.
    Type: Grant
    Filed: December 11, 1989
    Date of Patent: February 12, 1991
    Assignee: Konica Corporation
    Inventors: Setsuko Kawahara, Noboru Koyama, Yasushi Nakano, Noboru Nakajima