Patents by Inventor Hirotsugu Nishikawa

Hirotsugu Nishikawa 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: 5153088
    Abstract: This invention provides an electrophotosensitive material comprising a conductive substrate and a photosensitive layer formed thereon, the photosensitive layer includes a perylene compound (I) and an X-type metal-free phtalocyanine as a charge-generating ingredient and a diamine derivative (II) as a charge-transferring ingredient in the binding resin. This electrophotosensitive material is especially superior in sensitivity and reproductivity. Formulas (I) and (II) are defined as follows: ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9 l, m, n, o and p have the same meanings as defined in the text of the specification.
    Type: Grant
    Filed: February 28, 1990
    Date of Patent: October 6, 1992
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Nariaki Muto, Tatsuo Maeda, Hirotsugu Nishikawa, Mikio Kakui, Keisuke Sumida, Toru Nakazawa
  • Patent number: 4968579
    Abstract: Disclosed is an organic laminated photosensitive material of the positive charging type comprising an electroconductive substrate, a charge-transporting layer formed on the substrate and a charge-generating and transporting layer formed on the charge-transporting layer. The charge-transporting layer is composed of a binder resin containing a hole-transporting substance, and the charge-generating and transporting layer is composed of a binder resin containing a hole-transporting substance different from the hole-transporting substance in the charge-transporting layer and a charge-generating substance. The oxidation potential of the hole-transporting substance in the charge-generating and transporting layer is higher than that of the hole-transporting substance in the charge-transporting layer, but the difference of the oxidation potential between the hole-transporting substances of the two layers is smaller than 0.3 eV.
    Type: Grant
    Filed: April 4, 1990
    Date of Patent: November 6, 1990
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Keizo Kimoto, Masashi Tanaka, Hirotsugu Nishikawa
  • Patent number: 4882253
    Abstract: Disclosed is an organic laminated photosensitive material of the positive charging type comprising an electroconductive substrate, a charge-transporting layer formed on the substrate and a charge-generating and transporting layer formed on the charge-transporting layer. The charge-transporting layer is composed of a binder resin containing a hole-transporting substance, and the charge-generating and transporting layer is composed of a binder resin containing a charge-generating substance and a hole-transporting substance. In this laminated photosensitive material, an excellent sensitiveity is maintained even if the topmost charge-generating layer has a large thickness, and therefore, a high surface saturation charge voltage and an excellent printing resistance can be maintained in addition to an increased sensitivity.
    Type: Grant
    Filed: July 28, 1988
    Date of Patent: November 21, 1989
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Yoshiaki Kato, Masashi Tanaka, Mitsuji Tsujita, Keizo Kimoto, Hirotsugu Nishikawa, Mika Kawaguchi