Patents by Inventor Nobuo Akagi

Nobuo Akagi 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: 4985345
    Abstract: A recording material employing at least one leuco dye having formula (I), which is colored when brought into contact with a color developer capable of inducing color formation in the leuco dye: ##STR1## wherein R.sup.1 and R.sup.2 each represent an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group, an unsubstituted or substituted aralkyl group, or an unsubstituted or substituted aryl group, which R.sup.1 and R.sup.2 may form a ring in combination or a morpholine ring through an oxygen atom; R.sup.3 represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms or an aralkyloxy group; R.sup.4 and R.sup.5 each represent an alkyl group having 1 to 4 carbon atoms; and R.sup.6 represents hydrogen, an alkyl group having 1 to 4 carbon atoms or a halogen.
    Type: Grant
    Filed: January 22, 1990
    Date of Patent: January 15, 1991
    Assignee: Ricoh Company, Ltd.
    Inventors: Kunio Hayakawa, Hiromi Furuya, Hisanori Shimada, Masahiro Nakata, Kaoru Kodera, Kouji Oohara, Nobuo Akagi