Patents by Inventor Robert L. Vollmer

Robert L. Vollmer 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: 5545499
    Abstract: A photoconductor for use in electrophotographic reproduction devices is disclosed. This photoconductor exhibits improved oil resistance when used with liquid toners and excellent cycling stability. The photoconductors of the present invention utilize a phthalocyanine dye, particularly an X-form metal-free phthalocyanine, dispersed in a medium molecular weight polyvinyl chloride binder in the charge generating layer, and a charge transport molecule, particularly a hydrazone such as DEH, in a polyestercarbonate binder in the charge transport layer.
    Type: Grant
    Filed: July 7, 1995
    Date of Patent: August 13, 1996
    Assignee: Lexmark International, Inc.
    Inventors: Vernon M. Balthis, Ronald A. Merten, Robert J. Rumery, Robert L. Vollmer
  • Patent number: 5198022
    Abstract: A alkali-soluble dye for a waterfast ink having structural formula as follows: ##STR1## and an ink containing the dye dissolved in water. Printing from the ink is insoluble below pH 6.0; is an intense black at low concentration; and remains black on acid papers. The aqueous inks are stable and exhibit good printhead nozzle maintenance.
    Type: Grant
    Filed: January 17, 1992
    Date of Patent: March 30, 1993
    Assignee: Lexmark International, Inc.
    Inventors: Rodney O. Aulick, Bradley L. Beach, Donald L. Elbert, Terence E. Franey, James F. Feeman, John M. Olson, Allen C. Sanders, Robert L. Vollmer
  • Patent number: 5130215
    Abstract: A layered electrophotographic photoconductor is disclosed having a ground plane layer, a charge generating layer carried by the ground plane layer, and a charge transport layer carried by the charge generating layer. The polymeric binder material of the charge transport layer and the charge generation layer comprises an ordered copolyestercarbonate whose ester content is in the range of about 35 wt. % to about 70 wt. %, of which about 60 wt. % to about 70 wt. % is preferred, and of which about 70 wt. % is the most preferred. The charge generating molecule is a squarylium, and more specifically 2,4-bis-(4-dimethylamino-2-hydroxyphenyl) cyclobutene diylium-1,3-diolate (OHSQ), or an operative phthalocyanine compound, and preferably oxytitanium phthalocyanine. The charge transporting molecule is a hydrazone, and more specifically 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone (DEH), or 4-diphenylaminobenzaldehyde-1,1-diphenylhydrazone (TPH).
    Type: Grant
    Filed: September 28, 1990
    Date of Patent: July 14, 1992
    Assignee: Lexmark International, Inc.
    Inventors: James M. Adley, Vernon M. Balthis, Dean S. Ehn, Ralph F. Fox, Jacob Pacansky, Robert L. Vollmer, Robert J. Waltman
  • Patent number: 4677045
    Abstract: A squarylium dye molecule is synthesized from a phenolic precursor. The resulting hydroxy pyrrolidino squarylium (OHPYRRSQ) dye does not have to be purified in order to provide the dye with a negative response in the Ames test for mutagenicity. A xerographic photoconductor using the molecule shows superior electrophotographic performance.
    Type: Grant
    Filed: May 5, 1986
    Date of Patent: June 30, 1987
    Assignee: International Business Machines Corporation
    Inventors: Robert B. Champ, Robert L. Vollmer