Patents by Inventor James L. Hohman

James L. Hohman 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: 6852156
    Abstract: A process is provided in which a pigment is oxidated with ozone in an aqueous environment in which the mixture of ozone, water and pigment is subjected to a dispersive mixing operation; and/or the pH of the mixture is maintained in a range of 6-8, whereby the pigment is self-dispersing and preferably has an acid value of less than 3 ?moles/M2. Pigments from this process and ink jet inks containing the self-dispersing pigments, are also provided.
    Type: Grant
    Filed: May 23, 2001
    Date of Patent: February 8, 2005
    Assignee: E.I. du Pont de Nemours and Company
    Inventors: An-Gong Yeh, Michael J. Eiseman, Robert Paul Held, James L. Hohman, Dhiren V. Patel, Yia-Ching Ray, Harry Joseph Spinelli, Sandra L. Witman
  • Publication number: 20040149169
    Abstract: A method of producing self dispersible organic pigment particles stabilized by the method. The method includes modifying organic pigment particles and then contacting the surface modified particles with an aqueous vapor entrained in a carrier gas to produce the stabilized organic pigment particles. Typically the pigment particles are modified by exposing their surfaces to ozone or a plasma-activated process gas. The surface stabilizing method prevents the violent exothermic reaction, which occurs when surface modified pigment particles are exposed to ambient air. The method is accomplished in a device, which includes a reactor, means for introducing in the reactor aqueous vapor entrained in a carrier gas and an agitator assembly for deagglomerating during surface modification the pigment particles placed in the reactor.
    Type: Application
    Filed: January 22, 2004
    Publication date: August 5, 2004
    Inventors: An-Gong Yeh, Sandra L. Witman, James L. Hohman
  • Patent number: 6709507
    Abstract: A method of producing self dispersible organic pigment particles stabilized by the method. The method includes modifying organic pigment particles and then contacting the surface modified particles with an aqueous vapor entrained in a carrier gas to produce the stabilized organic pigment particles. Typically the pigment particles are modified by exposing their surfaces to ozone or a plasma-activated process gas. The surface stabilizing method prevents the violent exothermic reaction, which occurs when surface modified pigment particles are exposed to ambient air. The method is accomplished in a device, which includes a reactor, means for introducing in the reactor aqueous vapor entrained in a carrier gas and an agitator assembly for deagglomerating during surface modification the pigment particles placed in the reactor.
    Type: Grant
    Filed: August 23, 2002
    Date of Patent: March 23, 2004
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: An-Gong Yeh, Sandra L. Witman, James L. Hohman
  • Publication number: 20030077446
    Abstract: A method of producing self dispersible organic pigment particles stabilized by the method. The method includes modifying organic pigment particles and then contacting the surface modified particles with an aqueous vapor entrained in a carrier gas to produce the stabilized organic pigment particles. Typically the pigment particles are modified by exposing their surfaces to ozone or a plasma-activated process gas. The surface stabilizing method prevents the violent exothermic reaction, which occurs when surface modified pigment particles are exposed to ambient air. The method is accomplished in a device, which includes a reactor, means for introducing in the reactor aqueous vapor entrained in a carrier gas and an agitator assembly for deagglomerating during surface modification the pigment particles placed in the reactor.
    Type: Application
    Filed: August 23, 2002
    Publication date: April 24, 2003
    Inventors: An-Gong Yeh, Sandra L. Witman, James L. Hohman
  • Publication number: 20020014184
    Abstract: A process is provided in which a pigment is oxidated with ozone in an aqueous environment in which the mixture of ozone, water and pigment is subjected to a dispersive mixing operation; and/or the pH of the mixture is maintained in a range of 6-8, whereby the pigment is self-dispersing and preferably has an acid value of less than 3 &mgr;moles/M2. Pigments from this process and ink jet inks containing the self-dispersing pigments, are also provided.
    Type: Application
    Filed: May 23, 2001
    Publication date: February 7, 2002
    Inventors: An-Gong Yeh, Michael J. Eiseman, Robert Paul Held, James L. Hohman, Dhiren V. Patel, Yia-Ching Ray, Harry Joseph Spinelli, Sandra L. Witman
  • Patent number: 5193024
    Abstract: Apparatus and methods for modulating light involving the formation of bubbles in a normally opaque dye solution contained within a cell. The bubbles are created in the dye solution by focusing a beam from a laser in regions of the dye solution thereby vaporizing a solvent in the solution. When the bubble is formed, the modulator becomes substantially transparent in the region of the bubble. If the focused laser beam is turned off, the bubble condenses and the modulator again becomes opaque in the region of the condensed bubble.
    Type: Grant
    Filed: October 31, 1990
    Date of Patent: March 9, 1993
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: John A. Lawton, Evan D. Laganis, James L. Hohman, Jr.
  • Patent number: 5042895
    Abstract: An electro-optic waveguide structure having a single mode channeled waveguide pattern of the Mach-Zehnder configuration is formed in a substrate of potassium titanyl phosphate.
    Type: Grant
    Filed: September 4, 1990
    Date of Patent: August 27, 1991
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Michael P. Chouinard, Edward P. Gargiulo, James L. Hohman, Jr., Daniel B. Laubacher, Jiunn-You Liou, Moshe Oren, O. Robert Averitt, Patrick H. Wyant, Victoria Guerra-Brady
  • Patent number: 4917451
    Abstract: An electro-optic waveguide structure having a single mode channeled waveguide pattern of the Mach-Zehnder configuration is formed in a substrate of potassium titanyl phosphate.
    Type: Grant
    Filed: January 19, 1988
    Date of Patent: April 17, 1990
    Assignee: E. I. DuPont de Nemours and Company
    Inventors: Michael P. Chouinard, Edward P. Gargiulo, James L. Hohman, Jr., Daniel B. Laubacher, Jiunn-Yau Liou, Moshe Oren