Patents by Inventor Palitha Wickramanayake

Palitha Wickramanayake 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: 8287633
    Abstract: In one aspect of the present system and method, a pigment-based ink includes an acidic pigment-based ink formulation, and a pigment load less than 5 weight percent, where an amphoteric dispersant maintains the pigment distributed in the acidic pigment-based ink formulation, wherein the amphoteric dispersant has an isoelectric point, and wherein the amphoteric dispersant has a higher isoelectric point than the pH of the acidic pigment-based ink formulation.
    Type: Grant
    Filed: September 29, 2005
    Date of Patent: October 16, 2012
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: Palitha Wickramanayake
  • Patent number: 8052786
    Abstract: Ink-jet ink sets, pigment-based ink formulations, methods of printing, and methods of enhancing print quality, are disclosed. One exemplary ink-jet ink set, among others, includes a pigment-based ink formulation at a first pH, including: a pigment-based ink, and an amphoteric dispersant having an isoelectric point; and a second ink formulation at a second pH, wherein the first pH and the second pH are each selected from an acidic pH and a basic pH, wherein the first pH and the second pH are not the same, and wherein the amphoteric dispersant has a higher isoelectric point than the first pH when the dispersant is acidic, and a lower isoelectric point than the first pH when the dispersant is basic.
    Type: Grant
    Filed: January 7, 2010
    Date of Patent: November 8, 2011
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: Palitha Wickramanayake
  • Patent number: 7919176
    Abstract: The present invention is drawn to a coated substrate for ink-jet ink printing comprising a substrate, having coated thereon, a porous coating, wherein the porous coating comprises silica covalently attached to a chelating agent, an ultraviolet blocker, and/or a hindered amine light stabilizer. In one embodiment, the chelating agent, ultraviolet blocker, and/or hindered amine light stabilizer can be substantially homogenously distributed on the silica.
    Type: Grant
    Filed: April 10, 2002
    Date of Patent: April 5, 2011
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: Palitha Wickramanayake
  • Patent number: 7740920
    Abstract: Silica-based, chemically-bonded porous coatings, synthesized via the reaction of organo silanes with silica, are used as coatings for inkjet image printing. Silica is used as the base material in all cases, due to its favorable chemical properties of the surface, and the favorable pore structure. The silane-silica reaction product substantially retains the original pore structure of the pre-reacted silica. The disclosed embodiments solve the problems in the prior art in that any catalytic activity of the silica surface towards image fade is eliminated by the chemical modification of silica. This improves the image fade and humid fastness properties of the coating.
    Type: Grant
    Filed: October 10, 2008
    Date of Patent: June 22, 2010
    Assignee: Hewlett-Packard Development, L.P.
    Inventors: Palitha Wickramanayake, James P. Shields
  • Publication number: 20100112221
    Abstract: Ink-jet ink sets, pigment-based ink formulations, methods of printing, and methods of enhancing print quality, are disclosed. One exemplary ink-jet ink set, among others, includes a pigment-based ink formulation at a first pH, including: a pigment-based ink, and an amphoteric dispersant having an isoelectric point; and a second ink formulation at a second pH, wherein the first pH and the second pH are each selected from an acidic pH and a basic pH, wherein the first pH and the second pH are not the same, and wherein the amphoteric dispersant has a higher isoelectric point than the first pH when the dispersant is acidic, and a lower isoelectric point than the first pH when the dispersant is basic.
    Type: Application
    Filed: January 7, 2010
    Publication date: May 6, 2010
    Inventor: Palitha WICKRAMANAYAKE
  • Patent number: 7699461
    Abstract: Systems and methods for producing permanent ink-jet images are provided. In one embodiment, a system includes a media substrate coated with a porous media coating, wherein the porous media coating having inorganic porous particulates, and wherein at least a portion of the inorganic porous particulates have a first reactive group covalently attached thereto. The system further includes an ink-jet ink containing a dye, wherein the dye includes a second reactive group, and wherein the first reactive group and the second reactive group are configured to react with one another upon contact to form a covalent bond.
    Type: Grant
    Filed: April 5, 2007
    Date of Patent: April 20, 2010
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Vladek P Kasperchik, Palitha Wickramanayake, James P Shields, Gary Allan Ungefug
  • Patent number: 7677720
    Abstract: Ceramic pigment-based, chemically-modified porous coatings can be used for enhancing image permanence of ink-jet image printing. Specifically, a porous coated media sheet, comprising a media substrate, having a porous coating coated thereon comprising a modified ceramic pigment including a fixer group and a stabilizer group, each covalently attached to the ceramic pigment is disclosed. Additionally, a method and system for preparing permanent ink-jet images is also provided.
    Type: Grant
    Filed: August 2, 2005
    Date of Patent: March 16, 2010
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Kent D. Vincent, Sivapackia Ganapathiappan, Sean Xiao-An Zhang, Palitha Wickramanayake
  • Patent number: 7666256
    Abstract: Ink-jet ink sets, pigment-based ink formulations, methods of printing, and methods of enhancing print quality, are disclosed. One exemplary ink-jet ink set, among others, includes a pigment-based ink formulation at a first pH, including: a pigment, and an amphoteric dispersant having an isoelectric point; and a second ink formulation at a second pH, wherein the first pH and the second pH are each selected from an acidic pH and a basic pH, wherein the first pH and the second pH are not the same, and wherein the amphoteric dispersant has a higher isoelectric point than the first pH when the dispersant is acidic, and a lower isoelectric point than the first pH when the dispersant is basic.
    Type: Grant
    Filed: October 28, 2004
    Date of Patent: February 23, 2010
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: Palitha Wickramanayake
  • Patent number: 7638166
    Abstract: Methods of preparing media sheets for inkjet printing applications are provided. In one embodiment, the media sheets can be prepared by dispersing or dissolving inorganic porous particulates and an active ligand-containing organosilane reagent in water; reacting the inorganic porous particulates and the active ligand-containing organosilane reagent to form media coating composition; and applying the media coating composition to a media substrate. In another embodiment, the media sheets can be prepared by coating a media substrate with inorganic porous particulates; dispersing or dissolving an active ligand-containing organosilane reagent in water to form a liquid coating composition; and applying the liquid coating composition to the inorganic porous particulates that has previously been coated on the substrate.
    Type: Grant
    Filed: February 14, 2005
    Date of Patent: December 29, 2009
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: Palitha Wickramanayake
  • Publication number: 20090087594
    Abstract: An additive used in a print medium to reduce bronzing. The additive increases a pH of the print medium. The additive is an organic base or an inorganic base. The additive reduces bronzing of an image printed with a dye-based inkjet ink.
    Type: Application
    Filed: October 9, 2008
    Publication date: April 2, 2009
    Inventors: Palitha WICKRAMANAYAKE, Matthew THORNBERRY, Linda C. UHLIR-TSANG
  • Publication number: 20090031922
    Abstract: An ink composition includes an anionic acrylate copolymer binder, an oxidized self-dispersible pigment, and an aqueous vehicle.
    Type: Application
    Filed: July 30, 2007
    Publication date: February 5, 2009
    Inventors: Sukanya Rengaswamy, Robert J. Blair, Sundar Vasudevan, Palitha Wickramanayake
  • Publication number: 20090035490
    Abstract: Silica-based, chemically-bonded porous coatings, synthesized via the reaction of organo silanes with silica, are used as coatings for inkjet image printing. Silica is used as the base material in all cases, due to its favorable chemical properties of the surface, and the favorable pore structure. The silane-silica reaction product substantially retains the original pore structure of the pre-reacted silica. The disclosed embodiments solve the problems in the prior art in that any catalytic activity of the silica surface towards image fade is eliminated by the chemical modification of silica. This improves the image fade and humid fastness properties of the coating.
    Type: Application
    Filed: October 10, 2008
    Publication date: February 5, 2009
    Inventors: Palitha Wickramanayake, James P. Shields
  • Patent number: 7449217
    Abstract: Silica-based, chemically-bonded porous coatings, synthesized via the reaction of organo silanes with silica, are used as coatings for inkjet image printing. Silica is used as the base material in all cases, due to its favorable chemical properties of the surface, and the favorable pore structure. The silane-silica reaction product substantially retains the original pore structure of the pre-reacted silica. The disclosed embodiments solve the problems in the prior art in that any catalytic activity of the silica surface towards image fade is eliminated by the chemical modification of silica. This improves the image fade and humid fastness properties of the coating.
    Type: Grant
    Filed: May 25, 2004
    Date of Patent: November 11, 2008
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Palitha Wickramanayake, James P. Shields
  • Publication number: 20070188579
    Abstract: Systems and methods for producing permanent ink-jet images are provided. In one embodiment, a system comprises a media substrate coated with a porous media coating, wherein the porous media coating comprises inorganic porous particulates, and wherein at least a portion of the inorganic porous particulates have a first reactive group covalently attached thereto. The system further includes an ink-jet ink containing a dye, wherein the dye comprises a second reactive group, and wherein the first reactive group and the second reactive group are configured to react with one another upon contact to form a covalent bond.
    Type: Application
    Filed: April 5, 2007
    Publication date: August 16, 2007
    Inventors: Vladek Kasperchik, Palitha Wickramanayake, James Shields, Gary Ungefug
  • Patent number: 7226647
    Abstract: Systems and methods for producing permanent ink-jet images are provided. In one embodiment, a system comprises a media substrate coated with a porous media coating, wherein the porous media coating comprises inorganic porous particulates, and wherein at least a portion of the inorganic porous particulates have a first reactive group covalently attached thereto. The system further includes an ink-jet ink containing a dye, wherein the dye comprises a second reactive group, and wherein the first reactive group and the second reactive group are configured to react with one another upon contact to form a covalent bond.
    Type: Grant
    Filed: October 16, 2003
    Date of Patent: June 5, 2007
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Vladek P Kasperchik, Palitha Wickramanayake, James P Shields, Gary Allan Ungefug
  • Publication number: 20060092252
    Abstract: In one aspect of the present system and method, a pigment-based ink includes an acidic pigment-based ink formulation, and a pigment load less than 5 weight percent, where an amphoteric dispersant maintains the pigment distributed in the acidic pigment-based ink formulation, wherein the amphoteric dispersant has an isoelectric point, and wherein the amphoteric dispersant has a higher isoelectric point than the pH of the acidic pigment-based ink formulation.
    Type: Application
    Filed: September 29, 2005
    Publication date: May 4, 2006
    Inventor: Palitha Wickramanayake
  • Publication number: 20060092250
    Abstract: Ink-jet ink sets, pigment-based ink formulations, methods of printing, and methods of enhancing print quality, are disclosed. One exemplary ink-jet ink set, among others, includes a pigment-based ink formulation at a first pH, including: a pigment, and an amphoteric dispersant having an isoelectric point; and a second ink formulation at a second pH, wherein the first pH and the second pH are each selected from an acidic pH and a basic pH, wherein the first pH and the second pH are not the same, and wherein the amphoteric dispersant has a higher isoelectric point than the first pH when the dispersant is acidic, and a lower isoelectric point than the first pH when the dispersant is basic.
    Type: Application
    Filed: October 28, 2004
    Publication date: May 4, 2006
    Inventor: Palitha Wickramanayake
  • Publication number: 20050270350
    Abstract: Ceramic pigment-based, chemically-modified porous coatings can be used for enhancing image permanence of ink-jet image printing. Specifically, a porous coated media sheet, comprising a media substrate, having a porous coating coated thereon comprising a modified ceramic pigment including a fixer group and a stabilizer group, each covalently attached to the ceramic pigment is disclosed. Additionally, a method and system for preparing permanent ink-jet images is also provided.
    Type: Application
    Filed: August 2, 2005
    Publication date: December 8, 2005
    Inventors: Kent D. Vincent, Sivapackia Ganapathiappan, Sean Zhang, Palitha Wickramanayake
  • Publication number: 20050227096
    Abstract: A composition of matter includes an emulsion with a discontinuous phase of particle sol.
    Type: Application
    Filed: April 6, 2004
    Publication date: October 13, 2005
    Inventors: Phil Harding, Palitha Wickramanayake, Alexey Kabalnov, Niranjan Thirukkovalur
  • Patent number: 6951672
    Abstract: Ceramic pigment-based, chemically-modified porous coatings can be used for enhancing image permanence of ink-jet image printing. Specifically, a porous coated media sheet, comprising a media substrate, having a porous coating coated thereon comprising a modified ceramic pigment including a fixer group and a stabilizer group, each covalently attached to the ceramic pigment is disclosed. Additionally, a method and system for preparing permanent ink-jet images is also provided.
    Type: Grant
    Filed: July 30, 2003
    Date of Patent: October 4, 2005
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Kent D. Vincent, Sivapackia Ganapathiappan, Sean Xiao-An Zhang, Palitha Wickramanayake