Patents by Inventor Kasturi Rangan Srinivasan

Kasturi Rangan Srinivasan 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).

  • Publication number: 20100159378
    Abstract: This invention provides a toner with improved charge and charge stability by suitable addition of extra particulate additives (EPA) such as aluminum cerium oxide and/or cerium zirconium oxide. The additives may be combined with toner in a conical mixer having selected temperature control. The invention also provides toner which may provide reduced print quality defects such as ghosting or residual image and fade-to-color.
    Type: Application
    Filed: December 19, 2008
    Publication date: June 24, 2010
    Inventors: Kasturi Rangan Srinivasan, Rick Owen Jones
  • Publication number: 20100040968
    Abstract: A toner composition and method of providing such composition which may be used in a printer or printer cartridge. The composition may include toner particles mixed with silica particles having a primary particle size in the range of 30 nm to 60 nm present in the range of 0.1 to 2.0% by weight of the toner composition and silica particles having a primary particle size in the range of 60 nm to 150 nm present in the range of 0.1 to 2% by weight of the toner composition.
    Type: Application
    Filed: August 12, 2008
    Publication date: February 18, 2010
    Inventors: Ligia Aura Bejat, Rick Owen Jones, Bryan Patrick Livengood, Kasturi Rangan Srinivasan, Devon Jean Vaccaro Strain
  • Publication number: 20100040969
    Abstract: A toner composition and a method of making a toner composition wherein toner particles having an average size in the range of 1-25 ?m may be mixed with silica particles and alumina particles surface treated with an inorganic/organic compound. The silica particles may have a primary particle size in the range of 2 nm to 20 nm and may be present in the range of 0.01% to 3.0% by weight of the toner composition. The alumina particles surface treated with an inorganic/organic compound may be present in the range of 0.01% to 1.0% by weight of the toner composition.
    Type: Application
    Filed: August 12, 2008
    Publication date: February 18, 2010
    Inventors: Ligia Aura Bejat, Joseph Edward Johnson, Rick Owen Jones, Bryan Patrick Livengood, Kasturi Rangan Srinivasan, Devon Jean Vaccaro Strain
  • Patent number: 7435523
    Abstract: Chemically prepared toner is manufactured by aggregation in which the binder resin is a latex copolymer having a methacrylic acid ester of long chain, saturated alkyl, which may be lauryl methacrylate. This binder resin has a small amount by weight of acrylic acid component and has other nonionic components, which may be styrene and butyl acrylate moieties. Aggregation is carried out in an aqueous medium, which may have organic solvent components. The aggregation is then heated, and because of the selection of the binder resin to have the long chain ester, the heating step has minimal effect on particle size.
    Type: Grant
    Filed: June 1, 2005
    Date of Patent: October 14, 2008
    Assignee: Lexmark International, Inc.
    Inventors: John Melvin Olson, Kasturi Rangan Srinivasan
  • Publication number: 20080227020
    Abstract: The present disclosure relates to chemically processed toner, wherein fuser release agent (wax) may be dispersed in a fluid containing a dispersant. Introduced to the wax dispersion are one or more polymerizable monomers which may be polymerized to form a latex of polymer particles. The polymer particles may then serve as a binder for the formation of toner for use in an electrophotographic printer. The polymerizable monomers may utilize acrylic esters that include relatively long chain hydrocarbon type substitution.
    Type: Application
    Filed: March 14, 2007
    Publication date: September 18, 2008
    Inventors: Rick Owen Jones, Lale Gokbudak Lovell, Walter Mychajlowskij, John Melvin Olson, Kasturi Rangan Srinivasan
  • Patent number: 7358015
    Abstract: Plasticizers in a charge transfer layer to reduce surface cracking and crazing having a hydrocarbon chain, attached to a hindered phenol containing triazole or triazine moiety. Plasticizers found useful for this application can be used in a concentration (by weight of the charge transfer layer) in the order of magnitude of 10% to about 25%. The plasticizer additive may also be used in combination with other known plasticizers such as those containing a 2-ethylhexyl group.
    Type: Grant
    Filed: June 3, 2005
    Date of Patent: April 15, 2008
    Assignee: Lexmark International, Inc.
    Inventors: Mark Thomas Bellino, Catherine Mailhé Randolph, Kasturi Rangan Srinivasan
  • Patent number: 7288350
    Abstract: A charge transfer layer system that encapsulates or surrounds high viscosity silicone oils (polysiloxanes) using silicone microspheres, fluoropolymers such as polytetrafluoroethylene or inorganic particles such as silica, or metal soaps (zinc stearate). The encapsulation of the silicone oil results in aggregation or agglomeration of the silicone microspheres, fluoropolymers, or inorganic particles. The silicone oils have viscosity greater than 10,000 centistokes (cs) and the particles are about 6 ?m or less.
    Type: Grant
    Filed: February 15, 2005
    Date of Patent: October 30, 2007
    Assignee: Lexmark International, Inc.
    Inventors: Donna Marie Erk, Kasturi Rangan Srinivasan
  • Patent number: 7195850
    Abstract: A photoconductor having a charge generation layer and a charge transport layer, the charge transport layer having hydrazone or aryl amine charge transport molecules and also having as room light protective additives acetosol yellow 5GLS and tetraphenylcyclopentadienone or 9-fluorenone. Preferably the amount of the acetosol yellow is 2 to 4 percent by weight of the weight of the charge transfer layer and the ratio of weight between the acetosol yellow and the dienone or fluorenone is in the range of 1:1 to 1:3.
    Type: Grant
    Filed: March 17, 2004
    Date of Patent: March 27, 2007
    Assignee: Lexmark International, Inc.
    Inventor: Kasturi Rangan Srinivasan
  • Patent number: 6558751
    Abstract: A process for preparing fuser belts in electrophotographic devices is disclosed. In this process the belt is coated, preferably using a vertical dip coating technique, with an aqueous solution containing a fluorocarbon polymer, such as Teflon, and a water-soluble polymer additive. Preferred additives include pectin, polyacrylic acid, and pectin/polyacrylic acid mixtures. This method provides efficient and effective vertical dip coating of the topcoat onto the fuser belt, particularly in terms of the uniformity of the coating, the stability of the coating dispersion, and the minimization of cracking when the coating is dried and sintered at high temperatures.
    Type: Grant
    Filed: August 15, 2001
    Date of Patent: May 6, 2003
    Assignee: Lexmark International, Inc.
    Inventors: Mark Thomas Bellino, Scott Moreland Broce, Jennifer Kaye Neely, Dat Quoc Nguyen, Kasturi Rangan Srinivasan
  • Publication number: 20030068445
    Abstract: A process for preparing fuser belts in electrophotographic devices is disclosed. In this process the belt is coated, preferably using a vertical dip coating technique, with an aqueous solution containing a fluorocarbon polymer, such as Teflon, and a water-soluble polymer additive. Preferred additives include pectin, polyacrylic acid, and pectin/polyacrylic acid mixtures. This method provides efficient and effective vertical dip coating of the topcoat onto the fuser belt, particularly in terms of the uniformity of the coating, the stability of the coating dispersion, and the minimization of cracking when the coating is dried and sintered at high temperatures.
    Type: Application
    Filed: August 15, 2001
    Publication date: April 10, 2003
    Inventors: Mark Thomas Bellino, Scott Moreland Broce, Jennifer Kaye Neely, Dat Quoc Nguyen, Kasturi Rangan Srinivasan
  • Patent number: 6511709
    Abstract: A process for dip coating, particularly vertical dip coating, the topcoat layer onto fuser belts used in electrophotographic processes is disclosed. In this process, a C1-C4 alkanol, such as isopropyl alcohol is added to the solvent system for the fluorocarbon topcoat layer. The use of alcohols in this way provides an efficient and effective method and a topcoat layer which is smooth, uniform and has a good finish.
    Type: Grant
    Filed: August 15, 2001
    Date of Patent: January 28, 2003
    Assignee: Lexmark, International, Inc.
    Inventors: Johnathan Lee Barnes, Scott Moreland Broce, James Craig Minor, Jennifer Kaye Neely, Dat Quoc Nguyen, Kasturi Rangan Srinivasan, Mark Stephen Weisman, Jr.
  • Patent number: 6461781
    Abstract: Polycarbonate diols and polyethercarbonate diols having only aliphatic hydrocarbon moieties are useful as co-binders in the charge transport layers of electrophotographic photoreceptors of xerographic printers and copiers. Preferably, the co-binders have number molecule or weights of from about 200 to about 2000.
    Type: Grant
    Filed: July 2, 2001
    Date of Patent: October 8, 2002
    Assignee: Lexmark International, Inc.
    Inventor: Kasturi Rangan Srinivasan
  • Patent number: 6410197
    Abstract: Methods of forming a conductive aluminum substrate comprise anodizing a surface of an aluminum substrate to form a porous alumina surface layer, contacting the alumina surface layer with a liquid dispersion or solution of a polymer or at least one polymer-forming component, under conditions sufficient for the polymer to seal pores of the alumina surface layer, and removing excess polymer from the alumina surface layer. The resulting sealed conductive aluminum substrate is useful in photoconductors, for example of the dual layer type.
    Type: Grant
    Filed: September 18, 1998
    Date of Patent: June 25, 2002
    Assignee: Lexmark International, Inc.
    Inventors: Mark Thomas Bellino, Jennifer Kaye Neely, Catherine Mailhé Randolph, Kasturi Rangan Srinivasan
  • Patent number: 6300025
    Abstract: A photoconductor having a charge generation layer of pigment and a binder resin of a thorough mixture of polyvinylbutyral, a polysiloxane, and, preferably, a phenolic resin. An optimum formulation was Type IV oxotitanium phthalocyanine in a binder of, by weight 50 parts polyvinylbutyral, 45 parts poly(methyl-phenyl)siloxane, and 5 parts polyhydroxystyrene. This photoconductor provides excellent electrical properties and consistent, economical coating results.
    Type: Grant
    Filed: June 1, 2000
    Date of Patent: October 9, 2001
    Assignee: Lexmark International, Inc.
    Inventors: Gregory Walter Haggquist, Scott Thomas Mosier, Kasturi Rangan Srinivasan
  • Patent number: 6042980
    Abstract: Charge generation layers for photoconductors comprise a binder and a charge generation compound, wherein the binder comprises a blend of polyvinylbutyral polymer and at least one resin which improves at least one electrical characteristic of a photoconductor in which the charge generation layer is included. Photoconductors comprise the charge generation layer in combination with a substrate and a charge transport layer.
    Type: Grant
    Filed: July 21, 1998
    Date of Patent: March 28, 2000
    Assignee: Lexmark Internatonal, Inc.
    Inventors: Laura Lee Kierstein, Kasturi Rangan Srinivasan
  • Patent number: 6040098
    Abstract: Charge generation layers comprising a binder and a charge generation compound, wherein the binder comprises a blend of methyl bisphenol A and an additional resin comprising an epoxy resin, a poly(phenylglycidyl ether)-co-dicyclopentadiene resin, a phenoxy resin or a polyhydroxystyrene resin. Dual layer photoconductors comprise the charge generation layer in combination with a substrate and a charge transport layer.
    Type: Grant
    Filed: November 20, 1998
    Date of Patent: March 21, 2000
    Assignee: Lexmark International, Inc.
    Inventors: David Glenn Black, Garry Dale Hinch, Dat Quoc Nguyen, Kasturi Rangan Srinivasan
  • Patent number: 6033816
    Abstract: A photoconductive drum of an aluminum substrate and a blend of polyvinylbutyral and one or a blend of phenoxy resin, epoxy novolac resin, and epoxy capped polymers which are derivatives of bisphenol and epichlorohydrin. The blend enhances the electrical properties.
    Type: Grant
    Filed: November 14, 1997
    Date of Patent: March 7, 2000
    Assignee: Lexmark International, Inc.
    Inventors: Weimei Luo, Kasturi Rangan Srinivasan, Julie Corrin House
  • Patent number: 6001523
    Abstract: The invention described in the specification provides an improved coating for an electrophotographic photoconductor printing system. In particular, a blend of polycarbonate-A and polycarbonate-Z binders according to the formula: ##STR1## wherein R.sup.1 is selected from the group consisting of CH.sub.2 an alkylidene group, a cycloalkyl group and a substituted cycloalkyl group, R.sup.2 and R.sup.3 are selected from the group consisting of hydrogen, halogen and an a CH.sub.3 group provides increased durability and wear properties to a charge transport layer coated onto a charge generation layer of a photoreceptor drum. The polycarbonate blend may be used with amine and hydrazone charge transport materials and the charge transport layer may include additional additives which further improve the wear properties of the photoconductor coatings in a laser printer.
    Type: Grant
    Filed: October 29, 1998
    Date of Patent: December 14, 1999
    Assignee: Lexmark International, Inc.
    Inventors: Paul Dwight Kemmesat, Jennifer Kaye Neely, Catherine Mailhe Randolph, Kasturi Rangan Srinivasan