Patents by Inventor Raj D. Patel

Raj D. Patel 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: 5977210
    Abstract: A process for the preparation of ink compositions comprising the emulsion polymerization of monomer, water, surfactant, and initiator with stirring and heating to provide a latex; mixing therewith a pigment dispersion of pigment particles, water, and cationic surfactant; blending the mixture; thereafter stirring the mixture; and subsequently adding additional anionic surfactant to stabilize the aggregate particles.
    Type: Grant
    Filed: January 30, 1995
    Date of Patent: November 2, 1999
    Assignee: Xerox Corporation
    Inventors: Raj D. Patel, Marcel P. Breton, Michael A. Hopper, Grazyna E. Kmiecik-Lawrynowicz, Beng S. Ong
  • Patent number: 5958998
    Abstract: An ink composition comprised of from about 20 to about 80 weight percent of water, from about 1 to about 25 weight percent of pigmented polymer, oil soluble colorant, and optionally from about 2 to about 50 weight percent of a glycol, and wherein the oil soluble colorant is present in an amount of from about 0.01 to about 30 weight percent of the pigmented polymer.
    Type: Grant
    Filed: February 5, 1998
    Date of Patent: September 28, 1999
    Assignee: Xerox Corporation
    Inventors: Daniel A. Foucher, Raj D. Patel, Patricia A. Burns, Marcel P. Breton, Guerino G. Sacripante
  • Patent number: 5945245
    Abstract: A surfactant free process for the preparation of toner comprising heating a mixture of an emulsion latex, a colorant, and an organic complexing agent.
    Type: Grant
    Filed: January 13, 1998
    Date of Patent: August 31, 1999
    Assignee: Xerox Corporation
    Inventors: Walter Mychajlowskij, Guerino G. Sacripante, Daniel A. Foucher, Raj D. Patel, Stephan V. Drappel
  • Patent number: 5936008
    Abstract: An ink for ink jet printing includes a liquid vehicle comprising water and toner particles with a colorant dispersed in or associated with the toner particles. The ink composition combines the print quality advantages of xerographic printing with the economic advantages of ink jet printing, thereby providing waterfast, archival quality prints.
    Type: Grant
    Filed: November 21, 1995
    Date of Patent: August 10, 1999
    Assignee: Xerox Corporation
    Inventors: Robert N. Jones, Edward J. Radigan, Jr., Susan Robinette, Raj D. Patel, Michael A. Hopper, Grazyna E. Kmiecik-Lawrynowicz, Garland J. Nichols, Beng S. Ong
  • Patent number: 5925488
    Abstract: A process for the preparation of toner which comprises(i) preparing a pigment dispersion comprised of a pigment dispersed in an ionic surfactant;(ii) shearing said pigment dispersion with a latex or emulsion blend comprised of resin particles and a counterionic surfactant;(iii) heating the above sheared blend below the glass transition temperature (Tg) of said resin particles to form electrostatically bound toner size aggregates;(iv) adding a stabilizer of in situ tricalcium phosphate solid particulants generated from a solution of calcium chloride and trisodium phosphate;(v) heating the mixture of (iii) and (iv) above about the Tg of the resin particles to obtain toner size particles comprised of resin and pigment;(vi) washing with an acid to dissolve the trisodium phosphate; and(vii) optionally washing with water, and optionally drying the toner obtained.
    Type: Grant
    Filed: November 18, 1997
    Date of Patent: July 20, 1999
    Assignee: Xerox Corporation
    Inventors: Raj D. Patel, Grazyna E. Kmieckik-Lawrynowicz, Anthony J. Paine, T. Hwee Ng
  • Patent number: 5919595
    Abstract: A process for the preparation of toner comprising mixing an emulsion latex, a colorant dispersion, and monocationic salt, and which mixture possesses an ionic strength of from about 0.001 molar (M) to about 5 molar, and optionally cooling.
    Type: Grant
    Filed: January 13, 1998
    Date of Patent: July 6, 1999
    Assignee: Xerox Corporation
    Inventors: Walter Mychajlowskij, Daniel A. Foucher, Guerino G. Sacripante, Raj D. Patel, Beng S. Ong
  • Patent number: 5916725
    Abstract: A process for the preparation of toner comprising mixing an amine, an emulsion latex containing sulfonated polyester resin, and a colorant dispersion, heating the resulting mixture, and optionally cooling.
    Type: Grant
    Filed: January 13, 1998
    Date of Patent: June 29, 1999
    Assignee: Xerox Corporation
    Inventors: Raj D. Patel, Walter Mychajlowskij, Daniel A. Foucher, Guerino G. Sacripante, Beng S. Ong
  • Patent number: 5910387
    Abstract: A toner composition comprised of colorant, and an addition polymer resin of styrene, butadiene, acrylonitrile and acrylic acid.
    Type: Grant
    Filed: January 13, 1998
    Date of Patent: June 8, 1999
    Assignee: Xerox Corporation
    Inventors: Walter Mychajlowskij, Beng S. Ong, Emily L. Moore, Raj D. Patel
  • Patent number: 5902710
    Abstract: A process for the preparation of toner comprising(i) preparing, or providing an aqueous colorant dispersion, which dispersion is comprised of a colorant and an ionic surfactant in water;(ii) blending said colorant dispersion with a latex emulsion comprised of resin particles, a nonionic surfactant, and an ionic surfactant of opposite charge polarity to that of the ionic surfactant in said colorant dispersion;(iii) heating the resulting mixture below about the glass transition temperature (Tg) of the latex resin to form toner sized aggregates;(iv) heating the resulting aggregate suspension of (iii) above about the Tg of the latex resin; and(v) retaining the temperature in the range of from about 30.degree. C. to about 95.degree. C.
    Type: Grant
    Filed: August 12, 1998
    Date of Patent: May 11, 1999
    Assignee: Xerox Corporation
    Inventors: Beng S. Ong, Raj D. Patel
  • Patent number: 5869216
    Abstract: A process for the preparation of toner comprising blending an aqueous colorant dispersion and a latex emulsion containing resin; heating the resulting mixture at a temperature below about the glass transition temperature (Tg) of the latex resin to form toner sized aggregates; heating said resulting aggregates at a temperature above about the Tg of the latex resin to effect fusion or coalescence of the aggregates; redispersing said toner in water at a pH of above about 7; contacting the resulting mixture with a metal halide or salt, and then with a mixture of an alkaline base and a salicylic acid, a catechol, or mixtures thereof at a temperature of from about 25.degree. C. to about 80.degree. C.; and optionally isolating the toner product, washing, and drying.
    Type: Grant
    Filed: January 13, 1998
    Date of Patent: February 9, 1999
    Assignee: Xerox Corporation
    Inventors: Beng S. Ong, Walter Mychajlowskij, Raj D. Patel, Patricia A. Burns, Richard P. N. Veregin
  • Patent number: 5869215
    Abstract: A process for the preparation of toner including(i) blending an aqueous colorant dispersion with a latex blend comprised of a linear polymer and a soft crosslinked polymer;(ii) heating the resulting mixture at about below, or about equal to the glass transition temperature (Tg) of the linear latex polymer to form aggregates; and(iii) subsequently heating said aggregate suspension about above, or about equal to the Tg of the linear latex polymer to effect fusion or coalescence of said aggregates.
    Type: Grant
    Filed: January 13, 1998
    Date of Patent: February 9, 1999
    Assignee: Xerox Corporation
    Inventors: Beng S. Ong, Walter Mychajlowskij, Patricia A. Burns, Raj D. Patel, David J. Sanders
  • Patent number: 5863698
    Abstract: A process for the preparation of toner comprising mixing a colorant containing a surfactant and a latex emulsion, and wherein the latex emulsion contains resin and a nonionic hydrolyzable surfactant, and wherein said surfactant is of the Formulas (I) or (II), or optionally mixtures thereof ##STR1## wherein R.sup.1 is a hydrophobic aliphatic, or hydrophobic aromatic group; R.sup.2 is selected from the group consisting of hydrogen, alkyl, aryl, alkylaryl, and alkylarylalkyl; R.sup.3 is hydrogen or alkyl; A is a hydrophilic polymer chain, and m represents the number of A segments; heating below about the resin latex glass transition temperature, followed by the addition of an anionic stabilizer, thereafter heating above about the resin glass transition temperature, and adjusting the pH of the resulting mixture of resin and colorant particles suspended in an aqueous phase containing anionic surfactant, cationic surfactant and nonionic hydrolyzable surfactant, wherein said pH is increased from about 1.
    Type: Grant
    Filed: April 13, 1998
    Date of Patent: January 26, 1999
    Assignee: Xerox Corporation
    Inventors: Raj D. Patel, Paul F. Smith, Beverly C. Dutoff, Nan-Xing Hu, Beng S. Ong, Michael A. Hopper
  • Patent number: 5858601
    Abstract: A process for the preparation of toner comprising(i) blending (a) a colorant dispersion containing a first ionic surfactant with (b) a latex emulsion comprised of an aqueous dispersion of core-shell polymer particles with a crosslinked polymer core and a linear polymer shell, and optional nonionic surfactant and a second ionic surfactant with a charge polarity opposite to that of said first ionic surfactant in said colorant dispersion;(ii) heating the resulting mixture at about below the glass transition temperature (Tg) of the linear latex shell polymer to form aggregates; and(iii) subsequently heating said aggregates about above the Tg of the linear latex shell polymer to effect coalescence and fusion of said aggregates.
    Type: Grant
    Filed: August 3, 1998
    Date of Patent: January 12, 1999
    Assignee: Xerox Corporation
    Inventors: Beng S. Ong, T. Hwee Ng, Walter Mychajlowskij, Raj D. Patel, Patricia A. Burns
  • Patent number: 5853944
    Abstract: A process for the preparation of toner with a first aggregation of sulfonated polyester, and thereafter a second aggregation with a colorant dispersion and an alkali halide.
    Type: Grant
    Filed: January 13, 1998
    Date of Patent: December 29, 1998
    Assignee: Xerox Corporation
    Inventors: Daniel A. Foucher, Raj D. Patel, Guerino G. Sacripante, Walter Mychajlowskij
  • Patent number: 5852140
    Abstract: Disclosed is a process for the preparation of a polymer which comprises effecting bulk polymerization of a mixture of at least one monomer, a free radical polymerization initiator, and a stable free radical agent until from about 10 to about 50 weight percent of the monomer has been polymerized; optionally adding additional free radical initiator; optionally adding a colorant; dispersing with a high shear mixer the aforementioned partially polymerized mixture in water containing a stabilizing component selected from the group consisting of non-ionic and ionic water soluble polymeric stabilizers to obtain a suspension of particles with an average diameter of from about 0.1 to about 10 microns; polymerizing the resulting suspension to form said polymer.
    Type: Grant
    Filed: March 25, 1993
    Date of Patent: December 22, 1998
    Assignee: Xerox Corporation
    Inventors: Michael K. Georges, Raj D. Patel
  • Patent number: 5840462
    Abstract: A process for the preparation of toner which involvesi) flushing a colorant into a sulfonated polyester resin;ii) mixing an organic soluble dye with the colorant polyester resin of i);iii) dispersing the resulting mixture into warm water thereby enabling the formation of submicron particles;iv) allowing the resulting solution to cool below about, or about equal to the glass transition temperature of said sulfonated polyester resin;v) adding an alkali halide solution and heating; and optionallyvi) recovering said toner, followed by washing and drying.
    Type: Grant
    Filed: January 13, 1998
    Date of Patent: November 24, 1998
    Assignee: Xerox Corporation
    Inventors: Daniel A. Foucher, Raj D. Patel, Guerino G. Sacripante, Grazyna E. Kmiecik-Lawrynowicz
  • Patent number: 5827633
    Abstract: A process for the preparation of toner comprising(i) preparing, or providing an aqueous colorant dispersion, which dispersion is comprised of a colorant and an ionic surfactant in water;(ii) blending said colorant dispersion with a latex emulsion comprised of resin particles, a nonionic surfactant, and an ionic surfactant of opposite charge polarity to that of the ionic surfactant in said colorant dispersion;(iii) heating the resulting mixture below about the glass transition temperature (Tg) of the latex resin to form toner sized aggregates;(iv) heating the resulting aggregate suspension of (iii) above about the Tg of the latex resin; and(v) retaining the temperature in the range of from about 30.degree. C. to about 95.degree. C.
    Type: Grant
    Filed: July 31, 1997
    Date of Patent: October 27, 1998
    Assignee: Xerox Corporation
    Inventors: Beng S. Ong, Raj D. Patel
  • Patent number: 5804349
    Abstract: A toner comprised of pigment, and an addition polymer resin generated from about 55 to about 80 weight percent of styrene, from about 1 to about 25 weight percent of acrylate, from about 1 to about 20 weight percent of acrylonitrile, and from about 0.5 to about 5 weight percent of acrylic acid.
    Type: Grant
    Filed: August 7, 1997
    Date of Patent: September 8, 1998
    Assignee: Xerox Corporation
    Inventors: Beng S. Ong, Grazyna E. Kmiecik-Lawrynowicz, Raj D. Patel, Walter Mychajlowskij, David J. Sanders, T. Hwee Ng
  • Patent number: 5766818
    Abstract: A process for the preparation of toner by mixing a colorant dispersion and a latex emulsion, and wherein the latex emulsion contains resin and a surfactant, wherein the surfactant is, for example, of the Formulas (I) or (II) ##STR1## wherein R.sup.1 is a hydrophobic aliphatic, or hydrophobic aromatic group; R.sup.2 is selected from the group consisting of hydrogen, alkyl, aryl, alkylaryl, and alkylarylalkyl; R.sup.3 is hydrogen or alkyl; A is a hydrophilic polymer, and m represents the number of A segments.
    Type: Grant
    Filed: October 29, 1997
    Date of Patent: June 16, 1998
    Assignee: Xerox Corporation
    Inventors: Paul F. Smith, Nan-Xing Hu, Beverly C. Dutoff, Beng S. Ong, Raj D. Patel, Michael A. Hopper
  • Patent number: 5763133
    Abstract: A process for the preparation of toner comprising(i) blending (a) an aqueous pigment dispersion containing a first ionic surfactant and an optional charge control agent with (b) a latex blend comprised of linear polymer and crosslinked polymer particles, optional nonionic surfactant and a second ionic surfactant with a charge polarity opposite to that of said first ionic surfactant in said pigment dispersion;(ii) heating the resulting mixture at about below the glass transition temperature (Tg) of the linear latex polymer to form toner sized aggregates; and(iii) subsequently heating said aggregate suspension about above the Tg of the linear latex polymer to effect fusion or coalescence of said aggregates.
    Type: Grant
    Filed: March 28, 1997
    Date of Patent: June 9, 1998
    Assignee: Xerox Corporation
    Inventors: Beng S. Ong, Walter Mychajlowskij, Grazyna E. Kmiecik-Lawrynowicz, Raj D. Patel, David J. Sanders, Stephan V. Drappel