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US5153092A Expired / Lapsed US ⏱️ 0.0 years remaining

Processes for encapsulated toners

Assignee: Xerox Corp
•
Filing: 1991-01-28
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Granted: 1992-10-06
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Expires: 2011-01-28
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Abstract

Abstract A process for the preparation of encapsulated toners which comprises blending core momomer or monomers, free radical initiator, pigment, and an oil soluble shell monomer; dispersing the resulting mixture in a stabilized aqueous suspension; thereafter subjecting the stabilized droplets to a shell forming interfacial polycondensation reaction by adding a water soluble shell monomer or monomers; subsequently forming the core resin binder by heat induced free radical polymerization within the newly formed capsules; washing the toner suspension; subsequently removing water therefrom in a fluidized bed dryer to obtain a dry encapsulated toner with a surface moisture content of about 0.3 percent by weight to about 0.8 percent by weight; and thereafter blending the encapsulated toner with surface additives.

Inventors

  • 👤 Sheau V. Kao
  • 👤 Gerald R. Allison
  • 👤 Michael S. Hawkins
  • 👤 Hadi K. Mahabadi

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-27 11:24
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/093; G03G9/09307; G03G9/09335; G03G9/0935; G03G9/09357; G03G9/09364; G03G9/09392

Claims Analysis

Total Claims: 30
Claim 1
Independent Claim 117 words
A process for the preparation of encapsulated toners which comprises blending core momomer or monomers, free radical initiator, pigment, and an oil soluble shell monomer; dispersing the resulting mixture in a stabilized aqueous suspension; thereafter subjecting the stabilized droplets to a shell forming interfacial polycondensation reaction by adding a water soluble shell monomer or monomers; subsequently forming the core resin binder by heat induced free radical polymerization within the newly formed capsules; washing the toner suspension; subsequently removing water therefrom in a fluidized bed dryer to obtain a dry encapsulated toner with a surface moisture content of about 0.3 percent by weight to about 0.8 percent by weight; and thereafter blending the encapsulated toner with surface additives.
Claim 2
Dependent Claim 117 words
A process for the preparation of encapsulated toners which comprises blending core momomer or monomers, free radical initiator, pigment, and an oil soluble shell monomer; dispersing the resulting mixture in a stabilized aqueous suspension; thereafter subjecting the stabilized droplets to a shell forming interfacial polycondensation reaction by adding a water soluble shell monomer or monomers; subsequently forming the core resin binder by heat induced free radical polymerization within the newly formed capsules; washing the toner suspension; subsequently removing water therefrom in a fluidized bed dryer to obtain a dry encapsulated toner with a surface moisture content of about 0.3 percent by weight to about 0.8 percent by weight; and thereafter blending the encapsulated toner with surface additives.
Claim 3
Dependent Claim 24 words
A process in accordance with claim 1 wherein the surface additives are comprised of carbon black and a metal salt of a fatty acid.
Claim 4
Dependent Claim 18 words
A process in accordance with claim 2 wherein the metal salt of a fatty acid is zinc stearate.
Claim 5
Dependent Claim 22 words
A process in accordance with claim 2 wherein the carbon black and a metal salt of a fatty acid are added sequentially.
Claim 6
Dependent Claim 14 words
A process in accordance with claim 4 wherein a conductive carbon black is selected.
Claim 7
Dependent Claim 27 words
A process in accordance with claim 1 wherein the surface additives are comprised of carbon black, a metal salt of a fatty acid and a release component.
Claim 8
Dependent Claim 25 words
A process in accordance with claim 6 wherein the carbon black, the metal salt of a fatty acid, and the release component are added sequentially.
Claim 9
Dependent Claim 28 words
A process in accordance with claim 1 wherein the water is removed in a fluidized bed dryer in a period of from about 10 to about 20 minutes.
Claim 10
Dependent Claim 19 words
A process in accordance with claim 1 wherein the shell is pressure rupturable and the core is pressure fixable.
Claim 11
Dependent Claim 44 words
A process in accordance with claim 1 wherein the fluidized bed dryer comprises an air distribution device, a product container, an expansion chamber and filter bags, and a means to heat the entering air to facilitate the removal of water from the toner particles.
Claim 12
Dependent Claim 56 words
A process in accordance with claim 1 wherein the blending is accomplished in a mixer with an agitating impeller/chopper speed of from about 2,000 to about 5,000 revolutions per minute, a peripheral speed of from about 0.8 meter/second to about 3.0 meters/second, and a tumbling/plowing speed of from about 10 to about 200 revolutions per minute.
Claim 13
Dependent Claim 23 words
A process in accordance with claim 1 wherein the toner conductivity is from about 10 -8 to about 10 -2 ohm-cm -1 .
Claim 14
Dependent Claim 18 words
A process in accordance with claim 12 wherein one of the surface additives is a conductive carbon black.
Claim 15
Dependent Claim 63 words
A process in accordance with claim 13 wherein the conductive carbon black is present in an amount of from about 0.2 to about 2 percent by weight, and is blended in the toner a period of time of from about 1 minute to about 5 minutes in a mixer at an agitation speed of from about 3,000 to about 5,000 revolutions per minute.
Claim 16
Dependent Claim 23 words
A process in accordance with claim 13 wherein the toner volume resistivity thereof is from about 1×10 3 to about 1×10 8 ohm-cm.
Claim 17
Dependent Claim 25 words
A process in accordance with claim 15 wherein the toner resistivity remains unchanged subsequent to agitation at a mixing speed of 1,500 revolutions per minute.
Claim 18
Dependent Claim 31 words
A process in accordance with claim 1 wherein one of the surface additives is a release agent selected from the group consisting of metal salts of fatty acids and colloidal silicas.
Claim 19
Dependent Claim 12 words
A process in accordance with claim 17 wherein zinc stearate is selected.
Claim 20
Dependent Claim 62 words
A process in accordance with claim 18 wherein the zinc stearate is present in an amount of from about 0.5 to about 5 percent by weight, and is blended in the toner a period of time of from about 5 minutes to about 50 minutes in a mixer at an agitation speed of from about 2,000 to about 5,000 revolutions per minute.
Claim 21
Dependent Claim 60 words
A process in accordance with claim 19 wherein the toner resistivity increases rapidly from about 1×10 2 to 5×10 3 ohm-cm to about 1×10 4 to 1×10 5 ohm-cm following the addition of zinc stearate, and retained a resistivity of from 1×10 4 to 1×10 5 ohm-cm during blending and subsequently increased to about 1×10 5 to 1×10 8 ohm-cm.
Claim 22
Dependent Claim 26 words
A process in accordance with claim 1 wherein the surface additives are present in an amount of from about 0.05 to about 5 percent by weight.
Claim 23
Dependent Claim 17 words
A process in accordance with claim 1 wherein one surface additive comprised of carbon black is selected.
Claim 24
Dependent Claim 26 words
A process in accordance with claim 1 wherein the polymeric shell is a polyurea, a polyurethane, a polyamide, a polyester, or a liquid crystalline thermotropic polymer.
Claim 25
Dependent Claim 90 words
A process in accordance with claim 1 wherein the core monomer for formation of the core polymer is selected from the group consisting of n-butyl acrylate, s-butyl acrylate, isobutyl acrylate, butyl methacrylate, s-butyl methacrylate, isobutyl methacrylate, benzyl acrylate, benzyl methacrylate, propyl acrylate, isopropyl acrylate, hexyl acrylate, cyclohexyl acrylate, hexyl methacrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, pentyl acrylate, pentyl methacrylate, stearyl acrylate, stearyl methacrylate, ethoxypropyl acrylate, ethoxypropyl methacrylate, heptyl acrylate, heptyl methacrylate, methylbutyl acrylate, methylbutyl methacrylate, m-tolyl acrylate, styrene, dodecyl styrene, hexylmethyl styrene, nonyl styrene, tetradecyl styrene, and mixtures thereof.
Claim 26
Dependent Claim 24 words
A process in accordance with claim 1 wherein water is removed by heating at a temperature of from about 50° to about 200° C.
Claim 27
Dependent Claim 33 words
A process in accordance with claim 1 wherein subsequent to washing a quantity of water is removed to enable toner cakes with from about 5 to about 15 percent by weight of water.
Claim 28
Dependent Claim 17 words
A process in accordance with claim 26 wherein removal of water or dewatering is accomplished by centrifugation.
Claim 29
Dependent Claim 17 words
A process in accordance with claim 1 wherein the pigment is carbon black, magnetite, or mixtures thereof.
Claim 30
Dependent Claim 70 words
A process in accordance with claim 1 wherein the pigment is selected from the group consisting of Heliogen Blue, Pylam Oil Blue, Pylam Oil Yellow, Pigment Blue, Pigment Violet, Pigment Red, Lemon Chrome Yellow, Bon Red, NOVAperm, Yellow FGL, Hostaperm Pink, 2,9-dimethyl-substituted quinacridone, Dispersed Red, Solvent Red, copper tetra-(octadecyl sulfonamido) phthalocyanine, copper phthalocyanine, diarylide yellow 3,3-dichlorobenzidene acetoacetanilides, a nitrophenyl amine sulfonamide, Dispersed yellow 2,5-dimethoxy-4-sulfonanilide phenylazo-4'-chloro-2,5-dimethoxy acetoacetanilide, and Permanent Yellow FGL.

References Cited (Backward Citations)

US4272010A Cited
US4699866A Cited
US4599294A Cited
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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1995-10-06 1996-04-06 1996-10-06 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1999-10-06 2000-04-06 2000-10-06 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2003-10-06 2004-04-06 2004-10-06 $7700.00 Window Closed / Lapsed

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