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US4287281A Expired / Lapsed US ⏱️ 0.0 years remaining

Magnetic toner composition and a method of making the same

Assignee: Xerox Corp
•
Filing: 1979-10-22
•
Granted: 1981-09-01
•
Expires: 1999-10-22
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Abstract

Abstract Magnetic toner compositions are prepared using two types of magnetic particles. The first type of magnetic particles have hydrophilic surface characteristics and the second type of magnetic particles have hydrophobic surface characteristics. Toner compositions are prepared by a dispersion polymerization technique wherein both types of magnetic pigment are dispersed in a vinyl monomer containing a polymerization initiator. This mixture of materials forms the discontinuous phase of a dispersion polymerization, the continuous phase being water containing a suspension stabilizing agent. The toner particles thus formed have the hydrophilic magnetic particles distributed on or near the surface of the toner particles while the hydrophobic magnetic particles are uniformly distributed throughout the remainder of the toner particles.

Inventors

  • 👤 Robert D. Bayley

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-27 22:00
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/083; G03G9/0839

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 39 words
A magnetic toner composition comprising particles, said particles comprising resin and magnetic particles dispersed within the resin, said magnetic particles being of two types, the first type having hydrophilic surface characteristics and the second type having hydrophobic surface characteristics.
Claim 2
Dependent Claim 39 words
A magnetic toner composition comprising particles, said particles comprising resin and magnetic particles dispersed within the resin, said magnetic particles being of two types, the first type having hydrophilic surface characteristics and the second type having hydrophobic surface characteristics.
Claim 3
Dependent Claim 33 words
The magnetic toner composition of claim 1 wherein the ratio by weight of the first type hydrophilic magnetic particles to the second type hydrophobic magnetic particles is from about 5:95 to about 95:5.
Claim 4
Dependent Claim 17 words
The magnetic toner composition of claim 2 wherein the ratio is from about 5:95 to about 35:65.
Claim 5
Dependent Claim 37 words
The magnetic toner composition of claims 1 or 3 wherein the total concentration of magnetic particles in the toner composition is from about 40 to about 75 percent by weight based on the weight of the resin.
Claim 6
Dependent Claim 37 words
The magnetic toner composition of claims 1 or 3 wherein the total concentration of magnetic particles in the toner composition is from about 45 to about 55 percent by weight based on the weight of the resin.
Claim 7
Dependent Claim 20 words
The magnetic toner composition of claim 1 wherein the first type magnetic particles having hydrophilic surface characteristics is uncoated magnetite.
Claim 8
Dependent Claim 24 words
The magnetic toner composition of claim 1 wherein the second type magnetic particles having hydrophobic surface characteristics is magnetite coated with a hydrophobic agent.
Claim 9
Dependent Claim 45 words
The magnetic toner composition of claim 1 wherein the first type magnetic particles having hydrophilic surface characteristics are located near the surface of the toner particles and the second type magnetic particles having hydrophobic surface characteristics are uniformly distributed throughout the remainder of the particles.

References Cited (Backward Citations)

US3080318A Cited
US3093039A Cited
US3345294A Cited
US3796664A Cited
US3959153A Cited
DE2538112A1 Cited
US4071670A Cited
US4097620A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1984-08-31 1985-03-02 1985-09-01 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1988-08-31 1989-03-02 1989-09-01 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1992-08-31 1993-03-02 1993-09-01 $7700.00 Window Closed / Lapsed

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