Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Process of making developer composition
Reexamination Certificate
2002-03-25
2004-01-06
Rodee, Christopher (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Process of making developer composition
C523S333000, C523S335000
Reexamination Certificate
active
06673505
ABSTRACT:
COPENDING APPLICATIONS AND PATENTS
Illustrated in U.S. Pat. No. 6,495,302, filed Jun. 11, 2001 on Toner Coagulant Processes; U.S. Pat. No. 6,416,920, filed Mar. 19, 2001 on Toner Coagulant Processes; U.S. Pat. No. 6,500,597, filed Aug. 6, 2001 on Toner Coagulant Processes; U.S. Pat. No. 6,562,541, filed Sep. 24, 2001 on Toner Processes; and U.S. Pat. No. 6,576,389, filed Oct. 15, 2001 on Toner Coagulant Processes, the disclosures of which are totally incorporated herein by reference, are toner processes wherein a coagulant may be selected.
In U.S. Pat. No. 6,132,924, the disclosure of which is totally incorporated herein by reference, there is illustrated a process for the preparation of toner comprising mixing a colorant, a latex, and two coagulants, followed by aggregation and coalescence and wherein one of the coagulants may be polyaluminum chloride.
In U.S. Pat. No. 6,268,102, the disclosure of which is totally incorporated herein by reference, there is illustrated a process for the preparation of toner comprising mixing a colorant, a latex, and two coagulants, followed by aggregation and coalescence and wherein one of the coagulants is a poly aluminum sulfosilicate.
In copending patent application U.S. Ser. No. 08/922,437, now abandoned, the disclosure of which is totally incorporated herein by reference, there is illustrated, for example, a process for the preparation of toner comprising
(i) aggregating with a metal complex, or metal ion a colorant dispersion with a latex emulsion and optional additives to form aggregates;
(ii) coalescing or fusing the aggregates; and optionally
(iii) isolating, washing, and drying the toner.
In U.S. Pat. No. 6,352,810, the disclosure of which is totally incorporated herein by reference, is illustrated, for example, a process of preparing a toner comprising
(i) aggregating with a coagulant of a polyamine salt, a colorant, dispersion with a latex emulsion and optional additives to form aggregates followed by optionally adding a second latex emulsion to the formed aggregates;
(ii) adding an oxidizing agent to remove the excess coagulant followed by a changing the pH with a base, heating to coalesce or fuse the aggregates;
(iii) lowering the pH to accelerate the coalescence process and optionally isolating, washing and drying the toner.
Illustrated in U.S. Pat. No. 5,994,020, the disclosure of which are totally incorporated herein by reference, are toner processes, and more specifically, a process for the preparation of toner comprising
(i) preparing, or providing a colorant dispersion;
(ii) preparing, or providing a functionalized wax dispersion comprised of a functionalized wax contained in a dispersant mixture comprised of a nonionic surfactant, an ionic surfactant, or mixtures thereof;
(iii) shearing the resulting mixture of the functionalized wax dispersion (ii) and the colorant dispersion (i) with a latex or emulsion blend comprised of resin contained in a mixture of an anionic surfactant and a nonionic surfactant;
(iv) heating the resulting sheared blend of (iii) below about the glass transition temperature (Tg) of the resin particles;
(v) optionally adding additional anionic surfactant to the resulting aggregated suspension of (iv) to prevent, or minimize additional particle growth of the resulting electrostatically bound toner size aggregates during coalescence (iv);
(vi) heating the resulting mixture of (v) above about the Tg of the resin; and optionally,
(vii) separating the toner particles; and a process for the preparation of toner comprising blending a latex emulsion containing resin, colorant, and a polymeric additive; adding an acid to achieve a pH of about 2 to about 4 for the resulting mixture; heating at a temperature about equal to, or about below the glass transition temperature (Tg) of the latex resin; optionally adding an ionic surfactant stabilizer; heating at a temperature about equal to, or above about the Tg of the latex resin; and optionally cooling, isolating, washing, and drying the toner.
The appropriate components and processes of the above recited copending applications and patent may be selected for the processes of the present invention in embodiments thereof.
BACKGROUND
The present invention is directed to processes, and more specifically, to chemical toner processes which involve the aggregation of a latex, colorant like pigment, or dye, and additive particles followed by the fusion of the aggregates into toner particles, and wherein aggregation can be primarily controlled by utilizing a coagulant of a polyamine salt comprising, for example, salts obtained by reacting tri(2-aminoethyl) citrate with an acid, and wherein there is more specifically selected a latex comprised of, for example, submicron resin particles of about 0.1 to about 0.4 micron in volume average diameter, suspended in an aqueous phase of water, and an anionic surfactant, and optionally a nonionic to which is added a colorant dispersion comprising, for example, submicron colorant particles of, for example, about 0.08 to about 0.3 micron in volume average diameter, anionic surfactant, or optionally a nonionic surfactant, or a mixture of both, anionic and a nonionic surfactant comprising, for example, from about 40:60 to about 60:40 weight percent mixtures of anionic to nonionic surfactant thereof, and optionally adding a wax dispersion comprising submicron wax particles of a size of, for example, about 0.1 to about 0.3 micron in volume average diameter suspended in an aqueous phase of water and an anionic surfactant, and wherein the resultant blend is stirred and heated to a temperature below the resin Tg, resulting in aggregates to which optionally is added a second latex, followed by adjusting the pH of the mixture with a base to neutralize the amine salt thereby converting the amine to an amide or hydrolyzing the amine to an acid thereby preventing or minimizing the formation of new cations or salts being generated during the coalescence, followed by heating the mixture to a temperature above the resin Tg, then lowering the pH of the mixture with an acid to fuse the aggregates.
The toners generated with the processes of the present invention are especially useful for imaging processes, especially xerographic processes, digital imaging processes, color processes and the like.
REFERENCES
In xerographic systems, especially color systems, small sized toners of from about 2 to about 8 microns can be important to the achievement of high image quality for process color applications. It is also of value to have a low image pile height to eliminate, or minimize image feel and avoid paper curling after fusing. Paper curling can be particularly pronounced in xerographic color processes primarily because of the presence of relatively high toner coverage as a result of the application of three to four color toners. During fusing moisture escapes from the paper due to high fusing temperatures of from about 120° C. to about 200° C. In the situation wherein only one layer of toner is selected, such as in one-color black or highlight color xerographic applications, the amount of moisture driven off during fusing can be reabsorbed by the paper and the resulting print remains relatively flat with minimal paper curl. In process color where toner coverage is high, the relatively thick toner plastic covering on the paper can inhibit the paper from reabsorbing the moisture, and cause substantial paper curling. These and other imaging shortfalls and problems are avoided or minimized with the toners and processes of the present invention.
Also, one can select certain toner particle sizes, such as from about 2 to about 10 microns, and with a high colorant, especially pigment loading such as from about 4 to about 15 percent by weight of toner, so that the mass of toner necessary for attaining the required optical density and color gamut can be significantly reduced to eliminate or minimize paper curl. Lower toner mass also ensures the achievement of image uniformity. However, higher pigment loading often adversely affects the charging behavior of toners. For e
Cheng Chieh-Min
Hopper Michael A.
Jiang Lu
Mychajlowskij Walter
Patel Raj D.
Palazzo E. D.
Rodee Christopher
Xerox Corporation
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