Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Process of making developer composition
Reexamination Certificate
2003-01-29
2004-07-27
Goodrow, John L (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Process of making developer composition
C430S109100, C523S334000
Reexamination Certificate
active
06767684
ABSTRACT:
The appropriate components, such as for example, magnetites, waxes, coagulants, resin latexes, surfactants, and colorants, and processes of the above copending applications may be selected for the present invention in embodiments thereof.
BACKGROUND
This invention relates to toner processes, and more specifically, to aggregation and coalescence processes. More specifically, the present invention relates in embodiments to methods for the preparation of toner compositions by a chemical process, such as emulsion aggregation wherein latex particles are aggregated with a wax, a crosslinked gel, colorants, and a magnetite in the presence of a coagulant like a polymetal halide, or alternatively a mixture of coagulants, thereafter coalescing to provide toner particles which when developed by an electrographic process generates documents suitable for magnetic image character recognition or MICR.
A number of advantages are associated with the present invention in embodiments thereof including, for example, excellent hot offset, for example above about 210° C., and more specifically, from about 210° C. to about 230° C.; a fusing latitude of from about 20° C. to about 35° C., wherein fusing latitude refers to a temperature in which, when a developed image is fused, evidences no offset either to the substrate that the image is fused on, referred as “Cold” offset or an offset on the fuser roll referred as the “HOT” offset; a minimum fixing temperature of, for example, about 170° C. to about 195° C.; and extended photoreceptor life since the toner fusing temperature can be below about 195° C., such as from about 175° C. to about 190° C., as measured.
REFERENCES
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 a coagulant, followed by aggregation and coalescence, wherein the coagulant may be a 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 a coagulant, followed by aggregation and coalescence, wherein the coagulant may be a polyaluminum sulfosilicate.
Illustrated in U.S. Pat. No. 5,994,020, the disclosure of which is totally incorporated herein by reference, are toner preparation 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.
Magnetic ink printing methods with inks containing magnetic particles are known. For example, there is disclosed in U.S. Pat. No. 3,998,160, the disclosure of which is totally incorporated herein by reference, that various magnetic inks have been used in printing digits, characters, or artistic designs on checks or bank notes. The magnetic ink used for these processes can contain, for example, acicular magnetic particles, such as a magnetite in a fluid medium, and a magnetic coating of ferric oxide, chromium dioxide, or similar materials dispersed in a vehicle comprising binders, and plasticizers. According to the disclosure of the '160 patent, there is provided a method of printing on a surface with an ink containing acicular magnetic particles in order that the authenticity of the printing can be verified, and wherein a pattern is formed on a carrier with the ink in the wet state, and wherein the particles are subjected to a magnetic aligning process while the ink is on the carrier. Subsequently, the wet ink is transferred to the surface, which transfer is accomplished with substantially aligned particles.
Disclosed in U.S. Pat. No. 4,128,202, the disclosure of which is totally incorporated herein by reference, is a device for transporting a document that has been mutilated or erroneously encoded and wherein there is provided a predetermined area for the receipt of correctly encoded magnetic image character recognition information (MICR). As indicated in this patent, the information is referred to as MICR characters, which characters can appear, for example, at the bottom of personal checks as printed numbers and symbols. These checks have been printed in an ink containing magnetizable particles therein, and when the information contained on the document is to be read, the document is passed through a sorter/reader which first magnetizes the magnetizable particles, and subsequently detects a magnetic field of the symbols resulting from the magnetic retentivity of the ink. The characters and symbols involved, according to the '202 patent, are generally segregated into three separate fields, the first field being termed a transient field, which contains the appropriate symbols and characters to identify the bank, bank branch, or the issuing source.
In U.S. Pat. No. 5,914,209, the disclosure of which is totally incorporated by reference, there is illustrated a process for preparing MICR toners using a combination of hard and soft magnetites, and lubricating wax and melt mixing with a resin followed by jetting and classifying the blend to provide toner compositions.
In U.S. Pat. No. 4,517,268, the disclosure of which is totally incorporated by reference, there is illustrated a process for preparing MICR toners using styrene copolymers, such as styrene butadiene, in the absence of a lubricating wax by melt mixing in a Banbury apparatus, followed by pulverizing the magnetite and the resin, followed by jetting and classifying to provide, for example, 10 to 12 micron toner size particles which when mixed with an additive package and a carrier provides a developer suitable for using in the Xerox Corporation 9700®.
Further patents relating to MICR processes are U.S. Pat. Nos. 4,859,550; 5,510,221; and 5,034,298, all illustrating, for example, the generation of MICR toners by conventional means such as that described in U.S. Pat. No. 4,517,268.
In U.S. Pat. No. 5,780,190, the disclosure of which is totally incorporated herein by reference, there is disclosed an ionographic process which comprises the generation of a latent image comprised of characters; developing the image with an encapsulated magnetic toner comprised of a core comprised of a polymer and soft magnetite, and wherein the core is encapsulated within a polymeric shell; and subsequently providing the developed image with magnetic ink characters thereon to a reader/sorter device.
In applications requiring MICR capabilities, the toners selected usually contain magnetites having specific properties, an important one of which is a high enough level of remanence or retentivity. Retentivity is a measure of the magnetism left when the magnetite is removed from the magnetic field, i.e., the residual magnetism. Also of value are toners with a high enough retentivity, such that when the characters are read, the magnetites produce a signal strength of equal to greater than about 100 percent. The signal level can vary in proportion to the amount of toner deposited on the document being generated. The signal strength of a toner composition can be measured by using known devices, including the MICR-
Chen Allan K.
Hopper Michael A.
Patel Raj D.
Zwartz Edward G.
Goodrow John L
Palazzo E. O.
Xerox Corporation
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