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
2003-12-02
Chapman, Mark A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Process of making developer composition
Reexamination Certificate
active
06656657
ABSTRACT:
BACKGROUND
The present invention relates to toner processes, and more specifically, to a toner formed from a magnetite aggregation and coalescence processes. More specifically, the present invention in embodiments relates to processes for the preparation of a toner by a chemical process, such as emulsion aggregation, wherein the anionic latex particles selected are aggregated with the colorant particles, such as positively charged magnetite or iron oxides particles, and wherein the positive charge on the magnetite is induced by acidifying colorant dispersion, thus such particles can simultaneously function as colorant particles and as a flocculating or coagulating agent, and thereafter coalescing or fusing to provide toner size particles, which when developed by an electrographic process generates documents suitable for magnetic image character recognition or MICR. In particular, the anionic or the negatively charged latex, which possesses, for example, a pH of about 6.5 to about 7.5, is added to a magnetite dispersion which had been acidified to a pH value of, for example, about 2 to about 2.4 with an acid, thereby inducing a positive charge of about +50 to about +25 coulombs/cm
2
on the magnetite particles. To the resulting mixture is then added an anionic carbon black dispersion resulting in a mixture of resin, magnetite, wax and carbon black particles suspended in water in the presence of an anionic surfactant, followed by acidifying the blend to a pH of about 2.2 to about 2.6, and followed by aggregation and coalescence.
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.
With respect to the references, only a small part thereof has been selected and this part may or may not be fully representative of the prior art teachings or disclosures.
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 contains, for example, magnetic particles, such as 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 including magnetic particles permitting 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.
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 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 involved is referred to as MICR characters, which characters appear, for example, at the bottom of personal checks as printed numbers and symbols. These checks have been printed with 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. The second field contains the account affected by the transactions, and the third field, which is not be prerecorded indicates the amount of the check.
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 in the formulation 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 the preparation of MICR toners by melt mixing the appropriate components in a Banbury apparatus, following by pulverizing the magnetite and the resin, and then jetting and classifying to provide, for example, about 10 to about 12 micron toner size particles, which when mixed with an additive package and carrier can provide a developer suitable for the Xerox Corporation 9700®.
Other patents relating to MICR processes include U.S. Pat. Nos. 4,859,550; 5,510,221, and 5,034,298, the disclosure of which is totally incorporated herein by reference.
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.
Illustrated in U.S. Pat. No. 4,758,506, the disclosure of which is totally incorporated herein by reference, are single component development cold pressure fixable toner compositions, wherein the shell selected can be prepared by an interfacial polymerization process. Also known are single component magnetic cold pressure fixable toner compositions comprised of magnetite and a polyisobutylene encapsulated in a polymeric shell material generated by an interfacial polymerization process.
In situations requiring MICR capabilities, the toners selected should 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 remaining whe
Bartel Joseph
Hopper Michael A.
Patel Raj D.
Zwartz Edward G.
Chapman Mark A.
Palazzo E. D.
Xerox Corporation
LandOfFree
Toner processes does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Toner processes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Toner processes will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3168133