Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Process of making developer composition
Reexamination Certificate
2001-09-24
2003-05-13
Rodee, Christopher (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Process of making developer composition
C523S335000
Reexamination Certificate
active
06562541
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to a toner process, and more specifically, to chemical toner processes which involve the aggregation and fusion of latex, colorant like pigment or dye, and additive particles into toner particles. More specifically, in embodiments the present invention relates to toner processes wherein there is selected a fluoropolymer wherein the fluoropolymer (PTFE) is comprised, for example, of submicron anionic colloidal stabilized particles which when incorporated in the host resin of, for example, styrene butylacrylate beta carboxyl ethyl acrylate result in reducing the gloss levels of the image developed and provide an improvement in the hot offset temperature, thereby increasing the fusing latitude, wherein the fusing latitude is the temperature difference of the cold offset and the hot offset temperature where the greater the difference the larger the fusing latitude. The fusing latitude is also dependent on the type of fuser and the subsystems employed.
The incorporation of the colloidal, for example about 40 to about 125, about 75 to about 100, and more specifically, about 80 nanometers in diameter, fluoropolymer allows for a reduction of the gloss of the image developed to a matte finish wherein, for example, generally the greater the amount of incorporation of the fluoropolymer the greater the reduction in gloss of the image developed and the higher the hot offset temperature.
The toners generated with the processes of the present invention can be selected for copy and printing processes, including color processes and for imaging processes, especially xerographic processes, which usually desire a toner transfer efficiency of about 90 percent, such as those with a compact machine design without a cleaner or those that are designed to provide high quality colored images with excellent image resolution, acceptable signal-to-noise ratio, and image uniformity. Also, the toners obtained with the processes illustrated herein can be selected for digital imaging systems and processes.
PRIOR ART
In xerographic systems, especially color systems, small sized toners of, for example, from about 2 to about 8 microns can be important to the achievement of high image quality for process color applications. It is also important 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, it may be useful to select certain toner particle sizes, such as from about 2 to about 10 microns, 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 loadings often adversely affect the charging behavior of toners. For example, the charge levels may be too low for proper toner development or the charge distributions may be too wide and toners of wrong charge polarity may be present. Furthermore, higher pigment loadings may also result in the sensitivity of charging behavior to charges in environmental conditions such as temperature and humidity. Toners prepared in accordance with the processes of the present invention minimize, or avoid these disadvantages.
There is illustrated in U.S. Pat. No. 4,996,127 a toner of associated particles of secondary particles comprising primary particles of a polymer having acidic or basic polar groups and a coloring agent. The polymers selected for the toners of the '127 patent can be prepared by an emulsion polymerization method, see for example columns 4 and 5 of this patent. In column 7 of this '127 patent, it is indicated that the toner can be prepared by mixing the required amount of coloring agent and optional charge additive with an emulsion of the polymer having an acidic or basic polar group obtained by emulsion polymerization. In U.S. Pat. No. 4,983,488, there is disclosed a process for the preparation of toners by the polymerization of a polymerizable monomer dispersed by emulsification in the presence of a colorant and/or a magnetic powder to prepare a principal resin component and then effecting coagulation of the resulting polymerization liquid in such a manner that the particles in the liquid after coagulation have diameters suitable for a toner. It is indicated in column 9 of this patent that coagulated particles of 1 to 100, and particularly 3 to 70 microns, are obtained. This process results, it is believed, in the formation of particles with a wide particle size distribution. Similarly, the aforementioned disadvantages, for example poor particle size distributions, are obtained hence classification is required resulting in low toner yields, are illustrated in other prior art, such as U.S. Pat. No. 4,797,339, wherein there is disclosed a process for the preparation of toners by resin emulsion polymerization, wherein similar to the '127 patent certain polar resins are selected; and U.S. Pat. No. 4,558,108, wherein there is disclosed a process for the preparation of a copolymer of styrene and butadiene by specific suspension polymerization. Other prior art includes U.S. Pat. Nos. 3,674,736;4,137,188 and 5,066,560.
Emulsion/aggregation/coalescence processes for the preparation of toners are illustrated in a number of Xerox patents, the disclosures of each of which are totally incorporated herein by reference, such as U.S. Pat. No. 5,290,654, U.S. Pat. No. 5,278,020, U.S. Pat. No. 5,308,734, U.S. Pat. No. 5,370,963, U.S. Pat. No. 5,344,738, U.S. Pat. No. 5,403,693, U.S. Pat. No. 5,418,108, U.S. Pat. No. 5,364,729, and U.S. Pat. No. 5,346,797; and also of interest may be U.S. Pat. Nos. 5,348,832; 5,405,728; 5,366,841; 5,496,676; 5,527,658; 5,585,215; 5,650,255; 5,650,256 and 5,501,935; 5,723,253; 5,744,520; 5,763,133; 5,766,818; 5,747,215; 5,827,633; 5,853,944; 5,804,349; 5,840,462; 5,869,215; 5,863,698; 5,902,710; 5,910,387; 5,916,725; 5,919,595; 5,925,488 and 5,977,210. The appropriate components and processes of the above Xerox Corporation patents can be selected for the processes of the present invention in embodiments thereof.
With respect to the prior art, 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.
SUMMARY OF THE INVENTION
It is a feature of the present invention to provide toner processes with many of the advantages illustrated herein.
In another feature of the present invention there are provided simple and economical processes for the preparation of black and colored toner compositions with excellent colorant dispersions, thus enabling the achievement of excellent color print quality and providing similar charging behavior despite differential colorant chemistry, and wherein the selection of the colloidal fluoropolymer particles in the host rest functions as a filler where the gloss is reduced due to differential melt temperatures of the host resin and the filler, which resin, for example, possesses a melt temperatu
Drappel Stephan V.
Hopper Michael A.
Patel Raj D.
Vanbesien Daryl
Palazzo E. O.
Rodee Christopher
Xerox Corporation
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