Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Reexamination Certificate
2002-05-21
2004-01-20
Goodrow, John (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
C430S108100
Reexamination Certificate
active
06680153
ABSTRACT:
The present invention is generally directed to toner compositions and processes thereof, and more specifically, the present invention relates to a toner comprised of resin, colorant, and stabilizer, such as a UV stabilizer. More specifically, the present invention is directed to toner compositions comprised of resin particles, such as polyesters and colorant particles, and which colorant particles are generated from adding a UV stabilizer to a formed colorant, such as a pigment wet cake, or which stabilizer can be added, for example, when the nonstabilizer treated colorant is dispersed in the toner resin. The colorant with UV stabilizer can be dispersed in a resin, such as a polyester resin, or the dispersion can be purchased in this form from a number of suppliers, such as Sun Chemicals. It is believed, although not desiring to be limited by theory, that the UV stabilizer surrounds or coats the colorant and wherein the stabilizer functions to primarily protect the colorant from UV induced changes, and which changes can adversely affect the colorant properties, especially the toner color intensity, lightfastness of the colorant, and result in an undesirable modification of the colorant structure, and thus the color or intensity of the colorant, especially with respect to magenta colorants, such as Rhodamine YS, Pigment Red 81:2, the silicomolybdic acid salt of Rhodamine YS, and the like.
The toners of the present invention can be selected for known electrophotographic imaging methods, and printing processes, including color processes, digital methods, and lithography.
REFERENCES
Toners with colorants, such as magenta pigments, and toner additives such as charge additives are known. Patents which disclose colored toners with quaternary ammonium salts as charge control additives are U.S. Pat. Nos. 4,621,039; 4,560,635; 4,338,390 (Re. 32,883); 4,937,157; and 4,752,550, the disclosure of which is totally incorporated herein by reference. There is illustrated in U.S. Pat. No. 4,954,412, the disclosure of which is totally incorporated herein by reference, a microsuspension process for the preparation of encapsulated toner compositions comprised of an olefinic polymer core and a shell comprised of a thermotropic liquid crystalline polyester resin.
Polyester based chemical toners substantially free of encapsulation are also known, reference U.S. Pat. No. 5,593,807, the disclosure of which is totally incorporated herein by reference, wherein there is illustrated, for example, a process for the preparation of a toner comprised of a sodio sulfonated polyester resin and pigment, and wherein the aggregation and coalescence of resin particles can be accomplished in the presence of an alkali halide. Other U.S. patents that may be of interest, the disclosures of which are totally incorporated herein by reference, may be U.S. Pat. Nos. 5,853,944; 5,843,614; 5,840,462; 5,604,076; 5,648,193; 5,658,704 and 5,660,965.
The appropriate processes and components of the above patents may be selected for the present invention in embodiments thereof.
SUMMARY OF THE INVENTION
It is a feature of the present invention to provide dry toner compositions comprised of a resin or polymer, a stabilized colorant, and toner additives, such as waxes, charge additives, silica additives, metal salts or metal salts of fatty acids, metal oxides, mixtures thereof, and the like.
In another feature of the present invention there are provided colorant particles stabilized by a UV (ultra-violet light) stabilizer, or similar stabilizer.
In a further feature of the present invention there are provided toners with stabilized colorants and wherein the lightfastness of the colorant is excellent, the color gamut wide, the colorant intensity high and uniform, and wherein the stabilizer is included in the colorant dispersion thereby minimizing potential adverse effects, such as the triboelectric charge of the toner, admix characteristics of the toner, charge through, and enabling a lower cost toner in embodiments and further in embodiments wherein the toner resin can be easily crosslinked since, for example, the UV stabilizer or other effective suitable stabilizer are primarily present at or near the surface of the colorant and not primarily in the resin.
Additionally, in another feature of the present invention there are provided toners comprised of a resin and colorant, and wherein there is selected a stabilizer, such as a UV stabilizer, which possesses low or substantially no solubility in the toner polymer and which stabilizer can be dispersed in the colorant dispersion to thereby prevent, or minimize migration of the stabilizer into the toner resin.
Also, in another feature of the present invention there are provided surface-treated toner particles with excellent fusing characteristics for digital color printing applications, low fusing temperatures of from about 130° C. to about 150° C., high gloss performance measuring greater than about 40, such as from about 40 to about 90, gloss units as measured on a Gardner gloss metering unit, and low vinyl offset.
Moreover, in another feature of the present invention there are provided toner compositions, which can possess a spherical morphology, nonspherical morphology or mixtures thereof with an average particle volume diameter of from about 1 to about 25 microns, and preferably from about 6 to about 12 microns, and with a narrow GSD of from about 1.12 to about 1.30 as measured by a Coulter Counter.
Additionally, in another feature of the present invention there are provided toner compositions with a high projection efficiency, such as from about 75 to about 95 percent efficiency as measured by the Match Scan II spectrophotometer available from Milton-Roy.
In a further feature of the present invention there are provided toner compositions which result in minimal, low or no paper curl.
Aspects of the present application relate to a process for the preparation of a toner comprised of mixing a stabilized colorant dispersion with a resin, and wherein the stabilized colorant dispersion is generated from a mixture of a colorant dispersion and a stabilizer; a toner comprised of a resin and a colorant, and wherein the colorant is stabilized with a suitable stabilizer; a composition comprised of resin and colorant, and wherein the colorant is stabilized with an ultraviolet stabilizer or similar suitable stabilizer; a toner comprised of resin and colorant, and wherein the colorant is stabilized with a UV component and which stabilized colorant is generated by mixing a colorant dispersion with the UV component; a toner wherein the colorant is a cyan, black, magenta, or yellow dispersion or mixtures thereof with from about 20 to about 60 weight percent of colorant solids in the resin as a masterbatch; a toner wherein the colorant is carbon black; a toner wherein the colorant is a dye; a toner wherein the colorant is a pigment; a toner wherein the colorant is comprised of cyan, yellow, magenta, black, green, orange, violet or brown, and the like wherein each colorant is present in an amount of from about 2 weight percent to about 18 weight percent of the final toner composition; a toner wherein the toner contains blended dry powder additives on the toner surface, and which additives are, for example, comprised of metal salts, metal salts of fatty acids, colloidal silicas, metal oxides, coated silicas available from DeGussa Chemicals, and the like, or mixtures thereof, and which additives are each optionally present in an amount of from about 0.1 to about 8 weight percent; a toner wherein the resin is a polyester resin present in an amount of from about 80 to about 98 percent by weight of the final toner composition; a toner wherein the colorant is a cyan, black, magenta, or alternatively a yellow dispersion or mixtures thereof with from about 80 to about 98 weight percent solids of resin and colorant, and wherein the colorant is stabilized with a UV stabilizer, or wherein a stabilizer is present as a protective coating on the colorant; a toner wherein the colorant is comprised of a mixture of a
Gutman Edward J.
Hoffend Thomas R.
Silence Scott M.
Goodrow John
Palazzo E. D.
Xerox Corporation
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