Coated carriers

Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...

Reexamination Certificate

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C430S137130

Reexamination Certificate

active

06423461

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention is generally directed to developer compositions, and more specifically, the present invention relates to developer compositions with conductive coated carrier components, or coated carrier particles that can be prepared by, for example, dry powder processes. More specifically, the present invention relates to compositions, especially carrier compositions comprised of a core, and thereover a blend or mixture of polymers comprised of an organic, like an organometallic containing polymer, or polymers, an inorganic polymer or inorganic polymers and further polymers, that is, for example, a plurality of polymers, such as 1 to about 10, and more specifically, from about 1 to about 3.
In embodiments of the present invention, the carrier particles are comprised of a core with a coating blend thereover, such as an organometallic ferrocene containing polymer such as a poly(ferrocenyl silane), a poly(ferrocenyl phosphane), or more specifically, poly(ferrocenyl dialkyl silane), such as dimethylsilane or poly(ferrocenyl aryl, such as ferrocenyl phenylphosphane), and an inorganic polymer of, for example, a polysiloxane containing conductive pendant groups, a polyphosphazene of poly(bis(methoxyethoxyethoxy)phosphazene of (1), poly(phenyl(methoxyethoxyethoxy)phosphazene (2); poly(methyl(methoxyethoxyethoxy)phosphazene (3); poly(methoxy(methoxyethoxyethoxy)phosphazene (4); poly(phenoxy(methoxyethoxy ethoxy)phosphazene (5); poly(methylamino(methoxyethoxyethoxy)phosphazene (6); poly(phenylamino(methoxyethoxyethoxy)phosphazene (7); poly(bis(methoxyethoxy)phosphazene (8); poly(bis(methoxypropoxy)phosphazene (9); poly(bis-&bgr;-pentafluroethylpropoxy)phosphazene (10); poly(bisphenoxy)phosphazene (11); poly(bis-&bgr;-trifluoromethylethoxy)phosphazene (12); poly(bis-4-phenylphenoxy)phosphazene (13); poly(bis[1,1]biphenyl-4-methoxy-4′-ethoxyethoxyethoxy)phosphazene (14); or poly(bismethoxy)phosphazene (15); a carrier wherein the conductive polymer is a polyphosphazene of poly[bis-4-isopropylphenoxy)phosphazene] (16); poly(2-methoxyethoxyethoxycarbo-4,4-methoxyethoxyethoxy-6,6-methoxyethoxyethoxy)phosphazene (17); poly(2-methoxyethoxyethoxy-thio-4,4-methoxyethoxyethoxy-6,6-methoxyethoxyethoxy)phosphazene (18); poly(2-methoxyethoxyethoxythionyl-4,4-methoxyethoxyethoxy-6,6-methoxyethoxyethoxy)phosphazene (19); or (poly(methoxyethoxyethoxy)oxothiazene (20); poly[(2-(2-(2-methoxyethoxy)ethoxy)-ethoxy)propyl alkyl siloxane] (21); poly[methyl(2-(2-(2-methoxyethoxy)ethoxy)-ethoxy)propyl alkyl siloxane] (22); poly[ethyl(2-(2-(2-methoxyethoxy)ethoxy)-ethoxy)propyl alkyl siloxane] (23); poly[propyl(2-(2-(2-methoxyethoxy)ethoxy)-ethoxy)propyl alkyl siloxane] (24); poly[phenyl(2-(2-(2-methoxyethoxy)ethoxy)-ethoxy)propyl alkyl siloxane] (25); or poly[methyl(2-(2-(2-methoxyethoxy)ethoxy)-ethoxy)-ethoxy)-ethoxy)-ethoxy)-ethoxy)-ethoxy)propyl alkyl siloxane] (26); a carrier wherein the inorganic conductive polymer possesses an M
w
weight average molecular weight of from about 5,000 to about 1,000,000, and of an M
n
number average molecular weight of from about 12,000 to about 1,000,000; a carrier wherein the inorganic polymer coating weight thereof is from about 0.1 to about 20 weight percent, or wherein the organic and/or organometallic polymer coating weight is from about 1 to about 3 weight percent; a carrier wherein the organic and/or organometallic polymer possesses a glass transition temperature Tg of from about 120° C. to about 200° C., or wherein the organic and/or organometallic polymer Tg is from about 60° C. to about 80° C.; and the like. Also, in embodiments there are provided carriers wherein the polymers selected can be conductive and thus there is avoided the need to add to the polymer a conductive component such as carbon black. The carrier may in embodiments of the present invention include a polymer coating blend of an organic and an inorganic polymer thereover in admixture with other suitable polymers, and more specifically, with a further polymer, such as a fluoropolymer, polymethylmethacrylate, poly(urethane), especially a crosslinked polyurethane, such as a poly(urethane)polyester and the like, and moreover, the copolymer coating may contain a conductive component, such as carbon black, and which conductive component may be dispersed in the polymer coating. With the conductive component, there can be enabled carriers with increased developer triboelectric response at relative humidities of from about 20 to about 90 percent, improved image quality performance, excellent high conductivity ranges of from about 10
−10
to about 10
−7
(ohm-cm)
−1
, and the like.
Advantages associated with the carriers of the present invention, especially with the polymer blend coating thereover, include a high triboelectrical charge, for example a carrier tribo of from about a plus (positive charge) or negative charge of about 10 to about 70, and more specifically, from about 15 to about 50 microcoulombs per gram, and yet more specifically, from about 15 to about 40 microcoulombs per gram and which carriers possess a conductivity of, for example, from about 10
−6
to about 10
−13
, and more specifically, from about 10
−8
to about 10
−11
and which conductivity is measured by a magnetic brush conducting cell; a reduction in the threshold for the onset of electrical conductivity; tunable conductivity levels, substantially constant carrier conductivity values; excellent adhesion of the coating blend to the carrier core; substantially no affect on the triboelectric properties of the coating polymer like polymethylmethacrylate when this polymer is contained in the blend; high robust carrier tribo charge of a positive value, high toner tribo charge of a negative value, excellent admix, for example from about 1 to about 30 seconds as determined in the charge spectrograph, increased resistance of the carrier and a decreased sensitivity of the carrier triboelectric value to the relative humidity of the environment. The tribo can be determined by a number of known methods, such as the use of a Faraday Cage. With respect to high toner tribo charge of a negative value, this property is of value to xerographic, especially color xerographic applications, primarily because there is enabled development of toner particles into regions of the imaging member, such as a photoreceptor where strong fringe electrical fields exist, that is, at the borders of solids areas and lines. Developing toner particles through these fringe fields minimizes or can eliminate the untoned part of the image which appears between two adjacent colors in an image.
The carrier particles of the present invention can be selected for a number of different imaging systems and devices, such as copiers and printers, inclusive of high speed color xerographic systems, printers, digital systems, multitask imaging and printing, and wherein colored images with excellent and substantially no background deposits are achievable. Developer compositions comprised of the carrier particles illustrated herein and prepared, for example, by a dry coating process are generally useful in electrostatographic or electrophotographic imaging systems, especially xerographic imaging and printing processes, and digital processes. Additionally, the invention developer compositions comprised of substantially conductive carrier particles are useful in imaging methods wherein relatively constant conductivity parameters are desired. Furthermore, in the aforementioned imaging processes the triboelectric charge on the carrier particles can be preselected, which charge is dependent, for example, on the polymer composition and dispersant component applied to the carrier core, and optionally the type and amount of the conductive component selected.
PRIOR ART
The electrostatographic process, and particularly the xerographic process, is well known. This process involves the formation of an electrostatic latent image on a photorec

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