Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Reexamination Certificate
2000-08-22
2001-03-20
Martin, Roland (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
C399S252000
Reexamination Certificate
active
06203960
ABSTRACT:
CROSS REFERENCE TO COPENDING APPLICATIONS AND RELATED PATENTS
Attention is directed to commonly owned and assigned U.S. Pat. No. 6,004,714, issued Dec. 21, 1999, to Ciccarelli, et al., entitled “Toner Compositions.”
Attention is directed to commonly assigned copending applications: U.S. Ser. No. 09/132,623 filed Aug. 11, 1998, entitled “Toner Compositions”, discloses a toner comprised of resin, colorant and a coated silica, and wherein the silica has a primary particle size of about 25 nanometers to about 55 nanometers and an aggregate size of about 225 nanometers to about 400 nanometers and a coating comprised of a mixture of an alkylsilane, and an aminoalkylsilane; and U.S. Ser. No. 09/132,185 filed Aug. 11, 1998, entitled “Toner Compositions”, discloses a toner with a coated silica with, for example, certain BET characteristics. The disclosures of each the above mentioned patent(s) are incorporated herein by reference in their entirety. The appropriate components and processes of these patents may be selected for the toners and processes of the present invention in embodiments thereof.
The disclosures of each the above mentioned references are incorporated herein by reference in their entirety. The appropriate components and processes of these references may be selected for the toners and processes of the present invention in embodiments thereof.
BACKGROUND OF THE INVENTION
This invention relates generally to improved toner compositions. More specifically the present invention relates to toner compositions including an externally situated performance additive or additives comprised of one or more specifically surface treated fumed silica particulate materials. Fumed silicas are known ultrafine silicon dioxide particulate materials that can have a variety of surface coatings thereover, and which particles and the selection of the coatings thereover can have a profound influence upon the toner and developer properties and performance characteristics. The present invention provides improved examples of surface treated fumed silica particulate materials and which materials can be readily be prepared and provide superior and unexpected toner charging properties, improved imaging processes and imaging apparatuses, and extended life-time of various imaging apparatus components, such as fuser rollers, and the like componentry utilizing the improved toner. The imaging processes of the present invention provide toners with high flow properties and stable A
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properties that prevent or eliminate background deposits on the developed images, and effectively eliminate or minimize the detrimental so-called toner “charge through” phenomena. The imaging processes of the present invention provide working toners with an unimodal charge distribution, that is toners with little or no low charge or wrong sign toner as measured by a charge spectrograph. The imaging processes of the present invention provide toners that when fresh toner is dispensed into aged toner in a machine-throughput mode, little or no low charge or wrong sign toner is formed or remains in the working toner as measured by a charge spectrograph. The toner compositions of the present invention in embodiments thereof possess excellent admix characteristics, maintain their triboelectric charging characteristics for an extended number of imaging cycles, and enable the elimination or minimization of undesirable background deposits or spots on the imaging member or photoconductor, and the image receiver sheet or copy paper. Furthermore, the toner compositions of the present invention are substantially insensitive to relative humidity in a printing or copying machine environment and permit developed images with excellent optical densities and low background. Developers of the present invention are comprised of the toners and carrier particles, especially carrier particles comprised of a core with a mixture of polymers thereover. The toner and developer compositions of the present invention can be selected for electrophotographic imaging and printing processes, especially color processes and particularly digital processes.
The toner and developer compositions of the present invention can be selected for electrophotographic, especially xerographic, imaging and printing processes, including color, digital processes, and multicomponent systems apparatus and machines.
PRIOR ART
In U.S. Pat. No. 5,914,210, to Demizu et al., issued Jun. 22, 1999, there is disclosed a reversal development of an electrostatic latent image formed on a positively charged amorphous silicon type photoreceptor, with a developer including positively charged toner particles containing binder resin and a colorant, first inorganic fine particles having a number-average particle diameter of 0.1 to 3 microns, and second inorganic fine particles subjected to surface treatment by a hydrophobic agent and having an average primary particle diameter of 0.005 to 0.02 microns.
In U.S. Pat. No. 4,973,540, to Machida, et al., issued Nov. 27, 1990, there is disclosed a developer for developing electrostatic latent images formed on an electrostatic latent image carrier, which comprises a toner including: a resin, a colorant, and an inorganic fine particle with at least both a negatively chargeable polar group and a positively chargeable polar group on the surface of the inorganic fine particle.
In U.S. Pat. No. 4,845,004, to Kobayashi, issued Jul. 4, 1989, there is disclosed a hydrophobic silica-type micropowder comprising silica-type microparticles which have been treated with certain secondary or tertiary amine-functional silanes. When the micropowder is combined with a positively-charging resin powder, such as a toner, the fluidity of the resin powder is substantially increased and this improved fluidity is retained upon long term storage.
In U.S. Pat. No. 6,004,714, to Ciccarelli, et al., issued Dec. 21, 1999, there is disclosed a toner comprised of binder, colorant, and a silica containing a coating of an alkylsilane.
In U.S. Pat. No. 3,900,588, issued Aug. 19, 1975, to Fisher et al., there is disclosed an imaging technique and composition for developing electrostatographic latent images whereby a developer composition is employed comprising toner, a substantially smearless polymeric additive like KYNAR®, and an abrasive material surface additive such as silica, like AEROSIL R972®, or strontium titanate, see column 7, lines 12 to 17.
In U.S. Pat. No. 5,437,955, issued Aug. 1, 1995, to Michlin, there is disclosed a dry toner composition for electrophotography including a binder resin, a coloring agent and a mica-group mineral, which mineral provides the toner composition with lubricity and better flow capabilities. The mica-group mineral is wet ground and may be coated with calcium stearate to reduce static electricity generated during operation of the electrophotographic machine.
In U.S. Pat. No. 4,395,485, issued Jul. 26,1983, to Kashiwage, et al., there is disclosed a one component type dry developer for electrophotography which is improved on humidification, and consists of a mixture of toner with a particle size of about 5 to 50 microns and a hydrophobic flow agent. The flow agent is made by coating inorganic, organic, metallic or an alloy powder with a thin film of non-hydrophilic synthetic resin. A flow agent having non-hydrophilic and electrically conductive properties is obtained.
The aforementioned patents are incorporated in their entirety by reference herein.
Other patents of interest follow. Toners and developers with surface additives of metal salts of fatty acids like zinc stearate and silica are known, reference for example U.S. Pat. Nos. 3,983,045 and 3,590,000. The commonly owned and assigned U.S. Pat. No. 3,983,045, issued Sep. 28, 1976, to Jugle et al., discloses a developer composition comprising 1) electroscopic toner particles, 2) a friction-reducing material, such as fatty acids, metal salts of fatty acids, fatty alcohols, fluorocarbon compounds, polyethylene glycols, and the like, of a hardness less than the toner and having greater friction-reducing
Bayley Denise R.
Ciccarelli Roger N.
Pickering Thomas R.
Haack John L.
Martin Roland
Xerox Corporation
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