Fluorescent treated external surface additives for toner

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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Reexamination Certificate

active

06291121

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to external surface additives for toners that have been treated with a fluorescent material. More in particular, the invention relates to a quality control method for identifying the presence and amount of an external surface additive of a toner through treatment of the target additive with a fluorescent dye.
2. Description of Related Art
Toners for use in modern xerographic printing machines are required to have specific properties, for example conductivity and triboelectric charging properties. The properties of a toner are set through the selection of materials and amounts of the materials of the toner. To ensure that the toner being produced will possess the requisite properties, it is thus necessary to carefully control the amounts of the materials used in making the toner.
Toners typically comprise at least a binder resin, a colorant and external surface additives. The external surface additives are generally added in small amounts. Examples of surface additives include, for example, silica, titanium dioxide, zinc stearate, etc. Prior to the present invention, various conventional analytical techniques were used to detect the presence and amounts of the various additives. For example, for detecting silica as an external additive, techniques such as X-ray Fluorescence and Inductively Coupled Plasma Spectroscopy have been used. Both of these methods utilize the characteristic light or x-ray energy emission of silicon (Si) at specific wavelengths to quantify the silica (SiO
2
). After measuring the silicon (Si) concentration, the silica (SiO
2
) level is then calculated. However, in a case where two different additives of the same type, for example two different silica additives, are present in the toner, these conventional techniques are unable to distinguish between the two additives.
What is desired, then, is an improved technique for determining the presence and amount of certain external surface additives in a toner.
SUMMARY OF THE INVENTION
It is thus an object of the present invention to develop an improved method for detecting and measuring the presence and amount of an external surface additive of a toner. It is a still further object of the invention to develop such technique that does not adversely affect the properties of the toner. It is a still further object of the present invention to develop a toner and surface additives therefor which can be readily discerned for quality control purposes.
These and other objects of the present invention are achieved by treating an external surface additive of a toner with an amount of a fluorescent material, thereby enabling detection and quantification of the treated external additive with ultraviolet light. The invention thus also includes a toner having an external surface additive that has been treated with a fluorescent material.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
This invention is applicable to the treatment of any external surface additives of any toner composition. The toners may be used in forming known developer compositions, for example one-component and two-component (with carrier particles) developer compositions, without restriction. The toners can be used in developing images in any type of xerographic printing apparatus, for example such as a single component developer unit, magnetic brush developer unit, hybrid jumping developer unit, or hybrid scavengeless developer unit.
Four different color toners, cyan (C), magenta (M), yellow (Y) and black (K), are typically used in developing full color images (although other color toners may also be used). These and other color toners may be prepared in the present invention, without restriction. Each color toner is preferably comprised of at least a resin binder, appropriate colorants, optional internal additives and an external additive package comprised of one or more external surface additives. Suitable and preferred materials for use in preparing toners of the invention will now be discussed.
Illustrative examples of suitable toner resins selected for the toner compositions include vinyl polymers such as styrene polymers, acrylonitrile polymers, vinyl ether polymers, acrylate and methacrylate polymers; epoxy polymers; diolefins; polyurethanes; polyamides and polyimides; polyesters such as the polymeric esterification products of a dicarboxylic acid and a diol comprising a diphenol, crosslinked polyesters; and the like. The polymer resins include homopolymers or copolymers of two or more monomers. Polyester resins are typically a most preferred binder resin. Furthermore, the above-mentioned polymer resins may also be crosslinked.
Illustrative vinyl monomer units in the vinyl polymers include styrene, substituted styrenes such as methyl styrene, chlorostyrene, styrene acrylates and styrene methacrylates; vinyl esters like the esters of monocarboxylic acids including methyl acrylate, ethyl acrylate, n-butyl-acrylate, isobutyl acrylate, propyl acrylate, pentyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methylalphachloracrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate, and pentyl methacrylate; styrene butadienes; vinyl chloride; acrylonitnle; acrylamide; alkyl vinyl ether and the like. Further exampleg include p-chlorostyrene vinyl naphthalene, unsaturated mono-olefins such as ethylene, propylene, butylene and isobutylene; vinyl halides such as vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate; acrylonitrile, methacrylonitrile, acrylamide, vinyl ethers, inclusive of vinyl methyl ether, vinyl isobutyl ether, and vinyl ethyl ether; vinyl ketones inclusive of vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; vinylidene halides such as vinylidene chloride and vinylidene chlorofluoride; N-vinyl indole, N-vinyl pyrrolidone; and the like.


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