Toner compositions with hydroxy naphthoic acid charge enhancing additives

Disclosed is a negatively charged toner composition comprised of resin particles, pigment particles, optional surface additives, and a hydroxy naphthoic acid charge enhancing additive of the following formula: ##STR1## wherein X is halogen, hydroxy, or hydrogen, M is hydrogen, an alkaline earth, an alkali metal, or NR.sub.4 wherein R is alkyl with from 1 to 5 carbon atoms, and n is the number 1 or 2.

BACKGROUND OF THE INVENTION 
The invention is generally directed to toner and developer compositions, 
and more specifically, the present invention is directed to developer and 
toner compositions containing charge enhancing additives, which impart or 
assist in imparting a negative charge to the toner particles and enable 
toners with rapid triboelectric charging characteristics. In one 
embodiment, there are provided in accordance with the present invention 
toner compositions comprised of resin particles, pigment particles and 
certain charge enhancing additives. In embodiments, the present invention 
is directed to toners with hydroxy naphthoic acid derivative charge 
enhancing additives. The aforementioned charge additives in embodiments of 
the present invention enable, for example, toners with high, that is from 
about -10 to about -50 microcoulombs per gram as determined by known 
methods like the Faraday Cage, triboelectric properties, rapid 
triboelectric charging characteristics, extended developer life, 
triboelectrical properties which change systematically with environmental 
conditions, for example, the toner triboelectric charging is from about 
-15 to about -30 microcoulombs/gram at a relative humidity of 20 percent, 
and from about -30 to about -50 microcoulombs/gram at a relative humidity 
of 80 percent, and high image print quality with substantially no 
background deposits. Also, the aforementioned toner compositions usually 
contain a colorant component comprised of, for example, carbon black, 
magnetites, or mixtures thereof, color pigments or dyes with cyan, 
magenta, yellow, blue, green, red, or brown color, or mixtures thereof 
thereby providing for the development and generation of black and/or 
colored images. The toner and developer compositions of the present 
invention can be selected for electrophotographic, especially xerographic, 
imaging and printing processes, including color processes. 
Toners with negative charge additives are known, reference for example U.S. 
Pat. Nos. 4,411,974 and 4,206,064, the disclosures of which are totally 
incorporated herein by reference. The '974 patent discloses negatively 
charged toner compositions comprised of resins, pigment particles, and as 
a charge enhancing additive ortho-halophenyl carboxylic acids. Similarly, 
there are disclosed in the '064 patent toner compositions with chromium, 
cobalt, and nickel complexes of salicylic acid as negative charge 
enhancing additives. In U.S. Pat. No. 4,845,003, there are illustrated 
negatively charged toners with certain aluminum salt charge additives. 
More specifically, this patent discloses as charge additives aluminum 
complexes comprised of two or three hydroxybenzoic acid ligands bonded to 
a central aluminum ion. While these charge additives may have the 
capability of imparting negative triboelectric charge to toner particles, 
they are generally not efficient in promoting the rate of triboelectric 
charging of toner particles. A fast rate of triboelectric charging is 
particularly crucial for high speed xerographic machines since, for 
example, these machines consume toner rapidly, and fresh toner has to be 
constantly added. The added uncharged toners, therefore, must charge up to 
their equilibrium triboelectric charge level rapidly to ensure no 
interruption in the xerographic imaging or printing operation. Another 
disadvantage with these charge additives is their thermal instability, 
that is they often break down during the thermal extrusion process of the 
toner manufacturing cycle. Most or many of these and other disadvantages 
are eliminated, or substantially eliminated with the toners containing the 
charge additives of the present invention. Toners with various charge 
additive including aluminum complexes are disclosed, for example, in U.S. 
Pat. Nos. 4,404,271; 4,656,112; 4,762,763; 4,845,003; 4,767,688; 4,378,420 
and 4,433,040. 
Developer compositions with charge enhancing additives, which impart a 
positive charge to the toner particles, are also well known. Thus, for 
example, there is described in U.S. Pat. No. 3,893,935 the use of 
quaternary ammonium salts as charge control agents for electrostatic toner 
compositions; U.S. Pat. No. 4,221,856 discloses electrophotographic toners 
containing resin compatible quaternary ammonium compounds in which at 
least two R radicals are hydrocarbons having from 8 to about 22 carbon 
atoms, and each other R is a hydrogen or hydrocarbon radical with from 1 
to about 8 carbon atoms, and A is an anion, for example sulfate, 
sulfonate, nitrate, borate, chlorate, and the halogens such as iodide, 
chloride and bromide, reference the Abstract of the Disclosure and column 
3; a similar teaching is presented in U.S. Pat. No. 4,312,933 which is a 
division of U.S. Pat. No. 4,291,111; similar teachings are presented in 
U.S. Pat. No. 4,291,112 wherein A is an anion including, for example, 
sulfate, sulfonate, nitrate, borate, chlorate, and the halogens; U.S. Pat. 
No. 4,338,390, the disclosure of which is totally incorporated herein by 
reference, discloses developer compositions containing as charge enhancing 
additives organic sulfate and sulfonates, which additives can impart a 
positive charge to the toner composition; and U.S. Pat. No. 4,298,672, the 
disclosure of which is totally incorporated herein by reference, discloses 
positively charged toner compositions with resins and pigment particles, 
and as charge enhancing additives alkyl pyridinium compounds. 
Negatively charged toners are illustrated in U.S. Pat. No. 5,250,379, 
issued Oct. 5, 1993, to Bayley et al., which illustrates a negatively 
charged toner composition comprised of resin, pigment, and an aluminum 
charge enhancing additive of the following formula 
##STR2## 
Illustrated in U.S. Pat. No. 5,275,900, issued Jan. 4, 1994, to Ong et al., 
are toner compositions comprised of polymer resins, colorants comprised of 
color pigment particles or dye molecules, and certain metal complex charge 
additives derived from the reaction of a mixture of a hydroxybenzoic acid 
and a base with a metal ion in the presence of an excess of a 
hydroxyphenol. More specifically, this copending application illustrates a 
negatively charged toner composition comprised of polymer, colorant, 
optional surface additives, and a metal complex charge enhancing additive 
of the following formula 
##STR3## 
where M is a metal; N.sup.+ is a cation; R and R' are alkyl, alkoxy, 
aryloxy, halogen, carbonyl, amino, nitro, or mixtures thereof; m and n are 
the number of R substituents ranging from 0 to 3; y.sup.- is the magnitude 
of the negative charge of the anion; and y' represents the number of 
cations. 
Illustrated in U.S. Pat. No. 5,300,387, issued Apr. 4, 1994, to Ong, is a 
negatively charged toner composition comprised of a polymer or polymers, 
pigment, and a metal complex charge enhancing additive as essentially 
represented by the following formula 
##STR4## 
where M is the central metal ion; N.sup.+ is the counter cation; R and R' 
are selected from the group consisting of alkyl, alkoxy, aryloxy, halogen, 
carbonyl group, alkoxycarbonyl group, amino group, nitro group or mixtures 
thereof; m and n are the number of R substituents on the aromatic rings, 
ranging from 0 to 3; y.sup.- is the magnitude of the negative charge of 
the anion or the number of the counter cations of the metal complex, and 
represents the number 1 or 2; and y' represents the number of 
countercations N.sup.+. 
Illustrated in copending application U.S. Ser. No. 964,544 is a toner 
composition comprised of a polymer or polymers, pigment particles and/or 
dyes, optional surface additives, and a charge enhancing additive of the 
following formula 
##STR5## 
wherein R is hydrogen, alkyl, or aryl, R' and R" are selected from the 
group consisting of alkyl, alkoxy, aryl, and aryloxy, R'" is selected from 
the group consisting of alkyl, alkoxy, oxide, and halide, M is boron or a 
metal, x is a number of from 1 to 4, and y is a number of from 0 to 2. 
Illustrated in U.S. Pat. No. 5,290,651, issued Mar. 1, 1994, to Ong, is a 
negatively charged toner composition comprised of polymer, pigment, 
optional surface additives, and a zinc complex charge enhancing additive 
represented by either of the two following formulas: 
##STR6## 
wherein R, R', R", and R'" are independently selected from the group 
consisting of hydrogen, alkyl, aryl alkoxy, aryloxy, halogen, amino, and 
hydroxy. 
Illustrated in U.S. Pat. Nos. 5,256,514 and 5,256,515, issued Oct. 26, 1993 
to Law et al., are negatively charged toner compositions comprised of 
resin particles, pigment particles, optional surface additives and 
halogenated salicyclic acid and metal complex derivative charge enhancing 
additives of the following formulas, respectively as defined therein. 
##STR7## 
The disclosures of each of the aforementioned copending applications and 
U.S. Patents are totally incorporated herein by reference. 
Although many charge enhancing additives are known, there continues to be a 
need for charge enhancing additives which when incorporated in toners, 
render the toners with many of the advantages illustrated herein. There is 
also a need for negative charge enhancing additives which are useful for 
incorporation into black and colored toner compositions which can be 
utilized for developing positive electrostatic latent images. Moreover, 
there is a need for colored toner compositions containing charge enhancing 
additives which do not interfere with the color quality of the colorants 
present in the toners. There is also a need for toner compositions 
containing charge additives which do not contain transition metals or 
heavy metals as a constituent of the charge additive component. Another 
need relates to the provision of toner compositions with certain charge 
enhancing additives, which toners in embodiments thereof possess 
substantially stable triboelectric charge levels, and display acceptable 
rates of triboelectric charging characteristics. Furthermore, there is 
also a need for toner compositions with certain charge enhancing additives 
which possess excellent dispersibility characteristics in toner resins, 
and can, therefore, form stable dispersions in the toner compositions. 
There is also a need for negatively charged black and colored toner 
compositions that are useful for incorporation into various imaging 
processes, inclusive of color xerography, as illustrated in U.S. Pat. No. 
4,078,929, the disclosure of which is totally incorporated herein by 
reference; laser printers; and additionally a need for toner compositions 
useful in imaging apparatuses having incorporated therein layered 
photoresponsive imaging members, such as the members illustrated in U.S. 
Pat. No. 4,265,990, the disclosure of which is totally incorporated herein 
by reference. Also, there is a need for negative toner compositions which 
have desirable triboelectric charge levels of, for example, from between 
about -10 to about -50 microcoulombs per gram, and preferably from about 
-15 to about -45 microcoulombs per gram, and triboelectric charging rates 
of less about 120 seconds, and preferably from about 15 to about 60 
seconds as measured by standard charge spectrograph methods when the 
toners are frictionally charged against suitable carrier particles via 
conventional roll milling techniques. There is also a need for metal free, 
nontoxic, substantially nontoxic, or environmentally compatible charge 
enhancing additives which when incorporated at effective concentrations 
of, for example, less than 7 weight percent, preferably less than 4 weight 
percent in toners, render the toners to be xerographically and 
environmentally efficacious. The concentrations of the charge additives 
that can be incorporated into the toner compositions generally range from 
about 0.05 weight percent to about 5 weight percent, depending on whether 
the charge additive is utilized as a surface additive or as a dispersion 
in the bulk of the toner. The effective concentrations of toner in the 
developer, that is toner and carrier particles, are, for example, from 
about 0.5 to about 5 weight percent, preferably from about 1 to about 3 
weight percent. There is also a need for charge additives that can charge 
toners with small particle diameters of, for example, less than about 7 
microns, and more specifically from about 2 to 7 microns in average volume 
diameter. Another need relates to toner and developer tribocharging 
characteristics which are insensitive to RH or where the tribo does not 
decrease at high RH, and alternatively, to tribo characteristics which 
vary systematically with ambient relative humidity, in particular, a 
triboelectric charging characteristic which becomes more negative from 
about -15 to about -45 microcoulombs per gram as the relative humidity 
increases over the range of about 20 to about 80 percent. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide toner and developer 
compositions with negative charge enhancing additives. 
It is an object of the present invention to provide economically negatively 
charged toner compositions useful for the development of electrostatic 
latent images including color images. 
In yet a further object of the present invention there are provided, it is 
believed, humidity insensitive triboelectrically stable developer 
compositions and humidity advantageous developer compositions wherein the 
triboelectric charge levels improve, that is, become more negative, with 
increasing relative humidity, from about, for example, 20 to 85 percent 
relative humidity at temperatures of from 60 to 80.degree. F. as 
determined in a relative humidity testing chamber, negatively charged 
toner compositions with desirable triboelectric charging rates of less 
than 120 seconds, and preferably less than 60 seconds as determined by the 
charge spectrograph method, and acceptable triboelectric charging levels 
of from about -10 to about -50 microcoulombs per gram. 
Another object of the present invention resides in the preparation of 
negative toners which will enable the development of images in 
electrophotographic imaging apparatuses, which images have substantially 
no background deposits thereon, are substantially smudge proof or smudge 
resistant, and therefore, are of excellent resolution; and further, such 
toner compositions can be selected for high speed electrophotographic 
apparatuses, that is for example those exceeding 50 copies per minute. 
These and other objects of the present invention may be accomplished in 
embodiments thereof by providing toner compositions comprised of polymer 
resins, colorants comprised of color pigment particles or dye molecules, 
and certain charge additives. More specifically, the present invention in 
embodiments is directed to a negatively charged toner composition 
comprised of resin particles, pigment particles, optional surface 
additives, and a hydroxy naphthoic acid charge enhancing additive of the 
following formula: 
##STR8## 
wherein X is halogen such as bromide or iodide, hydroxy, or hydrogen, M is 
hydrogen, an alkaline earth such as magnesium calcium, barium, and the 
like metal, an alkali metal such as lithium, sodium, potassium, and the 
like, or NR.sub.4 wherein R is alkyl, and n is the number 1 or 2. 
Examples of alkyl include known substituents such as those with 1 to about 
25 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, 
octyl, nonyl, and the like. 
Examples of specific charge additives of the present invention include, but 
are not limited to 1,6-dibromo-2-hydroxy-3-naphthoic acid, lithium 
1,6-dibromo-2-hydroxy-3-naphthoate, 2-hydroxy-6-bromo-3-naphhthoic acid, 
lithium 2-hydroxy-6-bromo-3-naphthoate, sodium 
2-hydroxy-6-bromo-3-naphthoate, 1,6-diiodo-2-hydroxy-3-naphthoic acid, and 
2-hydroxy-3-naphthoic acid. 
The aforementioned charge additives can be incorporated into the toner, may 
be present on the toner surface, or may be present on toner surface 
additives such as colloidal silica particles The charge additives are 
present in the toner composition in effective amounts of from about 0.01 
to about 5 weight percent and preferably from about 0.1 to about 3 weight 
percent based on the total weight of the toner composition. Advantages of 
rapid triboelectric charging characteristics of generally less than 120 
seconds, and preferably less than 60 seconds in embodiments as measured by 
the standard charge spectrograph methods when the toners are frictionally 
charged against carrier particles by known conventional roll mixing 
methods, appropriate triboelectric charge levels, and the like can be 
achieved with many of the aforementioned toners of the present invention. 
In embodiments, when the aforementioned charge additives are included in 
the toner composition in the manner specified above, the rate of 
tribocharging of the resultant toner is from about 15 seconds to about 120 
seconds as measured by frictional charging methods against suitable 
carrier particles. In another embodiment of the present invention, there 
are provided, subsequent to known micronization and classification, toner 
particles with a volume average diameter of from about 4 to about 20 
microns. 
The hydroxy naphthoic acid, used as a starting material for the preparation 
of the hydroxy naphthoic derivative charge additives of the present 
invention, is commercially available from, for example, Aldrich Chemical 
Company. The alkali and alkaline salts of hydroxy naphthoic acid and 
halogenated derivatives thereof can be prepared by, for example, adding 
thereto an equivalent molar amount of a metal hydroxide to an alcoholic, 
such as methanolic solution of the hydroxynaphthoic acid, followed by 
removal of the alcoholic solvent. The halogenated hydroxy naphthoic acid 
derivatives can be prepared using known halogenation procedures, for 
example, treating a solution of hydroxy naphthoic acid in acetic acid with 
molecular bromine. 
A number of equally useful halogenating agents are known that afford 
halogenated reaction products at selected sites in aromatic compounds, for 
example, as disclosed by House in "Modern Synthetic Reactions", W. A. 
Benjamin, Inc., 2nd Ed., Chapter 8, page 422, and references cited 
therein, the disclosure of which is incorporated in its entirety by 
reference. 
From the foregoing, it is readily evident to one of ordinary skill in the 
art that a variety of halogen substituted hydroxy naphthoic acid compounds 
and metal salt derivatives thereof may be prepared. 
The toner compositions of the present invention can be prepared by a number 
of known methods such as admixing and heating polymer resins such as 
styrene butadiene copolymers, polyesters, such as S II.RTM., styrene 
acrylates, or styrene methacrylates, colorants such as color pigment 
particles or dye compounds, and the aforementioned charge enhancing 
additive, or mixtures of charge additives in a concentration preferably 
ranging from about 0.5 percent to about 5 percent in a toner extrusion 
device, such as the ZSK53 available from Werner Pfleiderer, and removing 
the resulting toner composition from the device. Subsequent to cooling, 
the toner composition is subjected to grinding utilizing, for example, a 
Sturtevant micronizer for the purpose of achieving toner particles with a 
volume average diameter of from about 4 to about 25 microns, and 
preferably from about 4 to about 12 microns, which diameters are 
determined by a Coulter Counter. Subsequently, the toner compositions can 
be classified utilizing, for example, a Donaldson Model B classifier for 
the purpose of removing unwanted fine toner particles. 
Illustrative examples of suitable toner resins selected for the toner and 
developer compositions of the present invention include vinyl polymers 
such as styrene polymers, acrylonitrile polymers, vinyl ether polymers, 
acrylate and methacrylate polymers; epoxy polymers; polyurethanes; 
polyamides and polyimides; polyesters like S II.RTM. available from 
Hercules Chemical Company; and the like. The polymer resins selected for 
the toner compositions of the present invention include homopolymers or 
copolymers of two or more monomers. Furthermore, the above mentioned 
polymer resins may also be crosslinked depending on the desired toner 
properties. Illustrative vinyl monomer units selected for the vinyl 
polymers include styrene, substituted styrenes such as methyl styrene, 
chlorostyrene, methyl acrylate and methacrylate, ethyl acrylate and 
methacrylate, propyl acrylate and methacrylate, butyl acrylate and 
methacrylate, pentyl acrylate and methacrylate, butadiene, vinyl chloride, 
acrylonitrile, acrylamide, alkyl vinyl ether and the like. Illustrative 
examples of the dicarboxylic acid units in the polyester resins suitable 
for use in the toner compositions of the present invention include 
phthalic acid, terephthalic acid, isophthalic acid, succinic acid, 
glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, 
sebacic acid, maleic acid, fumaric acid, dimethyl glutaric acid, 
bromoadipic acids, dichloroglutaric acids, and the like; while 
illustrative examples of the diol segments in the polyester resins include 
ethanediol, propanediols, butanediols, pentanediols, pinacol, 
cyclopentanediols, hydrobenzoin, bis(hydroxyphenyl)alkanes, 
dihydroxybiphenyl, substituted dihydroxybiphenyls, and the like. 
As one toner resin, there are selected polyester resins derived from a 
dicarboxylic acid and a diphenol. These resins are illustrated in U.S. 
Pat. No. 3,590,000, the disclosure of which is totally incorporated herein 
by reference, polyester resins obtained from the reaction of bisphenol A 
and propylene oxide, followed by the reaction of the resulting product 
with fumaric acid, and branched polyester resins resulting from the 
reaction of dimethylterephthalate with 1,3-butanediol, 1,2-propanediol, 
and pentanetriol. Further, low melting polyesters, especially those 
prepared by reactive extrusion, reference copending U.S. Ser. No. 814,641, 
and U.S. Pat. No. 5,227,460, issued Jul. 13, 1993, to Mahabadi et al., the 
disclosures of which are totally incorporated herein by reference, can be 
selected as toner resins. Other specific toner resins include 
styrene-methacrylate copolymers and styrene-butadiene copolymers; 
PLIOLITES.RTM.; suspension polymerized styrene-butadienes, reference U.S. 
Pat. No. 4,558,108, the disclosure of which is totally incorporated herein 
by reference. Also, waxes with a molecular weight of from about 1,000 to 
about 6,000, such as polyethylene, polypropylene, and paraffin waxes, can 
be included in or on the toner compositions as fuser roll release agents. 
The toner resin is present in a sufficient, but effective amount, for 
example from about 30 to about 95 weight percent. Thus, when 1 percent by 
weight of the charge enhancing additive is present, and 8 percent by 
weight of colorant, such as carbon black or color pigment, is contained 
therein, about 92 percent by weight of resin is selected. Also, the charge 
enhancing additive of the present invention may be applied as a surface 
coating on the toner particles. When used as a coating, the charge 
enhancing additive of the present invention is present in an amount of 
from about 0.05 weight percent to about 5 weight percent, and preferably 
from about 0.1 weight percent to about 1.0 weight percent. Also, in 
embodiments the charge additive may be admixed with colloidal silica 
particles and adsorbed on the surface thereof, and the resulting product 
is then applied to the toner as a surface additive. 
Numerous well known suitable color pigments or dyes can be selected as the 
colorant for the toner compositions including, for example, carbon black, 
like REGAL.RTM.330, nigrosine dye, metal phthalocyanines, aniline blue, 
magnetite, or mixtures thereof. The colorant, which is preferably carbon 
black or other color pigments, should be present in a sufficient amount to 
render the toner composition with a sufficiently high color intensity. 
Generally, the colorants are present in amounts of from about 1 weight 
percent to about 20 weight percent, and preferably from about 2 to about 
10 weight percent based on the total weight of the toner composition; 
however, lesser or greater amounts of colorant can be selected. 
When the colorants are comprised of magnetites or a mixture of magnetites 
and color pigment particles, thereby enabling single component toners and 
toners for magnetic ink character recognition (MICR) applications in some 
instances, which magnetites are a mixture of iron oxides (FeO.Fe.sub.2 
O.sub.3) including those commercially available as MAPICO BLACK.RTM., they 
are present in the toner composition in an amount of from about 5 weight 
percent to about 70 weight percent, and preferably in an amount of from 
about 10 weight percent to about 50 weight percent. Mixtures of carbon 
black and magnetite with from about 1 to about 15 weight percent of carbon 
black, and preferably from about 2 to about 6 weight percent of carbon 
black, and magnetite, such as MAPICO BLACK.RTM., in an amount of, for 
example, from about 5 to about 70, and preferably from about 10 to about 
50 weight percent can be selected for black toner compositions of the 
present invention. 
There can also be blended with the toner compositions of the present 
invention external additives including flow aid additives, which additives 
are usually present on the surface thereof. Examples of these additives 
include colloidal silicas such as AEROSIL.RTM., metal salts and metal 
salts of fatty acids inclusive of zinc stearate, aluminum oxides, cerium 
oxides, titanium oxides, and mixtures thereof, which additives are 
generally present in an amount of from about 0.1 percent by weight to 
about 5 percent by weight, and preferably in an amount of from about 0:5 
percent by weight to about 2 percent by weight. Several of the 
aforementioned additives are illustrated in U.S. Pat. Nos. 3,590,000 and 
3,800,588, the disclosures of which are totally incorporated herein by 
reference. 
With further respect to the present invention, colloidal silicas such as 
AEROSIL.RTM. can be surface treated by adding the silicas to a solution of 
the charge additive in an amount of from about 1 to about 50 weight 
percent, and preferably 10 weight percent to about 25 weight percent, 
followed by the addition thereof to the toners in an amount of from 0.1 to 
10 and preferably 0.1 to 5 weight percent. 
Also, there can be included in the toner compositions of the present 
invention low molecular weight waxes, such as polypropylenes and 
polyethylenes commercially available from Allied Chemical and Petrolite 
Corporation, EPOLENE N-15.TM. commercially available from Eastman Chemical 
Products, Inc., VISCOL 550-P.TM., a low weight average molecular weight 
polypropylene available from Sanyo Kasei K.K., and similar materials. The 
commercially available polyethylenes selected have a molecular weight of 
from about 1,000 to about 1,500, while the commercially available 
polypropylenes utilized for the toner compositions of the present 
invention are believed to have a molecular weight of from about 4,000 to 
about 5,000. Many of the polyethylene and polypropylene compositions 
useful in the present invention are illustrated in British Patent No. 
1,442,835, the disclosure of which is totally incorporated herein by 
reference. These low molecular weight wax materials are present in the 
toner composition of the present invention in various amounts, however, 
generally these waxes are present in the toner composition in an amount of 
from about 1 percent by weight to about 15 percent by weight, and 
preferably in an amount of from about 2 weight percent to about 10 weight 
percent. 
Encompassed within the scope of the present invention are colored toner and 
developer compositions comprised of toner resins, optional carrier 
particles, the charge enhancing additives illustrated herein, and as 
colorants red, blue, green, brown, magenta, cyan and/or yellow dyes or 
color pigments, as well as mixtures thereof. More specifically, with 
regard to the generation of color images utilizing a developer composition 
with the charge enhancing additives of the present invention, illustrative 
examples of magenta materials that may be selected as colorants include, 
for example, 2,9-dimethyl-substituted quinacridone and anthraquinone dye 
identified in the Color Index as Cl 60710, Cl Dispersed Red 15, diazo dye 
identified in the Color Index as Cl 26050, Cl Solvent Red 19, and the 
like. Illustrative examples of cyan materials that may be used as 
colorants include copper phthalocyanine, listed in the Color Index as Cl 
74160, Cl Pigment Blue, and Anthrathrene Blue, identified in the Color 
Index as Cl 69810, Special Blue X-2137, and the like; while illustrative 
examples of yellow pigments that may be selected are diarylide yellow 
3,3-dichlorobenzidene acetoacetanilides, a monoazo pigment identified in 
the Color Index as Cl 12700, Cl Solvent Yellow 16, a nitrophenyl amine 
sulfonamide identified in the Color Index as Foron Yellow SE/GLN, Cl 
Dispersed Yellow 33, 2,5-dimethoxy-4-sulfonanilide 
phenylazo-4'-chloro-2,5-dimethoxy acetoacetanilide, and Permanent Yellow 
FGL. The aforementioned colorants are incorporated into the toner 
composition in various suitable effective amounts providing the objectives 
of the present invention are achieved. In embodiments, these colorants are 
present in the toner composition in an amount of from about 1 percent by 
weight to about 15 percent by weight based on the total weight of the 
toner. 
For the formulation of developer compositions, there are mixed with the 
toner particles carrier components, particularly those that are capable of 
triboelectrically assuming an opposite polarity to that of the toner 
composition. Accordingly, the carrier particles of the present invention 
are selected to be those that would render the toner particles negatively 
charged while acquiring a positive charge polarity via frictional charging 
against the toner particles of the present invention. The opposite charge 
polarities of the carrier and toner particles of the developer composition 
thus ensure the toner particles to adhere to and surround the carrier 
particles. Illustrative examples of carrier particles include iron powder, 
steel, nickel, iron, ferrites, including copper zinc ferrites, nickel zinc 
ferrites, and the like. Additionally, there can be selected as carrier 
particles nickel berry carriers as illustrated in U.S. Pat. No. 3,847,604, 
the disclosure of which is totally incorporated herein by reference. The 
selected carrier particles can be used with or without a coating, the 
coating generally containing terpolymers of styrene, methylmethacrylate, 
and a silane, such as triethoxysilane, reference U.S. Pat. Nos. 3,526,533 
and 3,467,634, the disclosures of which are totally incorporated herein by 
reference; polymethyl methacrylates; other known coatings; and the like. 
The carrier particles may also include in the coating, which coating can 
be present in one embodiment in an amount of from about 0.1 to about 3 
weight percent, conductive substances such as carbon black in an amount of 
from about 5 to about 30 percent by weight. Polymer coatings not in close 
proximity in the triboelectric series can also be selected, reference U.S. 
Pat. Nos. 4,937,166 and 4,935,326, the disclosures of which are totally 
incorporated herein by reference, including for example KYNAR.RTM. and 
polymethylmethacrylate mixtures (40/60). Coating weights can vary as 
indicated herein; generally, however, from about 0.3 to about 2, and 
preferably from about 0.5 to about 1.5 weight percent coating weight is 
selected. 
Furthermore, the diameter of the carrier particles, preferably spherical in 
shape, is generally from about 50 microns to about 1,000, and preferably 
from between about 60 and 200 microns in volume average diameter thereby 
permitting them, for example, to possess sufficient density and inertia to 
avoid adherence to the electrostatic images during the development 
process. The carrier component can be mixed with the toner composition in 
various suitable combinations, such as about 1 to 5 parts of toner to 
about 100 parts to about 200 parts by weight of carrier. 
The toner composition of the present invention can be prepared by a number 
of known methods including extrusion melt blending the toner resins, 
colorants, and the hydroxy naphthoic acid derivative charge enhancing 
additive of the present invention as indicated herein, followed by 
mechanical attrition and classification. Other methods include those well 
known in the art such as spray drying, melt dispersion, extrusion 
processing, dispersion polymerization, and suspension polymerization. 
Also, as indicated herein the toner composition without the charge 
enhancing additive can be first prepared, followed by addition of the 
charge enhancing additive and other optional surface additives, or the 
charge enhancing additive-treated surface additive such as colloidal 
silicas. Further, other methods of preparation for the toner are as 
illustrated herein. 
The toner and developer compositions of the present invention may be 
selected for use in electrostatographic imaging and printing apparatuses 
containing therein conventional photoreceptors providing that they are 
capable of forming positive electrostatic latent images relative to the 
triboelectric charge polarity of the toners. 
The toners of the present invention are usually jetted and classified 
subsequent to preparation to enable toner particles with a preferred 
volume average diameter of from about 4 to about 25 microns, and more 
preferably from about 5 to about 12 microns. The triboelectric charging 
rates for the toners of the present invention are in embodiments less than 
120 seconds, and more specifically, from about 15 to about 60 seconds as 
determined by the known charge spectrograph method as described herein 
before. These toner compositions with rapid rates of triboelectric 
charging characteristics enable, for example, the development of images in 
electrophotographic imaging apparatuses, which images have substantially 
no background deposits thereon, even at high toner dispensing rates in 
some instances, for instance exceeding 30 grams per minute; and further, 
such toner compositions can be selected for high speed electrophotographic 
apparatuses, that is those exceeding 50 copies per minute. 
The following Examples are being supplied to further illustrate various 
embodiments of the present invention, it being noted that these Examples 
are intended to illustrate and not limit the scope of the present 
invention. Comparative Examples are also presented.

EXAMPLE I 
Preparation of 1,6-dibromo-2-hydroxy-3-naphthoic acid 
2-Hydroxy-3-naphthoic acid (188.2 g, 1 mole) was heated to 90.degree. C. in 
a 3 L flask containing 1,700 mL of glacial acetic acid until dissolved 
(about 20-30 minutes). A bromine solution consisting of 352 g of bromine 
and 100 mL of acetic acid was slowly added and evenly over 90 minutes to 
the 2-hydroxy-3-naphthoic acid solution, which was maintained at 
90.degree. C. After the addition was completed, the mixture was stirred 
and brought to reflux for 3 hours. The product mixture was then allowed to 
cool to room temperature slowly (over about 16 hours). A resulting 
precipitated solid was isolated by filtration and rinsed with 300 mL of 
acetic acid. The isolated solid was then suspended in 4 L of water and was 
stirred for 0.5 hour. The purified solid was filtered and washed with 
water 6.times.500 mL. After vacuum drying at 70.degree. C., 290 g of pure 
1,6 -dibromo-2-hydroxy-3-naphthoic acid (84% yield) was obtained with the 
following properties. 
m.p.: 254.degree. C. (dec.) IR (KBr): 1674 cm.sup.-1 (carboxylic acid) 
Calc'd for C.sub.11 H.sub.6 O.sub.3 Br: C, 38.19; H, 1.75; Br, 46.19. 
Found: C, 37.99; H, 1.77; Br, 46.32. 
Application of the charge additive to the surface of AEROSIL and developer 
formulation The isolated charge additive compound, 0.3 gram, was dissolved 
in 100 mL of diethyl ether in a 250 mL round bottom flask. After 
dissolution, 3 grams of AEROSIL.RTM.R972 from Degussa Company was added, 
and the resulting suspension was stirred for 0.5 hour. The ether solvent 
was then removed on a rotary evaporator, and the residue obtained was 
transferred to a crystallization dish where it was dried in a forced air 
oven, about 20 hours at 120.degree. C. The solid was then transferred to a 
4 ounce bottle and roll milled with 35 grams of 1/4 inch steel shot for 30 
minutes at a speed of about 90 feet per minute, yielding 3 grams of a 
fluffy white powder comprised of 10 weight percent of 
1,6-dibromo-2-hydroxy-3-naphthoic acid and 90 weight percent of 
AEROSIL.RTM.R972. The formed white powder charge additive and AEROSIL 
composite, 0.063 gram, was then added together with 12.5 grams of an 
experimental toner, 9 microns in average volume diameter, comprised of 100 
percent of styrene butadiene (89/11), to a 4 ounce bottle containing 125 
grams of steel shot of 1/4 inch diameter and a bottle was then roll milled 
for 30 minutes. 
Developer Preparation 
A developer composition was then prepared by adding 1.25 grams of the above 
prepared toner and 60 grams of a steel core carrier, 130 microns in 
diameter, and 0.7 percent by weight of a surface coating of 
polymethylmethacrylate with 20 weight percent of KYNAR.RTM., to a roll 
mill. Mixing was accomplished for 60 minutes at a speed of about 90 feet 
per minute to generate a time zero developer. The tribo of the resulting 
toner as determined by the known Faraday Cage method at 20 percent RH was 
-65 microcoulombs per gram, and the admix rate was 2 minutes as determined 
in the known charge spectrograph. 
EXAMPLE II 
Sodium 1,6-dibromo-2-hydroxy-3-naphthoate 
There was prepared a negative charge control additive, sodium 
1,6-dibromo-2-hydroxy-3-naphthoate, by neutralizing the acid in Example I 
with an equivalent molar amount of NaOH in methanol. About 0.58 g of NaOH 
in 5 mL of water was added to a 100 mL methanol solution containing 5 g of 
1,6-dibromo-2-hydroxy-3-naphthoic acid. After the mixture was stirred for 
0.5 h, the solvent was removed on the evaporator. The residue was 
recrystallized from a minimum amount of warm water, yielding sodium 
1,6-dibromo-2-hydroxy-3-naphthoate in about 90%. 
m.p.:&gt;300.degree. C. IR(KBr): 1650 cm.sup.-1 (carboxylate) Calc'd for 
C.sub.11 H.sub.5 O.sub.3 Br.sub.2 Na:C, 35.91; H, 1.37; Br 43.43; Na, 6.25 
Found: C, 35.88, H, 1.39; Br, 44.05; Na, 5.69. 
Surface Treatment of Charge Additive on AEROSIL 
The above charge additive, 0.3 gram, as then dissolved in 100 mL of 
methanol in a 250 mL round bottom flask. After dissolution, 3 grams of 
AEROSIL.RTM. R972 from Degussa Company was added, and the resulting 
suspension was stirred for 0.5 hour. The methanol solvent was then removed 
on a rotary evaporator, and the residue obtained was transferred to a 
crystallization dish where it was dried in a forced air oven overnight, 
about 20 hours at 120.degree. C. The solid was then transferred to a 4 
ounce bottle and roll milled with 35 grams of 1/4 inch steel shot for 30 
minutes at a speed of about 90 feet per minute, yielding 3 grams of a 
fluffy white powder comprised of 10 weight percent of sodium 
1,6-dibromo-2-hydroxy-3-naphthoate and 90 weight percent of AEROSIL.RTM. 
R972. The formed white powder charge additive composite, 0.063 gram, was 
then added together with 12.5 grams of an experimental toner, 9 microns in 
average volume diameter, comprised of 100 percent of styrene butadiene 
(89/11), to a 4 ounce bottle containing 125 grams of steel shot of 1/4 
inch diameter and the bottle was the roll milled for 30 minutes. 
Developer Preparation 
A developer composition was then prepared by adding 1.25 grams of the above 
prepared toner and 60 grams of steel core carrier, 130 microns in 
diameter, and 0.8 percent by weight of a surface coating of 
polymethylmethacrylate with 20 weight percent of KYNAR.RTM., to a roll 
mill where mixing was accomplished for 60 minutes at a speed of about 90 
feet per minute to generate a time zero developer. The tribo of the 
resulting toner as determined by the known Faraday Cage method at 20% RH 
was -68 microcoulombs per gram, and the admix rate was 15 seconds as 
determined in the known charge spectrograph. 
EXAMPLE III 
There was prepared a surface-treated silica consisting of 10% by weight of 
2-hydroxy-3-naphthoic acid and 90% of AEROSIL.RTM. R972 using the process 
described in Example II. The surface-treated silica was then incorporated 
into toner and developer using the formulation and evaluation procedures 
of Example II. The tribo of the toner is -75 .mu.C/g and the admix time 
was 5 minutes as determined in the known charge spectrograph. 
COMATIVE EXAMPLE I 
The processes of Example II were repeated except that there was selected as 
the toner charge additive LR120 (from Japan Carlit, potassium 
bis(3,5-di-t-butylsalicyato borate)) in place of the sodium 
1,6-dibromo-2-hydroxy-3-naphthoate. The toner tribo was -41 .mu.C/g and 
the admix was 5 minutes. The charge additives of Examples I and II 
consistently gave higher tribo with improved admix properties compared to 
the results of this Example. 
EXAMPLE IV 
A model toner consisting of 0.1% by weight of 
1,6-dibromo-2-hydroxy-3-naphthoic acid applied directly on the surface of 
the 9 micron styrene/butadiene (89/11) toner was prepared by the 
aforementioned solution coating technique. Specifically, a 9 micron 
styrene/butadiene (89/11) toner, 12.5 g, was added to a methanol solution 
coating 0.125 g of 1,6-dibromo-2-hydroxy-3-naphthoic acid in 100 mL of 
methanol. After stirring the mixture for half an hour, the solvent was 
removed on an evaporator and the resulting toner was vacuum dried at room 
temperature for 16 hours. Two developers were prepared using the 
formulation in Example I and they were each separately placed in a 
glove-box and equilibrated at 20% RH and 80% RH, respectively. The tribos 
of these toners determined as described in Example I were -28 and -45 
microC/g, respectively. 
The results indicated that the charge additives of the present invention do 
not lose their charging ability or chargability at high RH. 
EXAMPLE V 
Another model toner consisting of 0.1% by weight of 2-hydroxy-3-naphthoic 
acid on the surface of a 9 micron styrene/butadiene (89/11) toner was 
prepared and tested using the procedures described in Example IV. The 
tribo results were as follows: 
______________________________________ 
20% RH tribo 80% RH tribo 
______________________________________ 
-18.8 microC/g -34.9 microC/g 
______________________________________ 
EXAMPLE VI 
A model toner consisting of 0.1% by weight of 2,8-dihydroxy-3-naphthoic 
acid on the surface of a 9 micron styrene/butadiene (89/11) toner was 
prepared and tested according to procedures described in Example IV. The 
toner tribo results were as follows: 
______________________________________ 
20% RH 80% RH 
______________________________________ 
-34.2 microC/g -44.6 microC/g 
______________________________________ 
The above mentioned patents and publications are incorporated by reference 
herein in their entirety. 
Other modifications of the present invention may occur to those skilled in 
the art subsequent to a review of the present application, and these 
modifications, including equivalents thereof, are intended to be included 
within the scope of the present invention.