CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Disclosed in copending application
U.S. Serial No. 10/606,330, filed June 25, 2003, the disclosure of which is totally incorporated herein by reference, is a toner
process comprised of heating a mixture of an acicular magnetite dispersion, a colorant
dispersion, a wax dispersion, a first latex containing a crosslinked resin, and a
second latex containing a resin free of crosslinking in the presence of a coagulant
to provide aggregates, stabilizing the aggregates with a silicate salt dissolved in
a base, and further heating said aggregates to provide coalesced toner particles.
[0002] Illustrated in copending application
U.S. Serial No. 10/606,298, filed June 25, 2003, the disclosure of which is totally incorporated herein by reference, is a toner
process comprised of a first heating of a mixture of an aqueous colorant dispersion,
an aqueous latex emulsion, and an aqueous wax dispersion in the presence of a coagulant
to provide aggregates, adding a base followed by adding an organic sequestering agent,
and thereafter accomplishing a second heating, and wherein said first heating is below
about the latex polymer glass transition temperature (Tg), and said second heating
is about above the latex polymer glass transition temperature.
[0003] Illustrated in copending application
U.S. Serial No. 10/603,449, filed June 25, 2003, the disclosure of which is totally incorporated herein by reference, is a toner
process comprised of a first heating of a colorant dispersion, a latex emulsion, and
a wax dispersion in the presence of a coagulant containing a metal ion; adding a complexing
compoundte salt; followed by a second heating.
[0004] Illustrated in copending application
U.S. Serial No. 10/603,321, filed June 25, 2003, the disclosure of which is totally incorporated herein by reference, is a toner
process comprised of heating a mixture of an acicular magnetite dispersion, a colorant
dispersion, a wax dispersion, a first latex containing a crosslinked resin, a second
latex containing a resin substantially free of crosslinking, a coagulant and a complexing
compound, and wherein the toner resulting possesses a shape factor of from about 120
to about 150.
[0005] Illustrated in
U.S. Patent 6,617,092, the disclosure of which is totally incorporated herein by reference, is a process
for the preparation of a magnetic toner comprising heating a colorant dispersion containing
acicular magnetite, a carbon black dispersion, a latex emulsion, and a wax dispersion.
[0006] Illustrated in
U.S. Patent 6,627,373, the disclosure of which is totally incorporated herein by reference, is a process
for the preparation of a magnetic toner comprising the heating of a colorant dispersion
comprised of a magnetite dispersion, and a carbon black dispersion, and thereafter
mixing with a basic cationic latex emulsion and a wax dispersion.
[0007] Illustrated in
U.S. Patent 6,541,175, filed February 4, 2002 on Toner Processes, the disclosure of which is totally incorporated herein by reference,
is a process comprising:
- (i) providing or generating an emulsion latex comprised of sodio sulfonated polyester
resin particles by heating the particles in water at a temperature of from about 65°C
to about 90°C;
- (ii) adding with shearing to the latex (i) a colorant dispersion comprising from about
20 percent to about 50 percent of a predispersed colorant in water, followed by the
addition of an organic or an inorganic acid;
- (iii) heating the resulting mixture at a temperature of from about 45°C to about 65°C
followed by the addition of a water insoluble metal salt or a water insoluble metal
oxide thereby releasing metal ions and permitting aggregation and coalescence, optionally
resulting in toner particles of from about 2 to about 25 microns in volume average
diameter; and optionally
- (iv) cooling the mixture and isolating the product.
[0008] Illustrated in copending application
U.S. Serial No. 10/106,473 on Toner Processes, filed March 25, 2002, Publication No. 20030180648, the disclosure
of which is totally incorporated herein by reference, is a process for the preparation
of a toner comprising mixing a colorant dispersion comprising an acicular magnetite
dispersion and a carbon black dispersion with a latex, a wax dispersion and a coagulant.
[0009] Illustrated in
U.S. Patent 6,656,658, the disclosure of which is totally incorporated herein by reference, is a toner
process comprising heating a mixture of an acidified dispersion of an acicular magnetite
with a colorant dispersion of carbon black, a wax dispersion, and an acidic latex
emulsion.
[0010] Illustrated in U.S Patent 6,656,657, the disclosure of which is totally incorporated
herein by reference, is a toner process comprising heating an acidified dispersion
of an acicular magnetite with an anionic latex, an anionic carbon black dispersion,
and an anionic wax dispersion.
[0011] Illustrated in
U.S. Patent 6,495,302, filed June 11, 2001 on Toner Coagulant Processes, the disclosure of which is totally incorporated herein
by reference, is a process for the preparation of toner comprising
- (i) generating a latex emulsion of resin, water, and an ionic surfactant, and a colorant
dispersion of a colorant, water, an ionic surfactant, or a nonionic surfactant, and
wherein
- (ii) the latex emulsion is blended with the colorant dispersion;
- (iii) adding to the resulting blend containing the latex and colorant a coagulant
of a polyaluminum chloride with an opposite charge to that of the ionic surfactant
latex colorant;
- (iv) heating the resulting mixture below or equal to about the glass transition temperature
(Tg) of the latex resin to form aggregates;
- (v) optionally adding a second latex comprised of submicron resin particles suspended
in an aqueous phase (iv) resulting in a shell or coating wherein the shell is optionally
of from about 0.1 to about 1 micron in thickness, and wherein optionally the shell
coating is contained on 100 percent of the aggregates;
- (vi) adding an organic water soluble or water insoluble chelating component to the
aggregates of (v) particles, followed by adding a base to change the resulting toner
aggregate mixture from a pH which is initially from about 1.9 to about 3 to a pH of
about 5 to about 9;
- (vii) heating the resulting aggregate suspension of (vi) above about the Tg of the
latex resin;
- (viii) optionally retaining the mixture (vii) at a temperature of from about 70°C
to about 95°C;
- (ix) changing the pH of the (viii) mixture by the addition of an acid to arrive at
a pH of about 1.7 to about 4; and
- (x) optionally isolating the toner.
[0012] Illustrated in
U.S. Patent 6,500,597, filed August 6, 2001 on Toner Coagulant Processes, the disclosure of which is totally incorporated herein
by reference, is a process comprising
- (i) blending a colorant dispersion of a colorant, water, and an anionic surfactant,
or a nonionic surfactant with
- (ii) a latex emulsion comprised of resin, water, and an ionic surfactant;
- (iii) adding to the resulting blend a first coagulant of polyaluminum sulfosilicate
(PASS) and a second cationic co-coagulant having an opposite charge polarity to that
of the latex surfactant;
- (iv) heating the resulting mixture below about the glass transition temperature (Tg)
of the latex resin;
- (v) adjusting with a base the pH of the resulting toner aggregate mixture from a pH
which is in the range of about 1.8 to about 3 to a pH range of about 5 to about 9;
- (vi) heating above about the Tg of the latex resin;
- (vii) changing the pH of the mixture by the addition of a metal salt to arrive at
a pH of from about 2.8 to about 5; and
- (viii) optionally isolating the product.
[0013] Illustrated in
U.S. Patent 6,576,389, filed October 15, 2001 on Toner Coagulant Processes, the disclosure of which is totally incorporated herein
by reference, is a process for the preparation of toner comprising mixing a colorant
dispersion, a latex emulsion, a wax dispersion and coagulants comprising a colloidal
alumina coated a complexing compound, and a polymetal halide.
[0014] Illustrated in
U.S. Patent 6,767,684, the disclosure of which is totally incorporated herein by reference, is a toner
process comprising mixing a colorant dispersion comprising an acicular magnetite dispersion
and a colorant with a latex containing a crosslinked resin, a latex containing a resin
free of crosslinking, a wax dispersion, a resin, and a coagulant.
[0015] The appropriate components, such as for example, magnetites, waxes, coagulants, resin
latexes, surfactants, and colorants, and processes of the above copending applications
may be selected for the present invention in embodiments thereof.
BACKGROUND
[0016] Illustrated herein are toner processes, and more specifically, aggregation and coalescence
processes. More specifically, the present invention relates in embodiments to methods
for the preparation of toner compositions by a chemical process, such as emulsion/aggregation/coalescence,
wherein latex particles are aggregated with a wax and a crosslinked gel wherein the
gel or crosslinking value is, for example, from about 20 to about 55 percent as measured
gravimetrically; colorants, and a magnetite in the presence of a coagulant like a
polymetal halide, or alternatively a mixture of coagulants or flocculating agents;
thereafter stabilizing the aggregates with an organic complexing agent or a chelating
agent, such as ethylenediaminetetraacetic acid (EDTA) dissolved in a base, such as
sodium hydroxide, and thereafter coalescing or fusing by heating the mixture above
the resin Tg to provide toner size particles which when developed by an electrographic
process generates documents suitable for magnetic image character. In embodiments
illustrated herein the chelating agent or compound allows the toner aggregates formed
comprised, for example, of magnetite and metal coagulant ions like aluminum, for the
formation of water soluble complexes which prevents or minimizes undesired interaction
of magnetite or iron particles. The point of zero charge (Pzc) of magnetite and its
relationship to pH and to temperature is illustrated, for example, in copending application
U.S. Serial No. 10/106,473, Publication No.
20030180648, the disclosure of which is totally incorporated herein by reference. By utilizing
complexing or chelating compounds, the Pzc can be altered and thereby also minimize
the generation of charges which may interfere in the toner emulsion aggregation process.
[0017] A number of advantages are associated with the present invention in embodiments thereof
including, for example, excellent toner hot offset, for example above about 210°C,
and more specifically, from about 210°C to about 230°C; a toner fusing latitude of
from about 20°C to about 40°C wherein fusing latitude refers to a temperature in which,
when a developed image is fused, evidences substantially no offset either to the substrate
that the image is fused on, referred to as "Cold" offset or an offset on the fuser
roll referred to as the "Hot" offset; a minimum fixing temperature of, for example,
about 170°C to about 195°C; and extended photoreceptor life since the toner fusing
temperature can be below about 195°C, such as from about 175°C to about 190°C; stable,
controllable and substantially predictable PCZ, (point of zero charge), and wherein
the charge on the magnetite particles can be either positive or negative depending,
for example, on the pH of the medium, that is when the pH is acidic there results
a positive charge; when the pH is basic there results negative charge, such as lowering
the point of zero charge, for example from a value of 5.4 to about 3.5 of the complexed
magnetite thereby enabling, for example, coalescence of the aggregates; and also in
embodiments a process that enables a means of identifying how a toner was fabricated
by, for example, analyzing for aluminum and organic complexing compound content.
REFERENCES
[0018] In
U.S. Patent 6,132,924, the disclosure of which is totally incorporated herein by reference, there is illustrated
a process for the preparation of toner comprising mixing a colorant, a latex, and
a coagulant, followed by aggregation and coalescence, wherein the coagulant may be
a polyaluminum chloride.
[0019] In
U.S. Patent 6,268,102, the disclosure of which is totally incorporated herein by reference, there is illustrated
a process for the preparation of toner comprising mixing a colorant, a latex, and
a coagulant, followed by aggregation and coalescence, and wherein the coagulant may
be a polyaluminum sulfosilicate.
[0020] Also, in
U.S. Patent 6,416,920, the disclosure of which is totally incorporated herein by reference, there is illustrated
a process for the preparation of toner comprising mixing a colorant, a latex, and
a complexing compound, which a complexing compound is coated with an alumina.
[0021] Magnetic ink printing methods with inks containing magnetic particles are known.
For example, there is disclosed in
U.S. Patent 3,998,160, the disclosure of which is totally incorporated herein by reference, that various
magnetic inks have been used in printing digits, characters, or artistic designs on
checks or bank notes. The magnetic ink used for these processes can contain, for example,
magnetic particles, such as a magnetite in a fluid medium, and a magnetic coating
of ferric oxide, chromium dioxide, or similar materials dispersed in a vehicle comprising
binders, and plasticizers.
[0022] Disclosed in
U.S. Patent 4,128,202, the disclosure of which is totally incorporated herein by reference, is a device
for transporting a document that has been mutilated or erroneously encoded, and wherein
there is provided a predetermined area for the receipt of correctly encoded magnetic
image character recognition information (MICR). As indicated in this patent, the information
is referred to as MICR characters, which characters can appear, for example, at the
bottom of personal checks as printed numbers and symbols. These checks have been printed
in an ink containing magnetizable particles therein, and when the information contained
on the document is to be read, the document is passed through a sorter/reader which
first magnetizes the magnetizable particles, and subsequently detects a magnetic field
of the symbols resulting from the magnetic retentivity of the ink. The characters
and symbols involved, according to the '202 patent, are generally segregated into
three separate fields, the first field being termed a transient field, which contains
the appropriate symbols and characters to identify the bank, bank branch, or the issuing
source.
[0023] In
U.S. Patent 5,914,209, the disclosure of which is totally incorporated by reference, there is illustrated
a process for preparing MICR toners using a combination of hard and soft magnetites,
and a lubricating wax and melt mixing with a resin followed by jetting and classifying
the blend to provide toner compositions.
[0024] In
U.S. Patent 4,517,268, the disclosure of which is totally incorporated by reference, there is illustrated
a process for preparing MICR toners using styrene copolymers, such as styrene butadiene,
by melt mixing in a Banbury apparatus, followed by pulverizing the magnetite and the
resin, followed by jetting and classifying to provide, for example, 10 to 12 micron
toner size particles which when mixed with an additive package and a carrier provides
a developer suitable for use in the Xerox Corporation 9700
®.
[0025] Further patents relating to MICR processes are
4,859,550;
5,510,221; and
5,034,298, illustrating, for example, the generation of MICR toners by conventional means such
as that described in
U.S. Patent 4,517,268.
[0026] In applications requiring MICR capabilities, the toners selected usually contain
magnetites having specific properties, an important one of which is a high enough
level of remanence or retentivity. Retentivity is a measure of the magnetism left
when the magnetite is removed from the magnetic field, that is, the residual magnetism.
Also of value are toners with a high enough retentivity, such that when the characters
are read, the magnetites produce a signal strength of equal to greater than about
100 percent. The signal level can vary in proportion to the amount of toner deposited
on the document being generated, and signal strength of a toner composition can be
measured by using known devices, including the MICR-Mate 1, manufactured by Checkmate
Electronics, Inc.
[0027] In
U.S. Patent 5,780,190, the disclosure of which is totally incorporated herein by reference, there is disclosed
an ionographic process which comprises the generation of a latent image comprised
of characters; developing the image with an encapsulated magnetic toner comprised
of a core comprised of a polymer and a soft magnetite, and wherein the core is encapsulated
within a polymeric shell; and subsequently providing the developed image with magnetic
ink characters thereon to a reader/sorter device.
[0028] Emulsion/aggregation/coalescing processes for the preparation of toners are illustrated
in a number of Xerox patents, the disclosures of which are totally incorporated herein
by reference, such as
U.S. Patent 5,290,654,
U.S. Patent 5,278,020,
U.S. Patent 5,308,734,
U.S. Patent 5,370,963,
U.S. Patent 5,344,738,
U.S. Patent 5,403,693,
U.S. Patent 5,418,108,
U.S. Patent 5,364,729, and
U.S. Patent 5,346,797; and also of interest may be
U.S. Patents 5,348,832;
5,405,728;
5,366,841;
5,496,676;
5,527,658;
5,585,215;
5,650,255;
5,650,256 and
5,501,935;
5,723,253;
5,744,520;
5,763,133;
5,766,818;
5,747,215;
5,827,633;
5,853,944;
5,804,349;
5,840,462;
5,869,215;
5,869,215;
5,863,698;
5,902,710;
5,910,387;
5,916,725;
5,919,595;
5,925,488 and
5,977,210. The components and processes of these Xerox patents can be selected for the present
invention in embodiments thereof.
[0029] In addition, the following U.S. Patents relate to emulsion aggregation toner processes,
the disclosures of which are totally incorporated herein by reference.
[0030] U.S. Patent 5,922,501, the disclosure of which is totally incorporated herein by reference, illustrates
a process for the preparation of toner comprising blending an aqueous colorant dispersion
and a latex resin emulsion, and which latex resin is generated from a dimeric acrylic
acid, an oligomer acrylic acid, or mixtures thereof and a monomer; heating the resulting
mixture at a temperature about equal, or below about the glass transition temperature
(Tg) of the latex resin to form aggregates; heating the resulting aggregates at a
temperature about equal to, or above about the Tg of the latex resin to effect coalescence
and fusing of the aggregates; and optionally isolating the toner product, washing,
and drying.
[0031] U.S. Patent 5,945,245, the disclosure of which is totally incorporated herein by reference, illustrates
a surfactant free process for the preparation of toner comprising heating a mixture
of an emulsion latex, a colorant, and an organic complexing agent.
SUMMARY
[0032] The present invention provides:
- (1) a toner process comprised of heating a mixture of an acicular magnetite dispersion,
a colorant dispersion, a wax dispersion, a first latex containing a crosslinked resin,
and a second latex containing a resin free of crosslinking in the presence of a coagulant
to provide aggregates, stabilizing the aggregates with an organic complexing compound
or salt thereof substantially dissolved in a base, and further heating said aggregates
to provide coalesced toner particles;
- (2) a process in accordance with (1) wherein an organic complexing compound is incorporated
in said toner by an in situ method;
- (3) a process in accordance with (2) wherein said complexing compound is selected
in an amount of from about 0.5 to about 2 percent by weight of toner.;
- (4) a process in accordance with (1) comprising
- (i) mixing said acicular magnetite dispersion containing water and an anionic surfactant,
and said colorant dispersion containing carbon black, water, and an anionic surfactant,
and optionally a nonionic surfactant, and wherein said wax dispersion is comprised
of submicron wax particles of from about 0.1 to about 0.5 micron in diameter by volume,
and which wax is dispersed in water and contains an anionic surfactant to provide
a mixture containing magnetite, colorant, and a wax;
- (ii) wherein the resulting mixture is blended with said first and second latex, said
first latex comprising submicron noncrosslinked resin particles of about 150 to about
300 nanometers in diameter containing water, an anionic surfactant or a nonionic surfactant,
and wherein said second latex comprises submicron crosslinked gel particles of about
30 to about 150 nanometers in diameter, and containing water and an anionic surfactant
or a nonionic surfactant;
- (iii) wherein the resulting blend of (ii) possesses a pH of about 2.2 to about 2.8,
and to which is added a coagulant to initiate flocculation or aggregation of said
resulting components;
- (iv) heating the resulting mixture of (iii) below about the glass transition temperature
(Tg) of the resin free of crosslinking to form aggregates;
- (v) adding to the formed aggregates a latex comprised of a noncrosslinked resin suspended
in an aqueous phase containing an ionic surfactant and water;
- (vi) adding to the resulting mixture of (v) an aqueous solution of said complexing
compound salt dissolved in a base to thereby change the pH, which is initially from
about 2 to about 2.8, to arrive at a pH of from about 7 to about 7.4 resulting in
a coating of said complexing compound on the aggregate particles containing magnetite;
- (vii) heating the resulting mixture of (vi) above about the Tg of the noncrosslinked
resin of (i) and allowing the pH to decrease;
- (viii) retaining the mixture of (vii) at a temperature of from about 85°C to about
95°C for an optional period of about 10 to about 60 minutes, followed by a pH reduction
with an acid to arrive at a pH of from about 4.2 to about 4.8, which pH is below about
the Pzc of the magnetite particles wherein the Pzc is the pH of the mixture particles
when said particles are free of a positive or a negative charge, and optionally wherein
an increase in temperature results in a decreased Pzc value;
- (ix) retaining the mixture temperature at from about 85°C to about 95°C for an optional
period of about 5 to about 10 hours to assist in permitting the fusion or coalescence
of the toner aggregates and to obtain smooth particles;
- (x) washing the resulting toner slurry;
- (xi) isolating the formed toner particles, and drying;
- (5) a process in accordance with (4) wherein said complexing compound salt dissolved
in said base is introduced at (vi), and wherein said complexing compound reacts with
said magnetite rendering said magnetites substantially insensitive to pH fluctuations,
and resulting in the magnetite Point of Zero Charge (Pzc) being substantially ineffective;
- (6) a process in accordance with (4) wherein the Pzc of said magnetite is altered
by said complexing compound, which complexing compound and said coagulant is a polymetal
halide;
- (7) a process in accordance with (4) (viii) wherein said pH is decreased to about
4.5, said pH being lower than that of said magnetite which is at a pH of about 5.3;
- (8) a process in accordance with (1) wherein said base is sodium hydroxide, or potassium
hydroxide;
- (9) a process in accordance with (2) wherein from about 75 to about 95 percent of
said complexing compound is introduced and retained in the toner surface;
- (10) a process in accordance with (2) wherein said coagulant is selected from the
group consisting of polyaluminum chloride (PAC), polyaluminum sulfosilicate (PASS),
aluminum sulfate, zinc sulfate, and magnesium sulfate, and optionally wherein from
about 80 to about 90 percent of said coagulant metal ion is retained in said toner;
- (11) a process in accordance with (1) wherein said colorant is carbon black, and wherein
said carbon black dispersion comprises carbon black particles of from about 0.01 to
about 0.2 micron diameter dispersed in water and an anionic surfactant, and wherein
said colorant is present in an amount of from about 4 to about 10 weight percent,
and optionally wherein the amount of acicular magnetite selected is from about 20
to about 40 percent by weight of toner, said colorant is carbon black present in the
amount of from about 4 to about 8 percent by weight of toner, and said wax is present
in the amount of about 4 to about 12 percent by weight of toner; said crosslinked
resin is present in the amount of about 5 to about 10 percent by weight; said uncrosslinked
resin is present in an amount of about 55 to about 65 percent by weight of toner;
and said coagulant is comprised of polymetal halide present in an amount of about
0.02 to about 2 percent by weight of toner;
- (12) a process in accordance with (1) wherein said acicular magnetite is from about
0.6 to about 0.1 micron in average volume diameter and is selected in an amount of
from about 23 to about 35 percent by weight of toner, and wherein said coagulant is
a polymetal halide selected in an amount of about 0.05 to about 0.15 percent by weight
of toner, and optionally wherein said acicular magnetite possesses a coercivity of
from about 250 to about 500 Oe, a remanent magnetization (Br) of about 23 to about
39 emu/gram, a saturation magnetization (Bm) of about 70 to about 90 emu/gram, and
a magnetic signal of about 90 to about 150 percent of the nominal where the nominal
is a signal strength of about 100 percent;
- (13) a process in accordance with (1) wherein the crosslinked resin contains resin
particles of from about 0.15 to about 0.4 micron in volume average diameter, and said
second latex contains a resin free of crosslinking of a diameter of about 0.15 to
about 0.4 micron;
- (14) a process in accordance with (4) wherein said acid is nitric, sulfuric, hydrochloric,
citric or acetic acid, and said coagulant is a polyaluminum chloride;
- (15) a process in accordance with (4) (v) wherein said noncrosslinked resin is comprised
of submicron particles suspended in said aqueous phase containing an anionic surfactant,
and wherein said noncrosslinked resin is selected in an amount of from about 10 to
about 40 percent by weight of the initial latex (i) to form a shell thereover on said
formed aggregates, and which shell is of an optional thickness of about 0.2 to about
0.8 micron, and optionally wherein said coagulant is a polymetal halide;
- (16) a process in accordance with (4) wherein the pH of the mixture resulting in (vi)
is increased from about 2 to about 2.6 to about 7 to about 7.5, and wherein said complexing
compound salt dissolved in a base functions primarily as a stabilizer for the aggregates
during coalescence (vii), and no or minimal toner particle size increase results,
and wherein said coagulant is a polymetal halide, and wherein the aggregation (iv)
temperature is from about 45°C to about 60°C, and wherein the coalescence or fusion
temperature of (vii) and (viii) is from about 80°C to about 95°C, and wherein said
coagulant is a polyaluminum halide; and optionally, wherein the time of coalescence
or fusion is from about 6 to about 12 hours, and wherein the toner resulting possesses
a smooth morphology;
- (17) a process in accordance with (1) wherein said second latex contains a resin selected
from the group comprised of poly(styrene-alkyl acrylate), poly(styrene-1,3-diene),
poly(styrene-alkyl methacrylate), poly(alkyl methacrylate-alkyl acrylate), poly(alkyl
methacrylate-aryl acrylate), poly(aryl methacrylate-alkyl acrylate), poly(alkyl methacrylate),
poly(styrene-alkyl acrylate-acrylonitrile), poly(styrene-1,3-diene-acrylonitrile),
poly(alkyl acrylate-acrylonitrile), poly(styrenebutadiene), poly(methylstyrene-butadiene),
poly(methyl methacrylate-butadiene), poly(ethyl methacrylate-butadiene), poly(propyl
methacrylate-butadiene), poly(butyl methacrylate-butadiene), poly(methyl acrylate-butadiene),
poly(ethyl acrylate-butadiene), poly(propyl acrylate-butadiene), poly(butyl acrylate-butadiene),
poly(styrene-isoprene), poly(methylstyrene-isoprene), poly(methyl methacrylate-isoprene),
poly(ethyl methacrylate-isoprene), poly(propyl methacrylate-isoprene), poly(butyl
methacrylate-isoprene), poly(methyl acrylate-isoprene), poly(ethyl acrylate-isoprene),
poly(propyl acrylate-isoprene), poly(butyl acrylate-isoprene), poly(styrene-propyl
acrylate), poly(styrene-butyl acrylate), poly(styrene-butadiene-acrylonitrile), and
poly(styrene-butyl acrylate-acrylononitrile);
- (18) a process in accordance with (1) wherein said second latex contains a resin of
a carboxylic acid selected from the group comprised of acrylic acid, methacrylic acid,
itaconic acid, beta carboxy ethyl acrylate, fumaric acid, maleic acid, and cinnamic
acid, and wherein said carboxylic acid is selected in an amount of from about 0.1
to about 10 weight percent; and wherein said acicular magnetite possesses a coercivity
of about 250 to about 700 Oe, a particle size of about 0.6 micron in length x 0.1
micron in diameter, a coercivity of from about 250 to about 500 Oe, a remanent magnetization
(Br) of about 23 to about 39 emu/gram, and a saturation magnetization (Bm) of about
70 to about 90 emu/gram; a coercivity of about 345 Oe, a remanent magnetization (Br)
of about 35 emu/gram, and a saturation magnetization (Bm) of about 85 emu/gram; a
coercivity of about 370 Oe, a remanent magnetization (Br) of about 33 emu/gram, and
a saturation magnetization (Bm) of about 83 emu/gram; a magnetite with a coercivity
of about 270 Oe, a remanent magnetization (Br) of about 20 emu/gram, and a saturation
magnetization (Bm) of about 79 emu/gram; a coercivity of from about 250 to about 400
Oe, a remanent magnetization (Br) of about 23 to about 55 emu/gram, and a saturation
magnetization (Bm) of about 70 to about 90 emu/gram; and wherein said acicular magnetite
is present in said toner in an amount of from about 10 to about 40 weight percent;
or wherein said acicular magnetite possesses a coercivity of about 250 to about 700
Oe, a particle size of about 0.6 micron in length x 0.1 micron in diameter, a magnetite
with a coercivity of from about 250 to about 500 Oe, a remanent magnetization (Br)
of about 23 to about 39 emu/gram, and a saturation magnetization (Bm) of about 70
to about 90 emu/gram; and wherein said wax is a polyethylene, a polypropylene, or
mixtures thereof, and said colorant is carbon black;
- (19) a process in accordance with (1) wherein said wax dispersion contains a polyethylene
wax, a polypropylene wax or mixtures thereof, water, and an anionic surfactant; and
wherein said wax is selected in an amount of from about 5 to about 20 weight percent;
- (20) a process in accordance with (1) wherein said first latex contains a crosslinked
resin in an amount of from about 2 to about 25 weight percent; and wherein said crosslinked
resin possesses a molecular weight Mw of from about 100,000 to about 1,000,000, and an onset glass transition (Tg) temperature
of about 48°C to about 58°C, and optionally wherein said crosslinked resin is poly(styrene
butylacrylate, beta carboxy ethyl acrylate divinyl benzene);
- (21) a process in accordance with (1) wherein said resin free of crosslinking possesses
a molecular weight Mw of about 20,000 to about 500,000, and an onset glass transition (Tg) temperature
of from about 45°C to about 55°C;
- (22) a toner process comprised of heating a mixture of an acicular magnetite dispersion,
a colorant dispersion, a first latex containing a crosslinked resin, and a second
latex containing a resin free of crosslinking in the presence of a coagulant; adding
a complexing compound salt dissolved in a base, and further heating said aggregates
to provide coalesced toner particles;
- (23) a process comprising heating a mixture of magnetite, colorant, a first latex,
and a second latex wherein the first latex contains a crosslinked polymer and the
second latex is substantially free of a crosslinked polymer, and which heating is
accomplished in the presence of a coagulant and a complexing compound salt base mixture,
and wherein said heating comprises a first and second heating, which second heating
is at a higher temperature than said first heating, and wherein said first heating
is below about the glass transition temperature Tg of said resin free of crosslinking,
and said second heating is above about the Tg of said resin free of crosslinking;
- (24) a process in accordance with (23) wherein said complexing compound is ethylenediamine
tetraacetic acid (EDTA), gluconal, sodium gluconate, potassium and sodium citrate,
nitrotriacetate (NTA) salt, GLDA (commercially available L-glutamic acid N,N diacetic
acid) humic and fulvic acids, maltol and ethyl-maltol, peta-acetic and tetra-acetic
acids; or the corresponding salts thereof;
- (25) a process in accordance with (23) wherein said complexing compound is ethylenediamine
tetraacetic acid, or diethylenetriaminepentacetic acid;
- (26) a process in accordance with (23) wherein said complexing compound is the corresponding
salt thereof, and wherein said salt is the sodium salt, or potassium salt; and
- (27) a xerographic imaging process comprising generating an electrostatic image on
a photoconductive member, and developing said image with the toner obtained by the
process of (1).
[0033] A feature illustrated herein relates to the provision of a toner with a number of
the advantages illustrated herein, and more specifically, a complexing compound coated
magnetite containing toner for Magnetic Ink Character Recognition (MICR) processes
by, for example, selecting specific magnetites that provide an acceptable readability
signal by a check reader, and wherein the resulting toners possess a sufficient magnetic
signal, desirable melt fusing, hot offset, and fusing latitude temperatures, and which
toners also contain a gel or a crosslinked resin.
[0034] In another feature, there is provided a process for the preparation of a MICR toner,
wherein resins, pigment and wax are aggregated in the presence of a coagulant, such
as polymetal halides or polymetal sulfosilicate, to provide toner size aggregates
which can then be stabilized, for example with substantially no increase in size,
by introducing an organic complexing or chelating compound in the presence of a base
and further heating to provide toners with narrow particle size distribution.
[0035] Aspects of the present invention relate to a toner process comprised of heating a
mixture of an acicular magnetite dispersion, a colorant dispersion, a wax dispersion,
a first latex containing a crosslinked resin, and a second latex containing a resin
substantially free of or free of crosslinking in the presence of a coagulant to provide
aggregates, stabilizing the aggregates with an organic complexing or chelating compound
dissolved in a base, and further heating the aggregates to provide coalesced toner
particles; a toner process comprised of heating a mixture of an acicular magnetite
dispersion, a colorant dispersion, a first latex containing a crosslinked resin, and
a second latex containing a resin free of crosslinking in the presence of a coagulant;
above the latex resin Tg adding a complexing compound salt dissolved in a base, and
further heating said aggregates to provide coalesced toner particles; a process comprising
heating a mixture of magnetite, colorant, a first latex, and a second latex wherein
the first latex contains a crosslinked polymer and the second latex is free of a crosslinked
polymer, and which heating is accomplished in the presence of a coagulant and a complexing
compound salt base mixture, and wherein said heating comprises a first and second
heating, which second heating is at a higher temperature than said first heating,
and wherein said first heating is below the glass transition temperature Tg of said
resin free of crosslinking, and said second heating is above the Tg of said resin
free of crosslinking; a process comprising
- (i) mixing the acicular magnetite dispersion containing water and an anionic surfactant,
and the colorant dispersion containing carbon black, water, and an anionic surfactant,
and optionally a nonionic surfactant, and wherein the wax dispersion is comprised
of submicron wax particles of from about 0.1 to about 0.5 micron in diameter by volume,
and which wax is dispersed in water and contains an anionic surfactant to provide
a mixture containing magnetite, colorant, and a wax;
- (ii) wherein the resulting mixture is blended with the first and a second latex, the
first latex comprising submicron noncrosslinked resin particles of about 150 to about
300 nanometers in diameter containing water, an anionic surfactant or a nonionic surfactant,
and wherein the second latex comprises submicron crosslinked gel particles of about
30 to about 150 nanometers in diameter, and containing water and an anionic surfactant
or a nonionic surfactant;
- (iii) wherein the resulting blend of (ii) possesses a pH of about 2.2 to about 2.8,
and to which is added a coagulant to initiate flocculation or aggregation of the resulting
components;
- (iv) heating the resulting mixture of (iii) below about the glass transition temperature
(Tg) of the resin free of crosslinking to form aggregates;
- (v) adding to the formed aggregates a latex comprised of a noncrosslinked resin suspended
in an aqueous phase containing an ionic surfactant and water;
- (vi) adding to the resulting mixture of (v) an aqueous solution of a complexing or
chelating compound dissolved in a base to thereby change the pH, which is initially
from about 2 to about 2.8, to arrive at a pH of from about 7 to about 7.4 resulting
in a coating by the reaction of the metal ions, such as iron, and the complexing agent
on the aggregate particles containing magnetite;
- (vii) heating the resulting mixture of (vi) above about the Tg of the noncrosslinked
resin of (i) and allowing the pH to decrease;
- (viii) retaining the mixture of (vii) at a temperature of from about 85°C to about
95°C for an optional period of about 10 to about 60 minutes, followed by a pH reduction
with an acid to arrive at a pH of from about 4.2 to about 4.8, which pH is below about
the Pzc of the magnetite particles wherein the Pzc is the pH of the mixture particles
when the particles are free of a positive or a negative charge, and optionally wherein
an increase in temperature results in a decreased Pzc value;
- (ix) retaining the mixture temperature at from about 85°C to about 95°C for an optional
period of about 5 to about 10 hours to assist in permitting the fusion or coalescence
of the toner aggregates and to obtain smooth particles;
- (x) washing the resulting toner slurry;
- (xi) isolating the formed toner particles, and drying; a process wherein the reaction
between the complexing agent, such as EDTA, and the magnetite particle changes the
Pzc of from about 5.4 to about 3.5 (complexed magnetite particles); a toner process
comprised of heating a mixture of an acicular magnetite dispersion, a colorant dispersion,
a first latex containing a crosslinked resin, and a second latex containing a resin
free of crosslinking in the presence of a coagulant to provide aggregates, stabilizing
the aggregates with a complexing compound dissolved in a base, and further heating
the aggregates to provide coalesced toner particles; a process comprising heating
a mixture of magnetite, colorant, a first latex, and a second latex wherein the first
latex contains a crosslinked polymer and the second latex is substantially free of
a crosslinked polymer, and which heating is accomplished in the presence of a coagulant
and a complexing compound base mixture, and wherein the heating comprises a first
and second heating, which second heating is at a higher temperature than the first
heating, and wherein the first heating is below about the glass transition temperature
(Tg) of the polymer free of crosslinking resin, and the second heating is above about
the Tg of the resin free of crosslinking; the preparation of MICR toners wherein the
toner comprises magnetite, resin wax, a complexing compound and crosslinked gel particles
wherein a complexing compound is introduced in the form of a complexing compound substantially
dissolved in sodium hydroxide, and which solution possesses a pH of about 12, and
wherein a complexing compound binds or coats the magnetite or the aggregate particles
containing the magnetite thereby allowing the pH during coalescence to be lowered
below the Point of Zero Charge of the uncoated magnetite, for example equal to or
less than about 5.4; a process wherein the coating of a complexing compound on the
magnetite particles lowers the Pzc from a value of about 5.4 to about 3.5 enabling
the pH during coalescence to be reduced to about 4 to about 5 without any toner size
increase, thereby providing a broader process latitude and more rapid coalescence,
which coalescence can be reduced by about 40 percent; a toner process wherein there
is selected an organic complexing or chelating compound in the form of a complexing
compound salt, such as magnesium, iron, manganese, copper, cobalt, zinc, nickel, cadmium,
chromium, and aluminum which exhibit dual charge capabilities depending on the pH
of the surrounding media, allowing these particles to function as coagulating/flocculating
agents for an anionic or a cationic process, and wherein the addition of the complexing
compound forms a coating of thios compound on the magnetite aggregates thereby reducing
or lowering the Pzc, for example from about 5.3 to about 3.5; a toner process wherein
the toner formed can be of various shapes, such as a potato like shape to spherical
shape by, for example, reducing the pH during coalescence below a pH of 5; a MICR
toner containing the in situ incorporation of a complexing compound wherein the complexing
compound is introduced in the form of a complexing salt, which is dissolved in a base;
a MICR toner containing a complexing compound and prepared by emulsion aggregation
processes wherein the magnetite is in the form of needle shape or acicular magnetite
particles, which are of a size diameter of, for example, from about 450 nanometers
to about 700 nanometers; a toner process involving a complexing compound incorporation
by the introduction of an aqueous solution of a complexing compound dissolved in a
base, which base is introduced into an aggregate mixture prior to increasing the temperature
of the aggregate particles above the resin Tg to achieve coalescence or fusion; a
toner process that is capable of incorporating into toners needle shape or acicular
magnetites, which have a coercivity of about 350 oersteds (Oe), which is about 2 to
about 3 times that of cubic or spherical magnetite, which have a coercivity of about
110 oersteds, to provide an adequate magnetic signal, for example greater then 100
percent, where 100 percent refers, for example, to the nominal signal for readability
by a check reader; and the preparation of a MICR toner by emulsion aggregation processes
wherein the amount of acicular magnetite loading is about 23 to about 35 weight percent
of toner, or about 45 to about 65 weight percent to provide an adequate magnetic signal
for readability by a check reader; a process wherein
- (i) the acicular magnetite dispersion contains water and an anionic surfactant, or
a nonionic surfactant; the colorant dispersion of carbon black contains water and
an anionic surfactant, or a nonionic surfactant, and the wax dispersion is comprised
of submicron wax particles of from about 0.1 to about 0.5 micron in diameter by volume,
and which wax is dispersed in water and an anionic surfactant to provide a mixture
containing magnetite, colorant, and a wax;
- (ii) wherein the mixture of (i) is blended with a latex emulsion comprised of submicron
noncrosslinked resin particles in the size diameter range of about 150 to about 300
nanometers, and containing water, an anionic surfactant or a nonionic surfactant,
and a second latex comprised of submicron crosslinked gel particles in the size diameter
range of about 30 to about 150 nanometers containing water, and an anionic surfactant
or a nonionic surfactant to provide a blend of magnetite, colorant, wax and resins;
- (iii) wherein the resulting blend possesses a pH of about 2.2 to about 2.8 to which
is added a coagulant, such as a polymetal halide, to initiate flocculation or aggregation
of the blend components;
- (iv) heating the resulting mixture of (iii) below about the glass transition temperature
(Tg) of the latex resin to form toner sized aggregates;
- (v) adding to the formed toner aggregates a latex comprised of a noncrosslinked resin
suspended in an aqueous phase containing an ionic surfactant and water, and stirring
for a period of time to permit stabilization of the aggregate particle size;
- (vi) adding to the resulting mixture of (v) an aqueous solution, a complexing compound
substantially or completely dissolved in a base to thereby change the pH, which is
initially from about 2 to about 2.8, to arrive at a pH of from about 7 to about 7.4,
and allowing the mixture to stir for a period of about 5 to about 10 minutes to provide
a coating of a complexing compound on the aggregate particles containing magnetite;
- (vii) heating the resulting aggregate mixture of (vi) above about the Tg of the latex
containing the noncrosslinked resin of (i);
- (viii) retaining the mixture temperature at from about 85°C to about 95°C for an optional
period of about 10 to about 60 minutes, followed by a pH reduction with an acid to
arrive at a pH of about 4.2 to about 4.8, which pH is usually below the Pzc of the
magnetite particles;
- (ix) retaining the mixture temperature at from about 85°C to about 95°C for a period
of about 5 to about 10 hours to assist in permitting the fusion or coalescence of
the toner aggregates and to obtain smooth particles;
- (x) washing the resulting toner slurry;
- (xi) isolating the toner and drying; a process for the preparation of a MICR toner
composition, which when analyzed for aluminum and a complexing compound contents contains
about 70 to about 95 percent of both thereby providing a means of detection of how
the toner was fabricated; a toner composition comprised of magnetite, a noncrosslinked
latex, a crosslinked latex, wax, carbon black and a complexing compound which is incorporated
during particle fabrication as a coating rather than an external additive; a process
wherein the magnetite dispersion contains an anionic surfactant and a nonionic surfactant
wherever the dispersion possesses a pH of from about 6.5 to about 6.8; a process wherein
the carbon black dispersion comprises particles dispersed in water and an anionic
surfactant, and which dispersion possesses a pH of about 6.3 to about 6.8; a process
wherein the wax dispersion comprises particles dispersed in water and an ionic surfactant;
a process wherein the acicular magnetite is present in an amount of from about 20
to about 35 percent by weight of toner, and preferably in an amount of from about
23 to about 32 percent by weight of toner; a process wherein the acicular magnetite
utilized exhibits a coercivity of from about 250 to about 700 Oe; a process wherein
the acicular magnetite has a particle size of about 0.6 micron in length by 0.1 micron
in diameter, and is comprised of about 21 percent FeO and about 79 percent Fe2O3; a process wherein the toner exhibits a magnetic signal of from about 90 to about
150 percent of the nominal signal; a process wherein the toner possesses a minimum
fix temperature (MFT) of about 170°C to about 190°C; a process wherein the toner hot
offset temperature (HOT) is in excess of about 210°C; a process wherein the magnetite
dispersion is obtained by a ball milling, attrition, polytroning or media milling
resulting in magnetite particles dispersed in water containing an anionic surfactant;
a process wherein the carbon black dispersion is present in an amount of about 4 to
about 8 percent by weight of toner; a process wherein the latex resin particles are
from about 0.15 to about 0.3 micron in volume average diameter; a process wherein
the magnetite is of a size of about 0.6 micron to about 0.1 micron, and the carbon
black is of a size of about 0.01 to about 0.2 micron in average volume diameter; a
process wherein the acid is selected from the group consisting of nitric, sulfuric,
hydrochloric, citric and acetic acid; a process wherein the base is selected from
the group consisting of sodium hydroxide, potassium hydroxide and ammonium hydroxide;
a process wherein the addition of the a organic complexing compound in the form of
a salt of sodium, potassium or calcium is dissolved in the base which is added to
the toner size aggregates, which provides a coating of a complexing compound on the
aggregates containing the magnetite or the iron oxide particles, rendering it substantially
nonreactive, and stabilizes the toner size aggregates from further growth during coalescence,
or when the temperature of the aggregate mixture is raised above the resin Tg; a process
wherein there is added to the formed toner size aggregates a latex comprised of noncrosslinked
submicron resin particles suspended in an aqueous phase containing an anionic surfactant,
and wherein the noncrosslinked latex is selected in an amount of from about 10 to
about 40 percent by weight of the initial latex to form a shell on the formed aggregates,
and which shell is of a thickness of, for example, about 0.2 to about 0.8 micron;
a process wherein the added latex contains the same resin as the initial latex of
(i), or wherein the added latex contains a dissimilar resin than that of the initial
latex; a process wherein the pH of the mixture resulting in (vi) is increased from
about 2 to about 2.6 to about 7 to about 7.5 with the addition of the ethylenediaminetetraacetic
acid (EDTA) complexing compound dissolved in sodium hydroxide, which addition components
function as a stabilizer for the aggregates when the temperature of the coalescence
(vi) is raised above the resin Tg; a process wherein the addition of a basic, such
as sodium complexing compound, provides a reaction with iron oxide or magnetite thereby
allowing the pH during coalescence (viii) to be reduced to less than 5 to provide
MICR toners; a process wherein the temperature at which toner sized aggregates are
formed controls the size of the aggregates, and wherein the final toner size is from
about 5 to about 12 microns in volume average diameter; a process wherein the aggregation
(iv) temperature is from about 45°C to about 60°C, and wherein the coalescence or
fusion temperature of, for example, (vii) and (viii) is from about 85°C to about 95°C;
a process wherein the time of coalescence or fusion is from about 5 to about 10 hours,
and wherein there are provided toner particles with a smooth morphology; a process
wherein the latex contains a resin or polymer selected from the group consisting of
poly(styrene-alkyl acrylate), poly(styrene-1,3-diene), poly(styrene-alkyl methacrylate),
poly(styrene-alkyl acrylate-acrylic acid), poly(styrene-1,3-diene-acrylic acid), poly(styrene-alkyl
methacrylate-acrylic acid), poly(alkyl methacrylate-alkyl acrylate), poly(alkyl methacrylate-aryl
acrylate), poly(aryl methacrylate-alkyl acrylate), poly(alkyl methacrylate-acrylic
acid), poly(styrene-alkyl acrylate-acrylonitrile-acrylic acid), poly(styrene-1,3-diene-acrylonitrile-acrylic
acid), and poly(alkyl acrylate-acrylonitrile-acrylic acid); a process wherein the
latex contains a resin selected from the group consisting of poly(styrene-butadiene),
poly(methylstyrene-butadiene), poly(methyl methacrylate-butadiene), poly(ethyl methacrylate-butadiene),
poly(propyl methacrylate-butadiene), poly(butyl methacrylate-butadiene), poly(methyl
acrylate-butadiene), poly(ethyl acrylate-butadiene), poly(propyl acrylate-butadiene),
poly(butyl acrylate-butadiene), poly(styrene-isoprene), poly(methylstyrene-isoprene),
poly(methyl methacrylate-isoprene), poly(ethyl methacrylate-isoprene), poly(propyl
methacrylate-isoprene), poly(butyl methacrylate-isoprene), poly(methyl acrylate-isoprene),
poly(ethyl acrylate-isoprene), poly(propyl acrylate-isoprene), poly(butyl acrylate-isoprene),
poly(styrene-propyl acrylate), poly(styrene-butyl acrylate), polystyrene-butyl-acrylate
beta carboxy ethyl acrylate, poly(styrene-butadiene-acrylic acid), poly(styrene-butadiene-methacrylic
acid), poly(styrene-butadiene-acrylonitrile-acrylic acid), poly(styrene-butyl acrylate-acrylic
acid), poly(styrene-butyl acrylate-methacrylic acid), poly(styrene-butyl acrylate-acrylononitrile),
poly(styrene butyl acrylate (beta CEA), poly(styrene butadiene beta CEA), poly(styrene
isoprene beta CEA), poly(styrene butyl acrylate, acrylonitrile beta CEA), poly(styrene
butyl acrylate, divinylbenzene beta CEA), and poly(styrene-butyl acrylate-acrylononitrile-acrylic
acid), and more specifically, poly(styrene butyl acrylate beta CEA), and poly(styrene
butyl acrylate, divinylbenzene beta CEA), and yet more specifically, poly(styrene
butyl acrylate beta CEA); a process for the preparation of a MICR toner comprising
mixing
- (i) an acicular magnetite dispersion containing water and an anionic surfactant, and
a colorant dispersion of carbon black containing water, an anionic surfactant, and
a wax dispersion;
- (ii) wherein the mixture of (i) is blended with a latex emulsion comprised of submicron
noncrosslinked resin particles in the size range of about 150 to about 275 nanometers
and containing water, an anionic surfactant or a nonionic surfactant, and a second
latex comprised of submicron crosslinked polymer particles in the size range of about
30 to about 150 nanometers, and containing water and an anionic surfactant or a nonionic
surfactant;
- (iii) wherein the resulting blend possesses a pH of about 2.4 to about 2.7, and there
is added a cationic coagulant of a polyaluminum chloride to initiate flocculation
or aggregation of the components of (i) and (ii);
- (iv) heating the resulting mixture of (iii) below the glass transition temperature
(Tg) of the crosslinked resin latex to form toner sized aggregates;
- (v) adding to the formed toner aggregates a third latex comprised of a resin suspended
in an aqueous phase containing an ionic surfactant and water, and stirring for a period
of time to permit stabilization of the aggregate particle size;
- (vi) adding to the resulting mixture of (v) an aqueous solution of the complexing
compound dissolved in sodium hydroxide to thereby change the pH, which is initially
from about 2 to about 2.8, to arrive at a pH of from about 7 to about 7.4, and allowing
the mixture to stir for a period of about 5 to about 15 minutes causing the complexing
compound to react with the magnetite particles;
- (vii) heating the resulting aggregate suspension of (vi) above the Tg of the latex
noncrosslinked resin of (i);
- (viii) retaining the mixture temperature at from about 80°C to about 95°C for a period
of about 10 to about 75 minutes, followed by a pH reduction with an acid to arrive
at a pH of about 4 to about 4.8;
- (ix) retaining the mixture temperature at from about 80°C to about 95°C for a period
of about 5 to about 8 hours to assist in permitting the fusion or coalescence of the
toner aggregates and to obtain smooth toner particles;
- (x) washing the resulting toner slurry;
- (xi) isolating the toner particles and drying in an oven;
- (i) a toner process wherein there is selected a latex, a magnetite dispersion that
contains water and an anionic surfactant, a colorant dispersion which contains carbon
black water and an anionic surfactant, and a wax dispersion comprised of submicron
wax particles of from about 0.1 to about 0.9 micron in diameter by volume, and which
wax is dispersed in an anionic surfactant;
- (ii) wherein the latex is comprised of two latex emulsions, a noncrosslinked latex
and a crosslinked latex, and wherein each of the latexes contain resin particles,
water and an anionic surfactant;
- (iii) adding to the resulting mixture with a pH of about 2 to about 3 a coagulant,
and which coagulant is a polymetal halide, a cationic surfactant, or mixtures thereof
to primarily enable flocculation of the resin latexes, the magnetite, the colorant,
and the wax;
- (iv) heating the resulting mixture below about the glass transition temperature (Tg)
of the latex resin to form toner sized aggregates;
- (v) adding to the formed toner aggregates a latex comprised of noncrosslinked resin
suspended in an aqueous phase containing an ionic surfactant and water;
- (vi) adding to the resulting mixture of (v) an aqueous solution of an organic complexing
compound or agent, such as EDTA, dissolved in sodium hydroxide to thereby change the
pH from an initial about 2 to about 2.9 to a pH of from about 7 to about 8;
- (vii) heating the resulting aggregate suspension of (vi) to above the Tg of the latex
resin of (i);
- (viii) optionally retaining the mixture temperature at from about 70°C to about 95°C
optionally for a period of about 25 to about 60 minutes, followed by a pH reduction
with an acid to arrive at a pH of about 4 to about 5 to assist in permitting the fusion
or coalescence of the toner aggregates;
- (ix) further retaining the mixture temperature at from about 85°C to about 95°C for
an optional period of about 4 to about 10 hours to assist in permitting the fusion
or coalescence of the toner aggregates to obtain smooth particles; and
- (x) washing the resulting toner slurry, and isolating the toner; a process wherein
the colorant dispersion contains an anionic surfactant; a process wherein the colorant
is carbon black, and wherein the carbon black dispersion comprises carbon black particles
dispersed in water and an anionic surfactant, and wherein the colorant is present
in an amount of from about 4 to about 10 weight percent; a process wherein the amount
of acicular magnetite selected is from about 20 to about 40 percent by weight of toner,
and the coagulant is comprised of a first coagulant of a polymetal halide present
in an amount of about 0.02 to about 2 percent by weight of toner, and a further second
cationic surfactant coagulant present in an amount of about 0.1 to about 5 percent
by weight of toner; a process wherein the amount of acicular magnetite selected is
from about 23 to about 35 percent by weight of toner, and the amount of coagulant,
which coagulant is a polymetal halide, is selected in an amount of about 0.05 to about
0.15 percent by weight of toner; a process wherein the acicular magnetite utilized
exhibits a coercivity of from about 250 to about 700 Oe; a process wherein the acicular
magnetite possesses a coercivity of from about 250 to about 500 Oe, a remanent magnetization
(Br) of about 23 to about 39 emu/gram, and a saturation magnetization (Bm) of about
70 to about 90 emu/gram; a process wherein the toner exhibits a magnetic signal of
about 90 to about 150 percent of the nominal where the nominal is a signal strength
of about 100 percent; a process wherein the toner possesses a minimum fix temperature
(MFT) of about 170°C to about 195°C; a process wherein the toner hot offset temperature
(HOT) is from about 210°C to about 250°C; a process wherein the magnetite dispersion
is obtained by ball milling, attrition, polytroning or media milling with an anionic
surfactant resulting in magnetite particles suspended in water containing the anionic
surfactant; a process wherein the colorant is carbon black, and the amount of the
carbon black dispersion is from about 3 to about 10 percent by weight of toner; a
process wherein the crosslinked resin contains resin particles of from about 0.15
to about 0.4 micron in volume average diameter, and a second latex contains a resin
free of crosslinking; a process wherein the magnetite size is from about 0.6 micron
to about 0.1 micron in average volume diameter, and the colorant is carbon black,
and the carbon black is from about 0.01 to about 0.2 micron in average volume diameter;
a process wherein the acid is nitric, sulfuric, hydrochloric, citric or acetic acid,
and the coagulant is comprised of a first coagulant of a polyaluminum chloride and
a second coagulant of a cationic surfactant; a process wherein the noncrosslinked
latex is selected in an amount of from about 10 to about 40 percent by weight of the
initial latex (i) to form a shell thereover on the formed aggregates, and which shell
is of an optional thickness of about 0.1 to about 1 micron, and wherein the coagulant
is a polymetal halide; a process wherein the added latex contains the same resin as
the initial latex containing the noncrosslinked resin of (i), or wherein the added
latex contains a dissimilar resin than that of the initial latex; a process wherein
the temperature at which toner sized aggregates are formed controls the size of the
aggregates, and wherein the final toner size is from about 3 to about 25 microns in
volume average diameter; a process wherein the aggregation (iv) temperature is from
about 40°C to about 65°C, and wherein the coalescence or fusion temperature of (vii)
and (viii) is from about 80°C to about 95°C, and wherein the coagulant is a polyaluminum
halide; a process wherein the time of coalescence or fusion is from about 4 to about
12 hours, and wherein the MICR toner resulting possesses a smooth morphology; a process
wherein the latex contains a resin, which resin is free or substantially free of crosslinking,
and which resin is selected from the group comprised of poly(styrene-alkyl acrylate),
poly(styrene-1,3-diene), poly(styrene-alkyl methacrylate), poly(alkyl methacrylate-alkyl
acrylate), poly(alkyl methacrylate-aryl acrylate), poly(aryl methacrylate-alkyl acrylate),
poly(alkyl methacrylate), poly(styrene-alkyl acrylate-acrylonitrile), poly(styrene-1,3-diene-acrylonitrile),
poly(alkyl acrylate-acrylonitrile), poly(styrene-butadiene), poly(methylstyrene-butadiene),
poly(methyl methacrylate-butadiene), poly(ethyl methacrylate-butadiene), poly(propyl
methacrylate-butadiene), poly(butyl methacrylate-butadiene), poly(methyl acrylate-butadiene),
poly(ethyl acrylate-butadiene), poly(propyl acrylate-butadiene), poly(butyl acrylate-butadiene),
poly(styrene-isoprene), poly(methylstyrene-isoprene), poly(methyl methacrylate-isoprene),
poly(ethyl methacrylate-isoprene), poly(propyl methacrylate-isoprene), poly(butyl
methacrylate-isoprene), poly(methyl acrylate-isoprene), poly(ethyl acrylate-isoprene),
poly(propyl acrylate-isoprene), poly(butyl acrylate-isoprene); poly(styrene-propyl
acrylate), poly(styrene-butyl acrylate), poly(styrene-butadiene-acrylonitrile), and
poly(styrene-butyl acrylate-acrylononitrile); a process wherein the resin contains
a carboxylic acid selected from the group comprised of acrylic acid, methacrylic acid,
itaconic acid, beta carboxy ethyl acrylate, fumaric acid, maleic acid, cinnamic acid,
and the like, and wherein the carboxylic acid is selected in an amount of from about
0.1 to about 10 weight percent; a process wherein a crosslinking component monomer
is added to the resin, and wherein the monomer is optionally selected in an amount
of from about 0.5 to about 15 percent by weight; a process wherein the latex contains
a resin or polymer selected from the group consisting of poly(styrene-alkyl acrylate),
poly(styrene-1,3-diene), poly(styrene-alkyl methacrylate), poly(styrene-alkyl acrylate-acrylic
acid), poly(styrene-1,3-diene-acrylic acid), poly(styrene-alkyl methacrylate-acrylic
acid), poly(alkyl methacrylate-alkyl acrylate), poly(alkyl methacrylate-aryl acrylate),
poly(aryl methacrylate-alkyl acrylate), poly(alkyl methacrylate-acrylic acid), poly(styrene-alkyl
acrylate-acrylonitrile-acrylic acid), poly(styrene-1,3-diene-acrylonitrile-acrylic
acid), and poly(alkyl acrylate-acrylonitrile-acrylic acid), and wherein the coagulant
is a polymetal halide; a toner process comprising the heating of a magnetite dispersion,
a colorant dispersion, a latex emulsion free of crosslinking, a crosslinked latex
emulsion, and a coagulant of a polymetal halide, and wherein the mixture is aggregated
by heating below the latex uncrosslinked resin glass transition temperature; a process
wherein there is optionally further included a second coagulant of a cationic surfactant
coagulant; a process wherein the coagulant is polymetal halide of a polyaluminum chloride,
or a polyaluminum sulfate selected in an amount of about 0.05 to about 0.3 pph by
weight of toner, and there is optionally added to the mixture a second cationic surfactant
coagulant of an alkylbenzyl dimethyl ammonium chloride in an amount, for example,
of from about 0.1 to about 2 by weight of toner; a process wherein the wax dispersion
contains a polyethylene wax, water, and an anionic surfactant, and wherein the wax
is selected in an amount of from about 5 to about 20 weight percent; a process wherein
the wax dispersion contains a polypropylene wax, water, and an anionic surfactant,
and wherein the wax is selected in an amount of from about 5 to about 20 weight percent;
a process wherein the optional second coagulant is selected from the group comprised
of alkylbenzyl dimethyl ammonium chloride, dialkyl benzenealkyl ammonium chloride,
lauryl trimethyl ammonium chloride, alkylbenzyl methyl ammonium chloride, alkyl benzyl
dimethyl ammonium bromide, benzalkonium chloride, and cetyl pyridinium bromide present
in an amount of about 0.1 to about 5 percent by weight of toner; a toner composition
process wherein the acicular magnetite possesses a coercivity of about 250 to about
700 Oe, a particle size of about 0.6 micron in length x 0.1 micron in diameter, a
coercivity of from about 250 to about 500 Oe, a remanent magnetization (Br) of about
23 to 39 emu/gram, and a saturation magnetization (Bm) of about 70 to about 90 emu/gram;
a coercivity of about 345 Oe, a remanent magnetization (Br) of about 35 emu/gram,
and a saturation magnetization (Bm) of about 85 emu/gram; a coercivity of about 370
Oe, a remanent magnetization (Br) of about 33 emu/gram, and a saturation magnetization
(Bm) of about 83 emu/gram; a magnetite with a coercivity of about 270 Oe, a remanent
magnetization (Br) of about 20 emu/gram, and a saturation magnetization (Bm) of about
79 emu/gram; a coercivity of from about 250 to about 400 Oe, a remanent magnetization
(Br) of about 23 to about 55 emu/gram, and a saturation magnetization (Bm) of about
70 to about 90 emu/gram; and wherein the acicular magnetite is present in the toner
in an amount of from about 10 to about 40 weight percent; a process wherein the acicular
magnetite possesses a coercivity of about 250 to about 700 Oe, a particle size of
about 0.6 micron in length x 0.1 micron in diameter, a magnetite with a coercivity
of from about 250 to about 500 Oe, a remanent magnetization (Br) of about 23 to about
39 emu/gram, and a saturation magnetization (Bm) of about 70 to about 90 emu/gram;
and wherein the wax is a polyethylene, a polypropylene, or mixtures thereof; a process
wherein the crosslinked resin is selected in an amount of from about 1 to about 40
weight percent; a process wherein the crosslinked resin is selected in an amount of
from about 2 to about 25 weight percent; a process wherein the crosslinked resin is
poly(styrene butylacrylate, beta carboxy ethyl acrylate divinyl benzene); a process
wherein the resin free from crosslinking possesses a molecular weight Mw of about 20,000 to about 500,000, and an onset glass transition (Tg) temperature
of from about 45°C to about 70°C; a process wherein the crosslinked latex resin possesses
a molecular weight Mw of about 100,000 to about 1,000,000, and an onset glass transition (Tg) temperature
of about 48°C to about 58°C; a process wherein the crosslinked resin latex is selected
in an amount of from about 2 to about 15 weight percent, the latex free of a crosslinked
resin is selected in an amount of from about 40 to about 65 weight percent, the magnetite
is selected in an amount of from about 20 to about 35 weight percent, the wax is selected
in an amount of from about 5 to about 15 weight percent, and wherein the total thereof
is about 100 percent based on the toner; a process wherein the resulting toner possesses
a shape factor of from about 110 to about 148; a process wherein the colorant dispersion
contains colorant and an anionic surfactant; a process wherein colorant dispersion
is comprised of carbon black particles dispersed in water and an anionic surfactant;
a process wherein the amount of acicular magnetite selected is from about 15 to about
40 percent by weight of toner, and the coagulant is a polymetal halide present in
an amount of about 0.02 to about 0.4 percent by weight of toner; a process where the
coagulant is a cationic surfactant present in the amount of about 0.1 to about 2 percent
by weight of toner; a process wherein the coagulant is comprised of a mixture of a
polymetal halide and a cationic surfactant; a process wherein the amount of acicular
magnetite selected is from about 23 to about 32 percent by weight of toner, and the
amount of coagulant, which coagulant is a polymetal halide, is present in an amount
of about 0.05 to about 0.13 percent by weight of toner, and the optional cationic
surfactant coagulant is present in an amount of about 0.15 to about 1.5 percent by
weight of toner; a process wherein the noncrosslinked resin or polymer has a glass
transition temperature (Tg) of about 45°C to about 70°C; a process wherein the noncrosslinked
resin possesses a weight average molecular weight of about 20,000 to about 90,000;
a process wherein the crosslinked latex contains a polymer, wherein the crosslinking
percentage or value is, for example, from about 20 to about 75 percent, or about 25
to about 55 of poly(styrene-alkyl acrylate), poly(styrene-1,3-diene), poly(styrene-alkyl
methacrylate), poly(alkyl methacrylate-alkyl acrylate), poly(alkyl methacrylate-aryl
acrylate), poly(aryl methacrylate-alkyl acrylate), poly(alkyl methacrylate), poly(styrene-alkyl
acrylate-acrylonitrile), poly(styrene-1,3-diene-acrylonitrile), poly(alkyl acrylate-acrylonitrile),
poly(styrene-butadiene), poly(methylstyrene-butadiene), poly(methyl methacrylate-butadiene),
poly(ethyl methacrylate-butadiene), poly(propyl methacrylate-butadiene), poly(butyl
methacrylate-butadiene), poly(methyl acrylate-butadiene), poly(ethyl acrylate-butadiene),
poly(propyl acrylate-butadiene), poly(butyl acrylate-butadiene), poly(styrene-isoprene),
poly(methylstyrene-isoprene), poly(methyl methacrylate-isoprene), poly(ethyl methacrylate-isoprene),
poly(propyl methacrylate-isoprene), poly(butyl methacrylate-isoprene), poly(methyl
acrylate-isoprene), poly(ethyl acrylate-isoprene), poly(propyl acrylate-isoprene),
poly(butyl acrylate-isoprene); poly(styrene-propyl acrylate), poly(styrene-butyl acrylate),
poly(styrene-butadiene-acrylonitrile), and poly(styrene-butyl acrylate-acrylononitrile),
and wherein the polymer in addition contains a crosslinking component, such as divinyl
benzene (DVB), to enable the crosslinked resin or polymer, and wherein the crosslinking
component can be selected in an amount of from about 0.1 to about 15 weight percent;
a process wherein the polymer, in addition to DVB, can contain a carboxylic acid,
and which carboxylic acid is, for example, selected from the group comprised of acrylic
acid, methacrylic acid, itaconic acid, beta carboxy ethyl acrylate; and the like,
and wherein the carboxylic acid is present in an amount of from about 0.5 to about
10 weight percent; a process comprising the heating of a magnetite dispersion, a colorant
dispersion, a latex emulsion, a crosslinked polymer, wherein the crosslinking is,
for example, from about 30 to about 75 percent, and coagulants, wherein one of the
coagulants is a polyaluminum chloride, or bromide, and the optional second coagulant
is a cationic surfactant, such as an alkylbenzyl dimethyl ammonium chloride, and wherein
the mixture is aggregated by heating below the latex uncrosslinked resin glass transition
temperature, followed by the addition of the complexing compound dissolved in a base,
and thereafter, heating above the latex uncrosslinked resin glass transition temperature;
a process wherein the aggregate mixture pH value is about 7 to about 7.7 obtained
by the addition of the complexing compound dissolved in a base like sodium hydroxide;
a process wherein the acicular magnetite, which can be comprised of 21 percent FeO
and 79 percent Fe2O3 is selected from the group consisting of B2510, B2540, B2550, HDM-S 7111 with a coercivity
of from about 250 to about 500 Oe and a remanent magnetization (Br) of about 23 to
about 39 emu/gram, and a saturation magnetization (Bm) of about 75 to about 90 emu/gram,
all available from Magnox; MR-BL with a coercivity of about 340 Oe, a remanent magnetization
(Br) of about 35 emu/gram, and a saturation magnetization (Bm) of about 85 emu/gram,
all available from Titan Kogyo and Columbia Chemicals; MTA-740 with a coercivity of
about 370 Oe, a remanent magnetization (Br) of about 35 emu/gram, and a saturation
magnetization (Bm) of about 83 emu/gram, and all available from Toda Kogyo Inc.; AC
5151M with a coercivity of about 270 Oe, a remanent magnetization (Br) of 20 emu/gram,
and a saturation magnetization (Bm) of 79 emu/gram, available from Bayer Corporation;
MO4232, MO4431 with a coercivity of from about 250 to about 400 Oe, a remanent magnetization
(Br) of about 23 to about 60 emu/gram, and a saturation magnetization (Bm) of about
70 to about 90 emu/gram, available from Elementis Inc.; wherein the toner exhibits
a magnetic signal of from about 125 to about 150 percent of the nominal signal where
nominal signal refers to the signal strength of 100 percent, and wherein the acicular
magnetite selected is present in the toner in an amount, for example, of from about
10 to about 35 weight percent, and more specifically, in an amount of about 22 to
about 32 weight percent by weight of toner; a toner process as illustrated herein
wherein the amount of resin free of crosslinking is from about 40 to about 65 weight
percent, the amount of crosslinked resin is from about 2 to about 15 weight percent;
the amount of magnetite is from about 20 to about 35 weight percent; the colorant
amount is from about 4 to about 10 weight percent; and the wax amount is from about
5 to about 15 weight percent; and the total of the components is 100 percent; a process
for preparing a chemical toner wherein the blending and aggregation are performed
at a pH of about 2 to about 3 or about 2 to about 2.8, while the coalescence is initially
conducted at a pH of about 7 to about 8 followed by a reduction in pH to about 5.5
to about 6.5, and followed by further heating for a period of hours, for example,
about 6 to about 12 hours; and a process for preparing a MICR toner composition by
emulsion aggregation, which toner possesses a smooth shape and feel, and contains
from about 20 to about 40 weight percent of an acicular magnetite, wax, crosslinked
resin, and colorant, and with a toner particle size distribution of about 1.20 to
about 1.26, and which toner provides a MICR signal of about 90 to about 140 percent
and a bulk remanence of about 26 emu/gram wherein the remanence can be measured on
a tapped powder magnetite sample in a cell of 1 centimeter X 1 centimeter X about
4 centimeters. The sample is magnetized between two magnetic pole faces with a saturating
magnetic field of 2,000 Gauss, such that the induced magnetic field is perpendicular
to one of the 1 X 4 centimeter faces of the cell. The sample is removed from the saturating
magnetic field, and the remanence is measured perpendicular to the above 1 centimeter
wide face using a Hall-Effect device or a gaussmeter, such as the F.W. Bell, Inc.
Model 615 gaussmeter.
[0036] The resin or polymer selected for the process of the present invention can be prepared
by a number of known methods such as, for example, emulsion polymerization, including
semicontinuous emulsion polymerization methods, and the monomers utilized in such
processes can be selected from, for example, styrene, acrylates, methacrylates, butadiene,
isoprene, acrylonitrile; monomers comprised of an A and a B monomer wherein from about
75 to about 95 percent of A and from about 5 to about 25 percent of B is selected,
wherein A can be, for example, styrene, and B can be, for example, an acrylate, methacrylate,
butadiene, isoprene, or an acrylonitrile; and optionally, acid or basic olefinic monomers,
such as acrylic acid, methacrylic acid, beta carboxy ethyl acrylate, acrylamide, methacrylamide,
quaternary ammonium halide of dialkyl or trialkyl acrylamides or methacrylamide, vinylpyridine,
vinylpyrrolidone, vinyl-N-methylpyridinium chloride and the like. The presence of
acid or basic groups in the monomer or polymer resin is optional, and such groups
can be present in various amounts of from about 0.1 to about 10 percent by weight
of the polymer resin. Chain transfer agents, such as dodecanethiol or carbon tetrabromide,
can also be selected when preparing resin particles by emulsion polymerization. Other
processes of obtaining resin particles of, for example, from about 0.01 micron to
about 1 micron in diameter can be selected like polymer microsuspension process, such
as those illustrated in
U.S. Patent 3,674,736, the disclosure of which is totally incorporated herein by reference, polymer solution
microsuspension process, such as disclosed in U.S. Patent
5,290,654, the disclosure of which is totally incorporated herein by reference, mechanical
grinding process, or other known processes; and toner processes wherein the resin
possesses a crosslinking percentage of from about 1 to about 50 or from about 1.5
to about 30.
[0037] Colorants include dyes, pigments, and mixtures thereof, colorant examples being illustrated
in a number of the copending applications referenced herein, and more specifically,
which colorants include known colorants like black, cyan, red, blue, magenta, green,
brown, yellow, mixtures thereof, and the like.
[0038] Various known colorants, such as pigments, selected for the processes of the present
invention and present in the toner in an effective amount of, for example, from about
1 to about 25 percent by weight of toner, and more specifically, in an amount of from
about 3 to about 10 percent by weight include, for example, carbon black like REGAL
330
®; REGAL 660
®; phthalocyanine Pigment Blue 15, Pigment Blue 15.1, Pigment Blue 15.3, Pigment Green
7, Pigment Green 36, Pigment Orange 5, Pigment Orange 13, Pigment Orange 16, Pigment
Orange 36, Pigment Red 122, Pigment Red 53.1, Pigment Red 48.1, Pigment Red 48.2,
Pigment Red 49.1, Pigment Red 49.2, Pigment Red 22, Pigment Red 185, Pigment Red 188,
Pigment Red 210, Pigment Red 238, Pigment Red 170, Pigment Red 23, Pigment Red 81.2,
Pigment Red 81.3, Pigment Red 57, Pigment Red 17, Pigment Red 169, Pigment Violet
19, Pigment Violet 23, Pigment Violet 3, Pigment Violet 27, Pigment Yellow 65, Pigment
Yellow 1, Pigment Yellow 83, Pigment Yellow 17, Pigment Yellow 12, Pigment Yellow
14, Pigment Yellow 97, Pigment Yellow 74, Pigment Yellow 3, Pigment Yellow 75, available
from Sun Chemicals, PIGMENT VIOLET 1™, PIGMENT RED 48™, LEMON CHROME YELLOW DCC 1026™,
E.D. TOLUIDINE RED™ and BON RED C™ available from Dominion Color Corporation, Ltd.,
Toronto, Ontario, NOVAPERM YELLOW FGL™, HOSTAPERM PINK E™ available from Hoechst,
and CINQUASIA MAGENTA™ available from E.I. DuPont de Nemours and Company, and the
like. Generally, colored pigments that can be selected are cyan, magenta, or yellow
pigments, and mixtures thereof. Examples of magentas that may be selected 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 cyans
that may be selected include copper tetra(octadecyl sulfonamido) phthalocyanine, x-copper
phthalocyanine pigment identified in the Color Index as CI 74160, CI Pigment Blue,
and Anthrathrene Blue, identified in the Color Index as CI 69810, Special Blue X-2137,
and the like; while illustrative examples of yellows 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, Yellow 180 and Permanent Yellow
FGL, wherein the colorant is present, for example, in the amount of about 3 to about
15 weight percent of the toner. Organic dye examples include known suitable dyes,
reference the Color Index, and a number of U.S. patents. Organic soluble dye examples,
preferably of a high purity, for the purpose of color gamut are Neopen Yellow 075,
Neopen Yellow 159, Neopen Orange 252, Neopen Red 336, Neopen Red 335, Neopen Red 366,
Neopen Blue 808, Neopen Black X53, Neopen Black X55, wherein the dyes are selected
in various suitable amounts, for example from about 0.5 to about 20 percent by weight,
and more specifically, from about 5 to about 20 weight percent of the toner. Colorants
may include pigment, dye, mixtures of pigment and dyes, mixtures of pigments, mixtures
of dyes, and the like.
[0039] Crosslinked resin examples with crosslinking values as illustrated herein, and yet
more specifically, of, for example, from about 25 to about 80, and more specifically,
from about 30 to about 65 percent, and which resins are selected in various amounts,
such as from about 1 to about 20, and more specifically, from about 5 to about 10
weight percent based on the weight percentages of the remaining toner components,
include the resins illustrated herein, which resins are crosslinked by known crosslinking
compounds, such as divinyl benzene. Specific crosslinked resin examples are poly(styrene
divinyl benzene beta CEA), poly(styrene butyl acrylate divinyl benzene beta CEA),
poly(styrene divinyl benzene acrylic acid), poly(styrene butyl acrylate divinyl benzene
acrylic acid), and the like.
[0040] Examples of anionic surfactants that can be selected for the processes illustrated
herein include, for example, sodium dodecylsulfate (SDS), sodium dodecylbenzene sulfonate,
sodium dodecylnaphthalene sulfate, dialkyl benzenealkyl, sulfates and sulfonates,
abitic acid, available from Aldrich, NEOGEN RK™, NEOGEN SC™ from Kao, DOWFAX™ obtained
from Dow Chemicals, ABEX™ obtained from Rhodia, and the like. An effective concentration
of the anionic surfactant generally employed is, for example, from about 0.01 to about
10 percent by weight, and preferably from about 0.1 to about 5 percent by weight of
monomers used to prepare the toner polymer resin.
[0041] Examples of nonionic surfactants that can be selected for the processes illustrated
herein and that may be, for example, included in the resin latex dispersion are, for
example, polyvinyl alcohol, polyacrylic acid, methalose, methyl cellulose, ethyl cellulose,
propyl cellulose, hydroxy ethyl cellulose, carboxy methyl cellulose, polyoxyethylene
cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether, polyoxyethylene
octylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate,
polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, dialkylphenoxypoly(ethyleneoxy)
ethanol, available from Rhodia as IGEPAL CA-210
®, IGEPAL CA-520
®, IGEPAL CA-720
®, IGEPAL CO-890
®, IGEPAL CO-720
®, IGEPAL CO-290
®, IGEPAL CA-210
®, ANTAROX 890
® and ANTAROX 897
®, PLURONICS™ obtained from BASF. A suitable concentration of the nonionic surfactant
is, for example, from about 0.01 to about 10 percent by weight, and more specifically,
from about 0.1 to about 5 percent by weight of monomers used to prepare the toner
polymer resin.
[0042] Examples of cationic surfactants, which are usually positively charged, selected
for the toners and processes of the present invention include, for example, alkylbenzyl
dimethyl ammonium chloride dialkyl benzenealkyl ammonium chloride, lauryl trimethyl
ammonium chloride, alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl ammonium
bromide, benzalkonium chloride, cetyl pyridinium bromide, C
12, C
15, C
17 trimethyl ammonium bromides, halide salts of quaternized polyoxyethylalkylamines,
dodecylbenzyl triethyl ammonium chloride, MIRAPOL™ and ALKAQUAT™, available from Alkaril
Chemical Company, Aldrich Chemicals SANIZOL™ (benzalkonium chloride), available from
Kao Chemicals, and the like, and mixtures thereof. A suitable amount of cationic surfactant
can be selected, such as from about 0.2 to about 5 percent by weight of the toner
components.
[0043] Examples of a complexing compound that can be selected are those that are suitable,
such as ethylenediamine tetraacetic acid; diethylenetriamine pentacetic acid; nitrilotriacetic
acid; the corresponding salts of the aforementioned, such as the alkali metal salts
like sodium, potassium, calcium, and the like, and which complexing compound can be
mixed with soap, water, and the like. Also, in embodiments, biodegradable compounds
of the complexing compounds illustrated can also be selected. Specific examples of
organic complexing compounds or agents include ethylene diamine tetraacetic acid (EDTA),
gluconal, sodium gluconate, potassium and sodium citrate, nitrotriacetate (NTA) salt,
GLDA (commercially available L-glutamic acid N,N diacetic acid) humic and fulvic acids,
maltol and ethyl-maltol, peta-acetic and tetraacetic acids; the corresponding salts
of the aforementioned, such as the alkali metal salts like sodium, potassium, calcium,
and the like.
and
[0044] Counterionic coagulants selected for the processes illustrated herein can be comprised
of organic, or inorganic components, and the like. For example, in embodiments the
ionic surfactant of the resin latex dispersion can be an anionic surfactant, and the
counterionic coagulant can be a polymetal halide or a polymetal disulfo compound (PASS).
Coagulants that can be included in amounts of, for example, from about 0.05 to about
10 weight percent include polymetal halides, polymetal disulfo compounds, divalent
or multivalent salts optionally in combination with cationic surfactants, and the
like. Inorganic cationic coagulants include, for example, polyaluminum chloride (PAC),
polyaluminum sulfates (PASS), aluminum sulfate, zinc sulfate, or magnesium sulfate.
[0045] The coagulant is in embodiments present in an aqueous medium in an amount of from,
for example, about 0.05 to about 10 percent by weight, and more specifically, in an
amount of from about 0.075 to about 2 percent by weight. The coagulant may also contain
minor amounts of other components, such as for example nitric acid. The coagulant
is usually added slowly while continuously subjecting the mixture resulting to high
shear, for example, by stirring with a blade at about 3,000 to about 10,000 rpm, and
preferably about 5,000 rpm, for about 1 to about 120 minutes. A high shearing device,
for example an intense homogenization device, such as the in-line IKA SD-41, may be
used to ensure that the coagulant is homogeneous and uniformly dispersed.
[0046] Examples of waxes include those as illustrated herein, such as those of the aforementioned
copending applications, polypropylenes and polyethylenes commercially available from
Allied Chemical and Petrolite Corporation, wax emulsions available from Michaelman
Inc. and the Daniels Products Company, EPOLENE N-15™ commercially available from Eastman
Chemical Products, Inc., VISCOL 550-P™ , a low weight average molecular weight polypropylene
available from Sanyo Kasei K.K., and similar materials. The commercially available
polyethylenes selected possess, it is believed, a molecular weight M
w of from about 500 to about 15,000, while the commercially available polypropylenes
are believed to have a molecular weight of from about 3,000 to about 7,000. Examples
of functionalized waxes are amines, amides, for example AQUA SUPERSLIP 6550™, SUPERSLIP
6530™ available from Micro Powder Inc., fluorinated waxes, for example POLYFLUO 190™,
POLYFLUO 200™, POLYFLUO 523XF™, AQUA POLYFLUO 411™, AQUA POLYSILK 19™, POLYSILK 14™
available from Micro Powder Inc., mixed fluorinated, amide waxes, for example MICROSPERSION
19™ also available from Micro Powder Inc., imides, esters, quaternary amines, carboxylic
acids or acrylic polymer emulsions, for example JONCRYL 74™, 89™, 130™, 537™, and
538™, all available from SC Johnson Wax; chlorinated polypropylenes and polyethylenes
available from Allied Chemical and Petrolite Corporation and SC Johnson Wax. The amounts
of the wax selected in embodiments is, for example, from about 3.5 to about 15 percent
by weight of toner.
[0047] The solids content of the resin latex dispersion is not particularly limited, thus
the solids content may be from, for example, about 10 to about 90 percent. With regard
to the colorants, such as carbon black, in some instances they are available in the
wet cake or concentrated form containing water, and can be easily dispersed utilizing
a homogenizer or simply by stirring or ball milling, attrition, or media milling.
In other instances, pigments are available only in a dry form whereby dispersion in
water is effected by microfluidizing using, for example, a M-110 microfluidizer or
an ultimizer, and passing the pigment dispersion from about 1 to about 10 times through
a chamber by sonication, such as using a Branson 700 sonicator, with a homogenizer,
ball milling, attrition, or media milling with the optional addition of dispersing
agents such as the aforementioned ionic or nonionic surfactants.
[0048] During coalescence, the pH is increased, for example, from about 2 to about 3 to
about 7 to about 8; from about 2 to about 2.8 to about 7 to about 7.5 by the addition
of a suitable pH agent of, for example, sodium hydroxide to provide for the stabilization
of the aggregated particles and to prevent/minimize the toner size growth and loss
of GSD during further heating, for example, raising the temperature about 10°C to
about 50°C above the resin Tg. Also, the complexing compound provides for a coating
thereof on the magnetite particles thereby lowering the Pzc of the magnetite such
that during the coalescence where the pH of the mixture reduced to below about 5 and
preferably about 4.5, the fusion of the aggregates can be accomplished by using an
acid. Examples of pH reducing agents include, for example, nitric acid, citric acid,
sulfuric acid or hydrochloric acid, and the like.
[0049] In embodiments, the toner particles formed by processes illustrated herein possess,
for example, an average volume diameter of from about 0.5 to about 25, and more specifically,
from about 1 to about 10 microns, and narrow GSD characteristics of, for example,
from about 1.05 to about 1.25, or from about 1.15 to about 1.25 as measured by a Coulter
Counter. The toner particles also possess an excellent shape factor, for example,
of 135 or less wherein the shape factor refers, for example, to the measure of toner
smoothness and toner roundness where a shape factor of about 100 is considered spherical
and smooth without any surface protrusions, while a shape factor of about 150 is considered
to be rough in surface morphology and the shape is like a potato.
[0050] The toner particles illustrated herein may also include known charge additives in
effective amounts of, for example, from about 0.1 to about 5 weight percent, such
as alkyl pyridinium halides, bisulfates, the charge control additives of
U.S. Patents 3,944,493;
4,007,293;
4,079,014;
4,394,430 and
4,560,635, the disclosures of which are totally incorporated herein by reference, and the like.
Surface additives that can be added to the toner compositions after washing or drying
include, for example, metal salts, metal salts of fatty acids, colloidal silica, metal
oxides, mixtures thereof and the like, which additives are usually present in an amount
of from about 0.1 to about 2 weight percent, reference
U.S. Patents 3,590,000;
3,720,617;
3,655,374 and
3,983,045, the disclosures of which are totally incorporated herein by reference. Specific
additives include zinc stearate and AEROSIL R972
® available from Degussa Chemical, and each present in an amount of from about 0.1
to about 2 percen, which can be added during the aggregation process or blended into
the formed toner product, calcium stearate and the like.
[0051] Developer compositions can be prepared by mixing the toners obtained with the process
of the present invention with known carrier particles, including coated carriers,
such as steel, ferrites, and the like, reference
U.S. Patents 4,937,166 and
4,935,326, the disclosures of which are totally incorporated herein by reference, for example
from about 2 percent toner concentration to about 8 percent toner concentration.
[0052] The following Examples are provided. Parts and percentages are by weight unless otherwise
indicated, and temperatures are in degrees Centigrade.
EXAMPLES
Preparation of Noncrosslinked Latex A:
[0053] A latex emulsion (i) comprised of polymer particles generated from the emulsion polymerization
of styrene, butyl acrylate and beta carboxy ethyl acrylate (Beta CEA) was prepared
as follows. A surfactant solution of 434 grams of DOWFAX 2A1™ (anionic emulsifier
-55 percent active ingredients) and 387 kilograms of deionized water was prepared
by mixing these components for 10 minutes in a stainless steel holding tank. The holding
tank was then purged with nitrogen for 5 minutes before transferring the mixture into
a reactor. The reactor was then continuously purged with nitrogen while being stirred
at 100 RPM. The reactor was then heated to 80°C.
[0054] Separately, 6.11 kilograms of ammonium persulfate initiator were dissolved in 30.2
kilograms of deionized water. Also, separately a monomer emulsion A was prepared in
the following manner. 315.7 Kilograms of styrene, 91.66 kilograms of butyl acrylate,
12.21 kilograms of beta-CEA, 7.3 kilograms of 1-dodecanethiol, 1.42 kilograms of decanediol
diacrylate (ADOD), 8.24 kilograms of DOWFAX™ (anionic surfactant), and 193 kilograms
of deionized water were mixed to form an emulsion. Five percent of the above emulsion
was then slowly fed into the reactor containing the aqueous surfactant phase at 80°C
to form seeds wherein "seeds" refer, for example, to the initial emulsion latex added
to the reactor prior to the addition of the initiator solution while being purged
with nitrogen. The above initiator solution was then slowly charged into the reactor
forming about 5 to about 12 nanometers of latex "seed" particles. After 10 minutes,
the remainder of the emulsion was continuously fed using metering pumps.
[0055] After the above monomer emulsion was charged into the main reactor, the temperature
was maintained at 80°C for an additional 2 hours to complete the reaction. The reactor
contents were then cooled down to about 25°C. The resulting isolated product was comprised
of 40 weight percent of submicron, 0.5 micron diameter resin particles of styrene/butylacrylate/beta
CEA suspended in an aqueous phase containing the above surfactant. The molecular properties
resulting for the resin latex were M
w (weight average molecular weight) of 35,000, M
n of 10,600 as measured by a Gel Permeation Chromatograph, and a midpoint Tg of 55.8°C,
as measured by a Differential Scanning Calorimeter where the midpoint Tg is the halfway
point between the onset and the offset Tg of the polymer.
Preparation of the Crosslinked Latex B (50 nanometers):
[0056] A crosslinked latex emulsion comprised of polymer particles generated from the emulsion
polymerization of styrene, butyl acrylate and beta carboxy ethyl acrylate (p) CEA
was prepared as follows. A surfactant solution of 4.08 kilograms of NEOGEN™ RK (anionic
emulsifier) and 78.73 kilograms of deionized water was prepared by mixing these components
for 10 minutes in a stainless steel holding tank. The holding tank was then purged
with nitrogen for 5 minutes before transferring the resulting mixture into the above
reactor. The reactor was then continuously purged with nitrogen while the contents
were being stirred at 100 RPM. The reactor was then heated up to 76°C, and held there
for a period of 1 hour.
[0057] Separately, 1.24 kilograms of ammonium persulfate initiator were dissolved in 13.12
kilograms of deionized water.
[0058] Also separately, monomer emulsion was prepared in the following manner. 47.39 Kilograms
of styrene, 25.52 kilograms of butyl acrylate, 2.19 kilograms of β-CEA, 0.729 kilogram
of divinyl benzene (DVB) crosslinking agent, 1.75 kilograms of NEOGEN™ RK (anionic
surfactant), and 145.8 kilograms of deionized water were mixed to form an emulsion.
One (1) percent of the emulsion was then slowly fed into the reactor while the reactor
was being purged with nitrogen containing the aqueous surfactant phase at 76°C to
form "seeds". The initiator solution was then slowly charged into the reactor and
after 40 minutes the remainder of the emulsion was continuously fed in using metering
pumps over a period of 3 hours.
[0059] Once all the monomer emulsion was charged into the above main reactor, the temperature
was held at 76°C for an additional 4 hours to complete the reaction. Cooling was then
accomplished and the reactor temperature was reduced to 35°C. The product was collected
into a holding tank. After drying, the resin latex onset Tg was 53.5°C. The resulting
latex was comprised of 25 percent crosslinked resin, 72.5 percent water and 2.5 percent
anionic surfactant. The resin had a ratio of 65:35:3 pph:1 pph of styrene:butyl acrylate:β-CEA:DVB.
The mean particle size of the gel latex was 50 nanometers as measured on disc centrifuge,
and the resin in the latex possessed a crosslinking value of 25 percent as measured
by known gravimetric methods.
Wax and Pigment Dispersions:
[0060] The aqueous wax dispersion utilized in the following Examples was generated using
waxes available from Baker-Petrolite (1) P725 polyethylene wax with a low molecular
weight M
w of 725, and a melting point of 104°C, or (2) P850 wax with a low molecular weight
of 850 and a melting point of 107°C and NEOGEN RK™ as an anionic surfactant/dispersant.
The wax particle diameter size was determined to be approximately 200 nanometers,
and the wax slurry was a solid loading of 30 percent (weight percent throughout).
[0061] The pigment dispersion, obtained from Sun Chemicals, was an aqueous dispersion containing
carbon black (REGAL 330
®), an anionic surfactant, 2 percent, and 79 percent water.
EXAMPLE I
Toner Preparation - PAC (0.1 pph) - with 50 Nanometer Gel, 1 pph of EDTA:
[0062] 79 Grams of MAGNOX B2550™ acicular magnetite composed of 21 percent FeO and 79 percent
Fe
2O
3 having a particle size of about 0.6 micron X 0.1 micron was added to 600 grams of
water containing 1.3 grams of a 20 percent aqueous anionic surfactant (NEOGEN RK™)
to which 85 grams of an 18 percent carbon black REGAL 330
® solution were added. The resultant mixture was then polytroned or homogenized at
a speed of 5,000 rpm, for 3 minutes, to provide a pigment dispersion. To the resulting
pigment dispersion was added 90 grams of a dispersion of submicron polyethylene P
850 wax particles (30 percent solids) followed by the addition of 320 grams of the
above prepared anionic latex A comprised of submicron latex particles (40 percent
solids) of styrene/butylacrylate/beta CEA, and 64 grams of the cross linked latex
B of styrene/butylacrylate/divinyl benzene beta CEA (25.5 percent solids) while polytroned
at a speed of 5,000 rpm for a period of 5 minutes 300 grams of water were added to
reduce the viscosity of the resulting blend to which then was added an aqueous PAC
(polyaluminum chloride) solution comprised of 3.1 grams of a 10 percent solids placed
in 25 grams of 0.3M nitric acid.
[0063] The resulting blend was then heated to a temperature of 50°C while stirring for a
period of 100 minutes to obtain a particle size of 5.3 micron with a GSD of 1.20.
140 Grams of the above prepared noncrosslinked latex (Latex A) were then added to
the aggregate mixture, and followed by stirring at 50°C for 130 minutes to provide
a particle size of 5.9 microns and a GSD of 1.20. The aggregate mixture was then stabilized
from further growth by introducing 10.5 grams of a basic mixture of EDTA powder dissolved
in sodium hydroxide and containing 30 percent solids thereby changing the pH of the
mixture from a value of 2.6 to 4.5, followed by adding 4 percent of sodium hydroxide
to arrive at a pH of about 7. The mixture was then heated to 93°C during which the
pH decreased to 6.5. After 10 minutes at 93°C the particle size measure was 6.2 with
a GSD of 1.20. After 60 minutes the pH was reduced to 4.7. The particle size measure
was 6.4 with a GSD of 1.22. The mixture was then further heated for a period of 600
minutes at a pH of 4.7 and the particle size obtained was 6.4 microns with a GSD of
1.20. The resultant mixture was cooled and the toner obtained was washed 4 times with
water and dried on the freeze dryer. The resulting toner was comprised of 25 percent
magnetite, 57.1 percent noncrosslinked resin, 5 percent crosslinked resin, 4.4 percent
carbon black, and 8.5 percent wax. The charge of the toner was 19.8 microC/g as measured
against the FC076 carrier, similar to the control or the comparative toner. The development
of the resulting toner as a function of development voltage under various throughput
conditions illustrated that the toner performance was stable to aging under various
throughputs of printing. The target MICR signal of 120 percent of the nominal (nominal
being 100 percent) was achieved at a development voltage of 250. The toner was then
evaluated in a Xerox Corporation DC 265 engine and toner development as a function
of voltage did not change at different throughputs conditions, for example the development
at time zero, and that after 1,000 prints including under zero throughput conditions
(xerographic stress case) at a given voltage indicated little toner aging.
[0064] The above toner when fused in a Xerox Corporation DC 265 xerographic engine possessed
a MFT (melt fusing temperature) of 187°C and a HOT offset temperature greater than
about 210°C, (for example, about an estimated 214°C) the optimum temperature that
could be measured by the temperature detector used. The shape factor of the toner
was 125 where a SF of 100 is considered very smooth and spherical in shape; a SF of
145 is considered irregular in shape with a rough morphology; and a SF of 125 is considered
a potato shape with a smooth surface.
Toner Preparation - PAC (0.1 pph) - with 50 nanometer gel; 1.25 pph of EDTA
[0065] 79 Grams of MAGNOX B2550™ acicular magnetite composed of 21 percent FeO and 79 percent
Fe
2O
3 having a particle size of about 0.6 micron X 0.1 micron was added to 600 grams of
water containing 1.3 grams of 20 percent aqueous anionic surfactant (NEOGEN RK™) to
which 85 grams of an 18 percent carbon black REGAL 330
® solution were added. The resultant mixture was then polytroned or homogenized at
a speed of 5,000 rpm for 3 minutes to provide a pigment dispersion. To the resulting
pigment dispersion were added 90 grams of a dispersion of submicron polyethylene P
850 wax particles 30 percent solids followed by the addition of 320 grams of the anionic
Latex A comprised of submicron latex particles (40 percent solids) of styrene/butylacrylate/beta
CEA, and 64 grams of the crosslinked Latex B of styrene/butylacrylate/divinyl benzene
beta CEA (25.5 percent solids) while polytroned at a speed of 5,000 rpm for a period
of 5 minutes 300 grams of water were added to reduce the viscosity of the resulting
blend to which was then added an aqueous PAC solution comprised 3.1 grams of 10 percent
solids placed in 25 grams of 0.3M nitric acid.
[0066] The resulting blend was then heated to a temperature of 50°C while stirring for a
period of 100 minutes to obtain a particle size of 5.5 microns with a GSD of 1.21.
140 Grams of the above noncrosslinked latex (Latex A) were then added to the aggregate
mixture and stirred at 50°C for 120 minutes to provide a particle size of 6 microns
and a GSD of 1.20. The aggregate mixture was then stabilized from further growth by
introducing 13.4 grams of a basic mixture of EDTA powder dissolved in sodium hydroxide
containing 30 percent solids to change the pH of the mixture from value of 2.6 to
4.9, followed by adding 4 percent sodium hydroxide resulting in a pH of about 70.
The mixture was then heated to 93°C during which the pH decreased to 6.5. After 10
minutes at 93°C, the particle size measured was 6.1 with a GSD of 1.20. After 60 minutes,
the pH was reduced to 4.6 by adding 4 percent nitric acid. The particle size measured
was 6.3 with a GSD of 1.21. The mixture was then further heated for a period of 600
minutes at a pH of 4.6 and the particle size obtained was 6.4 microns with a GSD of
1.20. The resultant mixture was cooled and the toner obtained was washed 4 times with
water and dried on the freeze dryer. The resulting toner was comprised of 25 percent
magnetite, 57.1 percent noncrosslinked resin, 5 percent crosslinked resin, 4.4 percent
carbon black, and 8.5 percent wax. The shape factor of this toner was 126. The charge
of the toner was -17 microC/g measured against a carrier comprised of a ferrite carrier
coated with a polymer mixture of butylmethylmethacrylate/methylmethylacrylate or preferably
the carrier of the Xerox Corporation Docutech 2240 machine.
Toner Preparation- PAC (0.1 pph)- with 50 Nanometers Gel; 1.50 pph of EDTA:
[0067] 79 Grams of MAGNOX B2550™ acicular magnetite composed of 21 percent FeO and 79 percent
Fe
2O
3 having a particle size of about 0.6 micron X 0.1 micron were added to 600 grams of
water containing 1.3 grams of 20 percent aqueous anionic surfactant (NEOGEN RK™) to
which 85 grams of an 18 percent carbon black REGAL 330
® solution were added. The resultant mixture was then polytroned or homogenized at
a speed of 5,000 rpm for 3 minutes to provide a pigment dispersion. To the resulting
pigment dispersion were added 90 grams of a dispersion of submicron polyethylene P
850 wax particles (30 percent solids) followed by the addition of 320 grams of the
anionic Latex A comprised of submicron latex particles (40 percent solids) of styrene/
butylacrylate/beta CEA, and 64 grams of the crosslinked Latex B of styrene/butylacrylate/divinyl
benzene beta CEA (25.5 percent solids) while polytroned at a speed of 5,000 rpm for
a period of 5 minutes. 300 Grams of water were added to reduce the viscosity of the
resulting blend to which was then added an aqueous PAC solution comprised of 3.1 grams
of 10 percent solids placed in 25 grams of 0.3M nitric acid.
[0068] The resulting blend was then heated to a temperature of 50°C while stirring for a
period of 100 minutes to obtain a particle size of 5.4 microns with a GSD of 1.19.
140 Grams of the above noncrosslinked latex (Latex A) were then added to the aggregate
mixture and stirred at 50°C for 120 minutes to provide a particle size of 5.8 microns
and a GSD of 1.20. The aggregate mixture was then stabilized from further growth by
introducing 16 grams of a basic mixture of EDTA powder dissolved in sodium hydroxide
containing 30 percent solids to change the pH of the mixture from a value of 2.6 to
4.5, followed by adding 4 percent sodium hydroxide resulting in a pH of about 7. The
mixture was then heated to 93°C during which the pH decreased to 6.3. After 10 minutes
at 93°C the particle size measure was 6.3 with a GSD of 1.20. After 60 minutes, the
pH was reduced to 4.5 by adding 4 percent nitric acid. The particle size measured
was 6.3 with a GSD of 1.21. The mixture was then further heated for a period of 600
minutes at a pH of 4.5 and the particle size obtained was 6.4 microns with a GSD of
1.20. The resultant mixture was cooled and the toner obtained was washed 4 times with
water and dried on the freeze dryer. The resulting toner was comprised of 25 percent
magnetite, 57.1 percent noncrosslinked resin, 5 percent crosslinked resin, 4.4 percent
carbon black, and 8.5 percent wax. The shape factor for this toner was 124. The dry
toner charge triboelectric was -16.4 microC/g as measured against a carrier comprised
of a ferrite carrier coated with a polymer mixture of butylmethylmethacrylate/methylmethylacrylate
or preferably the carrier of the Xerox Corporation Docutech 2240 machine.
COMPARATIVE EXAMPLE
[0069] A comparative toner (T 2239) was prepared in a similar manner as the above Examples
and where sodium hydroxide was used as a stabilizer instead of EDTA resulting in a
particle size of 6.8 microns with a GSD of 1.23. The pH of the mixture was allowed
to drift to below 6.8 during the ramping of the temperature to 93°C. The coalesce
pH was reduced to a pH of 5.8 in stages over a period of 2 hours and the mixture resulting
heated for a period of 10 hours. The resulting particle size was 7.6 microns with
a GSD of 1.27. The charge of this toner against the carrier was 15.1 microC/g.
[0070] The claims, as originally presented and as they may be amended, encompass variations,
alternatives, modifications, improvements, equivalents, and substantial equivalents
of the embodiments and teachings disclosed herein, including those that are presently
unforeseen or unappreciated, and that, for example, may arise from applicants/patentees
and others.