BR112014015643B1 - CHEMICALLY PREPARED TONER COMPOSITION - Google Patents

Abstract

chemically prepared toner formula including a borax coupling agent a chemically prepared toner composition in accordance with an exemplary embodiment including a core including a first polymer binder, a dye and a release agent; a shell that is formed around the core and includes a second polymer binder; and a borax coupling agent between the core and shell.

Description

Cross-references to related orders

[001] This patent application is related to United States Patent Application Serial No. 13/339,565 (Attorney's Precedent No. P7-US1), filed on December 29, 2011, entitled "Process for Preparing Toner including to Borax Coupling Agent", and assigned to the assignee of the present application.

Justification 1. Disclosure Field

[002] The present invention relates generally to toner, chemically prepared for use in electrophotography, and more particularly to chemically preparing a toner including a borax coupling agent.

2. Description of Related Art

[003] Toners for use in electrophotographic printers include two main types, mechanically ground toners and chemically prepared (CPT) toners. Chemically prepared toners have significant advantages over mechanically milled toners, including better print quality, higher toner transfer efficiency, and lower torque properties for various electrophotographic printer components such as a developer roller, a fusing belt, and a charge. The particle size distribution of CPT is typically narrower than the particle size distribution of mechanically milled toners. The size and shape of CPTs are also easier to control than mechanically milled toners.

[004] There are several known types of CPT including suspension polymerization toner (SPT), emulsion aggregation toner (EAT) / latex aggregation toner (LAT), toner made from a dispersion of preformed polymer in solvent ( DPPT) and "chemically milled" toner. Although emulsion aggregation toner requires a more complex process than other CPTs, the resulting toner has a relatively narrow size distribution. Emulsion aggregation toners can also be manufactured with a smaller particle size, allowing for improved print resolution. The emulsion aggregation process also allows for better control of the shape and structure of toner particles which allows them to be tailored to meet desired cleaning, fit and transfer properties. The shape of the toner particles can be optimized to ensure proper and efficient cleaning of toner from various components of the electrophotographic printer, such as the developer roller, charge roller and adjuster blades, in order to prevent filming or deposition. unwanted toner on these components.

[005] In a typical process for the preparation of EAT, the emulsion aggregation is carried out in an aqueous system resulting in good control of both the size and shape of the toner particles. Toner components typically include a polymer binder, one or more dyes, and a release agent. A styrene-acrylic polymer binder is often used as the latex binder in the emulsion aggregation process. However, the use of a styrene-acrylic copolymer latex binder requires a compromise between the melting properties of the toner and its transport and storage properties. The fusing properties of a toner include the fusing window. The fusing window is the temperature range at which fusing is performed satisfactorily, with no incomplete fusing and no transfer of toner to the heating element, which may be a roller, belt, or other toner contact member during fusing. . Thus, below the lower limit of the fusing window the toner is not completely melted and above the upper limit of the fusing window the toner flows to the fixing member where it deteriorates subsequent sheets being fixed. It is preferable that the lower end of the fusing window be as low as possible to reduce the required fusing temperature in the electrophotographic printer to improve printer safety and conserve energy. However, the toner must also be able to survive the extreme temperature and humidity associated with storage and transport without skewing or blocking, which can result in print failures. As a result, the decrease in the bottom edge of the fuser window may not be so low that the toner may melt while storing or shipping a toner cartridge that contains the toner.

[006] Toners formed from polyester binder resins typically have better mechanical properties than toners formed from a styrene-acrylic copolymer binder of similar melt viscosity characteristics. This makes them more durable and resistant to film formation from printer components. Polyester toners also have better compatibility with color pigments, resulting in a wider color gamut. Until recently, polyester binder resins were often used in the preparation of mechanically ground toners, but rarely in chemically prepared toners. Polyester binder resins are manufactured using condensation polymerization. This method is very time consuming due to the involvement of long polymerization cycles and therefore limits the use of polyester binder resins to polyester polymers that have low or moderate molecular weights, which limits the melting properties of the toner. Furthermore, polyester binder resins are more difficult to disperse in an aqueous system than, due to their polar nature, pH sensitivity and gel content, thus limiting their applicability in the emulsion aggregation process.

[007] However, with the advancement of toner manufacturing technology, it became possible to obtain stable emulsions formed using polyester binder resins by first dissolving them in an organic solvent such as methyl ethyl ketone (MEK) , methylene chloride, ethyl acetate, or tetrahydrofuran (THF), and then perform a phase inversion process in which water is slowly added to the organic solvent. The organic solvent is then evaporated to allow the polyester binder resins to form stable emulsions. US Patent No. 7,939,236 entitled "Chemically Prepared Toner and Process Therefor", which is assigned to the assignee of the present application and incorporated herein by reference in its entirety, describes a similar process for obtaining a stable emulsion using an organic solvent. . These advances allowed the use of polyester binder resins to form emulsion aggregation toner. For example, US Patent No. 7,923,191 entitled "Polyester Resin Produced by Emulsion Aggregation", and US Patent Application Serial No. 12/206,402 entitled "Emulsion Aggregation Toner Formulation", which is assigned to the assignee of the present application. and incorporated by reference herein in their entirety, describe processes for preparing emulsion aggregation toner using polyester binder resins.

[008] These techniques provide the ability to produce an emulsion aggregation toner, which has excellent fusibility; however, issues related to surface migration of low molecular weight resins, waxes and dyes persist. Migration of these ingredients to the surface of the toner particle weakens the toner's melting and transport/storage properties and increases the occurrence of film formation on printer components. Therefore, it will be appreciated that an emulsion aggregation toner formulation and process that reduces the migration of low molecular weight resins, waxes and dyes to the surface of the toner particles is desired. It is also desirable to minimize the total number of fine toner particles, which contribute to film formation on printer components.

SUMMARY

[009] A chemically prepared toner composition according to an exemplary embodiment includes a core that includes a first polymer binder, a dye, and a release agent; a shell that is formed around the core and includes a second polymer binder; and a borax coupling agent between the core and the shell.

BRIEF DESCRIPTION OF THE DRAWINGS

[010] The characteristics and advantages mentioned above and others of the various modalities, and the way of achieving them, will be more evident and better understood by referring to the attached drawings.

[011] Figure 1 is an image of a conventional emulsion aggregation toner particle taken with a scanning electron microscope.

[012] Figure 2 is an image of emulsion aggregation toner particles that include a borax binding agent between the toner core and shell layers according to an exemplary embodiment.

[013] Figure 3 is a graph depicting the pH adjustment window for an emulsion aggregation toner that includes a borax binding agent between the toner core and shell layers in accordance with an exemplary embodiment compared to a conventional emulsion aggregation toner, a toner that includes a zinc sulfate coupling agent, and a toner that includes an aluminum sulfate coupling agent.

DETAILED DESCRIPTION

[014] The following description and drawings illustrate embodiments sufficiently to enable those skilled in the art to practice the present invention. It is to be understood that this disclosure is not limited to the details of construction and arrangement of the components shown in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. For example, other modalities may incorporate structural, chronological, process, and other modifications. Merely symbolic examples of possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. The portions and features of some modalities may be included or substituted for those of others. The scope of application encompasses the appended claims and all available equivalents. The following description is therefore not to be taken in a limited sense and the scope of the present invention is defined by the appended claims. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be considered as limiting. The use of the term "including", "comprising" or "having" and variations thereof is intended herein to encompass the items listed below and their equivalents, as well as additional items.

[015] The present invention relates to a chemically prepared toner that contains a borax coupling agent between the core and shell layers of a toner and an associated emulsion aggregation method of preparation. Toner can be used in an electrophotographic printer, such as a printer, copier, multi-function device or an all-in-one device. Toner can be supplied in a toner cartridge, which is fed to the electrophotographic printer. Example methods of forming toner using conventional emulsion aggregation techniques can be found in US Patent Nos. 6,531,254 and 6,531,256, which are incorporated herein by reference in their entirety.

[016] In the present emulsion aggregation process, toner particles are delivered through chemical methods as opposed to physical methods such as spraying. Generally, the toner includes one or more polymer binders, a release agent, a dye, a borax coupling agent, and one or more optional additives, such as a charge control agent (CCA). An emulsion of a polymer binder is formed in water, optionally, with an organic solvent, with an inorganic base, such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, or an organic amine compound. A stabilizing agent having an anionic functional group (A-), for example an anionic surfactant or an anionic polymeric dispersant may also be included. It will be appreciated that a cationic (C+) functional group, for example a cationic surfactant or a cationic polymeric dispersant, can be substituted if desired. Polymer latex is used at two points during the toner forming process. A first portion of the polymeric latex is used to form the core of the resulting toner particle and a second portion of the polymeric latex is used to form a shell around the toner core. The first and second polymer latex parts can be formed separately or together. Where the portions of the polymeric latex that form the toner core and toner shell are formed separately, either the same or different polymer binders may be used. The ratio of the amount of polymeric binder in the toner core to the amount of toner in the shell is from about 20:80 (by weight) to about 80:20 (by weight), including all values and increments therebetween. , such as between about 50:50 (by weight) and about 80:20 (by weight), depending on the particular resin used.

[017] The dye, release agent, and optional CCA are dispersed separately in their own aqueous media or in an aqueous mixture, as desired, in the presence of a stabilizing agent having a similar functionality (and ionic charge) as the stabilizing agent used in polymeric latex. The polymeric latex that forms the toner core, the release agent dispersion, the dye dispersion and the optional CCA dispersion are then mixed and agitated to ensure a homogeneous composition. As used herein, the term dispersion refers to a system in which particles are dispersed in a continuous phase of a different composition (or state), and may include an emulsion. Acid is then added to lower the pH and cause flocculation. Flocculation refers to the process by which destabilized particles conglomerate (due, for example, to the presence of available counter-ions) into relatively large aggregates. In this case, flocculation includes the formation of a gel, where the resin, dye, release agent and CCA form an aggregate mixture, typically from particles 1-2 microns (μm) in size. Unless otherwise indicated, reference to particle size refers to the largest cross-sectional dimension of the particle. The aggregated toner particles can then be heated to a temperature that is less than or about (e.g., ±5°C) the glass transition temperature (Tg) of the polymer latex to induce aggregate growth of the aggregate particles. Once the aggregate particles reach the desired size for the toner core, the borax coupling agent is added so that it forms on the surface of the toner core. After the addition of the borax coupling agent, the polymeric latex forming the toner shell is added. This polymeric latex aggregates around the toner core to form the toner shell. Once the aggregate particles reach the desired toner size, the base can be added to raise the pH and reionize the anionic stabilizing agent to prevent particle growth or additional anionic stabilizing agents can be added. The temperature is then raised above the glass transition temperature (Tg) of the polymer latex to fuse the particles together in each agglomerate. This temperature is maintained until the particles reach the desired circularity. The toner particles are then washed and dried.

[018] The toner particles produced may have an average particle size of between about 3 μm and about 20 μm (volume average particle size), including all values and increments therebetween, such as between about 4 μm and about 15 μm or, more particularly, between about 5 μm and about 7 μm The toner particles produced can have an average degree of circularity between about 0.90 and about 1.00, including all values and increments therebetween, such as about 0.93 to about 0.98. The average degree of roundness and average particle size can be determined by a Sysmex Particle Flow Image Analyzer (eg FPIA-3000) available from Malvern Instruments.

[019] The different components for the emulsion aggregation process to prepare the above-referenced toner will be described below. It should be noted that the various characteristics of the indicated components can be adjusted to facilitate the step of aggregation and formation of toner particles of desired size and geometry. Therefore, it can be appreciated that by controlling the indicated characteristics, one can first form relatively stable dispersions where aggregation can proceed further with relatively easy control of the final particle size of toner for use in an electrophotographic printer or cartridge. of printer. polymer binders

[020] As mentioned above, the toners in the present invention include one or more polymeric binders. The polymer resin and terms are used interchangeably herein as there is no difference between the two techniques. In one embodiment, the polymeric binder includes polyesters. The polyester binder may include a semicrystalline polyester binder, a crystalline polyester binder, or an amorphous polyester binder. Alternatively, the polyester binder may include a polyester copolymer resin binder. For example, the polyester binder may include a styrene/acrylic polyester copolymer graft. The polyester binder can be formed using monomeric acids such as terephthalic acid, trimellitic anhydride, dodecyl succinic anhydride and fumaric acid. Furthermore, the polyester binder can be formed from alcohol monomers such as ethoxylated and propoxylated bisphenol A. Examples of polyester resins include, but are not limited to, T100, TF-104, NE-1582, NE-701, NE-2141, NE-1569, Binder C, FPESL-2, W-85N, TL-17, TPESL-10, TPESL-11 polyester resins from Kao Corporation, Bunka Sumida-ku, Tokyo, Japan, or mixtures thereof.

[021] In other embodiments, the polymer binder includes a thermoplastic-type polymer, such as styrene and/or substituted styrene polymer, such as a homopolymer (e.g., polystyrene) and/or copolymer (e.g., styrene copolymer -butadiene and/or a styrene-acrylic copolymer, a styrene-butyl methacrylate copolymer and/or polymers made from styrene-butyl acrylate and other acrylic monomers such as hydroxyacrylates or hydroxyl methacrylates); polyvinyl acetate, polyalkenes, poly(vinyl chloride), polyurethanes, polyamides, silicones, epoxy resins, or phenolic resins.

[022] As discussed above, in some embodiments, the toner core may be formed from one polymer binder (or blend) and the toner shell formed from another. Furthermore, the ratio of the amount of polymeric binder in the toner core to the amount of toner in the toner shell can be from about 20:80 (by weight) to about 80:20 (by weight) or more specifically. between about 50:50 (by weight) and about 80:20 (by weight), including all values and increments therebetween. The total polymeric binder can be provided in the range of about 70% to about 95% by weight of the final toner formulation, including all values and increments therein. Borax coupling agent

[023] The binding agent used here is borax (also known as sodium borate, sodium tetraborate, or disodium tetraborate). As used herein, the term coupling agent refers to a chemical compound having the cross-linking ability to link two or more components together. Typically, coupling agents are capable of multivalent binding. Borax differs from commonly used permanent coupling agents such as polyvalent metal ions (eg aluminum and zinc) in that its binding is reversible. In the electrophotographic process, toner is preferred to have a low fusing temperature to conserve energy and a low viscosity in the molten ("soft") state to allow high speed printing at low fusing temperatures. However, in order to maintain the stability of the toner during shipping and storage and to prevent film formation on printer components, the toner is preferred to be "harder" at temperatures below the fusing temperature. Borax provides cross-linking through hydrogen bonds between the hydroxyl groups and the functional groups of the molecules to be linked. The hydrogen bond is temperature and pressure sensitive and is not a stable, permanent bond. For example, when the temperature is increased to a certain degree or tension is applied to the polymer, the bond will be partially or completely broken causing the polymer to "flow" or tear. The reversibility of the bonds formed by the borax coupling agent is particularly useful in toner as it allows for a "soft" toner at the melting temperature, but a "hard" toner at the storage temperature.

[024] It has also been observed that borax surprisingly causes fine particles to accumulate into larger particles. As a result, borax is particularly suitable as a binding agent between the toner core and shell layers because it builds up the toner core components to the core particles before the shell is added, thus reducing residual fines. on toner. This, in turn, reduces the amount of acid needed in the agglomeration phase and narrows the toner particle size distribution.

[025] Borax also serves as a good buffer in the toner formation reaction, as a result of the equilibrium formed by boric acid and its conjugate base. The presence of borax makes the reaction more resistant to pH changes and widens the pH adjustment window of the reaction compared to a conventional emulsion aggregation process. The pH adjustment window is crucial for industrial scale process to control particle size. With a wider window, the process is easier to control on an industrial scale.

[026] The amount of the borax coupling agent used here can be varied. The borax coupling agent may be supplied at from about 0.1% to about 5.0% by weight of the total polymer binder in the toner, including all amounts and increments therein, such as between about from 0.1% to about 1.0% or from about 0.1% to about 0.5%. If too much coupling agent is used, their bond cannot be completely broken at high melting temperature. On the other hand, if too little coupling agent is used, it may fail to provide the desired binding and buffering effects. Dye

[027] Dyes are compositions that impart color or other visual effects to toner and may include carbon black, dyes (which may be soluble in a given medium and capable of precipitation), pigments (which may be insoluble in a given medium). ) or a combination of the two. The dye dispersion can be prepared by mixing the pigment in water with a dispersant. Alternatively, a self-dispersing dye can be used, thereby allowing the dispersing agent to be omitted. The dye may be present in the dispersion at a level of from about 5% to about 20%, by weight, including all values and increments therebetween. For example, the dye may be present in the dispersion at a level of from about 10% to about 15% by weight.

[028] The dye dispersion can contain particles of a size from about 50 nanometers (nm) to about 500 nm and all values and increments in between. In addition, the dye dispersion may have a pigment weight percent divided by dispersant weight percent (P/D ratio) from about 1:1 to about 8:1, including all values and increments therebetween. , such as about 2:1 to about 5:1. The dye may be present in less than or equal to about 15% by weight of the final toner formulation, including all amounts and increments therein. Release Agent

[029] The release agent may include any compound that facilitates the release of toner from a component of an electrophotographic printer (eg, release from a roller surface). For example, the release agent may include polyelefin wax, ester wax, polyester wax, polyethylene wax, fatty acid metal salts, fatty acid esters, partially saponified fatty acid esters, higher fatty acid esters, alcohols higher, paraffin waxes, carnauba wax, amide waxes and polyhydric alcohol esters.

[030] The release agent may thus include a polymer based on a low molecular weight hydrocarbon (e.g. Mn < 10,000), which has a melting point of less than about 140 °C, including all values and increments between about 50°C and about 140°C. For example, the release agent may have a melting point of about 60°C to about 135°C, or between about 65°C to about 100°C, etc. The release agent may be present in the dispersion in an amount from about 5% to about 35%, by weight, including all amounts and increments therein. For example, the release agent may be present in the dispersion in an amount from about 10% to about 18% by weight. The release agent dispersion may also contain particles of a size from about 50 nm to about 1 μm, including all values and increments therebetween. In addition, the release agent dispersion can be further characterized as having a weight percent release agent divided by weight percent dispersant (RA/D ratio) of from about 1:1 to about 30:1. For example, the RA/D ratio can be from about 3:1 to about 8:1. The release agent can be provided in the range of about 2% to about 20% by weight of the final toner formulation, including all amounts and increments therein. Surfactant / Dispersant

[031] A surface-active agent, a polymeric dispersant or a combination thereof can be used. The polymeric dispersant can generally comprise three components, namely, a hydrophilic component, a hydrophobic component and a colloidal protective component. The term hydrophobic refers to a chemical structure of a relatively nonpolar type that tends to self-associate in the presence of water. The hydrophobic component of the polymeric dispersant may include electron-rich or long-chain hydrocarbon functional groups. Such functional groups are known to exhibit strong interaction and/or adsorption properties with respect to the surface of the particles, such as the dye and polyester resin binder of the polyester resin emulsion. Hydrophilic functionality refers to relatively polar functionality (eg, an anionic group), which may then tend to associate with water molecules. The colloidal protective component includes a water-soluble group with no ionic function. The colloidal protective component of the polymeric dispersant provides additional stability to the hydrophilic component in an aqueous system. The use of the colloidal protective component substantially reduces the amount of ionic monomer segment or hydrophilic component in the polymeric dispersant. In addition, the colloidal protective component stabilizes the polymeric dispersant in low acid media. The colloidal protective component generally includes polyethylene glycol (PEG) groups. The dispersant employed herein may include the dispersants described in US Patent No. 6,991,884 and US Patent No. 5,714,538, which are incorporated herein by reference in their entirety.

[032] The surfactant, as used herein, may be a conventional surfactant known in the art for the dispersion of self-dispersing dyes and unused release agents for the preparation of toner formulations for electrophotography. Commercial surfactants such as the AKYPO series of AKYPO carboxylic acids from Kao Corporation, Bunka Sumida-ku, Tokyo, Japan can be used. For example, alkyl ether carboxylates and alkyl ether sulfates, preferably lauryl ether carboxylates and lauryl ether sulfates, respectively, can be used. A suitable anionic surfactant is AKYPO RLM-100 available from Kao Corporation, Bunka Sumida-ku, Tokyo, Japan, which is laureth-11 carboxylic acid, thus providing the anionic carboxylate functionality. Other anionic surfactants contemplated herein include alkyl phosphates, alkyl sulfonates and alkyl benzene sulfonates. Sulfonic acid containing polymers or surfactants may also be used. Optional Additives

[033] The toner formulation of the present disclosure may also include one or more conventional charge control agents, which may optionally be used to prepare the toner formulation. A charge control agent can be understood as a compound that assists in the production and stability of a tribocharge in the toner. The charge control agent also helps to prevent deterioration of the charge properties of the toner formulation. The load controlling agent can be prepared as a dispersion in a manner similar to the dyes and release agent dispersions discussed above.

[034] [The toner formulation may include one or more additives, such as acids and/or bases, emulsifiers, UV absorbers, fluorescent additives, pearlescent additives, plasticizers and combinations thereof. These additives may be desired to improve the properties of a printed image using the present toner formulation. For example, UV absorbers can be included to increase resistance to degradation by UV light, preventing gradual fading of the image after subsequent exposures to ultraviolet radiation. As suitable examples of the UV absorbers include, but are not limited to, benzophenone, benzotriazole, acetanilide, triazine and derivatives thereof. Commercial plasticizers, which are known in the art, can also be used to adjust the coalescing temperature of the toner formulation.

[035] The following examples are provided to further illustrate the teachings of the present disclosure, and not to limit the scope of the present disclosure. EXAMPLES Example of magenta pigment dispersion

[036] About 10g of AKYPO RLM-100 polyoxyethylene(10) carboxylic acid lauryl ether from Kao Corporation, Bunka Sumida-ku, Tokyo, Japan was combined with about 350g of deionized water and the pH adjusted to ~ 7-9 using sodium hydroxide. About 10g of Solsperse 27000 from Lubrizol Advanced Materials, Cleveland, Ohio, USA, was added and the dispersant and water mixture was mixed with an electric stirrer, followed by the relatively slow addition of 100g of Red Pigment 122. Once the pigment was thoroughly wetted and dispersed, the mixture was added to a horizontal media mill to reduce particle size. The solution was processed in the mill medium until the particle size was about 200 nm. The final pigment dispersion was adjusted to contain about 20% to about 25% solids by weight. Cyan pigment dispersion example

[037] About 10g of AKYPO RLM-100 polyoxyethylene(10) carboxylic acid lauryl ether from Kao Corporation, Bunka Sumida-ku, Tokyo, Japan was combined with about 350g of deionized water and the pH adjusted to ~7 -9 using sodium hydroxide. About 10g of Solsperse 27000 from Lubrizol Advanced Materials, Cleveland, Ohio, USA, was added and the mixture of dispersants and water was mixed with an electric stirrer, followed by the relatively slow addition of 100g of 15:3 blue pigment. Once the pigment was completely wetted and dispersed, the mixture was added to a horizontal media mill to reduce particle size. The solution was processed in the mill medium until the particle size was about 200 nm. The final pigment dispersion was adjusted to contain about 20% to about 25% solids by weight. Example of Wax Emulsion

[038] About 12g of AKYPO RLM-100 polyoxyethylene(10) carboxylic acid lauryl ether from Kao Corporation, Bunka Sumida-ku, Tokyo, Japan was combined with about 325g of deionized water and the pH adjusted to ~7- 9 using sodium hydroxide. The mixture was then processed through a microfluidizer and heated to about 90°C. About 60 g of polyethylene wax from Petrolite, Corp., Westlake, Ohio, USA, was slowly added while the temperature was maintained at about 90°C. C for about 15 minutes. The emulsion was then removed from the microfluidizer when the particle size was less than about 300 nm. The solution was then stirred at room temperature. The wax emulsion was defined to contain about 10% to about 18% solids by weight. Example of Polyester A Resin Emulsion

[039] A mixed polyester resin having a peak molecular weight of about 9000, a glass transition temperature (Tg) of about 53°C to about 58°C, a melting temperature (Tm) of about 110 °C, and an acid number of about 15 to about 20 was used. The glass transition temperature is measured by differential scanning calorimetry (DSC), where, in this case, the beginning of the baseline shift (heat capacity) thus indicates that Tg can occur at about 53 °C at about of 58 °C at a heating rate of about 5 per minute. The acid number may be due to the presence of one or more free carboxylic acid (-COOH) functionalities in the polyester. The acid value refers to the mass of potassium hydroxide (KOH) in milligrams that is needed to neutralize one gram of polyester. The acid value is therefore a measure of the amount of carboxylic acid groups in the polyester.

[040] 150 g of the mixed polyester resin was dissolved in 450 g of methyl ethyl ketone (MEK) in a stirred round bottom flask. The dissolved resin was then poured into a beaker. The beaker was placed in an ice bath directly under a homogenizer. The homogenizer was turned on at high shear and 10 g of 10% potassium hydroxide (KOH) solution and 500 g of deionized water were immediately added to the beaker. The homogenizer was run at high shear for about 2-4 minutes, then the homogenized resin solution was placed in a vacuum distillation reactor. The reactor temperature was maintained at about 43 °C and the pressure was maintained between about 74.5KPa (22 inHg) and about 77.9KPa (23 inHg). About 500 mL of additional deionized water was added to the reactor and the temperature was gradually increased to about 70 °C to ensure that substantially all of the MEK was distilled off. Heating to the reactor was then turned off and the mixture was stirred until room temperature was reached. Once the reactor reached room temperature, the vacuum was turned off and the resin solution was removed and placed in storage flasks.

[041] The particle size of the resin emulsion was between about 185 nm and about 235 nm (volume average) as measured by a NANOTRAC Particle Size Analyzer. The pH of the resin solution was between about 6.5 and about 7.0. Example of polyester resin emulsion B

[042] A polyester resin with a peak molecular weight of about 11,000, a glass transition temperature of about 55°C to about 60°C, a melting temperature of about 110°C, and a value acid of about 15 to about 20 was used to form an emulsion using the procedure described in Polyester Resin Example A, except using 8 g of 10% potassium hydroxide (KOH) solution.

[043] The particle size of the resin emulsion was between about 195 nm and about 235 nm (volume average) as measured by the NANOTRAC Particle Size Analyzer. The pH of the Resin Solution was about 6.7 and about 7.2. Example of C polyester resin emulsion

[044] A polyester resin with a peak molecular weight of about 11,000, a glass transition temperature of about 55°C to about 58°C, a melting temperature of about 115°C, and an index acidity of about 8 to about 13 was used to form an emulsion using the procedure described in Polyester Resin Example A, except using 7 g of 10% potassium hydroxide (KOH) solution.

[045] The particle size of the resin emulsion was between about 190 nm and about 240 nm (volume average) as measured by a NANOTRAC Particle Size Analyzer. The pH of the resin solution was between about 7.5 and about 8.2. Toner Formulation Examples Toner Comparative Example I

[046] Comparative Toner Example I was prepared using a conventional emulsion aggregation process and does not include a borax coupling agent. The aggregation of the CPT emulsion used in this example was an acid agglomeration with a reverse pH used to stop the growth of the toner particles. The components were added to a 2.5 liter reactor in the following relative proportions: 88.2 parts (of polyester by weight) of Example A polyester resin emulsion, 6.8 parts (of pigment by weight) of Example of Magenta Pigment Dispersion, and 5 parts (release agent by weight) of Example Wax Emulsion. Deionized water was then added so that the mixture contained about 12.5% solids by weight.

[047] The mixture was heated in the reactor to 30 °C and a circulation circuit was started consisting of a high shear mixer and an acid addition pump. The mixture was sent through the circuit and the high shear mixer was set at 10,000 revolutions per minute (rpm). Acid was slowly added to the high shear mixer to evenly disperse the acid in the toner mix so that there were no low pH pockets. The addition of acid took about 4 minutes, using 306g of a 1% sulfuric acid solution. The circuit flow was then reversed to return the toner mixture to the reactor. The reactor temperature was increased to about 50 °C to grow the particles. The temperature was maintained at about 50 °C until the particles reached the desired size (average size value from about 5 μm to about 6 μm and volume average size from about 6 μm to about 7 μm). Once the particles reached their desired size, 4% NaOH was added to raise the pH to 6.00 to stop the particles from growing. The reaction was held at about 50 °C for about an hour and then the temperature was increased to 91 °C to cause the particles to coalesce. The particles were kept at 91°C, until the particles reached the desired circularity (about 0.97). The toner was then washed and dried.

[048] The dry toner had a volume average particle size of 6.0 μm as measured by a Coulter Multisizer 3 counter analyzer. Fines (< 2 μm) were present at 4.16% (by number) and the toner had a roundness of 0.970, both measured by the SYSMEX FPIA-3000 Particle Characterization Analyzer, manufactured by Malvern Instruments, Ltd., Malvern, Worcestershire UK. The amount of fines in Comparative Example of Toner I was consistent with other emulsion aggregating polyester toners that do not include a borax coupling agent, which had fines between 1% and 7% (by number).

[049] Additional toners were made using the Toner I comparative example formulation and procedure, except the neutralization pH was changed to test the adjustment pH window. The results of these toners are shown in Table 2 below. Toner A example

[050] Example A polyester resin emulsion was divided into two batches, divided 70:30 by weight, to form the core and toner layer, respectively. The total polyester content represented about 87.7% of the total toner solids. Therefore, the first batch contained 61.4% total toner solids and the second batch contained 26.3% total toner solids. Components were added to a 2.5 liter reactor in the following percentages: the first batch of Example Polyester Resin Emulsion A with 61.4 parts (of polyester by weight), 6.8 parts (of pigment by weight) of Example of Magenta Pigment Dispersion, and 5 parts (release agent by weight) of the emulsion wax example. Deionized water was then added so that the mixture contained about 12% to about 15% solids by weight.

[051] The mixture was heated in a reactor to 30 °C and a circulation circuit was started consisting of a high shear mixer and an acid addition pump. The mixture was sent through the circuit and the high shear mixer was set at 10,000 rpm. Acid was slowly added to the high shear mixer to evenly disperse the acid in the toner mix so that there were no low pH pockets. The addition of acid took about 4 minutes with 200 g of 1% sulfuric acid solution. The circuit flow was then reversed to return the toner mixture to the reactor and the reactor temperature was increased to about 40 - 45 °C. Once the particle size of 4.0 μm (number average) was reached, 5% (by weight) of borax solution (30 g of solution containing 1.5 g of borax) was added. The borax content represented about 0.5% by weight of the total toner solids. After the addition of borax, the second batch of Example Polyester Resin Emulsion A was added which contained 26.3 parts (of polyester by weight). The mixture was stirred for about 5 minutes and the pH was monitored. Once the particle size reached 5.5 μm (number average), 4% NaOH was added to raise the pH to about 5.95 to stop particle growth. The reaction temperature was maintained for one hour. Particle size was monitored during this time period. Once particle growth stopped, the temperature was increased to 88 °C to cause the particles to coalesce. This temperature was maintained until the particles reached their desired circularity (about 0.97). The toner was then washed and dried.

[052] The dry toner had an average particle size volume of 6.65 μm and an average particle size number of 5.49 μm. Fines (< 2 μm) were present in 0.11% (by number) and the toner had a roundness of 0.978.

[053] Additional toners were made using the formulation and procedure of Toner Example A, except that the neutralization pH was changed to test the adjustment pH window. The results of these toners are shown in Table 2 below. B toner example

[054] Example Polyester Resin Emulsion A, was divided into two batches, divided 60:40 by weight, to form the core and toner layer, respectively. The total polyester content represented about 87.9% of total toner solids. Therefore, the first batch contained 52.7% total toner solids and the second batch contained 35.2% total toner solids. Components were added to a 2.5 liter reactor in the following percentages: the first batch of Example Polyester Resin Emulsion A with 52.7 parts (of polyester by weight), 6.8 parts (of pigment by weight) of Example of Magenta Pigment Dispersion and 5 parts (of release agent by weight) of the Wax Emulsion Example. Deionized water was then added so that the mixture contained about 12% to about 15% solids by weight.

[055] The mixture was heated in the reactor to 30 °C and a circulation circuit was started consisting of a high shear mixer and an acid addition pump. The mixture was sent through the circuit and the high shear mixer was set at 10,000 rpm. Acid was slowly added to the high shear mixer to evenly disperse the acid in the toner mix so that there were no low pH pockets. The addition of acid took about 4 minutes with 150 g of 1% sulfuric acid solution. The circuit flow was then reversed to return the toner mixture to the reactor and the reactor temperature was increased to about 40 - 45 °C. Once the particle size reached 4.0 μm (number average), 5% borax solution (15 g of solution containing 0.75 g of borax) was added. The borax content represented about 0.3% by weight of the total toner solids. After the addition of borax, the second batch of Example A polyester resin emulsion was added, which contained 35.2 parts (of polyester by weight). The mixture was stirred for about 5 minutes and the pH was monitored. Once the particle size reached 5.5 μm (number average), 4% NaOH was added to raise the pH to about 5.95 to stop particle growth. The reaction temperature was maintained for one hour. Particle size was monitored during this time period. Once particle growth stopped, the temperature was increased to 88 °C to cause the particles to coalesce. This temperature was maintained until the particles reached their desired circularity (about 0.97). The toner was then washed and dried.

[056] The dry toner had an average particle size volume of 6.24 μm and an average particle size number of 5.48 μm. Fines (< 2 μm) were present in 0.09% (by number) and the toner had a roundness of 0.983. C toner example

[057] A combination of Example Polyester Resin Emulsion A and Example Polyester Resin Emulsion C was used in a ratio of 70:30 by weight to form the toner core and shell, respectively. The total polyester content represented about 87.9% total toner solids. Consequently, Polyester Resin Emulsion Example A contained 61.5% total toner solids and Polyester Resin Emulsion Example C contained 26.4% total toner solids. Components were added to a 2.5 liter reactor in the following percentages: Example of Emulsion of Polyester Resin A with 61.5 parts (of polyester by weight), 6.8 parts (of pigment by weight) of the Example of Dispersion of magenta pigment and 5 parts (by weight release agent) of the Wax Emulsion Example. Deionized water was then added so that the mixture contained about 12% to about 15% solids by weight.

[058] The mixture was heated in the reactor to 30 °C and a circulation circuit was started consisting of a high shear mixer and an acid addition pump. The mixture was sent through the circuit and the high shear mixer was set at 10,000 rpm. The acid was slowly added to the high shear mixer to evenly disperse the acid in the toner mixture so that there were no low pH pockets. The addition of acid took about 4 minutes with 200 g of 1% sulfuric acid solution. The circuit flow was then reversed to return the toner mixture to the reactor and the reactor temperature was increased to about 37 - 42 °C. Once the particle size of 4.0 μm (number average) was reached, 5% (by weight) of borax solution (15 g of a solution containing 0.75 g of borax) was added. The borax content represented about 0.25% by weight of the total toner solids. After the addition of borax, polyester resin emulsion Example C was added, which contained 26.4 parts (of polyester by weight). The mixture was stirred for about 5 minutes and the pH was monitored. Once the particle size reached 5.5 μm (number average), 4% NaOH was added to raise the pH to about 6.60 to stop particle growth. The reaction temperature was maintained for one hour. Particle size was monitored during this time period. Once particle growth stopped, the temperature was increased to 88 °C to cause the particles to coalesce. This temperature was maintained until the particles reached their desired circularity (about 0.97). The toner was then washed and dried.

[059] The dry toner had an average particle size volume of 6.40 μm and an average particle size number of 5.18 μm. Fines (< 2 μm) were present in 0.92% (by number) and the toner had a roundness of 0.970. D toner example

[060] A combination of Example A polyester resin emulsion and an ACT-004 polyester resin emulsion available from Toyobo Co., Ltd., Kita-ku, Osaka, Japan was used in a ratio of 70:30, by weight to form the toner core and shell, respectively. The ACT polyester resin had a peak molecular weight of about 11,000, a glass transition temperature of about 57°C to about 61°C, a melting temperature of about 104°C, and an acid value of about 16. The particle size of the emulsion was about 200 nm (volume average). The total polyester content represented about 87.9% of total toner solids. Consequently, the polyester resin emulsion Example A contained 61.5% total toner solids and the polyester emulsion ACT-004 contained 26.4% total toner solids. The components were added to a 2.5 liter reactor in the following percentages: Example of emulsion of polyester resin A with 61.5 parts (of polyester by weight), 6.8 parts (of pigment by weight) of the Dispersion Example of magenta pigment and 5 parts (by weight of release agent) of the wax emulsion Example. Deionized water was then added so that the mixture contained about 12% to about 15% solids by weight.

[061] The mixture was heated in the reactor to 30 °C and a circulation circuit was started consisting of a high shear mixer and an acid addition pump. The mixture was sent through the circuit and the high shear mixer was set at 10,000 rpm. The acid was slowly added to the high shear mixer to evenly disperse the acid in the toner mixture so that there were no low pH pockets. The addition of acid took about 4 minutes with 200 g of 1% sulfuric acid solution. The circuit flow was then reversed to return the toner mixture to the reactor and the reactor temperature was increased to about 35 - 40 °C. Once the particle size of 4.0 μm (number average) was reached, 5% (by weight) of borax solution (15 g of a solution containing 0.75 g of borax) was added. The borax content represented about 0.25% by weight of the total toner solids. After the addition of borax, the ACT-004 polyester resin emulsion was added, which contained 26.4 parts (of polyester by weight). The mixture was stirred for about 5 minutes and the pH was monitored. Once the particle size reached 5.5 μm (number average), 4% NaOH was added to raise the pH to about 6.20 to stop particle growth. The reaction temperature was maintained for one hour. Particle size was monitored during this time period. Once particle growth stopped, the temperature was increased to 88 °C to cause the particles to coalesce. This temperature was maintained until the particles reached their desired circularity (about 0.97). The toner was then washed and dried.

[062] The dry toner had an average particle size volume of 6.18 μm and an average particle size number of 5.28 μm. Fines (< 2 μm) were present in 0.42% (by number) and the toner had a roundness of 0.973. Example of E toner

[063] Example Polyester Resin Emulsion B was split into two batches, split 70:30 by weight, to form the toner core and shell, respectively. The total polyester content represented about 87.9% of total toner solids. Therefore, the first batch contained 61.5% total toner solids and the second batch contained 26.4% total toner solids. The components were added to a 2.5 liter reactor in the following percentages: The first batch of Polyester Resin Emulsion Example B with 61.5 parts (of polyester by weight), 6.8 parts (of pigment by weight) of the Magenta Dispersion Pigment Example, and 5 parts (of release agent by weight) of the Wax Emulsion Example. Deionized water was then added so that the mixture contained about 12% to about 15% solids by weight.

[064] The mixture was heated in the reactor to 30 °C and a circulation circuit was started consisting of a high shear mixer and an acid addition pump. The mixture was sent through the circuit and the high shear mixer was set at 10,000 rpm. The acid was slowly added to the high shear mixer to evenly disperse the acid in the toner mixture so that there were no low pH pockets. The addition of acid took about 4 minutes with 200 g of 1% sulfuric acid solution. The circuit flow was then reversed to return the toner mixture to the reactor and the reactor temperature was increased to about 40 - 45 °C. Once the particle size reached 5.0 µm (number average), 5% (by weight) of borax solution (15 g of solution containing 0.75 g of borax) was added. The borax content represented about 0.25% by weight of the total toner solids. After the addition of borax, the second batch of example polyester resin B emulsion was added, which contained 26.4 parts (of polyester by weight). The mixture was stirred for about 5 minutes and the pH was monitored. Once the particle size reached 5.5 μm (number average), 4% NaOH was added to raise the pH to about 7.10 to stop particle growth. The reaction temperature was maintained for one hour. Particle size was monitored during this time period. Once particle growth stopped, the temperature was increased to 88 °C to cause the particles to coalesce. This temperature was maintained until the particles reached their desired circularity (about 0.97). The toner was then washed and dried.

[065] The dry toner had an average volume average particle size of 7.24 μm and a number average particle size of 5.86 μm. Fines (< 2 μm) were present in 1.76% (by number) and the toner had a circularity of 0.974.

[066] It can therefore be seen that the emulsion aggregation process used to prepare Examples of toners A through E, which included a borax coupling agent between the core and shell layers of the toner particles, reduced significantly The percentage of fine particles is significant compared to the conventional emulsion aggregation process used to prepare Comparative Toner Example I. In addition, toner Examples A through E each have a comparable average particle size and circularity with respect to Example Toner I comparison as desired. TEST RESULTS Surface Migration

[067] Figure 1 shows an image of a conventional emulsion aggregation toner 10 particle prepared in accordance with Comparative Example I taken with a scanning electron microscope (SEM). Figure 2 shows an image of an emulsion aggregation toner particle 20 prepared in accordance with Example A, which includes a borax coupling agent between the toner core and shell layers. As illustrated, the toner particle 20 has a smoother and more uniform surface than the conventional emulsion aggregation toner particle 10. The smooth, uniform surface of the 20 toner particles reduces filming on the developer roller and improves the toner's fusing performance at higher temperatures. In contrast, toner particles 10 have significantly more dye, release agent and low molecular weight resin particles 12 that have migrated to their surface. As discussed above, borax surprisingly causes these particles to accumulate on the toner core before the coating layer is added, which prevents migration to the toner surface. Developer roller and filming blade

[068] The developer roller and film blade of Toner Example A and B and Comparative Toner Example I were also tested. The toners were each placed in a toner cartridge. Each cartridge was then inserted into a testing robot and run at 50 ppm. Periodically, each developer roller and film slide were visually examined to assess the amount of film toner in the components. The film toner level has been graded on a scale of 1 to 4, where a higher grade (eg 4) indicates more film and lower performance. Test results are shown in Table 1 below.

[069] As shown in Table 1, Examples of toners A and B, which include a borax coupling agent, showed improved film developer roll resistance and comparable film foil resistance compared to the Comparative Example toner. I.

[070] In order to further evaluate the performance of the borax coupling agent, comparative examples of additional toners were prepared using a coupling agent of zinc sulfate and aluminum sulfate, respectively, between the core and shell layers of the borax. toner. Comparative Example of toner II [96] Comparative Example toner II was prepared using a zinc sulfate coupling agent instead of a borax coupling agent. Polyester resin emulsion Example A was divided into two batches, 70:30 weight division, to form the toner core and shell, respectively. The total polyester content represented about 90.3% of total toner solids. Therefore, the first batch contained 63.2% total toner solids and the second batch contained 27.1% total toner solids. The components were added to a 2.5 liter reactor in the following percentages: the first batch of Example A polyester resin emulsion with 63.2 parts (of polyester by weight), 4.4 parts (of pigment by weight) of the cyan blue dispersion pigment Example, and 5 parts (of release agent by weight) of the emulsion wax example. Deionized water was then added so that the mixture contained about 12% to about 15% solids by weight.

[071] The mixture was heated in the reactor to 30 °C and a circulation circuit was started consisting of a high shear mixer and an acid addition pump. The mixture was sent through the circuit and the high shear strain mixer was set at 10,000 rpm. The acid was slowly added to the high shear mixer to evenly disperse the acid in the toner mixture so that there were no low pH pockets. The addition of acid took about 4 minutes with 175 g of 1% sulfuric acid solution. The circuit flow was then reversed to return the toner mixture to the reactor and the reactor temperature was increased to about 40 - 45 °C. Once the particle size reached 4.0 μm (number average), 5% (by weight) of a zinc sulfate solution (18 g of solution containing 0.9 g of zinc sulfate) was added. The zinc sulfate content represented about 0.3% by weight of the total toner solids. After the addition of zinc sulfate, the second batch of Example A polyester resin emulsion was added, which contained 27.1 parts (of polyester by weight). The mixture was stirred for about 5 minutes and the pH was monitored. Once the particle size reached 5.5 μm (number average), 4% NaOH was added to raise the pH to about 6.82 to stop particle growth. The reaction temperature was maintained for one hour. Particle size was monitored during this time period. Once particle growth stopped, the temperature was increased to 88 °C to cause the particles to coalesce. This temperature was maintained until the particles reached their desired circularity (about 0.97). The toner was then washed and dried.

[072] The dry toner had an average particle size volume of 5.87 μm and an average particle size number of 4.98 μm. Fines (< 2 μm) were present in 1.12% (by number) and the toner had a roundness of 0.972.

[073] Additional toners were made using the formulation and procedure of Comparative Toner Example II, except that the neutralization pH was changed to test the pH adjustment window. The results of these toners are shown in Table 2 below. Comparative Example of toner III

[074] Comparative Example III toner was prepared using an aluminum sulfate coupling agent instead of a borax coupling agent. Polyester resin emulsion Example A was divided into two batches, 70:30 weight division, to form the toner core and shell, respectively. The total polyester content represented about 90.3% of total toner solids. Therefore, the first batch contained 63.2% total toner solids and the second batch contained 27.1% total toner solids. Components were added to a 2.5 liter reactor in the following percentages: the first batch of Example A polyester resin emulsion with 63.2 parts (of polyester by weight), 4.4 parts (of pigment by weight) of the Example cyan blue pigment dispersion, and 5 parts (release agent, by weight) of the emulsion wax example. Deionized water was then added so that the mixture contained about 12% to about 15% solids by weight.

[075] The mixture was heated in the reactor to 30 °C and a circulation circuit was started consisting of a high shear mixer and an acid addition pump. The mixture was sent through the circuit and the high shear mixer was set at 10,000 rpm. The acid was slowly added to the high shear mixer to evenly disperse the acid in the toner mixture so that there were no low pH pockets. The addition of acid took about 4 minutes with 175 g of 1% sulfuric acid solution. The circuit flow was then reversed to return the toner mixture to the reactor and the reactor temperature was increased to about 40 - 45 °C. Once the particle size reached 4.0 μm (number average), 5% (by weight) of an aluminum sulfate solution (18 g of solution containing 0.9 g of aluminum sulfate) was added. The aluminum sulfate content represented about 0.3% by weight of the total toner solids. After the addition of aluminum sulfate, the second batch of Example A polyester resin emulsion was added, which contained 27.1 parts (of polyester, by weight). The mixture was stirred for about 5 minutes and the pH was monitored. Once the particle size reached 5.5 μm (number average), 4% NaOH was added to raise the pH to about 6.47 to stop particle growth. The reaction temperature was maintained for one hour. Particle size was monitored during this time period. Once particle growth stopped, the temperature was increased to 88 °C to cause the particles to coalesce. This temperature was maintained until the particles reached their desired circularity (about 0.97). The toner was then washed and dried.

[076] The dry toner had an average particle size volume of 6.10 μm and a number average particle size of 5.20 μm. Fines (< 2 μm) were present in 0.24% (by number) and the toner had a roundness of 0.970.

[077] Additional toners were made using the formulation and procedure of the Toner III comparative example, except the neutralization pH was changed to test the pH adjustment window. The results of these toners are shown in Table 2 below. Window for pH adjustment

[078] The results of the pH adjustment test referred to above window for Comparative Examples of toners I-III and Example of toner A, are shown in Figure 3 and Table 2, below. Specifically, Figure 3 shows a graph that summarizes the data presented in Table 2. Table 2

[079] As illustrated in Table 2 and Figure 3, the pH adjustment window for toners having a coupling agent (borax, zinc sulphate or aluminum sulphate) is significantly wider than the pH adjustment window. pH for the conventional emulsion aggregation toner of Comparative Toner Example I. As discussed above, when the pH adjustment window is wider, the process is easier to control on an industrial scale. merge window

Tabela 4

[080] Each toner composition was used to print 24# Hammermill (HMLP) laser paper using a fusing robot at 50 pages per minute (ppm) with a toner coverage of 1.1 mg/cm2 employing various fusing temperatures , as shown in Tables 3 and 4 below. The temperatures shown in Tables 3 and 4 are the melting temperatures of the robot's heating element/heater. For each toner composition, several degree of fusion measurements were performed. These degree of fusion measurements include a scratch resistance test shown in Table 3 and a conventional 60 degree gloss test shown in Table 4. For the scratch resistance test, print samples were evaluated using an abrasion device. of TABER ABRADER from TABER Industries, North Tonawanda, New York, USA. Printed samples were rated on the TABER ABRADER scale between 0 and 10 (where a rating of 10 indicates the most scratch resistant). The TABER ABRADER device scratches the printed samples several times with different strengths until the toner is scratched out of the sample. The point where the toner is crossed out corresponds to a number rating between 0 and 10 on the TABER ABRADER scale. As is known in the art, the conventional 60 degree gloss test includes shining a known amount of light onto the surface of the printed sheet from a 60 degree angle and measuring its reflectance. A higher test brightness value indicates that more energy was transferred to the substrate as it moved through the melt. Print gloss also refers to the resin and release agent used in the toner. Table 3

Table 4

[081] As shown in Table 3, Example toners A and B, which included a borax coupling agent and were formed using the same resin as Comparative Example toners I-III, showed superior melting performance compared to the toner. conventional emulsion aggregation (Comparative Example toner I) and toners with a coupling agent of zinc sulfate or aluminum sulfate (Comparative Examples of toners II and III). The low ends of the melt windows for Example A and B toners were lower than the low ends of the melt windows for Comparative Examples I-III. Specifically, Example A and B toners provided acceptable scratch resistance at temperatures as low as 200°C and 195°C, respectively. Comparative Examples of Toners I-III were unable to provide acceptable scratch resistance at these temperatures and instead showed cold bulge ("CO"), which means the toner did not fuse to the paper. Therefore, less energy was required to perform an acceptable melting operation for toner Examples A and B than for Comparative Toner Example I-III. Toner Examples A and B also provided improved scratch resistance at elevated temperatures from 210°C - 230°C compared to Comparative Toner Examples I-III.

[082] The toner cores of Examples C and D were formed using the same resin as in Toner Examples A and B and Comparative Examples of Toners I-III, but different resins were used to form the shells of the toners of Example C and D. However, as shown in Table 3, the low ends of the melt windows for Example C and D toners, which include a borax coupling agent, were lower than the low ends of the melt windows for Examples Comparatives I-III. Toner Examples C and D also exhibited improved scratch resistance at elevated temperatures from 210°C - 230°C compared to the comparative example toners I-III.

[083] Toner Example E was formed using a higher molecular weight resin having a higher glass transition temperature than the resin used to form toner Examples A and B and Comparative Toner Examples I-III. It will be appreciated by one of skill in the art that the higher molecular weight and higher glass transition temperature of this resin could compromise the low end of the melt window. Table 3 shows that Example Toners A and B outperformed Example toner E due to the lower molecular weight and lower glass transition temperature of the resin used in Example A and B toners. However, the melting performance of toner Example E, which included a borax coupling agent and a higher molecular weight and higher glass transition temperature resin, was comparable to the melting performance of Comparative Examples of toners I-III, although Comparative Examples of Toners I-III included a lower molecular weight resin and lower glass transition temperature.

[084] As shown in Table 4, toner Examples A through E exhibited comparable gloss test performance compared to Toner Comparative Example I. Toner Comparative Examples II and III showed poorer gloss values in comparison with Toner Examples A to E and Toner Comparative Example I.

[085] The foregoing description of various embodiments has already been presented for purposes of illustration. It is not intended to be exhaustive or to limit application to the precise forms disclosed and obviously many modifications and variations are possible in light of the above teachings. It is understood that the invention may be practiced in ways other than those specifically presented herein, without departing from the scope of the invention in ways. The scope of application is intended to be defined by the appended claims.

Claims (8)

1. Chemically prepared toner composition CHARACTERIZED in that it comprises: a core having an outer surface, the core having components including a first polymer binder having functional groups, a dye and a release agent; a borax coupling agent located on the outer surface of the core; and a shell formed around the outer surface of the core and the borax coupling agent, the shell including a second polymer binder having functional groups, wherein the borax coupling agent is located between the core and the shell and binds to shell to the outer surface of the core by forming a hydrogen bond between its hydroxyl groups and the functional groups present in the first and second polymers, and collects the core components of the toner in the core prior to the addition of the shell, thus reducing residual fine particles on toner. A chemically prepared toner composition according to claim 1, CHARACTERIZED in that the first polymer binder having functional groups and the second polymer binder having functional groups each include a polyester resin. A chemically prepared toner composition according to claim 2, CHARACTERIZED in that the first polymer binder having functional groups includes a first polyester resin or blend and the second polymer binder having functional groups includes a second resin of polyester or blend other than the first polyester resin or blend. A chemically prepared toner composition according to claim 1, CHARACTERIZED in that the first polymer binder having functional groups and the second polymer binder having functional groups each include a styrene polymer having functional groups. A chemically prepared toner composition according to claim 4, CHARACTERIZED in that the first polymer binder having functional groups includes a first styrene polymer having functional groups or mixture and the second polymer binder having functional groups includes a second styrene polymer having functional groups or mixture different from the first styrene polymer having functional groups or mixture. 6. Chemically prepared toner composition according to claim 1, CHARACTERIZED in that the ratio of the first polymer binder having functional groups to the second polymer binder having functional groups is between about 20:80 and about 80 :20 by weight. 7. Chemically prepared toner composition according to claim 6, CHARACTERIZED in that the ratio of the first polymer binder having functional groups to the second polymer binder having functional groups is between about 50:50 and about 80 :20 by weight. 8. Chemically prepared toner composition according to claim 1, CHARACTERIZED in that the core and shell include the same polymer binder having functional groups.

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