TONER AND EMULSION AGGREGATE TONER

Abstract

Toner comprising: a polymer resin, wherein the polymer resin is an unsaturated amorphous polyester resin; optionally a colorant; and a low molecular weight crystalline imide having a molecular mass of less than 1,000 g / mol, wherein the low molecular weight crystalline imide is N-benzylphthalimide of the following formula:

Description

BACKGROUND OF THE INVENTION Electrophotography is a method for visualizing image information by forming an electrostatic, latent image, currently used in various fields. The term "electrostatic" is generally used interchangeably with "electrophotographic." Electrophotography generally involves forming an electrostatic, latent image on a photoreceptor, followed by developing the image with a developer containing toner, transferring the image to a transfer material such as paper or a sheet, and fixing the image to the transfer material using heat, a solvent, pressure, and / or similar methods to obtain a permanent image. The crease fix minimum fixing temperature (MFT) is a measurement used to determine the performance and energy efficiency of a particular toner in combination with a specific paper type and a specific fuser (which fixes the toner to the paper). Crease fix MFT is measured by folding the paper over an area infill of an image and then rolling a defined mass over the folded area. The paper can also be folded using a commercially available folding machine, such as the Duplo D-590. A plurality of sheets of paper with images fixed over a wide range of fixing temperatures are prepared. The sheets of paper are then unfolded, and any toner that has detached from the paper is wiped from the surface.The crease is then optically compared to a reference chart that defines an acceptable degree of toner adhesion; alternatively, the crease can be quantified using computer-aided image analysis. The smaller the area of ​​toner loss, the better the toner adhesion, and the temperature required to achieve an acceptable degree of adhesion is defined as the crease fix MFT. Currently, ultra-low-melt (ULM) emulsion aggregation (EA) toners have a benchmark crease fix melting point (MFT) of approximately -20 °C compared to styrene / acrylate EA toners. This improved crease fix MFT performance allows for a reduction in fixer energy and extended fixer life compared to EA toners. There is a need to reduce the MFT even further, for example, by an additional 10 °C to 20 °C. JP S63-58 355 A relates to a powdered toner comprising a colouring agent and a binder, which contains an imide compound with a melting point of 50-150 °C. EP 1 118 644 A2 discloses a hot melt printing ink, in particular for gravure printing processes, comprising 50 to 80 wt.% solvent or solvent mixtures with a melting point of 65 to 109 °C and a viscosity of 2.9 to 20 mPas at 110 °C and 20 to 50 wt.% binder with a glass transition temperature TG of 30 to 65 °C. JP S63-240 560 A discloses a powder toner comprising a dye, a magnetic powder and a binder consisting of a resin of an imide compound with a melting point of 30-150 °C. BRIEF SUMMARY OF THE INVENTION In the embodiments, a toner is provided comprising a polymer resin, which is an unsaturated amorphous polyester resin, optionally a colorant, and a low molecular weight crystalline imide with a molecular mass of less than 1,000 g / mol, wherein the low molecular weight crystalline imide is N-benzylphthalimide of the following formula: Another embodiment provides an emulsion aggregation toner comprising an amorphous polymer resin, which is an unsaturated amorphous polyester resin, optionally a colorant, and a low molecular weight crystalline imide with a molecular mass of less than 500 g / ml and a melting point of less than approximately 120 °C, wherein the low molecular weight crystalline imide is N-benzylphthalimide of the following formula: wherein a mixture of the amorphous polymer resin and the low molecular weight crystalline imide is characterized by a reduction in the glass transition temperature of the amorphous polymer resin and the absence of a significant solid-to-liquid phase transition peak of the low molecular weight crystalline imide, determined by differential dynamic calorimetry, wherein the fixation enthalpy of the low molecular weight crystalline imide in the mixture measures less than 10% of the fixation enthalpy of the low molecular weight crystalline imide in pure form. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plot of the gloss as a function of the fuser roller temperature for a toner comprising N-benzylphthalimide; and Fig. 2 is a plot of the crease area as a function of the fuser roller temperature for determining the crease fix MFT for a toner comprising N-benzylphthalimide. DETAILED DESCRIPTION OF THE INVENTION According to the present disclosure, toners comprising low molecular weight crystalline imides are provided. In some embodiments, the toner can comprise low molecular weight crystalline imides and an unsaturated amorphous polymer resin, wherein a mixture of the unsaturated amorphous polymer resin and the low molecular weight crystalline imides is characterized by a reduction in the glass transition temperature of the unsaturated amorphous polymer resin and by the absence of a significant solid-to-liquid phase transition peak for the low molecular weight crystalline imide, as determined by differential scanning calorimetry. The absence of a significant solid-to-liquid phase transition peak can, for example, be attributed to the fact that the imide is not a significant solid-to-liquid phase transition peak.by means of the fixation enthalpy for the low molecular weight, crystalline imides in the mixture, which measures less than 20% of its initial value, in some embodiments less than 10% of its initial value, and in some embodiments less than 5% of its initial value, where the initial fixation enthalpy for the small molecule is measured independently; this indicates compatibility of the low molecular weight, crystalline imides with the amorphous polymer resin. Furthermore, in some embodiments, the low molecular weight, crystalline imides may have a melting point lower than the fixation temperature of the EA toner. According to some embodiments, emulsion aggregation (EA) toners comprising low molecular weight, crystalline imides can achieve crease fix MFT at least comparable to nominal ULM EA toners, such as the Xerox® 700 Digital Color Press (DCP) toner, available from Xerox Corp., if not, for example,by 5 °C or by 10 °C to 20 °C lower. For the processes of the present disclosure, an unsaturated amorphous polyester resin is used. Such resins can, in turn, be prepared from any suitable monomer or monomers via any suitable polymerization process. In some embodiments, the resin can be prepared by a process other than emulsion polymerization. In further embodiments, the resin can be prepared by condensation polymerization. In these embodiments, the resin is an unsaturated amorphous polyester resin. In these embodiments, the resin can be a mixture of crystalline and amorphous resins. The crystalline resin can be present in the mixture of crystalline and amorphous resins, for example, in an amount of 0 to approximately 50 percent by weight of the total toner resin, and in some embodiments, in an amount of 5 to approximately 35 percent by weight of the toner resin. The amorphous resin can be present in the mixture, for example, in an amount of approximately 50 to approximately 100 percent by weight of the total toner resin, and in some embodiments, in an amount of 95 to approximately 65 percent by weight of the toner resin. In the embodiments, the crystalline resin can be selected from the group consisting of polyester, polyamide, polyimide, polyethylene, polypropylene, polybutylene, polyisobutyrate, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer and mixtures thereof. In some embodiments, the resin can be a polyester resin formed by reacting a diol with a diacid in the presence of an optional catalyst. Suitable organic diols for forming a crystalline polyester include aliphatic diols with approximately 2 to approximately 36 carbon atoms, such as 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, combinations thereof, and similar compounds. The aliphatic diol can be selected, for example, in an amount of approximately 40 to approximately 60 mol percent, in some embodiments from approximately 42 to approximately 55 mol percent, and in some embodiments from approximately 45 to approximately 53 mol percent of the resin. Examples of organic diacids or diesters selected for the preparation of the crystalline resin include oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, fumaric acid, maleic acid, dodecanedionic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, cyclohexanedicarboxylic acid, malonic acid, and mesaconic acid, a diester or anhydride thereof, and combinations thereof. The organic diacid may be selected in some embodiments, for example, in an amount of approximately 40 to approximately 60 mol percent, in some embodiments from approximately 42 to approximately 55 mol percent, and in some embodiments from approximately 45 to approximately 53 mol percent. Examples of crystalline resins include polyesters, polyamides, polyimides, polyolefins, polyethylene, polybutylene, polyisobutyrate, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, polypropylene, mixtures thereof, and the like.Certain crystalline resins may be polyester based, such as poly(ethylene adipate), poly(propylene adipate), poly(butylene adipate), poly(pentylene adipate), poly(hexylene adipate), poly(octylene adipate), poly(ethylene succinate), poly(propylene succinate), poly(butylene succinate), poly(pentylene succinate), poly(hexylene succinate), Poly(octylene succinate), poly(ethylene sebacate), poly(propylene sebacate), poly(butylene sebacate), poly(pentylene sebacate), poly(hexylene sebacate), poly(octylene sebacate), alkali-copoly(5-sulfoisophthaloyl)-copoly(ethylene adipate), poly(decylene sebacate), poly(decylene canedioate), Poly(ethylene decanecanedioate), poly(ethylene endodecanedioate), poly(nonylene sebacate), poly(nonylenedecanedioate), poly(nonylenedodecanedioate), Poly(decylendodeanedioate), copoly(ethylene fumarate)-copoly(ethylene sebacate), copoly(ethylene fumarate)-copoly(ethylene decanedioate), and copoly(ethylene fumarate)-copoly(ethylene endodecanedioate). The crystalline resin, when used, can be found, for example, in quantities of approximately 5 to approximately...50 percent by weight of the toner components are present, in some embodiments from approximately 10 to approximately 35 percent by weight of the toner components. The crystalline resin can have different melting points, e.g., from approximately 30 °C to approximately 120 °C, and in some embodiments from approximately 50 °C to approximately 90 °C. The crystalline resin can have a number-average molecular mass (Mn), as measured by gel permeation chromatography (GPC), e.g., from approximately 1,000 to approximately 50,000, and in some embodiments from approximately 2,000 to approximately 25,000, and a mass-average molecular mass (Mw), e.g., from approximately 2,000 to approximately 100,000, and in some embodiments from approximately 3,000 to approximately 80,000, as determined by gel permeation chromatography using polystyrene standards. The molecular mass distribution (Mw / Mn) of the crystalline resin can be, for example, from approximately 2 to approximately 6, and in some embodiments from approximately 2 to approximately 4. Examples of diacids or diesters selected for the preparation of amorphous polyesters include dicarboxylic acids or diesters such as terephthalic acid, phthalic acid, isophthalic acid, fumaric acid, maleic acid, succinic acid, itaconic acid, succinic acid, succinic anhydride, dodecenyl succinic acid, dodecenyl succinic anhydride, glutaric acid, glutaric anhydride, adipic acid, pimelic acid, suberic acid, azelaic acid, dodecanedioic acid, dimethyl terephthalate, diethyl terephthalate, dimethyl isophthalate, diethyl isophthalate, dimethyl phthalate, phthalic anhydride, diethyl phthalate, dimethyl succinate, dimethyl fumarate, dimethyl maleate, dimethyl glutarate, dimethyl adipate, dimethyl dodecenyl succinate, and combinations thereof. The organic diacids or diesters can be present, for example, in an amount of approximately 40 to approximately 60 mol percent of the resin, in some embodiments from approximately 42 to approximately 55 mol percent of the resin, and in some embodiments from approximately 45 to approximately 53 mol percent of the resin. Examples of diols used to produce the amorphous polyester include 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, pentanediol, hexanediol, 2,2-dimethylpropanediol, 2,2,3-trimethylhexanediol, heptanediol, dodecanediol, bis(hydroxyethyl)bisphenol A, bis(2-hydroxypropyl)bisphenol A, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, xylenedimethanol, cyclohexanediol, diethylene glycol, bis(2-hydroxyethyl) oxide, dipropylene glycol, dibutylene glycol and combinations thereof. The amount of the selected organic diol can vary and may be present, for example, in an amount of approximately 40 to 60 mol percent of the resin, in some embodiments in an amount of approximately 42 to approximately 55 mol percent of the resin, and in some embodiments in an amount of approximately 45 to approximately 53 mol percent of the resin. In some embodiments, polycondensation catalysts can be used for the formation of the polyesters. Polycondensation catalysts, which can be used for either the crystalline or amorphous polyesters, include tetraalkyl titanates, dialkyltin oxides such as dibutyltin oxide, tetraalkyltins such as dibutyltin dilaurate, and dialkyltin oxide hydroxides such as butyltin oxide hydroxide, tin octoate, aluminum alkoxides, alkylzinc, dialkylzinc, zinc oxide, tin oxide, or combinations thereof. Such catalysts can be used, for example, in amounts from approximately 0.01 mol% to approximately 5 mol% based on the starting diacid used to produce the polyester resin. An unsaturated, amorphous polyester resin is used as the latex resin. Examples of such resins include those disclosed in US 6,063,827 A. Examples of unsaturated amorphous polyester resins include, but are not limited to, poly(propoxylated bisphenol co-fumarate), poly(ethoxylated bisphenol co-fumarate), poly(butyloxylated bisphenol co-fumarate), poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-fumarate), poly(1,2-propylene fumarate), poly(propoxylated bisphenol co-maleate), poly(ethoxylated bisphenol co-maleate), poly(butyloxylated bisphenol co-maleate), poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-maleate), poly(1,2-propylene maleate), poly(propoxylated bisphenol co-itaconate), poly(ethoxylated bisphenol co-itaconate), poly(butyloxylated bisphenol co-itaconate), poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-itaconate), and poly(1,2-propylene itaconate). Combinations thereof. The amorphous resin can have different glass transition temperatures (Tg) from, for example, approximately 40 °C to approximately 100 °C, in some embodiments from approximately 45 °C to approximately 70 °C, and in some embodiments from approximately 50 °C to approximately 65 °C. The crystalline resin can have a number-average molecular mass (Mn) of, for example, approximately 1,000 to approximately 50,000, in some embodiments of approximately 2,000 to approximately 10,000, and a mass-average molecular mass (Mw) of, for example, approximately 2,000 to approximately 100,000, in some embodiments of approximately 3,000 to approximately 80,000, and in some embodiments of approximately 4,000 to approximately 20,000, as determined by gel permeation chromatography (GPC) using polystyrene standards. The molecular mass distribution (Mw / Mn) of the crystalline resin can be, for example, approximately 2 to approximately 6, in some embodiments of approximately 2 to approximately 5, and in some embodiments of approximately 2 to approximately 4. In some embodiments, an amorphous polyester resin may be, for example, a poly(propoxylated bisphenol A co-fumarate) resin with the following formula (1): where m is approximately 5 to approximately 1,000, in some embodiments approximately 10 to approximately 500, and in other embodiments approximately 15 to approximately 200. Examples of such resins and processes for their production include those disclosed in US 6,063,827 A. An example of a linear propoxylated bisphenol A fumarate resin that can be used as a toner resin is available under the brand name SPARII from Resana S / A Industrias Quimicas, Sao Paulo, Brazil. Other propoxylated bisphenol A fumarate resins that can be used and are commercially available include GTUF and FPESL-2 from Kao Corporation, Japan, and EM181635 from Reichhold, Research Triangle Park, North Carolina, and similar products. In some embodiments, the amorphous polyester resin can be a copolymer of alkoxylated bisphenol A with at least one diacid. The alkoxylated bisphenol A can comprise ethoxylated bisphenol A, propoxylated bisphenol A, and / or ethoxylated-propoxylated bisphenol A. Suitable diacids include fumaric acid, terephthalic acid, dodecenyl succinic acid, and / or trimellitic acid. In some embodiments, a combination of low-molecular-weight and high-molecular-weight amorphous resins can be used to form a toner. Low-molecular-weight resins can have a mass-average molecular weight of approximately 10 kg / mol to approximately 20 kg / mol and a number-average molecular weight of approximately 2 kg / mol to approximately 5 kg / mol. High-molecular-weight resins can have a mass-average molecular weight of approximately 90 kg / mol to approximately 160 kg / mol and a number-average molecular weight of approximately 4 kg / mol to approximately 8 kg / mol. The ratio of low-molecular-weight to high-molecular-weight resins can be approximately 0:100 to approximately 100:0, in some embodiments approximately 70:30 to approximately 30:70, and in other embodiments approximately 60:40 to approximately 40:60. Further examples of usable crystalline resins, optionally in combination with an amorphous resin as described above, include those disclosed in US 2006 / 0222991 A1. In some embodiments, a suitable crystalline resin may comprise a resin formed from ethylene glycol and a mixture of dodecanedionic acid and fumaric acid co-monomers having the following formula (2): where b is approximately 5 to approximately 2,000 and d is approximately 5 to approximately 2,000. In some embodiments, for example, a poly(propoxylated bisphenol A co-fumarate) resin of formula I, as described above, can be combined with a crystalline resin of formula II to form a resin suitable for forming a toner. Examples of other toner resins or polymers that can be used include those based on styrenes, acrylates, methacrylates, butadienes, isoprenes, acrylic acids, methacrylic acids, acrylonitriles and combinations thereof. Examples of other resins or polymers include, but are not limited to, poly(styrene butadiene), poly(methyl styrene 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(methyl styrene 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 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), and 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 acrylonitrile), and poly(styrene butyl acrylate acrylonitrile acrylic acid, and combinations thereof. The polymer can be a block, random, or alternating copolymer. In further embodiments, resins used in the toner can have a melting viscosity of approximately 10 to approximately 1,000,000 Pascal seconds (Pa · s) at approximately 130 °C, and in some embodiments of approximately 20 to approximately 100,000 Pa · s. One, two, or more toner resins can be used. In embodiments where two or more toner resins are used, the toner resins can be present in any desired ratio (e.g., mass ratio), such as approximately 10% (first resin) / 90% (second resin) to approximately 90% (first resin) / 10% (second resin). In the embodiments, the polymer latex can be formed by means of an emulsification process. When using such processes, the resin can be present in a resin emulsion, which can then be combined with other components and additives to form a toner of the present disclosure. The polymer resin can be present in an amount of approximately 65 to approximately 95% by weight of the solid-based toner particles (i.e., toner particles without external additives) in some embodiments, approximately 70 to approximately 90% by weight in some embodiments, and approximately 75 to approximately 85% by weight in other embodiments. If the resin is a combination of crystalline resin and one or more amorphous resins, the ratio of crystalline resin to amorphous resin(s) can be approximately 1:99 to approximately 30:70 in some embodiments, approximately 5:95 to approximately 25:75 in some embodiments, and approximately 5:95 to approximately 15:85 in other embodiments. In some embodiments, resins, colorants, waxes, and other additives used to form toner compositions can be present in dispersions containing surfactants. Furthermore, toner particles can be formed by emulsion aggregation processes, wherein the resin and other components of the toner are introduced into one or more surfactants, an emulsion is formed, toner particles are aggregated, fused, and optionally washed, dried, and recovered. One, two, or more surfactants can be used. The surfactants can be selected from ionic and non-ionic surfactants. Anionic and cationic surfactants are included under the term "ionic surfactants." In some embodiments, the surfactant can be used in an amount of approximately 0.01% to approximately 5% based on the mass of the toner composition, e.g., from approximately 0.75% to approximately 4% based on the mass of the toner composition, and in some embodiments from approximately 1% to approximately 3% based on the mass of the toner composition. Examples of usable non-ionic surfactants include, for example, polyacrylic acid, methalose, methylcellulose, ethylcellulose, propylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyoxyethylene encetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether, polyoxyethylene nonyl phenyl ether, and dialkylphenoxypoly(ethyleneoxy)ethanol, available from Rhone-Poulenc 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™. Other examples of suitable nonionic surfactants include a block copolymer of polyethylene oxide and polypropylene oxide, including those commercially available as SYNPERONIC PE / F, in some embodiments as SYNPERONIC PE / F 108. Suitable anionic surfactants include sulfates and sulfonates, sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate, sodium dodecylnaphthalene sulfate, dialkylbenzenealkyl sulfates and sulfonates, acids such as abietic acid (available from Aldrich), NEOGEN R™, NEOGEN SC™ (available from Daiichi Kogyo Seiyaku), combinations thereof, and similar substances. Other suitable anionic surfactants include, in some embodiments, DOWFAX™ 2A1, an alkyldiphenyl oxide disulfonate from The Dow Chemical Company, and / or TAYCA POWER BN2060 from Tayca Corporation (Japan), which are branched sodium dodecylbenzenesulfonates. Combinations of these surfactants and all of the aforementioned anionic surfactants may be used in the embodiments. Examples of cationic surfactants that are typically positively charged include alkylbenzyldimethylammonium chloride, dialkylbenzenealkylammonium chloride, lauryltrimethylammonium chloride, alkylbenzylmethylammonium chloride, alkylbenzyldimethylammonium bromide, benzalkonium chloride, cetylpyridinium bromide, C12, C15, C17 trimethylammonium bromides, halogen salts of quaternary polyoxyethylalkylamines, dodecylbenzyltriethylammonium chloride, MIRAPOL™ and ALKAQUAT™, available from Alkaril Chemical Company, SANIZOL™ (benzalkonium chloride), available from Kao Chemicals, and similar compounds and mixtures thereof. If an optional colorant is to be added, various known, suitable colorants can be contained in the toner, such as dyes, pigments, mixtures of dyes, mixtures of pigments, mixtures of dyes and pigments, and similar substances. The colorant may be present in the toner in an amount ranging from, for example, 1 to approximately 15 percent by weight of the toner, or from approximately 3 to approximately 10 percent by weight. Examples of suitable colorants include: Carbon Black, such as REGAL 330®; Magnetite, such as Mobay Magnetite MO8029™, MO8060™; Columbian Magnetite; MAPICO BLACKS™ and surface-treated Magnetite; Pfizer Magnetite CB4799™, CB5300™, CB5600™, MCX6369™; Bayer Magnetite, BAYFERROX 8600™, 8610™; Northern Pigments Magnetite, NP-604™, NP-608™; Magnox Magnetite TMB-100™ or TMB-104™; and similar. Color pigments can include cyan, magenta, yellow, red, green, brown, blue, or mixtures thereof. Generally, cyan, magenta, or yellow pigments or dyes, or mixtures thereof, are used. The pigment(s) are generally used as water-based pigment dispersions. Specific examples of pigments include SUNSPERSE 6000, FLEXIVERSE and AQUATONE, water-based pigment dispersions from SUN Chemicals; HELIOGEN BLUE L6900™, D6840™, D7080™, D7020™; PYLAM OIL BLUE™; PYLAM OIL YELLOW™; PIGMENT BLUE 1™, available from Paul Uhlich & Company, Inc.; PIGMENT VIOLET 1™; PIGMENT RED 48™; LEMON CHROME YELLOW DCC 1026™; ED TOLUIDINE RED™; and BON RED C™, available from Dominion Color Corporation, Ltd., Toronto, Ontario; NOVAPERM YELLOW FGL™; HOSTAPERM PINK E™, from Hoechst; and CINQUASIA MAGENTA™, available from E.I. DuPont de Nemours & Company, and similar dyes. Generally, selectable colorants are black, cyan, magenta, or yellow, and mixtures thereof. Examples of magenta include 2,9-dimethyl-substituted quinacridone and anthraquinone dyes, identified in the Color Index as CI 60710, CI Dispersed Red 15, and diazo dye, identified in the Color Index as CI 26050, CI Solvent Red 19.and similar pigments. Illustrative examples of cyans include copper tetra(octadecylsulfonamido)phthalocyanine, x-copper phthalocyanine pigment listed in the Color Index as CI 74160, CI Pigment Blue, CI Pigment Blue 15:3, and anthrathrene blue, identified in the Color Index as CI 69810, Special Blue X-2137, and similar pigments. Illustrative examples of yellows include diarylide yellow 3,3-dichlorobenzidene acetoacetanilide, a monoazo pigment identified in the Color Index as CI 12700, CI Solvent Yellow 16, a nitrophenylamine sulfonamide identified in the Color Index as Foron Yellow SE / GLN, CI Dispersed Yellow 33 2,5-dimethoxy-4-sulfonanilide phenylazo-4'-chloro-2,5-dimethoxyacetoacetanilide, and Permanent Yellow FGL. Colored magnetites, such as mixtures of MAPICO BLACK™, and cyan components can also be used as colorants. Other well-known colorants can be selected, such as Levanyl Black A-SF (Miles, Bayer) and Sunsperse Carbon Black LHD 9303 (Sun Chemicals).und farbige Farbstoffe, wie Neopen Blue (BASF), Sudan Blue OS (BASF), PV Fast Blue B2G01 (American Hoechst), Sunsperse Blue BHD 6000 (Sun Chemicals), Irgalite Blue BCA (Ciba-Geigy), Paliogen Blue 6470 (BASF), Sudan III (Matheson, Coleman, Bell), Sudan II (Matheson, Coleman, Bell), Sudan IV (Matheson, Coleman, Bell), Sudan Orange G (Aldrich), Sudan Orange 220 (BASF), Paliogen Orange 3040 (BASF), Ortho Orange OR 2673 (Paul Uhlich), Paliogen Yellow 152, 1560 (BASF), Lithol Fast Yellow 0991K (BASF), Paliotol Yellow 1840 (BASF), Neopen Yellow (BASF), Novoperm Yellow FG 1 (Hoechst), Permanent Yellow YE 0305 (Paul Uhlich), Lumogen Yellow D0790 (BASF), Sunsperse Yellow YHD 6001 (Sun Chemicals), Suco-Gelb L1250 (BASF), Suco-Yellow D1355 (BASF), Hostaperm Pink E (American Hoechst), Fanal Pink D4830 (BASF), Cinquasia Magenta (DuPont), Lithol Scarlet D3700 (BASF), Toluidine Red (Aldrich), Scarlet for Thermoplast NSD PS PA (Ugine Kuhlmann of Canada), E.D. Toluidine Red (Aldrich),Lithol Rubine Toner (Paul Uhlich), Lithol Scarlet 4440 (BASF), Bon Red C (Dominion Color Company), Royal Brilliant Red RD-8192 (Paul Uhlich), Oracet Pink RF (Ciba-Geigy), Paliogen Red 3871K (BASF), Paliogen Red 3340 (BASF), Lithol Fast Scarlet L4300 (BASF), combinations thereof and similar products. Optionally, a wax can be combined with the resin, and optionally a colorant, to form toner particles. If included, the wax can be present in an amount ranging from, for example, 1% by weight to approximately 25% by weight of the toner particles, and in some embodiments from approximately 5% by weight to approximately 20% by weight of the toner particles. Waxes that can be selected have, for example, a mean molecular weight (Mw) of approximately 500 to approximately 20,000, and in some embodiments of approximately 1,000 to approximately 10,000. Waxes that can be used include, for example, polyolefins such as polyethylene, polypropylene, and polybutene waxes, such as those commercially available from Allied Chemical and Petrolite Corporation, e.g., POLYWAX™ polyethylene waxes from Baker Petrolite, wax emulsions available from Michaelman, Inc. and the Daniels Products Company, EPOLENE N-15™, commercially available from Eastman Chemical Products, Inc., and VISCOL 550-P™, a low mean molecular weight polypropylene, available from Sanyo Kasei KK.; plant-based waxes, such as carnauba wax, rice wax, candelilla wax, sumac wax and jojoba oil; animal-based waxes, such as beeswax; mineral-based and petroleum-based waxes, such as montan wax, ozokerite, keresin, paraffin wax, microcrystalline wax and Fischer-Tropsch wax; ester waxes obtained from higher fatty acids and higher alcohols, such as stearyl stearate and behenyl behenate; ester waxes obtained from higher fatty acids and monovalent or multivalent lower alcohols, such as butyl stearate, propyl oleate, glyceride monostearate, glyceride distearate and pentaerythritol tetrabehenate; Ester waxes are obtained from higher fatty acids and multivalent alcohol multimers, such as diethylene glycol monostearate, dipropylene glycol distearate, diglyceryl distearate, and triglyceryl tetrastearate; sorbitan higher fatty acid ester waxes, such as sorbitan monostearate, and cholesterol higher fatty acid ester waxes, such as cholesteryl stearate. Examples of usable functionalized waxes include, for example...Amines, amides, e.g., AQUA SUPERSLIP 6550™, SUPERSLIP 6530™, available from Micro Powder Inc.; fluorinated waxes, e.g., POLYFLUO 190™, POLYFLUO 200™, POLYSILK 19™, POLYSILK 14™, available from Micro Powder Inc.; mixed fluorinated amide waxes, e.g., MICROSPERSION 19™, also available from Micro Powder Inc.; imides, esters, quaternary amines, carboxylic acids, or acrylic polymer emulsions, e.g., JONCRYL 74™, 89™, 130™, 537™, and 538™, all available from SC Johnson Wax; and chlorinated polypropylenes and polyethylenes, available from Allied Chemical and Petrolite Corporation and SC Johnson Wax. Mixtures and combinations of the aforementioned substances can also be used in the embodiments. Waxes, for example, can be used as fixing roller release agents. In some embodiments, a shell can be applied to the formed, aggregated toner particles. Any of the resins described above that are suitable for the core resin can also be used as the shell resin. The shell resin can be applied to the aggregated particles by any method known to those skilled in the art. In some embodiments, the shell resin can be an emulsion that may contain any surfactant described above. The aggregated particles described above can be combined with the emulsion so that the resin forms a shell around the formed aggregates. The aggregated particles from above can be combined with the emulsion so that the resin forms a shell around the formed aggregates. In these embodiments, at least one amorphous polyester resin can be used to form a shell around the aggregates in order to form toner shell particles with a core-shell configuration.In the embodiments, an amorphous polyester resin and a crystalline resin can be used to form a shell around the aggregates, creating toner shell particles with a core-shell configuration. In some embodiments, a suitable shell can contain at least one amorphous polyester resin, which may be present in an amount of approximately 10% to approximately 90% by weight of the shell, in some embodiments from approximately 20% to approximately 80% by weight of the shell, and in some embodiments from approximately 30% to approximately 70% by weight of the shell. The casing resin can be present in an amount of approximately 5% to approximately 40% by weight of the toner particles, and in some embodiments from approximately 24% to approximately 30% by weight of the toner particles. Once the desired final toner particle size is reached, the pH of the mixture with base can be adjusted to a value of approximately 5 to 10, or in some embodiments, approximately 6 to 8. Adjusting the pH can be used to freeze, or stop, toner growth. The base used to stop toner growth can be any suitable base, such as alkali metal hydroxides like sodium hydroxide, potassium hydroxide, ammonium hydroxide, combinations thereof, and the like. The base can be added in amounts of approximately 2 to 25% by weight of the mixture, or in some embodiments, approximately 4 to 10% by weight. Furthermore, the addition of an EDTA solution can be used to freeze shell growth. In some embodiments, a combination of EDTA solution and base solution can be used to freeze toner particle growth. In some embodiments, low-molecular-weight, crystalline imide compounds, which are crystalline solids at room temperature, are added to the toner to lower the minimum fixing temperature (MFT). In certain embodiments, the low-molecular-weight, crystalline imide compounds are added to emulsion aggregation (EA) toners, replacing a crystalline polymer component completely or partially, if present, provided that the low-molecular-weight, crystalline imide compounds are compatible with the amorphous binder resin(s). Compatibility can be demonstrated by characterizing a melt mixture of the amorphous resin and the low-molecular-weight, crystalline imide compound(s).The low-molecular-weight, crystalline imide compounds are considered compatible if the melt mixture is characterized by a reduction in the glass transition temperature compared to that of the amorphous resin and by the absence of a significant solid-to-liquid phase transition peak for the low-molecular-weight, crystalline imide compound(s), as determined by differential scanning calorimetry, wherein the fixation enthalpy for the low-molecular-weight, crystalline imide compound in the mixture measures less than 20% of the initial value, in some embodiments less than 10% of the initial value, and in some embodiments less than 5% of the initial value, where the initial value represents the fixation enthalpy for the small molecule when measured independently. Furthermore, in some embodiments, the low-molecular-weight, crystalline imide compounds exhibit a melting point lower than the fixation temperature of the EA toner.According to some embodiments, emulsion aggregation toners comprising low molecular weight crystalline imide compounds can achieve a crease fix MFT that is at least comparable to nominal ULM toners, such as the Xerox® 700 DCP toner available from Xerox Corp, if not, for example, at least 5 °C or 10 °C to 20 °C lower. In some embodiments, the low molecular weight, crystalline imide compounds have a molecular mass of less than 1,000 g / mol; in further embodiments, the low molecular weight, crystalline imide compounds have a molecular mass of less than 750 g / mol; in further embodiments, the low molecular weight, crystalline imide compounds have a molecular mass of less than 500 g / mol. The compatibility test for the amorphous resin and the low-molecular-weight crystalline imide compounds will be performed shortly as follows. A low-molecular-weight crystalline imide compound will be mixed with an amorphous resin in a ratio similar to that found in the toner itself. The mixture will be heated to a temperature at least above the melting point of the crystalline component for a period sufficient for complete melting and mixing, and then cooled to room temperature. The resulting material will be analyzed using DDK.This test assumes that small molecules incompatible with the resin recrystallize from the molten mixture upon cooling, so the DDK trace shows both (1) a distinct melting peak corresponding to the small molecule and (2) the initial glass transition temperature of the amorphous resin (which may, but does not have to, be shifted to a slightly lower temperature). When small molecules with these properties are incorporated into an EA toner, they generally do not provide the characteristics of a low-melting toner. Conversely, small molecules compatible with the resin generally do not crystallize from the molten mixture. In these cases, the DKK traces show both (1) a weak or completely absent melt transition and (2) a weak and / or shifted glass transition, indicating the plasticization of the amorphous resin by the small molecule.When these small molecules are incorporated into an EA toner, they generally exhibit low-melting-point toner properties as long as the melting point of the small molecule is below the typical fixing temperature of the toner (approximately 110°C to 120°C for a typical ULM EA toner, such as the Xerox® 700 DCP toner). Furthermore, the degree of compatibility can be measured by determining the enthalpy of crystallization. Complete compatibility is achieved with a value of less than 5% of the initial value, while complete incompatibility requires a value above 20% of the initial value, where the initial value represents the fixing enthalpy for the small molecule when measured independently. The low molecular weight, crystalline imide is N-benzylphthalimide (melting point 119 °C) of the following formula: The toner particles can be prepared by any prior art method. Although embodiments relating to toner particle production are described below with respect to emulsion aggregation processes, any suitable method for producing toner particles can be used, including chemical processes such as suspension and encapsulation processes, as disclosed, for example, in US 5,290,654 A and US 5,302,486 A. In some embodiments, the toner compositions and toner particles can be prepared by aggregation and fusion processes in which low-molecular-weight particles are aggregated to the appropriate toner particle size and then fused to obtain the final toner particle shape and morphology. In some embodiments, the toner compositions can be prepared by emulsion aggregation processes, such as a process that includes aggregating a mixture of an optional colorant, an optional wax, and other desired or required additives, as well as emulsions, including resins and at least one or more of the low-molecular-weight, crystalline imide compounds described above, optionally in surfactants as described above, and then fusing the aggregate mixture. Examples of possible, suitable colorants, waxes, and / or other additives are described above. In some embodiments, the low-molecular-weight molecule(s) constitute approximately 5% to approximately 25% of the dry weight of the toner, excluding any external additives; in some embodiments, approximately 10% to 20%; and in other embodiments, the low-molecular-weight molecule(s) constitute approximately 15% of the dry weight of the toner.In some embodiments, the emulsions for each of the components are prepared and then combined. Furthermore, in some embodiments, the toner comprises both a low-molecular-weight, crystalline imide compound and a crystalline resin. The crystalline resin can be, for example, the crystalline polyester resin described above and / or any other crystalline resin described herein. In some embodiments, the crystalline resin constitutes approximately 3% to approximately 20% of the dry mass of the toner, excluding any external additives; in some embodiments, approximately 5% to approximately 15%; and in some embodiments, the low-molecular-weight, crystalline imide compound(s) constitute approximately 5% to approximately 10% of the dry mass of the toner. A mixture can be prepared by adding optional colorants, waxes, and / or other materials, which may also be present in dispersions, including a surfactant, to the emulsion, which may be a mixture of two or more emulsions containing the resin. The pH of the resulting mixture can be adjusted as required. Following the preparation of the above mixture, an aggregating agent or flocculant can be added. Any suitable aggregating agent can be used to form the toner. Suitable aggregating agents include, for example, aqueous solutions of a divalent cation or a multivalent cationic material. The aggregating agent can be, for example, a polyaluminum halogen, such as polyaluminum chloride (PAC) or the corresponding bromide, fluoride, or iodide; a polyaluminum silicate, such as polyaluminum sulfosilicate (PASS); and a water-soluble metal salt, such as aluminum chloride, aluminum nitrite, aluminum sulfate, potassium aluminum sulfate, calcium acetate, calcium chloride, calcium nitrite, calcium oxylate, calcium sulfate, magnesium acetate, magnesium nitrate, magnesium sulfate, zinc acetate, zinc nitrate, zinc sulfate, zinc chloride, zinc bromide, magnesium bromide, copper chloride, copper sulfate, and combinations thereof.In some embodiments, the aggregating agent can be added to the mixture at a temperature below the glass transition temperature (Tg) of the resin. The particles can aggregate until a predetermined, desired particle size is reached. A predetermined, desired particle size refers to the desired particle size to be achieved, which is determined before formation, and the particle size is monitored during the growth process until this size is reached. During the growth process, samples can be taken and analyzed for the mean particle size, e.g., using a Coulter counter. Aggregation can thus continue by maintaining the elevated temperature, or, if necessary, by slowly increasing the temperature and maintaining the mixture at that temperature, while continuously stirring to provide the aggregated particles.Once the predetermined, desired particle size is reached, emulsions of the resins are added to allow a shell to grow, thus providing particles with a core-shell structure. The shell grows until the desired core-shell toner particle size is reached, then the growth process is stopped by increasing the pH of the reaction slurry by adding a base, such as NaOH, followed by the addition of an EDTA solution. Once particle growth has stopped, the reaction mixture is heated to, for example, 85 °C to fuse the particles. The toner slurry is then cooled to room temperature, and the toner particles are separated by sieving and filtration, followed by washing and freeze-drying. The properties of the toner particles can be determined using any suitable technique and any suitable apparatus, as described in more detail below. The examples given below illustrate various compositions and conditions that may be used in carrying out the present embodiments. All dimensions are per mass unless otherwise noted. However, it is obvious that the present embodiments can be carried out with many types of composition and may have many different applications as disclosed above and as described herein. Compatibility studies of examples of the aforementioned low-molecular-weight, crystalline imide compounds and an amorphous polyester toner-binding resin were investigated by separately melt-mixing the low-molecular-weight, crystalline imide compounds with a low-molecular-weight, amorphous resin A (an alkoxylated bisphenol A copolyester with fumaric, terephthalic, and dodecenyl succinic acids). The melt mixing was performed on a hot plate at 150 °C for 20 minutes, followed by cooling and characterization by DDK. The low-molecular-weight, crystalline imide used in this example is N-benzylphthalimide. Compatibility studies of this imide and an amorphous polyester toner-binding resin A were investigated using DDK. The low-molecular-weight, crystalline imide exhibits a sharp melting transition at 119 °C and recrystallization at 72 °C; the linear amorphous resin A shows a glass transition temperature Tg of approximately 60 °C. For the mixture of the low-molecular-weight, crystalline imide N-benzylphthalimide and the linear amorphous polyester resin A, a glass transition of approximately 29 °C and no melting transition were observed using DDK, indicating complete compatibility. Example 1 Preparation of an N-benzylphthalimide dispersion A 250 ml plastic bottle containing approximately 700 g of stainless steel spheres was filled with 10.33 g of N-benzylphthalimide (obtained from TCI America), 1.98 g of the non-ionic surfactant DOWFAX (available from The Dow Chemical Co., 47 wt%), and 70 g of deionized water (DIW). The bottle was then ground for 7 days. A dispersion of particle sizes with a mean particle diameter of 414 nm was obtained. Example 2 Preparation of a toner comprising 15% N-benzylphthalimide Into a 2-liter glass reactor with an overhead mixer, 493.32 g of N-benzylphthalimide dispersion of Example 1 (2.32 wt%), 43.08 g of high molecular weight amorphous resin B in an emulsion (35.22 wt%), 43.63 g of low molecular weight linear amorphous resin A in an emulsion (34.84 wt%), 21.39 g of wax dispersion (wax available from International Group Inc., 30.19 wt%), and 24.38 g of cyanopigment PB15:3 (17.21 wt%) were added. The linear amorphous resin B is a co-polyester of alkoxylated bisphenol A with terephthalic acid and dodecenyl succinic acid. Separately, 2.51 g of Al2(SO4)3 (27.85 wt%) were added as a flocculant during homogenization at 3,500 rpm. The mixture was heated to 43 °C to aggregate the particles while stirring at 200 rpm.The particle size was monitored with a Coulter counter until the core particles reached a volume-averaged particle size of 4.05 µm with a GSD volume of 1.30. A mixture of 28.38 g and 28.75 g each of the previously mentioned resin emulsions A and B was then added as shell material, resulting in core-shell structured particles with a mean particle size of 6.21 µm and a GSD volume of 1.25. The pH of the reaction slurry was then raised to 8 using 4 wt% NaOH solution followed by 5.39 g EDTA (39 wt%) to freeze toner growth. After freezing, the reaction mixture was heated to 85 °C, and the toner particles were fused at 85 °C, pH 7.7. The toner was quenched after fusing, resulting in a final particle size of 8.15 µm, GSD volume of 1.36 and GSD number of 1.35.The toner slurry was then cooled to room temperature, separated by sieving (25 µm), filtered, then washed and freeze-dried. The toner from Example 2 was evaluated using the fuser unit of a Xerox® 700 Digital Color Press printer. The toners were fused at 220 mm / s onto Color Xpressions® paper (90 gsm) with a toner mass per unit area (TMA) of 1.00 mg / cm² for gloss, MFT, cold offset, and hot offset performance. The control toners were a Xerox® 700 DCP toner, comprising a crystalline resin with a melting point of 65°C to 85°C, and a Xerox® EA high-gloss (HG) toner, as used in the Xerox® DC250 printer. The fuser roller temperature was varied from cold offset to hot offset (up to 210°C) for gloss and crease measurements. The toner fusing performance is shown in Figures 1 and 2. Figures 1 and 2 show plots of the print gloss and print crease areas versus the fixer temperature for the toner from Example 2 with 15% N-benzylphthalimide and Xerox® High Gloss Toner, and the ULM EA Xerox® 700 DCP Toner. Compared to controls, the toner with N-benzylphthalimide shows slightly lower gloss and lower crease fix MFT. Remarkably, the experimental toner exhibits a very low cold offset temperature and a high hot offset temperature, thus providing an unexpectedly large fixer width. Toner samples, as described above, were mixed with Xerox® 700 DCP additives and carrier to provide developer samples. The developer samples were conditioned overnight in A and J zones and then charged for approximately 60 minutes using a Turbula mixer. The A zone is a high-humidity zone at approximately 28°C and 85% relative humidity (RH), and the J zone is a low-humidity zone at approximately 21°C and 10% RH. The toner charge (Q / d) was measured using a charge spectrograph in a 100 V / cm field and was also measured visually as the center point of the toner charge distribution. The toner charge-mass ratio (Q / m) was determined using the total blow-off method, where the charge was measured on a Faraday cage containing the developer in an airflow after the toner had been blown off.The total charge collected in the cage is divided by the mass of toner removed by the blow-off, by weighing the cage before and after the blow-off, so that the Q / m ratio is obtained. The toner from Example 2 was tested, and the charge results obtained were acceptable – comparable to results for a nominal ULM toner used as a control. Furthermore, the toner charge properties can be optimized, with improvements to both Q / m and Q / d being achieved by adjusting the toner envelope thickness, varying the weight percentage of crystalline material, incorporating both low-molecular-weight crystalline imides and a crystalline polymer, optimizing the ratio, and adjusting the toner agglomeration / fusion process, e.g., by adjusting the fusion temperature. It is understood that variants of the above-disclosed properties and functions, as well as other properties and functions or alternatives thereof, can be combined to form further different systems or applications. Numerous currently unforeseen or unaccepted alternatives, modifications, variations, or improvements hereto can subsequently be implemented by the person skilled in the art, which is also intended by the following claims.

Claims

Toner comprising: a polymer resin, wherein the polymer resin is an unsaturated amorphous polyester resin; optionally a colorant; and a low molecular weight crystalline imide having a molecular mass of less than 1,000 g / mol, wherein the low molecular weight crystalline imide is N-benzylphthalimide of the following formula: Toner according to claim 1, further comprising a crystalline polymer resin. Toner according to claim 1, wherein a mixture of the amorphous polymer resin and the low molecular weight crystalline imide is characterized by a reduction in the glass transition temperature of the amorphous polymer resin and by the absence of a significant solid-to-liquid phase transition peak of the low molecular weight crystalline imide, as determined by differential dynamic calorimetry, wherein the fixation enthalpy for the low molecular weight crystalline imide in the mixture measures less than 10% of the fixation enthalpy of the low molecular weight crystalline imide in pure form. Emulsion aggregation toner comprising: an amorphous polymer resin, wherein the polymer resin is an unsaturated amorphous polyester resin; optionally a colorant; and a low molecular weight crystalline imide having a molecular mass of less than 500 g / mol and a melting point below 120 °C, wherein the low molecular weight crystalline imide is N-benzylphthalimide of the following formula: wherein a mixture of the amorphous polymer resin and the low molecular weight crystalline imide is characterized by a reduction in the glass transition temperature of the amorphous polymer resin and by the absence of a significant solid-to-liquid phase transition peak for the low molecular weight crystalline imide, as determined by differential dynamic calorimetry, wherein the fixation enthalpy for the low molecular weight crystalline imide in the mixture measures less than 10% of the fixation enthalpy of the low molecular weight crystalline imide in pure form.

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