JP5800782B2 - Toner for electrostatic latent image development - Google Patents

Description

  The present invention relates to an electrostatic latent image developing toner.

  In general, in electrophotography, the surface of a photosensitive drum is charged using corona discharge or the like, and then exposed to light using a laser or the like. Is used to develop a toner image. Further, the formed toner image is transferred to a recording medium, and a high quality image is obtained. Usually, a toner used for forming a toner image is obtained by mixing components such as a colorant, a charge control agent, a release agent, and a magnetic material into a binder resin such as a thermoplastic resin, and then kneading, pulverizing, Toner particles (toner base particles) having an average particle diameter of 5 μm or more and 10 μm or less obtained through a classification step are used. For the purpose of imparting fluidity to the toner, imparting suitable charging performance to the toner, and facilitating cleaning of the toner from the surface of the photosensitive drum, an inorganic fine powder such as silica or titanium oxide is used. Externally added to the base particles.

  With respect to such a toner, from the viewpoint of energy saving and apparatus miniaturization, a toner having excellent low-temperature fixability that can be fixed satisfactorily without heating the fixing roller as much as possible is desired. However, toners excellent in low-temperature fixability often use a binder resin having a low melting point or glass transition point or a low melting point release agent. For this reason, toners with excellent low-temperature fixability generally tend to agglomerate when the toner is stored at a high temperature, or the recording medium on which the toner image is fixed is wound around a fixing roller (hereinafter referred to simply as winding). There is a problem that is likely to occur.

  Therefore, in order to obtain a toner that suppresses the occurrence of winding and has excellent low-temperature fixability, the interfacial adhesion force (Fr) between the toner and polytetrafluoroethylene, which is measured using a specific measurement method, is 1. There has been proposed a toner having an internal cohesive force (Ft) of 10 N or more and 18 N or less, which is similarly measured using a specific measurement method (see Patent Document 1). .

JP 2006-330706 A

  However, although the toner obtained by using the method described in Patent Document 1 suppresses the occurrence of winding and is excellent in low-temperature fixability, the temperature range in which the toner image can be satisfactorily fixed on the recording medium is narrow. There's a problem.

  The present invention has been made in view of the above circumstances, and is an electrostatic latent image developing toner that has excellent low-temperature fixability, is well fixed in a wide temperature range, and can suppress winding of a recording medium around a fixing roller. The purpose is to provide.

  The inventors of the present invention have an internal cohesive force (F) of 5N or more and 10N or less, measured using a specific method, for a toner for developing an electrostatic latent image containing a binder resin and a release agent. The inventors have found that the above problems can be solved by the electrostatic latent image developing toner having an interface adhesion force (f) of 0.5 N or more and 1 N or less, and have completed the present invention. Specifically, the present invention provides the following.

The present invention is an electrostatic latent image developing toner comprising a binder resin and a release agent,
The electrostatic latent image developing toner has an internal cohesion force (F) of 5 N or more and 10 N or less, and an interface adhesion force (f) of 0.5 N or more and 1 N or less,
The internal cohesive force (F) is
A sample stage S ₁ consisting of an aluminum plate having a thickness of 3mm, which heater H _S is attached to the lower surface,
Comprising a heater H _P, and a load cell attached to an upper surface of the heater H _P, attached to the lower surface of the heater H _P, a cylindrical indenter under an aluminum bottom are coated with a polyimide resin film, the said above the sample stage S _1, the pressure portion P ₁ which is disposed movably in a direction perpendicular to the surface direction of the sample stage S _1,
Using a measuring device _{M F} comprise the following step I) to III):
Step I) and the heating member _{H S,} with the heating member _{H P,} the pressing _{P 1} and the sample stage _{S 1,} is heated to respectively 0.99 ° C.,
II) The temperature of the pressure part P ₁ and the sample stage S ₁ is maintained at 150 ° C., and a toner sample is placed on the sample stage S ₁ so as to be 1.0 g / cm ^2. A step of pressurizing the toner sample for 30 seconds at a pressure of 10 N / cm ² using the pressure portion P ₁ , and III) after pressurization, the pressure portion P ₁ is raised at a speed of 60 mm / second to apply pressure step of measuring from pressure start to the pressing P ₁ is raised 10 cm, measured using the load cell, the maximum value of the load applied between the pressing P ₁ and the sample stage S ₁ ,
Measured using a method comprising
The interface adhesion force (f) is:
Wherein said sample stage _{S 1} of the measuring device _{M F,} and the heater _{H S} is attached to the lower surface, the surface of an aluminum plate having a thickness of 3 mm, thickness 25.3Myuemu, roughness (Ra) is 0. 30μm of PFA resin (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) is retrofit sample stage _{S 2} made of PFA-coated aluminum plate was coated by using a measuring device _{M f,} the step I) to III ) Measured using a method comprising
The present invention relates to an electrostatic latent image developing toner.

  According to the present invention, it is possible to provide an electrostatic latent image developing toner that is excellent in low-temperature fixability, is well fixed in a wide temperature range, and can suppress winding of a recording medium around a fixing roller.

It is a schematic diagram showing a measuring device M _F for measuring internal cohesive force (F). It is a schematic diagram which shows the measuring apparatus _Mf for measuring interface adhesive force (f).

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention. . In addition, although description may be abbreviate | omitted suitably about the location where description overlaps, the summary of invention is not limited.

  The electrostatic latent image developing toner of the present invention (hereinafter also simply referred to as toner) is an electrostatic latent image developing toner containing a binder resin and a release agent, and measured using a specific method. The internal cohesion force (F) is 5N or more and 10N or less, and the interface adhesion force (f) is 0.5N or more and 1N or less. Hereinafter, the toner of the present invention, the internal cohesive force (F), and the interfacial adhesion force (f) will be described.

<Electrostatic latent image developing toner>
The toner of the present invention may contain a colorant, a release agent, and a charge control agent, if desired, in addition to the binder resin and the release agent. Further, the toner of the present invention may be one having an external additive attached to the surface thereof, if necessary. Further, the toner of the present invention can be mixed with a desired carrier and used as a two-component developer. Hereinafter, the binder resin, the release agent, the colorant, the charge control agent, the magnetic powder, and the external additive which are essential or optional components for the toner of the present invention, and the toner of the present invention as a two-component developer. The carrier used in the case of using the toner and the method for producing the toner of the present invention will be described in order.

[Binder resin]
The binder resin contained in the toner of the present invention is not particularly limited as long as it is a resin conventionally used as a binder resin for toner. Specific examples of the binder resin include styrene resin, acrylic resin, styrene acrylic resin, polyethylene resin, polypropylene resin, vinyl chloride resin, polyester resin, polyamide resin, polyurethane resin, polyvinyl alcohol resin, vinyl ether. And thermoplastic resins such as styrene resins, N-vinyl resins, and styrene-butadiene resins. Among these resins, a styrene acrylic resin and a polyester resin are preferable, and a polyester resin is more preferable from the viewpoints of dispersibility of the colorant in the toner, toner chargeability, and paper fixing property. Hereinafter, the styrene acrylic resin and the polyester resin used in this embodiment will be described.

  The styrene acrylic resin is a copolymer of a styrene monomer and an acrylic monomer. Specific examples of the styrene monomer include styrene, α-methylstyrene, vinyl toluene, α-chlorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, and p-ethylstyrene. Specific examples of the acrylic monomer include methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, 2-ethylhexyl acrylate, meta Examples include (meth) acrylic acid alkyl esters such as methyl acrylate, ethyl methacrylate, n-butyl methacrylate, and iso-butyl methacrylate.

  When a polyester resin is used as the binder resin, it is easy to prepare a toner that can be satisfactorily fixed over a wide temperature range and has excellent color developability. As the polyester resin, those obtained by condensation polymerization or co-condensation polymerization of a divalent or trivalent or higher alcohol component and a divalent or trivalent or higher carboxylic acid component can be used. The components used when synthesizing the polyester resin include the following alcohol components and carboxylic acid components.

  Specific examples of the divalent or trivalent or higher alcohol component include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1 Diols such as 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol; bisphenol A Bisphenols such as hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A; sorbitol, 1,2,3,6-hexanetetrol, 1,4-sol Tan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2, Examples include trivalent or higher alcohols such as 4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene.

  Specific examples of the divalent or trivalent or higher carboxylic acid component include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, Sebacic acid, azelaic acid, malonic acid, or n-butyl succinic acid, n-butenyl succinic acid, isobutyl succinic acid, isobutenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid Divalent carboxylic acids such as acids, isododecyl succinic acid, alkyl such as isododecenyl succinic acid or alkenyl succinic acid; 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5- Benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4 Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid , A trivalent or higher carboxylic acid such as tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, and empole trimer acid. As these divalent or trivalent or higher carboxylic acid components, acid halides, acid anhydrides, and ester-forming derivatives of lower alkyl esters may be used. Here, “lower alkyl” means an alkyl group having 1 to 6 carbon atoms.

  When the binder resin is a polyester resin, the acid value of the polyester resin is preferably 10 mgKOH / g or more and 40 mgKOH / g or less. If the acid value is too low, when the toner is prepared by the aggregation method described later, when the fine particles of the components contained in the toner are aggregated, the aggregation of the fine particles may not proceed well. If it is too high, various performances of the toner may be impaired due to the influence of humidity under high humidity conditions. The acid value of the polyester resin can be adjusted by adjusting the balance between the hydroxyl group of the alcohol component used for the synthesis of the polyester resin and the carboxyl group of the carboxylic acid component.

  As the binder resin, not only a thermoplastic resin can be used alone, but also a resin obtained by adding a crosslinking agent or a thermosetting resin to the thermoplastic resin can be used. By introducing a partially crosslinked structure into the binder resin, the storage stability, shape retention, and durability of the toner can be improved without deteriorating the toner fixability.

  As the thermosetting resin that can be used together with the thermoplastic resin, an epoxy resin or a cyanate resin is preferable. Specific examples of suitable thermosetting resins include bisphenol A type epoxy resins, hydrogenated bisphenol A type epoxy resins, novolac type epoxy resins, polyalkylene ether type epoxy resins, cycloaliphatic type epoxy resins, and cyanate resins. . These thermosetting resins can be used in combination of two or more.

  The glass transition point (Tg) of the binder resin is preferably 50 ° C. or higher and 70 ° C. or lower. If the glass transition point of the binder resin is too low, the toner may be fused inside the developing part of the image forming apparatus, or the storage stability of the toner may be reduced. Some of them may be fused together. On the other hand, if the glass transition point of the binder resin is too low, the strength of the polyester resin is reduced, and the toner tends to adhere to the latent image carrying portion. If the glass transition point of the binder resin is too high, the toner tends to be difficult to fix well at low temperatures.

  In addition, the glass transition point of binder resin can be calculated | required from the change point of specific heat of binder resin using a differential scanning calorimeter (DSC) based on JISK7121. A more specific measuring method is as follows. It can obtain | require by measuring the endothermic curve of binder resin using the differential scanning calorimeter DSC-6200 by Seiko Instruments Inc. as a measuring apparatus. 10 mg of a measurement sample is put in an aluminum pan, and an empty aluminum pan is used as a reference. Obtaining the glass transition point of the binder resin using the endothermic curve of the binder resin obtained by measurement under the conditions of a measurement temperature range of 25 ° C. or more and 200 ° C. or less, a heating rate of 10 ° C./min, and normal temperature and normal humidity. Can do.

  The melting point (Tm) of the binder resin is preferably 80 ° C. or higher and 120 ° C. or lower. If the melting point of the binder resin is too high, it may be difficult to fix the toner well at a low temperature. If the melting point of the binder resin is too low, the toner may agglomerate during storage at a high temperature, and the heat resistant storage stability of the toner may be impaired.

  The number average molecular weight (Mn) of the binder resin is not particularly limited as long as it does not impair the object of the present invention, but is preferably 1,500 or more and 3,000 or less. The mass average molecular weight (Mw) of the binder resin is not particularly limited as long as it does not impair the object of the present invention, but is preferably 1,500 or more and 11,000 or less, and more preferably 3,500 or more and 6,500 or less. . When the number average molecular weight (Mn) and the mass average molecular weight (Mw) are too small, the internal cohesion force (F) of the toner, which is measured using a measurement method described later, tends to be less than 5.0N. On the other hand, when the number average molecular weight (Mn) and the mass average molecular weight (Mw) are excessive, the internal cohesion force (F) of the toner, which is measured using a measurement method described later, tends to exceed 1.0 N.

  Further, the molecular weight distribution (Mw / Mn) represented by the ratio of the number average molecular weight (Mn) to the mass average molecular weight (Mw) is preferably 2 or more and 10 or less. By setting the molecular weight distribution of the binder resin within such a range, it becomes easy to obtain a toner having excellent low-temperature fixability. The number average molecular weight (Mn) and the mass average molecular weight (Mw) of the binder resin can be measured using gel permeation chromatography.

When a polyester resin is used as the binder resin, the content of the oligomer so that the amount of the oligomer having a molecular weight of 1000 or less based on the mass of the toner in the toner measured by a predetermined method is 1000 ppm by mass or less. A polyester resin that has been subjected to a treatment for reducing the viscosity is preferred.
In the claims and specification of the present application, a polyester resin that has been subjected to a treatment for removing at least a part of oligomers contained in the polyester resin or a treatment for reducing the amount of oligomers produced in the synthesis step is used. This is referred to as “low oligomer polyester resin”.

  The amount of the oligomer having a molecular weight of 1000 or less contained in the polyester resin is adjusted so that the amount of the oligomer having a molecular weight of 1000 or less in the toner based on the mass of the toner is 1000 ppm by mass or less.

<Measurement method of oligomer content in toner (methanol extraction method)>
The content Y (mass ppm) of the oligomer having a molecular weight of 1000 or less derived from the binder resin in the toner is:
The following steps (1) to (3):
(1) A step of obtaining a methanol extract containing a binder resin-derived oligomer by stirring 100 g of a sample of electrostatic latent image developing toner in 500 g of methanol at 60 ° C. for 8 hours;
(2) Among oligomers contained in the methanol extract, the content of the oligomer having a molecular weight of 1000 or less in the methanol extract is measured, and the mass X (g) of the oligomer having a molecular weight of 1000 or less contained in the total amount of the methanol extract. And (3) the following formula:
Y = (X / 100) × 1000000,
A step of calculating a content Y (mass ppm) of an oligomer having a molecular weight of 1000 or less in the toner, based on the mass of the toner,
Can be measured.

  The method for measuring the amount of oligomer having a molecular weight of 1000 or less among the oligomers contained in the methanol extract is not particularly limited. The amount of the oligomer having a molecular weight of 1000 or less contained in the methanol extract is determined by infrared spectroscopy (IR), ultraviolet spectroscopy, nuclear magnetic resonance spectroscopy (NMR), high performance liquid chromatography (HPLC), gel permeation chromatography ( GPC) and mass spectrometry can be used for analysis. Especially, it is preferable to measure the quantity of the oligomer of molecular weight 1000 or less using GPC. Hereinafter, a method for measuring the amount of oligomer having a molecular weight of 1000 or less using GPC will be described.

(Measurement method of oligomer amount with molecular weight of 1000 or less using GPC)
Tetrahydrofuran (THF) is used as a solvent, and a sample to be measured is dissolved in THF at a concentration of preferably 0.1 mg / ml to 5 mg / ml, more preferably 0.5 mg / ml to 2 mg / ml. As a method for dissolving the sample in THF, there are a method of stirring the sample in THF and a method of immersing the sample in THF in an ultrasonic bath. Thereafter, the obtained THF solution is filtered with a sample processing filter to obtain a measurement sample used for GPC measurement. The GPC is measured by stabilizing the column at 40 ° C. and flowing a THF solution at a flow rate of 0.35 ml / min under the temperature condition. The molecular weight distribution of the sample is measured as a styrene equivalent molecular weight using a calibration curve prepared using several types of monodisperse polystyrene. It is preferable to measure at least 10 points in order to increase the accuracy of the calibration curve. As the detector, an RI (refractive index) detector or a UV (ultraviolet) detector can be used, but it is preferable to use an RI detector in that detection is possible regardless of the composition of the sample. As a column, a standard polystyrene gel column can be used in combination.

GPC of monodisperse standard polystyrene having a number average molecular weight of 1000 is measured to determine the retention capacity (ml) at the peak position, and this is defined as RVS. GPC of the residue obtained by distilling off the methanol component from the methanol extract is measured and calculated as the ratio of the area of the low molecular side peak portion below RVS to the area of the entire peak of the GPC chromatogram. At this time, a differential refractometer is usually used as the detector. However, only the oligomer portion is separately collected by preparative liquid chromatography, and the monomer composition is pyrolyzed by gas chromatography, infrared spectrometer and proton nucleus. Check with a magnetic resonance measuring device. At this time, when the composition of the entire copolymer is exactly the same, the peak area ratio can be expressed as a weight ratio on the assumption that there is no difference in the refractive index between the oligomer portion and the entire copolymer. The amount of oligomer having a molecular weight of 1000 or less is obtained by calculating the ratio of the peak area of the chromatogram as a percentage.
<GPC measurement conditions>
Apparatus: HLC-8320 (manufactured by Tosoh Corporation)
Eluent: THF (tetrahydrofuran)
Column: TSKgel SuperMultipore HZ-M (manufactured by Tosoh Corporation)
Number of columns: 3 detectors: RI
Eluent flow rate: 0.35 ml / min Sample concentration: 2.0 g / liter Column temperature: 40 ° C.
Sample volume: 10 microliters Sample preparation: Adjusted with eluent, shaken for 1 hour using a shaker, filtered using a filter (pore size 5 microns): Prepared using standard polystyrene

  When the polyester resin is a resin synthesized using a monomer containing an aromatic ring such as polyoxyethylenated bisphenol A and polyoxypropylenated bisphenol A, the content of oligomers having a predetermined molecular weight or less in methanol As a method for measuring, a method using high performance liquid chromatography equipped with a UV detector is preferable.

〔Release agent〕
The toner for developing an electrostatic latent image of the present invention contains a release agent for the purpose of improving the fixability and offset resistance. The type of release agent is not particularly limited as long as it is conventionally used as a release agent for toner.

  Suitable mold release agents include low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymers, polyolefin waxes, microcrystalline waxes, paraffin waxes, and aliphatic hydrocarbon waxes such as Fischer-Tropsch wax; oxidized polyethylene waxes, and Oxides of aliphatic hydrocarbon waxes such as block copolymers of oxidized polyethylene waxes; plant waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax, and rice wax; beeswax, lanolin, and whale Animal waxes such as waxes; mineral waxes such as ozokerite, ceresin, and vetrolactam; waxes based on fatty acid esters such as montanate ester wax and castor wax; Some fatty acid esters such as acid carnauba wax, or wax deoxidizing the like all.

  Suitable release agents further include saturated linear fatty acids such as palmitic acid, stearic acid, montanic acid, and long-chain alkyl carboxylic acids having a long-chain alkyl group; brassic acid, eleostearic acid And unsaturated fatty acids such as valinalic acid; saturated alcohols such as stearyl alcohol, eicosyl alcohol, behenyl alcohol, carnauvyl alcohol, seryl alcohol, melyl alcohol, and long chain alkyl alcohols having long chain alkyl groups Polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis lauric acid amide, and hexamethylene vinyl Saturated fatty acid bisamides such as stearic acid amides; Unsaturated fatty acids such as ethylene bisoleic acid amides, hexamethylene bisoleic acid amides, N, N′-dioleyl adipic acid amides, N, N′-dioleyl sebacic acid amides Aromatic bisamides such as amides, m-xylene bis-stearic amide, and N, N′-distearylisophthalic amide; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate, and magnesium stearate A wax obtained by grafting a vinyl monomer such as styrene or acrylic acid to an aliphatic hydrocarbon wax; a partially esterified product of a fatty acid such as behenic monoglyceride and a polyhydric alcohol; hydrogenating vegetable oils and fats; Hydro obtained by And methyl ester compounds having a sill group.

  The amount of the release agent used is not particularly limited as long as the object of the present invention is not impaired. Specifically, the amount of the release agent used is preferably 8% by mass or more and 20% by mass or less, and more preferably 10% by mass or more and 15% by mass or less with respect to the mass of the toner. When the amount of the release agent used is too small, a desired effect may not be obtained with respect to suppression of occurrence of offset and image smearing in the formed image. When the amount of the release agent used is too small, the interfacial adhesion force (f) of the toner, which is measured using a measurement method described later, tends to exceed 1.0 N. On the other hand, when the amount of the release agent used is excessive, the storage stability of the toner may be reduced due to fusion between the toners.

[Colorant]
As the colorant contained in the toner for developing an electrostatic latent image of the present invention, a known pigment or dye can be used according to the color of the toner particles. Specific examples of suitable colorants that can be added to the toner include the following colorants.

  Examples of the black colorant include carbon black. Specifically, Raven 1060, 1080, 1170, 1200, 1250, 1255, 1500, 2000, 3500, 5250, 5750, 7000, 5000, ULTRAII, 1190 ULTRAII, manufactured by Columbian Carbon; Black PearlsL, Moguul, manufactured by Cabot -L, Regal 400R, 660R, 330R, Monarch 800, 880, 900, 1000, 1300, 1400; Color Black FW1, FW2, FW200, 18, S160, S170, Special Black 4, 4A, 6, Printex35, U manufactured by Degussa 140U, V, 140V; No. manufactured by Mitsubishi Chemical Corporation. 25, 33, 40, 47, 52, 900, 2300, MCF-88, MA600, 7, 8, 100. Further, as the black colorant, a colorant that is toned to black using a colorant such as a yellow colorant, a magenta colorant, and a cyan colorant, which will be described later, can also be used. Examples of the color toner colorant include a yellow colorant, a magenta colorant, and a cyan colorant.

  Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 191 and 194.

  Examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 19, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221 and 254.

  Examples of cyan colorants include copper phthalocyanine compounds, copper phthalocyanine derivatives, anthraquinone compounds, and basic dye lake compounds. Specifically, C.I. I. Pigment blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66.

  These colorants can be used alone or in combination. The amount of the colorant used is not particularly limited as long as the object of the present invention is not impaired. Specifically, it is preferably 3% by mass or more and 15% by mass or less based on the mass of the toner.

(Charge control agent)
The electrostatic latent image developing toner of the present invention may contain a charge control agent as required. The charge control agent improves the stability of the charge level of the toner and the charge rise characteristic that is an indicator of whether the toner can be charged to a predetermined charge level in a short time. Used for gaining purposes. When developing with positively charged toner, a positively chargeable charge control agent is used. When developing with negatively charged toner, a negatively chargeable charge control agent is used.

  The type of the charge control agent is not particularly limited as long as the object of the present invention is not impaired, and can be appropriately selected from charge control agents conventionally used in toners. Specific examples of the positively chargeable charge control agent include pyridazine, pyrimidine, pyrazine, orthooxazine, metaoxazine, paraoxazine, orthothiazine, metathiazine, parathiazine, 1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, 1,2,4-oxadiazine, 1,3,4-oxadiazine, 1,2,6-oxadiazine, 1,3,4-thiadiazine, 1,3,5-thiadiazine, 1, 2,3,4-tetrazine, 1,2,4,5-tetrazine, 1,2,3,5-tetrazine, 1,2,4,6-oxatriazine, 1,3,4,5-oxatriazine, Azine compounds such as phthalazine, quinazoline and quinoxaline; Azin Fast Red FC, Azin Fast Red 12BK, Azine Violet BO, Azine Direct dyes composed of azine compounds such as N-Brown 3G, Azin Light Brown GR, Azin Dark Green BH / C, Azin Deep Black EW, and Azin Deep Black 3RL; Nigrosine such as Nigrosine, Nigrosine Salt, Nigrosine Derivative Compounds; Acid dyes consisting of nigrosine compounds such as nigrosine BK, nigrosine NB, nigrosine Z; metal salts of naphthenic acid or higher fatty acids; alkoxylated amines; alkylamides; 4 such as benzylmethylhexyldecylammonium and decyltrimethylammonium chloride A class ammonium salt is mentioned. Among these positively chargeable charge control agents, a nigrosine compound is particularly preferable in that a more rapid start-up property can be obtained. These positively chargeable charge control agents can be used in combination of two or more.

  A resin having a quaternary ammonium salt, carboxylate, or carboxyl group as a functional group can also be used as a positively chargeable charge control agent. More specifically, a styrene resin having a quaternary ammonium salt, an acrylic resin having a quaternary ammonium salt, a styrene acrylic resin having a quaternary ammonium salt, a polyester resin having a quaternary ammonium salt, and a carboxylate Styrene resin having carboxylate, acrylic resin having carboxylate, styrene acrylic resin having carboxylate, polyester resin having carboxylate, styrene resin having carboxyl group, acrylic resin having carboxyl group, carboxyl group Styrene acrylic resin having a carboxyl group and polyester resin having a carboxyl group. The molecular weight of these resins is not particularly limited as long as the object of the present invention is not impaired, and may be an oligomer or a polymer.

  Among the resins that can be used as positively chargeable charge control agents, styrene acrylic resins having a quaternary ammonium salt as a functional group are more preferable because the charge amount can be easily adjusted to a value within a desired range. preferable. Specific examples of preferred acrylic comonomers that are copolymerized with styrene units in styrene acrylic resins having a quaternary ammonium salt as a functional group include methyl acrylate, ethyl acrylate, n-propyl acrylate, and iso-propyl acrylate. (Meth) acrylic acid, such as n-butyl acrylate, iso-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate Examples include alkyl esters.

  As the quaternary ammonium salt, a unit derived from a dialkylaminoalkyl (meth) acrylate, dialkylamino (meth) acrylamide, or dialkylaminoalkyl (meth) acrylamide through a quaternization step is used. Specific examples of the dialkylaminoalkyl (meth) acrylate include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, and dibutylaminoethyl (meth) acrylate. A specific example of dialkyl (meth) acrylamide is dimethylmethacrylamide. Specific examples of the dialkylaminoalkyl (meth) acrylamide include dimethylaminopropyl methacrylamide. Further, a hydroxy group-containing polymerizable monomer such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, or N-methylol (meth) acrylamide can be used in combination during polymerization.

  Specific examples of the negatively chargeable charge control agent include organometallic complexes and chelate compounds. Examples of organometallic complexes and chelate compounds include acetylacetone metal complexes such as aluminum acetylacetonate and iron (II) acetylacetonate, and salicylic acid metal complexes such as chromium 3,5-di-tert-butylsalicylate. A salicylic acid metal salt is preferable, and a salicylic acid metal complex or a salicylic acid metal salt is more preferable. These negatively chargeable charge control agents can be used in combination of two or more.

  The amount of the positively or negatively chargeable charge control agent used is not particularly limited as long as the object of the present invention is not impaired. The use amount of the positively or negatively chargeable charge control agent is typically 1.5 parts by mass or more and 15 parts by mass or less, preferably 2.0 parts by mass when the total amount of the toner is 100 parts by mass. The amount is more preferably 8.0 parts by mass or less, and particularly preferably 3.0 parts by mass or more and 7.0 parts by mass or less. When the amount of charge control agent used is too small, it is difficult to stably charge the toner to a predetermined polarity, so that the image density of the formed image falls below a desired value, or it is difficult to maintain the image density over a long period of time. There are things to do. In such a case, the charge control agent is difficult to uniformly disperse in the toner, so that the formed image is likely to be fogged or the latent image carrier is easily contaminated by the toner component. If the amount of charge control agent used is excessive, image defects in the formed image due to poor charging under high temperature and high humidity due to deterioration in environmental resistance, and contamination by toner components in the latent image carrier may occur. It becomes easy.

[Magnetic powder]
The electrostatic latent image developing toner of the present invention can be blended with magnetic powder as desired. The kind of magnetic powder is not particularly limited as long as the object of the present invention is not impaired. Examples of suitable magnetic powders include irons such as ferrite and magnetite; ferromagnetic metals such as cobalt and nickel; alloys containing iron and / or ferromagnetic metals; compounds containing iron and / or ferromagnetic metals A ferromagnetic alloy subjected to a ferromagnetization treatment such as heat treatment; chromium dioxide.

  The particle size of the magnetic powder is not limited as long as the object of the present invention is not impaired. Specifically, the particle size of the magnetic powder is preferably 0.1 μm or more and 1.0 μm, and more preferably 0.1 μm or more and 0.5 μm or less. When magnetic powder having a particle diameter in such a range is used, it is easy to uniformly disperse the magnetic powder in the binder resin.

  As the magnetic powder, for the purpose of improving the dispersibility in the toner, a powder that has been surface-treated with a surface treatment agent such as a titanium coupling agent or a silane coupling agent can be used.

  The usage-amount of magnetic powder is not specifically limited in the range which does not inhibit the objective of this invention. The specific amount of magnetic powder used is preferably 35 parts by weight or more and 60 parts by weight or less, and 40 parts by weight or more and 60 parts by weight or less when the toner is used as a one-component developer and the total amount of toner is 100 parts by weight. The following is more preferable. If the amount of magnetic powder used is excessive, it may be difficult to maintain the image density at a desired value over a long period of time, or the toner fixability may be extremely reduced. If the amount of magnetic powder used is too small, fog may easily occur in the formed image, or it may be difficult to form an image having a desired image density over a long period of time. When the toner is used as a two-component developer, the amount of magnetic powder used is preferably 20% by mass or less and more preferably 15% by mass or less when the total amount of toner is 100 parts by mass.

(External additive)
The surface of the electrostatic latent image developing toner obtained by using the method of the present invention may be treated with an external additive as desired. The type of external additive that can be used in the toner of the present invention is not particularly limited as long as it does not impair the object of the present invention, and can be appropriately selected from external additives that have been conventionally used for toners. Specific examples of suitable external additives include silica and metal oxides such as alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, and barium titanate. These external additives can be used in combination of two or more. Further, these external additives can be used after being hydrophobized using a hydrophobizing agent such as an aminosilane coupling agent or silicone oil. In the case of using a hydrophobized external additive, it is easy to suppress a decrease in charge amount of the toner under high temperature and high humidity, and it is easy to obtain a toner excellent in fluidity.

  The particle diameter of the external additive is not particularly limited as long as it does not impair the object of the present invention, and typically 0.01 μm or more and 1.0 μm or less is preferable.

  The amount of the external additive used is not particularly limited as long as the object of the present invention is not impaired. Typically, the amount of the external additive used is preferably 0.1 parts by weight or more and 10 parts by weight or less, more preferably 0.2 parts by weight or more with respect to 100 parts by weight of the toner particles (toner base particles) before the external addition treatment. 5 parts by mass or less is more preferable.

[Carrier]
The electrostatic latent image developing toner obtained by using the method of the present invention can be mixed with a desired carrier and used as a two-component developer. When preparing a two-component developer, it is preferable to use a magnetic carrier.

  Suitable carriers when the toner for developing an electrostatic latent image of the present invention is a two-component developer include those in which a carrier core material is coated with a resin. Specific examples of the carrier core material include particles such as iron, oxidized iron, reduced iron, magnetite, copper, silicon steel, ferrite, nickel, and cobalt, and particles of alloys of these materials with manganese, zinc, and aluminum. , Particles like iron-nickel alloy, iron-cobalt alloy, titanium oxide, aluminum oxide, copper oxide, magnesium oxide, lead oxide, zirconium oxide, silicon carbide, magnesium titanate, barium titanate, lithium titanate, titanate Ceramic particles such as lead, lead zirconate and lithium niobate, particles of high dielectric constant materials such as ammonium dihydrogen phosphate, potassium dihydrogen phosphate and Rochelle salt, and the above magnetic particles dispersed in resin A resin carrier is mentioned.

  Specific examples of the resin covering the carrier core material include (meth) acrylic polymer, styrene polymer, styrene- (meth) acrylic copolymer, olefin polymer (polyethylene, chlorinated polyethylene, polypropylene). , Polyvinyl chloride, polyvinyl acetate, polycarbonate, cellulose resin, polyester resin, unsaturated polyester resin, polyamide resin, polyurethane resin, epoxy resin, silicone resin, fluororesin (polytetrafluoroethylene, polychlorotrifluoroethylene, polyfluoride) Vinylidene), phenol resin, xylene resin, diallyl phthalate resin, polyacetal resin, and amino resin. These resins can be used in combination of two or more.

  The particle size of the carrier is not particularly limited as long as the object of the present invention is not impaired, but the particle size measured using an electron microscope is preferably 20 μm or more and 120 μm or less, and more preferably 25 μm or more and 80 μm or less.

  When the toner produced using the method of the present invention is used as a two-component developer, the toner content in the two-component developer is 3% by mass or more and 20% by mass or less based on the mass of the two-component developer. Is preferably 5% by mass or more and 15% by mass or less. By setting the toner content in the two-component developer in such a range, it is easy to maintain the image density of the formed image at an appropriate level, and the toner contamination inside the image forming apparatus is suppressed by suppressing the toner scattering from the developing apparatus. And toner adhesion to the transfer paper can be suppressed.

[Method for producing toner for developing electrostatic latent image]
The method for producing the toner for developing an electrostatic latent image is not particularly limited as long as a toner in which the internal cohesive force (F) and the interfacial adhesion force (f) of the toner are in a predetermined range can be obtained. Suitable methods for producing the toner of the present invention include a melt-kneading method and an aggregating method.

  In the melt-kneading method, a binder resin and a release agent are mixed with optional components such as a colorant, a charge control agent, and magnetic powder, and then the mixture is melt-kneaded, and the resulting melt-kneaded product is pulverized. In this method, core particles having a desired particle diameter are obtained by classification.

  In the aggregation method, the fine particles containing the binder resin and the fine particles containing the release agent are aggregated in an aqueous medium, or the fine particles containing the binder resin and the release agent are aggregated in an aqueous medium, After obtaining an aqueous medium dispersion containing an aggregate of fine particles containing a binder resin and a release agent, the aqueous medium dispersion containing the obtained aggregate of fine particles is heated to obtain a desired particle size whose shape is controlled. This is a method for obtaining toner particles.

  Among these toner particle production methods, the coagulation method is preferred because it is easy to obtain toner particles having a uniform shape and a toner with little variation in internal cohesive force (F) and interfacial adhesion force (f). . Hereinafter, the aggregation method will be described in detail.

  Regarding the agglomeration method, steps of (i) fine particle preparation step, (ii) fine particle aggregation step, and (iii) fine particle coalescence step will be described in order.

[Step (i): Fine particle preparation step]
The method for preparing the fine particles is not particularly limited. For the fine particles of the binder resin, the fine particles of the release agent, and the fine particles containing the binder resin and the release agent, these components or a composition containing these components is desirable. It is preferable to prepare as an aqueous medium dispersion containing fine particles finely divided to a size of 5 mm. Further, in the after-mentioned (ii) fine particle agglomeration step, coloring is performed with the fine particles of the binder resin and the release agent, or with the fine particles containing the binder resin and the release agent, as necessary. It is also preferable to use fine particles of the agent. Hereinafter, a method for preparing fine particles including a binder resin, a method for preparing fine particles including a release agent, a method for preparing fine particles including a binder resin and a release agent, and a method for preparing colorant fine particles will be described.

(Method for preparing fine particles containing binder resin)
Hereinafter, a preferred example of the method for preparing the binder resin fine particles will be described. The method of preparing the binder resin fine particles is not limited to the method described below.

  First, the binder resin is heated to a temperature equal to or higher than its melting point to obtain a binder resin melt. The temperature at which the binder resin is melted is not particularly limited as long as the binder resin is uniformly melted, but a temperature of the melting point of the binder resin + 10 ° C. to the melting point + 30 ° C. is preferable.

  When a polyester resin is used as the binder resin, a basic substance may be added to the molten binder resin in order to neutralize the acid groups contained in the polyester resin. The basic substance is not particularly limited as long as it can neutralize acid groups contained in the polyester resin and does not impair the object of the present invention. Suitable basic materials include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide, alkali metal carbonates such as sodium carbonate, and potassium carbonate, sodium bicarbonate, and hydrogen carbonate. Alkali metal hydrogen carbonate such as potassium, N, N-dimethylethanolamine, N, N-diethylethanolamine, triethanolamine, tripropanolamine, tributanolamine, triethylamine, n-propylamine, n-butylamine, isopropyl Examples thereof include nitrogen-containing organic bases such as amine, monomethanolamine, morpholine, methoxypropylamine, pyridine, and vinylpyridine. These basic compounds may be used individually by 1 type, and may be used in combination of 2 or more types.

  The usage-amount of a basic compound is not specifically limited in the range which does not inhibit the objective of this invention, and is suitably determined in consideration of the acid value of a polyester resin. Typically, the amount of the basic compound used is preferably 1 part by mass or more and 20 parts by mass or less, and more preferably 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the binder resin.

  Further, a surfactant can be added to the binder resin melt. When a surfactant is added to the binder resin melt, fine particles of the binder resin can be stably dispersed in an aqueous medium.

  The surfactant that can be added to the binder resin melt is not particularly limited, and can be appropriately selected from the group consisting of an anionic surfactant, a cationic surfactant, and a nonionic surfactant. Examples of anionic surfactants include sulfate ester type surfactants, sulfonate type surfactants, phosphate ester type surfactants, and soaps. Examples of the cationic surfactant include an amine salt type activator and a quaternary ammonium salt type activator. Examples of nonionic surfactants include polyethylene glycol type activators, alkylphenol ethylene oxide adduct type activators, and polyhydric alcohol type activators that are derivatives of polyhydric alcohols such as glycerin, sorbitol, and sorbitan. . Among these surfactants, it is preferable to use at least one of an anionic surfactant and a nonionic surfactant. These surfactants may be used alone or in combination of two or more.

  The amount of the surfactant used is not particularly limited as long as the object of the present invention is not impaired. Typically, the amount of the surfactant used is preferably 1% by mass or more and 10% by mass or less with respect to the mass of the binder resin.

  An aqueous medium dispersion containing fine particles of the binder resin can be prepared by adding water to the binder resin melt thus prepared and further stirring and mixing. As a device for stirring the binder resin melt and water, a stirring device having a function of maintaining the temperature of the contents is preferable in order to hold the binder resin in a molten state. As a suitable method for maintaining the temperature of the contents in the stirring device, there is a method of using a stirring device equipped with a jacket and circulating hot water, water vapor, or heat medium oil at a predetermined temperature in the jacket. As a specific example of a suitable stirring apparatus, a heating kneading apparatus (TK Hibis Disper Mix HM-3D-5 (manufactured by PRIMIX Corporation)) may be mentioned.

The particle diameter of the fine particles of the binder resin contained in the aqueous medium dispersion containing the fine particles of the binder resin obtained by stirring the melt of the binder resin and water is the same as that of the binder resin melt and water. It can be adjusted by adjusting the stirring speed when confusing. The volume average particle diameter (D ₅₀ ) of the fine particles of the binder resin is preferably 1 μm or less, and more preferably 0.05 μm or more and 0.5 μm or less. When the particle size of the fine particles of the binder resin is in such a range, the particle size distribution is sharp and it is easy to obtain a toner having a uniform shape, so that variations in toner performance and productivity are reduced. The volume average particle size (D ₅₀ ) of the fine particles of the binder resin can be measured using a laser diffraction / scattering particle size distribution measuring device (LA-950 (manufactured by Horiba, Ltd.)).

  Moreover, when using a polyester resin as the type of the binder resin, as a prior treatment for preparing the binder resin fine particles, at least a part of the oligomer having a molecular weight of 1000 or less contained in the polyester resin is removed from the polyester resin. It is preferable to prepare a low oligomer polyester resin having a reduced oligomer content and use the resulting low oligomer polyester resin as a binder resin. In the aggregation method, by using a low oligomer polyester resin, it becomes easy to incorporate a release agent into the toner, and it is easy to obtain a toner having excellent low-temperature fixability.

  As a method for removing at least a part of the oligomer having a molecular weight of 1000 or less contained in the polyester resin, a method in which the polyester resin is treated with an aqueous solution of a basic substance, or a low molecular weight component having a molecular weight of 1000 or less in the polyester resin is used. The method of processing using the organic solvent which can melt | dissolve selectively is mentioned. Among these methods, a method of treating the polyester resin with an aqueous solution of a basic substance is preferable in that the removal efficiency of the oligomer in the polyester resin is high.

  In addition, when processing a polyester resin using the aqueous solution of a basic substance, or an organic solvent, it is preferable to use the pulverized polyester resin. The particle diameter of the pulverized polyester resin is not particularly limited, but is preferably 10 μm or more and 1 mm or less, more preferably 10 μm or more and 100 μm or less, and particularly preferably 10 μm or more and 50 μm or less. If the particle size of the target polyester resin is too small, the pulverization operation is not easy. When the target particle diameter of the polyester resin is too large, the oligomer removal efficiency is lowered.

  Hereinafter, a method for treating a polyester resin with an aqueous solution of a basic substance will be described as a suitable example of a method for removing at least a part of an oligomer having a molecular weight of 1000 or less contained in the polyester resin. In addition, the method of removing a predetermined | prescribed oligomer from a polyester resin is not limited to the following method.

  First, the polyester resin is pulverized to about 20 μm to 40 μm using a pulverizer to obtain a polyester resin powder. The obtained polyester resin powder, an aqueous solution of a basic substance, and water are mixed to obtain a mixture. The temperature of the resulting mixture is raised to a temperature above the melting point of the polyester resin. After cooling the mixture to room temperature, the polyester resin is filtered from the mixture. The recovered polyester resin is washed with water and dried to obtain a low oligomer polyester resin which is a binder resin having a reduced oligomer content.

  The basic substance used in the above method is not particularly limited as long as the oligomer can be removed from the polyester resin. Specific examples of the basic substance include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, and alkali metal carbonates such as sodium carbonate and potassium carbonate. Two or more basic substances may be used in combination.

(Preparation method of release agent fine particles)
Hereinafter, a suitable example of the method for preparing the release agent fine particles will be described. The method for preparing the release agent fine particles is not limited to the method described below.

  First, the release agent is pulverized to about 100 μm or less in advance to obtain a release agent powder. A release agent powder is added to an aqueous medium containing a surfactant to prepare a slurry. The resulting slurry is then heated to a temperature above the melting point of the release agent. A strong shearing force is applied to the heated slurry using a homogenizer or a pressure discharge type disperser to prepare an aqueous dispersion containing release agent fine particles.

  As a device for applying a strong shearing force to the dispersion, NANO3000 (manufactured by Miki Co., Ltd.), nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.), micro full dizer (manufactured by MFI), gorin homogenizer (manufactured by Manton Gorin), and Clare mix W motion (M Technique Co., Ltd.) is listed.

The volume average particle diameter (D ₅₀ ) of the fine particles of the release agent contained in the aqueous medium dispersion containing the fine particles of the release agent is preferably 1 μm or less, and more preferably 0.1 μm or more and 0.7 μm or less. By using fine particles of a release agent having a particle diameter in such a range, it is easy to obtain a toner in which the release agent is uniformly dispersed in the binder resin. The volume average particle size of the fine particles of the release agent (D ₅₀₎ can be measured in the same manner as the volume average particle diameter of the binder resin (D _50).

(Preparation method of fine particles containing binder resin and release agent)
Hereinafter, a preferred example of a method for preparing fine particles containing a binder resin and a release agent will be described. The method for preparing the fine particles containing the binder resin and the release agent is not limited to the method described below.

  The fine particles containing the binder resin and the release agent are the same as those described above except that the release resin is contained in the binder resin melt with respect to the preferred method for preparing the fine particles of the binder resin. It can be prepared using a method similar to the preferred method for preparing the fine particles of the resin.

  The method for incorporating a release agent into the binder resin melt is not particularly limited. As a preferred method of incorporating a release agent into the binder resin melt, (a) a method of melting the resulting mixture after mixing the solid state binder resin and the release agent, and (b) release. After the mold is heated and melted, the binder resin is added to the melted release agent and both are melted by heating; and (c) the binder resin is heated and melted and then melted An example is a method in which a release agent is added to the binder resin and both are heated and melted.

(Preparation method of fine particles of colorant)
Hereinafter, a suitable example of a method for preparing fine particles of a colorant will be described. The method for preparing the fine particles of the colorant is not limited to the method described below.

  Fine particles containing a colorant are obtained by dispersing the colorant and, if necessary, a component such as a colorant dispersant in an aqueous medium containing a surfactant by a known disperser. The type of the surfactant is not particularly limited, and any of an anionic surfactant, a cationic surfactant, and a nonionic surfactant can be used. The amount of the surfactant used is not particularly limited, but is preferably not less than the critical micelle concentration (CMC).

  Dispersers used for the dispersion treatment are not particularly limited, and pressure dispersers such as ultrasonic dispersers, mechanical homogenizers, manton gourins, and pressure homogenizers, sand grinders, horizontal and vertical bead mills, and ultra apex mills. Media type dispersers such as (manufactured by Kotobuki Kogyo Co., Ltd.), dyno mill (manufactured by WAB Co., Ltd.), MSC mill (manufactured by Nippon Coke Kogyo Co., Ltd.) can be used.

The volume average particle diameter (D ₅₀ ) of the fine particles of the colorant is preferably 0.05 μm or more and 0.2 μm or less.

[Step (ii): Aggregation step of fine particles]
Using various fine particles obtained in the step (i), an aqueous medium dispersion containing fine particles of a binder resin and fine particles of a release agent, or fine particles containing a binder resin and a release agent After preparing the aqueous medium dispersion containing, fine particles contained in the aqueous medium dispersion are aggregated to form fine particle aggregates. The aqueous medium dispersion liquid may further contain fine particles of a colorant as necessary.

  The method for aggregating the fine particles is not particularly limited as long as the object of the present invention is not impaired. A suitable method for aggregating the fine particles includes a method of adding an aggregating agent to the aqueous medium dispersion containing the fine particles.

  Examples of the flocculant include inorganic metal salts, inorganic ammonium salts, and divalent or higher metal complexes. Inorganic metal salts include metal salts such as sodium sulfate, sodium chloride, calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride and polyaluminum hydroxide. An inorganic metal salt polymer is mentioned. Examples of inorganic ammonium salts include ammonium sulfate, ammonium chloride, and ammonium nitrate. Further, a quaternary ammonium salt type cationic surfactant, polyethyleneimine can also be used as a flocculant.

  As the flocculant, a divalent metal salt or a monovalent metal salt is preferably used. In addition, the aggregation rate of fine particles when a monovalent metal salt is used is slower than the aggregation rate of fine particles when a divalent metal salt is used. For this reason, the aggregation speed | rate of microparticles | fine-particles can be adjusted later using a monovalent metal salt using a divalent metal salt as an aggregating agent. As described above, since the divalent metal salt and the monovalent metal salt have different fine particle aggregation rates, the combined use of these salts allows the fine particle agglomeration while controlling the particle diameter of the obtained fine particle aggregate. It is easy to make the particle size distribution of the aggregate sharp.

  The addition amount of the flocculant is not particularly limited as long as the object of the present invention is not impaired, and is preferably 0.1 mmol / g or more and 10 mmol / g or less with respect to the solid content of the fine particle dispersion. Further, the addition amount of the flocculant is preferably adjusted as appropriate according to the type and amount of the surfactant contained in the fine particle dispersion.

  The flocculant is added at a temperature below the glass transition point of the binder resin after adjusting the pH of the fine particle dispersion as necessary. In particular, when the binder resin is a polyester resin, the flocculant is added after adjusting the pH of the fine particle dispersion to the alkali side, preferably to pH 10 or higher. Thereby, the aggregation of the fine particles can be made uniform, and the particle size distribution of the fine particle aggregate can be sharpened. The flocculant may be added at one time or may be added sequentially.

  After the aggregation has progressed until the fine particle aggregate has a desired particle size, an aggregation terminator is preferably added. Examples of the aggregation terminator include sodium chloride and sodium hydroxide. Thus, a fine particle aggregate can be obtained.

[Step (iii): Fine particle uniting step]
In the coalescing step of fine particles, the fine particle aggregate obtained in the step (ii) is heated in an aqueous medium to coalesce the components contained in the fine particle aggregate to form toner particles. In the coalescence process, the shape of the fine particle aggregate gradually approaches a spherical shape by heating the fine particle aggregate. This is because the melt viscosity of the binder resin decreases due to the temperature rise, and the shape of the fine particle aggregate changes in the direction of spheroidization due to the surface tension. By controlling the temperature and time during heating, the spheroidization degree of the toner particles obtained can be controlled to a desired value.

  The temperature at which the fine particle aggregate is heated in the fine particle coalescence step is not particularly limited as long as the coalescence of the components contained in the fine particle aggregate proceeds well. The temperature at which the fine particle aggregate is heated is preferably at least 10 ° C. higher than the glass transition temperature (Tg) of the binder resin and lower than the melting point (Tm) of the binder resin. By heating the agglomerated particles to a temperature in such a range, the coalescence of the components contained in the agglomerated particles can be promoted well, and a toner with a suitable sphericity can be easily prepared.

In addition, when the electrostatic latent image developing toner of the present invention is produced using the aggregation method, in addition to the steps (i) to (iii) described above, the following steps (iv) to (vi) are performed as necessary. May be included.
Step (iv): A washing step of washing the toner obtained in step (iii).
Step (v): A drying step of drying the toner obtained in step (iii).
Step (vi): an external addition step of attaching an external additive to the surface of the toner obtained in the step (iii).
Hereinafter, steps (iv) to (vi) will be described in order.

[Step (iv): Cleaning step]
The toner particles obtained in step (iii) are washed with water as necessary. The cleaning method is not particularly limited, and examples include the following methods. That is, the toner particles are recovered as a wet cake from the toner particle dispersion by solid-liquid separation, and the resulting wet cake is washed with water, or the toner particles in the toner particle dispersion are precipitated. In this method, the supernatant liquid is replaced with water, and the toner particles are redispersed in water after the replacement. Among these, cleaning using a filter press device is preferable.

[Step (v): Drying step]
The toner particles obtained in step (iii) are dried as necessary. The method for drying the toner particles is not particularly limited. Suitable drying methods include methods using a dryer such as a spray dryer, fluidized bed dryer, vacuum freeze dryer, and vacuum dryer. Among these methods, a method using a spray dryer is more preferable because aggregation of toner particles during drying is easily suppressed. In the case of using a spray dryer, the external additive can be attached to the surface of the toner particles by spraying a dispersion of the external additive such as silica together with the dispersion of the toner particles.

[Step (vi): External addition step]
The electrostatic latent image developing toner produced using the method of the present invention may be one having an external additive attached to the surface thereof, if necessary. The method for attaching the external additive to the surface of the toner particles is not particularly limited. As a suitable method, a method of mixing the toner particles and the external additive by using a mixer such as a Henschel mixer or a Nauter mixer and adjusting the conditions so that the external additive is not buried in the toner surface can be mentioned. .

≪Internal cohesive force (F) and interfacial adhesion force (f) ≫
The toner of the present invention described above has an internal cohesive force (F) of 5N or more and 10N or less and an interfacial adhesion force (f) of 0.5N or more and 1N or less as measured using a specific method described later. . By setting the internal cohesive force (F) and interfacial adhesion force (f) of the toner within such ranges, the toner is excellent in low-temperature fixability and is well fixed in a wide temperature range, and a fixing roller for a recording medium It is possible to suppress wrapping around. Hereinafter, the internal cohesive force (F) and the interfacial adhesion force (f) will be described.

(Internal cohesion (F))
The internal cohesion force (F) of the toner of the present invention is determined by adjusting the number average molecular weight (Mn) and the mass average molecular weight (Mw) of the binder resin contained in the toner, and the binder resin contained in the toner. It can be adjusted by a method such as a method of changing the type of monomer used in the synthesis of. When the internal cohesive force (F) of the toner is excessively small, the toner can be fixed well in the temperature range of the low temperature range, but is difficult to fix well in the temperature range of the high temperature range, and the recording medium is wound around the fixing roller. It is difficult to suppress. On the other hand, when the internal cohesive force (F) of the toner is excessive, the toner can be fixed satisfactorily in the temperature range of the high temperature range, but the release agent component is not easily eluted from the toner at the time of fixing at low temperature. It is difficult to fix well in the temperature range. Hereinafter, a method for measuring the internal cohesive force (F) will be described.

<Method for measuring internal cohesive force (F)>
The internal cohesive force (F) is measured using a measuring apparatus M _F 100 as shown in FIG. The measuring apparatus M _F 100 includes a sample stage S ₁ 400 and a pressurizing unit P ₁ 200.
The sample stage S ₁ 400 is composed of an aluminum plate 401 having a thickness of 3 mm and having a heater H _S 403 attached to the lower surface.
Pressing _P 1 200 includes a heater _H P 202, a load cell 201 mounted on the upper surface of the heater _H P 202, attached to the lower surface, under an aluminum bottom polyimide resin film 205 (thickness of the heater _H P 202 And a cylindrical indenter 204 covered with 5 mm and a surface roughness of 1.5 μm. Then, pressing _P 1 200 is above the sample stage _S 1 400, is disposed movably in a direction perpendicular to the surface direction of the sample stage _S 1 400. In the following step I), in order to confirm the temperatures of the pressurization part P ₁ 200 and the sample stage S ₁ 400, as shown in FIG. 1, the pressurization part P ₁ 200 uses the thermocouple T _P 203 as a sample. Stages S ₁ 400 are preferably each provided with a thermocouple T _P 402.

Specifically, the internal cohesion force (F) is measured using a measuring apparatus M _F 100 having the above-described configuration, using a method including the following steps I) to III).
Step I) Using the heater H _S 403 and the heater H _P 202, the pressure unit P ₁ 200 and the sample stage S ₁ 400 are heated to 150 ° C., respectively.
Step II) The temperature of the pressure unit P ₁ 200 and the sample stage S ₁ 400 is maintained at 150 ° C., and the toner sample 301 is placed on the sample stage S ₁ 400 so as to be 1.0 g / cm ² . The toner sample 301 is pressurized for 30 seconds at a pressure of 10 N / cm ² using the pressure unit P ₁ 200.
Step III) After pressurization, the pressurization part P ₁ 200 is raised at a speed of 60 mm / second, and the pressurization part is measured using the load cell 201 from the start until the pressurization part P ₁ 200 rises by 10 cm. The maximum value of the load applied between P ₁ 200 and sample stage S ₁ 400 was measured. The load measured using the load cell 201 is transmitted as an electrical signal to an external information processing apparatus such as a PC (personal computer) connected to the load cell 201, and the pressurizing unit P ₁ 200, the sample stage S ₁ 400, Can be measured as a force (N) applied between the pressurizing part P ₁ 200 and the sample stage S ₁ 400.

(Interface adhesion (f))
The interfacial adhesion force (f) of the toner of the present invention can be adjusted by a method such as a method of adjusting the content of the release agent contained in the toner and a method of adjusting the dispersibility of WAX. When the interfacial adhesion force (f) of the toner is too small, the toner is less likely to be satisfactorily fixed in a low temperature range because the permeability of the toner to the recording medium tends to decrease. On the other hand, when the interfacial adhesion force (f) of the toner is excessive, the toner is difficult to be satisfactorily fixed in a low temperature range. Hereinafter, a method for measuring the interfacial adhesion force (f) will be described.

<Measurement of interface adhesion (f)>
The interfacial adhesion force (f) is measured using a measuring apparatus M _f 500 as shown in FIG. The measuring device M _f 500 is obtained by replacing the sample stage S ₁ 400 of the measuring device M _F 100 with the following sample stage S ₂ 600.
The sample stage S ₂ 600 is made of PFA resin having a thickness of 25.3 μm and a surface roughness (Ra) of 0.30 μm on the surface of a 3 mm thick aluminum plate having a heater H _S 403 attached to the lower surface. It consists of a coated PFA coated aluminum plate 601. The PFA resin is a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer.

Then, using the measuring device _M f 500, measures interfacial adhesion force (f) using a method comprising the step I) to III).

  The electrostatic latent image developing toner of the present invention described above is excellent in low-temperature fixability, is well fixed in a wide temperature range, and can suppress winding of a recording medium around a fixing roller. Therefore, the electrostatic latent image developing toner of the present invention is suitably used in various image forming apparatuses.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited at all by the Example.

[Examples 1-4, Comparative Examples 1-3, 5, and 6]
[Step (i): Fine particle preparation step]
(Preparation of binder resin dispersions A to E)
Binder resin dispersions A to E were prepared according to the following method.
As the binder resin, a polyester resin having a mass average molecular weight (Mw), a number average molecular weight (Mn), a melting point (Tm), a glass transition point (Tg), and an acid value described in Table 1 was used.

  Specifically, first, the polyester resin was pulverized using a pulverizer to obtain a polyester resin powder having an average particle diameter of about 30 μm. Next, 200 g of the obtained polyester resin powder, 30 g of a 1N-sodium hydroxide aqueous solution (concentration 4%), and 770 g of ion-exchanged water are mixed using a mixing device to obtain an aqueous suspension containing the polyester resin powder. It was.

  The obtained aqueous suspension containing the polyester resin powder was put into a 2 L round bottom stainless steel container equipped with a condenser and a stirrer (RW20 digital (manufactured by IKA)), and further an anionic surfactant (sodium lauryl sulfate, About 1% of Emar 0 (manufactured by Kao Corporation) was added to the resin, the liquid temperature was kept at 95 ° C., and the mixture was stirred at a rotation speed of 200 rpm for 30 minutes. Thereafter, the contents of the container were rapidly cooled to room temperature, and then the aqueous suspension containing the polyester resin powder was filtered using a # 300 mesh filter to obtain a low-oligomer polyester resin wet cake. The low oligomer polyester resin was obtained by washing the wet cake of the low oligomer polyester resin with water and drying.

  The obtained low-golimer polyester resin was used as a binder resin and charged into a heating and kneading apparatus (TK Hibis Dispermix HM-3D-5 (manufactured by Primics Co., Ltd.)) equipped with a temperature adjusting jacket. The polyester resin was melted by heating to 120 ° C. while stirring at a revolution of 20 rpm and a rotation of 48 rpm. Thereafter, 80 g of triethanolamine (basic compound) and 80 g of an aqueous solution having a concentration of 25% by mass of sodium lauryl sulfate (surfactant, Emar 0 (manufactured by Kao Corporation)) were added to the melt, Stirring was continued at 97 rpm for 15 minutes. Thereafter, 2870 g of 98 ° C. ion-exchanged water was added to the melt at a rate of 50 g / min to obtain a resin emulsion. Thereafter, the emulsion was cooled to 50 ° C. at a rate of 5 ° C./min to obtain an aqueous medium dispersion containing fine particles of the binder resin. The solid content concentration of the obtained binder resin fine particle dispersion was 25% by mass. The average particle diameter of the resin fine particles contained in the fine particle dispersion of the binder resin was 115 nm. The particle diameter of the fine particles of the binder resin was measured using a particle diameter measuring device (LA-950 (manufactured by Horiba, Ltd.)).

(Preparation method of release agent fine particle dispersion)
-Preparation method of release agent fine particle dispersion A 200 g of release agent (ester wax, WEP-3 (manufactured by NOF Corporation)), 20 g of sodium lauryl sulfate (Emar 0 (manufactured by Kao Corporation)), and ions After mixing with 780 g of exchange water and heating to 90 ° C., the mixture was emulsified with CLEARMIX (CLM-2.2S (manufactured by M Technique Co., Ltd.)) for 10 minutes to obtain a fine particle dispersion A of a release agent. . The solid content concentration of the obtained fine particle dispersion A of the release agent was 10% by mass. The average particle diameter of the fine particles of the release agent contained in the fine particle dispersion A of the release agent was 250 nm. The particle size of the release agent fine particles was measured using the same method as the particle size of the fine particles of the binder resin.

-Preparation method of release agent fine particle dispersion B 200 g of release agent (paraffin wax, HNP-9PD (manufactured by Nippon Seiwa Co., Ltd.), melting point 75 ° C.), and anionic surfactant (Emar E27C) as a surfactant (Made by Kao Corporation) 2 g and 800 g of ion-exchanged water were mixed and heated to 90 ° C., and then stirred using a homogenizer (Ultra Turrax T50 (manufactured by IKA)) for 5 minutes at a stirring speed of 2,000 rpm. Was emulsified. Furthermore, using a high-pressure homogenizer (NV-200 (manufactured by Yoshida Kikai Kogyo Co., Ltd.), heating system added), emulsification is performed under the processing conditions of 100 ° C. and discharge pressure of 100 MPa, and the fine particle dispersion B of the release agent Got. The solid content concentration of the fine particle dispersion B of the obtained release agent was 10% by mass. The average particle diameter of the fine particles of the release agent contained in the fine particle dispersion B of the release agent was 150 nm. The particle size of the release agent fine particles was measured using the same method as the particle size of the fine particles of the binder resin.

(Preparation method of pigment fine particle dispersion)
100 g of pigment (cyan pigment, CI pigment blue 15: 3 (copper phthalocyanine)), 20 g of sodium polyoxyethylene lauryl sulfate (Emar E27C (manufactured by Kao Corporation)) and 380 g of ion-exchanged water are mixed. Using an ultra apex mill (manufactured by Kotobuki Kogyo Co., Ltd.) into which 400 ml of beads (zirconia, φ0.1) is charged in a stirring vessel, a dispersion treatment is performed under conditions of a rotor peripheral speed of 10 m / sec and a holding time of 2 hours. A pigment fine particle dispersion was obtained. The resulting pigment fine particle dispersion had a pigment concentration of 20% by mass and a total solid content of 21% by mass. The average particle diameter of the pigment fine particles contained in the pigment fine particle dispersion was 113 nm. The particle diameter of the pigment fine particles was measured using the same method as the particle diameter of the binder resin fine particles.

[Step (ii): Aggregation step of fine particles]
In a stainless steel 2 L round bottom flask, 340 g of a binder resin dispersion prepared using the above method, a release agent dispersion of an amount shown in Tables 2 to 4, and 25 g of a pigment dispersion, 500 g of ion-exchanged water was added, and these were mixed at 25 ° C. Next, the mixture in the flask was stirred at a rotation speed of 200 rpm using a stirring blade. The pH of the mixture in the flask was adjusted to 10 using an aqueous sodium hydroxide solution, and then the mixture was stirred for 10 minutes. Thereafter, 10 g of a magnesium chloride hexahydrate aqueous solution (flocculating agent) having a concentration of 50% by mass was dropped into the flask over 5 minutes. Next, the mixture in the flask was heated at a rate of 0.2 ° C./min to start agglomeration of fine particles. After the temperature increase was stopped at 50 ° C., the mixture in the flask was stirred. The mixture was kept at 50 ° C. for 30 minutes to advance the aggregation of the fine particles. Thereafter, 50 g of an aqueous sodium chloride solution having a concentration of 20% by mass was added to the flask to stop the progress of the aggregation of the fine particles, thereby obtaining an aqueous medium dispersion containing the fine particle aggregates.

[Step (iii): Fine particle uniting step]
100 g of an aqueous solution of sodium lauryl sulfate (Emar 0 (manufactured by Kao Corporation)) having a concentration of 5% by mass was added to the obtained aqueous medium dispersion containing fine particle aggregates. Next, the aqueous medium dispersion containing fine particle aggregates was heated to 65 ° C. at a temperature rising rate of 0.2 ° C./min. After the temperature was raised to 65 ° C., stirring was performed at the same temperature for 1 hour at 300 rpm to unite the toner components contained in the fine particle aggregate and to control the shape of the fine particle aggregate into a spherical shape. Thereafter, the aqueous medium dispersion containing fine particle aggregates was cooled to 25 ° C. at a rate of 10 ° C./min to obtain an aqueous medium dispersion containing the shape-controlled fine particle aggregates as toner base particles.

[Step iv): Cleaning step]
Using a Buchner funnel, a wet cake of toner base particles was filtered from an aqueous medium dispersion containing toner base particles. The wet cake of toner base particles was again dispersed in ion exchange water to wash the toner. The same washing using the ion exchange water of the toner mother particles was repeated 6 times.

[Step (v): Drying step]
A wet cake of toner base particles was dispersed in an aqueous ethanol solution having a concentration of 50% by mass to prepare a slurry. The obtained slurry was supplied to a continuous surface reformer (Coat Mizer (manufactured by Freund Sangyo Co., Ltd.)) to dry the toner base particles in the slurry to obtain toner base particles. Drying conditions using the coatizer were a hot air temperature of 45 ° C. and a blower air volume of 2 m ³ / min.

[Step (vi): External addition step]
The toner base particles obtained in each of Examples and Comparative Examples were subjected to external addition treatment.
Specifically, 100 parts by mass of toner base particles and 0.4 parts by mass of positively charged silica (silica 90G (manufactured by Nippon Aerosil Co., Ltd.): silica surface treated with silicone oil and aminosilane) Using a 5 L Henschel mixer (manufactured by Mitsui Miike Kogyo Co., Ltd.), the mixture was mixed for 5 minutes under the condition of a stirring speed of 30 m / sec to adhere the external additive. Thereafter, the toner was sieved using a sieve of 300 mesh (aperture 48 μm).

[Comparative Example 4]
As the toner of Comparative Example 4, a toner for TASKalfa500Ci (manufactured by Kyocera Document Solutions Co., Ltd.) was used.

  Of the toners of Examples and Comparative Examples thus obtained, the toner of Example 1 was measured using a particle size distribution measuring device (Microtrack UPA150 (manufactured by Nikkiso Co., Ltd.)), and the volume average particle size (MV). , MV / MN value and sphericity were measured. The toner of Example 1 had a volume average particle diameter (MV) of 5.5 μm, a sphericity of 0.978, and an MV / MN value of 1.2.

≪Measurement and evaluation≫
For the toners of Examples 1 to 4 and Comparative Examples 1 to 6, the internal cohesive force (F), the interfacial adhesion force (f), and the release agent content were measured according to the following method to determine the fixability, The winding of the recording medium was evaluated. The measurement results of the internal cohesive force (F), the interfacial adhesion force (f), and the release agent content of the toners of Examples 1 to 4 and Comparative Examples 1 to 6, and the evaluation results of the fixing property are shown in Tables 2 Write to 4.

<Measurement of internal cohesion (F)>
Using a measuring device M _F described above were measured internal cohesion (F) using a method comprising the steps of I) to III).
A step I) heating element _{H S,} with a heating element _{H P,} the pressure portion _{P 1} and the sample stage _{S 1,} and heated to respectively 0.99 ° C..
Step II) The temperature of the pressure unit P ₁ and the sample stage S ₁ is maintained at 150 ° C., and a toner sample is placed on the sample stage S ₁ so as to be 1.0 g / cm ^2. ₁ was used to pressurize the toner sample at a pressure of 10 N / cm ² for 30 seconds.
Step III) After pressing, at a rate 60 mm / sec, to increase the pressure portion _{P 1,} the pressure portion _{P 1} from the start until the rising 10 cm, measured using the load cell, pressure portion _{P 1} the maximum value of the load applied between the sample stage S ₁ were measured.

<Measurement of interfacial adhesion (f)>
The interfacial adhesion force (f) was measured using the above-described measuring apparatus M _f using a method including the above steps I) to III).

<Method for measuring release agent content>
Using a differential scanning calorimeter (DSC-6200 (manufactured by Seiko Instruments Inc.) as a measurement device, temperature detection of the detection unit was performed using melting points of indium and zinc, and heat correction was performed using heat of fusion of indium) The endothermic curve of the toner was measured according to ASTM D3418-8. 10 mg of a measurement sample was put in an aluminum pan, and an empty aluminum pan was used as a reference. Calculated from the peak derived from the mold release agent using the endothermic curve of the toner obtained by measuring the temperature range from 60 ° C. to 80 ° C. under the temperature increase rate of 10 ° C./min and normal temperature and humidity. The content (% by mass) of the release agent in the toner was determined from the endothermic amount when the release agent was melted.

A two-component developer used for evaluation of fixability was prepared according to the following method.
[Preparation of two-component developer]
(Preparation of carrier)
Each raw material is blended so as to be 39.7 mol% in terms of MnO, 9.9 mol% in terms of MgO, 49.6 mol% in terms of Fe ₂ O ₃ , and 0.8 mol% in terms of SrO, and then water is added to the wet ball mill. And pulverized and mixed for 10 hours. The resulting mixture was dried and then kept at 950 ° C. for 4 hours. Next, the mixture was pulverized with a wet ball mill for 24 hours to prepare a slurry. After granulating and drying the slurry, the granulated product was held at 1270 ° C. for 6 hours in an atmosphere with an oxygen concentration of 2%, and then crushed and adjusted in particle size to obtain manganese-based ferrite particles (carrier core material). . The obtained manganese-based ferrite particles had an average particle diameter of 35 μm and a saturation magnetization of 70 Am ² / kg when the applied magnetic field was 3000 (10 ³ / 4π · A / m).

  Next, a polyamideimide resin (copolymer of trimellitic anhydride and 4,4'-diaminodiphenylmethane) was diluted with methyl ethyl ketone to prepare a resin solution. Subsequently, tetrafluoroethylene / hexafluoropropylene copolymer (FEP) and silicon oxide (2% by mass of the total amount of the resin) are dispersed in the resin solution, and an amount of carrier coat liquid that is 150 g in terms of solid content. Got. The mass ratio of polyamideimide resin and FEP was 2/8 as polyamideimide resin / FEP, and the solid content ratio of the resin solution was 10 mass%.

  Using the obtained carrier coat solution, 10 kg of manganese-based ferrite particles were coated using a fluidized bed coating apparatus (Spiracoater SP-25 (Okada Seiko Co., Ltd.)). Thereafter, the manganese-based ferrite particles coated with the resin were fired at 220 ° C. for 1 hour to obtain a resin-coated ferrite carrier having a resin coating amount of 3 mass%.

(Mixing of toner and carrier)
The toner and carrier obtained in each Example and Comparative Example were mixed with a rocking mixer (RM-10 (manufactured by Aichi Electric Co., Ltd.) so that the toner mass relative to the mass of the two-component developer was 12.0 mass%. )) And mixed for 30 minutes at 78 rpm under normal temperature and humidity conditions to obtain a two-component developer.

<Fixability evaluation>
Using the resulting two-component developer and toner, it has an aluminum fixing roller coated with PFA resin with a film thickness of 30 μm ± 10 μm and a surface roughness (Ra) of 5 μm, and the fixing temperature can be adjusted. Using a modified copying machine (TASKalfa 500ci (manufactured by Kyocera Document Solutions Co., Ltd.)), a linear speed of 300 mm / second and a toner applied amount of 1.5 mg were set to form an unfixed solid image on a recording medium. In the range of 80 ° C. to 200 ° C., the fixing temperature of the fixing device of the multifunction machine was increased from 80 ° C. by 10 ° C. to fix an unfixed solid image. Using the obtained fixed image, the minimum fixing temperature and the maximum fixing temperature were measured based on the following measurement method. Fixability was evaluated based on the following criteria.
○ (Acceptable): The toner was satisfactorily fixed on the recording medium at a fixing temperature ranging from 80 ° C. to 200 ° C.
X (failed): The fixing lower limit temperature exceeds 80 ° C., and the fixing upper limit temperature is less than 200 ° C.

(Measurement method of minimum fixing temperature and maximum fixing temperature)
For a solid image formed by changing the fixing temperature by 10 ° C., the image density of the fixed solid image before and after the fastness test was measured, and the density ratio was calculated from the image density before and after the fastness test according to the following formula. The temperature at which a solid image having a density ratio of 80% or more could be fixed was defined as a fixing possible temperature. The lower limit of the fixable temperature was defined as the minimum fixing temperature. Further, the upper limit value of the fixable temperature was set as the fixing upper limit temperature. The fastness test was conducted using a Gakushin type friction fastness tester (JIS L 0849II type (manufactured by Yasuda Seiki Seisakusyo)) under a load of 200 g and a rubbing operation of 20 strokes. The image density was measured using a reflection densitometer (RD-918 (manufactured by Gretag Macbeth)).
Density ratio (%) = (image density after friction / image density before friction) × 100

<Wound of recording medium>
The winding of the recording medium was evaluated using the copying machine used for the evaluation of the fixing property. The separation claw that comes into contact with the surface of the fixing roller of the copying machine and separates the recording medium attached to the fixing roller is removed from the copying machine, and 100 sheets are continuously 5 cm at a fixing temperature of 200 ° C. A solid image of × 5 cm was formed at the tip of the recording medium. The winding of the recording medium was evaluated according to the following criteria. The recording medium used for the evaluation was A4 size high-quality paper (70 g / m ² ).
○: No winding occurred in the image formation of 100 sheets.
X: Winding occurred when 100 images were formed.

  According to Examples 1 to 4, the electrostatic cohesive image developing toner including the binder resin and the release agent has an internal cohesive force (F) measured using the specific method described above of 5 N or more. When it is 10N or less and the interfacial adhesion force (f) is 0.5N or more and 1N or less, it is excellent in low-temperature fixability, can be fixed well in a wide temperature range, and can suppress the winding of the recording medium around the fixing roller. I understand.

  According to Comparative Example 1, a toner having an excessive internal cohesive force (F) measured using the above-described method has a narrow fixing temperature range, and it is difficult to suppress winding of the recording medium around the fixing roller. I understand.

  According to Comparative Examples 2 and 6, the toner having an excessive interfacial adhesion force (f) measured using the above-described method has a narrow fixing temperature range and suppresses the winding of the recording medium around the fixing roller. I find it difficult.

  According to Comparative Examples 3 and 4, it can be seen that the toner having an excessive internal cohesive force (F) measured using the above-described method has a narrow fixing temperature range.

  According to Comparative Example 5, it can be seen that the toner having an excessive interface adhesion force (f) measured using the above-described method has a narrow fixing temperature range. This is presumably because the permeability of the toner to the recording medium tends to decrease and the low-temperature fixability of the toner is not good.

100 Measuring device M _F
201 load cell 202 heater _{H P}
203 Thermocouple T _P
204 Cylindrical indenter 205 Polyimide resin film 301 Toner sample 401 Aluminum plate 402 Thermocouple T _P
403 heater _{H S}
500 Measuring device M _f
601 PFA coated aluminum plate

Claims (1)

An electrostatic latent image developing toner comprising a binder resin and a release agent,
The binder resin is a polyester resin obtained by condensation polymerization of a monomer composed of a divalent or trivalent or higher alcohol component and a divalent or trivalent or higher carboxylic acid component;
The number average molecular weight of the binder resin is 1500 or more and 2500 or less,
The binder resin has a mass average molecular weight of 3500 or more and 6500 or less,
The electrostatic latent image developing toner has an internal cohesion force (F) of 5 N or more and 10 N or less, and an interface adhesion force (f) of 0.5 N or more and 1 N or less,
The internal cohesive force (F) is
Heater H _S on the lower surface is attached, the sample stage S ₁ consisting of an aluminum plate having a thickness of 3 mm,
Comprising a heater H _P, and a load cell attached to an upper surface of the heater H _P, attached to the lower surface of the heater H _P, a cylindrical indenter under an aluminum bottom are coated with a polyimide resin film, the said above the sample stage S _1, the pressure portion P ₁ which is disposed movably in a direction perpendicular to the surface direction of the sample stage S _1,
Using a measuring device _{M F} comprise the following step I) to III):
Step I) and the heating member _{H S,} with the heating member _{H P,} the pressing _{P 1} and the sample stage _{S 1,} is heated to respectively 0.99 ° C.,
II) The temperature of the pressure part P ₁ and the sample stage S ₁ is maintained at 150 ° C., and a toner sample is placed on the sample stage S ₁ so as to be 1.0 g / cm 2. using parts _{P 1,} a pressure of 10 N / cm @ 2, the step of pressurizing the toner sample for 30 seconds, and III) after pressing, at a rate 60 mm / sec, the increase the pressing P1, the start pressure the step of measuring the before pressing P ₁ is raised 10 cm, measured using the load cell, the maximum value of the load applied between the pressing P ₁ and the sample stage S _1,
Measured using a method comprising
The interface adhesion force (f) is:
Wherein said sample stage _{S 1} of the measuring device _{M F,} and the heater _{H S} is attached to the lower surface, the surface of an aluminum plate having a thickness of 3 mm, thickness 25.3Myuemu, roughness (Ra) is 0. 30μm of PFA resin (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) is retrofit sample stage _{S 2} made of PFA-coated aluminum plate was coated by using a measuring device _{M f,} the step I) to III ) Measured using a method comprising
Toner for electrostatic latent image development.

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