JP2014130243A - Toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner that achieves both low-temperature fixability and heat-resistance storage stability, and has sufficient charging performance, folding strength of fixed images, wide fixable temperature range, and high image loading performance.SOLUTION: A toner comprises toner particles having a core-shell structure. A binder resin is (i) a side-chain crystalline resin, (ii) has the melting point Tm of 50.0°C or higher and 90.0°C or lower; a resin forming the shell has the glass transition temperature Tg of 50.0°C or higher and (Tm+35.0)°C or lower; and the toner (i) has the storage elastic modulus G' at a temperature Tm+10.0°C (Tm+10.0) of 1.0×10Pa or more and 1.0×10Pa or less, and (ii) a ratio of the storage elastic modulus G'(Tm+10.0) to the storage elastic modulus G' at a temperature Tm+50.0°C (Tm+50.0) (G'(Tm+10.0)/G'(Tm+50.0)) of 10.0 or less.

Description

  The present invention relates to a toner used to form a toner image by developing an electrostatic latent image formed by a method such as electrophotography, electrostatic recording, or toner jet recording.

  In recent years, printers and copiers have been required to have higher speed and lower power consumption, and toner fixing performance has been improved. That is, it is desired to realize a toner that can be fixed quickly and with low energy by being rapidly melted at a lower temperature and that is excellent in low-temperature fixability.

  In order to satisfy these requirements, it is necessary to soften the toner by a technique such as lowering the molecular weight of the binder resin. However, the heat-resistant storage stability is lowered simply by softening the toner. Therefore, in order to realize a toner that achieves both low-temperature fixability and heat-resistant storage stability, a method using a resin whose main component is a portion capable of taking a crystal structure (hereinafter also referred to as a crystalline resin) as a binder resin has been studied. ing. Crystalline resins are generally excellent in response speed of changes in viscoelasticity to heat, while tending to be brittle to external forces because the main chain of resin molecules is entangled and hardly takes a structure. Therefore, when simply introducing a crystalline resin to improve low-temperature fixability, due to the characteristics of the crystalline resin, the resistance to bending of the fixed image is low, and image peeling due to bending tends to occur. is there. In addition, since the viscosity of the crystalline resin rapidly decreases after melting, it is difficult to control the viscosity to a desired viscosity in the fixing step, and the fixable temperature range is often narrowed. Furthermore, since the crystalline resin has a lower volume resistance than the amorphous resin, charge leakage tends to occur. For this reason, in a toner using a crystalline resin as a binder resin, it may be difficult to obtain good charging performance. In order to solve the above problems, toners with various ideas have been proposed.

  In Patent Document 1, it is proposed to use, as a binder resin, a crystalline resin in which a decrease in viscosity after melting is suppressed by a crosslinked structure. However, since the structure is composed of only a crystalline resin, the main chain is hardly entangled, and an improvement in bending strength cannot be expected. Also, the charging performance may be insufficient.

  Patent Document 2 proposes a toner using a binder resin obtained by copolymerizing a monomer composition containing an amorphous styrene acrylic monomer, a crystalline monomer, and a crosslinking agent. However, since the ratio of the crystalline monomer in the monomer composition is very small, it cannot be sufficiently crystallized, and most of them are considered to be amorphous (low crystallinity). Therefore, it cannot be said that the low-temperature fixing effect of the crystalline resin is maximized.

  Patent Document 3 proposes a toner in which a crystalline polyester and an amorphous styrene acrylic resin are mixed.

  However, crystalline polyester is a main-chain crystalline resin, and tends to be hindered by the surrounding resin and crystallization degree tends to decrease. For this reason, there is a concern that the low-temperature fixability may not be sufficiently exhibited because the crystallinity of the toner is greatly reduced due to heating during production. Further, on the paper surface after fixing, it is considered that the crystalline polyester and the amorphous resin are mixed and the glass transition temperature is lowered. For this reason, the fixed image is sticky even at a low temperature, and when the fixed image is left as it is, the papers stick to each other, and the image may be defective when peeled off (the image stackability is insufficient). .

  As described above, the toner in which the low-temperature fixing performance is improved by adding the crystalline resin has the low-temperature fixing performance and the heat-resistant storage stability, the sufficient charging performance, the fixing image bending strength, and the fixable temperature range. There is a long-awaited toner having a wide and high image stackability.

JP 2009-265644 A Japanese Patent Laid-Open No. 7-181726 JP 2005-266546 A

  An object of the present invention is to provide a toner that solves the above-described conventional problems.

  In other words, in a toner in which low-temperature fixing performance is improved by adding a crystalline resin, both low-temperature fixing performance and heat-resistant storage stability are compatible, and sufficient charging performance, fixing image bending strength, wide fixable temperature range, and high It is an object of the present invention to provide a toner having image stackability.

The present invention is a toner having a toner particle having a core containing a binder resin and a colorant, and a shell covering the core,
The binder resin is
i) a side chain crystalline resin;
ii) Melting point Tm is 50.0 ° C. or higher and 90.0 ° C. or lower,
The resin constituting the shell has a glass transition temperature Tg of 50.0 ° C. or higher and (Tm + 35.0) ° C. or lower,
The toner is
i) The storage elastic modulus G ′ (Tm + 10.0) at a temperature Tm + 10.0 ° C. is 1.0 × 10 ³ Pa or more and 1.0 × 10 ⁵ Pa or less,
ii) The ratio G ′ (Tm + 10.0) / G ′ (Tm + 50.0) of the storage elastic modulus G ′ (Tm + 50.0) and the G ′ (Tm + 10.0) at a temperature Tm + 50.0 ° C. is 10.0 or less. Is,
This invention relates to a toner.

  According to the present invention, it is possible to provide a toner that has both low-temperature fixability and heat-resistant storage stability and has sufficient charging performance, bending strength of a fixed image, a wide fixable temperature range, and high image stackability. Can do.

  The toner of the present invention is a toner having toner particles having a core-shell structure. The inventors of the present invention have a melting point of a binder resin that is a crystalline resin forming a core and a resin (shell resin) of a shell. The inventors have found that a desired effect can be obtained by controlling the glass transition temperature (Tg) and the viscoelasticity of the toner, and have reached the present invention.

  In the fixing process, since it is subjected to high-speed shearing, it is considered that the melted binder resin is impregnated into the softened shell resin and the main chains of both are intertwined. Then, after passing through the fixing roller, the fixed image is rapidly cooled to room temperature. At this time, if the Tg of the shell is controlled to be close to the Tm of the crystalline resin, the solidification of both occurs substantially simultaneously and rapidly, and the main chains of the shell resin and the binder resin are solidified while being entangled with each other. Therefore, the fragility of the fixed image is improved. Further, when the binder resin is a side chain crystalline resin, even when the main chain is entangled, the side chain portion can be crystallized, so that a decrease in crystallinity is suppressed. Thereby, it is considered that both low-temperature fixability and heat-resistant storage stability can be maintained. Moreover, since the glass transition temperature fall of surrounding shell resin can be suppressed to the minimum, it is thought that favorable image stacking property is obtained.

  The Tm of the binder resin constituting the core and the Tg of the resin constituting the shell will be described in detail.

  In the toner of the present invention, the glass transition temperature Tg of the resin constituting the shell needs to be 50.0 ° C. or higher and Tm + 35.0 ° C. or lower (Tm is the melting point of the binder resin). More preferably, it is 50.0 ° C. or higher and Tm + 10.0 ° C. or lower.

  When Tg is less than 50.0 ° C., the heat resistant storage stability of the toner is lowered. When Tg is larger than Tm + 35.0 ° C., the timing of melting the binder resin and softening of the shell resin is shifted, so that the temperature at which the main chain is entangled becomes high and the low-temperature fixability is insufficient. In addition, since the solidification of the two is not simultaneous, the main chain is easily entangled during cooling, the fixing strength is weakened, and the fixed image is peeled off when it is bent. The Tg can be controlled by the composition of the shell resin.

  In the present invention, a part of the shell resin in the toner can be extracted by, for example, the following method as a CHX insoluble component in the THF soluble component of the toner.

  The toner and THF are mixed at a concentration of 450 mg / ml, and shaken well at room temperature for 10 hours until the sample is no longer united, and the THF and sample are mixed well, and then allowed to stand for 7 days. Thereafter, the lysate is separated into a supernatant and a sediment by centrifuging at 15000 r / min for 60 minutes in a 10 ° C. environment using a cooling high-speed centrifuge (for example, H-9R (manufactured by Kokusan Co., Ltd.)). Collect the supernatant. Further, the supernatant liquid is reduced by 50% while bubbling the supernatant liquid with nitrogen gas to produce a concentrated liquid [X].

  Thereafter, 5 ml of the concentrated solution is added to 100 ml of CHX to produce insoluble matter. The liquid in which insoluble matter is generated is centrifuged for 60 minutes at 15000 r / min in a 10 ° C. environment using a cooling high-speed centrifuge (for example, H-9R (manufactured by Kokusan Co., Ltd.)). And the supernatant liquid is removed.

  After the removed precipitate was allowed to stand at room temperature for 24 hours, the solvent was removed in a vacuum dryer (40 ° C.) for 24 hours, THF was removed, and insoluble matter in CHX in THF-soluble matter. Collect the resulting ingredients.

  The Tg can be calculated by measuring the DSC of the CHX insoluble matter. In the reversible specific heat change curve of the CHX insoluble matter, the intersection point between the baseline halfway line before and after the specific heat change and the differential heat curve is defined as Tg. The DSC measurement method will be described later.

  In the present invention, the binder resin needs to be side chain crystalline. The side chain crystalline resin is a resin having a side chain that is an aliphatic hydrocarbon and / or an aromatic hydrocarbon with respect to the skeleton (main chain) of the organic structure, and has a crystal structure between the side chains. It is a resin having a structure that can The main chain crystalline resin typified by crystalline polyester is crystallized by folding the main chain, whereas the side chain crystalline resin is considered to be crystallized by one molecule side chain. Therefore, it can be crystallized even in a very narrow region, and it is considered that the crystallinity is less likely to decrease due to the surrounding environment than the main chain crystalline resin. Therefore, it is considered that by using a side chain crystalline resin as the binder resin, it is possible to obtain a toner having better sharp melt properties and having both low-temperature fixability and heat-resistant storage stability.

  When a main chain crystalline resin is used as the binder resin, folding is hindered due to the entanglement of the main chain, the crystallinity is lowered, and the glass transition temperature of the shell resin is lowered. May be reduced.

  In the present invention, the melting point Tm of the binder resin needs to be 50.0 ° C. or higher and 90.0 ° C. or lower. More preferably, it is 50.0 ° C. or higher and 80.0 ° C. or lower. If the Tm is less than 50.0 ° C, the heat resistant storage stability is lowered, and if it is greater than 90.0 ° C, it is insufficient from the viewpoint of low-temperature fixability. The melting point Tm can be controlled by the monomer type and molecular weight of the binder resin.

  Since the binder resin according to the present invention is a crystalline resin and hardly dissolves in THF, the melting point Tm of the binder resin can be calculated by measuring the differential scanning calorific value of the THF-insoluble matter in the extraction operation. The maximum endothermic peak temperature of the temperature-endothermic curve obtained by differential scanning calorimetry (DSC measurement) of the THF-insoluble matter is defined as Tm. The DSC measurement method will be described later.

Further, the storage elastic modulus G ′ of the toner needs to satisfy the following regulations.
The storage elastic modulus G ′ (Tm + 10.0) of the toner at Tm + 10.0 ° C. is 1.0 × 10 ³ Pa or more and 1.0 × 10 ⁵ Pa or less, and the storage elastic modulus of the toner at Tm + 50.0 ° C. The ratio of G ′ (Tm + 50.0) to G ′ (Tm + 10.0), G ′ (Tm + 10.0) / G ′ (Tm + 50.0) is 10.0 or less. In a toner having a melting point Tm of not less than 50.0 ° C. and not more than 90.0 ° C., the storage elastic modulus satisfies this rule, so that both low temperature fixability and a wide fixable temperature range can be achieved. If G ′ (Tm + 10.0) is less than 1.0 × 10 ³ , the melt viscosity of the toner is too low, and the phenomenon that the melted toner does not release from the fixing roller (hot offset) may occur. On the other hand, if G ′ (Tm + 10.0) is larger than 1.0 × 10 ⁵ , the toner is not sufficiently softened, which is insufficient in terms of low-temperature fixability. Further, when G ′ (Tm + 10.0) / G ′ (Tm + 50.0) is larger than 10.0, the viscosity decrease after the toner is melted is too large, and the fixable temperature region may decrease. The G ′ can be controlled by adding a polyfunctional monomer or comonomer to the monomer of the side chain crystalline resin that is a binder resin, but it is preferable to use a polyfunctional monomer from the viewpoint of lowering the crystallinity. A method for measuring the storage elastic modulus G ′ will be described later.

  The side chain crystalline resin as the binder resin is not particularly limited as long as it is a resin having a crystalline functional group in the side chain. For example, α-olefin resin, alkyl acrylate resin, alkyl methacrylate resin, alkyl ethylene oxide resin, siloxane resin, acrylamide resin, and the like can be used.

  Among these, the effects of the present invention are more easily exhibited by having a partial structure represented by the following formula.

(Wherein R1 is an alkyl group having 18 to 34 carbon atoms, and R2 is hydrogen or a methyl group.)

This component is preferable because the degree of crystallinity hardly decreases even when viscoelasticity control is performed. The chain length of the alkyl part of the component is preferably _C18 or more and _C34 or less from the viewpoint of controlling the melting point.

  The average film thickness of the shell in the toner of the present invention is preferably 3.0 nm or more and 500.0 nm or less from the viewpoint of the balance between the bending strength of the fixed image and the fixing inhibition. When the average film thickness of the shell is 3.0 nm or more and 500.0 nm or less, the peeling resistance at the time of folding of the fixed image due to the entanglement of the main chain of the shell resin and the binder resin is improved, and the fixing with the shell resin is performed. There is little inhibition. Moreover, when the film thickness of the shell is within the above range, the core can be sufficiently covered, and the chargeability can be improved. The method for calculating the shell average film thickness will be described later.

  Further, the SP value (SP1) of the shell resin is larger than the SP value (SP2) of the binder resin, and the difference between the two is preferably 0.5 or more and 2.0 or less. Since SP1 is larger than SP2, a clearer core-shell structure can be obtained. Further, when the difference between SP1 and SP2 is 0.5 or more, a decrease in the glass transition temperature of the component derived from the shell resin in the image after fixing can be suppressed, and the image stackability is improved. Further, when the difference between the two is 2.0 or less, the melted binder resin is easily impregnated by the softened shell resin, and the entanglement of the main chain is promoted, so that the bending strength of the fixed image is improved. The SP value calculation method will be described later.

  In the present invention, the half-value width of the endothermic peak at Tm of the DSC curve of the toner is preferably 8.0 ° C. or less. This half-value width is considered to have a correlation with the crystallinity of the toner, and the smaller the half-value width, the higher the crystallinity. If the half-value width is 8.0 ° C. or less, the sharp melt property of the crystalline resin is further increased. The half width can be calculated by measuring the DSC of the toner. The specific heat change curve of the toner was measured, and the temperature width of the Tm endothermic peak showing a value half the peak height from the base line was defined as the half width. The DSC measurement method will be described later.

  In the present invention, the toner production method is not particularly limited. That is, a known toner production method such as a pulverization method, a dissolution suspension method, an emulsion aggregation method, or a suspension polymerization method can be used. Among them, a production method in which particles are formed in an aqueous medium is preferable from the viewpoint of uniformly distributing the shell resin on the surface and obtaining a clear core-shell structure. In particular, the suspension polymerization method is preferred from the viewpoint of reducing the amount of solvent used and the number of steps.

  Hereinafter, a specific method for producing toner particles when the suspension polymerization method is used will be described. However, as described above, the present invention is not limited to the suspension polymerization method.

  First, a monomer composition containing a monomer having a crystallizable functional group that becomes a binder resin for toner particles, a shell resin, and other toner compositions are dissolved or dispersed in a solvent.

  Next, the solution or dispersion is put into an aqueous medium containing a dispersion stabilizer prepared in advance and suspended using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser. Do.

  The polymerization initiator may be mixed with other additives when preparing the polymerizable monomer composition, or may be mixed into the polymerizable monomer composition just before being suspended in the aqueous medium. Good. Moreover, it can also be added in the state melt | dissolved in the polymerizable monomer or other solvent as needed during granulation or after granulation completion, ie, just before starting a polymerization reaction.

  The suspension after granulation is heated, and the polymerization reaction is carried out with stirring so that the particles of the polymerizable monomer composition in the suspension maintain the particle state and the particles do not float or settle. To complete toner particles. Thereafter, the suspension is cooled, washed as necessary, and dried and classified by various methods to obtain toner particles.

  When the toner suspension is cooled, by slowly cooling the toner suspension, the elimination of the shell resin by the side chain crystalline resin as the binder resin is promoted, and a clear core-shell structure can be obtained.

  In the case of suspension polymerization, the above-described shell film thickness can be controlled by the amount of shell resin introduced. Further, the SP value SP1 of the shell resin can be controlled by changing the composition of the monomer constituting the shell resin. The SP value SP2 of the binder resin can also be controlled by changing the monomer composition constituting the binder resin. However, when a monomer having no crystallizable portion is introduced, the half-value width of the endothermic peak at Tm of the toner is Care is required because it tends to spread. As the monomer having a long-chain alkyl group for obtaining a side-chain crystalline resin having a partial structure represented by the above formula, known monomers can be used. Specific examples include long-chain alkyl acrylates or long-chain alkyl methacrylates such as palmityl acrylate, stearyl acrylate, behenyl acrylate, and tetratriacontyl acrylate. A plurality of such monomers may be used or may be copolymerized.

  In addition, the binder resin may copolymerize a monomer having two or more functional groups (polyfunctional monomer). As the polyfunctional monomer, a compound having two or more polymerizable double bonds is mainly used, and examples thereof include the following. Aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; Carboxylic acid esters having two double bonds such as ethylene glycol diacrylate; Divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide, and divinyl sulfone; Three or more vinyls A compound having a group.

  Further, a comonomer may be further copolymerized with the binder resin. Comonomers to be copolymerized include styrene and derivatives thereof such as styrene and o-methylstyrene; ethylene unsaturated monoolefins such as ethylene and propylene; vinyl halides such as vinyl chloride and vinyl bromide; and vinyl acetate. Vinyl ester acids; acrylic acid esters such as acrylic acid-n-butyl and acrylic acid-2-ethylhexyl; methacrylic acid esters obtained by changing the acrylic acid of the acrylic acid esters to methacrylic acid; dimethylaminoethyl methacrylate, diethylamino methacrylate Methacrylic acid aminoesters such as ethyl; Vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; Vinyl ketones such as vinyl methyl ketone; N-vinyl compounds such as N-vinyl pyrrole; Vinyl naphthalenes; Nitriles, such as acrylic acid or methacrylic acid derivatives of the main acrylamide, acrylic acid and methacrylic acid. In addition, you may use a comonomer in combination of 2 or more type as needed.

  The shell resin in the present invention is not particularly limited as long as it can be used as a binder resin for toner, and vinyl resins, polyester resins, epoxy resins, urethane resins, and the like can be used. Among these, vinyl resins and polyester resins are preferable from the viewpoint of electrophotographic characteristics.

  As the vinyl monomer, a polymer obtained by polymerizing a known radical polymerizable monomer can be used. Specific examples of the radical polymerizable monomer include monomers exemplified as comonomers that can be used in the binder resin. In addition, you may use a radically polymerizable monomer in combination of 2 or more type as needed.

  The polyester resin can be obtained by reacting a divalent or higher polyvalent carboxylic acid with a polyhydric alcohol.

  As a polyhydric alcohol monomer for obtaining such a polyester resin, a known alcohol monomer can be used. Specifically, the following can be used. Alcohol monomers such as ethylene glycol, diethylene glycol and 1,2-propylene glycol, and divalent alcohols such as polyoxyethylenated bisphenol A. Aromatic alcohols such as 1,3,5-trihydroxymethylbenzene, and trivalent alcohols such as pentaerythritol.

  A known carboxylic acid monomer can be used as the polyvalent carboxylic acid monomer for obtaining such a polyester resin. Specifically, for example, the following can be used. Dicarboxylic acids such as sebacic acid oxalate and acid anhydrides or lower alkyl esters thereof; trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, pyromellitic acid, 1, Trivalent or higher polyvalent carboxylic acids such as 2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, and acid anhydrides thereof Product or lower alkyl ester.

  The polyester resin that can be used in the present invention can be produced by a known polyester synthesis method. For example, after a dicarboxylic acid component and a dialcohol component are subjected to esterification reaction or transesterification reaction, reduced pressure or nitrogen gas is introduced and polycondensation reaction is performed according to a conventional method to obtain a polyester resin.

  In the case of esterification, a usual esterification catalyst or ester such as sulfuric acid, titanium butoxide, dibutyltin oxide, manganese acetate, tetrabutyl titanate, tin acetate, zinc acetate, tin disulfide, antimony trioxide, germanium oxide, etc. Exchange catalysts can be used. The reaction temperature and the amount of catalyst are not particularly limited, and may be arbitrarily selected as necessary.

  Further, the acid value of the polyester resin can be controlled and controlled by sealing the carboxyl group at the end of the polymer.

  Monocarboxylic acid and monoalcohol can be used for end-capping. Examples of monocarboxylic acids include acrylic acid, benzoic acid, naphthalenecarboxylic acid, salicylic acid, 4-methylbenzoic acid, phenoxyacetic acid, biphenylcarboxylic acid, acetic acid, propionic acid, butyric acid, octanoic acid, decanoic acid, dodecanoic acid, and stearic acid. And monocarboxylic acids such as Moreover, methanol, ethanol, propanol, isopropanol, butanol, and higher alcohol can be used as alcohol.

  The toner of the present invention contains a colorant as an essential component in order to impart coloring power. Known colorants such as various conventionally known dyes and pigments can be used. As the black colorant, carbon black, a magnetic material, or a yellow / magenta / cyan colorant shown below and a color toned to black are used. As the colorant for yellow toner, magenta toner, and cyan toner, for example, the following colorants can be used.

  As the yellow colorant, compounds represented by monoazo compounds, disazo compounds, condensed azo compounds, isoindolinone compounds, azo metal complex methine compounds, and allylamide compounds are used as pigments. Specifically, C.I. I. Pigment yellow 74, 93, 95, 109, 111, 128, 155, 174, 180, 185.

  Examples of the magenta colorant include monoazo compounds, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacdrine 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, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254, 269, C.I. I. And CI Pigment Bio Red 19.

  As the cyan colorant, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds can be used. Specifically, C.I. I. Pigment blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66.

  The toner of the present invention may contain a releasing agent for imparting releasability. There is no restriction | limiting in particular as a mold release agent used for this invention, A well-known thing can be utilized. Specific examples include the following. Low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, paraffin wax, aliphatic hydrocarbon wax such as Fischer-Tropsch wax; oxide of aliphatic hydrocarbon wax such as oxidized polyethylene wax or block copolymer thereof; Waxes mainly composed of fatty acid esters such as waxes, sazol waxes, ester waxes, and montanic acid ester waxes; those obtained by partially or fully deoxidizing fatty acid esters such as deoxidized carnauba wax; aliphatic hydrocarbon waxes Waxes grafted with vinyl monomers such as styrene and acrylic acid; partially esterified products of fatty acids and polyhydric alcohols such as behenic acid monoglyceride; And methyl ester compounds having a Rokishiru group.

  As the polymerization initiator that can be used in the present invention, various substances such as a peroxide polymerization initiator and an azo polymerization initiator can be used. Examples of the peroxide polymerization initiator that can be used include peroxyesters, peroxydicarbonates, dialkyl peroxides, peroxyketals, ketone peroxides, hydroperoxides, and diacyl peroxides. Examples of the inorganic system include persulfate and hydrogen peroxide. Specifically, t-butyl peroxyacetate, t-butyl peroxypivalate, t-butyl peroxyisobutyrate, t-hexyl peroxyacetate, t-hexyl peroxypivalate, t-hexyperoxy Peroxyesters such as isobutyrate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy 2-ethylhexyl monocarbonate; diacyl peroxides such as benzoyl peroxide; peroxydicarbonates such as diisopropyl peroxydicarbonate; Peroxyketals such as 1,1-di-t-hexylperoxycyclohexane; dialkyl peroxides such as di-t-butyl peroxide; and others such as t-butyl peroxyallyl monocarbonate It is. Examples of the azo polymerization initiator that can be used include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane- 1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile, dimethyl-2,2′-azobis (2-methylpropionate), etc. Illustrated. If necessary, two or more of these polymerization initiators can be used simultaneously.

  The toner particles of the present invention may use a charge control agent. Among them, it is preferable to use a charge control agent that controls the toner particles to be negatively charged. Examples of the charge control agent include the following.

  Organometallic compound, chelate compound, monoazo metal compound, acetylacetone metal compound, urea derivative, metal-containing salicylic acid compound, metal-containing naphthoic acid compound, quaternary ammonium salt, calixarene, silicon compound, nonmetal carboxylic acid compound and derivatives thereof Is mentioned. A sulfonic acid resin having a sulfonic acid group, a sulfonic acid group, or a sulfonic acid ester group can be preferably used.

  Further, the toner particles of the present invention contain a magnetic material and can be used as a magnetic toner. In this case, the magnetic material can also serve as a colorant. In the present invention, examples of the magnetic material include iron oxides such as magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel. Or alloys of these metals with metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium and mixtures thereof. .

  In order to improve the image quality, it is preferable that a fluidity improver is externally added to the toner of the present invention. As the fluidity improver, inorganic fine powders such as silicate fine powder, titanium oxide, and aluminum oxide are preferably used. These inorganic fine powders are preferably hydrophobized with a hydrophobizing agent such as a silane coupling agent, silicone oil or a mixture thereof. Furthermore, in the toner of the present invention, an external additive other than the fluidity improver may be mixed with the toner particles as necessary.

  The toner of the present invention can be used as it is as a one-component developer or as a two-component developer by mixing with a magnetic carrier.

  Hereinafter, a method for measuring physical properties of the toner of the present invention will be described.

(1) Method of Differential Scanning Calorimetry (DSC Measurement) of Resin and Toner Melting point, half-value width, and glass transition temperature of the resin are determined by ASTM D3418-82 using a differential scanning calorimeter “Q1000” (TA Instruments). Measure accordingly. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium. Specifically, 3 mg of the sample to be measured is precisely weighed and placed in an aluminum pan. Using an empty aluminum pan as a reference, modulation measurement is performed in a measurement range between 20 ° C. and 140 ° C. with a temperature increase rate of 1 ° C./min and an amplitude temperature range of ± 0.318 ° C./min. In this temperature raising process, a specific heat change is obtained in the temperature range of 20 ° C to 140 ° C. From the temperature-endothermic curve obtained by differential scanning calorimetry, the above-described Tg, Tm, and half width were calculated.

(2) Measuring method of storage elastic modulus G ′ of toner The storage elastic modulus G ′ of the toner at Tm + 10.0 ° C. (Tm + 10.0) in the present invention and the storage elastic modulus G ′ of the toner at the melting point Tm + 50.0 ° C. (Tm + 50.0) is measured by the following method.

  As a measuring apparatus, a rotating plate type rheometer “ARES” (manufactured by TA INSTRUMENTS) is used. As a measurement sample, a sample obtained by press molding a toner into a disk shape having a diameter of 8.0 mm and a thickness of 2.0 ± 0.3 mm using a tablet molding machine in an environment of 25 ° C. is used.

  The sample is mounted on a parallel plate, heated from room temperature (25.0 ° C.) to Tm + 5.0 ° C. to adjust the shape of the sample, then cooled to the measurement start temperature of viscoelasticity, and measurement is started. At this time, it is important to set the sample so that the initial normal force becomes zero.

The measurement is performed under the following conditions.
1) Use a parallel plate with a diameter of 8.0 mm.
2) The frequency (Frequency) is 1.0 Hz.
3) The applied strain initial value (Strain) is set to 0.1%.
4) Measurement is performed at a rate of temperature rise (Ramp Rate) of 2.0 ° C./min between 0 ° C. and 150 ° C. In the measurement, the following automatic adjustment mode setting conditions are used. Measurement is performed in an automatic strain adjustment mode (Auto Strain).
5) Set Max Applied Strain to 20.0%.
6) The maximum torque (Max Allowed Torque) is set to 200.0 g · cm, and the minimum torque (Min Allowed Torque) is set to 0.2 g · cm.
7) Set the distortion adjustment (Strain Adjustment) to 20.0% of Current Strain.

  When the storage elastic modulus G ′ is measured in the temperature range of 30 ° C. or higher and 200 ° C. or lower by the above method, the storage elastic modulus G ′ at Tm + 10.0 ° C. is expressed as G ′ (Tm + 10.0), Tm + 50.0. The value of the storage elastic modulus G ′ at ° C. was defined as G ′ (Tm + 50.0).

(3) Method for calculating average film thickness of shell The average film thickness of the shell can be determined by measuring the cross-sectional shape of the toner particles. As a specific method for measuring the shape of the cross section of the toner particles, first, the toner particles are sufficiently dispersed in a photocurable epoxy resin, and then the epoxy resin is cured by irradiation with ultraviolet rays. The obtained cured product is cut using a microtome equipped with diamond teeth to produce a flaky sample. After the sample is dyed with ruthenium tetroxide, the tomographic morphology of the toner is observed under the condition of an acceleration voltage of 120 kV using a transmission electron microscope (TEM) (H7500 manufactured by HITACHI). In the observation method described above, the amorphous part of the toner particles is strongly dyed with ruthenium tetroxide. As a result, the shell portion mainly composed of the amorphous resin in the present invention is stained, and the core portion mainly composed of the unstained side chain crystalline resin can be observed as contrast. The observation magnification was 20000 times.

  Moreover, the image obtained by the said photography was read at 600 dpi via the interface, and introduced into an image analysis device WinROOFVersion 5.0 (manufactured by Microsoft Corporation-Mitani Corporation).

Based on the obtained TEM photograph, when the surfaces of the toner particles are connected by a straight line in the cross section of the toner particles, the longest straight line is defined as the major axis of the toner particle, and the length is defined as a major axis diameter R (nm). To do. When the length between the two core / shell interfaces on the major axis was r (nm), (R−r) / 2 (nm) was taken as the shell film thickness.
Further, this measurement was performed for 100 toners, and the average value was defined as the shell average film thickness.

(4) SP Value Calculation Method of Binder Resin and Shell Resin In the present invention, the SP value (SP2) of the binder resin and the SP value (SP1) of the shell resin are as follows according to the calculation method proposed by Fedors: I asked for it.

  First, the SP value of a repeating unit constituting a binder resin or a resin (hereinafter also referred to as a resin or the like) is obtained as follows. Here, the binder resin or the repeating unit constituting the resin means that when the binder resin or resin is a vinyl resin (when a polymer constituting the resin is generated by a polymerization reaction of a vinyl monomer), It means a molecular structure in which a double bond of a vinyl monomer is cleaved by polymerization.

For example, when calculating the SP value (σ _m ) of a repeating unit, “Polym. Eng. Sci., 14 (2), 147-154 (1974) is applied to the atom or atomic group in the molecular structure of the repeating unit. The evaporation energy (Δei) (cal / mol) and the molar volume (Δvi) (cm ³ / mol) are determined from the table described in “)” and calculated from the following formula (1).
Formula (1): σ _m = (ΣΔei / ΣΔvi) ^1/2

SP value ((sigma) _p ) of resin etc. calculates | requires the evaporation energy ((DELTA) ei) and molar volume ((DELTA) vi) of the repeating unit which comprises the resin for every repeating unit, The molar ratio (j) in resin of each repeating unit in resin Is calculated by dividing the sum of the evaporation energies of each repeating unit by the sum of the molar volumes, and calculating from the following equation (2).
Formula (2): σ _p = {(Σj × ΣΔei) / (Σj × ΣΔvi)} ^1/2

For example, assuming that the resin is composed of two types of repeating units of X and Y, the composition ratio of each repeating unit is Wx, Wy (mass%), the molecular weight is Mx, My, and the evaporation energy is Δei (X ), Δei (Y), and molar volume Δvi (X), Δvi (Y), the molar ratio (j) of each repeating unit is Wx / Mx, Wy / My, and the solubility parameter value (σ _{p of} this resin) ) Is represented by the following formula (3).
Formula (3): σ _p = [{(Wx / Mx) × Δei (X) + Wy / My × Δei (Y)} / {(Wx / Mx) × Δvi (X) + Wy / My × Δvi (Y)} ] ^1/2

When two or more kinds of resins are further mixed, the SP value (σ _M ) of the mixture is calculated as the product of the mass composition ratio (Wi) of the mixture and the SP value (σi) of each resin, and the following formula (4 )become that way.
Formula (4): σ _M = Σ (Wi × σi)
(5) Calculation of toner peak molecular weight (Mp) The molecular weight distribution of the toner in the present invention is measured by gel permeation chromatography (GPC) as follows.

First, the toner is dissolved in chloroform over 24 hours at room temperature. Then, the obtained solution is filtered through a solvent-resistant membrane filter “Mysholy disk” (manufactured by Tosoh Corporation) having a pore diameter of 0.5 μm to obtain a sample solution. The sample solution is adjusted so that the concentration of the component soluble in chloroform is 0.5% by mass. Using this sample solution, measurement is performed under the following conditions.
Apparatus: HLC8220 GPC (detector: RI, UV) (manufactured by Tosoh Corporation)
Column: TSKgelG4000HXL, TSKgelG3000HXL, TSKgelG2000HXL (manufactured by Tosoh Corporation)
Eluent: Chloroform Flow rate: 1.0 ml / min
Oven temperature: 45.0 ° C
Sample injection volume: 0.10 ml

  In calculating the molecular weight of the sample, standard polystyrene resin (for example, trade name “TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F— 10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500 ", manufactured by Tosoh Corporation) are used.

(6) Measurement of volume-based median diameter of resin fine particles The volume-based median diameter (D50) of resin fine particles used in the present invention is measured according to JIS Z8825-1 (2001). Specifically, it is as follows.
As a measuring device, a laser diffraction / scattering particle size distribution measuring device “LA-920” (manufactured by Horiba, Ltd.) is used. The dedicated software “HORIBA LA-920 for Windows WET (LA-920) Ver. 2.02” attached to LA-920 is used for setting the measurement conditions and analyzing the measurement data. As the measurement solvent, ion-exchanged water from which impure solids are removed in advance is used.

The measurement procedure is as follows.
1) Attach the batch type cell holder to LA-920.
2) Put a predetermined amount of ion-exchanged water in a batch cell and set the batch cell in a batch cell holder.
3) Stir the inside of the batch cell using a dedicated stirrer tip.
4) Press the “refractive index” button on the “display condition setting” screen and select the file “110A000I” (relative refractive index 1.10).
5) In the “display condition setting” screen, the particle diameter standard is set as the volume standard.
6) After performing warm-up operation for 1 hour or more, optical axis adjustment, optical axis fine adjustment, and blank measurement are performed.
7) Put about 60 ml of ion-exchanged water in a glass 100 ml flat bottom beaker. Among them, as a dispersant, “Contaminone N” (a nonionic surfactant, an anionic surfactant, a 10% by weight aqueous solution of a neutral detergent for washing a pH 7 precision measuring instrument comprising an organic builder, Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting the product (manufactured) with ion exchange water about 3 times by mass is added.
8) Two oscillators having an oscillation frequency of 50 kHz are built in with a phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.
9) The beaker of 7) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the aqueous solution in a beaker may become the maximum.
10) In a state where the aqueous solution in the beaker of 9) is irradiated with ultrasonic waves, about 1 mg of fatty acid metal salt is added to the aqueous solution in the beaker little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In this case, the fatty acid metal salt may solidify and float on the liquid surface. In this case, ultrasonic dispersion is performed for 60 seconds after the mass is submerged by shaking the beaker. Moreover, in ultrasonic dispersion, it adjusts suitably so that the water temperature of a water tank may become 10 to 40 degreeC.
11) The aqueous solution in which the fatty acid metal salt prepared in 10) is dispersed is immediately added little by little to the batch type cell while taking care not to introduce bubbles, and the transmittance of the tungsten lamp becomes 90% to 95%. Adjust as follows. Then, the particle size distribution is measured. The volume-based median diameter (D50) is calculated based on the obtained volume-based particle size distribution data.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. All parts used in the examples indicate parts by mass.

<Manufacture of shell resin 1>
The following materials were put in a reaction vessel equipped with a reflux condenser, a stirrer, and a nitrogen inlet tube under a nitrogen atmosphere.
-Toluene 100.0 parts-Styrene (St) 84.5 parts-N-butyl acrylate (BA) 11.3 parts-Methyl methacrylate (MMA) 2.5 parts-Methacrylic acid (MAA) 1.7 parts- t-Butyl peroxypivalate 3.0 parts

  The inside of the container was stirred at 200 rpm, heated to 70 ° C. and stirred for 10 hours. Furthermore, it heated at 100 degreeC and superposed | polymerized for 6 hours. Thereafter, the solvent was distilled off to obtain shell resin 1. Shell resin 1 had a Tg of 71 ° C., an SP value of 9.9, and a peak molecular weight (Mp) of 15000.

<Manufacture of shell resins 2 to 9>
In the production of shell resin 1, the reaction was carried out in the same manner except that the amount of monomer charged was changed as shown in Table 1, and shell resins 2 to 9 were obtained. Table 1 shows the Tg, SP value, and Mp of each shell resin.

In Table 1, St represents styrene, BA represents n-butyl acrylate, MMA represents methyl methacrylate, AcMO represents acryloylmorpholine, and MAA represents methacrylic acid.

<Manufacture of shell resin 10>
The following materials were charged under a nitrogen atmosphere in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe.
-230.0 parts of terephthalic acid-690.0 parts of bisphenol A-propylene oxide 2 mole adduct-120.0 parts of benzoic acid-3.0 parts of titanium diisopropoxy bistriethanolamate

  The reaction was carried out for 5 hours while distilling off the water produced at 210 ° C., then the pressure was reduced to 5 to 20 mmHg, and the reaction was further carried out for 5 hours. Subsequently, 20.0 parts of trimellitic anhydride was added and reacted at normal pressure for 1 hour. The obtained shell resin 8 had a Tg of 62 ° C., an SP value of 10.9, and a peak molecular weight (Mp) of 5000.

<Manufacture of shell resin 11>
The following materials were charged under a nitrogen atmosphere in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe.
・ 2,2′-bis (4-hydroxycyclohexyl) propane 710.0 parts ・ Terephthalic acid 235.0 parts ・ Adipic acid 140.0 parts ・ Tetrabutoxy titanate 0.5 parts

  It was made to react for 12 hours, distilling off the water produced | generated at 180 degreeC. Subsequently, it was made to react for 4 hours, heating up gradually to 230 degreeC. Thereafter, the pressure was reduced to 5 to 20 mmHg, and the reaction was further continued for 5 hours. The obtained resin was designated as shell resin 9. The obtained shell resin 11 had a Tg of 65 ° C., an SP value of 11.1, and a peak molecular weight (Mp) of 6500.

<Manufacture of shell resin 12>
The following raw materials are put into a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, reacted at 220 ° C. under normal pressure for 15 hours, and further reacted for 0.5 hour under reduced pressure of 1.3 to 2.6 kPa. It was.
・ Terephthalic acid 210.0 parts ・ Isophthalic acid 210.0 parts ・ Bisphenol A-propylene oxide 2 mol adduct 1200.0 parts ・ Potassium oxalate titanate 0.3 parts

  Thereafter, the temperature was lowered to 180 ° C., 0.01 part of trimellitic anhydride was added, and the mixture was reacted at 180 ° C. for 1.5 hours to obtain shell resin 12. The obtained shell resin 10 had a Tg of 75 ° C., an SP value of 9.8, and a peak molecular weight (Mp) of 9000.

  The physical properties of the manufactured shell resins 10 to 12 are shown in Table 2.

<Manufacture of shell resin dispersion A>
The following raw materials were put in a reaction vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen introduction tube, and dissolved by heating to a temperature of 80 ° C.
-Shell resin 1 100.0 parts-Methyl ethyl ketone 45.0 parts-Tetrahydrofuran 45.0 parts-Diethylaminoethanol 1.0 part

  Next, under stirring, 300.0 parts of ion-exchanged water having a temperature of 80 ° C. is gently added to effect phase inversion emulsification, and the resulting aqueous dispersion is transferred to a distillation apparatus until the fraction temperature reaches 100 ° C. Distillation was performed.

  After cooling, ion-exchanged water was added to the obtained aqueous dispersion to adjust the shell resin concentration in the dispersion to 20%. This was designated as shell resin dispersion A. A part of the shell resin dispersion A was withdrawn, and the volume-based median diameter (D50) was measured and found to be 480 nm.

<Manufacture of shell resin dispersions B to D>
In the production of the shell resin dispersion A, phase inversion emulsification was performed in the same manner except that the amounts of the shell resin and diethylaminoethanol used were changed as shown in Table 3 to obtain shell resin dispersions B to D. The volume-based median diameter (D50) of the shell resin dispersion is shown in Table 3.

<Preparation of behenyl acrylate dispersion>
・ Behenyl acrylate 100.0 parts ・ 1,10-decanediol diacrylate 0.7 parts ・ t-butyl peroxypivalate 6.0 parts

  The above materials were mixed and dissolved, and 2.0 parts of a nonionic surfactant (Sanyo Kasei Co., Ltd .: Nonipol 400) and an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) ) Ion-exchanged water in which 1.0 part of ammonium persulfate was dissolved in 3.00.0 parts dissolved in 140.0 parts of ion-exchanged water, dispersed in a flask, emulsified, and slowly mixed for 10 minutes. 10.0 parts were charged. After carrying out nitrogen substitution, while stirring the inside of the flask, the contents were heated in an oil bath until the temperature reached 70 ° C., and emulsion polymerization was continued for 5 hours. After cooling, ion-exchanged water was added to the obtained water dispersion, and the resin concentration in the dispersion was adjusted to 20% to prepare a behenyl acrylate dispersion.

<Preparation of crystalline polyester dispersion>
(Preparation of crystalline polyester)
In a reaction apparatus equipped with a stirrer, a thermometer, and an outflow cooler, 49.5 parts of 1,10-dodecanedioic acid, 8.0 parts of isophthalic acid, 22.3 parts of 1,9-nonanediol, tetrabutyl titanate 0 0.03 part was added, and the reaction was performed at a temperature of 220 ° C. for 5 hours under a nitrogen atmosphere. Thereafter, the reaction vessel was further reacted under reduced pressure conditions of 0.7 to 2.6 kPa for 5 hours to obtain a crystalline polyester.

(Preparation of crystalline polyester dispersion)
100.0 parts of the crystalline polyester was put in 800.0 parts of distilled water, heated to 70 ° C., adjusted to pH 9.0 with ammonia, and an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: 0.4 parts of Neogen RK) was added, and the mixture was dispersed at 8000 rpm for 7 minutes with a homogenizer (IKA Japan Co., Ltd .: Ultra Turrax T50) while heating to 70 ° C. to obtain a crystalline polyester dispersion A.

<Preparation of colorant dispersion>
Pigment Blue 15: 3 70.0 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen) 3.0 parts Ion-exchanged water 400.0 parts After mixing and dissolving the above components Then, a colorant dispersion liquid A was obtained by dispersing using a homogenizer (manufactured by IKA: Ultra Turrax T50).

<Preparation of release agent dispersion>
Paraffin wax (Nippon Seiki: HNP-5 melting point 60 ° C.) 100.0 parts Anionic surfactant (Takemoto Yushi Co., Ltd .: Pionein A-45-D) 2.0 parts Ion-exchanged water: 500.0 Part After mixing and dissolving the above components, the mixture was dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), then dispersed with a pressure discharge type gorin homogenizer, and release agent fine particles (paraffin wax) were dispersed. A release agent dispersion A dispersed was obtained.

<Example 1>
(Preparation of toner particles 1)
-Behenyl acrylate (BeA) 100.0 parts (manufactured by Shin-Nakamura Chemical Co., Ltd .: NK ester A-BH)
・ 1,10-decanediol diacrylate (crosslinking agent) 0.7 part (manufactured by Shin-Nakamura Chemical Co., Ltd .: NK ester A-DOD-N)
Pigment Blue 15: 3 6.5 parts Aluminum salicylate compound 1.0 parts (Orient Chemical Co., Ltd .: Bontron E-88)
Release agent Paraffin wax 9.0 parts (Nippon Seiki: HNP-51, melting point 74 ° C.)
A mixture of monomers consisting of 10.0 parts of shell resin 1 and 100.0 parts of toluene was prepared. 15 mm zirconia beads were put into this, and dispersed for 2 hours using an attritor (manufactured by Mitsui Miike Chemical Co., Ltd.) to obtain a monomer composition.

  Moreover, 800 parts of ion-exchange water and 15.5 parts of tricalcium phosphate are added to a container equipped with a high-speed stirring device TK-Homomixer (made by Tokushu Kika Kogyo Co., Ltd.), and the rotational speed is adjusted to 15000 rpm. The dispersion medium was heated to 70 ° C.

  To the monomer composition, 6.0 parts of t-butyl peroxypivalate as a polymerization initiator was added, and this was put into the dispersion medium. The granulation process was performed for 20 minutes while maintaining 12000 revolutions / minute with the high-speed stirring device. Thereafter, the stirrer was changed from the high-speed stirrer to the propeller stirring blade, and polymerization was carried out for 10 hours while maintaining at 70 ° C. while stirring at 150 rpm, and then the solvent was removed at 95 ° C. for 5 hours.

  The obtained toner particle dispersion was cooled to 20 ° C., and diluted hydrochloric acid was added until the pH reached 1.5. Further, after sufficiently washing with ion-exchanged water, it was filtered and dried to obtain toner particles 1 containing polyacrylic acid behenyl as a binder resin. The molecular weight distribution of the toner particles 1 was measured, and the peak molecular weight Mp was calculated to be 56000.

(Preparation of Toner 1)
After the toner particles 1 are classified, 100.0 parts are weighed, and hydrophobic silica fine powder (primary particle size 12 nm, BET specific surface area 120 m ² / g, surface treatment agent: hexamethyldisilazane, silicone oil) is 1 0.0 part was added and mixed using a Henschel mixer (manufactured by Mitsui Miike Chemical Co., Ltd.) to obtain toner 1.

<Examples 2 to 8, 10, 12 to 16, Comparative Examples 1 to 3, 5 to 8>
In Example 1, the type of monomer used, the amount of crosslinking agent, the amorphous resin used, and the amount introduced were changed as shown in Table 4. Otherwise, toner particles and toner were obtained in the same manner as in Example 1. Note that BeA represents behenyl acrylate, MMA represents methyl methacrylate, AcA represents acrylic acid, St represents styrene, and BMA represents butyl methacrylate. Moreover, the ratio in the binder resin composition in a table | surface is a mass ratio.

<Example 9>
In Example 1, the shell resin was not charged at the time of polymerization, and the polymerization reaction was carried out with the types of monomers and the amount of crosslinking agent as shown in Table 5. After the completion of the polymerization, the obtained dispersion of resin particles was cooled, and ion exchange water was added to adjust the concentration of the resin particles in the dispersion to 20% to obtain a core particle dispersion.

  Next, 500.0 parts of the core particle dispersion (solid content 100.0 parts), shell resin dispersion A 225.0 parts (solid content 45.0 parts) and an anionic surfactant (trade name: Neogen SC) (Made by Daiichi Kogyo Seiyaku Co., Ltd.) 20.0 parts was added and heated to 71.0 ° C. which is the Tg of the shell resin. Further, sodium hydroxide was appropriately added to keep the pH in the system at 4.0 or lower, and maintained for 3 hours to fuse the aggregated particles. Thereafter, the mixture was cooled to 25 ° C., sufficiently washed with ion exchange water, filtered, dried, and classified to obtain toner particles 9.

<Example 11>
Toner particles and toner were obtained in the same manner as in Example 9, except that the resin fine particle dispersion used in Example 9 and the amount thereof were as shown in Table 5.

<Example 17>
-Behenyl acrylate dispersion 300.0 parts-Colorant dispersion 50.0 parts-Release agent particle dispersion 60.0 parts-Cationic surfactant 3.0 parts (Sanisol B50, manufactured by Kao Corporation)
・ Ion exchange water 500.0 parts

  The above components were mixed and dispersed in a round-bottomed stainless steel flask using a homogenizer (manufactured by IKA: Ultra Turrax T50) to prepare a mixed solution, which was then heated to 50 ° C. with stirring in an oil bath for heating. Holding at 30 ° C. for 30 minutes formed aggregated particles. Next, 6.0 parts of sodium dodecylbenzenesulfonate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) as an anionic surfactant was added to the aggregated particle dispersion and heated to 60 ° C. Further, sodium hydroxide was appropriately added to keep the pH in the system at 4.0 or lower, and maintained for 3 hours to fuse the aggregated particles. Thereafter, it was cooled to 45 ° C. at a descending rate of 1.0 ° C./min. Ion exchange water was added to the obtained dispersion to adjust the resin concentration in the dispersion to 20%, and a core particle dispersion was obtained.

After dropping 6 parts of a 10% aqueous solution of polyaluminum chloride into 500.0 parts of the core particle dispersion (solid content 100.0 parts), 50 parts of shell resin dispersion C (10.0 parts of solid content) was added and pH was adjusted. Was adjusted to 4 and stirring was continued for 30 minutes. The suspension was warmed to 71 ° C. and stirred for another 3 hours. Thereafter, the mixture was filtered, thoroughly washed with ion exchange water, and dried with a vacuum dryer to obtain toner particles 17.
Thereafter, a hydrophobic silica fine powder was externally added in the same manner as in Example 1 to obtain toner 17.

<Comparative example 4>
Toner particles and toner 21 were obtained in the same manner as in Example 17 except that the crystalline polyester dispersion and the shell resin dispersion D were used instead of the behenyl acrylate dispersion and the shell resin dispersion C.

  Table 6 shows the physical properties of each toner.

  The performance of each toner obtained in Examples 1 to 17 and Comparative Examples 1 to 9 was evaluated according to the following method.

<Fixability>
Using a commercially available color laser printer (Canon: LBP-5400), the toner in the cyan cartridge was taken out and filled with the toner, and the cartridge was installed in the cyan station. Next, an unfixed toner image (0.6 mg / cm ² ) of 2.0 cm in length and 15.0 cm in width is placed on the image receiving paper (Canon office planner 64 g / m ² ) from the upper end with respect to the sheet passing direction. It was formed in a 0.0 cm portion. Next, the fixing unit removed from a commercially available color laser printer (Canon: LBP-5400) was remodeled so that the fixing temperature, process speed and fixing linear pressure could be adjusted, and a fixing test for unfixed images was performed using this. It was.

  First, an unfixed image is fixed at each temperature while setting a process speed of 250 mm / s at a normal temperature and humidity, a fixing linear pressure of 14.0 kgf, an initial temperature of 80 ° C., and gradually increasing the set temperature by 5 ° C. I do.

(Minimum fixing temperature)
In the present invention, the temperature at which no cold offset occurs is defined as the minimum fixing temperature. The cold offset means that only a part of the toner that forms an image melts and adheres to the fixing roller, and the subsequent fixing sheet is contaminated. At this time, since the toner that has not adhered to the fixing roller is not melted, it is not fixed and easily disappears when rubbed with a finger. The evaluation criteria for the minimum fixing temperature are as follows.
A: Minimum fixing temperature is less than 90 ° C. (low temperature fixing performance is particularly excellent)
B: The minimum fixing temperature is 90 ° C. or higher and lower than 95 ° C. (low temperature fixing performance is good)
C: Minimum fixing temperature of 95 ° C. or higher and lower than 100 ° C. (low-temperature fixing performance is at a level where there is no problem)
D: Minimum fixing temperature is 100 ° C. or higher and lower than 110 ° C. (low temperature fixing performance is slightly inferior)
E: Minimum fixing temperature is 110 ° C. or higher (low temperature fixing performance is inferior)

(Folding strength of fixed image)
Further, when the fixed image fixed at the minimum fixing temperature + 20 ° C. is rubbed with sylbon paper (Oz Sangyo Co., Ltd .: DUPER K-3) applied with a load of 4.9 kPa (50 g / cm ² ) The density reduction rate before and after was taken as the bending strength of the fixed image. The evaluation criteria for the bending strength of the fixed image are as follows.
A: Density reduction rate is less than 5% (Folded strength of fixed image is particularly excellent)
B: The density reduction rate is 5% or more and less than 10% (the folding strength of the fixed image is excellent)
C: Density reduction rate is 10% or more and less than 15% (the bending strength of the fixed image is at a level where there is no problem)
D: Density reduction rate is 15% or more and less than 20% (fixed image has poor bending strength)
E: Density reduction rate is 20% or more (the folding strength of the fixed image is extremely inferior)

(Fixable area)
The maximum temperature at which no hot offset was observed under the same conditions was defined as the maximum fixing temperature, and the difference between the maximum fixing temperature and the minimum fixing temperature was determined as the fixable region. The evaluation criteria for the fixable area are as follows.
A: The temperature at which hot offset does not occur is equal to or higher than the temperature at the starting point on the low temperature side + 60 ° C. (the fixable region is particularly wide)
B: The temperature at which hot offset does not occur is the temperature at the low temperature side starting point + 50 ° C. or more and less than + 60 ° C. (the fixable area is wide).
C: The temperature at which hot offset does not occur is the temperature at the low temperature side starting point + 40 ° C. or more and less than + 50 ° C. (the fixable region is at a level where there is no problem)
D: Temperature at which hot offset does not occur is the temperature at the low temperature side starting point + 30 ° C. or higher and lower than + 40 ° C. (fixable area is slightly narrow)
E: Hot offset occurs in the temperature range below the temperature of the starting point on the low temperature side + 30 ° C. (the fixable area is narrow)

<Chargeability>
(Cover)
For toners 1 to 25, each toner and a magnetic fine particle-dispersed resin carrier (number average particle size 35 μm) surface-coated with a silicone resin are mixed so that the toner concentration is 8.0% by mass, and two-component development is performed. Agents 1 to 25 were prepared.

  450g of each two-component developer is allowed to stand for 7 days under high temperature and high humidity (30 ℃ / 80%), and then left for another 3 days under normal temperature and humidity (23 ℃ / 60%) to reset the triboelectric charge due to initial mixing. did. The images were evaluated for evaluation in a color copier CLC5500 remodeled machine (manufactured by Canon) in a room temperature and humidity environment (23 ° C./60%).

Each developer was charged into the developer unit, 10 solid white A4 images were output without preliminary rotation, and the reflectance of the solid white portion of the image was measured. Further, the reflectance of the unused paper was measured and subtracted from the reflectance of the solid white portion of the image to obtain the fog density. The average value of the fog density measured for the 10 images output was evaluated according to the following evaluation criteria. The reflectance was measured with TC-6DS (manufactured by Tokyo Denshoku).
A: The fog density is less than 0.6% (charging property is particularly excellent)
B: Fog density is less than 1.0% (excellent chargeability)
C: The fog density is less than 1.5% (good chargeability)
D: Fog density is less than 2.0% (chargeability is slightly inferior)
E: The fog density is 2.0% or more (poor chargeability)

<Heat resistant storage stability>
(blocking)
5 g of toner is weighed into a 100 ml capacity polycup and placed in a thermostatic chamber having an internal temperature of 50 ° C. and left to stand. Three days later, the polycup in the thermostatic chamber is taken out, and the state change of the toner inside is visually evaluated. Judgment criteria are as follows.
A: No change (especially excellent heat-resistant storage stability)
B: Slight agglomerates are formed, but they are loosened immediately (good heat-resistant storage stability)
C: Some agglomerates are formed, but they are loosened with a slight impact (the heat-resistant storage stability is at a level where there is no problem).
D: Agglomerates are formed and are not easily loosened (the heat-resistant storage stability is slightly inferior)
E: Completely agglomerates and hardens into a button shape (inferior heat-resistant storage stability)

(Image loadability)
The following evaluation was performed on the fixed image paper at a temperature 20 ° C. higher than the minimum fixing temperature. Place the fixed image paper face down on 500 sheets of unused paper (Canon Office Planner 64 g / m ² ), and then place 500 kinds of unused paper of the same type on the fixed image paper. The fixed image paper was sandwiched between the sheets. This was left still in the thermostat adjusted to 45 degreeC, and after taking out for 72 hours, it took out from the thermostat. Measure the reflectivity of the unused paper that was in contact with the fixed image paper, and subtract the reflectivity of the unused paper that was in contact with the image area. The color transfer of the image was measured. From this situation, the image stackability was evaluated according to the following criteria. The reflectance was measured with TC-6DS (manufactured by Tokyo Denshoku).
A: The density of the color-transferred portion is less than 0.5% (image stackability is particularly excellent).
B: The density of the color-transferred portion is less than 1.0% (excellence in image loading)
C: The density of the color-transferred portion is less than 2.0% (there is no practical problem with image stackability)
D: The density of the color-transferred portion is less than 4.0% (slightly inferior in image stackability)
E: The density of the color-transferred portion is 4.0% or more (inferior in image stackability)
The results are shown in Table 7.

  As described above, in a toner in which a core made of a crystalline resin is coated with a shell resin, a low-temperature fixing and a wide fixable region can be realized by using a side-chain crystalline resin as the crystalline resin and appropriately controlling viscoelasticity. I understood. In addition, by appropriately controlling the glass transition temperature of the shell resin, the crystalline resin and the shell resin are mixed at the time of fixing, so that a high fixing image bending strength is realized, and a toner having a high image loading property is obtained. I understood it.

  On the other hand, in the comparative example, when a crystalline resin that does not satisfy the requirements of the present invention is used, the fixable region becomes clogged or the low-temperature fixability is not sufficiently exhibited. Further, when a shell resin that does not satisfy the requirements of the present invention is used, the bending strength of the fixed image is lowered.

As described above, the toner of the present invention has both low-temperature fixability and heat-resistant storage stability, and has sufficient charging performance, bending strength of a fixed image, wide fixable temperature range, and high image stackability. It turns out that it can be provided.

Claims (6)

A toner having a toner particle having a core containing a binder resin and a colorant and a shell covering the core,
The binder resin is
i) a side chain crystalline resin;
ii) Melting point Tm is 50.0 ° C. or higher and 90.0 ° C. or lower,
The resin constituting the shell has a glass transition temperature Tg of 50.0 ° C. or higher and (Tm + 35.0) ° C. or lower,
The toner is
i) The storage elastic modulus G ′ (Tm + 10.0) at a temperature Tm + 10.0 ° C. is 1.0 × 10 ³ Pa or more and 1.0 × 10 ⁵ Pa or less,
ii) The ratio G ′ (Tm + 10.0) / G ′ (Tm + 50.0) of the storage elastic modulus G ′ (Tm + 50.0) and the G ′ (Tm + 10.0) at a temperature Tm + 50.0 ° C. is 10.0 or less. Is,
Toner characterized by the above. The toner according to claim 1, wherein the binder resin has a partial structure represented by Formula 1.

(Formula 1)
(Wherein R1 is an alkyl group having 18 to 34 carbon atoms, and R2 is hydrogen or a methyl group.)   The toner according to claim 1, wherein an average film thickness of the shell is 3.0 nm or more and 500.0 nm or less.   When the SP value of the resin constituting the shell is SP1, and the SP value of the binder resin is SP2, the difference (SP1-SP2) is 0.5 to 3.0. Item 4. The toner according to any one of Items 1 to 3.   5. The toner according to claim 1, wherein the toner has a full width at half maximum of 8.0 ° C. or less with respect to a main peak of a temperature-endothermic curve obtained by differential scanning calorimetry. Toner. 6. The toner according to claim 1, wherein the toner particles are polymerized toner particles produced by polymerizing a polymerizable monomer in an aqueous medium.