JP2006146056A - Toner for developing electrostatic charge image, and electrostatic charge image developer and image forming method using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for developing an electrostatic charge image capable of suppressing brightness unevenness and hot offset. <P>SOLUTION: The toner containing a binder resin, a colorant, and bi- or higher valent metals is characterized in that the base material liberation rate of the bi- or higher valent metals is &le;18% and the metal element liberation rate is &le;15%. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to an electrostatic image developing toner used for developing an electrostatic image in an electrophotographic apparatus using an electrophotographic process such as a copying machine, a printer, and a facsimile machine, and an electrostatic image development using the same. The present invention relates to an agent and an image forming method.

  A method for visualizing image information through an electrostatic charge image, such as electrophotography, is currently widely used in various fields. In the electrophotographic method, an electrostatic charge image is formed on the photoreceptor through a charging step, an exposure step, etc., and the electrostatic charge image is developed using a developer containing toner, and further, a transfer step and a fixing step. Etc., it is visualized as an image.

  As this developer, a two-component developer containing a toner and a carrier and a one-component developer containing a magnetic toner or a non-magnetic toner are known. The toner used for the developer is usually produced by a kneading and pulverizing method. In this kneading and pulverizing method, a thermoplastic resin or the like is melt-kneaded together with a pigment, a charge control agent, a release agent such as wax, and the like to prepare a melt-kneaded product, and then the melt-kneaded product is cooled and pulverized, Finally, a finely pulverized melt-kneaded product is classified to produce desired toner particles. In addition, inorganic fine particles and / or organic fine particles are added to the surface of the toner manufactured by the kneading and pulverizing method, as necessary, for the purpose of improving fluidity and cleaning properties.

The toner produced by the kneading and pulverizing method is usually irregular in shape and its surface composition is not uniform. Although the shape and surface composition of the toner slightly change depending on the pulverization property of the material used for the production of the toner and the conditions of the pulverization process, it is difficult to intentionally control the shape and surface composition to a desired shape.
In addition, in a toner manufactured by a kneading and pulverizing method using a material having particularly high pulverization properties, various mechanical forces such as shearing force are applied to the toner in the developing machine, so that the toner is further pulverized. It often happens that the shape changes.
In this case, in the two-component developer, the pulverized toner adheres to the carrier surface, thereby promoting the deterioration of the charging characteristics of the developer. In the one-component developer, the pulverized toner Scatters or develops with a change in the shape of the toner, resulting in a problem of image quality degradation.

When the shape of the toner is indefinite, even if a fluidity aid is added to the toner, the fluidity decreases with time, so that sufficient fluidity cannot be obtained, and developability, transferability, and cleaning properties are not obtained. There is a problem that it gets worse. This is because the fine particles, which are fluidity aids, move to the recesses present on the toner particle surfaces and are embedded in the toner particles by mechanical force such as shearing force applied to the toner during image formation.
Further, when such toner is collected by a cleaning process, returned to the developing machine, and reused, there is a problem that image quality is likely to deteriorate. In order to prevent these problems, it is conceivable to increase the amount of the flow aid added to the toner. In this case, however, the problem is that black spots are generated on the photoreceptor and the flow aid particles are scattered. Will occur.

On the other hand, in a toner containing a release agent such as wax, the release agent may be exposed on the surface of the toner particles depending on the combination of the release agent and the binder resin component (thermoplastic resin). In particular, in the case of a toner obtained by combining a binder resin imparted with elasticity by a high molecular weight component and slightly pulverized, and a brittle wax such as polyethylene, a large amount of polyethylene is exposed on the surface of the toner particles.
Such a toner is advantageous for releasability at the time of fixing and cleaning of untransferred toner remaining on the surface of the photoreceptor. However, the release agent such as polyethylene present on the surface of the toner particles is easily transferred from the surface of the toner particles to a developing roll, a photoreceptor, a carrier, etc. by a mechanical force such as a shearing force applied to the toner in the developing machine. Cause pollution. Therefore, there is a problem that the developer using this toner lacks reliability.

Under such circumstances, a toner production method (so-called emulsion polymerization aggregation method) in which the shape and surface composition of the toner can be easily controlled has been proposed (see, for example, Patent Documents 1 and 2).
In the emulsion polymerization aggregation method, the particle size of the toner is adjusted in a mixed liquid obtained by mixing at least a resin fine particle dispersion prepared by emulsion polymerization or the like and a colorant dispersion obtained by dispersing a colorant in an aqueous medium (solvent). This is a method for producing a toner by forming the corresponding aggregated particles and then fusing the aggregated particles by heating.

In the case of the emulsion polymerization aggregation method, when preparing a resin fine particle dispersion or a colorant dispersion, an aggregation step in which the resin fine particles and the colorant particles are aggregated to form aggregated particles, and the aggregated particles are heated and fused. In the fusing step, a large amount of surfactant is used to stabilize the aggregated particles, and thus there is a problem that the surfactant remains in the finally obtained toner particles.
However, if the surfactant used in the agglomeration process or the fusion process is limited to a certain amount or less, the agglomeration property is reduced and unaggregated particles are generated, or the stability of the aggregated particles is insufficient in the fusion process. Deterioration of the particle size distribution and the like occur. Therefore, simply reducing the amount of the surfactant used causes a serious problem in the production of the toner.

  In addition, the toner obtained by the emulsion polymerization agglomeration method has an extremely excellent particle size distribution as compared with toner particles obtained by a polymerization method represented by a conventional suspension polymerization method, etc. There is an advantage that toner particles having an excellent irregular shape can be produced. However, in the toner obtained using this emulsion polymerization aggregation method, the remaining surfactant significantly reduces the toner's hygroscopic properties, which causes poor charging, high environmental dependency, and deterioration of storage stability. , Lack of reliability and durability.

In order to improve these problems, a metal salt containing a divalent or higher valent metal as an aggregating agent while minimizing the acid value of the toner and the amount of surfactant that may remain in the toner particles. There has been proposed a method of forming aggregated particles by using (see Patent Document 3).
The toner produced using this method has less charge remaining in the toner, and therefore has better charging characteristics than a toner produced using a large amount of a conventional surfactant. Environmental dependency is also improved dramatically.
Japanese Patent Laid-Open No. 63-282275 JP-A-6-250439 Japanese Patent Laid-Open No. 11-311877

However, in a toner prepared using a metal salt containing a metal having a valence of 2 or more as a flocculant, uneven glossiness of the image may occur or hot offset may deteriorate.
An object of the present invention is to solve the above problems. That is, an object of the present invention is to provide an electrostatic image developing toner capable of suppressing gloss unevenness and hot offset, an electrostatic image developing developer and an image forming method using the same.

In order to solve the above-mentioned problems, the present inventors have prepared unevenness of gloss when a metal salt containing a divalent or higher metal is used as an aggregating agent when a toner is produced using an emulsion polymerization aggregation method, The cause of the hot offset has been intensively studied.
First, when a metal salt is used as an aggregating agent in preparation of a toner by the emulsion polymerization aggregation method, these metal salts remain in the finally obtained toner. If the metal used as the aggregating agent is uniformly dispersed in the matrix material constituting the toner, it is considered that these metals form ionic crosslinks uniformly in the matrix material.

  On the other hand, if the metal is unevenly distributed in the matrix material without being uniformly dispersed or separated from the matrix material, it is considered that ionic crosslinks are not uniformly formed in the matrix material. In other words, unevenness occurs in the matrix material in terms of a bonding state called ionic crosslinking.

The inventors of the present invention formed an image using these toner particles because the unevenness of the viscoelasticity of each toner particle becomes uneven when such unevenness occurs particularly at the level between individual toner particles. In some cases, it was considered that gloss unevenness was caused.
In addition, when the ionic crosslinking in the matrix material is poor, the viscoelasticity is lowered. Therefore, the present inventors fix the toner image transferred onto a transfer medium such as paper, and when heated excessively, the viscosity of toner particles having relatively low viscoelasticity decreases. It was considered that a part of the toner image adheres to the fixing member side and so-called hot offset is likely to occur.
From the above, the present inventors need to suppress as much as possible the uneven distribution of the metal between the toner particles due to the coagulant that contributes to ionic crosslinking in the matrix material and affects the melting characteristics of the toner. The present invention was found as follows.

That is, the present invention
<1>
In an electrostatic charge image developing toner containing a binder resin, a colorant, and a metal having a valence of 2 or more,
The electrostatic charge image developing toner according to the invention, wherein the metal having a valence of 2 or more has a base material release rate of 18% or less and a metal element release rate of 15% or less.

<2>
The toner for developing an electrostatic charge image according to <1>, wherein the binder resin contains at least a polyester resin.

<3>
<2> The electrostatic image developing toner according to <2>, wherein the polyester resin is at least one selected from the group consisting of a crystalline polyester resin and an amorphous polyester resin.

<4>
In the raw material dispersion obtained by mixing at least a resin fine particle dispersion in which resin fine particles made of the binder resin are dispersed and a colorant dispersion in which colorant fine particles made of the colorant are dispersed, the resin fine particles and the colorant In the toner for developing an electrostatic charge image according to <1>, wherein the toner is produced by aggregating fine particles including fine particles to form aggregated particles.
In the electrostatic image developing toner, the aggregation step is performed by adding a metal salt containing a divalent or higher metal as an aggregating agent to the raw material dispersion.

<5>
<4> The electrostatic charge developing toner according to <4>, wherein a metal salt containing at least a trivalent or higher metal is used as the aggregating agent.

<6>
<4> The electrostatic charge developing toner according to <4>, wherein a metal salt containing at least polyaluminum chloride and a divalent or higher metal is used as the aggregating agent.

<7>
The electrostatic charge developing toner according to <4>, wherein the flocculant is added to the raw material dispersion over time.

<8>
The toner for developing an electrostatic charge image according to <1> containing a release agent,
The melting point of the release agent is in the range of 50 to 110 ° C., and the content of the release agent is in the range of 1 to 20 parts by weight with respect to 100 parts by weight of the binder resin. This is a toner for developing an electrostatic image.

<9>
In an electrostatic charge image developer including a toner containing a binder resin, a colorant, and a metal having a valence of 2 or more,
A developer for developing an electrostatic charge image, wherein the metal having a valence of 2 or more contained in the toner has a base material liberation rate of 18% or less and a metal element liberation rate of 15% or less. .

<10>
A latent image forming step for forming an electrostatic latent image on the surface of the latent image holding member, and development for forming the toner image by developing the electrostatic latent image formed on the surface of the latent image holding member with a developer containing toner. An image forming process including: a transfer process for transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target; and a fixing process for thermally fixing the toner image transferred on the surface of the transfer target. In the method
The image forming method, wherein the metal having a valence of 2 or more contained in the toner has a base material release rate of 18% or less and a metal element release rate of 15% or less.

  As described above, according to the present invention, there are provided an electrostatic image developing toner capable of suppressing gloss unevenness and hot offset, an electrostatic image developing developer and an image forming method using the same. be able to.

  Hereinafter, the present invention will be described in the order of a toner for developing an electrostatic image, a method for producing the same, an electrostatic image developer, and an image forming method.

<Electrostatic image developing toner and method for producing the same>
The electrostatic image developing toner of the present invention (hereinafter sometimes abbreviated as “toner”) is an electrostatic image developing toner containing a binder resin, a colorant, and a divalent or higher metal. A metal having a valence of 2 or more has a base material liberation rate of 18% or less and a metal element liberation rate of 15% or less.

When the base metal release rate and metal element release rate of a metal having a valence of 2 or more (hereinafter sometimes simply referred to as “metal”) satisfy the above ranges, uneven gloss and hot offset can be suppressed.
The base material liberation rate is preferably 16% or less, more preferably 14% or less, and the closer to 0%, the more preferable. The metal element liberation rate is preferably 12% or less, more preferably 10% or less, and the closer to 0%, the more preferable.
Further, when two or more kinds of metals are contained in the toner, it is necessary that the base material liberation rate is 18% or less and the metal element liberation rate is 15% or less for each metal.

  The toner of the present invention is preferably produced using a so-called emulsion polymerization aggregation method. In this case, the toner of the present invention is a raw material dispersion obtained by mixing at least a resin fine particle dispersion in which resin fine particles made of a binder resin are dispersed and a colorant dispersion in which colorant fine particles made of a colorant are dispersed. It is produced by at least an aggregating step of aggregating fine particles including resin fine particles and colorant fine particles to form aggregated particles. Here, the aggregating step is performed by adding a bivalent or higher-valent metal as an aggregating agent to the raw material dispersion. It is particularly preferred to carry out by adding a metal salt containing.

In the present invention, “a metal having two or more valences” that determines a base material liberation rate and a metal element liberation rate is, in a broad sense, a metal having a divalent or more valence (or a compound containing the metal). At that time, (1) the potential ability that can be dispersed in the matrix material constituting the toner, and (2) the potential ability that can form ionic crosslinks in the matrix material. means.
Specific examples of the metal having a valence of 2 or more (or a compound containing the metal) satisfying the above conditions (1) and (2) include a divalent used as an aggregating agent when a toner is produced by an emulsion polymerization aggregation method. The above metal salts are mentioned.

A metal salt having a valence of 2 or more has a potential ability to form an ionic bridge in a matrix material by ionic dissociation because a metal element forms an ionic bond with a pair of atoms.
In addition, since the metal salt having a valence of 2 or more is used in the aggregation process, it exists in a state of being mixed with fine particles such as resin fine particles and colorant fine particles constituting the aggregated particles. In particular, when the toner particles are formed into a main body portion or a core portion, the toner particles are incorporated into the aggregated particles, and thus have the potential to be dispersed in the matrix material.

  In addition, as a bivalent or higher metal (or a compound containing the same) satisfying the conditions of the above (1) and (2), the above bivalent or higher metal used when the present invention is produced by an emulsion polymerization aggregation method is used. It is not limited to the metal salt (coagulant | flocculant) containing these metals. For example, when the toner of the present invention is produced by a known toner production method other than the emulsion polymerization aggregation method, a metal having a valence of 2 or more contained in the toner satisfies the above conditions (1) and (2) If so, it does not have to be derived from a material having an auxiliary role that is not the raw material itself used as a flocculant in the emulsion polymerization aggregation method.

  On the other hand, when the toner is produced, a metal having a valence of 2 or more derived from a covalently bonded compound does not have the ability to form ionic crosslinks in the matrix material by ionic dissociation. Further, a bivalent or higher-valent metal (or a compound containing the same) externally added to the main part of toner particles (for example, aggregated particles prepared through an aggregation process) may be ion-dissociated. Since it does not have the ability to be dispersed in the matrix material, it does not fall under the above-mentioned “bivalent or higher metal” that determines the base material release rate and the metal element release rate.

Next, a method for obtaining the base material liberation rate and the metal element liberation rate of the metal element and the definition thereof will be described below.
A particle analyzer (manufactured by Horiba, Ltd., DP-1000) was used in order to obtain the metal element base metal release rate and metal element release rate. Using this device, the parameters necessary for determining the base metal release rate and metal element release rate (emission count of carbon atoms and metal elements) and other information (toner particle size, etc.) are measured as follows. did.

First, each toner particle to be measured collected in a membrane filter (polycarbonate) is sucked up by a special aspirator using He gas (helium gas containing 0.1% oxygen) as a carrier, and He micro It was introduced into a wave induction plasma (He-MIP: high temperature non-thermal equilibrium plasma having an electron density of 5 × 10 ¹³ cm ⁻³ , an excitation temperature of 3300 K, and a high electron temperature exceeding 20000 K). At this time, information on the elements constituting the particles, the number of particles, and the particle size of the particles can be obtained from the emission spectrum of the particles accompanying this excitation.

  Here, since the intensity of the emission spectrum is proportional to the number of atoms of the elements contained in the particles, the equivalent particle diameter (the particle size of each element contained in the particles is determined as a spherical simple substance using this). Assumed particle size) can be determined. That is, specifically, the equivalent particle diameter is obtained as a product of the third root of the intensity of the emission spectrum detected as a voltage (third root voltage) and a coefficient specific to each element. Further, since one light emission can be obtained from one particle, the number of particles can be obtained from the number of times of light emission.

  Further, when a plurality of elements are included in the particles, such as toner particles, the time when light emission due to one element is detected and the time when light emission due to another element is detected are simultaneous. The case is called “synchronous”, and the case where it is not simultaneous is called “asynchronous”. In the toner particles, by checking whether one element and the other element are “synchronous” or “asynchronous”, whether or not the external additive is attached to the main part of the toner particle, whether the internal additive is It is possible to determine whether the toner particles are loosely distributed in the toner particles or are uniformly dispersed.

Here, in the present invention, the base metal liberation rate and the metal element liberation rate of the metal element are obtained by paying attention to the emission spectrum of the carbon atom derived from the binder resin of the toner and the emission spectrum of the divalent metal element. Based on the emission spectrum intensity (emission count) in which the carbon element and the metal element are synchronous and the emission spectrum intensity (emission count) in which the carbon element and the metal element are asynchronous, the following expressions (1) and ( 2).
・ Formula (1)
Base material liberation rate = 100 × {C (NS) / [C (S) + C (NS)]}
・ Formula (2)
Metal element liberation rate = 100 × {M (NS) / [M (S) + M (NS)]}

However, in Formula (1) and Formula (2), C (S), C (NS), M (S), and M (NS) mean the light emission counts defined below, respectively.
C (S): Emission count of emission spectrum derived from a carbon atom detected synchronously with an emission spectrum derived from a metal element having a valence of 2 or more C (NS): Emission spectrum derived from a metal element having a valence of 2 or more The emission count of the emission spectrum derived from carbon atoms detected asynchronously M (S): The emission count of the emission spectrum derived from a metal element having two or more valences detected synchronously with respect to the emission spectrum derived from carbon atoms M (NS): Emission count of an emission spectrum derived from a metal element having two or more valences detected asynchronously with respect to an emission spectrum derived from a carbon atom

  Here, when the toner of the present invention is produced by an emulsion polymerization aggregation method, the emission count of the emission spectrum derived from a metal element having a valence of 2 or more; M (S) and M (NS) are used as an aggregating agent. It is a value determined by a metal having a valence of 2 or more.

In the measurement of the emission spectrum of a toner using a particle analyzer, the fact that carbon atoms and divalent or higher-valent metal elements emit light synchronously means that the divalent or higher-valent metal elements are taken into the toner binder resin. On the other hand, the fact that the carbon atom and the divalent or higher valent metal element do not emit light synchronously (that is, emit light asynchronously) means that the divalent or higher valent metal element is not taken into the binder resin. This is thought to suggest this.
Therefore, when asynchronous light emission is observed more intensely than synchronous light emission, a metal element having a bivalent or higher valence is not taken into the binder resin, or toner particles that are not sufficiently taken in Since the ratio is large and ionic crosslinking between the binder resin and the metal element derived from the flocculant cannot be performed, the viscoelastic behavior between the toner particles shifts in a non-uniform direction, and gloss unevenness and hot offset are likely to occur. It means that there is a tendency to become.
Therefore, the base material liberation rate defined by the above formula (1) needs to be 18% or less, and the metal element liberation rate defined by the above formula (2) needs to be 15% or less. is there.

  When the base material liberation rate exceeds 18% and / or the metal element liberation rate exceeds 15%, the viscoelastic behavior between the toner particles becomes non-uniform, resulting in uneven gloss and hot offset. End up. In addition, the increase in the metal element release rate has an adverse effect on the chargeability in addition to the occurrence of uneven gloss and hot offset, so the metal element release rate should be 15% or less in order to ensure good charging characteristics. Is preferred.

The divalent or higher metal contained in the toner of the present invention is not particularly limited as long as it is a known metal capable of taking a valence of 2 or higher. However, when using the emulsion polymerization aggregation method, Mg, Ca Ba, Zn, and Al are preferable.
In addition, when the divalent or higher valent metal contained in the toner of the present invention is derived from an aggregating agent (metal salt or metal complex) used when the toner is produced using the emulsion polymerization aggregation method, the divalent metal is divalent. At least one or more metal salts or metal complexes containing the above metals can be used, and at least one or more metal salts or metal complexes containing a trivalent or higher metal excellent in aggregation and granulation stability are preferably used. .
Examples of the metal salt that can be used as the flocculant include metal salts containing divalent or higher metals listed above; for example, metal salts containing divalent metal ions include calcium chloride, calcium nitrate, barium chloride, magnesium chloride, Magnesium sulfate, magnesium acetate, zinc chloride, zinc acetate, calcium polysulfide and the like can be mentioned, and examples of the metal salt containing a trivalent metal ion include aluminum nitrate, polyaluminum chloride and polyaluminum hydroxide.

Next, other characteristics, constituent materials, production methods and the like of the toner of the present invention will be described.
The component constituting the toner of the present invention is not particularly limited as long as it contains at least a binder resin, a colorant, and a divalent or higher metal as described above. In addition, other components such as a release agent may be included.

The toner of the present invention has a volume average particle diameter of preferably 1 to 20 μm, more preferably 2 to 8 μm, and a number average particle diameter of 1 to 20 μm is preferable and 2 to 8 μm is more preferable.
The volume average particle size and the number average particle size can be measured, for example, by using a Coulter counter [TA-II] type (manufactured by Coulter Inc.) and measuring with an aperture diameter of 50 μm. At this time, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (Isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

The melting point of the toner of the present invention is preferably in the range of 45 to 100 ° C., and more preferably in the range of 60 to 90 ° C.
Since the toner sharply decreases in viscosity at the melting point, the toner may cause blocking when stored in a temperature environment higher than the melting point. Therefore, it is preferable that the melting point of the toner is not less than a lower limit temperature in a general high-temperature environment that is exposed when the toner is stored or after an image is formed, that is, not less than 45 ° C. On the other hand, if the melting point exceeds 100 ° C., low-temperature fixing may not be possible.
This melting point can be determined as the melting peak temperature of the input compensated differential scanning calorimetry based on JIS K-7121. The crystalline resin may show a plurality of melting peaks, but the maximum peak is regarded as the melting point.

  Next, the constituent material of the toner of the present invention and the production method thereof will be described in detail below on the assumption that the toner is basically produced by an emulsion polymerization aggregation method. Of course, the constituent materials shown below can also be used when a toner is produced by a production method other than the emulsion polymerization aggregation method, and the toner production method of the present invention is not limited to the emulsion polymerization aggregation method. In addition, other wet manufacturing methods and dry manufacturing methods can be used.

-Binder resin-
The binder resin used in the toner of the present invention is not particularly limited as long as it is a known binder resin, and either a crystalline resin or an amorphous resin (amorphous resin) may be used. May be used.
The mixing ratio of crystalline resin and amorphous resin (amorphous resin) when both are used in combination depends on various properties such as low-temperature fixability, fogging, and image storage stability depending on the application and purpose. Can be selected as appropriate so as to balance the above. Moreover, when using both together, it is usually preferable that the ratio of the crystalline resin to the total binder resin is in the range of 20 to 60% by weight. Further, a toner having a so-called core-shell structure composed of a core layer containing a crystalline resin and a shell layer covering the core layer and containing an amorphous resin can also be produced.

  The “crystalline” of the crystalline resin that can be used in the toner of the present invention means that it has a clear endothermic peak, not a stepwise endothermic amount change in differential scanning calorimetry (DSC), Specifically, it means that the half-value width of the endothermic peak when measured at a heating rate of 10 (° C./min) is within 10 ° C. On the other hand, a resin having a half-value width exceeding 10 ° C. or a resin having no clear endothermic peak means an amorphous resin (amorphous resin), but as an amorphous resin used in the present invention, it is clear. It is preferable to use a resin having no endothermic peak.

The glass transition temperature and melting point of the binder resin used in the present invention are preferably 35 to 110 ° C., and 50 to 80 ° C. from the viewpoint of the balance between storage stability and toner fixing property. More preferred.
When the glass transition temperature is less than 35 ° C., blocking (a phenomenon in which toner particles aggregate and become agglomerates) tends to occur during storage or in a developing machine. On the other hand, if the glass transition temperature exceeds 100 ° C., the fixing temperature of the toner becomes high, which is not preferable.

The resin resin material is not particularly limited as long as it is a material that can be used as a binder resin for toner, and examples thereof include conventionally known thermoplastic binder resins.
Specifically, homopolymers or copolymers of styrenes such as styrene, parachlorostyrene, α-methylstyrene (styrene resin); methyl acrylate, ethyl acrylate, n-propyl acrylate, n-acrylate -Homopolymers or copolymers of esters having vinyl groups such as butyl, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc. Polymer (vinyl resin); homopolymer or copolymer of vinyl nitriles such as acrylonitrile and methacrylonitrile (vinyl resin); homopolymer or copolymer of vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether Coalescence (vinyl resin); vinyl methyl ketone, Homopolymers or copolymers of vinyl ketones such as nil ethyl ketone and vinyl isopropenyl ketone (vinyl resins); Homopolymers or copolymers of olefins such as ethylene, propylene, butadiene and isoprene (olefin resins) Non-vinyl condensation resins such as epoxy resins, polyurethane resins, polyamide resins, cellulose resins, and polyether resins, and graft polymers of these non-vinyl condensation resins and vinyl monomers. These resins may be used alone or in combination of two or more. Among these resins, vinyl resins are particularly preferable.

  The vinyl resin is advantageous in that the resin fine particle dispersion can be easily prepared by emulsion polymerization or seed polymerization using an ionic surfactant or the like. Examples of the vinyl monomer include acrylic acid, methacrylic acid, maleic acid, cinnamic acid, fumaric acid, vinyl sulfonic acid, ethylene imine, vinyl pyridine, vinyl amine, and other vinyl polymer acids and vinyl polymer bases. The monomer used as a raw material is mentioned.

  The concentration of the dissociating group in the dissociable vinyl monomer is determined by, for example, dissolving particles such as toner particles from the surface as described in Chemistry of Polymer Latex (Polymer Publication). Etc. can be determined. It should be noted that the molecular weight of the resin and the glass transition point from the surface of the particle to the inside can also be determined by the above method or the like.

As described above, various known resin materials can be used for the toner of the present invention. In the present invention, it is particularly preferable to use a polyester resin.
Hereinafter, the case where a polyester resin is used as the binder resin will be described in more detail. In this case, the polyester resin used in the present invention may be either crystalline or amorphous (amorphous) polyester resin, or a combination of both.

The acid value of the polyester resin used in the present invention is preferably 1.0 to 25.0 mgKOH / g, more preferably 6.0 to 20.0 mgKOH / g, and 9.0 to 18.0 mgKOH / g. More preferably, it is g.
When the acid value is less than 1 mg KOH / g, the balance with the valence of the metal salt used as the aggregating agent is lost, so the stability of the agglomerated particles formed in the agglomeration process becomes poor, and the particle size distribution of the toner May deteriorate, the toner yield may decrease, or coarse particles may be generated. On the other hand, when the acid value exceeds 25.0 mgKOH / g, the hygroscopicity of the toner increases, and the charge amount may be easily affected by the environment.
In addition, the acid value of the polyester resin can be adjusted by controlling the carboxyl group at the terminal of the polyester by the blending ratio and reaction rate of the raw material polycarboxylic acid and polyhydric alcohol. Or what has a carboxyl group in the principal chain of polyester is obtained by using trimellitic acid etc. as a polyvalent carboxylic acid component.
The acid value of the polyester resin is determined by neutralization titration with KOH. Specifically, methyl orange or the like is previously added as an indicator to a solution in which a resin is dissolved in a solvent, and a KOH titration amount is obtained by titrating the solution with a 1 mol KOH aqueous solution. Next, the acid value can be determined by dividing the KOH titration amount by the molecular weight 56 of KOH.

  Further, when the toner of the present invention is a toner having a so-called core-shell structure, the crystalline polyester resin forms a domain of the core layer, but it is preferable that this crystalline polyester phase is not exposed on the surface of the toner. Specifically, when the carbon atoms on the toner surface are analyzed by XPS (X-ray photoelectron spectroscopy), when the detection amount caused by all the carbon atoms on the toner surface is used as a reference (100%), the crystallinity of the toner surface. It is preferable that the detected amount of carbon atoms derived only from the polyester phase does not exceed 30%. When the exposure is large, the chargeability of the toner is remarkably lowered, so that the development characteristics may be deteriorated.

  The “crystalline polyester resin” used in the toner of the present invention is a polymer obtained by polymerizing a component constituting polyester and other components in addition to a polymer having a 100% polyester structure as a constituent component. (Copolymer) is also meant. However, in the latter case, it means that the component other than the polyester constituting the polymer (copolymer) is 50% by weight or less.

  The crystalline polyester resin that can be used in the present invention is mainly composed of a crystalline polyester resin synthesized using an aliphatic monomer (hereinafter sometimes abbreviated as “crystalline aliphatic polyester resin”) (50 % By weight or more). Furthermore, in this case, the constituent ratio of the aliphatic monomer constituting the crystalline aliphatic polyester resin is preferably 80 mol% or more, and more preferably 90 mol% or more. As aliphatic monomers, aliphatic diols and dicarboxylic acids as described later can be preferably used.

When the crystalline polyester resin is composed of aromatic or other non-aliphatic monomers, the melting point of the crystalline polyester resin is increased, resulting in an increase in the melting point of the finally produced toner and an increase in the fixing temperature of the toner. May invite. Further, since the emulsifiability of the resin necessary for producing the toner by the aggregation method is deteriorated, it may be difficult to control the particle size distribution at the time of toner granulation, or uneven distribution of the colorant may be caused.
On the other hand, when an aromatic sulfonic acid monomer is used as a constituent component in order to lower the melting point and impart emulsifying properties, even if the melting point can be lowered and the emulsifying property can be improved, the electrical resistance necessary for imparting toner chargeability can be reduced. As a result, the application range for satisfying the toner characteristics may be narrowed. Therefore, in order to enhance the improvement effect on the low-temperature fixability, the aliphatic monomer composition ratio is desirably 80 mol% or more.

  The amorphous polyester resin and crystalline polyester resin used in the toner of the present invention are synthesized from a polyvalent carboxylic acid component and a polyhydric alcohol component. In the present invention, a commercially available product may be used as the polyester resin, or an appropriately synthesized product may be used.

  Examples of the polyvalent carboxylic acid component include oxalic acid, succinic acid, glutaric acid, adipic acid, peric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12 -Aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconic acid Aromatic dicarboxylic acids such as dibasic acids such as, and the like, and anhydrides and lower alkyl esters thereof are also included, but not limited thereto.

  Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and the like, and anhydrides thereof. And lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.

  In addition, monocarboxylic acid and / or monoalcohol is further added to the polyester resin obtained by polycondensation of polycarboxylic acid and polyhydric alcohol to esterify the hydroxyl group and / or carboxyl group at the polymerization terminal. The acid value of the polyester resin may be adjusted. Examples of the monocarboxylic acid include acetic acid, acetic anhydride, benzoic acid, trichloroacetic acid, trifluoroacetic acid, propionic anhydride and the like, and examples of the monoalcohol include methanol, ethanol, propanol, octanol, 2-ethylhexanol, and trifluoroethanol. , Trichloroethanol, hexafluoroisopropanol, phenol and the like.

  Moreover, as an acid component, it is preferable that the dicarboxylic acid component which has a sulfonic acid group other than the above-mentioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid is contained. The dicarboxylic acid having a sulfonic acid group is effective in that it can favorably disperse a coloring material such as a pigment. Further, when the entire resin is emulsified or suspended in water to form fine particles, if a sulfonic acid group is present, it can be emulsified or suspended without using a surfactant as described later.

  Examples of the dicarboxylic acid having a sulfone group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. The divalent or higher carboxylic acid component having a sulfonic acid group is contained in an amount of 1 to 15 mol%, preferably 2 to 10 mol%, based on all carboxylic acid components constituting the polyester. When the content is low, the stability of the emulsified particles with time deteriorates. On the other hand, when the content exceeds 15 mol%, not only the crystallinity of the polyester resin is deteriorated but also the process of coalescing the particles after aggregation is adversely affected. There is a problem that it becomes difficult to adjust.

  Furthermore, in addition to the aforementioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid, a dicarboxylic acid component having a double bond may be contained. A dicarboxylic acid having a double bond can be suitably used to prevent hot offset at the time of fixing in that it can be radically cross-linked through the double bond. Examples of such dicarboxylic acids include, but are not limited to, maleic acid, fumaric acid, 3-hexenedioic acid, and 3-octenedioic acid. In addition, these lower esters, acid anhydrides and the like are also included. Among these, fumaric acid, maleic acid and the like are mentioned in terms of cost.

  Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin, and other aliphatic diols, cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A And aromatic diols such as bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct. One or more of these polyhydric alcohols can be used. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and among these, aromatic diols are more preferable. In order to secure good fixing properties, a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) may be used in combination with the diol in order to take a crosslinked structure or a branched structure.

  Among these, especially as a polyhydric alcohol component used for crystalline polyester resin, an aliphatic diol is preferable and a linear aliphatic diol having 7 to 20 carbon atoms in the main chain portion is more preferable. When the aliphatic diol is branched, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability may be deteriorated. Further, when the number of carbon atoms is less than 7, when the polycondensation with aromatic dicarboxylic acid is performed, the melting point becomes high and fixing at low temperature may be difficult. On the other hand, when the number exceeds 20, it is difficult to obtain practical materials. easy. The carbon number is more preferably 14 or less.

  Specific examples of the aliphatic diol suitably used for the synthesis of the crystalline polyester that can be used in the toner of the present invention include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1 , 5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1, Examples thereof include, but are not limited to, 12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol, and the like. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable in view of availability.

  The polyester resin can be produced by subjecting the polyhydric alcohol and polyhydric carboxylic acid to a condensation reaction according to a conventional method. For example, the above polyhydric alcohol and polyvalent carboxylic acid, if necessary, a catalyst, and blended in a reaction vessel equipped with a thermometer, a stirrer, a flow-down condenser, and in the presence of an inert gas (such as nitrogen gas), Heat at 150 to 250 ° C. to continuously remove by-product low-molecular compounds out of the reaction system, stop the reaction when a predetermined acid value is reached, cool, and obtain the desired reactant Can be manufactured.

  Examples of the catalyst used for the synthesis of this polyester resin include esterification catalysts such as organic metals such as dibutyltin dilaurate and dibutyltin oxide, and metal alkoxides such as tetrabutyl titanate. The amount of such a catalyst added is preferably 0.01 to 1% by weight based on the total amount of raw materials.

  On the other hand, in a toner having a so-called core-shell structure, when a crystalline polyester resin is used in combination as a core layer and an amorphous polymer is used as a shell layer, this amorphous polymer (amorphous resin) is tetrahydrofuran (THF). ) In the molecular weight measurement by gel permeation chromatography (GPC) method of soluble matter, the weight average molecular weight (Mw) is preferably 5,000 to 1,000,000, more preferably 7,000 to 500,000. Moreover, it is preferable that a number average molecular weight (Mn) is 2000-100000, it is preferable that molecular weight distribution Mw / Mn is 1.5-100, More preferably, it is 1.5-20.

When the weight average molecular weight and the number average molecular weight are smaller than the above ranges, while effective for low-temperature fixability, not only the hot offset resistance is remarkably deteriorated, but also the glass transition point of the toner is lowered. The storage stability such as toner blocking may be adversely affected.
On the other hand, if the molecular weight is larger than the above range, the hot offset resistance can be sufficiently provided, but the low-temperature fixability is deteriorated and the oozing of the crystalline polyester phase present in the toner is inhibited, so that the document storage stability is reduced. May be adversely affected. Therefore, it becomes easy to satisfy both the low-temperature fixability, the hot offset resistance, and the document storage stability by satisfying the above conditions.

  In the present invention, the molecular weight of the binder resin is measured by using a THF soluble material, measured with a THF solvent, using a Tosoh GPC / HLC-8120, a Tosoh column / TSKgel SuperHM-M (15 cm), and monodispersed. The molecular weight is calculated using a molecular weight calibration curve prepared with a polystyrene standard sample.

-Colorant-
The colorant used in the toner of the present invention is not particularly limited as long as it is a known colorant, and examples thereof include carbon black such as furnace black, channel black, acetylene black, and thermal black, bengara, bitumen, and titanium oxide. Inorganic pigments, fast yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine, para brown and other azo pigments, copper phthalocyanine, metal-free phthalocyanine and other phthalocyanine pigments, flavantron yellow, dibromoanthrone orange, perylene red, quinacridone red, Examples thereof include condensed polycyclic pigments such as dioxazine violet.

  Chrome Yellow, Hansa Yellow, Benzidine Yellow, Slen Yellow, Quinoline Yellow, Permanent Orange GTR, Pyrarozone Orange, Vulcan Orange, Watch Young Red, Permanent Red, Dupont Oil Red, Resol Red, Rhodamine B Lake, Lake Red C, Rose Bengal, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxalate, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment 57: 1, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Examples thereof include various pigments such as CI Pigment Blue 15: 3, and these can be used alone or in combination of two or more.

  In the toner of the present invention, the content of the colorant is preferably 1 to 30 parts by weight with respect to 100 parts by weight of the binder resin. Alternatively, a surface-treated colorant may be used if necessary. It is also effective to use a pigment dispersant. By appropriately selecting the type of the colorant, yellow toner, magenta toner, cyan toner, black toner and the like can be obtained.

-Release agent-
The release agent used as necessary for the toner of the present invention is not particularly limited as long as it is a known release agent. For example, natural waxes such as carnauba wax, rice wax, and candelilla wax, and low molecular weight polypropylene. , Low molecular weight polyethylene, sazol wax, microcrystalline wax, Fischer-Tropsch wax, paraffin wax, montan wax, etc. or mineral / petroleum wax, fatty acid ester, ester wax such as montanic acid ester, etc. It is not limited to. Moreover, these mold release agents may be used individually by 1 type, and may be used together 2 or more types.

  The melting point of the release agent is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, from the viewpoint of storage stability. Moreover, it is preferable that it is 110 degrees C or less from a viewpoint of offset resistance, and it is more preferable that it is 100 degrees C or less.

The content of the release agent is preferably in the range of 1 to 30 parts by weight and more preferably in the range of 2 to 20 parts by weight with respect to 100 parts by weight of the binder resin. When the content of the release agent is less than 1 part by weight, there is no effect of adding the release agent, and hot offset at a high temperature may be caused.
On the other hand, when the amount exceeds 30 parts by weight, the charging property is adversely affected, and the mechanical strength of the toner is reduced. Therefore, the toner is easily destroyed by stress in the developing machine, and may cause carrier contamination. Further, when used as a color toner, a domain having a large size made of a release agent tends to remain in a fixed image, and there is a problem that OHP transparency is deteriorated.

-Other additives-
In addition to the above-described components, various components such as an internal additive, a charge control agent, inorganic powder (inorganic fine particles), and organic fine particles can be added to the toner of the present invention as necessary. .
Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese, alloys, and magnetic materials such as compounds containing these metals.

Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments.
The inorganic powder is added mainly for the purpose of adjusting the viscoelasticity of the toner. For example, silica, alumina, titania, calcium carbonate, magnesium carbonate, calcium phosphate, cerium oxide, etc. Examples thereof include all inorganic fine particles used as an external additive on the toner surface.

Examples of inorganic fine particles and organic fine particles that are externally added to the toner surface include the following.
Examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride, Examples include Bengala, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, and silicon nitride. Among them, silica fine particles and titanium oxide fine particles are preferable, and hydrophobized fine particles are particularly preferable.

Inorganic fine particles are generally used for the purpose of improving fluidity. The primary particle diameter of the inorganic fine particles is preferably 1 to 200 nm, and the addition amount is preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the toner.
Organic fine particles are generally used for the purpose of improving cleaning properties and transfer properties, and specific examples include polystyrene, polymethyl methacrylate, polyvinylidene fluoride, and the like.

-Toner production method-
The method for producing the toner of the present invention is not particularly limited, but it is preferably produced by a wet granulation method. Examples of the wet granulation method include known melt suspension methods, emulsion polymerization aggregation methods, dissolution suspension methods, and the like. Among them, the emulsion polymerization aggregation method is preferably used in the present invention.
When the emulsion polymerization aggregation method is used, the method for producing the toner of the present invention is not particularly limited as long as it includes at least the aggregation step for forming the aggregated particles described above. However, usually, the agglomerated particles (including agglomerated particles obtained through the adhesion process described later) are fused by heating to obtain a fused particle, the agglomerated particles after the aggregating process, There may also be an attachment step for forming the agglomerated particles having the core-shell structure by attaching the amorphous polymer fine particles to the surface of the fusion particles after the fusion step. Hereinafter, each step will be described in detail.

-Emulsification process (adjustment of raw material dispersion)-
The raw material dispersion including the resin fine particle dispersion and the colorant dispersion used in the agglomeration step is composed of a binder resin emulsified particle (hereinafter abbreviated as “resin fine particles”), an aqueous medium, and a colorant, if necessary. It is formed by applying a shearing force to a solution obtained by mixing a dispersion containing a release agent. Therefore, the binder resin needs to be dispersed in advance as resin fine particles in the raw material dispersion.

The average particle size of the resin fine particles is usually 1 μm or less, preferably 0.01 to 1 μm.
If the average particle size of the resin fine particles exceeds 1 μm, the particle size distribution of the finally obtained toner may be broadened, or free particles may be generated, which may lead to a decrease in toner performance and reliability. On the other hand, when the average particle diameter is within the above range, there are no disadvantages as described above, and the uneven distribution among the toners is reduced, the dispersion in the toners is improved, and the variations in performance and reliability are reduced. The average particle size of the resin fine particles can be measured using, for example, a Coulter counter.

Examples of the dispersion medium used in various dispersions and raw material dispersions obtained by mixing these include aqueous media and organic solvents.
Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together.
In the present invention, it is preferable to add and mix a surfactant in an aqueous medium. Although it does not specifically limit as surfactant, For example, anionic surfactants, such as sulfate ester type, sulfonate type, phosphate ester type, soap type; amine salt type, quaternary ammonium salt type, etc. Nonionic surfactants such as polyethylene glycol-based, alkylphenol ethylene oxide adduct-based, polyhydric alcohol-based, and the like.
Among these, anionic surfactants and cationic surfactants are preferable. The nonionic surfactant is preferably used in combination with an anionic surfactant or a cationic surfactant. Surfactant may be used individually by 1 type and may use 2 or more types together.

Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate and the like. Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like. Among these, ionic surfactants such as anionic surfactants and cationic surfactants are preferable.
Examples of the organic solvent include ethyl acetate and toluene, which are appropriately selected according to the type of the binder resin.

  When the resin fine particles are homopolymers or copolymers (vinyl resins) of vinyl monomers such as vinyl group-containing esters, vinyl nitriles, vinyl ethers, vinyl ketones, etc. Disperse resin particles made of vinyl monomer homopolymer or copolymer (vinyl resin) in ionic surfactant by emulsion polymerization or seed polymerization in ionic surfactant A dispersion is prepared.

When the resin fine particle is a resin other than a homopolymer or copolymer of a vinyl monomer, if the resin is dissolved in an oily solvent having a relatively low solubility in water, the following is performed. The dispersion can be adjusted.
First, a solution obtained by dissolving this resin in an oily solvent is dispersed in water together with an ionic surfactant and a polymer electrolyte using a disperser such as a homogenizer. Next, the dispersion solution is prepared by dispersing resin fine particles made of resin other than vinyl resin in an ionic surfactant by heating or depressurizing the solution after dispersion to evaporate an oily solvent. it can.

On the other hand, when the resin fine particles are crystalline polyester and / or amorphous polyester resin, the polyester resin contains an anionic functional group that exhibits hydrophilicity by neutralization. A dispersion obtained by neutralizing a part or all of these functional groups with a base can be prepared.
In the crystalline polyester and the amorphous polyester resin, the functional group that can become a hydrophilic group by neutralization is an acidic group such as a carboxyl group or a sulfone group, and examples of the neutralizing agent include sodium hydroxide, potassium hydroxide, Examples thereof include inorganic bases such as lithium hydroxide, calcium hydroxide, sodium carbonate and ammonia, and organic bases such as diethylamine, triethylamine and isopropylamine.

Moreover, when using the polyester resin which does not disperse | distribute in water itself as binder resin, a dispersion liquid can be adjusted as follows similarly to the mold release agent mentioned later.
First, a solution in which a polymer electrolyte such as an ionic surfactant, a polymer acid, or a polymer base is added to a solution containing the resin and / or an aqueous medium mixed therewith is prepared. Next, when this solution is heated to a temperature equal to or higher than the melting point of the resin and processed using a homogenizer or a pressure discharge type disperser capable of applying a strong shearing force, a dispersion containing resin fine particles having a particle size of 1 μm or less can be easily obtained. Can be adjusted.
In addition, when using an ionic surfactant and a polymer electrolyte, it is preferable to adjust the density | concentration in the aqueous medium to about 0.5 to 5 weight%.

The colorant described above can be used as the colorant mixed with the resin fine particle dispersion.
As a method for dispersing the colorant, an arbitrary method, for example, a general dispersion method such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, or a dyno mill can be used, and there is no limitation. If necessary, an aqueous dispersion of these colorants can be prepared using a surfactant, or an organic solvent dispersion of these colorants can be prepared using a dispersant. As the surfactant and the dispersing agent used for dispersion, the same dispersing agents that can be used when dispersing the binder resin can be used.

The addition amount of the colorant is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, still more preferably 2 to 10% by weight based on the binder resin. It is particularly preferably 7% by weight, and it is preferably as much as possible as long as the smoothness of the image surface after fixing is not impaired. Increasing the amount of colorant added is advantageous in terms of preventing offset when the image having the same density can be obtained by reducing the thickness of the image.
In addition, these colorants may be added to the raw material dispersion together with other fine particle components, or may be divided and added in multiple stages.

As the release agent mixed with the resin fine particle dispersion, the release agent described above can be used.
Here, a dispersion containing a release agent (release agent dispersion) can be prepared as follows. First, similarly to the case of emulsifying and dispersing a polyester resin that does not have self-dispersibility in water, a solution in which a release agent is dispersed in water together with an ionic surfactant and the like is prepared. Next, this solution is heated to a temperature higher than the melting point of the release agent and a release agent having a particle size of 1 μm or less is dispersed by using a homogenizer or a pressure discharge type disperser capable of applying a strong shear force. The agent dispersion can be adjusted. As the dispersion medium in the release agent dispersion, the same dispersion medium as that for the binder resin can be used.

  In the present invention, for example, a homomixer (Special Machine Industries Co., Ltd.), a slasher (Mitsui Mine Co., Ltd.), Cavitron (stock) Eurotech Co., Ltd., Microfluidizer (Mizuho Industrial Co., Ltd.), Menton Gorin Homizer (Gorin Co., Ltd.), Nanomizer (Nanomizer Co., Ltd.), Static Mixer (Noritake Company), etc. .

The content of the resin fine particles contained in the resin fine particle dispersion and the content of each of the colorant and the release agent in the dispersion of the colorant and the release agent are usually 5 to 50% by weight, preferably 10 -40% by weight. If the content is outside the above range, the particle size distribution may be widened and the characteristics may be deteriorated.
Here, according to the purpose, other components such as the internal additive, the charge control agent, and the inorganic powder as described above may be dispersed in the resin fine particle dispersion. The charge control agent is preferably a material that is difficult to dissolve in water in terms of controlling ionic strength that affects the stability of the aggregation process and the fusion process and reducing wastewater contamination.

The volume average particle diameter of the other components described above is usually 1 μm or less, and preferably 0.01 to 1 μm. If the volume average particle size exceeds 1 μm, the particle size distribution of the finally obtained toner may be broadened, or free particles may be generated, leading to a decrease in toner performance and reliability.
On the other hand, when the volume average particle size is within the above range, the above disadvantages are eliminated, uneven distribution among the toners is reduced, dispersion in the toners is improved, and variations in toner performance and reliability are reduced. It is.

-Aggregation process-
In the aggregation step, a raw material dispersion obtained by mixing other dispersions such as a release agent dispersion added as necessary, in addition to the resin fine particle dispersion and the colorant dispersion, Heating is performed at a temperature slightly below the melting point of the binder resin (resin fine particles) to form aggregated particles in which the fine particles of each component are aggregated.

Aggregated particles are formed by adjusting a raw material dispersion obtained by further mixing a nonionic surfactant to various dispersions such as a resin fine particle dispersion and a colorant dispersion to an appropriate pH, and then adding the aggregating agent over time. It is preferable. This appropriate pH is a pH at which the flocculant works effectively, and differs slightly depending on the composition of the binder resin raw material dispersion. That is, when an amorphous polymer of a vinyl copolymer is used as the binder resin, the pH is preferably 3.5 to 6, and more preferably 4 to 6. On the other hand, when a polyester resin is used as the binder resin, the pH is preferably 2.5 to 4.0.
Further, “adding with time” means that the total amount of the flocculant is added to the raw material dispersion in at least two portions over a certain period of time. That is, in other words, it is preferable not to add the entire amount of the flocculant to the raw material dispersion at a time. If the total amount of the flocculant is added to the raw material dispersion at once, the flocculant will not be uniformly incorporated into the toner particles, resulting in non-uniform viscoelastic behavior between the toner particles, and uneven gloss and hot offset. It may be likely to occur. In addition, it may be difficult to control the particle size of the aggregated particles.

Note that the embodiment of the flocculant is not particularly limited as long as the flocculant is added to the raw material dispersion as described above, but in practice, the flocculant is added to ion-exchanged water or the like. The dissolved flocculant solution is preferably dropped into the raw material dispersion, and the dropping rate in this case is preferably 10 ml / min or less, more preferably 8 ml / min or less, and the dropping rate is small. Smaller is better. However, in order to prevent the time required for the aggregation step from becoming unnecessarily long, it is practically preferable that the dropping rate is 5 ml / min or more.
The addition of the flocculant over time, which is performed by dropping or the like, is desirably performed while moving the stirring means itself in the raw material dispersion so that the flocculant is evenly distributed over the raw material dispersion. For example, when the stirring means is a homogenizer, it can be stirred while moving it in the depth direction. Further, the stirring is more preferably performed with a stirring device having a large shearing force such as ultra turrax, and the aggregating agent is more uniformly dispersed when stirring at a high rotation speed of 5000 rpm or more for 5 minutes or more.

  Even when the nonionic surfactant is not added to the raw material dispersion, the coagulant may be unevenly distributed in the toner or the particle size of the aggregated particles may be difficult to control. Therefore, it is preferable to add a nonionic surfactant to the raw material dispersion used in the aggregation step.

As the aggregating agent used in the aggregating step, a metal salt or metal complex containing a divalent or higher metal as described above can be suitably used.
In order to obtain a sharper particle size distribution, the metal salt valence of the metal salt is trivalent than trivalent, tetravalent than trivalent, and even if the valence is the same. Is more suitable. Furthermore, in the present invention, it is particularly preferable to use polyaluminum chloride from the viewpoints of aggregation ability and suppression of variation in viscoelastic behavior between toner particles.

  In the agglomeration process, in order to suppress rapid aggregation due to heating of the raw material dispersion, the pH of the raw material dispersion is adjusted at the stage where the raw material dispersion maintained at about room temperature is stirred and mixed. Depending on the case, a dispersion stabilizer may be added to the raw material dispersion. (Hereinafter, this stage is referred to as “primary aggregation treatment”). The dispersion stabilizer can be effectively added separately during the primary aggregation treatment and during the heat treatment performed in the latter half of the aggregation process.

-Adhesion process-
At least after the aggregation step, an adhesion step can be performed as necessary. Here, in the adhering step, these particles (hereinafter referred to as the agglomerated particles and the fused particles used in the adhering step) are combined with the aggregated particles formed through the aggregating step and the fused particles formed through the aggregating step and the fusing step. Agglomerated particles in which a coating layer is formed by attaching resin fine particles such as amorphous polymer fine particles to the surface of both of them (sometimes referred to as “core particles”) (hereinafter sometimes referred to as “adhesive aggregated particles”) Form.

Since this coating layer corresponds to the surface layer (shell layer) of the toner formed through the fusing process, from the viewpoint of toner chargeability, the material for forming the coating layer is an amorphous high layer. It is preferable to use molecules.
The coating layer can be formed by additionally adding a resin fine particle dispersion containing amorphous polymer particles to the raw material dispersion in which the core particles are formed, and other components can be added simultaneously if necessary. It may be added.
Also in the adhesion step, the pH and the flocculant can be appropriately selected in the same manner as in the aggregation step depending on the amorphous polymer to be used. In addition, it is preferable to add the coagulant | flocculant in an adhesion process also with time like the aggregation process mentioned above.

  In addition, the heat treatment after the amorphous polymer fine particles are attached to the surface of the core particle is less than the melting point of the binder resin having the lowest melting point among the two or more kinds of binder resins contained in the attached aggregated particles. Performed at temperature. This adhesion step is also effective in aggregating again various fine particles that have not been incorporated into the core particles in the above-described aggregation step.

-Fusion process-
In the fusion step, the pH of the raw material dispersion containing the aggregated particles formed through the aggregation step or the adhered aggregated particles formed through the adhesion step under the same agitation as in the aggregation step is 6.5 to 9. After adjusting the range to 5 to stop the progress of aggregation, the aggregated particles or the adhered aggregated particles are fused by heating at a temperature equal to or higher than the melting point of the binder resin to obtain fused particles.
Depending on the liquidity of the raw material dispersion containing aggregated particles or adhered aggregated particles, if the pH at which aggregation is stopped is not within an appropriate range, the adhered aggregated particles or adhered aggregated particles may be heated during the fusion process. The toner yield may deteriorate.

There is no problem if the heating temperature at the time of fusion is not less than the melting point of the binder resin contained in the aggregated particles or the adhered aggregated particles. The heating time is preferably about 1 to 3 hours from the viewpoint of sufficient fusion and adjustment of the toner shape to a desired shape.
In the case of producing a toner having a core-shell structure in which the core layer is made of crystalline polyester, it is not preferable to perform the heat treatment longer than the above-described time. This is because the crystalline polyester contained in the core layer is likely to be exposed on the toner surface, which may adversely affect the chargeability.

Here, the end point of the fusing process is usually determined while monitoring the shape factor of the toner with FPIA-2100 (manufactured by SYSMEX).
A preferable shape factor measured by FPIA-2100 is 0.930 to 0.985. When the shape factor is less than 0.930, the toner surface has large irregularities, so that the external additives are unevenly distributed, and the convex portions formed on the toner surface wear due to mechanical stress, which causes an increase in toner fine powder. And may adversely affect the developability of the toner. On the other hand, when the shape factor is larger than 0.985, the toner shape approaches a spherical shape, which may cause deterioration in cleaning properties.

In the fusing step, a cross-linking reaction may be performed in which the material inside the toner particles is cross-linked during the heat treatment above the melting point of the binder resin or after the fusing step is completed.
For example, this crosslinking reaction uses an unsaturated sulfonated crystalline polyester resin obtained by copolymerizing a double bond component as a binder resin as a toner raw material, and causes a radical reaction in the resin during or after the fusion process. Can be implemented. At this time, the following polymerization initiator is used.

  Examples of the polymerization initiator include t-butyl peroxy-2-ethylhexanoate, cumyl perpivalate, t-butyl peroxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t. -Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxyca) Bonyl) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, , 3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylper) Oxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxy) (Cyclohexyl) propane, di-t-butylperoxy α-methylsuccinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexahydrotereph Tartrate, di-t-butylperoxyazelate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate), di-t-butylper Oxytrimethyl adipate, tris (t-butylperoxy) triazine, vinyltris (t-butylperoxy) silane, 2,2'-azobis (2-methylpropionamidine dihydrochloride), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine], 4,4′-azobis (4-cyanovaleric acid) and the like.

These polymerization initiators can be used alone or in combination of two or more. The amount and type of the polymerization initiator are selected depending on the amount of unsaturated sites in the resin capable of crosslinking reaction and the type and amount of the coexisting colorant.
The polymerization initiator may be mixed with the resin fine particles in advance when adjusting the resin fine particle dispersion, or may be incorporated into the aggregated particles formed in the aggregation step. Further, it may be introduced after the fusion step or after the fusion step.
When the polymerization initiator is introduced after the aggregation step, the adhesion step, the fusion step, or the fusion step, a solution in which the polymerization initiator is dissolved or emulsified is added to the resin fine particle dispersion or the raw material dispersion. These polymerization initiators may be added with known crosslinking agents, chain transfer agents, polymerization inhibitors and the like for the purpose of controlling the degree of polymerization.

After passing through the fusing step, the raw material dispersion containing the fusing particles is subjected to a solid-liquid separation step such as filtration, and a washing step, a drying step, and the like as necessary, whereby a toner can be obtained. In this case, in order to ensure sufficient charging characteristics and reliability as a toner, it is preferable to sufficiently wash in the washing step.
In the drying process, an arbitrary method such as a normal vibration type fluidized drying method, a spray drying method, a freeze drying method, or a flash jet method can be adopted. In the drying step, it is desirable to adjust the moisture content of the toner particles after the drying treatment to be preferably 1.0% or less, more preferably 0.5% or less.

  As described above, various known external additives such as inorganic fine particles and organic fine particles as described above can be added to the toner particles granulated through the drying step as described above according to the purpose.

<Developer for developing electrostatic image>
The electrostatic image developing toner of the present invention is used as it is as a one-component developer or as a two-component developer. When used as a two-component developer, it is used by mixing with a carrier.
There is no restriction | limiting in particular as a carrier which can be used for a two-component developer, A well-known carrier can be used. Examples thereof include magnetic metals such as iron oxide, nickel and cobalt, magnetic oxides such as ferrite and magnetite, resin-coated carriers having a resin coating layer on the surface of the core material, and magnetic dispersion carriers. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples thereof include, but are not limited to, acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins and the like.

  Examples of the conductive material include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black. It is not limited.

  Examples of the core material of the carrier include magnetic metals such as iron, nickel and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, it is a magnetic material. It is preferable. The volume average particle size of the core material of the carrier is generally 10 to 500 μm, preferably 30 to 100 μm.

  In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be appropriately selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in a coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the surface of the carrier core material, and the carrier core material is fluidized air. And a kneader coater method in which the core material of the carrier and the coating layer forming solution are mixed in a kneader coater and the solvent is removed in a kneader coater.

  The mixing ratio (weight ratio) of the toner of the present invention and the carrier in the two-component developer is in the range of toner: carrier = 1: 100 to 30: 100, and about 3: 100 to 20: 100. A range is more preferred.

<Image forming method>
The image forming method of the present invention includes a latent image forming step of forming an electrostatic latent image on the surface of the latent image holding member, and developing the electrostatic latent image formed on the surface of the latent image holding member with a developer containing toner. A developing step for forming a toner image, a transfer step for transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target, and a heat fixing of the toner image transferred to the surface of the transfer target. The toner of the present invention is used as the toner.

  The developer may be either a one-component system or a two-component system. As each of the above steps, a known step in the image forming method can be used. The image forming method of the present invention may include steps other than the steps described above.

As the latent image holding member, for example, an electrophotographic photosensitive member and a dielectric recording member can be used.
In the case of an electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger or the like and then exposed to form an electrostatic latent image (latent image forming step). Next, the toner particles are attached to the electrostatic latent image by contacting or approaching a developing roll having a developer layer formed on the surface, thereby forming a toner image on the electrophotographic photosensitive member (developing step). The formed toner image is transferred onto the surface of a transfer medium such as paper using a corotron charger or the like (transfer process). Further, the toner image transferred to the surface of the transfer target is heat-fixed by a fixing device to form an image.

  In the heat fixing by the fixing machine, in order to prevent an offset or the like, a release agent is usually supplied to a fixing member of the fixing machine by a release agent supplying means. When used, it is not necessary to supply a release agent to the fixing member (so-called oilless fixing).

  Further, when the toner of the present invention used for image formation has a cross-linked structure in the binder resin, it is excellent in releasability, so that the amount of the release agent supplied to the fixing member is reduced, or Fixing can be performed without using a release agent.

The release agent supplied by the release agent supply means is preferably not used from the viewpoint of eliminating the adhesion of oil to the transfer target and image after fixing. However, when the supply amount of the release agent is set to 0 mg / cm ² , the amount of wear of the fixing member increases when the fixing member and the transfer medium such as paper come into contact during fixing, and the durability of the fixing member decreases. May end up. Therefore, if necessary, it is preferable that a small amount of the release agent is supplied to the fixing member in a range of 8.0 × 10 ⁻³ mg / cm ² or less.

When the supply amount of the release agent exceeds 8.0 × 10 ⁻³ mg / cm ² , the image quality deteriorates due to the release agent adhering to the image surface after fixing, and in particular, transmitted light such as OHP is used. In such a case, such a phenomenon may appear remarkably. Further, the adhesion of the release agent to the transfer target becomes remarkable, and stickiness may occur. Further, the larger the supply amount of the release agent, the larger the capacity of the tank for storing the release agent, which causes an increase in the size of the fixing device itself.

The release agent supplied to the fixing member is not particularly limited, and examples thereof include liquid release agents such as modified oils such as dimethyl silicone oil, fluorine oil, fluorosilicone oil, and amino-modified silicone oil. Among them, a modified oil such as an amino-modified silicone oil is preferable because it can be adsorbed on the surface of the fixing member to form a homogeneous release agent layer and has excellent paintability to the fixing member. Further, from the viewpoint of forming a homogeneous release agent layer, fluorine oil and fluorosilicone oil are preferable.
When fluorine oil or fluorosilicone oil is used as the release agent, the supply amount of the release agent can be drastically reduced as compared with the case of using other release agents, which is advantageous in terms of cost.

There is no particular limitation on the method for supplying a release agent to the surface of a fixing member such as a roller or belt used for thermocompression bonding, for example, a pad method using a pad impregnated with a liquid release agent, or a web method. , Roller system, non-contact shower system (spray system), etc., among which web system and roller system are preferable.
These methods are advantageous in that the release agent can be supplied uniformly and the supply amount can be easily controlled. In order to supply the release agent uniformly to the entire fixing member by the shower method, it is necessary to use a separate blade or the like.

The supply amount of the release agent can be measured as follows. That is, when a normal paper (typically a copy paper manufactured by Fuji Xerox Co., Ltd., trade name J paper) used in a general copying machine is passed through a fixing member supplied with a release agent on its surface. The release agent adheres to the plain paper. The attached release agent is extracted using a Soxhlet extractor. Here, hexane is used as the solvent.
By quantifying the amount of the release agent contained in the hexane with an atomic absorption analyzer, the amount of the release agent adhering to the plain paper can be quantified. This amount is defined as the amount of release agent supplied to the fixing member.

Examples of the transfer target (recording material) to which the toner image is transferred include plain paper, OHP sheet, and the like used in electrophotographic copying machines and printers.
In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer target is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with resin, art paper for printing, etc. Can be preferably used.

  Since the image forming method of the present invention described above uses the developer of the present invention (the toner of the present invention), the occurrence of uneven glossiness of the image and the occurrence of hot offset can be suppressed.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the following description, “part” means “part by weight”.
-Preparation of amorphous polyester resin dispersion (1)-
Bisphenol A ethylene oxide adduct (average number of moles added 2.2): 221.2 parts Trimethylolpropane: 40.2 parts Terephthalic acid: 157.7 parts Trimellitic acid: 9.6 parts Stirrer, The raw materials listed above were charged into a 5 liter flask equipped with a nitrogen inlet tube, temperature sensor, and rectifying column, and after reducing the air in the flask by depressurization, the atmosphere was further replaced with nitrogen gas. The temperature was heated to 190 ° C. over 1 hour.

After confirming that the inside of the flask was uniformly stirred, 1.2 parts of dibutyltin oxide was put into the flask, and again in a nitrogen atmosphere. And heated to 240 ° C. over 6 hours.
Next, the flask was distilled under reduced pressure for 3 hours while maintaining the temperature at 240 ° C., and the dehydration condensation reaction was continued to obtain an amorphous polyester resin (1) having an acid value of 16.9 mgKOH / g and a weight average molecular weight of 21,400. It was.

Subsequently, this resin was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. In addition, dilute ammonia water (concentration: 0.37% by weight) obtained by diluting ammonia water with ion-exchanged water is put into a separately prepared tank and heated at 120 ° C. with a heat exchanger at a rate of 0.1 liter per minute. The polyester resin melt was transferred to the Cavitron (manufactured by Eurotech Co., Ltd.).
Next, the Cavitron was operated with the rotational speed of the rotor set to 60 Hz and the pressure set to 5 Kg / cm ² , and the amorphous polyester dispersion liquid (1) (resin fine particles containing polyester resin fine particles having a volume average particle size of 0.18 μm. Concentration: 20% by weight).

-Preparation of amorphous polyester resin dispersion (2)-
・ Ethylene glycol: 486 parts ・ Neopentyl glycol: 650 parts ・ Terephthalic acid: 957 parts The reaction was carried out under substantially the same conditions as those for preparing the amorphous polyester resin (1) except that the above raw materials were charged into the flask. The resin having an acid value of 5.8 mgKOH / g and a softening point of 105 ° C. was obtained by appropriately adjusting the dehydration condensation reaction time and the temperature during the dehydration condensation.
Next, after the temperature of the raw material dispersion containing this resin was lowered to 190 ° C., 497 parts of phthalic anhydride was gradually added to the flask, and the reaction was continued at 190 ° C. for 1 hour, whereby the acid value was 49 mgKOH / An amorphous polyester resin (2) having a weight average molecular weight of 33,000 in g was obtained.
Finally, this resin is emulsified and dispersed with Cavitron in the same manner as in the preparation of the amorphous polyester resin dispersion (1), and the amorphous polyester resin dispersion (2) containing polyester resin fine particles having a volume average particle size of 0.22 μm. (Resin fine particle concentration: 25% by weight) was obtained.

-Preparation of amorphous styrene-acrylic resin dispersion (1)-
-Styrene: 407 parts-n-butyl acrylate: 33 parts-Acrylic acid: 4.4 parts-Dodecanethiol: 26.4 parts-Carbon tetrabromide: 4.4 parts A solution prepared by mixing and dissolving the above raw materials was prepared. . Next, this solution was ion-exchanged with 6 parts of a nonionic surfactant (Sanyo Kasei Co., Ltd .: Nonipol 400) and 11 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC). In addition to the solution dissolved in 620 parts of water, 55 parts of ion-exchanged water having 4.4 parts of ammonium persulfate dissolved therein was added thereto while being dispersed and emulsified in a flask and slowly mixed for 10 minutes.

Then, after carrying out nitrogen substitution in the flask, the contents in the flask were heated with an oil bath until the content reached 70 ° C. while stirring, and emulsion polymerization was continued for 5 hours.
Thus, an amorphous styrene-acrylic resin dispersion (1) in which resin fine particles having a volume average particle size of 0.18 μm, a glass transition point of 56 ° C., and a weight average molecular weight of 15800 are dispersed (resin fine particle concentration: 40% by weight). )

-Preparation of crystalline polyester resin dispersion (1)-
・ 1,10 dodecanedioic acid: 182.8 parts ・ Dimethyl-5-sulfonic acid sodium salt: 5.9 parts ・ 5-t-butylisophthalic acid: 16.7 parts ・ 1,9 nonanediol: 160 parts Heating The above raw material was put into a three-necked flask equipped with a stirrer, a nitrogen introducing tube, a temperature sensor, and a rectifying tower, and Ti (OBu) ₄ (0 to 5-t-butylisophthalic acid as a catalyst). .014 wt%), the air in the flask was depressurized by depressurization, and the atmosphere was made inert with nitrogen gas, followed by refluxing at 180 ° C. for 6 hours with mechanical stirring.

Thereafter, methanol distilled into the flask was removed by distillation under reduced pressure, the temperature was gradually raised to 220 ° C., and the mixture was stirred for about 4 hours. Here, when the solution in the flask became viscous, the molecular weight of the resin formed in the solution was confirmed by GPC. When the weight average molecular weight reached 27000, the vacuum distillation was stopped, Was cooled with air to obtain a crystalline polyester resin (1).
Subsequently, this was emulsified and dispersed with a Cavitron under the same conditions as for preparation of the amorphous polyester resin dispersion (1), and a crystalline polyester resin dispersion (2) containing resin fine particles having a volume average particle size of 0.23 μm (resin fine particles Concentration: 20% by weight).

-Preparation of crystalline polyester resin dispersion (2)-
・ Dimethyl-5-sulfonate sodium phthalate: 5.9 parts ・ 5-t-butylisophthalic acid: 11.1 parts ・ 1,9-nonanediol: 160 parts Heat drying to stirrer, nitrogen inlet tube, temperature In a three-necked flask equipped with a sensor and a rectifying column, the above raw materials were added, and further, Ti (OBu) ₄ (0.016 wt% with respect to 5-t-butylisophthalic acid) was added as a catalyst. The air in the flask was decompressed by depressurization, and further brought into an inert atmosphere with nitrogen gas, and then the solution in the flask was stirred at 180 ° C. until the solution became transparent.

When the solution became transparent, 154.4 parts of terephthalic acid was further added to this solution, the air in the flask was again decompressed by depressurization, and the atmosphere was made inert with nitrogen gas at 180 ° C. with mechanical stirring. Refluxed for 7 hours.
Thereafter, the inside of the flask was distilled under reduced pressure to remove the distillate, and the solution was further stirred for about 6 hours while gradually raising the temperature to 240 ° C. At this time, when the solution became viscous, the molecular weight of the resin formed in the solution was confirmed by GPC. When the weight average molecular weight of the resin reached 26000, the vacuum distillation was stopped, -Soluble polyester resin (2) was obtained.
Next, this resin is emulsified and dispersed with Cavitron under the same conditions as for preparation of the amorphous polyester resin dispersion (1), and a crystalline polyester resin dispersion (2) containing resin fine particles having a volume average particle size of 0.19 μm (resin fine particles Concentration: 20% by weight).

-Preparation of release agent dispersion-
・ Paraffin wax (Nippon Seiwa Co., Ltd .: HNP9, melting point 77 ° C.): 50 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 5 parts ・ Ion-exchanged water: 200 parts or more The solution in which the above components were mixed was heated to 110 ° C., and then dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and further dispersed by a Manton Gorin high-pressure homogenizer (Go-Rin). By this treatment, a release agent dispersion liquid (release agent concentration: 20% by weight) in which a release agent having a volume average particle diameter of 210 nm was dispersed was obtained.

-Preparation of colorant dispersion-
-Cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3 (copper phthalocyanine)): 100 parts-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R): 15 parts-Ion-exchanged water: 900 Part of the above mixed and dissolved solution is dispersed for about 1 hour using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006) to disperse a colorant (cyan pigment). A liquid was prepared. The volume average particle size of the colorant (cyan pigment) contained in this colorant dispersion was 0.14 μm, and the colorant particle concentration was 28% by weight.

Example 1
-Production of toner base particles (1)-
Amorphous polyester resin dispersion (1): 350 parts Colorant dispersion: 17.85 parts Release agent dispersion: 50 parts The above raw materials are placed in a 5 L cylindrical stainless steel container, heated to 60 ° C and Ultraturrax. While adding a shearing force at 6000 rpm, 2.0 parts of a nonionic surfactant (IGEPAL CA80097) was added and dispersed and mixed for 5 minutes.

Next, this raw material dispersion was once cooled to 40 ° C., and the pH was adjusted to 2.7 with a 0.3N nitric acid aqueous solution while stirring at 3000 rpm with Ultraturrax. Next, a flocculant solution obtained by diluting 2.62 parts of calcium chloride as a flocculant with 15 parts of ion-exchanged water as a flocculant was slowly dropped into the raw material dispersion after pH adjustment at a dropping speed of about 10 ml / min.
At this time, since the raw material dispersion to which the flocculant solution is added thickens and various raw materials and the flocculant may be mixed unevenly, Ultraturrax is sufficient while moving the stainless steel container up and down, left and right Stir and mix. At this time, aggregated particles having a volume average particle diameter of 2.7 μm were formed in the raw material dispersion.

  The raw material dispersion prepared in this way is set in a polymerization kettle equipped with a stirrer, a pH meter, and a thermometer, and stirred at a stirring speed of 400 rpm, with a mantle heater up to 60 ° C. at a heating rate of 10 ° C./min. The temperature was raised. When the temperature reached 60 ° C., the stirring speed was reduced to 350 rpm in order to further grow the aggregated particles, and the growth of the aggregated particles was observed with an optical microscope.

  When the volume average particle diameter of the aggregated particles becomes 4.0 μm, 75 parts of the amorphous polyester resin dispersion (1) is added to the raw material dispersion to add amorphous polyester resin fine particles to the aggregated particles. Adhesive aggregated particles were formed by deposition and grown. When the desired particle size was approached, the pH of the raw material dispersion was raised to 8.7 with a 0.1N aqueous sodium hydroxide solution in order to stop particle growth of the adhered and agglomerated particles. Subsequently, in order to fuse the adhered aggregated particles and prevent the adhered aggregated particles from being dispersed, the stirring speed of the raw material dispersion after pH adjustment was lowered to 200 rpm, and then the temperature was raised to 75 ° C.

In this fusion process, the shape factor of the particles fused with FPIA-2100 was monitored while confirming the state in which the adhered and agglomerated particles were fused with an optical microscope and the shape of the particles. Here, when the shape factor of the fused particles reached 0.976, ice water was poured into the raw material dispersion and rapidly cooled at a cooling rate of 100 ° C./min. Thereafter, in order to wash the surface of the fused particles with alkali, a 1N aqueous sodium hydroxide solution was added to raise the pH of the raw material dispersion to 9.5.
Subsequently, this raw material dispersion was once filtered, and the fused particles obtained by solid-liquid molecules were dispersed and washed with deionized water three times. Further, the fused particles were washed by adjusting the slurry containing the fused particles after washing to pH 4.2 and a temperature of 40 ° C. with a 0.3N nitric acid aqueous solution. Finally, the fused particles were washed with deionized hot water (40 ° C.) and further dried to obtain toner base particles (1) having a volume average particle size of 6.4 μm.

(Example 2)
-Production of toner base particles (2)-
In Example 1, granulation was performed in the same manner as in the toner mother particles (1) except that 1.36 parts of aluminum sulfate was used as the flocculant instead of calcium chloride. Under the same conditions as in Example 1, Washing and drying were performed to obtain toner base particles (2) having a volume average particle size of 6.8 μm.

(Example 3)
-Production of toner base particles (3)-
In Example 1, the toner base was used except that a solution obtained by diluting 1.09 parts of calcium chloride and 0.94 parts of an aqueous nitric acid solution containing 10% by weight of polyaluminum chloride with 15 parts of ion-exchanged water was used as the flocculant solution. Granulation was performed in the same manner as the particles (1). Further, washing and drying were performed under the same conditions as in Example 1 to obtain toner mother particles (3) having a volume average particle size of 6.3 μm.

Example 4
-Production of toner base particles (4)-
Amorphous polyester resin dispersion (1): 175 parts Crystalline polyester resin dispersion (1): 175 parts Colorant dispersion: 17.85 parts Release agent dispersion: 50 parts Nonionic surface activity Agent (IGEPAL CA897): 2.0 parts Using the above dispersions as raw materials, as a flocculant solution, 1.16 parts of nitric acid aqueous solution containing 1.09 parts of calcium chloride and 10% by weight of polyaluminum chloride as ion-exchanged water Granulation was carried out in the same manner as toner mother particles (1) except that the liquid diluted with 15 parts was used.
Subsequently, washing and drying were performed under the same conditions as in Example 1 to obtain toner mother particles (4) having a volume average particle diameter of 6.9 μm.

(Example 5)
-Production of toner base particles (5)-
In Example 4, granulation was performed in the same manner as the toner base particles (4) except that the release agent dispersion was not used when adjusting the raw material dispersion in the aggregation step.
Further, washing and drying were performed under the same conditions as in Example 1 to obtain toner mother particles (5) having a volume average particle diameter of 6.5 μm.

(Example 6)
-Production of toner base particles (6)-
Amorphous polyester resin dispersion (2): 200 parts Crystalline polyester resin dispersion (2): 175 parts Colorant dispersion: 17.85 parts Release agent dispersion: 50 parts Nonionic surface activity Agent (IGEPAL CA897): 2.0 parts Each of the above dispersions is used as a raw material, and a liquid obtained by diluting 1.36 parts of an aqueous nitric acid solution containing 10% by weight of polyaluminum chloride with 20 parts of ion-exchanged water as a coagulant solution is used. In the adhering step, granulation was performed under the same conditions as in Example 1 except that 50 parts of the amorphous polyester resin dispersion (2) was used instead of the amorphous polyester resin dispersion (1). It was.
Subsequently, washing and drying were performed under the same conditions as in Example 1 to obtain toner base particles (6) having a volume average particle size of 6.6 μm.

(Comparative Example 1)
-Production of toner base particles (7)-
In Example (1), granulation was performed under the same conditions as in Example (1) except that 3.86 parts of sodium chloride was used instead of calcium chloride as the flocculant. Further, washing and drying were performed under the same conditions as in Example 1 to obtain toner mother particles (7) having a volume average particle size of 5.6 μm.

(Comparative Example 2)
-Production of toner base particles (8)-
In Example (1), each raw material was placed in a 5 L cylindrical stainless steel container, and then stirred with a stirring blade at room temperature without adding a nonionic surfactant (IGEPAL CA80097). The subsequent steps were granulated under the same conditions as in Example (1) except that the pH was adjusted to 4.5 with an aqueous solution. Further, washing and drying were performed under the same conditions as in Example 1 to obtain toner mother particles (8) having a volume average particle diameter of 6.4 μm.

(Comparative Example 3)
-Production of toner base particles (9)-
In Example (1), each raw material was placed in a 5 L cylindrical stainless steel container, and then stirred with a stirring blade at room temperature without adding a nonionic surfactant (IGEPAL CA8009). Granulation was performed under the same conditions as in Example (1) except that the pH was adjusted to 4.0 with an aqueous solution and the flocculant aqueous solution was further added at once. Further, washing and drying were performed under the same conditions as in Example 1 to obtain toner mother particles (9) having a volume average particle diameter of 6.7 μm.

(Comparative Example 4)
-Production of toner base particles (10)-
In Example 4, when adding the flocculant solution to the raw material dispersion while stirring the raw material dispersion with a homogenizer in the flocculation step, the flocculant solution was not added dropwise, but once, The raw material dispersion after being added to the toner was granulated in the same manner as the toner base particles (4) except that the homogenization was stopped by lightly stirring.
Further, washing and drying were performed under the same conditions as in Example 1 to obtain toner mother particles (10) having a volume average particle diameter of 7.1 μm.

<Various toner evaluation>
(Measurement of light emission count by particle analyzer)
The measurement of the light emission count with a particle analyzer (manufactured by Horiba, Ltd .: DP-1000) was performed by the measurement method described above under the following conditions.
In the measurement of the luminescence count, carbon atoms were measured in channel 2, and divalent or higher metals were measured in channels after channel 3. Here, sampling is performed so that the number of light emission of carbon atoms is 500 to 1000 in one scan, and the scan is repeated until the total number of light emission of carbon atoms reaches 10,000 or more, and the light emission number is integrated to emit light. Counts were measured.

  At this time, in the particle size distribution curve of the graph in which the vertical axis represents the number of light emission of a metal having a valence of 2 or more and the cube root voltage representing the equivalent particle diameter represents the horizontal axis, if the maximum value of this curve is 1, It suggests that the viscoelastic behavior between the toner particles is uniform, and if the maximum value is two, it indicates that the viscoelastic behavior between the toner particles tends to be non-uniform. In addition, the emission count number of the asynchronous metal element was obtained by counting the emission number of only the metal element when the scan was stopped when the total number of emission of carbon atoms reached 10,000 or more. At this time, the noise cut level was set to 1.0V.

  Various characteristics of the toner base particles prepared as described above, and fixing characteristics, document storability, charging characteristics, gloss unevenness, image quality (excluding gloss unevenness) of the toner for developing an electrostatic image prepared using the toner base particles The evaluation results are shown in Table 1. Note that “G1” to “G5” in Table 1 indicate the above-described document preservation grades.

  In addition, the evaluation method and evaluation criteria of each evaluation item shown in Table 1 are as follows.

(Evaluation of fixability and document preservation)
The toner base particles (1) to (10) are each added with 1.2 parts by weight of titania fine powder as an external additive with respect to 100 parts by weight of the toner and mixed with a Henschel mixer to add the externally added toners (1) to (10). )
Subsequently, 5 parts by weight of each of these externally added toners and 100 parts by weight of resin-coated ferrite particles (average particle size 35 μm) were mixed to prepare a two-component developer, which was then mixed with a commercially available electrophotographic copying machine (Fuji Xerox). A-color 635) was used to obtain an image, and a sample on which an unfixed image was formed was obtained.

Next, using a belt nip type external fixing device, the fixing temperature of the image and the hot offset property were evaluated while gradually increasing the fixing temperature between 110 ° C. and 220 ° C.
The low-temperature fixability is determined by fixing an unfixed solid image (25 mm × 25 mm), bending it with a weight under a certain load, grading the degree of image defect in that portion, and fixing temperature at which it exceeds a certain grade. Was used as an index of low-temperature fixability.

On the other hand, regarding the evaluation of document storage stability, after fixing two unfixed image samples prepared for the above fixability evaluation at 150 ° C. with an external fixing machine, an image portion, a non-image portion, and an image portion Folded facing each other so as to overlap each other, a weight was placed on the overlapped portion so as to be equivalent to 80 g / cm ^2, and left in a constant temperature and humidity chamber at 60 ° C. and 50% humidity for 7 days. After leaving, as shown in Table 1, the degree of image loss of the two superimposed fixed images was graded in the following five stages “G1” to “G5”.

G1: Since the image portions are adhered to each other, the paper on which the image is fixed is peeled off, image loss is severe, and clear image transfer to the non-image portion is observed.
G2: Since the images are bonded to each other, white spots of image defects are generated in some parts of the image portion.
G3: When separating two superimposed images, image blurring or gloss reduction occurs on the fixing surfaces of each other, but the image has an acceptable level with almost no image loss. Some transition is seen in the non-image area.
G4: When the two overlapped images are separated, a crisp sound is heard, and a slight image transition is seen in the non-image part, but there is no image loss and there is no problem at all. G5: Both the image part and the non-image There is no image loss or image transfer.

(Evaluation of chargeability)
Weighing 1.5 parts by weight of each of the externally added toners (1) to (10) and 30 parts by weight of resin-coated ferrite particles (volume average particle diameter 35 μm) prepared in the evaluation of the fixability in a glass bottle with a lid After seasoning for 24 hours under high temperature and high humidity (temperature of 28 ° C., humidity of 85%) and low temperature and low humidity (temperature of 10 ° C., humidity of 15%), the mixture was shaken with a turbula mixer for 5 minutes. The charge amount (μc) of the toner in both environments was measured with a blow-off charge amount measuring device.

(Evaluation of image quality)
36 parts by weight of each of the externally added toners (1) to (10) prepared for evaluation of the fixing property and 450 parts by weight of ferrite particles (volume average particle diameter 35 μm) coated with a resin were deblended with a V-type blender and developed. After preparing agents (1) to (10), a copy test was performed using a modified A-Color 635 machine manufactured by Fuji Xerox Co., Ltd.
In this modified machine, the transfer portion of A-Color 635 is changed to a belt transfer configuration, and a urethane blade for cleaning the transfer belt is provided. The image quality was evaluated by visual observation of the density unevenness of the image immediately after the start of copying and after the copying of 30,000 sheets, the presence of the photosensitive member fog, and the non-image portion fog.

(Evaluation of gloss unevenness)
Using the developer used for the evaluation of the image quality, an image is printed with a photographic chart of a front solid image, and the gloss unevenness of the fixed image when fixed at a fixing temperature of 140 ° C. is visually evaluated. ”To“ G4 ”.
G1: The fixed image has noticeable uneven glossiness, giving an overall unsightly impression.
G2: The fixed image has uneven luster in some places and was an unnatural image.
G3: Although there was some uneven luster, it was at a level with no problem.
G4: The fixed image had no uneven gloss, showed a uniform and appropriate gloss, and was a beautiful image.

<Evaluation results>
From the results shown in Table 1, in comparison with the comparative example, Examples 1 to 6 have less image quality defects due to uneven luster and the like because the base material release rate and the metal element release rate of the flocculant are small. It was confirmed that there was no offset.

Claims (3)

In an electrostatic charge image developing toner containing a binder resin, a colorant, and a metal having a valence of 2 or more,
A toner for developing an electrostatic charge image, wherein the metal having a valence of 2 or more has a base material release rate of 18% or less and a metal element release rate of 15% or less. In an electrostatic charge image developer including a toner containing a binder resin, a colorant, and a metal having a valence of 2 or more,
A developer for developing an electrostatic image, wherein the metal having a valence of 2 or more contained in the toner has a base material release rate of 18% or less and a metal element release rate of 15% or less. A latent image forming step for forming an electrostatic latent image on the surface of the latent image holding member, and development for forming the toner image by developing the electrostatic latent image formed on the surface of the latent image holding member with a developer containing toner. An image forming process including: a transfer process for transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target; and a fixing process for thermally fixing the toner image transferred on the surface of the transfer target. In the method
An image forming method, wherein the metal having a valence of 2 or more contained in the toner has a base material release rate of 18% or less and a metal element release rate of 15% or less.