JP2007086494A - Electrostatic charge image developing toner and method for manufacturing the same, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner which retains electric characteristics without impairment even when a crystalline resin is used as a binder resin in the toner, and which obviates the degradation in electrostatic chargeability and attains low-temperature fixation even when exposed to AC electric field particularly in a developing process, and to provide a method for manufacturing the same and an image forming method using the same. <P>SOLUTION: The electrostatic charge image developing toner composed of a crystal resin as a principal component of a binder resin includes a structure expressed by formula (1) in the toner in which the volume resistivity at an applied voltage 1,000V is ≥3.0x10<SP>13</SP>Ωcm and/or the dielectric loss factor at a frequency 1,000 Hz ranges from 0.001 to 0.035: M (←OOC-R)n... formula (1). In the formula (1), M denotes a bivalent or higher valence metal; ← denotes a coordinate bond; R is ≥1C functional group having any of aliphatic, alicyclic and aromatic structures; and n denotes an integer of 2 to 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  Many methods are known as electrophotographic methods. In general, a latent image is electrically formed on the surface of a photoconductor (latent image carrier) using a photoconductive substance by various means, and the formed latent image is developed with toner to form a toner image. After the toner image is formed, the toner image is transferred to a surface of a recording medium such as paper via an intermediate transfer body (in this case, included in the receiving body) and heated, pressurized, An image is formed through a plurality of steps of fixing by solvent vapor or the like. Further, the toner remaining on the surface of the photoreceptor is cleaned by various methods as necessary, and is used again for developing the toner image.

  As a fixing technique for fixing the toner image transferred to the surface of the transfer target, a hot roll fixing is performed in which the transfer target having the toner image transferred is inserted between a pair of rolls including a heating roll and a pressure roll and fixed. The law is common. As a similar technique, a fixing method in which one or both of the rolls is replaced with a belt is also known. Compared with other fixing methods, these techniques provide high-speed and robust images, high energy efficiency, and less environmental damage due to volatilization of solvents and the like.

  In recent years, demand for energy saving necessary for image formation has increased, and there has been a need to save power in a fixing process that occupies a certain amount of power. In order to increase fixing conditions (conditions in which no offset occurs) under such power saving, it is necessary to lower the toner fixing temperature. Further, by lowering the toner fixing temperature, in addition to the power saving and the expansion of the fixing conditions, a waiting time until the fixing temperature on the surface of the fixing member such as a fixing roll at the time of power input, so-called warm-up time Can be shortened and the life of the fixing member can be extended.

  As a means for lowering the toner fixing temperature, a technique for lowering the glass transition point of toner resin (binder resin) is generally performed. However, a method of simply lowering the glass transition point of the binder resin can obtain a toner that can be fixed at a low temperature, but there are practical problems such as blocking and storage stability. The fixing temperature can also be lowered by using a plasticizer, but there is a problem that toner blocking occurs during storage or in the developing machine.

  As a means for achieving both toner blocking and low-temperature fixability, a method using a crystalline resin as a binder resin is known (see, for example, Patent Documents 1 and 2). In this case, it is important that the melting point of the crystalline resin is practically designed to be 50 ° C. or higher. However, since the melting of the toner starts near the melting point, sufficient heat storage properties cannot be obtained. Further, setting the melting point to be high for the purpose of imparting heat storage properties causes an increase in fixing temperature, and it is difficult to achieve both low temperature fixing properties and heat storage properties.

Further, since the toner using the crystalline resin as described above is produced by a kneading and pulverizing method, there is a problem that pulverization is very difficult, and practicality is poor from the viewpoint of manufacturability.
Furthermore, the toner using the crystalline resin as described above has a low resistance and a high dielectric loss compared to the amorphous resin, and the toner using the AC resin is used in the development process. In particular, the charging characteristics of the toner are remarkably deteriorated, and as a result, the toner scatters to the non-image area or the image defect occurs, which is not preferable for the formation of a high-quality color image.

  As a means to solve the above problem, the crystalline resin is not used alone as the binder resin, but the technique of using the crystalline resin and the amorphous resin in combination or the crystalline resin and the amorphous resin are chemically used. Many methods using bonded resins have been proposed. It is also known that when a toner is produced by a kneading and pulverizing method, pulverization is facilitated by the presence of an amorphous resin portion (see, for example, Patent Documents 3 to 6).

  However, when the amorphous resin is more than the crystalline resin, the amorphous resin becomes a continuous phase and the crystalline resin becomes a dispersed phase. In this case, the crystalline resin is covered with the amorphous resin. Therefore, while the problem due to the crystalline resin does not occur, the melting of the entire toner is governed by the softening temperature of the amorphous resin, so that it is difficult to achieve low temperature fixability.

As described above, although it is considered effective to use a crystalline resin for lowering the fixing temperature of the toner, there are many problems to be solved regarding industrial performance and performance in practical use in an electrophotographic process. In particular, it is considered difficult to use a crystalline resin as a binder resin component of toner in an electrophotographic process of a current mainstream copying machine that uses an alternating electric field in the developing process in order to obtain high development / transfer efficiency. is the current situation.
Japanese Patent Publication No. 56-13943 Japanese Examined Patent Publication No.62-39428 Japanese Patent Laid-Open No. 2-79860 JP-A-1-163756 Japanese Patent Laid-Open No. 1-163757 JP-A-4-81770

  Therefore, an object of the present invention is to solve the above problems. That is, the present invention does not impair electrical characteristics even when a crystalline resin is used as the binder resin in the toner, and in particular, the charging property does not deteriorate even when exposed to an alternating electric field in the development process, and low temperature fixing is also possible. An object of the present invention is to provide a toner for developing an electrostatic image, a method for producing the same, and an image forming method using the same.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> An electrostatic charge image developing toner comprising a crystalline resin as a binder resin component,
The toner contains a structure represented by the following formula (1), the volume resistivity at an applied voltage of 1000 V is 3.0 × 10 ¹³ Ωcm or more, and / or the dielectric loss factor at a frequency of 1000 Hz is 0.001 to 0.001. This is an electrostatic charge image developing toner in the range of 0.035.
M (← OOC-R) n Formula (1)
In the above formula (1), M is a divalent or higher polyvalent metal, ← is a coordination bond, R is a functional group having an aliphatic, alicyclic or aromatic structure having 1 or more carbon atoms, n represents an integer of 2 to 7, respectively.

<2> an aggregation step in which at least a resin fine particle dispersion in which crystalline resin fine particles are dispersed and a colorant dispersion in which colorant particles are dispersed are mixed and heated to form aggregated particles of resin fine particles and colorant particles; A method for producing a toner for developing an electrostatic charge image, comprising: a step of fusing and aggregating the agglomerated particles by heating the agglomerated particle dispersion in which the agglomerated particles are dispersed to a temperature equal to or higher than a melting point of the resin fine particles. And
This is a method for producing a toner for electrostatic charge development, wherein a divalent or higher valent metal salt and / or a chelating agent is further mixed in the temperature raising step of the aggregation step.

<3> A latent image forming step for forming an electrostatic latent image on the surface of the latent image carrier, and a electrostatic image formed on the surface of the latent image carrier using a developer containing toner carried on the developer carrier. A developing step of developing the latent image into a toner image, a transferring step of transferring the toner image formed on the latent image carrying surface to the surface of the transfer target, and the toner image transferred to the surface of the transfer target being heated An image forming method having at least a fixing step for fixing,
An image forming method using the electrostatic image developing toner according to <1> as the toner.

<4> The image forming method according to <3>, wherein the developer carrying member is developed by applying a voltage containing an AC component as a developing bias.

  According to the present invention, even if a crystalline resin is used as the binder resin in the toner, the electrical characteristics are not impaired, and in particular, no image defects occur because the chargeability does not deteriorate even when exposed to an alternating electric field in the development process. Further, it is possible to provide a toner for developing an electrostatic latent image that can be fixed at low temperature, a method for producing the same, and an image forming method.

Hereinafter, the present invention will be described in detail.
<Toner for electrostatic image development>
The electrostatic image developing toner of the present invention is an electrostatic image developing toner (hereinafter sometimes referred to as “toner”) containing a crystalline resin as a component of a binder resin. The volume resistivity at an applied voltage of 1000 V is 3.0 × 10 ¹³ Ωcm or more, and / or the dielectric loss factor at a frequency of 1000 Hz is in the range of 0.001 to 0.035. An electrostatic charge image developing toner.
M (-OOC-R) n Formula (1)
In the above formula (1), M represents a polyvalent metal having two or more valences, ← is a coordination bond, R is a functional group having an aliphatic, alicyclic or aromatic structure having 1 or more carbon atoms. Group and n each represents an integer of 2 to 7.

  As described above, when a toner is prepared using a crystalline resin as a main component as a binder resin, pulverization is very difficult by the kneading pulverization method, and therefore, a wet manufacturing method such as an emulsion aggregation method is preferable. However, when toner particles are produced by a wet manufacturing method, the electric resistance value of the toner is lowered, and when an alternating electric field is applied as a developing bias during development, the chargeability of the toner is significantly lowered.

  The present inventors examined this cause from a viewpoint including the manufacturing process. As a result, for example, when a toner is prepared by an aggregation coalescence method using crystalline polyester as the main component of the binder resin, the carboxylic acid at the end of the crystalline polyester and the cation used as the aggregating agent form an ionic bond. As a result, it is presumed that a conductive path is formed by promoting the parallelization of the resin skeleton, which causes a decrease in the electrical resistance of the toner and the like, and in particular causes a decrease in the toner charge amount when an AC electric field is applied. It was done.

  The “main component of the binder resin” refers to a component occupying 50% by mass or more of the resin components in the binder resin.

  Under the above hypothesis, in the present invention, in the middle of the aggregation, a multi-coordination bond is formed between the carboxylic acid of the crystalline polyester and the cation of the aggregating agent so that the parallelism of the resin skeleton is moderately increased. When disturbed, it was found that the conduction path was blocked while maintaining the crystallinity necessary for the sharp melt property, and the reduction of the electrical resistance in the toner could be suppressed. That is, it has been found that a multi-coordination bond between a cation and a carboxylic acid makes it possible to produce a toner having low temperature fixability and no deterioration in electrical characteristics even under an alternating electric field.

In the present invention, the multi-coordinate bond is represented by the following formula (1), where M is the central metal. Accordingly, the toner of the present invention includes a structure represented by the following formula (1) in the toner.
M (← OOC-R) n Formula (1)

In the above formula (1), M is a divalent or higher polyvalent metal, ← is a coordination bond, R is a functional group having an aliphatic, alicyclic or aromatic structure having 1 or more carbon atoms, n represents an integer of 2 to 7. Specifically, examples of M include aluminum, iron, calcium, magnesium, manganese, cobalt, and zinc. Among these, aluminum is particularly preferable from the viewpoint of easy bond formation with carboxylic acid. Examples of R include an alkyl group as an aliphatic group, a cycloalkyl group as an alicyclic group, and a phenyl group, an alkylphenyl group, and a benzyl group as an aromatic group.
Moreover, it is preferable that n is an integer of 2-6.

  In order to introduce such a structure into the toner, in the aggregating step, only a metal salt having a valence of 2 or more may be added and reacted, or when a polyvalent metal ion is present in the system. Only a chelating agent may be added, and both the metal salt and the chelating agent may be added and reacted.

The structure represented by the formula (1) is preferably contained in the toner in an amount of 0.01 to 5% by mass, and more preferably 0.05 to 4% by mass. If it is less than 0.01% by mass, the parallelism of crystals may not be disturbed to the extent that the conduction path can be interrupted. If it exceeds 5% by mass, the crystallinity is too low and the melting point of the toner may be lowered.
The structure (coordination bond) represented by the formula (1) contained in the toner can be confirmed by the presence or absence of a chemical shift in the C ¹³ signal of NMR.

  On the other hand, the formation of the conductive path correlates with a decrease in the volume resistivity and / or an increase in the dielectric loss factor of the toner, so that multi-coordinate bonds are introduced into the toner (binder resin) as described above. Therefore, it is necessary to make the volume resistivity and / or the dielectric loss ratio of the toner fall within a range where the chargeability is not lowered.

As a result of intensive studies by the present inventors, the volume resistivity needs to be 3.0 × 10 ¹³ Ωcm or more at an applied voltage of 1000 V, and the dielectric loss factor is 0.001 to 0.035 at a frequency of 1000 Hz. It was found that it was necessary to be in the range.
The above-mentioned conditions only need to be satisfied for either volume resistivity or dielectric loss factor, and of course, both may be satisfied.

If the volume resistivity at the time of 1000V application is less than 3.0 × 10 ¹³ Ωcm, charge injection tends to occur under an alternating electric field in the development process, or charge leakage occurs when the developer is left unstirred. It becomes easy to do, and deterioration of an electrical property becomes remarkable. The volume resistivity is preferably in the range of 3.0 × 10 ^{13 to} 5.0 × 10 ¹⁵ Ωcm, and more preferably in the range of 1.0 × 10 ^{14 to} 5.0 × 10 ¹⁵ Ωcm.

On the other hand, when the dielectric loss factor at 1000 Hz exceeds 0.035, similarly, charge injection is likely to occur under an alternating electric field in the development process, or charge leakage is likely to occur when the developer is left unstirred. However, the deterioration of electrical characteristics becomes remarkable. In the case of resin, the dielectric loss factor is less than 0.001 in practice. The dielectric loss factor is preferably in the range of 0.001 to 0.030, and more preferably in the range of 0.001 to 0.020.
In addition, the measuring method of the said volume resistivity and a dielectric loss factor is mentioned later.

Next, the configuration of the electrostatic image developing toner of the present invention will be described.
The binder resin in the present invention contains a crystalline resin as a component. The crystalline resin refers to a resin having a clear endothermic peak rather than a stepwise endothermic amount change in differential scanning calorimetry (DSC).

  The crystalline resin is not particularly limited as long as it is a resin having crystallinity, and specific examples include crystalline polyesters and crystalline vinyl resins. From the viewpoint of adjusting the melting point within a preferable range, a crystalline polyester is preferable. A linear aliphatic crystalline polyester having an appropriate melting point is more preferred.

The crystalline polyester is 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.
The method for producing the crystalline polyester is not particularly limited and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. Examples thereof include direct polycondensation and transesterification. Depending on the type of monomer, it can be used separately.

  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.

  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 there are sulfonic acid groups, as described later, emulsification or suspension can be performed without using a surfactant.

  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 deteriorates. On the other hand, when the content exceeds 15 mol%, not only the crystallinity of the polyester resin is lowered, but also the process of fusing the particles after aggregation is adversely affected. There is a problem that it is difficult to adjust the diameter.

  Furthermore, it is more preferable to contain a dicarboxylic acid component having a double bond in addition to the aforementioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid. 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.

  As the polyhydric alcohol component, 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 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, 1,12-dodecanediol, 1,13 -Tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol and the like are exemplified, but not limited thereto. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable in view of availability.

  Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like. These may be used individually by 1 type and may use 2 or more types together.

Among the polyhydric alcohol components, the content of the aliphatic diol component is preferably 80 mol% or more, and more preferably 90% or more. If the content of the aliphatic diol component is less than 80 mol%, 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. is there.
If necessary, monovalent acids such as acetic acid and benzoic acid, and monovalent alcohols such as cyclohexanol and benzyl alcohol can be used for the purpose of adjusting the acid value and the hydroxyl value.

  Moreover, the crystalline polyester as described above means a polymer (copolymer) obtained by polymerizing a component constituting polyester and other components in addition to a polymer having a 100% polyester structure as a constituent component. To do. However, in the latter case, the component other than the polyester constituting the polymer (copolymer) is 50% by mass or less.

  On the other hand, the crystalline vinyl resin includes, as monomers, amyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, ( (Meth) acrylic acid decyl, (meth) acrylic acid undecyl, (meth) acrylic acid tridecyl, (meth) acrylic acid myristyl, (meth) acrylic acid cetyl, (meth) acrylic acid stearyl, (meth) acrylic acid oleyl, (meta) ) Vinyl resins using long-chain alkyls such as behenyl acrylate, alkenyl (meth) acrylates, and the like. In the above, the description “(meth) acryl” means that both “acryl” and “methacryl” are included.

  As melting | fusing point of the crystalline resin in this invention, Preferably it is the range of 50-120 degreeC, More preferably, it is the range of 60-110 degreeC. If the melting point is lower than 50 ° C., the storage stability of the toner and the storage stability of the toner image after fixing may become a problem. On the other hand, when the temperature is higher than 120 ° C., sufficient low-temperature fixing may not be obtained as compared with conventional toners.

  In addition, the melting point of the toner of the present invention having a binder resin as a main component is preferably in the range of 45 to 110 ° C., and more preferably in the range of 60 to 90 ° C. Since the toner sharply decreases in viscosity at the boundary of the melting point, blocking occurs when the toner is stored in a temperature environment equal to or 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 110 ° C., low-temperature fixing may not be possible.

  A differential scanning calorimeter (manufactured by Perkin Elmer, DSC-7) can be used to measure the melting point of the crystalline resin and toner. The temperature correction of the detection part of this apparatus uses the melting point of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. The sample used was an aluminum pan, an empty pan was set as a control, and melting by differential scanning calorimetry shown in ASTM D3418-8 was performed at a heating rate of 10 ° C / min from room temperature to 150 ° C. It can be determined as the peak temperature. The crystalline resin may show a plurality of melting peaks. In the present invention, the maximum peak is regarded as the melting point.

  In the present invention, “crystallinity” means that the differential scanning calorimetry has a clear endothermic peak rather than a stepwise endothermic amount change as described above. It means that the half-value width of the endothermic peak when measured at ° C./min is within 6 ° C. On the other hand, a resin having a half-value width exceeding 6 ° C. or a resin in which no clear endothermic peak is observed means an amorphous resin, but as an amorphous resin used in the present invention described later, a clear endothermic peak is used. It is preferable to use a resin that does not show the above.

The binder resin in the present invention only needs to contain the crystalline resin as a main component, and may contain an amorphous resin in addition to this.
Examples of the amorphous resin include conventionally known thermoplastic binder resins. Specifically, homopolymers or copolymers of styrenes such as styrene, parachlorostyrene, and α-methylstyrene ( Styrene resin); methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, methacryl Homopolymers or copolymers of vinyl groups such as lauryl acid and 2-ethylhexyl methacrylate (vinyl resins); Homopolymers or copolymers of vinyl nitriles such as acrylonitrile and methacrylonitrile (vinyl) Resins); vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether Homopolymers or copolymers of ters (vinyl resins); homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone (vinyl resins); ethylene, propylene, Homopolymers or copolymers of olefins such as butadiene and isoprene (olefin resins); non-vinyl condensation resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and the like Examples thereof include graft polymers of 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 and polyester resins are particularly preferable.

  In the case of a vinyl resin, it is advantageous in that a resin 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. Examples include monomers that are raw materials.

  On the other hand, when a polyester resin is used as the amorphous resin in the toner of the present invention, the resin particle dispersion can be easily prepared by emulsifying and dispersing the resin by adjusting the acid value or using an ionic surfactant. It is advantageous in that it can be prepared. The amorphous polyester resin used for emulsification dispersion is synthesized by dehydration condensation of polyvalent carboxylic acid and polyhydric alcohol.

  Examples of polyvalent carboxylic acids include terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, and other aromatic carboxylic acids, maleic anhydride, fumaric acid, succinic acid, alkenyl Examples thereof include aliphatic carboxylic acids such as succinic anhydride and adipic acid, and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. These polyvalent carboxylic acids can be used alone or in combination. Of these polyvalent carboxylic acids, it is preferable to use aromatic carboxylic acids, and in order to take a crosslinked structure or a branched structure in order to ensure good fixability, tricarboxylic or higher carboxylic acids (trimerits) It is preferable to use an acid or an acid anhydride thereof in combination.

  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.

  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.

  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 addition amount of such a catalyst is preferably 0.01 to 1% by mass with respect to the total amount of raw materials.

  The acid value (mg number of KOH necessary for neutralizing 1 g of resin) of the polyester resin (similar to crystalline polyester) makes it easy to obtain the desired molecular weight distribution, and the granulation property of the toner particles by the emulsion dispersion method. It is preferably 1 to 30 mgKOH / g because it is easy to ensure and the environmental stability of the obtained toner (the stability of chargeability when the temperature and humidity change) is easily maintained. . The acid value of the polyester resin can be adjusted by controlling the carboxyl group at the terminal of the polyester according to the blending ratio of the raw polyhydric carboxylic acid and polyhydric alcohol and the reaction rate. Or what has a carboxyl group in the principal chain of polyester is obtained by using trimellitic anhydride as a polyvalent carboxylic acid component.

  In the present invention, the main component (50% by mass or more) of the binder resin is a crystalline resin. However, from the viewpoint of design balance such as low-temperature fixing characteristics and toner strength, a crystalline resin having sharp melt properties and an amorphous property are used. It is also possible to use a mixed system with a resin. In this case, the melting point or glass transition temperature of the binder resin is preferably in the range of 45 to 110 ° C, and more preferably in the range of 60 to 90 ° C. The mixing ratio is determined from the relationship between the melting point of the crystalline resin and the glass transition temperature of the amorphous resin. It is important to select a resin component that does not hinder the fixability.

  When an amorphous resin is included, the ratio between the crystalline resin and the amorphous resin (crystalline / amorphous) is preferably in the range of 50/50 to 95/5 in mass ratio. In order to obtain the fixing property, it is preferably in the range of 60/40 to 95/5.

In the present invention, as will be described later, the toner particles contain a chelating agent as necessary.
The chelating agent used is preferably water-soluble. If it is not water-soluble, the dispersibility in the liquid is poor, and the metal ions cannot be sufficiently captured in the toner.

  The chelating agent is not particularly limited as long as it is a known water-soluble chelating agent. For example, oxycarboxylic acids such as tartaric acid, citric acid and gluconic acid, iminodiacid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid ( EDTA) and the like can be preferably used. Among these, EDTA is preferably used because it does not cause deterioration of the electrical characteristics and various characteristics of the toner.

  The addition amount of the chelating agent is preferably in the range of 0.0001 to 1 part by mass, more preferably in the range of 0.001 to 0.5 part by mass with respect to 100 parts by mass of the binder resin. When the addition amount of the chelating agent is less than 0.0001 parts by mass, there is no effect of adding the chelating agent, and when exposed to an alternating electric field, charge injection is likely to occur and the development / transfer efficiency may be reduced. On the other hand, if it exceeds 1 part by mass, it is difficult to cause charge injection even under an alternating electric field, but it adversely affects the chargeability, and the viscoelasticity of the toner changes dramatically, resulting in low-temperature fixability and image glossiness. May have adverse effects.

  The chelating agent used in the present invention is added in the aggregation step in the toner production described later, but it is not particularly necessary to adjust the temperature of the solution. Even if it is added at room temperature, it is adjusted to the temperature in the tank in the aggregation step. You can add either.

(Other ingredients)
The colorant used in the toner of the present invention is not particularly limited as long as it is a known colorant. For example, carbon black such as furnace black, channel black, acetylene black, thermal black, bengara, bitumen, titanium oxide, etc. 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.

  In addition, 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 red 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.

  The content of the colorant in the toner of the present invention is preferably in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the binder resin, and if necessary, a surface-treated colorant is used. 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.

  The release agent used in 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, low molecular weight polypropylene, and low molecular weight polyethylene. , Sazol wax, microcrystalline wax, Fischer-Tropsch wax, paraffin wax, montan wax and the like, or mineral / petroleum wax, fatty acid ester, montanic acid ester, etc. It is not a thing. 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 60 ° C. or higher, more preferably 70 ° C. or higher, from the viewpoint of storage stability. Further, from the viewpoint of offset resistance at low temperatures, it is preferably 110 ° C. or lower, and more preferably 100 ° C. or lower. Furthermore, from the viewpoint of offset resistance at high temperatures, a release agent having a melting point of 100 ° C. or higher can be used in combination.

  The content of the release agent is preferably in the range of 1 to 30 parts by mass and more preferably in the range of 2 to 20 parts by mass with respect to 100 parts by mass of the binder resin. When the content of the release agent is less than 1 part by mass, there is no effect of addition of the release agent, which may cause hot offset at a high temperature. On the other hand, if it exceeds 30 parts by mass, the chargeability 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 tends to remain in a fixed image, which may cause a problem that OHP transparency is deteriorated.

In addition, if necessary, a lubricant or a charge control agent may be added to the toner of the present invention.
Examples of the lubricant that can be used include fatty acid amides such as ethylene bisstearylamide and oleic acid amide, and fatty acid metal salts such as zinc stearate and calcium stearate.

  The charge control agent is added to improve and stabilize the chargeability. For example, a dye composed of a complex such as a quaternary ammonium salt compound, a nigrosine compound, aluminum, iron, or chromium, or a triphenylmethane type Various commonly used charge control agents such as pigments can be used, but this affects the stability of the aggregated particles in the aggregation process and fusion / unification process when the toner is prepared by the emulsion aggregation method described later. From the standpoint of controlling ionic strength and reducing wastewater contamination, materials that are difficult to dissolve in water are preferred.

  In particular, as the charge control agent, metal salts of benzoic acid, metal salts of salicylic acid, metal salts of alkyl salicylic acid, metal salts of catechol, metal-containing bisazo dyes, tetraphenylborate derivatives, and the like used in powder toners. A compound selected from the group consisting of a quaternary ammonium salt and an alkylpyridinium salt, and a combination thereof can be preferably used.

  Further, when inorganic fine particles are added to the toner as a charge control agent, examples of such inorganic fine particles include silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate and the like, which are usually outside the surface of the toner. Listed are all inorganic fine particles used as an additive. In this case, these inorganic fine particles can be used by being dispersed in a solvent using an ionic surfactant, a polymer acid, a polymer base or the like.

  Furthermore, as internal additives, those that can be added mainly by a wet method, such as metals such as ferrite, magnetite, reduced iron, cobalt, nickel, manganese, alloys, or magnetic materials such as compounds containing these metals, etc. Is mentioned.

In the toner of the present invention, inorganic fine particles or organic fine particles can be added to the surface by applying a shearing force in a dry state for the purpose of use as a flow aid or a cleaning aid.
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. , Bengala, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride and the like. 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 mass with respect to 100 parts by mass of the toner.
The organic fine particles are generally used for the purpose of improving cleaning properties and transfer properties. Specific examples include polystyrene, polymethyl methacrylate, polyvinylidene fluoride, and the like.

  The volume average particle size of the toner of the present invention is preferably in the range of 3 to 9 μm, and more preferably in the range of 3 to 8 μm. When the volume average particle diameter of the toner particles exceeds 9 μm, the ratio of coarse particles increases, and the reproducibility and gradation of fine lines and fine dots of the image obtained through the fixing process are lowered. On the other hand, when the volume average particle size of the toner particles is less than 3 μm, the powder fluidity, developability, or transferability of the toner deteriorates, and the cleaning property of the toner remaining on the surface of the image carrier decreases. Various problems occur in other processes due to the deterioration of characteristics.

  Further, as the particle size distribution index of the toner particles used in the present invention, the volume average particle size distribution index GSDv is preferably 1.30 or less, and the ratio GSDv / GSDp to the number average particle size distribution index GSDp is 0.95 or more. It is more preferable that When the volume distribution index GSDv exceeds 1.30, the resolution decreases, and when the ratio of the volume average particle size distribution index GSDv to the number average particle size distribution index GSDp is less than 0.95, a decrease in chargeability occurs. At the same time, it may scatter and cause image defects such as fog.

The volume average particle size and the particle size distribution index were measured and calculated as follows. First, the volume and number of individual toner particles are accumulated from the smaller diameter side with respect to the divided particle size range (channel) of the toner particle size distribution measured using a Coulter Counter TAII (manufactured by Beckman-Coulter) as a measuring device. Draw a distribution and define the particle size to be 16% cumulative as the volume average particle size D16v and the number average particle size D16p. The particle size to be 50% cumulative is the volume average particle size D50v (this value is the volume average particle size And D50p. Similarly, the particle diameters with an accumulation of 84% are defined as volume average particle diameters D84v and D84p. Using these, the volume average particle size distribution index GSDv is defined as (D84v / D16v) ^1/2 , and the number average particle size distribution index GSDp is defined as (D84p / D16p) ^1/2 .

Further, the toner shape factor SF1 in the present invention is preferably in the range of 110 to 140.
By setting the shape factor SF1 in the range of 110 to 140, it is easy to increase the shell coverage in the core / shell structure.

Here, the shape factor SF1 is obtained by the following equation (2).
SF1 = (ML ² / A) × (π / 4) × 100 (2)
In the above formula (2), ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.

  The SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and can be calculated as follows, for example. That is, an optical microscope image of the toner spread on the surface of the slide glass is taken into a Luzex image analyzer through a video camera, the maximum length and projected area of 100 toner particles are obtained, calculated by the above equation (2), and the average value thereof Is obtained.

The toner particles in the present invention can be produced by any production method such as a kneading and pulverization method, a suspension polymerization method, a dissolution suspension method, and an emulsion aggregation coalescence method as long as the multi-coordination bond can be introduced into the crystalline resin. However, the emulsion aggregation and coalescence method is particularly preferable as a production method that satisfies the above requirements because it can efficiently introduce multi-coordination bonds in the crystalline resin.
A method for producing the toner for developing an electrostatic charge image of the present invention by the emulsion aggregation method will be described later.

<Method for producing toner for developing electrostatic image>
The method for producing a toner for developing an electrostatic charge image according to the present invention comprises mixing a resin fine particle dispersion in which at least crystalline resin fine particles are dispersed and a colorant dispersion in which colorant particles are dispersed, and raising the temperature. An aggregating step of forming aggregated particles with the particles, and an aggregating step of fusing and coalescing the aggregated particles by heating the aggregated particle dispersion in which the aggregated particles are dispersed to a temperature equal to or higher than the melting point of the resin fine particles. A method for producing a toner for developing an electrostatic charge image, wherein a metal salt having a valence of 2 or more and / or a chelating agent is further mixed in the temperature raising step of the aggregation step.
Such an emulsion aggregation and coalescence method is preferable in that it enables precise structure control in a crystalline resin such as the toner of the present invention.

  Specifically, a resin fine particle dispersion obtained by dispersing resin fine particles produced by emulsion polymerization or the like with an ionic surfactant is used, and a colorant dispersion or the like dispersed with an ionic surfactant opposite to this is used. Mix to give heteroaggregation. Next, the agglomerated particles are formed by agglomerating them, and then the aggregates are fused by heating above the melting point of the crystalline resin or the glass transition point of the amorphous resin usually contained in the agglomerated particles. It is a method of uniting, washing and drying.

  As a specific method for producing the toner of the present invention as described above, an additive that forms a bond represented by M (-OOC-R) n with the metal M ion of the flocculant during the aggregation process is preferable. Used for. As this additive, a chelating agent is used, and the multi-coordination to the extent that the parallelism of the resin skeleton is moderately disturbed in the toner by capturing the metal ion in the flocculant by the multi-coordination bond with the carboxylic acid. A chelate compound having a bond can be formed.

  In the case where a carboxyl group is present at the end of the crystalline resin as described above, and a multi-coordination bond is formed by the metal ion of the flocculant and the divalent or higher-valent metal salt added as necessary. The chelating agent may not be added. Moreover, in this invention, in order to make the said multi-coordination bond exist effectively, you may add both a chelating agent and a metal salt.

As the chelating agent, a water-soluble chelating agent is preferably used. When a hydrophobic additive is used, not only the aggregation is insufficient, but the parallelism of the crystalline resin cannot be appropriately disturbed, and desired electrical characteristics may not be obtained.
Specific examples of the chelating agent used in the present invention are as described above.

  First, a resin fine particle dispersion of a crystalline resin can be obtained by publicly known phase inversion emulsification, or by heating to a melting point or higher and emulsifying by mechanical shearing force. At this time, an ionic surfactant or the like may be added. When amorphous resin fine particles are used, it is preferable to use the same method as that for producing the crystalline resin fine particles. However, when emulsion polymerization such as styrene-acrylic resin is possible, it is prepared by emulsion polymerization or the like. The resin fine particles are prepared by dispersing them in a solvent using an ionic surfactant or the like.

  In addition, the colorant dispersion uses a ionic surfactant having a polarity opposite to that of the ionic surfactant used in the preparation of the resin fine particle dispersion, and the colorant particles having a desired color such as blue, red, and yellow are used as solvents. Prepare by dispersing in. Furthermore, the release agent dispersion liquid is a homogenizer that disperses the release agent in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid, or a polymer base, and heats above the melting point and applies strong shear. Or by making fine particles with a pressure discharge type disperser.

The resin fine particle diameter of the resin fine particle dispersion in the present invention is 1 μm or less in volume average particle diameter, preferably in the range of 100 to 300 nm. When the volume average particle size exceeds 1 μm, the particle size distribution of the toner particles obtained by agglomeration and fusion is widened, or free particles are generated, leading to a decrease in toner performance and reliability. If it is less than 100 nm, it may take time to coagulate and grow the toner, which may not be industrially suitable. If it exceeds 300 nm, the dispersion of the release agent and the colorant becomes non-uniform and control of the toner surface properties. May be difficult.
The particle diameter of the resin fine particle dispersion or the like can be measured, for example, with a laser diffraction particle size distribution measuring device (LA-700, manufactured by Horiba, Ltd.).

  In the aggregation step, the resin fine particle dispersion, the colorant dispersion, and, if necessary, the particles in the release agent dispersion are aggregated to form aggregated particles. This process may be performed by mixing and agglomerating the dispersions all at once, but may include the following adhesion step.

  That is, in the agglomeration step, the initial balance of the amount of each ionic dispersant of each polarity is shifted in advance, and this is ionically neutralized using a polymer of an inorganic metal salt such as polyaluminum chloride, Alternatively, after forming and stabilizing the first stage matrix aggregation below the glass transition point, as a second stage, add a resin fine particle dispersion treated with a dispersing agent having a polarity and amount so as to compensate for the balance deviation, Furthermore, if necessary, after heating at a temperature slightly lower than the melting point or glass transition temperature of the resin fine particles of the resin contained in the matrix or additional particles, the particles are stabilized at a higher temperature to form adhered particles (attachment step). Next, the resin fine particles added in the second stage of agglomeration by heating to the melting point or the glass transition temperature or higher are combined together while adhering to the surface of the base agglomerated particles. Furthermore, the stepwise operation of aggregation may be repeated several times.

  As the aggregating agent used in the aggregating step, a surfactant having an opposite polarity to the surfactant used for each of the dispersants, an inorganic metal salt, and a divalent or higher-valent metal complex can be preferably used. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Of these, aluminum salts and polymers thereof are particularly preferred. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more suitable.
Moreover, it is preferable to add these inorganic metal salts so that the density | concentration may be in the range of 0.11-0.25 mass%.

  In the present invention, a divalent or higher valent metal salt and / or chelating agent is further mixed in the temperature raising step of the aggregation process. Mixing metal salts, etc. at this stage is particularly likely to cause rearrangement of the crystalline resin at this point, so metal salts and chelating agents are introduced to form multi-coordination bonds, thereby making the resin skeleton parallel. This is because it is effective in disturbing and blocking the conduction path.

  The temperature in the temperature raising stage is preferably in the range of 40 to 70 ° C, more preferably in the range of 45 to 65 ° C. If the temperature is less than 40 ° C., the rearrangement may not start. If the temperature exceeds 70 ° C., the rearrangement may be terminated.

  The reason why the metal salt having a valence of 2 or more is added at this stage is to supplement the amount of metal ions when the amount of multi-coordination bonds formed by the metal ions added to the system as the flocculant is not sufficient. . Therefore, the same metal salt as the metal salt used as the flocculant is preferably used as the metal salt, and these may be used in combination of two or more.

  The metal salt is preferably divalent to trivalent, more preferably trivalent to tetravalent, and particularly preferably aluminum chloride or aluminum sulfate. Moreover, the addition amount of the metal salt is preferably in the range of 0.01 to 1% by mass, and more preferably in the range of 0.01 to 0.5% by mass with respect to the total amount of the mixed dispersion.

  Further, at this stage, the chelating agent is added more in the crystalline resin by forming a complex with a metal ion added to the system as the aggregating agent or a metal ion based on the further added metal salt. This is to introduce a multi-coordination bond.

  Preferred chelating agent species are as described above. Further, the addition amount of the chelating agent at this stage is preferably in the range of 0.01 to 1% by mass, and in the range of 0.01 to 0.5% by mass with respect to the total amount of the mixed dispersion. It is more preferable.

  Further, when both the metal salt and the chelating agent are added, the mass ratio (A / B) between the addition amount A of the metal salt and the addition amount B of the chelating agent is in the range of 1/10 to 4/10. It is preferable.

Aggregated particles are formed by adding a flocculant at room temperature under stirring with a rotary shearing homogenizer to make the pH of the raw material dispersion acidic.
Further, in the aggregation step, it is preferable to adjust pH at the stage of stirring and mixing at room temperature and to add a dispersion stabilizer as necessary in order to suppress rapid aggregation due to heating.

  After the desired particle size and particle size distribution are adjusted in the aggregation step, the aggregation particles are united in the fusion step. In the fusing step, under the same stirring as in the agglomeration step, the pH of the suspension of the agglomerated particles is set in the range of 3 to 7, thereby stopping the agglomeration and heating at a temperature equal to or higher than the melting point of the crystalline resin. To fuse and coalesce the aggregated particles. The heating time may be as long as coalescence is sufficiently performed, and may be performed for about 0.2 to 10 hours. Thereafter, the temperature is lowered to a temperature lower than the crystallization temperature of the crystalline resin to solidify the obtained toner particles.

Then, the toner particle dispersion is filtered, and the dispersant is removed from the filtered toner particles with an aqueous solution of strong acid such as hydrochloric acid, sulfuric acid, nitric acid, etc., and then rinsed with ion exchange water until the filtrate becomes neutral. Desired toner particles are obtained through the washing step, the solid-liquid separation step, and the drying 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. It is desirable that the toner particles have a moisture content after drying of 1.0% or less, 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.

<Image forming method>
The image forming method of the present invention is formed on the surface of the latent image carrier using a latent image forming step of forming an electrostatic latent image on the surface of the latent image carrier and a developer carried on the developer carrier. A developing process for developing the electrostatic latent image to form a toner image, a transfer process for transferring the toner image formed on the surface of the latent image carrier to the surface of the transfer target, and the image transferred to the surface of the transfer target And a fixing step for heat-fixing the toner image, and the developer containing the electrostatic latent image developing toner of the present invention is used as the developer.

  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 carrier, 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 adhered 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 onto the surface of the transfer medium is thermally fixed by a fixing device (fixing step), and a final toner image is formed.

  In the case where a secondary transfer process using an intermediate transfer body is included, the transfer body includes an intermediate transfer body. Further, in the case of heat fixing by the fixing device, in order to prevent an offset or the like, a release agent is usually supplied to a fixing member in the fixing device.

  In the present invention, in the development step, from the viewpoint of development efficiency, image graininess, gradation reproducibility, etc., a bias potential (development bias) in which an alternating current component is superimposed on a direct current component may be applied to the developer carrier. preferable. Specifically, when the developer carrier DC applied voltage Vdc is −300 to −700 V, the developer carrier AC voltage peak width Vp-p is preferably in the range of 0.5 to 2.0 kV.

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 object is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with a resin or the like, art paper for printing Etc. can be used suitably.

  Since the image forming method of the present invention uses the developer containing the toner of the present invention, low-temperature fixing is possible, and the toner maintains an appropriate triboelectric charge amount even in a development process using an alternating electric field. Can do. For this reason, it is possible to stably provide a high-quality image particularly when forming a full-color image.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these Examples at all. In the following description, “part” represents “part by mass” and “%” represents “% by mass” unless otherwise specified.

<Measuring method of various characteristics>
First, methods for measuring physical properties of toners and the like used in Examples and Comparative Examples will be described.
(Toner particle size and particle size distribution measurement method)
In the present invention, the toner particle size and particle size distribution were measured using a Coulter Counter TA-II type (manufactured by Beckman-Coulter) as the measuring device, and ISOTON-II (manufactured by Beckman-Coulter) as the electrolyte.

  As a measurement method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, as a dispersant. This was added to 100 to 150 ml of the electrolytic solution. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of particles of 2 to 60 μm is measured using the Coulter counter TA-II type with an aperture diameter of 100 μm. The volume average particle diameter, GSDv, and GSDp were determined as described above. The number of particles to be measured was 50,000.

(Toner shape factor SF1 measurement method)
The toner shape factor SF1 is obtained by taking an optical microscope image of toner dispersed on a slide glass into a Luzex image analyzer through a video camera, and calculating the square of the maximum length of ten toners (ML ² ) and the projected area (A). The shape factor SF1 of each toner obtained by the following formula is calculated, and the average value is obtained.
SF1 = (ML ² / A) × (π / 4) × 100 (π is the circumference)

(Measurement method of molecular weight and molecular weight distribution of resin)
In the present invention, the molecular weight and molecular weight distribution of the binder resin and the like are those obtained under the following conditions. GPC uses “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)” apparatus, and column uses “TSKgel, SuperHM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation)”. THF (tetrahydrofuran) was used as an eluent. As experimental conditions, an experiment was performed using a sample concentration of 0.5%, a flow rate of 0.6 ml / min, a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

(Volume average particle diameter of resin fine particles, colorant particles, etc.)
Volume average particle diameters of resin fine particles, colorant particles, and the like were measured with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.).

(Measuring method of melting point and glass transition temperature of resin)
The glass transition point (Tg) of the amorphous resin and the melting point (Tm) of the crystalline resin were measured using a differential scanning calorimeter (manufactured by Mac Science: DSC3110, thermal analysis system 001) according to ASTM D3418-8. It was determined by measuring from room temperature to 150 ° C. under a temperature rising rate of 10 ° C./min. The glass transition point was the temperature at the intersection of the extension line of the base line and the rising line in the endothermic part, and the melting point was the temperature at the apex of the endothermic peak.
Points (Tg) are indicated.

(Electrical characteristics evaluation)
-Volume resistivity-
Using a compression molding machine (BRIQUETING PRESS) manufactured by Maekawa Test Instruments Co., Ltd., 6 g of toner was compressed with a load of 10 t and a pressurization of 60 seconds to obtain a molding disk having a diameter of 50 mm and a thickness of 3.0 mm. Using this disc as a measurement sample, volume resistivity was measured with an applied voltage of 1000 V using a digital super resistance / microammeter R8340A manufactured by Advantest Corporation. In calculating the volume resistivity, the measurement was repeated 5 times to obtain an average value, and then the correction was made based on the disc thickness and the probe diameter.

-Dielectric loss factor-
Using a disk similar to the above as a measurement sample, the measurement conditions are set to an AC frequency of 1000 Hz, and the number of repeated measurements is set to 100 using a dielectric property measuring machine (WAYNE PRECISION COMPONENT ANALYZER) manufactured by Toyo Technica, and the dielectric loss factor is measured. Carried out. Regarding the measurement, the measurement was repeated 100 times under the above conditions, and the average value was adopted as the value of the dielectric loss factor.

<Production of toner particles>
(Preparation of each dispersion)
-Crystalline resin fine particle dispersion (1)-
To a heat-dried three-necked flask, 1500 parts (92.5 mol%) of dimethyl sebacate and 118 parts (7.5 mol%) of 5-t-butylisophthalic acid and 441 parts of ethylene glycol (2 mol times the acid component) Amount) and 0.19 part of Ti (OBu) ₄ as catalyst (0.012% with respect to the acid component), and then the pressure in the container is reduced by a pressure reducing operation, and further inert by nitrogen gas. The atmosphere was refluxed at 180 ° C. for 5 hours with mechanical stirring. Then, excess ethylene glycol was removed by distillation under reduced pressure, the temperature was gradually raised to 230 ° C. and stirred for 2 hours. When the mixture became viscous, the molecular weight was confirmed by GPC, and the weight average molecular weight was 23,000. At that time, distillation under reduced pressure was stopped and air-cooled to obtain crystalline polyester (1).
The melting point of this crystalline polyester was 65 ° C.

  Next, 160 parts of this crystalline polyester (1) and 1440 parts of deionized water were placed in a stainless beaker, placed in a warm bath, and heated to 95 ° C. When the crystalline polyester was melted, the mixture was stirred at 8000 rpm using a homogenizer (manufactured by IKA, Ultra Turrax T50). Subsequently, the emulsion was dispersed while dropping 15 parts of an aqueous solution obtained by diluting 1.6 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK), and the crystallinity having a volume average particle size of 0.15 μm. A resin fine particle dispersion (1) (resin particle concentration: 20%) was prepared.

-Crystalline resin fine particle dispersion (2)-
To a heat-dried three-necked flask, 1500 parts of 1,10 dodecanedioic acid (90.5 mol%), 33.8 parts (2 mol%) of sodium dimethyl-5-sulfonate, and 106 parts of 5-t-butylisophthalic acid ( 7.5 mol%) acid component, 1,9-nonanediol 1020 parts (100 mol%), and Ti (OBu) ₄ 0.20 parts (0.014% with respect to the acid component) as a catalyst. After that, the air in the container was depressurized by a depressurization operation, and was further brought into an inert atmosphere with nitrogen gas, and refluxed at 180 ° C. for 5 hours with mechanical stirring. Then, excess ethylene glycol was removed by distillation under reduced pressure, the temperature was gradually raised to 220 ° C. and stirred for 4 hours. When the mixture became viscous, the molecular weight was confirmed by GPC, and the weight average molecular weight was 25,000. At that point, distillation under reduced pressure was stopped and air-cooled to obtain crystalline polyester (2).
The melting point of the crystalline polyester (2) was 72 ° C.

  Next, 80 parts of this crystalline polyester (2) and 720 parts of deionized water are placed in a stainless beaker, placed in a warm bath and heated to 95 ° C. When the crystalline polyester is melted, the mixture is stirred at 8000 rpm using a homogenizer (manufactured by IKA, Ultra Turrax T50). Next, while 20 parts of an aqueous solution obtained by diluting 1.6 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK) is added dropwise, the mixture is emulsified and dispersed, and has a volume average particle size of 0.15 μm. A polyester resin dispersion (2) (resin particle concentration: 10%) was prepared.

-Amorphous resin fine particle dispersion (1)-
-Bisphenol A ethylene oxide adduct (average number of moles added 2.2): 450 parts-Trimethylolpropane: 499 parts-Terephthalic acid: 1624 parts The above components are stirred, a nitrogen inlet tube, a temperature sensor, and a rectifying column. The above-mentioned monomer was charged into a 5 liter flask equipped with the above, the temperature was raised to 190 ° C. over 1 hour, and after confirming that the reaction system was uniformly stirred, 1 dibutyltin oxide was added. .2 parts were added. Further, while distilling off the generated water, the temperature was increased to 240 ° C. over 6 hours from the same temperature, and the dehydration condensation reaction was continued at 240 ° C. for another 3 hours. The acid value was 6.0 mgKOH / g, the softening point. The reaction was allowed to reach 105 ° C. Next, the temperature was lowered to 190 ° C., 580 parts of phthalic anhydride was gradually added, the reaction was continued for 1 hour at the same temperature, and an amorphous polyester having an acid value of 21 mg KOH / g and a weight average molecular weight of 32,000 was obtained. Obtained.
The glass transition point (Tg) of this amorphous polyester was 64 ° C.

Subsequently, this was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. Separately prepared aqueous medium tank is filled with 0.37% dilute aqueous ammonia diluted with reagent-exchanged ammonia water with ion-exchanged water, heated at 120 ° C. with a heat exchanger at a rate of 0.1 liter per minute, Simultaneously with the polyester resin melt, it was transferred to the Cavitron (Eurotech Co., Ltd.). A Cavitron was operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² , and an amorphous resin fine particle dispersion (1) (resin particles) made of an amorphous polyester resin having a volume average particle size of 0.14 μm Concentration: 30%).

-Colorant dispersion-
Cyan pigment (Daiichi Seika Co., Ltd., CI Pigment Blue 15: 3 (copper phthalocyanine)): 100 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R): 5 parts Exchanged water: 300 parts or more are mixed, dissolved, and dispersed for about 1 hour using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006) to disperse the colorant (cyan pigment). A colorant dispersion was prepared. The volume average particle size of the colorant (cyan pigment) in the colorant dispersion was 0.11 nm, and the colorant particle concentration was 22.0%.

-Release agent dispersion-
-Ester wax (Nippon Yushi Co., Ltd., WEP-2, melting point: 65 ° C): 250 parts-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 25 parts-Ion-exchanged water: 1000 The above is heated to 95 ° C. and dispersed using a homogenizer (manufactured by IKA, Ultra Tarrax T50), and then dispersed with a Manton Gorin high-pressure homogenizer (Gorin), and the volume average particle size is 260 nm. A release agent dispersion liquid (release agent concentration: 20%) prepared by dispersing the release agent was prepared.

(Manufacture of toner particles)
-Toner particles (1)-
Crystalline resin fine particle dispersion (1): 3000 parts Colorant dispersion: 65 parts Release agent dispersion: 150 parts Aluminum sulfate: 1.44 parts Calcium chloride: 0.92 parts After being accommodated in a stainless steel flask and adjusted to pH 2.7, it was dispersed with a homogenizer (manufactured by IKA, Ultra Turrax T50), and then heated to 55 ° C. with stirring in an oil bath for heating. After maintaining at 55 ° C. for 2 hours, observation with an optical microscope confirmed that aggregated particles having a volume average particle diameter of about 4.7 μm were formed. After further heating and stirring at 57 ° C. for 1.5 hours, 2.5 parts of EDTA was added.

  Since the pH of the aggregated particle dispersion was measured to be 4.4, an aqueous solution obtained by diluting sodium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) to 0.5 mol / L was gently added to adjust the pH to 9.5. It was adjusted. When this aggregated particle dispersion was heated to 85 ° C. and kept for 2 hours while continuing to stir, and observed with an optical microscope, coalesced spherical particles were observed. Thereafter, the temperature was lowered to 30 ° C. at a rate of 1 ° C./min while adding ion-exchanged water to obtain particles. Then, after sufficiently washing with filtration and ion exchange water, solid-liquid separation was performed by Nutsche suction filtration. This was further redispersed in 3 L of ion exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This operation was further repeated 5 times, and solid-liquid separation was performed by Nutsche suction filtration. Next, vacuum drying was continued for 12 hours to obtain toner particles (1).

When the particle size distribution of the toner particles (1) was measured, the volume average particle size was 6.1 μm and the volume particle size distribution index GSDv was 1.24. In addition, the particle shape factor SF1 determined by shape observation with the Luzex image analyzer was 134.
Further, when chemical bonds present in the toner particles were examined by NMR C ¹³ signal, the presence of coordination bonds due to (← OO—) with respect to aluminum was detected.

-Toner particles (2)-
Toner particles (2) were obtained by the same method except that nitrilotriacetic acid was used instead of EDTA in the production of toner particles (1).

When the particle size distribution of the toner particles (2) was measured, the volume average particle size was 5.7 μm and the volume particle size distribution index GSDv was 1.23. Further, the particle shape factor SF1 obtained from the shape observation by the Luzex image analysis apparatus was 137.
Further, when chemical bonds present in the toner particles were examined by NMR C ¹³ signal, the presence of coordination bonds due to (← OO—) with respect to aluminum was detected.

-Toner particles (3)-
-Crystalline resin fine particle dispersion (2): 3000 parts-Colorant dispersion: 65 parts-Release agent dispersion: 150 parts-Polyaluminum chloride: 1.5 parts Toner particles except for using the above raw materials ( Toner particles (3) were obtained in the same manner as in 1).

When the particle size distribution of the toner particles (3) was measured, the volume average particle size was 5.9 μm and the volume particle size distribution index GSDv was 1.23. In addition, the particle shape factor SF1 obtained by shape observation with a Luzex image analyzer was 134.
Further, when chemical bonds present in the toner particles were examined by NMR C ¹³ signal, the presence of coordination bonds due to (← OO—) with respect to aluminum was detected.

-Toner particles (4)-
-Crystalline resin fine particle dispersion (1): 450 parts-Amorphous resin fine particle dispersion: 2550 parts-Release agent dispersion: 150 parts-Colorant dispersion: 67 parts-Polyaluminum chloride: 2.87 parts The above was placed in a round stainless steel flask, the pH was adjusted to 4.5, a homogenizer (IKA, Ultra Turrax T50) was dispersed, and the mixture was stirred in a heating oil bath to 60 ° C. While heating. After maintaining at 60 ° C. for 2 hours, observation with an optical microscope confirmed that aggregated particles having a volume average particle diameter of about 4.8 μm were formed. After further heating and stirring at 60 ° C. for 1 hour, 2.8 parts of nitrilotriacetic acid was added.

  At this time, the pH of the aggregated particle dispersion was measured and found to be 4.6. Therefore, an aqueous solution in which sodium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) was diluted to 0.5 mol / L was gently added to adjust the pH to 9. Adjusted to 5. When this aggregated particle dispersion was heated to 95 ° C. and kept for 30 minutes while continuing to stir, and observed with an optical microscope, coalesced spherical particles were observed. Thereafter, the temperature was lowered to 25 ° C. at a rate of 1 ° C./min while adding ion-exchanged water to obtain toner particles. Then, after sufficiently washing with filtration and ion exchange water, solid-liquid separation was performed by Nutsche suction filtration. This was further redispersed in 3 L of ion exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This operation was further repeated 5 times, and solid-liquid separation was performed by Nutsche suction filtration. Next, vacuum drying was continued for 12 hours to obtain toner particles (4).

When the particle size distribution of the toner particles (4) was measured, the volume average particle size was 5.9 μm and the volume particle size distribution index GSDv was 1.2. In addition, the particle shape factor SF1 determined by shape observation with the Luzex image analyzer was 134.
Further, when chemical bonds existing in the toner particles were examined by NMR C ¹³ signal, the presence of coordination bonds due to the (← OO—) structure with respect to aluminum was detected.

-Toner particles (5)-
Toner particles (5) were obtained by the same method except that EDTA was not added in the production of toner particles (1). When the particle size distribution of the toner particles (5) was measured, the volume average particle size D50 was 5.4 μm and the volume particle size distribution index GSDv was 1.24.

-Toner particles (6)-
Toner particles (6) were obtained in the same manner as in the production of toner particles (3) except that EDTA was not added. When the particle size distribution of the toner particles (6) was measured, the volume average particle size D50 was 5.8 μm, and the volume particle size distribution index GSDv was 1.23.

-Toner particles (7)-
Toner (7) was obtained by the same method except that EDTA was not added in the production of toner particles (4). When the particle size distribution of the toner particles (7) was measured, the volume average particle size D50 was 5.9 μm, and the volume particle size distribution index GSDv was 1.23.

-Toner particles (8)-
Amorphous resin fine particle dispersion: 3000 parts Colorant dispersion: 65 parts Release agent dispersion: 150 parts Polyaluminum chloride: 2.36 parts The above is placed in a round stainless steel flask and pH Was adjusted to 2.7, and then dispersed with a homogenizer (manufactured by IKA, Ultra Tarrax T50), and then heated to 45 ° C. with stirring in an oil bath for heating. After maintaining at 45 ° C. for 2 hours, observation with an optical microscope confirmed that aggregated particles having a volume average particle diameter of about 5.2 μm were formed. The mixture was further heated and stirred at 45 ° C. for 1.5 hours.

  Since the pH of the aggregated particle dispersion was measured to be 5.1, an aqueous solution in which sodium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) was diluted to 0.5 mol / L was gently added to adjust the pH to 9.5. It was adjusted. When this aggregated particle dispersion was heated to 85 ° C. and kept for 5 hours while continuing to stir, when observed with an optical microscope, coalesced spherical particles were observed. Thereafter, the temperature was lowered to 30 ° C. at a rate of 1 ° C./min while adding ion-exchanged water to obtain particles. Then, after sufficiently washing with filtration and ion exchange water, solid-liquid separation was performed by Nutsche suction filtration. This was further redispersed in 3 L of ion exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This operation was further repeated 5 times, and solid-liquid separation was performed by Nutsche suction filtration. Next, vacuum drying was continued for 12 hours to obtain toner particles (8).

  When the particle size distribution of the toner particles (8) was measured, the volume average particle size was 6.4 μm and the volume particle size distribution index GSDv was 1.26. In addition, the particle shape factor SF1 obtained from the shape observation by the Luzex image analyzer was 136.

-Toner particles (9)-
In the production of toner particles (8), toner particles (9) were obtained in the same manner except that 2.5 parts of EDTA was added at 45 ° C., which is an aggregation step.

When the particle size distribution of the toner particles (9) was measured, the volume average particle size was 6.1 μm and the volume particle size distribution index GSDv was 1.21. In addition, the particle shape factor SF1 obtained from the shape observation by the Luzex image analyzer was 135.
Further, when chemical bonds present in the toner particles were examined by NMR C ¹³ signal, the presence of coordination bonds due to (← OO—) with respect to aluminum was detected.

-Toner particles (10)-
Toner particles (10) were obtained by the same method except that magnesium chloride hexahydrate was used instead of EDTA in the production of toner particles (1).

<Preparation of toner and developer>
To 100 parts of the toner particles (1) to (10) prepared above, 1.2 parts of fine titania powder (manufactured by Taika Co., Ltd.) treated with decyltrimethoxysilane each having a volume average particle size of 30 nm is added and stirred and mixed. Blended in a machine to make toners 1-10. Each of these was weighed so that the toner concentration was 5% with respect to a ferrite carrier having a volume average particle diameter of 35 μm coated with 1% of polymethacrylate (manufactured by Soken Chemical Co., Ltd., Mw: 75000), and a ball mill for 5 minutes. Developers (1) to (10) were prepared by stirring and mixing.

  For the toners (1) to (10) produced above, the volume resistivity and dielectric loss factor were measured by the methods described above. The results are shown in Table 1 together with the evaluation results of the following examples and comparative examples.

<Example 1>
A color copier DocuCentreColor 500 (manufactured by Fuji Xerox Co., Ltd.) was prepared, and modified so that both a DC component and an AC component could be applied as a developing bias of the developing device. Specifically, −520 V was applied as a direct current bias and Vpp 1.5 kV was applied independently as an alternating current bias.

Using the modified machine as an image forming apparatus, the developer (1) is loaded, and the toner loading is adjusted to 15.0 g / m ² under the development condition in which the DC bias and the AC bias are superimposed. The following evaluations were made.

(Fixability evaluation)
The fixing device was removed from the image forming apparatus, and an unfixed image was collected. The image condition was a solid image of 25 mm × 25 mm, the applied toner amount was 15.0 g / m ² , and J paper manufactured by Fuji Xerox Co. was used as the recording paper.
Next, the fixing unit of the DocuCentreColor 500 was modified so that the fixing temperature was variable, and the fixing property of the unfixed image was evaluated while the fixing temperature was increased stepwise from 90 ° C. to 220 ° C.

  Note that the fixability is practical, although there is no image loss due to defective release, a good fixed image is bent using a weight of a certain load, and the degree of image loss at that part is observed, and some image peeling is observed. The fixing temperature at which the level at which it is determined that there is no problem above is the minimum fixing temperature, and is used as an index for low-temperature fixing property.

(Image quality evaluation)
Using the above-mentioned DocuCentreColor500 remodeling machine, after performing continuous printing of 2000 sheets under the development condition in which DC bias and AC bias are superimposed in the same manner, the evaluation of the fixed image is performed in terms of the presence of white spots, image density, and fog. It carried out from.
-Image density-
For the evaluation of the image density, an image densitometer X-rite 404 (manufactured by X-rite) was used, and the determination was made according to the following evaluation criteria.
○: The concentration measurement value is 1.2 or more, and there is no practical problem.
(Triangle | delta): A density | concentration measured value is 1-1.2, and is accept | permitted practically.
X: The measured density value is less than 1, which is not acceptable in practice.

-Cover-
The image after fixing was evaluated visually according to the following criteria.
○: There is no visual fogging and there is no practical problem. Δ: Some fogging is visually observed, but practically acceptable. X: Visual fogging is remarkable and practically unacceptable Table 1 summarizes the above results. Shown in

<Examples 2 to 4>
In Example 1, the evaluation was performed in the same manner except that the developers (2) to (4) were used instead of the developer (1).
The results are shown in Table 1.

<Example 5>
Evaluation was performed in the same manner as in Example 1 except that the developer (10) was used instead of the developer (1).
The results are shown in Table 1.

<Example 6>
In Example 1, evaluation was performed in the same manner except that the developer (7) was used instead of the developer (1).
The results are shown in Table 1.

<Comparative Example 1>
In Example 1, the evaluation was performed in the same manner except that the developer (5) was used instead of the developer (1).
The results are shown in Table 1.

<Comparative example 2>
Evaluation was conducted in the same manner as in Comparative Example 1 except that the development conditions were such that only a DC bias was applied.
The results are shown in Table 1.

<Comparative Examples 3-5>
In Example 1, evaluation was performed in the same manner except that the developers (6), (8), and (9) were used instead of the developer (1).
The results are shown in Table 1.

  As shown in Table 1, in Examples 1 to 7, the chelating agent or metal salt is added in the aggregation process, so that the conduction path of the crystalline resin in the toner is interrupted, and the alternating current is generated in the development process. Even if an electric field is used, a phenomenon such as charge injection does not occur, and both low-temperature fixability and high development / transfer properties are possible. In Example 4, since the crystalline resin and the amorphous resin are used in combination as the binder resin, although the fixing temperature is slightly increased, the most excellent result in developing / transferability is obtained. Yes.

  On the other hand, in Comparative Examples 1 and 3, since the conduction path is not blocked by the addition of a chelating agent or a metal salt, toner charge injection is significant and image defects occur. In contrast, Comparative Example 2 uses only a DC electric field in the developing process, and it can be seen that defects such as image defects are improved as compared with Comparative Example 1 using an AC electric field. That is, when the conduction path is not interrupted, it is considered that the deterioration of the electrical characteristics of the toner is reduced under the direct current electric field than under the alternating current electric field. Further, when the toner binder resin is an amorphous resin alone as in Comparative Example 4 and Comparative Example 5, high development and transfer efficiency can be obtained regardless of the use or non-use of a chelating agent, so that defects such as image defects can be obtained. However, since the crystalline resin is not used, the fixing temperature is high.

Claims (4)

An electrostatic image developing toner comprising a crystalline resin as a binder resin component,
The toner contains a structure represented by the following formula (1), the volume resistivity at an applied voltage of 1000 V is 3.0 × 10 ¹³ Ωcm or more, and / or the dielectric loss factor at a frequency of 1000 Hz is 0.001 to 0.001. An electrostatic charge image developing toner having a range of 0.035.
M (← OOC-R) n Formula (1)
(In the above formula (1), M is a divalent or higher valent metal, ← is a coordination bond, R is a functional group having one of aliphatic, alicyclic and aromatic structures having 1 or more carbon atoms. , N represents an integer of 2 to 7, respectively. An agglomeration step of mixing at least a resin fine particle dispersion in which crystalline resin fine particles are dispersed and a colorant dispersion in which colorant particles are dispersed and raising the temperature to form aggregated particles of the resin fine particles and the colorant particles; A method for producing a toner for developing an electrostatic charge image, comprising: a step of heating an aggregated particle dispersion in which particles are dispersed to a temperature equal to or higher than a melting point of the resin fine particles to fuse and coalesce the aggregated particles,
A method for producing a toner for developing an electrostatic charge, wherein a divalent or higher metal salt and / or a chelating agent is further mixed in the temperature raising step of the aggregation step. A latent image forming step of forming an electrostatic latent image on the surface of the latent image carrier, and an electrostatic latent image formed on the surface of the latent image carrier using a developer containing toner carried on the developer carrier. A developing step for developing a toner image, a transfer step for transferring the toner image formed on the latent image carrying surface to the surface of the transfer target, and a fixing for thermally fixing the toner image transferred to the surface of the transfer target An image forming method comprising at least a step,
An image forming method using the toner for developing an electrostatic charge image according to claim 1 as the toner.   The image forming method according to claim 3, wherein the developer carrying member is developed by applying a voltage including an AC component as a developing bias.