JP2017032598A - Toner for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development containing toner base particles obtained by introducing a crystalline resin to a styrene-acrylic resin, and an external additive, the toner capable of being fixed at a low temperature and stably outputting high-quality images irrespective of a printing environment and the state of use.SOLUTION: There is provided a toner for electrostatic charge image development containing toner base particles including a styrene-acrylic resin and a crystalline resin as a binder resin, and an external additive, where the external additive contains titanium oxide having an average aspect ratio in a range of 2 to 15, which is derived from a ratio of the number average major axis to the number average minor axis, and spherical silica having a number average particle diameter larger than the number average minor axis of the titanium oxide and a range of the number average particle diameter of 60 to 150 nm.SELECTED DRAWING: None

Description

  The present invention relates to a toner for developing an electrostatic image.

  In recent years, with the spread of digital printing, it is increasingly desired to improve the quality of output images. In order to form a fine and high-quality image, it is necessary that the particle size distribution of the toner is sharp, and the development behavior of each individual toner particle is uniformed, thereby improving the fine dot reproducibility. Here, by including a styrene acrylic resin in the resin constituting the toner, a toner manufacturing method suitable for narrow particle size distribution such as an emulsion aggregation method can be applied (see, for example, Patent Document 1).

  On the other hand, for the purpose of increasing the printing speed and reducing the environmental load, the heat energy required for fixing the toner image is reduced to save energy. In order to realize low-temperature fixing of the toner, there is a method of introducing a crystalline resin excellent in sharp melt property into the binder resin (for example, see Patent Document 2). This makes it possible to rapidly lower the melt viscosity at a temperature higher than the melting point.

  For these reasons, a toner in which a crystalline resin is introduced into a styrene acrylic resin to enable high-quality image formation and has improved low-temperature fixability has been studied (for example, see Patent Document 3).

JP 2012-27059 A JP 2005-338548 A JP 2011-197659 A

  However, since the affinity between the styrene acrylic resin and the crystalline resin is poor and the crystalline resin is difficult to be taken into the styrene acrylic resin, the surface composition of the toner base particles becomes non-uniform. As a result, the toner base particles cannot have a sufficient charge amount, and a tendency of a decrease in the charge amount appears particularly under high temperature and high humidity.

  Further, in order to ensure low-temperature fixability, it is necessary to design the toner base particles softly. In such a case, when an external additive is added to the surface of the toner base particles, the external additive to the toner base particles Buried easily occurs. As a result, a decrease in charge amount due to toner deterioration under high stress, such as a low-coverage large-volume print, and a corresponding decrease in image quality of the output image occur.

  Accordingly, the present invention provides a toner for developing electrostatic images containing toner base particles obtained by introducing a crystalline resin into a styrene acrylic resin and an external additive, which can be fixed at low temperature, but is stable regardless of the printing environment and usage conditions. Another object is to provide a toner capable of outputting an image with high image quality.

  As a result of diligent studies to solve the above-described problems and achieve the above-mentioned object, the present inventors have found that toner base particles containing a styrene acrylic resin and a crystalline resin, which are binder resins, and an external additive. In the toner for developing a charge image, the present inventors have found that the above problems can be solved by using titanium oxide having a predetermined average aspect ratio and spherical silica having a predetermined number average particle diameter as external additives. Completed the invention.

  That is, the said subject which concerns on this invention is solved by the following means.

1. An electrostatic charge image developing toner comprising toner base particles containing a styrene acrylic resin and a crystalline resin as a binder resin, and an external additive,
The external additive includes titanium oxide having an average aspect ratio in the range of 2 to 15 derived from the ratio of the number average major axis to the number average minor axis, and a number average particle size larger than the number average minor axis of the titanium oxide. And a toner for developing an electrostatic charge image, comprising spherical silica having a range of 60 to 150 nm.

  2. 1. The crystalline resin is a crystalline polyester resin. The toner for developing an electrostatic charge image according to 1.

  3. The crystalline polyester resin is a hybrid crystalline polyester resin containing an amorphous resin other than the crystalline polyester resin as a unit. Or 2. The toner for developing an electrostatic charge image according to 1.

  4). The content of the crystalline resin in the toner base particles is 1 to 30% by mass. ~ 3. The toner for developing an electrostatic image according to any one of the above.

  5. The titanium oxide has a rutile-type crystal structure; ~ 4. The toner for developing an electrostatic image according to any one of the above.

  6). 1 above. ~ 5. A two-component developer for developing an electrostatic charge image, comprising the toner for developing an electrostatic charge image according to any one of the above and carrier particles.

  According to the present invention, there is provided a toner for developing an electrostatic charge image capable of stably outputting a high-quality image even in a printing environment under a high temperature and high humidity or for a long period of use while being capable of fixing at a low temperature. The

One embodiment of the present invention is an electrostatic charge image developing toner comprising toner base particles containing a styrene acrylic resin and a crystalline resin as a binder resin, and an external additive,
The external additive includes titanium oxide having an average aspect ratio in the range of 2 to 15 derived from the ratio of the number average major axis to the number average minor axis, and a number average particle size larger than the number average minor axis of the titanium oxide. And a toner for developing an electrostatic charge image, comprising spherical silica having a range of 60 to 150 nm.

  As described above, in developing a low-temperature fixable toner capable of high-quality image output and high-speed printing, and realizing low environmental impact, a crystalline resin excellent in sharp melt property and an amorphous resin as a binder resin The use of and is being considered. By using a styrene acrylic resin that has a sharp particle size distribution of the obtained toner and can impart a sufficient charge amount as the amorphous resin, the sharp melt property is improved.

  However, there is a problem in that the surface composition of the toner base particles becomes non-uniform because the affinity between the crystalline resin and the styrene acrylic resin is poor, and the crystalline resin is difficult to be taken into the styrene acrylic resin. It was. If a crystalline resin having low resistance is present in the vicinity of the surface of the toner base particles, the toner cannot have a sufficient charge amount, and a tendency to decrease the charge amount is particularly strong under high temperature and high humidity. A decrease in the toner charge amount causes image defects such as a decrease in image density and fogging.

  In the present invention, the environmental stability of the toner charge amount is improved by externally adding titanium oxide. At this time, the use of titanium oxide having an average aspect ratio in the range of 2 to 15 increases the contact area between the titanium oxide and the toner base particles. Therefore, the movement of the titanium oxide particles on the surface of the toner base particles is difficult to occur. Thereby, it is possible to prevent aggregation of external additives on the irregularities on the surface of the toner base particles, which can occur when the toner is subjected to high stress. In addition, since the uniform coating state of titanium oxide is maintained for a long time, the environmental stability of the toner charge amount can be maintained.

  Further, in the toner of the present invention, spherical silica having a relatively large diameter, such as a number average particle diameter larger than that of the titanium oxide and a number average particle diameter of 60 to 150 nm, is externally added. Such spherical silica exhibits a high spacer effect, and can suppress the burying and movement of not only the spherical silica itself but also other external additives such as titanium oxide.

  The spacer effect of the spherical silica also prevents the crystalline resin existing near the surface of the toner base particles from coming into contact with the carrier particles when the toner is used as a two-component developer together with the carrier particles. Have. Thereby, charging leakage of the toner through the low-resistance crystalline resin can be suppressed, and the effect of ensuring the toner charge amount can be enhanced regardless of the printing environment and printing conditions. As a result, the initial external addition state of the toner can be maintained over a long period of time and even in a high temperature and high humidity environment.

  As described above, the toner of the present invention can output a high image quality and can be fixed at a low temperature with a narrow particle size distribution, and can stably output an image regardless of the printing environment and usage conditions.

  Embodiments of the present invention will be described below. In addition, this invention is not limited only to the following embodiment. In this specification, “X to Y” indicating a range means “X or more and Y or less”. Unless otherwise specified, measurement of operation and physical properties is performed under conditions of room temperature (25 ° C.) / Relative humidity 40 to 50%.

[Binder resin]
The binder resin constituting the toner according to the present invention includes a crystalline resin and a styrene acrylic resin.

<Crystalline resin>
The crystalline resin in the present invention indicates a resin having a clear endothermic peak, not a stepwise endothermic change in differential scanning calorimetry (DSC). Specifically, the endothermic peak means a peak in which the half-value width of the endothermic peak is within 15 ° C., for example, in differential scanning calorimetry (DSC) when measured at a heating rate of 10 ° C./min. To do. Examples of the crystalline resin include a crystalline polyester resin and a crystalline vinyl resin. Although not particularly limited, a crystalline polyester resin is preferable for realizing low-temperature fixability. As the crystalline polyester resin, a known polyester resin obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a divalent or higher alcohol (polyhydric alcohol) can be used.

  Further, the crystalline polyester resin is more preferably a hybrid crystalline polyester resin containing an amorphous resin other than the crystalline polyester resin as a unit. The amorphous resin unit is preferably made of the same type of resin as the amorphous resin contained in the binder resin, that is, a resin other than the hybrid resin. By hybridizing in such a form, the affinity between the crystalline polyester resin and the amorphous resin is increased, and the hybrid resin is more easily taken into the amorphous resin. As a result, the surface composition of the toner base particles becomes more uniform, and the charging uniformity is further improved. Also, environmental stability can be improved.

  Hereinafter, the crystalline polyester resin and the hybrid crystalline polyester resin will be described.

(Hybrid crystalline polyester resin (hybrid resin))
The hybrid crystalline polyester resin (hybrid resin) is a resin in which a crystalline polyester resin unit and an amorphous resin unit other than the polyester resin are chemically bonded.

  In the above, the crystalline polyester resin unit refers to a portion derived from the crystalline polyester resin. That is, it refers to a molecular chain having the same chemical structure as that constituting the crystalline polyester resin. Moreover, the amorphous resin unit other than the polyester resin refers to a portion derived from an amorphous resin other than the polyester. That is, it refers to a molecular chain having the same chemical structure as that constituting an amorphous resin other than a polyester resin.

≪Crystalline polyester resin unit≫
The crystalline polyester resin unit is a portion derived from a known polyester resin obtained by a polycondensation reaction of a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a divalent or higher alcohol (polyhydric alcohol). In differential scanning calorimetry (DSC), it refers to a resin unit having a clear endothermic peak rather than a stepwise endothermic change. Specifically, the clear endothermic peak means that the half-value width of the endothermic peak is within 15 ° C. when measured at a heating rate of 10 ° C./min in the differential scanning calorimetry (DSC) described in the examples. It means a peak.

  The crystalline polyester resin unit is not particularly limited as long as it is defined above. For example, this resin is used for a resin having a structure in which other components are copolymerized on the main chain of a crystalline polyester resin unit, or a resin having a structure in which a crystalline polyester resin unit is copolymerized on a main chain composed of other components. If the toner to be contained exhibits a clear endothermic peak as described above, the resin corresponds to a hybrid resin having a crystalline polyester resin unit in the present invention.

  The crystalline polyester resin unit is generated from a polyvalent carboxylic acid component and a polyhydric alcohol component.

  In addition, the valences of the polyvalent carboxylic acid component and the polyhydric alcohol component are each preferably 2 to 3 and particularly preferably 2 respectively. Therefore, when the valence is 2 respectively as a particularly preferable form (that is, , Dicarboxylic acid component, diol component).

  As the dicarboxylic acid component, an aliphatic dicarboxylic acid is preferably used, and an aromatic dicarboxylic acid may be used in combination. As the aliphatic dicarboxylic acid, it is preferable to use a linear one. By using a linear type, there is an advantage that crystallinity is improved. The dicarboxylic acid component is not limited to one type, and two or more types may be mixed and used.

  Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. Acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid (dodecanedioic acid), 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1, Examples thereof include 18-octadecanedicarboxylic acid, and these lower alkyl esters and acid anhydrides can also be used.

  Among the above aliphatic dicarboxylic acids, aliphatic dicarboxylic acids having 6 to 12 carbon atoms are preferable because the effects of the present invention are easily obtained.

  Examples of the aromatic dicarboxylic acid that can be used together with the aliphatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, t-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid. Is mentioned. Among these, terephthalic acid, isophthalic acid, and t-butylisophthalic acid are preferably used from the viewpoints of availability and emulsification ease.

  As the dicarboxylic acid component for forming the crystalline polyester resin unit, the aliphatic dicarboxylic acid content is preferably 50 constituent mol% or more, more preferably 70 constituent mol% or more, and still more preferably. It is 80 constituent mol% or more, Most preferably, it is 100 constituent mol%. When the content of the aliphatic dicarboxylic acid in the dicarboxylic acid component is 50 constituent mol% or more, the crystallinity of the crystalline polyester resin unit can be sufficiently ensured.

  Moreover, it is preferable to use aliphatic diol as a diol component, and you may contain diols other than aliphatic diol as needed. As the aliphatic diol, a linear diol is preferably used. By using a linear type, there is an advantage that crystallinity is improved. A diol component may be used individually by 1 type, and may be used 2 or more types.

  Examples of the aliphatic diol 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-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18- Examples include octadecanediol and 1,20-eicosanediol.

  Among the aliphatic diols, the diol component is preferably an aliphatic diol having 2 to 12 carbon atoms, more preferably an aliphatic diol having 6 to 12 carbon atoms, because the effects of the present invention can be easily obtained.

  Examples of the diol other than the aliphatic diol used as necessary include a diol having a double bond and a diol having a sulfonic acid group. Specifically, examples of the diol having a double bond include 2 -Butene-1,4-diol, 3-butene-1,6-diol, 4-butene-1,8-diol and the like.

  As the diol component for forming the crystalline polyester resin unit, the content of the aliphatic diol is preferably 50 component mol% or more, more preferably 70 component mol% or more, and still more preferably 80 component mol%. It is at least mol%, particularly preferably 100 constituent mol%. When the content of the aliphatic diol in the diol component is 50 constituent mol% or more, the crystallinity of the crystalline polyester resin unit can be ensured, and excellent low-temperature fixability is obtained in the manufactured toner. Glossiness is obtained in the finally formed image.

  The use ratio of the diol component to the dicarboxylic acid component is such that the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] of the diol component to the carboxyl group [COOH] of the dicarboxylic acid component is 1.5 / 1. It is preferable to be set to ˜1 / 1.5, and more preferably 1.2 / 1 to 1 / 1.2.

  The method for forming the crystalline polyester resin unit is not particularly limited, and the unit is formed by polycondensation (esterification) of the polyvalent carboxylic acid and the polyhydric alcohol using a known esterification catalyst. Can do.

  Catalysts that can be used in the production of the crystalline polyester resin unit include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; aluminum, zinc, manganese, antimony, titanium, tin, and zirconium And metal compounds such as germanium; phosphorous acid compounds; phosphoric acid compounds; and amine compounds. Specifically, examples of the tin compound include dibutyltin oxide, tin octylate, tin dioctylate, and salts thereof. Titanium compounds include titanium alkoxides such as tetranormal butyl titanate, tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate; titanium acylates such as polyhydroxy titanium stearate; titanium tetraacetylacetonate, titanium lactate, titanium triethanolamine Examples thereof include titanium chelates such as nates. Examples of germanium compounds include germanium dioxide. Furthermore, examples of the aluminum compound include oxides such as polyaluminum hydroxide, aluminum alkoxide, and the like, and tributylaluminate and the like can be given. You may use these individually by 1 type or in combination of 2 or more types.

  The polymerization temperature is not particularly limited, but is preferably 150 to 250 ° C. The polymerization time is not particularly limited, but is preferably 0.5 to 10 hours. During the polymerization, the pressure in the reaction system may be reduced as necessary.

  The content of the crystalline polyester resin unit is preferably 80% by mass or more and 98% by mass or less with respect to the total amount of the hybrid resin. Furthermore, the content is more preferably 90% by mass or more and 95% by mass or less, and further preferably 91% by mass or more and 93% by mass or less. By setting it as the above range, sufficient crystallinity can be imparted to the hybrid resin. In addition, the structural component and content rate of each unit in a hybrid resin can be specified, for example by NMR measurement and methylation reaction P-GC / MS measurement.

  Here, the hybrid resin includes an amorphous resin unit other than the polyester resin described in detail below in addition to the crystalline polyester resin unit. The hybrid resin may be in any form such as a block copolymer and a graft copolymer as long as it includes the crystalline polyester resin unit and an amorphous resin unit other than the polyester resin. A coalescence is preferable. By using a graft copolymer, the orientation of the crystalline polyester resin unit can be easily controlled, and sufficient crystallinity can be imparted to the hybrid resin.

  Furthermore, from the above viewpoint, it is preferable that the crystalline polyester resin unit is grafted with an amorphous resin unit other than the crystalline polyester resin as a main chain. That is, the hybrid crystalline polyester resin is preferably a graft copolymer having an amorphous resin unit other than the polyester resin as a main chain and a crystalline polyester resin unit as a side chain.

  By setting it as the said form, the orientation of a crystalline polyester resin unit can be raised more, and the crystallinity of hybrid resin can be improved.

  In addition, substituents, such as a sulfonic acid group, a carboxyl group, and a urethane group, may be further introduced into the hybrid resin. The introduction of the substituent may be in the crystalline polyester resin unit or in an amorphous resin unit other than the polyester resin described in detail below.

≪Amorphous resin unit other than polyester resin≫
Amorphous resin units other than polyester resins (sometimes referred to simply as “amorphous resin units” in this specification) control the affinity between the amorphous resin and the hybrid resin constituting the binder resin. It is an indispensable unit. The presence of the amorphous resin unit improves the affinity between the hybrid resin and the amorphous resin, makes it easier for the hybrid resin to be incorporated into the amorphous resin, and improves charging uniformity and the like. .

  The amorphous resin unit is a portion derived from an amorphous resin other than the crystalline polyester resin. The inclusion of an amorphous resin unit in the hybrid resin (and also in the toner) can be confirmed by specifying the chemical structure using, for example, NMR measurement or methylation reaction P-GC / MS measurement. .

  The amorphous resin unit does not have a melting point and has a relatively high glass transition temperature (Tg) when differential scanning calorimetry (DSC) is performed on a resin having the same chemical structure and molecular weight as the unit. It is a resin unit. At this time, for a resin having the same chemical structure and molecular weight as the unit, the glass transition temperature (Tg1) in the first temperature rising process in DSC measurement is preferably 30 to 80 ° C., particularly 40 to 65 ° C. Preferably there is. The glass transition temperature can be obtained by DSC measurement described in the examples, and the onset temperature in the first temperature raising process is Tg1.

  The amorphous resin unit is not particularly limited as long as it is defined above. For example, for a resin having a structure in which other components are copolymerized on the main chain of an amorphous resin unit and a resin having a structure in which an amorphous resin unit is copolymerized on a main chain composed of other components, this resin is used. If the toner to be contained has an amorphous resin unit as described above, the resin corresponds to the hybrid resin having an amorphous resin unit in the present invention.

  The amorphous resin unit is preferably composed of the same kind of resin as the amorphous resin (that is, a resin other than the hybrid resin) contained in the binder resin. By adopting such a form, the affinity between the hybrid resin and the amorphous resin is further improved, the hybrid resin is further easily taken into the amorphous resin, and the charging uniformity is further improved.

  Here, “the same kind of resin” means that a characteristic chemical bond is commonly contained in the repeating unit. Here, “characteristic chemical bond” is described in the National Institute for Materials Science (NIMS) Substance / Material Database (http://polymer.nims.go.jp/PoLyInfo/guide/jp/term_polymer.html). According to “Polymer classification”. That is, polyacryl, polyamide, polyanhydride, polycarbonate, polydiene, polyester, polyhaloolefin, polyimide, polyimine, polyketone, polyolefin, polyether, polyphenylene, polyphosphazene, polysiloxane, polystyrene, polysulfide, polysulfone, polyurethane, polyurea Chemical bonds constituting polymers classified by a total of 22 types of polyvinyl and other polymers are referred to as “characteristic chemical bonds”.

  In addition, the “same kind of resin” in the case where the resin is a copolymer is characteristic when the monomer type having the above chemical bond is used as a constituent unit in the chemical structure of a plurality of monomer types constituting the copolymer. Refers to resins having common chemical bonds. Accordingly, even if the characteristics of the resins themselves are different from each other or the molar component ratios of the monomer species constituting the copolymer are different from each other, the same type of resin can be used as long as it has a characteristic chemical bond in common. It is considered.

  For example, a resin (or resin unit) formed of styrene, butyl acrylate and acrylic acid and a resin (or resin unit) formed of styrene, butyl acrylate and methacrylic acid have at least chemical bonds constituting polyacryl. These are the same kind of resins. To further illustrate, a resin (or resin unit) formed of styrene, butyl acrylate and acrylic acid and a resin (or resin unit) formed of styrene, butyl acrylate, acrylic acid, terephthalic acid and fumaric acid are mutually As a common chemical bond, it has a chemical bond constituting at least polyacryl. Therefore, these are the same kind of resins.

  Although the resin component which comprises an amorphous resin unit is not restrict | limited in particular, For example, a vinyl resin unit, a urethane resin unit, a urea resin unit etc. are mentioned. Among these, a vinyl resin unit is preferable because it is easy to control thermoplasticity.

  The vinyl resin unit is not particularly limited as long as a vinyl compound is polymerized, and examples thereof include an acrylic ester resin unit, a styrene-acrylic ester resin unit, and an ethylene / vinyl acetate resin unit. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Among the vinyl resin units described above, a styrene-acrylic ester resin unit (styrene acrylic resin unit) is preferable in consideration of plasticity during heat fixing. Therefore, below, the styrene acrylic resin unit as an amorphous resin unit is demonstrated.

The styrene acrylic resin unit is formed by addition polymerization of at least a styrene monomer and a (meth) acrylic acid ester monomer. Styrene monomers as referred to herein, in addition to styrene represented by the structural formula _{CH 2 = CH-C 6 H} 5, is intended to include a structure having a known side-chain or functional groups styrene structure. In addition, the (meth) acrylic acid ester monomer referred to here is an acrylic acid ester derivative or methacrylic acid in addition to the acrylic acid ester compound or methacrylic acid ester compound represented by CH ₂ = CHCOOR (R is an alkyl group). It includes an ester compound having a known side chain or functional group in the structure of an ester derivative or the like.

  Specific examples of styrene monomer and (meth) acrylic acid ester monomer capable of forming a styrene acrylic resin unit are shown below, but can be used for forming a styrene acrylic resin unit used in the present invention. Is not limited to the following.

  First, specific examples of the styrene monomer include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4- Examples thereof include dimethyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, and pn-dodecyl styrene. These styrene monomers can be used alone or in combination of two or more.

  Specific examples of the (meth) acrylic acid ester monomer include, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate. Acrylate monomers such as stearyl acrylate, lauryl acrylate, and phenyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, Stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl meta Relate, methacrylic acid ester monomers such as dimethylaminoethyl methacrylate.

  In this specification, “(meth) acrylic acid ester monomer” is a general term for “acrylic acid ester monomer” and “methacrylic acid ester monomer”. “Methyl acrylate” is a general term for “methyl acrylate” and “methyl methacrylate”.

  These acrylic acid ester monomers or methacrylic acid ester monomers can be used alone or in combination of two or more. That is, a copolymer is formed using a styrene monomer and two or more acrylate monomers, and a copolymer is formed using a styrene monomer and two or more methacrylic ester monomers. Either a coalescence can be formed, or a copolymer can be formed by using a styrene monomer together with an acrylate monomer and a methacrylic acid ester monomer.

  The content of the structural unit derived from the styrene monomer in the amorphous resin unit is preferably 40 to 90% by mass with respect to the total amount of the amorphous resin unit. Moreover, it is preferable that the content rate of the structural unit derived from the (meth) acrylic acid ester monomer in an amorphous resin unit is 10-60 mass% with respect to the whole quantity of an amorphous resin unit. By setting it as such a range, it becomes easy to control the plasticity of the hybrid resin.

  Further, the amorphous resin unit is preferably obtained by addition polymerization of a compound for chemically bonding to the crystalline polyester resin unit in addition to the styrene monomer and the (meth) acrylate monomer. . Specifically, it is preferable to use a compound that includes an ester bond with a hydroxyl group derived from a polyhydric alcohol [—OH] or a carboxyl group derived from a polyvalent carboxylic acid [—COOH] contained in the crystalline polyester resin unit. Therefore, the amorphous resin unit can be addition-polymerized with respect to the styrene monomer and the (meth) acrylate monomer, and has a carboxyl group [—COOH] or a hydroxyl group [—OH]. It is preferable to further polymerize the compound.

  Examples of such compounds include compounds having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester; 2-hydroxy Ethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate And compounds having a hydroxyl group such as polyethylene glycol mono (meth) acrylate.

  The content rate of the structural unit derived from the said compound in an amorphous resin unit is preferable in it being 0.5-20 mass% with respect to the whole quantity of an amorphous resin unit.

  The method for forming the styrene acrylic resin unit is not particularly limited, and examples thereof include a method of polymerizing a monomer using a known oil-soluble or water-soluble polymerization initiator. Specific examples of the oil-soluble polymerization initiator include the following azo or diazo polymerization initiators and peroxide polymerization initiators.

  As the azo or diazo polymerization initiator, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1) -Carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and the like.

  As the peroxide polymerization initiator, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4 -Dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4-t-butylperoxycyclohexyl) propane, tris- (t-butylperoxy) triazine and the like.

  In the case where resin fine particles (resin particles) are formed by an emulsion polymerization method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide, and the like.

  The content of the amorphous resin unit is preferably 2% by mass or more and 20% by mass or less with respect to the total amount of the hybrid resin. Furthermore, the content is more preferably 5% by mass or more and 10% by mass or less, and further preferably 7% by mass or more and 9% by mass or less. By setting it as the above range, sufficient crystallinity can be imparted to the hybrid resin.

≪Method for producing hybrid crystalline polyester resin (hybrid resin) ≫
The method for producing the hybrid resin contained in the binder resin is not particularly limited as long as it can form a polymer having a structure in which the crystalline polyester resin unit and the amorphous resin unit are molecularly bonded. It is not something. Specific examples of the method for producing the hybrid resin include the following methods.

(1) A method of producing a hybrid resin by polymerizing an amorphous resin unit in advance and performing a polymerization reaction to form a crystalline polyester resin unit in the presence of the amorphous resin unit. An amorphous resin unit is formed by addition reaction of the monomer constituting the above-described amorphous resin unit (preferably, a styrene monomer and a vinyl monomer such as a (meth) acrylate monomer). . Next, in the presence of the amorphous resin unit, a polyvalent carboxylic acid and a polyhydric alcohol are polymerized to form a crystalline polyester resin unit. At this time, a polyhydric carboxylic acid and a polyhydric alcohol are subjected to a condensation reaction, and a polycarboxylic acid or a polyhydric alcohol is added to the amorphous resin unit to form a hybrid resin.

  In the above method, it is preferable to incorporate a site where these units can react with each other in the crystalline polyester resin unit or the amorphous resin unit. Specifically, when the amorphous resin unit is formed, in addition to the monomer constituting the amorphous resin unit, a carboxyl group [—COOH] or a hydroxyl group [—OH] remaining in the crystalline polyester resin unit. A compound having a site capable of reacting with a non-crystalline resin unit and a site capable of reacting with an amorphous resin unit is also used. That is, when this compound reacts with a carboxyl group [—COOH] or a hydroxyl group [—OH] in the crystalline polyester resin unit, the crystalline polyester resin unit can be chemically bonded to the amorphous resin unit. it can.

  Alternatively, a compound having a site capable of reacting with a polyhydric alcohol or polyvalent carboxylic acid and capable of reacting with an amorphous resin unit may be used when forming the crystalline polyester resin unit.

  By using the above method, a hybrid resin having a structure (graft structure) in which a crystalline polyester resin unit is molecularly bonded to an amorphous resin unit can be formed.

(2) A method of producing a hybrid resin by forming a crystalline polyester resin unit and an amorphous resin unit and bonding them together. In this method, first, a polyvalent carboxylic acid and a polyhydric alcohol are condensed. React to form a crystalline polyester resin unit. In addition to the reaction system for forming the crystalline polyester resin unit, the monomer constituting the above-described amorphous resin unit is subjected to addition polymerization to form the amorphous resin unit. At this time, it is preferable to incorporate a site where the crystalline polyester resin unit and the amorphous resin unit can react with each other. In addition, since the method of incorporating such a reactive site is as described above, detailed description thereof is omitted.

  Next, a hybrid resin having a structure in which the crystalline polyester resin unit and the amorphous resin unit are molecularly bonded can be formed by reacting the crystalline polyester unit formed above with the amorphous resin unit. it can.

  In addition, when the reactive site is not incorporated in the crystalline polyester resin unit and the amorphous resin unit, a system in which the crystalline polyester resin unit and the amorphous resin unit coexist is formed, You may employ | adopt the method of throwing in the compound which has a site | part which can be combined with a crystalline polyester resin unit and an amorphous resin unit. A hybrid resin having a structure in which a crystalline polyester resin unit and an amorphous resin unit are molecularly bonded can be formed via the compound.

(3) A method of producing a hybrid resin by forming a crystalline polyester resin unit in advance and performing a polymerization reaction to form an amorphous resin unit in the presence of the crystalline polyester resin unit. A polyvalent carboxylic acid and a polyhydric alcohol are subjected to a condensation reaction to carry out polymerization to form a crystalline polyester resin unit. Next, in the presence of the crystalline polyester resin unit, a monomer constituting the amorphous resin unit is polymerized to form an amorphous resin unit. At this time, it is preferable to incorporate a site where these units can react with each other in the crystalline polyester resin unit or the amorphous resin unit, similarly to the above (1). In addition, since the method of incorporating such a reactive site is as described above, detailed description thereof is omitted.

  By using the above method, a hybrid resin having a structure (graft structure) in which an amorphous resin unit is molecularly bonded to a crystalline polyester resin unit can be formed.

  Among the methods (1) to (3), the method (1) facilitates the formation of a hybrid resin having a structure in which a crystalline polyester resin chain is grafted to an amorphous resin chain, and simplifies the production process. This is preferable because it is possible. In the method (1), since the amorphous polyester resin unit is bonded after the amorphous resin unit is formed in advance, the orientation of the crystalline polyester resin unit tends to be uniform. Therefore, it is preferable because a hybrid resin suitable for the toner specified in the present invention can be reliably formed.

(Crystalline polyester resin)
The crystalline polyester resin is not particularly limited, and is a known polyester resin obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a divalent or higher alcohol (polyhydric alcohol). Can be widely applied. Here, the crystalline polyester resin refers to a resin having a clear endothermic peak instead of a stepwise endothermic change in differential scanning calorimetry (DSC) among the above-described polyester resins. Specifically, the endothermic peak has a half-value width of 15 ° C. or less when measured at a rate of temperature increase of 10 ° C./min in the differential scanning calorimetry (DSC) described in the examples. It means a peak. The non-crystalline polyester resin refers to a polyester resin other than the crystalline polyester resin (having no clear endothermic peak as described above) among the polyester resins.

  The crystalline polyester resin is not particularly limited as long as it is defined above. For example, for a resin having a structure in which other components are copolymerized on the main chain of the crystalline polyester resin, the resin is clear as described above. If it shows an endothermic peak, it corresponds to the crystalline polyester resin referred to in the present invention.

  The weight average molecular weight (Mw) of the crystalline polyester resin by gel permeation chromatography analyzer (GPC) is preferably 2,000 to 20,000. Within such a range, the resulting toner particles do not have a low melting point as a whole and are excellent in blocking resistance and excellent in low-temperature fixability.

  The melting point (Tm) of the crystalline polyester resin measured by a differential scanning calorimeter (DSC) is preferably 50 ° C. or higher and lower than 120 ° C., more preferably 60 ° C. or higher and lower than 90 ° C. It is preferable for the melting point of the polyester resin to be in the above-mentioned range since low-temperature fixability and fixability can be appropriately obtained. Regarding the melting point of the crystalline polyester resin, the endothermic peak temperature measured by DSC is defined as the melting point of the crystalline polyester resin. For example, the Tm of the crystalline polyester resin can be obtained using a differential scanning calorimeter in accordance with ASTM D3418. 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. For the sample, an aluminum pan was used, an empty pan was set as a control, the temperature was increased at a temperature increase rate of 10 ° C./min, held at 200 ° C. for 5 minutes, and liquid nitrogen was used from 200 ° C. to 0 ° C. The temperature is lowered at 10 ° C./min, held at 0 ° C. for 5 minutes, and again heated from 0 ° C. to 200 ° C. at 10 ° C./min. By analyzing from the endothermic curve at the second temperature rise, the endothermic peak temperature can be calculated from the maximum peak of the crystalline polyester resin, and the endothermic peak temperature can be defined as Tm.

  The acid value (acid value AV) of the crystalline polyester resin is preferably 5 to 45 mgKOH / g, more preferably 5 to 30 mgKOH / g. If the acid value is 45 mgKOH / g or less, the hygroscopicity is not increased, and the chargeability can be prevented from being lowered even under high humidity. Further, if it is 5 mgKOH / g or more, the dispersion stability of the resin fine particles (resin particles) can be maintained, and this is preferable in terms of easy toner production.

  The crystalline polyester resin is produced from a polyvalent carboxylic acid component and a polyhydric alcohol component. The valences of the polyvalent carboxylic acid component and the polyhydric alcohol component are each preferably 2 to 3, particularly preferably 2 respectively. Therefore, when the valence is 2 respectively as a particularly preferable form (that is, dicarboxylic acid) The acid component and diol component) will be described.

  As the dicarboxylic acid component, an aliphatic dicarboxylic acid is preferably used, and an aromatic dicarboxylic acid may be used in combination. As the aliphatic dicarboxylic acid, it is preferable to use a linear one. By using a linear type, there is an advantage that crystallinity is improved. The dicarboxylic acid component is not limited to one type, and two or more types may be mixed and used. As the aliphatic dicarboxylic acid, it is more preferable to use a linear aliphatic dicarboxylic acid having 2 to 22 carbon atoms constituting the main chain.

  Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. Acid, 1,10-dodecanedicarboxylic acid (1,10-dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid Examples thereof include acids, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, and the like, and lower alkyl esters and acid anhydrides thereof can also be used.

  Among the above aliphatic dicarboxylic acids, from the viewpoint of easy availability, linear aliphatic dicarboxylic acids having 6 to 14 carbon atoms are preferable, and adipic acid and 1,8-octane dicarboxylic acid are preferable. 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, and 1,10-dodecanedicarboxylic acid (1,10-dodecanedioic acid) are more preferable.

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, t-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and the like. Among these, terephthalic acid, isophthalic acid, and t-butylisophthalic acid are preferably used from the viewpoints of availability and emulsification ease.

  The amount of the aliphatic dicarboxylic acid used is preferably 80 component mol% or more, more preferably 90 component mol%, when the entire dicarboxylic acid component for forming the crystalline polyester resin is 100 component mol%. More preferably, it is 100 constituent mol%. When the amount of the aliphatic dicarboxylic acid used is 80 constituent mol% or more, the crystallinity of the crystalline polyester resin can be ensured and excellent low-temperature fixability can be obtained in the manufactured toner. Glossiness is obtained in the formed image, and deterioration of image storage stability due to melting point depression is suppressed. Furthermore, when oil droplets are formed using an oil phase liquid containing the crystalline polyester resin, it is surely emulsified. Can be obtained.

  Moreover, it is preferable to use aliphatic diol as a diol component, and you may contain diols other than aliphatic diol as needed. As the diol component, it is more preferable to use a linear aliphatic diol having 2 to 22 carbon atoms constituting the main chain among the aliphatic diols.

  Examples of the aliphatic diol 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-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18- Examples include octadecanediol and 1,20-eicosanediol. Among these, those having 2 to 14 carbon atoms constituting the main chain are preferable from the viewpoints of availability and reliable low-temperature fixability.

  As the diol component, a branched aliphatic diol can also be used. In this case, from the viewpoint of ensuring crystallinity, it is used together with a linear aliphatic diol and the linear aliphatic diol. It is preferable to use at a higher ratio. By using the linear aliphatic diol in such a high proportion, it is possible to reliably obtain excellent low-temperature fixability in a toner manufactured with ensured crystallinity, and finally form an image. In this case, a decrease in image storability due to a decrease in melting point is suppressed, and further, blocking resistance can be reliably obtained.

  A diol component may be used individually by 1 type and may be used 2 or more types.

  As the diol component for forming the crystalline polyester resin, the content of the aliphatic diol is preferably 80 component mol% or more, more preferably 90 component mol, when the diol component is 100 component mol%. % Or more, and more preferably 100 constituent mol%. When the content of the aliphatic diol in the diol component is 80 constituent mol% or more, the crystallinity of the crystalline polyester resin can be ensured, and excellent low-temperature fixability can be obtained in the manufactured toner. Glossiness can be obtained in an image formed automatically.

  Examples of the diol other than the aliphatic diol include a diol having a double bond and a diol having a sulfonic acid group. Specifically, examples of the diol having a double bond include 2-butene-1,4. -Diol, 3-butene-1,6-diol, 4-butene-1,8-diol and the like. The content of the diol having a double bond in the diol component is preferably 20 constituent mol% or less.

  In addition, monovalent acids such as acetic acid and benzoic acid, monovalent alcohols such as cyclohexanol and benzyl alcohol, benzenetricarboxylic acid, naphthalenetricarboxylic acid, etc. , And their anhydrides and their lower alkyl esters, glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol can also be used in combination.

  The crystalline polyester resin can be synthesized by using a conventionally known method in any combination among the above-described constituent components, and can be used alone or in combination, such as a transesterification method or a direct polycondensation method. it can.

  Specifically, the polymerization can be carried out at a polymerization temperature of 140 ° C. or higher and 270 ° C. or lower. The reaction system is reduced in pressure as necessary, and the reaction is carried out while removing water and alcohol generated during the condensation. When the monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizing solvent and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. In the case where a monomer having poor compatibility exists in the copolymerization reaction, it is preferable that the monomer having poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polycondensed together with the main component.

  The use ratio of the diol component to the dicarboxylic acid component is such that the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] of the diol component to the carboxyl group [COOH] of the dicarboxylic acid component is 1.5 / 1. It is preferable to be set to ˜1 / 1.5, and more preferably 1.2 / 1 to 1 / 1.2. When the use ratio of the diol component and the dicarboxylic acid component is in the above range, a crystalline polyester resin having a desired molecular weight can be obtained with certainty.

  As the catalyst that can be used in the production of the crystalline polyester resin, the same catalyst that can be used in the production of the amorphous polyester resin can be used.

(Content of crystalline resin)
The content of the crystalline resin contained in the toner base particles is preferably 1 to 30% by mass. If the content of the crystalline resin in the toner base particles is 1% by mass or more, the effect of the present invention can be suitably exhibited. Further, when the content of the crystalline resin in the toner base particles is 30% by mass or less, occurrence of thermal aggregation (blocking) of the toner can be avoided. More preferably, the content of the crystalline resin in the toner base particles is 8 to 18% by mass.

  Preferably, the mass of the crystalline resin (in terms of solid content) relative to the total mass (in terms of solid content) of the binder resin and the colorant contained in the toner is 1 to 30% by mass, and more preferably 8 to 18% by mass. In this case, the masses of the binder resin and the colorant can be determined from the masses of the materials introduced into the reaction system when the toner base particles are prepared.

<Styrene acrylic resin>
The binder resin in the toner of the present invention contains a styrene-acrylic ester resin (styrene acrylic resin) in addition to the crystalline resin. The excellent point of the styrene acrylic resin is that the charge control is easy. Further, with such a configuration, the plasticity at the time of heat fixing can be improved. As the monomer constituting the styrene acrylic resin, the same compounds as those mentioned as the monomer constituting the styrene acrylic resin unit in the above-mentioned << Amorphous resin unit other than polyester resin >> can be used.

The styrene acrylic resin is formed by addition polymerization of a styrene monomer and a (meth) acrylic acid ester monomer. The styrene monomer includes those having a structure having a known side chain or functional group in the styrene structure in addition to styrene represented by the structural formula of CH ₂ ═CH—C ₆ H ₅ . In addition, the (meth) acrylic acid ester monomer here refers to an acrylic acid ester derivative or methacrylic acid ester compound represented by CH ₂ ═CHCOOR (R is an alkyl group), It includes an ester compound having a known side chain or functional group in the structure of a methacrylic acid ester derivative or the like. Specific examples of styrene monomers and (meth) acrylic acid ester monomers capable of forming styrene acrylic resins are shown below, but those that can be used to form styrene acrylic resin units used in the present invention are as follows. It is not limited to what is shown below.

  Specific examples of the styrene monomer include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene. , P-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, and the like. These styrene monomers can be used alone or in combination of two or more.

  Specific examples of the (meth) acrylic acid ester monomer include, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate. Acrylate monomers such as stearyl acrylate, lauryl acrylate, and phenyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, Stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl meta Relate, methacrylic acid esters such as dimethyl aminoethyl methacrylate.

  These styrene monomers and (meth) acrylic acid ester monomers can be used alone or in combination of two or more.

  Further, other monomers may be polymerized, and examples thereof include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, and itaconic acid monoester. Alkyl ester, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4- Examples thereof include hydroxybutyl (meth) acrylate and polyethylene glycol mono (meth) acrylate.

  The content of the structural unit derived from the styrene monomer in the styrene acrylic resin is preferably 40 to 89.5 mass% with respect to the total amount of the styrene acrylic resin. Moreover, it is preferable that the content rate of the structural unit derived from the (meth) acrylic acid ester monomer in a styrene acrylic resin is 10-59.5 mass% with respect to the whole quantity of a styrene acrylic resin. By setting it as such a range, it becomes easy to control the plasticity of an amorphous resin.

  The content rate of the structural unit derived from the said other monomer in a styrene acrylic resin is preferable in it being 0.5-30 mass% with respect to the whole quantity of a styrene acrylic resin.

  The method for producing the styrene acrylic resin is not particularly limited, and the styrene acrylic resin can be produced by the same method as the method for forming the styrene acrylic resin unit described in the above section <Amorphous resin unit other than polyester resin>.

  The content of the styrene acrylic resin is preferably 70% by mass or more with respect to the total amount of the binder resin, and if it is within this range, the effect of improving the charging property can be sufficiently exhibited. Although the upper limit of content of the styrene acrylic resin is not particularly limited, for example, it is preferably 99% by mass or less, and more preferably 80% by mass or less.

<Other amorphous resins>
The toner for developing an electrostatic charge image of the present invention may further contain a conventionally known amorphous resin used for the toner in addition to the crystalline resin and the styrene acrylic resin as the binder resin. Specific examples include amorphous polyester resins, acrylic ester resins, and ethylene / vinyl acetate resins, but are not limited thereto.

(Amorphous polyester resin)
The amorphous polyester resin is a polyester resin other than the crystalline polyester resin. That is, it usually has no melting point and has a relatively high glass transition temperature (Tg). More specifically, the glass transition temperature (Tg) is preferably 40 to 90 ° C, and particularly preferably 45 to 80 ° C. The amorphous polyester resin is formed by condensing a polyhydric alcohol component and a polyvalent carboxylic acid component.

  The polyhydric alcohol component is not particularly limited. For example, 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-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, Aliphatic diols such as 1,14-tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol; bisphenols such as bisphenol A and bisphenol F; and ethylene oxide adducts and propylene oxide adducts thereof Alkylene oxides of bisphenols And the like can be illustrated Addendum, As the trihydric or higher polyhydric alcohol components, glycerin, trimethylolpropane, pentaerythritol, sorbitol and the like. Furthermore, cyclohexane dimethanol, cyclohexane diol, neopentyl alcohol, or the like may be used from the viewpoint of production cost and environmental properties. Examples of the polyhydric alcohol component that can form an amorphous polyester resin include 2-butyne-1,4-diol, 3-butyne-1,4-diol, and 9-octadezene-7,12-diol. Saturated polyhydric alcohols can also be used.

  Examples of the divalent carboxylic acid component condensed with the polyhydric alcohol component include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, and naphthalenedicarboxylic acid; Acid, fumaric acid, succinic acid, alkenyl succinic acid, adipic acid, peric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,10-dodecanedicarboxylic acid (1, 10-dodecanedioic acid), 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, aliphatic carboxylic acids such as 1,18-octadecanedicarboxylic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid; and these And lower alkyl esters of acids, acid anhydrides, and the like. May be used alone or two or more.

  Examples of the trivalent or higher carboxylic acid include trimellitic acid, 1,2,4-naphthalenetricarboxylic acid, hemimellitic acid, trimesic acid, merophanic acid, planitic acid, pyromellitic acid, meritic acid, 1,2,3. , 4-butanetetracarboxylic acid, and acid anhydrides, acid chlorides, and lower alkyl esters having 1 to 3 carbon atoms, and trimellitic acid or its anhydride is particularly preferable. These may be used individually by 1 type and may use 2 or more types together.

<Other ingredients>
In addition to the binder resin, the toner base particles may contain an internal additive such as a release agent, a colorant, and a charge control agent, if necessary. Here, the internal additive is a component present in a form contained in the toner base particles.

<Release agent (wax)>
A release agent can be added to the toner base particles. As the release agent, wax is preferably used. Examples of the wax include low molecular weight polyethylene wax, low molecular weight polypropylene wax, Fischer-Tropsch wax, microcrystalline wax, hydrocarbon waxes such as paraffin wax, carnauba wax, pentaerythritol behenate, behenyl behenate, And ester waxes such as behenyl acid. These can be used individually by 1 type or in combination of 2 or more types.

  The melting point of the release agent is preferably 50 to 95 ° C. from the viewpoint of reliably obtaining low-temperature fixability and releasability of the toner. It is preferable that the content rate of a mold release agent is 2-20 mass% with respect to binder resin whole quantity, More preferably, it is 3-18 mass%, More preferably, it is 4-15 mass%.

  The size of the release agent (particles) in the case of obtaining toner base particles by the emulsion association method (emulsion aggregation method) is preferably 10 to 1000 nm, 50 to 500 nm, and more preferably 80 to 500, in terms of volume average particle size. 300 nm is particularly preferred. Within such a range, when the release agent is melted, it is easy to elute to the image surface, which is preferable in terms of image separation.

<Colorant>
In the present invention, the toner base particles may contain a colorant. As the colorant, a known inorganic or organic colorant can be used. For example, carbon black, a magnetic substance, a dye, a pigment, and the like can be arbitrarily used. As the carbon black, channel black, furnace black, acetylene black, thermal black, lamp black, and the like are used. Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, a kind of alloy called Heusler alloy such as manganese-copper-aluminum and manganese-copper-tin, chromium dioxide, and the like can be used.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  Examples of the colorant for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 150, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 184, C.I. I. And CI Pigment Red 222.

  Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

  Further, as a colorant for green or cyan, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.

  These colorants can be used alone or in combination of two or more as required.

  The amount of the colorant added is, for example, in the range of 1 to 30% by mass, preferably 2 to 20% by mass, based on the toner base particles. In such a range, a sufficient image density can be obtained and the charging stability is also excellent.

<Charge control agent>
A charge control agent can be added to the toner base particles as necessary. Various known compounds can be used as the charge control agent. As the charge control agent, various known compounds that can be dispersed in an aqueous medium can be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, fourth compounds. Examples include quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof.

  The content ratio of the charge control agent is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass with respect to the total amount of the binder resin. Such a range is preferable in that a charge rising after toner replenishment can be secured.

  The size of the charge control agent particles is, for example, a number average primary particle size of 10 to 1000 nm, preferably 50 to 500 nm, and more preferably 80 to 300 nm.

[External additive]
The external additive is added to the surface of the toner base particles from the viewpoint of improving the charging performance, fluidity, and cleaning properties of the toner. The toner for developing an electrostatic charge image of the present invention includes, as an external additive, titanium oxide having an average aspect ratio in the range of 2 to 15 derived from the ratio of the number average major axis to the number average minor axis, and the number of the titanium oxides. And spherical silica having a number average particle size larger than the average minor axis and a range of 60 to 150 nm.

<Titanium oxide>
(Average aspect ratio of titanium oxide)
The electrostatic image developing toner according to the present invention contains titanium oxide having an average aspect ratio of 2 to 15 as an external additive. Titanium oxide having an average aspect ratio in the above range has a larger contact area than titanium oxide having a smaller average aspect ratio, and thus hardly moves on the surface of the toner base particles. As a result, the toner base particles can be kept in a uniform covering state with titanium oxide even when subjected to strong stress that continues to be stirred in the developing device. Titanium oxide having an average aspect ratio of less than 2 does not have a sufficient contact area with the toner base, and if the average aspect ratio exceeds 15, the area in contact with the toner base surface, which is a spherical surface, is reduced and deviated from the toner base particles. It becomes easy. Preferably, the average aspect ratio of titanium oxide is 2.5 to 13.5, more preferably 3 to 10.

(Number average minor axis and number average major axis of titanium oxide)
As for the particle diameter of the titanium oxide particles used in the present invention, the number average minor axis is smaller than the number average particle diameter of the spherical silica. This is because the spherical silica does not inhibit the effect of the spacer effect. The number average minor axis and the number average major axis of the titanium oxide are not particularly limited as long as the number average minor axis is smaller than the number average particle diameter of the spherical silica and is within the above average aspect ratio. The diameter is 2 to 20 nm, and the number average major axis is 5 to 200 nm. If the number average major axis of titanium oxide is 200 nm or less, it is difficult to come off from the toner base particles, so that stable image output can be obtained more easily.

  In addition, the number average major axis, the number average minor axis, and the average aspect ratio of titanium oxide can be obtained by the methods described in Examples described later.

(Crystal structure of titanium oxide)
The crystal structure of the titanium oxide particles is preferably a rutile type. Rutile titanium oxide has a higher firing temperature and fewer surface hydroxyl groups than anatase titanium oxide. For this reason, a sufficient resistance value can be ensured regardless of the environment because it is less susceptible to humidity. Therefore, rutile type titanium oxide can impart environmental stability with a higher charge amount to the toner by external addition.

(Production method of titanium oxide)
The titanium oxide can be produced by a known method. Examples of the production method include a sulfuric acid method, a hydrothermal synthesis method using high-temperature and high-pressure water as a solvent, a combustion decomposition method of titanium tetrachloride, and a hydrous hydroxide. Examples include titanium chemical treatment, heating method, wet method, and sol-gel method.

  As an example of a method for producing titanium oxide particles, an outline of a production process of rutile titanium oxide particles by a wet method using alcohol will be described below with reference to the description in JP-A-2004-315356. First, titanium alkoxide is dropped into stirred water-containing methanol. At this time, the growth of the titanium oxide particles can be controlled by the reaction time by adjusting the dropping time and the solvent composition and keeping the dispersed state of the generated particles in good condition by stirring. The longer the reaction time, the more the grain growth in one axial direction proceeds and the average aspect ratio can be controlled. The resulting titanium oxide particles are collected after centrifugation and dried under reduced pressure to obtain amorphous titanium oxide. Rutile type titanium oxide particles can be obtained by heat-treating this amorphous titanium oxide at about 600 to 900 ° C. in air.

  The titanium oxide particles are preferably hydrophobized. A known surface treating agent is used for the hydrophobic treatment. The surface treatment agent may be one kind or two or more kinds, for example, silane coupling agent, silicone oil, titanate coupling agent, aluminate coupling agent, fatty acid, fatty acid metal salt, esterified product thereof and rosin acid. Etc. can be used.

  Examples of the silane coupling agent include dimethyldimethoxysilane, hexamethyldisilazane (HMDS), methyltrimethoxysilane, isobutyltrimethoxysilane, and decyltrimethoxysilane. Examples of the silicone oil include cyclic compounds, linear or branched organosiloxanes, and more specifically, organosiloxane oligomers, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tetramethylcyclohexane. Tetrasiloxane, tetravinyltetramethylcyclotetrasiloxane, and the like can be used.

  The rutile titanium oxide obtained after the heat treatment is added together with the hydrophobizing agent in an appropriate solvent according to the hydrophobizing agent, and the reaction is allowed to proceed by stirring. The reaction product is centrifuged and washed with an appropriate solvent, and then centrifuged again and collected, followed by drying under reduced pressure, whereby the hydrophobized titanium oxide particles according to the present invention can be obtained.

(Addition amount of titanium oxide)
The addition amount of the titanium oxide particles is preferably 0.1 to 1.0 part by mass with respect to 100 parts by mass of the toner base particles. If the amount is 0.1 parts by mass or more with respect to 100 parts by mass of the toner base particles, the toner base particles are appropriately coated, and the effect of reducing the environmental difference in charge amount is sufficiently obtained. It is possible to sufficiently suppress the influence of a decrease in charge amount due to desorption from the base particles and transfer to the carrier particle surface.

<Spherical silica>
(Number average particle diameter of spherical silica)
The toner for developing an electrostatic charge image of the present invention has, as an external additive, a number average particle diameter (number average primary particle diameter) larger than that of titanium oxide, and a number average particle diameter (number average primary particle diameter). Includes spherical silica having a diameter of 60 to 150 nm. In the present specification, the spherical silica means silica particles having a spheroidization degree described later of 0.6 or more. Spherical silica having a number average particle size within the above range is generally larger than other external additives, and exhibits a spacer effect in a two-component developer. By this function, when the two-component developer is agitated in the developing device, it is possible to prevent other small external additives from being embedded in the toner base particles. If the number average particle diameter of the spherical silica is less than 60 nm, a sufficient spacer effect cannot be obtained, and if it is greater than 150 nm, the spherical silica tends to come off from the toner base particles. From the above viewpoint, the number average particle size is required to be in the range of 60 to 150 nm. Preferably, the number average particle diameter of the spherical silica is 80 to 130 nm, more preferably 80 to 110 nm. In addition, the number average particle diameter of the spherical silica can be obtained by the method described in Examples described later.

(Sphericality of spherical silica)
The sphericity of the spherical silica particles used in the present invention is 0.6 or more, preferably 0.8 or more, and more preferably 0.9 or more. Here, the degree of spheroidization refers to Wadell's true degree of spheroidization and is represented by the following formula (1).

Formula (1) Sphericality = (Surface area of a sphere having the same volume as an actual particle) / (Surface area of an actual particle)
The “surface area of a sphere having the same volume as an actual particle” can be obtained by arithmetic calculation from the volume average particle diameter. The “surface area of the actual particles” can be substituted with the BET specific surface area determined using “Powder Specific Surface Area Measuring Device SS-100” (manufactured by Shimadzu Corporation). When the sphericity of the silica particles is less than 0.6, the effect of improving development and transfer is significantly reduced.

(Method for producing spherical silica)
The spherical silica particles are more preferably produced by a sol-gel method. A characteristic of silica particles produced by the sol-gel method is that the particle size distribution is narrow. Thereby, the further spacer effect can be exhibited in a two-component developer.

  As a method for producing the spherical silica particles, a known method can be used. For example, the spherical silica is mainly produced through three steps of hydrolysis, polycondensation, and hydrophobization treatment. You may implement combining a process.

  Spherical silica produced by the sol-gel method is produced by hydrolysis of a hydrocarbyloxysilane compound (such as an alkoxysilane compound or a phenoxysilane compound). Specific examples include the following procedures.

(1) Using ammonia as a catalyst, an alkoxysilane compound such as tetramethoxysilane or tetraethoxysilane is dropped into a mixed solvent of water and alcohol while stirring and reacted. An aqueous suspension of silica particles is thus formed:
(2) An aqueous suspension of silica particles is added to a silane coupling agent such as methyltrimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, hexamethyldisilazane (HMDS), methyltrimethoxysilane, isobutyltrimethoxy. Hydrophobic treatment of the silica particle surface is performed by sequentially adding a hydrophobizing agent such as silane:
(3) The target spherical silica is obtained by removing the solvent from the hydrophobized silica sol and drying.

  The volume average primary particle size of the spherical silica produced by the sol-gel method is controlled by the amount of the hydrocarbyloxysilane compound, ammonia, alcohol, water and other compounds added during the hydrolysis, as well as the reaction temperature, stirring rate, and supply rate. Thus, the desired particle size can be controlled.

(Addition amount of spherical silica)
The addition amount of the spherical silica particles is preferably 0.3 to 1.5 parts by mass with respect to 100 parts by mass of the toner base particles. If it is 0.3 parts by mass or more with respect to 100 parts by mass of the toner base particles, the toner base particles are appropriately coated to obtain a sufficient spacer effect, and if it is 1.5 parts by mass or less, the toner base particles are detached from the toner base particles. This is a range where it is not necessary to consider the influence of separation.

(Other external additives)
The toner for developing an electrostatic charge image according to the present invention includes known inorganic fine particles and organic as other external additives in addition to the above-mentioned titanium oxide having a predetermined average aspect ratio and spherical silica having a predetermined average particle diameter. Fine particles, lubricants and the like may be externally added. Other external additives may be one type or two or more types. Thereby, further improvement in fluidity, cleaning property, charging property, etc. as a toner can be achieved.

  Examples of the inorganic fine particles include, but are not limited to, silica particles, titanium oxide particles, alumina particles, zirconia particles, zinc oxide particles, chromium oxide particles, cerium oxide particles, antimony oxide particles, tungsten oxide particles, tin oxide particles, Examples include tellurium oxide particles, manganese oxide particles, boron oxide particles, and strontium titanate particles. Of these, silica particles, titanium oxide particles, alumina particles, strontium titanate particles, and the like are preferable. The surface of the inorganic fine particles is preferably subjected to a hydrophobic treatment, and a known surface treatment agent is used for the hydrophobic treatment. The surface treatment agent may be one type or two or more types. Specific surface treatment agents are the same as those used for the above-described hydrophobization treatment of titanium oxide.

  As the organic fine particles, for example, spherical organic fine particles having a number average primary particle size of about 10 to 2000 nm can be used. Specifically, homopolymers such as styrene and methyl methacrylate and organic fine particles made of these copolymers can be used.

  The lubricant is used for the purpose of further improving the cleaning property and the transfer property. Examples of the lubricant include zinc stearate, salts of aluminum, copper, magnesium, calcium, and zinc oleate. Of higher fatty acids, such as salts of manganese, iron, copper, magnesium, zinc of palmitic acid, salts of copper, magnesium, calcium, zinc of linoleic acid, salts of calcium, zinc of ricinoleic acid, salts of calcium, etc. Metal salts are mentioned.

<Toner production method>
The method for producing the toner is not particularly limited, and examples thereof include known methods such as a kneading and pulverizing method, a suspension polymerization method, an emulsion aggregation method, a dissolution suspension method, a polyester elongation method, and a dispersion polymerization method.

  Among these, it is preferable to manufacture by an emulsion aggregation method from a viewpoint of the uniformity of a particle size, the controllability of a shape, and the ease of core-shell structure formation. Hereinafter, the toner production method by the emulsion aggregation method will be specifically described, but the present invention is not limited thereto.

(Emulsion aggregation method)
In the emulsion aggregation method, a dispersion of binder resin fine particles (hereinafter also referred to as “resin fine particles”) dispersed by a surfactant or a dispersion stabilizer is mixed with a dispersion of a colorant or the like, if necessary. By adding a flocculant, the toner particles are aggregated (aggregated) until the desired toner particle size is obtained, and thereafter or simultaneously with the aggregation (aggregation), the resin fine particles are fused together to control the shape, thereby controlling the toner. This is a method of forming base particles.

  Here, the resin fine particles may be composite particles formed of a plurality of layers having two or more layers made of resins having different compositions.

  The resin fine particles can be produced, for example, by an emulsion polymerization method, a miniemulsion polymerization method, a phase inversion emulsification method or the like, or can be produced by combining several production methods. When an internal additive is contained in the resin fine particles, it is preferable to use a miniemulsion polymerization method.

  When the toner base particles contain an internal additive, the resin fine particles may contain an internal additive, or a dispersion of internal additive fine particles consisting of only the internal additive is separately prepared. The additive fine particles may be aggregated (aggregated) together when the resin fine particles are aggregated (associated).

  Further, toner base particles having a core-shell structure can also be obtained by an emulsion aggregation method. Specifically, the toner base particles having a core-shell structure are prepared by first binding resin particles for core particles, and if necessary. The core particles are prepared by agglomerating and fusing the colorant fine particles, and then the binder resin fine particles for the shell layer are added to the core particle dispersion to bind the shell layer to the surface of the core particles. It can be obtained by agglomerating and fusing resin fine particles to form a shell layer covering the core particle surface.

  When the toner is produced by the emulsion aggregation method, the toner production method according to a preferred embodiment includes a step of preparing a crystalline resin fine particle dispersion, a styrene acrylic resin fine particle dispersion, and a colorant dispersion (hereinafter also referred to as a preparation step). ) (A), a crystalline resin fine particle dispersion, a styrene acrylic resin dispersion, and a colorant dispersion are mixed to be agglomerated and fused (hereinafter also referred to as agglomeration / fusion process) (b), and toner The shape factor (circularity) control step (c) for controlling the shape factor (circularity) of the toner, and filtration / removal of the toner base particles from the dispersion of the toner base particles to remove the surfactant, etc. It includes a washing step (d), a drying step (e) for drying the toner base particles, and an external additive addition step (f) for adding an external additive to the toner base particles. Hereinafter, each process is explained in full detail.

(A) Preparation Step In more detail, the step (a) includes the following crystalline resin fine particle dispersion preparation step, styrene acrylic resin fine particle dispersion preparation step, and, if necessary, a colorant dispersion preparation step.

  Moreover, a mold release agent dispersion liquid preparation process etc. are included as needed. In addition, in the crystalline resin fine particle dispersion preparation step or the styrene acrylic resin fine particle step, a release agent may be contained in the resin fine particles such as the crystalline resin fine particles or the styrene acrylic resin fine particles, and the release agent includes the release agent. A fine particle dispersion may be prepared separately and added in the aggregation / fusion process.

(A1) Crystalline resin fine particle dispersion preparation step The crystalline resin fine particle dispersion preparation step is a step of synthesizing a crystalline resin and dispersing the crystalline resin in the form of fine particles in an aqueous medium. Is a step of preparing

  Since the manufacturing method of crystalline resin (crystalline polyester resin etc.) is as having described above, the detail is omitted.

  The crystalline resin fine particle dispersion can be prepared by, for example, a method of performing a dispersion treatment in an aqueous medium without using a solvent, or by dissolving the crystalline resin in a solvent such as ethyl acetate to form a solution, and using a disperser, Examples of the method include a method of performing a solvent removal treatment after emulsifying and dispersing in an aqueous medium.

  As a method of dispersing the crystalline resin in the aqueous medium, an oil phase liquid is prepared by dissolving or dispersing the resin in an organic solvent (solvent), and the oil phase liquid is dispersed in the aqueous medium by phase inversion emulsification or the like. There is a method in which an organic solvent is removed after forming oil droplets in a state of being controlled to have a desired particle size by dispersing.

  The aqueous medium refers to a medium containing at least 50% by mass of water, and examples of components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, Examples thereof include methyl ethyl ketone, dimethylformamide, methyl cellosolve, and tetrahydrofuran. Among these, it is preferable to use an organic organic solvent such as methanol, ethanol, isopropanol, and butanol, which is an organic solvent that does not dissolve the resin. Preferably, only water is used as the aqueous medium.

  In addition, when a crystalline polyester resin unit as a crystalline resin contains a carboxyl group, ammonia and water are used in order to dissociate the carboxyl group contained in the unit into an aqueous phase and stably emulsify it in the aqueous phase to facilitate the emulsification smoothly. Sodium oxide or the like may be added.

  As the organic solvent (solvent) used for the preparation of the oil phase liquid, from the viewpoint of easy removal treatment after formation of oil droplets, those having a low boiling point and low solubility in water are preferable. Specific examples include methyl acetate, ethyl acetate, methyl ethyl ketone, isopropyl alcohol, methyl isobutyl ketone, toluene, xylene and the like. These can be used alone or in combination of two or more.

  The amount of the organic solvent (solvent) used (when two or more types are used, the total amount used) is usually 1 to 300 parts by weight, preferably 10 to 200 parts by weight, more preferably 25 to 100 parts by weight of the resin. -100 mass parts. Such a range is preferable in that a dispersion of resin fine particles having a uniform particle size distribution can be obtained.

  Furthermore, ammonia, sodium hydroxide, or the like may be added to the oil phase liquid in order to ionically dissociate the carboxyl group and stably emulsify the aqueous phase to facilitate the emulsification.

  The amount of the aqueous medium used is preferably 50 to 2,000 parts by mass and more preferably 100 to 1,000 parts by mass with respect to 100 parts by mass of the oil phase liquid. By making the usage-amount of an aqueous medium into said range, an oil phase liquid can be emulsified and dispersed to a desired particle size in an aqueous medium. The aqueous medium used here refers to a medium comprising 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran, and an alcohol-based organic solvent that does not dissolve fine particles of crystalline resin (for example, crystalline polyester resin) is used. preferable. In addition, amine or ammonia may be dissolved in the aqueous medium as necessary.

  A dispersion stabilizer may be dissolved in the aqueous medium, and an appropriate amount of a surfactant or resin fine particles may be added for the purpose of improving the dispersion stability of the oil droplets.

  As the dispersion stabilizer, known ones can be used, and examples thereof include inorganic compounds such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite. Since it is necessary to remove the dispersion stabilizer from the toner base particles obtained, it is preferable to use those that are soluble in acids and alkalis such as tricalcium phosphate. It is preferable to use a decomposable one.

  Surfactants include alkylbenzene sulfonate, α-olefin sulfonate, phosphate ester, polyoxyethylene lauryl ether sodium sulfate, sodium alkyldiphenyl ether disulfonate, alkylamine salts, amino alcohol fatty acids Derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, quaternary ammonium salt types such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride Cationic surfactants, nonionic surfactants such as fatty acid amide derivatives, polyhydric alcohol derivatives, alanine, dodecyl di (aminoethyl) glycine, di (octyl) And amphoteric surfactants such as minoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine. Anionic surfactants and cationic surfactants having a fluoroalkyl group can also be used. .

  Examples of the resin fine particles for improving dispersion stability include polymethyl methacrylate resin fine particles, polystyrene resin fine particles, and polystyrene-acrylonitrile resin fine particles.

  Such an emulsified dispersion of the oil phase liquid (the above dispersion treatment) can be performed using mechanical energy, and the disperser for performing the emulsification dispersion is not particularly limited, and is a low-speed shearing type. Dispersers, high-speed shear dispersers, friction dispersers, high-pressure jet dispersers, ultrasonic dispersers such as an ultrasonic homogenizer, and high-pressure impact dispersers and optimizers.

  In dispersing, it is preferable to heat the solution. Although heating conditions are not specifically limited, Usually, it is about 50-90 degreeC.

  The removal of the organic solvent after the formation of the oil droplets was performed by gradually raising the temperature of the dispersion liquid in which the crystalline resin fine particles were dispersed in the aqueous medium in a stirring state, and giving strong stirring in a certain temperature range. Then, it can carry out by operation, such as performing a solvent removal. Alternatively, it can be removed while reducing the pressure using an apparatus such as an evaporator.

  The particle size of the crystalline resin fine particles (oil droplets) in the prepared crystalline resin fine particle dispersion is preferably a volume average particle size of 60 to 1000 nm, more preferably 80 to 500 nm. . Such a range is preferable in terms of stable toner production. In addition, the volume average particle diameter of the resin fine particles (oil droplets) (resin particles) is a laser diffraction / scattering particle size distribution measuring device (Microtrack particle size distribution measuring device “UPA-150” (manufactured by Nikkiso Co., Ltd.)). Can be measured. The volume average particle diameter of the fine particles (oil droplets) can be controlled by the magnitude of mechanical energy during emulsification dispersion.

  Further, the content (solid content concentration) of the crystalline resin fine particles in the crystalline resin fine particle dispersion is preferably in the range of 10 to 50% by mass, more preferably 15 to 40% with respect to 100% by mass of the dispersion. It is the range of mass%. Within such a range, the spread of the particle size distribution can be suppressed and the toner characteristics can be improved.

(A2) Styrene acrylic resin fine particle dispersion preparation step In the styrene acrylic resin fine particle dispersion preparation step as an amorphous resin, a styrene acrylic resin is synthesized, and this styrene acrylic resin is dispersed in the form of fine particles in an aqueous medium. This is a step of preparing a dispersion of acrylic resin fine particles.

  Since the manufacturing method of a styrene acrylic resin is as having described above, the detail is omitted.

  As a method of dispersing a styrene acrylic resin in an aqueous medium, a method (I) of forming styrene acrylic resin fine particles from a monomer for obtaining a styrene acrylic resin and preparing an aqueous dispersion of the styrene acrylic resin fine particles, The styrene acrylic resin was dissolved or dispersed in an organic solvent (solvent) to prepare an oil phase liquid, and the oil phase liquid was dispersed in an aqueous medium by phase inversion emulsification or the like, and the desired particle size was controlled. The method (II) which removes an organic solvent (solvent) after forming the oil droplet of a state is mentioned.

  In the method (I), first, a monomer for obtaining a styrene acrylic resin is added to an aqueous medium together with a polymerization initiator and polymerized to obtain basic particles. Next, it is preferable to use a technique in which a radical polymerizable monomer and a polymerization initiator are added to the dispersion in which the resin fine particles are dispersed, and the radical polymerizable monomer is seed-polymerized to the basic particles. .

  At this time, a water-soluble polymerization initiator can be used as the polymerization initiator. As the water-soluble polymerization initiator, for example, a water-soluble radical polymerization initiator such as potassium persulfate or ammonium persulfate can be preferably used.

  In addition, a commonly used chain transfer agent can be used in the seed polymerization reaction system for obtaining styrene acrylic resin fine particles for the purpose of adjusting the molecular weight of the amorphous resin. Examples of chain transfer agents include mercaptans such as octyl mercaptan, dodecyl mercaptan, t-dodecyl mercaptan; mercaptopropionic acids such as n-octyl-3-mercaptopropionate, stearyl-3-mercaptopropionate; and styrene dimer. Can be used. These can be used alone or in combination of two or more.

  In the method (II), as the organic solvent (solvent) used for the preparation of the oil phase liquid, as described above, from the viewpoint of easy removal after the formation of oil droplets, the boiling point is low and water is used. Those having low solubility in water are preferred, and specific examples include methyl acetate, ethyl acetate, methyl ethyl ketone, isopropyl alcohol, methyl isobutyl ketone, toluene, xylene and the like. These can be used alone or in combination of two or more.

  The amount of the organic solvent (solvent) used (when two or more types are used, the total amount used) is usually 10 to 500 parts by weight, preferably 100 to 450 parts by weight, more preferably 100 parts by weight of styrene acrylic resin. Is 200 to 400 parts by mass.

  The amount of the aqueous medium used is preferably 50 to 2,000 parts by mass and more preferably 100 to 1,000 parts by mass with respect to 100 parts by mass of the oil phase liquid. By making the usage-amount of an aqueous medium into said range, an oil phase liquid can be emulsified and dispersed to a desired particle size in an aqueous medium.

  Similarly to the above, a dispersion stabilizer may be dissolved in the aqueous medium, and a surfactant or resin fine particles may be added for the purpose of improving the dispersion stability of the oil droplets. Good.

  Such emulsification and dispersion of the oil phase liquid can be performed using mechanical energy in the same manner as described above, and the disperser for performing the emulsification and dispersion is not particularly limited. ) Can be used.

  The removal of the organic solvent after the formation of the oil droplets was performed by gradually heating the whole dispersion liquid in which the styrene acrylic resin fine particles were dispersed in the aqueous medium in a stirring state and giving strong stirring in a certain temperature range. Then, it can carry out by operation, such as performing a solvent removal. Alternatively, it can be removed while reducing the pressure using an apparatus such as an evaporator.

  The particle diameter of the styrene acrylic resin fine particles (oil droplets) in the styrene acrylic resin fine particle dispersion prepared by the method (I) or (II) is preferably a volume-based median diameter of 60 to 1000 nm, More preferably, it is 80-500 nm. In addition, this volume average particle diameter is measured by the method as described in an Example. Here, the volume average particle diameter of the oil droplets can be controlled by the magnitude of mechanical energy during emulsification dispersion.

  Further, the content of the styrene acrylic resin fine particles in the styrene acrylic resin fine particle dispersion is preferably in the range of 5 to 50% by mass, and more preferably in the range of 10 to 30% by mass. Within such a range, the spread of the particle size distribution can be suppressed and the toner characteristics can be improved.

(A3) Colorant fine particle dispersion preparation step This colorant fine particle dispersion preparation step is a step of preparing a dispersion of colorant fine particles by dispersing a colorant (pigment) in the form of fine particles in an aqueous medium.

  The said aqueous medium can use the thing similar to the aqueous medium used for dispersion | distribution of the crystalline resin of the said (a1) process. In this aqueous medium, a surfactant or resin fine particles may be added for the purpose of improving dispersion stability. The surfactant and resin fine particles are also as described in the step (a1).

  The dispersion of the colorant can be performed using mechanical energy, and such a disperser is not particularly limited, and the dispersers mentioned above can be used.

  The volume average particle diameter of the colorant fine particles is preferably 10 to 300 nm, and more preferably 100 to 250 nm. Such a range is preferable in that high color reproducibility can be obtained.

  Further, the content (solid content concentration) of the colorant fine particles in the colorant fine particle dispersion is preferably in the range of 10 to 50% by mass, and more preferably in the range of 10 to 40% by mass. Within such a range, there is an effect of ensuring color reproducibility.

(A4) Release Agent Fine Particle Dispersion Preparation Step This release agent fine particle dispersion preparation step is performed as necessary, and a release agent fine particle dispersion in an aqueous medium is obtained by dispersing the release agent in the form of fine particles. Is a step of preparing

  The aqueous medium is as described in the above (a1), and the surfactant and resin fine particles shown in the above (a1) are added to the aqueous medium for the purpose of improving dispersion stability. Also good.

  The release agent can be dispersed using mechanical energy. Such a disperser is not particularly limited, and as mentioned above, a low-speed shear disperser, a high-speed shear Examples thereof include an ultrasonic disperser, a friction disperser, a high-pressure jet disperser, an ultrasonic disperser such as an ultrasonic homogenizer, a high-pressure impact disperser optimizer, and a high-pressure homogenizer. In dispersing the release agent fine particles, heating may be performed as necessary.

(B) Aggregation / fusion process This aggregation / fusion process is carried out using a crystalline resin fine particle dispersion, a styrene acrylic resin fine particle dispersion, and optionally a colorant fine particle dispersion, and optionally a release agent fine particle dispersion. Add and mix other ingredients, etc., and slowly agglomerate while balancing the repulsive force of the fine particle surface by pH adjustment and the agglomeration force by the addition of the flocculant consisting of the electrolyte, and the average particle size and particle size distribution This is a step of forming toner base particles by performing association while controlling and simultaneously controlling the shape by fusing the fine particles by heating and stirring. This agglomeration / fusion process can also be performed using mechanical energy or heating means as required.

(B1) Aggregation step In the aggregation step, first, the obtained dispersions and surfactants are mixed to form a mixed solution, which is then aggregated by heating at a temperature equal to or higher than the glass transition temperature of the styrene acrylic resin as the amorphous resin. To form aggregated particles. For the formation of the aggregated particles, the pH of the mixed solution is preferably adjusted to a range of 8 to 12 and more preferably 9 to 11 under stirring. Such a range is preferable in that agglomeration with a sharp particle size distribution is possible. In order to adjust the pH, for example, hydrochloric acid, sulfuric acid, nitric acid, bicarbonate, ammonia, potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate and the like can be used.

  Next, after adding an alkali metal salt or a salt containing a Group 2 element as a coagulant to the above mixed solution, the mixture is heated to a temperature equal to or higher than the glass transition temperature of the styrene acrylic resin as an amorphous resin for aggregation. Proceed to form aggregated particles (at the same time, the aggregated particles may be fused together).

  Specifically, the crystalline resin fine particle dispersion, the styrene acrylic resin fine particle dispersion, the colorant fine particle dispersion, and, if necessary, the release agent fine particle dispersion are mixed to form a mixed solution. By adding, the crystalline resin fine particles, the styrene acrylic resin fine particles, and the colorant fine particles are aggregated (the particles may be fused at the same time). When the size of the aggregated particles reaches a target size, a salt such as saline is added to stop the aggregation.

  The flocculant used in the present invention is not particularly limited, but those selected from metal salts are preferably used. For example, salts of monovalent metals such as alkali metal salts such as sodium, potassium and lithium, salts of divalent metals such as calcium, magnesium, manganese and copper, salts of trivalent metals such as iron and aluminum Specific examples of the salt include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. A divalent metal salt is preferred. When a divalent metal salt is used, agglomeration can be promoted with a smaller amount. These may be used alone or in combination of two or more.

  In the flocculation step, it is preferable that the standing time (time until heating is started) to be left after adding the flocculant is as short as possible. Thus, after adding the flocculant, it is preferable to start heating the dispersion liquid for aggregation as quickly as possible to a temperature equal to or higher than the glass transition temperature of the styrene acrylic resin. The reason for this is not clear, but there is a possibility that the aggregation state of the particles fluctuates with the passage of the standing time, and the particle size distribution of the obtained toner particles becomes unstable or the surface property fluctuates. Because there is. The standing time is usually within 30 minutes, preferably within 10 minutes. The temperature at which the flocculant is added is not particularly limited, but is preferably not higher than the glass transition temperature of the amorphous resin in the binder resin. That is, it is preferable to quickly raise the temperature by heating after adding the flocculant, and the rate of temperature rise is preferably 0.8 ° C./min or more. The upper limit of the heating rate is not particularly limited, but is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to rapid progress of fusion. Furthermore, after the dispersion liquid for aggregation reaches a temperature equal to or higher than the glass transition temperature of the amorphous resin, the temperature of the dispersion liquid for aggregation is set to a certain time, preferably a volume-based median diameter of 4.5 to 7.0 μm. It is important to keep the fusion by holding until it becomes (first aging step). Moreover, it is preferable to measure the shape factor (circularity) of the particles during aging, and to carry out the first aging step until preferably 0.920 to 1.000.

  As a result, particle aggregation and growth (aggregation of crystalline resin fine particles, styrene acrylic resin fine particles, colorant fine particles, etc.) can be effectively advanced (at the same time, fusion (disappearance of the interface between particles)). The durability of the toner particles finally obtained can be improved.

  In the case of obtaining a binder resin having a core-shell structure, in the first aging step, an aqueous dispersion of a resin that forms a shell layer (preferably the styrene acrylic resin) is further added, The resin forming the shell layer is agglomerated and fused on the surface of the binder resin particles (core particles) having a single layer structure obtained in the above. As a result, a binder resin having a core-shell structure is obtained (shelling step). At this time, following the shelling step, it is preferable to further heat-treat the reaction system until the aggregation and fusion of the shell to the surface of the core particles is further strengthened and the shape of the particles becomes a desired shape. Aging process). This second ripening step may be performed until the average circularity of the toner base particles having a core-shell structure falls within the range of the average circularity.

  When the agglomerated particles have reached a desired particle size, a toner having a structure in which the surface of the core agglomerated particles is coated with an amorphous resin (core-shell) by additionally adding amorphous resin fine particles such as styrene acrylic resin fine particles. Particles) can be produced. In the case of additional addition, a flocculant may be added or pH adjustment may be performed before additional addition. In the case where the core-shell particles are not formed, the following aggregation stopping step may be performed when the aggregated particles before the operation becomes a desired particle size.

  During the aggregation, it is preferable to heat and raise the temperature. At this time, if the temperature becomes higher than the fusing temperature due to heating and temperature rise, the fusing process also proceeds at the same time. The heating rate is preferably 0.1 to 5 ° C./min. Such a range is preferable in that agglomeration with a sharp particle size distribution is possible. Moreover, it is preferable to perform heating temperature (peak temperature) in the range of 40-100 degreeC. Such a range is preferable in that agglomeration with a sharp particle size distribution is possible.

(B2) Aggregation stopping step When the aggregated particles are measured with, for example, a Coulter counter or the like and become a desired average particle diameter, an aggregation stopping agent is added to stop the particle growth. Thereafter, the liquid containing the aggregated particles may be continuously heated and stirred as necessary.

  Examples of the aggregation terminator include alkali metal salts such as ethylenediaminetetraacetic acid (EDTA) and its sodium salt, gluconal, sodium gluconate, potassium citrate and sodium citrate, nitrotriacetate (NTA) salt, GLDA (commercially available L-glutamic acid N, Ndiacetic acid), humic acid and fulvic acid, maltol and ethyl maltol, pentaacetic acid and tetraacetic acid, known water-soluble polymers having both carboxyl and hydroxyl functional groups (polyelectrolytes), hydroxylation Examples thereof include sodium, potassium hydroxide, sodium chloride and aqueous solutions thereof. In the aggregation stopping step, stirring may be performed according to the aggregation step.

(B3) Fusing Step After the fusing step (b2) or simultaneously with the aggregating step (b1), the fusing step is performed by heating the reaction system to a desired fusing temperature, thereby This is a step of forming the fused particles by fusing the constituent fine particles to fuse the aggregated particles.

  The fusing temperature in this fusing step is preferably equal to or higher than the melting point of the crystalline resin, and preferably 0 to 20 ° C. higher than the melting point of the crystalline resin. The heating time may be as long as fusion is performed, and may be performed for about 0.5 to 10 hours. Preferably, for example, while measuring using a flow type particle image analyzer (for example, flow type particle image analyzer FPIA-2000 manufactured by Hosokawa Micron Corporation), a desired shape factor (for example, about 0.96) is obtained. Just do it until you reach it.

  In this aggregation / fusion process, a surfactant may be added to the aqueous medium in order to stably disperse each fine particle in the aggregation system.

  The dispersion of the toner base particles can be cooled to obtain fused particles after the (aggregation) fusion, but when the toner is obtained by the emulsion aggregation method, it will be described later before cooling after the aggregation / fusion process. It is preferable to further have a circularity control step (c).

  The cooling rate is preferably 0.2 to 20 ° C./min, more preferably 2 to 20 ° C./min. Such a range is preferable in that the toner surface after cooling is smooth. The cooling method is not particularly limited, and examples thereof include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system.

(C) Shape Factor (Circularity) Control Step When a toner is obtained by the emulsion aggregation method, it is preferable to have a shape factor (circularity) control step after the aggregation / fusion step. Specifically, the shape factor (circularity) control process includes a heating process for heating the particles obtained in the aggregation / fusion process. The shape factor (circularity) can be controlled by the heating temperature and holding time. By increasing the heating temperature or extending the holding time, the shape factor (circularity) can be made close to 1. However, in order to prevent re-aggregation of the toner base particles, it is preferable not to excessively increase the heating temperature. For the same reason, it is preferable not to excessively increase the holding time.

  The heating temperature in the shape factor (circularity) control process is preferably 70 to 95 ° C, more preferably 70 to 90 ° C, from the viewpoint of bringing the shape factor (circularity) close to 1. Further, the holding time at the heating temperature is not particularly limited, and may be performed until the shape factor (circularity) reaches a target value (a value close to 1). The shape factor (circularity) is controlled by measuring the circularity of the particle diameter with a volume median diameter of 2 μm or more with a shape factor (circularity) measuring device during heating to determine whether the desired circularity is obtained. Control is possible by appropriately determining the above. The volume median diameter is a volume-based median diameter (volume-based median diameter) measured by a precision particle size distribution measuring apparatus (for example, “Multisizer 3” manufactured by Beckman Coulter, Inc.) employing the Coulter principle. It is.

(D) Filtration / Washing Step In this filtration / washing step, the obtained dispersion of toner base particles is cooled to form a cooled slurry, and a solvent such as water is removed from the cooled dispersion of toner base particles. Filter process for solid-liquid separation of toner base particles and filtering the toner base particles, and cleaning process for removing deposits such as surfactant from the filtered toner base particles (cake-like aggregate) And is given. Specific examples of the solid-liquid separation and washing method include a centrifugal separation method, a vacuum filtration method using an aspirator, Nutsche and the like, a filtration method using a filter press, etc., and these are not particularly limited. . In this filtration / washing step, pH adjustment or pulverization may be performed as appropriate. Such an operation may be repeated. By adhering, adhering substances such as a surfactant and an aggregating agent are removed from the toner base particles separated by filtration. The washing process is a washing (water washing) process until the electric conductivity of the filtrate reaches a level of, for example, 5 to 10 μS / cm.

(E) Drying Step In this drying step, the toner base particles that have been washed are subjected to a drying treatment. Dryers used in this drying process include ovens, spray dryers, vacuum freeze dryers, vacuum dryers, stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers, and stirrers A dryer etc. are mentioned, These are not specifically limited. The moisture content measured by Karl Fischer coulometric titration in the dried toner particles (toner base particles) is preferably 5% by mass or less, and more preferably 2% by mass or less.

  In addition, when the dried toner base particles are aggregated by weak interparticle attraction to form an aggregate, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a comb mill, a Henschel mixer, a coffee mill, or a food processor can be used.

(Volume average particle diameter of toner base particles)
The particle size of the toner base particles is preferably small for the purpose of improving the image quality. However, it is said that the toner base particles have a volume average particle size in the range of 2 to 8 μm to achieve both chargeability and fluidity. It is preferable from the viewpoint. As a result, development, transfer, and cleaning do not become difficult, which is preferable. The particle size of the toner base particles is more preferably in the range of 4 to 7 μm from the above viewpoint.

(Average circularity of toner base particles)
The toner for developing an electrostatic charge image of the present invention preferably has an average circularity of the toner base particles represented by the following formula 1 of 0.920 to 1.000 from the viewpoint of improving transfer efficiency.

(Formula 1) Average circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)
As a measurement example for obtaining the above average circularity, measurement using an average circularity measuring device “FPIA-2100” (manufactured by Sysmex) can be mentioned. Specifically, the toner base particles are moistened in an aqueous surfactant solution and dispersed by performing ultrasonic dispersion for 1 minute, and then using “FPIA-2100” in a measurement condition HPF (high magnification imaging) mode. Measurement is performed at an appropriate concentration of 3000 to 10,000 HPF detections.

(F) External additive addition step This external additive addition step is carried out on the surface of the dried toner base particles for the purpose of improving fluidity, chargeability, and cleaning properties, and the like. This is a step of adding external additives such as fine particles, organic fine particles, or a lubricant. Examples of the apparatus used for adding the external additive include various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, a V-type mixer, and a sample mill. Further, sieving classification may be performed as necessary in order to make the particle size distribution of the toner within an appropriate range.

<Developer>
The toner as described above may be used as a one-component magnetic toner containing a magnetic material, mixed with so-called carrier particles and used as a two-component developer, or a non-magnetic toner may be used alone. Any of these can be suitably used. In particular, it is preferably used as a two-component developer containing the toner and carrier particles.

  The two-component developer is obtained by appropriately mixing the toner particles and carrier particles so that the toner particle content (toner concentration) is 4.0 to 8.0% by mass. Can be configured. Examples of the mixing apparatus used for the mixing include a Nauta mixer, a W cone, and a V-type mixer.

  As the carrier constituting the two-component developer, magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used. It is preferable to use ferrite particles.

  As the carrier, it is preferable to use a carrier further coated with a resin or a so-called resin dispersion type carrier in which magnetic particles are dispersed in the resin. The resin composition for coating is not particularly limited, and for example, an olefin resin, a cyclohexyl methacrylate-methyl methacrylate copolymer, a styrene resin, a styrene-acrylic resin, a silicone resin, an ester resin, a fluorine resin, or the like is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, acrylic resin, styrene-acrylic resin, polyester resin, fluororesin, phenol resin, etc. are used. can do.

  The carrier preferably has a volume average particle diameter of 15 to 100 μm, more preferably 25 to 80 μm.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, “parts” or “%” may be used, but “parts by mass” or “% by mass” is indicated unless otherwise specified. Unless otherwise specified, each operation is performed at room temperature (25 ° C.).

[Production of spherical silica]
[Preparation of spherical silica 1]
(1) 630 parts by mass of methanol and 90 parts by mass of 10% aqueous ammonia were added to and mixed with a 3 L reactor equipped with a stirrer, a dropping funnel and a thermometer. To this solution, 900 parts by mass of tetramethoxysilane was added, and tetramethoxysilane was hydrolyzed while stirring to obtain a suspension of silica particles. Subsequently, it heated at 60-70 degreeC, 390 parts of methanol was distilled off, and the aqueous suspension of the silica particle was obtained.

  (2) To the aqueous suspension, 10 parts by mass of methyltrimethoxysilane (equivalent to 0.1 by molar ratio with respect to tetramethoxysilane) was added dropwise at room temperature to hydrophobize the surface of the silica particles.

  (3) After adding 1200 parts by mass of methyl isobutyl ketone to the dispersion thus obtained, the mixture was heated to 80 ° C. to distill off methanol and water. To the resulting dispersion, 250 parts by mass of hexamethyldisilazane was added at room temperature, heated to 120 ° C. and reacted for 3 hours to trimethylsilylate the silica particles. Thereafter, the solvent was distilled off under reduced pressure to prepare spherical silica 1 having a number average particle diameter of 30.2 nm. The sphericity of the spherical silica 1 was 0.6 or more.

[Preparation of spherical silica 2-5]
In the production of the spherical silica 1, the number average particle diameter is adjusted by changing the concentration of the reactant in the system by increasing or decreasing the added mass parts of tetramethoxysilane and hexamethyldisilazane. Spherical silica 2-5 was prepared. When the concentration of the reactant is increased, the number average particle diameter of the produced spherical silica is increased, and when the concentration is decreased, the number average particle diameter of the obtained spherical silica is decreased. The sphericity of the spherical silica 2-5 was 0.6 or more.

[Production of titanium oxide]
Titanium oxide was produced by the following procedure with reference to the description in JP-A-2004-315356.

[Preparation of titanium oxide 1]
(1) 700 parts by mass of methanol was stirred in a 3 L reactor equipped with a stirrer, a dropping funnel, and a thermometer, 450 parts by mass of titanium isopropoxide was dropped, and stirring was continued for 3 minutes. Thereafter, the resulting titanium oxide particles were separated and collected by a centrifugal separator, and then dried under reduced pressure to obtain amorphous titanium oxide.

  (2) The obtained amorphous titanium oxide was heated in a high-temperature electric furnace at 800 ° C. for 5 hours in the air to obtain rutile type titanium oxide particles.

  (3) 500 parts by mass of the obtained rutile titanium oxide and 18 parts by mass of isobutyltrimethoxysilane are added to a 3 L reactor equipped with the stirrer, the dropping funnel and the thermometer described above, and 10 hours in 2 L of toluene. The mixture was stirred and subjected to a hydrophobic treatment. Thereafter, the reaction product was centrifuged to wash the reaction solvent, and then centrifuged again to collect and dried under reduced pressure to obtain rutile-type titanium oxide particles having an average aspect ratio of 1.4.

[Production of titanium oxide 2 to 5]
In the production of titanium oxide 1, the number average minor axis and the number average major axis, and thus the average aspect ratio, were adjusted by changing the stirring reaction time, and titanium oxide particles 2 to 5 shown in Table 2 were produced.

[Production of toner]
[Preparation of colorant fine particle dispersion]
A solution obtained by stirring and dissolving 11.5 parts by mass of sodium n-dodecyl sulfate in 160 parts by mass of ion-exchanged water is stirred, and 24.5 parts by mass of copper phthalocyanine (CI Pigment Blue 15: 3) is added to the solution. Was gradually added. Subsequently, by performing a dispersion treatment using a stirring device “CLEARMIX (registered trademark) W motion CLM-0.8” (manufactured by M Technique Co., Ltd.), the colorant fine particle dispersion having a volume-based median diameter of 126 nm is performed. Liquid [1] was prepared.

[Preparation of Styrene Acrylic Resin Fine Particle Dispersion 1]
(First stage polymerization)
In a reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen introducing device, 4 parts by mass of polyoxyethylene (2) sodium dodecyl ether sulfate and 3000 parts by mass of ion-exchanged water were charged at a stirring speed of 230 rpm under a nitrogen stream. The internal temperature was raised to 80 ° C. while stirring. After raising the temperature, 10 parts by mass of potassium persulfate dissolved in 200 parts by mass of ion-exchanged water was added to obtain a liquid temperature of 75 ° C.
-Styrene 584 parts by mass-N-butyl acrylate 160 parts by mass-A monomer mixture consisting of 56 parts by mass of methacrylic acid is added dropwise over 1 hour, followed by polymerization while heating and stirring at 75 ° C for 2 hours. Thus, a dispersion of resin fine particles [1] was prepared.

(Second stage polymerization)
A reaction vessel equipped with a stirrer, a temperature sensor, a condenser, and a nitrogen introducing device was charged with a solution prepared by dissolving 2 parts by mass of polyoxyethylene (2) sodium dodecyl ether sulfate in 3000 parts by mass of ion-exchanged water, and brought to 80 ° C After heating, 42 parts by mass of resin fine particles [1] prepared above (in terms of solid content) and 70 parts by mass of microcrystalline wax “HNP-0190” (manufactured by Nippon Seiwa Co., Ltd.)
・ Styrene 239 parts by mass ・ N-butyl acrylate 111 parts by mass ・ Methacrylic acid 26 parts by mass ・ n-octyl mercaptan 3 parts by mass A solution dissolved at 80 ° C. was added to the circulation route. A dispersion containing emulsified particles (oil droplets) was prepared by mixing and dispersing for 1 hour using a mechanical disperser “CLEARMIX (registered trademark)” (manufactured by M Technique Co., Ltd.).

  Next, an initiator solution in which 5 parts by mass of potassium persulfate is dissolved in 100 parts by mass of ion-exchanged water is added to this dispersion, and this system is heated and stirred at 80 ° C. for 1 hour to perform polymerization. A dispersion of resin fine particles [2] was prepared.

(Third stage polymerization)
A solution prepared by dissolving 10 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water was further added to the dispersion of the resin fine particles [2] prepared as described above.
-Styrene 380 mass parts-N-butyl acrylate 132 mass parts-Methacrylic acid 39 mass parts-n-octyl mercaptan 6 mass parts monomer mixture liquid was dripped over 1 hour. After completion of the dropwise addition, polymerization was performed by heating and stirring for 2 hours, and then cooled to 28 ° C. to obtain a styrene acrylic resin fine particle dispersion 1.

[Preparation of crystalline resin fine particle dispersion 1]
(Synthesis of crystalline resin fine particles 1)
As a material for the crystalline polyester resin, 220 parts by mass of sebacic acid (molecular weight 202.25) which is a polyvalent carboxylic acid compound and 298 parts by mass of 1,12-dodecanediol (molecular weight 202.33) which is a polyhydric alcohol compound; Was put in a reaction vessel equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and heated to 160 ° C. to dissolve. Thereafter, 2.5 parts by mass of tin (II) 2-ethylhexanoate and 0.2 parts by mass of gallic acid were added, the temperature was raised to 210 ° C., and the reaction was performed for 8 hours. Furthermore, reaction was performed at 8.3 kPa for 1 hour, and the crystalline resin 1 was obtained.

  About the obtained crystalline resin 1, the DSC curve was acquired on the conditions of the temperature increase rate of 10 degree-C / min using the differential scanning calorimeter "Diamond DSC" (made by Perkin Elmer). The measurement result of the melting point (Tm) by the method of measuring the endothermic peak top temperature is 82.8 ° C., and the molecular weight by GPC “HLC-8120GPC” (manufactured by Tosoh Corporation) was measured. Was 28000.

(Preparation of crystalline resin fine particle dispersion 1)
The crystalline resin 1 was dissolved in 100 parts by mass and 400 parts by mass of ethyl acetate. Subsequently, 25 mass parts of 5.0 mass% sodium hydroxide aqueous solution was added, and the resin solution was prepared. This resin solution was put into a container having a stirrer, and 638 parts by mass of a 0.26% by mass aqueous sodium dodecyl sulfate solution was added dropwise over 30 minutes while stirring the resin solution. During the dropwise addition of the aqueous sodium dodecyl sulfate solution, the liquid in the reaction vessel became cloudy, and after the entire amount of the aqueous sodium dodecyl sulfate solution was dropped, an emulsion was prepared in which the resin fine particles were uniformly dispersed. Next, the emulsion is heated to 40 ° C., and ethyl acetate is distilled off under a reduced pressure of 150 hPa using a diaphragm vacuum pump “V-700” (manufactured by BUCHI). A crystalline resin fine particle dispersion 1 was obtained.

[Preparation of Crystalline Resin Fine Particle Dispersion 2 Made of Hybrid Resin]
(Synthesis of crystalline resin 2 made of hybrid resin)
220 parts by mass of sebacic acid (molecular weight 202.25) as the polyvalent carboxylic acid compound of the material of the crystalline polyester resin unit, and 298 parts by mass of 1,12-dodecanediol (molecular weight 202.33) as the polyhydric alcohol compound In a reaction vessel equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, the mixture was heated to 160 ° C. and dissolved. On the other hand, a solution of 46 parts by mass of styrene, 12 parts by mass of n-butyl acrylate, 4 parts by mass of dicumyl peroxide, and 3 parts by mass of acrylic acid as both reactive monomers, which are materials of a vinyl resin unit mixed in advance. The mixture was added dropwise over 1 hour using a dropping funnel. Stirring was continued for 1 hour while maintaining at 170 ° C., and after polymerizing styrene, n-butyl acrylate and acrylic acid, 2.5 parts by mass of tin (II) 2-ethylhexanoate, 0.2 parts by mass of gallic acid Was added, the temperature was raised to 210 ° C., and the reaction was carried out for 8 hours. Furthermore, reaction was performed at 8.3 kPa for 1 hour to obtain a crystalline resin 2 made of a hybrid crystalline polyester resin.

(Preparation of crystalline resin fine particle dispersion 2)
The crystalline resin 2 was dissolved in 100 parts by mass and 400 parts by mass of ethyl acetate. Subsequently, 25 mass parts of 5.0 mass% sodium hydroxide aqueous solution was added, and the crystalline resin solution was prepared. While the crystalline resin solution was put into a container having a stirrer and stirred, 638 parts by mass of a 0.26% by mass aqueous sodium dodecyl sulfate solution was added dropwise over 30 minutes. During the dropwise addition of the aqueous sodium dodecyl sulfate solution, the liquid in the reaction vessel became cloudy, and after the entire amount of the aqueous sodium dodecyl sulfate solution was dropped, an emulsion was prepared in which the crystalline resin fine particles were uniformly dispersed. Next, the emulsion is heated to 40 ° C., and by using a diaphragm vacuum pump “V-700” (manufactured by BUCHI), ethyl acetate is distilled off under a reduced pressure of 150 hPa, whereby a hybrid crystalline polyester resin is obtained. A crystalline resin fine particle dispersion 2 was obtained.

[Preparation of toner base particles 1]
(Aggregation / fusion process)
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device, 300 parts by mass (in terms of solid content) of styrene acrylic resin fine particle dispersion 1 and 60 parts by mass of solid resin fine particle dispersion 1 (solid) ), 1100 parts by mass of ion-exchanged water, and 40 parts by mass of the colorant fine particle dispersion [1] (in terms of solids), and after adjusting the liquid temperature to 30 ° C., 5N sodium hydroxide aqueous solution was added. In addition, the pH was adjusted to 10. Next, an aqueous solution in which 60 parts by mass of magnesium chloride was dissolved in 60 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. The temperature was raised after holding for 3 minutes, and the temperature of the system was raised to 85 ° C. over 60 minutes, agglomerating while maintaining 85 ° C., and the particle growth reaction was continued. In this state, the particle size of the aggregated particles was measured with “Coulter Multisizer 3” (manufactured by Beckman Coulter). When the volume-based median diameter reached 6 μm, 40 parts by mass of sodium chloride was added to ion-exchanged water. An aqueous solution dissolved in 160 parts by mass is added to stop particle growth, and further, as a ripening process, fusion between particles is advanced by heating and stirring at a liquid temperature of 80 ° C., and an average circularity measuring device “FPIA” -2100 "(manufactured by Sysmex), after confirming that the average circularity was 0.920 or more, the mixture was cooled to 30 ° C to prepare a dispersion of toner base particles 1.

(Washing / drying process)
The produced dispersion of toner base particles 1 was subjected to solid-liquid separation with a basket-type centrifuge “MARK III model number 60 × 40 + M” (manufactured by Matsumoto Machine Co., Ltd.) to form a wet cake of toner base particles. The wet cake was washed with ion exchange water at 40 ° C. until the electric conductivity of the filtrate reached 5 μS / cm with the basket-type centrifuge, and then transferred to “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.) The toner base particles 1 were produced by drying until the water content reached 0.5% by mass.

(Calculation method of content of constituent resin in toner base particles)
The content (% by mass) of the crystalline resin in the toner base particles is calculated by the following formula. In addition, content (mass%) is defined from the mass of the material thrown into the reaction system, and the mass of each material is the value converted into solid content.

Crystalline resin amount (parts by mass) / (styrene acrylic resin amount (parts by mass) + crystalline resin amount (parts by mass) + colorant amount (parts by mass)) × 100
Similarly, the content (mass%) of the styrene acrylic resin in the toner base particles is calculated by the following formula. The mass of each material is a value in terms of solid content.

Amount of styrene acrylic resin (parts by mass) / (Amount of styrene acrylic resin (parts by mass) + Amount of crystalline resin (parts by mass) + Amount of colorant (parts by mass)) × 100
For example, the content (% by mass) of the crystalline resin in the toner base particles 1 is 60 parts by mass / (300 parts by mass + 60 parts by mass + 40 parts by mass) × 100 = 15% by mass.

  Further, the content (% by mass) of the styrene acrylic resin in the toner base particles 1 is obtained as 300 parts by mass / (300 parts by mass + 60 parts by mass + 40 parts by mass) × 100 = 75% by mass.

[Preparation of toner base particles 2 to 4]
In the same manner as in the preparation of the toner base particles 1, the raw material mass was changed so that the content of the styrene acrylic resin and the content of the crystalline resin (crystalline polyester resin) in the toner base particles became the values shown in Table 3. Toner base particles 2 to 4 were prepared. The crystalline resin contained in the toner base particles 3 is all a hybrid crystalline polyester resin, and the toner base particles 4 do not contain a crystalline resin (crystalline polyester resin).

(External additive addition process)
The following external additives are added to the toner base particles 1 (100 parts by mass) prepared above, and added to the Henschel mixer model “FM20C / I” (manufactured by Nippon Coke Kogyo Co., Ltd.). Was set to 40 m / s, and the number of revolutions of the stirring blade was set, followed by stirring for 20 minutes to prepare toner 1. The temperature of the mixed powder during mixing of the external additive was set to 40 ± 1 ° C.

-Titanium oxide 3 0.2 part by mass-Spherical silica 2 1.0 part by mass [Preparation of toner 2-28]
In the production of toner 1, the amount of crystalline resin (crystalline polyester resin) and the amount of styrene acrylic resin in the production of toner base particles are changed according to Table 4 below, and the external additive formulation in toner production is changed according to Table 4 below. Toners 2 to 28 were produced in the same manner as described above except for the above.

[Production of Developers 1 to 28]
To the toners 1 to 28 produced above, a ferrite carrier having a volume average particle diameter of 60 μm was added so that the toner content (toner concentration) in the two-component developer was 7% by mass. Then, it mixed for 30 minutes with the V-type mixer, and obtained as each corresponding two-component developer 1-28.

<Number average particle diameter of titanium oxide and spherical silica>
In an electron micrograph using a scanning electron microscope (SEM) “JEM-7401F” (manufactured by JEOL Ltd.), the particle diameters of titanium oxide and spherical silica were measured, and the average value of n = 20 was determined to obtain the number average. The particle size was taken. For titanium oxide, the major axis (maximum diameter when close to a sphere) and the short diameter (minimum diameter when close to a sphere) were measured. Similarly, with respect to the major axis and minor axis, the average value of n = 20 was determined and used as the number average major axis and the number average minor axis, respectively.

<Average aspect ratio of titanium oxide>
Using the number average major axis and minor axis determined by the above method, (major axis / minor axis) = (number average major axis) / (number average minor axis) was determined, which was defined as the average aspect ratio.

<Measuring method of melting point of crystalline polyester resin>
The melting point of the crystalline polyester resin was measured by a differential calorimeter (DSC). Specifically, using a differential scanning calorimeter “Diamond DSC” (manufactured by PerkinElmer Co., Ltd.), a first temperature raising process in which the temperature is raised from 0 ° C. to 200 ° C. at an elevation rate of 10 ° C./min, a cooling rate of 10 ° C./min. Measured according to the measurement conditions (temperature rise / cooling conditions) through the cooling process of cooling from 200 ° C. to 0 ° C. and the second temperature raising process of raising the temperature from 0 ° C. to 200 ° C. at a rising / lowering speed of 10 ° C./min. Based on the DSC curve obtained by this measurement, the endothermic peak top temperature derived from the crystalline polyester resin in the first temperature raising process is taken as the melting point. As a measurement procedure, 3.0 mg of crystalline polyester resin is sealed in an aluminum pan and set in a sample holder of “Diamond DSC”. The reference used an empty aluminum pan.

[Evaluation]
As an evaluation apparatus, a commercially available digital full-color multifunction peripheral “bizhub PRO C6500” (manufactured by Konica Minolta, “bizhub” is a registered trademark of the company) was used.

[Evaluation 1: Low-temperature fixability]
A copying machine “bizhub PRO C6500” (manufactured by Konica Minolta Co., Ltd.) was prepared by modifying the fixing device so that the surface temperature of the fixing heat roller could be changed in the range of 100 to 210 ° C. This was loaded with the above-mentioned developers 1 to 28, respectively. Changed the fixing experiment to fix a solid image with a toner adhesion amount of 11 mg / 10 cm ² on A4 size plain paper (basis weight 80 g / m ² ) to increase the set fixing temperature in increments of 1 ° C. from 140 ° C. The process was repeated up to 200 ° C. Among fixing experiments in which image smear due to low temperature offset is not visually observed, the fixing temperature of the fixing experiment relating to the lowest fixing temperature was evaluated as the minimum fixing temperature. It means that the lower the minimum fixing temperature is, the better the low temperature fixing property is.

-Evaluation criteria-
A: Minimum fixing temperature is less than 155 ° C.
○: Minimum fixing temperature of 155 ° C. or higher and lower than 160 ° C.,
X: The minimum fixing temperature is 160 ° C. or higher.

[Evaluation 2: Charge amount stability (environmental difference and durability stability)]
As a test image on high-quality paper (65 g / m ² ) of A4 size in a copying machine “bizhub PRO C6500” (manufactured by Konica Minolta Co., Ltd.) at normal temperature and humidity (temperature 20 ° C., humidity 50% RH) Five prints forming a belt-like solid image with a printing rate of 5% were printed, and the toner charge amount at that time was measured. Similarly, printing under a high-temperature and high-humidity (30 ° C., 80% RH) environmental condition is performed to form a strip-shaped solid image having a printing rate of 5% as a test image on high-quality paper (65 g / m ² ) of A4 size. Ten sheets were printed, and the toner charge amount after printing 5 sheets and after printing 100,000 sheets was measured and evaluated according to the following evaluation criteria. The charge amount was measured by sampling the two-component developer in the developing device and using a blow-off charge amount measuring device “TB-200” (manufactured by Toshiba Chemical Corporation). The smaller the toner charge amount difference Δ (hereinafter referred to as “environmental difference Δ”) when printing 5 sheets under normal and normal humidity and high temperature and high humidity, the less the toner charge is affected by the external environment. If it is less than 10 μC / g, it is judged as acceptable without any practical problem. In addition, the lower the toner charge amount difference Δ (hereinafter referred to as the durability drop value Δ) after printing 5 sheets and 100,000 sheets after printing in a high-temperature and high-humidity environment, the more stable toner output is possible. If it is less than 10 μC / g, it is judged as acceptable without any practical problem.

-Evaluation criteria-
(Environmental difference Δ)
A: Environmental difference Δ of toner charge amount after printing 5 sheets under normal temperature and normal humidity environment and high temperature and high humidity environment is less than 5 μC / g,
○: The environmental difference Δ of the toner charge amount after printing 5 sheets in a normal temperature and high humidity environment and a high temperature and high humidity environment is 5 μC / g or more and less than 10 μC / g,
X: The environmental difference Δ of the toner charge amount after printing 5 sheets in a normal temperature and normal humidity environment and a high temperature and high humidity environment is 10 μC / g or more.

(Durability drop value Δ)
A: Under a high temperature and high humidity environment, after the printing of 5 sheets and after the printing of 100,000 sheets, the durability reduction value Δ of the toner charge amount is less than 5 μC / g,
○: After printing 5 sheets and after printing 100,000 sheets in a high temperature and high humidity environment, the durability reduction value Δ of the toner charge amount is 5 μC / g or more and less than 10 μC / g,
X: Durability decrease value Δ of toner charge amount is 10 μC / g or more after printing 5 sheets and after printing 100,000 sheets in a high temperature and high humidity environment.

[Evaluation 3: Image quality (granularity)]
In a copying machine “bizhub PRO C6500” (manufactured by Konica Minolta Co., Ltd.), a printing rate of 5 as a test image on high-quality paper (65 g / m ² ) of A4 size under high temperature and high humidity (30 ° C., 80% RH) environmental conditions. Prints 100,000 sheets to form a belt-shaped solid image, and outputs a gradation pattern with a gradation ratio of 32 steps after printing 5 sheets and after printing 100,000 sheets. Therefore, it was evaluated. Graininess is evaluated by applying a Fourier transform process considering MTF (Modulation Transfer Function) correction to the reading value of the gradation pattern CCD, and measuring the GI value (Graininess Index) according to the human specific visual sensitivity. The GI value was determined. The smaller the GI value, the better. If the fluctuation value Δ is less than 0.020, it is judged as acceptable without any practical problem. In addition, this GI value is a value published in Journal of the Imaging Society of Japan 39 (2), 84/93 (2000).

-Evaluation criteria-
A: In a high-temperature and high-humidity environment, after printing 5 sheets and after printing 100,000 sheets, the fluctuation value Δ of the GI value is less than 0.010,
○: Under a high temperature and high humidity environment, after printing 5 sheets and after printing 100,000 sheets, the variation value Δ of the GI value is 0.010 or more and less than 0.020,
X: The variation value Δ of the GI value is 0.020 or more after printing 5 sheets and after printing 100,000 sheets in a high temperature and high humidity environment.

  The results obtained are shown in Table 4 below.

  From the results shown in Table 4, the toners of Examples 1 to 11 have a small decrease in charge amount even under high temperature and high humidity, a small decrease in charge amount even under high durability conditions, and also have low temperature fixability. And achieves both of the above performances. On the other hand, the toners of Comparative Examples 1 to 17 could not achieve all the above performances. As described above, by using the present invention, it is possible to produce a toner that can be fixed at a low temperature but can stably output an image regardless of a printing environment or a use situation.

  Among the toners of Examples 1 to 11, the toners of Examples 1 to 9 and 11 in which the content of the crystalline resin is in the range of 1 to 30% by mass exceed 30% by mass. As compared with the toner of Example 10, the charge amount durability lowering value was smaller. It is estimated that this is because if the content of the crystalline resin is in the range of 1 to 30% by mass, the content of the crystalline polyester containing a large amount of hydroxyl groups does not increase too much.

  Moreover, in Example 11 in which the crystalline resin has a hybrid structure, excellent results were shown in all evaluation items as compared with other examples. This is because the crystalline polyester resin is hybridized to prevent the crystalline polyester resin from being localized on the surface of the toner base particles due to the difference in affinity between the styrene acrylic resin and the crystalline polyester resin. This is probably because of this. Since the polyester resin having a large number of hydroxyl groups in the structure is not unevenly distributed on the surface, it is considered that the environmental stability and the durability stability are further improved because the polyester resin is less affected by the external environment, particularly humidity.

Claims (6)

An electrostatic charge image developing toner comprising toner base particles containing a styrene acrylic resin and a crystalline resin as a binder resin, and an external additive,
The external additive includes titanium oxide having an average aspect ratio in the range of 2 to 15 derived from the ratio of the number average major axis to the number average minor axis, and a number average particle size larger than the number average minor axis of the titanium oxide. And a toner for developing an electrostatic charge image, comprising spherical silica having a range of 60 to 150 nm.   The electrostatic image developing toner according to claim 1, wherein the crystalline resin is a crystalline polyester resin.   The electrostatic image developing toner according to claim 1, wherein the crystalline polyester resin is a hybrid crystalline polyester resin containing an amorphous resin other than the crystalline polyester resin as a unit.   The electrostatic charge image developing toner according to claim 1, wherein a content of the crystalline resin in the toner base particles is 1 to 30% by mass.   The electrostatic image developing toner according to claim 1, wherein the titanium oxide has a rutile crystal structure.   A two-component developer for developing an electrostatic charge image, comprising the toner for developing an electrostatic charge image according to any one of claims 1 to 5 and carrier particles.