JP6547493B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to a toner for electrostatic charge image development.

  In recent years, with the spread of digital printing, it has been increasingly desired to improve the quality of output images. Fine and high-quality image formation requires that the particle size distribution of the toner be sharp. By matching the development behavior of each toner particle, the fine dot reproducibility can be improved. Here, by making the resin constituting the toner contain a styrene acrylic resin, it is possible to apply a toner manufacturing method suitable for narrowing particle size distribution such as the emulsion aggregation method (see, for example, Patent Document 1).

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

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

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

  However, 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, so that the surface composition of the toner base particles becomes uneven. As a result, the toner base particles can not have a sufficient amount of charge, and particularly under high temperature and high humidity, the tendency of the decrease in the amount of charge strongly appears.

  Also, in order to secure low temperature fixability, it is necessary to design the toner base particles soft. 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 is used. Burial is likely to occur. Due to this, the charge amount reduction due to the deterioration of the toner under high stress, which is mentioned in the low coverage large amount printing and the like, and the image quality deterioration of the output image accompanied therewith are caused.

  Therefore, according to the present invention, a toner for developing an electrostatic charge image containing toner base particles in which a crystalline resin is introduced into a styrene acrylic resin and an external additive can be fixed at a low temperature and stable regardless of the printing environment or the use condition. To provide a toner capable of outputting an image with high image quality.

  As a result of intensive studies to solve the above problems and achieve the above object, the present inventors have determined that the toner base particles including a styrene acrylic resin as a binder resin and a crystalline resin, and an external additive. It has been found that the above problems can be solved by using, as an external additive, titanium oxide having a predetermined average aspect ratio and spherical silica having a predetermined number average particle diameter in the toner for developing a charge image. Completed the invention.

  That is, the above-mentioned subject concerning the present invention is solved by the following means.

1. A toner for developing an electrostatic charge image comprising toner base particles comprising a styrene acrylic resin and a crystalline resin as a binder resin, and an external additive,
The external additive is titanium oxide whose average aspect ratio is 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 average particle diameter is larger than the number average minor axis of the titanium oxide And a spherical silica having a range of 60 to 150 nm.

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

  3. The above-mentioned 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. Or 2. The toner for developing an electrostatic charge image according to the above.

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

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

  6. Said 1. To 5. A two-component developer for electrostatic image development, comprising the toner for electrostatic image development according to any one of the above and carrier particles.

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

One embodiment of the present invention is a toner for developing an electrostatic charge image, which comprises a toner base particle containing a styrene acrylic resin and a crystalline resin as a binder resin, and an external additive,
The external additive is titanium oxide whose average aspect ratio is 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 average particle diameter is larger than the number average minor axis of the titanium oxide And a 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 properties as a binder resin, and an amorphous resin It is considered to use and. By using a styrene acrylic resin having a sharp particle size distribution of the obtained toner and capable of providing a sufficient charge amount as the amorphous resin, the sharp melt property is improved.

  However, since the affinity between the crystalline resin and the styrene acrylic resin is poor, and the crystalline resin is difficult to be taken in the styrene acrylic resin, there is a problem that the surface composition of the toner base particles becomes uneven. The When a crystalline resin having a low resistance is present in the vicinity of the surface of the toner base particle, the toner can not have a sufficient charge amount, and particularly under high temperature and high humidity, the tendency of the charge amount reduction tends to appear. A decrease in the charge amount of toner causes an image defect such as a decrease in image density and fog.

  In the present invention, the environmental stability of the toner charge amount is improved by externally adding titanium oxide. At this time, by using titanium oxide having an average aspect ratio in the range of 2 to 15, the contact area between the titanium oxide and the toner base particles becomes large. Therefore, the movement of the titanium oxide particles on the surface of the toner base particles is less likely to occur. As a result, it is possible to prevent the aggregation of the external additive to the unevenness of the surface of the toner base particle, which may occur when the toner is highly stressed. Moreover, since the uniform coating state of titanium oxide is maintained for a long time, environmental stability of the charge amount of the toner can be maintained.

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

  The spacer effect by the spherical silica also plays a role of preventing the crystalline resin present in the vicinity of the surface of the toner base particle from contacting the carrier particle when the toner is used as a two-component developer together with the carrier particle. Have. As a result, it is possible to suppress the charge leakage of the toner through the low-resistance crystalline resin, and the effect of securing the charge amount of the toner can be enhanced regardless of the printing environment or the printing situation. 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.

  From the above, the toner of the present invention can output a high quality image and fix at low temperature with narrow particle size distribution, and can stably output an image regardless of the printing environment or the use condition.

  Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments. Further, in the present specification, “X to Y” indicating a range means “X or more and Y or less”. Moreover, unless otherwise indicated, measurement of operation, a physical property, etc. is measured on the conditions of room temperature (25 degreeC) / 40 to 50% of relative humidity.

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

<Crystalline resin>
The crystalline resin in the present invention indicates, in differential scanning calorimetry (DSC), a resin having not a stepwise endothermic change but a clear endothermic peak. A clear endothermic peak specifically means a peak which shows that the half-width of the endothermic peak is within 15 ° C. when measured, for example, at a temperature rising rate of 10 ° C./min in differential scanning calorimetry (DSC) Do. Examples of the crystalline resin include crystalline polyester resin and crystalline vinyl resin. There is no particular limitation, but a crystalline polyester resin is preferable for realizing low temperature fixability. As crystalline polyester resin, the well-known polyester resin obtained by the polycondensation reaction of carboxylic acid (polyvalent carboxylic acid) more than bivalence and alcohol (polyhydric alcohol) more than bivalence can be used.

  Furthermore, it is more preferable that the said crystalline polyester resin is a hybrid crystalline polyester resin containing non-crystalline resin other than crystalline polyester resin as a unit. The non-crystalline resin unit is preferably made of a resin of the same type as the non-crystalline 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 enhanced, and the hybrid resin is more easily incorporated 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. In addition, environmental stability can be improved.

  The crystalline polyester resin and the hybrid crystalline polyester resin will be described below.

(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 non-crystalline resin unit other than polyester resin refers to the part originating in non-crystalline resin other than polyester. That is, it refers to a molecular chain having the same chemical structure as that constituting an amorphous resin other than polyester resin.

«Crystalline polyester resin unit»
The crystalline polyester resin unit is a portion derived from a known polyester resin obtained by the polycondensation reaction of a divalent or higher valent carboxylic acid (polyvalent carboxylic acid) and an alcohol having a second or higher valent (polyhydric alcohol) In Differential Scanning Calorimetry (DSC), it refers to a resin unit having a distinct endothermic peak, not a stepwise endothermic change. Specifically, the distinct endothermic peak means that the half-width of the endothermic peak is within 15 ° C. when measured at a temperature rising rate of 10 ° C./min in differential scanning calorimetry (DSC) described in the examples. It means the peak.

  The crystalline polyester resin unit is not particularly limited as long as it is defined above. For example, for a resin having a structure in which another component is copolymerized in the main chain of a crystalline polyester resin unit, or a resin having a structure in which a crystalline polyester resin unit is copolymerized in a main chain 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 as referred to in the present invention.

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

  The number of valences of the polyvalent carboxylic acid component and the polyhydric alcohol component is preferably 2 to 3 and particularly preferably 2 respectively. , Dicarboxylic acid component and diol component) will be described.

  As the dicarboxylic acid component, aliphatic dicarboxylic acids are preferably used, and aromatic dicarboxylic acids may be used in combination. It is preferable to use a linear type aliphatic dicarboxylic acid. Using a linear type has the advantage of improving the crystallinity. The dicarboxylic acid component is not limited to one type, and two or more types may be mixed and used.

  Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 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, 18-octadecane dicarboxylic acid etc. are mentioned, Moreover, these lower alkyl esters and an acid anhydride 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 aromatic dicarboxylic acids that can be used together with aliphatic dicarboxylic acids include, for example, terephthalic acid, isophthalic acid, orthophthalic acid, t-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, etc. Can be mentioned. Among these, terephthalic acid, isophthalic acid and t-butyl isophthalic acid are preferably used from the viewpoint of easy availability and ease of emulsification.

  As a dicarboxylic acid component for forming a crystalline polyester resin unit, the content of aliphatic dicarboxylic acid is preferably 50 constituent mole% or more, more preferably 70 constituent mole% or more, and still more preferably It is 80 constituent mole% or more, and particularly preferably 100 constituent mole%. By setting the content of the aliphatic dicarboxylic acid in the dicarboxylic acid component to 50 constituent mol% or more, the crystallinity of the crystalline polyester resin unit can be sufficiently secured.

  Moreover, as a diol component, it is preferable to use aliphatic diol, and you may make diol other than aliphatic diol be contained as needed. As the aliphatic diol, it is preferable to use a linear type. Using a linear type has the advantage of improving the crystallinity. The diol component may be used alone or in combination of two or more.

  Examples of aliphatic diols 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, and more preferably an aliphatic diol having 6 to 12 carbon atoms, because the effect of the present invention is easily obtained.

  Examples of diols other than aliphatic diols that are optionally used include diols having a double bond and diols having a sulfonic acid group. Specifically, examples of the diol having a double bond include 2 And -butene-1,4-diol, 3-butene-1,6-diol, 4-butene-1,8-diol and the like.

  As a diol component for forming a crystalline polyester resin unit, it is preferable that content of an aliphatic diol shall be 50 structural-mol% or more, More preferably, it is 70 structural-mol% or more, More preferably, 80 structural It is at least mol%, particularly preferably 100 constituent mol%. By setting the content of the aliphatic diol in the diol component to 50 constituent mol% or more, it is possible to secure the crystallinity of the crystalline polyester resin unit and to obtain excellent low temperature fixability to the manufactured toner. The glossiness is obtained in the finally formed image.

  The ratio of use 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 and the carboxyl group [COOH] of the dicarboxylic acid component is 1.5 / 1. It is preferably 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 polycondensing (esterification) the polyvalent carboxylic acid and the polyhydric alcohol using a known esterification catalyst. Can.

  As a catalyst which can be used in the production of the crystalline polyester resin unit, alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; aluminum, zinc, manganese, antimony, titanium, tin, zirconium And metal compounds such as germanium; phosphorous acid compounds; phosphoric acid compounds; and amine compounds. Specific examples of the tin compound include dibutyltin oxide, tin octylate, tin dioctylate, and salts thereof. Examples of titanium compounds include titanium alkoxides such as tetranormal butyl titanate, tetraisopropyl titanate, tetramethyl titanate and tetrastearyl titanate; titanium acylates such as polyhydroxytitanium stearate; titanium tetraacetylacetonate, titanium lactate, titanium triethanolamide And titanium chelates such as nitrate. As a germanium compound, germanium dioxide etc. can be mentioned. Further, as the aluminum compound, oxides such as polyaluminum hydroxide, aluminum alkoxide and the like can be mentioned, and tributylaluminate etc. can be mentioned. 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 preferably 0.5 to 10 hours. During the polymerization, the reaction system may be depressurized if necessary.

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

  Here, the hybrid resin includes, in addition to the crystalline polyester resin unit, an amorphous resin unit other than the polyester resin described in detail below. The hybrid resin may be in any form such as a block copolymer or a graft copolymer as long as it contains an amorphous resin unit other than the crystalline polyester resin unit and the polyester resin. It is preferable that it is united. 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.

  Further, 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, orientation of a crystalline polyester resin unit can be raised more, and crystallinity of a hybrid resin can be improved.

  The hybrid resin may further have a substituent such as a sulfonic acid group, a carboxyl group or a urethane group introduced. The introduction of the substituent may be in a 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 resin (sometimes referred to simply as "amorphous resin unit" in the present specification) control the affinity between the amorphous resin and the hybrid resin that constitute the binder resin. Is an essential unit for By the presence of the amorphous resin unit, the affinity between the hybrid resin and the amorphous resin is improved, the hybrid resin is easily taken into the amorphous resin, and charging uniformity and the like can be improved. .

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

  In addition, 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 the 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. Is preferred. In addition, a glass transition temperature can be calculated | required by DSC measurement described in the Example, and let the onset temperature in the 1st temperature rising process be 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 another component is copolymerized in the main chain by an amorphous resin unit, or a resin having a structure in which an amorphous resin unit is copolymerized in a main chain consisting of other components If the toner to be contained has the above amorphous resin unit, the resin corresponds to the hybrid resin having the amorphous resin unit in the present invention.

  The amorphous resin unit is preferably made of a resin of the same type as the amorphous resin (that is, a resin other than the hybrid resin) contained in the binder resin. With 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 and the like are further improved.

  Here, "homogeneous resin" means that characteristic chemical bonds are commonly included in the repeating unit. Here, the “characteristic chemical bond” is described in the Material and Material Research Organization (NIMS) material and material database (http://polymer.nims.go.jp/PoLyInfo/guide/jp/term_polymer.html). According to the "polymer classification" of That is, polyacrylic, polyamide, polyanhydride, polycarbonate, polydiene, polyester, polyhaloolefin, polyimide, polyimine, polyimine, polyketone, polyolefin, polyether, polyphenylene, polyphosphazen, polysiloxane, polystyrene, polysulfide, polysulfone, polyurethane, polyurea Chemical bonds that constitute 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 species having the above-described chemical bond is used as a constituent unit in the chemical structure of a plurality of monomer species constituting the copolymer. Refers to resins that share common chemical bonds. Therefore, even when the characteristics of the resin itself are different from each other, or even when the molar component ratio of the monomer species constituting the copolymer is different from each other, the same kind of resin as long as they have characteristic chemical bonds in common It is regarded as

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

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

  The vinyl resin unit is not particularly limited as long as it is obtained by polymerizing a vinyl compound, and examples thereof include acrylic acid ester resin units, styrene-acrylic acid ester resin units, and ethylene / vinyl acetate resin units. One of these may be used alone, or two or more of these may be used in combination.

  Among the above-mentioned vinyl resin units, a styrene-acrylic acid ester resin unit (styrene acrylic resin unit) is preferable in consideration of the plasticity at the time of heat fixing. Therefore, hereinafter, a styrene acrylic resin unit as an amorphous resin unit will be described.

The styrene acrylic resin unit is formed by addition polymerization of at least a styrene monomer and a (meth) acrylic acid ester monomer. The styrene monomer referred to here includes, in addition to styrene represented by the structural formula of CH ₂ CHCH—C ₆ H ₅ , one having a structure having a known side chain or a functional group in the styrene structure. In addition to the acrylic acid ester compound and methacrylic acid ester compound represented by CH ₂ CHCHCOOR (R is an alkyl group), the (meth) acrylic acid ester monomer referred to here is an acrylic acid ester derivative or methacrylic acid. It contains 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 styrene acrylic resin unit are shown below, but those usable for forming 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- Dimethylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene and the like can be mentioned. These styrene monomers may be used alone or in combination of two or more.

  Moreover, as a specific example of the (meth) acrylic acid ester monomer, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate Acrylic acid ester 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 the present specification, the term "(meth) acrylic acid ester monomer" is a generic term for "acrylic acid ester monomer" and "methacrylic acid ester monomer". "Methyl acrylate" is a generic term for "methyl acrylate" and "methyl methacrylate".

  These acrylic acid ester monomers or methacrylic acid ester monomers may be used alone or in combination of two or more. That is, to form a copolymer using a styrene monomer and two or more acrylic acid ester monomers, and using a styrene monomer and two or more methacrylic acid ester monomers to form a copolymer It is possible to form a united body or to form a copolymer by using a styrene monomer and an acrylic acid ester monomer and a methacrylic acid ester monomer in combination.

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

  Furthermore, in the amorphous resin unit, it is preferable that, in addition to the styrene monomer and the (meth) acrylic acid ester monomer, a compound for chemically bonding to the crystalline polyester resin unit is also addition polymerized. . Specifically, it is preferable to use a compound which is ester-bonded to a hydroxyl group [-OH] derived from a polyhydric alcohol or a carboxyl group [-COOH] derived from a polyvalent carboxylic acid, which is contained in the above-mentioned crystalline polyester resin unit. Therefore, the amorphous resin unit is addition-polymerizable to the above-mentioned styrene monomer and (meth) acrylic acid ester monomer, and has a carboxyl group [-COOH] or hydroxyl group [-OH]. It is preferable to further polymerize the compound.

  Such compounds include, for example, 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.

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

  The formation method of 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 an azo-based or diazo-based polymerization initiator and a peroxide-based polymerization initiator shown below.

  As an 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.

  Examples of peroxide polymerization initiators include 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 of forming resin fine particles (resin particles) by the 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 salts thereof, 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 to 10% by mass, and further preferably 7% by mass to 9% by mass. By setting it as the said range, sufficient crystallinity can be provided to 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 is a method capable of forming a polymer having a structure in which the crystalline polyester resin unit and the non-crystalline resin unit are molecularly bonded. It is not a thing. As a specific manufacturing method of a hybrid resin, the method shown below is mentioned, for example.

(1) Method of producing a hybrid resin by performing polymerization reaction in which an amorphous resin unit is polymerized in advance and a crystalline polyester resin unit is formed in the presence of the amorphous resin unit In this method, first, Amorphous resin unit is formed by addition reaction of monomers (preferably, styrene monomer and vinyl monomer such as (meth) acrylic acid ester monomer) constituting the above-mentioned amorphous resin unit. . Next, in the presence of the amorphous resin unit, the polyvalent carboxylic acid and the polyhydric alcohol are polymerized to form a crystalline polyester resin unit. At this time, a hybrid resin is formed by causing a condensation reaction of a polyvalent carboxylic acid and a polyhydric alcohol, and causing an addition reaction of a polyvalent carboxylic acid or a polyhydric alcohol to an amorphous resin unit.

  In the above-mentioned method, it is preferable to incorporate portions which can react with each other in the crystalline polyester resin unit or the amorphous resin unit. Specifically, at the time of formation of the amorphous resin unit, in addition to the monomers constituting the amorphous resin unit, the carboxyl group [-COOH] or hydroxyl group [-OH] remaining in the crystalline polyester resin unit A compound having a site capable of reacting with and a site capable of reacting with an amorphous resin unit is also used. That is, the crystalline polyester resin unit may be chemically bonded to the amorphous resin unit by reacting this compound with the carboxyl group [-COOH] or hydroxyl group [-OH] in the crystalline polyester resin unit. it can.

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

  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) Method of forming a crystalline polyester resin unit and an amorphous resin unit respectively and combining them to produce a hybrid resin In this method, first, a polyvalent carboxylic acid and a polyvalent 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 monomers constituting the above-mentioned amorphous resin unit are addition-polymerized to form an amorphous resin unit. At this time, it is preferable to incorporate portions 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 | part is as above-mentioned, the detailed description is abbreviate | omitted.

  Next, the crystalline polyester unit formed above is reacted with the non-crystalline resin unit to form a hybrid resin of a structure in which the crystalline polyester resin unit and the non-crystalline resin unit are molecularly bonded. it can.

  In addition, when the above reactive part 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, and A method may be employed in which a compound having a moiety capable of binding to the crystalline polyester resin unit and the amorphous resin unit is introduced. Then, 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) Method of producing a hybrid resin by performing a polymerization reaction of forming a crystalline polyester resin unit in advance and forming an amorphous resin unit in the presence of the crystalline polyester resin unit In this method, first, A condensation reaction of polyvalent carboxylic acid and polyvalent alcohol is carried out to carry out polymerization to form a crystalline polyester resin unit. Next, in the presence of the crystalline polyester resin unit, the monomers constituting the amorphous resin unit are polymerized to form an amorphous resin unit. At this time, as in the case of the above (1), it is preferable to incorporate portions which can react with each other in the crystalline polyester resin unit or the amorphous resin unit. In addition, since the method of incorporating such a reactive site | part is as above-mentioned, the detailed description is abbreviate | 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 formation methods of (1) to (3), the method of (1) is easy to form a hybrid resin having a structure in which a crystalline polyester resin chain is grafted to an amorphous resin chain, and the production process is simplified. It is preferable because it can be done. In the method of (1), since the crystalline 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 the hybrid resin suitable for the toner defined in the present invention can be surely formed.

(Crystalline polyester resin)
The crystalline polyester resin is not particularly limited, and is a known polyester resin obtained by the polycondensation reaction of a divalent or higher carboxylic acid (polyvalent carboxylic acid) and an alcohol having two or more valences (polyhydric alcohol). Can be applied widely. Here, among the polyester resins described above, the crystalline polyester resin refers to a resin having not a stepwise endothermic change but a clear endothermic peak in differential scanning calorimetry (DSC). Specifically, the distinct endothermic peak means that the half-width of the endothermic peak is within 15 ° C. when measured at a temperature rising rate of 10 ° C./min in differential scanning calorimetry (DSC) described in the examples. It means the peak. Among the polyester resins, the non-crystalline polyester resin refers to polyester resins other than the above-mentioned crystalline polyester resin (that do not have the above-mentioned distinct endothermic peak).

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

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

  The melting point (Tm) of the crystalline polyester resin by differential scanning calorimetry (DSC) is preferably 50 ° C. or more and less than 120 ° C., and more preferably 60 ° C. or more and less than 90 ° C. When the melting point of the polyester resin is in the above range, low temperature fixability and fix separation are preferably obtained. The melting point of the crystalline polyester resin is defined as the endothermic peak temperature measured by DSC as the melting point of the crystalline polyester resin. For example, the Tm of a crystalline polyester resin can be obtained using a differential scanning calorimeter according to ASTM D3418. The temperature correction of the detection part of this device uses the melting point of indium and zinc, and the heat of fusion uses the heat of fusion of indium. For samples, use an aluminum pan, set an empty pan for control, raise the temperature at a heating rate of 10 ° C / min, hold at 200 ° C for 5 minutes, and use liquid nitrogen from 200 ° C to 0 ° C. The temperature is lowered at 10 ° C./min, held at 0 ° C. for 5 minutes, and the temperature is raised again from 0 ° C. to 200 ° C. at 10 ° C./min. The endothermic curve at the time of the second temperature rise is analyzed, the endothermic peak temperature can be calculated from the maximum peak of the crystalline polyester resin, and the endothermic peak temperature can be used as Tm.

  The acid value (acid value AV) of the crystalline polyester resin is preferably 5 to 45 mg KOH / g, more preferably 5 to 30 mg KOH / g. If the acid value is 45 mg KOH / g or less, it is preferable from the viewpoint that the chargeability can be prevented from being lowered even under high humidity without the hygroscopicity becoming high. Further, if it is 5 mg KOH / g or more, the dispersion stability of the resin fine particles (resin particles) can be maintained, which is preferable in that toner production can be easily performed.

  Crystalline polyester resins are produced from polyhydric carboxylic acid components and polyhydric alcohol components. The number of valences of the polyvalent carboxylic acid component and the polyhydric alcohol component is preferably 2 to 3 and particularly preferably 2 respectively. The acid component and the diol component will be described.

  As the dicarboxylic acid component, aliphatic dicarboxylic acids are preferably used, and aromatic dicarboxylic acids may be used in combination. It is preferable to use a linear type aliphatic dicarboxylic acid. Using a linear type has the advantage of improving the crystallinity. 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 in which the number of carbon atoms constituting the main chain is 2 to 22.

  Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 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 and 1,18-octadecanedicarboxylic acid, and lower alkyl esters and acid anhydrides thereof can also be used.

  Among the above-mentioned aliphatic dicarboxylic acids, from the viewpoint of easy availability, it is preferably a linear aliphatic dicarboxylic acid having 6 to 14 carbon atoms, and adipic acid or 1,8-octanedicarboxylic acid More preferably, it is 1,9-nonane dicarboxylic acid, 1,10-decane dicarboxylic acid, or 1,10-dodecane dicarboxylic acid (1,10-dodecanedioic acid).

  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-butyl isophthalic acid are preferably used from the viewpoint of easy availability and ease of emulsification.

  The amount of the aliphatic dicarboxylic acid used is preferably 80 constituent mol% or more, more preferably 90 constituent mol%, based on 100 constituent mol% of the entire dicarboxylic acid component for forming the crystalline polyester resin. The above, more preferably 100 constituent mole%. By setting the amount of the aliphatic dicarboxylic acid to be 80% by mole or more, it is possible to secure the crystallinity of the crystalline polyester resin and to obtain excellent low temperature fixability to the manufactured toner, and finally, While glossiness is obtained in the formed image and a decrease in image storability due to melting point depression is suppressed, further, when oil droplets are formed using an oil phase liquid containing the crystalline polyester resin, an emulsified state is surely achieved. You can get

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

  Examples of aliphatic diols 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 viewpoint of easy availability and expression of reliable low temperature fixability.

  Although a branched aliphatic diol can be used as the diol component, in this case, from the viewpoint of securing crystallinity, it is used together with a linear aliphatic diol, and the linear aliphatic diol It is preferable to use at a high ratio of As described above, by using a higher proportion of the linear aliphatic diol, excellent low temperature fixability can be surely obtained for the toner manufactured with securing of crystallinity, and an image formed finally In the above, the decrease in the image storability due to the melting point depression is suppressed, and furthermore, the blocking resistance is surely obtained.

  The diol component may be used alone or in combination of two or more.

  As a diol component for forming a crystalline polyester resin, it is preferable that content of an aliphatic diol shall be 80 structure mol% or more, more preferably 90 structure mol, when a diol component is 100 structure mol%. % Or more, more preferably 100% by mole. By setting the content of the aliphatic diol in the diol component to 80 constituent mol% or more, the crystallinity of the crystalline polyester resin can be secured, and a low temperature fixability excellent in the toner manufactured can be obtained and the final The glossiness is obtained in the image formed in the

  Examples of diols other than aliphatic diols include diols having a double bond, and diols having a sulfonic acid group. Specifically, as a diol having a double bond, for example, 2-butene-1,4 -Diol, 3-butene-1, 6-diol, 4-butene-1, 8-diol etc. are mentioned. The content of the diol having a double bond in the diol component is preferably at most 20 constituent mole%.

  If necessary, for the purpose of adjusting the acid value and hydroxyl value etc., a monovalent acid such as acetic acid and benzoic acid, a monohydric alcohol such as cyclohexanol and benzyl alcohol, benzene tricarboxylic acid, naphthalene tricarboxylic acid, etc. And their anhydrides and their lower alkyl esters, glycerin, trimethylol ethane, trimethylol propane, pentaerythritol and other trivalent alcohols may be used in combination.

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

  Specifically, the polymerization can be carried out at a polymerization temperature of 140 ° C. or more and 270 ° C. or less, and if necessary, the inside of the reaction system is depressurized, and the reaction is carried out while removing water and alcohol generated during condensation. If the monomers are not soluble or miscible at the reaction temperature, a high boiling point solvent may be added as a dissolution co-solvent and dissolved. The polycondensation reaction is carried out while distilling off the dissolution auxiliary solvent. When a monomer having poor compatibility in the copolymerization reaction is present, it is preferable to condense the monomer having poor compatibility with the acid or alcohol to be subjected to polycondensation in advance and then to conduct polycondensation with the main component.

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

  The catalyst usable in the production of the crystalline polyester resin may be the same as the catalyst usable in the production of the non-crystalline polyester resin described above.

(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 effects of the present invention can be suitably exhibited. When the content of the crystalline resin in the toner base particles is 30% by mass or less, the 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 (in terms of solid content) of the crystalline resin is 1 to 30% by mass, more preferably 8 to 18% by mass, based on the total mass (in terms of solid content) of the binder resin and the colorant contained in the toner. In this case, the mass of the binder resin and the colorant can be determined from the mass of the material introduced into the reaction system in the preparation of the toner base particles.

<Styrene acrylic resin>
The binder resin in the toner of the present invention contains, in addition to the crystalline resin, a styrene-acrylic ester resin (styrene acrylic resin). The superior point of styrene acrylic resin is that charge control is easy. Moreover, the plasticity at the time of heat fixation can be improved by setting it as such a structure. As a monomer which comprises a styrene acrylic resin, the thing similar to the compound mentioned as a monomer which comprises a styrene acrylic resin unit in the term of said <non-crystalline 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 is, 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 to the acrylic acid ester compound and methacrylic acid ester compound represented by CH ₂ CHCHCOOR (R is an alkyl group), the (meth) acrylic acid ester monomer referred to here is an acrylic acid ester derivative or It contains 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 monomer and (meth) acrylic acid ester monomer capable of forming styrene acrylic resin are shown below, but those usable for forming a styrene acrylic resin unit used in the present invention 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 and 2,4-dimethylstyrene P-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene and the like. These styrene monomers may be used alone or in combination of two or more.

  Moreover, as a specific example of the (meth) acrylic acid ester monomer, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate Acrylic acid ester 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 may be used alone or in combination of two or more.

  In addition, other monomers may be polymerized, and examples thereof include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, monoalkyl ester of maleic acid, mono itaconic acid, and the like. Alkyl ester, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4- Hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, etc. are mentioned.

  It is preferable that the content rate of the structural unit derived from the styrene monomer in styrene acrylic resin is 40-89.5 mass% with respect to the whole quantity of styrene acrylic resin. Moreover, it is preferable in the styrene acrylic resin that the content rate of the structural unit derived from the (meth) acrylic acid ester monomer 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 amorphous resin.

  It is preferable that the content rate of the structural unit derived from the said other monomer in a styrene acrylic resin is 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 a styrene acrylic resin unit described in the section of << noncrystalline resin unit other than polyester resin >>.

  The content of the styrene acrylic resin is preferably 70% by mass or more based on the total amount of the binder resin, and within this range, the effect of improving the chargeability can be sufficiently exhibited. The upper limit of the content of the styrene acrylic resin is not particularly limited, but is preferably 99% by mass or less, and more preferably 80% by mass or less.

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

(Amorphous polyester resin)
Amorphous polyester resin is polyester resin other than the said crystalline polyester resin. That is, they usually do not have a melting point and have a relatively high glass transition temperature (Tg). More specifically, the glass transition temperature (Tg) is preferably 40 to 90 ° C., particularly preferably 45 to 80 ° C. The amorphous polyester resin is formed by condensation of a polyhydric alcohol component and a polyhydric carboxylic acid component.

  Examples of the polyhydric alcohol component include, but are not limited to, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 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, ethylene oxide adducts of these, propylene oxide adducts, etc. 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, cyclohexanedimethanol, cyclohexanediol, neopentyl alcohol and the like may be used from the viewpoint of production cost and environment. Moreover, as a polyhydric alcohol component which can form an amorphous polyester resin, inconsistencies such as 2-butyne-1,4-diol, 3-butyne-1,4-diol, 9-octadezen-7,12-diol, etc. Saturated polyhydric alcohols can also be used.

  Examples of the divalent carboxylic acid component to be condensed with the polyhydric alcohol component include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalene dicarboxylic acid, etc .; maleic anhydride Acid, fumaric acid, succinic acid, alkenyl succinic acid, adipic acid, speric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,10-dodecanedicarboxylic acid (1,1 Aliphatic carboxylic acids such as 10-dodecanedioic acid), 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid; Lower alkyl esters of acids of the formula, acid anhydrides, etc. May be used alone or two or more.

  Examples of the trivalent or higher carboxylic acids include trimellitic acid, 1,2,4-naphthalenetricarboxylic acid, hemimellitic acid, trimesic acid, merophonic acid, prenitic acid, pyromellitic acid, mellitic acid, 1, 2, 3 And 4-butanetetracarboxylic acid, and their acid anhydrides, acid chlorides, C1-C3 lower alkyl esters, and the like, with trimellitic acid or its anhydride being particularly preferred. These may be used alone or in combination of two or more.

<Other ingredients>
The toner base particles may contain internal additives such as a releasing agent, a coloring agent, and a charge control agent, as needed, in addition to the above-mentioned binder resin. Here, the internal additive is a component present in a form contained in the toner base particles.

<Mold release agent (wax)>
A release agent can be added to the toner base particles. Wax is preferably used as the release agent. Waxes include, for example, 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 behenyl behenate, citric acid And ester waxes such as behenyl acid. These can be used singly or in combination of two or more.

  Further, the melting point of the releasing agent is preferably 50 to 95 ° C. from the viewpoint of surely obtaining the low temperature fixing property and the releasing property of the toner. The content ratio of the release agent is preferably 2 to 20% by mass, more preferably 3 to 18% by mass, and still more preferably 4 to 15% by mass with respect to the total amount of the binder resin.

  The size of the releasing 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 nm in volume average particle diameter. 300 nm is particularly preferred. Within such a range, when the release agent is melted, it is easily eluted to the image surface, which is preferable in view of image separation.

<Colorant>
In the present invention, the toner base particles may contain a colorant. As the colorant, known inorganic or organic colorants can be used. For example, carbon black, magnetic substances, dyes, pigments and the like can be optionally used. As 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 which do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, an alloy of the type called a Heusler alloy such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide and the like can be used.

  As the black colorant, for example, carbon black such as furnace black, channel black, acetylene black, thermal black, lamp black and the like, and magnetic powder such as magnetite and ferrite are also used.

  As colorants for magenta or red, 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. Pigment red 222 and the like.

  Moreover, as a coloring agent for orange or yellow, 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. Pigment yellow 185 and the like.

  Further, as colorants 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. Pigment green 7 and the like.

  These colorants may 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. Within such a range, sufficient image density can be obtained, and charge stability is also excellent.

<Charge control agent>
A charge control agent can be added to the toner base particles as required. As the charge control agent, various known compounds can be used. As the charge control agent, various known compounds which can be dispersed in an aqueous medium can be used. Specifically, nigrosine dyes, metal salts of naphthenic acids or higher fatty acids, alkoxylated amines, fourth compounds And 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. Within such a range, it is preferable in that charging rising after toner replenishment can be secured.

  The size of the charge control agent particles is, for example, 10 to 1000 nm as a number average primary particle size, 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, the fluidity, or the cleaning property as a toner. The toner for electrostatic image development of the present invention comprises, 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 titanium oxides. And spherical silica having a number average particle diameter larger than the average short diameter and having a range of 60 to 150 nm.

<Titanium oxide>
(Average aspect ratio of titanium oxide)
The toner for developing an electrostatic charge image 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 is difficult to move on the surface of the toner base particles because the contact area is large compared to titanium oxide having a smaller average aspect ratio. As a result, the toner base particles can be maintained in a uniform coating state by the titanium oxide even in the case of a strong stress which keeps stirring in the developing device. When the average aspect ratio is less than 2, the contact area with the toner base is not sufficient, and when the average aspect ratio exceeds 15, the area in contact with the toner base surface, which is a spherical surface, is reduced and it deviates from the toner base particle It will be easier. Preferably, the average aspect ratio of titanium oxide is 2.5 to 13.5, more preferably 3 to 10.

(Number average minor diameter and number average major diameter of titanium oxide)
As for the particle size of the titanium oxide particles used in the present invention, the number average short diameter is smaller than the number average particle size of spherical silica. This is to prevent inhibition of the spacer effect of the spherical silica. The number average short diameter and the number average long diameter of titanium oxide are not particularly limited as long as the number average short diameter is smaller than the number average particle diameter of spherical silica and the above average aspect ratio can be obtained. 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 separate from the toner base particles, and stable image output can be obtained more easily.

  The number average major axis, the number average minor axis, and the average aspect ratio of titanium oxide can be determined by the method described in the examples below.

(Crystal structure of titanium oxide)
The crystal structure of the titanium oxide particles is preferably rutile. Rutile type titanium oxide has a higher calcination temperature and less surface hydroxyl groups than anatase type titanium oxide. From this, it is possible to secure a sufficient resistance value without being influenced by humidity and regardless of the environment. Therefore, by externally adding rutile type titanium oxide, it is possible to impart to the toner environmental stability of higher charge amount.

(Method of producing titanium oxide)
The titanium oxide may be produced by a known method. For example, a sulfuric acid method, a hydrothermal synthesis method using water at high temperature and high pressure as a solvent, a combustion decomposition method of titanium tetrachloride, a hydrous oxidation Chemical treatment of titanium, heating method, wet method, sol-gel method and the like can be mentioned.

  As an example of the method for producing titanium oxide particles, the outline of the production process of rutile type titanium oxide particles by a wet method using an alcohol will be described below with reference to the contents described in JP-A-2004-315356. First, titanium alkoxide is dropped into stirred aqueous 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 dispersion state of the produced particles well by stirring. As the reaction time is longer, grain growth in one axial direction proceeds and the average aspect ratio can also be controlled. The resulting titanium oxide particles are collected after centrifugation and dried under reduced pressure to obtain amorphous titanium oxide. By heat-treating this amorphous titanium oxide in air at about 600 to 900 ° C., rutile type titanium oxide particles can be obtained.

  The titanium oxide particles are preferably hydrophobized. A known surface treatment agent is used for the hydrophobization treatment. The surface treatment agent may be used alone or in combination of two or more, and for example, silane coupling agents, silicone oils, titanate coupling agents, aluminate coupling agents, fatty acids, fatty acid metal salts, esters thereof and rosin acids Etc. can be used.

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

  Rutile-type titanium oxide obtained after heat treatment is added together with a hydrophobizing agent to a suitable solvent according to the hydrophobizing agent, and the reaction is allowed to proceed with stirring. After the reaction product is centrifuged and washed with a suitable solvent, it is again centrifuged and collected, and dried under reduced pressure to obtain the hydrophobized titanium oxide particles according to the present invention.

(Addition amount of titanium oxide)
The addition amount of the titanium oxide particles is preferably 0.1 to 1.0 parts by mass with respect to 100 parts by mass of the toner base particles. If it is 0.1 parts by mass or more with respect to 100 parts by mass of toner base particles, the toner base particles are appropriately coated to sufficiently obtain the environmental difference reducing effect of the charge amount, and if it is 1.0 parts by mass or less The influence of the reduction of the charge amount due to the detachment from the base particle and the transfer to the carrier particle surface can be sufficiently suppressed.

<Spherical silica>
(Number average particle size of spherical silica)
In the toner for electrostatic image development of the present invention, the number average particle diameter (number average primary particle diameter) is larger than the number average short diameter of titanium oxide as an external additive, and the number average particle diameter (number average primary particle diameter) Is 60 to 150 nm. In the present specification, spherical silica means silica particles having a degree of sphericity of 0.6 or more described later. Spherical silica having a number average particle diameter in the above range is generally larger than other external additives, and exhibits a spacer effect in a two-component developer. By this action, when the two-component developer is stirred in the developing device, it is possible to suppress the other small external additive from being buried in the toner base particles. When the number average particle size of the spherical silica is less than 60 nm, a sufficient spacer effect can not be obtained, and when it is more than 150 nm, the toner is easily detached from the toner base particle. From the above viewpoint, the number average particle diameter is required to be in the range of 60 to 150 nm. Preferably, the number average particle size of the spherical silica is 80 to 130 nm, more preferably 80 to 110 nm. In addition, the number average particle diameter of spherical silica can be calculated | required by the method described in the below-mentioned Example.

(The degree of sphericity 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 sphericity refers to Wadell's true sphericity, and is represented by the following formula (1).

Formula (1) Spheroidization degree = (surface area of a sphere having the same volume as actual particles) / (surface area of actual particles)
In addition, "the surface area of the sphere which has the same volume as an actual particle | grain" can be calculated | required by arithmetic calculation from volume average particle diameter. Moreover, "the surface area of an actual particle | grain" can be substituted by the BET specific surface area calculated | required using "powder specific surface area measuring apparatus SS-100" (made by Shimadzu Corporation). When the degree of sphericity of the silica particles is less than 0.6, the effect of improving the 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 narrow particle size distribution can be mentioned as a feature of the silica particles produced by the sol-gel method. Thereby, a further spacer effect can be exhibited in a two-component developer.

  As a method of producing spherical silica particles, known methods can be used, but spherical silica is produced mainly through, for example, three steps of hydrolysis, condensation polymerization, hydrophobization treatment, and if necessary, drying etc. The steps may be implemented in combination.

  The 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), and specifically, for example, the following procedure may be mentioned.

(1) Ammonia is used as a catalyst, and an alkoxysilane compound such as tetramethoxysilane or tetraethoxysilane is added dropwise to a mixed solvent of water and an alcohol while applying temperature, and the reaction is carried out by stirring. An aqueous suspension of silica particles is thus formed:
(2) Silane coupling agents such as methyltrimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane and the like, an aqueous suspension of silica particles, hexamethyldisilazane (HMDS), methyltrimethoxysilane, isobutyltrimethoxy The surface of the silica particles is subjected to a hydrophobization treatment by sequentially adding a hydrophobization treatment agent such as silane:
(3) The solvent is removed from the hydrophobized silica sol, and drying is performed to obtain the target spherical silica.

  The volume average primary particle size of spherical silica produced by the sol-gel method controls the addition amount of compounds such as hydrocarbyloxysilane compound, ammonia, alcohol, water, etc. of raw materials at the time of hydrolysis, reaction temperature, stirring speed, feeding speed, etc. The desired particle size can be controlled by

(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 toner base particles, the toner base particles are appropriately coated to obtain sufficient spacer effect, and if it is 1.5 parts by weight or less, the toner base particles are removed This is a range in which 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 is not only titanium oxide having a predetermined average aspect ratio described above and spherical silica having a predetermined average particle diameter but also known inorganic fine particles and organic particles as other external additives. Fine particles, lubricants, etc. may be externally added. Other external additives may be used alone or in combination of two or more. As a result, it is possible to further improve the fluidity, the cleaning property, the chargeability and the like as the toner.

  Examples of the inorganic fine particles include, but are not particularly 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. Among them, 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 hydrophobization treatment, and a known surface treatment agent is used for the hydrophobization treatment. The surface treatment agent may be used alone or in combination of two or more. The specific surface treatment agent is the same as that used for the above-mentioned hydrophobization treatment of titanium oxide.

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

  The lubricant is used to further improve the cleaning property and transferability, and as the lubricant, for example, zinc of stearic acid, salts of aluminum, copper, magnesium, calcium and the like, zinc of oleic acid Salts of manganese, iron, copper, magnesium etc., salts of zinc of palmitic acid, salts of copper, magnesium, calcium etc., salts of linoleic acid zinc, calcium etc., salts of ricinoleic acid zinc, calcium etc. of higher fatty acids Metal salts are mentioned.

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

  Among these, from the viewpoint of uniformity of particle diameter, shape controllability, and easiness of core-shell structure formation, it is preferable to produce by the emulsion aggregation method. Hereinafter, the method for producing a toner by the emulsion aggregation method will be specifically described, but the invention is not limited thereto.

(Emulsification aggregation method)
In the emulsion aggregation method, a dispersion of fine particles of a binder resin dispersed by a surfactant or a dispersion stabilizer (hereinafter, also referred to as "resin fine particles") is mixed with a dispersion of colorant or the like, if necessary. By aggregating (aggregating) until the desired particle size of the toner is obtained by adding an aggregating agent, and subsequently or simultaneously with the aggregation (association), fusing between the resin fine particles is performed, and the toner is controlled by shape control. It is a method of forming base particles.

  Here, the resin fine particles may be composite particles formed of a plurality of layers having a configuration of 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 mini emulsion polymerization method, a phase inversion emulsification method, or the like, or can be produced by combining several production methods. When the resin fine particles contain an internal additive, it is preferable to use a mini-emulsion polymerization method among them.

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

  In addition, toner base particles having a core-shell structure can also be obtained by the emulsion aggregation method, and specifically, the toner base particles having a core-shell structure are, first, a binder resin fine particle for core particles and, if necessary The core particle is prepared by aggregating and fusing the colorant fine particle with the core particle, and then adding the binder resin fine particle for the shell layer to the dispersion of the core particle to bind the shell layer on the surface of the core particle. It can be obtained by aggregating and fusing resin fine particles to form a shell layer covering the surface of the core particle.

  When the toner is produced by the emulsion aggregation method, the method for producing the toner according to the preferred embodiment comprises the steps of preparing the crystalline resin fine particle dispersion, the styrene acrylic resin fine particle dispersion, and the colorant dispersion (hereinafter also referred to as preparation step ) (A) and a step of mixing the crystalline resin fine particle dispersion, the styrene acrylic resin dispersion, and the colorant dispersion, and aggregating and fusing them (hereinafter also referred to as aggregation / fusion step) (b), Step (c) of controlling the shape factor (roundness) for controlling the shape factor (roundness) of the toner, and filtering the toner base particles by filtration from the dispersion system of the toner base particles to remove the surfactant etc. The washing step (d), the drying step (e) of drying the toner base particles, and the external additive addition step (f) of adding the external additive to the toner base particles are included. Each step will be described in detail below.

(A) Preparation Step More specifically, the step (a) includes the following steps of preparing a crystalline resin fine particle dispersion, a styrene acrylic resin fine particle dispersion, and a colorant dispersion preparing step as required.

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

(A1) Crystalline Resin Fine Particle Dispersion Preparation Step The crystalline resin fine particle dispersion preparation step is to synthesize a crystalline resin, disperse the crystalline resin in the form of fine particles in an aqueous medium, and disperse the crystalline resin fine particles. Is a process of preparing

  Since the method for producing the crystalline resin (crystalline polyester resin etc.) is as described above, the details will be omitted.

  The crystalline resin fine particle dispersion is prepared, for example, by a method of dispersion treatment in an aqueous medium without using a solvent, or by dissolving a crystalline resin in a solvent such as ethyl acetate to make a solution, and using the disperser to obtain the solution. After emulsifying and dispersing in an aqueous medium, there may be mentioned a method of removing the solvent.

  As a method of dispersing the crystalline resin in the aqueous medium, the resin is dissolved or dispersed in an organic solvent (solvent) to prepare an oil phase liquid, and the oil phase liquid is subjected to phase inversion emulsification or the like in the aqueous medium. After dispersing to form oil droplets in a controlled state at a desired particle size, the organic solvent may be removed.

  The above aqueous medium refers to one containing at least 50% by mass or more of water, and examples of components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, Methyl ethyl ketone, dimethylformamide, methyl cellosolve, tetrahydrofuran and the like can be mentioned. Among these, it is preferable to use an alcohol-based organic solvent such as methanol, ethanol, isopropanol or butanol, which is an organic solvent which does not dissolve the resin. Preferably, only water is used as the aqueous medium.

  In addition, when the crystalline polyester resin unit as a crystalline resin contains a carboxyl group, the carboxyl group contained in the unit is ion-dissociated to stably emulsify in the aqueous phase to promote the emulsification smoothly. Sodium oxide or the like may be added.

  As the organic solvent (solvent) used for the preparation of the above-mentioned oil phase liquid, one having a low boiling point and a low solubility in water is preferable from the viewpoint of easy removal processing after formation of oil droplets, Specifically, for example, methyl acetate, ethyl acetate, methyl ethyl ketone, isopropyl alcohol, methyl isobutyl ketone, toluene, xylene and the like can be mentioned. These can be used singly or in combination of two or more.

  The amount of the organic solvent (solvent) used (the total amount used when two or more are used) is usually 1 to 300 parts by mass, preferably 10 to 200 parts by mass, more preferably 25 with respect to 100 parts by mass of the resin. And 100 parts by mass. It is preferable at the point which can obtain the dispersion liquid of the resin fine particle with uniform particle size distribution as it is such a range.

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

  The use amount of the aqueous medium 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 setting the amount of the aqueous medium to be in the above range, the oil phase liquid can be emulsified and dispersed to a desired particle size in the aqueous medium. The aqueous medium used herein 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 water-soluble organic solvents include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone and tetrahydrofuran, and alcohol-based organic solvents which do not dissolve crystalline resin (for example, crystalline polyester resin) fine particles can be used. preferable. Moreover, in the aqueous medium, an amine or ammonia may be dissolved, as necessary.

  In the aqueous medium, a dispersion stabilizer may be dissolved, and in order to improve the dispersion stability of the oil droplets, an appropriate amount of surfactant, resin fine particles, etc. may be added.

  As a dispersion stabilizer, a well-known thing can be used, For example, inorganic compounds, such as a tricalcium phosphate, a calcium carbonate, a titanium oxide, colloidal silica, a hydroxyapatite, can be mentioned. Since it is necessary to remove the dispersion stabilizer from the toner base particles obtained, it is preferable to use one that is soluble in acid or alkali such as tricalcium phosphate, and from the environmental point of view It is preferable to use a degradable one.

  As the surfactant, anionic surfactants such as alkyl benzene sulfonate, α-olefin sulfonate, phosphate ester, sodium polyoxyethylene lauryl ether sulfate, sodium alkyl diphenyl ether disulfonate, alkyl amine salt, amino alcohol fatty acid Derivatives, polyamine fatty acid derivatives, amine salts such as imidazoline, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, quaternary ammonium salts such as benzethonium chloride Cationic surfactants, fatty acid amide derivatives, nonionic surfactants such as polyhydric alcohol derivatives, alanine, dodecyldi (aminoethyl) glycine, di (octyl) Minoethyl) amphoteric surfactants such as glycine and N-alkyl-N, N-dimethyl ammonium betaine, etc. may be mentioned, and anionic surfactants and cationic surfactants having a fluoroalkyl group can also be used. .

  Moreover, as resin fine particles for the improvement of dispersion stability, polymethyl methacrylate resin fine particles, polystyrene resin fine particles, polystyrene-acrylonitrile resin fine particles, etc. may be mentioned.

  Such emulsification and dispersion of the oil phase liquid (the above dispersion process) can be carried out by utilizing mechanical energy, and the dispersion machine for carrying out the emulsification and dispersion is not particularly limited, and a low speed shear type may be used. Dispersion machines, high-speed shear type dispersers, friction type dispersers, high pressure jet type dispersers, ultrasonic dispersers such as ultrasonic homogenizers, high pressure impact type disperser Ultimizer, etc. may be mentioned.

  At the time of dispersion, 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 oil droplets was carried out by gradually raising the temperature of the entire dispersion in a state in which the crystalline resin fine particles were dispersed in the aqueous medium while stirring, and giving strong stirring in a certain temperature range After that, it can be performed by an operation such as desolvation. Alternatively, it can be removed while reducing pressure using an apparatus such as an evaporator.

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

  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 process Styrene acrylic resin fine particle dispersion preparation process as amorphous resin synthesizes a styrene acrylic resin, and disperses this styrene acrylic resin in an aqueous medium into fine particles to obtain styrene This is a step of preparing a dispersion of acrylic resin fine particles.

  Since the method for producing the styrene acrylic resin is as described above, the details will be omitted.

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

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

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

  In addition, a chain transfer agent generally used can be used in the seed polymerization reaction system for obtaining the styrene acrylic resin fine particles for the purpose of adjusting the molecular weight of the amorphous resin. As chain transfer agents, mercaptans such as octyl mercaptan, dodecyl mercaptan and t-dodecyl mercaptan; mercapto propionic acids such as n-octyl 3-mercapto propionate and stearyl 3-mercapto propionate; and styrene dimer etc. It can be used. These can be used singly 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, the boiling point is low and water is also similar to the above, from the viewpoint of easy removal treatment after formation of oil droplets. Those having low solubility in water are preferable, and specific examples thereof include methyl acetate, ethyl acetate, methyl ethyl ketone, isopropyl alcohol, methyl isobutyl ketone, toluene, xylene and the like. These can be used singly or in combination of two or more.

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

  The use amount of the aqueous medium 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 setting the amount of the aqueous medium to be in the above range, the oil phase liquid can be emulsified and dispersed to a desired particle size in the aqueous medium.

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

  The emulsification and dispersion of such an oil phase liquid can be performed using mechanical energy in the same manner as described above, and the dispersing machine for performing the emulsification and dispersion is not particularly limited, and the above (a1 The one described in the above can be used.

  The removal of the organic solvent after the formation of oil droplets was carried out by gradually raising the temperature of the whole dispersion in a state where the styrene acrylic resin fine particles were dispersed in the aqueous medium while stirring, and giving strong stirring in a certain temperature range After that, it can be carried out by an operation such as desolvation. Alternatively, it can be removed while reducing 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 above method (I) or (II) is preferably 60 to 1000 nm in terms of volume based median diameter, 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 size of the oil droplets can be controlled by the magnitude of mechanical energy at the time of emulsification and dispersion.

  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 Particle Dispersion Preparation Step This colorant particle dispersion preparation step is a step of dispersing a colorant (pigment) in an aqueous medium in the form of microparticles to prepare a dispersion of colorant microparticles.

  The aqueous medium may be the same as the aqueous medium used for dispersing the crystalline resin in the step (a1). In the aqueous medium, a surfactant, fine resin particles, etc. may be added for the purpose of improving the dispersion stability. The surfactant and the resin fine particles are also as described in the above step (a1).

  Dispersion of the colorant can be carried out using mechanical energy, and such a disperser is not particularly limited, and the above-mentioned dispersers can be used.

  The volume average particle size 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.

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

(A4) Releasing agent fine particle dispersion preparing step This releasing agent fine particle dispersion preparing step is carried out as required, and the releasing agent is dispersed in the form of fine particles in an aqueous medium to disperse the releasing agent fine particles Is a process of preparing

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

  Dispersion of the mold release agent can be carried out using mechanical energy, and such a disperser is not particularly limited, and as mentioned above, low speed shear type disperser, high speed shear Examples of the disperser include a friction disperser, a friction disperser, a high pressure jet disperser, an ultrasonic disperser such as an ultrasonic homogenizer, a high pressure impact disperser Ultimizer, or a high pressure homogenizer. In dispersing the release agent fine particles, heating may be performed as necessary.

(B) Coagulation / fusion process This aggregation / fusion process comprises a crystalline resin fine particle dispersion, a styrene acrylic resin fine particle dispersion, and optionally, a colorant fine particle dispersion, and if necessary, a release agent fine particle dispersion And other ingredients are added and mixed, and the particles are slowly aggregated while balancing the repulsive force of the fine particle surface by pH adjustment and the cohesion by the addition of the aggregating agent consisting of the electrolyte body, average particle diameter and particle size distribution This is a step of forming toner base particles by performing fusion while controlling heat and stirring at the same time as performing aggregation while controlling and performing shape control. This aggregation / fusion process can also be performed using mechanical energy or heating means as required.

(B1) Flocculation step In the flocculation step, first, the obtained dispersions and surfactants are mixed to form a mixture, and the mixture is heated to a temperature above the glass transition temperature of the styrene acrylic resin as the amorphous resin to aggregate. To form agglomerated particles. It is preferable to adjust the pH of a liquid mixture to the range of 8-12 under stirring, and, as for formation of aggregate particle, it is more preferable to make it the range of 9-11. Such a range is preferable in that aggregation 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, a salt containing a Group 2 element, etc. as a coagulant to the above mixed solution, the aggregation is heated by heating at a temperature higher than the glass transition temperature of a styrene acrylic resin as an amorphous resin. Proceed to form agglomerated particles (simultaneously, agglomerated particles may be fused).

  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 liquid, and the coagulant is By the addition, the crystalline resin microparticles, the styrene acrylic resin microparticles, and the colorant microparticles are aggregated (the particles may be fused at the same time). Then, when the size of the aggregated particles reaches a target size, a salt such as saline is added to stop aggregation.

  The aggregating agent used in the present invention is not particularly limited, but one selected from metal salts is suitably used. For example, salts of monovalent metals such as salts of alkali metals 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, manganese sulfate and the like, and among them, Preferred are salts of divalent metals. With the use of divalent metal salts, aggregation can be promoted with smaller amounts. You may use these 1 type or in combination of 2 or more types.

  In the aggregation step, it is preferable to minimize the standing time (time to start heating) to be left after addition of the coagulant as much as possible. Thus, it is preferable to start heating the dispersion liquid for aggregation as quickly as possible after addition of the aggregating agent and to bring it to a temperature above the glass transition temperature of the styrene acrylic resin. The reason for this is not clear, but the aggregation state of the particles may change with the lapse of the standing time, and the particle size distribution of the obtained toner particles may become unstable or the surface properties may fluctuate. It is because there is. The standing time is usually within 30 minutes, preferably within 10 minutes. The temperature at which the coagulant is added is not particularly limited, but is preferably equal to or less than the glass transition temperature of the amorphous resin in the binder resin. That is, after adding a coagulant | flocculant, it is preferable to make it heat up rapidly by heating, and it is preferable to make a temperature rising rate into 0.8 degrees C / min or more. The upper limit of the temperature raising 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 the progress of rapid fusion. Furthermore, after the dispersion liquid for aggregation reaches a temperature higher than the glass transition temperature of the amorphous resin, the temperature of the dispersion liquid for aggregation is fixed for a certain period of time, preferably 4.5 to 7.0 μm on a volume basis median diameter. It is important to continue fusion bonding by holding until it becomes (the first aging step). In addition, it is preferable to measure the shape factor (roundness) of the particles during ripening, and preferably to perform the first ripening step until it is 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 toner particles finally obtained can be improved.

  When a binder resin having a core-shell structure is to be obtained, an aqueous dispersion of a resin (preferably, the above-mentioned styrene acrylic resin) forming the shell layer is further added in the above-mentioned first ripening step, and the above The resin forming the shell layer is aggregated and fused on the surface of the binder resin particle (core particle) of the single layer structure obtained in the above. Thereby, a binder resin having a core-shell structure is obtained (shelling process). At this time, following the shelling step, it is preferable to further heat-process the reaction system until the aggregation and fusion of the shell on the core particle surface are strengthened and the particle shape becomes a desired shape (second Maturation 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 above-mentioned range of the average circularity.

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

  In the case of aggregation, it is preferable to heat and raise the temperature. Under the present circumstances, when it becomes more than fusion | melting temperature by heating and temperature rising, a fusion | melting process will also advance simultaneously. As a temperature rising rate, it is preferable to carry out in the range of 0.1-5 degrees C / min. Such a range is preferable in that aggregation with a sharp particle size distribution is possible. Moreover, it is preferable to carry out heating temperature (peak temperature) in the range of 40-100 degreeC. Such a range is preferable in that aggregation with a sharp particle size distribution is possible.

(B2) Agglomeration stopping step The aggregation particles are measured, for example, with a Coulter counter etc., and when the desired average particle diameter is obtained, an aggregation terminator is added to stop particle growth. After that, the liquid containing the aggregated particles may be continuously heated and stirred as necessary.

  As an aggregation stopper, 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, N diacetic acid), humic acid and fulvic acid, maltol and ethylmaltol, pentaacetic acid and tetraacetic acid, known water-soluble polymers having both carboxyl and hydroxyl functional groups (polyelectrolytes), hydroxylated Sodium, potassium hydroxide, sodium chloride or aqueous solutions of these may be mentioned. In the aggregation stopping step, stirring may be performed according to the aggregation step.

(B3) Fusion Step The fusion step is carried out by heating the reaction system to a desired fusion temperature after passing through the aggregation termination step (b2) or simultaneously with the aggregation step (b1). This is a step of fusing each of the constituting fine particles and fusing the aggregated particles to form fused particles.

  The fusion temperature in this fusion step is preferably equal to or higher than the melting point of the crystalline resin, and is preferably 0 to 20 ° C. higher than the melting point of the crystalline resin. As a time of heating, it may be performed to such an extent that it is fused, 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 Ltd.), a desired shape factor (for example, about 0.96) can be obtained. You can do it until it reaches.

  In the aggregation / fusion step, a surfactant may be added to the aqueous medium in order to stably disperse the particles in the aggregation system.

  After the (aggregation) coalescence, the dispersion liquid of the toner base particles can be cooled to obtain coalesced particles. However, when the toner is obtained by the emulsion aggregation method, after the aggregation and fusion steps, before cooling, it will be described later. It is preferable to further have a circularity control step (c) of

  The cooling rate is preferably 0.2 to 20 ° C./min, more preferably 2 to 20 ° C./min. Within such a range, it is preferable in that the toner surface after cooling is smooth. It does not specifically limit as a cooling method, The method of introduce | transducing and cooling a refrigerant | coolant from the exterior of a reaction container, and the method of injecting | throwing-in cold water directly to a reaction system and cooling can be illustrated.

(C) Step of Controlling Shape Factor (Circularity) When toner is obtained by the emulsion aggregation method, it is preferable to have a step of controlling the shape coefficient (circularity) after the above aggregation / fusion step. Specifically as a control process of a shape factor (roundness), the heat processing which heats the particle | grains obtained by the aggregation and the melt | fusion process is mentioned. The shape factor (roundness) can be controlled by heating temperature and holding time. The shape factor (roundness) can be made close to 1 by raising the heating temperature or prolonging the holding time. However, in order to prevent the occurrence of reaggregation of the toner base particles, it is preferable that the heating temperature is not excessively high. In addition, for the same reason, it is preferable not to make the holding time excessively long.

  The heating temperature in the control process of the shape factor (roundness) is preferably 70 to 95 ° C., and more preferably 70 to 90 ° C., from the viewpoint of bringing the shape factor (roundness) close to one. Further, the holding time at the heating temperature is not particularly limited, and may be performed until the shape factor (degree of circularity) reaches a target value (numerical value close to 1). Control of the shape factor (circularity) is performed by measuring the circularity of a particle diameter of 2 μm or more in volume median diameter with a measuring device of the shape factor (circularity) during heating, and it is desired circularity Control is possible by judging as appropriate. The volume median diameter is a volume-based median diameter (volume-based median diameter) measured by a precise particle size distribution measuring apparatus (for example, "Multisizer 3" manufactured by Beckman Coulter, etc.) adopting 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 extracted from the cooled dispersion of toner base particles. A filtration process in which toner base particles are separated by solid-liquid separation to separate toner base particles by filtration, and a washing process in which attached substances such as surfactants are removed from the filtered toner base particles (cake-like aggregate) And will be applied. Specific solid-liquid separation and washing methods include centrifugal separation, vacuum filtration using an aspirator, Nutsche, filtration using a filter press, etc., and these are not particularly limited. . In the filtration / washing step, pH adjustment or pulverization may be appropriately performed. Such an operation may be repeated. Adherents such as surfactant and coagulant are removed from the toner base particles separated by filtration. In the washing process, the washing (water washing) process is performed until the electric conductivity of the filtrate is, for example, 5 to 10 μS / cm level.

(E) Drying Step In this drying step, the washed toner base particles are subjected to a drying treatment. As a dryer used in this drying process, an oven, a spray dryer, a vacuum freeze dryer, a vacuum dryer, a stationary shelf dryer, a movable shelf dryer, a fluidized bed dryer, a rotary dryer, a stirring type A dryer etc. are mentioned and these are not specifically limited. The water content of the dried toner particles (toner base particles) measured by Karl Fischer coulometric titration is preferably 5% by mass or less, and more preferably 2% by mass or less.

  Further, in the case where the toner base particles subjected to the drying process are aggregated by a weak interparticle attraction to form an aggregate, the aggregate may be crushed. Here, mechanical disintegrators such as jet mills, comills, Henschel mixers, coffee mills and food processors can be used as the disintegrator.

(Volume average particle diameter of toner base particles)
The particle diameter of the toner base particles is preferably small in order to improve the image quality, but the toner base particles have a volume average particle diameter in the range of 2 to 8 μm to achieve both chargeability and flowability. It is preferable from the viewpoint. As a result, development, transfer and cleaning do not become difficult, which is preferable. The toner base particles preferably have a particle size in the range of 4 to 7 μm from the above viewpoint.

(Average circularity of toner mother particles)
In the toner for electrostatic image development of the present invention, the average circularity of toner base particles represented by the following formula 1 is preferably 0.92 to 1.000 from the viewpoint of improvement of transfer efficiency.

(Equation 1) Average circularity = (peripheral length of a circle having the same projected area as the particle image) / (peripheral length of particle projection image)
As an example of measurement which asks for the above-mentioned average circularity, measurement using a measuring device "FPIA-2100" (made by Sysmex) of average circularity is mentioned. As a specific operation, after toner base particles are wetted with a surfactant aqueous solution and subjected to ultrasonic dispersion for 1 minute and dispersed, using “FPIA-2100” in measurement condition HPF (high magnification imaging) mode, Measurement is performed with the appropriate concentration of 3000 to 10000 HPF detections.

(F) External Additive Addition Step In this external additive addition step, the charge control agent and various inorganic substances are added to the surface of the dried toner base particles for the purpose of improving the flowability and chargeability and improving the cleaning ability. This is a step of adding an external additive such as fine particles, organic fine particles, or a lubricant. As an apparatus used for adding an external additive, various known mixing apparatuses, such as a turbular mixer, a Henschel mixer, a Nauta mixer, a V-type mixer, a sample mill, can be mentioned. In addition, in order to set the particle size distribution of the toner in an appropriate range, sieve classification may be performed as necessary.

<Developer>
For example, when the toner as described above contains a magnetic substance and is used as a one-component magnetic toner, when it is mixed with so-called carrier particles and used as a two-component developer, the nonmagnetic toner is used alone, etc. Any of these can be used suitably. In particular, it is preferable to use as a two-component developer including the toner and carrier particles.

  The two-component developer is prepared by appropriately mixing toner particles and carrier particles such that the content (toner concentration) of toner particles is 4.0 to 8.0% by mass. Can be configured. Examples of mixing devices used for the mixing include Nauta mixers, W-cone and V-type mixers.

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

  As the carrier, it is preferable to use one further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a 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 or a fluorine resin is used. The resin for forming the resin dispersion type carrier is not particularly limited, and any known resin can be used. For example, acrylic resin, styrene-acrylic resin, polyester resin, fluorine resin, phenol resin, etc. may be used. can do.

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

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. Although the display of "part" or "%" may be used in an Example, unless otherwise indicated, it represents "mass part" or "mass%." Also, unless otherwise stated, each operation is performed at room temperature (25 ° C.).

[Preparation of spherical silica]
[Preparation of spherical silica 1]
(1) To a 3 L reactor equipped with a stirrer, a dropping funnel, and a thermometer, 630 parts by mass of methanol and 90 parts by mass of 10% ammonia water were added and mixed. To this solution, 900 parts by mass of tetramethoxysilane was added, and the tetramethoxysilane was hydrolyzed while stirring to obtain a suspension of silica particles. The mixture was then heated to 60 to 70 ° C. and 390 parts of methanol was distilled off to obtain an aqueous suspension of silica particles.

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

  (3) After 1200 parts by mass of methyl isobutyl ketone was added to the dispersion thus obtained, the mixture was heated to 80 ° C. to distill off methanol and water. 250 parts by mass of hexamethyldisilazane was added to the obtained dispersion at room temperature, and the mixture was heated to 120 ° C. and reacted for 3 hours to trimethylsilylate 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 to 5]
The number average particle diameter is adjusted by changing the concentration of the reactant in the system by adjusting the number of added mass parts of tetramethoxysilane and hexamethyldisilazane in the preparation of the spherical silica 1 to adjust the number average particle diameter as shown in Table 1. Spherical silicas 2 to 5 were prepared. When the concentration of the reactant is increased, the number average particle diameter of spherical silica formed is increased, and when the concentration is decreased, the number average particle diameter of spherical silica obtained is decreased. The degree of sphericity of spherical silicas 2 to 5 was all 0.6 or more.

[Preparation of titanium oxide]
The titanium oxide was manufactured in the following procedure, with reference to the description of Japanese Patent Application Laid-Open No. 2004-315356.

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

  (2) The obtained amorphous titanium oxide was heated in the atmosphere at 800 ° C. for 5 hours in a high temperature electric furnace 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 above-mentioned stirrer, dropping funnel and thermometer, and the mixture is added for 10 hours in 2 L of toluene The mixture was stirred and hydrophobized. Thereafter, the reaction product is centrifuged to wash the reaction solvent, and then it is again centrifuged and collected, 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 preparation of the titanium oxide 1, titanium oxide particles 2 to 5 shown in Table 2 were prepared by changing the stirring reaction time to adjust the number average minor axis and the number average major axis, and hence the average aspect ratio.

[Preparation 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) in the solution. Was gradually added. Subsequently, the colorant fine particle dispersion having a volume-based median diameter of 126 nm is performed by performing dispersion processing using a stirring apparatus "CLEARMIX (registered trademark) W motion CLM-0.8" (manufactured by M. Technics Co., Ltd.) Liquid [1] was prepared.

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

(Second stage polymerization)
A solution of 2 parts by mass of sodium polyoxyethylene (2) sodium dodecyl ether sulfate in 3000 parts by mass of ion-exchanged water is charged in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introducing device. After heating, 42 parts by mass (in terms of solid content) of the resin fine particle [1] prepared above, 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-octylmercaptan A solution dissolved at 80 ° C. in a monomer solution consisting of 3 parts by mass is added to the circulation route A dispersion liquid containing emulsified particles (oil droplets) was prepared by mixing and dispersing for 1 hour with a mechanical disperser "CLEARMIX (registered trademark)" (manufactured by M. Technics Co., Ltd.).

  Then, 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 the system is heated and stirred at 80 ° C. for 1 hour to carry out polymerization. A dispersion of resin fine particles [2] was prepared.

(Third stage polymerization)
A solution in which 10 parts by mass of potassium persulfate is dissolved in 200 parts by mass of ion-exchanged water is further added to the dispersion of resin fine particles [2] prepared above, and a temperature condition of 80 ° C.
Styrene 380 parts by mass n-butyl acrylate 132 parts by mass Methacrylic acid 39 parts by mass n-octylmercaptan 6 parts by mass A monomer mixed solution consisting of 6 parts by mass was dropped over 1 hour. After completion of the dropwise addition, polymerization was carried out by heating and stirring for 2 hours, and then the dispersion was 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 particle 1)
As a material of a 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 placed in a reaction vessel equipped with a nitrogen inlet 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, and the temperature was raised to 210 ° C., and the reaction was carried out for 8 hours. The reaction was further performed at 8.3 kPa for 1 hour to obtain a crystalline resin 1.

  A DSC curve of the obtained crystalline resin 1 was obtained using a differential scanning calorimeter “Diamond DSC” (manufactured by Perkin Elmer) under the conditions of a temperature rising rate of 10 ° C./min. The measurement result of the melting point (Tm) by the method of measuring the endothermic peak top temperature is 82.8 ° C., and as a result of measuring the molecular weight by GPC “HLC-8120GPC” (manufactured by Tosoh Corp.), Mw in terms of standard polystyrene Was 28,000.

(Preparation of Crystalline Resin Fine Particle Dispersion 1)
100 parts by mass of the crystalline resin 1 was dissolved in 400 parts by mass of ethyl acetate. Next, 25 parts by mass of a 5.0% by mass aqueous solution of sodium hydroxide was added to prepare a resin solution. This resin solution was introduced into a container having a stirrer, and while the resin solution was being stirred, 638 parts by mass of a 0.26% by mass aqueous solution of sodium dodecyl sulfate was dropwise added and mixed over 30 minutes. During the dropping of the sodium dodecyl sulfate aqueous solution, the liquid in the reaction container became cloudy, and further, after the entire amount of the sodium dodecyl sulfate aqueous solution was dropped, an emulsion liquid in which resin fine particles were uniformly dispersed was prepared. Next, the above emulsion is heated to 40 ° C., and ethyl acetate is distilled off under a reduced pressure of 150 hPa using a diaphragm type vacuum pump “V-700” (manufactured by BUCHI) to obtain a crystalline polyester resin Thus obtained 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 composed of hybrid resin)
220 parts by mass of sebacic acid (molecular weight 202.25) as a 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 a polyhydric alcohol compound In a reaction vessel equipped with a nitrogen inlet tube, a dehydration tube, a stirrer and a thermocouple, the mixture was heated to 160 ° C. to dissolve. 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 a bireactive monomer, which are materials of a vinyl resin unit mixed in advance It dripped over 1 hour by the dropping funnel. Stirring is continued for 1 hour while maintaining at 170 ° C. to polymerize 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 The reaction mixture was heated to 210.degree. C. and reacted for 8 hours. The reaction was further performed at 8.3 kPa for 1 hour to obtain a crystalline resin 2 composed of a hybrid crystalline polyester resin.

(Preparation of Crystalline Resin Fine Particle Dispersion 2)
100 parts by mass of the crystalline resin 2 was dissolved in 400 parts by mass of ethyl acetate. Next, 25 parts by mass of a 5.0% by mass aqueous solution of sodium hydroxide was added to prepare a crystalline resin solution. The crystalline resin solution was added to a container having a stirring device, and while being stirred, 638 parts by mass of a 0.26% by mass aqueous solution of sodium dodecyl sulfate was added dropwise over 30 minutes. During the dropping of the sodium dodecyl sulfate aqueous solution, the liquid in the reaction container became cloudy, and further, after the entire amount of the sodium dodecyl sulfate aqueous solution was dropped, an emulsion liquid in which the crystalline resin fine particles were uniformly dispersed was prepared. Then, the above-mentioned emulsion is heated to 40 ° C., and hybrid crystalline polyester resin is obtained by distilling out ethyl acetate under a reduced pressure of 150 hPa using a diaphragm type vacuum pump “V-700” (manufactured by BUCHI). Crystalline resin fine particle dispersion 2 was obtained.

[Production of Toner Base Particle 1]
(Aggregation and fusion process)
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device, 300 parts by mass (solid content conversion) of the styrene acrylic resin fine particle dispersion 1 and 60 parts by mass of the crystalline resin fine particle dispersion 1 (solid) Minute), 1100 parts by mass of ion-exchanged water, and 40 parts by mass (in terms of solid content) of the colorant particle dispersion [1], and after adjusting the liquid temperature to 30 ° C., prepare a 5N aqueous solution of sodium hydroxide In addition, the pH was adjusted to 10. Then, an aqueous solution in which 60 parts by mass of magnesium chloride was dissolved in 60 parts by mass of ion exchange water was added over 10 minutes at 30 ° C. while stirring. After holding for 3 minutes, the temperature rising was started, and the system was heated up to 85 ° C. over 60 minutes, aggregated while maintaining 85 ° C., and the particle growth reaction was continued. In this state, the particle size of the aggregated particles is measured by "Coulter Multisizer 3" (manufactured by Beckman Coulter, Inc.), and 40 parts by mass of sodium chloride is ion-exchanged water when the volume-based median diameter reaches 6 μm. An aqueous solution dissolved in 160 parts by mass is added to stop particle growth, and further, heat fusion is carried out by heating and stirring at a liquid temperature of 80 ° C. as a ripening step to promote fusion between particles, and a measurement device of average circularity “FPIA After confirming that the average circularity was 0.920 or more with “-2100” (manufactured by Sysmex Corporation), the dispersion was cooled to 30 ° C. to prepare a dispersion of toner mother particles 1.

(Washing and drying process)
The resulting dispersion liquid of toner mother particles 1 was subjected to solid-liquid separation with a basket type centrifuge "MARK III Model No. 60 × 40 + M" (manufactured by Matsumoto Machinery Co., Ltd.) to form a wet cake of toner mother particles. The wet cake is washed with ion-exchanged water at 40 ° C. until the electric conductivity of the filtrate reaches 5 μS / cm in the basket type centrifuge, and then transferred to a “flash jet dryer” (manufactured by Seishin Co., Ltd.) The toner base particles 1 were produced by drying until the water content became 0.5% by mass.

(Method of calculating content of constituent resin in toner base particle)
The content (% by mass) of the crystalline resin in the toner base particles is calculated by the following equation. In addition, content (mass%) is defined from the mass of the material thrown in in 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 (% by mass) of the styrene acrylic resin in the toner base particles is calculated by the following equation. The mass of each material is a value converted to 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 particle 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 particle 1 is determined 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]
Similar to the preparation of toner base particle 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 particle become the values shown in Table 3. , Toner base particles 2 to 4 were produced. The crystalline resins contained in the toner base particles 3 are all hybrid crystalline polyester resins, 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 particle 1 (100 parts by mass) prepared above, and added to the Henschel mixer type "FM 20 C / I" (manufactured by Nippon Coke Kogyo Co., Ltd.) The rotation number of the stirring blade was set so as to be 40 m / s, and stirring was performed for 20 minutes, whereby Toner 1 was produced. The temperature of the mixed powder at the time of external additive mixing was set to be 40 ± 1 ° C.

・ Titanium oxide 3 0.2 parts by mass ・ Spherical silica 2 1.0 parts by mass [Preparation of Toners 2 to 28]
In preparation of Toner 1, the amount of crystalline resin (crystalline polyester resin) and the amount of styrene acrylic resin in preparation 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 The same procedure as described above was repeated except that toners 2 to 28 were produced.

[Preparation of developers 1 to 28]
A ferrite carrier having a volume average particle diameter of 60 μm was added to the toners 1 to 28 prepared above so that the toner content (toner concentration) in the two-component developer became 7% by mass. Thereafter, they were mixed for 30 minutes in a V-type mixer to obtain corresponding two-component developers 1 to 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 Nippon Denshi Co., Ltd.), the particle sizes of titanium oxide and spherical silica are measured, and an average value of n = 20 is determined to obtain a number average. It was the particle size. In the case of titanium oxide, the major diameter (the largest diameter in the case of a spherical shape) and the minor diameter (the smallest diameter in the case of a spherical shape) were respectively measured. Similarly, with regard to the major axis and the minor axis, mean values of n = 20 were respectively obtained to obtain a number average major axis and a number average minor axis.

<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, and this was used as the average aspect ratio.

<Method for measuring melting point of crystalline polyester resin>
The melting point of the crystalline polyester resin was measured by a differential scanning calorimeter (DSC). Specifically, using a differential scanning calorimeter "Diamond DSC" (manufactured by PerkinElmer Co., Ltd.), the first heating process of raising the temperature from 0 ° C to 200 ° C at a lifting rate of 10 ° C / min, the cooling rate 10 ° C / min Measured under the measurement conditions (temperature rise and cooling conditions) that sequentially undergo a cooling process of cooling from 200 ° C. to 0 ° C. and a second heating process of raising the temperature from 0 ° C. to 200 ° C. at an elevation 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 enclosed in an aluminum pan and set in a sample holder of "diamond DSC". The reference used an empty aluminum pan.

[Evaluation]
A commercially available digital full color multifunction device "bizhub PRO C6500" (manufactured by Konica Minolta Co., Ltd., "bizhub" is a registered trademark of the company) was used as an evaluation device.

[Evaluation 1: Low temperature fixability]
In a copying machine "bizhub PRO C6500" (manufactured by Konica Minolta Co., Ltd.), a fixing device was modified to prepare one capable of changing the surface temperature of the heat roller for fixing in a range of 100 to 210 ° C. Each of the above developers 1 to 28 was loaded to this. Fixing experiment to fix a solid image of toner adhesion amount 11 mg / 10 cm ² on A4 size plain paper (basis weight 80 g / m ² ) changed to increase fixing temperature set from 140 ° C. by 1 ° C. Repeatedly performed up to 200.degree. Among fixing experiments in which no image contamination due to low temperature offset is visually observed, the fixing temperature in the fixing experiment related to the lowest fixing temperature was evaluated as the minimum fixing temperature. The lower the minimum fixing temperature, the better the low-temperature fixability, and if it is less than 160 ° C., it is judged as a pass with no problem in practical use.

-Evaluation criteria-
◎: minimum fixing temperature is less than 155 ° C.,
○: The minimum fixing temperature is 155 ° C. or more and less than 160 ° C.
X: The minimum fixing temperature is 160 ° C. or more.

[Evaluation 2: Charge amount stability (environmental difference and durability stability)]
A copying machine “bizhub PRO C6500” (Konica Minolta Co., Ltd.) as a test image on A4 high quality paper (65 g / m ² ) under normal temperature and humidity (temperature 20 ° C., humidity 50% RH) environmental conditions Five sheets of printing for forming a belt-like solid image having a printing rate of 5% were printed, and the charge amount of the toner at that time was measured. Similarly, even under high-temperature, high-humidity (30 ° C., 80% RH) environmental conditions, a print is formed that forms a belt-shaped solid image with a coverage of 5% as a test image on A4 size wood free paper (65 g / m ² ). The amount of charge of the toner after 10,000 sheets printing and after printing five sheets and after printing 100,000 sheets was measured and evaluated according to the following evaluation criteria. The charge amount was measured by sampling a two-component developer in the developing device and using a blow-off charge amount measuring apparatus “TB-200” (manufactured by Toshiba Chemical Co., Ltd.). The smaller the difference Δ (hereinafter referred to as the environmental difference Δ) between the charge amount of toner when printing on a 5-sheet under normal temperature normal humidity environment and high temperature high humidity environment, the less the influence of the external environment, the more stable the toner charge amount If it is less than 10 μC / g, it is judged as a pass with no problem in practical use. In addition, the smaller the difference Δ (hereinafter referred to as the durability reduction value Δ) between the charge amount of toner after printing on 5 sheets and printing on 100,000 sheets under 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 a pass with no problem in practical use.

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

(Durability decrease value Δ)
:: The endurance drop value Δ of the charge amount of toner is less than 5 μC / g after printing 5 sheets and after printing 100,000 sheets under a high temperature and high humidity environment.
Good: The endurance drop value Δ of the charge amount of toner is 5 μC / g or more and less than 10 μC / g after printing 5 sheets and printing 100,000 sheets under a high temperature and high humidity environment.
X: The endurance drop value Δ of the charge amount of toner is 10 μC / g or more in the high temperature and high humidity environment after printing of 5 sheets and after printing of 100,000 sheets.

[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 A4 high quality paper (65 g / m ² ) under high temperature and high humidity (30 ° C., 80% RH) environmental conditions % Printing is performed to form a belt-like solid image, and a gradation pattern of 32 gradation levels is output after printing five sheets and after printing 100,000 sheets, and the graininess of this gradation pattern is evaluated based on the following evaluation criteria Therefore, it evaluated. Granularity evaluation is performed by performing Fourier transform processing in consideration of MTF (Modulation Transfer Function) correction to the readout value of a gradation pattern by CCD, and measuring GI value (Graininess Index) according to human relative luminosity, and maximum The GI value was determined. The smaller the GI value, the better, and if the fluctuation value Δ is less than 0.020, it is judged as a pass with no problem in practical use. This GI value is a value published in the Journal of the Imaging Society of Japan 39 (2), 84. 93 (2000).

-Evaluation criteria-
:: GI temperature fluctuation value Δ is less than 0.010 after printing on 5 sheets and after printing on 100,000 sheets under a high temperature and high humidity environment.
:: GI temperature fluctuation value Δ of 0.010 or more and less than 0.020 after printing on 5 sheets and printing on 100,000 sheets under high temperature and high humidity environment
X: GI value fluctuation value Δ is 0.020 or more after printing on 5 sheets and after printing on 100,000 sheets under a high temperature and high humidity environment.

  The obtained results are shown in Table 4 below.

  From the results in Table 4 above, the toners of Examples 1 to 11 show a small decrease in the charge amount even under high temperature and high humidity, a small decrease in the charge amount even under high durability conditions, and also have low temperature fixability. And make the above performance compatible. On the other hand, in the toners of Comparative Examples 1 to 17, it was impossible to achieve all the above-mentioned performances. As described above, according to the present invention, it is possible to produce a toner capable of stably outputting an image regardless of the printing environment or the usage condition while low temperature fixing is possible.

  Among the toners of Examples 1 to 11, in 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, the content of the crystalline resin exceeds 30% by mass. The charge amount durability lowering value was smaller than that of the toner of Example 10. It is presumed 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 may not be too large.

  Further, in Example 11 in which the crystalline resin has a hybrid structure, superior results were shown in all evaluation items as compared with the other examples. This can prevent the phenomenon in which the crystalline polyester resin is localized on the surface of the toner base particle due to the difference in the affinity between the styrene acrylic resin and the crystalline polyester resin by hybridizing the crystalline polyester resin. It is thought that it is for. Since the polyester resin having a large number of hydroxyl groups structurally is not unevenly distributed on the surface, it is considered that the environmental stability and the durability stability are further improved because the influence of the external environment, in particular, the humidity is less.

Claims (6)

A toner for developing an electrostatic charge image comprising toner base particles comprising a styrene acrylic resin and a crystalline resin as a binder resin, and an external additive,
The external additive is titanium oxide whose average aspect ratio is 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 average particle diameter is larger than the number average minor axis of the titanium oxide and look containing a spherical silica which is a range 60 to 150 nm,
The content of the styrene acrylic resin is 70% by mass or more with respect to the total amount of the binder resin .   The toner for electrostatic charge image development according to claim 1, wherein the crystalline resin is a crystalline polyester resin. The toner for electrostatic image development according to claim 2 , 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 toner for developing an electrostatic charge image according to any one of claims 1 to 3, wherein a content of the crystalline resin in the toner base particles is 1 to 30% by mass.   The toner according to any one of claims 1 to 4, wherein the titanium oxide has a rutile crystal structure.   A two-component developer for electrostatic image development, comprising the toner for electrostatic image development according to any one of claims 1 to 5 and carrier particles.