JP2012163800A - Toner for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development which retains excellent low-temperature fixability and hot-offset resistance and obtains high picture quality for a long term with excellent durability.SOLUTION: A toner for electrostatic charge image development contains a binder resin, a release agent and a colorant, and a polyester resin and a block copolymer K are contained as the binder resin, in which the block copolymer K contains a polymerization block A by a styrene-based monomer and a polymerization block B by a conjugated diene monomer.

Description

  The present invention relates to an electrostatic charge image developing toner used in an electrophotographic image forming apparatus.

  In recent years, from the viewpoint of preventing global warming, energy saving has been studied in various fields, and the demand for energy saving technology is increasing in information devices such as image forming apparatuses. In order to save energy in information equipment, it is important to save energy in a fixing process in which a large amount of energy is used, and among them, toner low-temperature fixing technology is strongly demanded. On the other hand, in the production print market where high-speed printing equivalent to printing is required, high image quality equivalent to printing and good image storage are required, and it is necessary to balance these requirements with low-temperature fixability. It is expected to be increasingly demanded in the future.

  As a low-temperature fixing technique, it is known that it is effective to lower the glass transition temperature of the toner resin. However, if the glass transition temperature of the toner resin is lowered, offset occurs in the high temperature region or the blocking resistance is lowered. Therefore, it is possible to fix at a low temperature only by lowering the glass transition temperature. It is difficult to sufficiently function as a toner in characteristics.

  In this respect, polyester resins have a rigid molecular chain because of the ability to introduce a benzene ring into the main chain, and can be set to a lower molecular weight than styrene acrylic resins, which can lower the melt viscosity and lower temperature fixability. It is characterized by being excellent. However, by simply using polyester, it is difficult to achieve both low-temperature fixability and hot offset resistance, and a wide fixing temperature range cannot be set.

  In addition, a technique of a polyester resin that improves elasticity at a high temperature by using a polyester resin having a crosslinked structure in order to improve hot offset resistance of a polyester having a low melt viscosity is disclosed (for example, Patent Document 1). reference). However, when such a crosslinked structure is introduced, a crosslinked portion having a high melting temperature inhibits low-temperature fixability and improves hot offset resistance, but there is a problem that low-temperature fixability is easily impaired. In addition, the use of polyester having a crosslinked structure has a drawback in that the method for producing the toner is restricted.

On the other hand, it is already known that a block copolymer is introduced into a toner in order to improve fixability, hot offset resistance and the like. For example, in Patent Document 2, a toner in which a thermoplastic elastomer having a block structure is introduced into a core material of a capsule toner, Patent Document 3 contains a thermoplastic elastomer having a block structure and has a storage elastic modulus at 200 ° C. A toner for developing an electrostatic charge image of 8.0 × 10 ^{5 to} 1.0 × 10 ⁴ (dyn / cm ² ) is disclosed. Patent Document 4 proposes a toner containing a polar group-containing block copolymer. However, these toners cannot ensure a sufficient fixing temperature range. Further, depending on the relationship between the binder resin and the block copolymer, the block copolymer may not be uniformly dispersed inside the toner, and the block copolymer is localized on the toner surface, resulting in poor toner fluidity. There may be image quality problems such as fogging.

  Patent Document 5 proposes a toner containing a polyester resin as a binder resin and a block copolymer having a polyolefin skeleton. Although the wax dispersibility was improved by using an ester-olefin block copolymer, this was insufficient in improving the offset resistance.

  As described above, many studies have been made on the toner resin configuration and the elastic component applying method that expand the fixable temperature range without impairing the fixability, but the total performance including developability and the like has not been sufficient. . Moreover, the fact that an elastic component can be imparted without impairing the fixability suggests that the gloss can be controlled from a low gloss to a high gloss without impairing the fixability, which is also considered an important technique in that respect.

JP 2009-223281 A JP-A-6-175389 Japanese Patent Laid-Open No. 7-271096 JP 2004-258429 A JP 2010-102117 A

  The present invention has been made in view of the above circumstances, and its purpose is to maintain excellent low-temperature fixability and hot offset resistance, and to provide excellent static durability with high image quality over a long period of time. An object is to provide a toner for developing a charge image.

  The above object of the present invention is achieved by the following means.

  1. An electrostatic charge image developing toner containing a binder resin, a release agent, and a colorant, wherein the binder resin contains a polyester resin and a block copolymer K, and the block copolymer K includes: A toner for developing an electrostatic charge image, comprising a polymer block A composed of a styrene monomer and a polymer block B composed of a conjugated diene monomer.

  2. 2. The toner for developing an electrostatic charge image according to 1 above, wherein the block copolymer K has a carboxy group.

  By the above means of the present invention, it is possible to provide a toner for developing an electrostatic charge image that retains excellent low-temperature fixability and hot offset resistance, obtains high image quality over a long period of time, and is excellent in durability.

  The present invention relates to a toner for developing an electrostatic charge image (hereinafter, also simply referred to as toner) containing a binder resin, a release agent and a colorant, and a polyester resin and a block copolymer K are used as the binder resin. The block copolymer K is characterized by containing a polymer block A composed of a styrene monomer and a polymer block B composed of a conjugated diene monomer.

  In the present invention, particularly as a binder used for a toner, a block copolymer having a polyester resin and a polymer block A composed of a styrene monomer and a polymer block B composed of a conjugated diene monomer is used. An electrostatic charge image developing toner that retains hot offset resistance, has high image quality over a long period of time, and is excellent in durability can be obtained.

(Binder resin)
The toner of the present invention contains a polyester resin and a block copolymer K as a binder resin.

[Polyester resin]
The polyester resin constituting the binder resin is a resin produced from a known divalent or higher alcohol component and a known divalent or higher carboxylic acid component.

  The polyvalent carboxylic acid to form the polyester resin is a divalent or higher carboxylic acid such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid. Dicarboxylic acids such as fumaric acid, citraconic acid, itaconic acid, glutaconic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid ; Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid and naphthalenedicarboxylic acid; trivalent or higher carboxylic acids such as trimellitic acid, pyromellitic acid, acid anhydrides or acid chlorides thereof, etc. Can do. These can be used alone or in combination of two or more.

  Moreover, as polyhydric alcohol which should form a polyester resin, more than bivalent alcohol, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol 1,4-butylene diol, neopentyl glycol, 1,5-pentane glycol, 1,6-hexane glycol, 1,7-heptane glycol, 1,8-octanediol, 1,9-nonanediol, 1,10 -Decanediol, pinacol, cyclopentane-1,2-diol, cyclohexane-1,4-diol, cyclohexane-1,2-diol, cyclohexane-1,4-dimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol Diols such as diol, polytetramethylene glycol, bisphenol A, bisphenol Z, hydrogenated bisphenol A; 3 such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, trisphenol PA, phenol novolak, cresol novolak Examples thereof include polyhydric aliphatic alcohols having a valence of at least; alkylene oxide adducts of the above-mentioned trihydric or higher polyhydric aliphatic alcohols. These can be used alone or in combination of two or more.

  As the polyester resin, a linear polyester resin among the above-described resins is particularly preferably used from the viewpoint of low-temperature fixability and body offset property.

  Here, the linear polyester resin is a polyester having an insoluble content in tetrahydrofuran (THF) at 25 ° C. of 1% or less.

  Although a plurality of polyester resins may be used, it is a preferred embodiment that all the polyester resins used are linear polyester resins.

  Moreover, it is preferable that the mass average molecular weight (Mw) of a polyester resin is 1,000-100,000, More preferably, it is 1,500-50,000. Moreover, it is preferable that ratio Mw / Mn of a mass average molecular weight (Mw) and a number average molecular weight (Mn) is 1.2-6, More preferably, it is 1.5-5.0.

  The average molecular weight of the polyester resin is measured by a GPC-8220 GPC (manufactured by Tosoh Corp.) measuring device by GPC (gel permeation chromatography).

  The average molecular weight is a value measured by a GPC-8220 GPC (manufactured by Tosoh Corporation) measuring device by GPC (gel permeation chromatography).

  As measurement conditions, a column (TSK-gel SuperHZM-H 15 cm column manufactured by Tosoh Corporation was used in triplicate) in a 40 ° C. heat chamber, and tetrahydrofuran at 1 ml / ml as a solvent was added to the column at this temperature. The measurement may be performed by injecting 50 to 200 μl of a tetrahydrofuran sample solution of a resin prepared at a flow rate of minutes and a sample concentration of 0.05 to 0.6% by mass.

  Using a standard polystyrene sample, the number average molecular weight (Mn) and the mass average molecular weight (Mw) of the toner are calculated using a molecular weight calibration curve prepared from at least about 10 standard polystyrene samples. A refractive index detector is used as the detector.

  Moreover, it is preferable that the glass transition point of a polyester resin is 20-70 degreeC, More preferably, it is 35-60 degreeC.

  Furthermore, the softening point temperature is preferably 80 to 110 ° C, more preferably 90 to 105 ° C.

[Block copolymer K]
The block copolymer K contains a polymerization block A composed of a styrene monomer and a polymerization block B composed of a conjugated diene monomer.

  The arrangement of the blocks of the block copolymer K is preferably an AB type or ABA type in which the blocks are alternately connected in series.

  In the toner for developing an electrostatic charge image of the present invention, the content ratio of the polymer block A and the polymer block B in the block copolymer K is 4/6 to 1 in terms of (content of block A / content of block B). / 9, preferably 3/7 to 2/8.

  The length of the polymer block A in the block copolymer K is 9000 to 120,000 in terms of standard polystyrene equivalent mass average molecular weight (hereinafter also simply referred to as “mass average molecular weight”) (Mw). The length of the polymer block B is preferably 21,000 to 280,000 in terms of mass average molecular weight (Mw).

  The mass average molecular weight (Mw) of the block copolymer K is 20,000 to 1,500,000, preferably 40,000 to 800,000, from the viewpoints of low-temperature fixability and fixing offset resistance.

[Polymerization block A, polymerization block B]
The polymerization block A is composed of a (co) polymer block (hereinafter also referred to as “styrene (co) polymer block”) using a styrene monomer.

  Examples of the styrene monomer for obtaining the styrene (co) polymer block include styrene and styrene having a substituent.

  The polymer block B of the block copolymer K constituting the binder resin of the toner of the present invention is a (co) polymer block (hereinafter also referred to as “diene (co) polymer block”) using a diene monomer. It will be. This polymerization block B may be hydrogenated, and from the viewpoint of durability, it is preferable to be hydrogenated.

  Examples of the diene monomer for obtaining the diene (co) polymer block include butadiene, isoprene, 2-chloro 1,3-butadiene, 2-methyl 1,3-butadiene and the like.

[Carboxyl group-containing block copolymer K]
In the present invention, the block copolymer K preferably has a carboxyl group.

  In the electrostatic image developing toner of the present invention, it is preferable that at least one of the polymer blocks A and B of the block copolymer K contains a carboxyl group. From the viewpoint of production stability, the diene (co) polymer block, that is, the polymer block B preferably contains a carboxyl group.

  The method for introducing a carboxyl group into the diene (co) polymer block, that is, the method for acid modification is not particularly limited. For example, an unmodified block copolymer by the polymer block A and the polymer block B is obtained. A method of reacting an unsaturated carboxylic acid monomer is preferable because the acid value can be easily controlled.

  The unsaturated carboxylic acid monomers for this purpose include maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, aconitic acid, maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, anhydrous Examples include aconitic acid, norbornene dicarboxylic acid anhydride, and tetrahydrophthalic acid anhydride.

  As the addition amount of the unsaturated carboxylic acid monomer, when reacting with an unmodified block copolymer as described later, 0.1 to 10 parts by mass with respect to 100 parts by mass of the unmodified block copolymer. It is preferable that

  Specific methods for reacting the unsaturated carboxylic acid monomer include, for example, (1) a method of melt-kneading in the presence of an organic peroxide, or (2) a reaction in a solvent in the presence of an organic peroxide. The method of letting it be mentioned.

  Specifically, the above method (1) is a known mixing method, for example, using a mixer such as a Banbury mixer or a kneader, or an extruder, and using an organic peroxide, an unsaturated carboxylic acid monomer, and an unmodified monomer. In this method, the block copolymer is mixed at the melting temperature of the unmodified block copolymer.

  In the method (2), specifically, an unmodified block copolymer not containing a carboxyl group is dissolved in a solvent such as toluene, and an unsaturated carboxylic acid monomer and an organic peroxide are added thereto. This is a method in which a product is added, reacted under heating and stirring, then cooled, a poor solvent such as acetone is added to precipitate a product, and washed and dried as necessary.

  The organic peroxide used for the acid modification of the block copolymer is not particularly limited, and examples thereof include benzoyl peroxide, dicurmyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy). ) Hexane, α, α'-bis (t-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, t-butylcumyl peroxide , Di-t-butyl peroxide, t-butyl peroxyisopropyl carbonate, t-butyl peroxybenzoate and the like. These can be used individually by 1 type or in mixture of 2 or more types.

  The amount of the organic peroxide added is usually 0.1 to 5 parts by mass with respect to 100 parts by mass of the unmodified block copolymer.

  The acid value of the block copolymer K is 1.0 KOHmg / g or more and 50.0 KOHmg / g or less, preferably 3.0 KOHmg / g or more and 30.0 KOHmg / g or less, from the viewpoint of fixing offset resistance.

  The value of the acid value is a value measured according to the measuring method described in JIS K0070.

(Content of block copolymer K)
In the toner of the present invention, the content of the block copolymer K is 1 to 20 parts by mass, particularly preferably 5 with respect to 100 parts by mass of the polyester resin, from the viewpoints of low-temperature fixing performance and offset resistance in a high-temperature region. -10 parts by mass.

  The reason why the toner of the present invention improves the low-temperature fixability and the high-temperature offset resistance by containing a combination of the polyester resin and the block copolymer K as the binder resin is clearly as follows. Guessed.

  Since the block copolymer K has a difference in SP value from that of the polyester, the block copolymer K is finely dispersed without being incompatible, so that the block copolymer does not hinder the melting characteristics of the polyester. It is presumed that the elasticity imparting ability can be efficiently expressed, so that it can be fixed at low temperature and is excellent in high temperature offset property.

  Further, since the block copolymer K is difficult to localize on the toner surface, it is difficult to adversely affect the powder characteristics, and a stable image quality is easily obtained.

  Further, the block copolymer K preferably has a carboxyl group, but this is because part of the block copolymer has polarity, so that the block copolymer and the polyester are incompatible with each other while interacting with each other. By having a point, it is presumed that elasticity is effectively imparted even when the addition amount of the block copolymer is smaller.

[Colorant]
As the colorant contained in the toner of the present invention, generally known dyes and pigments can be used.

  As a colorant for obtaining a black toner, various known ones such as carbon black, a magnetic material, a dye, and a pigment can be arbitrarily used.

  The colorant for obtaining the toner of each color can be used alone or in combination of two or more for each color.

  The content of the colorant is preferably 1 to 10% by mass, more preferably 2 to 8% by mass in the toner from the viewpoint of coloring power and chargeability.

〔Release agent〕
In addition to the binder resin and the colorant, the toner particles constituting the toner of the present invention contain a release agent that contributes to the suppression of the offset phenomenon.

  The release agent is not particularly limited, and examples thereof include polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, carnauba wax, sazol wax, rice wax, and candelilla wax. Can do.

  The content ratio of the release agent in the toner particles is usually 0.5 to 5 parts by mass, preferably 1 to 3 parts with respect to 100 parts by mass of the binder resin in terms of offset property, translucency, and color reproducibility. Part by mass.

[Charge control agent]
In addition to the binder resin and the colorant, the toner particles constituting the toner of the present invention may contain a charge control agent as necessary. Various known compounds can be used as the charge control agent.

[Toner Production Method]
The method for producing the toner of the present invention is not particularly limited, and examples thereof include a pulverization method, a suspension polymerization method, an emulsion polymerization association method, a dissolution suspension method, and other known methods. In order to achieve high image quality, it is necessary to obtain a toner having a reduced particle size, and from the viewpoint of uniformly incorporating the block copolymer K into the polyester resin, the following aggregation method is included. The method is preferred.

  That is, (1) Polyester resin and block copolymer K are dissolved in an organic solvent to form a “composite resin dispersion” in which “droplets of a polyester resin solution containing a block copolymer” are dispersed in an aqueous medium. (2) Step of removing solvent after at least the step of (1) and forming a “composite resin particle” dispersion, and (3) agglomerating the “composite resin particle” and colorant particles. A toner production method comprising:

  In the step of aggregating the “composite resin particles” and the colorant particles, a dispersion of fine particles made of a binder resin is mixed with a dispersion of toner particle components such as other colorant fine particles, and the surface of the fine particles is adjusted by adjusting pH. Aggregating slowly while balancing the repulsive force and the agglomeration force due to the addition of an aggregating agent composed of an electrolyte, and performing association while controlling the average particle size and particle size distribution. In this method, toner particles are manufactured by controlling the shape of the toner particles.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

[Preparation of Block Copolymer K-1]
An autoclave having an internal volume of 5 liters was charged with 2500 g of degassed cyclohexane and 75 g of styrene, 75 g of tetrahydrofuran and 0.4 g of n-butyllithium were added, and adiabatic polymerization was performed from 50 ° C. After completion of the reaction, the reaction solution was brought to 30 ° C., and 350 g of 1,3-butadiene was added to conduct adiabatic polymerization. After completion of the reaction, 75 g of styrene was further added to conduct adiabatic polymerization. After the polymerization was completed, the resulting polymerization reaction solution was poured into methanol, and the precipitated solid was filtered off and dried at 50 ° C. for 20 hours to obtain a block copolymer [K-0].

  100 g of block copolymer [K-0] is dissolved in 700 g of toluene and heated to 140 ° C., then 1.0 g of maleic anhydride and 1.0 g of dicurmyl peroxide are added and reacted for 4 hours with stirring. It was. Thereafter, the mixture was cooled, acetone was added to precipitate the product, washed and dried to obtain a block copolymer [K-1] having a carboxyl group introduced.

  The acid value of the obtained block copolymer [K-1] was 3.4 mgKOH / g.

  The obtained block copolymer [K-1] has a mass average molecular weight (Mw) of 130,000, the content of the structural unit derived from styrene in the block copolymer [K-1] is 30% by mass, and the vinyl bond. The content was 70%.

[Preparation of block copolymer K-2]
An autoclave having an internal volume of 5 liters was charged with 2500 g of degassed cyclohexane and 50 g of styrene, 75 g of tetrahydrofuran and 0.4 g of n-butyllithium were added, and adiabatic polymerization was performed from 50 ° C. After completion of the reaction, the reaction solution was brought to 30 ° C., and 400 g of isoprene was added to conduct adiabatic polymerization. After completion of the reaction, 50 g of styrene was further added to conduct adiabatic polymerization. After the polymerization was completed, the resulting polymerization reaction solution was poured into methanol, and the precipitated solid was filtered off and dried at 50 ° C. for 20 hours to obtain a block copolymer [K-2].

  The obtained block copolymer [K-2] has a mass average molecular weight (Mw) of 150,000, the content of structural units derived from styrene in the block copolymer [K-2] is 20% by mass, The content was 80%.

[Preparation of block copolymer K-3]
After 180 g of the block copolymer [K-0] was dissolved in 2500 g of cyclohexane, 10 g of palladium carbon was added as a hydrogenation catalyst, and the reaction was carried out for 8 hours under conditions of a hydrogen pressure of 2 MPa and 150 ° C. After allowing to cool and release, palladium carbon was removed by filtration, and then the filtrate was concentrated and further vacuum dried to obtain a hydrogenated block copolymer [K-3].

  The obtained block copolymer [K-3] has a mass average molecular weight (Mw) of 130,000, the content of structural units derived from styrene in the block copolymer [K-3] is 30% by mass, The hydrogenation rate was 90%.

[Preparation of block copolymer K-4]
100 g of block copolymer [K-3] is dissolved in 700 g of toluene and heated to 140 ° C., then 9.0 g of maleic anhydride and 3.0 g of dicurmyl peroxide are added and reacted for 4 hours with stirring. It was. Thereafter, the mixture was cooled, acetone was added to precipitate the product, and washing and drying were performed to obtain a block copolymer [K-4] into which a carboxyl group was introduced.

  The acid value of the obtained block copolymer [K-4] was 30.0 mgKOH / g.

  Table 1 shows the composition and physical properties of the block copolymer obtained by the above operation.

[Preparation of Block Copolymer K-5 (Comparative Example)]
In accordance with the description in Example 1 of JP 2010-102117 A, a polyolefin / polyester copolymer (1) was prepared and designated as block copolymer K-5.

[Preparation of Polyester Resin PE-1 (Linear Polyester)]
The following polyhydric carboxylic acid monomer and polyhydric alcohol monomer were charged into a 5 liter flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectifying column.

Terephthalic acid: 37 parts Bisphenol A / PO2 molar adduct: 52 parts Bisphenol A / EO2 molar adduct: 11 parts The charged monomer was raised to 190 ° C. over 1 hour, and the reaction system was uniformly stirred. After confirmation, catalyst Ti (OBu) ₄ (0.003% by mass with respect to the total amount of the polyvalent carboxylic acid monomer) was added. Furthermore, the temperature was raised to 240 ° C. over 6 hours from the same temperature while distilling off generated water. The dehydration condensation reaction was continued at 240 ° C. for an additional 6 hours, and polymerization was performed to obtain a polyester resin PE-1.

  Polyester resin PE-1 obtained had an Mw of 6,500, a glass transition temperature of 55 ° C., and a tetrahydrofuran insoluble content of 0%.

[Production of Polyester Resin PE-2 (Linear Polyester)]
It produced by the method similar to polyester PE-1 except having used the following polycarboxylic acid monomer and polyhydric alcohol monomer.

Terephthalic acid: 35 parts Fumaric acid: 10 parts Bisphenol A · PO2 molar adduct: 28 parts 1,6-hexanediol: 27 parts The obtained polyester PE-2 has an Mw of 11,000, a glass transition temperature of 52 ° C, Tetrahydrofuran insoluble content was 0%.

[Preparation of polyester resin PE-3 (non-linear polyester)]
It produced by the method similar to polyester PE-2 except having used the following polycarboxylic acid monomer and polyhydric alcohol monomer.

Terephthalic acid: 37 parts Trimellitic anhydride: 11 parts Bisphenol A / PO2 molar adduct: 42 parts Bisphenol A / EO2 molar adduct: 10 parts Mw of the obtained polyester resin PE-3 is 14,000, glass transition temperature Was 58 ° C. and the tetrahydrofuran insoluble content was 5%.

[Production of Composite Polyester Resin Particle Dispersion D-1 Containing Block Copolymer]
10 parts of block copolymer K-1, 82 parts by weight of polyester resin PE-2, 8 parts of carnauba wax, 50 parts of ethyl acetate, 25 parts by weight of isopropyl alcohol, and 5 parts by weight of 10% aqueous ammonia solution After putting into a separable flask, mixing and dissolving, ion-exchanged water was added dropwise at a liquid feed rate of 8 g / min with a liquid feed pump while stirring at 40 ° C. After the liquid became cloudy, the liquid feeding speed was increased to 25 g / min to cause phase inversion, and dropping was stopped when the liquid feeding amount reached 135 parts by mass. Thereafter, the solvent was removed under reduced pressure to obtain a composite polyester resin particle dispersion D-1.

[Preparation of Composite Polyester Resin Particle Dispersion D-2 Containing Block Copolymer]
A composite polyester resin particle dispersion D-2 was prepared in the same manner as the composite polyester resin particle dispersion D-1, except that the block copolymer K-1 used was changed to K-2.

[Production of Composite Polyester Resin Particle Dispersion D-3 Containing Block Copolymer]
A composite polyester resin particle dispersion D-3 was produced in the same manner as the composite polyester resin particle dispersion D-1, except that the block copolymer K-1 used was changed to K-3.

[Preparation of Composite Polyester Resin Fine Particle Dispersion D-4 Containing Block Copolymer]
A composite polyester resin particle dispersion D-4 was produced in the same manner as the composite polyester resin particle dispersion D-1, except that the block copolymer K-1 used was changed to K-4.

[Production of Composite Polyester Resin Fine Particle Dispersion D-5 Containing Block Copolymer]
The composite polyester resin particle dispersion is the same as the composite polyester resin particle dispersion D-1, except that the block copolymer K-1 used is changed to K-4 and the polyester resin PE-1 is changed to PE-2. Liquid D-5 was produced.

[Production of Composite Polyester Resin Fine Particle Dispersion D-6 Containing Block Copolymer]
A composite polyester resin particle dispersion liquid was prepared in the same manner as the composite polyester resin particle dispersion liquid D-1, except that the addition amount of the polyester resin PE-1 was changed from 90 parts to 100 parts without using a block copolymer. D-6 was produced.

[Production of Composite Polyester Resin Fine Particle Dispersion D-7 Containing Block Copolymer]
Except for using K-4 instead of the block copolymer K-1 and using polyester PE-3 instead of polyester PE-1, in the same manner as the composite polyester resin particle dispersion D-1, A composite polyester resin fine particle dispersion D-7 was prepared.

[Production of Composite Polyester Resin Fine Particle Dispersion D-8 Containing Block Copolymer]
A composite polyester resin fine particle dispersion D-8 was prepared in the same manner as the composite polyester resin particle dispersion D-1, except that K-5 was used instead of the block copolymer K-4 used.

  Table 2 shows the block copolymer K and the polyester resin used in the above composite polyester resin particle dispersion.

[Preparation Example of Colorant Particle Dispersion]
While stirring a solution obtained by adding 90 parts by mass of sodium dodecyl sulfate to 1600 parts by mass of ion-exchanged water, 420 parts by mass of carbon black “Regal 330R” (manufactured by Cabot Corp.) is gradually added, and then a stirrer “Clearmix” A colorant particle dispersion was prepared by performing dispersion treatment using (M Technique Co., Ltd.).

  It was 110 nm when the particle diameter of the colorant particle in this colorant particle dispersion was measured using an electrophoretic light scattering photometer “ELS-800 (manufactured by Otsuka Electronics Co., Ltd.)”.

[Production of Toner 1]
An aqueous solution in which 1400 parts by mass of ion-exchanged water and 3 parts by mass of sodium polyoxyethylene (2) dodecyl ether sulfate are added to 120 parts by mass of ion-exchanged water in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device. Add 123 parts by weight,
Composite polyester resin particle dispersion D-1 290 parts by mass (solid content conversion)
120 parts by mass of the colorant fine particle dispersion was added, and the liquid temperature was adjusted to 30 ° C.

Next, a 5 mol / liter aqueous sodium hydroxide solution was added to adjust the pH to 10, and a 30 ° C. aqueous solution in which 35 parts by mass of magnesium chloride was dissolved in 35 parts by mass of ion-exchanged water was stirred. Added to the system over 10 minutes. Then, after 3 minutes had elapsed after the addition, the temperature was started to rise, and the temperature of the reaction system was raised to 90 ° C. over 60 minutes to advance the aggregation. While measuring the size of the aggregated particles formed by aggregation with “Multisizer 3” (manufactured by Beckman Coulter), when the volume-based median diameter (D ₅₀ ) becomes 6.5 μm, 20% chloride 750 parts by mass of an aqueous sodium solution was added to stop particle growth.

  After the addition of the aggregation terminator, stirring was continued at a liquid temperature of 98 ° C., and the aggregated particles were observed while observing the average circularity of the aggregated particles with a flow type particle image analyzer “FPIA-2100” (manufactured by Sysmex Corporation). After the adhesion of the fine resin particles was progressed and the average circularity reached 0.965, the liquid temperature was cooled to 30 ° C., hydrochloric acid was added to adjust the pH to 4.0, and the stirring was stopped.

  The agglomerated particles are solid-liquid separated by a basket-type centrifuge “MARKIII model number 60 × 40” (Matsumoto Machine Co., Ltd.) to form a wet cake of the agglomerated particles, which is separated by the basket-type centrifuge. The filtrate is washed with ion-exchanged water at 45 ° C. until the electrical conductivity reaches 5 μS / cm, then transferred to “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.), and dried until the water content becomes 0.5 mass% As a result, toner particles [1] were obtained.

  1% by mass of hydrophobic silica (number average primary particle size = 12 nm) and 0.3% by mass of hydrophobic titania (number average primary particle size = 20 nm, degree of hydrophobicity = 63) are added to the toner particles [1]. Then, they were mixed by “Henschel mixer” (manufactured by Mitsui Miike Chemical Co., Ltd.). Thereafter, toner 1 was produced by removing coarse particles using a sieve having an opening of 45 μm.

  The toner particles did not change in particle diameter and average circularity depending on the addition of hydrophobic silica.

[Production of Toners 2 to 8]
In the production of the toner 1, toners 2 to 8 were obtained in the same manner except that D-2 to D-8 were used instead of the composite polyester resin particle dispersion D-1.

(Development of developer)
To these toners 1 to 8, a ferrite carrier having a volume-based median diameter of 60 μm and coated with a silicone resin was mixed so that the concentration of the developer toner was 6% by mass to prepare developers 1 to 9.

[Evaluation 1: Fixable temperature range]
In a commercially available copy printer “bizhub PRO C500” (manufactured by Konica Minolta Business Technologies, Inc.), the fixing device is modified so that the surface temperature of the heating roller can be changed in the range of 120 to 200 ° C. The fixing temperature (surface temperature of the heating roller) is set to 120 ° C. in a fixing experiment in which a solid band image having a width of 5 mm extending in the axial direction of the heating roller is fixed at normal temperature and humidity (temperature 20 ° C., relative humidity 55%). , 125 ° C., and so on, with repeated changes in increments of 5 ° C.

  In each fixing experiment, the obtained fixed image was rubbed 10 times with an exposed cloth at a pressure of 1 Pa, the reflection density before and after the measurement was measured, and the fixing rate was measured from the difference according to the following formula (2). Among the fixing experiments that reached% or more, the fixing temperature of the fixing experiment relating to the lowest fixing temperature was measured as the minimum fixing temperature, and used as an index of low-temperature fixing property.

Formula (2): Fixing rate (%) = {(reflection density after rubbing) / (reflection density before rubbing)} × 100
Further, among fixing experiments in which image staining due to high temperature offset was visually observed, the fixing temperature of the fixing experiment relating to the lowest fixing temperature was measured as a high temperature offset temperature, and used as an index of high temperature offset resistance. The results are shown in Table 2. In Table 2, “not generated” means that no high temperature offset occurred up to 200 ° C.

[Evaluation 2: Image stability against environmental changes]
After continuously running 100,000 character images with a printing rate of 10% in an L / L environment (10 ° C., 15% RH) and an H / H environment (30 ° C., 85% RH), The roughness of the halftone image was visually observed to evaluate the image stability and used as an index of durability.

(Image stability)
A: No decrease in image density and no fogging occurred. O: A decrease in image density and / or fogging was slightly confirmed with a 20-fold magnifier, but at a level causing no practical problems.
X: Image density decreased and fogging occurred, and there were practical problems.

  The evaluation results are shown in Table 3.

  From the table, it can be seen that by using the toner of the present invention, excellent low-temperature fixability and hot offset resistance can be obtained, and high image quality can be obtained over a long period of time.

Claims (2)

  An electrostatic charge image developing toner containing a binder resin, a release agent, and a colorant, wherein the binder resin contains a polyester resin and a block copolymer K, and the block copolymer K includes: A toner for developing an electrostatic charge image, comprising a polymer block A composed of a styrene monomer and a polymer block B composed of a conjugated diene monomer.   The electrostatic charge image developing toner according to claim 1, wherein the block copolymer K has a carboxy group.