JP2013160807A - Toner for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner having excellent fixation separability.SOLUTION: A toner for electrostatic charge image development contains a polyester resin and a styrene-acrylic modified polyester resin. A carboxyl group present in the styrene-acrylic modified polyester resin is modified with a compound having at least one substituent group selected from the group consisting of an oxazoline group, a glycidyl group, an aziridine group, and a carbodiimide group.

Description

  The present invention relates to a toner for developing an electrostatic image. More specifically, the present invention relates to an electrostatic charge image developing toner used in an electrophotographic image forming apparatus.

  In recent years, in the field of electrostatic image developing toner, development of an electrophotographic apparatus suitable for the demand from the market and a toner usable for the electrophotographic apparatus are proceeding at a rapid pace. For example, a toner compatible with high image quality is required to have a sharp particle size distribution. When the toner particle size is uniform and the particle size distribution is sharpened, the development behavior of each individual toner particle is uniformed, so that the reproducibility of minute dots is remarkably improved. However, it is not easy to sharpen the particle size distribution of the toner by a conventional toner manufacturing method using a pulverization method.

  On the other hand, an emulsion aggregation method has been proposed as a production method capable of arbitrarily controlling the shape and particle size distribution of toner particles. In this method, a colorant particle dispersion and, if necessary, a wax dispersion are mixed with an emulsion dispersion of resin particles, and while stirring, each particle is aggregated by addition of a flocculant, pH control, and the like. The toner particles are obtained by fusing the particles.

  Further, from the viewpoint of energy saving, development of a low-temperature fixing toner that can be fixed with less energy is in progress. In order to lower the fixing temperature of the toner, it is necessary to lower the melting temperature and melt viscosity of the binder resin. However, if the glass transition point or molecular weight of the binder resin is lowered in order to lower the melting temperature or melt viscosity of the binder resin, new problems such as a decrease in heat resistant storage stability and fixing separation performance of the toner arise.

  In view of the above problems, for the purpose of developing a toner having excellent storage stability and a wide fixing temperature range, a carboxyl group of a polyester (binder resin) containing a structural unit derived from a trivalent or higher carboxylic acid; An electrophotographic toner obtained by chemically bonding a compound having a functional group capable of reacting with the carboxyl group has been reported (see Patent Document 1).

JP 2009-58927 A

  Generally, a toner contains a release agent (wax) in addition to a binder resin and a colorant. However, when the toner described in Patent Document 1 is used, the affinity between the polyester used as the binder resin and the release agent is low. For this reason, even if an attempt is made to prepare a toner by mixing a binder resin, a colorant, and a release agent, a necessary amount of the release agent cannot be dispersed in the toner, and there is a problem that the fixing separation property of the toner is not sufficient. . Patent Document 1 describes that a styrene-acrylic copolymer may be used in addition to polyester (paragraph “0008”). However, although the styrene-acrylic copolymer has a higher affinity with the release agent than the polyester, the affinity with the polyester is low. For this reason, when a styrene-acrylic copolymer is used in addition to polyester, there is a problem that sufficient integrity (cohesiveness) cannot be ensured at the time of toner formation.

  Accordingly, the present invention has been made in view of the above circumstances, and an object thereof is to provide a toner having excellent fixing and separating properties.

  Another object of the present invention is to provide a toner having excellent low-temperature fixability.

  As a result of intensive studies to solve the above problems, the inventors of the present application have found that a resin obtained by modifying a styrene-acryl-modified polyester resin with a compound having a specific substituent is a binder at the time of toner preparation. The inventors have found that the object can be achieved by using the resin, and have completed the present invention.

  That is, the above-mentioned problem is a toner for developing an electrostatic charge image containing a polyester resin and a styrene-acryl-modified polyester resin, wherein the carboxyl group present in the styrene-acryl-modified polyester resin is an oxazoline group, a glycidyl group, an aziridine group. And an electrostatic image developing toner characterized by being modified with a compound having at least one substituent selected from the group consisting of carbodiimide groups.

  According to the present invention, a toner having excellent fixing and separating properties can be obtained.

  The present invention is an electrostatic charge image developing toner comprising a polyester resin and a styrene-acryl-modified polyester resin, wherein the carboxyl group present in the styrene-acryl-modified polyester resin is an oxazoline group, a glycidyl group, an aziridine group, and A toner for developing an electrostatic image, characterized by being modified with a compound having at least one substituent selected from the group consisting of carbodiimide groups (hereinafter, also simply referred to as “substituent-containing compound”) Simply referred to as “toner”). The reason why the toner according to the present invention is excellent in low-temperature fixing property and fixing separation property is not clear, but is presumed as follows. In addition, this invention is not limited by the following guess. That is, a styrene-acryl-modified polyester resin in which a carboxyl group of a styrene-acryl-modified polyester resin is modified with a substituent-containing compound (hereinafter, also simply referred to as “modified styrene-acryl-modified polyester resin”) is hydrophobic. Since the unit can improve the affinity with the release agent, a necessary amount of the release agent can be finely dispersed in the toner (the dispersion state in the toner can be improved). Moreover, the modified styrene-acrylic modified polyester resin according to the present invention has an appropriate affinity with the polyester resin. For this reason, the toner of the present invention has a good balance of affinity for both the release agent and the polyester resin. Further, by using a modified styrene-acryl modified polyester resin, the softening point of the toner can be set high. Therefore, the toner of the present invention can exhibit good fixing separation and heat-resistant storage properties.

  In addition to the above, the carboxyl group in the styrene-acryl-modified polyester resin is modified with a substituent-containing compound to form a crosslinked structure of polyester molecular chains. Therefore, the toner of the present invention is given elasticity at high temperature, and the hot offset resistance and the fixing separation property can be improved.

  The toner of the present invention contains a polyester resin. Here, while the polyester resin has a high glass transition point, it has a high sharp melt property. For this reason, it is possible to melt instantaneously at the time of fixing and penetrate into a recording medium such as paper and give a strong fixing property. Therefore, the toner of the present invention can exhibit good low-temperature fixability.

  Therefore, the toner of the present invention can achieve both the contradictory performances of low-temperature fixability and fixability. In particular, when the carboxyl group present in the polyester resin is modified with a substituent-containing compound, the above effect can be exhibited more remarkably.

  Embodiments of the present invention will be described below.

≪Modification of polyester binder resin with substituent-containing compound≫
As one of the features of the present invention, the carboxyl group present in the styrene-acryl-modified polyester resin contained in the toner as a binder resin is at least selected from the group consisting of an oxazoline group, a glycidyl group, an aziridine group, and a carbodiimide group. It may be modified with a substituent-containing compound having a kind of substituent. Preferably, the carboxyl group present in both the styrene-acrylic modified polyester resin and the polyester resin contained as a binder resin in the toner is modified with a substituent-containing compound, that is, present in the polyester resin and the styrene-acrylic modified polyester resin. The carboxyl group to be modified is preferably modified with a compound having at least one substituent selected from the group consisting of an oxazoline group, a glycidyl group, an aziridine group and a carbodiimide group. Thus, by modifying the carboxyl groups of both the styrene-acryl-modified polyester resin and the polyester resin with a substituent-containing compound, the elasticity at high temperature, the low-temperature fixability, and the fixing separation property are further improved. In addition, modification | denaturation by a substituent containing compound is performed with respect to the carboxyl group which exists in both styrene-acryl modified polyester resin and polyester resin, and the reaction mechanism is the same. For this reason, unless otherwise specified, in this specification, “styrene-acryl-modified polyester resin and / or polyester resin” is also collectively referred to as “polyester binder resin”. In the present invention, it is not necessary for all carboxyl groups present in the styrene-acryl-modified polyester resin or polyester resin to be modified with the substitution-containing compound, and some of the carboxyl groups present in the polyester binder resin are substituted. It may be modified with a group-containing compound.

  Here, the reaction (modification) between the carboxyl group of the polyester binder resin and the substituent-containing compound is performed as follows. In the following reaction, the styrene-acryl-modified polyester resin or polyester resin is simply referred to as “resin”.

  In the above reaction, the polyester binder resin having only one carboxyl group and the substituent-containing compound having only one substituent have been described as examples. Generally, the polyester binder resin has a carboxyl group at both ends. That is, the polyester binder resin has at least two carboxyl groups. Therefore, the substituent-containing compound is preferably a compound having two or more substituents. As a result, the polyester binder resins form a cross-linked structure via the substituent-containing compound, so that the toner of the present invention has an affinity with a release agent, elasticity at high temperatures, hot offset resistance and fixing. Separability can be further improved.

  Here, the compound having an oxazoline group is not particularly limited as long as it has an oxazoline group. For example, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl- 5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2-isopropenyl-5 And ethyl-2-oxazoline. Of these, 2-isopropenyl-2-oxazoline is preferred in consideration of availability and reactivity.

  The compound having a glycidyl group is not particularly limited as long as it has a glycidyl group. For example, glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, glycidyl allyl sulfonate, glycidyl vinyl sulfonate, glycidyl paravinyl benzoate, etc. Is mentioned. Among these, glycidyl methacrylate is preferable in consideration of availability and reactivity.

  The compound having an aziridine group is not particularly limited as long as it has an aziridine group, and examples thereof include 2- (1-aziridinyl) ethyl methacrylate, 2- (1-aziridinyl) ethyl acrylate, methacryloylaziridine, acryloylaziridine and the like. Can be mentioned. Of these, methacryloylaziridine is preferred in consideration of availability and reactivity.

  The compound having a carbodiimide group is not particularly limited as long as it has a carbodiimide group. -Butylcarbodiimide, di-β-naphthylcarbodiimide, N-isopropyl-N ′-[2- (methacryloyloxy) ethyl] carbodiimide and the like. Among these, N-isopropyl-N ′-[2- (methacryloyloxy) ethyl] carbodiimide is preferable in consideration of availability and reactivity.

The above substitution-containing compounds may be used alone or in combination of two or more. In the latter case, two or more compounds having the same substituent may be used in combination or different. You may use the compound which has a substituent 1 type or in combination of 2 or more types.
The substituent-containing compound may be obtained by synthesis or may be a commercially available product.

  The above-mentioned substituent-containing compound may be used as it is, or may be used in the form of a (co) polymer by polymerizing or copolymerizing the compound as a polymerizable monomer. The substituent-containing compound is preferably a (co) polymer from the viewpoint of fixing characteristics of the obtained toner and from the viewpoint of improving the reactivity with the carboxyl group of the binder resin. When the substituent-containing compound is a (co) polymer as described above, the substituent-containing compound becomes a compound having two or more substituents, and thus the polyester binder resins are crosslinked via the substituent-containing compound. By forming a structure, it is possible to further improve the affinity of the toner with the release agent, elasticity at high temperature, resistance to hot offset, and fixing separation.

  When the substituent-containing compound is in the form of a (co) polymer, it may be a (co) polymer composed of one or more of the substituent-containing compounds. Or the copolymer of the 1 type (s) or 2 or more types of the said substituent containing compound, and another monomer may be sufficient. Other monomers that can be used in the latter case are not particularly limited. For example, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, (Meth) acrylic acid isobutyl, (meth) acrylic acid t-butyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid-2-ethylhexyl, (meth) acrylic acid methoxypolyethylene glycol, (meth) acrylic acid lauryl, ( Stearyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, monoesterified product of (meth) acrylic acid and polyethylene glycol, (meth) acrylic acid-2- Aminoethyl and its salts, caprolactone modified product of (meth) acrylic acid, (meth) a (Meth) acrylic acid esters such as lauric acid-2,2,6,6-tetramethylpiperidine, (meth) acrylic acid-1,2,2,6,6-pentamethylpiperidine; sodium (meth) acrylate, (Meth) acrylic acid salts such as potassium (meth) acrylate and ammonium (meth) acrylate; unsaturated nitriles such as acrylonitrile and methacrylonitrile; (meth) acrylamide, N-methylol (meth) acrylamide, N- (2 -Unsaturated amides such as hydroxyethyl) (meth) acrylamide; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; vinyl chloride, vinylidene chloride, fluorine Halogen-containing α, β-unsaturated fats such as vinyl fluoride Family hydrocarbons; styrene, divinylbenzene, alpha-methylstyrene, such as sodium styrene sulfonate alpha, beta-unsaturated aromatic hydrocarbons, and the like. At this time, the content of the other monomer is not particularly limited as long as the effect of the reaction between the carboxyl group of the polyester binder resin and the substituent of the substituent-containing compound is not impaired. Preferably, the content of other monomers is 50 mol% or less, more preferably 10 to 40 mol%, based on all monomers.

  The molecular weight of the (co) polymer when the substituent-containing compound is a (co) polymer is not particularly limited, but is preferably 5000 to 20000, and preferably 10,000 to 15000 from the viewpoint of the crosslinking rate and the like. It is more preferable. The weight average molecular weight can be measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

  In the modification by the substituent of the substituent-containing compound of the carboxyl group of the polyester binder resin, the amount of the substituent-containing compound is not particularly limited as long as it is an amount that can sufficiently modify the carboxyl group present in the polyester binder resin, It depends on the number (amount) of carboxyl groups present in the resin. For example, the amount of the substituent-containing compound is preferably 5 to 30% by mass and more preferably 10 to 20% by mass with respect to the total amount of the polyester binder resin. With such an amount, the carboxyl group of the polyester binder resin can be sufficiently modified with the substituent of the substituent-containing compound.

  Further, the modification conditions by the substituent of the carboxyl group-containing compound of the polyester binder resin are not particularly limited as long as the carboxyl group of the polyester binder resin can be sufficiently modified, and the styrene-acryl modified polyester resin, It can select suitably according to the kind of polyester resin and a substituent containing compound. Specifically, the modification reaction temperature is preferably 80 to 250 ° C, and more preferably 150 to 230 ° C. The modification reaction time is preferably 1 to 6 hours, more preferably 2 to 5 hours. Moreover, although the said reaction may be in the stationary state, when reaction efficiency is considered, it is preferable to carry out under stirring.

≪Styrene-acrylic modified polyester resin≫
The toner of the present invention contains a modified styrene-acryl modified polyester resin as a binder resin. Here, the unmodified styrene-acrylic modified polyester resin used in the present invention is not particularly limited, and a styrene-acrylic modified polyester resin generally used as a binder resin for toner can be used in the same manner. For example, the content ratio of the styrene-acrylic polymer segment in the styrene-acrylic modified polyester resin (hereinafter also referred to as “styrene-acrylic modification amount”) is not particularly limited. The content ratio of the styrene-acrylic copolymer in the styrene-acrylic modified polyester resin is preferably 3 to 35% by mass, more preferably 5 to 30% by mass, and particularly preferably 10 to 20% by mass. . A toner containing a styrene-acryl-modified polyester resin having a styrene-acryl modification amount in such a range as a binder resin is excellent in elasticity at low temperatures, low-temperature fixability, and fixing separation. Here, the “styrene-acryl modified amount” specifically refers to the total mass of the resin material used for synthesizing the styrene-acryl modified polyester resin, that is, the unmodified polyester resin that becomes the polyester segment. Aromatic system based on the total mass of the polymerizable monomer, the aromatic vinyl monomer and (meth) acrylic acid ester monomer to be a styrene-acrylic polymer segment, and the total amount of both reactive monomers for bonding them The mass ratio (%) of the vinyl monomer and the (meth) acrylic acid ester monomer.

  In the toner of the present invention, an aliphatic unsaturated dicarboxylic acid is used as a polyvalent carboxylic acid monomer to form a polyester segment of a styrene-acryl-modified polyester resin, and the aliphatic unsaturated dicarboxylic acid is added to the polyester segment. It is preferable that a structural unit derived from an acid is contained. The aliphatic unsaturated dicarboxylic acid refers to a chain dicarboxylic acid having a vinylene group in the molecule.

  The styrene-acryl modified polyester resin having a structural unit derived from an aliphatic unsaturated dicarboxylic acid has a linear structure in the molecule. For this reason, such a styrene-acrylic modified polyester resin has a higher affinity with a release agent (wax) and can take in a necessary amount of wax, so that the surface becomes smooth and fixing separation is achieved. The property can be further improved.

  Content ratio of structural unit derived from aliphatic unsaturated dicarboxylic acid in structural unit derived from polyvalent carboxylic acid monomer constituting polyester segment of styrene-acryl-modified polyester resin (hereinafter referred to as “specific unsaturated dicarboxylic acid content ratio” Is also preferably 25 mol% or more and 75 mol% or less, and more preferably 30 mol% or more and 60 mol% or less. When the specific unsaturated dicarboxylic acid content ratio is in the above range, the affinity of the toner with the wax is increased and the required amount of wax can be taken in, so that the surface becomes smooth and the fixing separation property is improved. Can be improved. In addition, a toner containing such a styrene-acrylic modified polyester resin as a binder resin exhibits excellent heat resistant storage properties and charging properties.

  The structural unit derived from the aliphatic unsaturated dicarboxylic acid is preferably a structural unit derived from one represented by the following general formula (A). In addition, in this invention, when using aliphatic unsaturated dicarboxylic acid represented by general formula (A) for a polymerization reaction, it can also be used with the form of an anhydride.

In the general formula (A), R ₁ and R ₂ are a hydrogen atom, a methyl group, or an ethyl group, and are preferably a hydrogen atom or a methyl group. At this time, R ₁ and R ₂ may be the same or different from each other. N is an integer of 1 or 2.

  The styrene-acrylic modified polyester resin of the present invention has a glass transition point of 40 to 70 ° C. from the viewpoint of fixing properties such as low-temperature fixing properties and fixing separation properties, and heat resistance properties such as heat-resistant storage properties and blocking resistance. Preferably, it is 50-65 degreeC, and it is preferable that a softening point is 80-110 degreeC.

  The glass transition point (° C.) of the styrene-acrylic modified polyester resin is a value measured by a method (DSC method) defined in ASTM (American Society for Testing and Materials) D3418-82. Specifically, 4.5 mg of the sample was precisely weighed to two digits after the decimal point, sealed in an aluminum pan, and set in a sample holder of a differential scanning calorimeter “DSC8500” (Perkin Elmer). The reference uses an empty aluminum pan, and performs heat-cool-heat temperature control at a measurement temperature of −120 ° C. to 100 ° C., a temperature increase rate of 10 ° C./min, and a temperature decrease rate of 10 ° C./min. 2nd. Analysis was performed based on the data in Heat. The value of the intersection of the base line extension before the rise of the first endothermic peak and the tangent indicating the maximum slope between the rise of the first endothermic peak and the peak apex is the glass transition temperature (glass transition point; ° C).

Moreover, the softening point (° C.) of the styrene-acrylic modified polyester resin is a value measured as follows. First, in an environment of 20 ° C. ± 1 ° C. and 50% ± 5% RH, 1.1 g of resin is placed in a petri dish, flattened, and left for 12 hours or more. Then, a molding machine “SSP-10A” (manufactured by Shimadzu Corporation) ) For 30 seconds with a force of 3820 kg / cm ² to produce a cylindrical molded sample having a diameter of 1 cm, and this molded sample is then subjected to an environment of 24 ° C. ± 5 ° C. and 50% ± 20% RH. With a flow tester “CFT-500D” (manufactured by Shimadzu Corporation), a cylindrical die hole (1 mm diameter ×× 1 kg), with a load of 196 N (20 kgf), a starting temperature of 60 ° C., a preheating time of 300 seconds, and a heating rate of 6 ° C./min. than 1 mm), extruded from the time of preheating ends with piston diameter 1 cm, offset method temperature _{T offset} measured by setting the offset value 5mm at a melt temperature measurement method of temperature ramps are resin It is the softening point (° C.).

(Method for producing styrene-acrylic modified polyester resin)
As a method for producing the styrene-acrylic modified polyester resin, an existing general scheme can be used. Typical methods include the following four methods (A) to (D).
(A) A polyester segment is polymerized in advance, and an aromatic vinyl monomer and a (meth) acrylic acid ester monomer for forming a styrene-acrylic polymer segment are reacted with the polyester segment via both reactive monomers. A method of forming a styrene-acrylic polymer segment by
(B) A styrene-acrylic polymer segment is preliminarily polymerized, the styrene-acrylic polymer segment is reacted with both reactive monomers, and a polyvalent carboxylic acid monomer and a polyvalent for forming a polyester segment. A method of forming a polyester segment by reacting an alcohol monomer;
(C) A method in which a polyester segment and a styrene-acrylic polymer segment are respectively preliminarily polymerized, and both reactive monomers are reacted with these to bond them; and (D) a polyester segment is polymerized in advance, A method of adding a styrene-acrylic polymerizable monomer to a polymerizable unsaturated group of a polyester segment, or reacting with a vinyl group in a styrene-acrylic polymer segment to bond them together.

  In this specification, the both reactive monomers are a group capable of reacting with a polyvalent carboxylic acid monomer and / or a polyhydric alcohol monomer for forming a polyester segment of a styrene-acryl-modified polyester resin, and a polymerizable unsaturated group. And a monomer having

The method (A) will be specifically described.
(1) A mixing step of mixing an unmodified polyester resin, an aromatic vinyl monomer and a (meth) acrylic acid ester monomer, and a bireactive monomer;
(2) A styrene-acrylic polymer segment can be formed at the end of the polyester segment by passing through a polymerization step of polymerizing the aromatic vinyl monomer and the (meth) acrylic acid ester monomer. In this case, the terminal hydroxyl group of the polyester segment and the carboxy group of both reactive monomers form an ester bond, and the vinyl group of both reactive monomers is the vinyl group of the aromatic vinyl monomer or (meth) acrylic acid monomer. To bond the styrene-acrylic polymer segments. Of the above synthesis methods, the method (A) is most preferred. According to this method, the styrene-acrylic polymer segment can be added to the end of the chain polyester segment.

  In the mixing step (1), it is preferable to heat. The heating temperature may be within a range in which an unmodified polyester resin, aromatic vinyl monomer, (meth) acrylic acid ester monomer and both reactive monomers can be mixed, and good mixing is obtained. Since polymerization control becomes easy, Preferably it is 80-200 degreeC, More preferably, it is 90-180 degreeC.

  Of unmodified polyester resin, aromatic vinyl monomer, (meth) acrylic acid ester monomer and both reactive monomers, the proportion of aromatic vinyl monomer and (meth) acrylic acid ester monomer used is the resin used The total ratio of the aromatic vinyl monomer and the (meth) acrylic acid ester monomer when the total mass of the material, that is, the total mass of the four members is 100 mass%, is preferably 3 to 35 mass%. More preferably, it is 5-30 mass%, Most preferably, it is 10-20 mass%. Since the total ratio of the aromatic vinyl monomer and the (meth) acrylic acid ester monomer to the total mass of the resin material used is within the above range, the toner has excellent high temperature elasticity, low temperature fixability and fixing. Separation can be demonstrated.

  Or as for the relative ratio of an aromatic vinyl monomer and a (meth) acrylic acid ester monomer, the glass transition point (Tg) calculated by the FOX formula represented by the following formula (A) is 35 to 80 ° C., The ratio is preferably in the range of 40 to 60 ° C.

  In the above formula (a), Wx is the weight fraction of monomer x, and Tgx is the glass transition point of the homopolymer of monomer x. In addition, in this specification, both reactive monomers shall not be used for calculation of a glass transition point.

  Among unmodified polyester resin, aromatic vinyl monomer, (meth) acrylic acid ester monomer, and both reactive monomers, the proportion of both reactive monomers used is the total mass of the resin material used, that is, the above four factors The ratio of both reactive monomers is 100% by mass or more and 5.0% by mass or less, and particularly 0.5% by mass or more and 3.0% by mass or less, when the total mass is 100% by mass. It is preferable.

(Aromatic vinyl monomers and (meth) acrylic acid ester monomers)
The aromatic vinyl monomer and (meth) acrylic acid ester monomer for forming the styrene-acrylic polymer segment have an ethylenically unsaturated bond capable of radical polymerization.

  Examples of the aromatic vinyl monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, and pn. -Butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4- Examples thereof include dimethylstyrene, 3,4-dichlorostyrene, and derivatives thereof. These aromatic vinyl monomers can be used alone or in combination of two or more.

  Examples of (meth) acrylic acid ester monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, Examples include hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like. These (meth) acrylic acid ester monomers can be used alone or in combination of two or more.

  As the aromatic vinyl monomer for forming the styrene-acrylic polymer segment, it is preferable to use a large amount of styrene or a derivative thereof from the viewpoint of obtaining excellent chargeability and image quality characteristics. Specifically, the amount of styrene or its derivative used is the total amount of monomers used to form the styrene-acrylic polymer segment (total amount of aromatic vinyl monomer and (meth) acrylic acid ester monomer). On the other hand, it is preferable that it is 50 mass% or more, and it is more preferable that it is 60-90 mass%.

(Amotropic monomer)
As the both reactive monomers for forming the styrene-acrylic polymer segment, a group capable of reacting with the polyvalent carboxylic acid monomer and / or the polyhydric alcohol monomer for forming the polyester segment and a polymerizable unsaturated group are used. Any monomer may be used, and specifically, acrylic acid, methacrylic acid, fumaric acid, maleic acid, maleic anhydride and the like can be used. In the present invention, it is preferable to use acrylic acid and methacrylic acid as both reactive monomers.

(Polyester resin)
The polyester resin used for producing the styrene-acrylic modified polyester resin according to the present invention is obtained by polycondensation reaction in the presence of an appropriate catalyst using polyvalent carboxylic acid monomer (derivative) and polyhydric alcohol monomer (derivative) as raw materials It is manufactured. Specifically, the polyester resin has a polycarboxylic acid monomer (derivative) and a polyhydric alcohol monomer (derivative) at a temperature of 180 to 250 ° C. in an inert gas atmosphere, if necessary, using an esterification catalyst. And can be produced by condensation polymerization for 6 to 10 hours. Examples of the esterification catalyst include metal compounds such as tin catalyst, titanium catalyst, antimony trioxide, zinc acetate, and germanium dioxide. From the viewpoint of the reaction efficiency of the esterification reaction in the synthesis of the polyester, a tin catalyst is preferable. As the tin catalyst, dibutyltin oxide, tin octylate, tin dioctylate, salts thereof and the like are preferably used. In the present invention, since a carboxylic acid having a non-aromatic carbon-carbon unsaturated bond is used, it is preferable to use a radical polymerization inhibitor. As the radical polymerization inhibitor, 4-t-butylcatechol and the like are preferable.

  As polyvalent carboxylic acid monomer derivatives, alkyl esters, acid anhydrides and acid chlorides of polyvalent carboxylic acid monomers can be used. As polyhydric alcohol monomer derivatives, ester compounds of polyhydric alcohol monomers and hydroxycarboxylic acids are used. Can be used.

  Examples of the polyvalent carboxylic acid monomer include oxalic acid, succinic acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, Fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucic acid, phthalic acid , Isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o-phenylenediglycolic acid , Diphenylacetic acid, diphenyl-p, p ′ Divalent carboxylic acids such as dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracene dicarboxylic acid, dodecenyl succinic acid; trimellitic acid, pyromellitic Examples thereof include trivalent or higher carboxylic acids such as acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, and pyrenetetracarboxylic acid. As the polyvalent carboxylic acid monomer, an aliphatic unsaturated dicarboxylic acid such as fumaric acid, terephthalic acid, maleic acid or mesaconic acid is preferably used. In particular, the aliphatic unsaturated dicarboxylic acid represented by the general formula (A) is used. It is preferable to use an acid. In the present invention, an anhydride of a dicarboxylic acid such as maleic anhydride can also be used. These polyvalent carboxylic acid monomers may be used alone or in the form of a mixture of two or more.

  The proportion of the aliphatic unsaturated dicarboxylic acid in all the polyvalent carboxylic acid monomers is preferably 25 mol% or more and 75 mol% or less, and more preferably 30 mol% or more and 60 mol% or less. When the ratio of the aliphatic unsaturated dicarboxylic acid used is within the above range, the obtained styrene-acryl-modified polyester resin has an appropriate carboxyl group, and is modified with a substituent-containing compound, thereby providing a good release agent. Affinity, elasticity at high temperature, hot offset resistance and fixing separation can be exhibited.

  Examples of the polyhydric alcohol monomer include ethylene glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, octanediol, decanediol, dodecanediol, ethylene oxide adduct of bisphenol A, and propylene oxide adduct of bisphenol A. And dihydric alcohols such as glycerin, pentaerythritol, trimethylolpropane, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, tetraethylolbenzoguanamine, and sorbitol.

  The ratio of the polyhydric carboxylic acid monomer to the polyhydric alcohol monomer is preferably an equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] of the polyhydric alcohol monomer and the carboxyl group [COOH] of the polyhydric carboxylic acid. Is 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2.

  As the catalyst for synthesizing the polyester resin, various conventionally known catalysts can be used.

  The unmodified polyester resin for obtaining the styrene-acrylic modified polyester resin preferably has a glass transition point of 40 ° C. or higher and 70 ° C. or lower, more preferably 50 ° C. or higher and 65 ° C. or lower. When the glass transition point of the unmodified polyester resin is 40 ° C. or higher, the cohesive force in the high temperature region becomes appropriate for the polyester resin, and the occurrence of hot offset phenomenon during fixing is suppressed. Further, since the glass transition point of the unmodified polyester resin is 70 ° C. or less, sufficient melting can be obtained at the time of fixing, and a sufficient minimum fixing temperature can be ensured. When the weight average molecular weight is 1,500 or more, a cohesive force suitable for the entire binder resin is obtained, and the occurrence of a hot offset phenomenon during fixing is suppressed. Further, when the weight average molecular weight is 60,000 or less, it is possible to obtain a sufficient melting and secure a minimum fixing temperature, while suppressing occurrence of a hot offset phenomenon during fixing. The

  The unmodified polyester resin has a partially branched structure or a crosslinked structure formed by selecting a carboxylic acid valence or an alcohol valence as a polyvalent carboxylic acid monomer and / or a polyhydric alcohol monomer to be used. May be.

(Polymerization initiator)
In the polymerization step of polymerizing the aromatic vinyl monomer and the (meth) acrylic acid ester monomer, the polymerization is preferably performed in the presence of a radical polymerization initiator, and the timing of adding the radical polymerization initiator is particularly limited. However, it is preferably added after the mixing step in terms of easy control of radical polymerization.

  Various known polymerization initiators are preferably used as the polymerization initiator. Specifically, for example, hydrogen peroxide, acetyl peroxide, cumyl peroxide, -tert-butyl peroxide (di-t-butyl peroxide), propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichloro peroxide Benzoyl, bromomethylbenzoyl peroxide, lauroyl peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyl peroxycarbonate, tetralin hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, pertriphenylacetic acid- tert-hydroperoxide, formate-tert-butyl, peracetate-tert-butyl, perbenzoate-tert-butyl, perphenylacetate-tert-butyl, permethoxyacetate-tert-butyl, per-N- (3-toluyl) ) Palmitic acid-te peroxides such as t-butyl; 2,2′-azobis (2-aminodipropane) hydrochloride, 2,2′-azobis- (2-aminodipropane) nitrate, 1,1′-azobis (1 -Methylbutyronitrile-3-sodium sulfonate), 4,4'-azobis-4-cyanovaleric acid, poly (tetraethylene glycol-2,2'-azobisisobutyrate) and other azo compounds. It is done.

(Chain transfer agent)
In the polymerization process for polymerizing the aromatic vinyl monomer and the (meth) acrylic acid ester monomer, a commonly used chain transfer agent is used for the purpose of adjusting the molecular weight of the styrene-acrylic polymer segment. be able to. The chain transfer agent is not particularly limited, and examples thereof include alkyl mercaptans and mercapto fatty acid esters. The chain transfer agent is preferably mixed with the resin material in the mixing step.

  The addition amount of the chain transfer agent varies depending on the molecular weight and molecular weight distribution of the desired styrene-acrylic polymer segment. Specifically, the aromatic vinyl monomer, the (meth) acrylic acid ester monomer, and both reactive monomers It is preferable to add in the range of 0.1 to 5% by mass with respect to the total amount.

  The polymerization temperature in the polymerization step for polymerizing the aromatic vinyl monomer and the (meth) acrylic acid ester monomer is not particularly limited, and the polymerization between the aromatic vinyl monomer and the (meth) acrylic acid ester monomer and the polyester It can select suitably in the range in which the coupling | bonding to resin advances. For example, the polymerization temperature is preferably 85 ° C. or higher and 125 ° C. or lower, more preferably 90 ° C. or higher and 120 ° C. or lower, and further preferably 95 ° C. or higher and 115 ° C. or lower.

  In the production of the styrene-acrylic modified polyester resin, it is practically preferable that volatile organic substances from the emulsion such as the amount of residual monomer after the polymerization step are suppressed to 1,000 ppm or less, more preferably 500 ppm or less, Preferably it is 200 ppm or less.

≪Polyester resin≫
The toner of the present invention contains a polyester resin in addition to the styrene-acryl-modified polyester resin. Here, the polyester resin is not particularly limited, but the same polyester resin as described in the above-mentioned section “Styrene-acrylic modified polyester resin” can be used. The polyester resin used for the production of the styrene-acryl-modified polyester resin and the polyester resin contained in the toner of the present invention may be the same or different.

  The mixing ratio of the styrene-acrylic modified polyester resin and the polyester resin is not particularly limited. Preferably, the styrene-acryl-modified polyester resin is contained in an amount of 3 to 35% by mass with respect to the total mass of the polyester resin and the styrene-acryl-modified polyester resin. More preferably, the styrene-acryl-modified polyester resin is contained in an amount of 5 to 30% by mass with respect to the total mass of the polyester resin and the styrene-acryl-modified polyester resin. Even more preferably, the styrene-acrylic modified polyester resin is contained in an amount of more than 5% by mass and 28% by mass or less based on the total mass of the polyester resin and the styrene-acrylic modified polyester resin. Particularly preferably, the styrene-acryl-modified polyester resin is contained in an amount of 10 to 20% by mass with respect to the total mass of the polyester resin and the styrene-acryl-modified polyester resin.

≪Toner≫
The toner of the present invention may be used as it is for a toner having a non-core / shell structure, or may be used for a core particle or a shell layer of a core / shell toner having a shell layer on the core particle surface. Good. Among these, the toner of the present invention is preferably used as it is for the core particles of a toner having a core / shell structure, or used for the core particles of a toner having a core / shell structure. More preferably. In the case of a toner having a core / shell structure, since the release agent is generally included in the core particles, the affinity for the release agent can be improved by using the toner of the present invention for the core particles. From the viewpoint of elasticity at high temperature, hot offset resistance and fixing separation property of the toner to be obtained.

  Hereinafter, an embodiment in which the toner of the present invention, which is a particularly preferred embodiment of the present invention, is used as the core particle of toner having a core / shell structure will be described in detail. However, the present invention is not limited to the following embodiment, and other embodiments can be similarly applied according to the following method.

(Shell layer)
The shell layer constituting the toner of the present invention is not particularly limited, and a resin (shell resin) generally used for a shell layer of a toner having a core / shell structure can be similarly used. Specific examples include styrene-acrylic modified polyester resins, styrene-acrylic resins, polyester resins, and urethane resins. Preferably, a polyester resin is used, and a polyester resin is more preferable. Polyester resins can be easily designed to have a low softening point while maintaining a high glass transition point (Tg) (excellent moldability), so a thin shell layer is formed to stabilize the low-temperature fixing performance by core particles. Can be expressed. In addition, when a styrene-acrylic modified polyester resin is used as the shell resin, the affinity of the core particles with the styrene-acrylic resin is increased while maintaining the high glass transition point and low softening point of the polyester resin. Even though it is a thin layer, a shell layer having a more uniform film thickness and a smooth surface can be formed. Therefore, both low-temperature fixability and heat-resistant storage stability are satisfied, and excellent chargeability is obtained.Since the shell layer is difficult to peel off, it is crushed even if it is stirred and stressed in the developing device. As a result, a high-quality image free from image noise can be obtained even in a high-function device such as a high-speed device.

  The styrene-acryl-modified polyester resin and the polyester resin can be the same as described above. Moreover, the said shell resin may be used independently or may be used with the form of 2 or more types of mixtures.

(Core particles)
In the present invention, the core particles contain at least a binder resin, and may contain a colorant, a release agent (wax), and a charge control agent as necessary. Here, the binder resin constituting the core particle is a styrene-acryl-modified polyester resin (modified styrene-acryl-modified polyester resin) in which a carboxyl group is modified with a substituent-containing compound, and a polyester resin, preferably a substituent group It contains a polyester resin obtained by modifying a carboxyl group with a compound. The mixing ratio of the modified styrene-acrylic modified polyester resin and the polyester resin is not particularly limited, but the modified styrene-acrylic modified polyester resin is the total amount of the binder resin (the total mass of the styrene-acrylic modified polyester resin and the polyester resin). ) To 5 to 30% by mass. Within this range, the toner can achieve both low-temperature fixability and fixing separation performance.

  The core particles preferably contain a modified styrene-acrylic modified polyester resin and a polyester resin as a binder resin, but may contain other resins in addition to these resins. In this case, the other resin is not particularly limited, and the same resin as that normally used as a binder resin for the toner is used. More specifically, unmodified styrene-acrylic modified polyester resin, styrene-acrylic resin, urethane resin and the like can be mentioned. Further, the content of the other resin in this case is not particularly limited as long as the effect of the present invention by the modified styrene-acryl modified polyester resin and the polyester resin is not impaired. For example, the content of other resins is preferably about 5 to 30% by mass with respect to the total amount of the binder resin.

(Unmodified styrene-acrylic modified polyester resin)
As the styrene-acrylic modified polyester resin constituting the core particle, the aforementioned styrene-acrylic modified polyester resin is used.

(Styrene-acrylic resin)
The polymerizable monomer used in the styrene-acrylic resin constituting the core particle of the present invention is an aromatic vinyl monomer and a (meth) acrylic acid ester monomer, and is ethylenically unsaturated capable of performing radical polymerization. Those having a bond are preferred. For example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, pn-butylstyrene, p-tert- Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4-dimethyl styrene, 3,4-dichloro Examples thereof include styrene and derivatives thereof. These aromatic vinyl monomers can be used alone or in combination of two or more.

  Examples of (meth) acrylic acid ester monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, Examples include hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like. These (meth) acrylic acid ester monomers can be used alone or in combination of two or more. Among these, it is preferable to use a combination of a styrene monomer, an acrylate monomer, and a methacrylate ester monomer.

  A third vinyl monomer can also be used as the polymerizable monomer. Examples of the third vinyl monomer include acid monomers such as acrylic acid, methacrylic acid, maleic anhydride, and vinyl acetate, acrylamide, methacrylamide, acrylonitrile, ethylene, propylene, butylene vinyl chloride, N-vinyl pyrrolidone, and butadiene. It is done.

  A polyfunctional vinyl monomer may be further used as the polymerizable monomer. Examples of the polyfunctional vinyl monomer include diacrylates such as ethylene glycol, propylene glycol, butylene glycol, and hexylene glycol, and dimethacrylates and trimethacrylates of tertiary alcohols such as divinylbenzene, pentaerythritol, and trimethylolpropane. Is mentioned. The copolymerization ratio of the polyfunctional vinyl monomer to the entire polymerizable monomer is usually 0.001 to 5% by mass, preferably 0.003 to 2% by mass, and more preferably 0.01 to 1% by mass. By using a polyfunctional vinyl monomer, a gel component insoluble in tetrahydrofuran is produced, but the proportion of the gel component in the whole polymer is usually 40% by mass or less, preferably 20% by mass or less.

  The glass transition point (Tg) of the binder resin constituting the core particle is preferably 40 ° C to 60 ° C. Similarly, the softening point of the binder resin constituting the core particle is preferably 80 ° C. to 110 ° C. When the glass transition point and softening point of the binder resin constituting the core particle are within the above ranges, the viscosity and elasticity of the toner can be within a preferable range, so that both low temperature fixability and fixing separation performance are satisfied. Can do.

  The measuring method of the glass transition point (Tg) and softening point of the binder resin constituting the core can be performed by the same method as the measuring method of the styrene-acrylic modified polyester resin.

(Method for producing styrene-acrylic resin)
The styrene-acrylic resin constituting the core particle of the present invention is preferably used in an emulsion polymerization method. Emulsion polymerization can be obtained by dispersing and polymerizing a polymerizable monomer such as styrene or acrylate in an aqueous medium. In order to disperse the polymerizable monomer in the aqueous medium, a surfactant is preferably used, and a polymerization initiator and a chain transfer agent can be used for the polymerization.

(Polymerization initiator)
The polymerization initiator used for the polymerization of the styrene-acrylic resin is not particularly limited, and known ones can be used, and the styrene-acrylic polymer segment of the styrene-acrylic modified polyester resin described above. The polymerization initiator used for the polymerization of can be used. As the polymerization initiator used for the polymerization, a water-soluble polymerization initiator is preferably used. Specifically, for example, hydrogen peroxide, acetyl peroxide, cumyl peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, Lauroyl oxide, ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyl peroxycarbonate, tetralin hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, pertriphenylacetic acid-tert-hydroperoxide, performic acid-tert -Butyl, peracetic acid-tert-butyl, perbenzoic acid-tert-butyl, perphenylacetic acid-tert-butyl, permethoxyacetic acid-tert-butyl, per-N- (3-toluyl) palmitic acid-tert-butyl, etc. Peroxides; 2, '-Azobis (2-aminodipropane) hydrochloride, 2,2'-azobis- (2-aminodipropane) nitrate, 1,1'-azobis (sodium 1-methylbutyronitrile-3-sulfonate), Azo compounds such as 4,4′-azobis-4-cyanovaleric acid and poly (tetraethylene glycol-2,2′-azobisisobutyrate).

(Chain transfer agent)
In the production of the styrene-acrylic resin of the present invention, a chain transfer agent may be added together with the polymerizable monomer. The molecular weight of the polymer can be controlled by adding a chain transfer agent. As the chain transfer agent, known ones can be used. For example, the chain transfer agent used for the polymerization of the styrene-acrylic polymer segment of the styrene-acryl-modified polyester resin described above can be used. And mercapto fatty acid esters. The addition amount of the chain transfer agent varies depending on the desired molecular weight and molecular weight distribution, but specifically, it is preferably added in the range of 0.1 to 5% by mass with respect to the polymerizable monomer.

(Surfactant)
When a styrene-acrylic resin is dispersed in an aqueous medium and polymerized by an emulsion polymerization method, a dispersion stabilizer is usually added to prevent aggregation of the dispersed droplets. As the dispersion stabilizer, a known surfactant can be used, and a dispersion stabilizer selected from a cationic surfactant, an anionic surfactant, a nonionic surfactant and the like can be used. Two or more of these surfactants may be used in combination. The dispersion stabilizer can also be used in a dispersion liquid such as a colorant and an offset preventing agent.

  Specific examples of the cationic surfactant include dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like.

  Specific examples of nonionic surfactants include dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, norylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, styrylphenyl poly Examples thereof include oxyethylene ether and monodecanoyl sucrose.

  Specific examples of the anionic surfactant include aliphatic soaps such as sodium stearate and sodium laurate, sodium lauryl sulfate, sodium dodecylbenzene sulfonate, polyoxyethylene (2) sodium lauryl ether sulfate and the like. it can.

  If necessary, a colorant, a release agent (wax), and a charge control agent can be added to the toner of the present invention.

(Coloring agent)
The colorant used in the toner of the present invention is not particularly limited, and carbon black, a magnetic material, a dye, a pigment, and the like can be arbitrarily used. As the carbon black, channel black, furnace black, acetylene black, Thermal black, lamp black, etc. are used. As the magnetic material, ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, and compounds of ferromagnetic metals such as ferrite and magnetite can be used. These can be used alone or in combination of two or more.

  Although it does not restrict | limit especially as dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc. can be used, and mixtures thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 48: 3, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 166, 177, 178, 222, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 15: 4, 60, and the like, and a mixture thereof can also be used. The number average primary particle diameter varies depending on the type, but is preferably about 10 to 200 nm. These can be used alone or in combination of two or more.

(Release agent (wax))
The toner of the present invention can contain a release agent (wax). The release agent (wax) is not particularly limited. For example, hydrocarbon waxes such as low molecular weight polyethylene wax, low molecular weight polypropylene wax, Fischer-Tropsch wax, microcrystalline wax, paraffin wax, carnauba wax, penta Examples thereof include ester waxes such as erythritol behenate, behenate behenate and behenyl citrate. These can be used alone or in combination of two or more.

  The content of the release agent (wax) is not particularly limited, but is preferably 1 to 20% by mass, more preferably 2 to 18% by mass, and even more preferably 3 to 15% by mass with respect to the total mass of the resin particles. Degree.

  Further, the melting point of the wax is preferably 50 to 95 ° C. from the viewpoint of low-temperature fixability and releasability of the toner in electrophotography.

(Charge control agent)
As the charge control agent constituting the charge control agent particles, various known ones that can be dispersed in an aqueous medium can be used. Specific examples include nigrosine dyes, naphthenic acid or higher fatty acid metal salts, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof.

  The charge control agent particles preferably have a number average primary particle diameter of about 10 to 500 nm in a dispersed state.

≪Toner particles (toner base particles) ≫
The toner of the present invention can be used as toner particles as it is, but it is usually preferable to add an external additive. In the present specification, toner particles having a core-shell structure having a shell layer on the surface of the core particles are also referred to as “toner base particles”. In the present specification, “toner” means an aggregate of toner particles.

  First, the average circularity of the toner particles used in the present invention will be described. The average circularity of the toner particles used in the present invention is preferably from 0.850 to 0.990.

Here, the average circularity of the toner particles is a value measured using “FPIA-2100” (manufactured by Sysmex).

  Specifically, the toner particles are moistened with an aqueous surfactant solution, and ultrasonic dispersion is performed for 1 minute. After dispersion, HPFP detection is performed in the measurement condition HPF (high magnification imaging) mode using “FPIA-2100”. Measurement is performed at appropriate concentrations of several thousand to 10,000. Within this range, reproducible measurement values can be obtained. The circularity is calculated by the following formula.

  The average circularity is an arithmetic average value obtained by adding the circularity of each particle and dividing by the total number of particles measured.

(Particle size of toner particles)
Next, the particle size of the toner particles used in the present invention will be described. The particle diameter of the toner particles used in the present invention is not particularly limited, but it is preferably 3 μm or more and 10 μm or less in volume-based median diameter (D ₅₀ ).

  By setting the volume reference median diameter in the above range, for example, it is possible to faithfully reproduce a very minute dot image at a level of 1200 dpi (dpi; number of dots per inch (2.54 cm)).

The volume-based median diameter (D ₅₀ ) of the toner particles can be measured and calculated using, for example, a device in which a computer system for data processing is connected to “Multisizer 3 (manufactured by Beckman Coulter)”.

  As a measurement procedure, 0.02 g of toner particles are used in 20 ml of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). After being blended, ultrasonic dispersion is performed for 1 minute to prepare a toner particle dispersion. This toner particle dispersion is poured into a beaker containing ISOTON II (manufactured by Beckman Coulter) in a sample stand with a pipette until the measured concentration becomes 5 to 10%, and the measuring machine count is set to 25,000. taking measurement. The aperture size of the multisizer 3 is 100 μm.

(Toner softening point)
The softening point of the toner of the present invention is preferably 90 ° C to 115 ° C. When the softening point of the toner is within this range, preferable low-temperature fixability can be obtained.

  The softening point can be measured by the above-described method, that is, “Flow Tester CFT-500D” (manufactured by Shimadzu Corporation).

(Method for producing toner base particles)
In the toner of the present invention, toner base particles are obtained using a binder resin, if necessary, a colorant, and an internal additive such as wax, and an external additive is added to the toner base particles as necessary. By doing so, a toner can be manufactured.

  A preferred embodiment of a method for producing toner base particles used in the present invention will be described below.

  The toner base particles used in the present invention are particles containing at least a binder resin and a colorant, and constitute a base of toner particles used for electrophotographic image formation. These are called colored particles.

  Examples of the method for producing the toner base particles of the present invention include a suspension polymerization method, an emulsion aggregation method, and other known methods. The emulsion aggregation method is preferably used. According to this emulsion aggregation method, the toner particles can be easily reduced in size from the viewpoint of production cost and production stability.

  Here, the emulsion aggregation method refers to a dispersion of binder resin particles (hereinafter also referred to as “binder resin particles”) produced by emulsification, and, if necessary, particles of colorant (hereinafter referred to as “coloring”). In this method, toner particles are produced by mixing with a dispersion liquid (also referred to as “agent particles”), aggregating until a desired toner particle diameter is obtained, and further fusing the binder resin particles to control the shape. is there. Here, the binder resin particles may optionally contain a release agent, a charge control agent, and the like.

An example of using the emulsion aggregation method as a method for producing the toner is shown below.
(1) a step of preparing a dispersion in which colorant particles are dispersed in an aqueous medium;
(2) A step of preparing a dispersion in which binder resin particles containing an internal additive are dispersed in an aqueous medium as required;
(3) mixing the colorant particle dispersion and the binder resin particle dispersion to agglomerate and fuse the colorant particles and the binder resin particles to form toner particles;
(4) a step of filtering the toner particles from the dispersion system (aqueous medium) of the toner particles to remove the surfactant and the like;
(5) a step of drying the toner particles; and (6) a step of adding an external additive to the toner particles.

  As a method for dispersing the binder resin particles in the step (2), an emulsion polymer particle dispersion obtained by emulsion polymerization is preferably used. The binder resin particles may have a multilayer structure of two or more layers made of binder resins having different compositions. For the binder resin particles having such a structure, for example, those having a two-layer structure, a dispersion of resin particles is prepared by emulsion polymerization treatment (first-stage polymerization) according to a conventional method, and polymerization is started in this dispersion. An agent and a polymerizable monomer are added, and this system can be obtained by a technique of polymerization treatment (second stage polymerization).

  In the emulsion aggregation method, it is also possible to obtain toner particles having a core / shell structure. Specifically, toner particles having a core / shell structure are prepared by first binding resin particles for core particles and colorant particles. Then, core particles are prepared by agglomerating and fusing, and then the binder resin particles for the shell layer are added to the core particle dispersion to agglomerate and fuse the binder resin particles for the shell layer on the core particle surface. It can be obtained by forming a shell layer that coats the surface of the core particles.

(Process for producing core particles)
As a method for forming the core particle, it can be produced by a known method, but an emulsion aggregation method in which resin particles dispersed in an aqueous medium and colored particles are aggregated to form core particles is preferably used.

  When the core particles have a structure formed by agglomerating / fusing resin particles composed of a modified styrene-acrylic-modified polyester resin and a polyester resin, the core particles are usually formed by an emulsion aggregation method. When adopting the emulsion aggregation method, in detail, resin particles and colorant particles obtained by emulsifying and dispersing a polymerizable monomer in an aqueous medium and polymerizing, if necessary, an anti-offset agent such as wax, a charge control agent, magnetic powder, etc. The core particles may be formed by agglomeration / fusion in an aqueous medium together with other additives, or the polymerizable monomer is added in an aqueous medium in the presence of an emulsified anti-offset agent or charge control agent additive. The core particles may be formed by seed emulsion polymerization. The particle diameter of the resin particles is usually preferably in the range of 50 nm to 500 nm in terms of weight average particle diameter.

(Method for forming shell layer)
When the shell layer is uniformly formed on the surface of the core particle, it is preferable to employ an emulsion aggregation method. When the emulsion aggregation method is employed, an emulsion dispersion of shell particles can be added to an aqueous dispersion of core particles, and the shell particles can be aggregated / fused on the surface of the core particles.

  In particular, the toner of the present invention is a mixture of a dispersion liquid in which colorant particles are dispersed in an aqueous medium and a dispersion liquid in which binder resin particles are dispersed in an aqueous medium, whereby the colorant particles and the binder are mixed. It is preferably obtained by a process of aggregating and fusing the resin particles, that is, obtained by a production method such as an emulsion aggregation method.

  In the present invention, the “aqueous medium” refers to a medium comprising 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran, and alcohol-based organic solvents that do not dissolve the resulting resin are preferable.

(Surfactant)
A dispersion stabilizer is usually added to the aqueous medium in order to prevent aggregation of dispersed droplets. As the dispersion stabilizer, a known surfactant can be used, and a dispersion stabilizer selected from a cationic surfactant, an anionic surfactant, a nonionic surfactant and the like can be used. Two or more of these surfactants may be used in combination. The dispersion stabilizer can also be used in a dispersion liquid such as a colorant and an offset preventing agent.

  Specific examples of the cationic surfactant include dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl anonium bromide and the like.

  Specific examples of nonionic surfactants include dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, norylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, styrylphenyl poly Examples thereof include oxyethylene ether and monodecanoyl sucrose.

  Specific examples of the anionic surfactant include aliphatic soaps such as sodium stearate and sodium laurate, sodium lauryl sulfate, sodium dodecylbenzene sulfonate, polyoxyethylene (2) sodium lauryl ether sulfate and the like. it can.

(Dispersion of colorant)
A dispersion of colorant particles can be prepared by dispersing a colorant in an aqueous medium. The dispersion treatment of the colorant is preferably performed in a state where the surfactant concentration in the aqueous medium is equal to or higher than the critical micelle concentration because the colorant is uniformly dispersed. A known disperser can be used as the disperser used for the dispersion treatment of the colorant. Moreover, as a surfactant which can be used, a publicly known thing can be used.

  The particle diameter of the colorant particles in the step (1) of adjusting the dispersion is preferably 10 to 300 nm in terms of volume-based median diameter.

(Measurement of dispersed particle size in colorant dispersion)
The dispersion particle diameter of the colorant particles in the aqueous medium is a volume average particle diameter, that is, a median diameter on a volume basis. This median diameter is measured using a microtrack particle size distribution measuring apparatus “UPA-150” (manufactured by Nikkiso Co., Ltd.). It is a measured value.

  Ion exchange water is put into the measurement cell, and the zero point adjustment is performed.

(Aggregation / fusion process)
Next, the step of aggregating and associating resin particles and colorant particles in the emulsion aggregation method will be described.

  In the aggregation process, an aqueous dispersion of resin particles is mixed with a dispersion of colorant particles and, if necessary, wax particles, charge control agent particles, and other toner constituent particles to prepare an aggregation dispersion. Then, it is aggregated and fused in an aqueous medium to form a dispersion of colored particles.

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

  In the flocculation step, it is preferable that the standing time (time until heating is started) to be left after adding the flocculant is as short as possible. That is, after adding the flocculant, it is preferable to start heating the flocculating dispersion liquid as quickly as possible so as to be equal to or higher than the glass transition point of the resin composition. The reason for this is not clear, but the agglomeration state of the particles fluctuates with the passage of the standing time, and there is a possibility that the particle size distribution of the obtained toner particles becomes unstable or the surface property fluctuates. Because there is. The standing time is usually within 30 minutes, preferably within 10 minutes.

  In the aggregation step, it is preferable to quickly raise the temperature by heating, and the rate of temperature rise is preferably 1 ° C./min or more. The upper limit of the heating rate is not particularly limited, but is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to rapid progress of fusion. Furthermore, it is important to continue the fusion by holding the temperature of the aggregation dispersion liquid for a certain period of time after the aggregation dispersion liquid reaches a temperature equal to or higher than the glass transition temperature. Thereby, the growth and fusion of the colored particles can be effectively advanced, and the durability of the toner particles finally obtained can be improved.

(External additive)
In the present invention, an external additive can be added for the purpose of improving the fluidity and charging characteristics of the toner.

  Examples of the external additive used in the present invention include inorganic oxide fine particles such as silica fine particles, alumina fine particles, and titanium oxide (thiania) fine particles, inorganic stearate compound fine particles such as aluminum stearate fine particles and zinc stearate fine particles, or Examples include inorganic fine particles such as inorganic titanate compound fine particles such as strontium titanate and zinc titanate.

  These inorganic fine particles are preferably those subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil, or the like from the viewpoint of heat-resistant storage stability and environmental stability.

  The addition amount of the external additive is not particularly limited, but is preferably 0.05 to 5 parts by mass, more preferably about 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner base particles. Various external additives may be used in combination.

  Examples of the method for adding the external additive include a dry method in which the external additive is added in powder form to the dried toner base particles. Examples of the mixing device include mechanical mixing devices such as a Henschel mixer and a coffee mill. It is done.

(Developer)
The toner of the present invention can be used as a two-component developer composed of a carrier and a toner, or as a non-magnetic one-component developer composed only of a toner.

  Carriers that are magnetic particles used when used as a two-component developer are conventionally known materials such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead. It is possible to use. Among these, ferrite particles are preferable. Further, as the carrier, a coated carrier in which the surface of the magnetic particles is coated with a coating agent such as a resin, a resin dispersion type carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used. The carrier has a volume average particle size of preferably 15 to 100 μm, more preferably 25 to 80 μm.

(Image forming device)
An image forming apparatus in which the toner of the present invention is used includes an electrostatic latent image carrier (typically an electrophotographic photoreceptor, hereinafter simply referred to as a photoreceptor), and charging means, exposure means, and toner. Developing means using a developer, and transfer means for transferring a toner image formed by the developing means to a transfer material via an intermediate transfer member. In particular, it is effective to use for color image forming devices that sequentially transfer the toner images on the photosensitive member to the intermediate transfer member, tandem type color image forming devices in which a plurality of photosensitive members for each color are arranged in series on the intermediate transfer member, etc. It is.

  The effect of this invention is demonstrated using a following example and a comparative example. However, the technical scope of the present invention is not limited to the following examples. In the following, unless otherwise specified, “part” and “%” mean “part by mass” and “% by mass”, respectively.

Production Example 1: Synthesis of polyester resin [A1] In a 10-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, 500 parts by mass of bisphenol A propylene oxide 2 mol adduct, terephthalic acid 117 parts by mass, 82 parts by mass of fumaric acid, and 2 parts by mass of tin octylate as an esterification catalyst were put into a polycondensation reaction at 230 ° C. for 8 hours and cooled to 35 ° C. to obtain a polyester resin [A1]. . In addition, the weight average molecular weight of obtained polyester resin [A1] was 15000.

Production Example 2 Synthesis of Styrene-Acrylic Modified Polyester Resin [B1] 500 mass by mass of bisphenol A propylene oxide 2 mol adduct into a 10 liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple Parts, 117 parts by mass of terephthalic acid, 82 parts by mass of fumaric acid, and 2 parts by mass of tin octylate as an esterification catalyst were subjected to a polycondensation reaction at 230 ° C. for 8 hours, and further reacted at 8 kPa for 1 hour, up to 160 ° C. Cooled down. Next, to this reaction product, a mixture of 10 parts by mass of acrylic acid, 30 parts by mass of styrene, 7 parts by mass of butyl acrylate, and 10 parts by mass of di-t-butyl peroxide as a polymerization initiator was added by a dropping funnel. The solution was added dropwise over a period of time, and after the addition, the addition polymerization reaction was continued for 1 hour while maintaining the temperature at 160 ° C. Then, after heating up at 200 degreeC and hold | maintaining at 10 kPa for 1 hour, styrene-acryl modified polyester resin [B1] was obtained by removing acrylic acid, styrene, and butyl acrylate. In addition, the weight average molecular weight of the obtained styrene-acryl modified polyester resin [B1] was 15000.

Production Example 3: Synthesis of Styrene-Acrylic Modified Polyester Resin [B2] to [B7] Production Example 2 was the same as Production Example 2 except that the amounts of styrene and butyl acrylate were changed to the amounts shown in Table 1 below. According to the same method, styrene-acryl modified polyester resins [B2] to [B6] were obtained.

  In Production Example 2, the amounts of bisphenol A propylene oxide 2 mol adduct, terephthalic acid, fumaric acid and styrene were changed to the amounts shown in Table 1 below, and acrylic acid was not used. A styrene-acryl modified polyester resin [B7] was obtained in the same manner as in Production Example 2, except that 24 parts by mass of 2-ethylhexyl acrylate was used instead of butyl acrylate.

  The weight average molecular weights of the obtained styrene-acryl-modified polyester resins [B2] to [B7] were 14000 ([B2]), 14500 ([B3]), 14500 ([B4]), and 15000 ([ B5]), 14000 ([B6]) and 14700 ([B7]). In addition, “St-Ac content” in Table 1 below indicates the content (% by mass) of the styrene-acrylic copolymer in the styrene-acrylic modified polyester resin.

Production Example 4: Preparation of Polyester Resin Particle Dispersion [A1] 100 parts by mass of the polyester resin [A1] obtained in Production Example 1 above was pulverized with “Landel Mill Model: RM” (manufactured by Tokuju Kogakusha Co., Ltd.) The resultant was mixed with 638 parts by mass of the 0.26% by mass sodium lauryl sulfate solution and stirred with an ultrasonic homogenizer “US-150T” (manufactured by Nippon Seiki Seisakusho Co., Ltd.) for 30 minutes with V-LEVEL at 300 μA. A “polyester resin particle dispersion [A1]” in which polyester resin fine particles [A1] having a volume-based median diameter (D ₅₀ ) of 200 nm were dispersed was prepared.

Production Example 5: Preparation of styrene-acrylic modified polyester resin dispersions [B1] to [B7] 100 parts by mass of the styrene-acrylic modified polyester resin dispersions [B1] to [B7] obtained in Production Examples 2 and 3 above. , Respectively, pulverized with “Landel mill type: RM” (manufactured by Deoksugaku Kogyo Co., Ltd.), mixed with 638 parts by weight of a sodium lauryl sulfate solution having a concentration of 0.26% by mass prepared in advance, and stirred with an ultrasonic homogenizer “US- 150T "(manufactured by Nippon Seiki Seisakusho), V-LEVEL, 300 μA ultrasonically dispersed for 30 minutes, and volume-based median diameter (D ₅₀ ) of 200 nm. Styrene-acrylic modified polyester resin dispersions [B1] to [B1] to [B1] to [B1] B7] is dispersed in “Styrene-acrylic modified polyester resin fine particle dispersions [B1] to [B7]”. Is, was prepared.

Production Example 6: Preparation of Colorant Particle Dispersion (1) 90 parts by mass of sodium dodecyl sulfate was stirred and dissolved in 1600 parts by mass of ion-exchanged water. While stirring this solution, 420 parts by mass of carbon black “Mogal L” (manufactured by Cabot) is gradually added, and then dispersed using a stirrer “Claremix” (manufactured by M Technique). A colorant dispersion liquid (1) having particles of the colorant dispersed therein was prepared. The particle diameter (volume-based median diameter) of this dispersion was measured using a Microtrac particle size distribution analyzer “UPA-150” (manufactured by Nikkiso Co., Ltd.), and was 117 nm.

Production Example 7 Production of Release Agent Fine Particle Dispersion (W1) 10 parts of sodium dodecyl sulfate, 30 parts of paraffin wax (melting point: 73 ° C.), 80 parts of ion-exchanged water, homogenizer (manufactured by IKA, Ultra Turrax T50) Then, the mixture was sufficiently dispersed while being heated to 95 ° C., and then subjected to a dispersion treatment with a pressure discharge type homogenizer (manufactured by Gorin Co., Ltd., Gorin homogenizer) to prepare a release agent fine particle dispersion (W1). The number average particle diameter of the release agent fine particles in the obtained dispersion was 240 nm. Thereafter, ion exchange water was added to adjust the solid content concentration of the dispersion to 20%.

Production Example 8: Preparation of polymer [C1] having a functional group capable of reacting with a carboxyl group A 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple 100 parts by weight of the polyester resin [A1] obtained, 10 parts by weight of glycidyl acrylate, 500 ml of methyl ethyl ketone, and 0.5 parts by weight of an azo polymerization initiator were allowed to undergo a condensation polymerization reaction at 230 ° C. for 5 hours, up to 35 ° C. After cooling, methyl ethyl ketone was removed under reduced pressure to obtain a glycidyl polymer [C1] having a functional group capable of reacting with a carboxyl group.

Production Example 9: Production of polymer dispersion (C1) having a functional group capable of reacting with a carboxyl group 10 parts of sodium dodecyl sulfate, 20 parts of glycidyl polymer [C1] obtained in Production Example 8 above, and ion-exchanged water 80 The part was sufficiently dispersed while being heated to 95 ° C. with a homogenizer (IKA, Ultra Turrax T50), and then dispersed with a pressure discharge type homogenizer (Gorin, Gorin homogenizer) to prepare dispersion (C1). did. The number average particle diameter of the release agent fine particles in the obtained dispersion was 250 nm. Thereafter, ion exchange water was added to adjust the solid content concentration of the dispersion to 10%.

Example 1 Preparation of Toner 1 (Aggregation / fusion process)
In a reaction vessel equipped with a stirrer, a temperature sensor, and a cooling tube, the polyester resin particle dispersion (A1) produced in Production Example 4 is 324 parts by mass in terms of solid content, and the styrene-acrylic produced in Production Example 5 above. 81 parts by mass of the modified polyester resin particle dispersion (B1) in terms of solids, 10 parts by mass of the release agent fine particle dispersion (W1) prepared in Production Example 7 in terms of solids, and 2000 parts by mass of ion-exchanged water After the addition, the pH was adjusted to 10 by adding a 5 mol / liter sodium hydroxide aqueous solution.

Thereafter, 30 parts by mass of the colorant particle dispersion (1) prepared in Production Example 6 was added in terms of solid content. Next, an aqueous solution in which 60 parts by mass of magnesium chloride was dissolved in 60 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. Thereafter, the temperature was raised after being allowed to stand for 3 minutes, and the temperature of the system was raised to 80 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 80 ° C. In this state, the particle size of the associated particles was measured with “Multisizer 3” (manufactured by Beckman Coulter), and when the median diameter (D ₅₀ ) on the volume basis became 6.0 μm, 35 parts by mass of the polymer dispersion (C1) having a functional group capable of reacting with the produced carboxyl group was added and stirred at 80 ° C. for 1 hour to produce core particles. Thereafter, the dispersion (A1) of the polyester resin particles prepared in Production Example 4 was added in an amount of 45 parts by mass in terms of solid content over 30 minutes, and when the supernatant of the reaction solution became transparent, 190 parts by mass of sodium chloride was added. An aqueous solution dissolved in 760 parts by mass of ion-exchanged water was added. Thereafter, the temperature is raised and the mixture is heated and stirred in a state of 90 ° C. to advance the fusing of the particles, and the average circularity measuring device “FPIA-2100” (manufactured by Sysmex) is used (the number of detected HPFs). 4000) When the average circularity reaches 0.945, it is cooled to 30 ° C., and a dispersion of toner 1 (toner base particles) in which a shell layer made of a polyester resin [A1] is formed on the core particles is prepared. did.

(Washing / drying process)
The “dispersion of toner 1” prepared in the above aggregation and fusion process was subjected to solid-liquid separation with a centrifugal separator to form a wet cake of toner base particles. The wet cake was washed with ion-exchanged water at 35 ° C. until the electric conductivity of the filtrate reached 5 μS / cm with the centrifuge, and then transferred to “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.). Drying to 0.5% by mass gave toner base particles [1]. The obtained toner base particles [1] had a volume-based median diameter (D ₅₀ ) of 6.2 μm and a softening point of 105 ° C.

(External additive treatment process)
In the “toner base particle [1]” prepared in the above washing and drying step, 1% by mass of hydrophobic silica (number average primary particle size = 12 nm) and hydrophobic titania (number average primary particle size = 20 nm) 0.3 The “mass%” was added and mixed with a Henschel mixer to prepare “Toner 1”.

Examples 2 to 7: Preparation of Toners 2 to 7 In Example 1, instead of the styrene-acryl-modified polyester resin particle dispersion (B1), the styrene-acryl-modified polyester resin particle dispersion (B2) shown in Table 2 below. ) To (B7) were used, and “Toners 2 to 7” were produced in the same manner as in Example 1.

Comparative Example 1 Production of Toner 8 “Toner 8” was produced in the same manner as in Example 1 except that the styrene-acryl-modified polyester resin particle dispersion (B1) was not used.

Examples 8 to 12: Preparation of toners 9 to 13 In Example 3, the mixing ratio of the styrene-acryl-modified polyester resin particle dispersion (B3) and the polyester resin particles (A1) was changed to the following Table 2. Except that, “Toners 9 to 13” were produced in the same manner as in Example 3.

Comparative Example 2: Preparation of Toner 14 “Toner 14” was prepared in the same manner as in Example 1 except that the polymer dispersion liquid (C1) having a functional group capable of reacting with a carboxyl group was not added. did.

≪Evaluation method≫
(1) Low-temperature fixing characteristics Image evaluation was performed by sequentially loading the developer prepared above into a developing device of a commercially available color multifunction peripheral “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies, Inc.). . In addition, modification was made so that the fixing temperature, the toner adhesion amount, and the system speed could be set freely. NPi high quality paper 128g / m ² (manufactured by Nippon Paper Industries Co., Ltd.) was used as the evaluation paper, and a solid image with a toner adhesion amount of 11.3g / m ² was fixed at a fixing speed of 300mm / sec. The fixing lower limit temperature at which a cold offset does not occur was evaluated when fixing was performed at a level of 5 ° C. at a temperature lower than the belt by 20 ° C. The lower the fixing minimum temperature, the better the fixing property.

Criteria ◎: Lower fixing temperature is 150 ° C. or lower ○: Lower fixing temperature is 165 ° C. or lower ×: Lower fixing temperature is 170 ° C. or higher (2) Fixing separation property The surface temperature of the fixing heat roller is 180 ° C. On the other hand, the separability between the image-side fixing roller (heating roller) and the paper when an A4 size image having a solid black belt-like image having a width of 5 cm in the vertical direction was conveyed by vertical feeding was determined according to the following criteria.

Criteria ◎: Paper separates from fixing roller without curling ○: Paper separates from fixing roller and separation claw, but almost no separation claw marks remain on image △: Paper separates from fixing roller and separation claw However, separation claw marks remain on the image. X: Paper is wound around the fixing roller and cannot be separated from the fixing roller.

  As is apparent from the results in Table 3, it can be seen that the toners 1 to 7 and 9 to 13 of the present invention are superior in both the low temperature fixing property and the fixing separation property as compared with the comparative toners 8 and 14.

Claims (5)

An electrostatic charge image developing toner containing a polyester resin and a styrene-acrylic modified polyester resin,
The carboxyl group present in the styrene-acryl-modified polyester resin is modified with a compound having at least one substituent selected from the group consisting of an oxazoline group, a glycidyl group, an aziridine group, and a carbodiimide group. Toner for developing electrostatic images.   The electrostatic charge according to claim 1, wherein the carboxyl group present in the polyester resin is modified with a compound having at least one substituent selected from the group consisting of an oxazoline group, a glycidyl group, an aziridine group and a carbodiimide group. Toner for image development.   The electrostatic image developing toner according to claim 1 or 2, wherein a content ratio of the styrene-acrylic copolymer in the styrene-acrylic modified polyester resin is 5 to 30% by mass.   The electrostatic charge according to any one of claims 1 to 3, wherein the styrene-acryl-modified polyester resin is contained in an amount of 5 to 30% by mass with respect to a total mass of the polyester resin and the styrene-acryl-modified polyester resin. Toner for image development.   The electrostatic image developing toner according to claim 1, wherein the compound having a substituent is a compound having two or more substituents.