JP2020085971A - Method for producing toner for electrostatic charge image development - Google Patents

Abstract

To provide a method for producing a toner for electrostatic charge image development capable of obtaining a toner for electrostatic charge development which has high coloring power, and is excellent in low temperature fixability and hot off-set resistance.SOLUTION: A method for producing a toner for electrostatic charge image development includes a step of melt-kneading at least a binder resin, a release agent and a coloring agent, in which the binder resin contains a crystalline polyester-based resin, the coloring agent is carbon black having a DBP oil absorption amount of 25 mL/100 g or more and 45 mL/100 g or less, and a content of the coloring agent is 8 pts.mass or more and 20 pts.mass or less to 100 pts.mass of the binder resin.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a toner for developing electrostatic images.

In the field of electrophotographic toner, in recent years, a toner having excellent low-temperature fixability has been demanded from the viewpoint of speeding up of a printing apparatus and energy saving. The crystalline polyester has crystallinity and contributes to the improvement of low-temperature fixability, but since the melt viscosity decreases at the time of fixing, compatibility with hot offset resistance is also required at the same time.
Patent Document 1 discloses that in an emulsion aggregation method toner, an amorphous polyester and a resin containing carbon black are neutralized in the presence of an alkali in an aqueous medium and then emulsified, followed by aggregation and fusion. This is a method for producing a black toner, in which low-temperature fixing is performed by setting the mass ratio [water/resin] of water and resin at the time of neutralization, the BET specific surface area of carbon black, the pH, and the DBP oil absorption to a specific range. It is described that a black toner for electrophotography which is excellent in image density and chargeability in addition to the property can be proposed.

In Patent Document 2, in the black toner, the peak temperature of the loss elastic modulus and the storage elastic modulus are controlled within a certain range, and the average primary particle diameter of the carbon black in the toner is set to 14 to 60 nm, whereby blocking resistance is increased. Properties, storage stability under high temperature environment, low temperature fixability, high temperature offset resistance, development stability, 3 environmental stability, transferability, and black toner that can stably obtain high-definition and high-quality images It is described that the above can be proposed.

Patent Document 3 discloses a toner obtained by a melt-kneading and pulverization method, in which a styrene-acrylic resin (A) having a relatively low weight average molecular weight that does not contain a carboxyl group and a glycidyl group and a relatively high weight average that contains a carboxyl group and a glycidyl group. A method for producing a kneading and pulverizing toner is described, which comprises at least a binder resin containing a styrene-acrylic resin (B) having a molecular weight, and a colorant. It is described that a toner excellent in hot offset resistance can be obtained without impairing the above.

JP, 2005-125408, A JP, 2003-84497, A JP, 2011-7863, A

The toners described in any of Patent Documents 1 to 3 are not sufficient as a design that achieves both low temperature fixability and hot offset resistance while maintaining high tinting strength. Although it is widely known that crystalline polyester is added as a binder resin for low-temperature fixability, the addition of crystalline polyester as a binder resin causes a decrease in viscosity of melted and kneaded toner in a pulverized toner, resulting in a colorant. However, there is a problem in that it is difficult to achieve compatibility with hot offset resistance as well as causing a decrease in dispersion. Further, for high coloring, it is important to contain a large amount of a colorant and to improve the dispersibility of the colorant in the toner. However, when a large amount of carbon black is added, the melt viscosity of the toner is increased due to the filler effect. However, there is a problem in that it is difficult to achieve compatibility with low temperature fixability.
The present invention relates to a method for producing an electrostatic charge image developing toner, which has a high tinting strength, is excellent in low-temperature fixability, and is also excellent in hot offset resistance.

The present inventors have used a crystalline polyester resin as a binder resin and a specific DBP (dibutyl phthalate) oil absorption amount as a colorant in a method for producing a toner for electrostatic image development by a pulverization method. By using a specific amount of carbon black with respect to the binder resin, the above-mentioned problems are solved, high colorability, and a toner for electrostatic image development having excellent low-temperature fixability and hot offset resistance is obtained. I found that I can be.
The present invention is a method for producing an electrostatic charge image developing toner, which has a step of melt-kneading at least a binder resin, a release agent, and a colorant, wherein the binder resin contains a crystalline polyester resin. The coloring agent is carbon black having a DBP oil absorption of 25 mL/100 g or more and 45 mL/100 g or less, and the content of the coloring agent is 8 parts by mass or more and 20 parts by mass or more with respect to 100 parts by mass of the binder resin. The following relates to a method for producing a toner for developing an electrostatic image.

According to the present invention, it is possible to provide a method for producing an electrostatic charge image developing toner, which has a high tinting strength, is excellent in low-temperature fixability, and is excellent in hot offset resistance. it can.

[Method for producing toner for developing electrostatic image]
The method for producing an electrostatic charge image developing toner of the present invention (hereinafter, also simply referred to as “toner”) is a method for producing an electrostatic charge image developing toner, which comprises a step of melt-kneading at least a binder resin, a release agent, and a colorant. In the production method, the binder resin contains a crystalline polyester resin, the colorant is carbon black having a DBP oil absorption of 25 mL/100 g or more and 45 mL/100 g or less, and the content of the colorant is Is 8 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.
By the above method, a toner for developing an electrostatic charge image having high tinting strength, excellent low-temperature fixability, and excellent hot offset resistance can be obtained.

The present technology is characterized in that, in a toner obtained by a pulverization method, a specific amount of carbon black (CB) having a specific DBP oil absorption amount is used as a colorant, and melt kneading is performed with a binder resin containing at least a crystalline polyester resin. Is. The following is considered about the mechanism of excellent low-temperature fixability and hot offset resistance while achieving high coloring by this method.
When a crystalline polyester resin is added for low temperature fixing, the melt viscosity is lowered. Since carbon black has a smaller primary particle size than other organic pigments and is hard to be loosened, it is considered that the conventional method causes a poor dispersion due to a decrease in melt viscosity.
On the other hand, since the carbon black having a relatively low oil absorption used in the present invention has a low particle structure, it is difficult to form a secondary aggregate even in a resin having a low viscosity, and the carbon black is dispersed in the toner. It is thought that it is easy to maintain. Further, even when the amount of carbon black added is increased, due to the structure of the low structure, the interface in contact with the resin is small and the interaction between the carbon black and the resin is less likely to occur, resulting in an increase in viscosity due to the filler effect with the resin. It is difficult, and we believe that inhibition of low-temperature fixability can be suppressed.
On the other hand, it is considered that the hot offset resistance is affected not by the increase in resin viscosity due to the filler effect but by the action with the release agent derived from the particle structure of carbon black. That is, when a large amount of general high-structure carbon black is added, a part of the release agent is adsorbed by the carbon black during fixing, and the exposure to the image surface is hindered, so that a sufficient release effect cannot be obtained. On the other hand, in the case of low structure carbon black, even if the addition amount is large, the adsorption of the release agent to carbon is small and a sufficient release effect can be obtained, so that both low temperature fixing property and hot offset resistance can be achieved. It is estimated that it will be possible.

Definitions of various terms in the present specification are shown below.
The crystalline index determines whether the resin is crystalline or amorphous. The crystallinity index is defined as the ratio between the softening point of the resin and the maximum peak temperature of the endotherm (softening point (°C)/maximum peak temperature of the endotherm (°C)) in the measuring method described in Examples described later. The crystalline resin has a crystallinity index of 0.6 or more and 1.4 or less. The amorphous resin has a crystallinity index of less than 0.6 or more than 1.4. The crystallinity index can be appropriately adjusted according to the type and ratio of the raw material monomers, and the production conditions such as reaction temperature, reaction time, and cooling rate.
In the specification, as the carboxylic acid component of the polyester resin, not only the compound but also an anhydride that decomposes to form an acid during the reaction, and an alkyl ester of each carboxylic acid (having 1 to 3 carbon atoms in the alkyl group) Is also included.
"Bisphenol A" is "2,2-bis(4-hydroxyphenyl)propane".
“(Meth)acrylic acid” means at least one selected from methacrylic acid and acrylic acid, and the same applies to (meth)acrylate and (meth)acryloyl groups.
The “volume median particle diameter D ₅₀ ”is a particle diameter at which the cumulative volume frequency calculated by the volume fraction becomes 50% when calculated from the smaller particle diameter.
The coefficient of variation of particle size distribution (hereinafter, also simply referred to as “CV value”) is a value represented by the following formula. The volume average particle size in the following formula is the particle size obtained by multiplying the particle size measured on a volume basis by the ratio of particles having that particle size value and dividing the value obtained by the number of particles. is there.
CV value (%)=[standard deviation of particle size distribution (μm)/volume average particle size (μm)]×100

A method for producing a toner according to an embodiment of the present invention includes, for example, a step of melt-kneading at least a binder resin, a release agent, and a colorant (hereinafter, also referred to as “step 1”) for electrostatic image development. A method for producing a toner, wherein the binder resin contains a crystalline polyester resin, the colorant is carbon black having a DBP oil absorption of 25 mL/100 g or more and 45 mL/100 g or less, and The content is 8 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.
Further, it is preferable to have the following step 2 following the above step 1.
Step 2: A step of pulverizing and classifying the melt-kneaded product obtained in Step 1 to obtain toner particles.
Hereinafter, the present invention will be described by taking the embodiment as an example.

<Step 1>
The method for producing a toner for developing an electrostatic image of the present invention has a step of melt-kneading at least a binder resin, a release agent, and a colorant. The toner raw material containing the binder resin, the release agent, and the colorant is preferably mixed in advance with a Henschel mixer, a ball mill or the like and then supplied to the kneader.

[Binder resin]
<<Crystalline polyester resin>>
Examples of the crystalline polyester resin (hereinafter, also referred to as “resin C”) include a crystalline polyester resin and a modified crystalline polyester resin. Examples of the modified crystalline polyester-based resin include a urethane-modified crystalline polyester-based resin in which a polyester resin is modified with a urethane bond, an epoxy-modified crystalline polyester-based resin in which a polyester resin is modified with an epoxy bond, and a polyester resin segment. And a crystalline composite resin containing an addition polymerization resin segment.
Among these, a crystalline polyester resin or a crystalline composite resin containing a polyester resin segment and an addition polymerization resin segment is preferable, and a crystalline composite resin containing a polyester resin segment and an addition polymerization resin segment is more preferable.

(Crystalline polyester resin)
The crystalline polyester resin is, for example, a polycondensate of an alcohol component and a carboxylic acid component.
The alcohol component preferably comprises an aliphatic diol, more preferably an α,ω-aliphatic diol.
The carbon number of the α,ω-aliphatic diol is preferably 2 or more, more preferably 4 or more, still more preferably 6 or more, still more preferably 9 or more, from the viewpoint of obtaining a toner having excellent low-temperature fixability. , Preferably 20 or less, more preferably 16 or less, still more preferably 15 or less, still more preferably 14 or less.
Examples of the α,ω-aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol and 1,14-tetradecanediol Can be mentioned. Among these, 1,10-decanediol and 1,12-dodecanediol are preferable.

The content of the α,ω-aliphatic diol in the alcohol component is preferably 80 mol% or more, more preferably 85 mol% or more, further preferably 90 mol% or more, still more preferably 95 mol% or more, And it is 100 mol% or less, more preferably 100 mol%.

The alcohol component may contain another alcohol component different from the α,ω-aliphatic diol. Examples of other alcohol components include aliphatic diols other than α,ω-aliphatic diols such as 1,2-propylene glycol and neopentyl glycol; alkylene oxide addition of aromatic diols such as bisphenol A alkylene oxide adducts. Substances: trivalent or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane. These alcohol components may use 1 type(s) or 2 or more types.

The carboxylic acid component preferably comprises an aliphatic dicarboxylic acid, more preferably an α,ω-aliphatic dicarboxylic acid.
The number of carbon atoms of the aliphatic dicarboxylic acid, preferably α,ω-aliphatic dicarboxylic acid, is preferably 4 or more, more preferably 6 or more, still more preferably 8 or more, from the viewpoint of obtaining a toner having excellent low-temperature fixability. It is preferably 9 or more, and preferably 20 or less, more preferably 16 or less, still more preferably 14 or less, even more preferably 12 or less.
Examples of the aliphatic dicarboxylic acid include fumaric acid, sebacic acid, dodecanedioic acid and tetradecanedioic acid. These may use 1 type(s) or 2 or more types. Of these, sebacic acid is preferred.

The amount of the aliphatic dicarboxylic acid in the carboxylic acid component is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and 100 It is at most mol%, and more preferably at 100 mol%.

The carboxylic acid component may contain another carboxylic acid component different from the aliphatic dicarboxylic acid. Examples of the other carboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid; and polyvalent carboxylic acids having a valence of 3 or more. These may use 1 type(s) or 2 or more types.

The equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxyl group of the alcohol component (COOH group/OH group) is preferably 0.7 or more, more preferably 0.8 or more, and preferably 1.3 or less, It is preferably 1.2 or less.
The polyester resin can be produced by a method similar to the method exemplified for the amorphous polyester resin described later.

(Crystalline composite resin)
The polyester resin segment of the crystalline composite resin is made of, for example, the above-mentioned crystalline polyester resin.
The addition polymerized resin segment of the crystalline composite resin is made of, for example, an addition polymerized product of a raw material monomer containing a styrene compound.

The addition polymerization resin segment is, for example, an addition polymerization product of a raw material monomer containing a styrene compound.
Examples of the styrene compound include unsubstituted or substituted styrene. Examples of the substituent substituted with styrene include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfonic acid group or a salt thereof.
Examples of the styrene compound include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid and salts thereof. Of these, styrene is preferable.
Further, the addition-polymerized resin segment preferably contains a structural unit derived from styrene as a main structural unit. Here, "containing as a main constituent unit" means that the content of styrene in the raw material monomer forming the addition polymerization resin segment (raw material monomer of the addition polymerization resin segment) is 50% by mass or more, The content of styrene in the raw material monomer forming the addition-polymerized resin segment is more preferably 65% by mass or more, further preferably 75% by mass or more, and may be 100% by mass, further preferably 100% by mass. %.

Examples of raw material monomers other than styrene compounds include (meth)acrylic acid esters such as alkyl (meth)acrylate, benzyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate; ethylene, propylene, butadiene, and the like. Olefins; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; N-vinyl compounds such as N-vinylpyrrolidone. .. Among these, (meth)acrylic acid ester is preferable, and alkyl (meth)acrylate is more preferable.
The number of carbon atoms of the alkyl group in the alkyl (meth)acrylate is preferably 1 or more, more preferably 6 or more, still more preferably 10 or more, and preferably 24 or less, more preferably 22 or less, still more preferably 20. It is below.
Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, (iso)propyl (meth)acrylate, (iso or tertiary)butyl (meth)acrylate, and (meth ) (Iso)amyl acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, (meth)acrylic acid ( Iso)dodecyl, (meth)acrylic acid (iso)palmityl, (meth)acrylic acid (iso)stearyl, (meth)acrylic acid (iso)behenyl, and the like, and (meth)acrylic acid 2-ethylhexyl or (meth) Stearyl acrylate is preferred, and stearyl (meth)acrylate is more preferred.

When a (meth)acrylic acid ester is used as a raw material monomer of the addition polymerization resin segment, the content of the (meth)acrylic acid ester in the raw material monomer is preferably 5% by mass or more, and more preferably 10% by mass. % Or more, more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 35% by mass or less, further preferably 25% by mass or less.

The crystalline composite resin preferably has a constitutional unit derived from both the reactive monomers, which is bonded to the polyester resin segment and the addition-polymerized resin segment via a covalent bond.
The “structural unit derived from a bireactive monomer” means a unit in which a functional group and an addition polymerizable group of the bireactive monomer have reacted.
Examples of the addition-polymerizable group include a carbon-carbon unsaturated bond.
Examples of the bireactive monomer include addition-polymerizable monomers having at least one functional group selected from a hydroxyl group, a carboxy group, an epoxy group, a primary amino group and a secondary amino group in the molecule. .. Among these, from the viewpoint of reactivity, an addition polymerizable monomer having at least one functional group selected from a hydroxyl group and a carboxy group is preferable, and an addition polymerizable monomer having a carboxy group is more preferable.
Examples of the addition-polymerizable monomer having a carboxy group include acrylic acid, methacrylic acid, fumaric acid, and maleic acid. Among these, acrylic acid and methacrylic acid are preferable, and acrylic acid is more preferable, from the viewpoint of reactivity of both polycondensation reaction and addition polymerization reaction.
The amount of the constitutional unit derived from the bireactive monomer is preferably 1 part by mole or more, more preferably 3 parts by mole or more, and further preferably 5 parts by mole with respect to 100 parts by mole of the alcohol component of the polyester resin segment of the crystalline composite resin. And more preferably 30 parts by mole or less, more preferably 20 parts by mole or less, and further preferably 10 parts by mole or less.

The content of the polyester resin segment in the crystalline composite resin is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 65% by mass or more, even more preferably 70% by mass or more, even more preferably 75 mass% or more, and preferably 97 mass% or less, more preferably 95 mass% or less, even more preferably 92 mass%, even more preferably 88 mass% or less, even more preferably 85 mass% or less. ..

The content of the addition-polymerized resin segment in the crystalline composite resin is preferably 3% by mass or more, more preferably 5% by mass or more, further preferably 8% by mass or more, even more preferably 12% by mass or more, still more preferably Is 15% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, further preferably 35% by mass or less, still more preferably 30% by mass or less, still more preferably 25% by mass or less. Is.

The amount of the constitutional unit derived from the bireactive monomer in the crystalline composite resin is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 0.8% by mass or more, and , Preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less.

The mass ratio of the crystalline polyester segment to the addition-polymerized resin segment in the crystalline composite resin (crystalline polyester segment/addition-polymerized resin segment) is preferably 40/60 or more, more preferably 50/60 from the viewpoint of low-temperature fixability. 50 or more, more preferably 60/40 or more, even more preferably 65/35 or more, even more preferably 70/30 or more, still more preferably 75/25 or more, and preferably 95/5 or less, more It is preferably 92/8 or less, more preferably 88/12 or less, still more preferably 85/15 or less.

The total amount of the constituent units derived from the polyester resin segment, the addition-polymerized resin segment, and the bireactive monomer in the crystalline composite resin is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. And 100% by mass or less, and more preferably 100% by mass.

The above amount is calculated based on the ratio of the amounts of the raw material monomer of the polyester resin segment, the raw material monomer of the addition-polymerized resin segment, the bireactive monomer, and the polymerization initiator, and the dehydration amount due to polycondensation in the polyester resin segment etc. is excluded. When a polymerization initiator is used, the mass of the polymerization initiator is included in the addition polymerization resin segment for calculation.

The crystalline composite resin may be produced, for example, by a method including a step A of polycondensing an alcohol component and a carboxylic acid component and a step B of addition-polymerizing a raw material monomer of an addition-polymerized resin segment and a bireactive monomer. ..
Step B may be performed after step A, step A may be performed after step B, or step A and step B may be performed at the same time.
In step A, a part of the carboxylic acid component is subjected to a polycondensation reaction, then step B is carried out, and then the rest of the carboxylic acid component is added to the polymerization system, and the polycondensation reaction of step A and, if necessary, both reactions are carried out. A method of further promoting the reaction with the polymerizable monomer is preferable.

The conditions of step A can be the same as the method exemplified for the amorphous polyester resin described later.

Examples of the radical polymerization initiator for the addition polymerization in step B include peroxides such as dicumyl peroxide and dibutyl peroxide, persulfates such as sodium persulfate, and 2,2′-azobis(2,4-dimethyl). And azo compounds such as valeronitrile).
The amount of the radical polymerization initiator used is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the raw material monomer of the addition polymerization resin segment.
The temperature of the addition polymerization is preferably 110°C or higher, more preferably 130°C or higher, and preferably 230°C or lower, more preferably 220°C or lower, further preferably 210°C or lower.

(Physical properties of crystalline polyester resin)
The softening point of the crystalline polyester resin (resin C) is preferably 60° C. or higher, more preferably 70° C. or higher, still more preferably 75° C. or higher, and preferably 150° C. or lower, from the viewpoint of low temperature fixability. , More preferably 120° C. or lower, still more preferably 100° C. or lower.

The melting point of the resin C is preferably 40° C. or higher, more preferably 50° C. or higher, even more preferably 60° C. or higher, and preferably 100° C. or lower, more preferably 90° C. or lower, from the viewpoint of low-temperature fixability. More preferably, it is 80° C. or lower.

The softening point and the melting point of the resin C can be appropriately adjusted by the kind and the amount of the raw material monomer, and the production conditions such as the reaction temperature, the reaction time, and the cooling rate. It is determined by the method described.
When two or more resins C are used in combination, it is preferable that the softening point and the melting point values obtained as a mixture thereof are within the above-mentioned ranges.

The content of the resin C in the resin component of the toner is preferably 1% by mass or more, more preferably 2% by mass or more, further preferably 3% by mass or more, still more preferably 4% by mass or more, and preferably Is 50 mass% or less, more preferably 40 mass% or less, still more preferably 35 mass% or less, still more preferably 30 mass% or less.

<<Amorphous polyester resin>>
In the present invention, the binder resin preferably contains an amorphous polyester-based resin (hereinafter, also referred to as “resin A”) in addition to the above-mentioned crystalline polyester-based resin.
Examples of the amorphous polyester resin include an amorphous polyester resin and a modified amorphous polyester resin. Examples of the modified amorphous polyester-based resin include an amorphous urethane-modified polyester-based resin in which a polyester resin is modified with a urethane bond, and an amorphous-epoxy-modified polyester-based resin in which a polyester resin is modified with an epoxy bond. An amorphous composite resin containing a resin, a polyester resin segment and a vinyl resin segment can be mentioned.
Among these, the amorphous polyester resin is preferable.

The amorphous polyester resin is, for example, a condensate of an alcohol component and a carboxylic acid component.
Examples of the alcohol component include alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, alkylene oxide adducts of aromatic diols are preferable.
The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably of the formula (I):

(In the formula, OR ¹ and R ² O are oxyalkylene groups, R ¹ and R ² are each independently an ethylene or propylene group, and x and y are the average number of moles of alkylene oxide added, and each is a positive number. Alkylene oxide of bisphenol A represented by the formula (1) is a number and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 4 or less. It is an adjunct.
Examples of the alkylene oxide adduct of bisphenol A include a propylene oxide adduct of bisphenol A (hereinafter also referred to as “BPA-PO”) and an ethylene oxide adduct of bisphenol A (hereinafter also referred to as “BPA-EO”). You may use these 1 type(s) or 2 or more types.

Among these, the alcohol component is preferably BPA-PO, more preferably BPA-PO and BPA-EO.
In the alcohol component, the number of moles of BPA-PO to the total number of moles of BPA-PO and BPA-EO (BPA-PO/(BPA-PO+BPA-EO)) is preferably 0.1 or more, more preferably 0. It is 2 or more, more preferably 0.3 or more, and preferably 1 or less, more preferably 0.8 or less, still more preferably 0.6 or less.
The content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol% or more, more preferably 90 mol% or more, further preferably 95 mol% or more, and 100 mol% or less, More preferably, it is 100 mol%.

Examples of the linear or branched aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol. , 2,3-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1 , 12-dodecanediol.
Examples of the alicyclic diol include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and hydrogenated bisphenol A alkylene oxide having 2 to 4 carbon atoms (average added mole number of 2 to 12). The following) include adducts.
Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.
These alcohol components may use 1 type(s) or 2 or more types.

Examples of the carboxylic acid component include dicarboxylic acids and trivalent or higher polyvalent carboxylic acids.
Examples of dicarboxylic acids include aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and linear or branched aliphatic dicarboxylic acids is preferable.
Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferable, and terephthalic acid is more preferable.
The amount of the aromatic dicarboxylic acid in the carboxylic acid component is preferably 20 mol% or more, more preferably 30 mol% or more, further preferably 40 mol% or more, and may be 100 mol%, preferably Is 90 mol% or less, more preferably 80 mol% or less, and further preferably 75 mol% or less.

The carbon number of the linear or branched aliphatic dicarboxylic acid is preferably 2 or more, more preferably 3 or more, and preferably 30 or less, more preferably 20 or less.
Examples of the linear or branched aliphatic dicarboxylic acid include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, azelaic acid. , Succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid. Among these, succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms is preferable, and dodecenyl succinic acid is more preferable.
The amount of the linear or branched aliphatic dicarboxylic acid in the carboxylic acid component is preferably 1 mol% or more, more preferably 3 mol% or more, still more preferably 5 mol% or more, and preferably 30 mol%. It is preferably 20 mol% or less, more preferably 10 mol% or less.

The trivalent or higher polyvalent carboxylic acid is preferably a trivalent carboxylic acid, and examples thereof include trimellitic acid and its anhydride.
When a polyvalent carboxylic acid having a valence of 3 or more is contained, the amount of the polyvalent carboxylic acid having a valence of 3 or more is preferably 3 mol% or more, more preferably 10 mol% or more, still more preferably 20 mol% in the carboxylic acid component. It is above, and preferably 50 mol% or less, more preferably 40 mol% or less, and further preferably 30 mol% or less.
These carboxylic acid components may be used alone or in combination of two or more.

The ratio [COOH group/OH group] of the carboxylic group of the carboxylic acid component to the hydroxyl group of the alcohol component is preferably 0.7 or more, more preferably 0.8 or more, and preferably 1.3 or less, more preferably Is 1.2 or less.

(Method for producing resin A)
The resin A is obtained, for example, by polycondensation of an alcohol component and a carboxylic acid component.
If necessary, an esterification catalyst such as di(2-ethylhexanoic acid)tin (II), dibutyltin oxide, or titanium diisopropylate bistriethanolaminate may be added to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. 0.01 parts by mass or more and 5 parts by mass or less; an esterification cocatalyst such as gallic acid (the same as 3,4,5-trihydroxybenzoic acid) is 0 based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Polycondensation may be performed using 0.0001 parts by mass or more and 0.5 parts by mass or less.
The temperature of the polycondensation reaction is preferably 120° C. or higher, more preferably 160° C. or higher, even more preferably 180° C. or higher, and preferably 250° C. or lower, more preferably 230° C. or lower. The polycondensation may be performed in an inert gas atmosphere.

(Physical properties of resin A)
The softening point of the resin A is preferably 70° C. or higher, more preferably 90° C. or higher, even more preferably 100° C. or higher, and preferably 150° C. or lower, more preferably 145° C. or lower, further preferably 140° C. or lower. Is.
The glass transition temperature of the resin A is preferably 30°C or higher, more preferably 40°C or higher, further preferably 50°C or higher, and preferably 80°C or lower, more preferably 75°C or lower, further preferably 70°C. It is below.

The acid value of the resin A is preferably 1 mgKOH/g or more, more preferably 2 mgKOH/g or more, further preferably 3 mgKOH/g or more, and preferably 40 mgKOH/g or less, more preferably 30 mgKOH/g or less, further It is preferably 20 mgKOH/g or less.
The softening point, the glass transition temperature, and the acid value of the resin A can be appropriately adjusted according to the types of raw material monomers and the amount thereof, and the production conditions such as reaction temperature, reaction time, and cooling rate, and their values. Is determined by the method described in the examples.
When two or more resins A are used in combination, the softening point, glass transition temperature, and acid value obtained as a mixture thereof are preferably within the above-mentioned ranges.

The content of the resin A in the resin component of the toner is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 65% by mass or more, and preferably 99% by mass or less, more preferably 98% by mass or less. The content is less than or equal to mass%, more preferably less than or equal to 97% by mass, and even more preferably less than or equal to 96% by mass.

[Colorant]
In the present invention, the colorant is carbon black having a DBP (dibutyl phthalate) oil absorption of 25 mL/100 g or more and 45 mL/100 g or less.
By using a specific amount of carbon black having a specific DBP oil absorption amount as a colorant together with an amorphous resin, the electrostatic charge having high coloring power, excellent low-temperature fixability, and excellent hot offset resistance is obtained. An image developing toner is obtained.
The DBP oil absorption of carbon black is preferably 30 mL/100 g or more, more preferably from the viewpoint of obtaining a toner for electrostatic image development that has a higher tinting strength, excellent low-temperature fixability, and excellent hot offset resistance. Is 35 mL/100 g or more, more preferably 37 mL/100 g or more, and preferably 44 mL/100 g or less, more preferably 43 mL/100 g or less, further preferably 40 mL/100 g or less.
The DBP oil absorption of carbon black is measured in accordance with ISO 4656 (JIS K6217-4:2008) "How to obtain oil absorption".

Examples of carbon black include furnace black, thermal lamp black, acetylene black, and channel black. Of these, furnace black is preferable from the viewpoint of coloring power and charge control.

The pH value of carbon black is preferably 6.0 or more, more preferably 6.4 or more, further preferably 6.7 or more, and preferably 9.2 or less, from the viewpoint of further improving the image density. It is more preferably 9.0 or less, still more preferably 8.6 or less, still more preferably 8.2 or less.
Specifically, the pH value of carbon black can be measured by the following procedure.
(1) Collect 5 g of carbon black and 50 mL of distilled water of pH 7 in a container and mix them.
(2) This is boiled for 15 minutes and then cooled to room temperature in 30 minutes.
(3) A pH meter electrode is immersed in this supernatant liquid to measure the pH.
Examples of the pH meter include "HM30R" (manufactured by Toa DKK Co., Ltd.).

The BET specific surface area of carbon black is preferably 50 m ² /g or more, more preferably 60 m ² /g or more, still more preferably 65 m ² /g or more, still more preferably 67 m ² from the viewpoint of coloring power and offset resistance. /G or more, and preferably 130 m ² /g or less, more preferably 120 m ² /g or less, still more preferably 100 m ² /g or less, still more preferably 90 m ² /g or less.
The BET specific surface area of carbon black is measured according to JIS K 6217-2:2017.

Examples of commercially available carbon blacks include “Regal T30R”, “Regal T40R” (above, manufactured by Cabot Japan Co., Ltd.), and “Nipex 35” (manufactured by Orion Engineered Carbons Co., Ltd.).

The content of the colorant is 8 parts by mass or more, preferably 9 parts by mass or more, and more preferably 9.5 parts by mass or more with respect to 100 parts by mass of the binder resin, from the viewpoint of obtaining high coloring power, and From the viewpoint of low-temperature fixability and hot offset resistance, the amount is 20 parts by mass or less, preferably 18 parts by mass or less, more preferably 15 parts by mass or less, and further preferably 12 parts by mass or less.

In the present invention, in addition to the above-described carbon black having a specific DBP oil absorption amount, as a colorant, other colorants may be contained within a range that does not impair the effects of the present invention. The content of the colorant is preferably 30% by mass or less, more preferably 10% by mass or less, further preferably 5% by mass or less, still more preferably 3% by mass or less, and still more preferably another coloring agent. It is not to contain.

〔Release agent〕
Examples of the release agent include wax.
Examples of the wax include hydrocarbon wax, ester wax, silicone wax, and fatty acid amide wax.
Examples of the hydrocarbon wax include mineral or petroleum hydrocarbon wax such as paraffin wax and Fischer-Tropsch wax; and synthetic hydrocarbon wax such as polyolefin wax such as polyethylene wax, polypropylene wax and polybutene wax.
Examples of the ester wax include mineral or petroleum ester wax such as montan wax; plant ester wax such as carnauba wax, rice wax and candelilla wax; and animal ester wax such as beeswax.
Examples of the fatty acid amide wax include oleic acid amide and stearic acid amide. These may use 1 type(s) or 2 or more types.
Among these, at least one of the hydrocarbon wax and the ester wax is preferable, and it is more preferable to use the hydrocarbon wax and the ester wax together.

The melting point of the release agent is preferably 60° C. or higher, more preferably 70° C. or higher, and preferably 160° C. or lower, more preferably 140° C. or lower, further preferably 120° C. or lower, even more preferably 100° C. It is below.
Further, in the present invention, from the viewpoint of obtaining a toner for developing an electrostatic charge image having excellent offset resistance, it is preferable to include paraffin wax having a melting point of 100° C. or less as a release agent. The inclusion of paraffin wax having a melting point of 100° C. or less is preferable because a sufficient releasing effect can be obtained even when the amount of carbon black added is large. In the present invention, by using carbon black having a DBP oil absorption in a specific range, adsorption to carbon black when the releasing agent is melted is suppressed, and even when paraffin wax having a relatively low melting point is used, As a result of suppressing adsorption to carbon black, a particularly excellent releasing effect can be obtained by using the paraffin wax having the above-mentioned melting point.
The melting point of the paraffin wax is preferably 95° C. or lower, more preferably 90° C. or lower, further preferably 85° C. or lower, even more preferably 80° C. or lower.
The melting point of the release agent is measured by the method described in Examples.
The content of the paraffin wax having a melting point of 100° C. or lower is preferably 10% by mass or more, more preferably 20% by mass, based on the total amount of the release agent, from the viewpoint of obtaining a toner for developing an electrostatic image having excellent offset resistance. As described above, it is more preferably 40% by mass or more, and may be 100% by mass.

The content of the release agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, further preferably 3 parts by mass or more, and still more preferably 5 parts by mass with respect to 100 parts by mass of the resin component in the toner. The amount is not less than 20 parts by mass, preferably not more than 20 parts by mass, more preferably not more than 15 parts by mass, further preferably not more than 8 parts by mass.

(Charge control agent)
In the present invention, in step 1, it is preferable to melt-knead the charge control agent together with the binder resin, the release agent, and the colorant described above.
The charge control agent may be either a positively chargeable charge control agent or a negatively chargeable charge control agent.
Examples of the positively chargeable charge control agent include nigrosine dyes such as “Nigrosine base EX”, “Oil black BS”, “Oil black SO”, “Bontron N-01”, “Bontron N-04”, and “Bontron N-07”. , "Bontron N-09", "Bontron N-11" (above, manufactured by Orient Chemical Industry Co., Ltd.), etc.; triphenylmethane dye containing a tertiary amine as a side chain; quaternary ammonium salt compound, for example " Bontron P-51" (manufactured by Orient Chemical Industry Co., Ltd.), cetyltrimethylammonium bromide, "COPY CHARGE PX VP435" (manufactured by Clariant Co., Ltd.) and the like; polyamine resins such as "AFP-B" (manufactured by Orient Chemical Co., Ltd.) and the like. Imidazole derivatives such as "PLZ-2001", "PLZ-8001" (above, manufactured by Shikoku Chemicals Co., Ltd.) and the like; styrene-acrylic resins such as "FCA-701PT" (manufactured by Fujikura Kasei Co., Ltd.) and the like. Be done.

Examples of the negatively chargeable charge control agent include metal-containing azo dyes such as "Varifast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", and "Bontron S-36" ( As described above, manufactured by Orient Chemical Industry Co., Ltd., “Aizenspiron Black TRH”, “T-77” (manufactured by Hodogaya Chemical Industry Co., Ltd.), etc.; metal compounds of benzylic acid compounds, for example, “LR-147”, “ LR-297" (above, manufactured by Nippon Carlit Co., Ltd.); metal compounds of salicylic acid compounds, for example, "Bontron E-81", "Bontron E-84", "Bontron E-88", "Bontron E-304". (Above, manufactured by Orient Chemical Co., Ltd.), “TN-105” (manufactured by Hodogaya Chemical Co., Ltd.), etc.; copper phthalocyanine dye; quaternary ammonium salt, for example, “COPY CHARGE NX VP434” (manufactured by Clariant Co., Ltd.); Nitroimidazole derivatives and the like; organometallic compounds and the like.
Among the charge control agents, negatively chargeable charge control agents are preferable, and metal-containing azo dyes are more preferable.

The content of the charge control agent is preferably 0.01 parts by mass or more, more preferably 0.2 parts by mass or more, still more preferably 0.5 parts by mass or more with respect to 100 parts by mass of the resin component in the toner. And preferably 10 parts by mass or less, more preferably 5 parts by mass or less, still more preferably 3 parts by mass or less, still more preferably 2 parts by mass or less.

The mixture of step 1 further contains additives such as magnetic powder, fluidity improver, conductivity adjuster, reinforcing filler such as fibrous substance, antioxidant, anti-aging agent and cleaning improver. Good.

The melt kneading in step 1 can be performed using a known kneader such as a closed kneader, a single-screw extruder, a twin-screw extruder, or an open roll kneader. Among these, the open roll type kneader is preferable because the kneading heat generated during the melt kneading can be easily released.
Here, the open roll type kneader means that the melt-kneading section is not closed and is open, and has a plurality of raw material supply ports and kneaded material discharge ports provided along the axial direction of the roll. It is preferably provided, and from the viewpoint of production efficiency, a continuous open roll kneader is preferable.
The continuous open roll kneader is preferably a kneader having at least two rolls, and two rolls having different peripheral speeds, that is, a high rotation side roll having a high peripheral speed and a low peripheral speed having a low peripheral speed are used. It is preferable that the kneader has two rolls including a rotation side roll. In the present invention, from the viewpoint of improving the dispersibility of the colorant in the binder resin, and from the viewpoint of reducing the mechanical force during melt kneading and suppressing heat generation, the high rotation side roll is a heating roll, the low rotation side roll. Is preferably a chill roll.
The temperature of the roll can be adjusted by, for example, the temperature of the heat medium passed through the inside of the roll, and each roll may be divided into two or more and the heat medium of different temperature may be passed through.

From the viewpoint of reducing the mechanical force during melt kneading, suppressing heat generation, and improving the durability of the toner, the temperature of the raw material charging side end of the high rotation side roll is preferably 80° C. or higher, more preferably 100. C. or higher, more preferably 120.degree. C. or higher, and preferably 200.degree. C. or lower, more preferably 180.degree. C. or lower, still more preferably 160.degree. C. or lower. Further, from the same viewpoint, the temperature of the raw material feeding side end of the low rotation side roll is preferably 10° C. or higher, more preferably 20° C. or higher, further preferably 30° C. or higher, and preferably 100° C. or lower, The temperature is more preferably 70°C or lower, and further preferably 50°C or lower.

The difference in the set temperature between the raw material input side end and the kneaded product discharge side end of the high rotation side roll is from the viewpoint of preventing desorption of the kneaded product from the roll, and reduces the mechanical force during melt kneading to suppress heat generation. From this viewpoint, it is preferably 20°C or higher, more preferably 30°C or higher, and preferably 60°C or lower, more preferably 50°C or lower. The difference between the set temperature of the raw material charging side end of the low rotation side roll and the kneaded material discharge side end is to improve the dispersibility of the colorant into the binder resin, and to reduce the mechanical force during melt kneading, From the viewpoint of suppressing heat generation, it is preferably 0°C or higher, and preferably 50°C or lower, more preferably 30°C or lower, and further preferably 10°C or lower.

The peripheral speed of the high rotation side roll is preferably 2 m/min or more, from the viewpoint of improving the dispersibility of the colorant in the binder resin, and reducing the mechanical force during melt kneading and suppressing heat generation. It is preferably 10 m/min or more, more preferably 25 m/min or more, and preferably 100 m/min or less, more preferably 75 m/min or less, still more preferably 50 m/min or less. From the same viewpoint, the peripheral speed of the roll on the low rotation side is preferably 1 m/min or more, more preferably 5 m/min or more, further preferably 15 m/min or more, and preferably 90 m/min or less. Is 60 m/min or less, more preferably 30 m/min or less. The ratio of the peripheral speeds of the two rolls (low rotation side roll/high rotation side roll) is preferably 1/10 or more, more preferably 3/10 or more, and preferably 9/10 or less, It is more preferably 8/10 or less.

The structure, size, material, etc. of each roll are not particularly limited. The surface of the roll has grooves used for kneading, and examples of the shape include a linear shape, a spiral shape, a wavy shape, and an uneven shape.

After the melt-kneading, it is preferable that the kneaded product is appropriately cooled until it reaches a hardness capable of being pulverized, and then subjected to the subsequent step 2 to carry out a pulverizing step and classification/classification to obtain toner particles. Here, cooling means cooling the kneaded product to 0° C. or more and 50° C. or less, or cooling to the glass transition temperature or less of the binder resin in the kneaded product.

<Step 2>
The pulverization in step 2 may be performed in multiple stages. For example, the melt-kneaded product may be roughly pulverized to 1 mm or more and 5 mm or less and then finely pulverized to a desired particle size.
Examples of a crusher suitably used for coarse crushing include a hammer mill, an atomizer, and a rotoplex. Examples of a crusher preferably used for fine crushing include a fluidized bed type jet mill, a collision plate type jet mill, and a rotary mechanical mill. From the viewpoint of pulverization efficiency, it is preferable to use a fluidized bed type jet mill and a collision plate type jet mill, and it is more preferable to use a collision plate type jet mill.

The pulverization (coarse pulverization or fine pulverization) may be performed in the presence of silica particles, preferably hydrophobic silica particles, from the viewpoint of improving the fluidity of the toner and suppressing the occurrence of filming. Among these, it is preferable to carry out fine pulverization in the presence of silica particles.
The hydrophobic silica is silica having at least its surface subjected to a hydrophobic treatment. The method of hydrophobizing treatment is not particularly limited, and examples of the hydrophobizing agent include silane coupling agents such as hexamethyldisilazane (HMDS) and dimethyldichlorosilane (DMDS), silicones such as dimethyl silicone oil and amino-modified silicone oil. Examples include oil treatment agents. Among these, the silane coupling agent is preferable, and the treatment amount with the hydrophobic treatment agent is preferably 1 to 7 mg/m ² per surface area of the silica particles.
When finely pulverizing in the presence of silica particles, the coarsely pulverized product and silica particles are preferably mixed in advance using a Henschel mixer or the like. The number average particle diameter of the silica particles used is preferably 6 nm or more, more preferably 8 nm or more, still more preferably 12 nm or more, and preferably from the viewpoint of improving the fluidity of the toner and suppressing the occurrence of filming. Is 25 nm or less, more preferably 20 nm or less, still more preferably 16 nm or less.
When pulverizing in the presence of silica particles, the amount of silica to be added is 100 parts by mass of the melt-kneaded product or the coarsely pulverized product thereof from the viewpoint of improving the fluidity of the toner and suppressing the occurrence of filming. It is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, still more preferably 1.0 parts by mass or more, still more preferably 1.5 parts by mass or more, and preferably 10 parts by mass. Parts or less, more preferably 8 parts by mass or less, still more preferably 5 parts by mass or less, still more preferably 3 parts by mass or less.

Examples of the classifier used for classification include a rotor type classifier, an airflow type classifier, an inertia type classifier, and a sieve type classifier. In the classification step, the pulverized product removed due to insufficient pulverization may be subjected to the pulverization step again, or the pulverization step and the classification step may be repeated if necessary.
Through the above steps, toner particles are obtained.

[Toner particles]
The volume median particle diameter D ₅₀ of the toner particles is preferably 2 μm or more, more preferably 4 μm or more, further preferably 6 μm or more, and preferably 12 μm or less, more preferably from the viewpoint of obtaining a high quality image. It is 10 μm or less, more preferably 8 μm or less.
From the viewpoint of obtaining a high quality image, the CV value of the toner particles is preferably 12% or more, more preferably 14% or more, further preferably 16% or more, still more preferably 20% or more, and preferably It is 45% or less, more preferably 40% or less, still more preferably 35% or less, still more preferably 30% or less.
The method for measuring the volume median particle diameter D ₅₀ and the CV value of the toner particles is according to the method described in Examples.

[External additive]
The toner is preferably added to the surface of the toner particles using a fluidizing agent or the like as an external additive.
Examples of the external additive include particles of inorganic materials such as silicon oxide such as hydrophobic silica, titanium oxide, alumina, cerium oxide and carbon black, and polymer particles such as polycarbonate, polymethylmethacrylate and silicone resin. Among these, silicon oxide particles are preferable, and hydrophobic silica particles are more preferable.
The external additive may be used alone or in combination of two or more kinds, or even when hydrophobic silica is used, for example, two or more kinds of silica having different properties such as number average particle diameter may be used in combination. Good.
The number average particle diameter of the external additive is preferably 5 nm or more, more preferably 10 nm or more, and preferably 100 nm or less, more preferably 80 nm or less.
The number average particle diameter of the external additive is measured by the method described in Examples.

When an external additive is used, the addition amount of the external additive is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 5 parts by mass or less, relative to 100 parts by mass of the toner particles. It is more preferably 4 parts by mass or less.
The method of externally adding the external additive to the toner is not particularly limited, but a method of mixing the external additive and the toner particles with a mixer such as a Henschel mixer to attach the external additive to the toner surface (external addition) is available. preferable.

The toner is used for electrostatic image development in electrophotographic printing. The toner can be used, for example, as a one-component developer or as a two-component developer by mixing with a carrier.

In the following examples and the like, measurement and evaluation of each physical property were performed by the following methods.
[Measuring method]
[DBP oil absorption]
The DBP oil absorption of carbon black was measured in accordance with ISO 4656 (JIS K6217-4:2008) "Method of determining oil absorption". The DBP oil absorption is the value of carbon black before being dispersed.

[PH value]
The pH value of carbon black was measured by the method of JIS K5101-17-2 after preparing an aqueous suspension of 10% by mass of carbon black or a sludge.

[BET specific surface area]
The BET specific surface area of carbon black was measured in accordance with "How to obtain specific surface area" of JIS K6217-2:2001. The BET specific surface area is the value of carbon black before being dispersed.

[Acid value]
The acid value of the resin and wax was measured according to the neutralization titration method described in JIS K0070:1992. However, the measurement solvent was chloroform.

[Softening point of resin, crystallinity index, melting point and glass transition temperature]
(1) Using a softening point flow tester “CFT-500D” (manufactured by Shimadzu Corp.), a load of 1.96 MPa was applied by a plunger while heating 1 g of a sample at a heating rate of 6° C./min, and the diameter was increased. It was extruded from a nozzle having a length of 1 mm and a length of 1 mm. The amount of plunger drop of the flow tester was plotted against the temperature, and the temperature at which half the sample flowed out was taken as the softening point.
(2) Crystallinity index Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of a sample is weighed in an aluminum pan, and the temperature is lowered to 0° C./min. Cooled to °C. Then, the sample was held as it was for 1 minute, and then heated to 180° C. at a heating rate of 10° C./min to measure the amount of heat. Of the observed endothermic peaks, the temperature of the peak having the largest peak area is defined as the maximum endothermic peak temperature (1), and (softening point (°C))/(maximum endothermic peak temperature (1) (°C)) The crystallinity index was determined.
(3) Melting point and glass transition temperature Using a differential scanning calorimeter “Q100” (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of a sample is weighed in an aluminum pan and heated to 200° C. Then, the temperature was lowered to 0° C. at a temperature decreasing rate of 10° C./min. Then, the sample was heated at a heating rate of 10° C./min and the amount of heat was measured. Of the observed endothermic peaks, the temperature of the peak having the largest peak area was defined as the maximum endothermic peak temperature (2). In the case of crystalline resin, the peak temperature was taken as the melting point.
In the case of an amorphous resin, when a peak is observed, the temperature of the peak is measured. When a peak is not observed and a step is observed, the tangent line showing the maximum inclination of the curve of the step and the step The temperature at the intersection with the extension of the low temperature side baseline was defined as the glass transition temperature.

[Melting point of wax]
A differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.) was used to weigh 0.02 g of the sample into an aluminum pan and raise the temperature to 200°C. Cooled to 0°C at °C/min. Next, the sample was heated at a heating rate of 10° C./min, the amount of heat was measured, and the maximum peak temperature of endotherm was taken as the melting point.

[Number average particle diameter of silica]
The particle size (average value of major axis and minor axis) of 500 particles was measured from a scanning electron microscope (SEM) photograph, and the average value was defined as the number average particle diameter.

[Volume median particle diameter D ₅₀ , CV value]
The volume median particle diameter D ₅₀ of the toner particles was measured as follows.
・Measuring machine: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.)
・Aperture diameter: 50 μm
-Analysis software: "Multisizer (registered trademark) III version 3.51" (manufactured by Beckman Coulter, Inc.)
Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.)
Dispersion: Polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" [manufactured by Kao Corporation, HLB (Hydrophile-Lipophile Balance) = 13.6] is dissolved in the electrolytic solution to obtain a dispersion having a concentration of 5% by mass. Got
-Dispersion condition: 10 mg of the measurement sample was added to 5 mL of the dispersion liquid, dispersed for 1 minute with an ultrasonic disperser, then 25 mL of the electrolytic solution was added, and further dispersed for 1 minute with the ultrasonic disperser, A sample dispersion was prepared.
-Measurement conditions: The sample dispersion was added to 100 mL of the electrolytic solution to adjust the particle size of 30,000 particles to a concentration at which measurement was possible in 20 seconds, then 30,000 particles were measured, and the particle size was measured. The volume median particle diameter D ₅₀ and the volume average particle diameter were determined from the distribution.
The CV value (%) was calculated according to the following formula.
CV value (%)=(standard deviation of particle size distribution/volume average particle size)×100

[Coloring power: image density of printed matter]
A commercially available printer "Microline (registered trademark) 5400" (manufactured by Oki Data Co., Ltd.) was used for the high-quality paper "J paper A4 size" (manufactured by Fuji Xerox Co., Ltd.), and the toner adhesion amount on the paper was 0.35±0. A solid image composed of 0.02 mg/cm ² was output.
Next, prepare the same printer with the fixing device modified to a variable temperature, set the temperature of the fixing device to the minimum fixing temperature +20° C., fix the toner in the A4 vertical direction at a speed of 2.5 seconds per sheet, and print the printed matter. Obtained.
30 sheets of high-quality paper "J paper A4 size" are laid under the printed matter, and the reflection image density of the solid image portion of the printed matter output is measured by a colorimeter "SpectroEye" (manufactured by GretagMacbeth Co., Ltd., irradiation condition; standard light source D50, observation). The field of view was 2°, the density standard was DINNB, and the absolute white standard was used), and the values measured at arbitrary 10 points on the image were averaged to obtain the image density. The larger the value, the better the coloring power.

[Evaluation of low temperature fixability]
An image is output to high-quality paper "J paper A4 size" (manufactured by Fuji Xerox Co., Ltd.) using a commercially available printer "Microline (registered trademark) 5400" (manufactured by Oki Data Co., Ltd.), and the amount of toner adhered on the paper is 0. A solid image of 0.35±0.02 mg/cm ² was output as an unfixed image with a length of 50 mm, leaving a blank portion of 5 mm from the upper end of the A4 paper. The fixing device mounted on the printer was modified to have a variable temperature, the temperature of the fixing device was set to 110° C., and the toner was fixed at a speed of 2.5 seconds per sheet in the A4 vertical direction to obtain a printed matter. At 110° C., it was confirmed that all toners were in a cold offset or unmelted state.
In the same manner, the temperature of the fixing device was increased by 5° C., the toner was fixed, and a printed matter was obtained.
A 50 mm long piece of mending tape "Scotch (registered trademark) Mending Tape 810" (manufactured by Sumitomo 3M Limited, width 18 mm) was lightly applied from the blank area at the top edge of the printed matter to the solid image. After that, a weight of 500 g was placed and pressed back and forth once at a speed of 10 mm/s. Then, the attached tape was peeled off from the lower end side at a peeling angle of 180° and a speed of 10 mm/s to obtain a printed matter after peeling the tape. 30 sheets of high-quality paper "J paper A4 size" are laid under the printed matter before and after the tape is attached, and the reflection image density of the fixed image portion of each printed matter before and after the tape is attached is measured by the colorimeter "SpectroEye" ( GretMacbeth, light conditions; standard light source D50, observation visual field 2°, density standard DINNB, absolute white standard) were used for measurement, and the fixing ratio was calculated from each reflection image density according to the following formula.
Fixing rate (%)=(reflection image density after tape peeling/reflection image density before tape attachment)×100
The lowest temperature at which the fixing rate is 90% or more was defined as the lowest fixing temperature. The lower the minimum fixing temperature is, the better the low temperature fixing property is.

[Evaluation of hot offset resistance]
An unfixed image was output by the same method as the evaluation of the low temperature fixability described above. The fixing test was conducted at a fixing temperature between 150° C. and 180° C. in increments of 5° C., and the presence or absence of hot offset was determined by the following method, and the test was carried out up to the temperature at which hot offset occurred.
Note that cold offset refers to a phenomenon in which toner adheres to the fixing roller when the fixing temperature is low and the toner on the unfixed image does not melt sufficiently or the releasability is not good. Here, the phenomenon that the toner adheres to the fixing roller because the viscoelasticity of the toner on the unfixed image decreases when the fixing temperature is raised or the releasability becomes poor at high temperature. The occurrence of cold offset or hot offset can be judged again by whether or not the toner adheres to the paper when the fixing roller makes one round. In this test, whether the toner adheres to the area 87 mm from the top of the solid image is detected. It was judged whether or not.
Here, the hot offset generation temperature is a temperature at which hot offset starts to occur. The temperature lower than the hot offset generation temperature by 5° C. was defined as the maximum temperature at which hot offset did not occur.
In the evaluation of the hot offset generation temperature, the difference in the evaluation temperature of 5° C. is clearly recognized in the fixing property of the toner.

[Production of resin]
Production Example A1: Production of Amorphous Polyester Resin A-1 A raw material monomer for a polyester resin other than trimellitic anhydride shown in Table 1 and an esterification catalyst were equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple. The mixture was placed in a 20 L four-necked flask, and the temperature was raised to 200° C. under a nitrogen atmosphere to react for 6 hours. After further raising the temperature to 210° C., trimellitic anhydride was added, and the mixture was reacted at normal pressure (101.3 kPa) for 1 hour, and further reacted at 40 kPa until the desired softening point was reached, and then the amorphous polyester resin A-1 was obtained. Table 1 shows the physical properties of the obtained resin.

Production Example A2: Production of Amorphous Polyester Resin A-2 A raw material monomer of the polyester resin shown in Table 1 and an esterification catalyst were used in a 20-liter volume equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple. The mixture was placed in a two-necked flask, heated to 235° C. under a nitrogen atmosphere and reacted until the reaction rate reached 80%, and then reacted at 8 kPa until a desired softening point was reached. Resin A-2 was obtained. Table 1 shows the physical properties of the obtained resin. In addition, the reaction rate means a value of the amount of generated reaction water/theoretical amount of generated water×100.

Production Example C1
Production of Crystalline Polyester Resin C-1 The raw material monomers and esterification catalyst for the polyester resin shown in Table 2 were placed in a 20-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple. In a nitrogen atmosphere, the temperature is increased to 130° C., then the temperature is increased from 130° C. to 200° C. over 10 hours, the pressure is reduced to 8 kPa while maintaining the temperature at 200° C., and the reaction is performed for 1 hour. C-1 was obtained. Table 2 shows the physical properties of the obtained resin.

Production Example C2
Production of Crystalline Polyester Resin C-2 The raw material monomers and esterification catalyst of the polyester resin shown in Table 2 were placed in a 20-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple. The mixture was heated to 160° C. in a nitrogen atmosphere and reacted for 6 hours. Then, the mixed liquid of the raw material monomer of the styrene resin shown in Table 2, the bireactive monomer, and the polymerization initiator was dripped over 1 hour. After carrying out the addition polymerization reaction for 1 hour while maintaining the temperature at 160° C., the pressure was reduced to 8.3 kPa and the temperature was maintained for 1 hour. Further, the temperature was raised to 200° C. over 8 hours, and the reaction was performed at 8.3 kPa for 2 hours to obtain a crystalline polyester resin C-2. Table 2 shows the physical properties of the obtained resin.

Production Examples C3 and C4: Production of Crystalline Polyester Resins C-3 and C-4 A crystalline polyester resin was produced in the same manner as in Production Example C2 except that the amounts of the raw material monomers used were changed as shown in Table 2. C-3 and C-4 were obtained. Table 2 shows the physical properties of the obtained resin.

Examples 1 to 7, and Comparative Example 1 and Comparative Example 2
Manufacture of Toners 1 to 9 Table 3 shows various characteristics of carbon black which is a coloring agent used in Examples and Comparative Examples.
Binder resin (total 100 parts by mass) and carbon black (10 parts by mass) shown in Table 4, 1.0 part by mass of negatively chargeable charge control agent "T-77" (manufactured by Hodogaya Chemical Industry Co., Ltd.), and mold release Agent "Carnauba wax No. 1" (manufactured by Kato Hiroyuki, Carnauba wax, melting point 85°C) 3.0 parts by mass and "HNP-9" (Nippon Seiwa Co., Ltd., paraffin wax, melting point 78°C) 3 After stirring and mixing 0.0 part by mass with a Henschel mixer for 2 minutes, the mixture was melt-kneaded under the following conditions.
A continuous two-roll open-roll type kneader "Kneedex" (manufactured by Nippon Coke Industry Co., Ltd., roll outer diameter: 14 cm, effective roll length: 80 cm) was used. The operating conditions of the continuous two-roll open-roll type kneader are as follows: high rotation side roll (front roll) rotation speed 75 r/min (peripheral speed 32.97 m/min), low rotation side roll (back roll) rotation speed 50 r/min. (Circumferential speed 21.98 m/min), Roll gap at the end of the kneaded material supply port side was 0.1 mm. Regarding the heating medium temperature and the cooling medium temperature in the roll, the temperature of the raw material charging side end of the high rotation side roll is 145° C. and the temperature of the kneaded product discharging side end is 110° C. The temperature of the end was 35°C, and the temperature of the end on the kneaded product discharge side was 35°C. The feed rate of the raw material mixture was 10 kg/h, and the average residence time was about 6 minutes.

The obtained melt-kneaded product was cooled to 20° C. or lower while being rolled with a cooling roll, and the cooled melt-kneaded product was roughly pulverized to about 3 mm by a Rotoplex (manufactured by Toa Machine Industry Co., Ltd.). Then, to 100 parts by mass of the obtained coarsely pulverized product, 2.0 parts by mass of hydrophobic silica “R972” (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: DMDS, number average particle diameter: 16 nm) was used with a Henschel mixer. Mix for 2 minutes.
Using an IDS crushing/classifying machine (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), which is an airflow type jet mill, the obtained mixture is adjusted to have a volume median particle diameter (D ₅₀ ) of 7.0±0.2 μm. Was crushed and classified.
100 parts by mass of the obtained particles, 2.5 parts by mass of hydrophobic silica “RY50” (manufactured by Nippon Aerosil Co., Ltd., number average particle size: 0.04 μm), and hydrophobic silica “Cabosil (registered trademark) TS720” (Cabot) 1.0 part by mass of Japan Co., Ltd. (number average particle diameter: 0.012 μm) was put in a Henschel mixer, stirred, and passed through a 150-mesh sieve to obtain toner 1 to toner 9. Table 4 shows the evaluation results of the obtained toner.

As described above, the results of Examples and Comparative Examples show that according to the manufacturing method of the present invention, it is possible to provide a black toner excellent in low-temperature fixability and hot offset resistance while maintaining high coloring power.
From the comparison between the example and the comparative example 1, it can be seen that by using carbon black having a DBP oil absorption amount within a predetermined range, excellent hot offset resistance can be obtained while maintaining low temperature fixability. Further, from the comparison between Example and Comparative Example 2, the above results show that the toner containing the crystalline polyester resin does not retain the low temperature fixability for the first time by using the carbon black having the DBP oil absorption amount within the predetermined range. It can be seen that high coloring power can be obtained.

Claims (7)

A method for producing an electrostatic charge image developing toner, comprising a step of melt-kneading at least a binder resin, a release agent, and a colorant,
The binder resin contains a crystalline polyester resin,
The colorant is carbon black having a DBP oil absorption of 25 mL/100 g or more and 45 mL/100 g or less,
The content of the colorant is 8 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin,
Method for producing toner for developing electrostatic image. The crystalline polyester resin is an alcohol component containing an α,ω-aliphatic diol having 9 to 14 carbon atoms and a carboxylic acid containing an α,ω-aliphatic dicarboxylic acid compound having 9 to 14 carbon atoms. The method for producing a toner for developing an electrostatic charge image according to claim 1, which is a crystalline polyester resin obtained by polycondensing a component or a crystalline composite resin having a crystalline polyester segment derived from the crystalline polyester resin. .. The method for producing an electrostatic charge image developing toner according to claim 1, wherein the crystalline polyester resin is a crystalline composite resin containing a crystalline polyester segment and an addition polymerization resin segment. The mass ratio of the crystalline polyester segment to the addition polymerization resin segment in the crystalline composite resin (crystalline polyester segment/addition polymerization resin segment) is 40/60 or more and 95/5 or less. A method for producing a toner for developing a charge image. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the content of the crystalline polyester resin in the binder resin is 1% by mass or more and 50% by mass or less. The method for producing an electrostatic charge image developing toner according to claim 1, wherein the release agent contains paraffin wax having a melting point of 100° C. or lower. The method for producing an electrostatic charge image developing toner according to claim 1, wherein the melt kneading is performed using an open roll type kneader.