JP2022048034A - Toner and toner manufacturing method - Google Patents

Abstract

To provide a toner which is excellent in low temperature fixability, charging stability and storage property.SOLUTION: A toner has toner particles including a core-shell structure that a surface of a toner core is covered with a shell layer, in which the toner core contains a crystalline resin A and an amorphous resin B, the crystalline resin A has a carboxy group, an acid value of the crystalline resin A is 10.0 mgKOH/g or more and 50.0 mgKOH/g or less, a hydroxyl value of the crystalline resin A is 20.0 mgKOH/g or less, the shell layer contains a thermosetting resin C having a functional group that can react with the carboxy group, an interface between the toner core and the shell layer has a resin component formed by crosslinking reaction of the carboxy group of the crystalline resin A and a functional group of a thermosetting resin C having a functional group that can react with the carboxy group of the crystalline resin A, and a thickness of the shell layer is 3 nm or more and 200 nm or less.SELECTED DRAWING: None

Description

The present invention relates to toner used in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and a toner jet method, and a method for manufacturing toner.

In recent years, as electrophotographic full-color copiers have become widespread, further energy saving is required. For that purpose, a toner that can be satisfactorily fixed even when the temperature of the fixing roller is low is required. Patent Document 1 proposes various toners containing a crystalline resin having a sharp melt property in order to improve low-temperature fixing performance, but the heat-resistant storage stability and charge stability are lowered due to the crystalline resin. Sometimes.

Patent Document 2 proposes using a core-shell structure to use a crystalline resin and an amorphous resin for the core and a resin having a high glass transition point for the shell. By such a method, heat-resistant storage stability and charge stability can be improved. However, since the thickness of the shell hinders the low temperature fixing property, further improvement is required.

Patent Document 3 proposes a toner in which the surface of the toner core is coated with a thin film containing a thermosetting component. However, if the crystalline resin is even slightly exposed on the surface of the toner, the charge stability is lowered and the concentration stability is lowered. Therefore, further improvement is required.

Japanese Unexamined Patent Publication No. 2011-123352 Japanese Unexamined Patent Publication No. 2018-180188 Japanese Unexamined Patent Publication No. 2013-109330

An object of the present invention is to provide a toner that solves the above problems. Specifically, it is an object of the present invention to provide a toner excellent in low temperature fixing property, heat storage property and charge stability.

The toner according to the present invention is a toner having toner particles having a core-shell structure in which the surface of the toner core is covered with a shell layer.
The toner core contains a crystalline resin A and an amorphous resin B, and contains the crystalline resin A and the amorphous resin B.
The crystalline resin A has a carboxy group and has a carboxy group.
The acid value of the crystalline resin A is 10.0 mgKOH / g or more and 50.0 mgKOH / g or less.
The hydroxyl value of the crystalline resin A is 20.0 mgKOH / g or less, and the hydroxyl value is 20.0 mgKOH / g or less.
The shell layer contains a thermosetting resin C having a functional group capable of reacting with the carboxy group.
The interface between the toner core and the shell layer is
With the carboxy group of the crystalline resin A,
The crystalline resin A has a resin component formed by a cross-linking reaction with the functional group of the thermosetting resin C having a functional group capable of reacting with the carboxy group.
The shell layer is characterized in that the thickness is 3 nm or more and 200 nm or less.

The method for producing toner according to the present invention is as follows.
A method for producing toner having toner particles having a core-shell structure in which the surface of the toner core is covered with a shell layer.
A step of reacting a crystalline resin A contained in the toner core with a shell material in an aqueous medium to form the shell layer covering the surface of the toner core to obtain toner particles is included.
The shell material has a thermosetting resin C having an oxazoline group.
The toner core contains the crystalline resin A and the amorphous resin B, and the toner core contains the crystalline resin A and the amorphous resin B.
The crystalline resin A contains a carboxy group and has
The acid value of the crystalline resin A is 10.0 mgKOH / g or more and 50.0 mgKOH / g or less.
The hydroxyl value of the crystalline resin A is 20.0 mgKOH / g or less, and the hydroxyl value is 20.0 mgKOH / g or less.
The shell layer contains a resin component containing a unit having an oxazoline group and a unit having an amide bond.
The amide bond is characterized by being formed by reacting the oxazoline group of the thermosetting resin C contained in the shell material with the carboxy group of the crystalline resin A contained in the toner core. ..

According to the present invention, it is possible to provide a toner having excellent low temperature fixing property, heat storage property and charge stability.

The toner according to the present invention is
A toner having toner particles having a core-shell structure in which the surface of the toner core is covered with a shell layer.
The toner core contains a crystalline resin A and an amorphous resin B, and contains the crystalline resin A and the amorphous resin B.
The crystalline resin A has a carboxy group and has a carboxy group.
The acid value of the crystalline resin A is 10.0 mgKOH / g or more and 50.0 mgKOH / g or less.
The hydroxyl value of the crystalline resin A is 20.0 mgKOH / g or less, and the hydroxyl value is 20.0 mgKOH / g or less.
The shell layer contains a thermosetting resin C having a functional group capable of reacting with the carboxy group.
The interface between the toner core and the shell layer is
With the carboxy group of the crystalline resin A,
The crystalline resin A has a resin component formed by a cross-linking reaction with the functional group of the thermosetting resin C having a functional group capable of reacting with the carboxy group.
The shell layer is characterized in that the thickness is 3 nm or more and 200 nm or less.

The present inventors consider the action and effect of using the toner of the present invention having such a structure as follows.
When the acid value of the crystalline resin A used in the present invention has a specific range, the carboxy group of the crystalline resin A is functional at the interface between the core and the shell layer of the thermosetting resin C used for the shell layer. It has a resin component formed by a cross-linking reaction with a group. Due to this resin component, the shell layer has a structure that selectively covers the crystalline resin A. Therefore, even if an ultra-thin shell layer is formed, the crystalline resin A is less likely to be exposed, and it is possible to achieve both low-temperature fixability, charge stability, and heat-resistant storage stability.

Here, the resin component refers to a polymer formed by a cross-linking reaction between a polymer constituting the crystalline resin A and a polymer constituting a thermosetting resin.

The acid value of the crystalline resin A is 10.0 mgKOH / g or more and 50.0 mgKOH / g or less, and more preferably 25.0 mgKOH / g or more and 40.0 mgKOH / g or less. When the acid value of the crystalline resin A is smaller than 10 mgKOH / g, the reaction with the functional group of the thermosetting resin C in the shell layer becomes insufficient, the crystalline resin A is exposed, and the heat-resistant storage stability and charge stability are improved. It gets worse. If the acid value of the crystalline resin is too large, the amount of residual carboxy groups after reacting with the functional groups of the thermosetting resin in the shell layer increases, and the charge stability deteriorates. When the hydroxyl value of the crystalline resin A is 20.0 mgKOH / g or less, the amount of water adsorbed can be reduced and the charge stability can be maintained even in a harsh environment such as a high temperature and high humidity environment.

When the thickness of the shell layer is 3 nm or more and 200 nm or less, the low temperature fixability, heat-resistant storage stability, and charge stability of the toner can be ensured. More preferably, it is 3 nm or more and 20 nm or less. If the thickness of the shell layer is too thin, the heat-resistant storage stability and charge stability of the toner will be insufficient. If the shell layer is too thick, the low temperature fixability of the toner will be insufficient.

The acid value of the amorphous resin B is preferably 20.0 mgKOH / g or less. As a result, the functional group of the thermosetting resin C used for the shell layer and the carboxy group of the crystalline resin A can selectively react with each other, and the charge stability and the heat-resistant storage stability are improved. The hydroxyl value of the amorphous resin B is preferably 40.0 mgKOH / g or less. This suppresses the adsorption of water and improves the charge stability.

The functional group capable of cross-linking with the carboxy group of the crystalline resin is preferably an unopened oxazoline group. In this case, the resin component has a structural unit derived from an oxazoline group formed by the cross-linking reaction with the carboxy group. The unopened oxazoline group easily reacts with the carboxy group, can form a strong amide bond with the crystalline resin of the toner core while keeping the shell layer thin, and has good low-temperature fixability, charge stability, and heat-resistant storage stability. To become. As an example of the method for confirming this amide bond, there is a method of measuring toner particles by infrared spectroscopy and confirming whether or not there is a peak of 1630 cm ^-1 . As a method for showing that a large amount is present at the core-shell interface, the peak intensity of 1630 cm ^-1 obtained by using Ge as an ATR crystal is Pa (Ge), and the peak intensity of 1720 cm ^-1 derived from the ester group of the polyester resin is set. When (C = O peak of polyester) is Pb (Ge), the peak intensity of 1630 cm ^-1 obtained by using diamond as an ATR crystal is Pa (Dy), and the peak intensity of 1720 cm ^-1 is Pb (Dy). In addition, Pa (Dy) / Pb (Dy) is smaller than Pa (Ge) / Pb (Ge).

From the viewpoint of charge stability and low-temperature fixability, the amorphous resin B is preferably a polyester resin.

Hereinafter, the composition of the toner of the present invention will be described in detail.
[Crystalline resin A]
The crystalline resin A used in the toner of the present invention has a carboxy group, an acid value of 10.0 mgKOH / g or more and 50.0 mgKOH / g or less, and a hydroxyl value of 20 mgKOH / g or less. The crystalline resin is a resin in which an endothermic peak is observed in differential scanning calorimetry (DSC).

The crystalline resin A is not particularly limited, but is mainly made of a polyester resin from the viewpoint of ensuring low-temperature fixability and having a suitable acid value that leads to ensuring the above-mentioned heat-resistant storage stability and charge stability. It is preferable to use it as an ingredient.

The crystalline polyester is preferably obtained by polycondensing a monomer composition containing an aliphatic diol having 2 to 22 carbon atoms and an aliphatic dicarboxylic acid having 2 to 22 carbon atoms as main components.

The aliphatic diol having 2 to 22 carbon atoms (more preferably 6 to 12 carbon atoms) is not particularly limited, but is preferably a chain-like (more preferably linear) aliphatic diol.

For example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,4-butadiene glycol, trimethylene glycol, tetramethylene glycol. , Pentamethylene glycol, hexamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol, neopentyl glycol and the like.

Among these, ethylene glycol, diethylene glycol, 1,4-butanediol, and linear aliphatics such as 1,6-hexanediol, α, ω-diol are preferably exemplified.

Of the above alcohol components, preferably 50% by mass or more, more preferably 70% by mass or more is an alcohol selected from an aliphatic diol having 2 to 22 carbon atoms.

Polyhydric alcohol monomers other than the above aliphatic diols can also be used. Examples of the dihydric alcohol monomer among the polyhydric alcohol monomers include aromatic alcohols such as polyoxyethylene glycol A and polyoxypropylene glycol A; 1,4-cyclohexanedimethanol and the like. Among the polyhydric alcohol monomers, the trihydric or higher polyhydric alcohol monomer includes aromatic alcohols such as 1,3,5-trihydroxymethylbenzene; pentaerythritol, dipentaerythritol, and tripentaerythritol. , 1,2,4-Butantriol, 1,2,5-Pentantriol, Glycerin, 2-Methylpropantriol, 2-Methyl-1,2,4-Butantriol, Trimethylolethane, Trimethylolpropane and other fats Triol alcohol and the like can be mentioned.

Further, monovalent alcohol may be used to the extent that the characteristics of the crystalline polyester are not impaired. Examples of the monohydric alcohol include monoalcohols such as n-butanol, isobutanol, sec-butanol, n-hexanol, n-octanol, 2-ethylhexanol, cyclohexanol, and benzyl alcohol, capryl alcohol (decanol), and undecanol. , Lauryl alcohol (dodecanol), tridecanol, myristyl alcohol (tetradecanol), pentadecanol, palmityl alcohol (hexadecanol), margalyl alcohol (heptadecanol), stearyl alcohol (octadecanol), nonadecanol, araki Jill alcohol (Icosanol) and the like can be mentioned.

On the other hand, the aliphatic dicarboxylic acid having 2 to 22 carbon atoms (more preferably 6 to 12 carbon atoms) is not particularly limited, but is preferably a chain (more preferably linear) aliphatic dicarboxylic acid. ..

Specific examples include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, glutaconic acid, azelaic acid, sebacic acid, nonandicarboxylic acid, decandicarboxylic acid, undecandicarboxylic acid, and dodecandicarboxylic acid. Examples thereof include maleic acid, fumaric acid, mesaconic acid, citraconic acid and itaconic acid, and those obtained by hydrolyzing these acid anhydrides or lower alkyl esters are also included.

Of the above carboxylic acid components, preferably 50% by mass or more, more preferably 70% by mass or more is a carboxylic acid selected from an aliphatic dicarboxylic acid having 2 to 22 carbon atoms.

A polyvalent carboxylic acid other than the above-mentioned aliphatic dicarboxylic acid having 2 to 22 carbon atoms can also be used. Among other polyvalent carboxylic acid monomers, the divalent carboxylic acid includes aromatic carboxylic acids such as isophthalic acid and terephthalic acid; aliphatic carboxylic acids of n-dodecyl succinic acid and n-dodecenyl succinic acid; cyclohexanedicarboxylic acid. Examples thereof include alicyclic carboxylic acids such as acids, and these acid anhydrides or lower alkyl esters are also included.

Among other carboxylic acid monomers, the trivalent or higher polyvalent carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimeritic acid), 2,5,7-naphthalenetricarboxylic acid, and 1,2. Aromatic carboxylic acids such as 2,4-naphthalenetricarboxylic acid and pyromellitic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2-methyl-2 -Examples include aliphatic carboxylic acids such as methylenecarboxypropane and the like, and derivatives such as acid anhydrides or lower alkyl esters thereof are also included.

Further, it may contain a monovalent carboxylic acid to the extent that the characteristics of the crystalline polyester are not impaired. Examples of the monovalent carboxylic acid include benzoic acid, naphthalenecarboxylic acid, salicylic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, phenoxyacetic acid, biphenylcarboxylic acid, acetic acid, propionic acid, butyric acid, octanoic acid and capric acid ( Decanoic acid), undesic acid, lauric acid (dodecanoic acid), tridecyl acid, myristyl acid (tetradecanoic acid), pentadecyl acid, palmitic acid (hexadecanoic acid), margaric acid (heptadecanoic acid), stearic acid (octadecanoic acid), nonadecic acid , Arakidic acid (icosanoic acid).

The content of the crystalline resin A is preferably 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the amorphous resin B from the viewpoint of low temperature fixability and chargeability in a high temperature and high humidity environment.

The crystalline polyester can be produced according to a conventional polyester synthesis method. For example, after the above-mentioned carboxylic acid monomer and alcohol monomer are subjected to an esterification reaction or a transesterification reaction, a crystalline polyester is obtained by subjecting it to a polycondensation reaction under reduced pressure or by introducing nitrogen gas according to a conventional method. Obtainable. Then, by further adding the above-mentioned aliphatic compound and performing an esterification reaction, a desired crystalline polyester can be obtained.

The esterification or transesterification reaction can be carried out using a usual esterification catalyst or transesterification catalyst such as sulfuric acid, titanium butoxide, dibutyltin oxide, manganese acetate and magnesium acetate, if necessary.

Further, the polycondensation reaction can be carried out using a usual polymerization catalyst, for example, a known catalyst such as titanium butoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, germanium dioxide and the like. .. The polymerization temperature and the amount of catalyst are not particularly limited and may be appropriately determined.

In the esterification or transesterification reaction or polycondensation reaction, a method of collectively charging all the monomers may be used in order to increase the strength of the obtained crystalline polyester. Further, in order to reduce the number of low molecular weight components, a method such as first reacting a divalent monomer and then adding a trivalent or higher valent monomer to react may be used.
The peak molecular weight of the crystalline resin A is preferably 1000 or more and 6000 or less from the viewpoint of low-temperature fixability and heat-resistant storage.
The weight average molecular weight Mw of the crystalline resin A is preferably 4000 or more and 30,000 or less from the viewpoint of low temperature fixability and heat storage stability.

[Amorphous resin B]
The amorphous resin B used for the toner of the present invention is not particularly limited, and the following polymers or resins can be used.

For example, homopolymers of styrene such as polystyrene, poly-p-chlorstyrene, polyvinyltoluene and its substitution products; styrene-p-chlorstyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalin copolymer. , Styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chlormethylmethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinylmethyl ether copolymer, styrene-vinyl Stylized polymer such as ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-inden copolymer; polyvinyl chloride, phenol resin, natural resin modified phenol resin, natural resin modified maleic acid resin , Acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, kumaron-inden resin, petroleum resin, etc. can be used. ..

Among these, from the viewpoint of low temperature fixability, it is preferable to use polyester resin as a main component. The main component indicates that the content is 50% by mass or more.

Monomers used in the polyester resin include polyvalent alcohol (divalent or trivalent or higher alcohol), polyvalent carboxylic acid (divalent or trivalent or higher carboxylic acid), acid anhydride thereof or lower alkyl ester thereof. Is used.

Here, from the viewpoint of improving heat storage stability and chargeability, it is effective to partially crosslink the amorphous resin B in the molecule when producing a branched polymer, and for that purpose, a polyfunctional compound having a trivalent or higher valence is effective. It is preferable to use. Therefore, it is preferable that the raw material monomer of the polyester resin contains a carboxylic acid having a valence of trivalent or higher, an acid anhydride thereof or a lower alkyl ester thereof, and / or an alcohol having a valence of trivalent or higher.

The following monomers can be used as the polyhydric alcohol monomer used in the polyester resin.

（式中、Ｒはエチレン又はプロピレン基であり、ｘ及びｙはそれぞれ０以上の整数であり、かつ、ｘ＋ｙの平均値は０以上１０以下である。）

（式（Ｂ）中、Ｒ’は－ＣＨ_２ＣＨ_２－、－ＣＨ_２－ＣＨ（ＣＨ_３）－又は－ＣＨ_２－Ｃ（ＣＨ_３）_２－を示し、ｘ’、ｙ’は０以上の整数であり、且つ、ｘ＋ｙの平均値は０～１０である。） The divalent alcohol component includes ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1, 6-Hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydride bisphenol A, bisphenol represented by the formula (A) and derivatives thereof; diols represented by the formula (B); Can be mentioned.

(In the formula, R is an ethylene or propylene group, x and y are integers of 0 or more, respectively, and the average value of x + y is 0 or more and 10 or less.)

(In the formula (B), R'indicates -CH ₂ CH _2- , -CH ₂ -CH (CH ₃ )-or -CH ₂ -C (CH ₃ ) _2- , and x', y'is 0 or more. It is an integer of, and the average value of x + y is 0 to 10.)

Examples of the trihydric or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol. , 1,2,5-pentantriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene Can be mentioned. Of these, glycerol, trimethylolpropane, and pentaerythritol are preferably used. These divalent alcohols and trihydric or higher alcohols can be used alone or in combination of two or more.

The following monomers can be used as the polyvalent carboxylic acid monomer used in the polyester resin.

Examples of the divalent carboxylic acid component include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebatic acid, azelaic acid, and malonic acid. n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n-octenyl succinic acid, n-octyl succinic acid, isooctenyl succinic acid, isooctyl succinic acid, anhydrides of these acids and Examples thereof include these lower alkyl esters.
Of these, maleic acid, fumaric acid, terephthalic acid, and n-dodecenyl succinic acid are preferably used.

Examples of the trivalent or higher carboxylic acid, its acid anhydride or its lower alkyl ester include 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalentricarboxylic acid and 1,2,4-naphthalenetricarboxylic acid. , 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra ( Methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empole trimeric acid, acid anhydrides thereof or lower alkyl esters thereof.

Of these, 1,2,4-benzenetricarboxylic acid, that is, trimellitic acid or a derivative thereof is preferably used because it is inexpensive and reaction control is easy. These divalent carboxylic acids and the like and trivalent or higher carboxylic acids can be used alone or in combination of two or more.

The method for producing the polyester resin is not particularly limited, and a known method can be used. For example, the above-mentioned alcohol monomer and carboxylic acid monomer are simultaneously charged and polymerized through an esterification reaction, a transesterification reaction, and a condensation reaction to produce a polyester resin. The polymerization temperature is not particularly limited, but is preferably in the range of 180 ° C. or higher and 290 ° C. or lower.

In the polymerization of polyester, for example, a polyester resin polymerized using a tin catalyst which can use a polymerization catalyst such as a titanium catalyst, a tin catalyst, zinc acetate, antimony trioxide, and germanium dioxide is more preferable.

The peak molecular weight of the amorphous resin B is preferably 4000 or more and 13000 or less from the viewpoint of low temperature fixability and hot offset resistance. Further, the acid value of the amorphous resin B is 20 mgKOH / g or less from the viewpoint of suppressing the reaction with the functional group of the thermosetting resin C of the shell layer and from the viewpoint of charge stability in a high temperature and high humidity environment. It is preferable from. Further, it is preferable that the hydroxyl value of the amorphous resin B is 40 mgKOH / g or less from the viewpoint of charge stability in a high temperature and high humidity environment.

Further, the amorphous resin may be used by mixing a low molecular weight amorphous resin B and a high molecular weight amorphous resin B'. The content ratio (B / B') of the low molecular weight amorphous resin B and the high molecular weight amorphous resin B'is 60/40 or more and 90/10 or less on a mass basis for low temperature fixability and resistance. It is preferable from the viewpoint of hot offset property.
The peak molecular weight of the low molecular weight amorphous resin B is preferably 3000 or more and 8000 or less from the viewpoint of low temperature fixability.
The peak molecular weight of the high molecular weight amorphous resin B'is more than 8000 and preferably 30,000 or less from the viewpoint of hot offset resistance.
The weight average molecular weight Mw of the low molecular weight amorphous resin B is preferably 4000 or more and 10000 or less from the viewpoint of low temperature fixability.
It is preferable that the weight average molecular weight Mw of the high molecular weight amorphous resin B'is larger than 10,000 and not more than 100,000 from the viewpoint of hot offset resistance.

[Thermosetting resin C]
The thermosetting resin C is a resin having a site capable of cross-linking with the carboxy group of the crystalline resin A. The site capable of the cross-linking reaction is preferably an oxazoline group. The thermosetting resin C can be obtained, for example, by copolymerizing an oxazoline having a double bond such as 2-vinyl-2-oxazoline with a compound having a double bond such as methyl methacrylate. The constituent monomers of the thermosetting resin C are not particularly limited. The thermosetting resin C may be a polymer containing only a monomer containing a unit having a site capable of a cross-linking reaction. Alternatively, it may be a copolymer containing a compound other than the compound such as methyl methacrylate in addition to the monomer containing a unit having a site capable of a cross-linking reaction.
It is preferable that the weight average molecular weight Mw of the thermosetting resin C is larger than 30,000 and not more than 150,000 from the viewpoint of dispersibility.

[Resin component in which crystalline resin A and thermosetting resin C are crosslinked]
An endothermic peak is observed in the differential scanning calorimetry (DSC) of the resin component in which the crystalline resin A and the thermosetting resin C are crosslinked. When the thermosetting resin C contains an oxazoline group, the resin component in which the crystalline resin A and the thermosetting resin C are crosslinked has an amide bond. The weight average molecular weight Mw of the resin component formed by the cross-linking reaction between the crystalline resin A and the thermosetting resin C is preferably 34,000 or more and 200,000 or less from the viewpoint of low temperature fixability and heat storage stability.

As commercially available oxazoline-based cross-linking agents, Epocross (registered trademark) K2010E, K2020E, K2030E, WS-300, WS-500, WS-700 (all manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.) and the like can also be used.

The thermosetting resin C preferably does not contain a basic substance. In the shell layer forming step described later, since the shell layer does not contain a basic substance, it is possible to prevent suppression of the crosslinking reaction due to the neutralization reaction of the carboxy group of the crystalline resin A contained in the toner core.

[Release agent]
Examples of the release agent that can be used for the toner of the present invention include the following. Hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, alkylene copolymers, microcrystallin wax, paraffin wax, Fishertroph wax; oxides of hydrocarbon waxes such as polyethylene oxide wax or block copolymers thereof. Waxes containing fatty acid esters such as carnauba wax as main components; deoxidized fatty acid esters such as carnauba wax partially or wholly deoxidized.

In addition, the following can be mentioned. Saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brushzic acid, eleostearic acid, and varinaric acid; , Saturated alcohols such as melisyl alcohol; polyhydric alcohols such as sorbitol; fatty acids such as palmitic acid, stearic acid, behenic acid, montanic acid, and stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubil alcohol. , Esters with alcohols such as ceryl alcohol, melisyl alcohol; fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislaurin Saturated fatty acid bisamides such as acid amides, hexamethylene bisstearic acid amides; ethylene bisoleic acid amides, hexamethylene bisoleic acid amides, N, N'diorail adipic acid amides, N, N'diorail sevacinic acid amides. Unsaturated fatty acid amides such as; aromatic bisamides such as m-xylene bisstearate amide, N, N'distearyl isophthalic acid amide; calcium stearate, calcium laurate, zinc stearate, magnesium stearate. Aliper metal salts (generally referred to as metal soap); waxes grafted on aliphatic hydrocarbon wax using vinyl monomers such as styrene and acrylic acid; with fatty acids such as behenic acid monoglyceride Partial esterified product of polyhydric alcohol; a methyl ester compound having a hydroxyl group obtained by hydrogenation of vegetable fats and oils.

The content of the release agent is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin. Here, the binder resin refers to the total of the crystalline resin A and the amorphous resin B.

Further, in the endothermic curve at the time of temperature rise measured by the differential scanning calorimetry (DSC) device, the peak temperature of the maximum endothermic peak of the wax is preferably 60 ° C. or higher and 110 ° C. or lower. It is preferable that the peak temperature of the maximum endothermic peak of the wax is within the above range because both the storage stability of the toner and the hot offset resistance can be achieved.

[Colorant]
Examples of the colorant that can be contained in the toner of the present invention include the following.

Examples of the black colorant include carbon black; those colored black by using a yellow colorant, a magenta colorant, and a cyan colorant. Although the pigment may be used alone as the colorant, it is more preferable to improve the sharpness by using the dye and the pigment in combination from the viewpoint of the image quality of the full-color image.

Examples of the magenta toner pigment include the following. C. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48: 2, 48: 3, 48: 4, 49, 50, 51, 52, 53, 54, 55, 57: 1, 58, 60, 63, 64, 68, 81: 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 146, 147, 150, 163, 184, 202, 206, 207, 209, 238, 269, 282; C.I. I. Pigment Violet 19; C.I. I. Bat Red 1, 2, 10, 13, 15, 23, 29, 35.

Examples of the magenta toner dye include the following. C. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121; C.I. I. Disperse thread 9; C.I. I. Solvent Violet 8, 13, 14, 21, 27; C.I. I. Oil-soluble dyes such as Disper Violet 1, C.I. I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40; C.I. I. Basic dyes such as Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28.

Examples of the cyan toner pigment include the following. C. I. Pigment Blue 2, 3, 15: 2, 15: 3, 15: 4, 16, 17; C.I. I. Bat Blue 6; C.I. I. Acid blue 45, a copper phthalocyanine pigment in which one or more and five or less phthalocyanine methyl groups are substituted in the phthalocyanine skeleton.
As the dye for cyan toner, C.I. I. There is Solvent Blue 70.

Examples of the pigment for yellow toner include the following. C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185; C.I. I. Bat Yellow 1, 3, 20.
Examples of the dye for yellow toner include C.I. I. There is Solvent Yellow 162.

The amount of the colorant used is preferably 0.1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.

[Charge control agent]
The toner of the present invention may also contain a charge control agent, if necessary. As the charge control agent contained in the toner, known ones can be used, but in particular, a metal compound of an aromatic carboxylic acid which is colorless, has a high charge speed of the toner, and can stably maintain a constant charge amount is preferable.

Negative charge control agents include salicylate metal compounds, naphthoic acid metal compounds, dicarboxylic acid metal compounds, polymer compounds having sulfonic acid or carboxylic acid in the side chain, sulfonates or sulfonic acid esterified products in the side chain. Examples thereof include a high molecular weight compound, a high molecular weight compound having a carboxylate or a carboxylic acid esterified product in a side chain, a boron compound, a urea compound, a silicon compound, and a calix array. Examples of the positive charge control agent include a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in the side chain, a guanidine compound, and an imidazole compound. The charge control agent may be added internally or externally to the toner particles. The amount of the charge control agent added is preferably 0.05 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin.

[Inorganic fine particles]
Inorganic fine particles may be contained in the toner, if necessary. The inorganic fine particles may be internally added to the toner particles or may be mixed with the toner particles as an external additive. As the external additive, inorganic fine powders such as silica, titanium oxide and aluminum oxide are preferable. The inorganic fine powder is preferably hydrophobized with a hydrophobizing agent such as a silane compound, silicone oil or a mixture thereof.

As the external additive for improving the fluidity, an inorganic fine powder having a specific surface area of 50 m ² / g or more and 400 m ² / g or less is preferable. Inorganic fine powder having a specific surface area of 10 m ² / g or more and 50 m ² / g or less is preferable for stabilizing durability. Inorganic fine powder having a specific surface area in the above range may be used in combination in order to achieve both improvement in fluidity and stabilization of durability.

The external additive is preferably used in an amount of 0.1 part by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the toner particles. A known mixer such as a Henschel mixer can be used for mixing the toner particles and the external additive.

[Developer]
The toner of the present invention can also be used as a one-component developer, but in order to further improve dot reproducibility, it is possible to mix it with a magnetic carrier and use it as a two-component developer for long-term stable images. Is preferable in that

Examples of the magnetic carrier include iron powder whose surface is oxidized, unoxidized iron powder, and metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, chromium, and rare earth. A magnetic material-dispersed resin carrier (so-called resin carrier) containing a magnetic material such as alloy particles, oxide particles, and ferrite, or a magnetic material and a binder resin that holds the magnetic material in a dispersed state, and the like are generally known. You can use things.

When the toner of the present invention is mixed with a magnetic carrier and used as a two-component developer, the carrier mixing ratio at that time is preferably 2% by mass or more and 15% by mass or less as the toner concentration in the two-component developer. In the case of, good results are obtained. More preferably, it is 4% by mass or more and 13% by mass or less.

[Production method]
The method for producing the toner particles of the present invention is a shell layer forming step formed by reacting the carboxy group of the crystalline resin A contained in the toner core with the crosslinkable site contained in the thermosetting resin C. including. The toner core can be produced by a known method such as a dry method such as a pulverization method, a wet method such as an emulsion aggregation method and a dissolution suspension method.

Hereinafter, an example of the toner manufacturing process by the pulverization method will be described.
In the raw material mixing step, as a material constituting the toner particles, for example, a predetermined amount of other components such as crystalline resin A, amorphous resin B, and if necessary, a mold release agent, a colorant, and a charge control agent. Weigh, mix and mix. Examples of the mixing device include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, a mechano hybrid (manufactured by Nippon Coke Industries, Ltd.) and the like.

Next, the mixed materials are melt-kneaded to disperse the mold release agent and the like in the binder resin. The kneading discharge temperature can be appropriately adjusted depending on the binder resin and colorant used, but is generally preferably 100 to 180 ° C. In the melt-kneading process, a batch-type kneader such as a pressure kneader or a Bambary mixer or a continuous-type kneader can be used, and a single-screw or twin-screw extruder has become the mainstream because of its superiority in continuous production. ing. For example, KTK type twin-screw extruder (manufactured by Kobe Steel), TEM type twin-screw extruder (manufactured by Toshiba Machine Co., Ltd.), PCM kneader (manufactured by Ikekai Iron Works), twin-screw extruder (manufactured by KCC). ), Co-kneader (manufactured by Bus), Kneedex (manufactured by Nippon Coke Industries Co., Ltd.), etc. Further, the resin composition obtained by melt-kneading may be rolled with two rolls or the like and cooled with water or the like in the cooling step.

Then, the cooled product of the resin composition is pulverized to a desired particle size in the pulverization step. In the crushing process, for example, after coarse crushing with a crusher such as a crusher, a hammer mill, or a feather mill, further, for example, a cryptron system (manufactured by Kawasaki Heavy Industries, Ltd.), a super rotor (manufactured by Nisshin Engineering Co., Ltd.), a turbo mill. (Made by Freund Turbo) or a fine crusher using the air jet method.

After that, if necessary, classification of inertial classification type elbow jet (manufactured by Nittetsu Mining Co., Ltd.), centrifugal force classification method turboplex (manufactured by Hosokawa Micron), TSP separator (manufactured by Hosokawa Micron), faculty (manufactured by Hosokawa Micron), etc. Classify using a machine or a sieving machine to obtain a classified product (toner core). Among them, Faculti (manufactured by Hosokawa Micron Co., Ltd.) is preferable in that the toner core can be sphericalized at the same time as the classification, and the transfer efficiency is improved.

Subsequently, the toner core and the shell material (for example, an oxazoline group-containing polymer aqueous solution) are mixed in an aqueous medium to obtain a dispersion liquid. Next, the dispersion liquid is stirred and reacted at a predetermined temperature to form a shell layer. For example, when the shell material is a polymer aqueous solution having an oxazoline group, the formed shell layer has a resin component containing a unit having an oxazoline group and a unit having an amide bond. In the case of the present invention, the amide bond is formed by reacting the oxazoline group of the thermosetting resin C contained in the shell material with the carboxy group of the crystalline resin A contained in the toner core.

The predetermined temperature is preferably 50 ° C. or higher and 70 ° C. or lower. At this time, a carboxylic acid such as acetic acid as a ring-opening agent or a basic substance such as ammonia or sodium hydroxide as a reaction inhibitor may be added. The progress of the crosslinking reaction can be adjusted by adjusting the reaction temperature, reaction time, and additives, and the thickness of the shell layer and the interface state between the core portion and the shell layer can be adjusted. The aqueous medium is a medium containing water as a main component and may contain alcohol or the like miscible with water. After forming the shell layer, the mixture is cooled to room temperature, and the dispersion of toner particles is filtered, washed, and dried using a Büchner funnel to obtain toner particles.

The toner particles may be used as toner as they are, or may be used as toner by adding an external additive to the surface of the toner particles, if necessary. As a method of externalizing the external additive, toner particles and various known external additives are mixed in a predetermined amount, and a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, and a mechano hybrid ( A method of stirring and mixing using a mixing device such as Nippon Coke Industries Co., Ltd.) or Nobilta (Hosokawa Micron Co., Ltd.) as an external mixer can be mentioned.

Next, a method for measuring each physical property according to the present invention will be described.
[Isolation of crystalline resin A, amorphous resin B, thermosetting resin C, resin component obtained by cross-linking crystalline resin A and thermosetting resin C from toner]
Each physical property can be measured using the crystalline resin A, the amorphous resin B, the thermosetting resin C, and the resin component obtained by polymerizing the crystalline resin A and the thermosetting resin C isolated by the following method. can.
First, a toner and a solvent such as THF are mixed and stirred at room temperature or at heating to polymerize the crystalline resin A, the amorphous resin B, the thermosetting resin C, the crystalline resin A and the thermosetting resin C. Dissolve the resin component.
Next, insoluble components contained in the obtained solution, such as an external additive, a mold release agent, a charge control agent, a colorant (pigment, etc.), and the like are removed by centrifugation, filtration, washing, or the like.
Then, for example, by using a GPC equipped with a preparative mechanism, high-speed liquid chromatography (HPLC), or the like, a crystalline resin A, an amorphous resin B, a thermosetting resin C, a crystalline resin A, and a thermosetting resin are used. It is possible to isolate the resin component crosslinked with C.
The method for removing the solvent is preferably carried out by evaporation of the solvent, and the method for evaporating the solvent includes methods such as heating, depressurization, and ventilation.

[Measurement of molecular weight of resin by GPC]
First, the resin is dissolved in o-dichlorobenzene or THF over 24 hours at room temperature. Then, the obtained solution is filtered with a solvent-resistant membrane filter "Maeshori Disc" (manufactured by Tosoh Corporation) having a pore diameter of 0.2 μm to obtain a sample solution. The sample solution is preferably adjusted so that the concentration of the component soluble in THF is about 0.8% by mass. This sample solution is used for measurement under the following conditions.
Equipment: HLC-8121GPC / HT (manufactured by Tosoh Corporation)
Column: TSKgel GMHHR-HHT 7.8 cm I. D x 30 cm 2 stations (manufactured by Tosoh)
Detector: RI for high temperature
Temperature: 135 ° C
Solvent: o-dichlorobenzene (with 0.05% ionol added) or THF
Flow velocity: 1.0 ml / min
Sample: Inject 0.4 ml of 0.1% sample. Measure under the above conditions, and use the molecular weight calibration curve prepared from the monodisperse polystyrene standard sample to calculate the molecular weight of the sample. Further, it is calculated by performing polyethylene conversion by a conversion formula derived from the Mark-Houwink viscosity formula.

[Measuring method of softening point of amorphous resin B]
The softening point of the resin B is measured by using a constant load extrusion type thin tube rheometer "Flow Tester CFT-500D" (manufactured by Shimadzu Corporation) and following the manual attached to the device. In this device, while applying a constant load from the top of the measurement sample with a piston, the temperature of the measurement sample filled in the cylinder is raised and melted, and the melted measurement sample is pushed out from the die at the bottom of the cylinder. A flow curve showing the relationship between and temperature can be obtained.

In the present invention, the softening point is the "melting temperature in the 1/2 method" described in the manual attached to the "flow characteristic evaluation device flow tester CFT-500D". The melting temperature in the 1/2 method is calculated as follows. First, 1/2 of the difference between the piston descent amount Smax at the time when the outflow ends and the piston descent amount Smin at the time when the outflow starts is obtained (this is defined as X. X = (Smax-Smin) /. 2). The temperature of the flow curve when the amount of descent of the piston becomes X in the flow curve is the melting temperature in the 1/2 method.

As a measurement sample, about 1.0 g of resin was compression-molded in an environment of 25 ° C. using a tablet molding compressor (for example, NT-100H, manufactured by NPA System Co., Ltd.) at about 10 MPa for about 60 seconds. Use a columnar one with a diameter of about 8 mm.

The measurement conditions of CFT-500D are as follows.
Test mode: Temperature rise method Start temperature: 50 ° C
Reaching temperature: 200 ° C
Measurement interval: 1.0 ° C
Temperature rise rate: 4.0 ° C / min
Piston cross-sectional area: 1.000 cm ²
Test load (piston load): 10.0 kgf (0.9807 MPa)
Preheating time: 300 seconds Die hole diameter: 1.0 mm
Die length: 1.0 mm

[Measurement of glass transition temperature (Tg) of amorphous resin B]
The glass transition temperature of the resin is measured according to ASTM D3418-82 using a differential scanning calorimeter analyzer "Q2000" (manufactured by TA Instruments).
The melting point of indium and zinc is used for temperature correction of the device detector, and the heat of fusion of indium is used for the correction of calorific value.

Specifically, about 3 mg of resin or toner is precisely weighed, placed in an aluminum pan, and measured under the following conditions using an empty aluminum pan as a reference.
Temperature rise rate: 10 ° C / min
Measurement start temperature: 30 ° C
Measurement end temperature: 180 ° C
Measurement is performed at a heating rate of 10 ° C./min within a measurement range of 30 to 180 ° C. The temperature is once raised to 180 ° C. and held for 10 minutes, then lowered to 30 ° C., and then the temperature is raised again. In this second temperature rise process, a specific heat change is obtained in the temperature range of 30 to 100 ° C. The intersection of the line at the midpoint of the baseline before and after the specific heat change at this time and the differential thermal curve is defined as the glass transition temperature (Tg) of the resin.

[Measurement of melting point of crystalline resin A and mold release agent]
The melting point of indium and zinc is used for temperature correction of the device detector, and the heat of fusion of indium is used for the correction of calorific value. Specifically, about 2 mg of a sample is precisely weighed, placed in an aluminum pan, and an empty aluminum pan is used as a reference, and the temperature rise rate is 10 in the measurement temperature range of 30 to 200 ° C. Measure at ° C / min. In the measurement, the temperature is raised to 200 ° C., then lowered to 30 ° C., and then raised again. The peak temperature of the maximum endothermic peak of the DSC curve in the temperature range of 30 to 200 ° C. in the second temperature raising process is defined as the melting point. There is no holding time after raising the temperature to 200 ° C, and the temperature is lowered to 30 ° C as soon as the temperature reaches 200 ° C.

[Measuring method of weight average particle size (D4) of toner particles]
The weight average particle size (D4) of the toner particles is measured with a precision particle size distribution measuring device "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter) equipped with a 100 μm aperture tube by the pore electric resistance method. Measurement data is measured with 25,000 effective measurement channels using the attached dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter) for setting conditions and analyzing measurement data. Is analyzed and calculated.

As the electrolytic aqueous solution used for the measurement, one in which special grade sodium chloride is dissolved in ion-exchanged water so that the concentration becomes about 1% by mass, for example, "ISOTON II" (manufactured by Beckman Coulter) can be used.

Before performing measurement and analysis, set the dedicated software as follows.
In the "Change standard measurement method (SOM) screen" of the dedicated software, set the total count number of the control mode to 50,000 particles, measure once, and set the Kd value to "Standard particles 10.0 μm" (Beckman Coulter). Set the value obtained using (manufactured by the company). By pressing the threshold / noise level measurement button, the threshold and noise level are automatically set. Also, set the current to 1600 μA, the gain to 2, and the electrolyte to ISOTON II, and check the flash of the aperture tube after measurement.
In the dedicated software "Pulse to particle size conversion setting screen", set the bin spacing to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range to 2 μm or more and 60 μm or less.

The specific measurement method is as follows.
(1) Put about 200 ml of the electrolytic aqueous solution in a 250 ml round bottom beaker made of glass dedicated to Multisizer 3, set it on a sample stand, and stir the stirrer rod counterclockwise at 24 rpm. Then, the dirt and air bubbles in the aperture tube are removed by the "aperture flash" function of the analysis software.

(2) Approximately 30 ml of the electrolytic aqueous solution is placed in a 100 ml flat-bottomed beaker made of glass, and "Contaminone N" (nonionic surfactant, anionic surfactant, organic builder) is used as a dispersant in the electrolytic aqueous solution for precise measurement of pH 7. Add about 0.3 ml of a diluted solution obtained by diluting a 10% by mass aqueous solution of a neutral detergent for cleaning a vessel, manufactured by Wako Pure Chemical Industries, Ltd.) with ion-exchanged water 3 times by mass.

(3) Two oscillators with an oscillation frequency of 50 kHz are built in with the phase shifted by 180 degrees, and are installed in the water tank of the ultrasonic disperser "Ultrasonic Dispension System Tetora 150" (manufactured by Nikkaki Bios) with an electrical output of 120 W. A predetermined amount of ion-exchanged water is added, and about 2 ml of the Contaminone N is added into the water tank.

(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid level of the electrolytic solution in the beaker is maximized.

(5) With the electrolytic aqueous solution in the beaker of (4) being irradiated with ultrasonic waves, about 10 mg of toner is added little by little to the electrolytic aqueous solution and dispersed. Then, the ultrasonic dispersion processing is continued for another 60 seconds. For ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be 10 ° C. or higher and 40 ° C. or lower.

(6) Using a pipette, the aqueous electrolyte solution of (5) in which toner is dispersed is dropped onto the round bottom beaker of (1) installed in the sample stand, and the measured concentration is adjusted to about 5%. .. Then, the measurement is performed until the number of measured particles reaches 50,000.

(7) The measurement data is analyzed by the dedicated software attached to the device, and the weight average particle size (D4) is calculated. The "average diameter" of the analysis / volume statistical value (arithmetic mean) screen when the graph / volume% is set by the dedicated software is the weight average particle diameter (D4).

[Measuring method of average circularity of toner]
The average circularity of the toner is measured by the flow type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) under the measurement and analysis conditions at the time of calibration work.

The measurement principle of the flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) is to capture a flowing particle as a still image and perform image analysis. The sample added to the sample chamber is sent to the flat sheath flow cell by the sample suction syringe. The sample sent into the flat sheath flow is sandwiched between the sheath liquids to form a flat flow. The sample passing through the flat sheath flow cell is irradiated with strobe light at 1/60 second intervals, and it is possible to take a still image of the flowing particles. Moreover, since the flow is flat, the image is taken in a focused state. The particle image is captured by a CCD camera, the captured image is image-processed at an image processing resolution of 512 × 512 pixels (0.37 × 0.37 μm per pixel), the contour of each particle image is extracted, and the particle image is obtained. The projected area S, the peripheral length L, and the like are measured.

Next, the circle-equivalent diameter and the circularity are obtained by using the area S and the perimeter L. The circle equivalent diameter is the diameter of a circle having the same area as the projected area of the particle image, and the circularity C is the value obtained by dividing the circumference length of the circle obtained from the circle equivalent diameter by the circumference length of the particle projection image. It is defined as and calculated by the following formula.
Circularity C = 2 × (π × S) 1/2 / L

When the particle image is circular, the circularity becomes 1.000, and the larger the degree of unevenness on the outer periphery of the particle image, the smaller the circularity. After calculating the circularity of each particle, the range of circularity 0.200 to 1.000 is divided into 800, the arithmetic mean value of the obtained circularity is calculated, and the value is taken as the average circularity.

The specific measurement method is as follows. First, about 20 ml of ion-exchanged water from which impure solids and the like have been removed in advance is placed in a glass container. Among them, as a dispersant, "Contaminone N" (a 10% by mass aqueous solution of a neutral detergent for cleaning a pH 7 precision measuring instrument consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd. ) Is diluted about 3 times by mass with ion-exchanged water, and about 0.2 ml of the diluted solution is added. Further, about 0.02 g of the measurement sample is added, and the dispersion treatment is performed for 2 minutes using an ultrasonic disperser to prepare a dispersion liquid for measurement. At that time, the dispersion liquid is appropriately cooled so that the temperature is 10 ° C. or higher and 40 ° C. or lower. As the ultrasonic disperser, a desktop ultrasonic cleaner disperser (for example, "VS-150" (manufactured by Vervocrea)) having an oscillation frequency of 50 kHz and an electrical output of 150 W is used, and a predetermined amount is contained in the water tank. Ion-exchanged water is added, and about 2 ml of the Contaminone N is added into the water tank.

The flow type particle image analyzer equipped with a standard objective lens (10 times) was used for the measurement, and the particle sheath "PSE-900A" (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion liquid adjusted according to the procedure is introduced into the flow type particle image analyzer, and 3000 toner particles are measured in the HPF measurement mode and the total count mode. Then, by setting the binarization threshold value at the time of particle analysis to 85% and designating the analysis particle diameter, the number ratio (%) of particles in that range and the average circularity can be calculated. The average circularity of the toner was set to a circle equivalent diameter of 1.98 μm or more and 39.96 μm or less, and the average circularity of the toner was determined.

In the measurement, automatic focus adjustment is performed using standard latex particles (for example, "RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A" manufactured by Duke Scientific) is diluted with ion-exchanged water before the start of the measurement. After that, it is preferable to perform focus adjustment every two hours from the start of measurement.

In the embodiment of the present application, a flow-type particle image analyzer that has been calibrated by Sysmex and has received a calibration certificate issued by Sysmex was used. The measurement was performed under the measurement and analysis conditions at the time of receiving the calibration certificate, except that the diameter of the analysis particle was limited to the equivalent circle diameter of 1.98 μm or more and less than 39.69 μm.

[Acid value measurement method]
In the present invention, the acid value is the mass [mg] of potassium hydroxide required to neutralize the acid contained in 1 g of the sample. That is, the mass [mg] of potassium hydroxide required to neutralize free fatty acids and resin acids contained in 1 g of a sample is referred to as an acid value.

In the present invention, the acid value was measured according to JIS K 0070-1992. Specifically, the measurement was performed according to the following procedure.

(1) Preparation of Reagents 1.0 g of phenolphthalein was dissolved in 90 mL of ethyl alcohol (95% by volume), and ion-exchanged water was added to make 100 mL to obtain a phenolphthalein solution.
7 g of special grade potassium hydroxide was dissolved in 5 mL of water, and ethyl alcohol (95% by volume) was added to make 1 L. It was placed in an alkali-resistant container and left for 3 days so as not to come into contact with carbon dioxide. After standing, it was filtered to obtain a potassium hydroxide solution. The obtained potassium hydroxide solution was stored in an alkali-resistant container. As for the factor of the potassium hydroxide solution, take 25 mL of 0.1 mol / L hydrochloric acid in a triangular flask, add a few drops of the phenolphthalein solution, titrate with the potassium hydroxide solution, and neutralize the potassium hydroxide. Obtained from the amount of solution. The above 0.1 mol / L hydrochloric acid used was prepared according to JIS K 8001-1998.

(2) Operation (A) Main test 2.0 g of the sample was placed in a 200 mL Erlenmeyer flask, weighed precisely, 100 mL of a mixed solution of toluene / ethanol (2: 1) was added, and the sample was dissolved over 5 hours. Then, several drops of the above phenolphthalein solution were added as an indicator, and titration was performed using the above potassium hydroxide solution. The end point of the titration is when the light red color of the indicator lasts for 30 seconds.

(B) Blank test The same titration as the above operation was performed except that no sample was added (that is, only a mixed solution of toluene / ethanol (2: 1) was used).

(3) Calculation of acid value The obtained result was substituted into the following formula to calculate the acid value.
AV = [(BA) x f x 5.61] / S
In the above formula, AV indicates the acid value [mgKOH / g], A indicates the addition amount [mL] of the potassium hydroxide solution in the blank test, and B indicates the addition amount [mL] of the potassium hydroxide solution in the main test. Shown, f indicates the factor of the potassium hydroxide solution, and S indicates the mass [g] of the sample.
When the amorphous resin B and the amorphous resin B'are mixed and used in the present invention, the acid value thereof was measured using 1 g of the mixed sample.

[Measurement method of hydroxyl value]
The hydroxyl value is the number of mg of potassium hydroxide required to neutralize acetic acid bonded to the hydroxyl group when acetylating 1 g of the sample. The hydroxyl value of the binder resin is measured according to JIS K 0070-1992, but specifically, it is measured according to the following procedure.

(1) Preparation of Reagents 25 g of special grade acetic anhydride is placed in a 100 ml volumetric flask, pyridine is added to make the total volume 100 ml, and the mixture is sufficiently shaken to obtain an acetylation reagent. The obtained acetylation reagent is stored in a brown bottle so as not to come into contact with moisture, carbon dioxide, or the like.
Dissolve 1.0 g of phenolphthalein in 90 ml of ethyl alcohol (95 vol%) and add ion-exchanged water to make 100 ml to obtain a phenolphthalein solution.
Dissolve 35 g of special grade potassium hydroxide in 20 ml of water and add ethyl alcohol (95 vol%) to make 1 liter. Put it in an alkali-resistant container so as not to come into contact with carbon dioxide, leave it for 3 days, and then filter it to obtain a potassium hydroxide solution. The resulting potassium hydroxide solution is stored in an alkali resistant container. As for the factor of the potassium hydroxide solution, take 25 ml of 0.5 mol / l hydrochloric acid in a triangular flask, add a few drops of the phenolphthalein solution, titrate with the potassium hydroxide solution, and the hydroxylation required for neutralization. Obtained from the amount of potassium solution. As the 0.5 mol / l hydrochloric acid, those prepared according to JIS K 8001-1998 are used.

(2) Operation (A) 1.0 g of this test sample is precisely weighed into a 200 ml round-bottom flask, and 5.0 ml of the above-mentioned acetylation reagent is accurately added to this using a whole pipette. At this time, if the sample is difficult to dissolve in the acetylation reagent, a small amount of special grade toluene is added to dissolve the sample.
Place a small funnel on the mouth of the flask and immerse the bottom of the flask about 1 cm in a glycerin bath at about 97 ° C. to heat it. At this time, in order to prevent the temperature of the neck of the flask from rising due to the heat of the bath, it is preferable to cover the base of the neck of the flask with thick paper having a round hole.
After 1 hour, remove the flask from the glycerin bath and allow to cool. After allowing to cool, add 1 ml of water from the funnel and shake to hydrolyze acetic anhydride. The flask is heated again in a glycerin bath for 10 minutes for further complete hydrolysis. After allowing to cool, wash the walls of the funnel and flask with 5 ml of ethyl alcohol.
Add a few drops of the phenolphthalein solution as an indicator and titrate with the potassium hydroxide solution. The end point of the titration is when the light red color of the indicator continues for about 30 seconds.

(B) Blank test Perform the same titration as the above operation except that the sample is not used.

(3) Substitute the obtained result into the following formula to calculate the hydroxyl value.
A = [{(BC) x 28.05 x f} / S] + D
Here, A: hydroxyl value (mgKOH / g), B: addition amount of potassium hydroxide solution in blank test (ml), C: addition amount of potassium hydroxide solution in this test (ml), f: potassium hydroxide Solution factor, S: sample (g), D: acid value of sample (mgKOH / g).

[Measurement of shell layer thickness of toner particles]
The thickness of the shell layer of the toner particles can be determined as follows by observing the cross section with a transmission electron microscope (TEM).
Using an osmium plasma coater (filgen, OPC80T), an Os film (5 nm) and a naphthalene film (20 nm) were applied to the toner as a protective film, and the toner was embedded with a photocurable resin D800 (JEOL Ltd.) and then ultra-supercharged. A toner particle cross section having a film thickness of 60 nm (or 70 nm) was prepared at a cutting speed of 1 mm / s by an ultrasonic ultramicrotome (Leica, UC7).
The obtained cross section was stained for 15 minutes in a RuO4 gas 500 Pa atmosphere using a vacuum electron staining apparatus (filgen, VSC4R1H), and STEM observation was performed using TEM (JEOL, JEM2800).
The STEM probe size was 1 nm and the image size was 1024 x 1024 pixel. The obtained image is binarized (threshold value 120/255 steps) by the image processing software "Image-Pro Plus (manufactured by Media Cybernetics)". The shell in the toner particles is extracted by binarizing the obtained image, and the thickness thereof is measured. For one toner particle, the thickness is measured at four points on the top, bottom, left, and right, and the average shell thickness per toner particle is calculated. The same measurement was performed on 20 randomly selected toner particles, and the average value was calculated to obtain the thickness of the shell layer of the toner particles in the present invention.

[Measurement of BET specific surface area of inorganic fine particles]
The BET specific surface area of the inorganic fine particles was measured according to JIS Z8830 (2001). The specific measurement method is as follows.
As the measuring device, an "automatic specific surface area / pore distribution measuring device TriStar3000 (manufactured by Shimadzu Corporation)", which employs a gas adsorption method based on a constant volume method, was used. The setting of measurement conditions and the analysis of measurement data are performed using the dedicated software "TriStar3000 Version4.00" attached to this device, and a vacuum pump, nitrogen gas pipe, and helium gas pipe are connected to the device. Nitrogen gas was used as the adsorbed gas, and the value calculated by the BET multipoint method was used as the BET specific surface area of the inorganic fine particles in the present invention.

The BET specific surface area was calculated as follows.
First, nitrogen gas was adsorbed on the inorganic fine particles, and the equilibrium pressure P (Pa) in the sample cell at that time and the nitrogen adsorption amount Va (mol g ^-1 ) of the external additive were measured. Then, the horizontal axis is the relative pressure Pr, which is the value obtained by dividing the equilibrium pressure P (Pa) in the sample cell by the saturated vapor pressure Po (Pa) of nitrogen, and the vertical axis is the nitrogen adsorption amount Va (mol g ^-1 ). The adsorption isotherm was obtained. Next, the adsorption amount Vm (mol g ^-1 ) of the single molecule layer, which is the adsorption amount required to form the single molecule layer on the surface of the external additive, was obtained by applying the following BET formula.
Pr / Va (1-Pr) = 1 / (Vm × C) + (C-1) × Pr / (Vm × C)
(Here, C is a BET parameter, which is a variable that varies depending on the measurement sample type, adsorbed gas type, and adsorption temperature.)
The BET formula is interpreted as a straight line with a slope of (C-1) / (Vm × C) and an intercept of 1 / (Vm × C), where Pr is the X-axis and Pr / Va (1-Pr) is the Y-axis. You can (this straight line is called the BET plot).
Slope of a line = (C-1) / (Vm × C)
Straight line intercept = 1 / (Vm × C)
When the measured value of Pr and the measured value of Pr / Va (1-Pr) are plotted on a graph and a straight line is drawn by the least squares method, the slope of the straight line and the intercept value can be calculated. Vm and C can be calculated by solving the simultaneous equations of the slope and the intercept using these values.
Further, the BET specific surface area S (m ² / g) of the inorganic fine particles is calculated from the Vm and the molecular occupied cross-sectional area of the nitrogen molecule (0.162 nm ² ) calculated above based on the following formula.
S = Vm x N x 0.162 x ^10-18
(Here, N is Avogadro's number (Mole ^-1 ).)

The measurement using this device follows the "TriStar3000 Instruction Manual V4.0" attached to the device, but specifically, the measurement was performed by the following procedure.
A tare of a special glass sample cell (stem diameter 3/8 inch, volume about 5 ml) that had been thoroughly washed and dried was precisely weighed. Then, using a funnel, about 0.1 g of an external additive was placed in this sample cell.
The sample cell containing the inorganic fine particles was set in a "pretreatment device Bacuprep 061 (manufactured by Shimadzu Corporation)" in which a vacuum pump and a nitrogen gas pipe were connected, and vacuum degassing was continued at 23 ° C. for about 10 hours. At the time of vacuum degassing, the valve was gradually degassed so that the inorganic fine particles were not sucked into the vacuum pump. The pressure in the cell gradually decreased with degassing, and finally reached about 0.4 Pa (about 3 mitol). After the vacuum degassing was completed, nitrogen gas was gradually injected to return the inside of the sample cell to atmospheric pressure, and the sample cell was removed from the pretreatment device. Then, the mass of this sample cell was precisely weighed, and the exact mass of the external additive was calculated from the difference from the tare. At this time, the sample cell was covered with a rubber stopper during weighing so that the external additive in the sample cell would not be contaminated with moisture in the atmosphere.

Next, a dedicated "isothermal jacket" was attached to the stem portion of the sample cell containing the inorganic fine particles. Then, a dedicated filler rod was inserted into the sample cell, and the sample cell was set in the analysis port of the device. The isothermal jacket is a tubular member having a porous material on the inner surface and an impermeable material on the outer surface, which can suck up liquid nitrogen to a certain level by capillarity.

Subsequently, the free space of the sample cell including the connecting device was measured. In the free space, the volume of the sample cell was measured using helium gas at 23 ° C., and then the volume of the sample cell after cooling the sample cell with liquid nitrogen was also measured using helium gas. It was calculated by converting from the difference in volume of. Further, the saturated vapor pressure Po (Pa) of nitrogen is automatically measured separately by using the Po tube built in the apparatus.

Next, after vacuum degassing in the sample cell, the sample cell was cooled with liquid nitrogen while continuing the vacuum degassing. Then, nitrogen gas was introduced stepwise into the sample cell to adsorb nitrogen molecules on the toner. At this time, since the adsorption isotherm can be obtained by measuring the equilibrium pressure P (Pa) at any time, the adsorption isotherm was converted into a BET plot. The points of the relative pressure Pr for collecting data were set to 0.05, 0.10, 0.15, 0.25, 0.25, and 0.30, for a total of 6 points. A straight line was drawn from the obtained measurement data by the method of least squares, and Vm was calculated from the slope and intercept of the straight line. Further, using this value of Vm, the BET specific surface area of the inorganic fine particles was calculated as described above.

Hereinafter, the present invention will be described with reference to Examples and the like. However, the description of this embodiment does not limit the technical scope of the present invention.

<Production example of crystalline resin A1>
Hexanediol: 30.4 parts by mass (46.0 mol%)
Dodecanedioic acid: 69.6 parts by mass (54.0 mol%)
The above materials were weighed in a cooling tube, a stirrer, a nitrogen introduction tube, and a reaction vessel equipped with a thermocouple. Next, the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and the reaction was carried out for 3 hours while stirring at a temperature of 140 ° C.
-Tin 2-ethylhexanoate: 0.5 parts by mass After that, the above material was added, the pressure in the reaction vessel was lowered to 8.3 kPa, and the reaction was carried out for 4 hours while maintaining the temperature at 200 ° C. to crystallize the resin A1. Got The obtained crystalline resin A1 had a weight average molecular weight of Mw12000, an acid value of 33.0 mgKOH / g, and a hydroxyl value of 3.0 mgKOH / g.

<Production example of crystalline resin A2>
Hexanediol: 32.5 parts by mass (47.0 mol%)
Dodecanedioic acid: 67.5 parts by mass (50.0 mol%)
-Tin 2-ethylhexanoate: 0.5 parts by mass The above materials were weighed in a cooling tube, a stirrer, a nitrogen introduction tube, and a reaction vessel equipped with a thermocouple. After replacing the inside of the flask with nitrogen gas, the temperature was gradually raised while stirring, and the reaction was carried out for 3 hours while stirring at a temperature of 140 ° C.
Next, the above materials were added, the pressure in the reaction vessel was lowered to 8.3 kPa, and the reaction was carried out for 4 hours while maintaining the temperature at 200 ° C.
Further, the pressure in the reaction vessel was gradually released and returned to normal pressure, then 5.0 parts by mass (3.0 mol%) of stearic acid was added, and the reaction was carried out at 200 ° C. for 2 hours under normal pressure.
Then, the inside of the reaction vessel was reduced to 5 kPa or less and reacted at 200 ° C. for 3 hours to obtain a crystalline polyester resin A2. The obtained crystalline resin A2 had a weight average molecular weight of Mw12000, an acid value of 26.0 mgKOH / g, and a hydroxyl value of 2.0 mgKOH / g.

<Production examples of crystalline resins A3 to A10>
In the production example of the crystalline resin A2, the reaction was carried out in the same manner except that the monomers used were changed as shown in Table 1, to obtain crystalline resins A3 to A10. Table 1 shows the compositions and physical properties of the obtained crystalline resins A3 to A10.

<Production example of amorphous resin B1>
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane (BPA-PO): 68.2 parts by mass (49.0 mol%)
-Terephthalic acid: 24.7 parts by mass (38.0 mol%)
-Adipic acid: 5.7 parts by mass (10.0 mol%)
-Benzoic acid: 1.4 parts by mass (3.0 mol%)
-Titanium tetrabutoxide (esterification catalyst): 0.5 parts by mass The above materials were weighed in a cooling tube, a stirrer, a nitrogen introduction tube, and a reaction vessel equipped with a thermocouple. Next, the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and the reaction was carried out for 5 hours while stirring at a temperature of 200 ° C.
Further, the pressure in the reaction vessel was lowered to 8.3 kPa, maintained for 1 hour, cooled to 160, and returned to atmospheric pressure (first reaction step).
-Tert-Butylcatechol (polymerization inhibitor): 0.1 part by mass Then, the above material was added, the pressure in the reaction vessel was lowered to 8.3 kPa, and the reaction was carried out for 1 hour while maintaining the temperature at 180 ° C., ASTM D36. After confirming that the softening point measured according to −86 reached the temperature of 88 ° C., the temperature was lowered to stop the reaction, and the amorphous resin B1 was obtained. The glass transition point of the amorphous resin B1 was 49 ° C., the acid value was 6.0 mgKOH / g, and the hydroxyl value was 32.0 mgKOH / g.

<Production example of amorphous resins B2 to B5>
In the production example of the amorphous resin B1, the reaction was carried out in the same manner except that the monomers used were changed as shown in Table 2, to obtain amorphous resins B2 to B5. Table 2 shows the composition and physical properties of the obtained amorphous resins B2 to B5.

<Production example of amorphous resin B6>
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane (BPA-PO): 71.4 parts by mass (55.0 mol%)
-Terephthalic acid: 22.4 parts by mass (37.0 mol%)
-Titanium tetrabutoxide (esterification catalyst): 0.5 parts by mass The above materials were weighed in a cooling tube, a stirrer, a nitrogen introduction tube, and a reaction vessel equipped with a thermocouple. Next, the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and the reaction was carried out for 2 hours while stirring at a temperature of 200 ° C.
Further, the pressure in the reaction vessel was lowered to 8.3 kPa, maintained for 1 hour, cooled to 160, and returned to atmospheric pressure (first reaction step).
Trimellitic acid anhydride: 6.2 parts by mass (8.0 mol%)
-Tert-Butylcatechol (polymerization inhibitor): 0.1 part by mass Then, the above material was added, the pressure in the reaction vessel was lowered to 8.3 kPa, and the reaction was carried out for 15 hours while maintaining the temperature at 200 ° C., ASTM D36. After confirming that the softening point measured according to −86 reached 140 ° C., the temperature was lowered to stop the reaction (second reaction step), and an amorphous resin B6 was obtained. Table 2 shows the composition and physical properties of the obtained amorphous resin B6.

<Production example of amorphous resin B7>
100 parts by mass of xylene, 97.5 parts by mass of styrene, and 2.5 parts by mass of acrylic acid were charged in a reaction vessel and mixed, and the temperature of the obtained mixed solution was raised to 75 ° C. Under a nitrogen atmosphere, 5.0 parts by mass of tert-butyl hydroperoxide, which is a radical polymerization initiator, was dissolved in 10.0 parts by mass of xylene, and the mixture was added dropwise to the mixed solution over about 30 minutes. Further, the mixed solution was kept warm at that temperature for 5 hours to complete the radical polymerization reaction. Further, the pressure was reduced while heating the mixture, and 60.0 parts by mass of xylene was removed from the solvent to obtain a reaction solution.
On the other hand, 500.0 parts by mass of methanol was charged into a container equipped with a stirring blade and stirred. The reaction solution was added dropwise thereto over 1 hour, and the obtained precipitate was filtered and washed, and then dried to obtain an amorphous resin B7. The glass transition point was 55 ° C., the softening point was 110 ° C., and the acid value was 17 mgKOH / g.

<Release agent>
The release agent used in the present invention was Fischer-Tropsch wax, and the peak temperature of the maximum endothermic peak was 90 ° C., and the acid value was 0 mgKOH / g.

<Production example of a dispersion liquid of thermosetting resin C>
1200 parts by mass of water, 5 parts by mass of sodium persulfate, 70 parts by mass of 2-vinyl-2-oxazoline and 30 parts by mass of methyl acrylate were charged in a reaction vessel and heated to 60 ° C. under a nitrogen atmosphere. After stirring was continued for 8 hours to complete the reaction, the mixture was cooled to obtain a dispersion of 10% thermosetting resin C. The weight average molecular weight of the thermosetting resin C was 50,000.

<Production example of dispersion liquid of amorphous resin B7>
400 parts by mass of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.), 100 parts by mass of the amorphous resin B7, and 0.7 parts by mass of the anionic surfactant Neogen RK (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) were mixed and dissolved. Next, 20.0 g of 1 mol / L ammonia water was added, and the ultrafast stirrer T.I. K. The mixture was stirred at 4000 rpm using Robomix (manufactured by Primix). Further, 700 g of ion-exchanged water was added at a rate of 8 g / min to precipitate amorphous resin fine particles. Then, tetrahydrofuran was removed using an evaporator, and the concentration was adjusted with ion-exchanged water to obtain an aqueous dispersion (acrystalline resin fine particle B7 dispersion) having a concentration of 10% of the amorphous resin fine particles B7. This dispersion was used to form the shell layer of the toner 19 shown in Table 3.

<Manufacturing example 1 of toner>
<Creation of toner core>
・ 10 parts by mass of crystalline resin A1 ・ 70 parts by mass of amorphous resin B1 ・ 30 parts by mass of amorphous resin B6 ・ 4 parts by mass of mold release agent ・ C.I. I. Pigment Blue 15:35 parts by mass, 3,5-di-t-aluminum salicylate compound 0.5 parts by mass The above material is rotated using a Henshell mixer (FM-75 type, manufactured by Nippon Coke Industries Co., Ltd.). After mixing at 20s ^-1 and a rotation time of 5 min, the mixture was kneaded at a discharge temperature of 140 ° C. using a twin-screw kneader (PCM-30 type, manufactured by Ikegai Co., Ltd.) set at a temperature of 130 ° C. The obtained kneaded product was cooled and coarsely pulverized with a hammer mill to 1 mm or less to obtain a coarsely crushed product. The obtained coarse crushed product was finely pulverized with a mechanical crusher (T-250, manufactured by Freund Turbo Co., Ltd.). Further, using Faculti F-300 (manufactured by Hosokawa Micron Co., Ltd.), classification was performed to obtain a toner core 1. The operating conditions were a classification rotor rotation speed of 130s ^-1 and a distributed rotor rotation speed of 120s ^-1 .

<Shell layer forming process>
A 3-necked flask with a capacity of 1 L equipped with a stirring blade is set in a water bath, 100 parts by mass of toner core 1 and 300 ml of an aqueous solution of 2-propanol 20 mass% are added into the flask, and the contents of the flask are charged at a rotation speed of 150 rpm. The temperature inside the flask was raised to 60 ° C. with stirring. Subsequently, the thermosetting resin C dispersion was added into the flask. The amount added was such that the thickness of the shell layer became the value shown in Table 1. Then, after continuing stirring for 30 minutes while maintaining 60 ° C., the dispersion liquid was filtered, washed and dried to obtain toner particles 1.

<External process>
1.0 part by mass (BET: 25 m ² / g) of hydrophobic silica fine particles surface-treated with 4% by mass of hexamethyldisilazane and 1 part of hydrophobic silica (BET: 200 m ² / g) on 100 parts by mass of toner particles 1. .0 parts and 1.0 part of titanium oxide fine particles (BET: 80 m ² / g) surface-treated with isobutyltrimethoxysilane were rotated by a Henschel mixer (FM-75 type, manufactured by Mitsui Mine Co., Ltd.) at a rotation speed of 30 s. ^-1 , rotation time 5 min. Toner 1 was obtained. The weight average particle size (D4) of the toner 1 was 6.5 μm, and the average circularity of the toner was 0.96.

<Manufacturing example of toners 2 to 24>
In the production example of the toner 1, the toners 2 to 24 are prepared in the same manner except that the thicknesses of the crystalline resin A, the amorphous resin B, the resin of the shell layer, and the shell layer are changed as shown in Table 3. Obtained. The thickness of the shell layer tended to increase as the amount of the thermosetting resin C added increased.

<Manufacturing example of magnetic core particle 1>
-Step 1 (Weighing / mixing step):
Fe ₂ O ₃ 62.7 parts by mass MnCO ₃ 29.5 parts by mass Mg (OH) ₂ 6.8 parts by mass SrCO ₃ 1.0 part by mass The ferrite raw material was weighed so as to have the above composition ratio. Then, it was pulverized and mixed for 5 hours with a dry vibration mill using stainless beads having a diameter of 1/8 inch.

-Step 2 (temporary firing step):
The obtained pulverized product was made into pellets of about 1 mm square by a roller compactor. Coarse powder was removed from the pellets with a vibrating sieve having an opening of 3 mm, and then fine powder was removed with a vibrating sieve having an opening of 0.5 mm. It was calcined at a temperature of 1000 ° C. for 4 hours at 01% by volume) to prepare a calcined ferrite. The composition of the obtained calcined ferrite is as follows.
(MnO) a (MgO) b (SrO) c (Fe ₂ O ₃ ) d
In the above formula, a = 0.257, b = 0.117, c = 0.007, d = 0.393.

-Step 3 (crushing step):
After crushing to about 0.3 mm with a crusher, 30 parts by mass of water was added to 100 parts by mass of calcined ferrite using zirconia beads having a diameter of 1/8 inch, and the mixture was crushed with a wet ball mill for 1 hour. The slurry was pulverized with a wet ball mill using alumina beads having a diameter of 1/16 inch for 4 hours to obtain a ferrite slurry (a finely pulverized product of calcined ferrite).

・ Process 4 (granulation process):
To 100 parts by mass of calcined ferrite, 1.0 part by mass of ammonium polycarboxylate as a dispersant and 2.0 parts by mass of polyvinyl alcohol as a binder were added to the ferrite slurry, and a spray dryer (manufacturer: Okawara Kakoki) was used. It was granulated into spherical particles. After adjusting the particle size of the obtained particles, the particles were heated at 650 ° C. for 2 hours using a rotary kiln to remove organic components of the dispersant and the binder.

-Step 5 (firing step):
In order to control the firing atmosphere, the temperature was raised from room temperature to a temperature of 1300 ° C. in 2 hours under a nitrogen atmosphere (oxygen concentration 1.00% by volume) in an electric furnace, and then firing was performed at a temperature of 1150 ° C. for 4 hours. Then, over 4 hours, the temperature was lowered to 60 ° C., the nitrogen atmosphere was returned to the atmosphere, and the mixture was taken out at a temperature of 40 ° C. or lower.

・ Process 6 (sorting process):
After crushing the agglomerated particles, the low magnetic force product is cut by magnetic beneficiation and sieved with a sieve having a mesh size of 250 μm to remove coarse particles. Magnetic core particles 1 were obtained.

<Adjustment of coating resin 1>
Cyclohexyl methacrylate monomer 26.8% by mass
Methyl methacrylate monomer 0.2% by mass
Methyl Methacrylate Macromonomer 8.4% by Mass
(Macrmonomer having a methacryloyl group at one end and having a weight average molecular weight of 5000)
Toluene 31.3% by mass
Methyl ethyl ketone 31.3% by mass
Azobisisobutyronitrile 2.0% by mass
Of the above materials, cyclohexylmethacrylate, methylmethacrylate, methylmethacrylate macromonomer, toluene, and methylethylketone are added to a four-port separable flask equipped with a reflux condenser, a thermometer, a nitrogen introduction tube, and a stirrer, and nitrogen gas is added. Was introduced to give a sufficient nitrogen atmosphere, the mixture was heated to 80 ° C., azobisisobutyronitrile was added, and the mixture was refluxed for 5 hours for polymerization. Hexane was injected into the obtained reaction product to precipitate and precipitate a copolymer, and the precipitate was filtered off and then vacuum dried to obtain a coated resin 1. The obtained coating resin 1 was dissolved in 30 parts by mass, 40 parts by mass of toluene, and 30 parts by mass of methyl ethyl ketone to obtain a polymer solution 1 (solid content: 30% by mass).

<Preparation of coating resin solution 1>
Polymer solution 1 (resin solid content concentration 30%) 33.3% by mass
Toluene 66.4% by mass
Carbon black (Regal330; manufactured by Cabot) 0.3% by mass
(Primary particle size 25 nm, nitrogen adsorption specific surface area 94 m ² / g, DBP oil absorption 75 ml / 100 g)
Was dispersed in a paint shaker for 1 hour using zirconia beads having a diameter of 0.5 mm. The obtained dispersion was filtered through a 5.0 μm membrane filter to obtain a coating resin solution 1.

<Manufacturing example of magnetic carrier 1>
(Resin coating process):
The coated resin solution 1 was added to a vacuum degassing type kneader maintained at room temperature so as to be 2.5 parts by mass as a resin component with respect to 100 parts by mass of the packed core particles 1. After the addition, the mixture was stirred at a rotation speed of 30 rpm for 15 minutes, the solvent was volatilized above a certain level (80% by mass), the temperature was raised to 80 ° C. while mixing under reduced pressure, toluene was distilled off over 2 hours, and then the mixture was cooled. The obtained magnetic carrier is separated into low magnetic force products by magnetic beneficiation, passed through a sieve having an opening of 70 μm, and then classified by a wind power classifier. I got 1.

<Manufacturing example of two-component developer>
Mix the toners 1 to 24 and the magnetic carrier 1 with a V-type mixer (V-10 type: Tokuju Seisakusho Co., Ltd.) at 0.5s ^-1 and a rotation time of 5 min so that the toner concentration becomes 8.0% by mass. , Two-component developer 1 to 24 were obtained.

<Evaluation>
Using the above-mentioned two-component developer 1, the following low-temperature fixing property evaluation, heat-resistant storage property evaluation, and charge retention property evaluation were performed.
Evaluation is based on the following evaluation methods, and the results are shown in Table 4.

[Evaluation 1. Low temperature fixability evaluation]
The full-color copying machine imagePress C800 manufactured by Canon Inc. was modified so that the fixing temperature and the process speed could be freely set, and the fixing temperature region of the two-component developer 1 was tested. The image is adjusted so that the amount of toner on the paper is 1.2 mg / cm ² in a single color mode under normal temperature and humidity environment (temperature 23 ° C, relative humidity 50% or more and 60% or less), and the printing ratio is 25%. Output unfixed. As the evaluation paper, copy paper GF-C081 (A4, basis weight 81.4 g / m ² , sold by Canon Marketing Japan Co., Ltd.) was used.
After that, in a low temperature and low humidity environment (temperature 15 ° C, relative humidity 10% or less), the process speed is set to 450 mm / sec, the fixing temperature is increased by 2.5 ° C in order from 120 ° C, and the lower limit temperature at which no offset occurs. Was set as the fixable temperature.
(Evaluation criteria for fixable temperature)
A: Less than 150 ° C (very excellent)
B: 150 ° C or higher and lower than 155 ° C (good)
C: 155 ° C or higher and lower than 160 ° C (the level at which the effect of the present invention is obtained).
D: 160 ° C or higher (not acceptable in the present invention)
The evaluation results are shown in Table 5.

[Evaluation 2. Heat resistance evaluation]
5 g of toner was placed in a 100 cc resin cup and left in a constant temperature bath (55 ° C. 50%) with variable temperature and humidity for 10 hours, and the cohesiveness of the toner was evaluated after leaving. For the cohesiveness, the residual ratio of the remaining toner was used as an evaluation index when the powder tester PT-X manufactured by Hosokawa Micron Co., Ltd. was shaken with a mesh having an opening of 150 μm for 10 seconds at an amplitude of 0.5 mm. C or higher was judged to be good.
(Evaluation criteria)
A: Residual rate less than 2.0% B: Residual rate 2.0% or more and less than 5.0% C: Residual rate 5.0% or more and less than 10.0% D: Residual rate 10.0% or more

[Evaluation 3: Evaluation of charge retention]
Using a Canon full-color copying machine imageRUNNER ADVANCE C9075PRO, images were output in a high temperature and high humidity environment (30 ° C./80% Rh) and at room temperature and normal humidity (23 ° C./50% Rh). The output image is a vertical band image with a width of 10 cm and a width of 4 A of cyan in a single color mode, and the reflection density of cyan on paper is adjusted to 1.35. As the evaluation paper, copy paper GF-C081 (A4, basis weight 81.4 g / m ² , sold by Canon Marketing Japan Co., Ltd.) was used. Then, the developer was taken out and left for 150 hours, the main body was started up, the developer was returned to the main body, and the same image was output again under the same development conditions. The reflection density of the obtained output image was measured by averaging 9 locations using an X-Rite color reflection densitometer (500 series: manufactured by X-Rite), and compared with the reflection density before and after leaving. It was evaluated according to the criteria of.
(Evaluation criteria: Difference in reflection density of output image before and after leaving)
A: Less than Δ0.06 (very good)
B: Δ0.06 or more and less than Δ0.12 (good)
C: Δ0.12 or more and less than Δ0.18 (the level at which the effect of the present invention is obtained) D: Δ0.18 or more (not acceptable in the present invention)

<Examples 2 to 16 and Comparative Examples 1 to 8>
In Example 1, the evaluation was carried out in the same manner except that the two-component developer used for the evaluation was changed to the two-component developer shown in Table 4. The evaluation results are shown in Table 4.

Claims (8)

A toner having toner particles having a core-shell structure in which the surface of the toner core is covered with a shell layer.
The toner core contains a crystalline resin A and an amorphous resin B, and contains the crystalline resin A and the amorphous resin B.
The crystalline resin A has a carboxy group and has a carboxy group.
The acid value of the crystalline resin A is 10.0 mgKOH / g or more and 50.0 mgKOH / g or less.
The hydroxyl value of the crystalline resin A is 20.0 mgKOH / g or less, and the hydroxyl value is 20.0 mgKOH / g or less.
The shell layer contains a thermosetting resin C having a functional group capable of reacting with the carboxy group.
The interface between the toner core and the shell layer is
With the carboxy group of the crystalline resin A,
The crystalline resin A has a resin component formed by a cross-linking reaction with the functional group of the thermosetting resin C having a functional group capable of reacting with the carboxy group.
A toner characterized in that the thickness of the shell layer is 3 nm or more and 200 nm or less. The acid value of the amorphous resin B is 20.0 mgKOH / g or less, and the acid value is 20.0 mgKOH / g or less.
The toner according to claim 1, wherein the amorphous resin B has a hydroxyl value of 40.0 mgKOH / g or less. The toner according to claim 1 or 2, wherein the resin component has a structural unit derived from an oxazoline group formed by the crosslinking reaction with the carboxy group. The toner according to any one of claims 1 to 3, wherein the crystalline resin A and the amorphous resin B are polyester resins. The toner according to any one of claims 1 to 4, wherein the acid value of the crystalline resin A is 25.0 mgKOH / g or more and 40.0 mgKOH / g or less. The toner according to any one of claims 1 to 5, wherein the thickness of the shell layer is 3 nm or more and 20 nm or less. The invention according to any one of claims 1 to 6, wherein the weight average molecular weight Mw of the resin component formed by the cross-linking reaction between the crystalline resin A and the thermosetting resin C is 34,000 or more and 200,000 or less. The toner described. A method for producing toner having toner particles having a core-shell structure in which the surface of the toner core is covered with a shell layer.
A step of reacting a crystalline resin A contained in the toner core with a shell material in an aqueous medium to form the shell layer covering the surface of the toner core to obtain toner particles is included.
The shell material has a thermosetting resin C having an oxazoline group.
The toner core contains the crystalline resin A and the amorphous resin B, and the toner core contains the crystalline resin A and the amorphous resin B.
The crystalline resin A contains a carboxy group and has
The acid value of the crystalline resin A is 10.0 mgKOH / g or more and 50.0 mgKOH / g or less.
The hydroxyl value of the crystalline resin A is 20.0 mgKOH / g or less, and the hydroxyl value is 20.0 mgKOH / g or less.
The shell layer contains a resin component containing a unit having an oxazoline group and a unit having an amide bond.
The amide bond is formed by reacting the oxazoline group of the thermosetting resin C contained in the shell material with the carboxy group of the crystalline resin A contained in the toner core to form a toner. ..