JP6864435B2 - Toner for electrostatic latent image development - Google Patents

Description

The present invention relates to a toner for electrostatic latent image development. More specifically, the present invention is an electrostatic latent image capable of achieving both low-temperature fixability and heat-resistant storage while suppressing white spot image defects after long-term use and maintaining good transferability due to the spacer effect. Regarding developing toner.

Conventionally, in an electrophotographic image forming method for forming a visible image by an electrophotographic method, a toner image formed by an electrostatic latent image developing toner (hereinafter, also simply referred to as “toner”) on a transfer medium such as paper. Is being established. As a method for fixing the toner image, a thermal roller fixing method is widely used in which a transfer medium on which a toner image is formed is passed between a heating roller and a pressure roller to be fixed. The heating roller is required to have a high heat capacity in order to secure the fixability in this heat roller fixing method, that is, the adhesiveness of the toner to a transfer medium such as paper.

However, in recent years, from the viewpoint of measures to prevent global warming, there is an increasing demand for energy saving in electrophotographic image forming devices. For this reason, particularly in an electrophotographic image forming apparatus that employs a thermal roller fixing method, a technique for reducing the amount of heat required for fixing a toner image, that is, a technique for lowering the fixing temperature is being studied.
In order to lower the fixing temperature of the toner, it is necessary to lower the melting temperature and the melting viscosity of the binder resin constituting the toner base particles.
However, in order to lower the melting temperature and melting viscosity of the binder resin, lowering the glass transition point and molecular weight of the binder resin causes new problems such as deterioration of the heat-resistant storage property of the toner or the occurrence of a phenomenon called high temperature offset. ..

As a technique for solving this problem, a technique for improving the low-temperature fixability of the toner by using a crystalline resin and an amorphous resin in combination as the binder resin constituting the toner matrix particles has been proposed.

On the other hand, it has also been proposed to improve chargeability, developability, and transferability by adding large-diameter resin particles having a high gel fraction by cross-linking as an external additive (see, for example, Patent Document 1). .).
However, as the printing progresses for a long period of time, when the above resin particles are used, the resin particles released from the toner are deposited on the cleaning blade portion and cannot be suppressed, and slips through, resulting in an image defect in which the portion is white. Problem has occurred.

Japanese Unexamined Patent Publication No. 2004-163612

The present invention has been made in view of the above problems and situations, and the problems to be solved are low-temperature fixability and heat resistance while suppressing white spot image defects after long-term use and maintaining good transferability due to the spacer effect. It is an object of the present invention to provide a toner for electrostatic latent image development capable of achieving both storage stability.

In order to solve the above problems, the present inventor has an electrostatic latent having a core particle coated with a specific coverage and an external additive made of a specific resin in the process of examining the cause of the problem. By using the toner for image development, the degree of desorption of the external additive can be suitably adjusted, and as a result, low-temperature fixing is performed while suppressing white spot image defects after long-term use and maintaining good transferability due to the spacer effect. We have found that we can provide a toner for electrostatic latent image development that can achieve both properties and heat-resistant storage properties, and have arrived at the present invention.
That is, the above-mentioned problem according to the present invention is solved by the following means.

1. 1. A toner for electrostatic latent image development containing toner matrix particles having a core-shell structure and an external additive.
The toner base particles have core particles containing a vinyl resin and a shell that covers the surface of the core particles within a coverage range of 60 to 99%.
The shell contains an amorphous polyester resin and
The external additive contains crosslinked vinyl-based resin particles,
The cross-linked vinyl resin particles, number average particle diameter Ri range der of 30 to 300 nm,
The crosslinked vinyl-based resin particles contain a crosslinked resin containing a structural unit derived from a crosslinkable vinyl monomer and a non-crosslinkable resin containing a structural unit derived from a non-crosslinkable vinyl monomer.
The non-crosslinkable vinyl monomer is styrene and methyl methacrylate, and the content of the structural unit derived from the cross-linkable vinyl monomer is 100% by mass based on the non-crosslinkable vinyl monomer. an electrostatic latent image developing toner, characterized in der Rukoto the range of 5 to 30 mass%.

2. The toner for electrostatic latent image development according to item 1, wherein the shell covers the surface of the core particles within a coverage range of 70 to 95%.

3. 3. The toner for electrostatic latent image development according to item 1 or 2, wherein the core particles contain a crystalline resin.

4. The toner for electrostatic latent image development according to item 3, wherein the crystalline resin contains a crystalline polyester resin.

5. The toner for electrostatic latent image development according to item 3 or 4, wherein the crystalline resin is a crystalline resin formed by bonding a vinyl-based polymerized segment and a polyester polymerized segment.

6. The toner for electrostatic latent image development according to any one of items 1 to 5, wherein the average particle size of the crosslinked vinyl resin particles is in the range of 50 to 200 nm.

7. Items 1 to 6 are characterized in that the crosslinked vinyl-based resin particles are contained in the range of 0.05 to 3.0% by mass with respect to the entire toner for electrostatic latent image development. The toner for electrostatic latent image development according to any one of the above items.

By the above means of the present invention, electrostatic latent image development capable of achieving both low-temperature fixability and heat-resistant storage while suppressing white spot image defects after long-term use and maintaining good transferability due to the spacer effect. Toner can be provided.
Although the mechanism of expression or mechanism of action of the effect of the present invention has not been clarified, it is inferred as follows.

Since the crosslinked vinyl resin particles are attached to the toner base particles in the toner bottle, the heat-resistant storage property is high. However, the crosslinked vinyl-based resin particles are desorbed after mixing with the carrier, so that the unfixed image on the paper is easily fixed at a low temperature. Therefore, it is considered that it is advantageous for low-temperature fixing that the crosslinked vinyl-based resin particles are easily separated from the toner. Since the external additive such as silica particles has a high specific gravity, it is more difficult to remove than the crosslinked vinyl-based resin particles, and the above-mentioned effect is not obtained.

However, when the crosslinked vinyl-based resin particles are easily desorbed from the toner, the desorbed crosslinked vinyl-based resin particles accumulate in the nip portion between the photoconductor and the cleaning blade. When the accumulated crosslinked vinyl resin exceeds a certain threshold value, the cleaning blade is pushed up and comes off. As a result, since the portion is not developed by the toner, white spots appear and image defects (hereinafter, also referred to as “white spot image defects”) occur. That is, in order to suppress white spots, it is considered that the crosslinked vinyl-based resin particles should be hard to be separated from the toner.

Further, when the crosslinked vinyl-based resin particles are contained in the toner, they exert a spacer effect (the contact area between the toner and the photoconductor can be reduced) and can suppress the burial of the external additive particles, so that the developer is charged. It stabilizes the sex and can improve the transferability.
However, when the crosslinked vinyl-based resin particles are easily detached from the toner, it becomes difficult to obtain the spacer effect of the crosslinked vinyl-based resin particles, and a smaller external additive other than the crosslinked vinyl-based resin particles is used on the surface of the toner matrix particles. By burying in, the improvement in transferability is reduced. That is, in order to improve the transferability, it is considered that the crosslinked vinyl-based resin particles should be hard to be separated from the toner.

As described above, if the crosslinked vinyl-based resin particles, which are external additives, are easily desorbed from the toner, it is advantageous for low-temperature fixing, but it is disadvantageous for white spot suppression and transferability. It is considered important to appropriately control the ease of separation in order to improve transferability, low-temperature fixability, and heat-resistant storage property while suppressing whiteout image defects.

Here, in general, the crosslinked vinyl-based resin has a higher adhesion rate to the amorphous polyester resin than the vinyl-based resin.
Therefore, the present inventor uses an amorphous polyester resin having a high adhesion rate of the crosslinked vinyl resin for the shell, and adjusts the coverage of the shell with respect to the core particles to increase the amount of the crosslinked vinyl resin desorbed. It was inferred that the amount could be controlled to an appropriate level.
Based on such speculation, the present inventor has a shell containing an amorphous polyester resin that covers the surface of the core particles within a coverage range of 60 to 99%, and crosslinked vinyl resin particles. By adopting the contained external additive, the amount of the crosslinked vinyl resin desorbed can be made suitable, and as a result, white spot image defects after long-term use can be suppressed and good transferability due to the spacer effect can be maintained. We believe that we were able to achieve both low-temperature fixability and heat-resistant storage.

Schematic diagram showing an example of the cross-sectional structure of the toner matrix particles according to the present invention. An example of an electron microscope image of a cross section of a toner matrix particle according to the present invention.

The electrostatic latent image developing toner of the present invention is an electrostatic latent image developing toner containing a toner base particle having a core-shell structure and an external additive, and the toner base particle is vinyl-based. It has core particles containing a resin and a shell that coats the surface of the core particles within a coverage range of 60 to 99%. The shell contains an amorphous polyester resin, and the external additive is used. contains a crosslinked vinyl resin particles, the crosslinked vinyl resin particles, number average particle diameter Ri der range of 30 to 300 nm, the cross-linked vinyl resin particles are crosslinkable vinyl monomer It contains a crosslinked resin containing a structural unit derived from it and a non-crosslinkable resin containing a structural unit derived from a non-crosslinkable vinyl monomer, and the non-crosslinkable vinyl monomer is styrene and methyl methacrylate. and the content of structural units derived from the crosslinkable vinyl monomer, characterized in der Rukoto the range of 5 to 30 mass% with respect to the non-crosslinkable vinyl monomer 100 wt%. This feature is a technical feature common to or corresponding to the invention according to each claim.

In an embodiment of the present invention, when the shell covers the surface of the core particles within a coverage range of 70 to 95%, white spot image defects can be further suppressed, and further, transferability and low temperature can be achieved. It is preferable because the fixability can be further improved.

In the present invention, it is preferable that the core particles contain a crystalline resin, more preferably a crystalline polyester resin, because both heat-resistant storage property and low-temperature fixability can be more preferably achieved.
Further, if the crystalline resin is a crystalline resin in which a vinyl-based polymerized segment and a polyester-based polymerized segment are bonded, the dispersibility in the core particles containing the vinyl-based resin is good, so that the crystalline resin is fixed at a lower temperature. It is preferable.

In the present invention, it is preferable that the average particle size of the crosslinked vinyl resin particles is in the range of 50 to 200 nm because the spacer effect and the transferability after long-term use can be exhibited more satisfactorily.

In the present invention, it is the spacer effect and long-term use that the crosslinked vinyl-based resin particles are contained in the range of 0.05 to 3.0% by mass with respect to the entire toner for electrostatic latent image development. This is preferable because the effect of suppressing the white spot image afterwards can be further improved.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described in detail. In the present application, "~" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

≪Overview of Toner for Electrostatic Latent Image Development≫
The toner for electrostatic latent image development of the present invention is a toner for electrostatic latent image development containing a toner matrix particle having a core-shell structure and an external additive.
The toner base particles have core particles containing a vinyl resin and a shell that covers the surface of the core particles within a coverage range of 60 to 99%.
The shell contains an amorphous polyester resin and
The external additive contains crosslinked vinyl-based resin particles,
The cross-linked vinyl resin particles, number average particle diameter Ri der range of 30 to 300 nm, the cross-linked vinyl resin particles, and cross-linking resin containing a structural unit derived from a crosslinkable vinyl monomer, the non It contains a non-crosslinkable resin containing a structural unit derived from a crosslinkable vinyl monomer, the non-crosslinkable vinyl monomer is styrene and methyl methacrylate, and is derived from the crosslinkable vinyl monomer. the content of structural unit, said non-crosslinked toner for developing an electrostatic latent image, characterized in der Rukoto the range of 5 to 30 mass% relative to the vinyl monomer of 100 wt%.
It is characterized by that.
In the present invention, the "toner" means an aggregate of "toner particles".

≪Toner matrix particles≫
The toner base particles according to the present invention have a core-shell structure having core particles containing a vinyl resin and a shell that covers the surface of the core particles within a coverage range of 60 to 99%. The toner matrix particles according to the present invention become toner particles by adding the external additive according to the present invention.

<Core / shell structure>
As described above, in the present invention, the core-shell structure refers to a structure having core particles and a shell that covers the surface of the core particles within a coverage range of 60 to 99%.

"shell"
The shell contains an amorphous polyester resin and covers the surface of the core particles within a coverage range of 60 to 99%. When the coverage is 60% or more, the amount of desorption does not become too large, and white spot image defects can be suppressed and transferability can be improved. Further, when the shell coverage is 99% or less, the amount of desorption is not too small and the low temperature fixability is improved.
The coverage is more preferably in the range of 70 to 95%, which can further improve the effect of suppressing the white spot image defect, the effect of improving the transferability, and the effect of improving the low temperature fixability. Preferred from the point of view.
The coverage can be controlled by controlling the temperature at the time of fusing the shell particles aggregated on the surface of the core particles, adjusting the heating time, the amount of resin to be added, and the like.

[Coverage]
The coverage of the shell can be determined from the cross section of the toner particles observed as follows.

<Method of observing the cross section of toner particles>
A specific method for observing the cross section of the toner particles according to the present invention is as follows.
Equipment: Transmission electron microscope "JSM-7401F" (manufactured by JEOL Ltd.)
Sample: Section of toner particles stained with ruthenium tetroxide (RuO ₄ ) (section thickness: 60-100 nm)
Acceleration voltage: 30kV
Magnification: Range of 1000 to 20000 times Observation conditions: Transmission electron detector, bright field image

(Method for preparing a section of toner particles)
1 to 2 mg of toner is spread out in a 10 mL sample bottle _{, treated under ruthenium tetroxide (RuO 4} ) vapor dyeing conditions as shown below, and then photocurable resin (hereinafter, also referred to as “embedded resin”). It was dispersed and embedded in "D-800" (manufactured by Nippon Denshi Co., Ltd.) and photocured to form a block. Then, using a microtome equipped with diamond teeth, an ultrasliced sample having a thickness of 60 to 100 nm was cut out from the above block.

(Rutenium tetroxide treatment conditions)
The ruthenium tetroxide treatment is performed using a vacuum electron dyeing apparatus VSC1R1 (manufactured by Filgen Co., Ltd.). According to the equipment procedure, a sublimation chamber containing ruthenium tetroxide was installed in the main body of the dyeing apparatus, and after introducing toner or the above-mentioned ultrathin section into the staining chamber, the dyeing conditions with ruthenium tetroxide were room temperature (24 to 25 ° C.). Staining was performed under the conditions of a concentration of 3 (300 Pa) and a time of 10 minutes.

(Observation of dispersed particles)
Within 24 hours after staining, a cross-sectional image of the toner matrix particles was observed with an electron microscope "JSM-7401F" (manufactured by JEOL Ltd.).

FIG. 1 shows a schematic view of a cross-sectional structure when the toner matrix particles of the embodiment of the present invention are photographed with an electron microscope by the above-mentioned method.
As shown in FIG. 1, the toner matrix particle 1 includes a core particle 2 and a shell 3 composed of one or a plurality of shell regions 31 covering the surface of the core particle 2.
The thick solid line represents _{the interface I se} between the shell and the embedding resin. The thin solid line represents _{the interface Ice} between the core particles and the embedding resin. The dotted line represents _{the interface I cs} between the core particles and the shell.
Further, FIG. 2 is an example of a cross-sectional image of the observed toner matrix particles.
The measurement toner particle image is used for measurement by photographing 20 or more fields in which the diameter of the cross section of the toner particles is within the range of the median diameter (D50% diameter) ± 10% based on the volume of the toner particles.
As described above, in the present invention, it is preferable that the number of toner matrix particles for which a cross-section photograph is taken with an electron microscope is 20 or more.

(Measurement method of median diameter based on the volume of toner particles)
The median diameter (D50% diameter) based on the volume of the toner particles can be measured and calculated using a device in which a computer system for data processing is connected to "Multisizer 3 (manufactured by Beckman Coulter)".
As a measurement procedure, 0.02 g of toner particles are mixed with 20 mL of a surfactant solution (for the purpose of dispersing the toner particles, for example, a neutral detergent containing a surfactant component diluted 10-fold with pure water). After acclimation, ultrasonic dispersion is performed for 1 minute to prepare a toner particle dispersion liquid.
This toner particle dispersion is injected into a beaker containing ISOTON II (manufactured by Beckman Coulter) in a sample stand with a pipette until the measurement concentration is within the range of 5 to 10%, and the number of measuring machines is 25,000. Set to and measure.

The aperture diameter of the multisizer 3 is 100 μm. The frequency number is calculated by dividing the measurement range of 1 to 30 μm into 256, and the particle size of 50% from the one with the larger volume integration fraction is defined as the volume-based median diameter (D50% diameter).
The D50% diameter of the toner particles can be controlled by controlling the concentration of the flocculant, the amount of the organic solvent added, the fusion time, and the like in the above-mentioned production method.

<Measuring method of coverage>
The coverage of the shell in the toner matrix particles is calculated from the cross section of the toner matrix particles described above.
Specifically, the cross section of the toner matrix particles is photographed by an electron microscope JSM-7401F (manufactured by JEOL Ltd.) at an acceleration voltage of 30 kV at a magnification of 1000 to 20000, and the photographic image is photographed by the image processing analyzer LUZEX AP. (Manufactured by JEOL Ltd.) can be used to measure the length of the shell region and the embedding resin interface and the peripheral length of the cross section of the toner matrix particles.
The coverage of the shell is calculated by the following formula when the length of the interface between the shell region and the embedding resin is A and the cross-sectional peripheral length of the toner matrix particles is B.
(Coverage) = A / B x 100

The fact that the toner according to the present invention has a core-shell structure means that when observing the photograph of the cross-sectional structure of the toner taken, the core particles in which the colorant, the release agent, etc. are present are observed to be black (or gray). The shell region can be confirmed by observing it as an uncolored white region on the surface layer of the toner matrix particles. In the dyeing under this condition, the colorant cannot be identified when observing the cross section. In addition, the release agent is observed as a white part inside the core particles, and the crystalline polyester resin is observed inside the core particles as a darker black part (or dark gray) than the vinyl resin contained in the core particles. ..

[Shell area]
In the present invention, the shell region means that the surface of the core particles is covered with a thickness within the range of 0.7 to 18% with respect to the D50% diameter of the toner matrix particles, and the D50% diameter of the toner matrix particles. An interface having a length of 1.5% or more of the above, which is in contact with the surface of the core particles.
In the present invention, the shell is a layer composed of this shell region.

[Amorphous polyester resin]
_{The amorphous polyester resin has a glass transition point (T g} ) in the endothermic curve obtained by differential scanning calorimetry (DSC), but exhibits amorphousness without a melting point, that is, a clear endothermic peak at the time of temperature rise. Refers to polyester resin.

The amorphous polyester resin is obtained by a polycondensation reaction using a polyvalent carboxylic acid monomer (derivative) and a polyhydric alcohol monomer (derivative) as raw materials in the presence of an appropriate catalyst.
As the polyvalent carboxylic acid monomer derivative, for example, an alkyl ester of the polyvalent carboxylic acid monomer, an acid anhydride and an acid chloride can be used, and as the polyhydric alcohol monomer derivative, for example, an ester of the polyhydric alcohol monomer and Hydroxycarboxylic acid can be used.

Examples of the polyvalent carboxylic acid monomer include oxalic acid, succinic acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonandicarboxylic acid, decandicarboxylic acid, undecandicarboxylic acid, and dodecandicarboxylic acid. Fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimeric acid, tartrate acid, mucilage acid, phthalic acid, Isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o-phenylenediglycolic acid, Divalents such as diphenylacetic acid, diphenyl-p, p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracendicarboxylic acid, dodecenylsuccinic acid, etc. Carboxylic acid; Examples thereof include trivalent carboxylic acids such as trimellitic acid, pyromellitic acid, naphthalene tricarboxylic acid, naphthalene tetracarboxylic acid, pyrene tricarboxylic acid and pyrene tetracarboxylic acid. These can be used alone or in combination of two or more.

Examples of the polyhydric alcohol monomer include ethylene glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, octanediol, decanediol, dodecanediol, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct. And other dihydric alcohols; trivalent polyols such as glycerin, pentaerythritol, hexamethylol melamine, hexaethylol melamine, tetramethylol benzoguanamine, tetraethylol benzoguanamine and the like. These can be used alone or in combination of two or more.

The ratio of polyvalent carboxylic acid to polyhydric alcohol is such that the equivalent ratio (OH) / (COOH) of the hydroxy group (OH) of the polyhydric alcohol to the carboxy group (COOH) of the polyvalent carboxylic acid is 1.5 / 1. It is preferably in the range of ~ 1 / 1.5, and more preferably in the range of 1.2 / 1-1 / 1.2.

The number average molecular weight (Mn) of the amorphous polyester resin is preferably in the range of 2000 to 10000. The molecular weight of the amorphous polyester resin measured by GPC is the same as that of the vinyl resin described later, except that the amorphous polyester resin is used as the measurement sample.

The glass transition point (T _g ) of the amorphous polyester resin is preferably in the range of 20 to 70 ° C. The glass transition point (T _g ) can be measured in the same manner as in the case of the vinyl resin described later.

The amorphous polyester resin can be a hybrid resin modified with a styrene-acrylic resin.
The amorphous polyester resin, which is a hybrid resin, has high compatibility with the vinyl-based resin in which the styrene-acrylic resin portion is contained in the core, and therefore, it easily aggregates on the surface of the core particles and easily covers the entire surface. Become.

The fact that the amorphous polyester resin is modified with the styrene-acrylic resin means that the segment of the amorphous polyester resin and the segment of the styrene-acrylic resin are chemically bonded. The segment of the amorphous polyester resin refers to a resin portion derived from the amorphous poeryster resin in the hybrid resin, that is, a molecular chain having the same chemical structure as the amorphous polyester resin. The styrene-acrylic resin segment refers to a resin portion derived from the styrene-acrylic resin in the hybrid resin, that is, a molecular chain having the same chemical structure as the styrene-acrylic resin.

The styrene-acrylic resin is a polymer of a styrene-based monomer and a (meth) acrylic acid-based monomer.
As the styrene-based monomer, known ones can be used, and examples thereof include those that can be used as a vinyl-based resin contained in the core particles described later, derivatives thereof, and the like. In addition, one of these can be used alone or in combination of two or more.

Examples of the (meth) acrylic acid-based monomer include those that can be used as a vinyl-based resin contained in the core particles described later, derivatives thereof, and the like. In addition, one of these can be used alone or in combination of two or more.

In addition to the styrene-based monomer and the (meth) acrylic acid-based monomer, other monomers can also be used. Examples of other monomers that can be used include monomers having an ionic dissociation group described later.

The styrene-acrylic resin is obtained by adding any commonly used polymerization initiator such as peroxide, persulfide, and azo compound to the above-mentioned monomer polymerization, and bulk polymerization, solution polymerization, emulsion polymerization, and mini-emulsion. It can be obtained by polymerizing by a known polymerization method such as a method, a suspension polymerization method, or a dispersion polymerization method. A commonly used chain transfer agent such as alkyl mercaptan or mercapto fatty acid ester can be used for the purpose of adjusting the molecular weight at the time of polymerization.

The content of the styrene-acrylic resin segment in the hybrid resin is preferably in the range of 1 to 30% by mass because the plasticity of the toner particles can be easily controlled.

The hybrid resin can be obtained by reacting an amorphous polyester resin prepared individually with a styrene-acrylic resin and chemically bonding them.
From the viewpoint of facilitating the bond, it is preferable to incorporate a substituent capable of reacting with both the amorphous polyester resin and the styrene-acrylic resin into the amorphous polyester resin or the styrene-acrylic resin. For example, when a styrene-acrylic resin is produced, it reacts with a carboxy group (COOH) or a hydroxy group (OH) of an amorphous polyester resin together with a styrene-based monomer and a (meth) acrylic acid-based monomer as raw materials. A compound having a possible substituent and a substituent capable of reacting with the styrene-acrylic resin is added. Thereby, a styrene-acrylic resin having a substituent capable of reacting with a carboxy group (COOH) or a hydroxy group (OH) in the amorphous polyester resin can be obtained.

Further, the hybrid resin either carries out a polymerization reaction to produce a styrene-acrylic resin in the presence of a prepared amorphous polyester resin, or produces an amorphous polyester resin in the presence of a prepared styrene-acrylic resin. It can also be obtained by carrying out a polymerization reaction. In either case, at the time of the polymerization reaction, a compound having a substituent capable of reacting with both the amorphous polyester resin and the styrene-acrylic resin as described above may be added.

It is more preferable that the number average molecular weight (Mn) of the hybrid resin is in the range of 2000 to 10000 from the viewpoint of fixability.

The content of the amorphous polyester resin in the toner particles is preferably in the range of 1 to 50% by mass from the viewpoint of fixability and environmental stability of charging.

《Core particles》
The core particles contain at least a vinyl resin.
The core particles preferably contain a crystalline resin in addition to the vinyl resin. In addition, the core particles may also contain a colorant, a mold release agent, and the like.
In the present invention, the binder resin refers to an amorphous resin contained in the toner matrix particles.
Further, the core particles include amorphous resins other than vinyl resins, colorants, mold release agents, and other materials (resins, organic compounds, etc.) other than crystalline resins as long as the effects of the present invention are not hindered. ) May be included.

[Vinyl resin contained in core particles]
As the vinyl-based resin contained in the core particles, a styrene-based compound, a methacrylic acid ester-based compound, an acrylic acid ester-based product, and a copolymer thereof are preferable. More preferred are styrene-based compounds, methacrylic acid ester-based compounds, and copolymers thereof.
As the monomer of the compound forming the amorphous vinyl resin (hereinafter, also referred to as “vinyl-based monomer”), one kind or two or more kinds selected from the following are used. Can be used.
(1) Styrene-based compound monomers o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert -Butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene and the like and derivatives thereof.
(2) Monomer of (meth) acrylic acid ester-based compound Methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, methacrylic 2-Ethylhexyl acid, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t acrylate -Butyl, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate and the like and derivatives thereof.
(3) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate, etc.
(4) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether, etc.
(5) Vinyl ketones Vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, etc.
(6) N-vinyl compounds N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone and the like.
(7) Others Vinyl compounds such as vinylnaphthalene and vinylpyridine, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylnitrile and acrylamide.

Further, as the vinyl-based monomer, it is preferable to use a monomer having an ionic dissociation group such as a carboxy group, a sulfonic acid group, or a phosphoric acid group. Specific examples include: Acrylic acid, methacrylic acid, maleic acid, itaconic acid, silicic acid, fumaric acid, maleic acid monoalkyl ester, monoalkyl itaconic acid as monomers having a carboxy group. Esters and the like can be mentioned. Examples of the monomer having a sulfonic acid group include styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamide-2-methylpropane sulfonic acid and the like. Further, examples of the monomer having a phosphoric acid group include acid phosphooxyethyl methacrylate.

Further, polyfunctional vinyls may be used as the vinyl-based monomer, and the amorphous vinyl-based resin may have a crosslinked structure. Examples of polyfunctional vinyls include divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, and neopentyl glycol. Diacrylate and the like can be mentioned.

The vinyl-based resin contained in the core particles has been described in detail above. In addition to the vinyl-based resin, the core particles are amorphous as, for example, an amorphous resin within a range that does not hinder the expression of the effects of the present invention. Other resins such as sex polyester resin may be used.

The glass transition point (T _g ) of the vinyl resin is preferably 25 to 60 ° C, more preferably 35 to 55 ° C. When the glass transition point of the vinyl resin is within the above range, sufficient low-temperature fixability and heat-resistant storage property can be obtained at the same time. The glass transition point (T _g ) of the vinyl resin is a value measured using "Diamond DSC" (manufactured by PerkinElmer). As a measurement procedure, 3.0 mg of a measurement sample (vinyl resin) is sealed in an aluminum pan and set in a holder. The reference used was an empty aluminum pan. The measurement conditions were a measurement temperature of 0 to 200 ° C., a temperature rise rate of 10 ° C./min, and a temperature decrease rate of 10 ° C./min, and the temperature was controlled by Heat-cool-Heat. Analysis is performed based on the data in Heat, and an extension of the baseline before the rise of the first endothermic peak and a tangent line indicating the maximum slope between the rising part of the first peak and the peak peak are drawn, and the intersection thereof. Is the glass transition point.

The molecular weight of the vinyl resin as measured by gel permeation chromatography (GPC) is preferably 1000 to 100,000 in terms of weight average molecular weight (Mw). In the present invention, the molecular weight of the vinyl resin by GPC is a value measured as follows. That is, using the apparatus "HLC-8120GPC" (manufactured by Tosoh Co., Ltd.) and the column "TSKguardsample + TSKgelSuperHZ-M3 series" (manufactured by Tosoh Co., Ltd.), while maintaining the column temperature at 40 ° C. Flow at 2 mL / min and treat the measurement sample (vinyl resin) at room temperature for 5 minutes using an ultrasonic disperser. Dissolve in tetrahydrofuran to a concentration of 1 mg / mL under dissolution conditions, and then dissolve in tetrahydrofuran, then pore size 0.2 μm. A sample solution was obtained by treatment with the membrane filter of the above, 10 μL of this sample solution was injected into the apparatus together with the above carrier solvent, and the sample solution was detected using a refractive index detector (RI detector) to determine the molecular weight distribution of the measurement sample. Calculated using a calibration line measured with monodisperse polystyrene standard particles. Ten points are used as polystyrene for calibration curve measurement.

[Crystalline resin]
The core particles preferably contain a crystalline resin. Due to the sharp melt property of the crystalline resin, it is possible to obtain a toner having low temperature fixability while maintaining high heat-resistant storage property.
The crystalline resin is not particularly limited, and conventionally known crystalline resins in the present technical field can be used. Among them, the crystalline resin preferably contains a crystalline polyester, and a core containing a vinyl resin. From the viewpoint of good dispersibility in the particles, it is more preferable that the crystalline resin is formed by bonding the vinyl-based polymerization segment and the polyester polymerization segment.
The "crystalline polyester resin" is a differential scanning of known polyester resins obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a divalent or higher alcohol (polyhydric alcohol). In calorimeter measurement (DSC), it refers to a resin that has a clear heat absorption peak rather than a stepped heat absorption change. A clear endothermic peak specifically means a peak in which the half width of the endothermic peak is within 15 ° C. when measured at a temperature rise rate of 10 ° C./min in differential scanning calorimetry (DSC). To do.

The polyvalent carboxylic acid is a compound containing two or more carboxy groups in one molecule, and an alkyl ester, an acid anhydride and an acid chloride of the polyvalent carboxylic acid compound can be used. Specifically, for example, oxalic acid, succinic acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonandicarboxylic acid, decandicarboxylic acid, undecandicarboxylic acid, dodecandicarboxylic acid, fumaric acid, Citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelli acid, tartrate acid, mucilage acid, phthalic acid, isophthalic acid, Telephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylene diacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o-phenylenediglycolic acid, diphenylacetic acid, Divalent carboxylic acids such as diphenyl-p, p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracendicarboxylic acid, dodecenylsuccinic acid It may be combined with a trivalent or higher carboxylic acid such as trimellitic acid, pyromellitic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid and pyrenetetracarboxylic acid. In the present invention, the aliphatic polyvalent carboxylic acid is preferable as the polyvalent carboxylic acid forming the crystalline polyester resin.

A polyhydric alcohol is a compound containing two or more hydroxy groups in one molecule. Specifically, for example, ethylene glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, octanediol, decanediol, 1,12-dodecanediol, ethylene oxide adduct of bisphenol A, propylene oxide of bisphenol A. Bivalent alcohols such as additives; trihydric or higher polyols such as glycerin, pentaerythritol, hexamethylol melamine, hexaethylol melamine, tetramethylol benzoguanamine, tetraethylol benzoguanamine and the like can be mentioned. In the present invention, the polyhydric alcohol forming the crystalline polyester resin is preferably an aliphatic polyhydric alcohol.

The melting point (Tm) of the crystalline resin is preferably 50 to 95 ° C, more preferably 55 to 85 ° C. When the melting point of the crystalline resin is in the above range, sufficient low temperature fixability and excellent hot offset resistance can be obtained. The melting point of the crystalline resin can be controlled by the resin composition.

In the present invention, the melting point of a crystalline resin such as a crystalline polyester resin is a value measured as follows. That is, in the first heating process of raising the temperature from 0 ° C. to 200 ° C. at a lifting speed of 10 ° C./min using a differential scanning calorimeter "Diamond DSC" (manufactured by PerkinElmer), 200 ° C. at a cooling rate of 10 ° C./min. It is measured by the measurement conditions (heating / cooling conditions) that go through the cooling process of cooling from 0 ° C. to 0 ° C. and the second heating process of raising the temperature from 0 ° C. to 200 ° C. at a lifting speed of 10 ° C./min in this order. Based on the DSC curve obtained by this measurement, the heat absorption peak top temperature derived from the crystalline polyester resin in the first heating process is defined as the melting point (Tm). As a measurement procedure, 3.0 mg of a measurement sample (crystalline polyester resin) is enclosed in an aluminum pan and set in a diamond DSC sample holder. The reference uses an empty aluminum pan.

The molecular weight of the crystalline polyester resin measured by gel permeation chromatography (GPC) is preferably 5000 to 50,000 in terms of weight average molecular weight (Mw) and 1500 to 25,000 in terms of number average molecular weight (Mn). The molecular weight of the crystalline polyester resin measured by GPC is the same as that of the vinyl resin except that the crystalline polyester resin is used as the measurement sample.

The content of the crystalline resin in the toner matrix particles is preferably 3 to 30% by mass. If it is 3% by mass or more, a sufficient effect of low-temperature fixing property can be obtained, and if it is 30% by mass or less, a sufficient heat-resistant storage property can be obtained.

As described above, the crystalline resin preferably contains a crystalline resin in which a vinyl-based polymerization segment and a polyester polymerization segment are bonded (hereinafter, also simply referred to as “hybrid resin”). At this time, the vinyl-based polymerization segment and the polyester polymerization segment are preferably crystalline resins bonded via both reactive monomers. The polyester polymerized segment is a segment composed of a crystalline polyester resin, and is also referred to as a “crystalline polyester polymerized segment” in the following description.

(Vinyl-based polymerization segment)
The vinyl-based polymerization segment constituting the hybrid resin is composed of a resin obtained by polymerizing a vinyl-based monomer. Here, as the vinyl-based monomer, the above-mentioned vinyl-based monomer can be similarly used as the monomer constituting the vinyl-based resin, and thus detailed description thereof will be omitted here. The content of the vinyl-based polymerized segment in the hybrid resin is preferably in the range of 5 to 30% by mass. Within this range, the intensity of the toner image can be increased.

(Crystally polyester polymerized segment)
The crystalline polyester polymerization segment constituting the hybrid resin is composed of a crystalline polyester resin produced by performing a polycondensation reaction of a polyvalent carboxylic acid and a polyhydric alcohol in the presence of a catalyst. Here, since the specific types of the polyvalent carboxylic acid and the polyhydric alcohol are as described above, detailed description thereof will be omitted here.

(Bi-reactive monomer)
As described above, the crystalline resin formed by bonding the vinyl-based polymerization segment and the polyester polymerization segment is preferably bonded by a bireactive monomer.
The "bireactive monomer" is a monomer that binds a crystalline polyester polymerization segment and a vinyl-based polymerization segment. Specifically, for example, a group selected from a hydroxy group, a carboxy group, an epoxy group, a primary amino group and a secondary amino group forming a crystalline polyester polymerization segment and a vinyl-based polymerization segment are included in the molecule. A monomer having both an ethylenically unsaturated group to be formed, preferably a hydroxy group or a monomer having both a carboxy group and an ethylenically unsaturated group is preferable. More preferably, it is a monomer having both a carboxy group and an ethylenically unsaturated group. That is, it is preferably a vinyl-based carboxylic acid.

Specific examples of the bireactive monomer include acrylic acid, methacrylic acid, fumaric acid, maleic acid, and the like, and further, these hydroxyalkyl (1 to 3 carbon atoms) esters. Although it may be used, acrylic acid, methacrylic acid and fumaric acid are preferable from the viewpoint of reactivity. The crystalline polyester polymerization segment and the vinyl-based polymerization segment are bonded via the bireactive monomer. The amount of the bireactive monomer used is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the total amount of the vinyl-based monomer from the viewpoint of improving the low temperature fixability, high temperature offset resistance and durability of the toner. More preferably, 4 to 8 parts by mass.

The amount of both reactive monomers used is 100 parts by mass based on the total amount of the vinyl-based monomer constituting the vinyl-based polymerization segment from the viewpoint of improving the low-temperature fixability, high-temperature offset resistance and durability of the toner. 1 to 10 parts by mass is preferable, and 4 to 8 parts by mass is more preferable.

(Hybrid resin manufacturing method)
As a method for producing the hybrid resin, an existing general scheme can be used. The following three are typical methods.
(1) An aromatic vinyl monomer for pre-polymerizing a crystalline polyester polymerized segment, reacting the polyester polymerized segment with a bireactive monomer, and further forming a vinyl-based polymerized segment, and ( Meta) A method of forming a hybrid resin by reacting an acrylic acid ester-based monomer.
(2) A polyvalent carboxylic acid and a polyhydric alcohol for prepolymerizing a vinyl-based polymerization segment, reacting the vinyl-based polymerization segment with a bireactive monomer, and further forming a crystalline polyester polymerization segment. A method of forming a crystalline polyester polymerized segment by reacting.
(3) A method in which a crystalline polyester polymerization segment and a vinyl-based polymerization segment are each polymerized in advance, and both reactive monomers are reacted with these to bond the two.

In the present invention, any of the above-mentioned production methods can be used, but the method of the above-mentioned item (2) is preferable.
Specifically, a polyvalent carboxylic acid and a polyhydric alcohol forming a crystalline polyester polymerization segment, and a vinyl-based monomer and a bireactive monomer forming a vinyl-based polymerization segment are mixed to obtain a polymerization initiator. In addition, it is preferable that a vinyl-based monomer and a bireactive monomer are addition-polymerized to form a vinyl-based polymerization segment, and then an esterification catalyst is added to carry out a polycondensation reaction.

Here, as the catalyst for synthesizing the crystalline polyester polymerized segment, various conventionally known catalysts can be used. Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin 2-ethylhexanoate (II), titanium compounds such as titanium diisopropyrate bistriethanolamineate, and the like, and examples of the esterification cocatalyst include gallic acid. Acids and the like can be mentioned. The amount of the esterification catalyst used is preferably 0.01 to 1.5 parts by mass, preferably 0.1 parts by mass, based on 100 parts by mass of the total amount of the polyhydric alcohol compound, the polyvalent carboxylic acid compound, and the bireactive monomer component. ~ 1.0 parts by mass is more preferable. The amount of the esterification co-catalyst used is preferably 0.001 to 0.5 parts by mass with respect to 100 parts by mass of the total amount of the polyhydric alcohol compound, the polyvalent carboxylic acid compound and the bireactive monomer component. 01 to 0.1 parts by mass is more preferable.

[Colorant]
As the colorant according to the present invention, carbon black, magnetic material, dye, pigment and the like can be arbitrarily used, and as carbon black, channel black, furnace black, acetylene black, thermal black, lamp black and the like are used. To. As magnetic materials, ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, alloys of a type called Heusler alloys such as manganese-copper-aluminum and manganese-copper-tin, chromium dioxide and the like can be used.

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

Examples of colorants for magenta or red include C.I. I. Pigment Red 2, 3, 5, 6, 6, 7, 15, 16, 48: 1, 53: 1, 57: 1, 60, 63,
64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 139, 144, 149, 150, 163. , 166, 170, 177, 178, 184, 202, 206, 207, 209, 222, 238, 269 and the like.

Further, as a colorant for orange or yellow, C.I. I. Pigment Orange 31, 43, C.I. I. Pigment Yellow 12, 14, 14, 15, 17, 74, 83, 93, 94, 138, 155, 162, 180, 185 and the like.

Further, as a colorant for green or cyan, C.I. I. Pigment Blue 2, 3, 15, 15, 15: 2, 15: 3, 15: 4, 16, 17, 60, 62, 66, C.I. I. Pigment Green 7 and the like.

These colorants may be used alone or in combination of two or more, if necessary.

The amount of the colorant added is preferably in the range of 1 to 30% by mass, more preferably in the range of 2 to 20% by mass with respect to the entire toner, and a mixture thereof can also be used. Within such a range, the color reproducibility of the image can be ensured.

The size of the colorant is, for example, in the range of 10 to 1000 nm, preferably in the range of 50 to 500 nm, and more preferably in the range of 80 to 300 nm in terms of volume average particle size.

[Release agent]
The release agent according to the present invention is not particularly limited, and known ones can be used. Specifically, for example, polyolefin waxes such as polyethylene wax and polypropylene wax, branched hydrocarbon waxes such as microcrystallin wax, long-chain hydrocarbon waxes such as paraffin wax and sazole wax, and distearyl ketones. Dialkylketone wax, carnauba wax, montan wax, behenate behenate, trimethylpropantribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecan Examples thereof include ester waxes such as diol distearate, tristearyl trimellitic acid and distealyl maleate, and amide waxes such as ethylenediamine behenylamide and tristealylamide trimellitic acid.

The melting point of the release agent is preferably 40 to 160 ° C, more preferably 50 to 120 ° C. By keeping the melting point within the above range, the heat-resistant storage property of the toner is ensured, and stable toner image formation can be performed without causing cold offset or the like even when fixing is performed at a low temperature. The content of the release agent in the toner is preferably 1 to 30% by mass, more preferably 5 to 20% by mass.

[Other ingredients]
In addition to the above components, the toner matrix particles of the present invention may contain an internal additive such as a charge control agent, if necessary.

<Charge control agent>
As the charge control agent, various known compounds such as niglosin dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, and salicylate metal salts can be used. ..

The amount of the charge control agent added is usually 0.1 to 10% by mass, preferably 0.5 to 5% by mass, based on 100% by mass of the binder resin in the finally obtained toner matrix particles. Toner.

The size of the charge control agent particles is, for example, 10 to 1000 nm, preferably 50 to 500 nm, and more preferably 80 to 300 nm in terms of number average primary particle diameter.

《External agent》
The toner of the present invention contains crosslinked vinyl resin particles as an external additive.

[Crosslinked vinyl resin particles]
The crosslinked vinyl resin particles according to the present invention have an average number diameter of 30 to 300 nm.

The crosslinked vinyl-based resin particles according to the present invention are not particularly limited, but specifically, particles composed of a crosslinked resin containing a structural unit derived from a crosslinkable vinyl monomer are preferable.

The crosslinked vinyl-based resin particles according to the present invention are preferably particles composed of a resin containing a structural unit derived from a radically polymerizable crosslinkable vinyl monomer, and the crosslinked form thereof is, for example, a plurality of radicals. Of the polymerizable unsaturated groups, the cross-linking may be performed by a radically polymerizable unsaturated group that was not involved in the polymerization, or by another reactive functional group, and is not particularly limited. The crosslinkable vinyl monomer is not particularly limited, and among them, the crosslinkable vinyl monomer having a plurality of radically polymerizable unsaturated groups includes, for example, divinylbenzene, 1,4-divinyloxybutane, and divinylsulfone. Vinyl compounds such as diallyl phthalate and isomers thereof, triallyl isocyanurate and derivatives thereof, allyl compounds such as triallyl trimetate; ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate and the like (poly). ) Ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate and other (poly) oxyalkylene glycol di (meth) acrylate; pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, penta Elythritol di (meth) acrylate, trimethylolpropantri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, 1, Examples thereof include (meth) acrylic compounds such as 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tetramethylol methanetri (meth) acrylate, and tetramethylol propanetetra (meth) acrylate. In addition, "(meth) acrylate" means "acrylate" or "methacrylate".

Similarly, among the crosslinkable vinyl monomers, the crosslinkable vinyl monomer having a reactive functional group other than the radically polymerizable unsaturated group includes, for example, an epoxy group and an amino as the reactive functional group. Examples thereof include a radically polymerizable vinyl monomer having a group, a carboxy group, a hydroxy group, a thiohydroxy group (-SH group) and the like, and specifically, hydroxyethyl (meth) acrylate and dimethylaminoethyl (meth). Preferred examples thereof include acrylate, glycidyl (meth) acrylate, (meth) acrylic acid, and (meth) acrylamide. These crosslinkable vinyl monomers may be used alone or in combination of two or more.

Among the crosslinkable vinyl monomers, those that can be preferably used as a crosslinking agent are divinylbenzene, divinyltoluene, ethylene glycol di (meth) acrylate, ethylene oxide di (meth) acrylate, and tetraethylene oxide di (meth) acrylate. , 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane triacrylate, tetramethylolpropane tetra (meth) acrylate and other ethylenically unsaturated group-containing monomers. Can be mentioned. These ethylenically unsaturated group-containing monomers may be used alone or in combination of two or more.
Further, particularly preferable is divinylbenzene.
The content of the cross-linking agent is preferably 0.5 to 100 parts with respect to 100 parts of the vinyl resin particles. More preferably, it is 5 to 50 parts.
When the number of copies is 0.5 or more, the strength is good and the spacer effect over a long period of printing can be sufficiently obtained. Further, when the number of parts is 100 or less, it is easy to control the particle size to a desired value.

The content of the structural unit derived from the crosslinkable vinyl monomer in the crosslinked vinyl resin particles according to the present invention is not particularly limited, but is 0.5 with respect to 100% by mass of the non-crosslinkable vinyl monomer. It is preferably ~ 100% by mass, more preferably 3 to 50% by mass, and even more preferably 5 to 30% by mass. When this content is 0.5% by mass or more, the strength becomes high and the spacer effect for a long period of time can be obtained. On the other hand, if this content is 100% by mass or less, there is an advantage that the desired particle size can be easily controlled.

In the crosslinked vinyl resin particles according to the present invention, in addition to the structural unit derived from the crosslinkable vinyl monomer, the structural unit derived from the non-crosslinkable vinyl monomer capable of radical polymerization and other radically polymerizable units. It may contain structural units derived from the polymer.

The non-crosslinkable vinyl monomer is not particularly limited, and is, for example, styrene, p- (m-) methyl styrene, p- (m-) ethyl styrene, p- (m-) chloro styrene, p- (m). -) Styrene-based monomers such as chloromethylstyrene, styrene sulfonic acid, p- (m-) t-butoxystyrene, α-methyl-pt-amyloxystyrene, pt-amyloxystyrene; (meth) acrylic Methyl acid acid, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (Meta) acrylates such as (meth) acrylate, hydroxyethyl (meth) acrylate, diethylene glycol mono (meth) acrylate, glycerol mono (meth) acrylate, styrene glycol mono (meth) acrylate, butanediol mono (meth) acrylate, etc. Monomer; unsaturated styrene-based monomer such as (meth) acrylic acid and maleic acid; alkyl vinyl ether such as methyl vinyl ether and ethyl vinyl ether; vinyl ester-based monomer such as vinyl acetate and vinyl butyrate; (meth) acrylonitrile, N-methyl ( Examples thereof include meta) acrylamide, N-ethyl (meth) acrylamide; and the like. These may be used alone or in combination of two or more.

The other radically polymerizable monomer is not particularly limited, but for example, monomers having a hydroxy group such as hydroxyethyl (meth) acrylate; having a polyethylene glycol component such as methoxypolyethylene glycol (meth) acrylate. Monoterms; and the like. These may be used alone or in combination of two or more. In addition, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, pentanfluoropropyl (meth) acrylate, octafluoroamyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, perfluorobutylethyl (meth). Fluorine atom-containing (meth) acrylates such as acrylate; and the like can also be mentioned. These may be used alone or in combination of two or more.

In the crosslinked vinyl resin particles according to the present invention, the structural unit derived from the non-crosslinkable vinyl monomer and the structural unit derived from the other radically polymerizable monomer contain the structural unit derived from the crosslinkable vinyl monomer. It suffices if it is included outside the range of the ratio.

As described above, the average particle size of the number of crosslinked vinyl resin particles according to the present invention is essential to be 30 to 300 nm, preferably 50 to 200 nm. When the average particle size is lower than 30 nm, the spacer effect becomes small and the transferability after long-term use deteriorates.
On the other hand, if it is larger than 300 nm, the amount of desorption from the toner increases, and the effect is not exhibited.
The average particle size is determined in the toner bottle, for example, by using a scanning electron microscope (SEM) to magnify the toner by a factor of 30,000 (the organic fine particles may be crushed in the toner in the developer). The SEM photograph of the toner) is captured by a scanner, and the crosslinked vinyl-based resin particles of the SEM photographic image are binarized by an image processing analyzer, and a horizontal ferret of 100 crosslinked vinyl-based resin particles is performed. The diameter may be calculated and the average value (number average particle diameter) may be used as the average particle diameter. At this time, it is necessary to distinguish it from the inorganic particles by EDS.

The crosslinked vinyl resin particles that can be used in the present invention can be produced by a known polymerization method, and when produced using the above crosslinkable vinyl monomer, for example, a known suspension polymerization method. A typical production method uses a radical polymerization reaction such as an emulsion polymerization method or an emulsion polymerization method. In the present invention, an emulsion polymerization method capable of producing particles having a particle size of about 100 nm is preferable from the viewpoint of particle size.
That is, in the emulsion polymerization method, organic particles having a desired size can be produced by controlling the following reaction factors, which is preferable.
As a specific method for controlling the number average particle size of organic particles,
Examples include (1) controlling the concentration of the surfactant in the aqueous medium, (2) controlling the amount of the polymerization initiator used, and (3) controlling the polymerization temperature, which are desired by appropriately combining these conditions. It is possible to produce crosslinked vinyl-based resin particles having an average particle size of.

Further, with respect to the crosslinked vinyl resin particles, the amount of the precipitate formed when vacuum dried, which is measured by the following measuring method, is preferably 20% by mass or less, preferably 5% by mass or less, based on the total amount. Is even more preferable.

(Method of measuring the amount of precipitate)
Approximately 0.3 g of dried crosslinked vinyl resin particles are weighed as a sample, put into 30 g of tetrahydrofuran, and stirred for 60 minutes. Next, a centrifuge "H-900" (manufactured by Kokusan Co., Ltd.) is used for centrifugation at 20000 rpm for 5 minutes. Then, the precipitate is dried in a vacuum dryer and then its mass is measured.

The method for producing crosslinked vinyl resin particles according to the present invention includes, for example, a step of radically polymerizing a radically polymerizable monomer containing a crosslinkable vinyl monomer.

The crosslinked vinyl-based resin particles are particles obtained by radically polymerizing a radically polymerizable monomer containing a crosslinkable vinyl monomer. Further, the crosslinked resin particles can be obtained by using the crosslinkable vinyl monomer, but the crosslinked form thereof is not particularly limited, and the desired crosslinked form depends on the type of the crosslinkable vinyl monomer used. Can be. For example, cross-linking by a radically polymerizable unsaturated group among a plurality of radically polymerizable unsaturated groups, cross-linking by dehydration condensation of a hydroxy group, cross-linking by a reaction between an epoxy group and an amino group, and the like. Examples thereof include cross-linking with a functional group having the reactivity of the above.

The method for producing the crosslinked vinyl resin particles is not particularly limited, and examples thereof include an emulsion polymerization method (including soap-free). Specifically, in the emulsion polymerization method, a medium such as water, a monomer sparingly soluble in the medium, and an emulsifier (surfactant) are mixed, and a polymerization initiator (usually a radical generator) that can be dissolved in the medium is mixed therein. ) Is added to this polymerization method.

Here, as the polymerization initiator used in the present invention, persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate are preferable from the viewpoint of charging. One type of polymerization initiator may be used alone, or two or more types may be used in combination. The amount of the polymerization initiator used is not particularly limited, but is preferably 0.1 to 5% by mass, and more preferably 0.3 to 3% by mass, based on 100% by mass of the vinyl-based monomer. Is.

The surfactant is not particularly limited, and examples of suitable surfactants include the following ionic surfactants.

Examples of the ionic surfactant include sodium dodecylbenzene sulfonate, sodium arylalkyl polyether sulfonate, and sodium 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol-6-sulfonate. , O-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sodium sulfonate and other sulfonates, lauryl Sulfate esters such as sodium sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, fatty acids such as sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, etc. Examples include salt.

In addition, a nonionic surfactant can also be used. For example, polyethylene oxide, polypropylene oxide, combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, sorbitan ester. And so on. If the particle size of the crosslinked vinyl resin particles is relatively small, the amount of the residual surfactant is relatively large, so that a dialysis treatment is often required.

The amount of the crosslinked vinyl resin particles added is not particularly limited, but it is preferably contained in the range of 0.05 to 3.0% by mass, more preferably, with respect to the entire toner for electrostatic latent image development. , 0.1 to 1.5% by mass. When it is 0.05% by mass or more, the spacer effect can be sufficiently exhibited, while when it is 3.0% by mass or less, white spot image defects after long-term use can be prevented, which is preferable.

[Other external additives]
From the viewpoint of controlling the fluidity and chargeability of the toner particles, the toner of the present invention has an external additive other than the crosslinked vinyl resin particles (hereinafter, other external additives other than the crosslinked vinyl resin particles). It is preferable that the agent further contains (also referred to simply as "other external additive"). Examples of such external additives include silica particles, titania particles, alumina particles, zirconia particles, zinc oxide particles, chromium oxide particles, cerium oxide particles, antimony oxide particles, tungsten oxide particles, tin oxide particles, and tellurium oxide particles. , Manganese oxide particles and boron oxide particles.
The number average primary particle size of such external additive particles can be adjusted by, for example, classification or mixing of classified products.
It is preferable that the surface of the external additive particles is hydrophobized. A known surface modifier is used for the hydrophobization treatment. The surface modifier includes a silane coupling agent, a titanate-based coupling agent, an aluminate-based coupling agent, a fatty acid, a fatty acid metal salt, an esterified product thereof, rosin acid, silicon oil, and the like.

The amount of other external additives added to the toner is not particularly limited, but is preferably 0.1 to 10.0% by mass, more preferably 1.0 to 3% by mass, based on 100% by mass of the toner. It is 0.0% by mass.

(Toner glass transition point)
The glass transition point (T _g ) of the toner according to the present invention is preferably 25 to 65 ° C, more preferably 35 to 55 ° C. When the glass transition point of the toner of the present invention is in the range of 25 to 65 ° C., sufficient low-temperature fixability and heat-resistant storage property can be obtained at the same time. The glass transition point of the toner is measured in the same manner as in the case of the vinyl resin except that the toner is used as the measurement sample.

(Diameter of toner particles)
The particle size of the toner (matrix) particles according to the present invention is, for example, preferably 3 to 8 μm, more preferably 5 to 8 μm in terms of volume-based median diameter (hereinafter, also referred to as “D50% diameter”). .. The D50% diameter can be controlled by the concentration of the flocculant used at the time of production, the amount of the organic solvent added, the fusion time, the composition of the binder resin, and the like. Since the volume-based median diameter is in the range of 5 to 8 μm, it is possible to faithfully reproduce a very minute dot image of 1200 dpi level. The median diameter based on the volume of toner particles is measured and calculated using a measuring device that connects a computer system equipped with data processing software "Software V3.51" to "Multisizer 3" (manufactured by Beckman Coulter). It is a thing. Specifically, 0.02 g of the measurement sample (toner) is diluted 10 times with pure water in 20 mL of a surfactant solution (for the purpose of dispersing toner particles, for example, a neutral detergent containing a surfactant component). After adding to the solution) and acclimatizing, ultrasonic dispersion was performed for 1 minute to prepare a toner dispersion, and this toner dispersion contained "ISOTON II" (manufactured by Beckman Coulter) in the sample stand. Inject into the beaker with a pipette until the indicated concentration of the measuring device reaches 8%. Here, by setting this concentration range, a reproducible measured value can be obtained. Then, in the measuring device, the number of measured particles is 25,000, the aperture diameter is 100 μm, and the frequency value is calculated by dividing the measurement range of 2 to 60 μm into 256, and the volume integration fraction is 50 from the largest. The particle size of% is defined as the volume-based median diameter (D50% diameter).

(Average circularity of toner)
In the toner according to the present invention, the average circularity of each of the toner particles constituting the toner is preferably 0.930 to 1.000 from the viewpoint of stability of charging characteristics and low temperature fixability, and is 0. It is more preferably .950 to 0.995. When the average circularity is in the range of 0.930 to 1.000, individual toner particles are less likely to be crushed, contamination of the triboelectric charging member is suppressed, and the chargeability of the toner is stabilized and formed. The image quality is high in the image. The average circularity of the toner is a value measured using "FPIA-2100" (manufactured by Sysmex Corporation). Specifically, the measurement sample (toner) is blended with an aqueous solution containing a surfactant, ultrasonically dispersed for 1 minute to disperse the particles, and then measured under the measurement conditions HPF by "FPIA-2100" (manufactured by Sysmex). In the (high magnification imaging) mode, shooting is performed at an appropriate density of 3000 to 10000 HPF detections, the circularity of each toner particle is calculated according to the following formula, the circularity of each toner particle is added, and all toner is added. It is a value calculated by dividing by the number of particles. Reproducibility can be obtained when the number of HPFs detected is in the range of 3000 to 10000.
Circularity = (perimeter of a circle having the same projected area as the particle image) / (perimeter of the projected particle image)

≪Toner manufacturing method≫
As a method for producing the toner for electrostatic latent image development of the present invention, a known method can be used.
Examples thereof include a wet production method produced in an aqueous medium, such as an emulsification and agglutination method.
Further, in the method for producing the toner for electrostatic latent image development, the method for producing the toner matrix particles specifically includes, for example, a production method having steps I to VI, but is limited to the following production methods. It's not something.

(Step I) A step of adding a coagulant under stirring to a dispersion mixed solution containing at least a vinyl resin and a release agent (Step II) At least the vinyl resin and the release agent are added under heating and stirring. Step of agglomerating and coalescing to obtain a dispersion of core particles (step III): Step of cooling the dispersion of core particles obtained in step II (step IV): The step of cooling in step III. While raising the temperature of the dispersion liquid of the core particles, the dispersion liquid of the amorphous polyester resin (resin for shell) particles is added, and the particles of the amorphous polyester resin are adhered as shell particles to the surface of the core particles to form the core. -Step of obtaining shell particle dispersion (step V) The core-shell particle dispersion is further heated to fuse the core particles, the shell particles, and the shell particles with each other, and the core-shell type toner matrix particles are fused. Step of obtaining dispersion (step VI): After cooling the core-shell type toner matrix particle dispersion obtained in step V, the core-shell toner matrix particles are used from the core-shell toner matrix particle dispersion. Separation and drying process

In the above step IV, it is preferable to adjust the temperature of the dispersion liquid of the core particles to a temperature at which the core particles, the shell particles, and the shell particles do not fuse with each other.

When a crystalline resin is contained in the core particles, the above step II may be referred to as the following step II'.

(Step II'): The dispersion liquid of the crystalline polyester resin is added to the dispersion mixture to which the flocculant is added in the step I, and at least a vinyl resin, a mold release agent and a crystalline polyester resin are added under heating and stirring. It is preferable that the step is to agglomerate and coalesce with and to obtain a dispersion of core particles.

In the method for producing the toner matrix particles, the flocculant is not particularly limited, but one selected from metal salts is preferably used. For example, a salt of a monovalent metal such as a salt of an alkali metal such as sodium, potassium and lithium, a salt of a divalent metal such as calcium, magnesium, manganese and copper, and a trivalent metal such as iron and aluminum. There is salt etc. Specific examples of the salt include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate and the like, and among these, a divalent metal is particularly preferable. It is salt. The use of divalent metal salts can promote aggregation in smaller amounts. These flocculants can be used alone or in combination of two or more.

Further, the core-shell type toner base particles according to the present invention become toner particles, and eventually toner, by adding an external additive. The toner of the present invention can be produced by adding and mixing an external additive to the surface of the dried core-shell type toner matrix particles.

《Developer》
For example, the toner of the present invention may contain a magnetic substance and be used as a one-component magnetic toner, may be mixed with so-called carrier particles and used as a two-component developer, or a non-magnetic toner may be used alone. Any of these can be preferably used. Since the toner of the present invention has a shell that covers the surface of the core particles within a coverage range of 60 to 99%, it is possible to suitably suppress the desorption of the crosslinked vinyl resin particles from the toner. .. Therefore, even a two-component developer that causes strong stress with carrier particles can be suitably used.
The two-component developer can be produced, for example, by appropriately mixing the toner particles and the following carrier particles so that the content (toner concentration) of the toner particles is 4.0 to 8.0% by mass. it can.
Specific examples of the mixing device used for the mixing include a Nauter mixer, a W cone, and a V-type mixer.

(Carrier particles)
The carrier particles that make up the two-component developer are made of a magnetic material. Examples of the carrier particles include a coated carrier particle having a core material particle made of the magnetic material and a layer of a coating material covering the surface thereof, and a resin dispersion in which fine powder of the magnetic material is dispersed in a resin. Mold carrier particles, are included. The carrier particles are preferably coated carrier particles from the viewpoint of suppressing adhesion of the carrier particles to the photoconductor.

(Core particle)
The core particles are composed of a magnetic material, for example, a substance that is strongly magnetized in that direction by a magnetic field. The magnetic material may be one kind or more, and examples thereof include metals exhibiting ferromagnetism such as iron, nickel and cobalt, alloys or compounds containing these metals and alloys exhibiting ferromagnetism by heat treatment. Is included.
Examples of the metal exhibiting ferromagnetism or a compound containing the same include iron, ferrite represented by the following formula (a) and magnetite represented by the following formula (b). M in the formulas (a) and (b) represents one or more monovalent or divalent metals selected from the group of Mn, Fe, Ni, Co, Cu, Mg, Zn, Cd and Li.
Equation (a): MO · Fe ₂ O ₃
Equation (b): MFe ₂ O ₄
Examples of alloys that exhibit ferromagnetism by the above heat treatment include Heusler alloys such as manganese-copper-aluminum and manganese-copper-tin, and chromium dioxide.
The core material particles are preferably various types of ferrite. This is because the specific gravity of the coated carrier particles is smaller than the specific gravity of the metal constituting the core material particles, so that the impact force of stirring in the developing device can be made smaller.

(Coating material)
The covering material may be one kind or more. As the coating material, a known resin used for coating the core material particles of the carrier particles can be used. The coating material is preferably a resin having a cycloalkyl group from the viewpoint of reducing the water adsorption property of the carrier particles and improving the adhesion of the coating layer to the core material particles. Examples of the cycloalkyl group include a cyclohexyl group, a cyclopentyl group, a cyclopropyl group, a cyclobutyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group and a cyclodecyl group. Of these, a cyclohexyl group or a cyclopentyl group is preferable, and a cyclohexyl group is more preferable from the viewpoint of adhesion between the coating layer and the ferrite particles. The weight average molecular weight Mw of the resin is, for example, 1000 to 800,000, more preferably 100,000 to 750000. The content of the cycloalkyl group in the resin is, for example, 10 to 90% by mass. The content of the cycloalkyl group in the resin can be determined by, for example, thermal decomposition-gas chromatography / mass spectrometry (P-GC / MS), ¹ H-NMR, or the like.

<< Fixing method >>
As a suitable fixing method using the toner of the present invention, a so-called contact heating method can be mentioned. Examples of the contact heating method include a heat pressure fixing method, a heat roll fixing method, and a pressure contact heating fixing method in which the contact heating body is fixed by a rotating pressure member containing a fixedly arranged heating body.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above aspects, and various modifications can be made.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, the indication of "parts" or "%" is used, but unless otherwise specified, it indicates "parts by mass" or "% by mass".

[Preparation of crosslinked vinyl resin particles 1 to 13]
<Preparation of crosslinked vinyl resin particles 1>
A glass reactor equipped with a thermometer, a reflux condenser, a nitrogen gas introduction pipe, and a stirrer is charged with 200 parts of deionized water and 3 parts of sodium lauryl sulfate, and heated to 80 to 85 ° C while aerating nitrogen gas. , 1 part of ammonium persulfate is added under stirring, and a monomer mixture consisting of 40 parts of methyl methacrylate and 40 parts of styrene which are non-crosslinkable monomers and 20 parts of divinylbenzene which is a crosslinkable vinyl monomer. Was added dropwise over 1 hour, and then stirring was continued for 1 hour. The emulsion thus obtained was dried by spray drying to obtain particles having a number average particle size of 100 nm.

(Preparation of crosslinked vinyl resin particles 2 to 13)
The types of the non-crosslinkable monomer and the crosslinkable monomer were changed as shown in Table 1, and the amount of sodium lauryl sulfate was adjusted so that the average particle size of the obtained particles became the value shown in Table 1. Crosslinked vinyl resin particles 2 to 13 were prepared in the same manner as in the preparation of the crosslinked vinyl resin particles 1 except that the particles were adjusted.
In Table 1, St represents styrene and MMA represents methyl methacrylate.

(Measuring method of number average particle size of crosslinked vinyl resin particles)
Using a scanning electron microscope (SEM) "JEM-7401F" (manufactured by JEOL Ltd.), a toner magnified 30,000 times (a developer-style toner may have crushed organic fine particles, so the toner The SEM photograph of the toner in the bottle) is captured by a scanner, and the crosslinked vinyl-based resin particles of the SEM photographic image are binarized by the image processing analyzer "LUZEX AP" (manufactured by JEOL Ltd.) to obtain the crosslinked vinyl. The horizontal ferret diameter of 100 based resin particles was calculated, and the average value was taken as the number average particle diameter.

[Preparation of binder resin particles 1 to 3]
(Preparation of binder resin particle dispersion liquid 1: binder resin particles for core particles)
(1) First-stage polymerization In a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen introduction device, 8 parts by mass of sodium dodecyl sulfate and 3000 parts by mass of ion-exchanged water were charged and stirred at 230 rpm under a nitrogen stream. The internal temperature was raised to 80 ° C. while stirring at a rate. After raising the temperature, 10 parts by mass of potassium persulfate dissolved in 200 parts by mass of ion-exchanged water was added, the liquid temperature was adjusted to 80 ° C. again, and a monomer mixed solution having the following composition was added dropwise over 1 hour. Polymerization was carried out by heating and stirring at 80 ° C. for 2 hours to prepare a dispersion liquid (A) of resin fine particles.
480 parts by mass of styrene n-butyl acrylate 250 parts by mass of methacrylic acid 68 parts by mass of methacrylic acid

(2) Second-stage polymerization In a 5 L reaction vessel equipped with a stirrer, temperature sensor, cooling tube and nitrogen introduction device, 7 parts by mass of polyoxyethylene (2) dodecyl ether sodium sulfate was dissolved in 3000 parts by mass of ion-exchanged water. The solution was prepared and heated to 98 ° C., and then 80 parts by mass (solid content equivalent) of the dispersion liquid (A) of the resin fine particles and a monomer having the following composition and a mold release agent were dissolved at 90 ° C. And was added and mixed and dispersed for 1 hour with a mechanical disperser "CLEARMIX" (manufactured by M-Technique Co., Ltd.) having a circulation path to prepare a dispersion liquid containing emulsified particles (oil droplets).
285 parts by mass styrene n-butyl acrylate 95 parts by mass methacrylic acid 20 parts by mass n-octyl-3-mercaptopropionate 8 parts by mass Release agent: behenate behenate (melting point 73 ° C.) 190 parts by mass Then, in this dispersion , An initiator solution prepared by dissolving 6 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water was added, and this system was heated and stirred at 84 ° C. for 1 hour to carry out polymerization, and a dispersion of resin fine particles (a dispersion liquid of resin fine particles ( B) was prepared.

(3) Third-stage polymerization Further, 400 parts by mass of ion-exchanged water was added to the dispersion liquid (B) of the resin fine particles and mixed well, and then 11 parts by mass of potassium persulfate was dissolved in 400 parts by mass of ion-exchanged water. The solution was added, and under a temperature condition of 82 ° C., a monomer mixed solution having the following composition was added dropwise over 1 hour. After completion of the dropping, polymerization was carried out by heating and stirring for 2 hours, and then the mixture was cooled to 28 ° C. to provide a binder resin particle dispersion 1 made of a vinyl resin styrene-acrylic resin (binding resin particles 1). Prepared.
Styrene 437 parts by mass n-butyl acrylate 17 parts by mass n-octyl acrylate 143 parts by mass Acrylic acid 52 parts by mass n-octyl-3-mercaptopropionate 8 parts by mass

(Preparation of binder resin particle dispersion liquid 2: binder resin particles for shell)
In a four-necked flask with a capacity of 10 liters equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, 500 parts of bisphenol A propylene oxide 2 mol addition, 117 parts of terephthalic acid, 83 parts of fumaric acid and an esterification catalyst ( Two parts of tin octylate) were added and subjected to a polycondensation reaction at 230 ° C. for 8 hours, further reacted at 2 kPa for 2 hours, and cooled to 160 ° C. to obtain a binder resin 2 made of a polyester resin.
The obtained binder resin 2 is dissolved in 100 parts by mass and 400 parts by mass of ethyl acetate (manufactured by Kanto Chemical Co., Ltd.), mixed with 638 parts by mass of a 0.26% by mass concentration sodium lauryl sulfate solution prepared in advance, and stirred. While ultrasonically dispersing with V-LEVEL 300 μA for 30 minutes with an ultrasonic homogenizer “US-150T” (manufactured by Nippon Seiki Seisakusho), the diaphragm vacuum pump “V-700” (BUCHI) was heated to 40 ° C. The ethyl acetate was completely removed while stirring under reduced pressure for 3 hours to obtain a dispersion of the binder resin particles 2 having a solid content of 13.5% by mass (the binder resin particle dispersion 2). Prepared. At this time, the particles contained in the binder resin particle dispersion liquid 2 had a volume-based median diameter of 160 nm.

(Preparation of binder resin particle dispersion liquid 3: binder resin particles for shell)
In a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen introduction device, 8 parts by mass of sodium dodecyl sulfate and 3000 parts by mass of ion-exchanged water were charged, and the inside was stirred at a stirring speed of 230 rpm under a nitrogen stream. The temperature was raised to 80 ° C. After raising the temperature, 10 parts by mass of potassium persulfate dissolved in 200 parts by mass of ion-exchanged water was added, the liquid temperature was adjusted to 80 ° C. again, and a monomer mixed solution having the following composition was added dropwise over 1 hour. Polymerization was carried out by heating and stirring at 80 ° C. for 2 hours to prepare a binder resin particle dispersion liquid 3 containing the binder resin particles 3.
520 parts by mass of styrene n-butyl acrylate 184 parts by mass of methacrylic acid 96 parts by mass of methacrylic acid

Table 2 summarizes the resin types contained in the binder resin particles 1 to 3.
BA represents n-butyl acrylate.

[Preparation of Crystalline Resin Particle Dispersion Liquids 1 and 2]
(Preparation of Crystalline Resin Particle Dispersion Liquid 1 Made of Crystalline Polyester Resin)
220 parts of sebacic acid (molecular weight 202.25) as a polyvalent carboxylic acid compound and 298 parts of 1,12-dodecanediol (molecular weight 202.33) as a polyhydric alcohol compound were added to a nitrogen introduction tube, a dehydration tube, a stirrer and a stirrer. It was placed in a reaction vessel equipped with a thermocouple and heated to 160 ° C. to dissolve it. 2.5 parts of tin 2-ethylhexanoate (II) and 0.2 parts of gallic acid were added, the temperature was raised to 210 ° C., and the reaction was carried out for 8 hours. Further, the reaction was carried out at 8.3 kPa for 1 hour to obtain a crystalline resin 1 made of a polyester resin.
For the obtained crystalline resin 1, a DSC curve was obtained under the condition of a heating rate of 10 ° C./min using a differential scanning calorimeter "Diamond DSC" (manufactured by PerkinElmer Japan Co., Ltd.), and the heat absorption peak top temperature was measured. When the melting point (Tm) was measured by the above method, it was 82.8 ° C. Moreover, when the molecular weight was measured by GPC "HLC-8120GPC" (manufactured by Tosoh Corporation), Mw in terms of standard styrene was 28,000.
A crystalline resin particle dispersion 1 containing the crystalline resin particles 1 was prepared in the same manner as the preparation of the binder resin particle 2 except that the crystalline resin 1 was used instead of the binder resin 2. did.

(Preparation of Crystalline Resin Particle Dispersion Liquid 2 Consisting of Hybrid Resin)
220 parts of sebacic acid (molecular weight 202.25) as a polyvalent carboxylic acid compound of the material of the polyester polymerized segment and 298 parts of 1,12-dodecanediol (molecular weight 202.33) as a polyhydric alcohol compound were added to a nitrogen introduction tube. It was placed in a reaction vessel equipped with a dehydration tube, a stirrer and a thermocouple and heated to 160 ° C. to dissolve it. On the other hand, a solution of 46 parts of styrene, 12 parts of n-butyl acrylate, 4 parts of dicumyl peroxide, and 3 parts of acrylic acid as a bireactive monomer, which are materials for the vinyl-based polymerized segment mixed in advance, is added by a dropping funnel. It was added dropwise over 1 hour. Stirring was continued for 1 hour while maintaining the temperature at 170 ° C. to polymerize styrene, n-butyl acrylate and acrylic acid, and then 2.5 parts of tin (II) 2-ethylhexanoate and 0.2 part of gallic acid were added. The temperature was raised to 210 ° C., and the reaction was carried out for 8 hours. Further, the reaction was carried out at 8.3 kPa for 1 hour to obtain a crystalline resin 2 made of a hybrid resin.
A crystalline resin particle dispersion 2 containing the crystalline resin particles 2 was prepared in the same manner as the preparation of the binder resin particle 2 except that the crystalline resin 2 was used instead of the binder resin 2. did.

The resin types contained in the crystalline resin particles 1 and 2 are summarized in Table 3.

[Preparation of colorant particle dispersion [Bk]]
90 parts by mass of sodium dodecyl sulfate was stirred and dissolved in 1600 parts by mass of ion-exchanged water, and while stirring this solution, 420 parts by mass of carbon black "Legal 330R" (manufactured by Cabot) was gradually added, and then the stirring device " A colorant particle dispersion solution [Bk] in which the colorant particles were dispersed was prepared by performing a dispersion treatment using "Clairemix" (manufactured by M-Technique Co., Ltd.). The volume-based median diameter of the colorant particles in the colorant particle dispersion [Bk] was measured using an electrophoretic light scattering photometer "ELS-800" (manufactured by Otsuka Electronics Co., Ltd.) and found to be 120 nm.

[Manufacturing of toner]
(Manufacturing method of toner 1)
200 parts by mass of binder resin particle dispersion liquid 1, colorant particle dispersion liquid [Bk] 20 parts by mass (solid content conversion) and ion exchange in a reaction vessel equipped with a stirrer, temperature sensor and cooling tube. 2000 parts by mass of water was added, and then a 5 mol / L sodium hydroxide aqueous solution was further added to the reaction vessel to adjust the pH of the mixed solution in the reaction vessel to 10.
Next, an aqueous solution prepared by dissolving 60 parts by mass of magnesium chloride in 60 parts by mass of ion-exchanged water was added to the mixture over 10 minutes at 25 ° C. with stirring (step I).
Next, the temperature of the obtained mixed solution was raised to 78 ° C. over 90 minutes, the number of stirrings was appropriately adjusted, and the particle size of the associated particles was measured with "Colter Multisizer 3" (manufactured by Beckman Coulter). The particles were agglomerated to obtain a core particle dispersion liquid until the median diameter based on the volume of the associated particles was 5.5 μm (step II).
The obtained dispersion was cooled to 45 ° C. (step III), 5 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 8 at 25 ° C., and then the temperature was raised to 63 ° C. to adjust to pH 2. Bending resin particle dispersion liquid 2 (resin dispersion liquid for shell) was added over 20 minutes to agglomerate shell particles on the surface of core particles, and an aqueous solution prepared by dissolving 190 parts by mass of sodium chloride in 760 parts by mass of ion-exchanged water was added thereto. The particles were added to stop the growth (aggregation) of the particles (step IV). Next, the temperature of the obtained dispersion was raised and the particles were fused at 74 ° C. for 50 minutes (shelling time) (step V), and then the dispersion was brought to 35 ° C. After cooling, the fusion of the particles was stopped.
Next, the operation of solid-liquid separation, redispersion of the dehydrated toner cake in ion-exchanged water, and solid-liquid separation was repeated three times for washing, and then dried at 40 ° C. for 24 hours to obtain toner matrix particles 1. (Process VI).
1 part of hydrophobic silica (volume-based median diameter = 12 nm), 0.3 part of hydrophobic titania (volume-based median diameter = 20 nm), and 1 part of vinyl resin particles 1 are added to 100 parts of the toner base particles 1. (That is, 0.01% by mass with respect to the total toner), mixed with a "Henshell mixer" (manufactured by Nippon Coke Industries Co., Ltd.) at a peripheral speed of 35 m / sec at 35 ° C. for 20 minutes, and then 45 μm. Toner 1 was produced by subjecting an external additive treatment for removing coarse particles using a sieve having an opening.

(Manufacturing method of toners 2-4, 7-19, 21-27)
The toner 2 is the same as the toner 1, except that the binder resin particle type for the shell, the shell formation time, the crystalline resin particle type, the crosslinked vinyl resin particle type, and the addition amount thereof are changed as shown in Table 4. ~ 4, 7-19, 21-27 were manufactured.

(Manufacturing method of toner 5)
After raising the temperature to 78 ° C., 20 parts by mass of the crystalline resin particle dispersion liquid 1 in terms of solid content was added over 20 minutes, and the particles were agglomerated to obtain a core particle dispersion liquid in the same manner as the toner 1. Toner 5 was manufactured.

(Manufacturing method of toner 6)
The toner 6 was produced in the same manner as the toner 5 except that the crystalline resin particle dispersion liquid 2 was used instead of the crystalline resin particle dispersion liquid 1.

(Manufacturing method of toner 20)
The toner 20 is the same as the toner 1 except that sol-gel silica (hydrophobicity 72%, number average particle size 100 nm) treated with hexamethyldisilazane (HMDS) is used instead of the vinyl resin particles 1. Manufactured.

[Coverage]
The coverage of the shell was determined from the cross section of the toner particles observed as follows.

<Method of observing the cross section of toner particles>
Equipment: Transmission electron microscope "JSM-7401F" (manufactured by JEOL Ltd.)
Sample: Section of toner particles stained with ruthenium tetroxide (RuO ₄ ) (section thickness: 60-100 nm)
Acceleration voltage: 30kV
Magnification: 10000 times Observation conditions: Transmission electron detector, bright field image

<Method for preparing toner particle sections>
1 to 2 mg of toner is spread out in a 10 mL sample bottle _{, treated under ruthenium tetroxide (RuO 4} ) vapor dyeing conditions as shown below, and then in the photocurable resin "D-800" (manufactured by JEOL Ltd.). And photo-cured to form blocks. Then, using a microtome equipped with diamond teeth, an ultrasliced sample having a thickness of 60 to 100 nm was cut out from the above block.

(Rutenium tetroxide treatment conditions)
The ruthenium tetroxide treatment is performed using a vacuum electron dyeing apparatus VSC1R1 (manufactured by Filgen Co., Ltd.). According to the equipment procedure, a sublimation chamber containing ruthenium tetroxide was installed in the main body of the dyeing apparatus, and after introducing toner or the above ultrathin section into the staining chamber, the dyeing conditions with ruthenium tetroxide were room temperature (24 to 25 ° C.). Staining was performed under the conditions of a concentration of 3 (300 Pa) and a time of 10 minutes.

<Observation of dispersed particles>
Within 24 hours after staining, the observation was performed with an electron microscope "JSM-7401F" (manufactured by JEOL Ltd.).
The measurement toner particle image was used for measurement by photographing 20 fields in which the diameter of the cross section of the toner particles was within the range of the median diameter (D50% diameter) ± 10% based on the volume of the toner particles. Hereinafter, the toner particles having 20 fields of view are referred to as "20 samples" or simply "samples".

<Measurement method of coverage>
The coverage of the shell in the toner particles was calculated from the cross section of the toner matrix particles.
The cross section of the toner matrix particles was photographed with an electron microscope JSM-7401F (manufactured by JEOL Ltd.) at an acceleration voltage of 30 kV at 10000 times, and the photographic image was photographed by the image processing analyzer LUZEX AP (manufactured by Nireco Co., Ltd.). The length of the shell region and the embedding resin interface and the circumference of the toner cross section were measured using.
The coverage of the shell was calculated by the following formula when the length of the interface between the shell region and the embedding resin was A and the peripheral length of the toner cross section was B.
(Coverage) = A / B x 100

《Evaluation》
[Evaluation method]
<Evaluation machine>
A test image was formed and evaluated by loading it into a developing device of a commercially available color multifunction device "bizhub PRO 1250" (manufactured by Konica Minolta).

<Low temperature fixability (under offset property)>
The under offset refers to an image defect that is peeled off from a transfer material such as recording paper because the toner layer is insufficiently melted by the heat applied when passing through the fixing machine.
The low-temperature fixability was evaluated by sequentially loading the toner produced above into a toner bottle and a developer into a developing machine in the above-mentioned developing apparatus. The evaluation machine was modified so that the fixing temperature, toner adhesion amount, and system speed could be set freely. Using NPI 128 g / m ² (manufactured by Nippon Paper Industries) as the evaluation paper, a solid image with a toner adhesion amount of 11.3 g / m ² is set at a fixing speed of 300 mm / s and the temperature of the fixing roller is set to 150 to 200 ° C. every 5 ° C. The lower limit of fixing temperature at which underoffset does not occur when fixing at a level was evaluated and used as an index of low-temperature fixability. The lower the lower limit temperature for fixing, the better the fixing property, and the temperature was 185 ° C. or lower.

<Heat-resistant storage (toner aggregation rate)>
Take 0.5 g of toner in a 10 mL glass bottle with an inner diameter of 21 mm, close the lid, shake with Tap Dencer KYT-2000 (manufactured by Seishin Enterprise Co., Ltd.) 600 times at room temperature, and then remove the lid at 57.5 ° C., 35. It was left in an environment of% RH for 2 hours. Next, place the toner on a sieve of 48 mesh (opening 350 μm), being careful not to crush the toner aggregates, set it on a powder tester (manufactured by Hosokawa Micron), and fix it with a holding bar and knob nut. After adjusting the vibration intensity to a feed width of 1 mm and applying vibration for 10 seconds, the ratio (mass%) of the amount of residual toner on the sieve was measured.
The toner aggregation rate was calculated by the following formula.
Toner aggregation rate (%) = mass of residual toner on the sieve (g) /0.5 (g) x 100
The calculated toner agglomeration rate was used to evaluate the heat-resistant storage property. In addition, the toner aggregation rate of 20% or less was regarded as acceptable.

<Transportability>
20000 copies of a 2% character chart were made in a printing environment of a high temperature and high humidity environment (30 ° C., 80% RH). After that, the maximum image density was measured by printing a solid image on A4 size high-quality paper (65 g / m ² ), and the relative reflection density based on the blank paper density was measured with the densitometer "RD-918" (manufactured by Macbeth). Was measured using. At this time, the automatic adjustment of the concentration was not performed except at the beginning. Passed with 1.40 or higher.

<White spot evaluation>
Using a blade and photoconductor that printed 250,000 sheets of A4 5% coverage character chart, count the number of white spots when 5000 sheets of 25% A3 chart of 3 vertical bands (solid) were passed. did.
10 or less white spots were accepted.

From Table 5, according to the present invention, a toner capable of achieving both low-temperature fixability and heat-resistant storage while suppressing white spot image defects after long-term use and maintaining good transferability due to the spacer effect can be obtained. It was shown that it can be provided.

1 Toner matrix particle 2 Core particle 3 Shell 31 Shell area

Claims (7)

A toner for electrostatic latent image development containing toner matrix particles having a core-shell structure and an external additive.
The toner base particles have core particles containing a vinyl resin and a shell that covers the surface of the core particles within a coverage range of 60 to 99%.
The shell contains an amorphous polyester resin and
The external additive contains crosslinked vinyl-based resin particles,
The cross-linked vinyl resin particles, number average particle diameter Ri range der of 30 to 300 nm,
The crosslinked vinyl-based resin particles contain a crosslinked resin containing a structural unit derived from a crosslinkable vinyl monomer and a non-crosslinkable resin containing a structural unit derived from a non-crosslinkable vinyl monomer.
The non-crosslinkable vinyl monomer is styrene and methyl methacrylate, and the content of the structural unit derived from the cross-linkable vinyl monomer is 100% by mass based on the non-crosslinkable vinyl monomer. an electrostatic latent image developing toner, characterized in der Rukoto the range of 5 to 30 mass%. The toner for electrostatic latent image development according to claim 1, wherein the shell covers the surface of the core particles within a coverage range of 70 to 95%. The toner for electrostatic latent image development according to claim 1 or 2, wherein the core particles contain a crystalline resin. The toner for electrostatic latent image development according to claim 3, wherein the crystalline resin contains a crystalline polyester resin. The toner for electrostatic latent image development according to claim 3 or 4, wherein the crystalline resin is a crystalline resin formed by bonding a vinyl-based polymerized segment and a polyester polymerized segment. The toner for electrostatic latent image development according to any one of claims 1 to 5, wherein the average particle size of the crosslinked vinyl resin particles is in the range of 50 to 200 nm. Claims 1 to 6 are characterized in that the crosslinked vinyl-based resin particles are contained in the range of 0.05 to 3.0% by mass with respect to the entire toner for electrostatic latent image development. The toner for electrostatic latent image development according to any one of the above items.

Images