JP7443709B2 - Toner for developing electrostatic latent images - Google Patents

Description

The present invention relates to a toner for developing electrostatic latent images. More specifically, the present invention relates to a toner for developing electrostatic latent images that can achieve both low-temperature fixability and image stability when an image with a low printing rate is output over a long period of time.

As a toner for developing electrostatic latent images (hereinafter simply referred to as "toner") used in electrophotographic image formation, it is There is a need to reduce thermal energy. In response to this, toners with even better low-temperature fixability are desired.

In order to meet the demand for low-temperature fixability, it is necessary to lower the melting temperature and melt viscosity of the binder resin. Toners for image development have been proposed.

However, when such a toner is used, there is a problem that the heat-resistant storage property of the toner and the storage property of the image deteriorate. To counter this problem, it has been proposed to improve the heat-resistant storage properties of toners and the storage stability of images by controlling the melting point and content of crystalline resins and the thermophysical properties of amorphous resins (for example, , Patent Document 1 and Patent Document 2).

However, even if the melting temperature and melt viscosity of the bulk toner are controlled, there are still problems with image stability, especially with the recent demand for long life. When outputting low-printing-rate images with little replacement of toner over a long period of time, the toner's charging performance and flow performance deteriorate with conventional toner, so it was necessary to refresh the toner in the developing machine by so-called waste burning. .

JP2006-251564A JP2017-9630A

The present invention was made in view of the above-mentioned problems and circumstances, and the object to be solved is to provide an electrostatic latent image that can achieve both low-temperature fixability and image stability when outputting images with low printing rate over a long period of time. The purpose of the present invention is to provide a developing toner.

In order to solve the above-mentioned problems, the inventor of the present invention, in the process of studying the causes of the above-mentioned problems, discovered that in a toner that uses a crystalline material to improve low-temperature fixability, the glass transition on the surface of the toner can be maintained until the heat-resistant storage property can be maintained. It was found that even if the temperature was raised, the external additive that adhered to the toner surface remained buried inside the toner. The present inventors not only designed the glass transition temperature of the toner, but also designed the toner to have a high elastic modulus at room temperature (the resin is in a glass state), thereby suppressing the embedding of external additives inside the toner and reducing the It has been found that stable images with little fluctuation in the output image can be obtained over a long period of time even when the image has a low printing rate.
That is, the above-mentioned problems related to the present invention are solved by the following means.

1. A toner for developing an electrostatic latent image, comprising toner particles comprising at least an amorphous resin (I) , a crystalline material, a release agent, and an external additive,
The crystalline material is a hybrid crystalline polyester in which an amorphous resin (II) segment and a crystalline polyester segment are combined, or a fatty acid amide,
The melting point of the crystalline material is within the range of 70 to 120°C, and
An electrostatic latent material characterized in that the storage elastic modulus at T _max is within the range of 4.0×10 ⁸ to 1.0×10 ⁹ Pa, where T _max is the temperature at which the loss modulus reaches a maximum. Toner for image development.

2. 2. The toner for developing electrostatic latent images according to item 1, which contains terphenyl, abietic acid, or liquid paraffin .

3. The toner for developing electrostatic latent images according to item 1 or 2, wherein the storage elastic modulus at T _max is within the range of 5.0 x 10 ⁸ to 1.0 x 10 ⁹ Pa. .

4. The toner for developing electrostatic latent images according to item 1 or 2, wherein the storage elastic modulus at T _max is within the range of 6.0 x 10 ⁸ to 1.0 x 10 ⁹ Pa. .

5. The toner for developing an electrostatic latent image according to any one of items 1 to 4 , wherein the amorphous resin (II) segment is a styrene acrylic resin segment .

6. The toner for developing an electrostatic latent image according to any one of Items 1 to 5, wherein the amorphous resin (I) contains an amorphous vinyl resin.

7. The electrostatic latent according to item 2, characterized in that the mass ratio value of the terphenyl, the abietic acid, or the liquid paraffin to the crystalline material is within the range of 0.08 to 0.30. Toner for image development.

8. An electrostatic latent image developing toner comprising toner particles comprising at least an amorphous resin, a crystalline material, a release agent, and an external additive,
The crystalline material is a hybrid crystalline polyester in which a styrene acrylic resin segment and a crystalline polyester segment are combined,
The melting point of the crystalline material is within the range of 70 to 120°C,
The electrostatic latent image developing toner contains liquid paraffin,
The molecular weight of the liquid paraffin is within the range of 240 to 550, and
An electrostatic latent material characterized in that the storage elastic modulus at T max is within the range of 4.0×10 ₈ ^to 1.0×10 ⁹ Pa, where T _max is the temperature at which the loss modulus reaches a maximum. Toner for image development.

By means of the above means of the present invention, it is possible to provide a toner for developing electrostatic latent images that can achieve both low-temperature fixability and image stability when an image with a low printing rate is output over a long period of time.

Although the mechanism of expression or action of the effects of the present invention is not clear, it is speculated as follows.
Adding temperature to toner has the effect of rapidly lowering the viscosity in a temperature range higher than the temperature at which molecular motion is most freed from constraints (T _max ), and by controlling this temperature T _max , it is possible to achieve an excellent low temperature. Provides good fixing properties.

However, even if T _max was controlled, the stability of the image was insufficient when an image with a low printing rate was output for a long period of time. The reason for this is that even in a temperature range lower than T _max , some of the crystalline material is compatible with the amorphous binder resin and the storage elastic modulus is low, so the external additives are buried inside the toner. We speculate that this is because the It is presumed that by making the toner have an elastic modulus higher than a certain value, it is possible to suppress the toner from being buried inside the toner and improve the stability of the output image.

The toner for developing electrostatic latent images of the present invention is a toner for developing electrostatic latent images containing toner particles consisting of at least an amorphous resin (I) , a crystalline material, a release agent, and an external additive, the toner for developing electrostatic latent images comprising: The crystalline material is a hybrid crystalline polyester in which an amorphous resin (II) segment and a crystalline polyester segment are combined, or a fatty acid amide, and the melting point of the crystalline material is within the range of 70 to 120°C, and The storage elastic modulus at T _max is within the range of 4.0×10 ⁸ to 1.0×10 ⁹ Pa, where T _max is the temperature at which the loss modulus reaches a maximum. This feature is a technical feature that is common to or corresponds to each embodiment (form) described below.

As an embodiment of the present invention, it is preferable that an elastic modulus improver is included from the viewpoint of exerting the effects of the present invention.
Further, the storage modulus at T _max is preferably 5.0×10 ⁸ Pa or more, more preferably 6.0×10 ⁸ Pa or more. The effect of suppressing embedding of external additives can be obtained.
Further, in the present invention, it is preferable that the crystalline material is a fatty acid amide or a crystalline polyester from the viewpoint of achieving both heat-resistant storage property and low-temperature fixability. This is because these compounds exhibit appropriate compatibility with the binder resin.
In an embodiment of the present invention, it is preferable that the amorphous resin contains an amorphous vinyl resin from the viewpoint of long-term image stability. This is because since the binder resin is a vinyl resin, it exhibits appropriate compatibility with the crystalline material.
Further, it is preferable that the mass ratio value of the elastic modulus improver to the crystalline material is within the range of 0.08 to 0.30, since the effect of increasing the elastic modulus of the glass state of the toner can be obtained. .
Further, it is preferable that the elastic modulus improver is liquid paraffin from the viewpoint of low-temperature fixability and long-term image stability. Liquid paraffin is preferable because it can increase the elastic modulus of the glass state of the toner without increasing the viscosity when the toner is melted.

Hereinafter, the present invention, its constituent elements, and forms and aspects for carrying out the present invention will be described in detail. In this application, "~" is used to include the numerical values described before and after it as a lower limit value and an upper limit value.

<<Overview of toner for developing electrostatic latent images of the present invention>>
The toner for developing electrostatic latent images of the present invention is a toner for developing electrostatic latent images containing toner particles consisting of at least an amorphous resin (I) , a crystalline material, a release agent, and an external additive, the toner for developing electrostatic latent images comprising: The crystalline material is a hybrid crystalline polyester in which an amorphous resin (II) segment and a crystalline polyester segment are combined, or a fatty acid amide, and the melting point of the crystalline material is within the range of 70 to 120°C, and The storage elastic modulus at T _max is within the range of 4.0×10 ⁸ to 1.0×10 ⁹ Pa, where T _max is the temperature at which the loss modulus reaches a maximum.

The electrostatic latent image developing toner (toner) of the present invention contains a crystalline material having a melting point within the range of 70 to 120°C. If the melting point is below 70°C, heat-resistant storage properties will deteriorate. If the melting point exceeds 120° C., low-temperature fixability deteriorates.

However, even if the glass transition temperature of the toner surface is raised to the point where heat-resistant storage properties are maintained for toners with improved low-temperature fixing properties using crystalline materials, the image quality when outputting images with a low printing rate over a long period of time is Stability was insufficient. The reason for this is that even in a temperature range lower than T _max , a part of the crystalline material is compatible with the amorphous binder resin, resulting in a low storage modulus, and therefore the external additive It is presumed that this is because the particles are buried inside the toner. The inventors have discovered that by appropriately designing not only the glass transition temperature of the toner but also the elastic modulus of the toner, it is possible to achieve both low-temperature fixability and long-term output image stability.

[Storage modulus and loss modulus]
In dynamic viscoelasticity measurements, the storage modulus is the component of the energy generated by external force and strain on an object that is stored inside the object (elastic behavior), and the loss modulus is the component that diffuses to the outside (viscous behavior). behavior). In temperature dispersion measurement, as the measurement temperature rises, the intricately entangled polymer chains of the resin constituting the toner gradually start molecular motion, and the molecular motion reaches its maximum at the temperature T _max where the loss modulus reaches its maximum. It is known to free you from bondage.

Generally, a toner containing a crystalline material has the effect of rapidly lowering the viscosity in a temperature range higher than T _max and has excellent low-temperature fixability. However, even in a temperature range lower than T _max , a part of the crystalline material is compatible with the amorphous binder resin, so that the storage modulus becomes low. Therefore, the external additives are likely to be buried, which is presumed to be the cause of various image defects.

A high storage modulus at T _max indicates that a high modulus of elasticity can be maintained up to the temperature at which the resin starts to rapidly decrease in viscosity. In other words, the fact that it contains a crystalline material with a melting point of 70 to 120°C and has a storage modulus at T _max of 4.0×10 ⁸ Pa or more means that it has low-temperature fixing properties while also being below the glass transition temperature. This shows that since it has a high elastic modulus, it is possible to suppress the external additive from being buried inside the toner, and it is possible to obtain stable images over a long period of time.

In the present invention, the storage elastic modulus at T _max is preferably 5.0 x 10 ⁸ Pa or more, and 6.0 x 10 ⁸ Pa or more has the effect of suppressing embedding of the external additive. It is preferable because it can be obtained. The upper limit of the storage modulus at T _max is determined by the material used, but is approximately 1.0×10 ⁹ Pa for materials normally used for toner.

(Measurement method of storage modulus and loss modulus)
0.2 g of toner is weighed out and pressure molded by applying a pressure of 25 MPa using a compression molding machine to produce cylindrical pellets with a diameter of 10 mm. Using a rheometer "ARES G2" (manufactured by TA instrument), measurements are performed at a frequency of 1 Hz using a set of upper and lower parallel plates with a diameter of 8 mm.

Sample setting is carried out at 100° C., and after the gap between the plates is set to 1.4 mm, the sample protruding from between the plates is scraped off, and the gap is set to 1.1 mm. Thereafter, the pellet was cooled to 25° C. while applying an axial force, and left to stand for 10 minutes. After that, the axial force was stopped and the temperature was measured for storage modulus (G') and loss modulus (G'') from 25°C to 100°C.The heating rate was 3°C/min. A dispersion curve is obtained. Based on the temperature dispersion curve, the temperature T _max at which the loss modulus reaches a maximum and the storage modulus at T _max can be measured.
Note that when a plurality of temperatures showing a maximum are obtained due to temperature increase, the temperature showing a maximum on the lower temperature side is defined as T _max .

Detailed measurement conditions are shown below.
Frequency: 1Hz
Ramp rate: 3°C/min Axial force: 0g
Sensitivity: 10g
Initial strain: 0.01%
Strain adjustment: 30.0%
Minimum strain: 0.01%
Maximum strain: 10.0%
Minimum torque: 1g・cm
Maximum torque: 80g・cm
Measurement interval (Sampling interval): 1.0°C/pt

[Melting point]
The crystalline material used in the present invention has a melting point in the range of 70 to 120°C, and refers to a material that has a clear endothermic peak rather than a step-like endothermic change in differential scanning calorimetry (DSC). Specifically, a clear endothermic peak means a peak whose half-value width is within 15° C. when measured by DSC at a temperature increase rate of 10° C./min.
The melting point of the toner can be measured by DSC as follows.
5 mg of the crystalline material is sealed in an aluminum pan (KITNO.B0143013), set in a sample holder of a thermal analyzer "Diamond DSC" (manufactured by PerkinElmer), and heated. During the first heating, the peak top temperature of the endothermic peak when the temperature is raised from 0° C. to 100° C. at a heating rate of 10° C./min is defined as the melting point of the crystalline material. In addition, when multiple endothermic peaks are observed, the peak top temperature of the endothermic peak located at the highest temperature is taken as the melting point.

<Details of the toner for developing electrostatic latent images of the present invention>
The toner for developing an electrostatic latent image of the present invention is a toner for developing an electrostatic latent image containing toner particles consisting of at least an amorphous resin, a crystalline material, a release agent, and an external additive, the toner comprising the crystalline material. When the melting point of is within the range of 70 to 120 ° C. and the temperature at which the loss modulus reaches a maximum is T _max , the storage modulus at T _max is 4.0 × 10 ⁸ Pa or more. Features.

In the present invention, the toner is an aggregate of toner particles, and the toner particles are composed of toner base particles and an external additive attached to the surface of the toner base particles.
Furthermore, the toner may be a one-component developer or a two-component developer. A one-component developer is composed only of toner particles, and a two-component developer is composed of toner particles and carrier particles.

<Toner base particles>
The toner base particles according to the present invention contain at least a crystalline material, an amorphous resin, and a release agent. Furthermore, it is preferable to contain liquid paraffin.

[Crystalline material]
The crystalline material is a material that does not impair the fluidity of the toner powder at storage temperatures and contributes to sharp melting or rapid fixing of the toner during heat fixing.
The crystalline material used in the present invention has a melting point within the range of 70 to 120°C. The temperature is preferably within the range of 75 to 100°C, and more preferably within the range of 75 to 95°C. If the melting point is below 70°C, heat-resistant storage properties will deteriorate. If the melting point exceeds 120° C., low-temperature fixability deteriorates.
Among such materials, it is preferable that the crystalline material is a fatty acid amide or a crystalline polyester from the viewpoint of achieving both heat-resistant storage property and low-temperature fixability. This is because both compounds exhibit appropriate compatibility with the binder resin.

(fatty acid amide)
The fatty acid amide used in the present invention is preferably a saturated fatty acid amide compound represented by the following formula (1) or formula (2) having a melting point within the range of 70 to 120°C.
R ₁ -CO-NH-R ₂ formula (1)
R ₃ -CO-NH ₂ formula (2)
(In formula (1) and formula (2), R ₁ to R ₃ represent a divalent saturated hydrocarbon group having 1 to 30 carbon atoms. R ₁ to R ₃ may be the same or different. )
A monoamide compound having a primary amide group at the terminal and having a structure represented by formula (2) is preferred from the viewpoint of being superior in compatibility with the resin and being able to further improve the low-temperature fixability of the toner.

The saturated fatty acid amide compound having a melting point within the range of 70 to 120°C is not particularly limited and can be appropriately selected depending on the purpose, such as palmitic acid amide, stearic acid amide, arachidic acid amide, behenin. A primary amide compound in which a saturated aliphatic compound having 10 to 30 carbon atoms is amidated, such as acid amide, ligulinoceric acid amide, or N-palmityl palmitic acid amide, N-palmityl stearic acid amide, N-stearyl arachiamide Examples include secondary amide compounds such as dinic acid amide, N-stearyl stearic acid amide, N-palmityl oleic acid amide, and N-stearyl oleic acid amide.

The saturated fatty acid amide compounds may be used alone or in combination of two or more.
The blending amount is preferably within the range of 1 to 25% by mass based on the total amount of the toner. More preferably, it is within the range of 3 to 10% by mass.
If the amount is 1% by mass or more, a sufficient low-temperature fixing effect can be obtained. On the other hand, if it is 25% by mass or less, the offset properties and heat-resistant storage stability of the toner are good.

(crystalline polyester)
Preferably, crystalline polyester is used as the crystalline material. Crystalline polyester can also function as a binder resin.
The crystalline polyester used in the present invention is obtained by a polycondensation reaction between a dihydric or higher carboxylic acid (polycarboxylic acid) and a divalent or higher alcohol (polyhydric alcohol).

Examples of the polyhydric carboxylic acids include dicarboxylic acids. The dicarboxylic acid may be one or more types, preferably an aliphatic dicarboxylic acid, and may further contain an aromatic dicarboxylic acid. The aliphatic dicarboxylic acid is preferably a linear type from the viewpoint of improving the crystallinity of the crystalline polyester.

Examples of the aliphatic dicarboxylic acids mentioned above include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decane Dicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid (dodecanedioic acid), 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1 , 18-octadecanedicarboxylic acid, lower alkyl esters thereof, and acid anhydrides thereof. Among them, aliphatic dicarboxylic acids having 6 or more carbon atoms and 16 or less carbon atoms are preferred, and aliphatic dicarboxylic acids having 10 or more carbon atoms and 14 or less carbon atoms are more preferred, from the viewpoint of easily achieving both low-temperature fixability and transferability. preferable.

Examples of the aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, t-butyl isophthalic acid, 2,6-naphthalenedicarboxylic acid and 4,4'-biphenyldicarboxylic acid. Among these, terephthalic acid, isophthalic acid, or t-butyl isophthalic acid is preferred from the viewpoint of easy availability and emulsification.

The content of the aliphatic dicarboxylic acid-derived structural units relative to the dicarboxylic acid-derived structural units in the crystalline polyester is preferably 50 mol% or more, from the viewpoint of ensuring sufficient crystallinity of the crystalline polyester, and 70% by mole or more. It is more preferably at least 80 mol%, even more preferably at least 80 mol%, and particularly preferably at least 100 mol%.

Examples of the polyhydric alcohol component include diols. The diol may be one or more types, preferably an aliphatic diol, and may further contain other diols. The aliphatic diol is preferably a linear type from the viewpoint of improving the crystallinity of the crystalline polyester.

Examples of the aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8 -Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18 - Octadecanediol and 1,20-eicosandiol. Among these, aliphatic diols having 2 or more carbon atoms and 12 or less carbon atoms are preferred, and aliphatic diols having 4 or more carbon atoms and 6 or less carbon atoms are more preferred, from the viewpoint of easily achieving both low-temperature fixability and transferability. preferable.

Examples of other diols include diols with double bonds and diols with sulfonic acid groups. Specifically, examples of diols having double bonds include 2-butene-1,4-diol, 3-butene-1,6-diol, and 4-butene-1,8-diol.

The content of aliphatic diol-derived structural units relative to diol-derived structural units in the crystalline polyester should be 50 mol% or more from the viewpoint of improving the low-temperature fixing properties of the toner and the glossiness of the finally formed image. is preferable, more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 100 mol%.

The ratio of the diol and the dicarboxylic acid in the crystalline polyester monomer is 2.0/1 in terms of the equivalent ratio [OH]/[COOH] of the hydroxy group [OH] of the diol and the carboxy group [COOH] of the dicarboxylic acid. It is preferably .0 or more and 1.0/2.0 or less, more preferably 1.5/1.0 or more and 1.0/1.5 or less, 1.3/1.0 or more. It is particularly preferable that the ratio is 1.0/1.3 or less.

The monomer constituting the crystalline polyester preferably contains a linear aliphatic monomer in an amount of 50% by mass or more, more preferably 80% by mass or more. When an aromatic monomer is used, the melting point of the crystalline polyester tends to be high, and when a branched aliphatic monomer is used, the crystallinity tends to be low. Therefore, it is preferable to use a linear aliphatic monomer as the monomer. From the viewpoint of maintaining the crystallinity of the crystalline polyester in the toner, the linear aliphatic monomer is preferably used in an amount of 50% by mass or more, more preferably 80% by mass or more.

The crystalline polyester can be synthesized by polycondensing (esterifying) the polyhydric carboxylic acid and polyhydric alcohol using a known esterification catalyst.

The catalyst that can be used for the synthesis of crystalline polyester may be one or more types, and examples thereof include alkali metal compounds such as sodium and lithium; compounds containing Group 2 elements such as magnesium and calcium; aluminum, zinc, Included are metal compounds such as manganese, antimony, titanium, tin, zirconium, and germanium; phosphorous acid compounds; phosphoric acid compounds; and amine compounds.

Specifically, examples of tin compounds include dibutyltin oxide, tin octylate, tin dioctylate, and salts thereof. Examples of titanium compounds include titanium alkoxides such as tetra-n-butyl titanate, tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate; titanium acylates such as polyhydroxytitanium stearate; and titanium tetraacetylacetonate, titanium lactate, Includes titanium chelates such as titanium triethanolaminate. Examples of germanium compounds include germanium dioxide, and examples of aluminum compounds include oxides such as polyaluminum hydroxide, aluminum alkoxides, and tributyl aluminate.

The polymerization temperature of the crystalline polyester is preferably 150°C or higher and 250°C or lower. Further, the polymerization time is preferably 0.5 hours or more and 10 hours or less. During the polymerization, the pressure inside the reaction system may be reduced if necessary.

The content of the crystalline polyester in the toner base particles is preferably 2% by mass or more and 20% by mass or less, more preferably 7% by mass or more and 15% by mass from the viewpoint of obtaining sufficient low-temperature fixability. preferable. If the content is 2% by mass or more, a sufficient plasticizing effect can be obtained and sufficient low-temperature fixing properties can be obtained. When the content is 20% by mass or less, the toner has sufficient thermal stability and stability against physical stress. In the above preferred range or more preferred range, for example, by selecting the configuration of the amorphous resin and an appropriate manufacturing method, it becomes easier to control the viscoelasticity to a preferred range.

Further, the number average molecular weight (Mn) of the crystalline polyester is preferably 8,500 or more and 12,500 or less, more preferably 9,000 or more and 11,000 or less. If the weight average molecular weight Mw or Mn is large, the strength of the fixed image may be insufficient, the crystalline resin may be crushed during agitation of the developer, and the glass transition temperature Tg of the toner may be lowered due to excessive plasticizing effect. There is no decrease in thermal stability. Furthermore, if the above Mw and Mn are not too large, sharp melt properties will not be difficult to develop or the fixing temperature will not become too high. The above Mw and Mn can be determined from the molecular weight distribution measured by gel permeation chromatography (GPC) as follows.

The sample is added to tetrahydrofuran (THF) to a concentration of 0.1 mg/mL, heated to 40°C to dissolve, and then processed through a membrane filter with a pore size of 0.2 μm to prepare a sample solution. . Using a GPC device HLC-8220GPC (manufactured by Tosoh Corporation) and a column "TSKgelSuperH3000" (manufactured by Tosoh Corporation), THF is flowed as a carrier solvent at a flow rate of 0.6 mL/min while maintaining the column temperature at 40° C. 100 μL of the prepared sample solution is injected into the GPC device together with the carrier solvent, and the sample is detected using a differential refractive index detector (RI detector). Then, the molecular weight distribution of the sample is calculated using a calibration curve measured using 10 points of monodisperse polystyrene standard particles. At this time, in the data analysis, if a peak caused by the filter is confirmed, the area before the peak is set as the baseline.

(hybrid polyester)
The structure and constituent monomers of the crystalline polyester affect the degree of crystallinity and heat of fusion of the crystalline polyester. From the viewpoint of adjusting the degree of crystallinity of the crystalline polyester to a preferable range for fixing, the crystalline polyester is preferably a hybrid crystalline polyester (hereinafter also simply referred to as "hybrid resin"). The hybrid resin may be one type or more than one type. Alternatively, the hybrid resin may be substituted for the entire amount of the crystalline polyester, or may be partially substituted (or used in combination).

A hybrid resin is a resin in which a crystalline polyester segment (also referred to as a polyester polymerization segment) and a resin unit other than the crystalline polyester (also referred to as another polymerization segment) are chemically bonded. In this embodiment, the hybrid resin is a resin in which a crystalline polyester segment and an amorphous resin segment are chemically bonded. The crystalline polyester segment means a portion derived from the above-mentioned crystalline polyester. That is, it means a molecular chain having the same chemical structure as the molecular chain constituting the crystalline polyester described above. Moreover, the amorphous resin segment means a portion derived from an amorphous resin. That is, it means a molecular chain having the same chemical structure as the molecular chain constituting the amorphous resin described later.

The weight average molecular weight Mw of the hybrid resin is preferably 5,000 or more and 100,000 or less, more preferably 7,000 or more and 50,000 or less, from the viewpoint of reliably achieving both sufficient low-temperature fixability and excellent long-term storage stability. It is preferably 8,000 or more and particularly preferably 20,000 or less. By setting the Mw of the hybrid resin to 100,000 or less, sufficient low-temperature fixability can be obtained. On the other hand, by setting the Mw of the hybrid resin to 5000 or more, excessive compatibility between the hybrid resin and the amorphous resin is suppressed during toner storage, and image defects due to toner adhesion are effectively prevented. can be suppressed.

The crystalline polyester segment may be, for example, a resin having a structure in which other components are copolymerized on the main chain of the crystalline polyester segment, or a resin in which the crystalline polyester segment is copolymerized with the main chain consisting of other components. It may be a resin having a structure. The crystalline polyester segment can be synthesized from the polycarboxylic acid and polyhydric alcohol described above in the same manner as the crystalline polyester described above.

From the viewpoint of imparting sufficient crystallinity to the hybrid resin, the content of the crystalline polyester segment in the hybrid resin is preferably 80% by mass or more and less than 98% by mass, and preferably 90% by mass or more and less than 95% by mass. It is more preferable that the content is 91% by mass or more and less than 93% by mass. The constituent components of each segment in the hybrid resin (or in the toner) and their content can be determined by, for example, nuclear magnetic resonance (NMR) or methylation reaction pyrolysis gas chromatography/mass spectrometry (P-GC/MS). It can be identified by using known analysis methods such as.

It is preferable that the crystalline polyester segment further contains a monomer having an unsaturated bond, from the viewpoint of introducing a chemical bonding site with the amorphous resin segment into the segment. Monomers having unsaturated bonds are, for example, polyhydric alcohols having double bonds, such as methylene succinic acid, fumaric acid, maleic acid, 3-hexenedioic acid, 3-octenedioic acid, etc. Polyhydric carboxylic acids having double bonds; include 2-butene-1,4-diol, 3-butene-1,6-diol and 4-butene-1,8-diol. The content of the structural unit derived from the monomer having the unsaturated bond in the crystalline polyester segment is preferably 0.5% by mass or more and 20% by mass or less.

The above hybrid resin may be a block copolymer or a graft copolymer, but the graft copolymer makes it easier to control the orientation of the crystalline polyester segments, and the hybrid resin Preferably, the crystalline polyester segment is grafted in a comb shape with a polymerized segment other than polyester as the main chain and a polyester resin segment as a side chain. That is, the hybrid resin is preferably a graft copolymer having the above-mentioned amorphous resin segment as a main chain and the above-mentioned crystalline polyester segment as a side chain.

In addition, a functional group such as a sulfonic acid group, a carboxy group, or a urethane group may be further introduced into the hybrid resin. The functional group may be introduced into the crystalline polyester segment or into the amorphous resin segment.

The amorphous resin segment increases the affinity between the amorphous resin and the hybrid resin that constitute the binder resin. As a result, the hybrid resin is easily incorporated into the amorphous resin, and the toner charging uniformity is further improved. The constituent components of the amorphous resin segment in the hybrid resin (or in the toner) and their content can be identified by using known analytical methods such as NMR and methylation reaction P-GC/MS. .

Further, the amorphous resin segment preferably has a glass transition temperature (Tg) of 30°C or more and 80°C or less in the first temperature raising process of DSC, similar to the above-mentioned amorphous resin, and 40°C or more and 80°C or less. It is more preferable that the temperature is higher than or equal to 65°C. Note that the glass transition temperature (Tg) can be measured by the method described above.

The amorphous resin segment is composed of the same type of resin as the amorphous resin (in this embodiment, vinyl resin) contained in the binder resin, which increases the affinity with the binder resin and improves the toner's affinity. This is preferable from the viewpoint of improving charging uniformity. By adopting such a form, the affinity between the hybrid resin and the amorphous resin is further improved. "Resins of the same type" means resins that have characteristic chemical bonds in their repeating units.

“Characteristic chemical bonds” are “polymer According to "classification". Namely, polyacrylic, polyamide, polyanhydride, polycarbonate, polydiene, polyester, polyhaloolefin, polyimide, polyimine, polyketone, polyolefin, polyether, polyphenylene, polyphosphazene, polysiloxane, polystyrene, polysulfide, polysulfone, polyurethane, polyurea. The chemical bonds that make up the polymers classified by a total of 22 types, including polyvinyl, polyvinyl, and other polymers, are referred to as "characteristic chemical bonds."

In addition, in the case where the resin is a copolymer, "the same type of resin" refers to the chemical structure of multiple monomer species constituting the copolymer, when the monomer species having the above chemical bond is used as a constituent unit, Refers to resins that share a common chemical bond. Therefore, even if the properties of the resins themselves are different, or the molar ratios of the monomers constituting the copolymer are different, as long as they have a characteristic chemical bond in common, the same type of Considered as resin.

For example, a resin (or resin segment) formed from styrene, butyl acrylate, and acrylic acid, and a resin (or resin segment) formed from styrene, butyl acrylate, and methacrylic acid have at least the chemical bonds that constitute polyacrylic. Therefore, these are the same type of resin. To further illustrate, a resin (or resin segment) formed by styrene, butyl acrylate, and acrylic acid and a resin (or resin segment) formed by styrene, butyl acrylate, acrylic acid, terephthalic acid, and fumaric acid are mutually exclusive. As a common chemical bond, it has at least a chemical bond that constitutes polyacrylic. Therefore, these are the same type of resin.

Examples of amorphous resin segments include styrene-acrylic resin units, vinyl resin units, urethane resin units, and urea resin units. Among these, a vinyl resin unit is preferred from the viewpoint of easy control of thermoplasticity. The vinyl resin unit can be synthesized in the same manner as the vinyl resin described above.

The content of the structural unit derived from the styrene monomer in the amorphous resin segment is preferably 40% by mass or more and 90% by mass or less from the viewpoint of making it easy to control the plasticity of the hybrid resin. Further, from the same viewpoint, the content of the structural unit derived from the (meth)acrylic acid ester monomer in the amorphous resin segment is preferably 10% by mass or more and 60% by mass or less.

Furthermore, it is preferable that the amorphous resin segment further contains the above-mentioned amphoteric compound in the monomer from the viewpoint of introducing a chemical bonding site with the crystalline polyester segment into the amorphous resin segment. The content of the structural unit derived from the amphoteric compound in the amorphous resin segment is preferably 0.5% by mass or more and 20% by mass or less.

The content of the amorphous resin segment in the hybrid resin is preferably 3% by mass or more and less than 15% by mass, and 5% by mass or more and less than 10% by mass, from the viewpoint of imparting sufficient crystallinity to the hybrid resin. More preferably, the content is 7% by mass or more and less than 9% by mass.

The above-mentioned hybrid resin can be manufactured by, for example, the first to third manufacturing methods shown below.

The first manufacturing method is a method of manufacturing a hybrid resin by performing a polymerization reaction to synthesize a crystalline polyester segment in the presence of a previously synthesized amorphous resin segment.

In this method, first, the monomers constituting the above-mentioned amorphous resin segment (preferably vinyl monomers such as styrene monomers and (meth)acrylic acid ester monomers) are subjected to an addition reaction to form a non-crystalline resin segment. Synthesize crystalline resin segments. Next, in the presence of the amorphous resin segment, a polyhydric carboxylic acid and a polyhydric alcohol are subjected to a polymerization reaction to synthesize a crystalline polyester segment. At this time, a hybrid resin is synthesized by causing a condensation reaction between a polyhydric carboxylic acid and a polyhydric alcohol, and by causing an addition reaction of the polyhydric carboxylic acid or polyhydric alcohol to the amorphous resin segment.

In the first manufacturing method, it is preferable to incorporate into the crystalline polyester segment or the amorphous resin segment a site that allows these segments to react with each other. Specifically, when synthesizing the amorphous resin segment, the above-mentioned amphoteric compound is also used in addition to the monomers constituting the amorphous resin segment. When the amphoteric compound reacts with the carboxy group or hydroxyl group in the crystalline polyester segment, the crystalline polyester segment is chemically and quantitatively bonded to the amorphous resin segment. Further, when synthesizing the crystalline polyester segment, the monomer may further contain the above-mentioned compound having an unsaturated bond.

According to the first manufacturing method, a hybrid resin having a structure (graft structure) in which a crystalline polyester segment is molecularly bonded to an amorphous resin segment can be synthesized.

The second manufacturing method is a method in which a crystalline polyester segment and an amorphous resin segment are respectively formed and then bonded to each other to manufacture a hybrid resin.

In this method, first, a polyhydric carboxylic acid and a polyhydric alcohol are subjected to a condensation reaction to synthesize a crystalline polyester segment. In addition, separate from the reaction system for synthesizing the crystalline polyester segment, the monomer constituting the amorphous resin segment described above is subjected to addition polymerization to synthesize the amorphous resin segment. At this time, it is preferable to incorporate a site in which the crystalline polyester segment and the amorphous resin segment can react with each other into one or both of the crystalline polyester segment and the amorphous resin segment as described above.

Next, by reacting the synthesized crystalline polyester segment and the amorphous resin segment, a hybrid resin having a structure in which the crystalline polyester segment and the amorphous resin segment are molecularly bonded can be synthesized.

In addition, if the above-mentioned reactive site is not incorporated into either the crystalline polyester segment or the amorphous resin segment, in a system where the crystalline polyester segment and the amorphous resin segment coexist, the crystalline polyester segment Alternatively, a method may be adopted in which a compound having a site capable of binding to both the amorphous resin segment and the amorphous resin segment is introduced. Thereby, a hybrid resin having a structure in which a crystalline polyester segment and an amorphous resin segment are molecularly bonded via the compound can be synthesized.

The third manufacturing method is a method of manufacturing a hybrid resin by performing a polymerization reaction to synthesize an amorphous resin segment in the presence of a crystalline polyester segment.

In this method, first, a polyhydric carboxylic acid and a polyhydric alcohol are subjected to a condensation reaction and polymerized to synthesize a crystalline polyester segment. Next, in the presence of the crystalline polyester segment, monomers constituting the amorphous resin segment are subjected to a polymerization reaction to synthesize an amorphous resin segment. At this time, as in the first manufacturing method, it is preferable to incorporate into the crystalline polyester segment or the amorphous resin segment a site that allows these segments to react with each other.
By the above method, a hybrid resin having a structure (graft structure) in which an amorphous resin segment is molecularly bonded to a crystalline polyester segment can be synthesized.

Among the first to third manufacturing methods described above, the first manufacturing method is used because it is easy to synthesize a hybrid resin having a structure in which a crystalline polyester chain is grafted onto an amorphous resin chain, and the production process can be simplified. preferable. In the first manufacturing method, since the amorphous resin segments are formed in advance and then the crystalline polyester segments are bonded together, the orientation of the crystalline polyester segments tends to be uniform. Therefore, it is preferable from the viewpoint of reliably synthesizing a hybrid resin suitable for the above-mentioned toner.

[Amorphous resin]
The toner of the present invention contains an amorphous resin as a binder resin. Amorphous resin is resin that does not have crystallinity, unlike crystalline resin. For example, the amorphous resin is a resin that does not have a melting point and has a relatively high glass transition temperature (Tg) when performing differential scanning calorimetry (DSC) of the amorphous resin or toner particles.

The Tg of the amorphous resin is preferably 35°C or higher and 80°C or lower, particularly preferably 45°C or higher and 65°C or lower.
The glass transition temperature can be measured according to the method (DSC method) specified in ASTM (American Society for Testing and Materials Standards) D3418-82. For the measurement, a DSC-7 differential scanning calorimeter (manufactured by PerkinElmer), a TAC7/DX thermal analyzer controller (manufactured by PerkinElmer), or the like can be used.

The amorphous resin may be one type or more than one type. Examples of amorphous resins include vinyl resins, urethane resins, urea resins, and amorphous polyesters such as styrene-acrylic modified polyesters. In this embodiment, the amorphous resin preferably includes an amorphous vinyl resin (hereinafter also simply referred to as "vinyl resin") from the viewpoint of easy control of thermoplasticity.

The vinyl resin is, for example, a polymer of a vinyl compound, and examples thereof include acrylic ester resin, styrene-acrylic ester resin, and ethylene-vinyl acetate resin. Among these, styrene-acrylic acid ester resin (styrene acrylic resin) is preferred from the viewpoint of plasticity during heat fixing.

Styrene acrylic resin is formed by addition polymerizing at least a styrene monomer and a (meth)acrylic acid ester monomer. Styrene monomers include styrene represented by the structural formula of CH ₂ ═CH—C ₆ H ₅ as well as styrene derivatives having known side chains and functional groups in the styrene structure.

In addition, the (meth)acrylic acid ester monomer is CH(R ₁ )=CHCOOR ₂ (R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 1 or more and 24 or less carbon atoms. In addition to acrylic esters and methacrylic esters represented by (represented by), acrylic ester derivatives and methacrylic ester derivatives having known side chains and functional groups in the structure of these esters are also included.

Examples of styrene monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p- Included are tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene and pn-dodecylstyrene.

Examples of (meth)acrylic ester monomers include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl Acrylic acid ester monomers such as acrylate and phenyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate , phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, and other methacrylic acid esters;

In addition, in this specification, "(meth)acrylic acid ester monomer" is a general term for "acrylic acid ester monomer" and "methacrylic acid ester monomer", and one or both of them are means. For example, "methyl (meth)acrylate" means one or both of "methyl acrylate" and "methyl methacrylate."

The above-mentioned (meth)acrylic acid ester monomer may be one type or more than one type. For example, forming a copolymer using a styrene monomer and two or more types of acrylic acid ester monomers, or forming a copolymer using a styrene monomer and two or more types of methacrylic acid ester monomers. It is possible to form a copolymer, or to form a copolymer by using a styrene monomer, an acrylic ester monomer, and a methacrylic ester monomer together.

From the viewpoint of controlling the plasticity of the amorphous resin, the content of structural units derived from styrene monomer in the amorphous resin is preferably 40% by mass or more and 90% by mass or less. Further, the content of structural units derived from the (meth)acrylic acid ester monomer in the amorphous resin is preferably 10% by mass or more and 60% by mass or less.

The amorphous resin may further contain a structural unit derived from a monomer other than the styrene monomer and (meth)acrylic acid ester monomer. The other monomer is preferably a compound that forms an ester bond with a hydroxy group (-OH) derived from a polyhydric alcohol or a carboxy group (-COOH) derived from a polyhydric carboxylic acid. That is, the amorphous resin can be addition-polymerized with the above-mentioned styrene monomer and (meth)acrylic acid ester monomer, and a compound having a carboxyl group or a hydroxyl group (ampholyte compound) can be further polymerized. Preferably, it is a polymer consisting of:

Examples of the above amphoteric compounds include compounds having a carboxy group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester; 2-hydroxy Ethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate , compounds having a hydroxyl group such as polyethylene glycol mono(meth)acrylate;

The content of the structural unit derived from the amphoteric compound in the amorphous resin is preferably 0.5% by mass or more and 20% by mass or less.

The above-mentioned styrene acrylic resin can be synthesized by a method of polymerizing monomers using a known oil-soluble or water-soluble polymerization initiator. Examples of oil-soluble polymerization initiators include azo or diazo polymerization initiators, and peroxide polymerization initiators.

Examples of the azo or diazo polymerization initiators include 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis( cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile.

Examples of peroxide polymerization initiators include benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxy carbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, , 4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis-(4,4-t-butylperoxycyclohexyl)propane and tris-(t-butylperoxy)triazine.

Furthermore, when synthesizing resin particles of styrene acrylic resin by emulsion polymerization, a water-soluble radical polymerization initiator can be used as a polymerization initiator. Examples of water-soluble polymerization initiators include persulfates such as potassium persulfate and ammonium persulfate, azobisminodipropane acetate, azobiscyanovaleric acid and its salts, and hydrogen peroxide.

The weight average molecular weight (Mw) of the amorphous resin is preferably 5,000 or more and 150,000 or less, more preferably 10,000 or more and 70,000 or less, from the viewpoint of easily controlling the plasticity of the amorphous resin.

[Elastic modulus improver]
The toner of the present invention preferably contains an elastic modulus improver. Examples of such modulus improvers include aromatic hydrocarbon compounds such as terphenyl, organic acids such as abietic acid having a cyclic structure, and liquid paraffin. When such a compound is blended into toner particles containing the crystalline material according to the present invention, the storage modulus of the toner increases, and it is possible to suppress the external additive from being buried inside the toner particles.
Among these, it is preferable that the elastic modulus improver is liquid paraffin from the viewpoint of low-temperature fixability and long-term image stability. Further, liquid paraffin can increase the elastic modulus of the glass state of the toner without increasing the viscosity when the toner is melted.
The value of the mass ratio of the elastic modulus improver to the crystalline material is preferably within the range of 0.08 to 0.30, more preferably within the range of 0.10 to 0.25.

(liquid paraffin)
The "liquid paraffin" used in the present invention is a mixture of extremely pure liquid saturated hydrocarbons that belong to lubricating oil fractions in terms of boiling point, and is a chemically stable, inert, non-polar saturated hydrocarbon. be. Specifically, it is a paraffinic hydrocarbon, a naphthenic hydrocarbon, or an organic liquid mixture containing these as main components. Note that paraffinic hydrocarbons are aliphatic hydrocarbons with a molecular formula represented by C _n H _2n+2 , and have a linear structure or a branched structure, and naphthenic hydrocarbons are A cyclic saturated hydrocarbon represented by C _n H _2n , which usually has a cyclic structure with 5 to 6 carbon atoms. These are generally obtained from high-boiling fractions of petroleum through various refining steps, and are usually commercially available as a mixture of paraffinic hydrocarbons and naphthenic hydrocarbons.

Preferred physical properties of liquid paraffin include those having a kinematic viscosity of 4 to 200 mm ² /s at 40°C, or hydrocarbon compounds having a peak top molecular weight of 200 to 600 as measured by gel permeation chromatography (hereinafter abbreviated as GPC). It is. Particularly preferably, the peak top molecular weight in GPC measurement is 240 to 550. The kinematic viscosity at 40° C. is measured using a “B-type viscometer” (manufactured by Tokimec Co., Ltd.) in accordance with JIS K2283.

[Release agent]
As the mold release agent used in the present invention, known ones can be used. The mold release agent may be one type or more than one type. Examples of mold release agents include polyolefin waxes such as polyethylene wax and polypropylene wax, branched hydrocarbon waxes such as microcrystalline wax; long chain hydrocarbon waxes such as paraffin wax and Sasol wax; and distearyl. Dialkyl ketone wax such as ketone, carnauba wax, montan wax, behenate behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1, Included are ester waxes such as 18-octadecanediol distearate, tristearyl trimellitate, and distearyl maleate, and amide waxes such as ethylenediamine behenylamide and tristearyl trimellitate. The above-mentioned mold release agent is easily compatible with the vinyl resin. Therefore, due to the plasticizing effect of the release agent, the sharp melting properties of the toner can be enhanced and sufficient low-temperature fixability can be obtained. The above-mentioned mold release agent is preferably an ester wax (ester compound) from the viewpoint of obtaining sufficient low-temperature fixability, and furthermore, from the viewpoint of achieving both heat resistance and low-temperature fixability, a linear ester wax ( A linear ester compound) is more preferable.

The melting point T _mr of the above-mentioned mold release agent is preferably 60°C or higher, more preferably 65°C or higher, from the viewpoint of obtaining sufficient high-temperature storage stability. Further, the melting point T _mr of the release agent is preferably 90° C. or lower, and more preferably 75° C. or lower, from the viewpoint of obtaining sufficient low-temperature fixability of the toner. Further, the content of the release agent in the toner is preferably 1% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 20% by mass or less.

Note that the content of the release agent in the black toner described below is 55% higher than that in the chromatic toner from the viewpoint of achieving the aforementioned good relationship between the exothermic peak temperature of the black toner and the exothermic peak temperature of the chromatic toner. It is preferable that the amount is less by ~20% by mass.

[Other additives]
The toner base particles may further contain components other than the above-mentioned crystalline material, amorphous resin, and mold release agent, as long as the effects according to the present embodiment are achieved. For example, examples of the other components that the toner base particles may contain include a colorant and a charge control agent.

(colorant)
The above-mentioned coloring agent may be one kind or more than one kind. Examples of typical colorants include colorants for magenta, yellow, cyan, and black.

Examples of colorants for magenta include C. I. Pigment Red 2, 3, 5, 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, Includes 177, 178, 184, 202, 206, 207, 209, 222, 238, and 269.

Examples of colorants for yellow include C. I. Pigment Orange 31, Pigment Orange 43, C.I. I. Pigment Yellow 12, 14, 15, 17, 74, 83, 93, 94, 138, 155, 162, 180 and 185 are included.

Examples of colorants for cyan include C.I. I. Pigment Blue 2, 3, 15, 15:2, 15:3, 15:4, 16, 17, 60, 62, 66 and C. I. Contains Pigment Green 7.

Examples of colorants for black include carbon black and magnetic particles. Examples of carbon blacks include channel black, furnace black, acetylene black, thermal black and lamp black. Examples of magnetic particles include ferromagnetic metals such as iron, nickel, and cobalt; alloys containing these metals; compounds of ferromagnetic metals such as ferrite and magnetite; chromium dioxide; and ferromagnetic metals. Alloys that exhibit ferromagnetism by heat treatment are included. Examples of alloys that exhibit ferromagnetism upon heat treatment include Heusler alloys such as manganese-copper-aluminum and manganese-copper-tin.

The content of the colorant in the toner base particles can be determined appropriately and independently, and for example, from the viewpoint of ensuring color reproducibility of images, it should be 1% by mass or more and 30% by mass or less. is preferably 2% by mass or more and more preferably 20% by mass or less. In addition, the size of the particles of the colorant is preferably, for example, 10 nm or more and 1000 nm or less, more preferably 50 nm or more and 500 nm or less, and preferably 80 nm or more and 300 nm or less, in terms of volume average particle size. More preferred. The volume average particle size may be a catalog value, and for example, the volume average particle size (median diameter on a volume basis) of the colorant can be measured using "UPA-150" (manufactured by Microtrac Bell Co., Ltd.). can do.

(charge control goods)
Known charge control agents can be used as the charge control agent used in the present invention, examples include nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes and salicylic acid metal salts. The content of the charge control agent in the above toner is usually 0.1 parts by mass or more and 10 parts by mass or less, preferably 0.5 parts by mass or more and 5 parts by mass or less, based on 100 parts by mass of the binder resin. . The particle size of the charge control agent is, for example, 10 nm or more and 1000 nm or less, preferably 50 nm or more and 500 nm or less, and more preferably 80 nm or more and 300 nm or less in number average primary particle diameter.

<External additives>
The external additives used in the present invention may be one or more types. The external additive adheres to the surface of the toner base particles described above and improves the charging performance, fluidity, or cleaning performance of the toner. Examples of external additives include inorganic fine particles, organic fine particles, and lubricants.

Examples of inorganic compounds in the inorganic fine particles include silica, titania, alumina, and strontium titanate. The inorganic fine particles may be hydrophobized using a known silane coupling agent, silicone oil, or other surface treatment agent, if necessary. Further, the size of the inorganic fine particles is preferably 20 nm or more and 500 nm or less, and more preferably 70 nm or more and 300 nm or less in number average primary particle size.

As the organic fine particles, organic fine particles made of a homopolymer of styrene or methyl methacrylate or a copolymer thereof can be used. The size of the organic fine particles is about 10 to 2000 nm in number average primary particle diameter, and the particle shape is, for example, spherical.

The above-mentioned lubricant is used for the purpose of further improving cleaning properties and transfer properties. Examples of the above-mentioned lubricants include metal salts of higher fatty acids, more specifically salts of stearic acid such as zinc, aluminum, copper, magnesium, and calcium; oleic acid of zinc, manganese, iron, copper, and magnesium. salts of palmitic acid such as zinc, copper, magnesium, calcium, etc.; salts of linoleic acid such as zinc, calcium, etc.; salts of ricinoleic acid such as zinc, calcium, etc. The size of the lubricant is preferably 0.3 μm or more and 20 μm or less, more preferably 0.5 μm or more and 10 μm or less in volume-based median diameter (volume average particle size).

The volume-based median diameter of the lubricant can be determined according to JIS Z8825-1 (2013). Specifically, the details are as follows.

As the measuring device, a laser diffraction/scattering particle size distribution measuring device "LA-920" (manufactured by Horiba, Ltd.) is used. To set the measurement conditions and analyze the measurement data, use the dedicated software "HORIBA LA-920 for Windows (registered trademark) WET (LA-920) Ver. 2.02" that comes with the LA-920. Moreover, as a measurement solvent, ion-exchanged water from which impurity solids and the like have been removed in advance is used.

The measurement procedure is as follows (1) to (11).
(1) Attach the batch type cell holder to LA-920.
(2) Put a predetermined amount of ion-exchanged water into a batch type cell, and set the batch type cell in a batch type cell holder.
(3) Stir the inside of the batch type cell using a special stirrer chip.
(4) Press the "Refractive index" button on the "Display condition setting" screen and select the file "110A000I" (relative refractive index 1.10).
(5) On the "Display Condition Settings" screen, set the particle size standard to the volume standard.
(6) After performing warm-up operation for one hour or more, perform optical axis adjustment, optical axis fine adjustment, and blank measurement.

(7) Pour about 60 mL of ion exchange water into a 100 mL glass flat bottom beaker. In this, "Contaminon N" (a 10% by mass aqueous solution of a neutral detergent for cleaning precision measuring instruments with a pH of 7 consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, Wako Pure Chemical Industries, Ltd.) was added as a dispersant. Add approximately 0.3 mL of a diluted solution prepared by diluting (manufactured by the company) to approximately 3 times the mass with ion-exchanged water.

(8) Prepare an ultrasonic dispersion system "Ultrasonic Dispension System Tetora 150" (manufactured by Nikkaki Bios Co., Ltd.) that contains two oscillators with an oscillation frequency of 50 kHz with their phases shifted by 180 degrees and has an electrical output of 120 W. . Approximately 3.3 L of ion exchange water is placed in the water tank of the ultrasonic disperser, and approximately 2 mL of contaminon N is added to this water tank.

(9) Set the beaker of (7) above in the beaker fixing hole of the ultrasonic disperser, and operate the ultrasonic disperser. Then, the position of the beaker is adjusted so that the resonance state of the surface of the aqueous solution in the beaker is maximized.

(10) While the aqueous solution in the beaker of (9) above is irradiated with ultrasonic waves, about 1 mg of lubricant particles are added little by little to the aqueous solution in the beaker and dispersed. Then, the ultrasonic dispersion treatment is continued for another 60 seconds. At this time, the lubricant particles may form a lump and float on the liquid surface, but in that case, the beaker is shaken to submerge the lump in the water, and then ultrasonic dispersion is performed for 60 seconds. Further, in the ultrasonic dispersion, the water temperature in the water tank is adjusted as appropriate so that the water temperature is 10° C. or more and 40° C. or less.

(11) Immediately add the aqueous solution in which the lubricant particles prepared in (10) above are dispersed little by little to a batch type cell while being careful not to introduce air bubbles until the transmittance of light from the tungsten lamp reaches 90% or more. The concentration of the above dispersion liquid is adjusted so that it becomes 95%. Then, the particle size distribution is measured. A 50% cumulative diameter is determined based on the obtained volume-based particle size distribution data, and is taken as the volume-based median diameter of the lubricant.

The particle size of the external additive may be a catalog value or an actually measured value. The volume average particle diameter of the external additive was determined by observing 100 primary particles of the external additive on the toner base particles using a scanning electron microscope (SEM) device, and performing image analysis of the observed primary particles. The longest diameter and the shortest diameter for each external additive are measured, and the equivalent sphere diameter is determined from this intermediate value, and it can be determined as the diameter (D50v) at 50% of the cumulative frequency of the obtained equivalent sphere diameter. The volume average particle diameter of the external additive can be adjusted, for example, by pulverizing coarse particles, classifying them, or mixing classified particles.

The content of the external additive in the toner particles is preferably 0.1 parts by mass or more and 10.0 parts by mass or less based on 100 parts by mass of the toner particles. The above-mentioned external additives can be added to the toner base particles using various known mixing devices such as a turbular mixer, Henschel mixer, Nauta mixer, and V-type mixer.

<Carrier particles>
The carrier particles used in the present invention include magnetic particles. Examples of magnetic substances in the magnetic particles include conventionally known materials such as metals such as iron, ferrite, and magnetite; alloys of these metals with metals such as aluminum and lead. Among these, the magnetic particles are preferably ferrite particles.

The carrier particles may be resin-coated carrier particles having the above-mentioned magnetic particles and a resin layer covering the surface thereof, or magnetic substance-dispersed carrier particles in which fine particles of the above-mentioned magnetic material are dispersed in resin particles. It may be. Examples of resins for coating resin-coated carrier particles include olefin resins, cyclohexyl methacrylate-methyl methacrylate copolymers, styrene resins, styrene acrylic resins, silicone resins, ester resins, and fluororesins. Further, examples of the resin for forming the resin particles of the magnetic substance-dispersed carrier particles include acrylic resin, styrene acrylic resin, polyester, fluororesin, and phenol resin.

The size of the carrier particles is preferably 15 μm or more and 100 μm or less, more preferably 25 μm or more and 60 μm or less in volume average particle diameter. The content of carrier particles in the above toner is, for example, an amount such that the toner particle concentration is 6 to 8% by mass. Further, the volume average particle diameter of the carrier particles can be measured, for example, by the same method as the particle diameter of the external additive.

The average particle diameter of the above-mentioned toner particles is set to 3 in terms of volume average particle diameter, from the viewpoint of suppressing the occurrence of fixing offset due to the toner flying to the heating member during fixing, from the viewpoint of increasing transfer efficiency, and from the viewpoint of increasing toner fluidity. It is preferably .0 μm or more and 8.0 μm or less, and more preferably 4.0 μm or more and 7.5 μm or less. The average particle size of toner particles can be determined by measuring the volume average particle size using "Coulter Multisizer 3" (manufactured by Beckman Coulter), and can be determined by measuring the volume average particle size using "Coulter Multisizer 3" (manufactured by Beckman Coulter). It can be controlled by the concentration of the agent, the amount of the solvent added, the fusion time in the aggregation and fusion process, or the composition of the binder resin.

From the viewpoint of improving transfer efficiency, the average circularity of the toner particles is preferably 0.920 or more and 1.000 or less, and more preferably 0.940 or more and 0.995 or less. The above average circularity is expressed by the following formula. In the following formula, L0 represents the peripheral length (μm) of a projected image of the particle, and L1 represents the peripheral length (μm) of the circle determined from the equivalent circle diameter of the particle. The average circularity can be measured using, for example, an average circularity measuring device "FPIA-2100" (manufactured by Sysmex Corporation).
Average circularity = L1/L0

It is preferable that the toner base particles have a lamellar structure therein, from the viewpoint of facilitating the recrystallization of the crystalline resin and from the viewpoint of making it easy to achieve both low-temperature fixability and the other properties described above. For example, crystalline polyester greatly contributes to low-temperature fixability, but depending on the state of its presence in the toner, the effect of improving low-temperature fixability by the crystalline polyester may not be fully expressed. If the lamellar structure of the crystalline polyester exists in a desired position and size, melting of the binder resin is more effectively promoted starting from the lamellar structure, and low-temperature fixability is more effectively exhibited.

The above-mentioned lamellar structure is a lamellar crystal structure, and means a layered structure in which two or more layers of molecular chains of crystalline resin are laminated. FIG. 2A is an electron micrograph showing an example of a lamellar structure in the above toner. Examples of the lamellar structure include a layered structure produced by crystallization due to folding of molecular chains of a crystalline resin, and a layered structure produced by crystallization of molecular chains of a crystalline resin. The lamellar structure of crystalline polyester exists as an island phase having a closed interface (boundary between phases) in a domain portion of the lamellar structure, that is, a matrix that is a continuous phase.

Examples of molecular-level structures other than lamellar structures that can be adopted by crystalline resins include filamentous structures. The filamentous structure means a structure in which the molecular chains are not assembled to the extent that they form the layered structure. FIG. 2B is an electron micrograph showing an example of a thread-like structure in the toner. The ability of the filamentous structure to act as a starting point (initiator) when toner base particles start melting is lower than that of the lamellar structure.

The above-mentioned lamellar structure can be realized by, for example, the type of material (monomer) of the binder resin. For example, in the case of a styrene acrylic resin, it is possible to use a monomer with a structure similar to that of a crystalline material, such as 2-EHA, as a monomer for an amorphous resin, or to use dodecenyl succinic acid as a monomer for a crystalline polyester. This can be a powerful means of introducing

The presence or absence of a lamellar structure in toner base particles can be determined by, for example, examining a section (section thickness: 60 to 100 nm) of toner base particles stained with ruthenium tetroxide (RuO ₄ ) using a transmission electron microscope "JEM-2000FX" (JEOL Ltd.). This can be confirmed by observing the cross section using a model (manufactured by Co., Ltd.).

Further, the toner base particles preferably have a core-shell structure from the viewpoint of facilitating both heat resistance (for example, high-temperature storage stability) and low-temperature fixability.

The method for producing the toner particles is not limited, and examples include known polymerization methods such as suspension polymerization, emulsion polymerization aggregation, and dispersion polymerization. The toner particles may have a core-shell structure in which the surface of a core particle made of a core resin is covered with a shell layer made of a shell resin, or may have a single-layer structure without such a shell layer. particles may be used. In addition, in the case of particles having a core-shell structure, the shell resin constituting the shell layer is preferably an amorphous resin.

When a known external additive is added to toner base particles to form toner particles by a dry method of adding and mixing external additives, the external additive mixing device includes a turbular mixer, a Henschel mixer, a Nauta mixer, Various known mixing devices can be used, such as a V-type mixer.

《Toner manufacturing method》
Hereinafter, a specific example of the method for producing the above toner will be described in detail, taking as an example a method for producing a yellow toner when the crystalline material is crystalline polyester. Note that in the method for producing toners other than yellow toner, for example, magenta toner, cyan toner, and black toner, the method for producing yellow toner can be suitably employed by changing the colorant used. Note that the method for manufacturing the toner according to the present invention is not limited to the following.

<Preparation of aqueous dispersion of colorant fine particles>
By stirring and dissolving sodium dodecyl sulfate in ion-exchanged water, adding a yellow colorant to the resulting aqueous solution, and performing a dispersion treatment, an aqueous dispersion of colorant fine particles in which yellow colorant fine particles are dispersed is prepared. Ru.

<Preparation of aqueous dispersion of amorphous vinyl resin containing mold release agent>
(First polymerization)
Sodium dodecyl sulfate and ion-exchanged water are placed in a reaction vessel equipped with a stirring device, temperature sensor, cooling tube, and nitrogen introduction device, and heated while stirring under a nitrogen stream to dissolve potassium persulfate in the ion-exchanged water. For example, styrene (St) is added as a styrenic monomer, n-butyl acrylate (BA) as a (meth)acrylic acid ester monomer, a carboxy group [-COOH] or a hydroxy group [ A monomer mixture containing methacrylic acid (MAA) or the like as a compound having -OH] is added dropwise, and then polymerized by heating and stirring to prepare a dispersion (1) of resin particles.

(Second polymerization)
A solution of sodium polyoxyethylene (2) dodecyl ether sulfate dissolved in ion-exchanged water is charged into a reaction vessel equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen introduction device, and after heating, the above resin fine particles are dispersed. Liquid (1) and, for example, a compound having styrene (St) as a styrene monomer, n-butyl acrylate as a (meth)acrylate monomer, a carboxy group [-COOH] or a hydroxy group [-OH] A solution containing a monomer and a mold release agent, such as methacrylic acid (MAA), n-octyl-3-mercaptopropionate, and a mold release agent (behenate behenate (melting point 73°C)), was added. , and mix and disperse to prepare a dispersion containing emulsified particles (oil droplets).

Next, an aqueous initiator solution in which potassium persulfate is dissolved in ion-exchanged water is added to this dispersion, and the system is heated and stirred to perform polymerization, thereby preparing a dispersion (2) of resin particles.

(Third polymerization)
After adding ion-exchanged water to the dispersion (2) of resin fine particles and mixing well, an initiator aqueous solution in which potassium persulfate is dissolved in ion-exchanged water is added. , n-butyl acrylate (BA) as a (meth)acrylic acid ester monomer, methacrylic acid (MAA) as a compound having a carboxy group [-COOH] or a hydroxy group [-OH], n-octyl-3-mercaptopropylene. A monomer mixture consisting of pionate, etc. is added dropwise. After completion of the dropwise addition, polymerization is performed by heating and stirring, followed by cooling to prepare an aqueous dispersion of the amorphous vinyl resin containing a mold release agent.

<Preparation of aqueous dispersion of crystalline polyester>
(Synthesis of crystalline polyester)
Examples of raw material monomers and radical polymerization initiators for addition polymerization resin segments (herein referred to as styrene acrylic resin segments) include styrene, n-butyl acrylate, acrylic acid, and polymerization initiators (di-t-butyl peroxide). ) into the dropping funnel.

In addition, as raw material monomers for polycondensation resin segments (herein referred to as crystalline polyester segments), for example, sebacic acid, which is an aliphatic dicarboxylic acid, and 1,12-dodecanediol, which is an aliphatic diol, are added through a nitrogen inlet tube. , put into a four-necked flask equipped with a dehydration tube, a stirrer and a thermocouple, and heat to dissolve.

Next, under stirring, the raw material monomer and radical polymerization initiator for the addition polymerization resin segment placed in the dropping funnel were added dropwise to the heated and dissolved material solution for the polycondensation resin segment, and after aging, Unreacted addition polymerization monomers are removed under reduced pressure. Thereafter, an esterification catalyst is added, the temperature is raised, the reaction is carried out under normal pressure, and the reaction is further carried out under reduced pressure. After further cooling, a crystalline polyester, which is a hybrid resin, is obtained by reacting under reduced pressure.

(Preparation of aqueous dispersion of crystalline polyester)
The crystalline polyester obtained in the above synthesis example is dissolved in a solvent (for example, methyl ethyl ketone) while stirring. Next, an aqueous sodium hydroxide solution is added to this solution. An emulsion is prepared by adding water dropwise to the solution while stirring. Next, by distilling off the solvent from this emulsion, an aqueous dispersion in which the crystalline polyester is dispersed is prepared.

<Manufacture of yellow toner>
After putting an aqueous dispersion of an amorphous vinyl resin containing a mold release agent and ion exchange water into a reaction vessel equipped with a stirring device, a temperature sensor, and a cooling tube, an aqueous sodium hydroxide solution is added to adjust the pH.

Thereafter, an aqueous dispersion of colorant fine particles is charged into the reaction vessel, and then an aqueous magnesium chloride solution is added to prepare a mixed solution. The temperature of this mixed liquid is raised, and an aqueous dispersion of crystalline polyester is further added to the mixed liquid to advance aggregation. When the aggregated particles reach a desired particle size, an aqueous dispersion of amorphous polyester is added, and an aqueous solution of sodium chloride dissolved in ion-exchanged water is added to stop the growth of the particles. Thereafter, the mixture is heated and stirred to advance particle fusion. Then cool.

Next, the mixed liquid is subjected to solid-liquid separation, and the obtained solid content (toner base particles) is washed and then dried to obtain yellow toner base particles. Yellow toner particles are produced by adding external additives to the obtained toner base particles.

A yellow toner is produced by adding and mixing a known ferrite carrier to the yellow toner particles in an amount such that the toner concentration is 6% by mass or more and 8% by mass or less.

The above-mentioned toner is used in a known image forming method in electrophotography in a conventional manner. As described above, in addition to low-temperature fixability, the toner has excellent image stability with little fluctuation in the output image even when an image with a low printing rate is output for a long period of time.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto. In the examples, "parts" or "%" are used, but unless otherwise specified, "parts by mass" or "% by mass" are expressed.

[Example 1]
A colorant particle dispersion, a binder resin particle dispersion, and a crystalline polyester resin particle dispersion were prepared.

<Preparation of colorant particle dispersion>
While stirring a solution of 90 parts by mass of sodium dodecyl sulfate added to 1,600 parts by mass of ion-exchanged water, 420 parts by mass of "C.I. Pigment Blue 15:3" as a coloring agent was gradually added. A colorant particle dispersion liquid that develops a cyan color was prepared by dispersion treatment using a stirring device CLEARMIX (manufactured by M Technique Co., Ltd., "CLEARMIX" is a registered trademark of the same company). The colorant particles in the dispersion had a volume-based median diameter of 110 nm.

<Preparation of binder resin particle dispersion>
<Preparation of binder resin particle dispersion 1>
(1st stage polymerization)
4 parts by mass of sodium dodecyl sulfate and 3,000 parts by mass of ion-exchanged water were placed in a reaction vessel equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen gas introduction device, and while stirring at a stirring speed of 230 rpm under a nitrogen stream, the internal temperature was increased. was heated to 80°C. After raising the temperature, a solution of 10 parts by mass of potassium persulfate dissolved in 200 parts by mass of ion-exchanged water was added, the temperature was again raised to 80°C, and a mixed solution of the following monomers was added dropwise over 2 hours.

Styrene 570.0 parts by mass N-butyl acrylate 165.0 parts by mass Methacrylic acid 68.0 parts by mass After dropping the above mixture, polymerization was carried out by heating and stirring at 80°C for 2 hours, and resin particle dispersion ( 1-a) was prepared.

(Second stage polymerization)
A solution prepared by dissolving 3 parts by mass of sodium polyoxyethylene (2) dodecyl ether sulfate in 1210 parts by mass of ion-exchanged water was charged into a reaction vessel equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen introducing device and heated to 80°C. did. After heating, 60 parts by mass of the resin particle dispersion (1-a) prepared by the above first stage polymerization in terms of solid content, and the following monomers, chain transfer agent and mold release agent were dissolved at 80 ° C. The mixture was added.

Styrene (St) 245.0 parts by mass 2-ethylhexyl acrylate (2EHA) 97.0 parts by mass Methacrylic acid (MAA) 30.0 parts by mass Palmitic acid amide 100.0 parts by mass Liquid paraffin 1 25.0 parts by mass n-octyl -3-mercaptopropionate 4.0 parts by mass Behenate behenate (mold release agent, melting point 73°C) 100.0 parts by mass

Mixing and dispersion treatment was performed for 1 hour using a mechanical dispersion machine CLEARMIX (registered trademark) (manufactured by M Technique Co., Ltd.) having a circulation path to prepare a dispersion containing emulsified particles (oil droplets). A polymerization initiator solution prepared by dissolving 5.2 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water and 1000 parts by mass of ion-exchanged water were added to this dispersion, and the system was heated at 84°C for 1 hour. Polymerization was carried out by heating and stirring over a period of time to prepare a resin particle dispersion (1-b).

(Third stage polymerization)
A solution prepared by dissolving 7 parts by mass of potassium persulfate in 130 parts by mass of ion-exchanged water was added to the resin particle dispersion (1-b) obtained by the second stage polymerization. Furthermore, under a temperature condition of 82° C., a mixed solution of the following monomer and chain transfer agent was added dropwise over 1 hour.

Styrene (St) 400.0 parts by mass n-butyl acrylate (BA) 170.0 parts by mass Methacrylic acid (MAA) 35.0 parts by mass n-octyl-3-mercaptopropionate 8.0 parts by mass

After completion of the dropwise addition, polymerization was carried out by heating and stirring for 2 hours, followed by cooling to 28° C. to prepare Binder Resin Particle Dispersion 1. The binder resin particles in the dispersion had a volume-based median diameter of 145 nm. Further, the weight average molecular weight of the obtained binder resin was 35,000, and the glass transition temperature (Tg) was 37°C.

<Preparation of binder resin particle dispersions 2 to 18>
The method for producing binder resin particle dispersion 1 was repeated in the same manner as in the method for producing binder resin particle dispersion 1, except that the type and amount of fatty acid amide and the type and amount of liquid paraffin added during the second stage polymerization were changed as shown in Table I. Adhering resin particle dispersions 2 to 18 were obtained. In the table below, "-" indicates that the materials shown in the upper column were not used.
In addition, the following materials in Table I were used.

Palmitic acid amide: manufactured by Mitsubishi Chemical Corporation Stearic acid amide: manufactured by Tokyo Chemical Industry Co., Ltd. Behenic acid amide: manufactured by Tokyo Chemical Industry Co., Ltd. Liquid paraffin 1: Moresco White P-100, manufactured by MORESCO Corporation Liquid paraffin 2: Moresco White P-350P, manufactured by MORESCO Co., Ltd. Abietic acid: manufactured by Tokyo Chemical Industry Co., Ltd. m-terphenyl: manufactured by Tokyo Chemical Industry Co., Ltd.

<Preparation of crystalline polyester resin>
The following raw material monomers and radical polymerization initiator for the styrene acrylic polymerization segment were placed in a dropping funnel.

Styrene 36.0 parts by weight n-butyl acrylate 13.0 parts by weight Acrylic acid 2.0 parts by weight Radical polymerization initiator (di-t-butyl peroxide) 7.0 parts by weight The polymer was placed in a four-necked flask equipped with a nitrogen gas inlet tube, a dehydration tube, a stirrer, and a thermocouple, and heated to 170° C. to dissolve it.

Tetradecanedioic acid 440.0 parts by mass 1,4-butanediol 153.0 parts by mass Next, the raw material monomer for the styrene acrylic polymerization segment was added dropwise over 90 minutes while stirring, and after aging for 60 minutes, the pressure was reduced. The unreacted raw material monomer of the styrene acrylic polymerization segment was removed under pressure (8 kPa). Note that the amount of raw material monomer removed at this time was extremely small compared to the raw material monomer charged above. Thereafter, 0.8 parts by mass of titanium tetrabutoxide (Ti(O-n-Bu) ₄ ) was added as a catalyst, the temperature was raised to 235°C, and the temperature was raised to 235°C for 5 hours under normal pressure (101.3 kPa), and then under reduced pressure. (8 kPa) for 1 hour.

Subsequently, after cooling to 200° C., a crystalline polyester resin was obtained by reacting for 1 hour under reduced pressure (20 kPa). The crystalline polyester resin thus prepared was a hybrid resin (hybrid crystalline polyester) with a weight average molecular weight of 24,500 and a melting point of 76°C.

<Preparation of crystalline polyester resin particle dispersion>
100 parts by mass of crystalline polyester resin was dissolved in 400 parts by mass of ethyl acetate, and mixed with 638 parts by mass of a 0.26% by mass sodium dodecyl sulfate solution prepared in advance. While stirring the resulting mixed solution, ultrasonic dispersion treatment was performed for 30 minutes at a V-LEVEL of 300 μA using an ultrasonic homogenizer US-150T (manufactured by Nippon Seiki Seisakusho Co., Ltd.).

Thereafter, while heating to 40°C, ethyl acetate was completely removed while stirring under reduced pressure for 3 hours using a diaphragm vacuum pump V-700 (manufactured by BUCHI) to form a crystalline polyester resin particle dispersion. was prepared. The crystalline polyester resin particles in the dispersion had a volume-based median diameter of 160 nm.

《Manufacture of toner》
<Manufacture of toner 1>
In a reaction vessel equipped with a stirring device, a temperature sensor, and a cooling tube, 507 parts by mass (solid content equivalent) of the binder resin particle dispersion 1 prepared above and 32.5 parts by mass (solid content equivalent) of the colorant particle dispersion liquid were added. 500 parts by mass of ion-exchanged water was added, and the pH was adjusted to 10 by adding a 5 mol/L aqueous sodium hydroxide solution. Furthermore, a solution prepared by diluting 60.8 parts by mass of magnesium chloride hexahydrate with ion-exchanged water to 2 times was added at 30° C. over 10 minutes with stirring. After leaving for 3 minutes, the temperature was raised to 80° C. over 60 minutes.

After reaching 80°C, a solution prepared by diluting 10 parts by mass of magnesium chloride hexahydrate with ion-exchanged water to 2 times was added at 30°C over 10 minutes with stirring. The stirring speed was adjusted so that the particle size growth rate was 0.02 μm/min, and when the volume-based median diameter measured by Coulter Multisizer 3 (manufactured by Beckman Coulter) reached 5.8 μm, After adjusting the stirring speed to stop particle size growth and adding an aqueous solution in which 50.7 parts by mass of sodium chloride was dissolved in 250 parts by mass of ion-exchanged water, the mixture was stirred as it was and placed in a flow-type particle image analyzer "FPIA-". 3000'' (manufactured by Sysmex Corporation), and when the average circularity reached 0.970, the reaction liquid was cooled to 25° C. at a cooling rate of 10° C./min to obtain a dispersion of toner base particles 1.

The resulting dispersion was subjected to solid-liquid separation, the dehydrated toner cake was redispersed in 35° C. ion-exchanged water, and the solid-liquid separation operation was repeated three times for washing. After washing, toner base particles 1 (median diameter on a volume basis: 5.8 μm) were obtained by drying at 35° C. for 24 hours.

To 100 parts by mass of the obtained toner base particles 1, 0.6 parts by mass of hydrophobic silica particles (number average primary particle diameter: 12 nm, hydrophobicity degree: 68) and hydrophobic titanium oxide particles (number average primary particle diameter: 20 nm) were added. , hydrophobicity: 63) and 1.0 parts by mass of sol-gel silica (number average primary particle size: 110 nm, hydrophobicity: 63) were added, and mixed using a Henschel mixer (manufactured by Nippon Coke Industries Co., Ltd.). Mixing was carried out for 20 minutes at 32° C. at a rotor circumferential speed of 40 m/sec. After mixing, coarse particles were removed using a 45 μm mesh sieve to obtain Toner 1.

<Method for manufacturing toners 2, 3, and 18>
The manufacturing process was the same as that for toner 1, except that the binder resin particle dispersion 1 used was changed to binder resin particle dispersion 2, binder resin particle dispersion 3, and binder resin particle dispersion 18, respectively. Toner 2, Toner 3 and Toner 18 were obtained.

<Manufacture of toner 4>
In a reaction vessel equipped with a stirring device, a temperature sensor, and a cooling tube, 507 parts by mass (solid content equivalent) of the binder resin particle dispersion 4 prepared above and 32.5 parts by mass (solid content) of the colorant particle dispersion liquid were added. 500 parts by mass of ion-exchanged water was added, and the pH was adjusted to 10 by adding a 5 mol/L aqueous sodium hydroxide solution. Furthermore, a solution prepared by diluting 60.8 parts by mass of magnesium chloride hexahydrate with ion-exchanged water to 2 times was added at 30° C. over 10 minutes with stirring. After leaving for 3 minutes, the temperature was raised to 80° C. over 60 minutes.

After reaching 80°C, a solution prepared by diluting 10 parts by mass of magnesium chloride hexahydrate with ion-exchanged water was added over 10 minutes at 30°C with stirring, and after standing for 5 minutes, crystals were formed. A solution obtained by mixing 10 parts by mass (in terms of solid content) of dodecyl diphenyl ether disulfonic acid sodium salt with 44 parts by mass (in terms of solid content) of the polyester resin particle dispersion was added over 30 minutes. When the supernatant of the reaction solution became transparent, the stirring speed was adjusted so that the particle size growth rate was 0.02 μm/min, and the volume-based ratio measured using Coulter Multisizer 3 (manufactured by Beckman Coulter) was adjusted. When the median diameter reached 5.8 μm, the stirring speed was adjusted to stop particle size growth, and an aqueous solution of 50.7 parts by mass of sodium chloride dissolved in 250 parts by mass of ion-exchanged water was added.

Thereafter, the reaction solution was stirred as it was, and when the average circularity reached 0.970, the reaction solution was cooled to 25°C at a cooling rate of 10°C/min using a flow type particle image measuring device "FPIA-3000" (manufactured by Sysmex Corporation). The dispersion liquid of toner base particles 4 was obtained. The subsequent steps were carried out in the same manner as the manufacturing method of Toner 1 to obtain 4 Toner 4.

<Method for manufacturing toners 5 to 17>
Toners 5 to 17 were obtained in the same manner as toner 4 except that the type of binder resin particle dispersion and the amount of crystalline polyester resin particle dispersion were changed as shown in Table II below.

《Toner evaluation》
<Melting point of crystalline material>
The melting point of the crystalline material used in the production of the toner was determined by the method described above.

<Storage modulus>
The temperature at which the loss modulus reaches a maximum was defined as T _max , and the storage modulus at T _max was determined by the method described above.

<Image stability>
Using a commercially available color multifunction device "bizhub PRO C6500" (manufactured by Konica Minolta, Inc.), images were printed on A4-sized high-quality paper (65 g/m ² ) in a low-temperature, low-humidity environment (temperature 10°C, humidity 15% RH). As a test image, 100,000 sheets were printed to form a band-like solid image with a printing rate of 5%, and a gradation pattern with a gradation rate of 32 levels was output at the beginning of printing and after printing 100,000 sheets. The read values are subjected to Fourier transform processing that takes MTF (Modulation Transfer Function) correction into consideration, and the GI value (Graininess Index) is measured to match the human's specific luminous efficiency. Regarding the variation value Δ of the GI value after printing, the stability of the output image was evaluated according to the following evaluation criteria. The smaller the GI value, the better, and the smaller the GI value, the less grainy the image. Note that this GI value is a value published in the Journal of the Imaging Society of Japan 39(2), 84-93 (2000).

(Evaluation criteria)
◎: GI value variation value Δ is less than 0.02 between the initial printing stage and after printing 100,000 sheets (pass)
○: Fluctuation value Δ of GI value between initial printing and after printing 100,000 sheets is 0.02 or more and less than 0.04 (pass)
△: Change value Δ of GI value between initial printing and after printing 100,000 sheets is 0.04 or more and less than 0.06 (pass)
×: The variation value Δ of the GI value is 0.06 or more between the initial stage of printing and after printing 100,000 sheets (fail).

<Low temperature fixability>
The low-temperature fixing performance was evaluated using a commercially available multifunction machine "bizhub PRESS (registered trademark) C1070" (manufactured by Konica Minolta, Inc.). Developers were sequentially loaded into a device modified to allow the development of an A4 size NPI 128g/m ² (Nippon Paper A fixing experiment was conducted in which a solid image with a toner adhesion amount of 11.3 g/m ² was fixed on a toner (manufactured by Co., Ltd.), and the fixing temperature was repeatedly changed from 130° C. to 170° C. while increasing it in 2° C. increments. The fixing temperature at which under-offset does not occur was defined as the lower limit fixing temperature, and was used as an index of low-temperature fixing performance.

Note that the solid image with a toner adhesion amount of 11.3 g/m ² reproduces the output of a high adhesion amount image. Under-offset refers to an image defect in which the toner layer peels off from a transfer material such as a recording paper due to insufficient melting of the toner layer due to the heat applied when passing through a fixing device. The lower the fixing minimum temperature is, the better the fixing performance is.
Evaluation was made based on the following evaluation criteria. A score of △ or higher was considered to be a pass.

(Evaluation criteria)
◎: Below 146℃ ○: Over 146℃ and below 152℃ △: Over 152℃ and below 156℃ ×: Over 156℃

It can be seen that the toner of the present invention has excellent image stability with little fluctuation in the output image even when an image with low temperature fixability and low printing rate is output for a long period of time.

Claims (8)

A toner for developing an electrostatic latent image, comprising toner particles consisting of at least an amorphous resin (I), a crystalline material, a release agent, and an external additive,
The crystalline material is a hybrid crystalline polyester in which an amorphous resin (II) segment and a crystalline polyester segment are combined, or a fatty acid amide,
The melting point of the crystalline material is within the range of 70 to 120°C, and
An electrostatic latent material characterized in that the storage elastic modulus at T _max is within the range of 4.0×10 ⁸ to 1.0×10 ⁹ Pa, where T _max is the temperature at which the loss modulus reaches a maximum. Toner for image development. The toner for developing electrostatic latent images according to claim 1, characterized in that it contains terphenyl, abietic acid, or liquid paraffin. The toner for developing electrostatic latent images according to claim 1 or 2, wherein the storage elastic modulus at T _max is within a range of 5.0×10 ⁸ to 1.0×10 ⁹ Pa. . The toner for developing electrostatic latent images according to claim 1 or 2, wherein the storage elastic modulus at T _max is within a range of 6.0×10 ⁸ to 1.0×10 ⁹ Pa. . 5. The toner for developing electrostatic latent images according to claim 1, wherein the amorphous resin (II) segment is a styrene acrylic resin segment. The toner for developing an electrostatic latent image according to any one of claims 1 to 5, wherein the amorphous resin (I) contains an amorphous vinyl resin. The electrostatic latent material according to claim 2, characterized in that a mass ratio value of the terphenyl, the abietic acid, or the liquid paraffin to the crystalline material is within a range of 0.08 to 0.30. Toner for image development. An electrostatic latent image developing toner comprising toner particles consisting of at least an amorphous resin, a crystalline material, a release agent, and an external additive,
The crystalline material is a hybrid crystalline polyester in which a styrene acrylic resin segment and a crystalline polyester segment are combined,
The melting point of the crystalline material is within the range of 70 to 120°C,
The electrostatic latent image developing toner contains liquid paraffin,
The molecular weight of the liquid paraffin is within the range of 240 to 550, and
When the temperature at which the loss modulus reaches a maximum is T _max , the storage elastic modulus at T _max is within the range of 4.0×10 ⁸ to 1.0×10 ⁹ Pa. Toner for image development.