JP2017090829A - Toner for electrostatic latent image development and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic latent image development that is not easily scattered and has good adhesion during lamination, and a manufacturing method of the same.SOLUTION: A toner for electrostatic latent image development of the present invention is a toner for electrostatic latent image development comprising toner particles containing at least a binder resin and a mold release agent, wherein the toner particle contains an amorphous polyester resin and a crystalline resin as the binder resin, and contains the amorphous polyester resin as a main component of a resin contained in the toner particle; a domain of a connected crystalline structure in which the crystalline resin is in contact with the mold release agent and a domain of a filamentous crystalline structure of the crystalline resin present independent of the mold release agent are present in the toner particle; the filamentous crystalline structure has an average major axis in a range of 200 to 2000 nm on the cross section of the toner particle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrostatic latent image developing toner and a method for producing the same. More specifically, the present invention relates to a toner containing a crystalline resin, which has good low-temperature fixability, good fixing separation even when the fixing temperature is low, hardly disperses toner, and adhesion of the laminate. The present invention relates to an electrostatic latent image developing toner having good properties and a method for producing the same.

In recent years, electrophotographic image forming apparatuses have been increasingly demanded for higher speed, higher image quality, and wider application, and electrostatic latent image developing toner (hereinafter also simply referred to as “toner”) used therefor. Toners that can meet the demands of the market are being developed. For example, a toner corresponding to high image quality is required to have a sharp particle size distribution of toner particles. When the particle diameters of the toner particles are uniform and the particle size distribution is sharpened, the development behavior of each individual toner particle is uniformed, so that the reproducibility of minute dots is remarkably improved. However, it is not easy to sharpen the particle size distribution of toner particles by a conventional toner manufacturing method using a pulverization method.
On the other hand, an emulsion aggregation method has been proposed as a production method capable of arbitrarily controlling the shape and particle size distribution of toner particles. In this method, the colorant fine particle dispersion and, if necessary, the release agent fine particle dispersion are mixed with the emulsified dispersion of the binder resin particles. The toner particles are obtained by aggregating the particles and further fusing the particles by heating.

  Furthermore, from the viewpoint of global warming prevention measures, there is an increasing demand for energy saving for electrophotographic image forming apparatuses, and the development of low-temperature fixable toner that can be fixed with less energy is being promoted. Yes. As a typical study for lowering the fixing temperature of toner, one using a crystalline material can be cited. In addition, when pursuing low-temperature fixability, it is easy to melt with heat, and thus heat-resistant storage properties may be an issue. Therefore, development of a toner using an amorphous polyester resin as a main binder resin capable of achieving both low-temperature fixability and heat-resistant storage stability at a high level is underway.

  For example, in order to achieve sufficient low-temperature fixability, in a toner containing a crystalline polyester resin and an amorphous resin, the crystalline polyester resin constituting the toner base particles is included as a finely dispersed crystal structure, It has been proposed to achieve both low-temperature fixing and heat-resistant storage by adjusting the domain diameter (see, for example, Patent Document 1). Further, even when a crystalline resin is used, a toner having a structure in which the crystalline polyester resin and the release agent are in contact has been proposed in order to achieve excellent bending resistance and heat storage (for example, , See Patent Document 2).

However, the toners proposed by these prior arts have a problem in fixing and separating toner because the release agent (wax) hardly oozes out to the surface of the toner particles, particularly when the fixing temperature of the toner is lowered. Further, there is a problem in that the crystalline resin existing in the vicinity of the toner particle surface has a wide charge amount distribution and easily causes toner scattering.
When laminating after fixing the toner on the cardboard, the fixing temperature may be set high in order to fix the toner on the cardboard. When the fixing temperature is increased, the conventional toner containing a crystalline resin has a problem that the amount of the release agent oozes out and the adhesiveness of the laminate deteriorates.

Japanese Patent Laid-Open No. 2015-072456 JP 2008-33057 A

  The present invention has been made in view of the above-mentioned problems and circumstances, and the problem to be solved is that the low-temperature fixability is good, the fixing separation property is good even when the fixing temperature is lowered, the toner is not easily scattered, and To provide a toner for developing an electrostatic latent image having good adhesion of a laminate and a method for producing the same.

The inventors of the present invention, in an examination process to solve the above-mentioned problems, connected crystals in which a crystalline resin and a release agent are in contact with an amorphous resin mainly composed of an amorphous polyester resin of toner particles. The structure and the crystalline resin thread-like crystal structure that exists independently of the release agent are present, and the thread-like crystal structure has a predetermined average major axis, whereby the low-temperature fixability is good and the fixing temperature. It has been found that a toner for developing an electrostatic latent image can be provided that has a good fixing and separation property even when the thickness is low, hardly disperses the toner, and has a good adhesion of the laminate.
That is, the said subject which concerns on this invention is solved by the following means.

1. An electrostatic latent image developing toner comprising at least toner particles containing a binder resin and a release agent,
As the binder resin, containing an amorphous polyester resin and a crystalline resin,
Containing the amorphous polyester resin as a main component of the resin contained in the toner particles;
In the toner particles, there are a domain of a linked crystal structure in which the crystalline resin is in contact with the release agent, and a domain of a filamentous crystal structure of the crystalline resin that exists independently of the release agent. Exists and
An electrostatic latent image developing toner, wherein an average major axis of the thread crystal structure is in a range of 200 to 2000 nm in a cross section of the toner particles.

  2. 2. The electrostatic latent image developing toner according to item 1, wherein an average major axis of the thread crystal structure is in a range of 400 to 2000 nm in a cross section of the toner particles.

  3. 3. The electrostatic latent image developing toner according to item 1 or 2, wherein the crystalline resin contains a crystalline polyester resin.

  4). 4. The electrostatic latent image according to claim 1, wherein an average domain diameter of the connected crystal structure is in a range of 300 to 2500 nm in a cross section of the toner particle. Toner for image development.

5. In the cross section of the toner particle, the average ratio of the cross-sectional area of the connected crystal structure to the cross-sectional area of the toner particle is A, the average ratio of the cross-sectional area of the thread crystal structure is B, and independent of the crystalline resin. The average ratio of the cross-sectional area of the domain part of the release agent present in the above is defined as C, and the following formula (1) is satisfied. Toner for electrostatic latent image development.
Formula (1): 0.35 ≦ A / (A + B + C) ≦ 0.65

6). The metal concentration in the toner particles is in the range of 20 to 2000 ppm by mass;
The metal concentration is a concentration of a metal derived from at least one metal element selected from aluminum (Al), magnesium (Mg), and iron (Fe). The electrostatic latent image developing toner according to any one of the above.

  7). The toner for electrostatic latent image development according to any one of Items 1 to 6, wherein the toner particles have a core-shell structure in which a shell layer is coated on the surface of the core particles. .

  8). Any one of items 1 to 7, wherein the toner particles contain inorganic titanic acid compound fine particles having an average particle size in the range of 0.5 to 3.0 μm as an external additive. The toner for developing an electrostatic latent image according to the item.

  9. Item 9. The toner particle according to any one of Items 1 to 8, wherein the toner particles contain large-diameter silica fine particles having an average particle size in the range of 0.1 to 1.0 μm as an external additive. The electrostatic latent image developing toner according to 1.

10. A method for producing a toner for developing an electrostatic latent image according to any one of items 1 to 9,
By adding an aggregating agent to a dispersion liquid in which at least crystalline resin fine particles, amorphous resin fine particles and release agent fine particles are dispersed in an aqueous medium, these fine particles are aggregated to form aggregated particles. A process for producing a toner for developing an electrostatic latent image, comprising the step of:

According to the above-described means of the present invention, a toner for developing an electrostatic latent image having good low-temperature fixability, good fixing separation even at a low fixing temperature, hardly scattering toner, and good adhesion of a laminate. A manufacturing method thereof can be provided.
The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

The toner according to the present invention contains, in the toner particles, a linked crystal structure in which the crystalline resin is in contact with the release agent, and a thread-like crystal structure of the crystalline resin.
The filamentous crystalline structure of crystalline resin is an elongated crystalline structure and has a very large surface area, so it can be quickly dissolved into an amorphous polyester resin by heat, contributing to good low-temperature fixability of the toner. It is considered a thing.
In addition, when the toner particles contain a thread crystal structure of a crystalline resin, the thread crystal structure quickly dissolves in the amorphous polyester resin, so that the thread crystal structure is present in the portion where the thread crystal structure exists. Since a pseudo interface is formed, and the parting agent easily oozes out through this portion, it is considered that the fixing separation property is good even when the fixing temperature is lowered.

  In addition, the thread-like crystal structure of the crystalline resin can obtain the above-described effect when the average major axis is in the range of 200 to 2000 nm in the cross section of the toner particles. When the thickness is 200 nm or less, the continuity of the route is interrupted and the release agent is difficult to ooze out. When the thickness is 2000 nm or more, the uniformity when the filamentous crystal structure is melted is deteriorated. This is thought to be because the continuity is cut off and the release agent is difficult to ooze out.

  In addition, the crystalline resin thread-like crystal structure has a lower probability of the crystalline resin domain being present near the toner particle surface than when the small domains of the crystalline resin are finely dispersed. Is not widened, and it is considered that toner scattering hardly occurs.

  In addition, the linked crystal structure in which the crystalline resin is in contact with the release agent is obtained by melting the crystalline resin and the release agent at the same time even when the fixing temperature is set to a high temperature. It is considered that the viscosity of the toner increases, and exudation of excessive release agent can be suppressed. Here, in the case of laminating, the fixing temperature may be set high in order to fix the toner to the cardboard, but if the toner containing the linked crystal structure of the present invention is used, an excessive release agent may be used. Since exudation is suppressed, it is considered that the adhesion of the laminate is improved.

Schematic diagram showing an enlarged view of a cross section of a toner particle having a linked crystal structure and a thread crystal structure Schematic diagram showing a reference example of an enlarged view of a cross section of a toner particle having a lamellar crystal structure

  The electrostatic latent image developing toner of the present invention is an electrostatic latent image developing toner containing at least toner particles containing a binder resin and a release agent, and the amorphous resin is an amorphous polyester resin. And the crystalline resin, the amorphous polyester resin as a main component of the resin contained in the toner particles, and the crystalline resin is in contact with the release agent in the toner particles A domain of the linked crystal structure, and a domain of the thread-like crystal structure of the crystalline resin that exists independently of the release agent, and the thread-like crystal structure in a cross section of the toner particle The average major axis is in the range of 200 to 2000 nm. This feature is a technical feature common to the inventions according to claims 1 to 10.

  As an embodiment of the present invention, from the viewpoint of more effectively expressing the effects of the present invention, the average major axis of the thread crystal structure is preferably in the range of 400 to 2000 nm in the cross section of the toner particles.

  As an embodiment of the present invention, it is preferable to contain a crystalline polyester resin as the crystalline resin from the viewpoint of improving the low-temperature fixing property and the fixing separation property.

  As an embodiment of the present invention, from the viewpoint of more effectively expressing the effect of the present invention, the average domain diameter of the linked crystal structure is preferably in the range of 300 to 2500 nm in the cross section of the toner particle. .

  As an embodiment of the present invention, from the viewpoint of more effectively expressing the effects of the present invention, the average ratio of the cross-sectional area of the connected crystal structure to the cross-sectional area of the toner particle in the cross-section of the toner particle is A, When the average ratio of the cross-sectional area of the filamentous crystal structure is B, and the average ratio of the cross-sectional area of the domain part of the release agent present independently of the crystalline resin is C, 0.35 ≦ A / ( A + B + C) ≦ 0.65 is preferably satisfied.

  As an embodiment of the present invention, the metal concentration in the toner particles is in the range of 20 to 2000 ppm by mass from the viewpoint of improving the low temperature fixing property and the fixing separation property, and the metal concentration is aluminum (Al ), Magnesium (Mg), and iron (Fe), the concentration of the metal derived from at least one metal element is preferable.

  As an embodiment of the present invention, it is preferable that the toner particles have a core-shell structure in which a shell layer is coated on the core particle surface from the viewpoint of more effectively expressing the effects of the present invention.

  As an embodiment of the present invention, from the viewpoint of suppressing toner scattering, the toner particles may contain inorganic titanate compound fine particles having an average particle diameter in the range of 0.5 to 3.0 μm as an external additive. preferable.

  As an embodiment of the present invention, from the viewpoint of improving fixing separation property, the toner particles contain large-sized silica fine particles having an average particle diameter in the range of 0.1 to 1.0 μm as an external additive. Is preferred.

  From the viewpoint of satisfactorily forming toner particles of the toner for developing an electrostatic latent image of the present invention, a dispersion liquid in which at least crystalline resin fine particles, amorphous resin fine particles and release agent fine particles are dispersed in an aqueous medium. It is preferable to add a flocculant to agglomerate these fine particles to form agglomerated particles.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" showing a numerical range is used by the meaning containing the numerical value described before and behind that as a lower limit and an upper limit. In addition, unless otherwise specified, measurements such as operation and physical properties are values measured under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50% RH.

[Electrostatic latent image developing toner]
The electrostatic latent image developing toner (toner) of the present invention is an aggregate of toner particles.

<Toner particles>
The toner particles according to the present invention include at least a binder resin and a release agent, and the binder resin contains an amorphous resin and a crystalline resin. Further, the metal concentration in the toner particles is preferably within a predetermined range.
Further, the toner particles may further contain an internal additive such as a colorant and a charge control agent as necessary. The toner particles of the present invention are preferably toner particles to which an external additive has been added.
In the following description, the toner particles to which no external additive is added are also referred to as toner base particles.
In the present invention, “in the toner particles” means only inside the toner particles, that is, inside the toner base particles, and does not include an external additive.

<Existence state of domains in toner particles>
The toner of the present invention includes a domain of a linked crystal structure in which a crystalline resin is in contact with a release agent in a toner particle, and a domain of a filamentous crystal structure of a crystalline resin that exists independently of the release agent. Is present.
Here, the “domain” refers to a region in the continuous layer (matrix) of resin components constituting the toner particles and present in an isolated and dispersed manner in the form of threads, stripes or particles.

  As used herein, the term “linked crystal structure” refers to a crystal structure observed when a cross section of toner particles is observed by contacting a crystalline resin and a release agent in the cross section of the toner particles. That is, the crystalline resin and the release agent are collectively referred to as a linked crystal structure. Further, the domain diameter of the connected crystal structure is calculated by measuring a region surrounded by the outline of the region where the crystalline resin and the release agent are combined in the cross section of the toner particle.

The “thread-like crystal structure” as used in the present invention is not a so-called lamellar crystal structure in which the crystalline resin has a laminated structure in which the crystalline part and the amorphous part have a laminated structure. In the cross section of the toner particle, the average major axis of the crystal structure is at least 10 times the average minor axis.
The term “non-laminated type” as used herein refers to a structural type in which a clear laminated structure cannot be confirmed even when ruthenium staining is performed when a cross section of toner particles is observed.

For the toner particles according to the present invention, FIG. 1 shows a schematic diagram of an enlarged view of the cross section of the toner particles after ruthenium staining. The toner particles according to the present invention have a cross section of the toner particles, in the amorphous resin as the matrix 1, “domain 2 of the linked crystal structure in which the crystalline resin is in contact with the release agent” and “ The domain 3 ”of the filamentous crystal structure of the crystalline resin that exists independently of the release agent and the domain 4 of the release agent that exists independently of the crystalline resin exist. As a reference example, FIG. 2 shows “lamellar crystalline structure domain 5 of crystalline resin” which is a “laminated” crystalline structure.
The toner particles according to the present invention may include a lamellar crystal structure having a laminated structure, but the ratio of the cross-sectional area to the cross-sectional area of the toner particles is preferably less than 1%. More preferably, it is not present, that is, the cross-sectional area ratio is 0%.

<Linked crystal structure>
The shape of the crystalline resin forming the linked crystal structure in which the crystalline resin is in contact with the release agent is not particularly limited, but the average domain diameter of the linked crystal structure is 300 in the cross section of the toner particle. It is preferably in the range of ˜2500 nm, more preferably in the range of 300-2000 nm. If the average domain diameter of the linked crystal structure is small, the amount of the release agent oozing out tends to be small. Therefore, in order to ensure the amount of the release agent bleed, it is preferably 300 nm or more. Thereby, the effect of improving the fixing and separating property due to the presence of the thread crystal structure can be further exhibited. On the other hand, if the average domain diameter of the linked crystal structure is too large, the low-temperature fixability tends to be inhibited. Therefore, in order to ensure the low-temperature fixability, it is preferably 2500 nm or less, and more preferably 2000 nm or less. Is preferred.
The average domain diameter of the linked crystal structure can be controlled by, for example, the dispersed particle diameter of the release agent, the composition of the crystalline resin, the order of addition in the toner manufacturing process, and the like. For example, the average domain diameter of the linked crystal structure tends to be increased by increasing the dispersed particle diameter of the release agent or the crystalline resin, or by increasing the ratio of the previously added crystalline resin. Moreover, when the ratio of the release agent and crystalline resin added previously is the same, when the amount of the flocculant added in the process is increased, the average domain diameter of the linked crystal structure tends to increase.

<Filamentary crystal structure>
The filamentous crystal structure of the crystalline resin preferably has an average major axis in the range of 200 to 2000 nm and more preferably in the range of 400 to 2000 nm in the cross section of the toner particles. The effect is not clear, but is estimated as follows. When the crystalline resin filamentous crystal structure quickly dissolves in the amorphous resin, a pseudo interface is formed in the portion where the filamentous crystal structure was present, and the release agent is routed through that portion. It becomes easy to ooze out. When the average major axis of the filamentous crystal structure is 200 nm or less, the continuity of the crystalline resin portion is cut off, the release agent is hardly exuded, and the fixing separation property is lowered. On the other hand, if the thickness is 2000 nm or more, the melting rate of the crystalline resin thread-like crystal structure becomes non-uniform so that the continuity of the path is cut off, the release agent is hardly exuded, and the fixing separation property is lowered.
The average major axis of the thread crystal structure can be controlled by, for example, the amount and composition of the crystalline resin and the dispersion diameter of the crystalline resin in the crystalline resin dispersion. For example, when the addition amount of the crystalline resin is increased or the dispersion diameter of the crystalline resin in the crystalline resin dispersion is increased, the thread crystal structure tends to become larger. Furthermore, by cooling after the shape control and putting time while stirring, the crystal growth proceeds, and an elongated thread-like crystal structure can be obtained.
Further, when a crystalline resin having a structure not having a hybrid structure is used, there is a tendency that a filamentous crystal structure is more easily formed. Further, when the crystalline resin is a crystalline polyester, it is preferable that the acid and alcohol monomers have close carbon chain lengths because they are easily crystallized.

<Method for observing cross section of toner particles>
The cross section of the toner particles can be observed with a transmission electron microscope, an electron microscope, a scanning probe microscope (SPM), or the like. An example is given below, but the present invention is not limited to this as long as equivalent observations can be made.
(Observation conditions)
The cross section of the toner particles can be observed under the following observation conditions.
Apparatus: Electron microscope “JSM-7401F” (manufactured by JEOL Ltd.)
Sample: section of toner particles stained with ruthenium tetroxide (RuO ₄ ) (thickness of section: 60 to 100 nm)
Acceleration voltage: 30 kV
Magnification: 50000 times, bright field image

(Method for preparing a section of toner particles)
After 3 parts by weight of the prepared toner was added and dispersed in 35 parts by weight of a 0.2% aqueous solution of polyoxyethyl phenyl ether, the mixture was ultrasonically treated (Nippon Seiki Seisakusho, US-1200T) at 25 ° C. Processing is performed for a minute, and the external additive is removed from the toner surface to obtain toner particles for observation.
1 to 2 mg of the toner particles obtained above is put in a 10 mL sample bottle, dyed under the ruthenium tetroxide (RuO ₄ ) vapor dyeing conditions shown below, and then photocurable resin “D-800” (JEOL) In the company) and photocured to form blocks. Next, an ultrathin sample having a thickness of 60 to 100 nm is cut out from the above block using a microtome equipped with diamond teeth.

(Ruthenium tetroxide staining conditions)
Dyeing is performed using a vacuum electron staining apparatus VSC1R1 (manufactured by Philgen). In accordance with the apparatus procedure, a sublimation chamber containing ruthenium tetroxide was installed in the staining apparatus body, and after the prepared ultrathin section was introduced into the staining chamber, the staining conditions with ruthenium tetroxide were room temperature (24-25 ° C.), Staining is performed under conditions of a concentration of 3 (300 Pa) and a time of 10 minutes.

(Observation of crystal structure)
Within 24 hours after dyeing, observation is performed with a transmission electron detector using an electron microscope “JSM-7401F” (manufactured by JEOL Ltd.). Here, the domains in the toner particles can be discriminated by the difference in contrast stained with ruthenium tetroxide. Among the observed domains, the domain portion that is stained lighter is observed as the release agent domain, and the domain portion that is stained more densely is observed as the crystalline resin domain (filamentous crystal structure). When it is difficult to distinguish the degree of staining, a domain in which the average major axis of the crystal structure is at least 10 times the average minor axis is measured as a domain of the crystalline resin. Further, the average major axis and the average minor axis of the filamentous crystal structure are measured as follows.

<Measuring Method of Average Domain Diameter of Linked Crystal Structure, Average Long Diameter and Average Short Diameter of Filament Crystal Structure>
The average domain diameter of the linked crystal structure and the average long diameter and average short diameter of the filamentous crystal structure can be calculated using, for example, commercially available image processing software for an image observed by the above method.
The domain diameter of the connected crystal structure in the cross section of the toner particle is calculated by the horizontal maximum chord length (CORD H). Specifically, a photographic image obtained by photographing a cross section of toner base particles produced in the same manner as described above is taken in by a scanner, and the horizontal direction of the connected crystal structure is measured using an image processing analyzer LUZEX AP (manufactured by Nireco Corporation). Determine the maximum chord length (CORD H).
In addition, the major axis and minor axis of the filamentous crystal structure are obtained by observing a photographic image observed in the same manner as described above by using an image processing analysis apparatus LUZEX AP (manufactured by Nireco Corporation). LNG), the minor axis (minor axis) is calculated using the width (BR'DTH).
The average domain diameter of the linked crystal structure, and the average major axis and the average minor axis of the thread crystal structure were measured for both the coupled crystal structure and the thread crystal structure out of 100 toner particles. Calculated as the arithmetic average value of things.
The cross section of the toner particles used in these measurements is observed by selecting a cross section of the toner particles that is ± 10% (for example, 5.8 μm ± 0.58 μm) of the volume average particle diameter of the toner particles.

  Further, when the cross section of 100 toner particles is observed by the above method, it is sufficient that 60% (60 particles) or more of the toner particles satisfying the average major axis of the thread crystal structure exist in the cross section. 80% (80 or more) are preferably present. If the toner particles satisfying the above-mentioned regulations are 60% or more of the whole, the effects of low-temperature fixability, improved separability, suppression of toner scattering, and adhesion of the laminate can be obtained. In the present invention, the crystalline resin may include a structure other than the thread crystal structure, for example, a lamellar crystal structure, but in order to obtain the effects of the present invention, the crystalline resin has a structure other than the thread crystal structure. The crystalline resin is preferably less than 1% in cross-sectional area ratio.

<Average cross-sectional area ratio of domains in toner particles>
In the cross section of the toner particle, the average ratio of the cross-sectional area of the connected crystal structure to the cross-sectional area of the toner particle is A, the average ratio of the cross-sectional area of the filamentous crystal structure is B, and the mold release is present independently of the crystalline resin. When the average ratio of the cross-sectional area of the domain part of the agent is C, it is preferable to satisfy the following formula (1).
Formula (1): 0.35 ≦ A / (A + B + C) ≦ 0.65
When the value of “A / (A + B + C)” exceeds 0.65, the compatibility rate between the crystalline resin and the binder resin becomes slow, the low-temperature fixability is deteriorated, and the wax is difficult to ooze and the separability is improved. There is a tendency to get worse. On the other hand, if it is less than 0.35, excessive release of the release agent tends to occur, and the adhesiveness of the laminate tends to deteriorate when the fixing temperature is raised.

(Measuring method)
The cross-sectional area of the domain part of the connected crystal structure, the thread-like crystal structure, and the release agent in the cross section of the toner particle is obtained by observing the cross section of the toner particle as an image processing analyzer LUZEX AP (manufactured by Nireco Corporation). The “area AREA” is used for measurement. The cross-sectional area is calculated by measuring a region surrounded by the outer contour.
Further, the average ratio of the respective cross-sectional areas is calculated from an arithmetic average value by observing 100 toner particles.
The cross section of the toner particles used in the measurement is observed by selecting a cross section of the toner particles that is ± 10% (for example, 5.8 μm ± 0.58 μm) of the volume average particle diameter of the toner particles.

<Form of toner particles>
The toner particles may have a so-called single layer structure, or may have a core-shell structure (a form in which a resin that forms a shell layer on the surface of the core particles is aggregated and fused). Good. The resin particles having a core / shell structure have a resin region (shell layer) on the surface of resin particles (core particles) containing a colorant, a release agent and the like.
The core / shell structure is not limited to a structure in which the shell layer completely covers the core particles. For example, the shell layer does not completely cover the core particles, and the core particles are exposed in some places. Including those that are.
The cross-sectional structure of the core-shell structure can be confirmed using a known means such as a transmission electron microscope (TEM) or a scanning probe microscope (SPM).

<Average circularity of toner particles>
In the toner according to the present invention, the individual toner particles constituting the toner preferably have an average circularity of 0.920 to 1.000 from the viewpoint of stability of charging characteristics and low-temperature fixability. More preferably, it is from 950 to 0.995. When the average circularity is within the above range, the individual toner particles are less likely to be crushed, the contamination of the frictional charge imparting member is suppressed, the toner chargeability is stabilized, and the image quality of the formed image is high. It will be a thing. The average circularity of the toner is a value measured using “FPIA-2100” (manufactured by Sysmex). Specifically, the measurement sample (toner) was blended with an aqueous solution containing a surfactant, dispersed by performing ultrasonic dispersion for 1 minute, and then subjected to measurement conditions HPF by “FPIA-2100” (manufactured by Sysmex). In the (high magnification imaging) mode, photographing is performed at an appropriate density with an HPF detection number of 3000 to 10000, the circularity is calculated according to the following formula for each toner particle, the circularity of each toner particle is added, and all toners are added. It is a value calculated by dividing by the number of particles. If the number of HPF detections is in the above range, reproducibility can be obtained.

Toner particle circularity = (perimeter of a circle having the same projected area as the particle image) / (perimeter of the particle projection image)
<Toner particle size>
The volume-based median diameter (volume average particle diameter) of the toner particles according to the present invention is preferably 3 to 10 μm, more preferably 4 to 8 μm. By using toner particles within this range, reproducibility of fine lines and high image quality of photographic images can be achieved, and toner consumption can be reduced as compared with the case where toner particles having a large particle diameter are used. be able to. Also, toner fluidity can be secured. The volume average particle size of the toner particles can be controlled by the concentration of the aggregating agent, the amount of the solvent added in the agglomeration / fusion process during the production of the toner particles described later, the fusing time, and the composition of the resin component. it can. The volume-based median diameter of the toner can be measured by, for example, “Multisizer 3” (manufactured by Beckman Coulter, Inc.).

<Metal concentration in toner particles>
The metal concentration in the toner particles according to the present invention is preferably in the range of 20 to 2000 mass ppm. This is because the metal element-derived metal ions contained in the toner particles are cross-linked by ionic bonds between the crystalline resin and the amorphous resin, and the crystalline resin thread crystal structure is incorporated in the toner particles. It is assumed that it can exist stably. Therefore, the effect of low-temperature fixability due to the inclusion of the crystalline resin thread crystal structure can be expressed more effectively, and the effect that the fixing separation property is good even when the fixing temperature is lowered can be obtained. Can do. In addition, when the metal concentration is higher than 20 ppm by mass, the effect of improving the fixing separation can be obtained. When the metal concentration is lower than 2000 ppm by mass, the low-temperature fixing property is not increased without excessively increasing the amount of crosslinking due to ionic bonds. A sufficient effect can be obtained.

  The metal concentration is preferably a metal concentration derived from at least one metal element selected from aluminum (Al), magnesium (Mg), and iron (Fe). Further, from the viewpoint of coloring, aluminum (Al) and magnesium (Mg) are more preferable. These metal elements are preferably metal elements derived from an aggregating agent used in toner production.

  As the flocculant, for example, a water-soluble metal salt having a divalent or trivalent metal element can be used. Specific examples include magnesium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, and the like. And trivalent metal salts such as aluminum chloride, aluminum sulfate, ferric chloride, and ferric sulfate. These metal salts can be used singly or in combination of two or more.

(Measuring method of metal concentration)
The amount of the metal element present in the toner particles is not particularly limited as long as a minute amount can be determined, but can be determined by acid decomposition / inductively coupled plasma emission spectrometry. An example of measurement is shown below.

(1. Pre-processing)
100 mg of toner particles are decomposed with sulfuric acid and nitric acid in a sealed microwave decomposition apparatus “ETHOS1 manufactured by Milestone General Co., Ltd.”. If there are any undegraded products, elute the target components using hydrochloric acid, hydrofluoric acid, hydrogen peroxide, etc. The decomposition solution is appropriately diluted with ultrapure water.

(2. Measurement)
Measurement is performed using a high-frequency inductively coupled plasma optical emission spectrometer (ICP-OES, manufactured by Hitachi High-Tech Science Corporation, SPS3520UV). The wavelength is not limited to the following as long as it has no interference and high sensitivity. For example, Al can be measured at 167.079 nm, Mg can be measured at 279.553 nm, and Fe can be measured at 259.940 nm. A calibration curve is prepared by adding a standard solution for atomic absorption of each element to a decomposition solution not containing a sample so that the acid concentration is the same as that of the sample solution.
Hereinafter, each constituent component such as a crystalline resin, an amorphous resin, and a release agent constituting the toner of the present invention will be described.

<Crystalline resin>
The crystalline resin forming the thread crystal structure is not particularly limited as long as it is a resin having crystallinity, and conventionally known crystalline resins in this technical field can be used. Specific examples thereof include a crystalline polyester resin, a crystalline polyurethane resin, a crystalline polyurea resin, a crystalline polyamide resin, and a crystalline polyether resin. Crystalline resins can be used singly or in combination of two or more. Among these, it is preferable to use a crystalline polyester resin from the viewpoint of improving the low-temperature fixability.

  Here, the “crystalline polyester resin” is obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a derivative thereof and a divalent or higher alcohol (polyhydric alcohol) and a derivative thereof. Among known polyester resins, in differential scanning calorimetry (DSC), it refers to a resin having a clear endothermic peak rather than a stepwise endothermic change. The clear endothermic peak specifically means a peak in which the half-value width of the endothermic peak is within 15 ° C. when measured at a rate of temperature increase of 10 ° C./min in differential scanning calorimetry (DSC). To do.

  Examples of the polyvalent carboxylic acid derivatives include alkyl esters, acid anhydrides, and acid chlorides of polyvalent carboxylic acids, and examples of the polyhydric alcohol derivatives include ester compounds of polyhydric alcohols and hydroxycarboxylic acids.

  The polyvalent carboxylic acid is a compound containing two or more carboxy groups in one molecule. Of these, divalent carboxylic acids are compounds containing two carboxy groups in one molecule, such as oxalic acid, malonic acid, succinic acid, adipic acid, pimelic acid, sebacic acid, azelaic acid, n-dodecyl. Succinic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid Saturated aliphatic dicarboxylic acids such as acids; cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, itaconic acid; phthalic acid, isophthalic acid, terephthalic acid, etc. Aromatic dicarboxylic acids can be mentioned. Examples of polyvalent carboxylic acids other than divalent carboxylic acids include trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid. Examples of the derivative of the polyvalent carboxylic acid include anhydrides of these carboxylic acid compounds or alkyl esters having 1 to 3 carbon atoms. These may be used individually by 1 type and may be used in combination of 2 or more type.

  A polyhydric alcohol is a compound containing two or more hydroxy groups in one molecule. Among these, divalent polyols (diols) are compounds containing two hydroxy groups in one molecule, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butane. Diol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol And aliphatic diols such as neopentyl glycol and 1,4-butenediol. Examples of polyols other than divalent polyols include trihydric or higher polyhydric alcohols such as glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These may be used individually by 1 type and may be used in combination of 2 or more type.

  In addition, the polycondensable monomer may have partial branching or crosslinking depending on selection of the carboxylic acid valence and alcohol valence.

The crystalline resin of the present invention may be a crystalline resin having a hybrid structure (hybrid resin). However, from the viewpoint of facilitating the formation of a thread crystal structure, the crystalline resin having no hybrid structure may be used. preferable.
Here, the crystalline resin having a hybrid structure is a resin in which a “crystalline resin segment” and a “resin segment other than the crystalline resin” are chemically bonded. The “crystalline resin segment” indicates a portion derived from a crystalline resin, and the “resin segment other than the crystalline resin” indicates a portion derived from a resin other than the crystalline resin. Examples of the resin other than the crystalline resin include vinyl resins such as styrene acrylic resins, urethane resins, urea resins, and polyester resins having no crystallinity. As the resin unit other than the crystalline resin, one type may be used alone, or two or more types may be combined.

  The melting point (Tm) of the crystalline resin is preferably 55 to 90 ° C, more preferably 65 to 85 ° C. If the melting point of the crystalline resin is within the range of 55 to 90 ° C., sufficient low-temperature fixability and excellent hot offset resistance can be obtained. The melting point of the crystalline resin can be controlled by the resin composition and molecular weight.

  The melting point of the crystalline resin can be measured with a differential calorimeter (DSC). For example, “Diamond DSC” (manufactured by Perkin Elmer) can be used. As a measurement procedure, 3.0 mg of toner is sealed in an aluminum pan and set in a holder. For the measurement of the reference, an empty aluminum pan was used, the first temperature raising process in which the temperature was raised from 0 ° C. to 200 ° C. at a temperature raising rate of 10 ° C./min, from 200 ° C. to 0 ° C. at a cooling rate of 10 ° C./min. Data is acquired by measurement conditions (temperature increase / cooling conditions) that pass through the cooling process for cooling and the second temperature increasing process for increasing the temperature from 0 ° C. to 200 ° C. at a temperature increase rate of 10 ° C./min. Based on the DSC curve obtained by this measurement, the temperature at the peak top of the endothermic peak derived from the crystalline resin in the second temperature raising process is defined as the melting point.

  The content of the crystalline resin is preferably in the range of 1 to 45% by mass and more preferably in the range of 5 to 45% by mass with respect to the total amount of the resin contained in the toner particles. When the amount of the crystalline resin is 1% by mass or more, the effect of low-temperature fixability can be exhibited, and when it is 5% by mass or more, the effect tends to be further increased. In addition, if the amount of the crystalline resin increases too much, the amount of the amorphous polyester resin decreases relatively, so the low-temperature fixability and the heat-resistant storage property cannot be compatible at a high level, and the heat-resistant storage property of the toner tends to deteriorate. Is preferably 45% by mass or less.

Note that the content of the crystalline resin referred to here excludes the content of the hybrid resin chemically bonded to the crystalline resin segment when the crystalline resin has a hybrid structure.
Further, the “total amount of resin contained in the toner particles” in the present invention means the total amount of resin components contained in the toner particles, and does not include the above-described internal additives and external additives.

  The method for forming the crystalline polyester resin is not particularly limited, and the resin may be formed by polycondensation (esterification) of the polyvalent carboxylic acid and the polyhydric alcohol using a known esterification catalyst. it can. Details of the manufacturing method will be described later.

<Amorphous resin>
As the amorphous resin, an amorphous polyester resin is contained as a main component of the resin contained in the toner particles. Here, “the main component of the resin contained in the toner particles” means containing in the range of 50 to 99 mass% with respect to the total amount of the resin contained in the toner particles. Moreover, it contains within the range of 50-99%, It is more preferable to contain within the range of 50-95 mass%, It is more preferable to contain at 65-95 mass%. When the amount of the amorphous polyester resin is 50% by mass or more with respect to the total amount of the resin contained in the toner particles, both low-temperature fixability and heat-resistant storage stability can be achieved at a high level, and 65% by mass or more. And the effect tends to increase. In addition, if the content of the amorphous polyester resin is excessively increased, the amount of the crystalline resin is relatively decreased and the effect of improving the low-temperature fixability is weakened. Therefore, the total amount of the resin contained in the toner particles is reduced. It is 99 mass% or less, and it is preferable that it is 95 mass% or less.

  The amorphous polyester resin is not particularly limited as long as it has an amorphous property, and a known amorphous polyester resin can also be used. Here, the “amorphous polyester resin” refers to a polyester resin that does not have an endothermic peak due to a change in the endothermic amount in differential scanning calorimetry (DSC).

  There is no restriction | limiting in particular as a manufacturing method of the amorphous polyester resin used by this invention, It can manufacture with the general polymerization method of polyester which makes aromatic dicarboxylic acid and a polyhydric alcohol react. Further, the amorphous polyester resin may be one kind of amorphous polyester resin, but may be a mixture of two or more kinds of amorphous polyester resins.

The acid component constituting the amorphous polyester resin is preferably an aromatic dicarboxylic acid, such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconic acid, Examples thereof include dimethyl isophthalate, fumaric acid, dodecenyl succinic acid and the like. Among these, dimethyl isophthalate, terephthalic acid, dodecenyl succinic acid, and trimellitic acid are preferable.
As the alcohol component constituting the amorphous polyester resin, a polyhydric alcohol is preferable. For example, as a divalent or trivalent alcohol, ethylene glycol, propylene glycol, 1,4-butanediol, 2,3-butanediol, Diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, ethylene oxide adduct of bisphenol A, Examples thereof include a propylene oxide adduct of bisphenol A, glycerin, sorbitol, 1,4-sorbitan, trimethylolpropane and the like. Among these, an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A are preferable.

  As an amorphous resin, you may contain vinyl-type resin etc. as resin components other than the amorphous polyester-type resin mentioned above.

<Release agent (wax)>
Examples of the release agent contained in the toner particles according to the present invention include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene; silicones that exhibit a softening point upon heating; oleic acid amide, erucic acid amide, ricinoleic acid amide, stearin Fatty acid amides such as acid amides; plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax and jojoba oil; animal waxes such as beeswax; carbonization such as paraffin wax, microcrystalline wax and Fischer-Tropsch wax Hydrogen waxes, stearyl stearate, behenyl behenate, butyl stearate, propyl oleate, monostearic glyceride, glyceryl distearate, pentaerythritol tetrabehenate, diethylene Recall monostearate, dipropylene glycol distearate, distearate diglycerides, may be mentioned sorbitan monostearate, ester waxes such as cholesteryl stearate and the like. These can be used alone or in combination of two or more. From the viewpoint of obtaining low-temperature fixability and releasability, it is preferable to use one having a melting point of 50 to 95 ° C.

The content of the release agent is preferably in the range of 2 to 20% by mass with respect to the total amount of resin contained in the toner particles.
Moreover, it is particularly preferable to use monoester waxes as a release agent from the viewpoint of facilitating formation of the crystalline resin filamentous crystal structure according to the present invention. This is because the release agent and the crystalline resin according to the present invention are likely to exist independently due to the balance of the affinity between the release agent and the crystalline resin or amorphous resin in the toner particles. It is believed that there is.

<Colorant>
The toner particles according to the present invention may contain a colorant. Examples of the colorant include carbon black, black iron oxide, dye, and pigment.

  Examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. Examples of black iron oxide include magnetite, hematite, and iron iron trioxide.

  Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 and the like.

  Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 48: 3, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 150, 166, 177, 178, 222, 238, 269, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment yellow 14, 17, 74, 93, 94, 138, 155, 156, 158, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, and the like.

  The colorant for obtaining the toner of each color can be used singly or in combination of two or more for each color. The content ratio of the colorant in the toner particles is preferably 1 to 10% by mass.

<Charge control agent>
The toner particles according to the present invention may contain a charge control agent. Examples of charge control agents include metal complexes of salicylic acid derivatives with zinc or aluminum (salicylic acid metal complexes), calixarene compounds, organic boron compounds, and fluorine-containing quaternary ammonium salt compounds.

  The content of the charge control agent is usually preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the resin component in the toner.

<External additive>
To the toner particles according to the present invention, fine particles such as known inorganic fine particles and organic fine particles, lubricants and the like are added as external additives on the surface from the viewpoint of improving the charging performance, fluidity, and cleaning properties of the toner. It is preferable to do. Various external additives may be used in combination.
Examples of the fine particles added as the external additive include inorganic oxide fine particles such as silica fine particles, alumina fine particles and titania fine particles, inorganic stearate compound fine particles such as aluminum stearate fine particles and zinc stearate fine particles, or strontium titanate. Inorganic titanate compound fine particles such as fine particles and zinc titanate fine particles can be mentioned.

  Among these external additives, it is preferable to add large-diameter silica fine particles having an average particle diameter of 0.1 to 1.0 μm to the toner base particles. By setting the particle diameter of the large-diameter silica fine particles to 0.1 μm or more, a hard component can be present on the surface in contact with the fixing member, and fixing separation property can be improved. Further, when the particle diameter of the large silica fine particles is 1.0 μm or less, it is easy to adhere to the toner particles, and the effect of the external additive can be obtained.

  Further, among these external additives, it is preferable to add titanic acid compound fine particles such as fine particles having an average particle diameter in the range of 0.5 to 3.0 μm to the toner base particles. By setting the particle diameter of the titanate compound fine particles to 0.5 μm or more, the positively chargeable titanate compound fine particles act like a pseudo carrier, so that the charge amount distribution can be narrowed and toner scattering can be suppressed. it can. In addition, when the particle diameter of the titanate compound fine particles is 3.0 μm or less, transfer defects due to excessively low resistance of the positively chargeable titanate compound fine particles can be prevented.

As a lubricant, a salt of zinc stearate, aluminum, copper, magnesium, calcium, etc., a salt of zinc oleate, manganese, iron, copper, magnesium, etc., a salt of zinc palmitate, copper, magnesium, calcium, etc., Examples thereof include metal salts of higher fatty acids such as zinc linoleic acid, salts such as calcium, and zinc ricinoleic acid, such as zinc and calcium.
These external additives may be subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil, or the like from the viewpoint of heat-resistant storage stability and environmental stability.

  The amount of these external additives added is preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the toner base particles.

[Method for producing toner for developing electrostatic latent image]
Examples of the method for producing toner particles include a pulverization method, a suspension polymerization method, a miniemulsion method, an emulsion aggregation method, and other known methods. Examples of the method for producing the toner particles of the present invention include: Is preferably an emulsion aggregation method.

  The method for producing a toner of the present invention is a method for producing a toner comprising toner particles containing at least a binder resin and a release agent and, if necessary, toner constituents such as a colorant and a charge control agent. Then, by adding an aggregating agent to a dispersion liquid in which at least crystalline resin fine particles, amorphous resin fine particles and release agent fine particles are dispersed in an aqueous medium, these fine particles are aggregated to form aggregated particles. It is a method which has the process of forming.

  Here, as a method for producing toner particles according to the present invention, a dispersion of crystalline resin fine particles and a dispersion of amorphous resin fine particles are prepared separately, and a flocculant containing a metal salt is used. Aggregation is desirable. By controlling the particle diameter of the crystalline resin fine particles in the dispersion, the domain diameter of the crystalline resin fine particles in the amorphous resin can be controlled, and the crystalline resin thread-like crystal structure according to the present invention Can be formed. Furthermore, after the toner base particles are formed, the temperature is increased again after cooling, and the long axis diameter of the crystalline resin filamentous crystal structure can be controlled by appropriately giving a time for sufficient crystallization.

  The above-described method for producing the toner of the present invention will be described with reference to an example. For example, when obtaining toner particles containing a colorant, a crystalline resin, an amorphous resin and a release agent as toner constituents, the toner can be produced by a production method including the following steps.

(1) Step of preparing a dispersion of colorant fine particles (2) Step of preparing a dispersion of crystalline resin fine particles (3) Step of preparing a dispersion of amorphous resin fine particles (4) Release agent fine particles Step (5) of preparing a dispersion liquid By adding a flocculant to a dispersion liquid in which colorant fine particles, crystalline resin fine particles, amorphous resin fine particles and release agent fine particles are dispersed in an aqueous medium, Core particle forming step for forming core particles (6) If necessary, shell resin fine particles are added to an aqueous medium in which the core particles are dispersed to aggregate and fuse the shell resin fine particles on the surface of the core particles. A shell forming step for forming toner particles having a core-shell structure (7) an aging step for controlling the shape of the aggregated particles by aging the aggregated particles by thermal energy (8) cooling if necessary Later crystalline tree (9) Filtration / washing step (10) for separating toner particles from the toner particle dispersion system and removing flocculant, aggregation terminator, surfactant, etc. from the toner particles. Drying step of drying washed toner particles (11) Step of adding external additive to dried toner particles In the following description, the steps (5) to (8) are the toner base It is also called a particle formation process.

<(1) Step of Preparing Colorant Fine Particle Dispersion>
A dispersion of colorant fine particles can be prepared by dispersing a colorant in an aqueous medium. The colorant dispersion treatment is preferably performed in a state where the surfactant concentration in the aqueous medium is not less than the critical micelle concentration (CMC) since the colorant is uniformly dispersed. Various known dispersers can be used as a disperser used for the dispersion treatment of the colorant. The dispersion diameter of the colorant fine particles in the dispersion prepared in the step of preparing the colorant fine particle dispersion is preferably in the range of 10 to 300 nm in terms of volume-based median diameter. The volume-based median diameter of the colorant fine particles in this colorant fine particle dispersion can be measured by a dynamic light scattering method using, for example, “Microtrack UPA-150” (manufactured by Nikkiso Co., Ltd.).

<(2) Step of preparing a dispersion of crystalline resin fine particles>
This step is preferably configured to include the following steps.
(A-1) Crystalline polyester resin synthesis step (A-2) Crystalline polyester resin solution preparation step (A-3) Solvent removal step

(A-1) Crystalline polyester resin synthesis step The method for producing the crystalline polyester resin is not particularly limited, and can be produced by a general polyester polymerization method in which a polyvalent carboxylic acid and a polyhydric alcohol are reacted. For example, direct polycondensation, transesterification, etc. are used separately depending on the type of monomer. Catalysts that can be used in the production of the crystalline polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; zinc, manganese, antimony, titanium, tin, zirconium, germanium, etc. Metal compounds; phosphorous acid compounds, phosphoric acid compounds, amine compounds, and the like. Specific examples include the following compounds. For example, sodium acetate, sodium carbonate, lithium acetate, lithium carbonate, calcium acetate, calcium stearate, magnesium acetate, zinc acetate, zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium tetraethoxide, titanium Tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, antimony trioxide, triphenylantimony, tributylantimony, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium tetrabutoxide, Zirconium naphthenate, zirconyl carbonate, zirconyl acetate, zirconyl stearate, zirconyl octylate, germanium oxide, trifer Ruhosufaito, tris (2, 4-t-butylphenyl) phosphite, ethyltriphenylphosphonium bromide, triethylamine, compounds such as triphenyl amine.

(A-2) Crystalline polyester resin solution preparation step The crystalline polyester resin synthesized as described above is dissolved in an organic solvent to prepare a crystalline polyester resin solution. Thereafter, the crystalline polyester solution is emulsified and dispersed in an aqueous medium to form oil droplets made of the crystalline polyester solution. In this process, oil prepared by the phase inversion emulsification method can be used to uniformly disperse the oil droplets by changing the stability of the carboxy group of the polyester. It is excellent in that it is not dispersed. In the “phase inversion emulsification method”, a resin is dissolved in an organic solvent to obtain a resin solution, a neutralization step in which a neutralizer is added to the resin solution, and the neutralized resin solution is dispersed in an aqueous system. By passing through an emulsification step of emulsifying and dispersing in a medium to obtain a resin emulsion, and a desolvation step of removing the organic solvent from the resin emulsion, a dispersion of resin fine particles is obtained. The particle size of the resin fine particles in the dispersion can be controlled by changing the amount of neutralizing agent added. There is a tendency that the smaller the neutralizer addition amount, that is, the lower the neutralization degree, the larger the particle size of the resin fine particles in the dispersion.

(Organic solvent)
The organic solvent only needs to dissolve the crystalline polyester resin, and ethyl acetate, methyl ethyl ketone, toluene and the like can be preferably used.

(Aqueous medium)
In the present embodiment, the “aqueous medium” refers to a medium composed of 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. It is preferable to use an alcohol-based organic solvent that does not dissolve the resin. In addition, amine or ammonia may be dissolved in the aqueous medium as necessary.

(Surfactant)
In the above aqueous medium, a surfactant such as a normal cationic surfactant, an anionic surfactant, an amphoteric surfactant, and a nonionic surfactant may be dissolved as necessary. As the surfactant, it is preferable to use an anionic surfactant because it is excellent in dispersion stability of oil droplets by the crystalline polyester resin, and stability against temperature change is obtained. Examples of the anionic surfactant include higher fatty acid salts such as sodium oleate; alkyl aryl sulfonates such as sodium dodecylbenzene sulfonate; alkyl sulfate salts such as sodium lauryl sulfate; polyoxyethylene lauryl ether sodium sulfate; Polyoxyethylene alkyl ether sulfates such as sodium polyethoxyethylene lauryl sulfate; polyoxyethylene alkyl aryl ether sulfates such as sodium polyoxyethylene nonylphenyl ether; sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, poly Alkyl sulfosuccinic acid ester salts such as sodium oxyethylene lauryl sulfosuccinate and derivatives thereof Etc. can be mentioned. The above surfactants can be used singly or in combination of two or more as desired.

(A-3) Solvent removal step By removing the organic solvent from the oil droplets formed in the step (A-2), fine particles of the crystalline polyester resin are produced, and a dispersion of the crystalline polyester resin fine particles is obtained. Prepared. Specifically, the organic solvent is preferably distilled off in a state where the degree of vacuum is in the range of 400 to 50000 Pa and at a temperature in the range of 30 to 50 ° C.

The particle size of the crystalline polyester resin particles is preferably in the range of 30 to 500 nm, for example, in terms of volume-based median diameter. The particle size of the crystalline polyester resin fine particles can be measured by a dynamic light scattering method using, for example, “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).
It is preferable that the weight average molecular weight measured by the gel permeation chromatography (GPC) of crystalline polyester resin exists in the range of 5000-100000, More preferably, it exists in the range of 10000-50000. When the molecular weight is 5000 or more, compatibility with the amorphous polyester resin is suppressed, and deterioration of heat resistance is suppressed. When it is 100,000 or less, deterioration of low-temperature fixability can be suppressed.

<(3) Step of preparing a dispersion of amorphous resin fine particles>
This step is preferably configured to include the following steps.

(B-1) Amorphous polyester resin synthesis step (B-2) Amorphous polyester resin solution preparation step (B-3) Solvent removal step

  The specific synthesis, preparation and solvent removal steps from (B-1) to (B-3) are the same as the steps from (A-1) to (A-3) in the crystalline polyester dispersion preparation step. It will be omitted because it conforms.

  As for the particle diameter of the fine particles of the amorphous polyester resin, the volume-based median diameter is preferably in the range of 50 to 300 nm. The particle diameter of the fine particles of the amorphous polyester resin is measured by a dynamic light scattering method using, for example, “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).

  The weight average molecular weight of the amorphous polyester resin measured by gel permeation chromatography (GPC) is preferably in the range of 5,000 to 100,000, more preferably in the range of 5,000 to 50,000. When the molecular weight is 5000 or more, deterioration of heat resistant storage stability can be suppressed. When it is 100,000 or less, deterioration of low-temperature fixability can be suppressed.

<(4) Step of preparing a dispersion of release agent fine particles>
The release agent fine particle dispersion is prepared by dispersing the release agent in the form of fine particles in an aqueous medium.
The aqueous medium is as described in the above-mentioned section of “2. Preparation of dispersion of crystalline resin fine particles”. In this aqueous medium, a surfactant or resin is used for the purpose of improving dispersion stability. Fine particles or the like may be added.

  Dispersion of the release agent fine particles can be performed using mechanical energy, and such a disperser is not particularly limited, and examples thereof include a high-pressure homogenizer, a rotary shearing homogenizer, and an ultrasonic dispersion. A general dispersion method such as a machine, a high-pressure impact disperser, a ball mill having media, a sand mill, or a dyno mill can be used, and is not limited at all.

  The content of the release agent fine particles in the release agent fine particle dispersion is preferably in the range of 10 to 50% by mass, and more preferably in the range of 15 to 40% by mass. Within such a range, effects of preventing hot offset and ensuring separability can be obtained.

<(5-8) Toner base particle forming step>
In the toner base particle forming step, the crystalline resin fine particles (crystalline polyester resin fine particles), the amorphous resin fine particles (amorphous polyester resin fine particles), the release agent fine particles and the colorant fine particles are charged as necessary. It is also possible to agglomerate particles of other toner components such as a control agent.

  Here, the crystal structure in the toner particles according to the present invention can be controlled by the order of addition of the dispersions of various materials and the divided addition. Specifically, first, a part of the dispersion liquid of the crystalline resin fine particles and a part of the dispersion liquid of the release agent fine particles are aggregated with the flocculant, and then the dispersion liquid of the amorphous resin fine particles is added. Then, the remaining dispersion of the crystalline resin fine particles and the dispersion of the release agent fine particles are added and agglomerated with an aggregating agent to finally form toner base particles. At this time, the previously added crystalline resin fine particles and the release agent fine particles form a linked crystal structure, and the later added crystalline resin fine particles and the release agent fine particles exist in a state that does not form a linked crystal structure. I guess the probability will be higher. Here, the crystalline resin fine particles added later form a thread-like crystal structure in the domain, and depending on the structure of the added crystalline resin, the dispersed particle size, and the crystal growth process described later, The average major axis can be controlled.

As a specific method for aggregating and fusing the crystalline polyester resin fine particles, the amorphous polyester resin fine particles, the release agent fine particles, and the colorant fine particles, an aggregating agent is added to an aqueous medium so as to have a critical aggregation concentration or more. Then, by heating to a temperature not lower than the glass transition point of the resin particles and not higher than the melting peak temperature of the mixture, crystalline polyester resin fine particles, amorphous polyester resin fine particles, release agent fine particles and coloring At the same time as the salting-out of particles such as agent fine particles proceeds, the fusion is proceeded in parallel, and when the particles grow to the desired particle size, the particle growth is stopped by adding a coagulation terminator or adjusting the pH. In addition, heating is continued in order to control the particle shape as necessary.
In this method, the time allowed to stand after adding the flocculant is shortened as quickly as possible, and immediately heated to a temperature above the glass transition point of these resin particles and below the melting peak temperature of these mixtures. Is preferred. The reason for this is not clear, but depending on the standing time after salting out, the aggregation state of the particles may fluctuate and the particle size distribution may become unstable, and the surface properties of the fused particles may vary. This is because there is concern about the occurrence. The time until this temperature rise is usually preferably within 30 minutes, and more preferably within 10 minutes. Moreover, it is preferable that it is 1 degree-C / min or more as a temperature increase rate. The upper limit of the heating rate is not particularly specified, but is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to rapid progress of fusion.

Furthermore, after the reaction system reaches a temperature equal to or higher than the glass transition point, it is important to continue the fusion by maintaining the temperature of the reaction system for a certain time. Thereby, the growth and fusion of the toner base particles can be effectively advanced, and the durability of the finally obtained toner particles can be improved. In the present invention, it is preferable to add shell-forming resin particles in the aggregation / fusion step, and to agglomerate / fuse the shell-layer formation resin on the surface of the single-layered particles (core particles). Specifically, the dispersion of the core particles is added to the dispersion of the shell resin particles while maintaining the temperature in the core particle formation process, and the shell resin particles are slowly aggregated on the surface of the core particles while continuing the heating and stirring. Then, the shell layer is coated by fusing to form toner particles. At that time, the temperature is slowly increased while adjusting the pH so that the aggregation of the shell resin fine particles does not occur. Thereby, toner particles having a core-shell structure are obtained. In this case, following the shelling step, the reaction system is further heat-treated until the shell layer forming resin is further agglomerated and fused to the surface of the core particles and the shape of the particles becomes a desired shape. good. This heat treatment may be performed until the average circularity of the toner particles having a core / shell structure falls within the range of the average circularity. The core-shell structure is not limited to a structure in which the shell layer completely covers the core particles. For example, the shell layer does not completely cover the core particles, and the core particles are exposed in some places. Including.
The particle size of the toner base particles obtained in this toner base particle forming step is, for example, preferably such that the volume-based median diameter (D50% diameter) is in the range of 2 to 9 μm, more preferably in the range of 4 to 7 μm. Is within. The volume-based median diameter of the toner base particles can be measured by, for example, a “particle size distribution measuring device Multisizer 3” (manufactured by Beckman Coulter, Inc.).

(Aggregation process)
The agglomeration step described above is performed by using a compound containing a divalent or trivalent metal element in a dispersion liquid in which colorant fine particles, amorphous resin fine particles, crystalline resin fine particles, and release agent fine particles are dispersed in an aqueous medium. This is a step of aggregating these fine particles to form aggregated particles by adding an aggregating agent. In this aggregating step, the binder resin fine particles constituting the agglomerated particles may be fused by heating at or above the glass transition point of the binder resin throughout the whole or appropriately.

As the flocculant, a compound having a divalent or trivalent metal element is used. Examples of such a flocculant include a water-soluble metal salt having a divalent or trivalent metal element or a hydrate thereof, polysilica iron, polyaluminum chloride, and the like. Examples of the water-soluble metal salt having a divalent or trivalent metal element include divalent metal salts such as magnesium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate; aluminum chloride, aluminum sulfate, etc. And trivalent metal salts. These flocculants can be used individually by 1 type or in combination of 2 or more types. As the flocculant, it is preferable that the divalent or trivalent metal element is Mg or Al from the viewpoint of particle size controllability at the time of aggregation. The addition amount of the flocculant is preferably 1 to 500 mmol, more preferably 2 to 200 mmol, with respect to 1 L of the aqueous medium in the dispersion. In the aggregating step, the temperature of the dispersion liquid when adding the aggregating agent is not particularly limited, but is preferably equal to or lower than the glass transition point of the binder resin.
These aggregating agents are presumed to be ion-bonded to a plurality of carboxy groups at the end of the polyester resin and metal-crosslinked. Therefore, a metal crosslink is formed between the emulsified particles of the crystalline polyester resin and the emulsified particles of the amorphous polyester resin, and the portion forms a rigid structure to some extent even when heat is applied. It is presumed that the domain of the crystalline polyester resin in the crystalline polyester resin can be retained, and that the path of the release agent can be assisted.
The content of metal ions derived from the flocculant in the toner particles is preferably in the range of 20 to 2000 ppm by mass. This can be quantified using an ICP emission analyzer. When the amount is less than 20 ppm by mass, the effect of improving the fixing separation property is reduced, and when it is more than 2000 ppm by mass, the effect of the low temperature fixing property by the crosslinked structure is reduced.

(Cooling process)
After the toner base particles have a desired average circularity, the dispersion is cooled. At this time, by controlling the cooling conditions, the existence state (for example, the domain diameter and shape of each material, the existence position, etc.) of the material constituting each toner base particle in the toner particle changes. Decreasing the cooling rate can, for example, promote crystal growth of the crystallized material. On the other hand, when the cooling rate is increased, for example, the crystallization of the crystallization substance does not promote and the structure in the aging process tends to be maintained. In the present invention, it is preferable to slow the cooling rate for the purpose of promoting crystal growth.

(Crystal growth process)
In the present invention, if necessary, a crystal growth step for promoting crystallization of the crystalline resin after cooling can be included. By including this crystallization growth step, it is possible to give sufficient time for the crystalline resin to crystallize, and to grow the filamentous crystal structure of the crystalline resin into a more elongated shape.
The crystal growth process is a process in which the molecular folding structure is rearranged and maintained at a temperature below the melting point of the crystalline resin to improve the crystallinity, and the temperature is 10 ° C. or more lower than the melting point of the crystalline resin. It is desirable to hold at. Furthermore, it is preferable to hold at a temperature lower by 20 ° C. or more.

<(9) Filtration / washing process, (10) Drying process>
The filtration / washing step and the drying step can be performed by employing various known methods. That is, after aging to the desired average circularity in the aging step and cooling, solid-liquid separation and washing are performed by a known method such as a centrifugal separator, and the organic solvent is removed by drying under reduced pressure. Then, moisture and a small amount of organic solvent are removed by a known drying apparatus such as a flash jet dryer and a fluidized bed drying apparatus. The drying temperature may be in a range where the toner base particles are not fused.

<(11) Step of adding external additive>
The step of adding the external additive is a step of preparing toner particles by adding and mixing the external additive as necessary to the dried toner base particles. The toner base particles prepared through the steps up to the drying step can be used as toner particles as they are, but are known on the surface from the viewpoint of improving the charging performance, fluidity, or cleaning properties as a toner. It is preferable to add particles such as inorganic fine particles and organic fine particles and a lubricant as external additives.
Various external additives may be used in combination. Examples of the inorganic fine particles include inorganic oxide fine particles such as silica fine particles, alumina fine particles and titanium oxide fine particles, inorganic stearate compound fine particles such as aluminum stearate fine particles and zinc stearate fine particles, or strontium titanate and zinc titanate. And inorganic titanic acid compound fine particles. These inorganic fine particles are preferably those subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil, or the like from the viewpoint of heat-resistant storage stability and environmental stability.
In the present invention, it is preferable to use a plurality of external additives in combination, and it is also preferable to use strontium titanate having an average particle diameter of 500 nm to 3 μm and silica having an average particle diameter of 100 nm to 1 μm in combination. Is more preferable from the viewpoint of achieving both high performance and toner scattering at a high level.
The amount of these external additives added is in the range of 0.05 to 5 parts by mass, preferably in the range of 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner base particles. Examples of the method for adding the external additive include a dry method in which the external additive is added in powder form to the dried toner base particles. Examples of the mixing device include mechanical mixing devices such as a Henschel mixer and a coffee mill. It is done.

[Developer for electrostatic latent image development]
The toner of the present invention can be used as a magnetic or nonmagnetic one-component developer, but may be mixed with a carrier and used as a two-component developer. When the toner is used as a two-component developer, the carrier includes magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead. In particular, ferrite particles are preferable. Further, as the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a dispersion type carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used.

  The volume-based median diameter of the carrier is preferably 20 to 100 μm, and more preferably 25 to 80 μm. The volume-based median diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympathic) equipped with a wet disperser.

[Electrophotographic image forming method]
The electrostatic latent image developing toner and developer according to the present invention can be used in various known electrophotographic image forming methods. For example, it can be used in a monochrome image forming method or a full color image forming method. In the full-color image forming method, four types of color developing devices for yellow, magenta, cyan, and black, and one electrostatic latent image carrier (also referred to as “electrophotographic photosensitive member” or simply “photosensitive member”) Any image, such as a four-cycle image forming method comprising: a color developing device for each color and an image forming unit having an electrostatic latent image carrier for each color. A formation method can also be used.

  As an electrophotographic image forming method, specifically, using the developer for developing an electrostatic latent image according to the present invention, for example, charging on an electrostatic latent image carrier with a charging device (charging process), By developing an electrostatic latent image (exposure process) electrostatically formed by image exposure by charging toner with a carrier in the developer for developing an electrostatic latent image according to the present invention in a developing device. A toner image is obtained by developing the image (development process). Then, the toner image is transferred to a recording medium (transfer process), and then the toner image transferred onto the recording medium is fixed on the recording medium by a contact heating type fixing process (fixing process). can get.

  The recording medium (also referred to as media, recording material, recording paper, recording paper, etc.) may be a commonly used one, and is not particularly limited as long as it retains a toner image. Specifically, for example, plain paper from thin paper to thick paper, fine paper, art paper, rough paper, coated paper such as coated paper, commercially available Japanese paper or postcard paper, OHP plastic film, cloth, Examples include soft transparent films and synthetic paper such as YUPO paper.

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.

<Synthesis of crystalline resin (crystalline polyester resin)>
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introducing device, 258.0 parts by mass of polycarboxylic acid: octanedioic acid (molecular weight 174.2) and polyhydric alcohol: 1,8-octanediol (Molecular weight 146.2) 192.0 parts by mass were charged. Dibutyltin oxide 0.7 mass part and hydroquinone 0.4 mass part were added as a catalyst, and it was made to react at 170 degreeC under nitrogen gas atmosphere for 5 hours. Furthermore, it was made to react at 170 degreeC until resin of desired melting | fusing point was obtained at 3.3 kPa, and crystalline resin (C1) was obtained. When this crystalline resin (C1) was measured by DSC at a temperature elevation rate of 10 ° C./min, it had a clear peak, the peak top temperature was 70 ° C., and the weight average molecular weight was 15000.
A crystalline resin C2 was prepared in the same manner as the synthesis method of the crystalline resin C1, except that the types and addition amounts of the polyvalent carboxylic acid and the polyhydric alcohol were changed as shown in “Table 1”. Table 1 also shows the melting point (° C.) and the weight average molecular weight (Mw).

<Preparation of aqueous dispersion of crystalline resin fine particles (crystalline polyester resin fine particles)>
300 parts by mass of the crystalline resin (C1) was melted and transferred in the molten state to the emulsification disperser “Cabitron CD1010” (manufactured by Eurotech Co., Ltd.) at a transfer rate of 100 parts by mass. Simultaneously with the transfer of the crystalline resin (C1) in the molten state, dilute ammonia water having a concentration of 0.37% by mass obtained by diluting the reagent ammonia water with ion-exchanged water in the aqueous solvent tank is supplied to the emulsifier / disperser. The sample was transferred at a transfer rate of 0.1 liter per minute while being heated to 100 ° C. with a heat exchanger. Then, the emulsification disperser was operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² to prepare a crystalline resin fine particle dispersion (CA-1). Note that dilute aqueous ammonia was added so that the degree of neutralization was 59%. The dispersed particle diameter of the crystalline resin fine particles in the crystalline resin part particle dispersion (CA-1) was 101.0 nm in terms of volume-based median diameter.
The crystalline resin fine particle dispersion (CA) is the same as the above crystalline resin fine particle dispersion (CA-1) except that the type and neutralization degree of the crystalline resin are changed as shown in “Table 2” below. -2 to CA-5) were produced. Table 2 shows the crystalline resin type, neutralization degree, and dispersed particle size of each dispersion.

The degree of neutralization is calculated by converting the amount of ammonia water used for neutralization into the mass (g) of potassium hydroxide (KOH) used for neutralization, (%).
Degree of neutralization (%) = [(KOH amount used for neutralization [g]) / (KOH amount [g] capable of neutralizing 100% of crystalline resin (crystalline polyester resin) end)] × 100

<Synthesis of Amorphous Resin (Amorphous Polyester Resin)>
112 parts by mass of terephthalic acid (TPA), 6 parts by mass of trimellitic acid (TMA), 12 parts by mass of fumaric acid (FA), 60 parts by mass of adipic acid, 290 parts by mass of bisphenol A propylene oxide adduct (BPA · PO), bisphenol A 55 parts by weight of ethylene oxide adduct (BPA · EO) was placed in a reaction vessel equipped with a stirrer, thermometer, cooling tube, and nitrogen gas introduction tube, and the inside of the reaction vessel was replaced with dry nitrogen gas. 0.1 parts by mass of the side was added, and a polymerization reaction was performed for 9 hours while stirring at 180 ° C. under a nitrogen gas stream. Further, 0.2 parts by mass of titanium tetrabutoxide is added, the temperature is raised to 220 ° C., and the polymerization reaction is carried out for 6 hours while stirring, and then the pressure in the reaction vessel is reduced to 1333.2 Pa and the reaction is performed under reduced pressure. As a result, an amorphous resin (A1) was obtained.
This amorphous resin (A1) had a glass transition point (Tg) of 53 ° C. and a weight average molecular weight (Mw) of 25,000.

<Preparation of Aqueous Dispersion of Amorphous Resin Fine Particles (Amorphous Polyester Resin Fine Particles)>
An aqueous solution in which 200 parts by mass of the amorphous resin (A1) is dissolved in 200 parts by mass of ethyl acetate and then dissolved in 800 parts by mass of ion-exchanged water so that the concentration of sodium polyoxyethylene lauryl ether sulfate is 1.3% by mass. And dispersion using an ultrasonic homogenizer. After the ethyl acetate was removed from the solution under reduced pressure, the solid content concentration was adjusted to 20% by mass. Thus, an amorphous resin fine particle dispersion (AA-1) in which fine particles of the amorphous resin (A1) were dispersed in an aqueous medium was prepared. The volume-based median diameter of the fine particles of the amorphous resin (A1) in the dispersion was 200 nm.

<Preparation of Colorant Fine Particle Dispersion (Cyan)>
After adding 50 parts by mass of copper phthalocyanine (CI Pigment Blue 15: 3) to a surfactant aqueous solution dissolved in 200 parts by mass of ion-exchanged water so as to have a concentration of 1% by mass of sodium alkyldiphenyl ether disulfonate, Dispersion treatment was performed using a sonic homogenizer. The solid content concentration was adjusted to 20% by mass. As a result, a colorant fine particle dispersion (1) in which colorant fine particles are dispersed in an aqueous medium was prepared. The volume-based median diameter of the colorant fine particles in the colorant fine particle dispersion (1) was measured using a Microtrac particle size distribution measuring apparatus “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).

<Preparation of release agent fine particle dispersion>
As a release agent, 200 parts by mass of behenyl behenate (melting point: 72 ° C.) was heated to 95 ° C. and dissolved. This was further added to a surfactant aqueous solution dissolved in 800 parts by mass of ion-exchanged water so that the sodium alkyldiphenyl ether disulfonate had a concentration of 3% by mass, followed by dispersion treatment using an ultrasonic homogenizer. The solid content concentration was adjusted to 20% by mass. Thus, a release agent fine particle dispersion liquid (1) in which release agent fine particles are dispersed in an aqueous medium was prepared.
The volume-based median diameter of the release agent fine particles in the release agent fine particle dispersion (1) was measured using a Microtrac particle size distribution measuring device “Microtrack UPA-150” (manufactured by Nikkiso Co., Ltd.), and was 150 nm. .

[Production of Toner 1]
Crystalline resin fine particle dispersion (CA-1) 5 parts by mass (solid content conversion)
Release agent fine particle dispersion (1) 5 parts by mass (solid content conversion)
295 parts by mass of ion-exchanged water 4.5 parts by mass of an anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical Company)

The above components were put into a 3 liter reaction vessel equipped with a stirrer, a thermometer and a pH meter, and at a temperature of 25 ° C., 0.3 M nitric acid was added to adjust the pH to 2.5.
Next, while dispersing at 5000 rpm with a homogenizer (IKA Japan, Inc .: Ultra Tarax T50), as an aggregating agent, an aqueous aluminum sulfate solution (aggregating agent F1, 0.2975 mass%: solid content 0.18 g) 12.4 mass Part was added over 2 minutes. In addition, aluminum sulfate aqueous solution throws 35 mass parts of aluminum sulfate powders (Asada Chemical Industry Co., Ltd .: 17% aluminum sulfate) and 1965 mass parts of ion-exchanged water into a 2 liter container, and precipitates at 30 ° C. It was prepared by stirring and mixing until the product disappeared.
After that, a stirrer and a mantle heater are installed in the reaction vessel, and the temperature is raised at a rate of 0.2 ° C./min up to a temperature of 40 ° C. while adjusting the rotation speed of the stirrer so that the slurry is sufficiently stirred. did. At this time, the particle size was not yet measurable with Multisizer 3 (aperture diameter: 50 μm, manufactured by Beckman Coulter, Inc.). The process so far is referred to as “first process”.

Crystalline resin fine particle dispersion (CA-1) 5 parts by mass (solid content conversion)
Amorphous resin fine particle dispersion (AA-1) 81 parts by mass (solid content conversion)
Release agent fine particle dispersion (1) 5 parts by mass (solid content conversion)
Colorant fine particle dispersion (1) 8 parts by mass (solid content conversion)

After reaching 40 ° C., the mixture was sufficiently stirred in a separate container, and the above components adjusted to pH 2.5 were charged into the reaction container at 100 mL / min in the same manner as in the first step. Furthermore, 49.6 parts by mass of an aluminum sulfate aqueous solution (flocculating agent F1) produced in the same manner as in the first step was added over 5 minutes. Thereafter, the temperature was raised at a rate of temperature increase of 0.05 ° C./min, and the volume average particle size was measured with Multisizer 3 (aperture diameter: 50 μm, manufactured by Beckman Coulter, Inc.) every 10 minutes. The process so far is referred to as “second process”, and the component added after reaching 40 ° C. is referred to as “component added in“ second process ”.
When the volume average particle diameter reached 5.0 μm, the temperature rise was stopped, and 9 parts by mass (in terms of solid content) of amorphous resin fine particle dispersion (AA-1) was taken as a resin fine particle dispersion for shell over 1 hour. And dripped. Thereafter, the pH was adjusted to 8.5 using a 0.5N aqueous sodium hydroxide solution. Thereafter, the temperature is raised to 85 ° C. at a rate of temperature rise of 1 ° C./min while maintaining the pH to 8.5 every 5 ° C. in the same manner, and kept at 85 ° C., and FPIA-2000 (manufactured by Sysmex) ) Was used to cool to 60 ° C. at 10 ° C./min, and then to room temperature (25 ° C.) at 0.1 ° C./min. The slurry after cooling is passed through a nylon mesh with an opening of 20 μm to remove coarse powder, and the toner slurry that has passed through the mesh is adjusted to pH 6.0 by adding nitric acid at room temperature (25 ° C.), and then reduced in pressure with an aspirator. Filtered. The toner remaining on the filter paper is crushed as finely as possible by hand, poured into ion-exchanged water 10 times the amount of toner at a temperature of 30 ° C., stirred and mixed for 30 minutes, filtered again with an aspirator, and the electrical conductivity of the filtrate. Was measured. This operation was repeatedly washed until the electric conductivity of the filtrate was 10 μS / cm or less, whereby a base toner was obtained.

  The base toner was finely crushed with a wet dry granulator (Comil) and then vacuum dried in an oven at 35 ° C. for 36 hours to obtain toner particles. With respect to 100 parts by mass of the obtained toner particles, as external additives, 1.5 parts of hydrophobic large-diameter silica fine particles having an average particle diameter of 100 nm, 0.6 parts of hydrophobic silica fine particles having an average particle diameter of 20 nm, and an average particle diameter 0.3 parts of 20 nm titanium oxide fine particles and 0.1 parts of strontium titanate fine particles having an average particle diameter of 500 nm were mixed using a Henschel mixer. Thereafter, toner 1 was obtained by sieving with a vibrating sieve having an opening of 45 μm. The obtained cyan toner had a volume average particle diameter D50v of 5.8 μm and an average circularity of 0.960. When the SEM image of the toner was observed, it had a smooth surface, and no problems such as protrusion of the release agent and peeling of the surface layer were observed.

[Production of Toner 2, 3, 6 to 11]
Table 3 shows the types and amounts of the crystalline resin fine particle dispersion used in the first step and the second step, the amount of the release agent fine particle dispersion, and the amount of the aqueous aluminum sulfate solution (flocculating agent F1) to be added. A toner was prepared in the same manner as toner 1 except that the change was made.

[Production of Toners 4 and 5]
The crystalline resin fine particle dispersion used in the first step and the second step was prepared in the same manner as the toner 1 except that the type of the crystalline resin fine particle dispersion was changed to that shown in Table 3 and the crystal growth step was increased. Specifically, the crystal growth step refers to cooling to room temperature, raising the temperature to 40 ° C. at 1 ° C./min, holding for 40 minutes when reaching 40 ° C., and then to room temperature (25 ° C.) This is a step of cooling at 0.1 ° C / min.

[Preparation of Toner 12]
Except for changing the aggregating agent from an aluminum sulfate aqueous solution (aggregating agent F1) to a magnesium chloride aqueous solution (aggregating agent F2, a 29.8% by mass solution of magnesium chloride hexahydrate), the same as the toner 3 A toner was prepared by this method.

[Preparation of Toner 13]
Except that the flocculant was changed from an aluminum sulfate aqueous solution (flocculating agent F1) to an iron (III) chloride aqueous solution (flocculating agent F3, 0.298% by mass solution of iron (III) chloride hexahydrate). A toner was prepared in the same manner as in Toner 3.

[Preparation of Toner 14]
Crystalline resin fine particle dispersion (CA-3) 5 parts by mass (solid content conversion)
Release agent fine particle dispersion (1) 5 parts by mass (solid content conversion)
295 parts by mass of ion-exchanged water 4.5 parts by mass of an anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical Company)

The above components were put into a 3 liter reaction vessel equipped with a stirrer, a thermometer and a pH meter, and at a temperature of 25 ° C., 0.3 M nitric acid was added to adjust the pH to 2.5.
Next, while dispersing at 5000 rpm with a homogenizer (IKA Japan, Inc .: Ultra Tarax T50), as an aggregating agent, an aqueous aluminum sulfate solution (aggregating agent F1, 0.2975 mass%: solid content 0.18 g) 12.4 mass Part was added over 2 minutes. The aqueous aluminum sulfate solution was charged with 35 parts by mass of aluminum sulfate powder (17% aluminum sulfate manufactured by Asada Chemical Industry Co., Ltd.) and 1965 parts by mass of ion-exchanged water in a 2 liter container at 30 ° C. It was prepared by stirring and mixing until the precipitate disappeared.
After that, a stirrer and a mantle heater are installed in the reaction vessel, and the temperature is raised at a rate of 0.2 ° C./min up to a temperature of 40 ° C. while adjusting the rotation speed of the stirrer so that the slurry is sufficiently stirred. did. At this time, the particle size was not yet measurable with Multisizer 3 (aperture diameter: 50 μm, manufactured by Beckman Coulter, Inc.).

Crystalline resin fine particle dispersion (CA-3) 5 parts by mass (solid content conversion)
Amorphous resin fine particle dispersion (AA-1) 90 parts by mass (solid content conversion)
Release agent fine particle dispersion (1) 5 parts by mass (solid content conversion)
Colorant fine particle dispersion (1) 8 parts by mass (solid content conversion)

After reaching 40 ° C., the mixture was sufficiently stirred in a separate container, and the above components adjusted to pH 2.5 were charged into the reaction container at 100 mL / min in the same manner as in the first step. Furthermore, 49.6 parts by mass of an aluminum sulfate aqueous solution (flocculating agent F1) produced in the same manner as in the first step was added over 5 minutes. Thereafter, the temperature was raised at a rate of temperature increase of 0.05 ° C./min, and the volume average particle size was measured with Multisizer 3 (aperture diameter: 50 μm, manufactured by Beckman Coulter, Inc.) every 10 minutes.
When the volume average particle diameter reached 5.8 μm, the temperature increase was stopped, and then the pH was adjusted to 8.5 using a 0.5N aqueous sodium hydroxide solution. Thereafter, the temperature is raised to 85 ° C. at a rate of temperature rise of 1 ° C./min while maintaining the pH to 8.5 every 5 ° C. in the same manner, and kept at 85 ° C., and FPIA-2000 (manufactured by Sysmex) ) Was used to cool to 60 ° C. at 10 ° C./min, and then to room temperature (25 ° C.) at 0.1 ° C./min. The cooled slurry was passed through a nylon mesh having a mesh size of 20 μm to remove coarse powder, and the toner slurry passed through the mesh was adjusted to pH 6.0 by adding nitric acid, and then filtered under reduced pressure with an aspirator. The toner remaining on the filter paper is crushed as finely as possible by hand, poured into ion-exchanged water 10 times the amount of toner at a temperature of 30 ° C., stirred and mixed for 30 minutes, filtered again with an aspirator, and the electrical conductivity of the filtrate. Was measured. This operation was repeatedly washed until the electric conductivity of the filtrate was 10 μS / cm or less, whereby a base toner was obtained.

  The base toner was finely crushed with a wet dry granulator (Comil) and then vacuum dried in an oven at 35 ° C. for 36 hours to obtain toner particles. With respect to 100 parts by mass of the obtained toner particles, as external additives, 1.5 parts of hydrophobic large-diameter silica fine particles having an average particle diameter of 100 nm, 0.6 parts of hydrophobic silica fine particles having an average particle diameter of 20 nm, and an average particle diameter 0.3 parts of 20 nm titanium oxide fine particles and 0.1 parts of strontium titanate fine particles having an average particle diameter of 500 nm were mixed using a Henschel mixer. Thereafter, the toner 14 was obtained by sieving with a vibrating sieve having an opening of 45 μm. The obtained cyan toner had a volume average particle diameter D50v of 5.8 μm and an average circularity of 0.960. In addition, when an SEM image of the toner was observed, a minute substance that seems to be a crystalline resin was slightly exposed.

[Preparation of Toner 15]
A toner 15 was produced in the same manner as in the toner 3 except that the hydrophobic large-diameter silica fine particles having an average particle diameter of 100 nm were not added in the toner 3.

[Production of Toner 16]
Toner 16 was prepared in the same manner as toner 3 except that the strontium titanate fine particles having an average particle diameter of 500 nm were not added to toner 3.

[Preparation of Toner 17]
A toner 17 was produced in the same manner as in the toner 3 except that the hydrophobic large-diameter silica fine particles having an average particle diameter of 100 nm and the strontium titanate fine particles having an average particle diameter of 500 nm were not added.

[Preparation of Toner 18]
<Preparation of aqueous dispersion of crystalline resin fine particles and amorphous resin fine particles>
After dissolving 81 parts by mass of the amorphous resin (A1) and 5 parts by mass of the crystalline resin (C1) in 200 parts by mass of ethyl acetate, the concentration of sodium polyoxyethylene lauryl ether sulfate in 800 parts by mass of ion-exchanged water is 1. It mixed with the aqueous solution dissolved so that it might become 3 mass%, and it disperse | distributed using the ultrasonic homogenizer. After the ethyl acetate was removed from the solution under reduced pressure, the solid content concentration was adjusted to 20% by mass. Thereby, a resin fine particle dispersion (BA-1) in which fine particles of an amorphous resin (A1) and a crystalline resin (C1) were dispersed in an aqueous medium was prepared. The volume-based median diameter of the fine particles was 165 nm.

Crystalline resin fine particle dispersion (CA-1) 5 parts by mass (solid content conversion)
Release agent fine particle dispersion (1) 5 parts by mass (solid content conversion)
295 parts by mass of ion-exchanged water Anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical Company): 4.5 parts by mass

The above components were put into a 3 liter reaction vessel equipped with a stirrer, a thermometer and a pH meter, and at a temperature of 25 ° C., 0.3 M nitric acid was added to adjust the pH to 2.5.
Next, while dispersing at 5000 rpm with a homogenizer (IKA Japan, Inc .: Ultra Tarax T50), as an aggregating agent, an aqueous aluminum sulfate solution (aggregating agent F1, 0.2975 mass%: solid content 0.18 g) 12.4 mass Part was added over 2 minutes. The aluminum sulfate aqueous solution (flocculating agent F1) was charged into a 2 liter container with 35 parts by weight of aluminum sulfate powder (Asada Chemical Industries, Ltd .: 17% aluminum sulfate) and 1965 parts by weight of ion-exchanged water. It was prepared by stirring and mixing at 30 ° C. until the precipitate disappeared.
After that, a stirrer and a mantle heater are installed in the reaction vessel, and the temperature is raised at a rate of 0.2 ° C./min up to a temperature of 40 ° C. while adjusting the rotation speed of the stirrer so that the slurry is sufficiently stirred. did. At this time, the particle size was not yet measurable with Multisizer 3 (aperture diameter: 50 μm, manufactured by Beckman Coulter, Inc.).

Resin fine particle dispersion (BA-1) 86 parts by mass (solid content conversion)
Release agent fine particle dispersion (1) 5 parts by mass (solid content conversion)
Colorant fine particle dispersion (1) 8 parts by mass (solid content conversion)

After reaching 40 ° C., the mixture was sufficiently stirred in a separate container, and the above components adjusted to pH 2.5 were charged into the reaction container at 100 mL / min in the same manner as in the first step. Furthermore, 49.6 parts by mass of an aluminum sulfate aqueous solution (flocculating agent F1) produced in the same manner as in the first step was added over 5 minutes. Thereafter, the temperature was raised at a rate of temperature increase of 0.05 ° C./min, and the volume average particle size was measured with Multisizer 3 (aperture diameter: 50 μm, manufactured by Beckman Coulter, Inc.) every 10 minutes.
When the volume average particle diameter reached 5.0 μm, the temperature rise was stopped, and 9 parts by mass (in terms of solid content) of amorphous resin fine particle dispersion (AA-1) was taken as a resin fine particle dispersion for shell over 1 hour. And dripped. Thereafter, the pH was adjusted to 8.5 using a 0.5N aqueous sodium hydroxide solution. Thereafter, the temperature is raised to 85 ° C. at a rate of temperature rise of 1 ° C./min while maintaining the pH to 8.5 every 5 ° C. in the same manner, and kept at 85 ° C., and FPIA-2000 (manufactured by Sysmex) ) Was used to cool to 60 ° C. at 10 ° C./min, and then to room temperature (25 ° C.) at 0.1 ° C./min. The cooled slurry was passed through a nylon mesh having a mesh size of 20 μm to remove coarse powder, and the toner slurry passed through the mesh was adjusted to pH 6.0 by adding nitric acid, and then filtered under reduced pressure with an aspirator. The toner remaining on the filter paper is crushed as finely as possible by hand, poured into ion-exchanged water 10 times the amount of toner at a temperature of 30 ° C., stirred and mixed for 30 minutes, filtered again with an aspirator, and the electrical conductivity of the filtrate. Was measured. This operation was repeatedly washed until the electric conductivity of the filtrate was 10 μS / cm or less, whereby a base toner was obtained.
The base toner was finely crushed with a wet dry granulator (Comil) and then vacuum dried in an oven at 35 ° C. for 36 hours to obtain toner particles. With respect to 100 parts by mass of the obtained toner particles, as external additives, 1.5 parts of hydrophobic large-diameter silica fine particles having an average particle diameter of 100 nm, 0.6 parts of hydrophobic silica fine particles having an average particle diameter of 20 nm, and an average particle diameter 0.3 parts of 20 nm titanium oxide fine particles and 0.1 parts of strontium titanate fine particles having an average particle diameter of 500 nm were mixed using a Henschel mixer. Thereafter, the toner 18 was obtained by sieving with a vibrating sieve having an opening of 45 μm. The obtained cyan toner had a volume average particle diameter D50v of 5.8 μm and an average circularity of 0.960. Note that when an SEM image of the toner was observed, a small amount of a fine substance that seemed to be a crystalline resin was slightly exposed.

[Preparation of Toner 19]
In the crystal growth step, after cooling to room temperature, the temperature is raised to 40 ° C. at 1 ° C./min. When reaching 40 ° C., the temperature is maintained for 120 minutes, and then 0.1 ° C./min to room temperature (25 ° C.). A toner 19 was produced in the same manner as the toner 5 except that the toner 19 was cooled.

[Preparation of Toner 20]
Crystalline resin fine particle dispersion CA-3 10 parts by mass (solid content conversion)
Amorphous resin fine particle dispersion AA-1 81 parts by mass (solid content conversion)
Release agent fine particle dispersion (1) 10 parts by mass (solid content conversion)
Colorant fine particle dispersion (1) 8 parts by mass (solid content conversion)
295 parts by mass of ion-exchanged water 4.5 parts by mass of an anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical Company)

The above components were put into a 3 liter reaction vessel equipped with a stirrer, a thermometer and a pH meter, and at a temperature of 25 ° C., 0.3 M nitric acid was added to adjust the pH to 2.5.
Subsequently, 62 parts by mass of an aqueous aluminum sulfate solution (flocculating agent F1) was added over 7 minutes while dispersing at 5000 rpm with a homogenizer (manufactured by IKA Japan: Ultra Tarax T50) (0.2975% by mass: solid content 0). .18 g). The aqueous aluminum sulfate solution was charged with 35 parts by mass of aluminum sulfate powder (17% aluminum sulfate manufactured by Asada Chemical Industry Co., Ltd.) and 1965 parts by mass of ion-exchanged water in a 2 liter container at 30 ° C. It was prepared by stirring and mixing until the precipitate disappeared.
Thereafter, a stirrer and a mantle heater are installed in the reaction vessel, and the temperature rise rate is 0.2 ° C./min up to a temperature of 40 ° C. while adjusting the rotation speed of the stirrer so that the slurry is sufficiently stirred. After exceeding the temperature, the temperature was increased at a rate of temperature increase of 0.05 ° C./min, and the volume average particle size was measured with a multisizer 3 (aperture diameter: 50 μm, manufactured by Beckman Coulter, Inc.) every 10 minutes.
When the volume average particle diameter reached 5.0 μm, the temperature rise was stopped, and 9 parts by mass (in terms of solid content) of amorphous resin fine particle dispersion (AA-1) was taken as a resin fine particle dispersion for shell over 1 hour. And dripped. Thereafter, the pH was adjusted to 8.5 using a 0.5N aqueous sodium hydroxide solution. Thereafter, the temperature is raised to 85 ° C. at a rate of temperature rise of 1 ° C./min while maintaining the pH to 8.5 every 5 ° C. in the same manner, and kept at 85 ° C., and FPIA-2000 (manufactured by Sysmex) ) Was used to cool to 60 ° C. at 10 ° C./min, and then to room temperature (25 ° C.) at 0.1 ° C./min. The cooled slurry was passed through a nylon mesh having a mesh size of 20 μm to remove coarse powder, and the toner slurry passed through the mesh was adjusted to pH 6.0 by adding nitric acid, and then filtered under reduced pressure with an aspirator. The toner remaining on the filter paper is crushed as finely as possible by hand, poured into ion-exchanged water 10 times the amount of toner at a temperature of 30 ° C., stirred and mixed for 30 minutes, filtered again with an aspirator, and the electrical conductivity of the filtrate. Was measured. This operation was repeatedly washed until the electric conductivity of the filtrate was 10 μS / cm or less, whereby a base toner was obtained.
The base toner was finely crushed with a wet dry granulator (Comil) and then vacuum dried in an oven at 35 ° C. for 36 hours to obtain toner particles. With respect to 100 parts by mass of the obtained toner particles, as external additives, 1.5 parts of hydrophobic large-diameter silica fine particles having an average particle diameter of 100 nm, 0.6 parts of hydrophobic silica fine particles having an average particle diameter of 20 nm, and an average particle diameter 0.3 parts of 20 nm titanium oxide fine particles and 0.1 parts of strontium titanate fine particles having an average particle diameter of 500 nm were mixed using a Henschel mixer. Thereafter, toner 20 was obtained by sieving with a vibrating sieve having an opening of 45 μm. The obtained cyan toner had a volume average particle diameter D50v of 5.8 μm and an average circularity of 0.960. When the SEM image of the toner was observed, it had a smooth surface, and no problems such as protrusion of the release agent and peeling of the surface layer were observed.
As described above, since the toner 20 is manufactured by the method that does not include the first step and the second step, the addition amount in the first step and the addition amount in the second step are shown in Table 3. Is shown as “−”.

[Preparation of Toner 21]
Table 3 shows the types and amounts of the crystalline resin fine particle dispersion used in the first step and the second step, the types and amounts of the release agent dispersion, and the amount of the aqueous aluminum sulfate solution (flocculating agent F1) to be added. A toner 21 was produced in the same manner as the toner 3 except that the toner 21 was changed.

<Cross-section observation of toner particles>
According to the observation method described below, the cross sections of the toner particles of the produced toner 1 to toner 21 were observed. In the toners of toners 1 to 19, both the connected crystal structure and the thread crystal structure were confirmed on the cross section of 60% (60) or more of the 100 toner particles. With respect to the toner 20, a connected crystal structure could not be observed in all cross sections of 100 toner particles. I was able to observe. In addition, with regard to the toner 21, the connected crystal structure can be observed in the cross section of 60% (60) or more of the 100 toner particles. Could not be observed.

(Observation conditions)
Apparatus: Electron microscope “JSM-7401F” (manufactured by JEOL Ltd.)
Sample: A section of toner base particles stained with ruthenium tetroxide (RuO ₄ ) (section thickness: 60 to 100 nm)
Acceleration voltage: 30 kV
Magnification: 50000 times, bright field image

(Method for preparing a section of toner base particles)
After 3 parts by weight of the prepared toner was added and dispersed in 35 parts by weight of a 0.2% aqueous solution of polyoxyethyl phenyl ether, ultrasonic waves (Nippon Seiki Co., Ltd., US-1200T) were used at 25 ° C. for 5 minutes. The external additive was removed from the toner surface to obtain toner base particles for observation.
1 to 2 mg of the toner base particles obtained above is put in a 10 mL sample bottle, dyed under the ruthenium tetroxide (RuO ₄ ) vapor dyeing conditions shown below, and then photocurable resin “D-800” (Japan) The block was formed by dispersing and photocuring. Next, an ultrathin sample having a thickness of 60 to 100 nm was cut out from the above block using a microtome equipped with diamond teeth.

(Ruthenium tetroxide staining conditions)
Ruthenium tetroxide staining was performed using a vacuum electron staining apparatus VSC1R1 (manufactured by Philgen). In accordance with the apparatus procedure, a sublimation chamber containing ruthenium tetroxide was installed in the staining apparatus body, and after the prepared ultrathin section was introduced into the staining chamber, the staining conditions with ruthenium tetroxide were room temperature (24-25 ° C.), It dye | stained on the conditions of density | concentration 3 (300 Pa) and time 10 minutes.

(Observation of crystal structure)
Within 24 hours after dyeing, an electron microscope “JSM-7401F” (manufactured by JEOL Ltd.) was used to observe with a transmission electron detector. Among the observed domains, the domain portion that was stained lighter was observed as the release agent domain, and the domain portion that was stained more intensely was observed as the crystalline resin domain (filamentous crystal structure). When it was difficult to distinguish the degree of staining, a domain in which the average major axis of the crystal structure was at least 10 times the average minor axis was measured as a domain of the crystalline resin.

(Measuring method of average domain diameter of linked crystal structure and average major axis and average minor axis of filamentous crystal structure)
The domain diameter of the connected crystal structure in the cross section of the toner particle was calculated by the horizontal maximum chord length (CORD H). Specifically, a photographic image obtained by photographing a cross section of toner base particles produced in the same manner as described above is taken in by a scanner, and the horizontal direction of the connected crystal structure is measured using an image processing analysis device LUZEX AP (manufactured by Nireco Corporation). The maximum chord length (CORD H) was measured and obtained.
In addition, the major axis and minor axis of the filamentous crystal structure are obtained by observing a photographic image observed in the same manner as described above by using an image processing analysis apparatus LUZEX AP (manufactured by Nireco Corporation). LNG), the minor axis (minor axis) was calculated using the width (BR'DTH).
The average domain diameter of the linked crystal structure, and the average major axis and the average minor axis of the thread crystal structure were measured for both the coupled crystal structure and the thread crystal structure out of 100 toner particles. It was calculated as an arithmetic average value for the thing.
The cross section of the toner particles used in these measurements is ± 10% of the volume average particle diameter of the toner particles, that is, in this embodiment, the cross section of the toner particles that is 5.8 μm ± 0.58 μm is selected and observed. did.
Table 4 shows the average domain diameter of the linked crystal structure measured in this way, and the average major axis and average minor axis of the filamentous crystal structure.

(Method for calculating the cross-sectional area ratio of the cross-section of the toner particles)
As for the cross-sectional areas of the connected crystal structure, the thread-like crystal structure, and the domain part of the release agent in the cross-section of the toner particles, a photographic image obtained by observing the cross-section of the toner particles described above is used as an image processing analyzer LUZEX AP (manufactured by Nireco Corporation). ) “Area AREA”.
Here, by observing 100 toner particles and calculating the arithmetic average value, the average ratio A of the cross-sectional area of the connected crystal structure to the cross-sectional area of the toner particle, the average ratio B of the cross-sectional area of the thread crystal structure, The average ratio C of the cross-sectional area of the domain part of the release agent existing independently of the crystalline resin was calculated.
Table 4 shows values obtained by calculating “A / (A + B + C)” from the calculated average ratio A, average ratio B, and average ratio C.

<Measurement of metal concentration>
The metal concentration in the toner particles was measured by acid decomposition / inductively coupled plasma emission spectrometry by the following method. The measurement results are shown in Table 4 below.

(Preprocessing)
100 mg of toner particles were decomposed with sulfuric acid and nitric acid in a sealed microwave decomposition apparatus “Milestone General Co., Ltd., ETHOS1”. Further, the target component was eluted from the undecomposed product using hydrochloric acid, hydrofluoric acid, and hydrogen peroxide. The decomposition solution was appropriately diluted with ultrapure water. As these reagents, ultra-high purity reagents manufactured by Kanto Chemical Co., Inc. were used.

(Measurement)
Using a high frequency inductively coupled plasma optical emission spectrometer (ICP-OES, manufactured by Hitachi High-Tech Science Co., Ltd., SPS3520UV), the concentration was measured at 167.079 nm for Al, 279.553 nm for Mg, and 259.940 nm for Fe. A calibration curve was prepared by adding a standard solution for atomic absorption of each element manufactured by Kanto Chemical Co. to a decomposition solution containing no sample, and adjusting the acid concentration to be the same as the sample solution.

<Production of developer>
100 parts by mass of ferrite core and 5 parts by mass of copolymer resin particles of cyclohexyl methacrylate / methyl methacrylate (copolymerization ratio 5/5) are put into a high-speed mixer equipped with stirring blades and stirred and mixed at 120 ° C. for 30 minutes. Thus, a resin coat layer was formed on the surface of the ferrite core by the action of mechanical impact force to obtain a carrier having a volume-based median diameter of 40 μm.
The volume-based median diameter of the carrier was measured with a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympathic) equipped with a wet disperser. Toners 1 to 21 are added to the carrier so that the toner concentration is 7% by mass, and the mixture is put into a micro-type V-type mixer (Tsutsui Riken Kikai Co., Ltd.), mixed at a rotational speed of 45 rpm for 30 minutes, and developed. 1-21 were produced.

<Evaluation>
Evaluation was performed as follows, and the low-temperature fixability, fixing separation property, toner scattering, and laminate adhesion of each toner were evaluated. The evaluation results are shown in Table 4 below.

<Image forming method>
In the following evaluation, the image evaluation was performed on a commercially available color multifunction peripheral “bizhub PRO C6500 (manufactured by Konica Minolta)” with a modified machine modified so that the fixing temperature, the toner adhesion amount, and the system speed can be freely set. The apparatus was evaluated by sequentially loading the toner prepared above and a developer.

<Evaluation of low-temperature fixability (under offset)>
In a fixing experiment in which a solid image with a toner adhesion amount of 8 g / m ² is fixed in an environment of normal temperature and humidity (temperature 20 ° C., humidity 50% RH), the temperature of the lower fixing roller is set 20 ° C. lower than the upper fixing belt. Then, the temperature of the fixing upper belt was repeatedly increased from 110 ° C. to 200 ° C. while being changed in steps of 5 ° C. This experiment was performed at a fixing speed of 300 mm / sec. Evaluation was performed using API-sized NPI 64.0 g / m ² (manufactured by Nippon Paper Industries Co., Ltd.).
Here, under offset refers to an image defect that peels off from a transfer material such as recording paper because the toner layer is not sufficiently melted by the heat applied when passing through the fixing machine. Among the fixing experiments in which image staining due to under-offset is not visually observed, the fixing temperature of the fixing experiment relating to the lowest fixing temperature was evaluated as the minimum fixing temperature. In the present invention, the lower the minimum fixing temperature, the better the fixability. According to the following criteria, “◯” or “Δ” (minimum fixing temperature of less than 160 ° C.) was determined to be acceptable.

(Criteria)
○: Minimum fixing temperature (° C.) is less than 150 ° C. Δ: Minimum fixing temperature (° C.) is 150 ° C. or higher and lower than 160 ° C. ×: Minimum fixing temperature (° C.) is 160 ° C. or higher.

<Evaluation of fixing separation>
The tip of the paper “Kanafuji 85g / m ² T eyes” (manufactured by Oji Paper Co., Ltd.), which was conditioned overnight in a room temperature and humidity environment (temperature 20 ° C., humidity 50% RH) using the above-described color multifunction device. Set the temperature of the upper heating and pressing member as the minimum fixing temperature + 20 ° C. previously determined as the margin 5 mm and the fixing temperature, set the temperature of the lower heating and pressing member to −60 ° C. of the upper heating and pressing member, All solid images are printed with varying amounts of adhesion, and the amount of adhesion (g / m ² ) of the solid image immediately before the occurrence of a paper jam (jam) is measured. The scale of Write this value is large, the fixing separation performance is good, ○ or △ by the following criteria (adhesion amount 2.0 g / m ² or higher) were evaluated as acceptable.

(Criteria)
○: Separation limit adhesion amount (g / m ² ) is 3.0 g / m ² or more Δ: Separation limit adhesion amount (g / m ² ) is 2.0 g / m ² or more and less than 3.0 g / m ² ×: Separation The limit adhesion amount (g / m ² ) is less than 2.0 g / m ²

<Evaluation of toner scattering>
Toner scattering in the machine was evaluated by a commercially available color multifunction machine “bizhub PRESS C6500 (manufactured by Konica Minolta)”. In a high-temperature and high-humidity (30 ° C./80% RH) environment, after 100,000 sheets of white paper were printed, the state of toner scattering in the machine was visually observed and evaluated according to the following evaluation criteria. According to the following criteria, if it was (circle) or (triangle | delta), it was set as the pass.

(Criteria)
○: The inside of the machine is not contaminated with toner. Δ: Slight toner scattering to the inside of the machine is observed, but there is no problem in the output image. State

<Evaluation of adhesion of laminate>
Images were created under the following conditions under ambient conditions of normal temperature and humidity (20 ° C., 55% RH).
(Image creation conditions)
・ Condition 1
Paper type: A4 size NPI 64.0 g / m ² (Nippon Paper Industries)
Adhering amount: 8 g / m ²
Fixing temperature:
Upper heating pressure member temperature: minimum fixing temperature + 20 ° C
Temperature of lower heating and pressing member: Temperature of upper heating and pressing member −20 ° C.
Line speed: 300mm / s
・ Condition 2
Paper type: A4 size mirror coated platinum paper 256g / m ² (Oji Paper)
Adhering amount: 8 g / m ²
Fixing temperature:
Upper heating pressure member temperature: minimum fixing temperature + 50 ° C
Temperature of lower heating and pressing member: Temperature of upper heating and pressing member −20 ° C.
Line speed: 200mm / s

Subsequently, the paper on which an image was created under the above conditions 1 and 2 was laminated under the following conditions, and left for 7 days in an environment of normal temperature and humidity (20 ° C., 55% RH).
(Lamination condition)
Apparatus: 4-roller laminator (L3250, manufactured by Asuka)
Speed: Speed “3”
Laminator exclusive film: Asmix Laminator exclusive film (thickness 100μm, A4 size)

  Thereafter, the side of the laminate image was dropped 6 times from a height of 20 cm, and the presence or absence of a part where the laminate material and the image were peeled was visually evaluated. According to the following judgment criteria, it was determined to be acceptable if it was ○ or Δ.

(Criteria)
○: There is no portion where the toner and the laminate material are peeled off from the transfer paper.
Δ: There is a portion where the toner and the laminate material are peeled off from the transfer paper at only one place.
X: There are a plurality of portions where the toner and the laminate material are peeled off from the transfer paper.

  As is apparent from the results shown in Table 4, the toners 1 to 17 of the present invention all exhibited excellent performance from the viewpoints of low-temperature fixability, fixing separation property and toner scattering. On the other hand, the toners 18 to 21 of the comparative examples were inferior in any item.

1 Matrix 2 Domain of linked crystal structure 3 Domain of filamentous crystal structure 4 Domain of release agent 5 Domain of lamellar crystal structure

Claims (10)

An electrostatic latent image developing toner comprising at least toner particles containing a binder resin and a release agent,
As the binder resin, containing an amorphous polyester resin and a crystalline resin,
Containing the amorphous polyester resin as a main component of the resin contained in the toner particles;
In the toner particles, there are a domain of a linked crystal structure in which the crystalline resin is in contact with the release agent, and a domain of a filamentous crystal structure of the crystalline resin that exists independently of the release agent. Exists and
An electrostatic latent image developing toner, wherein an average major axis of the thread crystal structure is in a range of 200 to 2000 nm in a cross section of the toner particles.   2. The electrostatic latent image developing toner according to claim 1, wherein an average major axis of the thread crystal structure is in a range of 400 to 2000 nm in a cross section of the toner particles.   The electrostatic latent image developing toner according to claim 1, wherein the crystalline resin contains a crystalline polyester resin.   4. The electrostatic latent image according to claim 1, wherein an average domain diameter of the connected crystal structure is in a range of 300 to 2500 nm in a cross section of the toner particle. 5. Toner for image development. In the cross section of the toner particle, the average ratio of the cross-sectional area of the connected crystal structure to the cross-sectional area of the toner particle is A, the average ratio of the cross-sectional area of the thread crystal structure is B, and independent of the crystalline resin. The following formula (1) is satisfied, where C is the average ratio of the cross-sectional areas of the domain parts of the release agent that exists in the release agent, according to any one of claims 1 to 4. Toner for electrostatic latent image development.
Formula (1): 0.35 ≦ A / (A + B + C) ≦ 0.65 The metal concentration in the toner particles is in the range of 20 to 2000 ppm by mass;
The metal concentration is a concentration of a metal derived from at least one metal element selected from aluminum (Al), magnesium (Mg), and iron (Fe). The electrostatic latent image developing toner according to any one of the above.   The toner for electrostatic latent image development according to any one of claims 1 to 6, wherein the toner particles have a core-shell structure in which a shell layer is coated on the surface of the core particles. .   8. The toner particles according to claim 1, wherein the toner particles contain inorganic titanic acid compound fine particles having an average particle diameter in the range of 0.5 to 3.0 [mu] m as an external additive. The toner for developing an electrostatic latent image according to the item.   9. The toner particles according to claim 1, wherein the toner particles contain large-sized silica fine particles having an average particle diameter in the range of 0.1 to 1.0 [mu] m as an external additive. The electrostatic latent image developing toner according to 1. A method for producing a toner for developing an electrostatic latent image according to any one of claims 1 to 9,
By adding an aggregating agent to a dispersion liquid in which at least crystalline resin fine particles, amorphous resin fine particles and release agent fine particles are dispersed in an aqueous medium, these fine particles are aggregated to form aggregated particles. A process for producing a toner for developing an electrostatic latent image, comprising the step of:

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