JP6056704B2 - Electrostatic image developing toner, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Description

  The present invention relates to an electrostatic charge image developing toner, an electrostatic charge image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method.

  In recent years, toner containing particles having a core / shell structure has been used for various purposes in electrophotographic image forming apparatuses.

  For example, Patent Document 1 discloses an electrophotographic toner containing a binder resin and a colorant and having a core-shell structure, in which the core mainly includes a crystalline resin, and the shell is 15% by mass or more and 120% by mass or more with respect to the core. An electrophotographic toner is disclosed wherein the toner has a mass% or less, the shell has hemispherical protrusions having a step of 0.3 μm or more, and the shell is produced by an emulsion aggregation method.

  For example, Patent Document 2 discloses a toner for electrostatic charge development having a core-shell structure having a core layer composed of toner base particles containing a binder resin and a colorant, and a shell layer covering the core layer. Further, an electrostatic charge image developing toner is disclosed, wherein the shell layer contains an amorphous polymer obtained by polymerizing an alicyclic monomer having 11 to 14 carbon atoms.

  Further, for example, in Patent Document 3, a latent image forming step for forming an electrostatic latent image on the surface of the latent image holding member, development for developing the electrostatic latent image with a developer containing toner, and forming a toner image. A transfer step of transferring the toner image onto the surface of the transfer material to obtain a transfer toner image, and a fixing step of fixing the transfer toner image, wherein the toner aggregates resin particles having a core-shell structure. In the obtained toner for developing an electrostatic charge image, the resin constituting the core and the shell is an amorphous resin, and the glass transition temperature of the resin constituting the core and the glass transition temperature of the resin constituting the shell are 20 The fixing step is a step of fixing the toner image by heating without heating and containing an acidic or basic polar group or an alcoholic hydroxyl group in the resin constituting the shell. The Image forming method according to symptoms is disclosed.

JP 2005-274964 A JP 2007-93637 A JP 2009-53318 A

  An object of the present invention is to provide a toner for developing an electrostatic image that is excellent in heat storage properties while suppressing a decrease in low-temperature fixability.

The above problems are solved by the following specific means.
That is, the invention according to claim 1 includes an amorphous polyester resin, core particles composed of a crystalline polyester resin (A) having a weight average molecular weight of 7,500 or more and 40,000 or less, and a weight average molecular weight. A toner for developing an electrostatic charge image, comprising: a shell layer composed of a crystalline polyester resin (B) of 50,000 to 150,000, and particles having a core / shell structure.

  The invention according to claim 2 is characterized in that the crystalline polyester resin (A) constituting the core particle has an acid value of 3 mgKOH / g or more and 7.5 mgKOH / g or less, and the crystallinity constituting the shell layer. The toner for developing an electrostatic charge image according to claim 1, wherein the acid value of the polyester resin (B) is 10 mgKOH / g or more and 20 mgKOH / g or less.

  In the invention according to claim 3, in the particles having the core-shell structure, the ratio of the crystalline polyester resin (A) to the crystalline polyester resin (B) is (A) :( B The toner for developing an electrostatic charge image according to claim 1, wherein: 80:20 to 30:70.

  The invention according to claim 4 is a resin in which the crystalline polyester resin (A) and the crystalline polyester resin (B) have a repeating unit derived from the same monomer. 2. The toner for developing an electrostatic charge image according to item 1.

  In the invention according to claim 5, the melting temperatures of the crystalline polyester resin (A) and the crystalline polyester resin (B) are both 60 ° C. or higher and 95 ° C. or lower. The toner for developing an electrostatic image described in 1.

  A sixth aspect of the present invention is an electrostatic charge image developer containing the electrostatic charge image developing toner according to any one of the first to fifth aspects.

  A seventh aspect of the invention is a toner cartridge that accommodates the electrostatic image developing toner according to any one of the first to fifth aspects and is detachable from the image forming apparatus.

  The invention according to claim 8 contains the electrostatic charge image developer according to claim 6 and develops the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer. And a process cartridge that is detachably attached to the image forming apparatus.

  According to a ninth aspect of the invention, there is provided an image carrier, a charging unit for charging the surface of the image carrier, an electrostatic charge image forming unit for forming an electrostatic image on the charged surface of the image carrier, and A developing unit that contains the electrostatic charge image developer according to claim 6 and that develops the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic image developer; and a surface of the image carrier. An image forming apparatus comprising: transfer means for transferring the toner image formed on the surface of the recording medium; and fixing means for fixing the toner image transferred to the surface of the recording medium.

  The invention according to claim 10 is a charging step for charging the surface of the image carrier, an electrostatic charge image forming step for forming an electrostatic image on the charged surface of the image carrier, and an electrostatic charge according to claim 6. A development step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image by an image developer, and a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium And a fixing step of fixing the toner image transferred to the surface of the recording medium.

According to the first aspect of the present invention, the toner for developing an electrostatic charge image is excellent in thermal storage properties while suppressing a decrease in low-temperature fixability as compared with the case where particles composed of one kind of crystalline polyester resin are used. Is provided.
According to the invention which concerns on Claim 2, it suppresses the fall of low temperature fixability compared with the case where the acid value of crystalline polyester resin (A) and crystalline polyester resin (B) remove | deviates from said range. In addition, an electrostatic charge image developing toner having excellent heat storage properties is provided.
According to the invention of claim 3, while suppressing a decrease in low-temperature fixability as compared with the case where the ratio of the crystalline polyester resin (A) and the crystalline polyester resin (B) is out of the above range. Provided is a toner for developing an electrostatic image having excellent thermal storage properties.
According to the invention which concerns on Claim 4, compared with the case where crystalline polyester resin (A) and crystalline polyester resin (B) are resin which has a repeating unit derived from a different monomer, low temperature fixability An electrostatic charge image developing toner having excellent resistance is provided.
According to the invention of claim 5, the electrostatic charge image is excellent in low-temperature fixability as compared with the case where the melting temperatures of the crystalline polyester resin (A) and the crystalline polyester resin (B) are both out of the above ranges. A developing toner is provided.

According to the sixth aspect of the present invention, heat storage properties can be achieved while suppressing a decrease in low-temperature fixability as compared with the case where the toner for developing an electrostatic charge image using particles made of one kind of crystalline polyester resin is included. An electrostatic charge image developer that is excellent in performance is provided.
According to the invention of claim 7, the toner for developing an electrostatic charge image is excellent in heat storage property while suppressing a decrease in low-temperature fixability as compared with the case of using particles made of one kind of crystalline polyester resin. A toner cartridge is provided.
According to the eighth aspect of the present invention, heat storage properties can be achieved while suppressing a decrease in low-temperature fixability as compared with the case where the toner for developing an electrostatic charge image using particles made of one kind of crystalline polyester resin is included. A process cartridge containing an electrostatic charge image developer excellent in performance is provided.
According to the ninth aspect of the present invention, heat storage properties can be achieved while suppressing a decrease in low-temperature fixability as compared with a case where toner for developing an electrostatic charge image using particles made of one kind of crystalline polyester resin is included. An image forming apparatus using an electrostatic charge image developer excellent in the above is provided.
According to the tenth aspect of the present invention, compared with the case where the toner for developing an electrostatic charge image using particles made of one kind of crystalline polyester resin is included, the heat storage property is suppressed while the deterioration of the low temperature fixability is suppressed. An image forming method using an electrostatic charge image developer excellent in the above is provided.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the process cartridge of this embodiment.

  Hereinafter, embodiments of an electrostatic image developing toner, an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method of the present invention will be described in detail.

<Toner for electrostatic image development>
The toner for developing an electrostatic charge image according to this embodiment (hereinafter sometimes referred to as the toner according to this embodiment) has an amorphous polyester resin and a weight average molecular weight of 7,500 or more and 40,000 or less. It has a core-shell structure composed of core particles composed of a crystalline polyester resin (A) and a shell layer composed of a crystalline polyester resin (B) having a weight average molecular weight of 50,000 to 150,000. An electrostatic charge image developing toner containing particles.
The toner according to the exemplary embodiment includes an amorphous polyester resin and particles having the core / shell structure as a binder resin. Such a binder resin is contained in toner particles, and the toner according to the present embodiment is composed of toner particles containing an amorphous polyester resin and particles having a core / shell structure alone. Alternatively, it may be configured to include such toner particles and an external additive that is externally added as necessary.

Since the toner according to the exemplary embodiment has the above-described configuration, the toner according to the exemplary embodiment has excellent heat storage properties while suppressing a decrease in low-temperature fixability.
The reason why such an effect can be obtained is as follows.
As one means for achieving low-temperature fixability during image formation, a method in which both a crystalline polyester resin and an amorphous polyester resin are contained in a toner has been adopted.
First, the function of each resin will be described. Amorphous polyester resin works effectively to improve the basic properties of the toner, such as toner strength, chargeability, and image strength, but tends to be disadvantageous for low-temperature fixability. On the other hand, the crystalline polyester resin effectively works to improve the low-temperature fixability, but tends to be disadvantageous for basic toner properties such as toner strength, chargeability, and image strength. This is because amorphous polyester resin is tough as a polymer, so it is easy to improve the basic properties of the toner, but on the other hand, the viscoelasticity is not easily lowered in the resin melting behavior during heating, and low temperature fixability is realized. It is presumed that this is because the crystalline polyester resin has a characteristic that it is difficult, and the crystalline polyester resin has a low viscoelasticity when heated, but has a characteristic that the strength and toughness as a polymer are low.
Therefore, there is a known method that uses both crystalline polyester resin and amorphous polyester resin to achieve both low-temperature fixability and heat storage. However, the compatibility between crystalline polyester resin and amorphous polyester resin is known. If good, the crystalline polyester resin may plasticize the amorphous polyester resin. In that case, there is a case where the onset temperature of the plasticized amorphous polyester resin is lowered and it is difficult to ensure the heat storage property.

On the other hand, the toner according to this embodiment has a dispersion system in which particles having a core / shell structure are dispersed as a dispersoid (domain) in a dispersion medium (matrix) made of an amorphous polyester resin.
In this dispersion system, in the particles having the core-shell structure in the present embodiment, the shell layer is composed of a crystalline polyester resin (B) having a weight average molecular weight of 50,000 to 150,000. Such a relatively high molecular weight crystalline polyester resin (B) has a high viscosity even at a temperature equal to or higher than the melting temperature of the resin, and is hardly compatible with the amorphous polyester resin. . Therefore, it is considered that a decrease in the onset temperature of the amorphous polyester resin caused by the compatibility between the crystalline polyester resin and the amorphous polyester resin as a dispersion medium is suppressed. As a result, the toner containing particles having such a shell layer has excellent heat storage properties.
The core particles in the particles having a core-shell structure are crystalline polyester resins (A) having a weight average molecular weight of 7,500 or more and 40,000 or less lower than the crystalline polyester resin (B) constituting the shell layer. It is composed of Such a crystalline polyester resin (A) can be easily eluted by heat and pressure from a fixing device during fixing. Further, the shell layer covering the core particles is melted by heat and pressure by the fixing device, and does not hinder the elution of the crystalline polyester resin (A) into the amorphous polyester resin. That is, at the time of fixing, the core / shell structure of the crystalline polyester resin (A) and the crystalline polyester resin (B) is broken, and the eluted crystalline polyester resin (A) is plasticized of the amorphous polyester resin as a dispersion medium. To promote. For this reason, it is presumed that the toner containing particles having a core / shell structure in this embodiment can maintain low-temperature fixability.

  Hereinafter, the toner particles and the external additive constituting the toner according to the exemplary embodiment will be sequentially described.

[Toner particles]
The toner particles include a binder resin as described above and, if necessary, a colorant, a release agent, and other additives.
Hereinafter, each of these components will be described.

(Binder resin)
In the present embodiment, the binder resin includes an amorphous polyester resin and particles having the core-shell structure described above.

The “crystallinity” of the resin means that it has a clear endothermic peak in differential scanning calorimetry (DSC) rather than a stepwise endothermic amount change. Specifically, the temperature rise rate is 10 (° C. / Min) indicates that the half-value width of the endothermic peak is 10 ° C. or less.
On the other hand, “amorphous” of the resin means that the half width exceeds 10 ° C., shows a stepwise endothermic change, or does not show a clear endothermic peak.

-Particles having a core-shell structure-
The particles having a core-shell structure in the present embodiment (hereinafter, sometimes simply referred to as “core-shell particles”) have a weight average molecular weight of 7,500 or more and 40,000 or less crystalline polyester resin (A). And a shell layer composed of a crystalline polyester resin (B) having a weight average molecular weight of 50,000 or more and 150,000 or less.
That is, the core / shell particles have a structure in which a shell layer made of a crystalline polyester resin (B) having a higher molecular weight than the core particles made of the crystalline polyester resin (A) is provided.
Here, the core particles may be composed only of the crystalline polyester resin (A), and the shell layer may be composed only of the crystalline polyester resin (B), but the effects in the present embodiment are not impaired. In the range, any component other than the crystalline polyester resin may be contained in a range of 50% by mass or less. Examples of optional components include crystalline resins other than polyester (for example, release agent WAX), amorphous resins (for example, amorphous polyester resin, poly (styrene-acrylic acid)) resin, polystyrene resins, and the like. It is done.
Hereinafter, the crystalline polyester resin used for the core / shell particles will be described.

-Crystalline polyester resin-
Examples of the crystalline polyester resin include a polycondensate of a polyvalent carboxylic acid and a polyhydric alcohol. In addition, as a crystalline polyester resin, a commercial item may be used and what was synthesize | combined may be used.
Here, since the crystalline polyester resin easily forms a crystal structure, a polycondensate using a polymerizable monomer having a linear aliphatic group is preferable to a polymerizable monomer having an aromatic group.

Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (for example, oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decane. Dicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acid (for example, phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6) -Dibasic acids such as dicarboxylic acids), their anhydrides, or lower (for example, having 1 to 5 carbon atoms) alkyl esters.
The polyvalent carboxylic acid may be used in combination with a dicarboxylic acid or a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of the trivalent carboxylic acid include aromatic carboxylic acids (for example, 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), these Anhydrides thereof, or lower (for example, having 1 to 5 carbon atoms) alkyl esters thereof.
As the polyvalent carboxylic acid, a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond may be used in combination with these dicarboxylic acids.
Polyvalent carboxylic acid may be used individually by 1 type, and may use 2 or more types together.

Examples of the polyhydric alcohol include aliphatic diols (for example, linear aliphatic diols having a main chain portion having 7 to 20 carbon atoms). Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18- Examples include octadecanediol and 1,14-eicosandecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable as the aliphatic diol.
The polyhydric alcohol may be used in combination with a diol and a trivalent or higher alcohol having a crosslinked structure or a branched structure. Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like.
A polyhydric alcohol may be used individually by 1 type, and may use 2 or more types together.

  Here, the polyhydric alcohol may have an aliphatic diol content of 80 mol% or more, and preferably 90 mol% or more.

  The crystalline polyester resin in the present embodiment may be manufactured by any known manufacturing method, for example, similarly to the manufacturing of the amorphous polyester described later.

In this embodiment, the crystalline polyester resin (A) constituting the core particles has a weight average molecular weight (Mw) of 7,500 or more and 40,000 or less, preferably 7,500 or more and 30,000 or less. 000 or more and 25,000 or less are more preferable.
When the molecular weight of the crystalline polyester resin (A) is larger than 40,000, there are cases where the low-temperature fixability cannot be achieved, and when it is smaller than 7,500, there are cases where the heat storage property is deteriorated.

The weight average molecular weight (Mw) of the crystalline polyester resin (B) constituting the shell layer is from 50,000 to 150,000, preferably from 50,000 to 100,000, and from 75,000 to 100. 1,000 or less is more preferable.
When the molecular weight of the crystalline polyester resin (B) is less than 50,000, the heat storage property may be deteriorated. When the molecular weight is greater than 150,000, the low temperature fixability may be deteriorated.

  Further, from the viewpoint of achieving both low-temperature fixability and heat storage stability, the difference between the weight average molecular weight of the crystalline polyester resin (A) and the weight average molecular weight of the crystalline polyester resin (B) is 15,000 or more. 100,000 or less is preferable, and 20,000 or more and 75,000 or less are more preferable.

Here, in this embodiment, the weight average molecular weight and the number average molecular weight of each resin including a crystalline polyester resin are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is performed with a THF solvent using a Tosoh Corporation column, TSKgel SuperHM-M (15 cm), using a Tosoh Corporation HLC-8120GPC as a measuring device.
The weight average molecular weight and the number average molecular weight are calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample from this measurement result.

In addition, in this embodiment, the crystalline polyester resin (A) constituting the core particle has an acid value (AV) of 3 mgKOH / g or more and 7.5 mgKOH / g or less, and the crystalline polyester constituting the shell layer The acid value (AV) of the resin (B) is preferably 10 mgKOH / g or more and 20 mgKOH / g or less.
The acid value of the crystalline polyester resin (A) is more preferably 3 mgKOH / g or more and 6 mgKOH / g or less.
The acid value of the crystalline polyester resin (B) constituting the shell layer is more preferably 10 mgKOH / g or more and 17.5 mgKOH / g or less, and further preferably 10 mgKOH / g or more and 15 mgKOH / g or less.
In general, amorphous polyester resin tends to be more hydrophilic than crystalline polyester resin, and the higher the acid value of crystalline polyester resin, the easier it is to be compatible with amorphous polyester resin. I guess. Therefore, when an amorphous polyester resin, a high acid value crystalline polyester resin, or a low acid value crystalline polyester resin is present, the high acid value crystalline polyester resin acts as a dispersant and has a low acid value. It is presumed that it becomes possible to easily maintain the state in which the crystalline polyester resin is dispersed in the amorphous polyester resin.
Thus, it becomes possible to ensure heat storage property because the acid value of crystalline resin exists in the said range.

Furthermore, from the viewpoint of securing heat storage properties by maintaining the dispersion state, the difference between the acid value of the crystalline polyester resin (A) and the acid value of the crystalline polyester resin (B) is 2.5 mgKOH / g or more and 15 mgKOH / g or less is preferable, and 7.5 mgKOH / g or more and 15 mgKOH / g or less is more preferable.
In this embodiment, the acid value of the crystalline polyester resin is measured according to JIS K-0070-1992.

In this embodiment, the ratio of the crystalline polyester resin (A) constituting the core particles to the crystalline polyester resin (B) constituting the shell layer is (A) :( B) = 80 on a mass basis. Is preferably in the range of 20 to 30:70, more preferably in the range of (A) :( B) = 80: 20 to 40:60, and (A) :( B) = 80: More preferably, it is in the range of 20 to 50:50.
By being in the above range, in the toner, the crystalline polyester is dispersed in the amorphous polyester, and at the time of fixing, the crystalline polyester forming the core portion can effectively plasticize the amorphous polyester. As a result, both the low-temperature fixing property and the heat storage property are excellent.

Furthermore, in this embodiment, the melting temperatures of the crystalline polyester resin (A) constituting the core particles and the crystalline polyester resin (B) constituting the shell layer are both preferably 60 ° C. or higher and 95 ° C. or lower, and 70 More preferably, the temperature is from 95 ° C. to 95 ° C., more preferably from 70 ° C. to 85 ° C.
By being in the above range, it is possible to control the plasticization of the amorphous polyester resin by the crystalline polyester resin, and it is possible to ensure the low temperature fixability and at the same time secure the heat storage property.
The melting temperature is determined from the “melting peak temperature” described in the method for determining the melting temperature of JIS K7121-1987 “Method for measuring the transition temperature of plastic” from the DSC curve obtained by differential scanning calorimetry (DSC).

In this embodiment, the crystalline polyester resin (A) constituting the core particle and the crystalline polyester resin (B) constituting the shell layer are resins having repeating units derived from the same monomer. preferable.
That is, the crystalline polyester resin (A) and the crystalline polyester resin (B) are preferably polycondensates using the same polyvalent carboxylic acid and polyhydric alcohol. More preferably, all are the same.
By doing so, the plasticity of the amorphous polyester resin at the time of fixing is further promoted, and the low temperature fixability is excellent.

-Manufacture of core / shell particles-
The core / shell particles in the present embodiment may form a state in which the surface of the core particles composed of the crystalline polyester resin (A) is coated with the shell layer composed of the crystalline polyester resin (B). If possible, the production method is not particularly limited, and it is produced by a phase inversion emulsification method, a suspension emulsification method, a D phase emulsification method, a pressure emulsification method, a membrane emulsification method or the like.
Especially, it is preferable to manufacture using the phase inversion emulsification method from the point of structural control of a core shell particle, and a particle diameter control.

The production of the core / shell particles using the phase inversion emulsification method will be specifically described below.
Here, the phase inversion emulsification method is a method in which a resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, and a base is added to the organic continuous phase (O phase) to neutralize the water. A method in which a resin (so-called phase inversion) is converted from W / O to O / W by introducing a medium (W phase) to form a discontinuous phase, and the resin is dispersed in the form of particles in an aqueous medium. It is.
When this method is used, by introducing two kinds of resins having different acid values, a resin having a high acid value is likely to be present on the water phase side during phase inversion. It is estimated that the valence resin forms a shell layer.
Specifically, two kinds of resins having different acid values are dissolved in an organic solvent, and then neutralized with an alkali. Thereafter, water is gradually added dropwise with stirring to obtain an emulsion. By removing the organic solvent from the emulsion thus obtained, an emulsion of core / shell particles can be obtained. If necessary, the stability of the emulsion can be increased by adding a surfactant.
Moreover, the particle diameter of the emulsion can adjust the kind, amount, amount of alkali, temperature at the time of dropping water, and the like of the organic solvent.
Furthermore, the thickness of the shell layer of the core / shell particles is determined by the ratio of the core portion to the shell portion and the particle size of the core / shell particles.

  The volume average particle size (D50v) of the core-shell particles obtained as described above is 50 nm or more and 300 nm from the viewpoint of forming a shell layer with an appropriate film thickness and achieving both low-temperature fixability and heat storage properties. The following is preferable, and 100 nm or more and 250 nm or less are more preferable.

In this embodiment, an amorphous polyester resin is used in combination with the core / shell particles described above.
Hereinafter, the amorphous polyester resin used in combination will be described.

-Amorphous polyester resin-
As an amorphous polyester resin, the condensation polymer of polyhydric carboxylic acid and polyhydric alcohol is mentioned, for example. In addition, as an amorphous polyester resin, a commercial item may be used and what was synthesize | combined may be used.

Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (for example, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc. ), Alicyclic dicarboxylic acids (eg, cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (eg, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or lower (eg, Examples thereof include alkyl esters having 1 to 5 carbon atoms. Among these, as polyvalent carboxylic acid, aromatic dicarboxylic acid is preferable, for example.
The polyvalent carboxylic acid may be used in combination with a dicarboxylic acid or a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower (for example, having 1 to 5 carbon atoms) alkyl esters.
Polyvalent carboxylic acid may be used individually by 1 type, and may use 2 or more types together.

Examples of the polyhydric alcohol include aliphatic diols (for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butane diol, hexane diol, neopentyl glycol, etc.), alicyclic diols (for example, cyclohexane diol, cyclohexane diol). Methanol, hydrogenated bisphenol A, and the like) and aromatic diols (for example, ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, as the polyhydric alcohol, for example, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.
As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked structure or a branched structure may be used together with the diol. Examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolpropane, and pentaerythritol.
A polyhydric alcohol may be used individually by 1 type, and may use 2 or more types together.

The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50 ° C. or higher and 80 ° C. or lower, and more preferably 50 ° C. or higher and 65 ° C. or lower.
The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, described in the method for determining the glass transition temperature in JIS K7121-1987 “Method for Measuring Transition Temperature of Plastic”. It is determined by “extrapolated glass transition start temperature”.

The weight average molecular weight (Mw) of the amorphous polyester resin is preferably from 5,000 to 1,000,000, more preferably from 7,000 to 500,000.
The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2000 or more and 100,000 or less.
The molecular weight distribution Mw / Mn of the amorphous polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.

The amorphous polyester resin in the present embodiment may be manufactured by any known manufacturing method. Specifically, for example, it is produced by a method in which the polymerization temperature is set to 180 ° C. or higher and 230 ° C. or lower, the pressure in the reaction system is reduced as necessary, and the reaction is performed while removing water and alcohol generated during the condensation. .
In addition, when the monomer of the raw material is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added and dissolved as a solubilizing agent. In this case, the polycondensation reaction is performed while distilling off the solubilizer. If a monomer with poor compatibility is present in the copolymerization reaction, the monomer with poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polymerized together with the main component. It is good to condense.

  In the present embodiment, from the viewpoint of achieving both low-temperature fixability and heat storage properties, the amount ratio of the core / shell particles and the amorphous polyester resin described above is: core / shell particles: amorphous polyester resin = 2. The range from 5: 97.5 to 35:65 is preferred, the range from 5:95 to 25:75 is more preferred, and the range from 10:90 to 25:75 is even more preferred.

In the present embodiment, in addition to the above-described core / shell particles and amorphous polyester resin, other resins may be used as the binder resin as long as the effects are not impaired.
Examples of other resins include styrenes (for example, styrene, parachlorostyrene, α-methylstyrene, etc.), (meth) acrylic acid esters (for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, N-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (for example, , Acrylonitrile, methacrylonitrile, etc.), vinyl ethers (eg, vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (eg, vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (eg, Ethylene, propylene, a homopolymer of a monomer such as butadiene) and the like, or a vinyl-based resin composed of these monomers with two or more combinations copolymer.
Furthermore, other binder resins include, for example, epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, non-vinyl resins such as modified rosins, mixtures of these with the vinyl resins, or these And a graft polymer obtained by polymerizing a vinyl monomer in the presence of.
These other binder resins may be used alone or in combination of two or more.

  The content of the binder resin is, for example, preferably 40% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, and more preferably 60% by mass to 85% by mass with respect to the entire toner particles. Further preferred.

(Coloring agent)
Examples of the colorant include carbon black, chrome yellow, hansa yellow, benzidine yellow, sren yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, brilliant. Carmine 6B, Dupont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Pigment Red, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Pigment Blue, Phthalocyanine Green, Various pigments such as malachite green oxalate, or acridine series, xanthene series, azo series Various dyes such as benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole Can be mentioned.
A colorant may be used individually by 1 type and may use 2 or more types together.

  As the colorant, a surface-treated colorant may be used as necessary, or it may be used in combination with a dispersant. A plurality of colorants may be used in combination.

  The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 15% by mass or less with respect to the entire toner particles.

(Release agent)
Examples of mold release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; ester types such as fatty acid esters and montanic acid esters Wax; and the like. The release agent is not limited to this.

The melting temperature of the release agent is preferably 50 ° C. or higher and 110 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower.
The melting temperature is determined from the “melting peak temperature” described in the method for determining the melting temperature of JIS K7121-1987 “Method for measuring the transition temperature of plastic” from the DSC curve obtained by differential scanning calorimetry (DSC).

  The content of the release agent is, for example, preferably 1% by mass to 20% by mass and more preferably 5% by mass to 15% by mass with respect to the entire toner particles.

(Other additives)
Examples of other additives include known additives such as a magnetic material, a charge control agent, and inorganic powder. These additives are contained in the toner particles as internal additives.

(Toner particle characteristics, etc.)
The toner particles may be toner particles having a single layer structure, or toner particles having a so-called core / shell structure composed of a core (core particle) and a coating layer (shell layer) covering the core. May be.
Here, the core / shell structure toner particles include, for example, a core portion including a binder resin and, if necessary, other additives such as a colorant and a release agent, and a binder resin. It is good to be comprised with the comprised coating layer.

  The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 3 μm or more and 8 μm or less.

The various average particle diameters and various particle size distribution indexes of the toner particles are measured using Coulter Multisizer II (manufactured by Beckman-Coulter), and the electrolyte is measured using ISOTON-II (manufactured by Beckman-Coulter). The
In the measurement, 0.5 mg to 50 mg of a measurement sample is added as a dispersant to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate). This is added to 100 ml or more and 150 ml or less of the electrolytic solution.
The electrolyte in which the sample is suspended is dispersed for 1 minute with an ultrasonic disperser, and the particle size distribution of particles having a particle size in the range of 2 μm to 60 μm is measured using a 100 μm aperture with a Coulter Multisizer II. taking measurement. The number of particles to be sampled is 50,000.
A cumulative distribution is drawn from the smaller diameter side to the particle size range (channel) divided based on the measured particle size distribution, and the cumulative particle size of 16% is the volume particle size D16v. D16p, a particle size that is 50% cumulative is defined as a volume average particle size D50v, a cumulative number average particle size D50p, and a particle size that is 84% cumulative is defined as a volume particle size D84v and a number particle size D84p.
Using these, the volume average particle size distribution index (GSDv) is calculated as (D84v / D16v) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D84p / D16p) ^1/2 .

(External additive)
Examples of the external additive include inorganic particles. As the inorganic particles, SiO ₂ , TiO ₂ , Al ₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, CaO, K ₂ O, Na ₂ O, ZrO ₂ , CaO. _{SiO 2, K 2 O · (} TiO 2) n, Al 2 O 3 · 2SiO 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 , and the like.

The surface of the inorganic particles as an external additive is preferably subjected to a hydrophobic treatment. The hydrophobic treatment is performed, for example, by immersing inorganic particles in a hydrophobic treatment agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together.
The amount of the hydrophobizing agent is usually, for example, 1 part by mass or more and 10 parts by mass with respect to 100 parts by mass of the inorganic particles.

  Examples of external additives include resin particles (resin particles such as polystyrene, PMMA, and melamine resin), cleaning activators (for example, metal salts of higher fatty acids typified by zinc stearate, particles of a fluorine-based high molecular weight substance), and the like. Can be mentioned.

  The external addition amount of the external additive is, for example, preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2.0% by mass or less with respect to the toner particles.

[Toner Production Method]
Next, a toner manufacturing method according to this embodiment will be described.
In the toner according to the present embodiment, after producing toner particles containing the above-described amorphous polyester resin and core / shell particles, an external additive is externally added to the toner particles as necessary. It is obtained with.
Hereinafter, a toner manufacturing method will be described in detail.

The toner particles may be produced by any of a dry production method (for example, a kneading pulverization method) and a wet production method (for example, an aggregation coalescence method, a suspension polymerization method, a dissolution suspension method, etc.). The production method of the toner particles is not particularly limited, and a known production method is adopted.
Among these, it is preferable to obtain toner particles by an aggregation and coalescence method.

  Specifically, for example, when toner particles are produced by an aggregation and coalescence method, a step of preparing a resin particle dispersion in which resin particles serving as a binder resin are dispersed (resin particle dispersion preparation step), and resin particles Step of agglomerating resin particles (other particles as required) to form aggregated particles in the dispersion (if necessary after mixing with other particle dispersions) (aggregated particle formation) Step) and heating the agglomerated particle dispersion in which the agglomerated particles are dispersed, and fusing and coalescing the agglomerated particles to form toner particles (fusing and coalescing step). Manufacturing.

Details of each step will be described below.
In the following description, a method of obtaining toner particles containing a colorant and a release agent will be described. However, the colorant and the release agent are used as necessary. Of course, you may use other additives other than a coloring agent and a mold release agent.

-Preparation step of resin particle dispersion-
First, together with a resin particle dispersion in which resin particles to be a binder resin are dispersed, for example, a colorant particle dispersion in which colorant particles are dispersed and a release agent dispersion in which release agent particles are dispersed are prepared. .

Here, the crystalline polyester resin particle dispersion is preferably prepared by the phase inversion emulsification method described above. In this embodiment, as described above, by applying the crystalline polyester resin (A) and the crystalline polyester resin (B) to the phase inversion emulsification method, a dispersion of core / shell particles with the crystalline polyester resin is obtained. It is done.
Similarly, in the case of an amorphous polyester resin particle dispersion, it is preferable to prepare the amorphous polyester resin by subjecting it to a phase inversion emulsification method.

Examples of the dispersion medium used for the resin particle dispersion include an aqueous medium.
Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together.

Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol And nonionic surfactants such as polyphenols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, an anionic surfactant and a cationic surfactant are particularly mentioned. The nonionic surfactant may be used in combination with an anionic surfactant or a cationic surfactant.
Surfactant may be used individually by 1 type and may use 2 or more types together.

The volume average particle diameter of the resin particles dispersed in the resin particle dispersion is, for example, preferably 0.01 μm to 1 μm, more preferably 0.08 μm to 0.8 μm, and further preferably 0.1 μm to 0.6 μm. preferable.
In addition, the volume average particle diameter of the resin particles is based on the particle size range (channel) divided by using the particle size distribution obtained by measurement with a laser diffraction particle size distribution measuring apparatus (for example, LA-700 manufactured by Horiba, Ltd.). The cumulative distribution is drawn from the small particle diameter side with respect to the volume, and the particle diameter that becomes 50% cumulative with respect to all the particles is measured as the volume average particle diameter D50p. The volume average particle size of particles in other dispersions is also measured in the same manner.

  As content of the resin particle contained in a resin particle dispersion liquid, 5 to 50 mass% is preferable, for example, and 10 to 40 mass% is more preferable.

  In addition, similarly to resin particle dispersion, for example, a colorant dispersion and a release agent dispersion are also prepared. In other words, regarding the volume average particle size of the particles in the resin particle dispersion, the dispersion medium, the dispersion method, and the content of the particles, the colorant particles dispersed in the colorant dispersion and the release agent dispersed in the release agent dispersion are used. The same applies to the mold agent particles.

-Aggregated particle formation process-
Next, the colorant particle dispersion and the release agent dispersion are mixed together with the resin particle dispersion.
Then, in the mixed dispersion, resin particles, colorant particles, and release agent particles are hetero-aggregated to have resin particles, colorant particles, and release agent particles having a diameter close to the diameter of the target toner particles. Aggregated particles are formed.

Specifically, for example, the flocculant is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to acidic (for example, the pH is 2 or more and 5 or less), and a dispersion stabilizer is added as necessary. The resin particles are heated to a glass transition temperature (specifically, for example, the glass transition temperature of the resin particles −30 ° C. or more and the glass transition temperature −10 ° C. or less), and the particles dispersed in the mixed dispersion liquid are aggregated. , Forming aggregated particles.
In the agglomerated particle forming step, for example, the aggregating agent is added at room temperature (for example, 25 ° C.) while stirring the mixed dispersion with a rotary shearing homogenizer, and the pH of the mixed dispersion is acidic (for example, the pH is 2 or more and 5 or less). ), And after adding a dispersion stabilizer as necessary, the heating may be performed.

Examples of the flocculant include surfactants having a polarity opposite to that of the surfactant used as the dispersant added to the mixed dispersion, for example, inorganic metal salts and divalent or higher-valent metal complexes. In particular, when a metal complex is used as the flocculant, the amount of the surfactant used is reduced, and the charging characteristics are improved.
If necessary, an additive that forms a complex or a similar bond with the metal ion of the flocculant may be used. As this additive, a chelating agent is preferably used.

Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and inorganic substances such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include metal salt polymers.
A water-soluble chelating agent may be used as the chelating agent. Examples of the chelating agent include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid, iminodiacid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), and the like.
As addition amount of a chelating agent, 0.01 mass part or more and 5.0 mass part or less are preferable with respect to 100 mass parts of resin particles, for example, and 0.1 mass part or more and less than 3.0 mass parts are more preferable.

-Fusion / unification process-
Next, the aggregated particle dispersion in which the aggregated particles are dispersed is heated to, for example, a glass transition temperature or higher of the resin particles (for example, a temperature of 10 to 30 ° C. higher than the glass transition temperature of the resin particles). Are fused and united to form toner particles.

Through the above steps, toner particles are obtained.
In addition, after obtaining the aggregated particle dispersion liquid in which the aggregated particles are dispersed, the aggregated particle dispersion liquid and the resin particle dispersion liquid in which the resin particles are dispersed are further mixed, and the resin particles are further added to the surface of the aggregated particles. A process of aggregating to adhere to form second aggregated particles, and heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and coalesce the second aggregated particles. The toner particles may be manufactured through a step of forming toner particles having a core / shell structure.

Here, after completion of the fusion / unification process, toner particles formed in the solution are dried through a known washing process, solid-liquid separation process, and drying process to obtain toner particles.
In the washing step, it is preferable to sufficiently carry out substitution washing with ion-exchanged water from the viewpoint of chargeability. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration, etc. are preferably performed from the viewpoint of productivity. Also, the drying process is not particularly limited, but from the viewpoint of productivity, freeze drying, flash jet drying, fluidized drying, vibration fluidized drying, or the like is preferably performed.

  The toner according to the exemplary embodiment is manufactured, for example, by adding an external additive to the obtained dry toner particles and mixing them. Mixing is preferably performed by, for example, a V blender, a Henschel mixer, a Ladyge mixer, or the like. Furthermore, if necessary, coarse toner particles may be removed using a vibration classifier, a wind classifier, or the like.

<Electrostatic image developer>
The electrostatic charge image developer according to the exemplary embodiment includes at least the toner according to the exemplary embodiment.
The electrostatic image developer according to this embodiment may be a one-component developer including only the toner according to this embodiment, or may be a two-component developer mixed with the toner and a carrier.

There is no restriction | limiting in particular as a carrier, A well-known carrier is mentioned. As a carrier, for example, a coated carrier in which the surface of a core made of magnetic powder is coated with a coating resin; a magnetic powder dispersion type carrier in which magnetic powder is dispersed and mixed in a matrix resin; a porous magnetic powder is impregnated with a resin Resin impregnated type carriers; and the like.
Note that the magnetic powder-dispersed carrier and the resin-impregnated carrier may be a carrier in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

  Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

  Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

Examples of the coating resin and matrix resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer. Examples thereof include a polymer, a straight silicone resin containing an organosiloxane bond or a modified product thereof, a fluororesin, a polyester, a polycarbonate, a phenol resin, and an epoxy resin.
Note that the coating resin and the matrix resin may contain other additives such as a conductive material.

Here, in order to coat the surface of the core material with the coating resin, a method of coating with a coating layer forming solution obtained by dissolving the coating resin and, if necessary, various additives in an appropriate solvent may be mentioned. The solvent is not particularly limited, and may be selected in consideration of the coating resin to be used, coating suitability, and the like.
Specific resin coating methods include a dipping method in which the core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the surface of the core material, and a state in which the core material is suspended by flowing air. Examples thereof include a fluidized bed method in which a coating layer forming solution is sprayed, a kneader coater method in which a carrier core material and a coating layer forming solution are mixed in a kneader coater, and the solvent is removed.

  The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner: carrier = 1: 100 to 30: 100, and more preferably 3: 100 to 20: 100.

<Image Forming Apparatus / Image Forming Method>
The image forming apparatus / image forming method according to the present embodiment will be described.
The image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the surface of the charged image carrier, and an electrostatic charge. Development means for containing an image developer and developing the electrostatic image formed on the surface of the image carrier as a toner image with the electrostatic image developer, and the toner image formed on the surface of the image carrier as a recording medium Transfer means for transferring to the surface of the recording medium, and fixing means for fixing the toner image transferred to the surface of the recording medium. The electrostatic charge image developer according to this embodiment is applied as the electrostatic charge image developer.

  In the image forming apparatus according to this embodiment, a charging process for charging the surface of the image carrier, an electrostatic charge image forming process for forming an electrostatic image on the surface of the charged image carrier, and an electrostatic charge according to this embodiment. A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with an image developer; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of the recording medium; An image forming method (an image forming method according to the present embodiment) including a fixing step of fixing the toner image transferred onto the surface of the recording medium is performed.

The image forming apparatus according to the present embodiment is a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image carrier to a recording medium; the toner image formed on the surface of the image carrier is transferred to an intermediate transfer member An intermediate transfer type apparatus that primarily transfers the toner image transferred to the surface of the intermediate transfer body and then secondary transfer the toner image to the surface of the recording medium; after the toner image is transferred, the surface of the image carrier before charging is cleaned. An apparatus provided with a cleaning unit; a known image forming apparatus such as an apparatus provided with a charge removing unit that discharges the surface of an image holding member by irradiating a discharge light after charging a toner image and before charging is applied.
In the case of an intermediate transfer type apparatus, the transfer means includes, for example, an intermediate transfer body on which a toner image is transferred to the surface, and a primary transfer that primarily transfers the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body. And a secondary transfer unit that secondarily transfers the toner image transferred onto the surface of the intermediate transfer member onto the surface of the recording medium.

  In the image forming apparatus according to the present embodiment, for example, the part including the developing unit may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge that accommodates the electrostatic charge image developer according to this embodiment and includes a developing unit is preferably used.

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto. The main part shown in the figure will be described, and the description of other parts will be omitted.

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to the present embodiment.
The image forming apparatus shown in FIG. 1 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming units (hereinafter sometimes simply referred to as “units”) 10Y, 10M, 10C, and 10K are arranged in parallel at a predetermined distance from each other in the horizontal direction. The units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the image forming apparatus.

Above each of the units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 as an intermediate transfer member is extended through each unit. The intermediate transfer belt 20 is provided by being wound around a drive roll 22 and a support roll 24 that are in contact with the inner surface of the intermediate transfer belt 20 that are spaced apart from each other in the left to right direction in the drawing. The vehicle travels in the direction toward the unit 10K. The support roll 24 is applied with a force in a direction away from the drive roll 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around the support roll 24. An intermediate transfer member cleaning device 30 is provided on the side of the image carrier of the intermediate transfer belt 20 so as to face the drive roll 22.
Further, each of the developing devices (developing means) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K has yellow, magenta, cyan, and black contained in the toner cartridges 8Y, 8M, 8C, and 8K. The toner including the four color toners is supplied.

  Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, here, the first unit that forms a yellow image disposed on the upstream side in the intermediate transfer belt traveling direction. 10Y will be described as a representative. It should be noted that reference numerals with magenta (M), cyan (C), and black (K) are attached to the same parts as those of the first unit 10Y instead of yellow (Y). Description of the units 10M, 10C, and 10K will be omitted.

The first unit 10Y includes a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, a charging roll (an example of a charging unit) 2Y for charging the surface of the photoreceptor 1Y to a predetermined potential, and the charged surface is exposed by a laser beam 3Y based on a color-separated image signal. Then, an exposure device (an example of an electrostatic image forming unit) 3 that forms an electrostatic image, and a developing device (an example of a developing unit) 4Y that develops the electrostatic image by supplying toner charged to the electrostatic image, developed A primary transfer roll 5Y (an example of a primary transfer unit) that transfers a toner image onto the intermediate transfer belt 20, and a photoconductor cleaning device (an example of a cleaning unit) 6Y that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer. Are arranged in order.
The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described.
First, prior to operation, the surface of the photoreceptor 1Y is charged to a potential of −600V to −800V by the charging roll 2Y.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive substrate (for example, volume resistivity at 20 ° C .: 1 × 10 ⁻⁶ Ωcm or less). This photosensitive layer usually has a high resistance (general resin resistance), but has a property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam 3Y. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 in accordance with yellow image data sent from a control unit (not shown). The laser beam 3Y is applied to the photosensitive layer on the surface of the photoreceptor 1Y, whereby an electrostatic charge image having a yellow image pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic charge image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flows. On the other hand, this is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic charge image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic charge image on the photoreceptor 1Y is visualized (developed image) as a toner image by the developing device 4Y.

  In the developing device 4Y, for example, an electrostatic charge image developer containing at least yellow toner and a carrier is accommodated. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged electric charge on the photoreceptor 1Y, and has a developer roll (a developer holding member). Example) is held on. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force from the photoreceptor 1Y toward the primary transfer roll 5Y is applied to the toner image, so that the photoreceptor is exposed. The toner image on 1Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a (+) polarity opposite to the polarity (−) of the toner, and is controlled to +10 μA by the control unit (not shown) in the first unit 10Y, for example.
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the photoreceptor cleaning device 6Y.

Further, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M is also controlled in accordance with the first unit.
Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner. The

  The intermediate transfer belt 20 on which the four color toner images are transferred in multiple ways through the first to fourth units is disposed on the image transfer surface side of the intermediate transfer belt 20, the support roll 24 in contact with the inner surface of the intermediate transfer belt 20. The secondary transfer roll (an example of a secondary transfer unit) 26 is formed to a secondary transfer portion configured. On the other hand, recording paper (an example of a recording medium) P is fed at a predetermined timing into a gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact with each other via a supply mechanism, and the secondary transfer bias is supplied to the support roll. 24. The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P is applied to the toner image, so The toner image is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) for detecting the resistance of the secondary transfer portion, and is voltage-controlled.

Thereafter, the recording paper P is fed into the pressure contact portions (nip portions) of a pair of fixing rolls in a fixing device (an example of a fixing unit) 28, and the toner image is fixed on the recording paper P to form a fixed image.
The fixing device 28 is not particularly limited in heating method, and may be a fixing device in which an electromagnetic induction method is applied to the heating method, for example.

Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, and the like. In addition to the recording paper P, the recording medium may be an OHP sheet.
In order to further improve the smoothness of the image surface after fixing, the surface of the recording paper P is also preferably smooth. For example, coated paper whose surface of plain paper is coated with resin, art paper for printing, etc. are preferably used. Is done.

  The recording paper P on which the color image has been fixed is carried out toward the discharge unit, and a series of color image forming operations is completed.

<Process cartridge / toner cartridge>
The process cartridge according to this embodiment will be described.
The process cartridge according to the present embodiment accommodates the electrostatic image developer according to the present embodiment, and develops the electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer. And a process cartridge that can be attached to and detached from the image forming apparatus.

  Note that the process cartridge according to the present embodiment is not limited to the above-described configuration, and other means such as a developing device and other units such as an image carrier, a charging unit, an electrostatic charge image forming unit, and a transfer unit, if necessary. And at least one selected from the above.

  Hereinafter, an example of the process cartridge according to the present embodiment will be shown, but the present invention is not limited to this. The main part shown in the figure will be described, and the description of other parts will be omitted.

FIG. 2 is a schematic configuration diagram showing a process cartridge according to the present embodiment.
The process cartridge 200 shown in FIG. 2 is provided around the photoconductor 107 and the photoconductor 107 by, for example, a housing 117 provided with an attachment rail 116 and an opening 118 for exposure. A charging roller 108 (an example of a charging unit), a developing device 111 (an example of a developing unit), and a photoconductor cleaning device 113 (an example of a cleaning unit) are integrally combined and held to form a cartridge. Yes.
In FIG. 2, 109 is an exposure device (an example of an electrostatic charge image forming unit), 112 is a transfer device (an example of a transfer unit), 115 is a fixing device (an example of a fixing unit), and 300 is a recording paper (a recording medium). An example).

Next, the toner cartridge according to this embodiment will be described.
The toner cartridge according to the present exemplary embodiment is a toner cartridge that accommodates the toner according to the present exemplary embodiment and is detachable from the image forming apparatus. The toner cartridge contains toner for replenishment to be supplied to the developing means provided in the image forming apparatus.

  The image forming apparatus shown in FIG. 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K are attached and detached, and the developing devices 4Y, 4M, 4C, and 4K are each developing devices (colors). And a toner supply pipe (not shown). Further, when the amount of toner stored in the toner cartridge becomes low, the toner cartridge is replaced.

  Hereinafter, although an Example and a comparative example are given and this embodiment is described in detail in detail, this embodiment is not limited to these Examples at all. Further, “parts” and “%” indicate “parts by mass” and “% by mass” unless otherwise specified.

(Weight average molecular weight)
The molecular weight of the binder resin or the like is determined under the following conditions. GPC uses “HLC-8120GPC (manufactured by Tosoh Corp.)” and two columns use “TSKgel SuperHM-H (6.0 mm ID × 15 cm) manufactured by Tosoh Corp.” as the eluent. Tetrahydrofuran) was used. As experimental conditions, the experiment was conducted using a sample concentration of 0.5%, a flow rate of 0.6 ml / min, a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and an RI detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

(Glass transition temperature and melting temperature)
The glass transition temperature and the melting temperature were measured by differential scanning calorimetry based on JIS K7121-1987. This measurement was performed as follows.
That is, first, a substance to be measured is set in a differential scanning calorimeter (device name: DSC-50 type) manufactured by Shimadzu Corporation equipped with an automatic tangential processing system, liquid nitrogen is set as a cooling medium, and 10 ° C. / Heat from 0 ° C. to 150 ° C. at the rate of temperature rise for 1 minute (first temperature rise process) to obtain the relationship between the temperature (° C.) and the amount of heat (mW), and then at the rate of temperature drop of −10 ° C./minute The mixture was cooled to 0 ° C., and again heated to 150 ° C. at a temperature increase rate of 10 ° C./min (second temperature increase process), and data was collected. In addition, it hold | maintained for 10 minutes each at 0 degreeC and 150 degreeC.
The melting temperature of the mixture of indium and zinc was used for temperature correction of the detection part of the measuring device, and the heat of fusion of indium was used for correction of the amount of heat. The sample was placed in an aluminum pan, and an aluminum pan containing the sample and an empty aluminum pan for control were set.
The glass transition temperature of the toner was defined as the temperature at the intersection of the extension line of the base line and the rising line in the endothermic part of the DSC curve obtained in the first temperature raising process.
The glass transition temperature of the amorphous resin was defined as the glass transition temperature at the intersection of the extension line of the base line and the rising line in the endothermic part of the DSC curve obtained in the second temperature raising process.
Regarding the melting temperature of the crystalline resin and the release agent, the maximum peak temperature among the peaks having an endotherm of 25 J / g or more in the DSC curve obtained in the second temperature raising process was taken as the melting temperature.

(Acid value)
The acid value (AV) was measured as follows. The basic operation conforms to JIS K-0070-1992.
The sample was used after removing the THF-insoluble component of the resin in advance, or a soluble component extracted with a THF solvent by a Soxhlet extractor was used as the sample. 1.5 g of the pulverized sample was precisely weighed, and the sample was placed in a 300 ml beaker, and 100 ml of a toluene / ethanol (4/1) mixture was added and dissolved. Potentiometric titration was performed with an ethanol solution of 0.1 mol / l KOH using an automatic titrator GT-100 (manufactured by Dia Instruments). The amount of KOH solution used at this time is A (ml), a blank is measured, and the amount of KOH solution used at this time is B (ml). From these values, the acid value was calculated by the following formula (1). In the formula (1), w is a precisely weighed sample amount, and f is a factor of KOH.
Acid value (mgKOH / g) = {(A−B) × f × 5.61} / w Formula (1)

<Synthesis of crystalline polyester resin (A-1)>
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,6-hexanediol: 187.1 parts by mass In a reaction vessel equipped with a stirrer, a thermometer, a condenser and a nitrogen gas introduction tube, the monomer component was added. Then, after replacing the inside of the reaction vessel with dry nitrogen gas, 0.3 part of tin dioctanoate was added to 100 parts of the monomer component. After stirring and reacting at 160 ° C. for 3 hours under a nitrogen gas stream, the temperature was further raised to 180 ° C. over 1.5 hours, the pressure inside the reaction vessel was reduced to 3 kPa, and the reaction was performed when the desired molecular weight was reached. Ended. The physical properties of the obtained crystalline polyester resin (A-1) are shown in Table 1.

<Synthesis of Crystalline Polyester Resin (A-2)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,9-nonanediol: A crystalline polyester resin (A-1) in the same manner as in the crystalline polyester resin (A-1) except that 254.6 parts by mass A-2) was obtained. The physical properties of the obtained crystalline polyester resin (A-2) are shown in Table 1.

<Synthesis of crystalline polyester resin (A-3)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,4-butanediol: Except for using 143.3 parts by mass, the same as the crystalline polyester resin (A-1), the crystalline polyester resin ( A-3) was obtained. The physical properties of the obtained crystalline polyester resin (A-3) are shown in Table 1.

<Synthesis of Crystalline Polyester Resin (A-4)>
Monomer component,
-Sebacic acid: 323.6 parts by mass-1,6-hexanediol: The crystalline polyester resin (A-4) is the same as the crystalline polyester resin (A-1) except that it is 252.6 parts by mass. Obtained. The physical properties of the obtained crystalline polyester resin (A-4) are shown in Table 1.

<Synthesis of Crystalline Polyester Resin (A-5)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,6-hexanediol: 18% by mass Crystalline polyester resin (A -5) was obtained. The physical properties of the obtained crystalline polyester resin (A-5) are shown in Table 1.

<Synthesis of Crystalline Polyester Resin (A-6)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,9-nonanediol: crystalline polyester resin (A-1) in the same manner as the crystalline polyester resin (A-1) except that 253.3 parts by mass A-6) was obtained. The physical properties of the obtained crystalline polyester resin (A-6) are shown in Table 1.

<Synthesis of crystalline polyester resin (A-7)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,4-butanediol: crystalline polyester resin (A-1) in the same manner as in crystalline polyester resin (A-1) except that 143.5 parts by mass A-7) was obtained. The physical properties of the obtained crystalline polyester resin (A-7) are shown in Table 1.

<Synthesis of crystalline polyester resin (A-8)>
Monomer component,
-Fumaric acid: 371.4 parts by mass-1,10-decanediol: The crystalline polyester resin (A-8) is the same as the crystalline polyester resin (A-1) except that it is 554.6 parts by mass. Obtained. The physical properties of the obtained crystalline polyester resin (A-8) are shown in Table 1.

<Synthesis of Crystalline Polyester Resin (A-9)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,6-hexanediol: A crystalline polyester resin (A-1) in the same manner as in the crystalline polyester resin (A-1) except that 175.8 parts by mass A-9) was obtained. The physical properties of the obtained crystalline polyester resin (A-9) are shown in Table 1.

<Synthesis of Crystalline Polyester Resin (A-10)>
Monomer component,
・ Crystalline polyester resin (A-1) except that 1,10-decanedicarboxylic acid: 368.5 parts by mass ・ 1,6-hexanediol: 188.6 parts by mass A-10) was obtained. The physical properties of the obtained crystalline polyester resin (A-10) are shown in Table 1.

<Synthesis of crystalline polyester resin (B-1)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,6-hexanediol: 188.0 parts by mass-trimellitic acid: crystalline polyester resin (A-1 except for 4.75 parts by mass) ) To obtain a crystalline polyester resin (B-1). The physical properties of the obtained crystalline polyester resin (B-1) are shown in Table 1.

<Synthesis of crystalline polyester resin (B-2)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,9-nonanediol: 247.3 parts by mass-Trimellitic acid: 3.14 parts by mass Crystalline polyester resin (A-1 ) To obtain a crystalline polyester resin (B-2). The physical properties of the obtained crystalline polyester resin (B-2) are shown in Table 1.

<Synthesis of crystalline polyester resin (B-3)>
Monomer component,
• 1,10-decanedicarboxylic acid: 368.5 parts by mass • 1,4-butanediol: 143.8 parts by mass • Trimellitic acid: 4.75 parts by mass Crystalline polyester resin (A-1 ) To obtain a crystalline polyester resin (B-3). The physical properties of the obtained crystalline polyester resin (B-3) are shown in Table 1.

<Synthesis of crystalline polyester resin (B-4)>
Monomer component,
-Sebacic acid: 323.6 parts by mass-1,6-hexanediol: 253.7 parts by mass-Trimellitic acid: 6.4 parts by mass The same as the crystalline polyester resin (A-1) A crystalline polyester resin (B-4) was obtained. The physical properties of the obtained crystalline polyester resin (B-4) are shown in Table 1.

<Synthesis of crystalline polyester resin (B-5)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,6-hexanediol: 186.2 parts by mass-Trimellitic acid: 3.94 parts by mass Crystalline polyester resin (A-1 ) To obtain a crystalline polyester resin (B-5). The physical properties of the obtained crystalline polyester resin (B-5) are shown in Table 1.

<Synthesis of Crystalline Polyester Resin (B-6)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,9-nonanediol: 251.2 parts by mass-trimellitic acid: 3.14 parts by mass, except that the crystalline polyester resin (A-1 ) To obtain a crystalline polyester resin (B-6). The physical properties of the obtained crystalline polyester resin (B-6) are shown in Table 1.

<Synthesis of crystalline polyester resin (B-7)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,4-butanediol: 141.3 parts by mass-trimellitic acid: 3.14 parts by mass Except for the crystalline polyester resin (A-1 ) To obtain a crystalline polyester resin (B-7). The physical properties of the obtained crystalline polyester resin (B-7) are shown in Table 1.

<Synthesis of Crystalline Polyester Resin (B-8)>
Monomer component,
-1,10-decanedicarboxylic acid: 368.5 parts by mass-1,6-hexanediol: 192.0 parts by mass-trimellitic acid: 15.76 parts by mass Except for the crystalline polyester resin (A-1 ) To obtain a crystalline polyester resin (B-8). The physical properties of the obtained crystalline polyester resin (B-8) are shown in Table 1.

<Synthesis of Amorphous Polyester Resin (1)>
-Bisphenol A ethylene oxide adduct: 94.9 parts by mass-Bisphenol A propylene oxide adduct: 413.3 parts by mass-Terephthalic acid: 199.4 parts by mass-Tetrapropenyl succinic anhydride: 59.9 parts by mass The monomer component was put into a reaction vessel equipped with a thermometer, a condenser, and a nitrogen gas introduction tube, and the reaction vessel was replaced with dry nitrogen gas, and then tin dioctanoate was reduced to 0 with respect to the total amount of the monomer components. 3% input. The temperature in a nitrogen gas stream was raised to 235 ° C. over 1 hour, reacted for 3 hours, the inside of the reaction vessel was depressurized to 10.0 mmHg, reacted with stirring, and the reaction was terminated when the required molecular weight was reached.
The amorphous polyester resin (1) obtained had a glass transition temperature of 61 ° C., a weight average molecular weight of 13,000, and an acid value of 18 mgKOH / g.

<Amorphous polyester resin (2)>
Monomer component,
-Bisphenol A ethylene oxide adduct: 116.8 parts by mass-Bisphenol A propylene oxide adduct: 317.9 parts by mass-Hydrogenated bisphenol A: 133.1 parts by mass-Terephthalic acid: 199.4 parts by mass-Tetrapropenyl amber Amorphous polyester resin (2) was obtained in the same manner as the amorphous polyester resin (1) except that the acid anhydride was 122.9 parts by mass. The amorphous polyester resin (2) obtained had a glass transition temperature of 63 ° C., a weight average molecular weight of 18000, and an acid value of 13 mgKOH / g.

<Synthesis of Amorphous Polyester Resin (3)>
Monomer component,
-Bisphenol A ethylene oxide adduct: 126.6 parts by mass-Bisphenol A propylene oxide adduct: 551.1 parts by mass-Terephthalic acid: 166.1 parts by mass-Fumaric acid: 46.4 parts by mass-Tetrapropenyl succinic anhydride Product: An amorphous polyester resin (3) was obtained in the same manner as the amorphous polyester resin (1) except that the amount was 106.6 parts by mass. The amorphous polyester resin (3) obtained had a glass transition temperature of 60 ° C., a weight average molecular weight of 20000, and an acid value of 11.5 mgKOH / g.

<Synthesis of Amorphous Polyester Resin (4)>
Monomer component,
-Bisphenol A ethylene oxide adduct: 158.2 parts by mass-Bisphenol A propylene oxide adduct: 258.3 parts by mass-Terephthalic acid: 166.1 parts by mass-Tetrapropenyl succinic anhydride: 50.0 parts by mass Except for the above, an amorphous polyester resin (4) was obtained in the same manner as the amorphous polyester resin (1). The amorphous polyester resin (4) obtained had a glass transition temperature of 59 ° C., a weight average molecular weight of 16000, and an acid value of 16 mgKOH / g.

<Synthesis of Amorphous Polyester Resin (5)>
Monomer component,
-Bisphenol A ethylene oxide adduct: 253.1 parts by mass-Bisphenol A propylene oxide adduct: 413.3 parts by mass-Terephthalic acid: 166.1 parts by mass-Fumaric acid: 46.4 parts by mass-Tetrapropenyl succinic anhydride Product: An amorphous polyester resin (5) was obtained in the same manner as the amorphous polyester resin (1) except that the amount was 106.6 parts by mass. The amorphous polyester resin (5) obtained had a glass transition temperature of 60 ° C., a weight average molecular weight of 18000, and an acid value of 14 mgKOH / g.

<Preparation of core / shell particle dispersion P1>
Crystalline polyester resin (A-1): 70 parts by mass Crystalline polyester resin (B-1): 30 parts by mass The polyester resin is charged into a reaction vessel equipped with a stirrer and a thermometer, and methyl ethyl ketone is further added. 140 parts by mass and 30 parts by mass of isopropyl alcohol were added and heated to 65 ° C. to dissolve the polyester resin. Next, after the temperature was lowered to 60 ° C., 6.4 g of a 10% aqueous ammonia solution was added. While continuing stirring, 300 parts by mass of ion-exchanged water was added dropwise over 3 hours. After dropping, the mixture was cooled to room temperature and stirred for 24 hours under atmospheric release to obtain a core / shell particle dispersion P1.

<Preparation of core / shell particle dispersions P2 to P16, crystalline polyester resin particle dispersion>
The core / shell particle dispersions P2 to P18 were prepared according to the preparation method of the core / shell particle dispersion P1 except that the crystalline polyester resin of the type shown in Table 1 was added at the ratio shown in Table 1. .
In addition, each of the crystalline polyester resin particle dispersions used in Comparative Examples 1 and 2 is the same as the core polyester except that only the crystalline polyester resin (A-1) or (B-1) shown in Table 1 was added. It was prepared according to the method for preparing the shell particle dispersion P1.

<Preparation of amorphous polyester resin particle dispersion>
For the amorphous polyester resins (1) to (5), dispersions of these resin particles were prepared as follows.
That is, the amorphous polyester resin was dissolved in 62.5 parts by mass of methyl ethyl ketone and 25 parts by mass of isopropyl alcohol in the same manner as the preparation of the core / shell particle dispersion P1, except that 100 parts by mass of the amorphous polyester resin was dissolved. A resin dispersion was obtained.

<Preparation of colorant dispersion>
Carbon black (Cabot Japan Co., Ltd., REALAL 330): 200 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC): 33 parts (active ingredient 60%, 10% to colorant) %)
-Ion exchange water: 750 parts When the above components are all charged, the above components are charged into a stainless steel container whose liquid level is 1/3 of the height of the container, and 280 parts of ion exchange water After adding an anionic surfactant and sufficiently dissolving the surfactant, all the pigments are added, and the mixture is stirred using a stirrer until there are no wet pigments, and the remaining ion exchange water is added. The mixture was sufficiently degassed by stirring.
After defoaming, the mixture was dispersed for 10 minutes at 5,000 rpm using a homogenizer (manufactured by IKA, Ultra Tarrax T50), and then defoamed by stirring for one day with a stirrer. After defoaming, the mixture was dispersed again at 6,000 rpm for 10 minutes using a homogenizer, and then stirred for one day and night with a stirrer to defoam.
After defoaming, dispersion was performed at a pressure of 240 MPa using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006). The dispersion was equivalent to 25 passes in terms of the total charge and the processing capacity of the apparatus.
The obtained dispersion was allowed to stand for 72 hours to remove precipitates, and ion exchange water was added to adjust the solid content concentration to 15% to obtain a black colorant dispersion (PDK1). The volume average particle diameter D50v of the particles in this colorant dispersion was 110 nm.

<Preparation of release agent dispersion>
Hydrocarbon wax (manufactured by Nippon Seisaku Co., Ltd., trade name: FNP0090, melting temperature Tw = 90.2 ° C.): 270 parts Anionic surfactant (Taika Co., Ltd., Taca Power BN2060, Active ingredient amount: 60%): 13.5 parts (as active ingredient, 3.0% with respect to release agent)
-Ion-exchanged water: 700 parts The above components were mixed, and the release agent was dissolved at an internal liquid temperature of 120 ° C with a pressure discharge type homogenizer (Gorin homogenizer manufactured by Gorin Inc.), followed by 120 minutes at a dispersion pressure of 5 MPa. The dispersion was treated at 40 MPa for 360 minutes and cooled to obtain a release agent dispersion (DW1). The volume average particle diameter D50v of the particles in this release agent dispersion is 220 nm. Thereafter, ion exchange water was added to prepare a solid content concentration of 20.0%.

[Examples 1 to 12, Comparative Examples 1 to 6]
<Preparation of toner particles>
As a toner component
Crystalline polyester resin: 16.8 parts (core / shell particles or crystalline polyester resin described in Table 1)
Amorphous polyester resin: 39.2 parts (Amorphous polyester resin described in Table 1)
Each dispersion was weighed so that the colorant was 7 parts and the release agent was 9 parts. After each dispersion was charged into a round stainless steel flask, ion-exchanged water was added so that the solid content concentration was 12.5%, and 6.3 parts of a 10% aluminum sulfate aqueous solution was further added. Next, after mixing and dispersing for 10 minutes at 5000 rpm with a homogenizer (manufactured by IKA, Ultra Tarrax T50), the contents in the flask are heated and stirred to 40 ° C. while stirring, and then the temperature is raised at 0.5 ° C. per minute. However, when the particle diameter reached 5.0 μm, the temperature was maintained, and a dispersion corresponding to 28 parts of amorphous polyester resin was added and maintained for 60 minutes. When the obtained contents were observed with an optical microscope, it was confirmed that aggregated particles were generated. After adding 11 parts of ethylenediaminetetraacetic acid (EDTA) tetrasodium salt (manufactured by Kirest Co., Ltd., Kirest 40), an aqueous sodium hydroxide solution was added to adjust the pH to 8, and then the temperature was raised to 82.5. After the temperature was raised, the pH was lowered by 0.05 with nitric acid every 10 minutes, and stirring was continued for 45 minutes. After cooling, the mixture was filtered, sufficiently washed with ion exchange water, and dried to obtain toner particles.

<Production of Toners 1 to 12 and C1 to C6>
To 100 parts of the toner particles obtained above, 1.5 parts of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., RY50) was added and mixed and blended at 13000 rpm for 30 seconds using a sample mill. Thereafter, the particles were sieved with a vibration sieve having an opening of 45 μm to prepare toners 1 to 12 and C1 to C6.

[Evaluation 1: Evaluation of heat storage properties]
2 g of each toner thus obtained was stored for 12 hours in an environment of 55 ° C. and 50 RH%, and the state of the toner after storage was visually observed and evaluated based on the following evaluation criteria.
A: The toner aggregates are hardly seen even after storage at 55 ° C., and the heat storage property is excellent.
B: Toner aggregates are slightly seen after storage at 55 ° C. and slightly inferior in heat storage properties to A.
C: Toner aggregates are observed after storage at 55 ° C. and are inferior to A in heat storage.
D: The toner aggregates after storage at 55 ° C. and does not have heat storage properties.
It should be noted that the above A to C have no practical problem. The results are shown in Table 1.

<Preparation of resin-coated carrier (C)>
Mn-Mg-Sr ferrite particles (average particle size 40 μm): 100 parts Toluene: 14 parts cyclohexyl methacrylate / dimethylaminoethyl methacrylate copolymer (weight ratio 99: 1, Mw 80000): 2.0 parts Carbon Black (VXC72: Cabot): 0.12 parts The above components excluding ferrite particles and glass beads (φ1 mm, the same amount as toluene) were stirred at 1200 rpm for 30 minutes using a sand mill manufactured by Kansai Paint Co., Ltd., and the resin coating layer A forming solution was obtained. Furthermore, this resin coating layer forming solution and ferrite particles were put into a vacuum degassing kneader, decompressed, distilled off toluene and dried to prepare a resin-coated carrier (C).

<Production of developer>
36 parts of the obtained toner and 414 parts of the carrier were put into a 2 liter V blender, stirred for 20 minutes, and then sieved at 212 μm to prepare a developer.

[Evaluation 2: Evaluation of low-temperature fixability]
A DocuCenter IV C3370 manufactured by Fuji Xerox Co., Ltd. was prepared as an image forming apparatus of this embodiment, and an electromagnetic induction type fixing device mounted on the apparatus was modified to control the fixing temperature. The fixing device was modified to be driven by an external drive motor.
Separately, Fuji Xerox A-Color 635 was used as the image forming apparatus, Fuji Xerox J paper was used as the recording medium, and the toner loading was adjusted to 13.5 g / m ² to perform image formation. An unfixed solid image (25 mm × 25 mm) was prepared.
Using a modified DocuCentreIV C3370, the fixing temperature was increased from 100 ° C. to 200 ° C. in steps of 10 ° C., and an unfixed solid image (25 mm × 25 mm) was fixed at a conveyance speed of 175 mm / second for each temperature.
The image surface of the fixed image at each temperature was valley-folded to observe the degree of peeling of the image at the fold, and the width of the paper appearing at the fold as a result of peeling the image was measured. The fixing temperature at which the width was 0.5 mm or less was defined as MFT (minimum fixing temperature, ° C.).
The evaluation criteria are as follows. The results are shown in Table 1.
A: MFT <120 ° C. or less, and exhibits low-temperature fixability.
B: MFT <135 ° C. or lower, slightly lower in low temperature fixability than A
C: MFT <150 ° C. or lower, and low temperature fixability is lower than A.
D: MFT> 150 ° C. or higher and no low temperature fixability.

As shown in Table 1 above, it can be seen that the toner of this example is superior in heat storage property to the toner of the comparative example.
It can also be seen that the developer containing the toner of this example is excellent in low-temperature fixability as compared with the developer of the comparative example.
The toner of Comparative Example 1 contains particles made only of a resin corresponding to the crystalline polyester resin (B). In this toner, the compatibility between the amorphous polyester resin and the crystalline polyester resin is good, and the return of crystallinity is bad. As a result, the heat storage property cannot be ensured. On the other hand, since the molecular weight of the crystalline polyester resin (B) is large, the viscosity of the crystalline polyester resin itself is high, and furthermore, the mixing speed with the amorphous polyester resin is slow, so that the plastic effect on the amorphous polyester resin is high. It cannot be obtained sufficiently and is poor in low-temperature fixability.
Further, the toner of Comparative Example 2 contains particles made of only a resin corresponding to the crystalline polyester resin (A). In this toner, the crystalline polyester resin (A) is easily eluted by the pressure at the time of fixing, and the low-temperature fixability is excellent, but the compatibility with the amorphous polyester resin is good. It is inferior in terms of storability.

1Y, 1M, 1C, 1K photoconductor (an example of an image carrier)
2Y, 2M, 2C, 2K charging roll (an example of charging means)
3. Exposure device (an example of electrostatic charge image forming means)
3Y, 3M, 3C, 3K Laser beams 4Y, 4M, 4C, 4K Developing device (an example of developing means)
5Y, 5M, 5C, 5K primary transfer roll (an example of primary transfer means)
6Y, 6M, 6C, 6K Photoconductor cleaning device (an example of cleaning means)
8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Image forming unit 20 Intermediate transfer belt (an example of an intermediate transfer member)
22 Drive roll 24 Support roll 26 Secondary transfer roll (an example of secondary transfer means)
28 Fixing device (an example of fixing means)
30 Intermediate transfer member cleaning device 107 Photoconductor (an example of an image carrier)
108 Charging roll (an example of charging means)
109 Exposure apparatus (an example of electrostatic charge image forming means)
111 Developing device (an example of developing means)
112 Transfer device (an example of transfer means)
113 photoconductor cleaning device (an example of cleaning means)
115 Fixing device (an example of fixing means)
116 Attachment rail 118 Opening 117 for exposure 117 Case 200 Process cartridge 300 Recording paper (an example of recording medium)
P Recording paper (an example of a recording medium)

Claims (10)

Amorphous polyester resin, and
A core particle composed of a crystalline polyester resin (A) having a weight average molecular weight of 7,500 or more and 40,000 or less and a crystalline polyester resin (B) having a weight average molecular weight of 50,000 or more and 150,000 or less. A toner for developing an electrostatic image, comprising a shell layer and particles having a core / shell structure.   The acid value of the crystalline polyester resin (A) constituting the core particle is 3 mgKOH / g or more and 7.5 mgKOH / g or less, and the acid value of the crystalline polyester resin (B) constituting the shell layer The toner for developing an electrostatic charge image according to claim 1, wherein the toner is 10 mgKOH / g or more and 20 mgKOH / g or less.   In the particles having the core-shell structure, the ratio of the crystalline polyester resin (A) to the crystalline polyester resin (B) is (A) :( B) = 80: 20 to 30: on a mass basis. The electrostatic image developing toner according to claim 1, wherein the toner is 70.   The static polyester according to any one of claims 1 to 3, wherein the crystalline polyester resin (A) and the crystalline polyester resin (B) are resins having repeating units derived from the same monomer. Toner for charge image development.   5. The electrostatic charge image developing according to claim 1, wherein the melting temperatures of the crystalline polyester resin (A) and the crystalline polyester resin (B) are both 60 ° C. or more and 95 ° C. or less. toner.   An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1. Containing the toner for developing an electrostatic charge image according to any one of claims 1 to 5,
A toner cartridge to be attached to and detached from the image forming apparatus. A developing means for containing the electrostatic charge image developer according to claim 6 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer,
A process cartridge attached to and detached from the image forming apparatus. An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Developing means for containing the electrostatic charge image developer according to claim 6 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising: A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer according to claim 6;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
An image forming method comprising: