JP4506614B2 - Toner for developing electrostatic image, method for producing the same, and developer for developing electrostatic image - Google Patents

Description

  The present invention relates to an electrostatic image developing toner suitably used for image formation by electrophotography, a method for producing the same, and an electrostatic image developing developer using the electrostatic image developing toner.

Conventionally, when an image is formed in a copying machine or a laser beam printer, an electrophotographic method is generally used. As a developer used in the electrophotographic method, a two-component developer containing a toner and a carrier and a one-component developer containing a magnetic toner or a nonmagnetic toner are known. The toner used in these developers is usually produced by a kneading and pulverizing method.
In this kneading and pulverization method, a thermoplastic resin or the like is melt-kneaded together with a pigment, a charge control agent, a release agent such as wax, and the like, and after cooling, the melt-kneaded material is finely pulverized and classified to obtain desired toner particles. It is a manufacturing method. The toner particles produced by the kneading and pulverizing method may be further added with inorganic and / or organic fine particles on the surface as necessary for the purpose of improving fluidity and cleaning properties.

In the electrophotographic image forming method, an electrostatic latent image formed on a photoconductor by optical means is developed in a development process, then transferred to a recording medium such as a recording paper in a transfer process, and then a fixing process. In general, the image is fixed on a recording medium such as recording paper by heat and pressure to obtain an image.
In recent years, the technology of electrophotography is rapidly expanding from black and white to full color. Color image formation by full-color electrophotography generally reproduces all colors using four colors obtained by adding black to three primary colors of yellow, magenta, and cyan.

In a general full-color electrophotographic method, first, an original is color-separated into yellow, magenta, cyan, and black, and an electrostatic latent image is formed on the photoconductive layer for each color.
Next, the toner is held on the recording medium through development and transfer processes. Next, the above steps are sequentially performed a plurality of times, and the toner is superimposed on the same recording medium while aligning the positions.
Then, a full color image is obtained by a single fixing process. Color toners used in full-color electrophotography require that multi-color toners are sufficiently mixed in the fixing process. By sufficiently mixing, color reproducibility and transparency of OHP images are improved, and high-quality full-color images. Can be obtained. In order to improve the color mixing property, the color toner is generally formed of a sharp melt low molecular weight resin.

By the way, recently, power saving and high image quality are also demanded in electrophotography. As one of the power saving measures in electrophotography, fixing at a lower temperature is required in order to reduce the amount of energy used during machine operation.
In order to meet such needs, new approaches have been taken from both the toner side and the apparatus side.
As an approach from the toner side, various attempts have been made to lower the fixing temperature of the toner. For example, a method for controlling the viscoelasticity of the toner (see Patent Documents 1 and 2) and a toner using a crystalline resin as a binder resin (see Patent Document 3) have been proposed. In recent years, many toners having a so-called core-shell structure including a core layer and a shell layer covering the core layer have been proposed (see, for example, Patent Document 4).
Among these, in particular, a toner having a core-shell structure is the most useful technique in that not only low-temperature fixability but also other characteristics can be easily balanced.

On the other hand, as an approach from the apparatus side, in order to reduce energy consumption during standby, when the state in which an image is not formed continues (so-called standby), the amount of power supplied to the fixing device is reduced and heated. A device having a function of maintaining the temperature of a heating unit such as a roll at a temperature lower than the temperature at the time of fixing (hereinafter sometimes referred to as “standby power saving function”) is employed.
In an apparatus having such a function, it is necessary to ensure not only power saving but also convenience, and therefore it is preferable to employ a fixing device having a smaller heat capacity as the fixing device (for example, (See Patent Document 5). This is because when the apparatus is used from a state in which the amount of power supplied to the heating unit of the fixing machine is reduced and the temperature of the heating unit is lower than the temperature required for fixing, the temperature of the heating unit is This is because the temperature is instantaneously increased to the temperature required for fixing as the energization starts.

  In such an image forming apparatus having a standby power saving function, in the standby state, the temperature of the heating unit of the fixing device is maintained at a lower temperature than that during fixing in order to reduce power consumption. For this reason, when an image is to be formed from the standby state, electric power is supplied all at once to instantaneously increase the heating means to a fixable temperature, and the heating means is temporarily heated to a temperature higher than a predetermined set temperature. Phenomenon (overshoot) occurs. At this time, when paper is supplied to the fixing device for image formation, heat is taken away by the paper passing through the fixing device, so that the temperature of the fixing device decreases from the overshooted state.

  Further, in addition to the overshoot immediately after the start of image formation as described above (hereinafter, sometimes referred to as “initial overshoot”), even when images are continuously formed, a temperature drop due to paper passing, When the temperature falls below a predetermined temperature, the temperature repeatedly rises due to heating, and therefore periodic overshoots occur (hereinafter sometimes referred to as “steady overshoot”).

When an image is formed, such an overshoot is inevitable. For this reason, the actual fixing temperature varies for each sheet, and a sheet fixed at a temperature higher than the set temperature and a sheet fixed at a temperature lower than the set temperature are mixed. When such temperature fluctuation is significant, the image quality varies. Therefore, the fixing device built in the image forming apparatus is designed so that the temperature fluctuation at the time of image formation falls within a predetermined range so that the image quality does not vary.
JP-A-9-325520 JP-A-8-234480 Japanese Patent Publication No. 4-24702 JP-A-10-123748 JP 2003-84601 A

However, when images are continuously formed from a standby state by an image forming apparatus having a standby power saving function using toner having a core-shell structure excellent in low-temperature fixability, the image formed on each sheet In some cases, the color tone may vary, particularly in the case of multiple colors of secondary colors / tertiary colors.
An object of the present invention is to solve the above problems. That is, the present invention provides a toner for developing an electrostatic charge image that can be fixed at a low temperature and has almost no change in color tone between images even when images are continuously formed. It is an object of the present invention to provide a method and a developer for developing an electrostatic image using the toner for developing an electrostatic image.

In order to achieve the above-mentioned problems, the present inventors have used a toner having a core-shell structure to cause a change in color tone when images are continuously formed by an image forming apparatus having a standby power saving function. First, earnest examination was performed from the viewpoint of the image forming apparatus.
As described above, when the image is formed, the fixing temperature varies due to overshoot. In particular, it is inevitable that the temperature rise due to the initial overshoot generated by heating at a stretch from the low temperature maintained in the standby state will be larger than the temperature rise due to the steady overshoot. Accordingly, the maximum fluctuation width of the fixing temperature when images are continuously formed is the temperature at the time when the temperature due to the initial overshoot has risen completely, and the temperature between the valleys of the steady overshoot and the steady overshoot that are periodically repeated. This is considered to be equivalent to the difference.

  In addition, the fixing device built in the image forming apparatus having the standby power saving function preferably has a small heat capacity in order to enhance the energy saving effect. Further, in a small image forming apparatus, the amount of heat of the fixing device is inevitably required. Becomes smaller. In such a case, the maximum fluctuation width of the fixing temperature described above tends to be larger than the conventional one, but there is a limit to the suppression of such temperature fluctuation. In addition, in recent years, toner capable of low-temperature fixing is being used, and accordingly, the fixing temperature itself is becoming lower.

On the other hand, the conventional toner having a core-shell structure with excellent low-temperature fixability has a sharp melt property. Easy to change rapidly. For this reason, when the maximum fluctuation width of the fixing temperature is further increased, in the toner having the conventional core-shell structure, the color developability depending on the melted state of the toner tends to vary.
As described above, the conventional toner having the core-shell structure has a potential problem that the variation in color developability easily occurs with the energy saving of the apparatus. Not. Therefore, such problems have not been studied so far in the past.

  However, as a result of further diligent investigations by the present inventors, the variation in color developability is a secondary color or tertiary color where the lower the fixing temperature and the greater the heat absorption by the transferred toner image. It was confirmed that the image formation tends to be accelerated in the image formation. Therefore, if such a problem cannot be solved, it is extremely difficult to cope with energy savings that will be further required in the future while ensuring excellent image quality. The present inventors have found the following present invention based on the findings as described above.

That is, the present invention
<1>
In an electrostatic charge image developing toner having a core layer containing a first binder resin and a colorant, and a shell layer containing a second binder resin and covering the core layer,
An electrostatic charge image developing toner characterized by satisfying the following formulas (1) and (2):
Formula (1) 2.0 × 10 ⁵ ≦ G ′ (60) ≦ 4.0 × 10 ⁶
Formula (2) 10 ≦ G ′ (60) / G ′ (80) ≦ 40
[In Formula (1) and Formula (2), G ′ (60) is the electrostatic charge image measured under the conditions of a temperature of 60 ° C., a vibration frequency of 6.28 rad / sec, and a strain amount of 0.01 to 0.5%. This represents the storage elastic modulus (Pa) of the developing toner, and G ′ (80) is the electrostatic charge measured under the conditions of a temperature of 80 ° C., a vibration frequency of 6.28 rad / sec, and a strain amount of 0.01 to 0.5%. The storage elastic modulus (Pa) of the toner for image development is represented. ]

<2>
Two maximum values of tangent loss measured under conditions of vibration frequency of 6.28 rad / sec and strain amount of 0.01 to 0.5% exist in the range of 30 ° C. or higher and 90 ° C. or lower. 1>. The electrostatic charge image developing toner according to 1>.

<3>
The difference (| SPc−SPs |) between the solubility parameter SPc of the first binder resin and the solubility parameter SPs of the second binder resin is in the range of 0.2 to 0.6. <1> or <2>, wherein the toner for developing an electrostatic image is characterized by the above.

<4>
At least a first resin fine particle dispersion made of the first binder resin and having a volume average particle diameter of 1 μm or less dispersed therein and a colorant dispersion containing the colorant dispersed therein are mixed at least. An aggregating step of adding a flocculant to the mixed dispersion and heating to form core particles;
To the mixed dispersion in which the core particles are formed, a second resin fine particle dispersion in which second resin fine particles made of the second binder resin and having a volume average particle size of 1 μm or less are dispersed is added. An attachment step of attaching the second resin fine particles to the surface of the core particles to form attached resin agglomerated particles;
The method for producing a toner for developing an electrostatic charge image according to any one of <1> to <3>, comprising a fusing step of fusing the adhered resin aggregated particles.

<5>
<1>-<3> The electrostatic charge image developing developer containing the electrostatic image developing toner as described in any one of.

<6>
An image bearing member; a charging unit that charges the surface of the image bearing member; an exposure unit that forms an electrostatic latent image according to image information on the charged surface of the image bearing member; And developing means for forming a toner image on the surface of the image carrier, transfer means for transferring the toner image from the surface of the image carrier to the surface of the recording medium, and transferring to the surface of the recording medium. An image forming apparatus including a fixing unit that heats and pressurizes the toner image thus formed to form an image;
An image forming apparatus, wherein the toner is the electrostatic charge image developing toner according to any one of <1> to <3>.

<7>
The fixing unit includes a heating unit having at least a function of heating the toner image;
<6> The image forming apparatus according to <6>, wherein the temperature of the heating unit is maintained at a temperature lower than that at the time of fixing when an image is not formed.

<8>
The image forming apparatus according to <6> or <7>, wherein an actual average fixing temperature of the fixing unit is 120 ° C. or lower.

<9>
<7> or <8>, wherein a set temperature at the time of fixing at the nip portion of the fixing unit is 120 ° C. or less and satisfies the following formula (3) and / or the following formula (4): This is an image forming apparatus.
Formula (3) T (on) −T (off) ≧ 10
Formula (4) Q ≦ 100
[In formula (3), T (on) is a set temperature (° C.) at the time of fixing at the nip portion of the fixing unit, T (off) is a set temperature (° C.) at the time of waiting for the nip portion of the fixing unit, In (4), Q represents the heat capacity (J / ° C.) of the heating member of the fixing means. ]

  As described above, according to the present invention, an electrostatic charge image that can be fixed at a low temperature and has almost no change in color tone between images formed on each sheet even when images are continuously formed. A developing toner, a production method thereof, and a developer for developing an electrostatic image using the toner for developing an electrostatic image can be provided.

<Toner for electrostatic image development>
The toner for developing an electrostatic charge image of the present invention (hereinafter sometimes abbreviated as “toner”) includes a core layer containing a first binder resin and a colorant, a second binder resin, and the core layer. In the toner for developing an electrostatic charge image having a shell layer for covering the above, the following formula (1) and the following formula (2) are satisfied.
Formula (1) 2.0 × 10 ⁵ ≦ G ′ (60) ≦ 4.0 × 10 ⁶
Formula (2) 10 ≦ G ′ (60) / G ′ (80) ≦ 40

  In the formulas (1) and (2), G ′ (60) is a toner storage measured under the conditions of a temperature of 60 ° C., a vibration frequency of 6.28 rad / sec, and a strain amount of 0.01 to 0.5%. G ′ (80) is a storage elastic modulus (Pa) of the toner measured under conditions of a temperature of 80 ° C., a vibration frequency of 6.28 rad / sec, and a strain amount of 0.01 to 0.5%. Represents.

Since the toner of the present invention has a storage elastic modulus G ′ (60) at 60 ° C. in the range of 2.0 × 10 ⁵ Pa to 4.0 × 10 ⁶ Pa as shown in Formula (1), Fixing is possible. When the storage elastic modulus G ′ (60) at 60 ° C. is less than 2.0 × 10 ⁵ Pa, the elasticity of the toner is small, so that the toner is liable to be deformed in the process of transferring the toner, resulting in transfer failure. On the other hand, when the storage elastic modulus G ′ (60) at 60 ° C. is larger than 4.0 × 10 ⁶ Pa, fixing at a low temperature becomes difficult due to the elasticity of the toner.
The storage elastic modulus G ′ (60) at 60 ° C. is preferably in the range of 5 × 10 ⁵ Pa to 3 × 10 ⁶ Pa, more preferably in the range of 8 × 10 ⁵ Pa to 2 × 10 ⁶ Pa. .

  Further, the toner of the present invention has a ratio G ′ (60) / 60 of the storage elastic modulus G ′ (60) at 60 ° C. and the storage elastic modulus G ′ (80) at 80 ° C. as shown in the formula (2). Since G ′ (80) is in the range of 10.0 or more and 40.0 or less, even when images are continuously formed, a change in color tone (coloring property) between images formed for each sheet occurs. The same effect can be maintained even when there is almost no fixing at a lower temperature. In addition to this, it is possible to maintain high color developability of the formed image.

Here, the ratio G ′ (60) / G ′ (80) of the storage elastic modulus G ′ (60) at 60 ° C. and the storage elastic modulus G ′ (80) at 80 ° C. is the temperature dependence of the viscoelasticity of the toner at low temperature. When G ′ (60) / G ′ (80) is large, the sharp melt property of the toner is strong, and when G ′ (60) / G ′ (80) is small, the sharp melt property is weak.
When G ′ (60) / G ′ (80) is larger than 40, the temperature dependence of the viscoelasticity of the toner is too large, and there is a variation in color developability for each sheet when images are continuously formed. It becomes noticeable and a stable image cannot be obtained. On the other hand, when G ′ (60) / G ′ (80) is smaller than 10, since the viscoelasticity of the toner at 80 ° C. is large, the toner is not sufficiently melted at a low temperature, and the color developability itself is lowered.
G ′ (60) / G ′ (80) is preferably 10 or more and 30 or less, and more preferably 15 or more and 25 or less.

  Further, the toner of the present invention has two peaks (maximum values) within a range of 30 ° C. or more and 90 ° C. or less of tangent loss measured at 6.28 rad / sec and a strain amount of 0.01 to 0.5%. It is preferable. This peak of tangent loss represents the movement of the main chain of the binder resin component contained in the toner. When two peaks exist, two types of binder resins are in an incompatible state in the toner. It shows that it exists independently.

In the toner of the present invention, since the first binder resin contained in the core layer and the second binder resin contained in the shell layer are used, there are two tangential loss peaks. This means that these two types of binder resins exist independently in the toner in an incompatible state.
Thus, in the state where there are two tangent loss peaks in the range of 30 ° C. or more and 90 ° C. or less, the temperature dependence (gradient) of the viscoelasticity of the toner is controlled so as to satisfy the condition shown in Expression (2). It is preferable in that it is easy to do.
When only one tangent loss peak exists within the range of 30 ° C. or more and 90 ° C. or less, the two types of binder resins are compatible in the toner, so that the gradient of the temperature dependence of the toner viscoelasticity is effectively obtained. Does not change so much, and the temperature dependence curve of viscoelasticity tends to shift. Therefore, it may be difficult to control the temperature dependence (inclination) of the viscoelasticity of the toner so as to satisfy the condition shown in Expression (2).

In the present invention, the storage elastic modulus and tangent loss (loss elastic modulus) were determined from dynamic viscoelasticity measured by a sinusoidal vibration method. For measurement of dynamic viscoelasticity, an ARES measuring apparatus manufactured by Rheometric Scientific was used.
For measurement of dynamic viscoelasticity, a toner was molded into a tablet and then set on an 8 mm diameter parallel plate. After normal force was set to 0, sinusoidal vibration was applied at a vibration frequency of 6.28 rad / sec. The measurement started from 20 ° C. and continued up to 100 ° C. at a heating rate of 1 ° C./min. In this case, the measurement time interval is 30 seconds.
Further, before the measurement, the stress dependence of the strain amount was confirmed at intervals of 10 ° C. from 20 ° C. to 100 ° C., and the range of the strain amount satisfying the linear relationship between the stress and the strain amount at each temperature was obtained. During measurement, the strain amount at each measurement temperature is maintained within the range of 0.01% to 0.5%, and the stress and strain amount are controlled to have a linear relationship at all temperatures, and these measurement results are used. The storage modulus and tangent loss were determined.

  Next, a method for producing the toner of the present invention, constituent materials, and the like will be described. As a method for producing the toner of the present invention, a toner having a so-called core-shell structure having a core layer containing a first binder resin and a colorant and a shell layer containing a second binder resin and covering the core layer. Any known method can be used as long as it is a method that can be used, but it is generally preferable to use a wet method, particularly an emulsion polymerization aggregation method.

In this case, the method for producing the toner of the present invention includes a first resin fine particle dispersion in which first resin fine particles having a volume average particle diameter of 1 μm or less are dispersed, and a colorant. The flocculant is added to the mixed dispersion obtained by mixing at least the dispersed colorant dispersion and heated to form the core particles, and the second dispersion is added to the mixed dispersion formed with the core particles. A second resin fine particle dispersion made of a resin and having a volume average particle diameter of 1 μm or less dispersed therein is added, and the second resin fine particles are adhered to the surface of the core particles. It is preferable to include an adhesion step for forming the resin agglomerated particles and a fusion step for fusing the adhering resin agglomerated particles.
In the aggregation step, core particles (core aggregated particles) simply formed by aggregating various fine particle components in the mixed dispersion liquid may be formed, and the heating temperature is higher than the glass transition temperature of the first binder resin. You may form the core particle (core fusion particle) which made it high and united simultaneously with aggregation. Further, the fusing step may be performed by heating to a temperature higher than the glass transition temperature of the first or second binder resin, which is higher than the glass transition temperature. If it is formed, it may be fused using mechanical stress. Details of these steps will be described later.

The toner of the present invention includes a first binder resin and a colorant in the core layer, and a second binder resin in the shell layer. Various additives may be internally added, or various external additives such as fluidization aids may be externally added.
In the following, the constituent material of the toner of the present invention will be described in more detail in consideration of the case where it is used in the above-described emulsion polymerization aggregation method. The materials listed below can be used.

-First binder resin (binder resin for core layer)-
As the first binder resin used in the present invention (hereinafter sometimes referred to as “core layer binder resin”), a known non-crystalline or crystalline resin can be used. In some cases, specifically, the following materials can be used.
That is, examples of the amorphous resin include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, and methacrylic acid. Esters having a vinyl group such as methyl, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; vinyl nitriles such as acrylonitrile and methacrylonitrile; vinyl methyl ether, vinyl isobutyl ether, etc. Vinyl ethers; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; polymers such as monomers such as polyolefins such as ethylene, propylene and butadiene; Or combinations copolymer, or mixtures thereof polymers and copolymers thereof.

  Furthermore, it was synthesized using the above-mentioned resins, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc., non-vinyl condensation resins, or these and the above vinyl monomers. Examples thereof include a mixture with a vinyl resin, and a graft polymer obtained by polymerizing a vinyl monomer in the presence of these. These resins may be used alone or in combination of two or more.

  Among these, when a vinyl monomer is used, a resin fine particle dispersion can be prepared by performing emulsion polymerization or seed polymerization using an ionic surfactant or the like. Dissolve the resin in a solvent with relatively low solubility in water, disperse the fine particles in water with a disperser such as a homogenizer in the presence of an ionic surfactant or polymer electrolyte in water, and then heat or reduce the pressure. A desired resin fine particle dispersion can be prepared by evaporating the solvent.

The thermoplastic binder resin can be stably produced as fine particles obtained by emulsion polymerization or the like by blending a dissociable vinyl monomer.
Examples of dissociative vinyl monomers include acrylic acid, methacrylic acid, maleic acid, cinnamic acid, fumaric acid, vinyl sulfonic acid, ethyleneimine, vinylpyridine, vinylamine and other polymer acids and polymer base materials. Any of the following monomers can be used, but a polymer acid is preferred from the standpoint of ease of polymer formation reaction. Furthermore, dissociative vinyl monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, cinnamic acid, and fumaric acid are particularly effective for controlling the polymerization degree and the glass transition point.

A crystalline resin can also be used as the binder resin for the core layer. Here, “crystallinity” means that in differential scanning calorimetry (DSC), it has a clear endothermic peak, not a stepwise endothermic amount change. Specifically, the temperature rising rate is 10 ° C./min. It means that the half-value width of the endothermic peak when measured at is within 6 ° C.
Among the crystalline resins, polyester resins are preferable from a practical viewpoint such as storage stability of an image after being made into a toner. Although the example of a polyester resin is demonstrated below, this invention is not limited to this.

The crystalline polyester resin and all other polyester resins used in the present invention are synthesized from a polyvalent carboxylic acid component and a polyhydric alcohol component. In the present invention, a commercially available product may be used as the polyester resin, or an appropriately synthesized product may be used.
Examples of the polyvalent carboxylic acid component include oxalic acid, succinic acid, glutaric acid, adipic acid, peric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12 -Aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconic acid Aromatic dicarboxylic acids such as dibasic acids, and the like, and anhydrides and lower alkyl esters thereof.

Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, anhydrides thereof, and lower ones thereof. Examples thereof include alkyl esters. These may be used individually by 1 type and may use 2 or more types together.
Moreover, as an acid component, it is preferable that the dicarboxylic acid component which has a sulfonic acid group other than the above-mentioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid is contained. The dicarboxylic acid having a sulfonic acid group is effective in that it can favorably disperse a coloring material such as a pigment. Further, when the dicarboxylic acid has a sulfonic acid group, when the resin is emulsified or suspended in water to produce fine resin particles, as described later, it is emulsified or suspended without using a surfactant. It is also possible.

Examples of the dicarboxylic acid having a sulfonic acid group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. The divalent or higher carboxylic acid component having a sulfonic acid group is preferably contained in an amount of 1 to 15 mol%, more preferably 2 to 10 mol%, based on all carboxylic acid components constituting the polyester.
When the content is low, the stability of the emulsified particles with time deteriorates. On the other hand, when the content exceeds 15 mol%, not only the crystallinity of the polyester resin is deteriorated but also the process of coalescing the particles after aggregation is adversely affected. There is a problem that it becomes difficult to adjust.

  Furthermore, it is more preferable to contain a dicarboxylic acid component having a double bond in addition to the aforementioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid. A dicarboxylic acid having a double bond can be suitably used to prevent hot offset at the time of fixing in that it can be radically cross-linked through the double bond. Examples of such dicarboxylic acids include, but are not limited to, maleic acid, fumaric acid, 3-hexenedioic acid, and 3-octenedioic acid. In addition, these lower esters, acid anhydrides and the like are also included. Among these, fumaric acid, maleic acid and the like are mentioned in terms of cost.

  As the polyhydric alcohol component, an aliphatic diol is preferable, and a linear aliphatic diol having 7 to 20 carbon atoms in the main chain portion is more preferable. When the aliphatic diol is branched, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability may be deteriorated. Further, when the number of carbon atoms is less than 7, when the polycondensation with aromatic dicarboxylic acid is performed, the melting point becomes high and fixing at low temperature may be difficult. On the other hand, when the number exceeds 20, it is difficult to obtain practical materials. easy. The carbon number is more preferably 14 or less.

  Specific examples of the aliphatic diol preferably used for the synthesis of the crystalline polyester used in the present invention include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentane. Diol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol, and the like, but are not limited thereto. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable in view of availability.

Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. These may be used individually by 1 type and may use 2 or more types together.
Among the polyhydric alcohol components, the content of the aliphatic diol component is preferably 80 mol% or more, and more preferably 90 mol% or more. If the content of the aliphatic diol component is less than 80 mol%, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability may be deteriorated. is there. If necessary, monovalent acids such as acetic acid and benzoic acid, and monovalent alcohols such as cyclohexanol and benzyl alcohol can also be used for the purpose of adjusting the acid value and hydroxyl value.

  These crystalline resins are dispersed in an aqueous medium such as water together with a polymer electrolyte such as an ionic surfactant, polymer acid, and polymer base, heated above the melting point, and capable of applying a strong shearing force. Alternatively, a resin fine particle dispersion can be obtained by processing using a pressure discharge type dispersing machine.

In addition, the core layer binder resin used in the present invention may be a mixture of a plurality of types of resins. Furthermore, it is also possible to mix a crystalline resin and an amorphous resin.
The volume average particle size of the resin fine particles used for producing the toner is desirably 1 μm or less, and more desirably in the range of 0.01 to 1 μm. When the volume average particle diameter of the resin fine particles exceeds 1 μm, the particle size distribution and shape distribution of the finally obtained electrostatic latent image developing toner are broadened, or generation of free particles occurs, causing uneven distribution of the toner, In some cases, performance and reliability may be reduced.
On the other hand, if the volume average particle size of the resin fine particles is within the above range, the above disadvantages are not obtained, the uneven distribution between the toners is reduced, the dispersion in the toners is improved, and the variation in performance and reliability is reduced. Is advantageous. The volume average particle diameter of the resin fine particles can be measured using, for example, a microtrack.

-Second binder resin (binder resin for shell layer)-
The second binder resin used in the present invention (hereinafter sometimes referred to as “shell layer binder resin”) can be made of the same material as the core layer binder resin. It is not very preferable to use. When a crystalline resin is used as the material for the shell layer, which is the outermost layer of the toner, the crystalline resin is highly dependent on the environment of electrical resistance, so the chargeability of the toner is significantly reduced in a high humidity environment. Because there is a case to do.
As the shell layer binder resin, it is preferable to select a material that easily exists in an incompatible state with the core layer binder resin in the toner when the toner is produced. It is preferable to select production conditions that are likely to be in a molten state.

The binder resin for the core layer and the binder resin for the shell layer used for the preparation of the toner are different from the solubility parameter (SPc) of the binder resin for the core layer and the solubility parameter (SPs) of the binder resin for the shell layer. (ΔSP = | SPc−SPs |) is preferably selected to be in a range of 0.2 to 0.6, and more preferably selected to be in a range of 0.2 to 0.4.
If the ΔSP value is less than 0.2, the binder resin for the core layer and the binder resin for the shell layer are compatible in the toner, making it difficult to control the viscoelasticity so as to satisfy the condition shown in the formula (2). It may become. If the ΔSP value is larger than 0.6, the affinity between the binder resin for the core layer and the binder resin for the shell layer is poor, and it becomes difficult to uniformly fuse these two types of resins, so that the toner can be formed. It may disappear.

Further, the ratio of the storage elastic modulus G ′ _core (80) of the core layer binder resin at 80 ° C. to the shell layer binder resin G ′ _shell (80) at 80 ° C. (G ′ _shell (80) / G ′ _core (80)) is preferably used in combination with the binder resin for the core layer and the binder resin for the shell layer so that the ratio is 5 to 50, and this ratio is more preferably 10 to 30.

When G ′ _shell (80) / G ′ _core (80) is smaller than 5, it is difficult to obtain the temperature dependency (gradient) of the toner viscoelasticity that satisfies the condition shown in Expression (2). There is.
In addition, when G ′ _shell (80) / G ′ _core (80) is larger than 50, the storage elastic modulus difference between the core layer binder resin and the shell layer binder resin is too large. At a single fixing temperature set in the fixing machine, the binder resin for the core layer may be melted and the binder resin for the shell layer may be unmelted. In this case, as a result, the fused area and the unmelted area are mixed on the fixed image, and thus the uniformity of the image surface may be lost and the color developability may be deteriorated.
Further, in order to easily realize the viscoelasticity control of the toner satisfying the condition shown in the formula (2), the storage elastic modulus G ′ _core (80) at 80 ° C. of the binder resin for the core layer is 1 ×. The range of 10 ⁴ Pa to 1 × 10 ⁵ Pa is preferable, and the storage elastic modulus G ′ _shell (80) at 80 ° C. of the binder resin for the shell layer is 5 × 10 ⁴ Pa to 5 × 10 ^6. Within the range of Pa is preferable.

  In the present invention, the SP value (solubility parameter) means a value determined by the Fedors method. The SP value in this case is defined by the following formula (3).

In Formula (3), SP represents a solubility parameter, ΔE represents a cohesive energy (cal / mol), V represents a molar volume (cm ³ / mol), and Δei represents the i-th atom or atomic group. Evaporation energy (cal / atom or atomic group), Δvi represents the molar volume (cm ³ / atom or atomic group) of the i-th atom or atomic group, and i represents an integer of 1 or more.

Note that the SP value represented by the formula (3) is conventionally obtained so that its unit is cal ^1/2 / cm ^3/2 and is expressed in a dimensionless manner. In addition, in the present invention, since the relative difference in SP value between two compounds is significant, in the present invention, the values obtained in accordance with the above-described practice are used and expressed in a dimensionless manner. It was.
For reference, when the SP value represented by the formula (3) is converted into SI units (J ^1/2 / m ^3/2 ), it may be multiplied by 2046.

-Colorant particles-
The colorant used in the toner is not particularly limited, and known pigments and dyes can be used. Examples of the pigment include black pigment, yellow pigment, orange pigment, red pigment, blue pigment, purple pigment, green pigment, white pigment, extender pigment and the like.
Examples of the black pigment include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon and the like.
Examples of the yellow pigment include yellow lead, zinc yellow, yellow iron oxide, cadmium yellow, chrome yellow, Hansa yellow, Hansa yellow 10G, benzidine yellow G, benzidine yellow GR, selenium yellow, quinoline yellow, and permanent yellow NCG. Etc.

Examples of the orange pigment include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, benzidine orange G, indanthrene brilliant orange RK, indanthrene brilliant orange GK and the like.
Examples of the red pigment include bengara, cadmium red, red lead, mercury sulfide, watch young red, permanent red 4R, risor red, brilliant carmine 3B, brilliant carmine 6B, dupont oil red, pyrazolone red, rhodamine B lake and lake. Examples include Red C, Rose Bengal, Eoxin Red, Alizarin Lake and the like.

Examples of the blue pigment include, for example, bitumen, cobalt blue, alkali blue lake, Victoria blue lake, fast sky blue, indanthrene blue BC, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, Examples include malachite green oxalate.
Examples of the purple pigment include manganese purple, fast violet B, and methyl violet lake.

Examples of the green pigment include chromium oxide, chromium green, pigment green, phthalocyanine green, malachite green lake, final yellow green G, and the like.
Examples of the white pigment include zinc white, titanium oxide, antimony white, and zinc sulfide. Examples of the extender pigment include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white.

  Examples of the dye include various dyes such as basic, acidic, dispersion, and direct dyes, such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, dioxazine, thiazine, azomethine, Various dyes such as indico, thioindico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, thiazine, thiazole, xanthene, more specifically nigrosine, methylene blue, rose bengal, Examples include quinoline yellow and ultramarine blue.

These colorants may be used alone or in combination of two or more, and may further be used in a solid solution state. When two or more types are used in combination, the color of the toner can be arbitrarily adjusted by changing the type and mixing ratio of the colorant.
The colorant is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP permeability, and dispersibility in the toner. The addition amount of the colorant contained in the toner is preferably 1 to 20% by mass, more preferably 4 to 15% by mass.
In preparing the colorant dispersion, these colorants are dispersed in an aqueous medium by a known method. For the dispersion, for example, a media type dispersing machine such as a rotary shearing homogenizer, a ball mill, a sand mill, or an attritor, a high pressure opposed collision type dispersing machine, or the like is preferably used.

-Release agent particles-
Known release agents can be used as the release agent used in the present invention. For example, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point by heating; oleic acid amide and erucic acid amide , Fatty acid amides such as ricinoleic acid amide and stearic acid amide; plant wax such as ester wax, carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, etc .; animal wax such as beeswax; Minerals such as wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax and the like, petroleum-based waxes, and modified products thereof can be used.
The release agent dispersion liquid disperses the above-mentioned release agent together with a polymer electrolyte such as an ionic surfactant, polymer acid or polymer base in water, and heats above the melting point and gives strong shear. It can be obtained by making fine particles with a homogenizer or pressure discharge type disperser. In this case, it is easy to set the particle size of the release agent particles dispersed in the release agent dispersion to 1 μm or less suitable for toner preparation.

The volume average particle size of the release agent particles is desirably 1 μm or less, and more desirably in the range of 0.01 to 1 μm. If the volume average particle size exceeds 1 μm, the particle size distribution and shape distribution of the final toner will be broadened, or free particles will be generated, resulting in uneven composition of the toner, leading to deterioration in performance and reliability. There is.
On the other hand, when the volume average particle size of the release agent particles is within the above range, the above disadvantages are eliminated, uneven distribution among the toners is reduced, dispersion in the toners is improved, and variations in performance and reliability are small. This is advantageous. The volume average particle diameter can be measured using, for example, a microtrack.

-Other ingredients-
Examples of other components that are internally or externally added to the toner include a charge control agent, inorganic particles, organic particles, lubricant, abrasive, and magnetic powder.
Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments. In addition, as the charge control agent in the present invention, a material that is difficult to dissolve in water is preferable in terms of controlling ionic strength that affects stability during aggregation and fusion and reducing wastewater contamination.

Examples of the inorganic particles include all particles usually used as an external additive on the toner surface, such as silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate, and cerium oxide.
Examples of the organic particles include all particles usually used as external additives on the toner surface, such as vinyl resins, polyester resins, and silicone resins. These inorganic particles and organic particles can be used as fluidity aids, cleaning aids, and the like.

Examples of the lubricant include fatty acid amides such as ethylene bisstearylamide and oleic acid amide, and fatty acid metal salts such as zinc stearate and calcium stearate. Examples of the abrasive include the aforementioned silica, alumina, cerium oxide, and the like.
Examples of the magnetic powder include substances that are magnetized in a magnetic field, such as metals such as iron, cobalt, nickel, and manganese, ferromagnetic powders such as alloys or compounds containing these, and compounds such as ferrite and magnetite. Can be mentioned. When the magnetic powder is used, it is necessary to pay attention to the water layer transferability of the magnetic material, and it is preferable to subject the magnetic material to surface modification such as a hydrophobic treatment.

  When these other components are used in the preparation of toner in the form of particles, the volume average particle diameter is preferably 0.01 to 1 μm. The volume average particle diameter can be measured using, for example, a microtrack.

-Dispersion-
Next, the dispersion medium used in preparing various dispersions used in the production of the toner of the present invention, secondary components such as a surfactant, the adjusting method, and the like will be described.
First, examples of the dispersion medium 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.

In the present invention, it is preferable to add and mix a surfactant in the aqueous medium when preparing the dispersion.
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 Preferable examples include nonionic surfactants such as glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, an ionic surfactant is preferable, and an anionic surfactant and a cationic surfactant are more preferable.
The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. The said surfactant may be used individually by 1 type, and may use 2 or more types together.

  Specific examples of the anionic surfactant include fatty acid soaps such as potassium laurate, sodium oleate and sodium castor oil; sulfates such as octyl sulfate, lauryl sulfate, lauryl ether sulfate and nonylphenyl ether sulfate; lauryl sulfonate , Dodecyl sulfonate, dodecyl benzene sulfonate, triisopropyl naphthalene sulfonate, dibutyl naphthalene sulfonate, etc. Sulfonates such as lauryl phosphate, isopropyl phosphate Phosphoric acid esters such as nonyl phenyl ether phosphate; dialkyl sodium sulfosuccinates, such as sodium dioctyl sulfosuccinate, sodium lauryl sulfosuccinate 2, polyoxyethylene sulfo sulfosuccinate salts such as succinic acid lauryl disodium; and the like.

  Specific examples of the cationic surfactant include laurylamine hydrochloride, stearylamine hydrochloride, oleylamine acetate, stearylamine acetate, stearylaminopropylamine acetate, and other amine salts; lauryltrimethylammonium chloride, dilauryldimethylammonium Chloride, distearyl ammonium chloride, distearyl dimethyl ammonium chloride, lauryl dihydroxyethyl methyl ammonium chloride, oleyl bispolyoxyethylene methyl ammonium chloride, lauroylaminopropyldimethylethylammonium ethosulphate, lauroylaminopropyldimethylhydroxyethylammonium perchlorate, alkylbenzene dimethyl Ammonium chloride, alkylto Quaternary ammonium salts such as ammonium chloride; and the like.

  Specific examples of the nonionic surfactant include polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether and other alkyl ethers; Alkylphenyl ethers such as oxyethylene nonylphenyl ether; alkyl esters such as polyoxyethylene laurate, polyoxyethylene stearate, polyoxyethylene oleate; polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, polyoxy Alkylamines such as ethylene oleyl amino ether, polyoxyethylene soybean amino ether, polyoxyethylene beef tallow amino ether; Alkyl amides such as xylethylene lauric acid amide, polyoxyethylene stearic acid amide, polyoxyethylene oleic acid amide; vegetable oil ethers such as polyoxyethylene castor oil ether, polyoxyethylene rapeseed oil ether; lauric acid diethanolamide, stearin Alkanolamides such as acid diethanolamide and oleic acid diethanolamide; sorbitan ester ethers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate And the like.

In the aggregation process, as described above, the first resin fine particle dispersion and the mixed dispersion at least mixed with the colorant dispersion are used. In the case of producing a toner capable of so-called oilless fixing. In addition, it is preferable to mix a release agent dispersion.
In the mixed dispersion obtained by mixing these three kinds of dispersions, the content of the first resin fine particles with respect to the total solid content is preferably 40% by mass or less, and is within a range of about 2 to 20% by mass. Is more preferable. Moreover, as content of a coloring agent, it is preferable that it is 50 mass% or less, and it is more preferable that it exists in the range of about 2-40 mass%. Furthermore, as content of a mold release agent, it is preferable that it is 50 mass% or less, and it is more preferable that it exists in the range of about 5-40 mass%.
Furthermore, when other internal components (particles) are further added to the mixed dispersion obtained by mixing the three types of dispersions, the content of the other internal components should generally be very small. It is enough. Specifically, the content of the other internal components is preferably about 0.01 to 5% by mass, and in the range of about 0.5 to 2% by mass with respect to the total solid content contained in the mixed dispersion. More preferably, it is within.

  In addition, there is no restriction | limiting in particular about the preparation methods of various dispersion liquids, The method suitably selected according to the objective can be employ | adopted. There are no particular restrictions on the means of dispersion, but usable devices include, for example, Homomixer (Special Machine Industries Co., Ltd.), Thrasher (Mitsui Mine Co., Ltd.), Cavitron (Eurotech Co., Ltd.), Examples of the dispersing device known per se include Dizer (Mizuho Kogyo Co., Ltd.), Menton Gorin homogenizer (Gorin Co., Ltd.), Nanomizer (Nanomizer Co., Ltd.), Static Mixer (Noritake Co.).

-Toner production method-
Next, the toner production method of the present invention including the above-described aggregation process, adhesion process, and fusion process will be described in detail for each process.

-Aggregation process-
In the aggregating step, first, the first binder resin dispersion, the colorant dispersion, further the release agent dispersion used as necessary, and the mixed dispersion obtained by mixing other components are used. By adding an aggregating agent and heating at a temperature slightly lower than the melting point of the first binder resin, aggregated particles (core aggregated particles) are formed by aggregating particles composed of the respective components. It is also possible to form a fused particle (core fused particle) by heating at a temperature equal to or higher than the glass transition temperature of the first binder resin and performing fusion simultaneously with aggregation.
Aggregated particles are formed by adding an aggregating agent at room temperature while stirring with a rotary shearing homogenizer. As the aggregating agent used in the aggregating step, a surfactant having a reverse polarity to the surfactant used as a dispersing agent for various dispersions, an inorganic metal salt, and a divalent or higher metal complex can be suitably used.
In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Of these, aluminum salts and polymers thereof are particularly preferred. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more suitable.

-Adhesion process-
In the attaching step, resin fine particles made of the second binder resin are attached to the surface of the core particles (core aggregated particles or core fusion particles) containing the first binder resin formed through the above-described aggregation step. Thus, the coating layer is formed (hereinafter, the agglomerated particles provided with the coating layer on the core particle surfaces are referred to as “adhesive resin agglomerated particles”). Here, this coating layer corresponds to the shell layer of the toner of the present invention formed through a fusion process described later.
The coating layer can be formed by additionally adding the second resin fine particle dispersion to the dispersion in which the core particles are formed in the aggregation step, and additionally adding other components simultaneously as necessary. Also good.
When the adhesion resin aggregated particles are uniformly adhered to the surface of the core particles to form a coating layer, and the adhesion resin aggregated particles are heat-fused in a fusion step described later, The resin fine particles made of the binder resin 2 are melted to form a shell layer. For this reason, it is possible to effectively prevent the components such as the release agent contained in the core layer located inside the shell layer from being exposed to the surface of the toner.

  There is no restriction | limiting in particular as a method of addition mixing of the 2nd resin fine particle dispersion in an adhesion | attachment process, For example, you may carry out gradually continuously and may carry out in steps divided into several times. Thus, by adding and mixing the second resin fine particle dispersion, the generation of fine particles can be suppressed, and the particle size distribution of the toner obtained can be sharpened.

In the present invention, the number of times this adhesion step is performed may be one or a plurality of times. In the former case, only one layer mainly composed of the second binder resin is formed on the surface of the core aggregated particles. On the other hand, in the latter case, if not only the second resin fine particle dispersion but also a plurality of fine particle dispersions composed of a release agent dispersion and other components are used, a specific component is mainly contained on the surface of the core aggregated particles. A layer as a component is laminated.
The latter case is advantageous in that a toner having a complicated and precise hierarchical structure can be obtained, and a desired function can be imparted to the toner. When the adhesion process is performed a plurality of times or in multiple stages, the composition and physical properties of the obtained toner from the surface to the inside can be changed in stages, and the structure of the toner can be easily controlled. In this case, a plurality of layers are laminated stepwise on the surface of the core particles, and a structural change or composition gradient can be given from the inside to the outside of the toner particles, and the physical properties can be changed. In this case, the shell layer corresponds to all the layers laminated on the surface of the core particle, and the outermost layer is composed of a layer mainly composed of the second binder resin. In the following explanation, explanation will be made on the assumption that the adhesion process is performed only once.

Conditions for attaching the resin fine particles made of the second binder resin to the core particles are as follows. That is, the heating temperature in the adhering step is preferably a temperature in the vicinity of the melting point of the first binder resin contained in the core aggregated particles, and specifically, a temperature range within the melting point ± 10 ° C. preferable.
When heated at a temperature lower than the melting point of the first binder resin by more than 10 ° C., the resin fine particles composed of the first binder resin existing on the surface of the core particles and the second binder attached to the surface of the core aggregated particles Resin fine particles made of resin are less likely to adhere, and as a result, the thickness of the formed shell layer may be uneven.

Further, when heated at a temperature higher than the melting point of the first binder resin by more than 10 ° C., the resin fine particles composed of the first binder resin present on the core particle surface and the second binder adhered to the core particle surface. Resin fine particles made of a resin are easily attached.
However, since the adhesion is too high, adhesion between the adhered resin aggregated particles also occurs, and the particle size / particle size distribution of the obtained toner is destroyed. The heating time in the adhesion step depends on the heating temperature and cannot be defined generally, but is usually about 5 minutes to 2 hours.
In the attaching step, the dispersion obtained by additionally adding the second resin fine particle dispersion to the mixed dispersion in which the core particles are formed may be allowed to stand or be gently stirred by a mixer or the like. Also good. The latter case is advantageous in that uniform adhered resin aggregated particles are easily formed.

-Fusion process-
In the fusion process, the adhered resin aggregated particles obtained in the adhesion process are fused by heating. The fusing step can be performed at a temperature equal to or higher than the glass transition temperature of the first binder resin and the second binder resin. As the fusion time, a short time is sufficient if the heating temperature is high, and a long time is necessary if the heating temperature is low. That is, the fusion time depends on the temperature of heating and cannot be defined in general, but is generally 30 minutes to 10 hours.

  In the fusion step, the two types of binder resins may be heated to the melting point or higher and the crosslinking reaction may be performed simultaneously, or after the fusion is completed, the crosslinking reaction may be performed. In carrying out the crosslinking reaction, for example, an unsaturated sulfonated crystalline polyester resin obtained by copolymerizing a double bond component as the binder resin can be used. In the cross-linking reaction, a cross-linked structure is introduced by causing a radical reaction or the like to occur in the binder resin having such cross-linking reactivity. At this time, the following polymerization initiator is used.

  Examples of the polymerization initiator include t-butyl peroxy-2-ethylhexanoate, cumyl perpivalate, t-butyl peroxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t. -Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxycarboni) L) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, , 3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylper) Oxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxy) Cyclohexyl) propane, di-t-butylperoxy α-methylsuccinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexahydroterephthalate Di-t-butylperoxyazelate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate), di-t-butylper Oxytrimethyl adipate, tris (t-butylperoxy) triazine, vinyltris (t-butylperoxy) silane, 2,2'-azobis (2-methylpropionamidine dihydrochloride), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine], 4,4′-azobis (4-cyanovaleric acid) and the like. These polymerization initiators can be used alone or in combination of two or more. The amount and type of the polymerization initiator are selected depending on the amount of unsaturated sites in the binder resin and the type and amount of the coexisting colorant.

  The polymerization initiator may be mixed with the binder resin component in advance before the emulsification step for adjusting the resin fine particle dispersion or the like, or may be incorporated into the core particles formed in the aggregation step. Further, it may be introduced after the fusion step or after the fusion step. In the case of introduction after the aggregation step, the adhesion step, the fusion step, or the fusion step, a solution in which the polymerization initiator is dissolved or emulsified is added to a dispersion (resin fine particle dispersion, etc.) used in each step. These polymerization initiators may be added with known crosslinking agents, chain transfer agents, polymerization inhibitors and the like for the purpose of controlling the degree of polymerization.

  When the core particles are core fusion particles, resin fine particles made of the second binder resin may be attached. In this case, the dispersion containing the core fusion particles is once filtered, and the water content of the dispersion is controlled to 30% by mass to 50% by mass, and then the second resin fine particle dispersion is further added. Thereby, the fine particles made of the second binder resin are adhered to the surface of the core fusion particle.

When the water content of the dispersion is lower than 30% by mass, the adhesion of fine particles made of the second binder resin is poor, and the fine particles may be released from the core fusion particles. On the other hand, if the moisture content is higher than 50% by mass, stirring may be difficult, and the fine particles composed of the second binder resin may not adhere uniformly to the surface of the core fusion particles.
In addition, mechanical stress by a Henschel mixer or the like is applied to the adhered resin agglomerated particles obtained by adhering the fine particles of the second binder resin to the surface of the core fused particles after the cleaning / drying process described later. Thus, the fine particles made of the second binder resin attached to the surface of the core fusion particles can be fused. Thus, the fusion process can be performed by applying mechanical stress instead of heating in the liquid phase.

-Washing / drying process-
The fused particles obtained through the fusion process are subjected to solid-liquid separation such as filtration, washing, and drying. As a result, a toner in which no external additive is added is obtained.
The solid-liquid separation is not particularly limited, but suction filtration, pressure filtration and the like are preferable from the viewpoint of productivity. The washing is preferably performed with substitution washing with ion-exchanged water from the viewpoint of chargeability. In the drying process, an arbitrary method such as a normal vibration type fluidized drying method, a spray drying method, a freeze drying method, or a flash jet method can be adopted. The toner particles should have a moisture content after drying of preferably 1.0% by mass or less, more preferably 0.5% by mass or less.

The toner particles granulated through the drying step as described above can be used by appropriately selecting known additives and the like as other components according to the purpose. Specific examples include various known additives such as inorganic fine particles, organic fine particles, charge control agents, and release agents.
Examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride, Examples include Bengala, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, and silicon nitride. Among these, silica fine particles are preferable, and silica fine particles that have been hydrophobized are particularly preferable.

The inorganic fine particles are generally used for the purpose of improving fluidity. Among the inorganic fine particles, TiO (OH) ₂ metatitanate does not affect transparency, and has good chargeability, environmental stability, fluidity, caking resistance, stable negative chargeability, and stable image quality maintenance. It is possible to provide an excellent developer.
The hydrophobized compound of metatitanic acid preferably has an electric resistance of 10 ¹⁰ Ω · cm or more. This is because when a toner externally treated with a hydrophobized compound of metatitanic acid is used, even if the transfer electric field is increased, high transferability can be obtained without generating a toner having a reverse polarity. It is.

Examples of the organic fine particles include polystyrene, polymethyl methacrylate, and polyvinylidene fluoride. The organic fine particles are generally used for the purpose of improving cleaning properties and transferability.
The inorganic fine particles / organic fine particles preferably have a number average particle size of 80 nm or less, and more preferably 50 nm or less. When monodispersed spherical silica or monodispersed spherical organic resin fine particles are used as external additives, the median diameter of these external additives is 0.1 μm or more and less than 0.3 μm from the viewpoint of improving / maintaining transfer efficiency. It is preferable.
Examples of the charge control agent include salicylic acid metal salts, metal-containing azo compounds, nigrosine and quaternary ammonium salts. The charge control agent is generally used for the purpose of improving chargeability.

  In the present invention, the external additive is added to toner particles and mixed. The mixing can be performed by a known mixer such as a V-type blender, a Henschel mixer, and a Redige mixer. At this time, various additives may be added as necessary. Examples of the additive include other fluidizing agents, cleaning aids such as polystyrene fine particles, polymethyl methacrylate fine particles, and polyvinylidene fluoride fine particles, or transfer aids.

In the present invention, the adhesion state of the inorganic compound to the toner particle surface may be merely mechanical adhesion or may be loosely fixed to the surface. Further, the entire surface of the toner particles may be coated or a part thereof may be coated. The addition amount of the external additive is preferably in the range of 0.3 to 3 parts by mass, more preferably in the range of 0.5 to 2 parts by mass with respect to 100 parts by mass of the toner particles.
When the addition amount is less than 0.3 parts by mass, the toner may not be sufficiently fluidized, and blocking suppression due to storage in a high temperature environment tends to be insufficient. On the other hand, when the addition amount is more than 3 parts by mass, the coating is excessively covered. For this reason, the excessive inorganic oxide externally added to the surface of the toner particles may move to a member that comes into contact with the toner and cause a secondary failure. Moreover, it does not matter even if it goes through a sieving process after mixing an external additive.
The toner of the present invention can be suitably produced by the production methods as described above, but is not limited to these production methods.

<Developer for developing electrostatic image>
The developer for developing an electrostatic image of the present invention (hereinafter sometimes abbreviated as “developer”) is a one-component developer composed only of the toner of the present invention or a two-component composed of the toner of the present invention and a carrier. It can be used as a developer.
There is no restriction | limiting in particular as a carrier which can be used for a two-component developer, A well-known carrier can be used. As the carrier, a resin-coated carrier having a resin coating layer in which a conductive material is dispersed in a matrix resin can be used on the surface of the core material. The resin-coated carrier can maintain high image quality over a long period of time because the volume resistivity does not change greatly even if the resin coating layer peels off.

  Examples of the matrix resin include polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene- Acrylic acid copolymer, straight silicone resin composed of organosiloxane bond or its modified products, fluorine resin, polyester, polyurethane, polycarbonate, phenol resin, amino resin, melamine resin, benzoguanamine resin, urea resin, amide resin, epoxy resin, etc. Although it can illustrate, it is not limited to these.

Examples of the conductive material include metals such as gold, silver, and copper, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black, but are not limited thereto. It is not done. The content of the conductive material is preferably in the range of 1 to 50 parts by mass and more preferably in the range of 3 to 20 parts by mass with respect to 100 parts by mass of the matrix resin.
Examples of the carrier core material include those in which magnetic powder is used alone as the core material, or those in which magnetic powder is finely divided and dispersed in a resin. The magnetic powder is made into fine particles and dispersed in the resin. The resin and magnetic powder are kneaded and pulverized, the resin and magnetic powder are melted and spray dried, and the polymerization method is used to contain the magnetic powder in the solution. Examples thereof include a method of polymerizing a resin. From the viewpoint of controlling the true specific gravity and shape of the carrier, it is preferable to use a magnetic powder-dispersed core material produced by a polymerization method because of its high degree of freedom.

  The carrier preferably contains fine magnetic powder in an amount of 80% by mass or more with respect to the total weight of the carrier from the viewpoint of preventing carrier scattering. Examples of the magnetic material (magnetic powder) include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite. The volume average particle diameter of the core material is generally in the range of 10 to 500 μm, preferably in the range of 25 to 80 μm.

  As a method of forming the resin coating layer on the surface of the carrier core material, an immersion method in which the carrier core material is immersed in a coating layer forming solution containing the matrix resin, a conductive material and a solvent, a coating layer forming solution Spray method on the surface of the carrier core material, fluidized bed method in which the carrier core material is floated by flowing air and spraying the coating layer forming solution, mixing the carrier core material and the coating layer forming solution in a kneader coater And a kneader coater method for removing the solvent.

  The solvent used in the coating layer forming solution is not particularly limited as long as it dissolves the matrix resin. For example, aromatic hydrocarbons such as toluene and xylene, and ketones such as acetone and methyl ethyl ketone. And ethers such as tetrahydrofuran and dioxane can be used. The average film thickness of the resin coating layer is usually in the range of 0.1 to 10 μm, but in the present invention, in order to develop a stable volume resistivity of the carrier over time, in the range of 0.5 to 3 μm. It is preferable that

The volume specific resistance value of the carrier used in the present invention is in the range of 10 ⁶ to 10 ¹⁴ Ω · cm at 1000 V corresponding to the upper and lower limits of a normal development contrast potential in order to achieve high image quality. Preferably, it is in a range of 10 ⁸ to 10 ¹³ Ω · cm. When the volume resistivity value of the carrier is less than 10 ⁶ Ω · cm, the reproducibility of the thin line is poor, and the toner fog may easily occur on the background due to charge injection. On the other hand, if the volume specific resistance of the carrier is larger than 10 ¹⁴ Ω · cm, reproduction of black solid and halftone may be deteriorated. Further, the amount of carrier transferred to the image carrier (photoconductor) increases, and the photoconductor is easily damaged.
As the developer of the present invention, the toner of the present invention is preferably mixed and adjusted in the range of 3 to 15 parts by mass with respect to 100 parts by mass of the carrier.

<Image forming apparatus>
Next, the image forming apparatus of the present invention will be described. The image forming apparatus of the present invention is not particularly limited as long as it is an electrophotographic image forming apparatus using the toner of the present invention. Specifically, the image forming apparatus preferably has the following configuration.
That is, the image forming apparatus of the present invention includes an image carrier, a charging unit for charging the surface of the image carrier, and exposure for forming an electrostatic latent image corresponding to image information on the charged surface of the image carrier. Developing means for developing the electrostatic latent image with a developer containing toner to form a toner image on the surface of the image carrier; and transferring the toner image from the surface of the image carrier to the surface of the recording medium. The image forming apparatus preferably includes a transfer unit and a fixing unit that fixes the toner image transferred onto the surface of the recording medium by heating and pressing to form an image. The toner used in this case is the toner of the present invention.

Further, since the toner of the present invention has the effects as described above, the image forming apparatus of the present invention has (1) an image forming apparatus having a standby power saving function, and (2) a small heat capacity of the fixing device. Image forming apparatus (generally, a small image forming apparatus having a volume of 0.8 m ³ or less), (3) an image forming apparatus having a low fixing temperature, or any two or more of (1) to (3) It is preferable to combine the above features.

  The fixing unit (fixing machine) includes a heating unit such as a halogen lamp having at least a function of heating the toner image. Here, the standby power saving function means fixing when the temperature in the nip portion for fixing the heating means or the toner image (or the power consumption of the heating means) continues to be an image-free state (so-called standby state). The function of maintaining the temperature lower than the time (or the power consumption of the heating means).

When the image forming apparatus of the present invention is an image forming apparatus having a standby power saving function, the set temperature for controlling the fixing temperature in the nip portion is set between the standby time and the image forming time (fixing time). There is preferably a difference of 10 ° C. or more, more preferably a difference of 20 ° C. or more, and further preferably a difference of 25 ° C. or more. However, the difference in the set temperature between standby and image formation (fixing) is preferably 30 ° C. or less from a practical point of view, for example, to prevent the warm-up time from becoming longer than necessary.
In order to enable low-temperature fixing, the set temperature at the time of fixing at the nip portion of the fixing unit is preferably 120 ° C. or lower, more preferably 110 ° C. or lower, and preferably 100 ° C. or lower. Further preferred. Note that, when the set temperature at the time of fixing the nip portion is too low, it becomes difficult to melt the toner.
Furthermore, from the viewpoint of energy saving, downsizing of the apparatus, and shortening of the time required for warming up, the heat capacity of the heating member of the fixing means is preferably 100 J / ° C. or less, and more preferably 80 J / ° C. or less. . However, when the heat capacity Q of the heating member is too small, the overshoot becomes too large, so that it is practically preferably 30 J / ° C. or higher.

  In an apparatus in which the difference in set temperature between standby and image formation is larger, the energy saving effect increases, but the initial overshoot also increases. For this reason, even when images are continuously formed, variation in color tone (coloring property) between images formed on each sheet tends to increase. However, even in an apparatus having a large difference in set temperature between standby and image formation as described above, if the toner of the present invention is used, variation in color tone (color development) between images formed on each sheet can be easily suppressed. be able to.

  Note that the set temperature is based on the temperature detected by a temperature sensor provided at a predetermined position, such as a heating means such as a nip part or a halogen heater, in order to control the fixing temperature at the nip part during fixing. Means the temperature to be determined. Here, when a temperature sensor used to determine the set temperature is provided in the nip portion, the set temperature at the time of fixing can be regarded as an actual average value of the fixing temperature.

  When the image forming apparatus of the present invention is an image forming apparatus having a low fixing temperature, the average value of the actual fixing temperature at the nip portion during fixing (actual average fixing temperature) is 120 ° C. or less. Is preferably 110 ° C. or lower, and more preferably 100 ° C. or lower. If the actual average fixing temperature is too low, it becomes difficult to melt the toner.

The lower the actual average fixing temperature, the greater the energy saving effect. However, when the images are continuously formed, the variation in color tone (coloring property) between the images formed one by one tends to increase. However, even in an apparatus that satisfies the above-described conditions, variation in color tone (coloring property) between images formed on each sheet can be easily suppressed by using the toner of the present invention.
The actual average fixing temperature means an average temperature at the nip portion of the fixing machine at the time of fixing. In this case, in an image forming apparatus that controls the heating means such as a halogen heater in the fixing device by monitoring the temperature of the nip portion, the set temperature for controlling the heating means is substantially the actual average fixing temperature. Can be considered.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
-Adjustment of binder resin fine particle dispersion (1)-
-Styrene: 300 parts by mass-n-butyl acrylate: 190 parts by mass-Acrylic acid: 3 parts by mass-Dodecanethiol: 24 parts by mass-Carbon tetrabromide: 4 parts by mass Non-ionic solution obtained by mixing and dissolving the above components 6 parts by mass of a surfactant (Sanyo Kasei Co., Ltd .: Nonipol 400) and 10 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) were dissolved in 560 parts by mass of ion-exchanged water. In addition to the solution, it was dispersed and emulsified in a flask, and while slowly mixing for 10 minutes, 50 parts by mass of ion-exchanged water in which 4 parts by mass of ammonium persulfate was dissolved was added to perform nitrogen substitution. Subsequently, while stirring in the flask, the contents were heated in an oil bath until the content reached 70 ° C., and emulsion polymerization was continued for 5 hours.
In this way, a binder resin fine particle dispersion (1) obtained by dispersing a binder resin having a volume average particle size of 180 nm and a weight average molecular weight (Mw) of 28,000 was prepared. The water content was adjusted so that the resin fine particle concentration of this dispersion was 10% by mass. The SP value obtained by calculation of the binder resin is 9.93.

-Adjustment of binder resin fine particle dispersion (2)-
In a heat-dried three-necked flask, 98.0 mol% of 1,8 sebacin diacid, 2.0 mol% of sodium dimethyl-5-sulfonate isophthalate as an acid component, and 100 mol% of 1,6 hexanediol as a catalyst Ti (OBu) ₄ (0.014% by mass with respect to the acid component) is added, and then the air in the container is depressurized by a depressurization operation, and is further brought into an inert atmosphere with nitrogen gas. Reflux was carried out at 6 ° C. for 6 hours.

Thereafter, excess ethylene glycol was removed by distillation under reduced pressure, the temperature was gradually raised to 220 ° C., stirred for 4 hours, and when it became viscous, the molecular weight was confirmed by GPC (gel permeation chromatography). When the weight average molecular weight reached 28000, vacuum distillation was stopped and air-cooled to obtain a binder resin. The acid value was 9.8 mgKOH / g.
Subsequently, this resin was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. Separately prepared aqueous medium tank is filled with diluted ammonia water diluted with ion-exchanged water with a concentration of 0.37% by mass and heated to 120 ° C with a heat exchanger at a rate of 0.1 liter per minute Then, it was transferred to the Cavitron simultaneously with the above molten resin.
In this state, the Cavitron was operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² to obtain a binder resin dispersion liquid (2) having a volume average particle size of 0.38 μm. The water content was adjusted so that the resin fine particle concentration of this dispersion was 10% by mass. The SP value obtained by calculation of the binder resin is 9.34.

-Preparation of binder resin fine particle dispersion (3)-
-Bisphenol A ethylene oxide adduct (average number of moles added 2.1): 85 parts by mass-Bisphenol A propylene oxide adduct (average number of moles added 2.2): 217 parts by mass-Fumaric acid: 80 parts by mass-Terephthalic acid : 49 parts by mass After adding 0.12 g of dibutyltin oxide as a catalyst to a solution in which the above components are mixed and dissolved, the pressure in the container is reduced by depressurization, and the atmosphere is made inert with nitrogen gas. At 180 ° C. for 6 hours.
Then, the temperature was gradually raised to 200 ° C. by vacuum distillation and stirred for 5 hours. When the mixture became viscous, the molecular weight was confirmed by GPC. When the weight average molecular weight reached 10,000, the vacuum distillation was stopped. Then, it was air-cooled to obtain a binder resin. Subsequently, this was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. Separately prepared aqueous medium tank is filled with 0.37% by weight diluted ammonia water diluted with ion-exchanged water with reagent-exchanged water and heated at 120 ° C. with a heat exchanger at a rate of 0.1 liter per minute. The melted binder resin was transferred to the Cavitron at the same time.

In this state, the Cavitron was operated under the conditions of the rotor rotation speed of 60 Hz and the pressure of 5 kg / cm ² to obtain a resin fine particle dispersion (3) containing binder resin fine particles having a volume average particle size of 0.14 μm. It was. The water content was adjusted so that the resin fine particle concentration of this dispersion was 10% by mass. The SP value obtained by calculation of the binder resin is 10.1.

-Preparation of binder resin fine particle dispersion (4)-
-Bisphenol A propylene oxide adduct (average addition mole number 2.2): 282 parts by mass-Isophthalic acid: 82 parts by mass-Terephthalic acid: 82 parts by mass A binder resin fine particle dispersion (3 ), A binder resin having a weight average molecular weight of 8500 was obtained. Subsequently, this was emulsified and dispersed with a Cavitron under the same conditions as for the preparation of the binder resin fine particle dispersion (3) to obtain a binder resin fine particle dispersion (4) made of a polyester resin having a volume average particle size of 0.10 μm. The water content was adjusted so that the resin fine particle concentration of this dispersion was 10% by mass. The SP value obtained by calculation of the binder resin is 10.50.

-Adjustment of binder resin fine particle dispersion (5)-
Styrene: 410 parts by mass n butyl acrylate: 50 parts by mass Acrylic acid: 3 parts by mass Dodecanethiol: 6 parts by mass Carbon tetrabromide: 4 parts by mass 6 parts by mass of an ionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) and 12 parts by mass of an anionic surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) are dissolved in 550 parts by mass of ion-exchanged water. The resulting solution was emulsified and dispersed in a flask, and 50 parts by mass of ion-exchanged water in which 3 parts by mass of ammonium persulfate was further dissolved was added while slowly mixing for 10 minutes. Subsequently, after performing nitrogen substitution in the flask, the solution in the flask was heated with an oil bath until the temperature reached 65 ° C. while stirring, and emulsion polymerization was continued for 7 hours.
As a result, a binder resin fine particle dispersion (5) obtained by dispersing a binder resin having a volume average particle size of 200 nm and a weight average molecular weight Mw of 39000 was obtained. The water content was adjusted so that the resin fine particle concentration of this dispersion was 10% by mass. Moreover, SP value calculated | required by calculation of this binder resin is 10.07.

-Adjustment of binder resin fine particle dispersion (6)-
Styrene: 240 parts by mass nbutyl acrylate: 210 parts by mass Acrylic acid: 3 parts by mass Dodecanethiol: 24 parts by mass Carbon tetrabromide: 4 parts by mass 6 parts by weight of a surfactant (Sanyo Kasei Co., Ltd .: Nonipol 400) and 12 parts by weight of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) were dissolved in 540 parts by weight of ion-exchanged water. In addition to the solution, it was dispersed and emulsified in a flask, and while slowly mixing for 10 minutes, 50 parts by mass of ion-exchanged water in which 5 parts by mass of ammonium persulfate was dissolved was added to perform nitrogen substitution. Subsequently, while stirring the inside of the flask, the contents were heated in an oil bath until the temperature reached 75 ° C., and emulsion polymerization was continued for 5 hours.
In this way, a binder resin fine particle dispersion (6) was prepared by dispersing the binder resin having a volume average particle diameter of 192 nm and a weight average molecular weight (Mw) of 31,000. The water content was adjusted so that the resin fine particle concentration of this dispersion was 10% by mass. The SP value obtained by calculation of the binder resin is 9.89.

-Adjustment of binder resin fine particle dispersion (7)-
Bisphenol A propylene oxide adduct (average number of moles added 2.2): 400 parts Trimethylolpropane: 400 parts
-Terephthalic acid: A binder resin having a weight average molecular weight of 23,000 was obtained in the same manner as in the production of the binder resin fine particle dispersion (3) except that 1600 parts or more of the material was used. Subsequently, this was emulsified and dispersed with a Cavitron under the same conditions as for the preparation of the binder resin fine particle dispersion (3) to obtain a binder resin fine particle dispersion (7) made of a polyester resin having a volume average particle size of 0.38 μm. The water content was adjusted so that the resin fine particle concentration of this dispersion was 10% by mass. Moreover, SP value calculated | required by calculation of this binder resin is 10.21.

-Preparation of release agent dispersion-
Paraffin wax (Nippon Seiwa Co., Ltd .: HNP9, melting point 77 ° C.): 60 parts by mass Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 4 parts by mass Ion exchange water: 200 Part by mass A solution in which the above components were mixed was heated to 120 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), then dispersed with a Menton Gorin high-pressure homogenizer (Gorin), and volume averaged. A release agent dispersion was prepared by dispersing a release agent having a particle size of 250 nm. The water content was adjusted so that the release agent concentration of this dispersion was 10% by mass.

-Preparation of colorant dispersion (1)-
Cyan pigment (copper phthalocyanine B15: 3, manufactured by Dainichi Seika Co., Ltd.): 50 parts by mass Nonionic surfactant Nonipol 400 (manufactured by Kao Corporation): 5 parts by mass Ion exchange water: 200 parts by mass After mixing and dissolving, the mixture was dispersed for about 1 hour using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006), and the water content was adjusted to obtain a colorant particle dispersion (1).

-Preparation of colorant dispersion (2)-
-Yellow pigment (CI Pigment Yellow 180): 50 parts by mass-Nonionic surfactant Nonipol 400 (manufactured by Kao Corporation): 5 parts by mass-Ion exchange water: 200 parts by mass Dispersion was carried out for about 6 hours using an impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006), and the water content was adjusted to obtain a colorant particle dispersion (2).

-Production of toner base particles (1)-
Binder resin fine particle dispersion (1): 720 parts by weight Colorant dispersion (1): 50 parts by weight Release agent dispersion (1): 70 parts by weight Cationic surfactant (Kao Corporation) Manufactured: Sanisole B50): 1.5 parts by mass The above components were placed in a round stainless steel flask, and 14 parts by mass of an aqueous nitric acid solution having a polyaluminum chloride concentration of 10% by weight was added as a flocculant.
Thereafter, the mixture was dispersed at 30 ° C. using a homogenizer (manufactured by IKA, Ultra Turrax T50), and then heated to 40 ° C. in an oil bath for heating. The volume average particle size of the obtained core aggregated particles was 5.5 μm as measured using a Coulter counter (TA2 type, manufactured by Coulter Inc.).

After this aggregated particle dispersion was held at 40 ° C. for 30 minutes, 160 parts by mass of binder resin fine particle dispersion (4) was gently added to the dispersion in which the core aggregated particles were formed, and held for 1 hour. It was 5.8 micrometers when it measured using the Coulter counter (Coulter company make, TA2 type | mold) about the obtained adhesion resin aggregation particle | grains. Furthermore, it heated to 80 degreeC, continuing stirring, and hold | maintained for 3 hours.
Thereafter, the mixture was cooled to 20 ° C. at a rate of 1 ° C./min, filtered, washed with ion-exchanged water, and then dried using a vacuum dryer to obtain toner mother particles having a core-shell structure. The obtained toner base particles were measured using a Coulter counter (TA2 type, manufactured by Coulter, Inc.), and the volume average particle diameter was 5.7 μm.

-Production of toner base particles (2)-
-Binder resin fine particle dispersion (1): 680 parts by mass-Colorant dispersion (2): 100 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant (manufactured by Kao Corporation: SANISOL B50): 1.5 parts by mass A core-shell structure having a volume average particle size of 6.3 μm is obtained in the same manner as the toner base particles (1) except that the above dispersions are used for forming the core aggregated particles. Toner mother particles were prepared.

-Production of toner base particles (3)-
Binder resin fine particle dispersion (2): 150 parts by mass Binder resin fine particle dispersion (3): 500 parts by mass Binder resin fine particle dispersion (7): 30 parts by mass Colorant dispersion (1) : 50 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant (manufactured by Kao Corporation: Sanisol B50): 1.5 parts by mass The above ingredients are put into a round stainless steel flask. Thereafter, 16 parts by mass of an aqueous nitric acid solution having a polyaluminum chloride concentration of 10% by weight was added as a flocculant. Thereafter, the mixture was dispersed at 30 ° C. using a homogenizer (manufactured by IKA, Ultra Turrax T50), and then heated to 45 ° C. in an oil bath for heating. It was 5.2 micrometers when the volume average particle diameter of the obtained core aggregated particle was measured using the Coulter counter (Coulter company make, TA2 type | mold).

Further, the mixture was heated to 95 ° C. while continuing stirring and held for 2 hours to fuse the core aggregated particles to obtain core fused particles. Then, it cooled to 20 degreeC with the speed | rate of 20 degreeC / min, and this was filtered, and the moisture content was set to 35 mass%. Nitric acid aqueous solution 32 having a polyaluminum chloride concentration of 10% by mass while gently adding 200 parts by mass of binder resin fine particle dispersion (4) to the dispersion containing 35% by mass core fusion particles and stirring. Mass parts were added and held for 240 minutes. The obtained adhered resin aggregated particles were washed with ion-exchanged water, and then dried using a vacuum dryer.
Further, the adhered resin agglomerated particles were fused by stirring for 20 minutes with a Henschel mixer to obtain toner mother particles having a core-shell structure. When the toner base particles were measured using a Coulter counter (TA2 type, manufactured by Coulter, Inc.), the volume average particle diameter was 6.9 μm.

-Production of toner base particles (4)-
Binder resin fine particle dispersion (2): 150 parts by mass Binder resin fine particle dispersion (3): 480 parts by mass Colorant dispersion (2): 100 parts by mass Release agent dispersion (1): 70 parts by mass / cationic surfactant (manufactured by Kao Corporation: Sanizol B50): 1.5 parts by mass Further, fused particles having a volume average particle diameter of 6.8 μm were prepared.

-Production of toner base particles (5)-
-Binder resin fine particle dispersion (1): 560 parts by mass-Colorant dispersion (1): 50 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant (manufactured by Kao Corporation) : Sanisol B50): 1.5 parts by mass The above components were placed in a round stainless steel flask, and 14 parts by mass of an aqueous nitric acid solution having a polyaluminum chloride concentration of 10% by weight was added as a flocculant. Thereafter, the mixture was dispersed at 30 ° C. using a homogenizer (manufactured by IKA, Ultra Turrax T50), and then heated to 40 ° C. in an oil bath for heating. It was 5.6 micrometers when the volume average particle diameter of the obtained aggregated particle was measured using the Coulter counter (Coulter company make, TA2 type).

The dispersion in which the aggregated particles were formed was held at 40 ° C. for 30 minutes, and then 320 parts by mass of the binder resin fine particle dispersion (5) was gently added to the dispersion and held for 3 hours.
The volume average particle diameter of the obtained adhered resin aggregated particles was measured using a Coulter counter (TA2 type, manufactured by Coulter, Inc.), and was 6.3 μm. Furthermore, it heated to 95 degreeC, continuing stirring, and hold | maintained for 5 hours. Thereafter, the mixture was cooled to 20 ° C. at a rate of 1 ° C./min, filtered, washed with ion-exchanged water, and then dried using a vacuum dryer to obtain toner mother particles having a core-shell structure.
The obtained toner base particles were measured using a Coulter counter (TA2 type, manufactured by Coulter Inc.), and the volume average particle diameter was 6.2 μm.

-Production of toner base particles (6)-
-Binder resin fine particle dispersion (1): 510 parts by mass-Colorant dispersion (2): 100 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant (manufactured by Kao Corporation) : Sanisol B50): 1.5 parts by mass Except that the above dispersion liquids were used for forming the core aggregated particles, it was prepared in the same manner as the toner base particles (5), and the volume average particle size was 5.9 μm. Toner mother particles having a core-shell structure were obtained.

-Production of toner base particles (7)-
-Binder resin fine particle dispersion (2): 350 parts by mass-Colorant dispersion (1): 50 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant-(Kao Corporation) Manufactured: Sanisole B50): 1.5 parts by mass The above components were placed in a round stainless steel flask, and 12 parts by mass of an aqueous nitric acid solution having a polyaluminum chloride concentration of 10% by mass was added as a flocculant. Thereafter, the mixture was dispersed at 30 ° C. using a homogenizer (manufactured by IKA, Ultra Turrax T50), and then heated to 45 ° C. in an oil bath for heating. The volume average particle diameter of the obtained aggregated particles was measured using a Coulter counter (TA2 type, manufactured by Coulter, Inc.), and was 5.3 μm.

The dispersion in which the aggregated particles were formed was held at 45 ° C. for 60 minutes, and then 530 parts by mass of the binder resin fine particle dispersion (4) was gently added to the dispersion and held for 120 minutes.
The volume average particle size of the obtained adhered resin aggregated particles was measured with a Coulter counter (TA2 type, manufactured by Coulter, Inc.), and was 6.2 μm. Furthermore, it heated to 95 degreeC, continuing stirring, and hold | maintained for 2 hours. Thereafter, the mixture was cooled to 20 ° C. at a rate of 10 ° C./min, filtered, washed with ion-exchanged water, and then dried using a vacuum dryer to obtain toner mother particles having a core-shell structure.
The obtained toner base particles were measured using a Coulter counter (TA2 type, manufactured by Coulter, Inc.). The volume average particle diameter (D50%) was 6.3 μm.

-Production of toner base particles (8)-
-Binder resin fine particle dispersion (2): 350 parts by mass-Colorant dispersion (2): 100 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant (manufactured by Kao Corporation) : Sanisol B50): 1.5 parts by mass Toner base particles (7) except that the above dispersions were used for forming core aggregated particles, and the amount of the binder resin fine particle dispersion (4) was changed to 480 parts by mass. ) To obtain toner base particles having a core-shell structure with a volume average particle diameter of 5.8 μm.

-Production of toner base particles (9)-
-Binder resin fine particle dispersion (2): 200 parts by mass-Colorant dispersion (1): 50 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant-(Kao Corporation) Manufactured: Sanisole B50): 1.5 parts by mass The above components were placed in a round stainless steel flask, and 18 parts by mass of an aqueous nitric acid solution having a polyaluminum chloride concentration of 10% by mass was added as a flocculant.

Then, after dispersing at 30 ° C. using a homogenizer (manufactured by IKA, Ultra Tarrax T50), 680 parts by mass of the binder resin fine particle dispersion (5) is gradually added to the core aggregated particle dispersion. Held for a minute. While continuing stirring, the mixture was heated to 95 ° C. at a rate of 0.5 ° C./min and held at 95 ° C. for 3 hours.
Thereafter, the mixture was cooled to 20 ° C. at a rate of 10 ° C./min, filtered, washed with ion-exchanged water, and then dried using a vacuum dryer to obtain toner mother particles having a core-shell structure. The obtained toner base particles were measured using a Coulter counter (TA2 type, manufactured by Coulter Inc.), and the volume average particle diameter was 6.5 μm.

-Production of toner base particles (10)-
-Binder resin fine particle dispersion (2): 150 parts by mass-Colorant dispersion (2): 100 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant-(Kao Corporation) Manufactured by: Sanisol B50): 1.5 parts by mass Toner base particles except that the above dispersions are used for forming core aggregated particles and the amount of the binder resin fine particle dispersion (5) is 680 parts by mass. Produced in the same manner as (9), toner mother particles having a core-shell structure with a volume average particle size of 6.8 μm were obtained.

-Production of toner base particles (11)-
-Binder resin fine particle dispersion (2): 300 parts by mass-Binder resin fine particle dispersion (3): 380 parts by mass-Colorant dispersion (1): 50 parts by mass-Release agent dispersion (1): 70 parts by mass / cationic surfactant (manufactured by Kao Corporation: Sanizol B50): 1.5 parts by mass After the above components were placed in a round stainless steel flask, the concentration of polyaluminum chloride as a flocculant was 10% by weight. 16 parts by mass of an aqueous nitric acid solution was added. Thereafter, the mixture was dispersed at 30 ° C. using a homogenizer (manufactured by IKA, Ultra Turrax T50), and then heated to 45 ° C. in an oil bath for heating. It was 5.2 micrometers when the volume average particle diameter of the obtained core aggregated particle was measured using the Coulter counter (Coulter company make, TA2 type | mold). Further, the mixture was heated to 85 ° C. and kept for 2 hours while continuing stirring, and then heated to 95 ° C. and kept for 1 hour to fuse the core aggregated particles to obtain core fused particles.

Then, it cooled to 20 degreeC with the speed | rate of 20 degreeC / min, and this was filtered, and the moisture content was set to 35 mass%. While adding 200 parts by mass of the binder resin fine particle dispersion (4) to the dispersion containing the core fusion particles having a moisture content of 35% by mass and stirring the nitric acid aqueous solution 20 having a polyaluminum chloride concentration of 10% by mass. Mass parts were added and held for 240 minutes. The obtained adhered resin aggregated particles were washed with ion-exchanged water and dried using a vacuum dryer.
Further, the adhered resin agglomerated particles were fused by stirring for 20 minutes with a Henschel mixer to obtain toner mother particles having a core-shell structure. When the toner base particles were measured using a Coulter counter (TA2 type, manufactured by Coulter, Inc.), the volume average particle diameter was 6.5 μm.

-Production of toner base particles (12)-
-Binder resin fine particle dispersion (2): 300 parts by mass-Binder resin fine particle dispersion (3): 330 parts by mass-Colorant dispersion (2): 100 parts by mass-Release agent dispersion (1): 70 parts by mass / cationic surfactant (manufactured by Kao Corporation: Sanizol B50): 1.5 parts by mass The same as the toner base particles (11) except that the above dispersions were used for forming the core aggregated particles. Thus, toner mother particles having a core-shell structure with a volume average particle diameter of 6.8 μm were obtained.

-Production of toner base particles (13)-
-Binder resin fine particle dispersion (2): 480 parts by mass-Binder resin fine particle dispersion (3): 350 parts by mass-Colorant dispersion (1): 50 parts by mass-Release agent dispersion (1): 70 parts by mass / cationic surfactant (manufactured by Kao Corporation: Sanisol B50): 1.5 parts by mass The above components are contained in a round stainless steel flask, and the concentration of polyaluminum chloride as a flocculant is 10% by weight. 14 parts by mass of an aqueous nitric acid solution was added. Thereafter, the mixture was dispersed at 30 ° C. using a homogenizer (manufactured by IKA, Ultra Turrax T50), and then heated to 40 ° C. in an oil bath for heating. The volume average particle size of the obtained aggregated particles was 5.2 μm as measured using a Coulter counter (TA2 type, manufactured by Coulter, Inc.). The dispersion in which the aggregated particles were formed was held at 40 ° C. for 30 minutes, and then 50 parts by mass of the binder resin fine particle dispersion (7) was gently added to the dispersion and held for 30 minutes.

  The volume average particle diameter of the obtained adhered resin aggregated particles was measured to be 5.7 μm using a Coulter counter (TA2 type, manufactured by Coulter Inc.). Further, the mixture was heated to 96 ° C. while continuing stirring and maintained for 5 hours. Thereafter, the mixture was cooled to 20 ° C. at a rate of 1 ° C./min, filtered, washed with ion-exchanged water, and then dried using a vacuum dryer to obtain toner mother particles having a core-shell structure. The obtained toner base particles were measured using a Coulter counter (TA2 type, manufactured by Coulter, Inc.), and the volume average particle diameter was 6.0 μm.

-Production of toner base particles (14)-
-Binder resin fine particle dispersion (2): 480 parts by mass-Binder resin fine particle dispersion (3): 300 parts by mass-Colorant dispersion (2): 100 parts by mass-Release agent dispersion (1): 70 parts by mass / cationic surfactant (manufactured by Kao Corporation: Sanizol B50): 1.5 parts by mass The same as the toner base particles (13) except that the above dispersions were used for forming the core aggregated particles Thus, toner mother particles (14) having a core-shell structure with a volume average particle diameter of 6.1 μm were obtained.

-Production of toner base particles (15)-
-Binder resin fine particle dispersion (3): 630 parts by mass-Colorant dispersion (1): 50 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant (manufactured by Kao Corporation) : Sanisol B50): 1.5 parts by mass After the above components were put in a round stainless steel flask, 16 parts by mass of an aqueous nitric acid solution having a polyaluminum chloride concentration of 10% by weight was added as a flocculant. Thereafter, the mixture was dispersed at 20 ° C. using a homogenizer (manufactured by IKA, Ultra Turrax T50), and then heated to 35 ° C. in an oil bath for heating. Thereafter, 250 parts by mass of the binder resin fine particle dispersion (2) was gently added and held for 2 hours with stirring. Further, while stirring, the mixture was heated to 75 ° C. and held for 5 hours to fuse the core aggregated particles to obtain toner base particles having a core-shell structure. When the toner base particles were measured using a Coulter counter (TA2 type, manufactured by Coulter, Inc.), the volume average particle diameter was 6.5 μm.

-Production of toner base particles (16)-
-Binder resin fine particle dispersion (3): 580 parts by mass-Colorant dispersion (1): 100 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant (manufactured by Kao Corporation) : Sanisol B50): 1.5 parts by mass A core shell having a volume average particle size of 6.3 μm, prepared in the same manner as the toner base particles (15) except that the above dispersions were used for forming the core aggregated particles. Toner mother particles (16) having a structure were obtained.

-Production of toner base particles (17)-
-Binder resin fine particle dispersion (7): 680 parts by mass-Colorant dispersion (1): 50 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant (manufactured by Kao Corporation) : Sanisol B50): 1.5 parts by mass The above components were placed in a round stainless steel flask, and 14 parts by mass of an aqueous nitric acid solution having a polyaluminum chloride concentration of 10% by weight was added as a flocculant. Thereafter, the mixture was dispersed at 30 ° C. using a homogenizer (manufactured by IKA, Ultra Turrax T50), and then heated to 40 ° C. in an oil bath for heating. The volume average particle diameter of the obtained aggregated particles was 5.1 μm as measured using a Coulter counter (TA2 type, manufactured by Coulter Inc.). The dispersion in which the aggregated particles were formed was held at 40 ° C. for 30 minutes, and then 200 parts by mass of the binder resin fine particle dispersion (5) was gently added to the dispersion and held for 90 minutes.

  The volume average particle diameter of the obtained adhered resin aggregated particles was measured to be 5.9 μm using a Coulter counter (TA2 type, manufactured by Coulter Inc.). Furthermore, it heated to 90 degreeC, continuing stirring, and hold | maintained for 2 hours. Thereafter, the mixture was cooled to 20 ° C. at a rate of 1 ° C./min, filtered, washed with ion-exchanged water, and then dried using a vacuum dryer to obtain toner mother particles having a core-shell structure. The obtained toner base particles were measured using a Coulter counter (TA2 type, manufactured by Coulter Inc.), and the volume average particle diameter was 6.2 μm.

-Production of toner base particles (18)-
-Binder resin fine particle dispersion (7): 630 parts by mass-Colorant dispersion (2): 100 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant (manufactured by Kao Corporation) : Sanisol B50): 1.5 parts by mass A core shell having a volume average particle size of 6.9 μm, prepared in the same manner as the toner mother particles (17) except that the above dispersions were used for forming the core aggregated particles. Toner mother particles having a structure were obtained.

-Production of toner base particles (19)-
-Binder resin fine particle dispersion (1): 670 parts by mass-Colorant dispersion (1): 50 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant (manufactured by Kao Corporation) : Sanisol B50): 1.5 parts by mass The above components were placed in a round stainless steel flask, and 14 parts by mass of an aqueous nitric acid solution having a polyaluminum chloride concentration of 10% by weight was added as a flocculant. Thereafter, the mixture was dispersed at 30 ° C. using a homogenizer (manufactured by IKA, Ultra Turrax T50), and then heated to 40 ° C. in an oil bath for heating. The volume average particle size of the obtained aggregated particles was 4.7 μm as measured using a Coulter counter (TA2 type, manufactured by Coulter Inc.). The dispersion in which the aggregated particles were formed was held at 40 ° C. for 60 minutes, and then 210 parts by mass of the binder resin fine particle dispersion (7) was gently added to the dispersion and held for 30 minutes.

  The volume average particle diameter of the obtained adhered resin aggregated particles was measured to be 5.7 μm using a Coulter counter (TA2 type, manufactured by Coulter Inc.). Furthermore, it heated to 90 degreeC, continuing stirring, and hold | maintained for 5 hours. Thereafter, the mixture was cooled to 20 ° C. at a rate of 1 ° C./min, filtered, washed with ion-exchanged water, and then dried using a vacuum dryer to obtain toner mother particles having a core-shell structure. The obtained toner base particles were measured using a Coulter counter (TA2 type, manufactured by Coulter Inc.), and the volume average particle diameter was 5.8 μm.

-Production of toner base particles (20)-
-Binder resin fine particle dispersion (1): 620 parts by mass-Colorant dispersion (2): 100 parts by mass-Release agent dispersion (1): 70 parts by mass-Cationic surfactant (manufactured by Kao Corporation) : Sanisol B50): 1.5 parts by mass A core shell having a volume average particle size of 5.7 μm, prepared in the same manner as the toner base particles (13) except that the above dispersions were used for forming the core aggregated particles. Toner mother particles (14) having a structure were obtained.

Table 1 shows the characteristics of the binder resin used for the production of each toner base particle.
Here, since toner core particles 3, 4, 11, 12, 13, and 14 are used by mixing a plurality of types of binder resins for the core layer, viscoelasticity is measured by separately blending two types of resins. The values were listed. Further, regarding the toner base particles 3, 4, 11, 12, 13, and 14, the SP value of the resin blend for core layer is unknown and therefore not described.

<Various toner evaluation>
(Manufacture of carriers)
Ferrite particles (volume average particle size: 50 μm): 100 parts by mass Toluene: 14 parts by mass Styrene-methyl methacrylate copolymer (component ratio: styrene / methyl methacrylate = 90/10, weight average molecular weight Mw = 80000): 2 parts by mass / carbon black (R330: manufactured by Cabot): 0.2 part by mass First, the above components excluding ferrite particles are stirred with a stirrer for 10 minutes to prepare a dispersed coating solution, and then this coating solution And ferrite particles were placed in a vacuum degassing type kneader, stirred at 60 ° C. for 30 minutes, degassed by further depressurization while heating, and dried to obtain a carrier.

(Development of developer)
1.2 parts by mass of commercially available fumed silica RX50 (manufactured by Nippon Aerosil Co., Ltd.) as an external additive is added to each of the toner base particles (1) to (20) with respect to 100 parts by mass of the toner. Toners for charge image development (1) to (20) were obtained.
Subsequently, 5 parts by mass of each of these toners and 100 parts by mass of the carrier were mixed to prepare two-component developers (1) to (20).

(Measurement of viscoelasticity)
The storage elastic modulus was obtained from dynamic viscoelasticity measured by a sinusoidal vibration method. For measurement of dynamic viscoelasticity, an ARES measuring apparatus manufactured by Rheometric Scientific was used. The measurement of dynamic viscoelasticity was carried out by setting the toner molded into a tablet on a parallel plate of 8 mm diameter, setting the normal force to 0, and then applying sine wave vibration at a vibration frequency of 6.28 rad / sec. The measurement started from 20 ° C and continued to 100 ° C. The measurement time interval was 30 seconds, and the temperature rise was 1 ° C./min.
Before the measurement, the stress dependence of the strain amount was confirmed at intervals of 10 ° C. from 20 ° C. to 100 ° C., and the strain amount range in which the stress and the strain amount at each temperature are in a linear relationship was obtained. During the measurement, the strain amount at each measurement temperature is maintained in the range of 0.01% to 0.5%, and the stress and the strain amount are controlled to have a linear relationship at all temperatures, and the storage elastic modulus and Tangent loss was determined.

(Volume average particle size)
When measuring the volume average particle diameter of the toner, a Coulter Counter TA-2 (manufactured by Beckman-Coulter) was used, and ISOTON-II (manufactured by Beckman-Coulter) was used as the electrolyte.
First, 0.5 to 50 mg of a measurement sample was added to 2 ml of a surfactant, preferably a 5% by weight aqueous solution of sodium alkylbenzenesulfonate as a dispersant, and a sample was prepared by adding this to 100 to 150 ml of the electrolytic solution.

Subsequently, the electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and by the Coulter counter TA-II type, an aperture having an aperture diameter of 100 μm is used. The particle size distribution of the particles was measured to obtain a volume average distribution and a number average distribution.
For the particle size range (channel) into which the measured particle size distribution was divided, a cumulative distribution was drawn from the small diameter side on a volume basis, and the particle size (D50v) at 50% accumulation was defined as the volume average particle size.

Example 1
Fixing evaluation was carried out using developer (1) and developer (2).

(Example 2)
Fixing evaluation was carried out using developer (3) and developer (4).

(Example 3)
Fixation evaluation was carried out using developer (11) and developer (12).

Example 4
Fixing evaluation was carried out using developer (19) and developer (20).

(Comparative Example 1)
Fixing evaluation was carried out using developer (5) and developer (6).

(Comparative Example 2)
Fixing evaluation was performed using developer (7) and developer (8).

(Comparative Example 3)
Fixing evaluation was performed using developer (9) and developer (10).

(Comparative Example 4)
Fixing evaluation was carried out using developer (13) and developer (14).

(Comparative Example 5)
Fixation evaluation was carried out using developer (15) and developer (16).

(Comparative Example 6)
Fixing evaluation was carried out using developer (17) and developer (18).

-Evaluation results-
Table 2 shows the evaluation results of the viscoelasticity of the toner for developing an electrostatic image and the evaluation results of the low-temperature fixability / color reproducibility.

As can be seen from the results in Table 2, Examples 1 to 4 can be fixed at a low temperature of 100 ° C. or lower, and the color reproducibility at the time of continuous output is also stable. However, in Comparative Example 1, the storage elastic modulus at 60 ° C. is higher than 4.0 × 10 ⁶ Pa, and the ratio G of the storage elastic modulus G ′ (60) at 60 ° C. and the storage elastic modulus G ′ (80) at 80 ° C. Since “(60) / G” (80) is larger than 40.0, low-temperature fixing is difficult.
In Comparative Example 2, the storage elastic modulus at 60 ° C. is 2.0 × 10 ⁵ Pa or more and 4.0 × 10 ⁶ Pa or less, but the ratio G ′ (60) / G ′ of the storage elastic modulus G ′ (80). Since (80) is larger than 40, low-temperature fixing is possible, but color reproducibility during continuous output is not stable.

In Comparative Example 3, the ratio G ′ (60) / G ′ (80) of the storage elastic modulus G ′ (80) is 40 or less, but the storage elastic modulus at 60 ° C. is higher than 4.0 × 10 ⁶ Pa. The color reproducibility during continuous output at low temperature fixing is not stable.
In Comparative Examples 1 to 6, since the combination of the viscoelasticity of the binder resin for the core layer and the binder resin for the shell layer and the control of the SP value are not appropriate, the peak number of the tangent loss becomes one, and the low temperature fixing and the continuous output are performed. It is thought that the reproducibility of color development at the time cannot be achieved.

The apparatus used for the evaluation of the low-temperature fixability and the color reproducibility shown in Table 2, the evaluation method and the evaluation criteria for the low-temperature fixability and the color reproducibility are as follows.
(Image forming device)
For the evaluation, a modified machine of DocuPrint C2221 manufactured by Fuji Xerox was used. This apparatus incorporates a 900 W halogen lamp in a heating roll as heating means for the nip portion in the fixing machine, and the fixing temperature set in the fixing machine can be varied in the range of 70 ° C to 200 ° C. The heat capacity of the heating roll of the fixing machine is 67.5 J / ° C.
In addition, this apparatus has a standby power saving function. When the fixing temperature setting of the fixing device is set to 115 ° C., the standby temperature setting for standby is 95 ° C. with respect to image formation (fixing time). The difference between the set temperature at the (nip portion) during fixing and the set temperature at the (nip portion) during standby is 20 ° C.
Further, the warm-up time when the set fixing temperature of the fixing device is set to 115 ° C. is about 15 seconds. Note that the warm-up time is a time required until an image can be formed when an image is formed from a standby state, and substantially corresponds to a time from the set standby temperature to the set fixing temperature. .

(Low-temperature fixability evaluation)
Fixation evaluation was performed using a modified machine of DocuPrint C2221 manufactured by Fuji Xerox. The evaluation was performed with a secondary color (Green) in which cyan toner and yellow toner were superimposed.
In the evaluation, first, the machine was adjusted so that the amount of monochromatic toner was 4.8 g / m ² on paper (J paper manufactured by Fuji Xerox), and a yellow color toner layer was formed on the cyan color toner layer. Then, an unfixed solid image of Green color of 25 mm × 25 mm was produced.
Next, using the sheet on which the unfixed solid image was formed, the unfixed image was fixed while gradually increasing the fixing temperature of the fixing device between 70 ° C. and 200 ° C. to obtain a fixed image.

An offset of an image produced at a fixing temperature of 70 ° C. to 200 ° C. was visually evaluated. The temperature at which no offset occurred at a low temperature was evaluated as the minimum fixing temperature. The evaluation criteria for low-temperature fixability are as follows.
A: Minimum fixing temperature is 100 ° C. or lower. ○: Minimum fixing temperature exceeds 100 ° C. and lower than 110 ° C. Δ: Minimum fixing temperature is 110 to 120 ° C. ×: Minimum fixing temperature is 120 ° C. or higher.

(Evaluation of color reproducibility)
Fixation evaluation was performed using a modified machine of DocuPrint C2221 manufactured by Fuji Xerox. The evaluation was performed with a secondary color (Green) in which cyan toner and yellow toner were superimposed.
Adjust the machine so that the amount of monochromatic toner is 4.5 g / m ² on paper (J paper manufactured by Fuji Xerox), and form a yellow color toner layer on the cyan color toner layer. A green-colored unfixed solid image was produced.
Next, after the standby state was sufficiently maintained until the temperature of the fixing device reached a steady state, 30 sheets were continuously fixed from the standby state at a set fixing temperature of 115 ° C. The color developability of the fixed image was evaluated using X-Rite 528 (manufactured by X-Rite).

One by one in the obtained image, measuring the C ^*, the difference between the maximum value of C ^* in 30 sheets ((C ^* _MAX) and minimum value _{^{(C * MIN) ΔC (=}} C * MAX - C ^* _MIN ) where the smaller ΔC, the smaller the variation in color developability for each sheet during continuous output.The C ^* measurement is performed at 5 points in the 25 mm × 25 mm image plane. The average value was obtained by measurement.
The specific evaluation criteria are as follows.
◎: ΔC is 2 or less ○: ΔC exceeds 2 and 3 or less Δ: ΔC is 3 or more and less than 5 ×: ΔC is 5 or more

C ^* is a value represented by the following formula (4).
Formula (4) C ^* = (a ^{* 2} + b ^{* 2} ) ^1/2
Here, a * and b * mean a * and b * in the L * a * b * color system defined in JISZ8729.

(Evaluation of warm-up time)
Note that the warm-up time was evaluated by changing the combination of the heat capacity, the set temperature, and the standby temperature of the fixing member of the DocuPntt C2221 modified machine manufactured by Fuji Xerox, which was used for the evaluation of the low-temperature fixability. Table 3 shows combinations of heat capacity and standby temperature of the fixing machine.
From Table 3, it can be seen that, compared with the image forming apparatuses C and D, the image forming apparatuses A and B have a low standby temperature, excellent energy saving, and a short warm-up time.

Claims (4)

In an electrostatic charge image developing toner having a core layer containing a first binder resin and a colorant, and a shell layer containing a second binder resin and covering the core layer,
An electrostatic image developing toner characterized by satisfying the following formulas (1) and (2):
Formula (1) 2.0 × 10 ⁵ ≦ G ′ (60) ≦ 4.0 × 10 ⁶
Formula (2) 10 ≦ G ′ (60) / G ′ (80) ≦ 40
[In Formula (1) and Formula (2), G ′ (60) is the electrostatic charge image measured under the conditions of a temperature of 60 ° C., a vibration frequency of 6.28 rad / sec, and a strain amount of 0.01 to 0.5%. This represents the storage elastic modulus (Pa) of the developing toner, and G ′ (80) is the electrostatic charge measured under the conditions of a temperature of 80 ° C., a vibration frequency of 6.28 rad / sec, and a strain amount of 0.01 to 0.5%. The storage elastic modulus (Pa) of the toner for image development is represented. ] At least a first resin fine particle dispersion made of the first binder resin and having a volume average particle diameter of 1 μm or less dispersed therein and a colorant dispersion containing the colorant dispersed therein are mixed at least. An aggregating step of adding a flocculant to the mixed dispersion and heating to form core particles;
To the mixed dispersion in which the core particles are formed, a second resin fine particle dispersion in which second resin fine particles made of the second binder resin and having a volume average particle size of 1 μm or less are dispersed is added. An attachment step of attaching the second resin fine particles to the surface of the core particles to form attached resin agglomerated particles;
The method for producing an electrostatic charge image developing toner according to claim 1, further comprising a fusing step of fusing the adhered resin aggregated particles.   An electrostatic charge image developing developer comprising the electrostatic charge image developing toner according to claim 1. An image bearing member; a charging unit that charges the surface of the image bearing member; an exposure unit that forms an electrostatic latent image according to image information on the charged surface of the image bearing member; And developing means for forming a toner image on the surface of the image carrier, transfer means for transferring the toner image from the surface of the image carrier to the surface of the recording medium, and transferring to the surface of the recording medium. An image forming apparatus including a fixing unit that heats and pressurizes the toner image thus formed to form an image;
The image forming apparatus according to claim 1, wherein the toner is an electrostatic image developing toner according to claim 1.