JP5228753B2 - Toner set, electrostatic latent image developer set, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a toner set, an electrostatic latent image developer set, a process cartridge, and an image forming apparatus.

Conventionally, in a color image forming apparatus that forms a color image by an electrophotographic method or an electrostatic recording method, a color image is formed on the surface of a recording medium. For example, when a color copy is made, the following image formation is performed. Process operations are performed.
That is, the color original is illuminated, the reflected light image is color-separated and read by a color scanner, subjected to predetermined image processing and color correction by an image processing device, and based on the obtained multiple-color image signals, for example, a semiconductor A laser or the like is modulated, and a laser beam modulated in accordance with an image signal is emitted from the semiconductor laser. By irradiating the surface of the image carrier, which is composed of an inorganic photoreceptor such as Se or amorphous silicon, or an organic photoreceptor using a phthalocyanine pigment, a bisazo pigment, or the like as a charge generation layer, a plurality of times each color, An electrostatic latent image is formed.

  Each of the plurality of electrostatic latent images is successively developed with, for example, four color toners of yellow (Y), magenta (M), cyan (C), and black (K). Then, the developed toner image is transferred from an image carrier made of an inorganic or organic photoconductor to a surface of a recording medium such as paper, and fixed by, for example, a fixing device of a heat and pressure fixing system. In this way, a color image is formed on the surface of the recording medium.

In these color image formations, proposals have been made to use a color copying machine and appropriately select the material of the toner, fixing conditions, and the like (see, for example, Patent Documents 1 to 3).
In addition to the conventional Y (yellow), M (magenta) C (cyan), and BK (black), a transparent toner is used to correct the gloss difference in the image surface, or on the same transfer paper surface. Attempts have been made to arbitrarily control gloss and to correct image density and toner adhesion. Specifically, an image forming method for providing a color image with different glossiness in a desired area of a recording medium using transparent toner (see, for example, Patent Document 4), an image in which a transparent toner image is superimposed on a color toner image A forming method (see, for example, Patent Document 5) has been proposed.

Further, an image forming method in which the surface property of an image is arbitrarily selected locally or entirely by a transparent toner layer (see, for example, Patent Document 6), and recording using a toner containing a near infrared absorbing material. An image forming method for forming an invisible image on a medium together with a color image (for example, see Patent Documents 7 and 8), and an image forming method using a toner containing a binder resin whose main component is a crystalline polyester resin (for example, Patent Document 9) And 10) are proposed respectively.
JP-A-5-142963 Japanese Patent Laid-Open No. 8-220821 JP-A 63-259575 Japanese Patent Laid-Open No. 8-220821 JP-A-10-207174 JP-A-5-232840 JP 2007-3942 A JP 2007-171508 A JP 2007-316419 A JP 2007-328295 A

  In the formation of a color image as described above, the surface of the paper as a recording medium is usually glossy while the surface of the paper as a recording medium is glossy to some extent because the surface is smoothed during heat fixing. The color image has a glossiness different from that of the paper surface. In addition, it is known that the viscosity of the toner at the time of heat fixing changes due to the type of binder resin used for the color toner, the method of heat fixing, and the like, and the glossiness of the color image changes.

By the way, the preference for the glossiness of a color image varies depending on the type and purpose of use of the image, and there are a wide variety. High gloss images tend to be preferred.
In the techniques proposed in Patent Documents 1 to 3, the glossiness of the image portion by toner can be increased, but the glossiness of the non-image portion including the halftone portion cannot be increased. The glossiness cannot be made uniform. Further, the unevenness of the color toner remains on the surface of the image and does not become smooth like a silver salt photograph or printing, so that there is a problem that a smooth texture cannot be obtained.

  The techniques proposed in Patent Documents 4 to 6 all propose an image forming method using a transparent toner. In any of the inventions, a toner in a low-density image area is obtained by using a transparent toner. It is proposed to eliminate the uncomfortable feeling of the conventional color image quality by increasing the amount of adhesion, or by obtaining a uniform gloss by covering the entire image surface with transparent toner. However, unless the melting property of the toner used is optimally controlled, the desired effect is not exhibited.

  Further, in the image forming methods proposed in Patent Documents 7 and 8, the color toner image has a high gloss and the invisible image has a low gloss similar to a recording medium, and controls the gloss of the color toner image portion. However, even if an invisible image is used on the color toner image portion, the gloss is too low. That is, normally, a transparent toner that contains little or no colorant compared to Y, M, C, and BK toners that contain a large amount of colorant naturally has different dynamic melting characteristics at the time of fixing. Even if a transparent toner is used without properly controlling the melting characteristics, if a transparent toner layer is provided on a color toner layer made of Y, M, C, and BK toners, an image defect called a toner blister occurs due to fixing. Or an image defect that a high-gloss fixed image cannot be obtained. In addition, the image forming methods proposed in Patent Documents 9 and 10 have high gloss and can suppress narblister, but the strength of the fixed image is inferior.

  The present invention relates to a toner set capable of obtaining a stable image with high gloss, excellent color reproducibility, and no occurrence of toner blisters without impairing the strength of a fixed image, and an electrostatic latent image developer set including the toner set Another object of the present invention is to provide a process cartridge and an image forming apparatus using the electrostatic latent image developer set.

The above-mentioned subject is achieved by the following present invention.
That is, the invention according to claim 1
It is composed of one or more color toners selected from the group consisting of magenta toner, cyan toner and yellow toner, and transparent toner,
The color toner has a storage elastic modulus (G1) at 80 ° C. of 10 ⁴ Pa to 10 ⁶ Pa,
Tangent loss (tan δ) at 80 ° C. of the color toner is 1.0 or more and 2.5 or less,
The toner set is characterized in that the storage elastic modulus (G2) of the transparent toner at 80 ° C. and the storage elastic modulus (G1) of the color toner at 80 ° C. satisfy the relationship of the following formula (1).
1.1 ≦ G2 / G1 ≦ 3.0 (1)

The invention according to claim 2
The color toner and the transparent toner each contain a divalent or higher metal element, and the amount of the divalent or higher metal element contained in the transparent toner is greater than the amount of the divalent or higher metal element contained in the color toner. The toner set according to claim 1, wherein the toner set is large.

The invention according to claim 3
The color toner and the transparent toner each contain a crystalline resin, and the content of the crystalline resin in each toner is 4% by mass or more and 20% by mass or less. The toner set described above.

The invention according to claim 4
It is composed of a developer that includes at least one color toner selected from the group consisting of magenta toner, cyan toner, and yellow toner, and transparent toner,
The color toner has a storage elastic modulus (G1) at 80 ° C. of 10 ⁴ Pa to 10 ⁶ Pa,
Tangent loss (tan δ) at 80 ° C. of the color toner is 1.0 or more and 2.5 or less,
The electrostatic latent image developer, wherein the storage elastic modulus (G1) of the transparent toner at 80 ° C. and the storage elastic modulus (G1) of the color toner at 80 ° C. satisfy the relationship of the following formula (1): Is a set.
1.1 ≦ G2 / G1 ≦ 3.0 (1)

The invention according to claim 5
A process cartridge comprising at least a developer holder and containing the electrostatic latent image developer set according to claim 4.

The invention according to claim 6
An image carrier, an electrostatic latent image forming unit for forming an electrostatic latent image on the image carrier, and developing the electrostatic latent image on the image carrier with a developer containing color toner and transparent toner Developing means for forming a color toner image and a transparent toner image by developing with an agent, a transfer means for transferring the color toner image and the transparent toner image onto the transfer body while superposing them, and on the transfer body Fixing means for fixing the transferred toner image,
The image forming apparatus according to claim 4, wherein the electrostatic latent image developer set according to claim 4 is used as the developer including the color toner and the developer including the transparent toner.

The invention according to claim 7 provides:
The image forming apparatus according to claim 6, wherein the fixing speed is 240 mm / s or more and 600 mm / s or less.

According to the first aspect of the present invention, there is provided a toner set capable of obtaining a stable image having high gloss, excellent color reproducibility, and no occurrence of toner blisters without impairing the strength of the fixed image.
According to the second aspect of the invention, the effect of obtaining a stable image having high gloss, excellent color reproducibility, and no occurrence of toner blisters is obtained without impairing the strength of the fixed image.
According to the third aspect of the present invention, the effect of obtaining a stable image having high gloss, excellent color reproducibility, and no toner blistering is obtained without impairing the strength of the fixed image.

According to the fourth aspect of the present invention, there is provided an electrostatic latent image developer set capable of obtaining a stable image having high gloss, excellent color reproducibility, and no occurrence of toner blisters without impairing the strength of the fixed image. Is done.
According to the fifth aspect of the present invention, there is provided a process cartridge capable of obtaining a stable image having high gloss, excellent color reproducibility, and no toner blistering without impairing the strength of the fixed image.

According to the sixth aspect of the present invention, there is provided an image forming apparatus capable of obtaining a stable image having high gloss, excellent color reproducibility, and no occurrence of toner blister without impairing the strength of a fixed image.
According to the seventh aspect of the present invention, even when an image is formed at a high speed, a stable image having high gloss, excellent color reproducibility, and no toner blister can be obtained without impairing the strength of the fixed image.

Hereinafter, this embodiment will be described in detail.
<Toner set>
The toner set of this embodiment includes one or more color toners selected from the group consisting of magenta toner, cyan toner, and yellow toner, and a transparent toner, and the storage elastic modulus (80 ° C.) of the color toner ( G1) is 10 ⁴ Pa or more and 10 ⁶ Pa or less, the tangent loss (tan δ) of the color toner at 80 ° C. is 1.0 or more and 2.5 or less, and the storage elastic modulus (G2) of the transparent toner at 80 ° C. ) And the storage elastic modulus (G1) at 80 ° C. of the color toner satisfy the relationship of the following formula (1).
1.1 ≦ G2 / G1 ≦ 3.0 (1)

  Here, the transparent toner is a toner used for a transparent toner image formed together with a color toner image. Specifically, the content of a colorant such as a dye or a pigment is approximately 0.01% by mass or less. A white toner. The transparent toner image is formed on a recording medium (transfer object) where there is no color toner image, and is formed on the color toner image where there is a color toner image.

By adopting the above-described configuration, the toner set according to the present exemplary embodiment can obtain a stable image that is highly glossy, excellent in color reproducibility, and does not generate toner blisters without impairing the strength of the fixed image.
When an image is formed on a recording medium in order to obtain a high gloss image, a layer (color toner layer) for forming a color toner image is formed on the recording medium, and the transparent layer is formed on the color toner layer. A layer for forming a toner image (transparent toner layer) is provided to increase the glossiness. In order to obtain a higher gloss image, the viscoelasticity of the color toner and the transparent toner is controlled. It turns out that there is a need.

  In addition, in order to obtain an image having high gloss and excellent color reproducibility, it is necessary to set the melt viscosity of the toner low, and further, by setting the melt viscosity of the transparent toner higher than the melt viscosity of the color toner, It has been found that image defects during fixing can be suppressed.

  Toner blister refers to the following image defects. The heating in fixing the color toner layer and the transparent toner layer on the recording medium causes expansion of air in the recording medium and evaporation of moisture. In a normal recording medium, these air and moisture pass through the gaps between the fibers. However, a part of the toner passes through the toner layer, and an image defect in which the passing portion appears as a white spot occurs. This image defect is called toner blister.

  Further, the toner also retains moisture, and when the thickness of the color toner layer and the transparent toner layer increases, the moisture in the toner also affects the toner blister. This is because when a transparent toner layer is further provided on the color toner layer and the thickness of the toner layer is increased, toner blisters are likely to occur due to the influence of moisture in the toner. This phenomenon becomes prominent when the recording medium is coated paper whose surface is coated with resin or the like.

  If the transparent toner is easier to melt than the color toner, that is, if the transparent toner is less viscoelastic and less elastic than the color toner, the transparent toner layer is formed before the color toner layer by heating when fixing the image. As a result, the transparent toner layer is melted and the transparent toner layer is covered, and then the color toner layer is melted and moisture in the toner including the color toner becomes vapor. It is considered that toner blisters are generated by breaking through the molten transparent toner layer and causing boiling.

  On the other hand, if the transparent toner is simply designed to be viscoelastically highly elastic in order to avoid the negative effects of lowering the elasticity of the transparent toner than the color toner, high gloss cannot be obtained. In addition, if the color toner is designed to be viscoelastically low in elasticity, a solid image can have high gloss and toner blistering can be suppressed, but a portion with a transparent toner layer and a portion without a transparent toner layer ( The gloss difference of only the color toner (for example, the character portion) becomes large and the uniformity of the entire gloss is lost, and the image quality is not sufficient. Here, “crystalline resin” refers to a stepwise endothermic change, that is, a DSC curve that moves away from the previous baseline and shifts to a new baseline in differential scanning calorimetry (DSC) in JIS K7121-1987. Rather, it refers to a DSC curve that has an endothermic peak away from the previous baseline and returns to the baseline again. In the case of a polymer obtained by copolymerizing other components with respect to the main chain of the crystalline resin, when the other components are 50% by mass or less, this copolymer is also called a crystalline resin.

From the above, in order to obtain an image with high gloss and excellent color reproducibility, it is possible to obtain high gloss when the color toner has a low viscoelasticity, and further, the viscoelasticity of the color toner and the viscosity of the transparent toner. The relationship of elasticity is that the viscoelasticity of the transparent toner should be higher than the viscoelasticity of the color toner, and the difference between the viscoelasticity of the transparent toner and the viscoelasticity of the color toner should not be too large. found.
Further, with this configuration, even when each of the color toner and the transparent toner contains 4% by mass or more and 20% by mass or less of a crystalline resin with respect to the entire toner, a high level of glossiness is maintained. The As a result, a high level of gloss can be obtained without impairing the strength of the fixed image.

Even if the viscoelasticity of the transparent toner is high, a high level of glossiness is maintained as long as it has a specific relationship with the viscoelasticity of the color toner (relationship of equation (1) described later).
For example, if there is a color photographic image on a part of the recording medium and there is a 100% solid part or a halftone part such as 20% in the image, the color photographic image is formed only with the color toner. In the solid portion, the glossiness can be increased by adjusting the viscoelasticity of the toner, but in the halftone portion, a high glossiness cannot be obtained due to the presence / absence of a color toner image (mixed portion of the toner image and the recording material portion). As a result, non-uniform glossiness occurs in the color photographic image.

  However, by providing a transparent toner layer in the toner set of the present embodiment on the entire color photographic image of only the above color toner, the gloss difference between the solid portion and the halftone portion is reduced, uniformity is obtained, and color photography The glossiness of the entire image can be controlled to be high.

In the toner set of this embodiment, the color toner has a storage elastic modulus (G1) at 80 ° C. of 10 ⁴ Pa to 10 ⁶ Pa, preferably 10 ^4.3 Pa to 10 ^5.5 Pa. It is more preferable that it is 10 ^4.5 Pa or more and 10 ^5.5 Pa or less. When the storage elastic modulus (G1) is less than 10 ⁴ , toner elasticity is small and high gloss can be obtained, but fixing failure such as hot offset occurs. On the other hand, if it is larger than 10 ⁶ , the elasticity of the toner is so great that fixing at low temperature becomes difficult.

  In the toner set of this embodiment, the tangent loss (tan δ) of the color toner is 1.0 or more and 2.5 or less, preferably 1.2 or more and 2.3 or less, and 1.3 or more and 2.0 or less. It is more preferable that When the tangent loss (tan δ) is less than 1.0, it is difficult to obtain high gloss, and when it is more than 2.5, fixing defects such as hot offset occur.

In the toner set of this embodiment, the storage elastic modulus (G1) of the transparent toner at 80 ° C. and the storage elastic modulus (G1) of the color toner at 80 ° C. satisfy the relationship of the following formula (1).
1.1 ≦ G2 / G1 ≦ 3.0 (1)

  (G2 / G1) in the formula (1) is preferably 1.2 or more and 2.5 or less, and more preferably 1.2 or more and 2.0 or less. When (G2 / G1) is smaller than 1.1, toner blisters are generated, and when it is larger than 2, a portion in which the gloss is lowered is generated in the transparent toner layer.

In this embodiment, the storage elastic modulus (G1), tangent loss (tan δ) of the color toner at 80 ° C., and the storage elastic modulus (G2) of the transparent toner at 80 ° C. are measured as follows.
The storage elastic modulus and tangent loss 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 amount of strain 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.

On the other hand, the toner set of this embodiment has a storage elastic modulus (G1) at 80 ° C. of the color toner of 10 ⁴ Pa to 10 ⁶ Pa, so that the crystalline resin in each of the color toner and the transparent toner can be obtained. Even when the content is 20% by mass or less, high glossiness is maintained. As a result, high glossiness is maintained without impairing the strength of the fixed image.
Further, when the content of the crystalline resin in each of the color toner and the transparent toner is 4% by mass or more, the effect that high glossiness is maintained becomes more remarkable. The content of the crystalline resin in each of the color toner and the transparent toner is more preferably 6% by mass or more and 15% by mass or less.

  Further, in the toner set of the present embodiment, the glass transition temperature of the transparent toner is higher than the glass transition temperature of the color toner, so that the storage stability of the fixed image (image transfer such as overlaying a large number of prints with the fixed image) The presence or absence of defects) is preferable.

Hereinafter, a configuration, a manufacturing method, and the like of the toner set of the present embodiment will be described.
The toner set of this embodiment includes one or more color toners selected from the group consisting of magenta toner, cyan toner, and yellow toner, and a transparent toner.
In addition, as a manufacturing method of each toner constituting the toner set of the present embodiment, a known method can be used. However, a wet manufacturing method, particularly an emulsion polymerization aggregation method is used from the viewpoint of easy preparation of a toner having a core-shell structure. It is preferable.

  The production method by the emulsion polymerization agglomeration method includes a first resin particle dispersion liquid in which first resin particles having a volume average particle diameter of 1 μm or less, and a colorant is dispersed. An aggregating step of adding a coagulant to the mixed dispersion at least mixed with the agent dispersion and heating to form core particles, and the mixed dispersion formed with the core particles from the second binder resin The second resin particle dispersion in which the second resin particles having a volume average particle diameter of 1 μm or less are dispersed is added, and the second resin particles are adhered to the surface of the core particles to adhere the resin aggregated particles. It is preferable that the process includes an adhesion process for forming the adhering resin and a fusion process for fusing the adhered resin aggregated particles.

  In the aggregation step, core particles (core aggregated particles) simply formed by aggregating various 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.

  Further, the transparent toner used in the present embodiment needs to have high elasticity with respect to the color toner. There are various methods for satisfying such a relationship of toner characteristics, but it can be adjusted by the addition amount of the flocculant in the emulsion aggregation method. A compound composed of a divalent or higher valent metal element is used as an aggregating agent, and the amount of divalent or higher valent metal added to the transparent toner is generally larger than the amount of the compound composed of a divalent or higher metal element added to the color toner. By doing so, the flocculant acts like a crosslinking component in the toner, and the viscoelasticity can be adjusted.

  On the other hand, in each toner, it is possible to adjust the viscoelasticity by changing the molecular weight of the resin to be used. In this case, however, it is possible to change the type and ratio of the monomer to avoid the Tg change accompanying the molecular weight change. As a result, a difference between the resin of the color toner and the resin of the transparent toner occurs, and the melting / adhesion between the two during fixing may be impaired. On the other hand, the adjustment of viscoelasticity by using a plurality of resins as the resin to be used and changing the blending ratio does not impair the melting / adhesion of both at the time of fixing.

  As described above, in the toner set of the present embodiment, the addition amount of the transparent toner is larger than the addition amount of the compound composed of a bivalent or higher metal element to the color toner in order to adjust the viscoelasticity of each toner. It is preferable to use for eyes, that is, the color toner and the transparent toner each contain a compound composed of a bivalent or higher metal element, and the amount of the compound composed of a bivalent or higher metal element contained in the color toner, It is preferable that the amount of the compound composed of a bivalent or higher-valent metal element contained in the transparent toner is large.

Further, the content of the compound composed of a divalent or higher valent metal element in the color toner is preferably 0.05% by mass or more and 2% by mass or less, and more preferably 0.3% by mass or more and 1.0% by mass or less.
On the other hand, the content of the compound composed of a bivalent or higher-valent metal element in the transparent toner is preferably 0.2% by mass or more and 2% by mass or less, and more preferably 0.5% by mass or more and 1.0% by mass or less.
Here, the comparison of the content of the compound composed of a divalent or higher metal element in the color toner and the transparent toner is performed by analyzing the toner with all elements by fluorescent X-rays, and the total intensity of the detected divalent or higher metal element is calculated. It is obtained by comparing. The content can be obtained by preparing a calibration curve of the intensity with respect to the content using the used compound and comparing the detected intensity with it.

  Full-color copiers and printers that have become widespread in recent years require a device for supplying an offset prevention liquid to the heat fixing roll or fixing belt in order to prevent contamination by toner components and offset in the fixing process. There's a problem. This is in the opposite direction to the reduction in size and weight, and the anti-offset liquid may be heated and evaporated to give an unpleasant odor or cause in-flight contamination. Therefore, in order to obtain good fixability in the absence of the offset prevention liquid, it is preferable that each toner used in the exemplary embodiment includes a wax as a release agent.

The release agent (wax) is selected from the viewpoints of fixing properties, toner blocking properties, toner strength, and the like.
Examples of the wax include paraffin wax and derivatives thereof, montan wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax and derivatives thereof, and the like. Here, the derivatives include oxides, polymers with vinyl monomers, and graft modified products. Alcohols, fatty acids, plant waxes, animal waxes, mineral waxes, ester waxes, acid amides and the like can also be used.

  The wax has a melting point of 70 ° C. or more and 140 ° C. or less, preferably exhibits a melt viscosity of 1 centipoise or more and 200 centipoise or less (150 ° C.), and more preferably exhibits a melt viscosity of 1 centipoise or more and 100 centipoise or less. . If the melting point is less than 70 ° C., the change temperature of the wax is too low, the blocking resistance may be inferior, and the developability may deteriorate when the temperature in the copying machine increases. On the other hand, when the temperature exceeds 140 ° C., the changing temperature of the wax may increase. Further, when the melt viscosity is higher than 200 centipoise, the elution from the toner is weak, and the fixing peelability may be insufficient.

The amount of wax added to each toner is preferably 1% by mass or more and 15% by mass or less, and more preferably 3% by mass or more and 10% by mass or less. If the added amount of wax is less than 1% by mass, a sufficient fixing latitude (fixing roll or fixing belt temperature range capable of fixing without toner offset) may not be selected. In some cases, the amount of the wax released away increases and contamination of the developer holder tends to occur. In addition, the powder fluidity of the toner may deteriorate, and free wax may adhere to the surface of the photoconductor that forms an electrostatic latent image, making it impossible to form the electrostatic latent image accurately. In addition, since the wax is inferior in transparency as compared with the binder resin, the transparency of the image such as OHP may be reduced, and a projected image may be formed.
The amount of wax added to each toner is preferably in the range of 2 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin contained in the toner.

As the color toner in this embodiment, a known toner containing at least a colorant and a binder resin is used. Hereinafter, preferred embodiments of the color toner will be described.
Examples of binder resins used in color toners include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene, and isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl acetate. A-methylene aliphatic monocarboxylic acid ester such as methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Examples include homopolymers or copolymers of vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone, etc. Particularly typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene. -Maleic anhydride copolymer, polyethylene, polypropylene can be mentioned. Further examples include polyester, polyurethane, epoxy resin, silicon resin, polyamide, modified rosin, paraffin, and waxes. Among these, it is particularly preferable to use polyester as a binder resin.

The polyester resin used in this embodiment is synthesized from a polyol component and a polycarboxylic acid component by polycondensation. In the present embodiment, 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 are also included, but not limited thereto.

Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and the like, and anhydrides thereof. And lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.
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.

On the other hand, as the polyhydric alcohol component, as the divalent polyhydric alcohol, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2 , 2-bis (4-hydroxyphenyl) propane and other bisphenol A alkylene (2 to 4 carbon) oxide adducts (average addition mole number 1.5 to 6), ethylene glycol, propylene glycol, neopentyl glycol, 1 , 4-butanediol, 1,3-butanediol, 1,6-hexanediol and the like.
Examples of the trihydric or higher polyhydric alcohol include sorbitol, pentaerythritol, glycerol, trimethylolpropane and the like.

  In the amorphous polyester resin, among the raw material monomers described above, a dihydric or higher secondary alcohol and / or a divalent or higher aromatic carboxylic acid compound are preferable. Examples of the dihydric or higher secondary alcohol include propylene oxide adducts of bisphenol A, propylene glycol, 1,3-butanediol, glycerol and the like. Among these, propylene oxide adducts of bisphenol A are preferable and divalent. As the above aromatic carboxylic acid compound, terephthalic acid, isophthalic acid, phthalic acid and trimellitic acid are preferable, and terephthalic acid and trimellitic acid are more preferable.

  The softening point is 90 ° C. or more and 150 ° C. or less, the glass transition temperature is 55 ° C. or more and 75 ° C. or less, the number average molecular weight is 2000 or more and 10,000 or less, the weight average molecular weight is 8000 or more and 150,000 or less, the acid value is 5 or more and 30 or less, A resin having a value of 5 or more and 40 or less can be particularly preferably used.

Further, it is preferable to use a crystalline polyester resin as a part of the binder resin in order to impart low-temperature fixability to the toner.
The crystalline polyester resin is preferably composed of an aliphatic dicarboxylic acid and an aliphatic diol, and more preferably a linear dicarboxylic acid or a linear aliphatic diol having a main chain portion having 4 to 20 carbon atoms. In the branched type, 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, if the number of carbon atoms is less than 4, the ester bond group concentration is high, so that the electrical resistance is low, and the influence thereof adversely affects the toner chargeability. . The carbon number is more preferably 14 or less.

  Examples of the aliphatic dicarboxylic acid suitably used for the synthesis of the crystalline polyester include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelinic acid, sebacic acid, 1,9-nonane. Dicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid Examples include acids, 1,18-octadecanedicarboxylic acid, and the like, or lower alkyl esters and acid anhydrides thereof. Among these, considering availability, sebacic acid and 1,10-decanedicarboxylic acid are preferable.

  Specific examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 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 the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like. These may be used individually by 1 type and may use 2 or more types together.

  Among the polyvalent carboxylic acid components, the content of the aliphatic dicarboxylic acid is preferably 80 mol% or more, and more preferably 90% or more. When the content of the aliphatic dicarboxylic acid 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. . Among the polyhydric alcohol components, the content of the aliphatic diol component is preferably 80 mol% or more, and more preferably 90% 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 benzyl alcohol can also be used for the purpose of adjusting the acid value and hydroxyl value.

The production method of the polyester resin is not particularly limited, and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. Examples thereof include direct polycondensation and transesterification. Depending on the type, it will be manufactured separately.
The polyester resin can be produced by subjecting the polyhydric alcohol and polyhydric carboxylic acid to a condensation reaction according to a conventional method. For example, the above polyhydric alcohol and polyvalent carboxylic acid, if necessary, a catalyst, and blended in a reaction vessel equipped with a thermometer, a stirrer, a flow-down condenser, and in the presence of an inert gas (such as nitrogen gas), Heat at 150 to 250 ° C. to continuously remove by-product low-molecular compounds out of the reaction system, stop the reaction when a predetermined acid value is reached, cool, and obtain the desired reactant Can be manufactured.

  In this embodiment, the colorant is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP permeability, and dispersibility in the toner. Examples of the colorant include carbon black, nigrosine, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, C. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 238, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 180, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 can be exemplified as a representative example.

  The amount of the colorant added to the color toner of this embodiment is preferably in the range of 4 to 20 parts by mass with respect to 100 parts by mass of the binder resin contained in the toner.

  The color toner according to the exemplary embodiment may include one or more charge control agents that adjust charge as an internal additive in addition to the above components. In addition, a petroleum resin may be included in order to satisfy the pulverization property and heat storage property of the toner. Petroleum-based resins are synthesized from diolefins and monoolefins contained in cracked oil fractions by-produced from an ethylene plant that produces ethylene, propylene and the like by steam cracking of petroleum.

  Although the color toner in the present embodiment has been described above, the transparent toner in the present embodiment includes those containing the same components as the color toner in the present embodiment except that the color toner is not included.

The color toner and the transparent toner (hereinafter sometimes referred to as “each toner according to the present embodiment”) constituting the toner set according to the present embodiment include a dry process such as kneading and pulverization, a suspension weight, and the like. Examples thereof include wet methods such as a combination method and an emulsion aggregation method. Among these, by selecting the heating temperature condition, the toner shape can be arbitrarily controlled from an indeterminate shape to a spherical shape, and an emulsion aggregation method that is advantageous in precisely controlling the toner shape is preferable.
In the emulsion aggregation method, a resin dispersion is prepared by emulsion polymerization or emulsification. On the other hand, a colorant dispersion in which a colorant is dispersed in a solvent and a dispersion in which a release agent is dispersed are prepared and mixed. In this method, aggregated particles corresponding to the toner particle diameter are formed and then fused to form toner particles by heating.

Next, a method for producing a toner by an emulsion aggregation method suitable for producing each toner of this embodiment will be described in more detail.
The toner production method by the emulsion aggregation method is a method including an aggregation step, an adhesion step, and a fusion step. Hereinafter, it demonstrates in detail for every 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 a flocculant and heating at a temperature slightly lower than the melting point of the first binder resin, agglomerated particles (core agglomerated particles) are formed by aggregating particles composed of the respective components. The fused particles (core fused particles) may be formed by heating at a temperature equal to or higher than the glass transition temperature of the first binder resin and performing fusion at the same time as 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 compound having a divalent or higher valent metal element can be suitably used in addition to a surfactant having a reverse polarity to the surfactant used as a dispersing agent for various dispersions. In the present embodiment, the tangent loss (tan δ) and the storage elastic modulus (G1) can be controlled by the amount of the metal complex having a valence of 2 or more. Increasing the amount of use reduces the tangent loss and reduces the storage elastic modulus. It tends to increase. In addition, 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 compound composed of a metal element include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, calcium polysulfide, etc. And 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, the resin 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 surface are referred to as “adhesive resin agglomerated particles”). Here, this coating layer corresponds to the shell layer of the toner of the present embodiment formed through a fusion process described later.
The coating layer can be formed by additionally adding the second resin particle dispersion into the dispersion in which the core particles are formed in the aggregation step, and if necessary, other components can be added at the same time. Also good.

  When the adhered resin aggregated particles are uniformly adhered to the surface of the core particles to form a coating layer, and the adhered resin aggregated particles are heat-fused in a fusion step described later, The resin particles made of the binder resin 2 are melted to form a shell layer. For this reason, it is possible to effectively prevent components such as a 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 the method of addition mixing of the 2nd resin particle dispersion liquid in an adhesion process, For example, you may carry out gradually continuously and may carry out in steps divided into several times. In this way, by adding and mixing the second resin particle dispersion, it is possible to suppress the generation of fine particles and sharpen the particle size distribution of the toner obtained.
In the present embodiment, the number of times that 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 particle dispersion but also a plurality of 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 particles made of the second binder resin to the core particles are as follows. That is, the heating temperature in the adhesion 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 a 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 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 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 exceeding 10 ° C. higher than the melting point of the first binder resin, the resin particles composed of the first binder resin existing on the surface of the core particles and the second particles attached to the surface of the core particles. It becomes easy to adhere to resin particles made of a resin.
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 attaching 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 particle dispersion to the mixed dispersion in which the core particles are formed may be left standing or 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 higher temperature or higher of the glass transition temperatures 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 unconditionally, but is generally 30 minutes to 10 hours.

When the core particles are core fusion particles, resin 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 particle dispersion is added. Thereby, the particle | grains which consist of 2nd binder resin are made to adhere to the surface of a core fusion particle.
When the water content of the dispersion is lower than 30% by mass, the adhesion of the particles made of the second binder resin is poor, and the 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 particles made of the second binder resin may not adhere uniformly to the surface of the core fused particles.

  In addition, mechanical stress by a Henschel mixer or the like is applied to the adhered resin agglomerated particles obtained by adhering the particles made of the second binder resin to the surface of the core fused particles after the washing / drying process described below. Thus, the 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 preferably have a moisture content after drying of preferably 1.0% by mass or less, more preferably 0.5% by mass or less.

Next, a method for preparing a binder resin dispersion, a colorant dispersion, and a release agent dispersion used in the aggregation process will be described.
A known emulsification method can be used to prepare the binder resin dispersion, but the obtained particle size distribution is sharp and the volume average particle size is easily obtained in the range of 0.08 to 0.40 nm. A phase inversion emulsification method is effective.
In the phase inversion emulsification method, the resin is dissolved in an organic solvent for dissolving the resin, an amphiphilic organic solvent alone, or a mixed solvent to obtain an oil phase. A small amount of a basic compound is dropped while stirring the oil phase, and water is dropped little by little while stirring, and water droplets are taken into the oil phase. Next, when the dripping amount of water exceeds a certain amount, the oil phase and the water phase are reversed and the oil phase becomes oil droplets. Thereafter, an aqueous dispersion is obtained through a desolvation step of depressurization.

  Here, the amphiphilic organic solvent means a solvent having a solubility in water at 20 ° C. of at least 5 g / L or more, preferably 10 g / L or more. When the solubility is less than 5 g / L, there is a problem that the effect of accelerating the aqueous treatment speed is poor, and the resulting aqueous dispersion is also inferior in storage stability. Examples of such organic solvents that can be used include ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert- Alcohols such as amyl alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, cyclohexanol, ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclohexanone, isophorone, tetrahydrofuran, Ethers such as dioxane, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, acetic acid-sec-butyl, acetic acid-3-methoxybutyl, propio Esters such as methyl acid, ethyl propionate, diethyl carbonate, dimethyl carbonate, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, diethylene glycol, Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol ethyl ether acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, Glycol derivatives such as propylene glycol methyl ether acetate and dipropylene glycol monobutyl ether, as well as 3-methoxy-3-methylbutanol, 3-methoxybutanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate, etc. It can be illustrated. These solvents can be used singly or in combination of two or more.

  Next, regarding the basic compound, the polyester resin used in this embodiment is neutralized with the basic compound when dispersed in an aqueous medium. In this embodiment, the neutralization reaction with the carboxyl group of the polyester resin is the starting force for aqueous formation, and aggregation between particles can be prevented by the electric repulsion between the generated carboxyl anions. Examples of the basic compound include ammonia and organic amine compounds having a boiling point of 250 ° C. or lower. Examples of preferred organic amine compounds include triethylamine, N, N-diethylethanolamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine , Diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, Triethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine and the like can be mentioned. The basic compound is preferably added in an amount that can be at least partially neutralized according to the carboxyl group contained in the polyester resin, that is, 0.2 to 9.0 times equivalent to the carboxyl group. It is more preferable to add 6 to 2.0 times equivalent. If the amount is less than 0.2 times equivalent, the effect of adding a basic compound is not observed. If the amount exceeds 9.0 times equivalent, it seems that the hydrophilicity of the oil phase increases excessively, but the particle size distribution becomes broad and good. A stable dispersion cannot be obtained.

  The colorant dispersion is formed by dispersing at least a colorant. The colorant is dispersed by a known method. For example, a rotary-type homogenizer, a ball-type mill, a sand mill, an attritor-type media type dispersing machine, a high-pressure counter-collision type dispersing machine, or the like is preferably used. The colorant is an ionic surfactant having polarity and can be dispersed in an aqueous solvent using a homogenizer as described above to prepare a colorant particle dispersion. A coloring agent may be used individually by 1 type, and may use 2 or more types together. The volume average particle size of the colorant (hereinafter sometimes simply referred to as the average particle size) is usually 1.0 μm (that is, 1 μm or less) at most, but is 0.5 μm (that is, 0.5 μm or less) at most. Is preferable, and 0.01 to 0.5 μm is particularly preferable.

  The release agent dispersion is formed by dispersing at least a release agent. The release agent is dispersed by a known method, and for example, a rotary shearing type homogenizer, a media type dispersing machine such as a ball mill, a sand mill, or an attritor, a high pressure opposed collision type dispersing machine or the like is preferably used. In addition, the release agent may be a ionic surfactant having polarity and dispersed in an aqueous solvent using a homogenizer as described above to prepare a release agent particle dispersion. In this embodiment, a mold release agent may be used individually by 1 type, and may be used in combination of 2 or more types. The average particle size of the release agent particles is preferably at most 1 μm (that is, 1 μm or less), more preferably from 0.01 to 1 μm.

There is no restriction | limiting in particular as a combination of resin of the said resin particle, the said coloring agent, and the said mold release agent, According to the objective, it can select and use suitably suitably.
In the present embodiment, depending on the purpose, at least one of the binder resin dispersion, the colorant dispersion, and the release agent dispersion includes an internal additive, a charge control agent, inorganic particles, and organic particles. It is possible to disperse other components (particles) such as bodies, lubricants, and abrasives. In that case, other components (particles) may be dispersed in at least one of the binder resin dispersion, the colorant dispersion, and the former agent dispersion, or the resin particle dispersion and the recording agent. You may mix the dispersion liquid which disperse | distributes another component (particle | grains) in the liquid mixture formed by mixing a dispersion liquid and a mold release agent dispersion liquid.

  Examples of the dispersion medium in the binder resin dispersion, the colorant dispersion, the release agent dispersion, and the other components include an aqueous medium. Examples of the aqueous medium include water such as distilled water and ion exchange water, alcohol, and the like. These may be used individually by 1 type and may use 2 or more types together. As a suitable combination, distilled water and ion exchange water are preferably used. That's right. The addition of a surfactant is not only advantageous in terms of the stability of each dispersed particle, such as resin particles, colorant particles, and release agent particles, in the aqueous medium, and thus the storage stability of the dispersion, but also in the aggregation process. This is also advantageous from the viewpoint of the stability of the aggregated particles.

In addition, rosin, rosin derivatives, coupling agents, polymer dispersions are added as dispersants to further stabilize the dispersion stability of the colorant in the aqueous medium and lower the energy of the colorant in the toner. Agents and the like.
In the present embodiment, it is preferable to add and mix a surfactant in an aqueous medium in order to improve dispersion stability.

  The volume average particle size of the particle dispersion thus obtained can be measured, for example, with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). As a measuring method, the sample in the state of dispersion is adjusted to 2 g in solid content, and ion exchange water is added thereto to make 40 ml. This is put into the cell until an appropriate concentration is reached, and after 2 minutes, the concentration is measured when the concentration in the cell becomes stable. The volume-volume average particle diameter for each obtained channel was accumulated from the smaller volume-volume average particle diameter, and the place where the accumulation reached 50% was defined as the volume-average particle diameter.

  The volume average particle size of each toner in the exemplary embodiment is preferably 3 μm or more and 9 μm or less, and more preferably 3 μm or more and 8 μm or less. If the particle size is less than 3 μm, the chargeability may be insufficient and the developability may deteriorate, and if it exceeds 9 μm, the resolution of the image may decrease.

Each toner in the present embodiment preferably has a volume average particle size distribution index GSDv of 1.30 or less.
When the volume distribution index GSDv exceeds 1.30, the resolution of the image may deteriorate.
In this embodiment, the toner particle size and the value of the volume average particle size distribution index GSDv are measured and calculated as follows. First, individual particle size distributions (channels) of the toner particle size distribution measured using a measuring instrument such as Coulter Counter TAII (manufactured by Nikka Machine Co., Ltd.), Multisizer II (manufactured by Nikka Kisha Co., Ltd.) A cumulative distribution is drawn from the small diameter side with respect to the volume of the toner particles, and the particle diameter of 16% is defined as the volume average particle diameter D16v, and the particle diameter of 50% is defined as the volume average particle diameter D50v. Similarly, the particle diameter that is 84% cumulative is defined as the volume average particle diameter D84v. At this time, the volume average particle size distribution index (GSDv) can be calculated using these relational expressions defined as D84v / D16v.

Each toner in the present embodiment preferably has a shape factor SF1 (= ((absolute maximum length of toner diameter) ² / toner projection area) × (π / 4) × 100) in a range of 110 to 160. . The shape factor SF1 is more preferably in the range of 125 to 140.
Note that the value of the shape factor SF1 indicates the roundness of the toner, which is 100 in the case of a true sphere, and increases as the shape of the toner becomes indefinite. Further, values necessary for calculation using the shape factor SF1, that is, the absolute maximum length of the toner diameter and the projected area of the toner are toner particles enlarged by a magnification of 500 times using an optical microscope (Nikon, Microphoto-FXA). An image was taken, and the obtained image information was introduced into, for example, an image analysis apparatus (Luxex III) manufactured by Nicole via an interface, and image analysis was performed to obtain the image information. The average value of the shape factor SF1 was calculated based on data obtained by measuring 1000 toner particles sampled randomly.

  When the shape factor SF1 is less than 110, generally, residual toner is generated in the transfer process during image formation. Therefore, it is necessary to remove the residual toner. However, the cleaning performance when the residual toner is cleaned with a blade or the like is required. It is easy to damage and may result in image defects. On the other hand, when the shape factor SF1 exceeds 160, when the toner is used as a developer, the toner may be destroyed due to a collision with a carrier in the developing device. In this case, as a result, the fine powder increases or the release agent component exposed on the toner surface may contaminate the surface of the photoreceptor and impair the charging characteristics. May cause problems.

Also, for the purpose of imparting fluidity and improving cleaning properties, after drying, inorganic particles such as silica, alumina, titania and calcium carbonate, inorganic oxide particles, resins such as vinyl resins, polyesters and silicones are dried. The particles can be added to the toner surface according to the exemplary embodiment as a fluidity aid or a cleaning aid by shearing in a dry state.
Examples of inorganic oxide particles added to the toner include SiO ₂ , TiO ₂ , Al ₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, CaO, K ₂ O, Na ₂ O, be exemplified _{ZrO 2, CaO · SiO 2,} K2O · (TiO 2) n (n = 1~6 _{integer), Al 2 O 3 · 2SiO} 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 , etc. it can. Of these, silica particles and titania particles are particularly preferable. It is preferable that the surface of the inorganic oxide particles is previously hydrophobized. This hydrophobization treatment is more effective for improving the powder fluidity of the toner, as well as the environmental dependency of charging and the resistance to carrier contamination.

  The hydrophobizing treatment can be performed by immersing the inorganic oxide particles in a hydrophobizing agent. Although there is no restriction | limiting in particular as said hydrophobic treatment agent, For example, a silane coupling agent, a silicone oil, a titanate coupling agent, an aluminum coupling agent etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, silane coupling agents are preferable.

  As the silane coupling agent, for example, any one of chlorosilane, alkoxysilane, silazane, and a special silylating agent can be used. Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, Methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltriethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N- ( Trimethylsilyl) urea, tert-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane , Γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercapto Examples thereof include propyltrimethoxysilane and γ-chloropropyltrimethoxysilane. The amount of the hydrophobizing agent varies depending on the type of the inorganic oxide particles and cannot be defined unconditionally, but is usually 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the inorganic oxide particles. preferable.

<Electrostatic latent image developer set>
The electrostatic latent image developer set of the present embodiment (hereinafter sometimes referred to as “developer set of the present embodiment”) is an electrostatic latent image developer (including the color toner used in the present embodiment described above). Developer) and a developer containing transparent toner.
Each developer constituting the developer set of this embodiment may be either a one-component system or a two-component system including a carrier, but is preferably a two-component system.

  The carrier used in the present embodiment is not particularly defined, but examples of the carrier core material include magnetic metals such as iron, steel, nickel, and cobalt, alloys of these with manganese, chromium, rare earth, ferrite, magnetite, and the like. From the viewpoint of core surface properties and core resistance, ferrites, particularly alloys with manganese, lithium, strontium, magnesium and the like are preferable.

  The carrier used in the present embodiment is preferably formed by coating a resin on the surface of the core material, and the resin is not particularly limited and can be appropriately selected depending on the purpose. For example, polyolefin resins such as polyethylene and polypropylene; polyvinyl resins and polyvinylidene resins such as polystyrene, acrylic resins, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and polyvinyl ketone Vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; straight silicone resin composed of organosiloxane bond or modified product thereof; polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc. Fluorine resin; Silicone resin; Polyester resin; Polyurethane resin; Polycarbonate resin; Phenol resin; Urea-formaldehyde resin Melamine resins, benzoguanamine resins, urea resins, amino resins such as polyamide resins, epoxy resins, per se known resins and the like. These may be used individually by 1 type and may use 2 or more types together.

  In the present embodiment, among the above resins, it is preferable to use at least a fluorine resin or a silicone resin. The use of at least a fluorine-based resin or a silicone resin as the resin is advantageous in that it has a high effect of preventing carrier contamination (impact) due to toner and external additives.

In the resin coating, resin particles and / or conductive (volume resistivity at 20 ° C .: 10 ² Ωcm or less) particles are preferably dispersed in the resin. Examples of the resin particles include thermoplastic resin particles and thermosetting resin particles. Among these, thermosetting resins are preferable from the viewpoint of relatively easily increasing the hardness, and resin particles made of nitrogen-containing resin containing N atoms are preferable from the viewpoint of imparting negative chargeability to the toner. In addition, these resin particles may be used individually by 1 type, and may use 2 or more types together.

  The average particle diameter of the resin particles is preferably 0.1 μm or more and 2 μm or less, more preferably 0.2 μm or more and 1 μm or less. When the average particle size of the resin particles is less than 0.1 μm, the dispersibility of the resin particles in the coating may be deteriorated. On the other hand, if it exceeds 2 μm, the resin particles are likely to fall off from the coating, and the original effect may not be exhibited.

  Examples of the conductive particles include metal particles such as gold, silver, and copper, carbon black particles, and surfaces of titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate powder, tin oxide, carbon black, metal And particles covered with the like. These may be used individually by 1 type and may use 2 or more types together. Among these, carbon black particles are preferable from the viewpoints of production stability, cost, conductivity, and the like. The type of carbon black is not particularly limited, but carbon black having a DBP oil absorption of 50 ml / 100 g or more and 250 ml / 100 g or less is preferable because of excellent production stability. The coating amount of the resin, the resin particles, and the conductive particles on the core material surface is preferably 0.5% by mass or more and 5.0% by mass or less, and 0.7% by mass or more and 3.0% by mass or less. More preferred.

  Moreover, it is preferable that the electroconductive particle contained in the said film is a white electroconductive particle at the point which the color of the image obtained becomes favorable. This is because even if the coating is peeled off, the color of the image is not affected. This effect becomes prominent when the carrier used in combination with the transparent toner is a film containing white conductive particles. Examples of the white conductive particles include particles in which the surface of titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate powder or the like is covered with tin oxide, and titanium oxide, zinc oxide, barium sulfate powder The particles having the surface covered with tin oxide are preferred.

  The method for forming the coating is not particularly limited. For example, the resin particles such as crosslinkable resin particles and / or the conductive particles, and a styrene acrylic resin, a fluorine resin, a silicone resin as a matrix resin, etc. And a method of using a film-forming solution containing the above resin in a solvent. Specifically, the carrier core material is immersed in the film forming liquid, a spray method in which the film forming liquid is sprayed on the surface of the carrier core material, and the carrier core material is floated by flowing air And kneader coater method in which the film forming solution is mixed and the solvent is removed. Among these, the kneader coater method is preferable.

  The solvent used in the film-forming liquid is not particularly limited as long as it can dissolve only the resin as a matrix resin, and can be selected from among solvents known per se, for example, Aromatic hydrocarbons such as toluene and xylene, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran and dioxane, and the like. When the resin particles are dispersed in the coating, since the resin particles and the particles as the matrix resin are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface, the carrier is used for a long time. Even when the coating is worn, it is possible to always maintain the same surface formation as when it is not used, and to maintain a good charge imparting ability for the toner over a long period of time. In the case where the conductive particles are dispersed in the coating, the conductive particles and the resin as the matrix resin are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface. Even when the coating is worn out for a long period of time, the same surface formation as when not in use can be maintained, and carrier deterioration can be prevented for a long period of time. In addition, when the said resin particle and the said electroconductive particle are disperse | distributed to the said film, there can exist the above-mentioned effect simultaneously.

The electrical resistance (volume resistivity) of the entire carrier formed as described above in the state of a magnetic brush under an electric field of 10 ⁴ V / cm is preferably 10 ⁸ to 10 ¹³ Ωcm. If the electric resistance of the magnetic carrier is less than 10 ⁸ Ωcm, the carrier may adhere to the image portion on the latent image holding member and a brush mark may be easily generated. On the other hand, when the electric resistance of the magnetic carrier exceeds 1 × 10 ¹³ Ωcm, an edge effect can be seen and image quality may be deteriorated.

The volume resistivity is measured as follows.
Under conditions of 22 ° C. and humidity of 55%. A measuring jig that is a pair of 20 cm ² circular electrode plates (made of steel) connected to an electrometer (manufactured by KEITHLEY, trade name: KEITHLEY 610C) and a high-voltage power supply (trade name: FLUKE 415B). The sample is placed on the lower electrode plate to form a flat layer having a thickness of about 1 mm to 3 mm. Next, after the upper electrode plate is placed on the sample, a 4 kg weight is placed on the upper electrode plate in order to eliminate the gap between the samples. In this state, the thickness of the sample layer is measured. Next, the current value is measured by applying a voltage to the bipolar plate, and the volume resistivity is calculated based on the following equation.
Volume resistivity = applied voltage × 20 ÷ (current value−initial current value) ÷ sample thickness In the above formula, the initial current is the current value when the applied voltage is 0, and the current value indicates the measured current value.

<Process cartridge and image forming apparatus>
The image forming apparatus according to the present embodiment includes an image holding member, an electrostatic latent image forming unit that forms an electrostatic latent image on the image holding member, an electrostatic latent image on the image holding member, and color toner. Developing means for developing a color toner image and a transparent toner image by developing with a developer containing the developer and a transparent toner, and a transfer for transferring the color toner image and the transparent toner image onto the transfer medium while superimposing the color toner image and the transparent toner image And an electrostatic latent image of the present embodiment as a developer containing the color toner and a developer containing the transparent toner, and a fixing means for fixing the toner image transferred onto the transfer medium. As long as the developer set is used, the configuration is not limited to the following.
In addition, the process cartridge according to the present embodiment includes at least a developer holder, and accommodates the electrostatic latent image developer set according to the present embodiment.

Here, the transfer unit is a unit that forms a full color image by superimposing a color toner image and a transparent toner image of yellow, magenta, cyan, and black, which are usually formed by color separation. In the form, not only a full-color image but also a case where a color toner image of one color, two colors, and three colors and a transparent toner image are transferred onto a recording medium while being superimposed are included.
As the transfer means, for example, an intermediate transfer member may be provided between the image carrier and the recording medium.

The intermediate transfer member includes a primary transfer unit that transfers the toner image formed on the image holding member onto the intermediate transfer member, and a secondary transfer unit that transfers the toner image on the intermediate transfer member onto a recording medium. In the image forming apparatus, an image forming apparatus including an intermediate transfer belt as a secondary transfer unit is preferable because a high-quality transfer image quality can be obtained.
In addition, the image forming apparatus having the above-described configuration is, for example, a normal monocolor image forming apparatus that stores a single color toner in a developing device, or a toner image held on an image holding member such as a photosensitive drum, as an intermediate transfer. A color image forming apparatus in which primary transfer is sequentially performed on a body, a tandem color image forming apparatus in which a plurality of image holding bodies each having a developing device for each color are arranged in series on an intermediate transfer body may be used.

  FIG. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present exemplary embodiment. The image forming apparatus according to the present embodiment has a tandem configuration in which a plurality of photoconductors as image holding members, that is, a plurality of image forming units (image forming units) are provided.

  As shown in FIG. 1, the image forming apparatus according to this embodiment forms a transparent image with four image forming units 50Y, 50M, 50C, and 50K that respectively form yellow, magenta, cyan, and black images. The image forming units 50T to be arranged are arranged in parallel (tandem) at a predetermined interval. Here, the image forming units 50Y, 50M, 50C, 50K, and 50T are basically configured in the same manner except for the color of the toner in the stored developer. This will be explained as a representative.

  The yellow image forming unit 50Y includes a photoconductor 11Y as an image carrier, and the photoconductor 11Y is driven to rotate at a predetermined process speed by a driving unit (not shown) along the direction of an arrow A shown in the drawing. It has become. As the photoreceptor 11Y, for example, an organic photoreceptor having sensitivity in the infrared region is used.

  In the image forming apparatus of the present embodiment, the fixing speed is preferably in the range of 240 mm / s or more and 600 mm / s or less, and more preferably 300 mm / s or more and 500 mm / s or less. The image forming apparatus according to the present exemplary embodiment has high gloss, excellent color reproducibility, and no toner blistering without damaging the strength of the fixed image even when the fixing speed is 240 mm / s or more and 600 mm / s or less. The effect that a stable image is obtained is obtained. Here, the fixing speed is a speed at which the recording material travels in the fixing device.

  A charging roll (charging means) 18Y is provided above the photoconductor 11Y. A predetermined voltage is applied to the charging roll 18Y by a power source (not shown) to charge the surface of the photoconductor 11Y to a predetermined potential. (This also applies to the charging rolls 18M, 18C, 18K and the photoconductors 11M, 11C, 11K).

  Around the photoreceptor 11Y, an exposure device (electrostatic latent image) that forms an electrostatic latent image by performing image exposure on the surface of the photoreceptor 11Y downstream of the charging roll 18Y in the rotation direction of the photoreceptor 11Y. (Forming means) 19Y is arranged. Here, as the exposure device 19Y, an LED array that can be miniaturized is used because of space, but the present invention is not limited to this, and other latent image forming means using a laser beam or the like may be used. Of course there is no problem.

  Further, a yellow developing device (developing means) 20Y is disposed around the photoconductor 11Y on the downstream side in the rotation direction of the photoconductor 11Y with respect to the exposure device 19Y, and is formed on the surface of the photoconductor 11Y. The electrostatic latent image is visualized with yellow toner, and a toner image is formed on the surface of the photoreceptor 11Y.

  Below the photoconductor 11Y, an intermediate transfer belt (primary transfer means) 33 for primary transfer of a toner image formed on the surface of the photoconductor 11Y extends below the five photoconductors 11T, 11Y, 11M, 11C, and 11K. The intermediate transfer belt 33 is pressed against the surface of the photoreceptor 11Y by the primary transfer roll 17Y. Further, the intermediate transfer belt 33 is stretched by three rolls of a drive roll 12, a support roll 13, and a bias roll 14, and is rotated in the direction of arrow B at a moving speed equal to the process speed of the photoconductor 11Y. It has become. On the surface of the intermediate transfer belt 33, the transparent toner image is primarily transferred prior to the yellow toner image primarily transferred as described above, and then the yellow toner image primarily transferred as described above is primarily transferred. The toner images of magenta, cyan, and black are sequentially primary transferred and stacked one after another.

  Further, around the photoreceptor 11Y, the toner remaining on the surface of the photoreceptor 11Y and the retransferred toner are cleaned downstream of the primary transfer roll 17Y in the rotation direction (arrow A direction) of the photoreceptor 11Y. A cleaning device 15Y is arranged, and a cleaning blade in the cleaning device 15Y is attached so as to be in pressure contact with the surface of the photoreceptor 11Y in the counter direction.

  A secondary transfer roll (secondary transfer means) 34 is pressed against the bias roll 14 that stretches the intermediate transfer belt 33 via the intermediate transfer belt 33, and is primarily transferred and laminated on the surface of the intermediate transfer belt 33. The toner image is electrostatically transferred onto the surface of the recording paper (transfer target) fed from a paper cassette (not shown) to the pressure contact portion between the bias roll 14 and the secondary transfer roll 34. . At this time, since the toner image transferred and laminated on the intermediate transfer belt 33 has the transparent toner image at the bottom (position in contact with the intermediate transfer belt 33), in the toner image transferred on the surface of the recording paper, The transparent toner image is on top.

  Also, below the support roll 13 of the intermediate transfer belt 33, a fixing device (fixing means) for transferring the toner image transferred onto the recording paper onto the recording paper surface by heat and pressure to form a permanent image. 35 is arranged.

  The fixing device used in this embodiment includes, for example, a fluororesin component on the surface, a low surface energy material typified by silicone resin, and a belt having a belt shape, and similarly a fluororesin component on the surface. Examples thereof include those using a low surface energy material typified by a silicone-based resin and having a cylindrical roll shape.

  Next, the operation of each of the image forming units 50Y, 50M, 50C, and 50K that forms images of each color of yellow, magenta, cyan, and black configured as described above will be described. Since the operations of the image forming units 50Y, 50M, 50C, and 50K are the same, the operation of the yellow image forming unit 50Y will be described as a representative example here.

  In the yellow developing unit 50Y, the photoconductor 11Y rotates in the direction of arrow A at a predetermined process speed, and the surface of the photoconductor 11Y is applied with a predetermined voltage to the charging roll 18Y by a power source (not shown). Then, it is negatively charged to a predetermined potential by a discharge generated in a minute gap between the charging roll 18Y and the photoreceptor 11Y or by injection of electric charges. Thereafter, image exposure is performed by the exposure device 19Y on the surface of the photoreceptor 11Y, and an electrostatic latent image corresponding to the image information is formed. Subsequently, the electrostatic latent image formed on the surface of the photoreceptor 11Y is reversely developed with the negatively charged toner by the developing device 20Y, and is visualized on the surface of the photoreceptor 11Y to form a toner image. Thereafter, the toner image on the surface of the photoreceptor 11Y is primarily transferred onto the surface of the intermediate transfer belt 33 by the primary transfer roll 17Y. After the primary transfer, the toner 11Y remaining on the surface of the photoreceptor 11Y is scraped off and cleaned by the cleaning blade of the cleaning device 15Y to prepare for the next image forming process.

  The above operations are performed by the image forming units 50T, 50Y, 50M, 50C, and 50K, and the toner images visualized on the surfaces of the photoreceptors 11T, 11Y, 11M, 11C, and 11K are successively transferred to the intermediate transfer belt. 33 is transferred onto the surface. In the full color mode, the toner images of each color are transferred in the order of transparent, yellow, magenta, cyan, and black. In the two-color and three-color modes, only the toner images of the necessary colors are used in this order. Or, multiple transfer is performed. Thereafter, the toner image which is individually or multiply transferred onto the surface of the intermediate transfer belt 33 is secondarily transferred onto the surface of the recording paper conveyed from the paper cassette (not shown) by the secondary transfer roll 34, and subsequently, in the fixing device 35. It is fixed by heating and pressing. The toner remaining on the surface of the intermediate transfer belt 33 after the secondary transfer is cleaned by the belt cleaner 16 constituted by a cleaning blade for the intermediate transfer belt 33.

  In the present embodiment, a cleaning device 15 and a belt cleaner 16 are provided in a tandem configuration. Even in this type of image forming apparatus, since the toner of each color is mixed in the cleaning unit, the use of the toner set of the present embodiment enables a long-term configuration with a generally short blade life even for a long period of time. Good cleaning characteristics are maintained.

  Note that the process cartridge in the present embodiment is, for example, a cartridge that includes each developing device of reference numerals 5, 6, 7, and 8 in FIG. 1 and includes a detachable developing unit, or each image forming unit 50 in FIG. Y, M, C, K), which includes 20 (Y, M, C, K) developing devices and includes a detachable developing unit. In addition to the developing unit, for example, the photosensitive member 11, You may have the charging roll 18, the cleaning apparatus 15, etc.

Hereinafter, although this embodiment is described in detail with an example, these do not limit this embodiment at all. In the following description, “part” represents “part by mass” and “%” represents “% by mass” unless otherwise specified.
The toner of this embodiment is obtained by the following method. That is, the following resin particles, colorant particle dispersion, release agent composite particle dispersion, and inorganic particle dispersion are prepared. Next, while a predetermined amount of these are mixed and stirred, a polymer of an inorganic metal salt is added thereto and ionically neutralized to form aggregates of the above particles. Resin particles are additionally added before reaching the desired toner particle diameter to obtain the toner particle diameter. Next, after adjusting the pH of the system from a weakly acidic to a neutral range with an inorganic hydroxide, the mixture is heated to a temperature higher than the glass transition temperature of the resin particles so as to fuse together. After completion of the reaction, a desired toner is obtained through sufficient washing, solid-liquid separation, and drying processes.

<Production of toner>
-Synthesis of crystalline polyester resin (1)-
In a heat-dried three-necked flask, 100 mol% of decanedicarboxylic acid, 100 mol% of nonanediol, and 0.25% of dibutyltin oxide as a catalyst with respect to the total weight of these monomers were added. Under an inert atmosphere with nitrogen gas, the mixture was stirred and refluxed at 180 ° C. for 5 hours with mechanical stirring.

Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was cooled with air, the reaction was stopped, and a crystalline polyester resin (1) was synthesized. The weight average molecular weight (Mw) of the obtained crystalline polyester resin (1) was 24000 and the number average molecular weight (Mn) was 7600 by molecular weight measurement (polystyrene conversion) by gel permeation chromatography. The acid value was 10.5.
Further, the melting point (Tm) of the crystalline polyester resin (A) showed a clear endothermic peak, and the endothermic peak temperature was 72.3 ° C. In addition, the melting point of the crystalline polyester resin and the glass transition point (Tg) of the amorphous polyester resin are determined according to ASTM D3418-8 using a differential scanning calorimeter (manufactured by Mac Science: DSC3110, thermal analysis system 001). It was determined by measuring from 0 ° C. to 150 ° C. under a temperature increase rate of 10 ° C./min. The melting point was the peak temperature of the endothermic peak, and the glass transition point was the temperature at the intersection of the extension line of the base line and the rising line in the stepwise endothermic part.

-Synthesis of Amorphous Polyester Resin (1)-
-Bisphenol A ethylene oxide 2-mol adduct: 10 mol%
-Bisphenol A propylene oxide adduct: 90 mol%
・ Terephthalic acid: 40 mol%
・ Fumaric acid: 40 mol%
-Dodecenyl succinic acid: 20 mol%
The above monomer is charged into a 5 liter flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectifying column. The temperature is raised to 190 ° C. over 1 hour, and the reaction system is uniformly stirred. Then, 0.9% of tin distearate was added to the total weight of these monomers. Further, while distilling off the generated water, the temperature was increased to 240 ° C. over 6 hours from the same temperature, and the dehydration condensation reaction was continued at 240 ° C. for another 3 hours. The glass transition point was 60 ° C. / G, Amorphous polyester resin (1) having a weight average molecular weight of 16000 and a number average molecular weight of 6000 was obtained.

-Synthesis of Amorphous Polyester Resin (2)-
-Bisphenol A ethylene oxide 2-mol adduct: 50 mol%
-Bisphenol A propylene oxide adduct: 50 mol%
-Trimellitic anhydride: 7 mol%
・ Terephthalic acid: 65 mol%
・ Dodecenyl succinic acid: 28 mol%
The reaction was carried out using monomers other than trimellitic anhydride in the same manner as in the amorphous polyester resin (1) until the softening point was 110 ° C. Subsequently, the temperature was lowered to 190 ° C., and 7 mol% of trimellitic anhydride was gradually added, and the reaction was continued for 1 hour at the same temperature. The glass transition point was 56 ° C., the acid value was 11.3 mg KOH / g, and the weight average molecular weight was 78000. An amorphous polyester resin (2) having a number average molecular weight of 7800 was obtained.

-Preparation of resin particle dispersion (1)-
-Crystalline polyester resin (1): 100 parts-Methyl ethyl ketone: 60 parts-Isopropyl alcohol: 15 parts Charge methyl ethyl ketone into a 5 L separable flask, then gradually add the resin, and stir with a three-one motor. The oil phase was obtained by dissolving. The 5 L separable flask containing the oil phase was set to 65 ° C. with a water bath, and a 10% aqueous ammonia solution was gradually added dropwise to the stirred oil phase with a dropper so that the total amount became 5 parts. Further, 230 parts of ion-exchanged water was gradually added dropwise at a rate of 10 ml / min to phase-invert and emulsify, and the solvent was removed while reducing the pressure with an evaporator to obtain a resin particle dispersion (1) containing a crystalline polyester resin (1). ) The resin particles had a volume average particle size of 145 nm. (The resin particle solid content was adjusted to 20% with ion-exchanged water)

-Preparation of resin particle dispersion (2)-
-Amorphous polyester resin (1): 100 parts-Methyl ethyl ketone: 60 parts-Isopropyl alcohol: 15 parts Charge methyl ethyl ketone into a 5 L separable flask, and then gradually add the resin, and stir with a three-one motor. And completely dissolved to obtain an oil phase. The 5 L separable flask containing the oil phase is set to 40 ° C. with a water bath, and 10% aqueous ammonia solution is gradually added dropwise to the stirred oil phase with a dropper so that the total amount becomes 3.5 parts. Further, 230 parts of ion-exchanged water is gradually added dropwise at a rate of 10 ml / min to carry out phase inversion emulsification, and the solvent is removed while reducing the pressure with an evaporator, and the resin particle dispersion containing the amorphous polyester resin (1) is dispersed. A liquid (2) was obtained. The volume average particle diameter of the resin particles was 175 nm. (The resin particle solid content was adjusted to 20% with ion-exchanged water)

-Preparation of resin particle dispersion (3)-
In the preparation of the resin particle dispersion (2), the resin particle dispersion is the same as the preparation of the resin particle dispersion (2) except that the amorphous polyester resin (1) is changed to the amorphous polyester resin (2). A liquid (3) was obtained. The volume average particle diameter of the resin particles was 165 nm. (The resin particle solid content was adjusted to 20% with ion-exchanged water)

-Preparation of Colorant Particle Dispersion 1-
・ Cyan pigment (manufactured by Dainichi Seika Co., Ltd .: ECB-301): 50 parts ・ Ionic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 5 parts ・ Ion-exchanged water: 195 parts The above ingredients were mixed and homogenizer (IKA) After dispersion for 10 minutes by ultra turrax), dispersion processing is performed for 15 minutes at a pressure of 250 MPa using an optimizer (counter-impact type wet pulverizer: Sugino Machine), the central particle size of the colorant particles is 130 nm, and the solid content A 20% colorant particle dispersion 1 was obtained.

-Preparation of Colorant Particle Dispersion 2-
In the preparation of the colorant particle dispersion 1, the colorant is magenta C.I. I. Except for changing to Pigment Red122 pigment (manufactured by Dainichi Seika Co., Ltd .: ECR-186Y), the colorant particles have a center particle size of 120 nm and a solid content of 20.0% in the same manner as in the preparation of colorant particle dispersion 1. A colorant particle dispersion 2 was obtained.

-Preparation of release agent particle dispersion-
・ Olefin wax (melting point: 88 ° C.): 60 parts ・ Ionic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 1.8 parts ・ Ion-exchanged water: 238 parts After sufficiently dispersing with an ultra turrax T50, the dispersion was heated at 110 ° C. with a pressure discharge type gorin homogenizer for 1 hour to obtain a release agent particle dispersion having a center diameter of 180 nm and a solid content of 20%.

-Preparation of color toner 1-
Resin particle dispersion (1): 100 parts Resin particle dispersion (2): 300 parts Resin particle dispersion (3): 300 parts Colorant particle dispersion 1: 50 parts Release agent particle dispersion : 50 parts Above, in a round stainless steel flask, 2.0 parts of the ionic surfactant Neogen RK was added, and then stirred and sufficiently mixed and dispersed. Subsequently, 1N nitric acid aqueous solution was dropped to pH 3.5, and then 0.40 part of polyaluminum chloride was added thereto, and the dispersion operation was continued with an ultra turrax. The flask was heated to 48 ° C. with stirring in an oil bath for heating. After holding at 48 ° C. for 40 minutes, a mixed solution of 100 parts of the resin particle dispersion (2) and 100 parts of the resin particle dispersion (3) was slowly added thereto.
Thereafter, a 1N aqueous sodium hydroxide solution was added to bring the pH of the system to 7.0, and then the stainless steel flask was sealed and gradually heated to 90 ° C. while continuing to stir using a magnetic seal. Hold at 3 ° C. for 3 hours.

After completion of the reaction, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 1 L of ion exchange water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes.
This was repeated five more times, and when the pH of the filtrate became 7.5 and the electric conductivity was 7.0 μS / cmt, solid-liquid separation was performed using No5A filter paper by Nutsche suction filtration. Next, vacuum drying was continued for 12 hours to obtain a color toner 1.
The particle diameter of the color toner 1 was measured with a Coulter counter. The volume average diameter D50 was 5.9 μm, and the particle size distribution coefficient GSDv was 1.25. In addition, the particle shape factor SF1 obtained by shape observation with Luzex was 136.

-Preparation of color toner 2-
In the production of the color toner 1, a color toner 2 was obtained in the same manner as in the production of the color toner 1 except that the amount of polyaluminum chloride used was changed from 0.40 parts to 0.50 parts. The color toner 2 had a volume average diameter D50 of 5.7 μm and a particle size distribution coefficient GSDv of 1.27. In addition, the particle shape factor SF1 determined by shape observation with Luzex was 134.

-Preparation of color toner 3-
In the production of the color toner 1, the amount of the resin particle dispersion (1) used in the initial mixing / dispersion is changed from 100 parts to 170 parts, the amount of the resin particle dispersion (2) used is changed from 300 parts to 330 parts, Color toner 3 was obtained in the same manner as in preparation of color toner 1 except that the amount of the particle dispersion (3) used was changed from 300 parts to 200 parts. The color toner 3 had a volume average diameter D50 of 6.0 μm and a particle size distribution coefficient GSDv of 1.27. Moreover, the shape factor SF1 of the particle | grains calculated | required from the shape observation by Luzex was 133.

-Preparation of color toner 4-
In the production of the color toner 1, a color toner 4 was obtained in the same manner as in the production of the color toner 1 except that 0.40 part of polyaluminum chloride was changed to 0.60 part of calcium chloride. The color toner 4 had a volume average diameter D50 of 6.2 μm and a particle size distribution coefficient GSDv of 1.26. Further, the shape factor SF1 of the particles obtained from the shape observation by Luzex was 137, which was a potato shape.

-Preparation of color toner 5-
In the production of the color toner 1, a color toner 5 was obtained in the same manner as the production of the color toner 1 except that the colorant particle dispersion 1 was changed to the colorant particle dispersion 2. The color toner 5 had a volume average diameter D50 of 6.0 μm and a particle size distribution coefficient GSDv of 1.22. In addition, the particle shape factor SF1 determined by shape observation with Luzex was 135.

-Preparation of color toner 6-
In the production of the color toner 1, the amount of the resin particle dispersion (2) used in the initial mixing / dispersion is changed from 300 parts to 100 parts, the amount of the resin particle dispersion (3) is changed from 300 parts to 500 parts, Color toner 6 was obtained in the same manner as in preparation of color toner 1 except that the amount of aluminum chloride used was changed from 0.40 parts to 0.80 parts. The color toner 6 had a volume average diameter D50 of 6.0 μm and a particle size distribution coefficient GSDv of 1.27. Moreover, the shape factor SF1 of the particle | grains calculated | required from the shape observation by Luzex was 133.

-Preparation of color toner 7-
In the production of the color toner 6, the color toner was prepared in the same manner as in the production of the color toner 6 except that 100 parts of the resin particle dispersion (1) in the initial mixing / dispersion was changed to 100 parts of the resin particle dispersion (3). 7 was obtained. The color toner 7 had a volume average diameter D50 of 6.0 μm and a particle size distribution coefficient GSDv of 1.21. In addition, the particle shape factor SF1 obtained from the shape observation by Luzex was 137.

-Preparation of color toner 8-
In the production of the color toner 1, 300 parts of the resin particle dispersion (3) in the first mixing / dispersion was changed to 300 parts of the resin particle dispersion (2), and 0.40 part of polyaluminum chloride was changed to 0.40 part of calcium chloride. A color toner 8 was obtained in the same manner as in the production of the color toner 1 except for the above. The volume average diameter D50 of the color toner 8 was 6.0 μm, and the particle size distribution coefficient GSDv was 1.27. Moreover, the shape factor SF1 of the particle | grains calculated | required from the shape observation by Luzex was 133.

-Preparation of color toner 9-
In the production of the color toner 1, 100 parts of the resin particle dispersion (1) in the first mixing / dispersion is 500 parts, 300 parts of the resin particle dispersion (2) is 100 parts, and 300 parts of the resin particle dispersion (3). A color toner 9 was obtained in the same manner as in the production of the color toner 1 except that was changed to 100 parts. The volume average diameter D50 of the color toner 9 was 5.8 μm, and the particle size distribution coefficient GSDv was 1.26. Further, the shape factor SF1 of the particle determined by shape observation with Luzex was 130.

-Preparation of transparent toner 1-
-Resin particle dispersion (1): 110 parts-Resin particle dispersion (2): 320 parts-Resin particle dispersion (3): 320 parts-Release agent particle dispersion: 50 parts A transparent toner 1 was obtained in the same manner as in the production of the color toner 1 except that the above-described resin particle dispersion and release agent particle dispersion were used and the colorant particle dispersion 1 was not used. The volume average diameter D50 of the transparent toner 1 was 5.8 μm, and the particle size distribution coefficient GSDv was 1.24. In addition, the particle shape factor SF1 obtained from shape observation by Luzex was 132.

-Preparation of transparent toner 2-
Transparent toner 2 was obtained in the same manner as in the preparation of transparent toner 1 except that the amount of polyaluminum chloride used was changed from 0.40 parts to 0.60 parts in the preparation of transparent toner 1. The volume average diameter D50 of the transparent toner 2 was 6.1 μm, and the particle size distribution coefficient GSDv was 1.23. In addition, the particle shape factor SF1 determined by shape observation with Luzex was 134.

-Preparation of transparent toner 3-
Transparent toner 3 was obtained in the same manner as in the preparation of transparent toner 1 except that the amount of polyaluminum chloride used was changed from 0.40 parts to 0.80 parts in the preparation of transparent toner 1. The volume average diameter D50 of the transparent toner 3 was 5.7 μm, and the particle size distribution coefficient GSDv was 1.27. In addition, the particle shape factor SF1 determined by shape observation with Luzex was 135.

-Preparation of transparent toner 4-
Transparent toner 4 was obtained in the same manner as transparent toner 4 except that the amount of polyaluminum chloride used was changed from 0.40 parts to 1.00 parts in the preparation of transparent toner 1. The volume average diameter D50 of the transparent toner 4 was 6.0 μm, and the particle size distribution coefficient GSDv was 1.24. In addition, the particle shape factor SF1 determined by shape observation with Luzex was 138.

-Preparation of transparent toner 5-
A transparent toner 5 was obtained in the same manner as in the preparation of the transparent toner 5 except that the amount of polyaluminum chloride used was changed from 0.40 parts to 0.60 parts of calcium chloride in the preparation of the transparent toner 1. The volume average diameter D50 of the transparent toner 5 was 6.8 μm, and the particle size distribution coefficient GSDv was 1.20. In addition, the particle shape factor SF1 determined by shape observation with Luzex was 135.

<Preparation of external toner>
100 parts of color toner 1, 0.8 parts of hydrophobic titania treated with decylsilane having an average particle diameter of 15 nm, 1.1 parts of hydrophobic silica (NY50, manufactured by Nippon Aerosil Co., Ltd.), and an average particle diameter of 100 nm After adding 1.0 part of hydrophobic silica (X24, manufactured by Shin-Etsu Chemical Co., Ltd.) and blending for 10 minutes at a peripheral speed of 32 m / s using an N-shell mixer, coarse particles are removed using a sieve of 45 μm mesh. External color toner 1 was obtained.
In addition, color toners 2 to 5 and transparent toners 1 to 5 were prepared in the same manner as external color toners 2 to 5 and transparent external toners 1 to 5, respectively.
The types of pigments used in color toners 1 to 5 and transparent toners 1 to 5, the types and contents of the crystalline polyester resin and amorphous polyester resin contained, and the flocculant (bivalent or higher-valent metal element) The content is shown in Table 1.

<Career production>
Ferrite (trade name EFC-35B, manufactured by Powdertech, weight average particle size; 35 μ): 100 partsToluene: 13.5 parts Methyl methacrylate / perfluorooctyl methacrylate copolymer (polymerization ratio 90:10, Weight average molecular weight 49,000): 2.3 parts, tin oxide-coated barium sulfate (trade name: Pastorlan type IV, manufactured by Mitsui Kinzoku Mining Co., Ltd.): 0.3 parts, Eposter S (melamine resin particles, manufactured by Nippon Shokubai Co., Ltd.): 0 .3 parts The above components except for ferrite were dispersed in a sand mill for 1 hour to prepare a resin coating layer forming solution. Next, this resin coating layer forming solution and ferrite were put in a vacuum degassing kneader and stirred for 20 minutes while reducing the pressure at a temperature of 60 ° C. to form a resin coating layer on the ferrite to obtain a carrier. The volume resistance (22 ° C., humidity 55% ° C.) was 2 × 10 ¹¹ Ωcm.

<Production of developer>
100 parts of a carrier was added to 7 parts of the externally added color toner 1, and mixed for 5 minutes by a ball mill to obtain a color developer 1.
Similarly, color developers 2 to 8 were obtained for color toners 2 to 8, respectively.
Similarly, transparent developers 1 to 5 were obtained for the externally added transparent toners 1 to 5, respectively.

<Examples 1-9, Comparative Examples 1-13>
(Evaluation)
The following evaluation was performed using the color developer and the transparent developer shown in Table 2. Table 2 shows the storage modulus (G1) of the color toner at 80 ° C. and the tangent loss (tan δ) of the color toner at 80 ° C. in the color toner and transparent toner used in the color developer and the transparent developer. G2 / G1 represented by the formula (1) is shown.

[Fixing temperature range evaluation]
The external color toner used in the color developer was fixed at a process speed of 250 mm / sec (= fixing speed) using a modified Doccolor 500 (manufactured by Fuji Xerox Co., Ltd.) having a variable process speed. The fixing temperature range was evaluated by changing in the range of ˜210 ° C. Specifically, the external color toner developer was set at the position of the cyan developing machine, and the applied toner amount was adjusted to 4.5 g / m ² . In the fixing temperature range shown in Table 2, after fixing an unfixed color toner solid image (25 mm × 25 mm), it is bent using a weight with a constant load, and the degree of image loss at that portion is graded, The lowest fixing temperature at or above the grade was defined as the minimum fixing temperature, the minimum fixing temperature at which the toner component was transferred to the fixing member (hot offset) was defined as the maximum fixing temperature, and the minimum fixing temperature and the maximum fixing temperature were defined as the fixing temperature range.

[Measurement of image gloss]
For the evaluation of image glossiness, a solid image was formed on J paper (manufactured by Fuji Xerox Co., Ltd.) using only a color developer, and fixed at a fixing temperature of 160 ° C. The 60 ° glossiness was measured with a declination glossmeter (Digital Surgery Glossometer, manufactured by Suga Test Instruments Co., Ltd.) (image glossiness of color toner only). The amount of color toner applied at this time was adjusted to 4.5 g / m ² . The results are shown in Table 2.

Next, the transparent developer is further set at the position of the yellow developing machine, and in the same manner as described above, an image in which a transparent image is formed on the solid image using only the color developer is formed on J paper. Fixing was performed at a fixing temperature of 160 ° C., and the 60 ° glossiness of the image after fixing was measured with a declination gloss meter (digital revolution gloss meter manufactured by Suga Test Instruments Co., Ltd.) (color toner + transparent toner image) Gloss). At this time, the loading amount of the color toner and the loading amount of the transparent toner were both adjusted to 4.5 g / m ² . The results are shown in Table 2.

[Toner blister evaluation]
A color developer is set at the cyan developing machine position of the modified Docucolor 500, a transparent developer is set at the yellow developing machine position, and a paper made by Fuji Xerox, OKTOP coated paper (256 gsm) at 28 ° C. and 85% RH environment. On the solid image using the color developer, an image having a transparent image formed thereon was formed and fixed at a fixing temperature of 180 ° C., and the obtained fixed image was checked for the presence of blisters. When it was visually recognized that a blister was generated and the image was disturbed, it was determined. The results are shown in Table 2.

[Evaluation of image intensity]
In the modified Docucolor 500, the same color toner developer is set at the position of the cyan developer machine and the position of the yellow developer machine, the toner applied amount is adjusted to 9.0 g / m ^2, and on the OKTOP coated paper (256 gsm), A solid image was formed, fixed at a fixing temperature of 160 ° C., and pencil hardness was measured. By this scratching, the minimum hardness of the pencil hardness at which omission in the toner fixed image could be visually confirmed was defined as the image strength.

  As shown in Table 2, in Examples 1 to 9, the color toner alone had a wide fixing temperature range with good fixing, a glossiness of 40 or more, and good color development. In addition, a transparent toner particle layer is provided on the color toner particle layer, and fixing is performed. The glossiness of the color toner is less than 10 compared to the glossiness of the color toner alone, indicating a high glossiness and occurrence of blisters. No high quality images were obtained. On the other hand, in Comparative Examples 1, 4, 7, 8, 10, and 11, since the elastic modulus of the transparent toner is smaller than that of the color toner, blistering occurs when the transparent toner particle layer is provided on the color toner particle layer and fixed. did. In Comparative Examples 2, 3, 5, 6, and 9, the difference between the glossiness of the color toner alone and the glossiness of the color toner + transparent toner is as large as 10 or more, and the uniformity of glossiness as a whole is x. It was. Furthermore, in Comparative Example 12, although the glossiness of the color toner alone was high, the fixing temperature range with good fixing was narrow. In Comparative Example 13, the image intensity of the color toner alone was low, and image loss was likely to occur due to writing of an pencil or the like on the image.

  Examples 1 to 9 were evaluated in the same manner as in the case of a process speed of 240 mm / sec except that the process speed was further fixed at 600 mm / sec (= fixing speed). The image gloss was measured at a fixing temperature of 180 ° C., and the glossiness of only the color toner was 40 or more, and the difference from the case where the transparent toner was placed was less than 10, and the toner blister was observed at the fixing temperature of 200 ° C. However, it did not occur.

1 is a schematic diagram illustrating an example of an image forming apparatus according to an exemplary embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Photoconductor 12 Drive roll 13 Support roll 15 Cleaning apparatus 16 Belt cleaner 17 Primary transfer roll 18 Charging roll 19 Exposure apparatus 20 Developing apparatuses 21, 23, 24 Belt roller 22 Support rollers 14, 25 Bias roller (second transfer means)
26 Electrode roller 34 Secondary transfer roll 35 Fixing device 41 Recording paper 42 Paper feed roller 43 Conveying roller 44 Peeling claw 50 Image forming unit

Claims (7)

It is composed of one or more color toners selected from the group consisting of magenta toner, cyan toner and yellow toner, and transparent toner,
The color toner has a storage elastic modulus (G1) at 80 ° C. of 10 ⁴ Pa to 10 ⁶ Pa,
Tangent loss (tan δ) at 80 ° C. of the color toner is 1.0 or more and 2.5 or less,
A toner set, wherein the storage elastic modulus (G2) of the transparent toner at 80 ° C. and the storage elastic modulus (G1) of the color toner at 80 ° C. satisfy the relationship of the following formula (1).
1.1 ≦ G2 / G1 ≦ 3.0 (1)   The color toner and the transparent toner each contain a divalent or higher metal element, and the amount of the divalent or higher metal element contained in the transparent toner is greater than the amount of the divalent or higher metal element contained in the color toner. The toner set according to claim 1, wherein the toner set is large.   The color toner and the transparent toner each contain a crystalline resin, and the content of the crystalline resin in each toner is 4% by mass or more and 20% by mass or less. The toner set described. It is composed of a developer that includes at least one color toner selected from the group consisting of magenta toner, cyan toner, and yellow toner, and transparent toner,
The color toner has a storage elastic modulus (G1) at 80 ° C. of 10 ⁴ Pa to 10 ⁶ Pa,
Tangent loss (tan δ) at 80 ° C. of the color toner is 1.0 or more and 2.5 or less,
The electrostatic latent image developer, wherein the storage elastic modulus (G1) of the transparent toner at 80 ° C. and the storage elastic modulus (G1) of the color toner at 80 ° C. satisfy the relationship of the following formula (1): set.
1.1 ≦ G2 / G1 ≦ 3.0 (1)   5. A process cartridge comprising at least a developer holder and containing the electrostatic latent image developer set according to claim 4. An image carrier, an electrostatic latent image forming unit for forming an electrostatic latent image on the image carrier, and developing the electrostatic latent image on the image carrier with a developer containing color toner and transparent toner Developing means for forming a color toner image and a transparent toner image by developing with an agent, a transfer means for transferring the color toner image and the transparent toner image onto the transfer body while superposing them, and on the transfer body Fixing means for fixing the transferred toner image,
The image forming apparatus according to claim 4, wherein the electrostatic latent image developer set according to claim 4 is used as the developer including the color toner and the developer including the transparent toner.   The image forming apparatus according to claim 6, wherein the fixing speed is 240 mm / s or more and 600 mm / s or less.

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