JP5444909B2 - Transparent toner for developing electrostatic latent image, electrostatic latent image developer, toner cartridge, process cartridge, and image forming apparatus - Google Patents

Description

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

In Patent Document 1, it is satisfied that, in an electrostatic charge image developing toner containing at least a binder resin and a release agent, the release agent is 0.5 to 20 in the proportion of branched carbon by ¹³ C-NMR. In the DSC curve measured by a differential scanning calorimeter, the endothermic onset temperature is in the range of 50 to 100 ° C. with respect to the endothermic peak at the time of temperature rise and the exothermic peak at the time of temperature fall. For electrostatic image development, wherein at least one endothermic peak P1 is present in the region of 130 ° C., and the maximum exothermic peak at the time of temperature fall is within the range of the peak temperature ± 20 ° C. of the endothermic peak P1. Toner has been proposed.

In Patent Document 2, toner mother particles containing at least a binder resin and a colorant, an average primary particle diameter of 80 to 300 nm having a hydrophobic surface, a water content of 3 to 15%, and a volume resistivity of 1 × are disclosed. An electrostatic charge image developing toner comprising sol-gel silica of 10 ¹³ Ωcm or more is disclosed.
Japanese Patent Laid-Open No. 10-73952 JP 2002-108001 A

  According to the present invention, compared to a case where an external additive having a moisture content in a specific range is not used, it is possible to prevent a fixed image from adhering to another transferred material when the transferred material is superimposed after image fixing. It is an object of the present invention to provide a transparent toner for developing an electrostatic latent image.

That is, the invention according to claim 1
Toner particles containing a binder resin and a release agent having a melting temperature of 60 ° C. or more and 120 or less, and an external additive having a moisture content of 5% by mass or more and 15% by mass or less,
An endothermic peak Tm derived from the release agent in the toner particles in the temperature rising process measured by a differential scanning calorimeter (DSC) based on the ASTM method, and the mold release in the toner particles in the temperature lowering process. The toner for developing an electrostatic latent image has a difference (Tm−Tc) from the exothermic peak Tc derived from the agent to 10 ° C. or more and 50 ° C. or less.

The invention according to claim 2
2. The electrostatic latent image developing transparent toner according to claim 1, wherein the external additive has irregularities on the surface.

The invention according to claim 3
When the BET specific surface area of the external additive is A (m ² / g) and the spherical equivalent specific surface area of the external additive is a (m ² / g), the value of A / a is 1.1 or more and 10. The transparent toner for developing an electrostatic latent image according to claim 1, wherein the toner is 0 or less.
[Here, the spherical equivalent specific surface area a is such that when the volume average particle diameter of the external additive is d (unit: μm) and the true specific gravity of the external additive is ρ (unit: dimensionless), a = 6 / (d × ρ). ]

The invention according to claim 4
An electrostatic latent image developer comprising the transparent toner for developing an electrostatic latent image according to any one of claims 1 to 3.

The invention according to claim 5
The electrostatic latent image developer according to claim 4, comprising a carrier containing a white conductive agent.

The invention according to claim 6
A toner cartridge that accommodates the transparent toner for developing an electrostatic latent image according to any one of claims 1 to 3.

The invention according to claim 7 provides:
A process cartridge comprising a developing device that accommodates the electrostatic latent image developer according to claim 4.

The invention according to claim 8 provides:
A latent image carrier,
Electrostatic latent image forming means for forming an electrostatic latent image on the latent image holding member;
Developing means for developing the electrostatic latent image formed on the latent image holding member as a toner image with the electrostatic latent image developer according to claim 4;
Transfer means for transferring the toner image formed on the latent image holding member to a transfer target;
And a fixing unit that fixes the toner image transferred to the transfer target.

The invention according to claim 9 is:
The image forming apparatus according to claim 8, wherein the process speed is 500 mm / sec or more.

  According to the first aspect of the present invention, compared to the case where an external additive having a moisture content in a specific range is not used, the fixed image is transferred to another transferred material when the transferred material is overlapped after fixing the image. Adhesion is suppressed.

  According to the second aspect of the present invention, a decrease in charge of the toner is suppressed as compared with the case where the surface of the external additive is not uneven.

  According to the third aspect of the present invention, the decrease in charge of the toner is suppressed as compared with the case where the value of A / a of the external additive is out of the above range.

  According to the fourth aspect of the present invention, compared to a case where the toner does not contain an external additive having a moisture content in a specific range, the fixed image is transferred to another transferred object when the transferred object is overlapped after the image is fixed. Attaching to the body is suppressed.

  According to the fifth aspect of the present invention, when the carrier piece is transferred to the transfer medium together with the toner as compared with the case where the conductive agent other than the white conductive agent is used, the carrier piece appears in the toner image. It becomes difficult to hit.

  According to the sixth aspect of the present invention, compared to the case where the toner does not contain an external additive having a moisture content within a specific range, the fixed image is transferred to another transferred object when the transferred object is overlaid after the image is fixed. Attaching to the body is suppressed.

  According to the seventh aspect of the present invention, compared to the case where the toner does not contain an external additive having a moisture content in a specific range, the fixed image is transferred to another transferred object when the transferred object is overlaid after the image is fixed. Attaching to the body is suppressed.

  According to the eighth aspect of the invention, compared to the case where the toner does not contain an external additive having a moisture content in a specific range, the fixed image is transferred to another transferred object when the transferred object is overlaid after the image is fixed. Attaching to the body is suppressed.

  According to the ninth aspect of the present invention, compared to the case where the toner does not contain an external additive having a moisture content in a specific range, the transferred object after image fixing even if the process speed is 500 mm / sec or more. It is possible to prevent the fixed image from adhering to other transferred objects when the images are stacked.

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

[Transparent toner for electrostatic latent image development]
The electrostatic latent image developing transparent toner according to the present embodiment (hereinafter sometimes referred to as “transparent toner”) includes toner particles containing a binder resin and a release agent, and external particles attached to the surface of the toner particles. The moisture content of the external additive is 5% by mass or more and 15% by mass or less. The transparent toner is measured by a differential scanning calorimeter (DSC) by the ASTM method. The endothermic peak derived from the release agent in the toner in the temperature rising process is Tm, and the exothermic peak derived from the release agent in the toner in the temperature lowering process. Is Tc, the difference between Tm and Tc (Tm−Tc) is 10 ° C. or more and 50 ° C. or less.
In the present embodiment, the transparent toner is a toner used for a transparent toner image, and specifically refers to a colorless toner in which the content of a colorant such as a dye or pigment is 0.01% by mass or less. .
In this embodiment, a toner using a release agent having a melting temperature of 60 ° C. or higher and 120 ° C. or lower is used as the release agent.

Since the transparent toner of the present embodiment has the above-described configuration, it is possible to prevent the fixed image from adhering to another transfer target when the transfer target is overlapped after the image is fixed. The reason is not clear, but is presumed as follows.
After an image formed product (hereinafter sometimes referred to as “printed product”) having a toner image fixed on a transfer target is discharged from the fixing device, the next printed product is discharged and stacked. May remain as residual heat in the printed matter, and the residual heat may be accumulated. However, in this embodiment, since the moisture content of the external additive is in the above range, the residual heat is used as the heat of vaporization of the water contained in the external additive, so that the release agent that has oozed out on the fixed image surface is cooled. It is thought that crystallization is promoted. For this reason, the release agent that has oozed out on the surface of the fixed image is rapidly solidified, so that even if the discharged printed material is stacked and the fixed image directly contacts another printed material, the image portion is less likely to adhere. It is considered that image defects due to adhesion of the image portion are suppressed.

  In the transparent toner of this embodiment, the difference between Tm and Tc (Tm−Tc) is 10 ° C. or more and 50 ° C. or less as described above. If the difference between Tm and Tc is small, the mold release agent melted by heating tends to crystallize with cooling. However, if the difference between Tm and Tc is 10 ° C. or more as in this embodiment, it is considered that crystal growth due to cooling of the release agent in the toner is suppressed as compared to a case where the difference is lower than 10 ° C. For this reason, the release agent domain shape in the fixed image is suppressed from being flattened with the crystal growth of the release agent present in the toner, and the fixing is caused by the flatness of the release agent domain shape. It is considered that light irregular reflection on the image surface is suppressed, and uneven glossiness of the fixed image is suppressed. On the other hand, as described above, the release agent that oozes out on the surface of the fixed image is cooled and solidified more rapidly than the release agent present in the fixed image due to the evaporation of moisture contained in the external additive. For this reason, it is considered that the suppression of the adhesion of the image portion and the suppression of uneven gloss are compatible.

  As described above, the moisture content of the external additive is 5% by mass to 15% by mass, preferably 7% by mass to 13% by mass, and more preferably 8% by mass to 10% by mass. When the moisture content of the external additive is 5% by mass or more, the adhesion of the image portion is suppressed as compared with the case where the moisture content is less than 5% by mass. On the other hand, when the moisture content of the external additive is higher than 15% by mass, heat is required to increase the temperature of the moisture, so that the moisture is less likely to evaporate. It is thought that rapid cooling of the mold becomes difficult. Therefore, it is considered that when the moisture content is 15% by mass or less, the adhesion of the image portion is suppressed as compared with the case where the moisture content is higher than 15% by mass.

  Here, the moisture content of the external additive is measured as follows. First, a toner is added to a 1: 1 mixed solution of methanol and water, suspended, and subjected to ultrasonic waves, and then separated into toner particles and an external additive by a centrifuge, and the suspension containing the external additive Remove the supernatant liquid. Next, after the supernatant is dried to obtain a dried external additive, the dried external additive is stored in a constant temperature bath at 30 ° C. and 80% for 24 hours. Then, the moisture content of the external additive after being stored in the thermostat is measured with a heat-drying moisture meter.

  Moreover, the difference of Tm and Tc is 10 degreeC or more and 50 degrees C or less as mentioned above, 15 degreeC or more and 45 degrees C or less are more preferable, and 25 degreeC or more and 35 degrees C or less are more preferable. When the difference between Tm and Tc is 10 ° C. or more, uneven gloss of the fixed image is suppressed as described above. It is technically difficult to make the difference between Tm and Tc greater than 50 ° C.

  In addition, said Tm and Tc based on ASTM method (D3418-8) by a differential scanning calorimeter (DSC) are calculated | required with the following method. 1) Put 10 mg of sample in an aluminum cell and cover it (this is called a sample cell). For comparison, 10 mg of alumina is similarly put in an aluminum cell of the same type and covered (this is called a comparison cell). 2) Each of the sample cell and the comparison cell is set in a measuring device, heated from 30 ° C. to 200 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere, and left at 200 ° C. for 10 minutes. 3) After standing, the temperature is lowered to −30 ° C. at a temperature decreasing rate of −10 ° C./min using liquid nitrogen and left at −30 ° C. for 10 minutes. 4) After standing, the temperature is raised from −30 ° C. to 200 ° C. at a temperature raising rate of 20 ° C./min. During the operation of 4), an endothermic / exothermic curve is obtained. Tm and Tc are determined from the obtained endothermic / exothermic curve. As a measuring device, a differential scanning calorimeter DSC-7 manufactured by Perkin Elmer was used.

In the obtained endothermic / exothermic curve, whether or not Tm and Tc are derived from the release agent contained in the toner is determined as follows.
First, the toner was dissolved in toluene heated to 180 ° C. and then cooled, and only the release agent crystallized was collected. About the obtained mold release agent, the endothermic peak in the temperature rising process was calculated | required by DSC similarly to the above. At this time, if the Tm of the toner matches the endothermic peak of only the release agent, it is determined that the Tm of the toner is derived from the release agent contained in the toner.
Next, toluene of the remaining toner-dissolved toluene when only the release agent was collected was volatilized, and the exothermic peak in the temperature lowering process was determined by DSC for the remaining solid content in the same manner as described above. Since the exothermic peak at this time is derived from other than the release agent, the Tc of the toner other than these peaks is determined to be derived from the release agent.

  In the present embodiment, it is preferable that irregularities exist on the surface of the external additive. Due to the presence of irregularities on the surface of the external additive, a decrease in charge of the toner is suppressed. The reason is not clear, but is presumed as follows. If irregularities exist on the surface of the external additive, it is considered that moisture enters the concave portions of the irregularities. Therefore, compared to an external additive having the same moisture content and no irregularities on the surface, the surface of the external additive is in contact with the outside (for example, the convex portion of the external additive having irregularities on the surface). It is believed that the amount of water retained is relatively low. Therefore, when an external additive having a moisture content in the above range and having irregularities on the surface is used, in addition to the effect of suppressing the adhesion of the image area, the effect of suppressing the decrease in charging of the toner due to the moisture is also obtained. It is thought that. In addition, an external additive having irregularities on the surface has a large surface area compared to an external additive having no irregularities on the surface and the same particle size, and thus a high moisture content is easily obtained.

  Among the external additives having irregularities on the surface, in particular, porous particles having irregularities including pores that lead from the outside to the inside are preferable. When the external additive is a porous particle, moisture easily enters the inside of the particle by capillary action, and moisture is retained inside the particle, so that a higher moisture content is easily obtained. Similarly to the above, since the amount of water held in the region in contact with the outside is relatively small, it is easy to obtain the effect of suppressing the toner charge reduction.

Furthermore, in this embodiment, when the BET specific surface area of the external additive is A (m ² / g) and the spherical equivalent specific surface area of the external additive is a (m ² / g), the value of A / a is 1. It is preferably 1 or more and 10.0 or less, more preferably 2.0 or more and 8.0 or less, and further preferably 3.0 or more and 6.0 or less. The presence of irregularities to such an extent that the value of A / a of the external additive is in the above range, the amount of moisture held in the region in contact with the outside compared to the case where the value of A / a is smaller than the above range. Since the amount is relatively small, a decrease in charging of the toner is suppressed. In addition, since the A / a value is in the above range, it has pores of an appropriate size for retaining moisture as compared with the case where the A / a value is larger than the above range, and thus has a high moisture content. Is easy to obtain.

  The BET specific surface area A of the external additive is measured as follows. Specifically, using a BET specific surface area meter (SA3100, manufactured by Beckman Coulter, Inc.) as a measuring device, 0.1 g of an external additive as a measurement sample is precisely weighed, put in a sample tube, and then degassed. A numerical value obtained by automatic measurement by the multipoint method is defined as a BET specific surface area A.

The spherical equivalent specific surface area a of the external additive is represented by the following formula (1).
Formula (1): a = 6 / (d × ρ)
Here, d is the volume average particle size (unit: μm) of the external additive, and ρ is the true specific gravity (unit: dimensionless) of the external additive.

Since the spherical equivalent surface area a is a specific surface area per unit mass when the external additive particles are assumed to be perfectly smooth spheres, it is derived as follows.
When the volume average particle diameter of the external additive is d (μm), the surface area S (m ² ) and volume V (m ² ) of one external additive particle are expressed by the following formulas (2) and (3). The
Formula (2): S = 4π × {(d / 2) × 10 ⁻⁶ } ²
Formula (3): V = (4/3) × π × {(d / 2) × 10 ⁻⁶ } ³
When the true specific gravity of the external additive is ρ (dimensionless), the density of the external additive is represented by ρ × 10 ⁶ (g / m ³ ), and the mass M (g) of one external additive particle is It is represented by the following formula (4).
Formula (4): M = V × ρ × 10 ⁶ = (1/6) πρd ³ × 10 ⁻¹²
Therefore, as described above, since the spherical equivalent surface area a is a surface area per unit mass, the above formula (1) is derived as in the following formula (5).
Formula (5): a = S / M = 6 / (d × ρ)

  The volume average particle diameter d of the external additive is measured using a laser diffraction / scattering particle size distribution analyzer (LS Particle Size Analyzer: LS13 320, manufactured by BECKMAN COULTER). For the particle size range (channel) obtained by dividing the obtained particle size distribution, the volume cumulative distribution is subtracted from the small particle size side, and the particle size that becomes 50% cumulative is defined as the volume average particle size d.

Moreover, true specific gravity (rho) of an external additive measures a true specific gravity based on 5-2-1 of JIS-K-0061 using a Le Chatelier specific gravity bottle. The operation is as follows.
(1) Put 250 ml of ethyl alcohol into a Lechatelier specific gravity bottle and adjust so that the meniscus is at the position of the scale.
(2) The specific gravity bottle is immersed in a constant temperature water bath, and when the liquid temperature reaches 20.0 ± 0.2 ° C., the position of the meniscus is accurately read with the scale of the specific gravity bottle. (Accuracy 0.025ml)
(3) A sample is weighed 100 g and its mass is defined as W (g).
(4) Put the weighed sample in a specific gravity bottle and remove the foam.
(5) The specific gravity bottle is immersed in a constant temperature water bath, and when the liquid temperature becomes 20.0 ± 0.2 ° C., the position of the meniscus is accurately read with the scale of the specific gravity bottle. (Accuracy 0.025ml)
(6) The true specific gravity is calculated by the following formula.
D = W / (L2-L1)
ρ = D / 0.9982
In the above formula, D is the density of the sample (20 ° C.) (g / cm ³ ), ρ is the true specific gravity of the sample (20 ° C.), W is the apparent mass (g) of the sample, and L1 is the sample in a specific gravity bottle. The previous meniscus reading (20 ° C.) (ml), L2 is the meniscus reading after placing the sample in the density bottle (20 ° C.) (ml), 0.9982 is the density of water at 20 ° C. (g / cm ³ ).

Below, each component which comprises the transparent toner which concerns on this embodiment is demonstrated.
The toner according to the exemplary embodiment includes toner particles and an external additive attached to the surface of the toner particles. The toner particles include a binder resin, a release agent, and other additives as necessary.

<External additive>
The external additive is not limited as long as it is a particle attached to the surface of the toner particles, and examples thereof include inorganic particles and organic particles.
Examples of inorganic particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride, Examples include Bengala, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, and silicon nitride. Among these, silica particles or titania particles are preferable.

  Examples of organic particles include polystyrene particles, polymethyl methacrylate particles, polyvinylidene fluoride particles, particles such as vinyl resins, polyester resins, and silicone resins, and particles of fatty acid amides such as ethylene bisstearyl amide and oleic amide. And particles of fatty acid metal salts such as zinc stearate and calcium stearate.

  The moisture content of the external additive is 5% by mass or more and 15% by mass or less as described above. As a method of controlling the moisture content of the external additive, for example, a method of controlling the moisture content by forming irregularities on the surface of the external additive and controlling the value of A / a, or the surface of the external additive The method of controlling a moisture content by processing this etc. is mentioned, You may control a moisture content using these together.

  As a method of manufacturing an external additive having irregularities on the surface, for example, after forming primary particles, instead of growing the primary particles, a flocculant and a catalyst are added to form secondary particles in which the primary particles are aggregated. And a method of using the secondary particles as an external additive. Since the external additive produced by this method has irregularities formed by pores communicating from the outside to the inside, it is easy to efficiently retain moisture, and the moisture content is easily within the above range.

As the flocculant, for example, a monomer used for forming primary particles may be used as the flocculant, and a general flocculant (for example, aluminum sulfate, polyaluminum chloride, etc.) may be used.
A monomer is selected according to the kind of particle | grains to form, Specifically, tetraethoxysilane, tetramethoxysilane, titanium isopropoxide, titanium tetrabutoxide etc. are mentioned, for example.
Examples of the catalyst include 20% aqueous ammonia, 5% hydrochloric acid, and the like.
As a volume average particle diameter of the said primary particle, the range of 0.01 micrometer or more and 0.05 micrometer or less is mentioned, for example. Moreover, as a volume average particle diameter of the said secondary particle, the range of 0.06 micrometer or more and 0.30 micrometer or less is mentioned, for example.

  When producing an external additive having irregularities on the surface by the above method, the rate at which the catalyst is dropped into the monomer solution when forming primary particles is slower than when producing conventional external additives without irregularities. It is preferable to do. The specific dropping rate of the catalyst varies depending on the monomer used and the type of the catalyst. For example, when tetraethoxysilane is used as the monomer and 20% aqueous ammonia is used as the catalyst, the dropping rate is 0.5 g / min or more 6 0.0 g / min or less is desirable.

  Examples of the method of treating the surface of the external additive include a method of hydrophobizing using a hydrophobizing agent. Specific examples of the hydrophobizing agent include methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, diphenyldimethoxysilane, vinyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ- Chloropropyltrimethoxysilane, γ-bromopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, fluoroalkyltrimethoxysilane, hexamethyldisilazane Silane coupling agents such as titanate coupling agents; aluminate coupling agents; and the like.

The addition amount of the external additive is preferably in the range of 0.1 to 5 parts by mass, more preferably in the range of 0.3 to 2 parts by mass with respect to 100 parts by mass of the toner particles.
Examples of the method of attaching the external additive to the toner particles include a method of adding using a V-type blender, a Henschel mixer, a Redige mixer, etc., and attaching the external additive to the toner particles in stages. Also good.
In the present embodiment, as long as the external additive having the above-described moisture content in the above range is externally added to the toner particles, other external additives may be further externally added.

<Toner particles>
(Binder resin)
As the binder resin, known resin materials such as a styrene / acrylic resin, an epoxy resin, a polyester resin, a polyurethane resin, a polyamide resin, a cellulose resin, a polyether resin, and a polyolefin resin are used, and a polyester resin is particularly desirable.

Hereinafter, the polyester resin will be mainly described to represent the amorphous resin in the present embodiment.
Examples of the polyester resin desirably used in the present embodiment include those obtained by polycondensation of polyvalent carboxylic acids and polyhydric alcohols.
Examples of polyvalent carboxylic acids include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalene dicarboxylic acid; maleic anhydride, fumaric acid, succinic acid, alkenyl Aliphatic carboxylic acids such as succinic anhydride and adipic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, and the like. These polyvalent carboxylic acids may be used alone or in combination. Among these polyvalent carboxylic acids, it is desirable to use aromatic carboxylic acids. Further, a trivalent or higher carboxylic acid (trimellitic acid or its acid anhydride) may be used in combination with the dicarboxylic acid.

  Examples of the polyhydric alcohol in the polyester resin include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentylglycol, and glycerin; cyclohexanediol, cyclohexanedimethanol, Examples thereof include alicyclic diols such as hydrogenated bisphenol A; aromatic diols such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A. One or more of these polyhydric alcohols may be used. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferred, and among these, aromatic diols are more desirable. Further, a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) may be used in combination with the diol.

Moreover, the weight average molecular weight (Mw) of the polyester resin is preferably 5000 or more and 50000 or less, and more preferably 7000 or more and 20000 or less.
In the present embodiment, the weight average molecular weight is measured with a THF solvent using a Toso GPC / HLC-8120, a Tosoh column TSKgel SuperHM-M (15 cm), and a monodisperse polystyrene. This is calculated using a molecular weight calibration curve prepared with a standard sample.

  As for the glass transition temperature (Tg) of the said polyester resin, it is desirable that it is the range of 50 to 80 degreeC. The Tg of the polyester resin is more preferably 50 ° C. or higher and 65 ° C. or lower.

  If necessary, a polycarboxylic acid or a polyhydric alcohol may be added at the final stage of the synthesis for the purpose of adjusting the acid value or the hydroxyl value. Examples of polycarboxylic acids include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid; maleic anhydride, fumaric acid, succinic acid, alkenyl Aliphatic carboxylic acids such as succinic anhydride and adipic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid; 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4- Examples thereof include aromatic carboxylic acids having at least three carboxyl groups in one molecule such as naphthalene tricarboxylic acid.

  Examples of polyhydric alcohols include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin; cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc. And aromatic diols such as bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct.

The production of the polyester resin can be carried out at a polymerization temperature of 180 ° C. or higher and 230 ° C. or lower. The reaction system is reduced in pressure as necessary and reacted while removing water and alcohol generated during condensation.
When the polymerizable monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizing solvent and dissolved. In this case, the polycondensation reaction is performed while distilling off the solubilizing solvent. If there is a polymerizable monomer having poor compatibility in the copolymerization reaction, the polymerizable monomer having poor compatibility and the polymerizable monomer and the acid or alcohol to be polycondensed are condensed in advance. And then polycondensation with the main component.

  Catalysts used in the production of the polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; zinc, manganese, antimony, titanium, tin, zirconium, germanium and the like Metal compounds; phosphorous acid compounds; phosphoric acid compounds; and amine compounds.

(Release agent)
Examples of the release agent include paraffin waxes such as low molecular weight polypropylene and low molecular weight polyethylene; silicone resins; rosins; rice wax; carnauba wax; ester wax; Among these, paraffin wax, ester wax, montan wax and the like are preferable, and paraffin wax, ester wax and the like are more preferable. The melting temperature of the release agent used in this embodiment is preferably 60 ° C. or higher and 120 ° C. or lower, and more preferably 70 ° C. or higher and 110 ° C. or lower. The content of the release agent in the toner is desirably 0.5% by mass or more and 15% by mass or less, and more desirably 1.0% by mass or more and 12% by mass or less.

(Other additives)
In addition to the above components, various components such as an internal additive, a charge control agent, inorganic powder (inorganic particles), and organic particles may be added to the toner particles as necessary.
Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese, alloys, and magnetic materials such as compounds containing these metals.

  The inorganic particles are added for various purposes, but may be added for adjusting the viscoelasticity of the toner. By adjusting the viscoelasticity, image glossiness and penetration into paper are adjusted. As the inorganic particles, known inorganic particles such as silica particles, titanium oxide particles, alumina particles, cerium oxide particles, or those obtained by hydrophobizing the surfaces thereof may be used alone or in combination of two or more. Further, the silica particles may be subjected to various surface treatments, and for example, those subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a silicone oil or the like are preferably used.

(Characteristics of toner particles)
The volume average particle diameter of the toner particles is preferably in the range of 4 μm to 9 μm, more preferably in the range of 4.5 μm to 8.5 μm, and still more preferably in the range of 5 μm to 8 μm.
The volume average particle size is measured with a Coulter Multisizer II (manufactured by Coulter, Inc.) with an aperture diameter of 50 μm. At this time, the measurement was performed after the toner was dispersed in an electrolyte aqueous solution (Isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

Further, the shape factor SF1 of the toner particles is preferably spherical in the range of 110 to 140, and more preferably in the range of 110 to 130.
Here, the shape factor SF1 is obtained by the following equation.
SF1 = (ML ² / A) × (π / 4) × 100 (wherein ML represents the absolute maximum length of the toner, and A represents the projected area of the toner).

  The SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and is calculated as follows, for example. That is, an optical microscope image of particles scattered on the surface of a slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length and projected area of 100 particles are obtained, calculated by the above formula, and an average value thereof is obtained. Is obtained.

In this embodiment, there is no particular limitation on the method of setting the difference between Tm and Tc to 10 ° C. or more and 50 ° C. or less. For example, a method of including a metal element such as Al in the release agent domain of the toner particles can be mentioned. . Metal elements such as Al have a function as a crystal inhibitor for the release agent. Furthermore, a metal element such as Al ionically bonds to the binder resin of the toner particles, and has an effect of inhibiting the crystal growth of the release agent. As a result, the difference between Tm and Tc is set to 10 ° C. or more and 50 ° C. or less. Thereby, the occurrence of uneven gloss after fixing is further effectively suppressed.
The metal element contained in the release agent domain is preferably Al since it has a high valence and is effective in suppressing crystallization of the release agent due to ionic bonds.

Whether or not a metal element such as Al is contained in the release agent domain is confirmed by the following method. First, the toner particles are embedded using a bisphenol A type liquid epoxy resin and a curing agent, and then a cutting sample is prepared. Next, the cutting sample is cut at −100 ° C. using a cutting machine using a diamond knife, for example, LEICA ultramicrotome (manufactured by Hitachi Technologies) to prepare an observation sample. Further, this observation sample is left in a desiccator under a ruthenium tetroxide atmosphere for dyeing. Judgment of dyeing is judged by the degree of dyeing of the tape that has been left at the same time. The observation sample stained in this way is observed with a TEM at a magnification of around 5000 times.
Since the toner sample is dyed with ruthenium tetroxide, the binder resin and the release agent are discriminated from the difference in density and shape of the dye. The portions presenting in the shape of sticks and lumps inside the toner and having a whiter contrast were determined to be release agent domains.
Next, a metal element such as Al in the release agent domain is mapped at an acceleration voltage of 20 kV using an energy dispersive X-ray analyzer EMAX model 6923H (manufactured by HORIBA) with an observation sample attached to the electron microscope S4100. It was determined whether or not a metal element was contained in the mold agent domain.

The content of Al in the release agent domain by X-ray fluorescence analysis is preferably 0.005 atom% or more and 0.05 atom% or less, particularly preferably 0.01 atom% or more and 0.05 atom% or less.
The measurement of the content of Al in the release agent domain is performed as follows.
Specifically, first, the toner particles are embedded and cut by the above method, the cross section of the prepared observation sample is dyed, and observed by TEM to determine the release agent domain. Then, about release agent domain, content of Al is measured using the fluorescent X ray (XRF-1500) of Shimadzu Corporation.

<Toner production method>
The method for producing the toner according to the exemplary embodiment is not particularly limited, and is manufactured by a known dry method such as a kneading / pulverizing method or a wet method such as an agglomeration / union method or a suspension polymerization method. Among these methods, an emulsification aggregation method that can easily produce a toner having a core-shell structure is preferable. Hereinafter, the method for producing the toner of the exemplary embodiment by the aggregation / unification method will be described in detail.

The aggregation / unification method according to the present embodiment includes, for example, a resin particle dispersion adjusting step for adjusting a resin particle dispersion in which binder resin particles are dispersed, and a release agent in which particles of a release agent are dispersed. A release agent particle dispersion adjusting step for adjusting the particle dispersion, an aggregation step for forming an aggregate formed by aggregation of the resin particles and the release agent particles, and a fusion step for fusing the aggregates.
Hereinafter, each step will be described.

(Resin particle dispersion adjustment process)
The resin particle dispersion is produced, for example, by applying a shearing force to a solution obtained by mixing an aqueous medium and a resin with a disperser. At that time, particles may be formed by heating to lower the viscosity of the resin component. A dispersant may be used for stabilizing the dispersed resin particles. Furthermore, if the resin is oily and dissolves in a solvent with a relatively low solubility in water, the resin is dissolved in those solvents and dispersed in water together with a dispersant and a polymer electrolyte, and then heated or decompressed. Then, the resin particle dispersion may be prepared by evaporating the solvent.

Examples of the aqueous medium include water such as distilled water and ion-exchanged water; alcohols; and the like.
Examples of the dispersant used in the emulsification step include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate; sodium dodecylbenzenesulfonate, Anionic surfactants such as sodium octadecyl sulfate, sodium oleate, sodium laurate, potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, amphoteric such as lauryldimethylamine oxide Ionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene Surfactants such as nonionic surfactants such as alkyl amines; and the like are; tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, inorganic salts such as barium carbonate.

  Examples of the disperser used for preparing the emulsion include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser. As the size of the resin particles, the average particle size (volume average particle size) is preferably 1.0 μm or less, more preferably in the range of 60 nm to 300 nm, and still more preferably in the range of 150 nm to 250 nm. .

(Release agent particle dispersion adjustment process)
In preparing the release agent particle dispersion, for example, the release agent is dispersed in water together with an ionic surfactant, a polymer electrolyte such as a polymer acid or a polymer base, and then the melting temperature of the release agent. While being heated to the above temperature, the dispersion treatment is performed using a homogenizer or a pressure discharge type disperser that imparts a strong shearing force. Through this treatment, a release agent particle dispersion is obtained.
By the dispersion treatment, a release agent particle dispersion liquid containing release agent particles having a volume average particle diameter of 1 μm or less is obtained. A more preferable volume average particle diameter of the release agent particles is 100 nm or more and 500 nm or less.

When manufacturing a toner containing a metal element such as Al in the release agent domain, an inorganic metal salt containing a metal element such as Al is dispersed in water together with the release agent in the preparation of the release agent particle dispersion. You may let them.
Specific examples of inorganic metal salts include, for example, 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. And inorganic metal salt polymers.

(Aggregation process)
In the aggregation step, the resin particle dispersion, the release agent particle dispersion, and the like are mixed to form a mixed solution, which is heated and aggregated at a temperature equal to or lower than the glass transition temperature of the resin particles to form aggregated particles. Aggregated particles are formed, for example, by acidifying the pH of the mixed solution with stirring. The pH in the aggregating step is desirably in the range of 2 to 7, and it is effective to use an aggregating agent at this time.
In the agglomeration step, the release agent particle dispersion may be added and mixed at once with various dispersions such as a resin particle dispersion, or may be added in multiple portions.
As the aggregating agent, a surfactant having a polarity opposite to that of the surfactant used for the dispersant, an inorganic metal salt, and a divalent or higher-valent metal complex are preferably used.
Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers.

  Further, a toner having a structure in which the surface of the core aggregated particles is coated with a resin may be prepared by additionally adding a resin particle dispersion when the aggregated particles have a desired particle size (coating step). In the case of additional addition, a flocculant may be added or pH adjustment may be performed before additional addition.

(Fusion process)
In the fusion step, the agglomeration is stopped by raising the pH of the suspension of aggregated particles to a range of 3 to 9 under stirring conditions in accordance with the aggregation step, and the glass transition temperature of the resin is higher than the glass transition temperature. The aggregated particles are fused by heating at a temperature. Moreover, when it coat | covers with the said resin, this resin is also united and a core aggregated particle is coat | covered. The heating time may be performed to the extent that fusion is performed, and may be performed for about 0.5 hour to 10 hours.

Cool after fusion to obtain fused particles. Further, in the cooling step, crystallization may be promoted by lowering the cooling rate at a glass transition temperature of ± 10 ° C., that is, so-called slow cooling.
The fused particles obtained by fusing are subjected to a solid-liquid separation process such as filtration, and if necessary, a toner particle is obtained through a washing process and a drying process. An external additive is added to the obtained toner particles, and a toner is obtained through an external addition step of attaching the external additive to the surface of the toner particles by the above method. Further, if necessary, coarse toner particles may be removed after the external addition step using an ultrasonic sieving machine, a vibration sieving machine, a wind sieving machine, or the like.

The toner according to the present embodiment may constitute a toner set together with at least one color toner selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner.
The colorant used for the colored toner may be a dye or a pigment.
The content of the colorant in the colored toner is desirably in the range of 1 part by mass to 30 parts by mass with respect to 100 parts by mass of the binder resin. It is also effective to use a surface-treated colorant or a pigment dispersant as necessary. By selecting the type of the colorant, yellow toner, magenta toner, cyan toner, black toner and the like can be obtained.

  The colored toner in this embodiment may contain the same components as the toner (transparent toner) according to this embodiment except that it contains a colorant. Further, the preferable range related to the toner characteristics such as the particle diameter is the same as that of the toner according to the exemplary embodiment.

[Electrostatic latent image developer]
The electrostatic latent image developer according to the present embodiment (hereinafter sometimes referred to as “developer”) includes at least the toner according to the present embodiment.
The toner according to the exemplary embodiment is used as it is as a one-component developer or as a two-component developer. When used as a two-component developer, it is used by mixing with a carrier.

  The carrier that can be used in the two-component developer is not particularly limited, and a known carrier is used. Examples thereof include magnetic metals such as iron oxide, nickel and cobalt, magnetic oxides such as ferrite and magnetite, resin-coated carriers having a resin coating layer on the surface of the core material, and magnetic dispersion carriers. Further, a resin-dispersed carrier in which a conductive agent or the like is dispersed in a matrix resin may be used.

  The developer of this embodiment desirably includes a carrier using a white conductive agent. By using a white conductive agent as the conductive agent, the carrier piece is less noticeable in the toner image when the carrier piece is transferred to the transfer target. Examples of the white conductive agent include zinc oxide and titanium oxide.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples include, but are not limited to, an acid copolymer, a straight silicone resin containing an organosiloxane bond or a modified product thereof, a fluororesin, a polyester, a polycarbonate, a phenol resin, and an epoxy resin.

  Examples of the conductive agent include metals such as gold, silver, and copper, and carbon black, as well as titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black, but are not limited thereto. It is not something.

  Examples of the carrier core material include magnetic metals such as iron, nickel and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. The volume average particle diameter of the carrier core material is generally in the range of 10 to 500 μm, and preferably in the range of 30 to 100 μm.

  In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution prepared by dissolving the coating resin and, if necessary, various additives in an appropriate solvent. The solvent is not particularly limited, and may be selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed onto the surface of the carrier core material, and the carrier core material is fluidized air. A fluidized bed method in which the coating layer forming solution is sprayed in a state of being suspended by the above, a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater, and the solvent is removed.

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

[Toner cartridge, process cartridge, and image forming apparatus]
The image forming apparatus according to the present embodiment includes a latent image holding member, and a developing unit that develops the electrostatic latent image formed on the latent image holding member as a toner image with the electrostatic latent image developer according to the present embodiment. A transfer unit that transfers the toner image formed on the latent image holding member to the transfer target; and a fixing unit that fixes the toner image transferred to the transfer target. You may have other means, such as the cleaning means which cleans the transfer residual component of a holding body.

  In the present embodiment, since the developer is used, even if the process speed of the image forming apparatus is high (for example, 500 mm / sec or more), the adhesion of the image portion is suppressed. Specifically, if the process speed of the image forming apparatus is fast, the next print is discharged and stacked before the remaining heat due to image fixing remaining on the discharged printed material is cooled down, so that the remaining heat is easily accumulated and stacked. The temperature of printed materials tends to increase. However, in this embodiment, since the image is formed using the developer, as described above, the release agent that has oozed out on the surface of the fixed image is rapidly cooled and solidified by vaporization of water contained in the external additive. For this reason, it is considered that even if the process speed is high, the adhesion of the image portion is suppressed. Here, the process speed indicates the conveyance speed of the transfer target.

  The image forming apparatus according to the present embodiment includes, for example, a color image forming apparatus that repeatedly performs primary transfer of a toner image held on a latent image holding body such as a photosensitive drum to an intermediate transfer body, and a developing device for each color. It may be a tandem color image forming apparatus in which a plurality of latent image holders provided are arranged in series on an intermediate transfer member.

  In this image forming apparatus, for example, the part including the developing unit may be a cartridge structure (process cartridge) that is detachable from the main body of the image forming apparatus. As the process cartridge, the process cartridge according to the present embodiment that includes at least a developer holder and accommodates the electrostatic latent image developer according to the present embodiment is preferably used.

The image forming apparatus according to the present embodiment will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment. The image forming apparatus according to the present embodiment has a tandem configuration in which a plurality of photosensitive members as latent 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. Image forming units 50T to be arranged are arranged in parallel (tandem) at intervals.
Here, each of the image forming units 50Y, 50M, 50C, 50K, and 50T has the same configuration except for the color of the toner in the stored developer. The unit 50Y will be described as a representative. Note that the same reference numerals with magenta (M), cyan (C), black (K), and transparency (T) are attached to the same parts as the image forming unit 50Y in place of yellow (Y). Description of the image forming units 50M, 50C, 50K, and 50T is omitted. In the present embodiment, the toner according to the present embodiment is used as the toner (transparent toner) in the developer accommodated in the image forming unit 50T.

  The yellow image forming unit 50Y includes a photoconductor 11Y as a latent image holding member, and the photoconductor 11Y has a process speed (image output) determined in advance by a driving unit (not shown) along an arrow A direction shown in the drawing. Speed). As the photoreceptor 11Y, for example, an organic photoreceptor having sensitivity in the infrared region is used.

  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), and the surface of the photoconductor 11Y is predetermined. Charged to a certain potential.

  Around the photoreceptor 11Y, an exposure device (electrostatic latent image forming unit) 19Y that exposes the surface of the photoreceptor 11Y to form an electrostatic latent image on the downstream side in the rotation direction of the photoreceptor 11Y with respect to the charging roll 18Y. Is arranged. In this case, a small LED array is used as the exposure device 19Y because of space, but the present invention is not limited to this, and it is a matter of course that other electrostatic latent image forming means using a laser beam or the like may be used. No problem.

  Further, a developing device (developing unit) 20Y including a developer holding body that holds a yellow developer 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. The electrostatic latent image formed on the surface of the photoreceptor 11Y 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. Are arranged as follows. 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 is primarily transferred, and then each color of magenta, cyan, and black is further transferred. The toner images are sequentially primary-transferred and stacked.

  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. The 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 unit) 34 is pressed against the bias roll 14 that stretches the intermediate transfer belt 33 via the intermediate transfer belt 33. The toner image that is primarily transferred and laminated on the surface of the intermediate transfer belt 33 is applied to the surface of the recording paper (transfer object) P fed from a paper cassette (not shown) at the pressure contact portion between the bias roll 14 and the secondary transfer roll 34. , Electrostatically transferred. At this time, 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). The transparent toner image is at the top.

  Also, downstream of the secondary transfer roll 34, a fixing device (fixing means) for fixing the toner image transferred on the recording paper P onto the surface of the recording paper P by heat and pressure to form a permanent image. 35 is arranged.

  As the fixing device used in this embodiment, for example, a low surface energy material typified by a fluororesin component or a silicone resin is used on the surface, a fixing belt having a belt shape, and a fluororesin component or the like on the surface. Using a low surface energy material typified by a silicone resin, a cylindrical fixing roll can be mentioned.

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

  In the yellow developing unit 50Y, the photoreceptor 11Y rotates in the direction of arrow A at a predetermined process speed. The surface of the photoconductor 11Y is negatively charged to a predetermined potential by the charging roll 18Y. Thereafter, the surface of the photoreceptor 11Y is exposed by the exposure device 19Y, and an electrostatic latent image corresponding to the image information is formed. Subsequently, the negatively charged toner is reversely developed by the developing device 20Y, and the electrostatic latent image formed on the surface of the photoconductor 11Y is visualized on the surface of the photoconductor 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, transfer residual components such as toner remaining on the surface of the photoreceptor 11Y are 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 color mode, each color toner image is transferred in the order of transparent, yellow, magenta, cyan, and black. In the two-color and three-color modes, only the toner image of the required color is used in this order. Or, multiple transfer is performed. Thereafter, the toner image that has been single-transferred or multiple-transferred onto the surface of the intermediate transfer belt 33 is secondarily transferred onto the surface of the recording paper P conveyed from a paper cassette (not shown) by the secondary transfer roll 34, and then the fixing device 35. It is fixed by heating and pressurizing. 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 FIG. 1, in a yellow image forming unit 50Y, a developing device 20Y including a developer holding body for holding a yellow electrostatic latent image developer, a photoconductor 11Y, a charging roll 18Y, and a cleaning device 15Y are integrated. The process cartridge is configured to be attached to and detached from the image forming apparatus main body. The image forming units 50T, 50K, 50C, and 50M are also configured as process cartridges in the same manner as the image forming unit 50Y.

  Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to the present exemplary embodiment is mounted so as to be detachable from the image forming apparatus, and stores toner to be supplied to a developing unit provided in the image forming apparatus. Note that the toner cartridge according to the present embodiment only needs to contain at least toner, and may contain developer, for example, depending on the mechanism of the image forming apparatus.

  Therefore, in the image forming apparatus having a configuration in which the toner cartridge is detachably attached, the toner according to the present embodiment is easily supplied to the developing device by using the toner cartridge containing the toner according to the present embodiment. .

  The image forming apparatus illustrated in FIG. 1 is an image forming apparatus having a configuration in which the toner cartridges 40Y, 40M, 40C, 40K, and 40T are attached and detached. The developing devices 20Y, 20M, 20C, 20K, and 20T are respectively Are connected to a toner cartridge corresponding to the developing device (color) by a toner supply pipe (not shown). Further, when the amount of toner stored in the toner cartridge is low, this toner cartridge may be replaced.

  Hereinafter, although this embodiment is described further in detail based on an Example, this embodiment is not limited to the following Example. “Part” means “part by mass” unless otherwise specified.

[Adjustment of external additives]
-Preparation of external additive 1-
In a nitrogen atmosphere, 150 parts by mass of ethanol, 10.0 parts by mass of tetraethoxysilane, and 6.0 parts by mass of distilled water are placed in a reaction vessel, and 20% ammonia water is used as a catalyst while stirring. 18.0 parts by mass were added dropwise at a dropping rate of 3.0 g / min to form primary particles having a volume average particle size of 0.03 μm.
Then, 2.0 parts by mass of tetraethoxysilane was newly dropped (dropping rate 4 g / min), and then 20% ammonia water was dropped as a catalyst (dropping rate 3.0 g / min), and the temperature was 30 ° C. for 2 hours. Stirring was performed to form secondary particles having a volume average particle size of 0.18 μm.
Then, after concentrating until the liquid volume became half, 400 ml of distilled water was added, and the product was precipitated by a centrifugal sedimentator. After removing the supernatant by decantation, distilled water was added and separation was performed in the same manner by a centrifugal sedimentator. After repeating this several times, the precipitate was freeze-dried with a freeze dryer for 2 days to obtain silica particles as white powder.
The obtained silica particles are hydrophobized with methyltrimethoxysilane as follows. Specifically, 100 parts by mass of methanol as a solvent, 10 parts by mass of silica particles, and 1.0 part by mass of methyltrimethoxysilane are placed in a reaction vessel in a nitrogen atmosphere, and 20 parts as a catalyst are stirred. % Ammonia water (5.0 parts by mass) was added dropwise at a dropping rate of 3.0 g / min, and the mixture was stirred at a temperature of 30 ° C. for 2 hours.
Then, after concentrating until the liquid volume became half, 400 ml of distilled water was added, and the product was precipitated by a centrifugal sedimentator. After removing the supernatant by decantation, distilled water was added and separation was performed in the same manner by a centrifugal sedimentator. After repeating this several times, the precipitate was freeze-dried for 2 days in a freeze dryer to obtain external additive 1.
Table 1 shows the moisture content and A / a of the obtained external additive.

-Preparation of external additive 2 to external additive 5-
Instead of adding 1.0 part by mass of methyltrimethoxysilane, the outside except that 2.0 parts by mass, 1.5 parts by mass, 0.5 parts by mass and 0.3 parts by mass of methyltrimethoxysilane were added respectively. External additive 5 was obtained from external additive 2 in the same manner as additive 1. Table 1 shows the moisture content and A / a of the obtained external additive.

-Preparation of external additive 9 from external additive 6-
Instead of adding 18.0 parts by weight of 20% aqueous ammonia for forming the primary particle size, 10.0 parts by weight, 25.0 parts by weight, 9.0 parts by weight, and 27 parts by weight of 20% aqueous ammonia, respectively. External additive 9 was obtained from external additive 6 in the same manner as external additive 1 except that it was added. Table 1 shows the moisture content and A / a of the obtained external additive.

-Preparation of external additive 10-
An external additive 10 was obtained in the same manner as the external additive 1 except that the hydrophobic treatment was not performed. Table 1 shows the moisture content and A / a of the obtained external additive.

-Preparation of external additive 11-
Except that 20% ammonia water for forming the primary particle diameter was changed to 5.0 parts by mass instead of 18.0 parts by mass, and the dropping rate was changed to 0.3 g / min instead of 3.0 g / min. External additive 11 was obtained in the same manner as additive 1.
Table 1 shows the moisture content and A / a of the obtained external additive.

-Preparation of external additive 12-
In a nitrogen atmosphere, 300 parts by mass of ethanol as a solvent, 10 parts by mass of titanium isopropoxide, and 3 parts by mass of distilled water were placed in a reaction vessel and stirred, and 4 parts by mass of 20% aqueous ammonia as a catalyst. Was dropped at a dropping rate of 3 g / min to form primary particles having a volume average particle size of 0.04 μm.
Then, 2 parts by mass of titanium isopropoxide was added dropwise (dropping rate 4 g / min), 20% ammonia water was added dropwise as a catalyst (dropping rate 3 g / min), and the mixture was stirred at a temperature of 30 ° C. for 2 hours. Secondary particles having a volume average particle size of 0.17 μm were formed.
Then, after concentrating until the liquid volume became half, 400 ml of distilled water was added, and the product was precipitated by a centrifugal sedimentator. After removing the supernatant by decantation, distilled water was added and separation was performed in the same manner by a centrifugal sedimentator. After repeating this several times, the precipitate was freeze-dried with a freeze dryer for 2 days to obtain titania particles as white powder.
The obtained titania particles are hydrophobized with methyltrimethoxysilane as follows. Specifically, 100 parts by mass of methanol as a solvent, 10 parts by mass of titania particles, and 1.0 part by mass of methyltrimethoxysilane were placed in a reaction vessel in a nitrogen atmosphere, and 20 parts as a catalyst were stirred. % Ammonia water (5.0 parts by mass) was added dropwise at a dropping rate of 3.0 g / min, and the mixture was stirred at a temperature of 30 ° C. for 2 hours.
Then, after concentrating until the liquid volume became half, 400 ml of distilled water was added, and the product was precipitated by a centrifugal sedimentator. After removing the supernatant by decantation, distilled water was added and separation was performed in the same manner by a centrifugal sedimentator. After repeating this several times, the precipitate was freeze-dried in a freeze dryer for 2 days to obtain an external additive 12.
Table 1 shows the moisture content and A / a of the obtained external additive.

-Preparation of external additive 13-
Styrene 308 parts by weight n-Butyl acrylate 92 parts by weight Acrylic acid 6 parts by weight Propanediol diacrylate 1.0 part by weight Dodecanethiol 2.7 parts by weight In a solution in which the above components are mixed and dissolved, the anionic surfactant Daupax ( 4 g of Rhodia) was dissolved in 550 g of ion-exchanged water, slowly stirred and mixed for 10 minutes while being dispersed and emulsified in a flask, and then 50 g of ion-exchanged water in which 6 g of ammonium persulfate was dissolved was added. Thereafter, the interior of the system was sufficiently replaced with nitrogen, and then the flask was heated with an oil bath while stirring until the interior became 70 ° C., and emulsion polymerization was continued for 1 hour.
As a result, a resin fine particle dispersion having a central particle size of the resin fine particles of 0.05 μm was obtained. To this dispersion, 1.23 parts by weight of polyaluminum chloride was added, and thoroughly mixed and dispersed with an Ultra Turrax T50 manufactured by IKA.
Thereafter, the product was precipitated by a centrifugal sedimentator. After removing the supernatant by decantation, distilled water was added and separation was performed in the same manner by a centrifugal sedimentator. After repeating this several times, the precipitate was freeze-dried with a freeze dryer for 2 days to obtain an external additive 13 as resin particles.
Table 1 shows the moisture content and A / a of the obtained external additive.

-Preparation of external additive 15 from external additive 14-
20% ammonia water for forming the primary particle size is changed to 5.0 parts by mass instead of 18.0 parts by mass, the dropping rate is changed to 0.3 g / min instead of 3.0 g / min, and methyltrimethoxysilane Was added in the same manner as external additive 1 except that the content was changed to 2.0 parts by mass instead of 1.0 part by mass. Further, the external additive 15 was changed in the same manner as the external additive 1 except that 20% ammonia water for forming the primary particle diameter was changed to 20 parts by mass instead of 18.0 parts by mass and the hydrophobization treatment was not performed. Obtained. Table 1 shows the moisture content and A / a of the obtained external additive.

[Example 1]
<Preparation of Toner 1>
-Preparation of polyester resin (1)-
Dimethyl adipate: 74 parts Dimethyl terephthalate: 192 parts Bisphenol A ethylene oxide adduct: 216 parts Ethylene glycol: 38 parts Tetrabutoxy titanate (catalyst): 0.037 parts

The above components are placed in a heat-dried two-necked flask, and nitrogen gas is introduced into the container and heated while stirring in an inert atmosphere, and then subjected to a copolycondensation reaction at 160 ° C. for 7 hours, and then gradually up to 10 Torr. The temperature was raised to 220 ° C. while reducing the pressure to 4 hours. Once the pressure was returned to normal pressure, 9 parts of trimellitic anhydride was added, and the pressure was gradually reduced again to 10 Torr and maintained at 220 ° C. for 1 hour to synthesize polyester resin (1).
When the molecular weight of the obtained polyester resin (1) was measured using GPC by the above-described measurement method, the weight average molecular weight (Mw) was 12,000 and the number average molecular weight was 4,000.

-Preparation of polyester resin (2)-
-Bisphenol A ethylene oxide 2-mole adduct: 114 parts-Bisphenol A propylene oxide 2-mole adduct: 84 parts-Dimethyl terephthalate: 75 parts-Dodecenyl succinic acid: 19.5 parts-Trimellitic acid: 7.5 parts

The above components were put into a 5 liter flask equipped with a stirrer, a nitrogen inlet tube, a temperature sensor, and a rectifying tower, the temperature was raised to 190 ° C. over 1 hour, and the reaction system was stirred, 3.0 parts of dibutyltin oxide was added. Further, 6 hours were required while distilling off the generated water, the temperature was raised from 190 ° C. to 240 ° C., and the dehydration condensation reaction was continued at 240 ° C. for another 2 hours to synthesize polyester resin (2).
The weight average molecular weight of the obtained polyester resin (2) was 58,000, and the number average molecular weight was 5,600.

-Preparation of polyester resin dispersion (1)-
Polyester resin (1) (Mw: 12,000): 160 parts Ethyl acetate: 233 parts Sodium hydroxide aqueous solution (0.3N): 0.1 parts

  The above components were put into a 1000 ml separable flask, heated at 70 ° C., and stirred by a three-one motor (manufactured by Shinto Kagaku Co., Ltd.) to prepare a resin mixture. While further stirring this resin mixture, 373 parts of ion-exchanged water was gradually added to effect phase inversion emulsification and solvent removal to obtain a polyester resin dispersion (1) (solid content concentration: 30%). The volume average particle size of the resin particles in the dispersion was 160 nm.

-Preparation of polyester resin dispersion (2)-
A polyester resin dispersion (2) (solid content concentration: 30%) was prepared in the same manner as the polyester resin dispersion (1) except that the polyester resin (2) was used instead of the polyester resin (1). The volume average particle size of the resin particles in the dispersion was 160 nm.

-Preparation of release agent particle dispersion-
Paraffin wax (Nippon Seiwa Co., Ltd., HNP-9, melting point: 75 ° C.): 50 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 1.0 part PAC (Polyaluminum chloride, manufactured by Asada Chemical Co., Ltd .: use powder product): 5 parts, ion-exchanged water: 200 parts The above is mixed and heated to 95 ° C., and a homogenizer (manufactured by IKA, Ultra Turrax T50) is used. After being dispersed, a release agent particle dispersion liquid (solid) obtained by dispersing a release agent particle having a volume average particle size of 0.23 μm by performing a dispersion treatment for 360 minutes with a Menton Gorin high-pressure homogenizer (Gorin). Minor concentration: 20%).

-Production of toner particles-
Ion-exchange water: 450 parts by weight Polyester resin dispersion (2): 210 parts by weight Polyester resin dispersion (1): 210 parts by weight Anionic surfactant: 2.8 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen) RK, 20% by mass)
The above components were put into a 3 liter reaction vessel equipped with a thermometer, a pH meter, and a stirrer, and maintained at a temperature of 30 ° C. and a stirring rotation speed of 150 rpm for 30 minutes while controlling the temperature with a mantle heater from the outside. Thereafter, 100 parts by mass of the release agent particle dispersion was added and held for 5 minutes. The 1.0 wt% nitric acid aqueous solution was added as it was, and the pH in the aggregation process was adjusted to 3.0.

While adding 0.4 parts by mass of polyaluminum chloride while dispersing with a homogenizer (IKA Japan Co., Ltd .: Ultra Tarax T50), the temperature was raised to 50 ° C. while stirring, and Coulter Multisizer II (aperture diameter: 50 μm, The particle size was measured by Coulter Co.), and the volume average particle size was 5.5 μm. Thereafter, 110 parts by mass of the polyester resin dispersion (2) and 73 parts by mass of the polyester resin dispersion (1) were added, and the resin particles were adhered to the surface of the aggregated particles.
Thereafter, the pH was adjusted to 9.0 using a 5% by mass aqueous sodium hydroxide solution. Thereafter, the temperature was increased to 90 ° C. at a rate of temperature increase of 0.05 ° C./min, held at 90 ° C. for 3 hours, then cooled and filtered to obtain coarse toner particles. This was further redispersed in ion-exchanged water and filtered, and washed until the electrical conductivity of the filtrate was 20 μS / cm or less, and then vacuum-dried in an oven at 40 ° C. for 5 hours. Thus, toner particles were obtained.

-Adhesion of external additives-
2.5 parts by mass of the external additive 1 was added to 100 parts by mass of the obtained toner particles, and mixed and blended at 10,000 rpm for 30 seconds using a sample mill. Thereafter, toner 1 was prepared by sieving with a vibrating sieve having an opening of 45 μm. The obtained toner had a volume average particle diameter of 6.1 μm. Further, the Al content in the release agent domain of the obtained toner was 0.03 atom%. Table 2 shows the difference (Tm−Tc) between Tm and Tc in the obtained toner.

<Creation of carrier>
・ Toluene 14 parts ・ Styrene-methyl methacrylate copolymer (mass ratio: 80/20, weight average molecular weight: 70000) 2 parts ・ MZ500 (zinc oxide, titanium industry) 0.6 parts The solution for forming a coating layer in which zinc oxide was dispersed by stirring was prepared. Next, this coating solution and 100 parts of ferrite particles (volume average particle size: 38 μm) are put in a vacuum degassing kneader and stirred at 60 ° C. for 30 minutes, and then degassed by further reducing pressure while heating. The carrier was prepared by drying.

<Preparation of electrostatic latent image developer>
The obtained carrier and toner 1 were mixed at a ratio of 100 parts: 8 parts by a 2 liter V blender to prepare an electrostatic latent image developer 1.

<Evaluation>
-Uneven gloss-
The developer thus obtained is filled in the developer of the five-drum tandem type DocuCentre-III C7600 modified machine (five-drum tandem modified machine for double-sided printing) manufactured by Fuji Xerox Co., Ltd. A solid image (18 cm × 27 cm) having a toner loading of 4.5 g / cm ² was formed on both sides of A4 on (OK top coat + paper, manufactured by Oji Paper Co., Ltd.) at a fixing temperature of 190 ° C. With respect to the image portion of the formed solid image, using a gloss meter (BYK micro trigloss gloss meter (20 + 60 + 85 °), manufactured by Gardner), the leading surface of the solid image is 24 points as shown in FIG. 60-degree gloss was measured on the point). The gloss unevenness was evaluated from the difference in glossiness at 24 points (maximum value-minimum value). The evaluation criteria are as follows, and the results are shown in Table 2.

-Evaluation criteria for gloss unevenness-
A: Glossiness difference is less than 5%, and standard deviation of gloss measurement 24 points is 2.5 or less B: Glossiness difference is less than 5% B: Glossiness difference is 5% or more and less than 10%
X: Gloss difference is 10% or more

-Evaluation of adhesion of image area after fixing-
The developer thus obtained is filled in the developer of the five-drum tandem type DocuCentre-III C7600 modified machine (five-drum tandem modified machine for double-sided printing) manufactured by Fuji Xerox Co., Ltd. A solid image (18 cm × 18 cm × ² on toner) on both sides of the A4 sheet (OK top coat + paper, manufactured by Oji Paper Co., Ltd.) at a fixing temperature of 190 ° C. and a process speed of 500 mm / sec. 27 cm) was continuously formed and placed in each case. After the image formation of 200 sheets was completed, the printed material that was overlapped in contact with the 100th printed material was peeled off, the 100th printed material was taken out, and image defects in the image area were visually observed. The evaluation criteria are as follows, and the results are shown in Table 2.

-Evaluation criteria for image adhesion-
○: No image defect.
Δ: A sound is produced when peeling, but there is no image defect.
X: There is an image defect.

-Evaluation of charge reduction in toner-
The developer thus obtained is filled in the developer of the five-drum tandem type DocuCentre-III C7600 modified machine (five-drum tandem modified machine for double-sided printing) manufactured by Fuji Xerox Co., Ltd. A solid image (18 cm × 18 cm × ² on toner) on both sides of the A4 sheet (OK top coat + paper, manufactured by Oji Paper Co., Ltd.) at a fixing temperature of 190 ° C. and a process speed of 500 mm / sec. 27 cm) was continuously formed.
Thereafter, it was visually confirmed whether or not the scattered toner adhered to the periphery of the developing device of the image forming apparatus (specifically, the exposure window). The evaluation criteria are as follows, and the results are shown in Table 2.

-Evaluation criteria for charge reduction-
○: No scattered toner adhered.
(Triangle | delta): Although adhesion of the scattered toner is confirmed slightly, it is the range accept | permitted practically.
X: Adhering of scattered toner is confirmed, and the practically acceptable range is exceeded.

[Example 2 to Example 13]
Toner 13 was obtained from toner 2 in the same manner as toner 1 except that external additive 2 to external additive 13 were used instead of external additive 1 in the preparation of toner. Further, evaluation was performed in the same manner as in Example 1 except that toner 2 to toner 13 were used instead of toner 1. The results are shown in Table 2.

[Example 14]
Toner 14 was obtained in the same manner as Toner 1 except that in the preparation of the release agent particle dispersion, PAC was changed to 1 part instead of 5 parts. The evaluation was performed in the same manner as in Example 1 except that the toner 14 was used instead of the toner 1. The results are shown in Table 2.

[Comparative Example 1 to Comparative Example 2]
Toner 16 was obtained from toner 15 in the same manner as toner 1 except that external additive 14 to external additive 15 were used instead of external additive 1 in the preparation of toner. Further, evaluation was performed in the same manner as in Example 1 except that toner 15 to toner 16 were used instead of toner 1. The results are shown in Table 2.

[Comparative Example 3]
Toner 17 was obtained in the same manner as Toner 1 except that in the preparation of the release agent particle dispersion, PAC was changed to 0.5 parts instead of 5 parts. The evaluation was performed in the same manner as in Example 1 except that toner 17 was used instead of toner 1. The results are shown in Table 2.

  From the above results, it can be seen that in the example, uneven gloss and adhesion of the image portion are suppressed as compared with the comparative example.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a figure which shows the measurement position of the glossiness in an Example.

DESCRIPTION OF SYMBOLS 11 Photoconductor 12 Drive roll 13 Support roll 14 Bias roll 15 Cleaning apparatus 16 Belt cleaner 17 Primary transfer roll 18 Charging roll 19 Exposure apparatus 20 Developing apparatus 34 Secondary transfer roll 35 Fixing device 40 Toner cartridge 50 Image forming unit P Recording paper

Claims (9)

Toner particles containing a binder resin and a release agent having a melting temperature of 60 ° C. or more and 120 or less, and an external additive having a moisture content of 5% by mass or more and 15% by mass or less,
An endothermic peak Tm derived from the release agent in the toner particles in the temperature rising process measured by a differential scanning calorimeter (DSC) based on the ASTM method, and the mold release in the toner particles in the temperature lowering process. A transparent toner for developing an electrostatic latent image, wherein a difference (Tm−Tc) from an exothermic peak Tc derived from the agent is 10 ° C. or more and 50 ° C. or less.   The transparent toner for developing an electrostatic latent image according to claim 1, wherein the external additive has irregularities on a surface thereof. When the BET specific surface area of the external additive is A (m ² / g) and the spherical equivalent specific surface area of the external additive is a (m ² / g), the value of A / a is 1.1 or more and 10. The transparent toner for developing an electrostatic latent image according to claim 1, wherein the toner is 0 or less.
[Here, the spherical equivalent specific surface area a is such that when the volume average particle diameter of the external additive is d (unit: μm) and the true specific gravity of the external additive is ρ (unit: dimensionless), a = 6 / (d × ρ). ]   An electrostatic latent image developer comprising the transparent toner for developing an electrostatic latent image according to any one of claims 1 to 3.   The electrostatic latent image developer according to claim 4, comprising a carrier containing a white conductive agent.   A toner cartridge for storing the electrostatic latent image developing transparent toner according to any one of claims 1 to 3.   A process cartridge comprising a developing device that accommodates the electrostatic latent image developer according to claim 4. A latent image carrier,
Electrostatic latent image forming means for forming an electrostatic latent image on the latent image holding member;
Developing means for developing the electrostatic latent image formed on the latent image holding member as a toner image with the electrostatic latent image developer according to claim 4;
Transfer means for transferring the toner image formed on the latent image holding member to a transfer target;
An image forming apparatus comprising: a fixing unit configured to fix the toner image transferred to the transfer medium.   The image forming apparatus according to claim 8, wherein the process speed is 500 mm / sec or more.