JP6225784B2 - Electrostatic image developing toner, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Description

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

  A method for visualizing image information through an electrostatic charge image by electrophotography or the like is currently used in various fields. In electrophotography, image information is formed as an electrostatic charge image on the surface of an image carrier (photoreceptor) by charging and exposure processes, and a toner image is developed on the surface of the photoreceptor using a developer containing toner. The toner image is visualized as an image through a transfer process for transferring the toner image to a recording medium such as paper and a fixing process for fixing the toner image on the surface of the recording medium.

  For example, Patent Document 1 states that “a toner for electrostatic charge development containing at least a binder resin, a colorant, and two or more release agents, and among the two or more release agents, The density difference between the main mold release agent and the micro mold release agent having a smaller content than the main mold release agent is a value specified by ASTM D792, and is 0.02 or more, An electrostatic charge image developing toner characterized in that the total mixing ratio of trace release agents is 0.1 to 15.0 mass% is disclosed.

Patent Document 2 states that “a toner containing at least a binder resin, a colorant, and a wax, in which the wax content is the mass-converted endothermic amount of the wax determined by a DSC (Differential Scanning Calorimetry) method. And FTIR-ATR (total reflection absorption infrared spectroscopy) as a value defining the amount of the wax existing in the depth region from the surface of the toner particles to 0.3 μm, which is 3 to 21% by mass of the total toner mass. ) obtained by method, the wax-derived peak (intensity ratio of the 2850 cm ^-1) and the binder resin from the peak _{^{(828cm -1) (P 2850 /}} P 828) is in the range of 0.01 to 0.40 And at least a part of the wax is present as a plurality of independent wax dispersion particles encapsulated in the toner particles. It is shown.

JP 2005-265989 A JP 2008-276269 A

  An object of the present invention is to provide an electrostatic charge image developing toner in which adhesion between recording media after toner image fixing is suppressed, and fluctuation in image glossiness is suppressed when continuously output. is there.

  The above problem is solved by the following means.

The invention according to claim 1
Including a binder resin and a release agent,
The binder resin includes a styrene- (meth) acrylic copolymer resin,
The mold release agent includes two or more paraffinic waxes having different melting temperatures,
The total content of the release agent is 3.0% by mass or more and 5.0% by mass or less,
When a cross-sectional image analysis is performed using a scanning transmission electron microscope, 50% by area or more of the release agent displayed in the image has a depth from the outer peripheral portion to a radius of / 2. Exists in the area,
An electrostatic image developing toner satisfying the following (1) and (2) by differential scanning calorimetry.
(1) In the first temperature rise spectrum,
There is a peak P _a ¹ whose endotherm is greater than 2 J / g in absolute value,
Temperature _T ^{a 1} peak top of the peak _P ^{a 1} is at 70 ° C. or higher 100 ° C. or less.
(2) In the temperature drop spectrum from 150 ° C.
A peak P _b ¹ having a peak top in a temperature range of 70 ° C. or more and 92 ° C. or less;
Peak _P ^{b 2} having a peak top at the peak _P ^{when b 1} of the temperature of the peak top was ^{_{T b 1 (T b 1 -20}} ) ℃ or higher ^_(T b 1 -3) ° C. temperature range below,
There is a peak P _b ³ having a peak top in a temperature range of 53 ° C. or more and less than 67 ° C.

The invention according to claim 2
Said peak _P ^{b 2} of the peak height ^{H 2} is, for developing an electrostatic charge image according to the peak _P ^{b 1} higher claims 1 than the peak height ^{H 3} of the peak height ^{H 1} and the peak _P ^{b 3} Toner.

The invention according to claim 3
An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1.

The invention according to claim 4
Containing the toner for developing an electrostatic image according to claim 1;
The toner cartridge is detachable from the image forming apparatus.

The invention according to claim 5
A developing unit that contains the electrostatic charge image developer according to claim 3 and that develops the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer.
It is a process cartridge that can be attached to and detached from the image forming apparatus.

The invention according to claim 6
An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
A developing means for containing the electrostatic charge image developer according to claim 3 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus.

The invention according to claim 7 provides:
A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer according to claim 3;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
Is an image forming method.

According to the first aspect of the invention, compared to the case where the above (1) and (2) are not satisfied in the differential scanning calorimetry, the adhesion between the recording media after fixing the toner image is suppressed, and the output is continuously performed. An electrostatic image developing toner is sometimes provided in which fluctuations in the glossiness of the image are suppressed.
According to the invention of claim 2, in lowering the spectrum from 0.99 ° C. in differential scanning calorimetry, the peak _P ^{b 2} peak height ^{H 2,} the peak _P ^{b 1} peak heights ^{H 1} and peak _P ^{b 3} compared to when the same or lower as the peak height H ³ of the attachment of each other recording medium after the toner image fixing is suppressed, and an electrostatic image to change the glossiness of an image is suppressed when the output continuously A developing toner is provided.

  According to the inventions according to claims 3, 4, 5, 6 and 7, the adhesion of the recording medium after fixing the toner image is suppressed as compared with the case where the above (1) and (2) are not satisfied in the differential scanning calorimetry. In addition, there are provided an electrostatic charge image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method in which fluctuations in glossiness of an image are suppressed when continuously output.

It is an example of the temperature rising spectrum of the 1st time in the differential scanning calorimetry of the toner which concerns on this embodiment. It is an example of the temperature fall spectrum in the differential scanning calorimetry of the toner which concerns on this embodiment. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the process cartridge which concerns on this embodiment. 4 is a temperature drop spectrum from 150 ° C. of differential scanning calorimetry in the toner obtained in Example 1.

  Hereinafter, an embodiment which is an example of the present invention will be described in detail.

<Toner for electrostatic image development>
The electrostatic image developing toner (hereinafter referred to as “toner”) according to the present embodiment includes a binder resin and a release agent. The binder resin includes a styrene- (meth) acrylic copolymer resin, and the release agent includes two or more paraffinic waxes having different melting temperatures.
When the total content of the release agent in the toner is 3.0% by mass or more and 5.0% by mass or less and image analysis of the cross section of the toner is performed with a scanning transmission electron microscope (STEM), Of the total of the displayed release agents, 50% by area or more of the release agent is present in a region having a depth from the outer peripheral portion to radius / 2 (hereinafter also referred to as “surface layer side region”).
Further, the toner satisfies the following (1) and (2) by differential scanning calorimetry (DSC) measurement.

(1) In the first temperature rise spectrum,
There is a peak P _a ¹ whose endotherm is greater than 2 J / g in absolute value,
Temperature _T ^{a 1} peak top of a peak _P ^{a 1} is at 70 ° C. or higher 100 ° C. or less.

(2) In the temperature drop spectrum from 150 ° C.
A peak P _b ¹ having a peak top in a temperature range of 70 ° C. or more and 92 ° C. or less;
Peak _P ^{b 2} having a peak top at ^_(T b 1 -20) ℃ or higher ^_(T b 1 -3) ℃ temperature range below when the temperature of the peak top of the peak _P ^{b 1} was _T ^{b 1,}
There is a peak P _b ³ having a peak top in a temperature range of 53 ° C. or more and less than 67 ° C.

  With the toner according to the present embodiment, the above configuration suppresses adhesion between the recording media after fixing the toner image, and suppresses fluctuations in the glossiness of the image when continuously output. Although this reason is not certain, the reason shown below is estimated.

  In the case of continuous output, the first several sheets after the start of output are output in a state where the fixing means (hereinafter also referred to as a fixing device) is sufficiently warmed, so that the amount of seepage of the release agent is sufficient. On the other hand, after the tens of sheets, the recording medium is deprived of heat, so that the temperature of the fixing device is lowered, the amount of heat given to the toner is reduced, and the amount of the release agent exuded is reduced. On the other hand, when the release amount of the release agent is too large, the release agent attached to the image surface also increases, and the image becomes dull and the glossiness decreases due to the crystallization of the release agent. Since the amount of heat taken by the recording medium differs depending on the type of recording medium, the amount of the release agent in the toner is set so that the amount of the release agent exuded does not become excessive even when the recording medium with the smallest heat absorption is used. Therefore, it is preferable that the amount is smaller than that in the past. Therefore, it is possible to control the crystallization of the release agent adhering to the image surface while stably controlling the amount of the release agent exuded while keeping the release agent content in the toner small. It becomes important.

  When the amount of the release agent oozing out decreases, the amount of the release agent on the image surface formed on the recording medium decreases, and the continuously output recording medium (recorded material) is stacked and stored in the storage container. When it is done, it becomes easy for the recording media to adhere to each other.

  Further, when the amount of the release agent exuded decreases during continuous output, the glossiness of the image also decreases. For this reason, the glossiness of the image tends to fluctuate between the first few sheets at the start of output and the tenth and subsequent sheets.

  Furthermore, the recorded material in the middle of the continuous output is sandwiched between the recorded materials and stored in the storage container, so it is difficult to cool, but the last recorded product in continuous output is stored in the storage container in a state exposed to the outside air. Therefore, the temperature tends to decrease. As described above, in the continuous output, there is a difference in the temperature of the recorded material between the beginning, the middle, and the last, and the crystal state of the release agent changes. For this reason, in continuous output, the glossiness of an image tends to fluctuate. In particular, this phenomenon is likely to occur at a high temperature of 35 ° C. or more, and is likely to occur in an emerging country such as Southeast Asia where an air conditioning facility is insufficient.

On the other hand, in the toner according to the exemplary embodiment, even when the total content of the release agent in the toner is reduced to 3.0% by mass or more and 5.0% by mass or less, styrene- (meth) is used as a binder resin. When an acrylic copolymer resin is used and image analysis of the cross section of the toner is performed with a scanning transmission electron microscope, 50% by area or more of the release agent displayed in the image is on the surface layer side. It is designed so that the amount of the release agent oozing out in the fixed image is sufficient by including it in the region.

  From the viewpoint of further suppressing the adhesion between the recording media after fixing the toner image, it is preferable that a release agent of 70 area% or more exists in the surface layer side region in the toner before fixing, and it is 80 area% or more. More preferably, it is more preferably 90 area% or more. On the other hand, from the viewpoint of suppressing fluctuations in the glossiness of images when output continuously, it is preferable that the amount of the release agent is not present on the image surface, but this is contrary to the suppression of adhesion between recording media. Therefore, this invention was completed by using the combination of the special mold release agent mentioned later.

  The image analysis of the cross section in the scanning transmission electron microscope (STEM) is performed for 500 toners, and the above numerical values are average values. A specific method for image analysis of a toner cross section by a scanning transmission electron microscope (STEM) is as follows.

First, a toner to be measured is embedded in an epoxy resin, and then the epoxy resin is solidified. This solidified product is sectioned to a thickness of 100 nm by a microtome. After the toner cross section of the section is ruthenium-stained with a 0.5% by weight aqueous solution of ruthenium tetroxide, a STEM image of the toner cross section is obtained with a scanning transmission electron microscope (STEM). In the STEM image, the part that appears white is the release agent. The total area S of the release agent is calculated by analyzing the obtained STEM image. Further, the area S1 of the release agent existing in the depth range from the outer peripheral portion of the toner to the radius / 2 is calculated. Then, the ratio (%) of the area S1 to the total area S is calculated.

Also, in one round of heating spectrum in differential scanning calorimetry, an endothermic amount is present a large peak P _a ¹ than 2J / g in absolute value, the temperature T _a ¹ peak top of a peak P _a ¹ is 70 ° C. The toner is designed to be surely fixed by using the toner having a temperature of 100 ° C. or lower.

Then, two or more paraffinic waxes having different melting temperatures are contained in the toner as a release agent, and in the temperature drop spectrum from 150 ° C. in differential scanning calorimetry, the following three peaks P _b ¹ , P _b ² , and By using a toner having P _b ³ , the amount of release agent exuded and the temperature dependency of crystallization are reduced.

Peak P _b ¹ has a peak top within a temperature range of 70 ° C. or more and 92 ° C. or less.
Peak P _b ² : When the temperature of the peak top of peak P _b ¹ is T _b ¹ , it has a peak top within a temperature range of (T _b ¹ −20) ° C. to (T _b ¹ −3) ° C. .
Peak P _b ³ : has a peak top in a temperature range of 53 ° C. or higher and lower than 67 ° C.

The peak P _b ¹ is an exothermic peak derived from the paraffinic wax on the high melting temperature side among the two or more paraffinic waxes.
The peak P _b ² is an exothermic peak derived from the interaction between the high melting temperature side paraffinic wax and the low melting temperature side paraffinic wax.
The peak P _b ³ is an exothermic peak derived from the interaction between the paraffinic wax on the low melting temperature side and the binder resin.

Due to the presence of the component contributing to the peak P _b ² , the crystallization of the release agent on the low melting temperature side occurs with the crystallization of the release agent on the high melting temperature side. Due to the presence of the component contributing to the peak P _b ¹ , the release agent can be recrystallized quickly after fixing. Due to the presence of the component contributing to peak P _b ³ , the release agent can be slowly recrystallized after fixing. As a result, the crystallization speed is made constant regardless of the temperature history, the variation of the release amount of the release agent is suppressed, and as a result, the adhesion of the recording media after fixing the toner image is suppressed, and the output is continuously performed. It is estimated that the fluctuation of the glossiness of the image is suppressed when

  Differential scanning calorimetry is performed according to ASTM D3418-8. First, a toner to be measured is set in a differential scanning calorimeter (for example, device name: DSC-60 manufactured by Shimadzu Corporation) equipped with an automatic tangential processing system, and a room temperature (for example, 10 ° C./min) 25 ° C.) to 150 ° C. to obtain the first temperature increase spectrum. After maintaining at 150 ° C. for 5 minutes, the temperature is lowered from 150 ° C. to 0 ° C. at a temperature decreasing rate of 10 ° C./min, and a temperature decrease spectrum is obtained.

FIG. 1 shows an example of the first temperature rise spectrum. For the endothermic peak P _a ¹ based on melting of the release agent, the temperature at the peak top D is determined as T _a ¹ . The endothermic amount is obtained from the area of the rising portion from the baseline (the portion surrounded by connecting A and B).

FIG. 2 shows an example of the temperature drop spectrum. In the temperature drop spectrum, the temperatures at the respective peak tops D ¹ , D ^2, and D ³ are determined as T _b ¹ , T _b ^2, and T _b ³ for the three endothermic peaks P _b ¹ , P _b ^2, and P _b ³ .

In cooling spectrum, endothermic peaks _P ^{b 1} and _P ^{b 3} is spectrum buried the endothermic peak _P ^{b 2,} but may appear as a shoulder of an endothermic peak _P ^{b 2,} also in this case referred to as an endothermic peak. In addition, the endothermic peak in the temperature drop spectrum means that the displacement from the baseline exceeds the noise level, and specifically means that the displacement from the baseline exceeds 100% of the noise width. For example, in the endothermic peak P _b ³ of FIG. 2, the displacement from the baseline XY exceeds 100% of the noise width.

The endothermic amount of the peak P _a ¹ is larger than 2 J / g in absolute value, and is preferably 2.5 J / g or more, more preferably 3.0 J / g or more from the viewpoint of improving the fixability. . Further, from the viewpoint of suppressing the release amount of the release agent on the recording medium having a small endothermic amount, the endothermic amount of the peak P _a ¹ is preferably 15 J / g or less in absolute value, and preferably 10 J / g or less. Is more preferable, and it is still more preferable that it is 8 J / g or less.

The peak top temperature T _a ¹ of the peak P _a ¹ is in the temperature range of 70 ° C. or higher and 100 ° C. or lower, preferably 73 ° C. or higher and 93 ° C. or lower, more preferably 74 ° C. or higher and 78 ° C. or lower. preferable.

Peak top D ¹ of the peak P _b ¹ is in the temperature range of 70 ° C. or higher 92 ° C. or less, preferably within a temperature range of 80 ° C. or higher 90 ° C. or less, 83 ° C. or higher 87 ° C. in a temperature range of More preferably.

The peak top D ² of the peak P _b ² is preferably in the temperature range of 65 ° C. or higher and 85 ° C. or lower, more preferably in the temperature range of 69 ° C. or higher and 81 ° C. or lower, and 70 ° C. or higher and 73 ° C. or lower. More preferably, it is in the temperature range.

The peak top D ³ of the peak P _b ³ is in the temperature range of 53 ° C. or more and less than 67 ° C., preferably in the temperature range of 57 ° C. or more and 63 ° C. or less, and in the temperature range of 57 ° C. or more and 61 ° C. or less. More preferably.

From the standpoint that the crystallization rate is constant regardless of the temperature history and the fluctuation of the release amount of the release agent is suppressed, of the peak heights of the peaks P _b ¹ , the peak P _b ² and the peak P _b ³ , the peak P it is preferred that the peak heights of _b ² is the highest.

Peak height ^{H 1} of the peak _P ^{b 1} to the peak height ^{H 2} of the peak _P ^{b 2} is more able to be at 1/20 or more 18/20 or less preferably, 1/10 or more 5/10 or less preferable.

Further possible, peak height ^{H 3} of the peak _P ^{b 3} to the peak height ^{H 2} of the peak _P ^{b 2} is preferably from 1/10 or more 9/10 is 2/10 or 8/10 or less Is more preferably 3/10 or more and 7/10 or less.

The peak height is the distance from the baseline to the peak top at each peak. For example, at the endothermic peak P _b ¹ in FIG. 2, the distance from the baseline XY to the peak top D ¹ is measured, and this is defined as the peak height H ¹ of the endothermic peak P _b ¹ .

  The toner exhibiting the above spectrum in the differential scanning calorimetry is obtained by, for example, the following methods (1) to (3).

(1) Two or more release agents having different melting temperatures are added and cured at a temperature of −8 ° C. to + 4 ° C. for an appropriate time with respect to the melting temperature of the release agent on the high melting temperature side.
(2) Toner particles having a core / shell structure, the core contains a release agent on the low melting temperature side, and the shell contains a release agent on the high melting temperature side.
(3) Manufactured by agglomeration coalescence method, and when the temperature is lowered after the coalescence is completed, the temperature lowering rate in the range from coalescence temperature to coalescence temperature -5 ° C is -5 ° C / 15 minutes or more to -5 ° C / 1 minute. Control within the following range.

By the above method, the release agent on the low melting temperature side grows as a crystal nucleus using the release agent on the high melting temperature side as a crystal nucleus, and becomes a component contributing to the peak P _b ² . And the component derived from the mold release agent on the high melting temperature side appears as a peak P _b ¹ , and the component derived from the mold release agent on the low melting temperature side appears as a peak P _b ³ .

  Hereinafter, details of the toner according to the exemplary embodiment will be described. Specifically, the toner according to the exemplary embodiment includes toner particles, and may include an external additive as necessary.

(Toner particles)
The toner particles include a binder resin and a release agent. The toner particles may contain other additives as required.

-Binder resin-
As the binder resin, a styrene- (meth) acrylic copolymer resin is used. The polymerizable monomer constituting the styrene- (meth) acrylic copolymer resin will be described below.

  Examples of styrene monomers include styrene, α-methyl styrene, vinyl naphthalene, 2-methyl styrene, 3-methyl styrene, 4-methyl styrene, 2-ethyl styrene, 3-ethyl styrene, 4-ethyl styrene, and the like. Examples include alkyl-substituted styrene having an alkyl chain, halogen-substituted styrene such as 2-chlorostyrene, 3-chlorostyrene, and 4-chlorostyrene, and fluorine-substituted styrene such as 4-fluorostyrene and 2,5-difluorostyrene. Styrene is preferred as the styrene monomer. A styrene-type monomer may be used individually by 1 type, and may use 2 or more types together.

  Examples of (meth) acrylic monomers include (meth) acrylic acid ester monomers, such as (meth) acrylic acid n-methyl, (meth) acrylic acid n-ethyl, and (meth) acrylic acid. n-propyl, n-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, ( N-decyl (meth) acrylate, n-dodecyl (meth) acrylate, n-lauryl (meth) acrylate, n-tetradecyl (meth) acrylate, n-hexadecyl (meth) acrylate, n (meth) acrylate -Octadecyl, isopropyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, isopentyl (meth) acrylate, ( T) amyl acrylate, neopentyl (meth) acrylate, isohexyl (meth) acrylate, isoheptyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenyl (meth) acrylate, (Meth) acrylic acid biphenyl, (meth) acrylic acid diphenylethyl, (meth) acrylic acid t-butylphenyl, (meth) acrylic acid terphenyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid t-butylcyclohexyl, Dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, methoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, β-carboxyethyl (meth) acrylate, (meth) acrylonitrile, (Meth) acrylic Examples include amides. (Meth) acrylic monomers may be used alone or in combination of two or more. As the (meth) acrylic acid ester monomer, n-butyl acrylate is preferable.

  The mixing ratio of the styrene monomer and the (meth) acrylic acid ester monomer is not particularly limited. For example, the styrene monomer is 60 parts by mass or more and 90 parts by mass or less, and the (meth) acrylic acid ester. The example which mix | blends a system monomer with 10 to 40 mass parts is given.

  A chain transfer agent can be used for the binder resin during the polymerization. There is no restriction | limiting in particular as a chain transfer agent, The compound which has a thiol component can be used. Specifically, alkyl mercaptans such as hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, and dodecyl mercaptan are preferred, and in particular, the molecular weight distribution is narrow, so that the storage stability of the toner at high temperature is improved. preferable.

A crosslinking agent may be added to the binder resin as necessary. The cross-linking agent is typically a polyfunctional monomer having two or more ethylenically unsaturated groups in the molecule.
Specific examples of such cross-linking agents include aromatic polyvinyl compounds such as divinylbenzene and divinylnaphthalene; divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesate / trivinyl, naphthalene dicarboxylate Polyvinyl esters of aromatic polyvalent carboxylic acids such as divinyl acid and diphenyl biphenyl carboxylate; Divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridine dicarboxylate; Vinyl pyromutate, vinyl furan carboxylate, pyrrole-2- Vinyl esters of unsaturated heterocyclic compounds such as vinyl carboxylate and vinyl thiophenecarboxylate; butanediol methacrylate, hexanediol acrylate, octanediol methacrylate, decanediol acrylate (Meth) acrylic acid esters of linear polyhydric alcohols such as dodecanediol methacrylate; branches such as neopentylglycol dimethacrylate and 2-hydroxy-1,3-diacryloxypropane; ) Acrylic acid esters; Polyethylene glycol di (meth) acrylate, Polypropylene polyethylene glycol di (meth) acrylates; Divinyl succinate, divinyl fumarate, vinyl / divinyl maleate, divinyl diglycolate, vinyl / divinyl itaconate, acetone Divinyl dicarboxylate, divinyl glutarate, divinyl 3,3′-thiodipropionate, trans-aconite divinyl / trivinyl, divinyl adipate, divinyl pimelate, divinyl suberate, dibi azelate Le, sebacate, divinyl dodecanedioate divinyl, the polyvinyl esters of polycarboxylic acids such as oxalic acid divinyl and the like.
The content of the crosslinking agent is preferably in the range of 0.05% by mass or more and 5% by mass or less, more preferably in the range of 0.1% by mass or more and 1.0% by mass or less of the total amount of the polymerizable monomers.

  The weight average molecular weight (Mw) of the binder resin is preferably from 5,000 to 1,000,000, more preferably from 7,000 to 500,000. The number average molecular weight (Mn) of the binder resin is preferably 2000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the binder resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 10 or less.

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

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

  The binder resin is obtained by a known manufacturing method. For example, a latex obtained by dispersing and stabilizing a copolymer obtained by polymerizing a styrene monomer, a (meth) acrylic acid ester monomer, and, if necessary, other monomers with a surfactant. Can be preferably used as a binder resin component.

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

-Release agent-
As the release agent, two or more paraffin waxes having different melting temperatures are used. As for any mold release agent, it is preferable that melting | fusing temperature is 50 to 110 degreeC, and 60 to 100 degreeC is more preferable.
The melting temperature is determined from the “melting peak temperature” described in the method for determining the melting temperature in JIS K-1987 “Method for measuring the transition temperature of plastics” from the DSC curve obtained by differential scanning calorimetry (DSC).

Moreover, it is preferable that the melting temperature difference of two types of mold release agents is 15 degreeC or more and less than 30 degreeC. The melting temperature of the release agent having a low melting temperature is preferably 60 ° C. or higher and 92 ° C. or lower, and more preferably 67 ° C. or higher and 76 ° C. or lower.

  The mass ratio of the release agent having a low melting temperature and the release agent having a high melting temperature (the release agent having a low melting temperature / the release agent having a high melting temperature) is preferably from 90/10 to 20/80, / 20 or more and 50/50 or less is more preferable, and 80/20 or more and 60/40 or less is still more preferable.

  The total content of the release agent is 3.0% by mass or more and 5.0% by mass or less, and preferably 3.5% by mass or more and 5.0% by mass or less, based on the whole toner particles, and 4.0% by mass. % To 5.0% by mass is more preferable. When the content of the release agent is 3.0% by mass or more, adhesion between the recording media after fixing the toner image is suppressed. When the content of the release agent is 5.0% by mass or less, it is possible to suppress the total amount of the release agent oozing out on a recording medium having a small endothermic amount.

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

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

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

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

-Toner particle characteristics-
The toner particles may be toner particles having a single layer structure, or toner particles having a so-called core / shell structure composed of a core (core particle) and a coating layer (shell layer) covering the core. May be.
Here, the core-shell structure toner particles include, for example, a binder resin and a release agent, and a core portion further including a colorant and other additives as necessary, and a binder resin and a release agent. And a coating layer configured to contain an agent.

  The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

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

  The shape factor SF1 of the toner particles is preferably 110 or more and 150 or less, and more preferably 120 or more and 140 or less.

The shape factor SF1 is obtained by the following formula.
Formula: SF1 = (ML ² / A) × (π / 4) × 100
In the above formula, ML represents the absolute maximum length of the toner, and A represents the projected area of the toner.
Specifically, the shape factor 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. That is, by capturing an optical microscope image of particles dispersed on the surface of a slide glass into a Luzex image analyzer using a video camera, obtaining the maximum length and projected area of 100 particles, calculating by the above formula, and obtaining the average value can get.

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

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

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

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

<Toner production method>
Next, a toner manufacturing method according to this embodiment will be described.
The toner according to the exemplary embodiment can be obtained by externally adding an external additive to the toner particles after the toner particles are manufactured.

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

Specifically, a step of preparing each dispersion (dispersion preparation step),
A first resin particle dispersion in which first resin particles serving as a binder resin are dispersed; a colorant particle dispersion in which colorant particles (hereinafter also referred to as “colorant particles”) are dispersed; Of the release agent particles (hereinafter also referred to as “release agent particles”), a first release agent in which release agent particles on the low melting temperature side (for example, release agent particles having a melting temperature of 70 ° C. or less) are dispersed. Mixing the agent particle dispersion, and aggregating each particle in the mixture dispersion to form first aggregated particles (first aggregated particle forming step);
After obtaining the first aggregated particle dispersion in which the first aggregated particles are dispersed, the first aggregated particle dispersion, the second resin particle dispersion in which the second resin particles serving as the binder resin are dispersed, and two types Among the above release agent particles, a second release agent particle dispersion liquid in which release agent particles on the high melting temperature side (for example, release agent particles having a melting temperature of 90 ° C. or higher) are dispersed is mixed, and the first release agent particles are mixed. A step of forming the second aggregated particles by aggregating so that the second resin particles and the release agent particles on the high melting temperature side further adhere to the surface of the aggregated particles (second aggregated particle forming step);
Heating the second agglomerated particle dispersion in which the second agglomerated particles are dispersed, fusing and coalescing the second agglomerated particles to form toner particles (fusing and coalescing step);
Through this process, it is preferable to produce toner particles.

  Details of each step will be described below.

-Each dispersion preparation process-
First, it prepares with each dispersion liquid used by the aggregation coalescence method. Specifically, among the first resin particle dispersion in which the first resin particles serving as the binder resin are dispersed, the colorant particle dispersion in which the colorant particles are dispersed, and two or more kinds of release agent particles A first release agent particle dispersion in which release agent particles on the low melting temperature side are dispersed, a second resin particle dispersion in which second resin particles are dispersed, and two or more release agent particles A second release agent particle dispersion in which release agent particles on the high melting temperature side are dispersed is prepared.
In each dispersion preparation step, the first resin particles and the second resin particles are referred to as “resin particles”, and the first release agent particles and the second release agent particles are referred to as “release agent particles”. I will explain.

  The resin particle dispersion used in the aggregation and coalescence method is formed from a thermoplastic polymer to be a binder resin, for example, styrenes such as styrene, parachlorostyrene, α-methylstyrene, Vinyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc. Group-containing esters, vinyl nitriles such as acrylonitrile and methacrylonitrile, vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone, ethylene, propylene Homopolymers such as polyolefins such as ethylene and butadiene, copolymers obtained by combining two or more of these, or a mixture thereof, as well as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins And the like, non-vinyl condensation resins, mixtures of these with the vinyl resins, and graft polymers obtained when the vinyl monomers are polymerized in the presence of these polymers. These resins may be used alone or in combination of two or more. Among these resins, vinyl resins are particularly preferable. The vinyl resin is advantageous in that a resin fine particle dispersion can be easily prepared by emulsion polymerization or seed polymerization using an ionic surfactant or the like.

  The method for preparing the dispersion of resin particles is not particularly limited, and a method appropriately selected according to the purpose can be adopted. For example, it can be prepared as follows.

  When the resin in the resin particles is a homopolymer or copolymer (vinyl resin) of a vinyl monomer such as the ester having a vinyl group, the vinyl nitrile, the vinyl ether, or the vinyl ketone. The resin monomer particles made of a vinyl monomer homopolymer or copolymer (vinyl resin) are obtained by emulsion polymerization or seed polymerization of the vinyl monomer in an ionic surfactant. A dispersion obtained by dispersing in an ionic surfactant can be prepared. When the resin in the resin particles is a resin other than a homopolymer or copolymer of the vinyl monomer, the resin can be dissolved in an oily solvent having a relatively low solubility in water. The resin is dissolved in the oily solvent, and the dissolved product is added to water together with the ionic surfactant and the polymer electrolyte, and fine particles are dispersed using a dispersing machine such as a homogenizer, and then heated or decompressed. Thus, it can be prepared by evaporating the oily solvent.

  When the resin particles dispersed in the resin particle dispersion are composite particles containing components other than the resin particles, the dispersion in which these composite particles are dispersed is prepared, for example, as follows. Can do. For example, each component of the composite particles is dissolved and dispersed in a solvent, and then dispersed in water together with an appropriate dispersant as described above, and the solvent is removed by heating or decompression, emulsion polymerization, It can be prepared by a method of immobilizing by performing mechanical shearing or electroadsorption on the latex surface prepared by seed polymerization.

  The center diameter (median diameter) of the resin particles is 1 μm or less, preferably 50 to 400 nm, more preferably 70 to 350 nm. When the average particle size of the resin particles is large, the particle size distribution of the finally obtained toner for developing an electrostatic charge image is broadened, or free particles are generated, leading to a decrease in performance and reliability. On the other hand, if it is too small, the solution viscosity at the time of toner production becomes high, and the particle size distribution of the finally obtained toner may become wide. When the average particle diameter of the resin particles is within the above range, the above disadvantages are eliminated, the uneven distribution between the toners is reduced, the dispersion in the toner is good, and the variation in performance and reliability is advantageous. is there. The average particle size of the resin particles can be measured by, for example, a Doppler scattering type particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Microtrac UPA9340).

  As content of the resin particle contained in a resin particle dispersion liquid, 5 mass% or more and 50 mass% or less are preferable, for example, and 30 mass% or more and 45 mass% or less are more preferable.

  The release agent is dispersed in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid or a polymer base, heated to a temperature higher than the melting point, and has a strong shearing ability and a pressure discharge type disperser (Gorin homogenizer, manufactured by Gorin Co., Ltd.) can be dispersed in the form of fine particles to prepare a dispersion.

  The release agent dispersion liquid preferably has a dispersion average particle diameter D50 of 180 to 350 nm, and more preferably 200 to 300 nm. Moreover, it is preferable that the coarse powder of 600 nm or more does not exist. If the dispersed particle size is too small, the release of the release agent during fixing may be insufficient and the hot offset temperature may be lowered.If the dispersed particle size is too large, the release agent is exposed on the toner surface and the powder characteristics are deteriorated. It may worsen or cause photoconductor filming. In addition, if there is a coarse powder, it is difficult to incorporate the coarse powder into the toner by the wet manufacturing method, so that it becomes a free release agent and may contaminate the developing sleeve and the photoreceptor. The dispersed particle size can be measured with a Doppler scattering type particle size distribution analyzer (manufactured by Nikkiso Co., Ltd., Microtrac UPA9340).

  The method for preparing the colorant dispersion is not particularly limited. For example, media such as a rotary shearing homogenizer (Ultra Turrax (manufactured by IKA) or Milder V (manufactured by Taiheiyo Kiko)), pole mill, sand mill, dyno mill, etc. Examples thereof include a method using a dispersion apparatus such as a dispersion disperser, an ultrasonic disperser, and a high-pressure impact disperser. Which disperser is used can be appropriately selected according to the type of the colorant. In order to narrow the particle size distribution of the dispersion, it is also preferable to perform the production process of the colorant dispersion in two stages. Specifically, in the first step, a media-type disperser (for example, Dynomill), a rotary shear type homogenizer (for example, Ultra Turrax (manufactured by IKA) or Milder V, which has excellent ability to break up coarse powder in the first step. (Manufactured by Taiheiyo Kiko Co., Ltd.), etc., to change the media size and generator (blade) combination of these devices according to the cohesive strength of the colorant, crush the coarse powder, In step 2, the dispersion particle size D50 is dispersed to 50 nm or more and 300 nm or less using a high-pressure impact disperser such as an ultimateizer (manufactured by Sugino Machine).

  If the dispersed particle size is too small, the ratio of the surface area to the colorant volume increases, so that the dispersant is insufficient, and the storage stability of the colorant dispersion is reduced, or it is mixed with other raw materials during toner production. Abnormal aggregation may occur due to shock. On the other hand, it is known that if the dispersed particle size is too large, the transparency and color developability of the toner are impaired. The dispersed particle size can be measured with a Doppler scattering type particle size distribution analyzer (manufactured by Nikkiso Co., Ltd., Microtrac UPA9340).

  In the colorant dispersion, the colorant aggregated particles having a particle size of 500 nm to 800 nm are preferably 3% by number or less. When there are many coarse powders, when producing a toner by the emulsion polymerization aggregation method described later, the particle size distribution of the toner may be broadened or free particles may be easily generated, which may lead to a decrease in performance and reliability. Such coarse powder can be calculated by analyzing an image observed by a transmission electron microscope (TEM) after drying the dispersion and using an image processing apparatus.

-First aggregated particle forming step-
Next, the colorant particle dispersion and the first release agent particle dispersion are mixed together with the first resin particle dispersion.
Then, in the mixed dispersion, the first resin particles, the colorant particles, and the first release agent particles are hetero-aggregated, and the first resin particles and the colorant particles have a diameter close to the diameter of the target toner particles. First aggregated particles including the first release agent particles are formed.

Specifically, for example, the flocculant is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to acidic (for example, the pH is 2 or more and 4 or less), and a dispersion stabilizer is added as necessary. The first resin particles are heated to a glass transition temperature (specifically, for example, the glass transition temperature of the first resin particles −15 ° C. or higher and the glass transition temperature + 10 ° C. or lower). Aggregate to form first aggregated particles.
In the first agglomerated particle forming step, for example, the flocculant is added at room temperature (for example, 25 ° C.) while stirring the mixed dispersion with a rotary shearing homogenizer, and the pH of the mixed dispersion is acidic (for example, pH is 2 or more). 4 or less) and, if necessary, after adding a dispersion stabilizer, the heating may be performed.

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

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

-Second aggregated particle forming step-
Next, the first aggregated particle dispersion in which the obtained first aggregated particles are dispersed, the second resin particle dispersion, and the second release agent particle dispersion are mixed. Note that the present invention is not limited thereto, and for example, the first aggregated particle dispersion and a mixed dispersion in which the second resin particles and the second release agent particles are dispersed in advance may be mixed.
Here, as the dispersion in which the second resin particles and the second release agent particles are dispersed, for example, a second resin particle dispersion and a second release agent particle dispersion are prepared, and each dispersion is prepared. Is obtained by mixing. The second resin particles may be the same type as the first resin particles or different types.

  Then, in the mixed dispersion liquid in which the first aggregated particles, the second resin particles, and the second release agent particles are dispersed, the second resin particles and the second release agent particles adhere to the surface of the first aggregated particles. Thus, the second aggregated particles in which the second resin particles and the second release agent particles are adhered to the surface of the first aggregated particles are formed.

Specifically, for example, in the first aggregated particle forming step, when the first aggregated particle reaches a target particle size, the second resin particle dispersion and the second release agent are added to the first aggregated particle dispersion. The agent particle dispersion is mixed, and the mixture dispersion is heated at a glass transition temperature of −15 ° C. to a glass transition temperature of + 10 ° C. of the second resin particles.
Then, the progress of aggregation is stopped by setting the pH of the mixed dispersion to a range of, for example, about 5.0 or more and 8.5 or less.

  Thereby, the 2nd aggregated particle aggregated so that the 2nd resin particle and the 2nd mold release agent particle may adhere to the surface of the 1st aggregated particle is obtained.

-Fusion / unification process-
Next, with respect to the second aggregated particle dispersion in which the second aggregated particles are dispersed, for example, the glass transition temperature of the first and second resin particles is higher than the glass transition temperature (for example, 25 from the glass transition temperature of the first and second resin particles). The second aggregated particles are fused and coalesced to form toner particles.

  Here, the heating at the time of fusing / merging is not less than the glass transition temperature of the first and second resin particles, and is −8 ° C. to + 4 ° C. with respect to the melting temperature of the release agent particles on the high melting temperature side. It should be temperature. The curing time is preferably 1 hour or more and 5 hours or less, for example. Through the above steps, toner particles are obtained.

  By the above curing, the release agent particles on the low melting temperature side present on the center part side of the second aggregated particles (toner particles) are melted and moved to the surface layer part side of the second aggregated particles (toner particles). It is thought that it gathers around the release agent particles on the high melting temperature side that are not completely melted on the surface layer side. Then, when cooled, it is considered that the release agent particles on the low melting temperature side are crystal-grown using the release agent particles on the high melting temperature side which are not completely melted as crystal nuclei.

  Moreover, it is good to adjust the cooling rate after completion | finish of coalescence. In particular, the range from the coalescence temperature to the coalescence temperature of -5 ° C is controlled to a range of -5 ° C / 15 minutes or more and -5 ° C / 1 minute or less.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

FIG. 3 is a schematic configuration diagram illustrating the image forming apparatus according to the present embodiment.
The image forming apparatus shown in FIG. 3 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming units (hereinafter sometimes simply referred to as “units”) 10Y, 10M, 10C, and 10K are arranged in parallel at a predetermined distance from each other in the horizontal direction. The units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the image forming apparatus.

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

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

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

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

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

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

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

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

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

  Thereafter, the recording paper P is fed into the pressure contact portions (nip portions) of a pair of fixing rolls in a fixing device (an example of a fixing unit) 28, and the toner image is fixed on the recording paper P to form a fixed image.

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

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

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

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

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

FIG. 4 is a schematic configuration diagram showing a process cartridge according to the present embodiment.
The process cartridge 200 shown in FIG. 4 is provided around the photosensitive member 107 and the photosensitive member 107 by, for example, a housing 117 provided with an attachment rail 116 and an opening 118 for exposure. A charging roller 108 (an example of a charging unit), a developing device 111 (an example of a developing unit), and a photoconductor cleaning device 113 (an example of a cleaning unit) are integrally combined and held to form a cartridge. Yes.
In FIG. 4, 109 is an exposure device (an example of an electrostatic charge image forming unit), 112 is a transfer device (an example of a transfer unit), 115 is a fixing device (an example of a fixing unit), and 300 is a recording paper (a recording medium). An example).

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

  The image forming apparatus shown in FIG. 3 is an image forming apparatus having a configuration in which the toner cartridges 8Y, 8M, 8C, and 8K are attached to and detached from each other. The developing devices 4Y, 4M, 4C, and 4K are the developing devices (colors). And a toner supply pipe (not shown). Further, when the amount of toner stored in the toner cartridge becomes low, the toner cartridge is replaced.

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

<Preparation of resin particle dispersion>
(Oil layer 1)
-Styrene (Wako Pure Chemical Industries): 15.3 parts-n-butyl acrylate (Wako Pure Chemical Industries): 4.6 parts-β-carboethyl acrylate (Rhodia Nikka): 0.6 parts-Dodecanethiol (Wako Pure Chemical Industries) Medicinal product): 0.2 parts

(Oil layer 2)
-Styrene (Wako Pure Chemical Industries): 15.3 parts-n-butyl acrylate (Wako Pure Chemical Industries): 4.6 parts-β-carboethyl acrylate (Rhodia Nikka): 0.6 parts-Dodecanethiol (Wako Pure Chemical Industries) Medicinal product): 0.4 parts

(Water layer 1)
-Ion exchange water: 17.5 parts-Anionic surfactant (manufactured by Rhodia): 0.35 parts

(Water layer 2)
・ Ion-exchanged water: 40 parts ・ Anionic surfactant (manufactured by Rhodia): 0.05 part ・ Ammonium persulfate (manufactured by Wako Pure Chemical Industries): 0.3 part

  Half of the components described in the oil layer 1 and the water layer 1 are placed in a flask and mixed by stirring to prepare a monomer emulsified dispersion 1. Similarly, half of the oil layer 2 and the remaining water layer 1 are mixed. A monomer emulsified dispersion 2 was prepared by stirring and mixing. The components of the aqueous layer 2 were put into a reaction vessel, and the inside of the vessel was sufficiently substituted with nitrogen and stirred, and then heated in an oil bath until the temperature in the reaction system reached 75 ° C. First, the monomer emulsion dispersion 1 was dropped into the reaction vessel over 2 hours, and then the monomer emulsion dispersion 2 was dropped over 1 hour to carry out emulsion polymerization. After completion of the dropwise addition, the polymerization was further continued at 75 ° C., and the polymerization was terminated after 3 hours.

  The obtained resin fine particle dispersion was 290 nm when the number average particle diameter D50 of the resin fine particles was measured with a laser diffraction particle size distribution measuring device (LA-700, manufactured by Horiba, Ltd.). A differential scanning calorimeter (Shimadzu Works) DSC-50) was used, and the glass transition point of the resin was measured at a heating rate of 10 ° C./min. It was 52 ° C., and a gel permeation chromatography molecular weight measuring instrument (HLC-8020, manufactured by Tosoh Corporation) was used. Using THF as a solvent, the number average molecular weight (in terms of polystyrene) was measured and found to be 12,000 and the weight average molecular weight was 32,000.

Thereafter, ion-exchanged water was added to adjust the solid content concentration in the dispersion to 40%. Solid concentration, weighed a dispersion of 3 g, 130 ° C., then heated for 30 minutes water was volatilized by, was calculated from the mass of dry matter remaining.

<Preparation of colorant particle dispersion>
Carbon black R330 (Cabot): 200 parts Anionic surfactant (Daiichi Kogyo Seiyaku, Neogen R): 1.5 parts Ion-exchanged water: 800 parts

  Put 28 parts of ion-exchanged water and 2 parts of an anionic surfactant in a stainless steel container whose liquid level is about 1/3 of the container height when all of the above ingredients are added. After sufficiently dissolving the surfactant, all of the pigment was added, and the mixture was stirred using a stirrer until there was no wet pigment, and the foam was sufficiently degassed. After defoaming, the remaining ion-exchanged water was added and dispersed using a homogenizer (manufactured by LKA, Ultra Tarrax T50) at 5000 rpm for 10 minutes, and then stirred for one day with a stirrer for defoaming. After defoaming, the mixture was dispersed again at 6000 rpm for 12 minutes using a homogenizer, and then defoamed by stirring for one day with a stirrer. Subsequently, the dispersion liquid was dispersed at a pressure of 240 MPa using a high-pressure impact disperser ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006). Dispersion was performed for 30 passes in terms of the total liquid amount and the processing capacity of the apparatus.

The resulting dispersion was collected supernatant after standing for 72 hours, by adding ion exchange water to adjust the solid content concentration to 15 mass%. The average particle diameter D50 of the obtained colorant dispersion was 120 nm. As the average particle diameter D50 of the dispersion, an average value of three measurement values excluding the maximum value and the minimum value out of five times measured by Microtrack was used.

<Preparation of release agent particle dispersion>
(Preparation of release agent particle dispersion 1)
-Paraffin wax HNP9 (manufactured by Nippon Seiwa Co., Ltd., melting temperature = 75 ° C): 500 parts-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 25 parts-Ion-exchanged water: 1700 parts

  The above components are heated to 110 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), then dispersed with a Manton Gorin high-pressure homogenizer (manufactured by Gorin), and the volume average particle diameter is 180 nm. A release agent particle dispersion 1 (solid content concentration: 20% by mass) obtained by dispersing release agent particles was prepared.

(Preparation of release agent particle dispersion 2)
Paraffin wax FT105 (manufactured by Nippon Seiwa Co., Ltd., melting temperature = 105 ° C.): 500 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 25 parts Ion-exchanged water: 1700 parts

  The above components were heated to 110 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then dispersed with a Menton Gorin high-pressure homogenizer (manufactured by Gorin), and the volume average particle size is 200 nm. Release agent particle dispersion 2 (solid content concentration: 20% by mass) prepared by dispersing release agent particles was prepared.

(Preparation of release agent particle dispersion 3)
Paraffin wax FT100 (manufactured by Nippon Seiwa Co., Ltd., melting temperature = 98 ° C.): 500 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 25 parts Ion-exchanged water: 1700 parts

  The above components were heated to 110 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then dispersed with a Menton Gorin high-pressure homogenizer (manufactured by Gorin), and the volume average particle size is 200 nm. A release agent particle dispersion 3 (solid content concentration: 20% by mass) obtained by dispersing release agent particles was prepared.

(Preparation of release agent particle dispersion 4)
Paraffin wax FNP0090 (manufactured by Nippon Seiwa Co., Ltd., melting temperature = 91 ° C.): 500 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 25 parts Ion-exchanged water: 1700 parts

  The above components were heated to 110 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then dispersed with a Menton Gorin high-pressure homogenizer (manufactured by Gorin), and the volume average particle size is 200 nm. A release agent particle dispersion 4 (solid content concentration: 20% by mass) obtained by dispersing release agent particles was prepared.

(Preparation of release agent particle dispersion 5)
・ Polywax 725 (Baker Petrolite Co., Ltd., melting temperature = 104 ° C.): 500 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 25 parts ・ Ion-exchanged water: 1700 parts

  The above components were heated to 110 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then dispersed with a Menton Gorin high-pressure homogenizer (manufactured by Gorin), and the volume average particle size is 200 nm. A release agent particle dispersion 5 (solid content concentration: 20% by mass) obtained by dispersing release agent particles was prepared.

(Preparation of release agent particle dispersion 6)
Paraffin wax HNP11 (manufactured by Nippon Seiwa Co., Ltd., melting temperature = 68 ° C.): 500 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 25 parts Ion-exchanged water: 1700 parts

  The above components were heated to 110 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then dispersed with a Menton Gorin high-pressure homogenizer (manufactured by Gorin), and the volume average particle size is 200 nm. A release agent particle dispersion 6 (solid content concentration: 20% by mass) obtained by dispersing release agent particles was prepared.

<Example 1>
(Preparation of toner particles 1)
Resin particle dispersion: 160 parts Colorant particle dispersion: 45 parts Release agent particle dispersion 1 (first release agent particles): 20 parts Ion exchange water: 300 parts

  The above components were sufficiently mixed and dispersed in a round stainless steel flask with Ultra Turrax T50 to obtain a solution. Next, 50 parts by mass of a 1% aluminum sulfate aqueous solution was added to this solution to produce core aggregated particles, which were dispersed using an ultra turrax at 7000 rpm for 5 minutes. Further, the solution in the flask was heated to 52 ° C. with stirring in an oil bath for heating and held at 52 ° C. for 60 minutes, and then 69 parts of resin particle dispersion liquid and release agent dispersion liquid 2 (second release agent) ) 5 parts and 30 parts of ion-exchanged water were added over 60 minutes to prepare core / shell aggregated particles.

  Thereafter, 0.5 mol / L sodium hydroxide aqueous solution was added to adjust the pH of the solution to 5.6, and then the stainless steel flask was sealed and heated to 96 ° C. while continuing stirring using a magnetic seal. After maintaining the time, it was cooled to 91 ° C. over 15 minutes, and then cooled to 30 ° C. with cold water at a rate of 8 ° C./min to obtain black toner particles.

Next, the black toner particles dispersed in the solution were filtered, thoroughly washed with ion exchange water, and then subjected to solid-liquid separation using No5A filter paper by Nutsche suction filtration. This was further redispersed in 3 L of ion exchanged water at 40 ° C., stirred and washed at 300 rpm for 15 minutes, and solid-liquid separated again.
This was further repeated 5 times, and when the electric conductivity of the filtrate reached 9.8 μS / cm, solid-liquid separation was performed using No5A filter paper by Nutsche suction filtration. The toner particles 1 were obtained by freeze-drying over time.

(Preparation of Toner 1)
Toner particles (1:50 parts) were added 3.5 mass of hydrophobic silica (TS720, manufactured by Cabot) as an external additive, and blended in a sample mill to obtain toner 1.

(Preparation of developer 1)
11 parts of toluene, 2 parts of diethylaminoethyl methacrylate-styrene-methyl methacrylate copolymer (copolymerization ratio: 2/20/78, weight average molecular weight 50,000), carbon black (manufactured by Cabot Corporation, R330R) 0.2 part and Glass beads (particle size 1 mm, the same amount as toluene) were put into a sand mill manufactured by Kansai Paint Co., Ltd., and stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming solution.

  Next, 100 parts of this coating resin layer forming solution and Mn—Mg ferrite particles (true specific gravity: 4.6 g / cm 3, volume average particle size: 35 μm, saturation magnetization: 65 emu / g) are placed in a vacuum deaeration type kneader. The mixture was stirred for 10 minutes while maintaining the temperature at 60 ° C., and then the pressure was reduced to distill off the toluene, thereby obtaining a ferrite carrier having a coating resin layer formed thereon.

To this ferrite carrier, toner 1 was mixed so that the toner concentration was 8% by mass , and stirred and mixed for 5 minutes by a ball mill to obtain developer 1 containing toner 1.

<Examples 2-8, Comparative Examples 1-6>
Developers 2 to 8 and Comparative developer 1 were the same as in Example 1 except that the type and amount of the release agent particle dispersion were changed as shown in Table 1, and the resin amount was changed by the ratio. ~ 6 was obtained.

<Example 9>
(Preparation of toner particles 9)
Resin particle dispersion: 160 parts Colorant particle dispersion: 45 parts Release agent particle dispersion 1 (first release agent particles): 20 parts Ion exchange water: 300 parts

  The above components were sufficiently mixed and dispersed in a round stainless steel flask with Ultra Turrax T50 to obtain a solution. Next, 50 parts of a 1% by weight aluminum sulfate aqueous solution was added to this solution to produce core aggregated particles, which were dispersed using an ultra turrax at 7000 rpm for 5 minutes. Further, the solution in the flask was heated to 52 ° C. with stirring in an oil bath for heating and held at 52 ° C. for 60 minutes, and then 69 parts of resin particle dispersion liquid and release agent dispersion liquid 2 (second release agent) ) 5 parts and 30 parts of ion-exchanged water were added over 60 minutes to prepare core / shell aggregated particles.

Thereafter, 0.5 mol / L sodium hydroxide aqueous solution was added to adjust the pH of the solution to 5.6, and then the stainless steel flask was sealed and heated to 90 ° C. while continuing stirring using a magnetic seal. After being held for a period of time, it was cooled to 85 ° C. over 15 minutes, and then cooled to 30 ° C. with cold water at a rate of 8 ° C./min to obtain black toner particles.
Thereafter, a developer 9 was obtained in the same manner as in Example 1.

<Examples 10 to 11 and Comparative Examples 7 to 8>
Developers 10 to 11 and Comparative developers 7 to 8 were obtained in the same manner as in Example 8, except that the conditions in the toner particle coalescence and coalescence process were changed as shown in Table 2.

<Various measurements>
For the developer toner obtained in each example, the content of the release agent in the surface layer side area (area%) in the cross-sectional observation of the toner before fixing, the peak P _a ¹ peak in the temperature rise spectrum of differential scanning calorimetry Top temperature T _a ¹ (° C.), endothermic amount of peak P _a ¹ (J / g), peak top temperature T _b ^{1 of} each of peaks P _b ¹ , P _b ² and P _b ³ in a temperature drop spectrum from 150 ° C. , T _b ² , and T _b ³ , and peak heights H ¹ , H ^2, and H ³ were measured according to the method described above. The results are shown in Table 3. The peak height is displayed in relative value with respect to H ^2.
FIG. 5 shows a temperature drop spectrum from 150 ° C. in the differential scanning calorimetry of the toner obtained in Example 1.

<Evaluation>
The following evaluation was performed about the developer obtained in each example.

(Image formation)
First, using a black and white multifunction device DocuCentre-IV 7080 manufactured by Fuji Xerox Co., Ltd., the developer, the toner cartridge, and the periphery of the toner supply mechanism in the main body are cleaned in an environment room at a temperature of 35 ° C. and a humidity of 50%. The developer was put into the machine, and the toner was put into the toner cartridge, which was then set in the multifunction machine main body. Subsequently, in order to charge the developer, 20 sheets of A3 paper were passed without being developed. Thereafter, plain paper (Fuji Xerox Co., Ltd .: P paper) was used, and the development amount of black toner on the paper was adjusted to 5.5 g / m ² . Then, as a toner image, a black solid image having an image density of 50 mm × 50 mm and a 100% image density is continuously output every 500. For the first, 300th, and 500th images, image adhesion and image gloss are obtained. Each degree was evaluated. The paper used was Fuji Xerox Co., Ltd .: P paper and Business 4200 Paper (XEROX).

(Evaluation of paper adhesion)
The adhesion between sheets after fixing was evaluated visually according to the following criteria. The results are shown in Table 4.
G1: Not attached.
G2: Adhering, but naturally peels off due to the weight of the paper, and there is no image defect G3: Adhering, peeling sound is generated when peeling, but there is no image defect and there is no practical problem.
G4: Adhering, after peeling, there is an image defect and there is a problem.

(Glossiness evaluation)
About the image part of the solid image, the glossiness was measured using a 75-degree specular gloss meter GM-26D (Murakami Color Research Laboratory Co., Ltd. product). The difference in image glossiness between the 300th sheet and the 500th sheet with respect to the first image glossiness was evaluated according to the following criteria. The results are shown in Table 5.
G1: Glossiness difference is less than 5 G2: Glossiness difference is 5 or more and less than 15 G3: Glossiness difference is 15 or more and less than 25 G4: Glossiness difference is 25 or more

  From the above results, in this embodiment, compared to the comparative example, good results were obtained for both the evaluation of adhesion between the recording media after fixing the toner image and the evaluation of the suppression of the change in the glossiness at the continuous output. I understand that.

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

Claims (6)

Including a binder resin and a release agent,
The binder resin includes a styrene- (meth) acrylic copolymer resin,
The mold release agent includes two or more paraffinic waxes having different melting temperatures,
The total content of the release agent is 3.0% by mass or more and 5.0% by mass or less,
When a cross-sectional image analysis is performed using a scanning transmission electron microscope, 50% by area or more of the release agent displayed in the image has a depth from the outer peripheral portion to a radius of / 2. Exists in the area,
An electrostatic image developing toner satisfying the following (1) , (2) and (3) by differential scanning calorimetry.
(1) In the first temperature rise spectrum,
There is a peak P _a ¹ whose endotherm is greater than 2 J / g in absolute value,
Temperature _T ^{a 1} peak top of the peak _P ^{a 1} is at 70 ° C. or higher 100 ° C. or less.
(2) In the temperature drop spectrum from 150 ° C.
A peak P _b ¹ having a peak top in a temperature range of 70 ° C. or more and 92 ° C. or less;
Peak _P ^{b 2} having a peak top at the peak _P ^{when b 1} of the temperature of the peak top was ^{_{T b 1 (T b 1 -20}} ) ℃ or higher ^_(T b 1 -3) ° C. temperature range below,
There is a peak P _b ³ having a peak top in a temperature range of 53 ° C. or more and less than 67 ° C.
(3) the peak _P ^{b 2} of the peak height ^{H 2} is higher than the peak height ^{H 3} of the peak _P peak of ^{b 1} height ^{H 1} and the peak _P ^{b 3.} An electrostatic image developer comprising the electrostatic image developing toner according to claim 1 . Containing the toner for developing an electrostatic image according to claim 1 ;
A toner cartridge to be attached to and detached from the image forming apparatus. A developing means for accommodating the electrostatic charge image developer according to claim 2 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer,
A process cartridge attached to and detached from the image forming apparatus. An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Development means for containing the electrostatic charge image developer according to claim 2 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer,
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising: A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer according to claim 2 ;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
An image forming method comprising: