Toner for developing electrostatic images, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

Abstract

To provide an electrostatic charge image development toner which produces secondary color images with a wide color gamut.SOLUTION: An electrostatic charge image development toner provided herein comprises toner particles containing a binder resin and a colorant, where a Net strength NS of sulfur and a total Net strength NA of an alkali metal and an alkali earth metal as measured by fluorescent X-ray analysis satisfy a relationship expressed as 1.0<NS / NA<22.0.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a toner for developing an electrostatic image, an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method. [Background technology]

[0002] Methods for visualizing image information, such as electrophotography, are currently used in various fields. In electrophotography, an electrostatic image is formed as image information on the surface of an image carrier by charging and forming an electrostatic image. Then, a toner image is formed on the surface of the image carrier by a developer containing a toner, and the toner image is transferred to a recording medium, and then fixed to the recording medium. Through these steps, the image information is visualized as an image.

[0003] For example, Patent Document 1 discloses a toner having "toner particles containing at least a binder resin, a colorant, a release agent, and a resin having sulfur atoms, and an inorganic fine powder mixed with the toner particles, characterized in that i) the toner particles contain at least one element selected from the group consisting of magnesium, calcium, barium, zinc, aluminum, and phosphorus, and satisfy the following formula, 4≦(total content of the above elements (T): ppm) / (content of sulfur element (S): ppm)≦30, ii) the weight average particle diameter (D4) of the toner is 3 μm to 10 μm, and iii) the average circularity of the toner is 0.950 to 0.995."

[0004] Also, Patent Document 2 discloses "a toner having core particles containing at least a binder resin, a colorant, and a release agent, and a coating layer covering the core particles, wherein the coating layer is formed by fixing resin fine particles on the surface of the core particles after forming the core particles, and the difference (Tg2 - Tg1) (°C) between the glass transition temperature Tg1 (°C) of the core particles and the glass transition temperature Tg2 (°C) of the resin fine particles is 5 to 40 °C, the resin fine particles are composed of a resin containing at least a carboxyl group and a sulfonic acid group, and the sulfur element contained in the coating layer is 0.005 to 0.050% by mass based on the toner particles."

[0005] Also, Patent Document 3 discloses "toner particles containing a binder resin, a sulfur element, and one element selected from Al and Mg, and when the Net intensity by fluorescent X-ray (XRF) analysis of the sulfur element contained in the toner particles is Cs (kcps), and the Net intensity by fluorescent X-ray (XRF) analysis of one element selected from Al and Mg contained in the toner particles is Cm (kcps), an electrostatic latent image developing toner satisfying the following relational expressions (1): 0.2 < Cm < 0.4 and (2): 4.5 < Cs / Cm < 5.5."

[0006] Also, Patent Document 4 discloses "a transparent toner characterized in that the volume average primary particle size is 18 μm or more and 28 μm or less, and the content (composition ratio) of the sulfur element measured by fluorescent X-ray is 0.01% or more and 0.1% or less."

[0007] Also, Patent Document 5 discloses "toner particles containing a binder resin and a release agent, and when the amount of sulfur element in the domain portion of the release agent analyzed by an energy dispersive X-ray analyzer (EDX) of the cross section of the toner particles is B, an electrostatic charge image developing toner in which the value of B is 0.2 atomic% or more and 1.5 atomic% or less."

[0008] Furthermore, Patent Document 6 discloses "a toner for developing electrostatic images, which contains toner base particles having an external additive on the surface thereof, the toner for developing electrostatic images being characterized in that the external additive contains at least silica particles, and the silica particles contain elemental sulfur." [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2005-62807 A [Patent Document 2] JP 2010-181802 A [Patent Document 3] JP 2011-209313 A [Patent Document 4] JP 2013-130794 A [Patent Document 5] JP 2018-25723 A [Patent Document 6] JP 2018-180279 A Summary of the Invention [Problem to be solved by the invention]

[0010] The object of the present invention is to provide a composite material containing a binder resin and a colorant, and having a net sulfur intensity N S and the net strength N of the alkali metals and alkaline earth metals A And, 15 ≧ N S / N A The object of the present invention is to provide a toner for developing electrostatic images which can form secondary color images having a wider color gamut than a toner having toner particles which satisfy the above relationship. [Means for solving the problem]

[0011] Means for solving the above problems include the following aspects.

[0012] <1> The net sulfur intensity N, measured by X-ray fluorescence analysis, includes the binder resin and colorant. S and the net strength N of the alkali metals and alkaline earth metals A But, 1.0 <N S / N A A toner for developing electrostatic images, the toner particles of which satisfy the relationship: <2> Net strength of sulfur N S and the net strength N of the total of the alkali metals and alkaline earth metals A But, 1.0 <N S / N A <18.0 Meet Relationships <1> 2. The toner for developing electrostatic images according to claim 1 . <3> Net strength of sulfur N S is between 3.0kcps and 6.0kcps <1> or <2> 2. The toner for developing electrostatic images according to claim 1 . <4> Net strength of sulfur N S is between 3.5kcps and 5.5kcps <3> 2. The toner for developing electrostatic images according to claim 1 . <5> The net strength N of the sum of the alkali metals and alkaline earth metals A is between 0.2kcps and 4.2kcps <1> ~ <4> 2. The toner for developing an electrostatic image according to claim 1 . <6> The net strength N of the sum of the alkali metals and alkaline earth metals A is between 2.0kcps and 4.0kcps <5> 2. The toner for developing electrostatic images according to claim 1 . <7> In the toner particles, the net intensity N of chlorine measured by fluorescent X-ray analysis Cl is 0.10 kcps or more and 1.30 kcps or less, and the net strength N S and the net strength of chlorine N Cl And 3 <N S / N Cl Meet <40 Relationships <1> ~ <6> 2. The toner for developing an electrostatic image according to claim 1 . <8> The alkali metal and alkaline earth metal include at least one selected from the group consisting of Na, Mg, and Ca. <1> ~ <7> 2. The toner for developing an electrostatic image according to claim 1 . <9> In the toner particles, the net intensity N S and the net strength of Mg, N M But, 15.0 <N S / N M <22.0 fulfillment relationship <1> ~ <8> 2. The toner for developing electrostatic images according to claim 1 . <10> The toner particles contain an amorphous polyester resin and a crystalline polyester resin as the binder resin. <1> ~ <9> 2. The toner for developing an electrostatic image according to claim 1 . <11> The crystalline polyester resin is a polymer of an α,ω-linear aliphatic dicarboxylic acid and an α,ω-linear aliphatic diol. <10> 2. The toner for developing electrostatic images according to claim 1 . <12> The polymer of an α,ω-linear aliphatic dicarboxylic acid and an α,ω-linear aliphatic diol is a polymer of 1,10-decanedicarboxylic acid and 1,6-hexanediol. <11> 2. The toner for developing electrostatic images according to claim 1 . <13> The toner particles contain a release agent. <1> ~ <12> 2. The toner for developing an electrostatic image according to claim 1 . <14> The release agent is an ester wax. <13> 2. The toner for developing electrostatic images according to claim 1 . <15> When a cross section of the toner particle is observed, the area ratio of the colorant dispersion region in the cross section of the toner particle is 60% or more and 95% or less. <1> ~ <14> 2. The toner for developing an electrostatic image according to claim 1 . <16> The net sulfur intensity N, measured by X-ray fluorescence analysis, includes the binder resin and colorant. S and the net strength N of the alkali metals and alkaline earth metals A The difference is 0.8 <N S -N A A toner for developing electrostatic images, the toner particles of which satisfy the relationship of <5.0. <17> <1> ~ <16> 2. An electrostatic image developer comprising the toner for developing electrostatic images according to claim 1. <18> <1> ~ <16> The toner for developing an electrostatic image according to any one of claims 1 to 4 is contained in the container. A toner cartridge that is detachably attached to an image forming apparatus. <19> <17> and a developing unit which develops an electrostatic image formed on a surface of an image carrier into a toner image by using the electrostatic image developer, A process cartridge that is detachably attached to an image forming apparatus. <20> An image carrier; a charging means for charging the surface of the image carrier; an electrostatic image forming means for forming an electrostatic image on the charged surface of the image carrier; <17> a developing means for developing the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer; a transfer means for transferring the toner image formed on the surface of the image carrier to a surface of a recording medium; a fixing means for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising: <21> a charging step of charging a surface of an image carrier; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier; <17> a developing step of developing the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer according to claim 1; a transfer step of transferring the toner image formed on the surface of the image carrier onto a surface of a recording medium; a fixing step of fixing the toner image transferred onto the surface of the recording medium; The image forming method according to claim 1, Effect of the Invention

[0013] <1> According to the present invention, a binder resin and a colorant are contained, and the net intensity N of sulfur measured by fluorescent X-ray analysis is S and the net strength N of the alkali metals and alkaline earth metals A And, 1.0 ≧ N S / N AThe present invention provides a toner for developing electrostatic images which forms a secondary color image having a wider color gamut than a toner having toner particles which satisfy the above relationship. <2> According to the present invention, the net strength N S and the net strength N of the alkali metals and alkaline earth metals A And, 1.0 ≧ N S / N A As a result, there is provided a toner for developing electrostatic images which forms a secondary color image having a wider color gamut than when the above relationship is satisfied. <3> According to the present invention, the net strength N S In comparison with a toner having a toner viscosity of less than 3.0 kcps, a toner for developing electrostatic images is provided which forms secondary color images having a wider color gamut. <4> According to the present invention, the net strength N S This provides a toner for developing electrostatic images that forms secondary color images having a wider color gamut than when the toner has a toner density of less than 3.5 kcps. <5> According to the invention, the net strength N of the total of alkali metals and alkaline earth metals A However, in comparison with the case where the toner density is less than 0.2 kcps, a toner for developing electrostatic images is provided which forms secondary color images having a wider color gamut. <6> According to the invention, the net strength N of the total of alkali metals and alkaline earth metals A However, in comparison with a case where the toner viscosity is less than 2.0 kcps, a toner for developing electrostatic images is provided which forms secondary color images having a wider color gamut. <7> According to the invention, the net strength of chlorine N Cl is less than 0.10 kcps, or the net strength of sulfur N S and the net strength of chlorine N Cl and 3 ≧ N S / N Cl As a result, there is provided a toner for developing electrostatic images which forms a secondary color image having a wider color gamut than when the above relationship is satisfied. <8> According to the present invention, there is provided a toner for developing electrostatic images that forms secondary color images with a wider color gamut than when the alkali metal and alkaline earth metal contain only elements other than Na, Mg, and Ca. <9> According to the present invention, the net strength N Sand the net strength of Mg, N M And, 15.0 ≧ N S / N M As a result, there is provided a toner for developing electrostatic images which forms a secondary color image having a wider color gamut than when the above relationship is satisfied. <10> According to the present invention, a binder resin and a colorant are contained, and the net intensity N of sulfur measured by fluorescent X-ray analysis is S and the net strength N of the alkali metals and alkaline earth metals A And, 1.0 ≧ N S / N A In comparison with a toner having toner particles satisfying the above relationship, there is provided a toner for developing electrostatic images which forms a secondary color image having a wide color gamut even when the toner particles contain a crystalline polyester resin as a binder resin. <11> or <12> According to the present invention, there is provided a toner for developing electrostatic images that forms secondary color images having a wider color gamut than when the crystalline polyester resin is a resin other than a polymer of an α,ω-linear aliphatic dicarboxylic acid and an α,ω-linear aliphatic diol. <13> According to the present invention, a binder resin and a colorant are contained, and the net intensity N of sulfur measured by fluorescent X-ray analysis is S and the net strength N of the alkali metals and alkaline earth metals A And, 1.0 ≧ N S / N A Thus, there is provided a toner for developing electrostatic images which can form secondary color images having a wider color gamut than a toner having toner particles which satisfy the relationship above, even when the toner particles contain a release agent. <14> According to the present invention, there is provided a toner for developing electrostatic images that can form secondary color images having a wider color gamut than when the release agent is carbamate wax. <15> According to the present invention, a binder resin and a colorant are contained, and the net intensity N of sulfur measured by fluorescent X-ray analysis is S and the net strength N of the alkali metals and alkaline earth metals A And, 1.0 ≧ N S / N AThe present invention provides a toner for developing electrostatic images that forms a secondary color image having a wide color gamut even when the area ratio of the colorant-dispersed region in the cross section of the toner particle is 60% or more and 95% or less, compared to a toner for developing electrostatic images having toner particles that satisfy the above relationship. <16> According to the present invention, a binder resin and a colorant are contained, and the net intensity N of sulfur measured by fluorescent X-ray analysis is S and the net strength N of the alkali metals and alkaline earth metals A The difference between these is 0.8 or more. S -N A The present invention provides a toner for developing electrostatic images that forms a secondary color image having a wider color gamut than a toner for developing electrostatic images having toner particles that satisfy the above relationship.

[0014] <17> , <18> , <19> , <20> or <21> According to the present invention, a binder resin and a colorant are contained, and the net intensity N of sulfur measured by fluorescent X-ray analysis is S and the net strength N of the alkali metals and alkaline earth metals A And, 1.0 ≧ N S / N A The present invention provides an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, or an image forming method that can form a secondary color image having a wider color gamut than when a toner for developing an electrostatic image having toner particles that satisfy the above relationship is used. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram illustrating an example of a process cartridge that is detachably mounted to the image forming apparatus according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described as an example. These descriptions and examples are for illustrating the present invention, but are not intended to limit the present invention.

[0017] In this specification, a numerical range indicated using "~" indicates a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in this specification, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in another stepwise manner. In addition, in the numerical ranges described in this disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.

[0018] In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes, so long as the intended purpose of the process is achieved.

[0019] When an embodiment is described with reference to the drawings in this specification, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the size of the members in each drawing is conceptual, and the relative relationship between the sizes of the members is not limited to this.

[0020] In the present specification, each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition in the present disclosure, if multiple substances corresponding to each component are present in the composition, the total amount of the multiple substances present in the composition is meant unless otherwise specified.

[0021] In the present specification, the particles corresponding to each component may include multiple types. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

[0022] In this specification, "toner for developing electrostatic images" is also referred to simply as "toner", and "electrostatic image developer" is also referred to simply as "developer".

[0023] As used herein, "alkali metal" refers to Li, Na, K, Rb, Cs, and Fr. Additionally, the term "alkaline earth metal" refers to Be, Mg, Ca, Sr, Ba, and Ra.

[0024] <Toner for developing electrostatic images> -First embodiment- The toner according to the first embodiment contains a binder resin and a colorant, and has a sulfur net intensity N S and the net strength N of the alkali metals and alkaline earth metals A But, 1.0 <N S / N A The toner particles satisfy the relationship:

[0025] Here, if the dispersibility of the colorant in the toner particles is low, the color gamut of the obtained secondary color image will be narrow. In particular, in the case of low pressure fixing (for example, fixing by a fixing device using an electromagnetic induction heating method), the toner particles are difficult to melt sufficiently, so the color gamut of the secondary color image is likely to be narrow.

[0026] In contrast, the toner according to the first embodiment can form a secondary color image with a wide color gamut due to the above-mentioned configuration. The reason for this is presumed to be as follows.

[0027] The alkali metals and alkaline earth metals contained in the toner particles have the effect of aggregating the colorant, but the aggregating force is weak and suppresses local aggregation of the colorant. The sulfur contained in the toner particles has the effect of preventing the primary particles of the colorant from agglomerating and allowing the colorant to exist stably in the toner particles. By making sulfur exist in the toner particles in a large amount relative to the alkali metals and alkaline earth metals having such an action (i.e., the net strength N S and the net strength N of the alkali metals and alkaline earth metals A But, 1.0 <N S / N A<22.0), the dispersibility of the colorant in the toner particles is improved. This is thought to be because a balance is achieved by including more sulfur, which has a relatively large ionic radius and a weak ability to stabilize particles, in contrast to alkali metals and alkaline earth metals, which have a relatively small ionic radius and a strong coagulating effect. By improving the dispersibility of the colorant in the toner particles, the dispersibility of the colorant in the fixed image is also improved, and the color gamut of the secondary color image is expanded.

[0028] From the above, it is presumed that the toner according to the first embodiment can form a secondary color image with a wide color gamut.

[0029] -Second embodiment- The toner according to the second embodiment contains a binder resin and a colorant, and has a sulfur net intensity N S and the net strength N of the alkali metals and alkaline earth metals A The difference is 0.8 <N S -N A The toner particles have a relationship of 0.5 to 5.0.

[0030] The toner according to the second embodiment can also form a secondary color image with a wide color gamut by the above-mentioned configuration. The reason is that, like the first embodiment, a large amount of sulfur is present in the toner particles relative to the alkali metal and alkaline earth metal (that is, the net strength N S and the net strength N of the alkali metals and alkaline earth metals A The difference is 0.8 <N S -N A <5.0), the dispersibility of the colorant in the toner particles is improved.

[0031] Hereinafter, a toner corresponding to both the toner according to the first and second embodiments (hereinafter also referred to as "toner according to the present embodiment") will be described in detail. However, an example of the toner of the present invention may be a toner corresponding to either the toner according to the first or second embodiment.

[0032] The toner according to the exemplary embodiment includes toner particles, and may include an external additive that is added to the toner particles.

[0033] [Toner particles] (Net intensity of each element in toner particles measured by X-ray fluorescence analysis) Net intensity of sulfur in toner particles N S and the net strength N of the alkali metals and alkaline earth metals A What is 1.0? <N S / N A <22.0 relationship. N S / N A By making N exceed 1.0, the color gamut of the secondary color image is improved. S / N A By making the value less than 22.0, the decrease in transfer efficiency is suppressed. From the viewpoint of improving the color gamut of secondary color images, the net intensity of sulfur N S and the net strength N of the alkali metals and alkaline earth metals A What is 1.0? <N S / N A It is preferable that the relationship satisfies <20.0, and 1.0 <N S / N A It is more preferable that the relationship be <18.0. In addition, N S / N A From the viewpoint of improving the color gamut of the secondary color image, it may be 10.0 or more, or 15.0 or more.

[0034] Net sulfur intensity N in toner particles measured by X-ray fluorescence analysis S and the net strength N of the alkali metals and alkaline earth metals A The difference is 0.8 <N S -N A Meet <5.0 relationship. N S -N A By increasing the resolution to more than 0.8 kcps, the color gamut of the secondary color image is improved. S -N ABy setting the transfer rate to less than 5.0 kcps, the decrease in transfer efficiency is suppressed. From the viewpoint of improving the color gamut of secondary color images, the net intensity of sulfur N S and the net strength N of the alkali metals and alkaline earth metals A The difference is 0.9 <N S -N A It is preferable that the relationship satisfies <4.8, and 1.0 <N S -N A It is more preferable to satisfy a relationship of <4.5. In addition, N S -N A From the viewpoint of improving the color gamut of the secondary color image, it may be 2.0 or more, or 3.0 or more.

[0035] Net intensity of sulfur in toner particles N S is preferably from 2.5 kcps to 6.5 kcps, more preferably from 3.0 kcps to 6.0 kcps, and even more preferably from 3.5 kcps to 5.5 kcps. Net strength of sulfur N S When the amount of the colorant contained in the ink is within the above range, the dispersibility of the colorant is improved, and the color gamut of the secondary color image is improved.

[0036] In the toner particles, the net intensity N of the total of alkali metals and alkaline earth metals A is preferably 0.2 kcps or more and 4.2 kcps or less, more preferably 1.0 kcps or more and 4.1 kcps or less, and even more preferably 2.0 kcps or more and 4.0 kcps or less. Sulfur Net Strength N S When the amount of the colorant contained in the toner is within the above range, local aggregation of the colorant is suppressed, and the color gamut of the secondary color image is improved.

[0037] In the toner particles, the net strength of chlorine N Cl is preferably 0.05 kcps or more and 1.35 kcps or less, more preferably 0.10 kcps or more and 1.30 kcps or less, and even more preferably 0.08 kcps or more and 1.25 kcps or less. Chlorine Net Strength N ClWhen the amount of sulfur is within the above range, the dispersibility of sulfur in the toner particles is improved, and as a result, the dispersibility of the colorant by sulfur is also improved, and the color gamut of the secondary color image is improved.

[0038] Net intensity of sulfur in toner particles N S and the net strength of chlorine N Cl And, 2.5 <N S / N Cl <50, and 3 <N S / N Cl <40 is more preferable, and 4 <N S / N Cl It is even more preferable that the relationship <35 is satisfied. Sulfur Net Strength N S and the net strength of chlorine N Cl When the ratio is within the above range, the dispersibility of sulfur in the toner particles is improved, which in turn improves the dispersibility of the colorant by sulfur, thereby improving the color gamut of the secondary color image.

[0039] Here, from the viewpoint of improving the color gamut of the secondary color image, the alkali metal and alkaline earth metal preferably include at least one selected from the group consisting of Na, Mg, and Ca, and more preferably include Mg. And, in particular, the net strength of sulfur N S and the net strength of Mg, N M What is 14.0 <N S / N M It is preferable that the relationship satisfies <25.0, and 15.0 <N S / N M <22.0 is more preferable, and 17.0 <N S / N M It is more preferable that the relationship be <20.0.

[0040] An example of the supply source of each element that makes the net intensity of each element in the toner particles fall within the above range is as follows.

[0041] Examples of the sulfur source include additives containing sulfur (surfactants, flocculants, chain transfer agents, initiators, etc.). Specifically, examples of the sulfur source include metal sulfates, metal sulfonates, and metal sulfides. Examples of metal sulfates include alkali metal sulfates (lithium sulfate, sodium sulfate, potassium sulfate, rubidium sulfate, cesium sulfate, francium sulfate, etc.), alkaline earth metal sulfates (beryllium sulfate, magnesium sulfate, calcium sulfate, strontium sulfate, barium sulfate, radium sulfate, etc.), aluminum sulfate, and polyiron (II) sulfate. Examples of the metal sulfonate include metal alkylbenzenesulfonates (such as sodium dodecylbenzenesulfonate and calcium dodecylbenzenesulfonate). The sulfides include calcium polysulfide and the like. Sources of sulfur also include alkanediols, such as dodecanethiol.

[0042] The source of the alkali metal includes additives containing an alkali metal (surfactants, flocculants, etc.) Specifically, examples of additives containing an alkali metal include alkali metal salts. Examples of the alkali metal salt include lithium salts such as lithium chloride, lithium sulfate, and lithium nitrate; sodium salts such as sodium chloride, sodium sulfate, and sodium nitrate; potassium salts such as potassium chloride, potassium sulfate, and potassium nitrate; rubidium salts such as rubidium chloride, rubidium sulfate, and rubidium nitrate; cesium salts such as cesium chloride, cesium sulfate, and cesium nitrate; and francium salts such as francium chloride, francium sulfate, and francium nitrate. Examples of the alkali metal salts include alkali metal sulfonates (eg, sodium alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate).

[0043] The alkaline earth element supply source includes additives (surfactants, flocculants, etc.) containing alkaline earth elements. Specifically, the additives containing alkaline earth metals include, for example, alkaline earth metal salts. Examples of alkaline earth metal salts include beryllium salts such as beryllium chloride, beryllium sulfate, and beryllium nitrate; magnesium salts such as magnesium chloride, magnesium sulfate, and magnesium nitrate; calcium salts such as calcium chloride, calcium sulfate, and calcium nitrate; strontium salts such as strontium chloride, strontium sulfate, and strontium nitrate; barium salts such as barium chloride, barium sulfate, and barium nitrate; and radium salts such as radium chloride, radium sulfate, and radium nitrate. Examples of the alkali metal salt include alkaline earth metal sulfonates (eg, calcium alkylbenzenesulfonates such as calcium dodecylbenzenesulfonate) and metal sulfides (eg, calcium polysulfide).

[0044] The chlorine supply source may be an additive containing chlorine (such as a flocculant). Specifically, the additive containing chlorine may be, for example, a chloride. The chloride may be, for example, ammonium chloride, aluminum chloride, polyaluminum chloride, iron (II) chloride, zinc chloride, alkali metal chloride (lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, francium chloride, etc.), alkaline earth metal chloride (beryllium chloride, magnesium chloride, strontium chloride, barium chloride, radium chloride, etc.), etc.

[0045] The range of net intensity of each element is adjusted by adjusting the amount of the supply source of each element added.

[0046] The method for measuring the net strength of each element is as follows. Approximately 200 mg of toner particles (if an external additive is added to the toner particles, the toner particles to which the external additive has been added) are compressed with a compression molding machine under a load of 10 t for 60 seconds to produce a disk with a diameter of 10 mm and a thickness of 2 mm. This disk is used as a sample and a total element analysis is performed under the following measurement conditions using a scanning X-ray fluorescence analyzer (Rigaku ZSX Primus II), and the net intensity (unit: kilo counts per second, kcps) of each element to be measured is determined. Tube voltage: 40kV ·Tube current: 70mA ·Anti-cathode: Rhodium Measurement time: 15 minutes ·Analysis diameter: 10mm in diameter

[0047] (Composition of toner particles) The toner particles are configured to contain, for example, a binder resin, and, if necessary, a colorant, a release agent, and other additives.

[0048] -Binding resin- Examples of the binder resin include vinyl resins made of homopolymers of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers of two or more of these monomers. Examples of the binder resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin, mixtures of these with the vinyl resins, and graft polymers obtained by polymerizing vinyl monomers in the coexistence of these. These binder resins may be used alone or in combination of two or more kinds.

[0049] In particular, it is preferable to use a combination of an amorphous resin and a crystalline resin as the binder resin, and it is more preferable to use a combination of an amorphous polyester resin and a crystalline polyester resin. When a crystalline resin (particularly a crystalline polyester resin) is used together with an amorphous resin (particularly an amorphous polyester resin) as a crystalline resin, the low-temperature fixing property of the toner is improved. On the other hand, the crystalline resin (particularly a crystalline polyester resin) exists in the form of a domain in the toner particles, and the domain region of the crystalline resin becomes a region in which the colorant is difficult to disperse, and the region in the toner particle in which the colorant is dispersed is limited. Therefore, when the toner particles contain a crystalline resin (particularly a crystalline polyester resin), the color gamut of the secondary color image is likely to decrease. However, the net strength of sulfur N S and the net strength N of the alkali metals and alkaline earth metals A By controlling the above, even if the area in the toner particles where the colorant is dispersed is limited, the dispersibility of the colorant is increased, and thus the decrease in the color gamut of the secondary color image caused by the inclusion of a crystalline resin (particularly a crystalline polyester resin) in the toner particles is suppressed.

[0050] Here, the term "amorphous resin" refers to a resin that, in a thermal analysis measurement using differential scanning calorimetry (DSC), has only a stepwise endothermic change rather than a clear endothermic peak, is a solid at room temperature, and is thermoplasticized at a temperature equal to or higher than the glass transition temperature. On the other hand, a crystalline resin refers to a resin that has a clear endothermic peak rather than a stepwise change in endothermic amount in differential scanning calorimetry (DSC). Specifically, for example, a crystalline resin means a resin whose half-width of an endothermic peak is within 10°C when measured at a heating rate of 10°C / min, and an amorphous resin means a resin whose half-width exceeds 10°C or a resin in which no clear endothermic peak is observed.

[0051] The amorphous resin will now be described. Examples of the amorphous resin include known amorphous resins such as amorphous polyester resin, amorphous vinyl resin (e.g., styrene-acrylic resin, etc.), epoxy resin, polycarbonate resin, polyurethane resin, etc. Among these, amorphous polyester resin and amorphous vinyl resin (particularly styrene-acrylic resin) are preferred, and amorphous polyester resin is more preferred. In addition, it is also a preferred embodiment to use an amorphous polyester resin and a styrene-acrylic resin in combination as the amorphous resin. It is also a preferred embodiment to use an amorphous resin having an amorphous polyester resin segment and a styrene-acrylic resin segment as the amorphous resin.

[0052] Amorphous polyester resin The amorphous polyester resin may be, for example, a condensation polymer of a polyvalent carboxylic acid and a polyhydric alcohol. As the amorphous polyester resin, a commercially available product or a synthesized product may be used.

[0053] Examples of polyvalent carboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as the polyvalent carboxylic acid. The polyvalent carboxylic acid may be a trivalent or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower (e.g., carbon number 1 to 5) alkyl esters thereof. The polyvalent carboxylic acids may be used alone or in combination of two or more kinds.

[0054] Examples of polyhydric alcohols include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, aromatic diols and alicyclic diols are preferred as polyhydric alcohols, and aromatic diols are more preferred. As the polyhydric alcohol, a polyhydric alcohol having a crosslinked or branched structure of three or more may be used in combination with the diol. Examples of the polyhydric alcohol having a trihydric or higher valence include glycerin, trimethylolpropane, and pentaerythritol. The polyhydric alcohols may be used alone or in combination of two or more kinds.

[0055] The amorphous polyester resin is obtained by a known manufacturing method. Specifically, for example, the polymerization temperature is set to 180°C or more and 230°C or less, the reaction system is depressurized as necessary, and the reaction is carried out while removing water and alcohol generated during condensation. If the raw material monomer is not dissolved or compatible at the reaction temperature, a high-boiling point solvent may be added as a dissolution aid to dissolve it. In this case, the polycondensation reaction is carried out while distilling off the dissolution aid. If a monomer with poor compatibility is present in the copolymerization reaction, it is recommended that the monomer with poor compatibility is condensed in advance with the acid or alcohol to be polycondensed with the monomer and then polycondensed with the main component.

[0056] The amorphous polyester resin may be a modified amorphous polyester resin in addition to an unmodified amorphous polyester resin. The modified amorphous polyester resin is an amorphous polyester resin having a bond group other than an ester bond, or an amorphous polyester resin having a resin component different from polyester bonded by a covalent bond or an ionic bond. The modified amorphous polyester resin may be, for example, a resin modified at the end by reacting an amorphous polyester resin having a functional group such as an isocyanate group introduced at the end with an active hydrogen compound.

[0057] The proportion of the amorphous polyester resin in the total binder resin is preferably 60% by mass or more and 98% by mass or less, more preferably 65% ​​by mass or more and 95% by mass or less, and even more preferably 70% by mass or more and 90% by mass or less.

[0058] Styrene acrylic resin The styrene-acrylic resin is a copolymer obtained by copolymerizing at least a styrene-based monomer (a monomer having a styrene skeleton) and a (meth)acrylic-based monomer (a monomer having a (meth)acrylic group, preferably a monomer having a (meth)acryloxy group). The styrene-acrylic resin includes, for example, a copolymer of a styrene monomer and a (meth)acrylic acid ester monomer. The acrylic resin portion of the styrene-acrylic resin is a partial structure formed by polymerizing either an acrylic monomer or a methacrylic monomer, or both. In addition, the term "(meth)acrylic" includes both "acrylic" and "methacrylic".

[0059] Examples of the styrene monomer include styrene, α-methylstyrene, metachlorostyrene, parachlorostyrene, parafluorostyrene, paramethoxystyrene, meta-tert-butoxystyrene, para-tert-butoxystyrene, paravinylbenzoic acid, paramethyl-α-methylstyrene, etc. The styrene monomer may be used alone or in combination of two or more kinds.

[0060] Examples of the (meth)acrylic monomer include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc. The (meth)acrylic monomer may be used alone or in combination of two or more.

[0061] The polymerization ratio of the styrene-based monomer to the (meth)acrylic monomer is preferably styrene-based monomer:(meth)acrylic monomer=70:30 to 95:5 on a mass basis.

[0062] The styrene-acrylic resin may have a crosslinked structure. The styrene-acrylic resin having a crosslinked structure can be produced, for example, by copolymerizing a styrene-based monomer, a (meth)acrylic monomer, and a crosslinkable monomer. The crosslinkable monomer is not particularly limited, but is preferably a bifunctional or higher (meth)acrylate compound.

[0063] The method for producing the styrene-acrylic resin is not particularly limited, and for example, solution polymerization, precipitation polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, etc. The polymerization reaction is carried out by a known operation (for example, a batch system, a semi-continuous system, a continuous system, etc.).

[0064] The proportion of the styrene-acrylic resin in the total binder resin is preferably from 0% to 20% by mass, more preferably from 1% to 15% by mass, and even more preferably from 2% to 10% by mass.

[0065] Amorphous resin having an amorphous polyester resin segment and a styrene-acrylic resin segment (hereinafter also referred to as "hybrid amorphous resin") The hybrid amorphous resin is an amorphous resin in which an amorphous polyester resin segment and a styrene-acrylic resin segment are chemically bonded to each other. Examples of the hybrid amorphous resin include a resin having a main chain made of a polyester resin and a side chain made of a styrene-acrylic resin chemically bonded to the main chain; a resin having a main chain made of a styrene-acrylic resin and a side chain made of a polyester resin chemically bonded to the main chain; a resin having a main chain formed by chemically bonding a polyester resin and a styrene-acrylic resin; a resin having a main chain formed by chemically bonding a polyester resin and a styrene-acrylic resin, and at least one of a side chain made of a polyester resin chemically bonded to the main chain and a side chain made of a styrene-acrylic resin chemically bonded to the main chain; and the like.

[0066] The amorphous polyester resin and the styrene-acrylic resin in each segment are as described above, and therefore the description thereof will be omitted.

[0067] The total amount of the polyester resin segment and the styrene-acrylic resin segment in the entire hybrid amorphous resin is preferably 80 mass% or more, more preferably 90 mass% or more, even more preferably 95 mass% or more, and even more preferably 100 mass%.

[0068] In the hybrid amorphous resin, the proportion of the styrene-acrylic resin segment in the total amount of the polyester resin segment and the styrene-acrylic resin segment is preferably 20% by mass or more and 60% by mass or less, more preferably 25% by mass or more and 55% by mass or less, and even more preferably 30% by mass or more and 50% by mass or less.

[0069] The hybrid amorphous resin is preferably produced by any one of the following methods (i) to (iii). (i) After preparing a polyester resin segment by condensation polymerization of a polyhydric alcohol and a polycarboxylic acid, a monomer constituting a styrene-acrylic resin segment is addition-polymerized. (ii) A styrene-acrylic resin segment is prepared by addition polymerization of an addition-polymerizable monomer, and then a polyhydric alcohol and a polycarboxylic acid are condensation-polymerized. (iii) Polycondensation of a polyhydric alcohol and a polycarboxylic acid and addition polymerization of an addition-polymerizable monomer are carried out in parallel.

[0070] The proportion of the hybrid amorphous resin in the total binder resin is preferably 60% by mass or more and 98% by mass or less, more preferably 65% ​​by mass or more and 95% by mass or less, and even more preferably 70% by mass or more and 90% by mass or less.

[0071] The characteristics of the amorphous resin will be described. The characteristics of the amorphous resin will be described. The glass transition temperature (Tg) of the amorphous 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), more specifically, from the "extrapolated glass transition onset temperature" described in the method for determining glass transition temperature in JIS K 7121-1987 "Method for measuring transition temperature of plastics."

[0072] The weight average molecular weight (Mw) of the amorphous resin is preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less. The number average molecular weight (Mn) of the amorphous resin is preferably 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the amorphous resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less. The weight average molecular weight and number average molecular weight are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is performed using a Tosoh GPC HLC-8120GPC as the measuring device, a Tosoh TSKgel SuperHM-M (15 cm) column, and THF solvent. The weight average molecular weight and number average molecular weight are calculated from the measurement results using a molecular weight calibration curve created with a monodisperse polystyrene standard sample.

[0073] The crystalline resin will now be described. Examples of the crystalline resin include known crystalline resins such as crystalline polyester resins and crystalline vinyl resins (e.g., polyalkylene resins, long-chain alkyl (meth)acrylate resins, etc.) Among these, crystalline polyester resins are preferred from the viewpoints of the mechanical strength and low-temperature fixability of the toner.

[0074] Crystalline polyester resin The crystalline polyester resin may be, for example, a polycondensate of a polyvalent carboxylic acid and a polyhydric alcohol. As the crystalline polyester resin, a commercially available product or a synthesized product may be used. Since the crystalline polyester resin easily forms a crystalline structure, a polycondensation product using a straight-chain aliphatic polymerizable monomer is preferable to a polymerizable monomer having an aromatic ring.

[0075] Examples of polyvalent carboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, etc.), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polyvalent carboxylic acid may be a trivalent or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the trivalent carboxylic acid include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), their anhydrides, and their lower (e.g., carbon number 1 to 5) alkyl esters. As the polybasic carboxylic acid, a dicarboxylic acid having a sulfonic acid group and a dicarboxylic acid having an ethylenic double bond may be used in combination with these dicarboxylic acids. The polyvalent carboxylic acids may be used alone or in combination of two or more kinds.

[0076] Examples of polyhydric alcohols include aliphatic diols (for example, straight-chain aliphatic diols having 7 to 20 carbon atoms in the main chain). Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanedecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols. The polyhydric alcohol may be a trihydric or higher alcohol having a crosslinked or branched structure in combination with the diol. Examples of the trihydric or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. The polyhydric alcohols may be used alone or in combination of two or more kinds.

[0077] The polyhydric alcohol may have an aliphatic diol content of 80 mol % or more, and preferably 90 mol % or more.

[0078] The crystalline polyester resin can be obtained, for example, by a known production method, like the amorphous polyester resin.

[0079] As the crystalline polyester resin, a polymer of an α,ω-straight-chain aliphatic dicarboxylic acid and an α,ω-straight-chain aliphatic diol is preferable. The polymer of α,ω-linear aliphatic dicarboxylic acid and α,ω-linear aliphatic diol has high compatibility with amorphous polyester resin, so it is difficult to inhibit the dispersibility of the colorant when fixing the toner. Therefore, the dispersibility of the colorant in the image after fixing is good. As a result, the color gamut of the secondary color image is improved.

[0080] The α,ω-linear aliphatic dicarboxylic acid is preferably an α,ω-linear aliphatic dicarboxylic acid in which the alkylene group connecting the two carboxy groups has 3 or more and 14 or less carbon atoms, more preferably the alkylene group has 4 or more and 12 or less carbon atoms, and even more preferably the alkylene group has 6 or more and 10 or less carbon atoms. Examples of α,ω-linear aliphatic dicarboxylic acids include succinic acid, glutaric acid, adipic acid, 1,6-hexanedicarboxylic acid (commonly known as suberic acid), 1,7-heptanedicarboxylic acid (commonly known as azelaic acid), 1,8-octanedicarboxylic acid (commonly known as sebacic acid), 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, and 1,18-octadecanedicarboxylic acid. Of these, 1,6-hexanedicarboxylic acid, 1,7-heptanedicarboxylic acid, 1,8-octanedicarboxylic acid, and 1,10-decanedicarboxylic acid are preferred. The α,ω-linear aliphatic dicarboxylic acids may be used alone or in combination of two or more kinds.

[0081] The α,ω-linear aliphatic diol is preferably an α,ω-linear aliphatic diol in which the alkylene group connecting the two hydroxy groups has 3 to 14 carbon atoms, more preferably the alkylene group has 4 to 12 carbon atoms, and further preferably the alkylene group has 6 to 10 carbon atoms. Examples of the α,ω-linear aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, and 1,18-octadecanediol. Of these, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred. The α,ω-linear aliphatic diols may be used alone or in combination of two or more kinds.

[0082] As the polymer of an α,ω-linear aliphatic dicarboxylic acid and an α,ω-linear aliphatic diol, from the viewpoint of improving the color gamut of a secondary color image, a polymer of at least one selected from the group consisting of 1,6-hexanedicarboxylic acid, 1,7-heptanedicarboxylic acid, 1,8-octanedicarboxylic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid and at least one selected from the group consisting of 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol is preferred, and among these, a polymer of 1,10-decanedicarboxylic acid and 1,6-hexanediol is more preferred.

[0083] The proportion of the crystalline polyester resin in the total binder resin is preferably from 1% by mass to 20% by mass, more preferably from 2% by mass to 15% by mass, and even more preferably from 3% by mass to 10% by mass. The characteristics of the crystalline resin will be described. The melting temperature of the crystalline resin is preferably 50°C or higher and 100°C or lower, more preferably 55°C or higher and 90°C or lower, and even more preferably 60°C or higher and 85°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) based on the "melting peak temperature" described in the method for determining melting temperature in JIS K7121-1987 "Method for measuring transition temperature of plastics."

[0084] The weight average molecular weight (Mw) of the crystalline resin is preferably 6,000 or more and 35,000 or less.

[0085] The content of the binder resin is preferably from 40% by mass to 95% by mass, more preferably from 50% by mass to 90% by mass, and even more preferably from 60% by mass to 85% by mass, based on the total mass of the toner particles.

[0086] -Coloring agent- Examples of colorants include carbon black, chrome yellow, Hansa Yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, Balkan orange, watch young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, lithol red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, Examples of the dyes include pigments such as ultramarine blue, chalcoil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate; and dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes. The colorant may be used alone or in combination of two or more kinds.

[0087] Among these, the pigment is preferable as the colorant. S and the net strength N of the alkali metals and alkaline earth metals ABy controlling the amount of pigment and improving the dispersibility of the pigment, the color gamut of the secondary color image is also improved.

[0088] The colorant may be surface-treated as necessary, or may be used in combination with a dispersant. In addition, a plurality of types of colorants may be used in combination.

[0089] The content of the colorant is preferably from 1% by mass to 30% by mass, and more preferably from 3% by mass to 15% by mass, based on the total mass of the toner particles.

[0090] -Release agent- The release agent exists in the form of domains in the toner particles, and the domain regions of the release agent are regions in which the colorant is difficult to disperse, limiting the regions in the toner particles in which the colorant is dispersed. Therefore, when the toner particles contain a crystalline resin (particularly a crystalline polyester resin), the color gamut of the secondary color image is likely to decrease. However, the net strength of sulfur N S and the net strength N of the alkali metals and alkaline earth metals A By controlling the above, even if the area in the toner particles where the colorant is dispersed is limited, the dispersibility of the colorant is increased, and therefore, a decrease in the color gamut of the secondary color image caused by the inclusion of a release agent in the toner particles is suppressed.

[0091] Examples of the release agent include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic or mineral / petroleum waxes such as montan wax, and ester waxes such as fatty acid esters and montan acid esters. The release agent is not limited to these.

[0092] As the releasing agent, an ester wax is preferable, and an ester wax of a higher fatty acid having 10 to 30 carbon atoms and a monovalent or polyvalent alcohol having 1 to 30 carbon atoms is more preferable. Ester wax has high compatibility with amorphous polyester resin, so it is difficult to inhibit the dispersibility of colorants when fixing the toner. Therefore, the dispersibility of colorants in the fixed image is improved. As a result, the color gamut of the secondary color image is improved.

[0093] Examples of ester waxes include ester compounds of higher fatty acids having 10 or more carbon atoms and monovalent or polyvalent aliphatic alcohols having 8 or more carbon atoms, and having a melting temperature of 60°C or higher and 110°C or lower (preferably 65°C or higher and 100°C or lower, more preferably 70°C or higher and 95°C or lower). Examples of ester waxes include ester compounds of higher fatty acids (caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, etc.) and alcohols (monohydric alcohols such as methanol, ethanol, propanol, isopropanol, butanol, capryl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, etc.; polyhydric alcohols such as glycerin, ethylene glycol, propylene glycol, sorbitol, pentaerythritol, etc.). Specific examples include carnauba wax, rice wax, candelilla wax, jojoba oil, Japan wax, beeswax, privet wax, lanolin, and montanic acid ester wax.

[0094] The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, and more preferably 60°C or higher and 100°C or lower. The melting temperature of the release agent is determined from a DSC curve obtained by differential scanning calorimetry (DSC) based on the "melting peak temperature" described in the method for determining melting temperature in JIS K7121:1987 "Method for measuring transition temperature of plastics."

[0095] The content of the release agent is preferably from 1% by mass to 20% by mass, and more preferably from 5% by mass to 15% by mass, based on the total mass of the toner particles.

[0096] -Other additives- Examples of other additives include known additives such as magnetic materials, charge control agents, inorganic powders, etc. These additives are contained in the toner particles as internal additives.

[0097] -Characteristics of toner particles- When the toner particles contain at least one of a crystalline resin (particularly a crystalline polyester resin) and a release agent for the purpose of imparting low-temperature fixing property and releasability, the crystalline resin (particularly a crystalline polyester resin) and the release agent exist in the toner particles in the form of domains. The domain regions of the crystalline resin and the release agent become regions in which the colorant is difficult to disperse, and the regions in the toner particles in which the colorant is dispersed are limited. Therefore, when the toner particles contain at least one of a crystalline resin (particularly a crystalline polyester resin) and a release agent, the color gamut of the secondary color image is likely to decrease. However, the net strength of sulfur N S and the net strength N of the alkali metals and alkaline earth metals A By controlling the above, even if the area in the toner particles where the colorant is dispersed is limited, the dispersibility of the colorant is increased, and therefore, a decrease in the color gamut of the secondary color image caused by the toner particles containing at least one of a crystalline resin (particularly a crystalline polyester resin) and a release agent is suppressed.

[0098] Specifically, when observing the cross section of a toner particle, even if the area ratio of the colorant dispersion region in the cross section of the toner particle is limited to, for example, 55% or more and 97% or less, 60% or more and 95% or less, or 60% or more and 80% or less, a decrease in the color gamut of the secondary color image is suppressed and the color gamut is improved.

[0099] Here, the colorant dispersion region is a region excluding the domains of the crystalline resin and the release agent in the cross section of the toner particle. The area ratio of the colorant dispersion region is measured as follows.

[0100] Toner particles (or toner particles with external additives) are mixed and embedded in epoxy resin, and the epoxy resin is solidified. The solidified material obtained is cut using an ultramicrotome device (Ultracut UCT manufactured by Leica) to prepare a thin section sample with a thickness of 80 nm to 130 nm. Next, the obtained thin section sample is stained with ruthenium tetroxide for 3 hours in a desiccator at 30°C. Then, an ultra-high resolution field emission scanning electron microscope (FE-SEM, S-4800 manufactured by Hitachi High-Technologies Corporation) is used to obtain a STEM observation image (accelerating voltage: 30 kV, magnification: 20,000 times) in the transmission image mode of the stained thin section sample. Among the toner particles, the crystalline polyester resin and the release agent are judged from the contrast and shape. In the SEM image, the crystalline resin stained with ruthenium is different from the amorphous resin, the release agent, etc., in that the binder resin other than the release agent has many double bond parts and is stained with ruthenium tetroxide, so the release agent part and the resin part other than the release agent can be distinguished. In other words, the release agent is the domain that is dyed the lightest with ruthenium, followed by the crystalline resin (e.g., crystalline polyester resin). is dyed, with the amorphous resin (for example, amorphous polyester resin) being dyed the darkest. By adjusting the contrast, it is possible to distinguish the domains in which the release agent appears white, the amorphous resin appears black, and the crystalline resin appears light gray.

[0101] The areas of the crystalline resin and release agent regions are then subjected to image analysis, and the areas of the crystalline resin and release agent regions are subtracted from the cross-sectional area of ​​the toner particle to obtain the area of ​​the colorant dispersion region. The area ratio of the colorant dispersion region is then calculated from the formula: Area ratio of colorant dispersion region (%) = Area of ​​colorant dispersion region / Cross-sectional area of ​​toner particle x 100. The "area ratio of the colorant dispersion region" is the average value for 50 toner particles.

[0102] The toner particles may be toner particles having a single layer structure, or may be toner particles having a so-called core-shell structure composed of a core portion (core particle) and a coating layer (shell layer) that coats the core portion. The toner particles having a core-shell structure may be composed of, for example, a core containing a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing the binder resin.

[0103] The volume average particle size (D50v) of the toner particles is preferably from 2 μm to 10 μm, and more preferably from 4 μm to 8 μm.

[0104] The various average particle sizes and particle size distribution indexes of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter, Inc.), and the electrolyte is measured using an ISOTON-II (manufactured by Beckman Coulter, Inc.). For the measurement, 0.5 mg to 50 mg of the measurement sample is added to 2 ml of a 5 mass % aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant, and this is then added to 100 ml to 150 ml of the electrolyte. The electrolyte with the sample suspended in it is dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles with diameters in the range of 2 μm to 60 μm is measured using a Coulter Multisizer II with an aperture diameter of 100 μm. The number of particles sampled is 50,000. Based on the measured particle size distribution, cumulative distributions of volume and number are drawn for each divided particle size range (channel) from the small diameter side, and the particle size at 16% of the cumulative size is defined as the volume particle size D16v, the number particle size D16p, the particle size at 50% of the cumulative size as the volume average particle size D50v, the cumulative number average particle size D50p, and the particle size at 84% of the cumulative size as the volume particle size D84v and number particle size D84p. Using these, the volumetric particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 The number size distribution index (GSDp) is (D84p / D16p) 1 / 2 It is calculated as:

[0105] The average circularity of the toner particles is preferably 0.94 or more and 1.00 or less, and more preferably 0.95 or more and 0.98 or less.

[0106] The average circularity of toner particles is calculated by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle having the same projected area as the particle image) / (perimeter of the particle projected image)]. Specifically, it is a value measured by the following method. The toner particles to be measured are sucked and collected, flattened, and instantly strobed to capture a still image of the particles, which is then analyzed by a flow-type particle image analyzer (FPIA-3000, manufactured by Sysmex Corporation). The number of samples to be taken when calculating the average circularity is 3,500. When the toner contains an external additive, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additive has been removed.

[0107] [External additives] Examples of the external additive include inorganic particles. Examples of inorganic particles include SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, and K2O·(TiO2). n , Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.

[0108] The surface of the inorganic particles as an external additive may be hydrophobized. The hydrophobization may be performed, for example, by immersing the inorganic particles in a hydrophobizing agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, and aluminum coupling agents. These may be used alone or in combination of two or more. The amount of the hydrophobizing agent is usually, for example, 1 to 10 parts by mass relative to 100 parts by mass of the inorganic particles.

[0109] Examples of external additives include resin particles (resin particles such as polystyrene, polymethyl methacrylate, and melamine resin), cleaning agents (for example, metal salts of higher fatty acids such as zinc stearate, and fluorine-based polymer particles), and the like.

[0110] The amount of the external additive is preferably from 0.01% by mass to 5% by mass, and more preferably from 0.01% by mass to 2.0% by mass, based on the toner particles.

[0111] [Toner manufacturing method] The toner according to the exemplary embodiment is obtained by producing toner particles and then externally adding an external additive to the toner particles.

[0112] The toner particles may be produced by any of a dry production method (e.g., a kneading and pulverizing method, etc.) and a wet production method (e.g., an aggregation and coalescence method, a suspension polymerization method, a dissolution suspension method, etc.). There is no particular limitation on these production methods, and any known production method may be used. Among these, it is preferable to obtain the toner particles by the aggregation and coalescence method.

[0113] Specifically, for example, when toner particles are produced by the aggregation and coalescence method, The toner particles are manufactured through a process including a step of preparing a resin particle dispersion in which resin particles to be a binder resin are dispersed (resin particle dispersion preparation process), a step of aggregating the resin particles (or other particles, if necessary) in the resin particle dispersion (in a dispersion after mixing other particle dispersions, if necessary) to form aggregated particles (aggregated particle formation process), and a step of heating the aggregated particle dispersion in which the aggregated particles are dispersed, fusing and coalescing the aggregated particles, and forming toner particles (fusion and coalescence process).

[0114] Here, in order to set the net intensity of each of the above elements in the toner particles within the above range, a source of each of the above elements is added during the production process of the toner particles.

[0115] Each step will be described in detail below. In the following description, a method for obtaining toner particles containing a colorant and a release agent will be described, but the colorant and the release agent are used as necessary. Of course, additives other than the colorant and the release agent may be used.

[0116] -Resin particle dispersion preparation process- First, a resin particle dispersion in which resin particles serving as a binder resin are dispersed, as well as a colorant particle dispersion in which colorant particles are dispersed and a release agent particle dispersion in which release agent particles are dispersed are prepared.

[0117] Here, the resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium with the aid of a surfactant.

[0118] The dispersion medium used in the resin particle dispersion liquid is, for example, an aqueous medium. Examples of the aqueous medium include water such as distilled water and ion-exchanged water, alcohols, etc. These may be used alone or in combination of two or more.

[0119] Examples of the surfactant include anionic surfactants such as sulfate salts, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly preferred. The nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants. The surfactant may be used alone or in combination of two or more kinds.

[0120] In the resin particle dispersion, examples of the method for dispersing the resin particles in the dispersion medium include general dispersion methods using, for example, a rotary shear type homogenizer, a ball mill having a media, a sand mill, a dyno mill, etc. Depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion using, for example, a phase inversion emulsification method. The phase inversion emulsification method is a method in which the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, a base is added to the organic continuous phase (O phase) to neutralize it, and then an aqueous medium (W phase) is added to effect conversion of the resin from W / O to O / W (so-called phase inversion), resulting in a discontinuous phase, and the resin is dispersed in particulate form in the aqueous medium.

[0121] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably from 0.01 μm to 1 μm, more preferably from 0.08 μm to 0.8 μm, and even more preferably from 0.1 μm to 0.6 μm. The volume average particle size of the resin particles is measured by using a particle size distribution obtained by measurement using a laser diffraction particle size distribution measuring device (e.g., LA-700 manufactured by Horiba, Ltd.), subtracting the cumulative distribution from the small particle size side for the volume of the divided particle size range (channel), and measuring the particle size at which the cumulative distribution is 50% of all particles as the volume average particle size D50v. The volume average particle sizes of particles in other dispersions are also measured in the same manner.

[0122] The content of the resin particles in the resin particle dispersion is, for example, preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass.

[0123] In addition, for example, a colorant particle dispersion and a release agent particle dispersion are also prepared in the same manner as the resin particle dispersion. That is, the volume average particle size, dispersion medium, dispersion method, and particle content of the particles in the resin particle dispersion are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0124] -Agglomerated particle formation process- Next, the colorant particle dispersion and the release agent particle dispersion are mixed together with the resin particle dispersion. Then, in the mixed dispersion, the resin particles, the colorant particles, and the release agent particles are hetero-aggregated to form aggregated particles containing the resin particles, the colorant particles, and the release agent particles and having a diameter close to that of the target toner particles.

[0125] Specifically, for example, an aggregating agent is added to the mixed dispersion, the pH of the mixed dispersion is adjusted to be acidic (e.g., pH 2 or more and 5 or less), a dispersion stabilizer is added as necessary, and then the mixed dispersion is heated to a temperature of the glass transition temperature of the resin particles (specifically, for example, a temperature of the glass transition temperature of the resin particles -30°C or more and the glass transition temperature -10°C or less), and the particles dispersed in the mixed dispersion are aggregated to form aggregated particles. In the aggregated particle formation process, for example, the above-mentioned aggregating agent may be added to the mixed dispersion at room temperature (e.g., 25°C) while stirring the mixed dispersion with a rotary shear homogenizer, the pH of the mixed dispersion may be adjusted to an acidic state (e.g., pH 2 or more and 5 or less), and a dispersion stabilizer may be added as necessary, followed by the above-mentioned heating.

[0126] Examples of the flocculant include a surfactant having a polarity opposite to that of the surfactant used as the dispersant added to the mixed dispersion, an inorganic metal salt, and a divalent or higher metal complex. In particular, when a metal complex is used as the flocculant, the amount of 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 ions of the flocculant may be used, and a chelating agent is preferably used as this additive.

[0127] 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, as well as inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. The chelating agent may be a water-soluble chelating agent, such as oxycarboxylic acid (e.g., tartaric acid, citric acid, gluconic acid, etc.), iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), etc. The amount of the chelating agent added is, for example, 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, relative to 100 parts by mass of the resin particles.

[0128] -Fusion / coalescence process- Next, the aggregated particle dispersion liquid in which the aggregated particles are dispersed is heated, for example, to a temperature equal to or higher than the glass transition temperature of the resin particles (for example, a temperature 10 to 30° C. higher than the glass transition temperature of the resin particles) to fuse and coalesce the aggregated particles, thereby forming toner particles.

[0129] Through the above steps, toner particles are obtained. Note that, after obtaining an aggregated particle dispersion liquid in which aggregated particles are dispersed, the toner particles may be manufactured through a process of further mixing the aggregated particle dispersion liquid with a resin particle dispersion liquid in which resin particles are dispersed, and aggregating the aggregated particles so that the resin particles are further attached to the surfaces of the aggregated particles to form second aggregated particles, and a process of heating the second aggregated particle dispersion liquid in which the second aggregated particles are dispersed to fuse and coalesce the second aggregated particles to form toner particles having a core / shell structure.

[0130] After the fusion and coalescence process, the toner particles formed in the solution are subjected to a known washing process, solid-liquid separation process, and drying process to obtain toner particles in a dried state. In the washing step, it is preferable to carry out sufficient replacement washing with ion-exchanged water from the viewpoint of electrostatic charge. In addition, the solid-liquid separation step is not particularly limited, but it is preferable to carry out suction filtration, pressure filtration, etc. from the viewpoint of productivity. In addition, in the drying step, there is no particular limit to the method, but it is preferable to carry out freeze drying, air flow drying, fluidized drying, vibration type fluidized drying, etc. from the viewpoint of productivity.

[0131] The toner according to the present embodiment is produced, for example, by adding an external additive to the obtained toner particles in a dry state and mixing them. The mixing may be performed, for example, by using a V blender, a Henschel mixer, a Loedige mixer, etc. Furthermore, if necessary, coarse particles of the toner may be removed using a vibration sieve, an air sieve, etc.

[0132] <Electrostatic image developer> The electrostatic image developer according to this embodiment contains at least the toner according to this embodiment. The electrostatic image developer according to the present embodiment may be a one-component developer containing only the toner according to the present embodiment, or may be a two-component developer in which the toner is mixed with a carrier.

[0133] The carrier is not particularly limited, and may be any known carrier, such as a coated carrier in which the surface of a core material 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, or a resin impregnated type carrier in which porous magnetic powder is impregnated with a resin. The magnetic powder dispersion type carrier and the resin impregnated type carrier may be a carrier in which the constituent particles of the carrier are used as a core material and are coated with a coating resin.

[0134] Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0135] 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 ester copolymer, straight silicone resin containing an organosiloxane bond or a modified product thereof, fluororesin, polyester, polycarbonate, phenolic resin, and epoxy resin. The coating resin and the matrix resin may contain other additives such as conductive particles. 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.

[0136] Here, in order to coat the surface of the core material with a coating resin, a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent can be mentioned. The solvent is not particularly limited and may be selected taking into consideration the coating resin to be used, the suitability for application, etc. Specific resin coating methods include an immersion method in which the core material is immersed in a solution for forming a coating layer, a spray method in which the solution for forming a coating layer is sprayed onto the surface of the core material, a fluidized bed method in which the solution for forming a coating layer is sprayed onto the core material while it is suspended in flowing air, and a kneader coater method in which the core material of a carrier and the solution for forming a coating layer are mixed in a kneader coater and the solvent is removed.

[0137] In the two-component developer, the mixture ratio (mass ratio) of the toner and the carrier is preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100.

[0138] <Image forming device / image forming method> An image forming apparatus / image forming method according to this embodiment will be described. The image forming apparatus according to the present embodiment includes an image carrier, a charging means for charging the surface of the image carrier, an electrostatic image forming means for forming an electrostatic image on the surface of the charged image carrier, a developing means for containing an electrostatic image developer and developing the electrostatic image formed on the surface of the image carrier as a toner image with the electrostatic image developer, a transfer means for transferring the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing means for fixing the toner image transferred to the surface of the recording medium. The electrostatic image developer according to the present embodiment is used as the electrostatic image developer.

[0139] In the image forming apparatus according to this embodiment, an image forming method (the image forming method according to this embodiment) is carried out, which includes a charging step of charging the surface of an image carrier, an electrostatic image forming step of forming an electrostatic image on the surface of the charged image carrier, a developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer according to this embodiment, a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0140] The image forming apparatus according to the present embodiment may be any of known image forming apparatuses, such as a direct transfer type apparatus in which a toner image formed on the surface of an image holder is directly transferred to a recording medium; an intermediate transfer type apparatus in which a toner image formed on the surface of an image holder is primarily transferred to the surface of an intermediate transfer body, and the toner image transferred to the surface of the intermediate transfer body is then secondarily transferred to the surface of a recording medium; an apparatus equipped with a cleaning means for cleaning the surface of the image holder before charging after the transfer of the toner image; and an apparatus equipped with a discharging means for irradiating the surface of the image holder with discharging light to discharge it before charging after the transfer of the toner image. In the case of an intermediate transfer type device, the transfer means has, for example, an intermediate transfer body onto whose surface a toner image is transferred, a primary transfer means which primarily transfers the toner image formed on the surface of the image carrier onto the surface of the intermediate transfer body, and a secondary transfer means which secondarily transfers the toner image transferred onto the surface of the intermediate transfer body onto the surface of a recording medium.

[0141] In the image forming apparatus according to the present embodiment, for example, a portion including the developing means may have a cartridge structure (process cartridge) that is detachably attached to the image forming apparatus. As the process cartridge, for example, a process cartridge including a developing means that contains the electrostatic image developer according to the present embodiment is preferably used.

[0142] An example of an image forming apparatus according to the present embodiment will be described below, but the present invention is not limited to this. Note that only the main parts shown in the drawings will be described, and descriptions of the rest will be omitted.

[0143] FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus according to the present embodiment. The image forming apparatus shown in Fig. 1 includes first to fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming means) that output images of each color of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter sometimes simply referred to as "units") 10Y, 10M, 10C, and 10K are arranged in parallel at predetermined distances from each other in the horizontal direction. These units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the image forming apparatus.

[0144] Above each of the units 10Y, 10M, 10C, and 10K in the drawing, an intermediate transfer belt 20 is provided as an intermediate transfer body extending through each unit. The intermediate transfer belt 20 is provided wound around a drive roll 22 and a support roll 24 that are arranged from left to right in the drawing at a distance from each other and contact the inner surface of the intermediate transfer belt 20, and is adapted to run in a direction from the first unit 10Y to the fourth unit 10K. Note that a force is applied to the support roll 24 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 them. In addition, an intermediate transfer body cleaning device 30 is provided on the image carrier side of the intermediate transfer belt 20, facing the drive roll 22. Further, the developing devices (developing means) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K are supplied with toner including four colors of toner, yellow, magenta, cyan, and black, contained in toner cartridges 8Y, 8M, 8C, and 8K, respectively.

[0145] Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, the first unit 10Y that forms a yellow image and is disposed upstream in the direction in which the intermediate transfer belt travels will be described here as a representative example. Note that by assigning reference numerals of magenta (M), cyan (C), and black (K) instead of yellow (Y) to parts equivalent to those of the first unit 10Y, descriptions of the second to fourth units 10M, 10C, and 10K will be omitted.

[0146] The first unit 10Y has a photoconductor 1Y that acts as an image carrier. Around the photoconductor 1Y, a charging roll (an example of a charging means) 2Y that charges the surface of the photoconductor 1Y to a predetermined potential, an exposure device (an example of an electrostatic image forming means) 3 that exposes the charged surface to a laser beam 3Y based on a color-separated image signal to form an electrostatic image, a developing device (an example of a developing means) 4Y that supplies charged toner to the electrostatic image to develop it, a primary transfer roll 5Y (an example of a primary transfer means) that transfers the developed toner image onto an intermediate transfer belt 20, and a photoconductor cleaning device (an example of a cleaning means) 6Y that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer are arranged in this order. The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20 and is provided at a position facing the photoconductor 1Y. Furthermore, a bias power supply (not shown) that applies a primary transfer bias is connected to each of the primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power supply varies the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

[0147] Hereinafter, an operation of forming a yellow image in first unit 10Y will be described. First, prior to operation, the surface of the photoconductor 1Y is charged to a potential of −600V to −800V by the charging roll 2Y. The photoconductor 1Y has a conductivity (for example, a volume resistivity at 20° C. of 1×10 -6The photosensitive layer is formed by laminating a photosensitive layer on a substrate having a resistivity of Ωcm or less. This photosensitive layer is usually highly resistive (the resistance of ordinary resins), but when irradiated with a laser beam 3Y, the resistivity of the portion irradiated with the laser beam changes. A laser beam 3Y is output to the charged surface of the photoreceptor 1Y via an exposure device 3 in accordance with image data for yellow sent from a control unit (not shown). The laser beam 3Y is irradiated onto the photosensitive layer on the surface of the photoreceptor 1Y, and an electrostatic charge image of a yellow image pattern is formed on the surface of the photoreceptor 1Y.

[0148] An electrostatic image is an image formed on the surface of the photoconductor 1Y by electrostatic charging. The laser beam 3Y reduces the resistivity of the irradiated parts of the photosensitive layer, causing the charged charges on the surface of the photoconductor 1Y to flow, while the charges remain in the parts not irradiated by the laser beam 3Y. This is a so-called negative latent image. The electrostatic image formed on the photoconductor 1Y is rotated to a predetermined developing position as the photoconductor 1Y travels. Then, at this developing position, the electrostatic image on the photoconductor 1Y is made visible as a toner image (developed image) by the developing device 4Y.

[0149] The developing device 4Y contains an electrostatic image developer including at least yellow toner and a carrier, for example. The yellow toner is triboelectrically charged by being stirred inside the developing device 4Y, and is held on a developer roll (an example of a developer holder) with a charge of the same polarity (negative polarity) as the charge on the photoconductor 1Y. As the surface of the photoconductor 1Y passes through the developing device 4Y, the yellow toner electrostatically adheres to the discharged latent image portion on the surface of the photoconductor 1Y, and the latent image is developed with the yellow toner. The photoconductor 1Y on which the yellow toner image has been formed continues to travel at a predetermined speed, and the toner image developed on the photoconductor 1Y is transported to a predetermined primary transfer position.

[0150] When the yellow toner image on the photoreceptor 1Y is transported 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 acts on the toner image, and the toner image on the photoreceptor 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 in the first unit 10Y, for example, it is controlled to +10 μA by a control unit (not shown). On the other hand, the toner remaining on the photoconductor 1Y is removed and collected by the photoconductor cleaning device 6Y.

[0151] Further, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K subsequent to the second unit 10M is also controlled in accordance with the first unit. In this manner, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is conveyed successively through the second to fourth units 10M, 10C, and 10K, where the toner images of the respective colors are transferred in a superimposed manner.

[0152] The intermediate transfer belt 20 onto which the four color toner images have been transferred in multiple layers through the first to fourth units reaches a secondary transfer section that is composed of the intermediate transfer belt 20, a support roll 24 that contacts the inner surface of the intermediate transfer belt, and a secondary transfer roll (an example of a secondary transfer means) 26 arranged on the image bearing surface side of the intermediate transfer belt 20. Meanwhile, a recording paper (an example of a recording medium) P is fed at a predetermined timing into the gap between the secondary transfer roll 26 and the intermediate transfer belt 20 via a supply mechanism, and a secondary transfer bias is applied to the support roll 24. The transfer bias applied at this time has a (-) polarity that is the same as the (-) polarity of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, so that the toner image on the intermediate transfer belt 20 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) that detects the resistance of the secondary transfer section, and is voltage-controlled.

[0153] Thereafter, the recording paper P is sent to a pressure contact portion (nip portion) of a pair of fixing rolls in a fixing device (one example of a fixing means) 28, where the toner image is fixed onto the recording paper P, forming a fixed image.

[0154] The recording paper P onto which the toner image is transferred can be, for example, plain paper used in electrophotographic copying machines, printers, etc. In addition to the recording paper P, other examples of the recording medium include overhead projector sheets, etc. To further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper P is also smooth. For example, coated paper in which the surface of ordinary paper is coated with resin or the like, art paper for printing, etc. are preferably used.

[0155] After the color image has been fixed, the recording paper P is conveyed toward the discharge section, and the series of color image forming operations is completed.

[0156] <Process cartridge / toner cartridge> The process cartridge according to this embodiment will be described. The process cartridge according to this embodiment is a process cartridge that contains the electrostatic image developer according to this embodiment, is equipped with a developing means that develops an electrostatic image formed on the surface of an image carrier using the electrostatic image developer into a toner image, and is detachably attached to an image forming apparatus.

[0157] In addition, the process cartridge according to this embodiment is not limited to the above configuration, and may be configured to include a developing device and, as necessary, at least one other means selected from an image carrier, a charging means, an electrostatic image forming means, and a transfer means.

[0158] An example of a process cartridge according to the present embodiment will be described below, but the present invention is not limited to this example. Note that only the main parts shown in the drawings will be described, and descriptions of the rest will be omitted.

[0159] FIG. 2 is a schematic diagram showing the process cartridge according to the present embodiment. The process cartridge 200 shown in FIG. 2 is configured by, for example, a housing 117 having a mounting rail 116 and an opening 118 for exposure, and integrally combining and holding a photoconductor 107 (an example of an image carrier), a charging roll 108 (an example of a charging means) provided around the photoconductor 107, a developing device 111 (an example of a developing means), and a photoconductor cleaning device 113 (an example of a cleaning means), which are assembled into a cartridge. In FIG. 2, 109 denotes an exposure device (an example of an electrostatic image forming means), 112 denotes a transfer device (an example of a transfer means), 115 denotes a fixing device (an example of a fixing means), and 300 denotes recording paper (an example of a recording medium).

[0160] Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to the present embodiment is a toner cartridge that contains the toner according to the present embodiment and is detachably attached to an image forming apparatus. The toner cartridge contains replenishment toner to be supplied to a developing unit provided in the image forming apparatus.

[0161] 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K can be attached and detached, and the developing devices 4Y, 4M, 4C, and 4K are connected to the toner cartridges corresponding to the respective developing devices (colors) through toner supply pipes (not shown). When the toner contained in the toner cartridge becomes low, the toner cartridge is replaced. EXAMPLES

[0162] Hereinafter, the embodiments of the present invention will be described in detail with reference to examples, but the embodiments of the present invention are not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" are based on mass.

[0163] <Synthesis of amorphous polyester resin (A)> Terephthalic acid: 68 parts Fumaric acid: 32 parts Ethylene glycol: 42 parts 1,5-Pentanediol: 47 parts The above materials were placed in a flask equipped with a stirrer, a nitrogen inlet tube, a temperature sensor, and a distillation column, and the temperature was raised to 220°C over 1 hour under a nitrogen gas flow, and 1 part of titanium tetraethoxide was added for a total of 100 parts of the above materials. The temperature was raised to 240°C over 0.5 hours while distilling off the generated water, and the dehydration condensation reaction was continued at 240°C for 1 hour, after which the reaction product was cooled. In this way, an amorphous polyester resin (A) with a weight average molecular weight of 97,000 and a glass transition temperature of 60°C was obtained.

[0164] <Preparation of amorphous polyester resin particle dispersion (A1)> In a vessel equipped with a temperature control means and a nitrogen substitution means, 40 parts of ethyl acetate and 25 parts of 2-butanol were added to prepare a mixed solvent, and then 100 parts of amorphous polyester resin were gradually added and dissolved, and 10% aqueous ammonia solution (equivalent to 3 times the amount by molar ratio relative to the acid value of the resin) was added thereto and stirred for 30 minutes. Next, the inside of the vessel was substituted with dry nitrogen, the temperature was kept at 40°C, and 400 parts of ion-exchanged water was dropped into the mixed liquid while stirring, to perform emulsification. After the dropwise addition, the emulsion was returned to 25°C, and a resin particle dispersion in which resin particles with a volume average particle size of 195 nm were dispersed was obtained. Ion-exchanged water was added to this resin particle dispersion to adjust the solid content to 20%, and an amorphous polyester resin particle dispersion (A1) was obtained.

[0165] <Preparation of cyan colorant-containing amorphous polyester resin particle dispersion (C1)> 250 parts of amorphous polyester resin (A) and 50 parts of CI Pigment Blue 15:3 (phthalocyanine pigment, Dainichi Seika Kabushiki Kaisha, Cyanine Blue 4937) were put into a Henschel mixer and mixed for 120 seconds at a screw rotation speed of 600 rpm to obtain raw material (A). 200 parts of raw material (A) and 0.2 parts of 50% aqueous sodium hydroxide solution were put into the raw material inlet of a twin-screw extruder (TEM-58SS, Toshiba Machine Co., Ltd.), and 40 parts of anionic surfactant (TaycaPower, Tayca Co., Ltd., solid content 12%, sodium dodecylbenzenesulfonate) were put into the fourth barrel of the twin-screw extruder, and kneaded at a barrel setting temperature of 95°C and a screw rotation speed of 240 rpm. 150 parts of ion-exchanged water at a temperature of 95°C was fed from the fifth barrel of the twin-screw extruder, 150 parts by mass of ion-exchanged water at a temperature of 95°C from the seventh barrel, and 15 parts of ion-exchanged water at a temperature of 95°C from the ninth barrel, and the raw material (A) was kneaded at an average feed rate of 200 kg / h to obtain a resin particle dispersion in which resin particles with a volume average particle size of 180 nm were dispersed. Ion-exchanged water was added to this resin particle dispersion to adjust the solid content to 20%, and a cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C1) was obtained.

[0166] <Preparation of Magenta Colorant-Containing Amorphous Polyester Resin Particle Dispersion (M1)> A magenta colorant (CI Pigment Red 269)-containing amorphous polyester resin particle dispersion (M1) was obtained in the same manner as the cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C1), except that the colorant was changed from CI Pigment Blue 15:3 to CI Pigment Red 269 (quinacridone pigment, manufactured by Nippon Ink Chemicals, SYMULER FAST RED 1022).

[0167] <Preparation of Yellow Colorant-Containing Amorphous Polyester Resin Particle Dispersion (Y1)> A yellow colorant (CI Pigment Yellow 74)-containing amorphous polyester resin particle dispersion (Y1) was obtained in the same manner as the cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C1), except that the colorant was changed from CI Pigment Blue 15:3 to CI Pigment Yellow 74 (monoazo pigment, Dainichi Seika Chemicals, Seika Fast Yellow 2054).

[0168] <Preparation of Black Colorant-Containing Amorphous Polyester Resin Particle Dispersion (K1)> A black colorant (carbon black)-containing amorphous polyester resin particle dispersion (K1) was obtained in the same manner as the cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C1), except that the colorant was changed from CI Pigment Blue 15:3 to carbon black (Regal 330, manufactured by Cabot Corporation).

[0169] <Preparation of amorphous polyester resin particle dispersions containing various colorants (C2 / M2 / Y2 / K2)> The following various colorant-containing amorphous polyester resin particle dispersions were obtained in the same manner as in the cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C1), except that the amount of anionic surfactant (TaycaPower, manufactured by Tayca Corporation, solid content 12%, sodium dodecylbenzenesulfonate) added to the fourth barrel of the twin-screw extruder was changed from 40 parts to 20 parts. Amorphous polyester resin particle dispersion (C2) containing cyan colorant (CI Pigment Blue 15:3) · Magenta colorant (CI Pigment Red 269)-containing amorphous polyester resin particle dispersion (M2) Amorphous polyester resin particle dispersion (Y2) containing yellow colorant (CI Pigment Yellow 74) A black colorant (carbon black)-containing amorphous polyester resin particle dispersion (K2) was obtained.

[0170] <Preparation of amorphous polyester resin particle dispersions containing various colorants (C3 / M3 / Y3 / K3)> The following various colorant-containing amorphous polyester resin particle dispersions were obtained in the same manner as in the cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C1), except that the amount of anionic surfactant (TaycaPower, manufactured by Tayca Corporation, solid content 12%, sodium dodecylbenzenesulfonate) added to the fourth barrel of the twin-screw extruder was changed from 40 parts to 60 parts. · Cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C3) · Magenta colorant (CI Pigment Red 269)-containing amorphous polyester resin particle dispersion (M3) Amorphous polyester resin particle dispersion (Y3) containing yellow colorant (CI Pigment Yellow 74) · Amorphous polyester resin particle dispersion containing black colorant (carbon black) (K3)

[0171] <Preparation of amorphous polyester resin particle dispersions containing various colorants (C4 / M4 / Y4 / K4)> The following various colorant-containing amorphous polyester resin particle dispersions were obtained in the same manner as in the cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C1), except that the amount of anionic surfactant (TaycaPower, manufactured by Tayca Corporation, solid content 12%, sodium dodecylbenzenesulfonate) added to the fourth barrel of the twin-screw extruder was changed from 40 parts to 5 parts. · Amorphous polyester resin particle dispersion (C4) containing cyan colorant (CI Pigment Blue 15:3) · Magenta colorant (CI Pigment Red 269)-containing amorphous polyester resin particle dispersion (M4) Amorphous polyester resin particle dispersion (Y4) containing yellow colorant (CI Pigment Yellow 74) · Amorphous polyester resin particle dispersion containing black colorant (carbon black) (K4)

[0172] <Preparation of amorphous polyester resin particle dispersions containing various colorants (C5 / M5 / Y5 / K5)> The following various colorant-containing amorphous polyester resin particle dispersions were obtained in the same manner as in the cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C1), except that the amount of anionic surfactant (TaycaPower, manufactured by Tayca Corporation, solid content 12%, sodium dodecylbenzenesulfonate) added from the fourth barrel of the twin-screw extruder was changed from 40 parts to 75 parts. · Amorphous polyester resin particle dispersion (C5) containing cyan colorant (CI Pigment Blue 15:3) · Magenta colorant (CI Pigment Red 269)-containing amorphous polyester resin particle dispersion (M5) - Amorphous polyester resin particle dispersion (Y5) containing yellow colorant (CI Pigment Yellow 74) A black colorant (carbon black)-containing amorphous polyester resin particle dispersion (K5) was obtained.

[0173] <Preparation of amorphous polyester resin particle dispersions containing various colorants (C6 / M6 / Y6 / K6)> The following various colorant-containing amorphous polyester resin particle dispersions were obtained in the same manner as in the cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C1), except that the amount of anionic surfactant (TaycaPower, manufactured by Tayca Corporation, solid content 12%, sodium dodecylbenzenesulfonate) added from the fourth barrel of the twin-screw extruder was changed from 40 parts to 25 parts. · Cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C6) · Magenta colorant (CI Pigment Red 269)-containing amorphous polyester resin particle dispersion (M6) Amorphous polyester resin particle dispersion (Y6) containing yellow colorant (CI Pigment Yellow 74) A black colorant (carbon black)-containing amorphous polyester resin particle dispersion (K6) was obtained.

[0174] <Preparation of amorphous polyester resin particle dispersions containing various colorants (C7 / M7 / Y7 / K7)> The following various colorant-containing amorphous polyester resin particle dispersions were obtained in the same manner as in the cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C1), except that the amount of anionic surfactant (TaycaPower, manufactured by Tayca Corporation, solid content 12%, sodium dodecylbenzenesulfonate) added from the fourth barrel of the twin-screw extruder was changed from 40 parts to 55 parts. · Cyan colorant (CI Pigment Blue 15:3)-containing amorphous polyester resin particle dispersion (C7) · Magenta colorant (CI Pigment Red 269)-containing amorphous polyester resin particle dispersion (M7) Amorphous polyester resin particle dispersion (Y7) containing yellow colorant (CI Pigment Yellow 74) A black colorant (carbon black)-containing amorphous polyester resin particle dispersion (K7) was obtained.

[0175] <Preparation of Crystalline Polyester Resin Particle Dispersion (B1)> 1,10-Decanedicarboxylic acid: 260 parts 1,6-Hexanediol: 167 parts Dibutyltin oxide (catalyst): 0.3 parts The above materials were placed in a heated and dried three-necked flask, the air in the three-necked flask was replaced with nitrogen gas to create an inert atmosphere, and the mixture was stirred and refluxed at 180°C for 5 hours by mechanical stirring. Next, the temperature was gradually raised to 230°C under reduced pressure and stirred for 2 hours, and when the mixture became viscous, it was air-cooled to stop the reaction. Thus, a crystalline polyester resin with a weight average molecular weight of 12500 and a melting temperature of 73°C was obtained. 90 parts of the crystalline polyester resin, 1.8 parts of anionic surfactant (TaycaPower, manufactured by Tayca Co., Ltd., solid content 12%, sodium dodecylbenzenesulfonate) and 210 parts of ion-exchanged water were mixed, heated to 120°C, and dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA Co., Ltd.), and then dispersed for 1 hour using a pressure discharge type Gaulin homogenizer to obtain a resin particle dispersion in which resin particles with a volume average particle size of 195 nm were dispersed. Ion-exchanged water was added to this resin particle dispersion to adjust the solid content to 20%, thereby obtaining a crystalline polyester resin particle dispersion (B1).

[0176] <Preparation of Crystalline Polyester Resin Particle Dispersion (B2)> 1,8-octanedicarboxylic acid: 260 parts 1,6-Hexanediol: 167 parts Dibutyltin oxide (catalyst): 0.3 parts The above materials were placed in a heated and dried three-necked flask, the air in the three-necked flask was replaced with nitrogen gas to create an inert atmosphere, and the mixture was stirred and refluxed at 180°C for 5 hours by mechanical stirring. Next, the temperature was gradually raised to 230°C under reduced pressure and stirred for 2 hours, and when the mixture became viscous, it was air-cooled to stop the reaction. Thus, a crystalline polyester resin with a weight average molecular weight of 12500 and a melting temperature of 73°C was obtained. 90 parts of the crystalline polyester resin, 1.8 parts of anionic surfactant (TaycaPower, manufactured by Tayca Co., Ltd., solid content 12%, sodium dodecylbenzenesulfonate) and 210 parts of ion-exchanged water were mixed, heated to 120°C, and dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA Co., Ltd.), and then dispersed for 1 hour using a pressure discharge type Gaulin homogenizer to obtain a resin particle dispersion in which resin particles with a volume average particle size of 195 nm were dispersed. Ion-exchanged water was added to this resin particle dispersion to adjust the solid content to 20%, thereby obtaining a crystalline polyester resin particle dispersion (B2).

[0177] <Preparation of styrene acrylic resin particle dispersion (S1)> Styrene: 375 parts n-Butyl acrylate: 25 parts Acrylic acid: 2 parts Dodecanethiol: 24 parts Carbon tetrabromide: 4 parts The mixture obtained by mixing and dissolving the above materials was dispersed and emulsified in a flask in a surfactant solution in which 6 parts of a nonionic surfactant (manufactured by Sanyo Chemical Industries, Nonipol 400) and 10 parts of an anionic surfactant (manufactured by TaycaPower, Tayca Co., Ltd., solid content 12%, sodium dodecylbenzenesulfonate) were dissolved in 550 parts of ion-exchanged water. Next, an aqueous solution in which 4 parts of ammonium persulfate were dissolved in 50 parts of ion-exchanged water was added over a period of 20 minutes while stirring the flask. Next, after nitrogen replacement, the flask was heated in an oil bath while stirring the contents until the temperature reached 70°C, and the temperature was maintained at 70°C for 5 hours to continue emulsion polymerization. Thus, a resin particle dispersion in which resin particles having a volume average particle size of 150 nm were dispersed was obtained. Ion-exchanged water was added to this resin particle dispersion to adjust the solid content to 20%, and a styrene acrylic resin particle dispersion (S1) was obtained.

[0178] <Preparation of hybrid resin (amorphous resin having amorphic polyester resin segments and a styrene acrylic resin segment) particle dispersion (SPE1)> The inside of a four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 5,670 parts of polyoxypropylene (2.2)-2,2-bis (4-hydroxyphenyl) propane, 585 parts of polyoxyethylene (2.0)-2,2-bis (4-hydroxyphenyl) propane, 2,450 parts of terephthalic acid, and 44 parts of tin (II) di (2-ethylhexanoate) were added. The mixture was heated to 235 ° C. under a nitrogen atmosphere while stirring, and maintained for 5 hours. The pressure in the flask was then further reduced and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190 ° C., 42 parts of fumaric acid and 207 parts of trimellitic acid were added, and the mixture was maintained at a temperature of 190 ° C. for 2 hours, and then heated to 210 ° C. over 2 hours. The pressure in the flask was further reduced and maintained at 8.0 kPa for 4 hours to obtain an amorphous polyester resin A (polyester segment). Next, 800 parts of amorphous polyester resin A was added to a four-neck flask equipped with a cooling tube, a stirrer, and a thermocouple, and the mixture was stirred at a stirring speed of 200 rpm under a nitrogen atmosphere. After that, 40 parts of styrene, 142 parts of ethyl acrylate, 16 parts of acrylic acid, 2 parts of 1,10-decanediol diacrylate, and 1000 parts of toluene were added as addition polymerizable monomers, and mixed for another 30 minutes. Furthermore, 6 parts of polyoxyethylene alkyl ether (nonionic surfactant, trade name: Emulgen 430, manufactured by Kao Corporation), 40 parts of a 15% aqueous sodium dodecylbenzenesulfonate solution (anionic surfactant, trade name: Neopelex G-15, manufactured by Kao Corporation) and 233 parts of 5% potassium hydroxide were added, and the mixture was heated to 95°C with stirring to melt, and mixed at 95°C for 2 hours to obtain a resin mixture solution. Next, while stirring the resin mixture solution, 1,145 parts of deionized water was added dropwise at a rate of 6 parts / min to obtain an emulsion. Next, the obtained emulsion was cooled to 25°C, passed through a 200-mesh wire screen, and deionized water was added to adjust the solid content to 30%, thereby obtaining a hybrid resin particle dispersion (SPE1). The content of styrene-derived structural units in the synthesized hybrid resin was 4 mass % relative to the total mass of the hybrid resin.

[0179] <Preparation of release agent particle dispersion (W1)> Ester wax (Nippon Oil & Fats Co., Ltd., WEP-8, melting temperature 79°C): 100 parts Anionic surfactant: 1 part (TaycaPower, manufactured by Tayca Corporation, sodium dodecylbenzenesulfonate) Ion-exchanged water: 350 parts The above materials were mixed and heated to 100°C, dispersed using a homogenizer (IKA Ultra Turrax T50), and then dispersed using a pressure discharge Gaulin homogenizer to obtain a release agent particle dispersion in which release agent particles with a volume average particle size of 220 nm were dispersed. Ion-exchanged water was added to this release agent particle dispersion to adjust the solid content to 20%, and this was used as release agent particle dispersion (W1).

[0180] <Preparation of release agent particle dispersion (W2)> Carnauba wax (Toa Kasei Co., Ltd., RC-160, melting temperature: 84°C): 100 parts Anionic surfactant: 1 part (TaycaPower, manufactured by Tayca Corporation, sodium dodecylbenzenesulfonate) Ion-exchanged water: 350 parts The above materials were mixed and heated to 100°C, dispersed using a homogenizer (IKA Ultra Turrax T50), and then dispersed using a pressure discharge Gaulin homogenizer to obtain a release agent particle dispersion in which release agent particles with a volume average particle size of 220 nm were dispersed. Ion-exchanged water was added to this release agent particle dispersion to adjust the solid content to 20%, and this was used as release agent particle dispersion (W2).

[0181] <Example 1> [Preparation of toner particles] Ion-exchanged water: 200 parts Cyan colorant-containing amorphous polyester resin particle dispersion (C1): 145 parts Styrene acrylic resin particle dispersion (S1): 30 parts Release agent particle dispersion (W1): 10 parts The above materials were placed in a round stainless steel flask, and 0.1N (0.1mol / L) nitric acid was added to adjust the pH to 3.5, after which an aqueous magnesium chloride solution in which 6 parts of magnesium chloride were dissolved in 30 parts of ion-exchanged water was added. The materials were dispersed at 30°C using a homogenizer (IKA Ultra Turrax T50), and then heated to 45°C in a heating oil bath and maintained until the volume average particle size reached 4.5μm.

[0182] Next, 30 parts of the amorphous polyester resin particle dispersion (A1) and 15 parts of the crystalline polyester resin particle dispersion (B1) were added and held for 30 minutes. These two dispersions were added at 30 minute intervals a total of four times. Next, 40 parts of the amorphous polyester resin particle dispersion (A1) was added, and the pH was adjusted to 9.0 with a 1N aqueous sodium hydroxide solution. Next, while continuing stirring, the temperature was increased to 85°C at a rate of 0.05°C / min, and after being held at 85°C for 3 hours, it was cooled to 30°C at a rate of 15°C / min (first cooling). Next, it was heated to 85°C at a rate of 0.2°C / min (reheating), held for 30 minutes, and then cooled to 30°C at a rate of 0.5°C / min (second cooling). Next, the solid content was filtered off, washed with ion-exchanged water, and dried to obtain cyan toner particles (C1) having a volume average particle size of 5.9 μm.

[0183] [External addition of additives] 100 parts of cyan toner particles (C1) and 1.5 parts of hydrophobic silica (RY50, manufactured by Nippon Aerosil Co., Ltd.) were mixed and mixed for 30 seconds at a rotation speed of 10,000 rpm using a sample mill. The mixture was sieved using a vibrating sieve with an opening of 45 μm to obtain toner (C1). The volume average particle diameter of toner (C1) was 5.9 μm.

[0184] [Creating the carrier] After 500 parts of spherical magnetite powder particles (volume average particle diameter 0.55 μm) were stirred with a Henschel mixer, 5 parts of a titanate-based coupling agent were added, and the mixture was heated to 100 ° C and stirred for 30 minutes. Next, 6.25 parts of phenol, 9.25 parts of 35% formalin, 500 parts of magnetite particles treated with a titanate-based coupling agent, 6.25 parts of 25% ammonia water, and 425 parts of water were added to a four-neck flask and stirred, and reacted at 85 ° C for 120 minutes while stirring. Next, the mixture was cooled to 25 ° C, 500 parts of water were added, and the supernatant liquid was removed and the precipitate was washed with water. The washed precipitate was heated and dried under reduced pressure to obtain a carrier (CA) with an average particle size of 35 μm.

[0185] [Mixing toner and carrier] Cyan toner (C1) and carrier (CA) were placed in a V blender in a ratio of toner (C1):carrier (CA)=5:95 (mass ratio) and stirred for 20 minutes to obtain a cyan developer (C1).

[0186] [Preparation of various developers] Magenta toner particles (M1), yellow toner particles (Y1) and black toner particles (K1) were obtained in the same manner as for the cyan toner particles (C1), except that the cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to a magenta colorant-containing amorphous polyester resin particle dispersion (M1), a yellow colorant-containing amorphous polyester resin particle dispersion (Y1) and a black colorant-containing amorphous polyester resin particle dispersion (K1). Then, a magenta developer (M1), a yellow developer (Y1), and a black developer (K1) were obtained in the same manner as the cyan developer (C1), except that the obtained toner particles were used instead of the cyan toner particles (C1).

[0187] The resulting set of developers of each color was used as the developer set of Example 1.

[0188] <Examples 2 and 4, Comparative Example 1> Cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to cyan colorant-containing amorphous polyester resin particle dispersion (C2, C4, C6), magenta colorant-containing amorphous polyester resin particle dispersion (M2, M4, M6), yellow colorant-containing amorphous polyester resin particle dispersion (Y2, Y4, Y6), and black colorant-containing amorphous polyester resin particle dispersion (K2, K4, K6), and a calcium chloride aqueous solution obtained by dissolving 3 parts of calcium chloride in 30 parts of ion-exchanged water was added together with the magnesium chloride aqueous solution. Except for this, cyan toner particles (C2, C4, C6), magenta toner particles (M2, M4, M6), yellow toner particles (Y2, Y4, Y6), and black toner particles (K2, K4, K6) were obtained in the same manner as for the cyan toner particles (C1). Then, cyan developers (C2, C4, C6), magenta developers (M2, M4, M6), yellow developers (Y2, Y4, Y6), and black developers (K2, K4, K6) were obtained in the same manner as for the cyan developer (C1), except that the obtained toner particles were used instead of the cyan toner particles (C1). The resulting developer sets of each color were designated as developer sets of Example 2, Comparative Example 1, and Example 4.

[0189] <Examples 3 and 5, Comparative Example 2> Cyan toner particles (C3, C5, C7), magenta toner particles (M3, M5, M7), yellow toner particles (Y3, Y5, Y7), and black toner particles (K3, K5, K7) were obtained in the same manner as for the cyan toner particles (C1), except that the cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to a cyan colorant-containing amorphous polyester resin particle dispersion (C3, C5, C7), a magenta colorant-containing amorphous polyester resin particle dispersion (M3, M5, M7), a yellow colorant-containing amorphous polyester resin particle dispersion (Y3, Y5, Y7), or a black colorant-containing amorphous polyester resin particle dispersion (K3, K5, K7). Then, cyan developers (C3, C5, C7), magenta developers (M3, M5, M7), yellow developers (Y3, Y5, Y7), and black developers (K3, K5, K7) were obtained in the same manner as for the cyan developer (C1), except that the obtained toner particles were used instead of the cyan toner particles (C1). The obtained developer sets of each color were designated as developer sets of Example 3, Comparative Example 2, and Example 5.

[0190] <Example 6> Cyan toner particles (C8) were obtained in the same manner as for the cyan toner particles (C1), except that an aqueous calcium chloride solution prepared by dissolving 2 parts of calcium chloride in 30 parts of ion-exchanged water was added together with the aqueous magnesium chloride solution. In addition, magenta toner particles (M8), yellow toner particles (Y8), and black toner particles (K8) were obtained in the same manner as for the cyan toner particles (C8), except that the cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to a magenta colorant-containing amorphous polyester resin particle dispersion (M1), a yellow colorant-containing amorphous polyester resin particle dispersion (Y1), and a black colorant-containing amorphous polyester resin particle dispersion (K1). Then, cyan developer (C8), magenta developer (M8), yellow developer (Y8), and black developer (K8) were obtained in the same manner as cyan developer (C1), except that the obtained toner particles were used instead of cyan toner particles (C1). The resulting set of developers of each color was used as the developer set of Example 6.

[0191] <Example 7> Cyan toner particles (C9) were obtained in the same manner as for the cyan toner particles (C1), except that an aqueous calcium chloride solution prepared by dissolving 4 parts of calcium chloride in 30 parts of ion-exchanged water was added together with the aqueous magnesium chloride solution. In addition, magenta toner particles (M9), yellow toner particles (Y9), and black toner particles (K9) were obtained in the same manner as for the cyan toner particles (C9), except that the cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to a magenta colorant-containing amorphous polyester resin particle dispersion (M1), a yellow colorant-containing amorphous polyester resin particle dispersion (Y1), and a black colorant-containing amorphous polyester resin particle dispersion (K1). Then, cyan developer (C9), magenta developer (M9), yellow developer (Y9), and black developer (K9) were obtained in the same manner as cyan developer (C1), except that the obtained toner particles were used instead of cyan toner particles (C1). The resulting set of developers of each color was used as the developer set of Example 7.

[0192] <Example 8> Cyan toner particles (C10) were obtained in the same manner as the cyan toner particles (C1), except that the crystalline polyester resin particle dispersion (B1) was changed to the crystalline polyester resin particle dispersion (B2). In addition, magenta toner particles (M10), yellow toner particles (Y10), and black toner particles (K10) were obtained in the same manner as the cyan toner particles (C10), except that the cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to the magenta colorant-containing amorphous polyester resin particle dispersion (M1), the yellow colorant-containing amorphous polyester resin particle dispersion (Y1), and the black colorant-containing amorphous polyester resin particle dispersion (K1). Then, cyan developer (C10), magenta developer (M10), yellow developer (Y10), and black developer (K10) were obtained in the same manner as cyan developer (C1), except that the obtained toner particles were used instead of cyan toner particles (C1). The resulting set of developers for each color was used as the developer set of Example 8.

[0193] <Example 9> Cyan toner particles (C11) were obtained in the same manner as for the cyan toner particles (C1), except that the release agent particle dispersion (W1) was changed to the release agent particle dispersion (W2). In addition, magenta toner particles (M11), yellow toner particles (Y11), and black toner particles (K11) were obtained in the same manner as for the cyan toner particles (C11), except that the cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to the magenta colorant-containing amorphous polyester resin particle dispersion (M1), the yellow colorant-containing amorphous polyester resin particle dispersion (Y1), and the black colorant-containing amorphous polyester resin particle dispersion (K1). Then, cyan developer (C11), magenta developer (M11), yellow developer (Y11), and black developer (K11) were obtained in the same manner as cyan developer (C1), except that the obtained toner particles were used instead of cyan toner particles (C1). The resulting set of developers for each color was used as the developer set of Example 9.

[0194] <Example 10> Cyan toner particles (C12) were obtained in the same manner as the cyan toner particles (C1), except that the amount of styrene acrylic resin particle dispersion (S1) was changed from 30 parts to 50 parts, and the amount of crystalline polyester resin particle dispersion (B1) added four times in total was changed from 15 parts to 20 parts. In addition, magenta toner particles (M12), yellow toner particles (Y12), and black toner particles (K12) were obtained in the same manner as the cyan toner particles (C12), except that the cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to the magenta colorant-containing amorphous polyester resin particle dispersion (M1), the yellow colorant-containing amorphous polyester resin particle dispersion (Y1), and the black colorant-containing amorphous polyester resin particle dispersion (K1). Then, cyan developer (C12), magenta developer (M12), yellow developer (Y12), and black developer (K12) were obtained in the same manner as cyan developer (C1), except that the obtained toner particles were used instead of cyan toner particles (C1). The resulting set of developers for each color was designated as the developer set of Example 10.

[0195] <Example 11> Cyan toner particles (C13) were obtained in the same manner as the cyan toner particles (C1), except that the amount of styrene acrylic resin particle dispersion (S1) was changed from 30 parts to 10 parts, the amount of release agent particle dispersion (W1) was changed from 10 parts to 5 parts, and the amount of crystalline polyester resin particle dispersion (B1) added a total of four times was changed from 15 parts to 2.5 parts. In addition, magenta toner particles (M1), yellow toner particles (Y1), and black toner particles (K13) were obtained in the same manner as the cyan toner particles (C13), except that the cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to the magenta colorant-containing amorphous polyester resin particle dispersion (M1), the yellow colorant-containing amorphous polyester resin particle dispersion (Y1), and the black colorant-containing amorphous polyester resin particle dispersion (K1). Then, cyan developer (C13), magenta developer (M13), yellow developer (Y13), and black developer (K13) were obtained in the same manner as cyan developer (C1), except that the obtained toner particles were used instead of cyan toner particles (C1). The resulting set of developers for each color was used as the developer set of Example 11.

[0196] <Example 12> Cyan toner particles (C14) were obtained in the same manner as the cyan toner particles (C1), except that the amount of styrene acrylic resin particle dispersion (S1) was changed from 30 parts to 50 parts, the amount of release agent particle dispersion (W1) was changed from 10 parts to 40 parts, and the amount of crystalline polyester resin particle dispersion (B1) added a total of four times was changed from 15 parts to 20 parts. In addition, magenta toner particles (M1), yellow toner particles (Y1), and black toner particles (K14) were obtained in the same manner as the cyan toner particles (C14), except that the cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to the magenta colorant-containing amorphous polyester resin particle dispersion (M1), the yellow colorant-containing amorphous polyester resin particle dispersion (Y1), and the black colorant-containing amorphous polyester resin particle dispersion (K1). Then, cyan developer (C14), magenta developer (M14), yellow developer (Y14), and black developer (K14) were obtained in the same manner as cyan developer (C1), except that the obtained toner particles were used instead of cyan toner particles (C1). The resulting set of developers for each color was used as the developer set of Example 12.

[0197] <Example 13> Cyan toner particles (C15) were obtained in the same manner as the cyan toner particles (C1), except that the amount of styrene acrylic resin particle dispersion (S1) was changed from 30 parts to 10 parts, the amount of release agent particle dispersion (W1) was changed from 10 parts to 5 parts, and the amount of crystalline polyester resin particle dispersion (B1) added a total of four times was changed from 15 parts to 0 parts. In addition, magenta toner particles (M1), yellow toner particles (Y1), and black toner particles (K15) were obtained in the same manner as the cyan toner particles (C15), except that the cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to the magenta colorant-containing amorphous polyester resin particle dispersion (M1), the yellow colorant-containing amorphous polyester resin particle dispersion (Y1), and the black colorant-containing amorphous polyester resin particle dispersion (K1). Then, cyan developer (C15), magenta developer (M15), yellow developer (Y15), and black developer (K15) were obtained in the same manner as cyan developer (C1), except that the obtained toner particles were used instead of cyan toner particles (C1). The resulting set of developers for each color was used as the developer set of Example 13.

[0198] <Example 14> Cyan toner particles (C16) were obtained in the same manner as cyan toner particles (C1), except that the amorphous polyester resin particle dispersion (A1) was changed to a hybrid resin (amorphous polyester resin segment and a styrene acrylic resin segment having a particle dispersion (SPE1). In addition, magenta toner particles (M16), yellow toner particles (Y16), and black toner particles (K16) were obtained in the same manner as cyan toner particles (C16), except that the cyan colorant-containing amorphous polyester resin particle dispersion (C1) was changed to a magenta colorant-containing amorphous polyester resin particle dispersion (M1), a yellow colorant-containing amorphous polyester resin particle dispersion (Y1), and a black colorant-containing amorphous polyester resin particle dispersion (K1). Then, cyan developer (C16), magenta developer (M16), yellow developer (Y16), and black developer (K16) were obtained in the same manner as cyan developer (C1), except that the obtained toner particles were used instead of cyan toner particles (C1). The resulting set of developers for each color was used as the developer set of Example 14.

[0199] [Measurement of net intensity of each element] Of the developer sets of each example, the net intensity of the following elements was measured for the toner particles in the cyan developer according to the method described above. The results are shown in Table 1. Note that the "net intensity of each element" of the toner particles in the developers of the other colors was almost the same as the "net intensity of each element" of the toner particles in the cyan developer. Net strength of sulfur N S (In the table, “S(N S ") ·Net strength of alkali metals and alkaline earth metals N A (In the table, "ALKALI(N A ) Net strength of NaN N (In the table, “Na(N N )" Net strength of Mg N M (In the table, “Mg(N M )" Net strength of CaN Ca (In the table, “Ca(N Ca )" ·Net strength N of the sum of alkali metals and alkaline earth metals other than Na, Mg and Ca A-NM ((In the table, “ALKALI-(Na+Mg+Ca)(N A-NMC )" · Chlorine Net Strength N Cl (In the table, “Cl(N Cl )" Area ratio of colorant dispersion region in toner particle cross section (%)

[0200] [Color Gamut Evaluation] The developer set of each example was placed in the developing device of a modified image forming apparatus ApeosPortIV C5575 (manufactured by Fuji Xerox Co., Ltd.). Using this modified apparatus, the amount of toner for developing each monochrome 100% image on OK topcoat paper was 4.0 g / m 2 The image density (L*) and chroma (C*=(a*2+b*2)) were measured. The image density (L*) and chroma (C*=(a*2+b*2)) were then ... 0.5 The measurement was performed using an X-Rite 939 (aperture 4 mm), and the image plane was randomly measured 10 times and averaged. The evaluation was based on the following criteria.

[0201] (Cyan / Magenta (C / M) secondary color image density) G5: L* is less than 18 G4: L* is 18 or more and less than 19 G3: L* is between 19 and 20 G2: L* is 20 or more and less than 21 G1: L* is 21 or more The smaller the cyan / magenta (C / M) secondary color image density (L*), the higher the density, and G3 to G5 are within the allowable range.

[0202] (Cyan / Magenta (C / M) secondary color image saturation) G5: 56 or more C*s G4: C* is 54 or more but less than 56 G3: C* is 52 or more but less than 54 G2: C* is between 50 and 52 G1: C* less than 48 The higher the cyan / magenta (C / M) secondary color image saturation (C*), the higher the saturation, with G3 to G5 being the allowable range.

[0203] (Cyan / Yellow (C / Y) secondary color image density) G5: L* is less than 48 G4: L* is 48 or more and less than 49 G3: L* is between 49 and 50 G2: L* is 50 or more and less than 51 G1: L* is 51 or more The smaller the cyan / yellow (C / Y) secondary color image density (L*), the higher the density, and G3 to G5 are within the allowable range.

[0204] (Cyan / Yellow (C / Y) secondary color image saturation) G5: 76 or more C* G4: C* is 74 or more but less than 76 G3: C* is 72 or more but less than 74 G2: C* is between 70 and 72 G1: C* less than 70 The higher the cyan / yellow (C / Y) secondary color image saturation (C*), the higher the saturation, with G3 to G5 being the allowable range.

[0205] (Magenta / Yellow (M / Y) secondary color image density) G5: L* is less than 47 G4: L* is 47 or more and less than 48 G3: L* is 48 or more and less than 49 G2: L* is between 49 and 50 G1: L* is 50 or more The smaller the magenta / yellow (M / Y) secondary color image density (L*), the higher the density, and G3 to G5 are within the allowable range.

[0206] (Magenta / Yellow (M / Y) secondary color image saturation) G5: C* 90 or higher G4: C* is 88 or higher but less than 90 G3: C* is 86 or higher but less than 88 G2: C* is 84 or more but less than 86 G1: C* below 82 The higher the magenta / yellow (M / Y) secondary color image saturation (C*), the higher the saturation, with G3 to G5 being the allowable range.

[0207] [Transfer efficiency evaluation] The developer set of each example was placed in a developing device of a modified image forming apparatus ApeosPortIV C5575 (manufactured by Fuji Xerox Co., Ltd.) After leaving the modified apparatus for one day in a high temperature and high humidity environment (30°C, 85% RH), 10,000 images with an image density of 1% were output. After that, a 3cm x 4cm solid batch of cyan was developed and transferred, and the transferred toner image on the intermediate transfer belt was sampled using the adhesiveness of the adhesive tape surface, and its mass (W1) was measured. Next, the same toner image was transferred to the surface of paper, and the mass (W2) of the transferred image was measured. From these results, the transfer efficiency was calculated using the following formula. Transfer efficiency (%) = (W2 / W1) x 100 A(〇): 90% or more B(△): 80% or more but less than 90% C(×): Less than 80%

[0208] [Table 1-1]

[0209] [Table 1-2]

[0210] [Table 1-3]

[0211] From the above results, it is understood that the color gamut of the secondary color image is improved in this embodiment compared to this comparative example, and the transfer efficiency is also good. [Explanation of symbols]

[0212] 1Y, 1M, 1C, 1K Photoconductor (an example of an image carrier) 2Y, 2M, 2C, 2K Charging roll (an example of a charging means) 3 Exposure device (an example of an electrostatic image forming means) 3Y, 3M, 3C, 3K laser beam 4Y, 4M, 4C, 4K developing device (an example of developing means) 5Y, 5M, 5C, 5K Primary transfer roll (an example of a primary transfer means) 6Y, 6M, 6C, 6K Photoconductor cleaning device (an example of a cleaning means) 8Y, 8M, 8C, 8K toner cartridges 10Y, 10M, 10C, 10K Image forming units 20 Intermediate transfer belt (an example of an intermediate transfer body) 22 Driving Roll 24 Support roll 26 Secondary transfer roll (an example of a secondary transfer means) 28 Fixing device (an example of a fixing means) 30 Intermediate transfer body cleaning device P Recording paper (an example of a recording medium) 107 Photoconductor (an example of an image carrier) 108 Charging roll (an example of charging means) 109 Exposure device (an example of electrostatic image forming means) 111 Developing device (an example of developing means) 112 Transfer device (an example of a transfer means) 113 Photoconductor cleaning device (an example of a cleaning means) 115 Fixing device (an example of fixing means) 116 Mounting Rail 117 Cabinet 118 Exposure Aperture 200 Process Cartridge 300 Recording paper (an example of a recording medium)

Claims

1. The binder resin and the colorant are contained, and the net strength N of sulfur is measured by fluorescent X-ray analysis. Ｓ and the total net strength N of alkali metals and alkaline earth metals Ａ And, 1.0<N Ｓ / N Ａ <22.0, and the net strength N S of the sulfur is 3.0 kcps or more and 6.0 kcps or less.

2. The net strength of the sulfur N Ｓ and the total net strength N of the alkali metal and alkaline earth metal Ａ And, 1.0<N Ｓ / N Ａ 2. The toner for developing electrostatic images according to claim 1, which satisfies the relationship:

3. The net strength of the sulfur N Ｓ 3. The toner for developing electrostatic images according to claim 1, wherein the viscosity is 3.5 kcps or more and 5.5 kcps or less.

4. The total net strength N of the alkali metal and alkaline earth metal Ａ 4. The toner for developing electrostatic images according to claim 1, wherein the viscosity is 0.2 kcps or more and 4.2 kcps or less.

5. The total net strength N of the alkali metal and alkaline earth metal Ａ 5. The toner for developing electrostatic images according to claim 4, wherein the viscosity is 2.0 kcps or more and 4.0 kcps or less.

6. In the toner particles, the net intensity N of chlorine measured by fluorescent X-ray analysis Ｃｌ is 0.10 kcps or more and 1.30 kcps or less, and the net strength N Ｓ and the net strength of chlorine N Ｃｌ and 3<N Ｓ / N Ｃｌ The toner for developing electrostatic images according to any one of claims 1 to 5, which satisfies the relationship: <40.

7. 7. The toner for developing electrostatic images according to claim 1, wherein the alkali metal and alkaline earth metal include at least one selected from the group consisting of Na, Mg, and Ca.

8. In the toner particles, the net strength N Ｓ and the net strength of Mg N Ｍ And, 15.0<N Ｓ / N Ｍ 8. The toner for developing electrostatic images according to claim 1, wherein the toner satisfies the relationship:

9. 9. The toner for developing an electrostatic image according to claim 1, wherein the toner particles contain, as the binder resin, an amorphous polyester resin and a crystalline polyester resin.

10. 10. The toner for developing electrostatic images according to claim 9, wherein the crystalline polyester resin is a polymer of a linear α,ω-aliphatic dicarboxylic acid and a linear α,ω-aliphatic diol.

11. 11. The toner for developing electrostatic images according to claim 10, wherein the polymer of an α,ω-straight-chain aliphatic dicarboxylic acid and an α,ω-straight-chain aliphatic diol is a polymer of 1,10-decanedicarboxylic acid and 1,6-hexanediol.

12. The toner for developing an electrostatic image according to any one of claims 1 to 11, wherein the toner particles contain a releasing agent.

13. 13. The toner for developing electrostatic images according to claim 12, wherein the release agent is an ester wax.

14. The toner for developing electrostatic images according to any one of claims 1 to 13, wherein, when a cross section of the toner particle is observed, an area ratio of a dispersion region of the colorant in the cross section of the toner particle is 60% or more and 95% or less.

15. The binder resin and the colorant are contained, and the net strength N of sulfur is measured by fluorescent X-ray analysis. Ｓ and the total net strength N of alkali metals and alkaline earth metals Ａ The difference between Ｓ -N Ａ <5.0, and the net strength N S of the sulfur is 3.0 kcps or more and 6.0 kcps or less.

16. 16. An electrostatic image developer comprising the toner for developing electrostatic images according to claim 1.

17. The toner for developing an electrostatic image according to any one of claims 1 to 15 is contained therein, A toner cartridge that is detachably attached to an image forming apparatus.

18. a developing unit that contains the electrostatic image developer according to claim 16 and develops an electrostatic image formed on a surface of an image carrier into a toner image by using the electrostatic image developer, A process cartridge that is detachably attached to an image forming apparatus.

19. An image carrier; a charging means for charging the surface of the image carrier; an electrostatic image forming means for forming an electrostatic image on the charged surface of the image carrier; a developing unit that contains the electrostatic image developer according to claim 16 and develops the electrostatic image formed on the surface of the image carrier into a toner image by the electrostatic image developer; a transfer means for transferring the toner image formed on the surface of the image carrier to a surface of a recording medium; a fixing means for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising:

20. a charging step of charging the surface of the image carrier; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier; a developing step of developing the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer according to claim 16; a transfer step of transferring the toner image formed on the surface of the image carrier onto a surface of a recording medium; a fixing step of fixing the toner image transferred onto the surface of the recording medium; The image forming method according to claim 1,

Images