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

Abstract

To provide an electrostatic image developing toner which is superior in terms of both fixability and thermal agglomeration resistance.SOLUTION: An electrostatic image developing toner is provided, comprising toner particles containing a binder resin comprising 90 mass% or more of an amorphous resin. On a differential molecular weight distribution curve based on gel permeation chromatography of tetrahydrofuran solubles, the electrostatic image developing toner has a maximum peak Ma in a molecular weight range of 2500 to 8000, inclusive, a minimum value Mm in a molecular weight range of 8000 to 280,000, non-inclusive, and a maximum peak Mb in a molecular weight range of 280,000 to 900,000, inclusive. An area ratio A / B is in a range of 5.5 to 10, inclusive, where A represents area of the differential molecular weight distribution curve with a molecular weight of 100 or greater and less than the minimum value Mm and B represents area of the differential molecular weight distribution curve with the minimum value Mm or grater and a molecular weight of 10,000,000 or less.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 a variety of 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 using a developer containing toner. This toner image is then transferred to a recording medium, and the toner image is then fixed to the recording medium. Through these steps, the image information is visualized as an image.

[0003] For example, Patent Document 1 describes a magnetic toner for developing electrostatic images, which contains at least a binder resin and a magnetic substance, in which the THF-insoluble content of the binder resin is less than 10% by weight based on the binder resin, and the weight-average molecular weight / number-average molecular weight (Mw / Mn) of the THF-soluble content of the binder resin in GPC (gel permeation chromatography) is ≥ 8, and there is one molecular weight peak MA between 15,000 and 40,000, one molecular weight peak MB between 380,000 and 1,000,000, and one molecular weight peak β between 40,000 and 1,000,000. The magnetic toner for developing electrostatic images is disclosed, characterized in that it has a molecular weight minimum value Md between 400 and 380,000, MB / MA=10-70, and SA:SB:Sd=1:0.2-0.5:0.2-0.5, where SA is the area of ​​the differential molecular weight distribution curve from molecular weight 400 to Md, SB is the area of ​​the differential molecular weight distribution curve from molecular weight Md to 5 million, and Sd is the area enclosed by the line connecting the apex of the molecular weight peak MA and the apex of the molecular weight peak MB and the differential molecular weight distribution curve.

[0004] Patent Document 2 states that "in a toner containing at least a binder resin, a colorant, and a wax, the molecular weight of the THF-soluble component of the toner measured by GPC is 5×10 in the integral molecular weight distribution. 5The proportion of the above is 1% by weight or less, and the integral molecular weight distribution is 3×10 3 The ratio of the following is 30% by weight or less, and the ratio of the integral molecular weight distribution is 5 × 10 3 The following ratio {W(5×10 3 )} and 1 × 10 in the integral molecular weight distribution 5 The ratio of W(1×10 5 )} and the ratio {W(5×10 3 ) / W(1×10 5 )} is 15 to 50." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 04-274253 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-201887 Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional toners for developing electrostatic images, the heat resistance to aggregation tends to decrease when the fixability is improved. Therefore, an object of the present invention is to provide a toner for developing electrostatic images having toner particles containing a binder resin, which has excellent both fixability and heat resistance to aggregation, compared to toners having an area ratio A / B described below of less than 5.5 or more than 10, or a ratio (Ha / Hb) described below of less than 2.7 or more than 6.0. [Means for solving the problem]

[0007] The means for solving the above problems include the following aspects.

[0008] <1> The toner particles contain a binder resin containing an amorphous resin in an amount of 90% by mass or more, In the differential molecular weight distribution curve of the tetrahydrofuran soluble fraction obtained by gel permeation chromatography, The maximum peak Ma is in the molecular weight range of 2500 to 8000. A minimum value Mm in the range of molecular weight greater than 8000 and less than 280,000, and It has a maximum peak Mb in the molecular weight range of 280,000 or more and 900,000 or less, When the area of ​​the differential molecular weight distribution curve for a molecular weight of 100 or more and less than the minimum value Mm is defined as A, and the area of ​​the differential molecular weight distribution curve for a molecular weight of 10,000,000 or more and less than the minimum value Mm is defined as B, A toner for developing electrostatic images, wherein the area ratio A / B of the two is 5.5 or more and 10 or less. <2> The toner particles contain a binder resin containing an amorphous resin in an amount of 90% by mass or more, In the differential molecular weight distribution curve of the tetrahydrofuran soluble fraction obtained by gel permeation chromatography, The maximum peak Ma is in the molecular weight range of 2500 to 8000. A minimum value Mm in the range of molecular weight greater than 8000 and less than 280,000, and It has a maximum peak Mb in the molecular weight range of 280,000 or more and 900,000 or less, The half width of the maximum peak Ma is 12,000 or more and 20,000 or less, The half width of the maximum peak Mb is 320,000 or more and 500,000 or less, and The toner for developing electrostatic images has a ratio (Ha / Hb) of the height Ha of the maximum peak Ma to the height Hb of the maximum peak Mb of 2.7 or more and 6.0 or less. <3> the relationship (Mb-Mm) / (Mm-Ma) between the maximum peak Ma, the minimum value Mm, and the maximum peak Mb is 1.0 or more and 2.4 or less; <1> or <2> 2. The toner for developing electrostatic images according to claim 1. <4> The toner particles further contain a release agent. <1> ~ <3> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <5> The release agent contains an ester wax. <4> 2. The toner for developing electrostatic images according to claim 1. <6> The content of the release agent is 0.5% by mass or more and 4% by mass or less with respect to the toner particles. <4> or <5> 2. The toner for developing electrostatic images according to claim 1. <7> The melting temperature of the release agent is 57°C or higher and 68°C or lower. <4> ~ <6> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <8> the difference (Tm-Tg) between the melting temperature Tm of the release agent and the glass transition temperature Tg of the amorphous resin is 0°C or more and 10°C or less; <4> ~ <7> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <9> the toner particles have an average circularity of 0.915 or more and 0.950 or less; <1> ~ <8> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <10> the toner particles have a small diameter side number particle size distribution index (lower GSDp) of 1.33 or less; <1> ~ <9> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <11> The toluene-insoluble matter is 3% by mass or more and 8% by mass or less based on the toner particles. <1> ~ <10> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <12> The amorphous resin includes an amorphous polyester resin. <1> ~ <11> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <13> The aforementioned <1> ~ <12> 10. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 9. <14> The aforementioned <1> ~ <12> 10. A toner cartridge containing the toner for developing electrostatic images according to any one of claims 1 to 9, which is detachably mounted on an image forming apparatus. <15> The aforementioned <13> and a developing means for developing an electrostatic image formed on the surface of an image carrier using the electrostatic image developer into a toner image, the process cartridge being detachably mountable to an image forming apparatus. <16> 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; The aforementioned <13> 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 the 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: [Effects of the Invention]

[0009] <1> According to the invention, there is provided a toner for developing electrostatic images having toner particles containing a binder resin, which has excellent fixing properties and heat-resistant aggregation properties compared to toners having an area ratio A / B of less than 5.5 or more than 10.

[0010] <2> According to the invention, there is provided a toner for developing electrostatic images having toner particles containing a binder resin, which has excellent fixing properties and heat-resistant aggregation properties compared to toners having the ratio (Ha / Hb) of less than 2.7 or more than 6.0.

[0011] <3> According to the invention, a toner for developing electrostatic images is provided which is excellent in both fixing property and heat-resistant aggregation property compared to when the relationship (Mb-Mm) / (Mm-Ma) is less than 1.0 or exceeds 2.4.

[0012] <4> According to the invention, there is provided a toner for developing electrostatic images which is excellent in both fixability and heat-resistant cohesion properties compared to toner particles which do not contain a release agent.

[0013] <5> According to the invention, there is provided a toner for developing electrostatic images which is excellent in both fixability and heat-resistant cohesion compared to when the release agent is paraffin wax.

[0014] <6> According to the present invention, a toner for developing electrostatic images is provided which is excellent in both fixing property and heat-resistant aggregation property compared to when the content of the release agent is less than 0.5% by mass or more than 4% by mass relative to the toner particles.

[0015] <7> According to the invention, a toner for developing electrostatic images is provided which is excellent in both fixability and heat-resistant cohesion, compared to when the melting temperature of the release agent is lower than 57°C or higher than 68°C.

[0016] <8> According to the invention, a toner for developing electrostatic images is provided which is excellent in both fixability and heat-resistant aggregation properties compared to a toner in which the difference (Tm-Tg) between the melting temperature Tm of the release agent and the glass transition temperature Tg of the amorphous resin exceeds 10°C.

[0017] <9> According to the invention, there is provided a toner for developing electrostatic images which is excellent in both fixability and heat-resistant cohesion properties compared to toner particles having an average circularity of less than 0.915 or more than 0.950.

[0018] <10> According to the invention, a toner for developing electrostatic images is provided which is excellent in both fixability and heat-resistant cohesion properties compared to toner particles having a smaller diameter volume particle size distribution index (lower GSDv) of more than 1.33.

[0019] <11> According to the invention, a toner for developing electrostatic images is provided which is excellent in both fixability and heat-resistant cohesion properties compared to when the toluene-insoluble content is less than 3% by mass or more than 8% by mass of the toner particles.

[0020] <12> According to the invention, there is provided a toner for developing electrostatic images which is excellent in both fixability and heat-resistant cohesion compared to when the amorphous resin is a styrene-acrylic resin.

[0021] <13> , <14> , <15> or <16> According to the invention, there is provided an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, or an image forming method, which has excellent fixing properties and heat-resistant aggregation properties compared to when an electrostatic image developing toner having toner particles containing a binder resin is used, in which the area ratio A / B is less than 5.5 or more than 10, or the ratio (Ha / Hb) is less than 2.7 or more than 6.0. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram illustrating an example of a process cartridge that is detachably mounted to an image forming apparatus according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] The following describes an embodiment of the present invention, which is an example. These descriptions and examples are intended to illustrate the present invention, but are not intended to limit the present invention.

[0024] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the present specification, the upper or lower limit of one numerical range may be replaced by the upper or lower limit of another numerical range. In addition, in the numerical ranges described in this disclosure, the upper or lower limit of the numerical range may be replaced by the values ​​shown in the examples.

[0025] In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0026] When embodiments are described in this specification with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each drawing are conceptual, and the relative size relationships between the components are not limited to these.

[0027] In this specification, each component may contain multiple corresponding substances. When referring to the amount of each component in a composition in this 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.

[0028] In this 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.

[0029] 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."

[0030] <Toner for developing electrostatic images> The toner according to the first embodiment has toner particles containing a binder resin containing 90% by mass or more of an amorphous resin, and in a differential molecular weight distribution curve of a tetrahydrofuran soluble portion measured by gel permeation chromatography, the differential molecular weight distribution curve has a maximum peak Ma in a molecular weight range of 2,500 or more and 8,000 or less, a minimum value Mm in a molecular weight range of more than 8,000 and less than 280,000, and a maximum peak Mb in a molecular weight range of 280,000 or more and 900,000 or less, and when the area of ​​the differential molecular weight distribution curve from a molecular weight of 100 or more and less than the minimum value Mm is A and the area of ​​the differential molecular weight distribution curve from a molecular weight of 10,000,000 or more and the minimum value Mm is B, the area ratio A / B of the two is 5.5 or more and 10 or less.

[0031] The toner according to the second embodiment has toner particles containing a binder resin containing an amorphous resin at 90% by mass or more, and in a differential molecular weight distribution curve of a tetrahydrofuran soluble portion by gel permeation chromatography, the toner has a maximum peak Ma in a molecular weight range of 2500 or more and 8000 or less, a minimum value Mm in a molecular weight range of more than 8000 and less than 280,000, and a maximum peak Mb in a molecular weight range of 280,000 or more and 900,000 or less, the half width of the maximum peak Ma is 12,000 or more and 20,000 or less, the half width of the maximum peak Mb is 320,000 or more and 500,000 or less, and the ratio (Ha / Hb) of the height Ha of the maximum peak Ma to the height Hb of the maximum peak Mb is 2.7 or more and 6.0 or less.

[0032] On the other hand, the toners according to the first and second embodiments are excellent in both fixability and heat-resistant aggregation due to the above-described configuration. The reason for this is presumed to be as follows.

[0033] It is known that conventional toners use toner particles containing a binder resin containing, for example, more than 20% by mass of a crystalline resin relative to the total resin content, in order to improve fixability. However, when the crystalline resin is contained within the above range, while fixability (particularly low-temperature fixability at 160°C or less) is improved, the toner particles tend to aggregate when stored for a long period of time (e.g., 20 hours) in a high-temperature, high-humidity environment (e.g., 55°C, 50% RH), i.e., heat-resistant aggregation tends to decrease.

[0034] The toner according to the first embodiment contains a binder resin containing 90% by mass or more of an amorphous resin. The binder resin has at least one maximum peak in each of the molecular weight ranges of 2,500 to 8,000 and 280,000 to 900,000. In other words, the binder resin contains a relatively low molecular weight resin and a high molecular weight resin. Furthermore, in the toner according to the first embodiment, the area ratio A / B of the differential molecular weight distribution curve is 5.5 or more and 10 or less. In other words, when the minimum value Mm is used as the dividing line, the proportion of the relatively low molecular weight resin is moderately higher than the proportion of the relatively high molecular weight resin. It is believed that the fixability is achieved by including the relatively low molecular weight resin in the above proportion. It is also believed that the heat-resistant aggregation property is achieved by including the relatively high molecular weight resin in the above range.

[0035] The toner according to the second embodiment, like the toner according to the first embodiment, has a binder resin containing 90% by mass or more of an amorphous resin, and the binder resin contains the relatively low molecular weight resin and the high molecular weight resin. Furthermore, in the toner according to the second embodiment, the half-width of the maximum peak Ma is 12,000 or more and 20,000 or less, the half-width of the maximum peak Mb is 320,000 or more and 500,000 or less, and the ratio (Ha / Hb) of the height Ha of the maximum peak Ma to the height Hb of the maximum peak Mb is 2.7 or more and 6.0 or less. In other words, the proportion of the relatively low molecular weight resin having the maximum peak Ma is appropriately higher than the proportion of the relatively high molecular weight resin having the maximum peak Mb. Thus, it is believed that fixability is achieved by including the relatively low molecular weight resin in the above proportion. Furthermore, it is believed that heat-resistant aggregation is achieved by including the relatively high molecular weight resin in the above range.

[0036] In particular, the toner according to the first embodiment and the toner according to the second embodiment contain an appropriate amount of the relatively low molecular weight resin component, and therefore have excellent fixing properties at low temperatures (for example, 160°C or lower) even when the crystalline resin accounts for less than 20% by mass of the total resin.

[0037] Hereinafter, the toner that corresponds to both the toner according to the first embodiment and the toner according to the second embodiment will also be referred to as "the toner according to this embodiment."

[0038] The toner according to the exemplary embodiment includes toner particles, and may include an external additive that is externally added to the toner particles.

[0039] -Properties of toner- (Molecular weight curve, weight average molecular weight) The toner according to the present exemplary embodiment has a differential molecular weight distribution curve measured by gel permeation chromatography of a tetrahydrofuran soluble content, which has a molecular weight distribution curve of: The maximum peak Ma is in the molecular weight range of 2500 to 8000. A minimum value Mm in the range of molecular weight greater than 8000 and less than 280,000, and It has a maximum peak Mb in the molecular weight range of 280,000 to 900,000.

[0040] The maximum peak Ma refers to the maximum value of the peaks observed in the molecular weight range of 2500 to 8000 in the differential molecular weight distribution curve. For example, when multiple peaks are observed in the molecular weight range of 2500 to 8000, the maximum peak Ma refers to the maximum value of the peak with the highest differential distribution value. The maximum peak Mb refers to the maximum value of the peak observed in the molecular weight range of 280,000 to 900,000 in the differential molecular weight distribution curve. For example, when multiple peaks are observed in the molecular weight range of 280,000 to 900,000, the maximum peak Mb refers to the maximum value of the peak with the highest differential distribution value. The minimum value Mm refers to the smallest differential distribution value observed in the differential molecular weight distribution curve in the molecular weight range of more than 8000 and less than 280000. For example, when multiple minimum values ​​(i.e., peaks and valleys) are observed in the molecular weight range of more than 8000 and less than 280000, the minimum value Mm refers to the peak and valley where the differential distribution value is the smallest.

[0041] The maximum peak Ma in the molecular weight range of 2500 to 8000 and the maximum peak Mb in the molecular weight range of 280000 to 900000 are peaks derived from the binder resin, and preferably from the amorphous resin.

[0042] There are no particular limitations on the specific method for setting the maximum peak Ma, minimum value Mm, and maximum peak Mb within the above ranges. For example, one method includes using a binder resin containing an amorphous resin a1 having a weight-average molecular weight of 8,000 or more and 280,000 or less (more preferably, 10,000 or more and 25,000 or less) and an amorphous resin b1 having a weight-average molecular weight of 300,000 or more and 1,100,000 or less (more preferably, 350,000 or more and 900,000 or less).

[0043] The molecular weight curve and weight-average molecular weight were measured using a gel permeation chromatography (GPC) system (HLC-8420GCP, Tosoh Corporation) with a Tosoh column, TSKgel SuperHM-M (15 cm), and tetrahydrofuran (THF) as the solvent. From these measurement results, a molecular weight curve was created using a monodisperse polystyrene standard sample. The weight-average molecular weight was then calculated using the differential molecular weight distribution curve. The horizontal axis of the differential molecular weight distribution curve is the logarithmic function of molecular weight (LogM), and the vertical axis is the differential distribution value (dw / d(LogM)).

[0044] ·Area ratio A / B In the toner according to the first embodiment, when the area of ​​the differential molecular weight distribution curve for a molecular weight of 100 or more and less than the minimum value Mm is defined as A, and the area of ​​the differential molecular weight distribution curve for a molecular weight of 100 or more and less than the minimum value Mm is defined as B, the area ratio A / B between the two is 5.5 or more and 10 or less, and from the viewpoint of obtaining a toner that is excellent in both fixability and heat-resistant aggregation, it is preferably 6.0 or more and 9.0 or less, and more preferably 6.1 or more and 8.5 or less. In the toner according to the second embodiment, from the viewpoint of providing a toner having excellent fixing properties and heat-resistant aggregation properties, when the area of ​​the differential molecular weight distribution curve for a molecular weight of 100 or more and less than the minimum value Mm is defined as A and the area of ​​the differential molecular weight distribution curve for a molecular weight of 10,000,000 or more and less than the minimum value Mm is defined as B, the area ratio A / B of the two is preferably 5.5 or more and 10 or less, more preferably 6.0 or more and 9.0 or less, and even more preferably 6.1 or more and 8.5 or less.

[0045] There are no particular limitations on the specific method for setting the area ratio A / B within the above range, but an example of such a method is to adjust the compounding ratio of the aforementioned amorphous resin a1 having a weight average molecular weight of 8,000 or more and 28,000 or less (more preferably 10,000 or more and 25,000 or less) as the binder resin to the amorphous resin b1 having a weight average molecular weight of 300,000 or more and 1,100,000 or less (more preferably 350,000 or more and 900,000 or less).

[0046] Half width In order to provide a toner according to the first embodiment with superior fixing properties and heat-resistant aggregation properties, the half width of the maximum peak Ma is preferably 8,000 or more and 27,000 or less, more preferably 9,000 or more and 25,000 or less, even more preferably 12,000 or more and 20,000 or less, particularly preferably 13,000 or more and 19,000 or less, and most preferably 14,000 or more and 18,000 or less. The toner according to the second embodiment has a half-value width of the maximum peak Ma of 12,000 or more and 20,000 or less, and from the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant aggregation properties, it is more preferable that the half-value width is 13,000 or more and 19,000 or less, and even more preferable that the half-value width is 14,000 or more and 18,000 or less.

[0047] In order to provide a toner according to the first embodiment with excellent fixing properties and heat-resistant aggregation properties, the half-value width of the maximum peak Mb is preferably 200,000 or more and 800,000 or less, more preferably 250,000 or more and 700,000 or less, even more preferably 320,000 or more and 500,000 or less, particularly preferably 350,000 or more and 490,000 or less, and most preferably 370,000 or more and 470,000 or less. The toner according to the second embodiment has a half-value width of the maximum peak Mb of 320,000 or more and 500,000 or less, and from the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant aggregation properties, it is more preferable that the half-value width is 350,000 or more and 490,000 or less, and even more preferable that the half-value width is 370,000 or more and 470,000 or less.

[0048] There are no particular limitations on the specific method for setting each half width within the above range, and examples include a method of adjusting the amount of catalyst, the mixing ratio of monomers, the reaction rate, etc. when synthesizing the binder resin; a method of using a binder resin containing an amorphous resin a1 having a weight-average molecular weight of 8,000 or more and 28,000 or less (more preferably, 10,000 or more and 25,000 or less) and an amorphous resin b1 having a weight-average molecular weight of 300,000 or more and 1,100,000 or less (more preferably, 350,000 or more and 900,000 or less); and the like.

[0049] The half-width of the maximum peak Ma is determined as follows. First, starting from the minimum value Mm, a straight line B parallel to the baseline is drawn. Next, the linear distance from the point Ma0 where the maximum peak Ma and line B perpendicularly intersect to the maximum peak Ma is defined as the "height of the maximum peak Ma." The peak width (full width at half maximum) at half the height of the obtained maximum peak Ma (differential distribution value) is called the half width of the maximum peak Ma.

[0050] The half-width of the maximum peak Mb is determined as follows. First, starting from the minimum value Mm, a straight line B parallel to the baseline is drawn. Next, the linear distance from the point Mb0 where the maximum peak Ma and the line B intersect perpendicularly to the maximum peak Mb is defined as the "height of the maximum peak Mb." The peak width at half the height of the obtained maximum peak Mb (differential distribution value) (full width at half maximum) is called the half width of the maximum peak Mb.

[0051] ·Ratio (Ha / Hb) In order to provide a toner according to the first embodiment that is superior in both fixability and heat-resistance to aggregation, the ratio (Ha / Hb) of the height Ha of the maximum peak Ma to the height Hb of the maximum peak Mb is preferably 2.3 or more and 7.0 or less, more preferably 2.5 or more and 6.5 or less, even more preferably 2.7 or more and 6.0 or less, particularly preferably 2.8 or more and 5.9 or less, and most preferably 2.9 or more and 5.8 or less. In the toner according to the second embodiment, the ratio (Ha / Hb) of the height Ha of the maximum peak Ma to the height Hb of the maximum peak Mb is 2.7 or more and 6.0 or less, and from the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant aggregation properties, it is particularly preferable that the ratio is 2.8 or more and 5.9 or less, and most preferably 2.9 or more and 5.8 or less.

[0052] (Mb-Mm) / (Mm-Ma) In order to provide the toner according to this embodiment with superior fixing properties and heat-resistant aggregation properties, the relationship (Mb-Mm) / (Mm-Ma) between the maximum peak Ma, the minimum value Mm, and the maximum peak Mb is preferably 1.0 or more and 2.4 or less, more preferably 1.2 or more and 2.35 or less, and even more preferably 1.3 or more and 2.3 or less.

[0053] There are no particular limitations on the specific methods for setting the ratios (Ha / Hb) and (Mb-Mm) / (Mm-Ma) within the above ranges, but an example of such a method is to adjust the compounding ratio of the aforementioned amorphous resin a1 having a weight-average molecular weight of 8,000 or more and 28,000 or less (more preferably 10,000 or more and 25,000 or less) as the binder resin to the amorphous resin b1 having a weight-average molecular weight of 300,000 or more and 1,100,000 or less (more preferably 350,000 or more and 900,000 or less). Examples include:

[0054] -Characteristics of toner particles- The toner particles may be toner particles of a single layer structure, or may be toner particles of a so-called core-shell structure composed of a core part (core particle) and a coating layer (shell layer) that coats the core part. 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.

[0055] From the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant aggregation properties, the toner particles preferably have a toluene-insoluble content of 3% by mass or more and 8% by mass or less, more preferably 3.5% by mass or more and 7.5% by mass or less, and even more preferably 4% by mass or more and 7% by mass or less, based on the toner particles.

[0056] The toluene insoluble matter is a value measured by the following method. Weigh 250 mg of sample directly into an Erlenmeyer flask and record the weight to the nearest 0.1 mg. Pour 20 ml of toluene into the Erlenmeyer flask, seal it, and stir with a stirrer for 4 hours to dissolve the sample. Transfer the dissolved solution to a separation tube. Pour another 20 ml of toluene into the empty Erlenmeyer flask to wash the inside, then add this liquid to the separation tube and seal it with the lid. Centrifuge the separation tube at -9°C, 12,000 rpm, and 20 minutes. After centrifugation, leave the separation tube at room temperature for approximately 2 hours to allow the solution to return to room temperature. Weigh the empty aluminum dish and record the weight to the nearest 0.1 mg. Pipette 5 ml of the supernatant solution from the separation tube and transfer it to an aluminum dish. Place the aluminum dish on a heated hot plate to evaporate the toluene. Dry the aluminum dish in a vacuum dryer (50°C, approximately 8 hours). After drying, weigh the aluminum dish (toluene solubles + aluminum dish weight) and record to the nearest 0.1 mg. Calculate the toluene insolubles using the following formula: Toluene insolubles % = {A - [(BC) × 8]} ÷ A × 100 A: Sample weight [g] B: Weight of toluene solubles + aluminum dish [g] C: Weight of aluminum plate only [g] 8:40÷5 (5ml in 40ml)

[0057] The toluene-insoluble content can be adjusted, for example, by adjusting the blending ratio of the amorphous resin a1 having a weight-average molecular weight of 8,000 or more and 28,000 or less (more preferably 10,000 or more and 25,000 or less) to the amorphous resin b1 having a weight-average molecular weight of 300,000 or more and 1,100,000 or less (more preferably 350,000 or more and 900,000 or less) in the binder resin, or by adjusting the amount of crosslinking agent.

[0058] The volume average particle size (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0059] In order to obtain a toner having excellent fixing properties and heat-resistant aggregation properties, the small-diameter number particle size distribution index (lower GSDp) of the toner particles is preferably 1.33 or less, more preferably 1.10 or more and 1.30 or less, and even more preferably 1.15 or more and 1.25 or less.

[0060] The large diameter volume particle size distribution index (upper GSDv) of the toner particles may be 1.30 or less, 1.05 or more and 1.25 or less, or 1.10 or more and 1.20 or less.

[0061] There are no particular limitations on the method for adjusting the lower GSDp and upper GSDv of the toner particles to the above ranges. For example, when the toner is produced by a kneading and pulverization method, adjustments can be made by removing fine powder and coarse powder in a classification process after pulverization.

[0062] The various average particle sizes and particle size distribution indices of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using an ISOTON-II (manufactured by Beckman Coulter). For the measurement, 0.5 mg to 50 mg of the sample to be measured 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 solution containing the suspended sample is dispersed in an ultrasonic disperser for 1 minute, and the particle size distribution of particles 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. A cumulative distribution of the volume is drawn from the smallest diameter side for the particle size range (channel) divided based on the measured particle size distribution, and the particle size at 16% of the cumulative total is defined as the volume particle size D16v, the particle size at 50% of the cumulative total as the volume average particle size D50v, and the particle size at 84% of the cumulative total as the volume particle size D84v. A cumulative distribution of the number is drawn from the smallest diameter side, and the particle size at 16% of the cumulative total is defined as the number particle size D16p, the particle size at 50% of the cumulative total as the number average particle size D50p, and the particle size at 84% of the cumulative total as the number particle size D84p. Using these, the larger diameter volume particle size distribution index (upper GSDv) is calculated as (D84v / D50v), and the smaller diameter number particle size distribution index (lower GSDp) is calculated as (D50p / D16p).

[0063] From the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant cohesion, the average circularity of the toner particles is preferably 0.915 or more and 0.950 or less, more preferably 0.920 or more and 0.945 or less, and even more preferably 0.925 or more and 0.940 or less.

[0064] The method for adjusting the average circularity of toner particles to the above range is not particularly limited. For example, when the toner is produced by a kneading and pulverizing method, the toner particles may be subjected to hot air treatment after classification to adjust the average circularity.

[0065] 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, this value is measured by the following method. The toner particles to be measured are sucked and collected, forming a flat flow, and a still image of the particles is captured by instantly emitting a strobe light, which is then analyzed using 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 external additives, 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 additives have been removed.

[0066] - Composition of toner particles - The toner particles contain, for example, a binder resin. The toner particles may contain a colorant, a release agent, and other additives as necessary, and preferably contain a release agent from the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant aggregation properties.

[0067] -Binder resin- The binder resin contains an amorphous resin in an amount of 90% by mass or more relative to the total binder resin, and from the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant aggregation properties, the binder resin preferably contains an amorphous resin in an amount of 95% by mass or more and 100% by mass or less, and more preferably contains an amorphous resin in an amount of 98% by mass or more and 100% by mass or less.

[0068] As described above, the maximum peak Ma in the molecular weight range of 2500 or more and 8000 or less and the maximum peak Mb in the molecular weight range of 280,000 or more and 900,000 or less, which are observed in the differential molecular weight distribution curve of the tetrahydrofuran soluble matter by gel permeation chromatography, are peaks derived from the binder resin, and preferably peaks derived from the amorphous resin, respectively.

[0069] Here, the term "amorphous resin" refers to a resin that, in thermal analysis measurement using differential scanning calorimetry (DSC), does not show a clear endothermic peak but only a stepwise endothermic change, is solid at room temperature, and becomes thermoplastic at a temperature equal to or higher than the glass transition temperature. On the other hand, a crystalline resin is one that shows 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 the endothermic peak when measured at a heating rate of 10°C / min is within 10°C, and an amorphous resin means a resin whose half-width exceeds 10°C or a resin in which no clear endothermic peak is observed.

[0070] The amorphous resin will be described. Examples of amorphous resins include known amorphous resins such as amorphous polyester resins, amorphous vinyl resins (e.g., styrene-acrylic resins), epoxy resins, polycarbonate resins, polyurethane resins, etc. Among these, amorphous polyester resins and amorphous vinyl resins (particularly styrene-acrylic resins) are preferred, and amorphous polyester resins are 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.

[0071] Amorphous polyester resin The amorphous polyester resin may be, for example, a condensation polymer of a polycarboxylic acid and a polyhydric alcohol. As the amorphous polyester resin, a commercially available product or a synthesized product may be used.

[0072] Examples of polycarboxylic 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, and sebacic acid), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. The polycarboxylic 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 alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acids may be used alone or in combination of two or more.

[0073] 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 trihydric or higher polyhydric alcohol having a crosslinked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. The polyhydric alcohols may be used alone or in combination of two or more.

[0074] Amorphous polyester resins can be obtained by known production methods. Specifically, for example, the polymerization temperature is set to 180°C or higher and 230°C or lower, and the reaction system is reduced in pressure as necessary, and the reaction is carried out while removing water and alcohol generated during condensation. If the raw material monomers are not soluble or compatible at the reaction temperature, a high-boiling solvent may be added as a solubilizer to dissolve them. In this case, the polycondensation reaction is carried out while distilling off the solubilizer. If a monomer with poor compatibility is present in the copolymerization reaction, it is recommended that the poorly compatible monomer be condensed in advance with the acid or alcohol to be polycondensed, and then polycondensed with the main component.

[0075] Examples of the amorphous polyester resin include unmodified amorphous polyester resins and modified amorphous polyester resins. Modified amorphous polyester resins include amorphous polyester resins containing bonding groups other than ester bonds, and amorphous polyester resins in which a resin component other than polyester is bonded by a covalent bond, an ionic bond, or the like. Examples of modified amorphous polyester resins include resins in which an amorphous polyester resin having a functional group such as an isocyanate group introduced into the terminal thereof is reacted with an active hydrogen compound to modify the terminal.

[0076] 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.

[0077] Styrene acrylic resin Styrene-acrylic resins are copolymers 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 resins include, for example, copolymers 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. Furthermore, the term "(meth)acrylic" includes both "acrylic" and "methacrylic."

[0078] Examples of styrene-based monomers include styrene, α-methylstyrene, metachlorostyrene, parachlorostyrene, parafluorostyrene, paramethoxystyrene, meta-tert-butoxystyrene, para-tert-butoxystyrene, paravinylbenzoic acid, paramethyl-α-methylstyrene, etc. One type of styrene-based monomer may be used alone, or two or more types may be used in combination.

[0079] 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. One (meth)acrylic monomer may be used alone, or two or more may be used in combination.

[0080] 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.

[0081] 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 functional (meth)acrylate compound.

[0082] The method for producing the styrene-acrylic resin is not particularly limited, and for example, solution polymerization, precipitation polymerization, suspension polymerization, bulk polymerization, or emulsion polymerization is applied. For the polymerization reaction, a known operation (for example, a batch system, a semi-continuous system, or a continuous system) is applied.

[0083] The proportion of the styrene acrylic resin in the total binder resin is preferably 0% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less.

[0084] Amorphous resins having an amorphous polyester resin segment and a styrene-acrylic resin segment (hereinafter also referred to as "hybrid amorphous resins") The hybrid amorphous resin is an amorphous resin in which an amorphous polyester resin segment and a styrene-acrylic resin segment are chemically bonded. Examples of hybrid amorphous resins include resins having a main chain made of polyester resin and a side chain made of styrene-acrylic resin chemically bonded to the main chain; resins having a main chain made of styrene-acrylic resin and a side chain made of polyester resin chemically bonded to the main chain; resins having a main chain made of polyester resin and styrene-acrylic resin chemically bonded to the main chain; and resins having a main chain made of polyester resin and styrene-acrylic resin chemically bonded to the main chain, and at least one side chain made of polyester resin chemically bonded to the main chain and a side chain made of styrene-acrylic resin chemically bonded to the main chain.

[0085] The amorphous polyester resin and styrene-acrylic resin in each segment are as described above, and therefore further explanation will be omitted.

[0086] The amorphous resin preferably contains at least one of an amorphous polyester resin and an amorphous resin having a polyester resin segment and a styrene-acrylic segment.

[0087] The total amount of the polyester resin segment and the styrene-acrylic resin segment in the entire hybrid amorphous resin is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 100% by mass.

[0088] 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.

[0089] 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 subjected to addition polymerization. (ii) After preparing a styrene-acrylic resin segment by addition polymerization of an addition-polymerizable monomer, polyhydric alcohol and 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.

[0090] 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.

[0091] The characteristics of the amorphous resin will be explained. From the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant aggregation properties, the glass transition temperature (Tg) of the amorphous resin is preferably 30°C or higher and 90°C or lower, more preferably 35°C or higher and 85°C or lower, and even more preferably 40°C or higher and 80°C or lower.

[0092] There are no particular limitations on the specific method for adjusting the glass transition temperature Tg of the amorphous resin to fall within the above range. Examples include a method of adjusting the reaction rate when synthesizing the amorphous resin, and a method of adjusting the amount of crosslinking agent.

[0093] 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 JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0094] For example, when two or more amorphous resins are contained, the glass transition temperature Tg of the amorphous resin is determined to be the minimum value among the multiple observed glass transition temperatures.

[0095] The softening temperature of the amorphous resin is preferably 50°C or higher and 200°C or lower, more preferably 55°C or higher and 180°C or lower, and even more preferably 60°C or higher and 165°C or lower.

[0096] The softening temperature can be determined as follows. Using a flow tester "CFT-500D" (Shimadzu Corporation), 1 g of sample is heated at a temperature increase rate of 6°C / min while a load of 1.96 MPa is applied by the plunger, and the sample is extruded from a nozzle 1 mm in diameter and 1 mm in length. The plunger depression distance of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening temperature.

[0097] The binder resin according to this embodiment may contain a crystalline resin in an amount of less than 10% by mass relative to the entire binder resin. 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 in terms of the mechanical strength and low-temperature fixability of the toner.

[0098] Crystalline polyester resin Examples of the crystalline polyester resin include a polycondensate of a polycarboxylic acid and a polyhydric alcohol. As the crystalline polyester resin, a commercially available product or a synthesized product may be used. The crystalline polyester resin is preferably a polycondensate using a straight-chain aliphatic polymerizable monomer rather than a polymerizable monomer having an aromatic ring, since it easily forms a crystalline structure.

[0099] Examples of polycarboxylic 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, and naphthalene-2,6-dicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acid may be a tricarboxylic or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the tricarboxylic acid include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). As the polycarboxylic 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 polycarboxylic acids may be used alone or in combination of two or more.

[0100] 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, such as glycerin, trimethylolethane, trimethylolpropane, or pentaerythritol, in combination with the diol. The polyhydric alcohols may be used alone or in combination of two or more.

[0101] The polyhydric alcohol may have an aliphatic diol content of 80 mol % or more, preferably 90 mol % or more.

[0102] The crystalline polyester resin can be obtained by a known production method, for example, in the same manner as the amorphous polyester resin.

[0103] The crystalline polyester resin is preferably a polymer of an α,ω-straight-chain aliphatic dicarboxylic acid and an α,ω-straight-chain aliphatic diol.

[0104] 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 to 14 carbon atoms, more preferably 4 to 12 carbon atoms, and even more preferably 6 to 10 carbon atoms. Examples of the α,ω-linear aliphatic dicarboxylic acid 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.

[0105] 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 4 to 12 carbon atoms, and even more preferably 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.

[0106] As the polymer of an α,ω-linear aliphatic dicarboxylic acid and an α,ω-linear aliphatic diol, 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.

[0107] The content of the binder resin is preferably 40% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, and even more preferably 60% by mass to 85% by mass, based on the total mass of the toner particles.

[0108] -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 suitable dyes include pigments such as ultramarine blue, chalco oil 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.

[0109] The colorant may be surface-treated as needed, or may be used in combination with a dispersant. Furthermore, a plurality of colorants may be used in combination.

[0110] 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.

[0111] -Mold release agent- 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 montanic acid esters. The release agent is not limited to these, but it is preferable that the release agent contains an ester wax from the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant aggregation properties.

[0112] (Melting temperature of release agent) From the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant aggregation properties, the melting temperature Tm of the release agent is preferably 50°C or higher and 110°C or lower, more preferably 55°C or higher and 80°C or lower, and even more preferably 57°C or higher and 68°C or lower. The melting temperature Tm of the release agent is determined from a DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in the method for determining the melting temperature in JIS K7121:1987 "Method for measuring transition temperatures of plastics."

[0113] From the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant aggregation properties, the difference (Tm-Tg) between the melting temperature Tm of the release agent and the glass transition temperature Tg of the amorphous resin is preferably 0°C or higher and 20°C or lower, more preferably 0°C or higher and 15°C or lower, and even more preferably 0°C or higher and 10°C or lower.

[0114] From the viewpoint of obtaining a toner having excellent fixing properties and heat-resistant aggregation properties, the content of the release agent relative to the total amount of toner particles is preferably 0.1% by mass or more and 15% by mass or less, more preferably 0.2% by mass or more and 10% by mass or less, and even more preferably 0.5% by mass or more and 4% by mass or less.

[0115] -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.

[0116] [External additives] Examples of external additives include inorganic particles, such as 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.

[0117] The surfaces of inorganic particles as external additives are preferably subjected to a hydrophobic treatment. The hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment 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 hydrophobic treatment agent is usually, for example, 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the inorganic particles.

[0118] 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 particles of fluorine-based polymers).

[0119] The amount of the external additive added is preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2.0% by mass or less, based on the toner particles.

[0120] [Toner manufacturing method] The toner according to this exemplary embodiment is obtained by producing toner particles and then externally adding an external additive to the toner particles.

[0121] The toner particles may be produced by any of a dry production method (for example, a kneading and pulverization method) and a wet production method (for example, an aggregation and coalescence method, a suspension polymerization method, a dissolution and suspension method). There are no particular limitations on these production methods, and any known production method may be used.

[0122] Among the above-mentioned manufacturing methods, the kneading and pulverization method is preferred as a manufacturing method for the toner according to the present embodiment, since it is easy to impart highly uniform thermal properties to each toner particle because multiple binder resins are easily compatible at the molecular level, and it is easy to form an amorphous shape that is advantageous for heat-resistant aggregation.

[0123] An example of a method for producing toner particles by the kneading and pulverizing method will be described below. The kneading and pulverizing method is a method for producing toner particles by, for example, melting and kneading a binder resin containing an amorphous resin and a crystalline resin with a colorant, followed by pulverizing and classifying the mixture. In the kneading and pulverizing method, toner particles are produced through, for example, a kneading step for melting and kneading components containing the binder resin and the colorant, a cooling step for cooling the molten and kneaded mixture, a pulverizing step for pulverizing the cooled kneaded mixture, and a classification step for classifying the pulverized mixture.

[0124] Each step of the kneading and pulverizing method will be described in detail below.

[0125] -Kneading process- The kneading step is a step in which a binder resin including an amorphous resin and a crystalline resin and a component including an oligomer are melt-kneaded to obtain a kneaded product. Examples of kneaders used in the kneading step include a three-roll type, a single-screw type, a twin-screw type, and a Banbury mixer type. The melting temperature may be determined depending on the types and compounding ratios of the binder resin and oligomer to be kneaded.

[0126] -Cooling process- The cooling step is a step of cooling the kneaded material formed in the kneading step. In the cooling step, for example, the kneaded material is cooled from the temperature at the end of the kneading step to 40° C. or less at an average temperature decreasing rate of 15° C. / sec or less, which facilitates the growth of domains of the crystalline resin in the kneaded material. The average temperature decreasing rate refers to the average rate at which the temperature of the kneaded material is decreased from the temperature at the end of the kneading step to 40°C.

[0127] Examples of the cooling method in the cooling step include a method using a rolling roll through which cold water or brine is circulated and a pinching cooling belt, etc. When cooling is performed by the above method, the cooling rate is determined by the speed of the rolling roll, the flow rate of brine, the supply amount of the kneaded material, the slab thickness of the kneaded material when rolling, etc.

[0128] -Crushing process- The kneaded product cooled in the cooling step is pulverized in the pulverization step to form particles. In the pulverization step, for example, a mechanical pulverizer, a jet pulverizer, or the like is used. Here, before pulverization, the kneaded material may be heated to a temperature that does not exceed the melting point of the crystalline resin (for example, below the melting temperature of the crystalline resin (melting temperature -15°C)). This makes it easier for the domains of the crystalline resin in the kneaded material to grow.

[0129] -Classification process- The pulverized product (particles) obtained in the pulverization step may be classified in a classification step, if necessary, to obtain toner particles having a desired average particle size. In the classification process, conventional centrifugal classifiers, inertial classifiers, etc. are used to remove fine particles (particles smaller than the target particle size range) and coarse particles (particles larger than the target particle size range).

[0130] -Hot air treatment process- After the classification step, if necessary, hot air treatment may be carried out in a hot air treatment step in order to obtain toner particles with a desired circularity.

[0131] The toner according to this embodiment is produced by, for example, adding an external additive to the obtained dry toner particles and mixing them. The mixing can be carried out using, for example, a V blender, a Henschel mixer, a Loedige mixer, or the like. Furthermore, if necessary, coarse particles may be removed from the toner using a vibrating sieve, an air sieve, or the like.

[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 this embodiment may be a one-component developer containing only the toner according to this embodiment, or may be a two-component developer containing the toner mixed with a carrier.

[0133] The carrier is not particularly limited, and examples thereof include known carriers, such as coated carriers in which the surface of a core material made of magnetic powder is coated with a coating resin, magnetic powder dispersion carriers in which magnetic powder is dispersed and blended in a matrix resin, and resin-impregnated carriers 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 magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0135] Examples of coating resins and matrix resins 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 resins containing organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenolic resins, and epoxy resins. The coating resin and the matrix resin may contain other additives such as conductive particles. Examples of 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, the method of coating the surface of the core material with a coating resin includes a method of coating with a solution for forming a coating layer, in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be selected taking into consideration the coating resin to be used, its applicability, 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 the 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 mixing ratio (mass ratio) of toner to 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 and an 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 unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the surface of the charged image carrier, a developing unit that contains an electrostatic image developer and develops the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer, a transfer unit that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing unit that fixes 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] The image forming apparatus according to this embodiment carries out an image forming method (the image forming method according to this embodiment) that 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 that directly transfers a toner image formed on the surface of an image carrier to a recording medium; an intermediate transfer type apparatus that primarily transfers a toner image formed on the surface of an image carrier to the surface of an intermediate transfer medium, and then secondarily transfers the toner image transferred to the surface of the intermediate transfer medium to the surface of a recording medium; an apparatus equipped with a cleaning means that cleans the surface of the image carrier after the transfer of the toner image but before charging; and an apparatus equipped with a discharging means that irradiates the surface of the image carrier with discharging light to discharge it after the transfer of the toner image but before charging. In the case of an intermediate transfer type device, the transfer means is configured to have, 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 the 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 equipped with developing means that accommodates 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 other parts will be omitted.

[0143] FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus according to this embodiment. The image forming apparatus shown in Figure 1 includes first through fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming means) that output images in the colors 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 side by side horizontally spaced a predetermined distance apart from one another. Note that these units 10Y, 10M, 10C, and 10K may also 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 serving as an intermediate transfer body extends through each unit. The intermediate transfer belt 20 is wound around a drive roll 22 and a support roll 24 that are spaced apart from each other and arranged from left to right in the drawing, and is configured to run in a direction from the first unit 10Y to the fourth unit 10K. 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), thereby applying tension 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. In addition, 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, which forms a yellow image and is disposed upstream in the direction of travel of the intermediate transfer belt, will be described here as a representative. Note that parts equivalent to those of the first unit 10Y are given reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y), and descriptions of the second to fourth units 10M, 10C, and 10K will be omitted.

[0146] The first unit 10Y has a photoreceptor 1Y that acts as an image carrier. Around the photoreceptor 1Y, there are arranged in this order: a charging roll (an example of a charging means) 2Y that charges the surface of the photoreceptor 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 photoreceptor cleaning device (an example of a cleaning means) 6Y that removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer. The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20 and is positioned opposite the photoreceptor 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] The operation of forming a yellow image in first unit 10Y will be described below. First, prior to operation, the surface of the photosensitive member 1Y is charged to a potential of −600V to −800V by the charging roll 2Y. The photoconductor 1Y has conductivity (for example, volume resistivity at 20°C: 1×10 -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate with a resistivity of Ωcm or less. This photosensitive layer normally has a high resistance (the resistance of ordinary resins), but when irradiated with a laser beam 3Y, the resistivity of the irradiated portion changes. Therefore, a laser beam 3Y is output to the charged surface of the photosensitive element 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 photosensitive element 1Y, thereby forming an electrostatic charge image of a yellow image pattern on the surface of the photosensitive element 1Y.

[0148] An electrostatic image is an image formed on the surface of the photosensitive element 1Y by charging it; the laser beam 3Y reduces the resistivity of the irradiated portion of the photosensitive layer, causing the charged charges on the surface of the photosensitive element 1Y to flow, while the charges remain in the portions not irradiated by the laser beam 3Y, forming a so-called negative latent image. The electrostatic image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic image on the photoreceptor 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 containing, for example, at least yellow toner and a carrier. The yellow toner is frictionally 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 photoreceptor 1Y. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner electrostatically adheres to the discharged latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. The photoreceptor 1Y on which the yellow toner image has been formed continues to travel at a predetermined speed, and the toner image developed on the photoreceptor 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 to the primary transfer roll 5Y acts on the toner image, causing the toner image on the photoreceptor 1Y to be 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 photoreceptor 1Y is removed and collected by the photoreceptor cleaning device 6Y.

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

[0152] The intermediate transfer belt 20, onto which the four-color toner images have been multiplex-transferred through the first to fourth units, reaches a secondary transfer section composed of the intermediate transfer belt 20, a support roll 24 in contact with 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, recording paper (an example of a recording medium) P is fed via a supply mechanism into the gap between the secondary transfer roll 26 and the intermediate transfer belt 20 at a predetermined timing, and a secondary transfer bias is applied to the support roll 24. The transfer bias applied at this time has a negative polarity, the same as the negative polarity of the toner. Electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image on the intermediate transfer belt 20 onto the recording paper P. The secondary transfer bias at this time is determined according to resistance detected by resistance detection means (not shown) that detects resistance in the secondary transfer section, and is voltage-controlled.

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

[0154] Examples of the recording paper P onto which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, etc. In addition to the recording paper P, examples of the recording medium include overhead projector sheets and the like. 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 plain paper is coated with resin or the like, or art paper for printing, is preferably used.

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

[0156] <Process cartridges / toner cartridges> The process cartridge according to this embodiment will be described. The process cartridge according to this embodiment is a process cartridge that is detachably attached to an image forming apparatus and that contains the electrostatic image developer according to this embodiment and 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.

[0157] The process cartridge according to this embodiment is not limited to the above configuration, but may also be configured to include a developing device and, if 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. Note that only the main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0159] FIG. 2 is a schematic diagram showing the configuration of the process cartridge according to the present embodiment. The process cartridge 200 shown in FIG. 2 is configured to integrally combine and hold a photosensitive member 107 (an example of an image carrier), a charging roll 108 (an example of a charging means) provided around the photosensitive member 107, a developing device 111 (an example of a developing means), and a photosensitive member cleaning device 113 (an example of a cleaning means), which are held by a housing 117 provided with, for example, mounting rails 116 and an opening 118 for exposure, and is made 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 developing devices 4Y, 4M, 4C, and 4K are connected to the toner cartridges corresponding to each developing device (color) by toner supply pipes (not shown). When the toner stored in a toner cartridge runs low, the toner cartridge is replaced. [Example]

[0162] Hereinafter, 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 Polymer A> The materials shown in Table 1 and 40 parts of tin(II) 2-ethylhexanoate were placed in a 5-liter four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple in the amounts shown in Table 1. The temperature was raised to 235°C under a nitrogen atmosphere and the reaction was carried out until the reaction rate reached 60%. The reaction was then carried out at 8 kPa until the softening temperature shown in Table 1 was reached, after which the reaction mixture was cooled to room temperature to obtain Polymer A, an amorphous resin. The weight-average molecular weight, glass transition temperature, and softening temperature of the obtained Polymer A are shown in Table 1. The reaction rate refers to the value calculated by dividing the amount of reaction water produced by the theoretical amount of water produced by 100.

[0164] <Synthesis of Polymers B, C, G and H> Polymers B, C, G and H, which are amorphous resins, were obtained in the same manner as for Polymer A, except that the materials, amounts and reaction rates were as shown in Table 1.

[0165] <Synthesis of Polymer D> The materials other than trimellitic anhydride shown in Table 1 and 40 parts of tin(II) 2-ethylhexanoate were placed in a 5-liter four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple in the amounts shown in Table 1. The mixture was heated to 235°C under a nitrogen atmosphere and reacted until a reaction rate of 88% was reached. The reaction was then continued for 1 hour at 8 kPa. The temperature was then lowered to 210°C and the pressure was returned to normal (101.3 kPa). Trimellitic anhydride was then added to the reaction system, and the reaction was continued for another hour at 210°C and normal pressure. The reaction was then continued at 15 kPa until the softening temperature shown in Table 1 was reached. The reaction mixture was then cooled to room temperature to obtain Polymer D, an amorphous resin.

[0166] <Synthesis of Polymers E, F, I, and J> Polymers E, F, I and J, which are amorphous resins, were obtained in the same manner as for Polymer D, except that the materials, amounts and reaction rates were as shown in Table 1.

[0167] <Synthesis of Polymer K> A reaction vessel was charged with 200 parts of toluene and heated to reflux temperature. A mixture of 84 parts of styrene monomer, 16 parts of butyl acrylate, and 5 parts of di-tert-butyl peroxide was added dropwise to the reaction vessel at 100°C over 2 hours. After that, under toluene reflux, the polymerization reaction was completed, and the toluene solvent was removed to obtain Polymer K, an amorphous resin. The obtained amorphous resin Polymer K had a softening temperature of 92°C, a glass transition temperature of 50°C, and a weight average molecular weight of 32,000.

[0168] <Synthesis of Polymer L> A reaction vessel was charged with 200 parts of degassed water, and 75 parts of styrene monomer, 25 parts of 2-ethylhexyl acrylate, and 0.5 parts of 1,1'-azobiscyclohexanecarbonitrile were added to prepare a suspension dispersion. The suspension dispersion was heated to 80°C under a nitrogen atmosphere. This temperature was maintained for 24 hours to complete the polymerization reaction. After the reaction system was cooled to room temperature, the spherical polymer particles produced by the polymerization reaction were filtered out. The filtered polymer particles were thoroughly washed with water, dehydrated, and dried to obtain Polymer L. The obtained Polymer L had a softening temperature of 155°C, a glass transition temperature of 72°C, and a weight-average molecular weight of 956,000.

[0169] <Synthesis of polymer cA> A heated and dried three-neck flask was charged with 225 parts of 1,10-dodecanedioic acid, 174 parts of 1,10-decanediol, and 0.8 parts of dibutyltin oxide as a catalyst. The air in the three-neck flask was then purged with nitrogen under reduced pressure to create an inert atmosphere. The reaction was then mechanically stirred at 180°C for 5 hours under reflux. During the reaction, water generated in the reaction system was distilled off. The temperature was then gradually increased to 230°C under reduced pressure. After stirring for 2 hours, the mixture became viscous. The molecular weight was confirmed by GPC. When the weight-average molecular weight reached 17,500, the vacuum distillation was stopped to obtain polymer cA. The melting point of the resulting polymer cA was 74°C.

[0170] <Preparation of Binder Resins 1 to 10 and c1 to c6> In the combination shown in Table 2, 70 parts of the first polymer and 30 parts of the second polymer were added to 200 parts of xylene and stirred. Next, the reaction vessel was heated to 60°C to completely dissolve the added polymer. Subsequently, heating and stirring were continued at the same temperature for about 2 hours, and then the xylene was removed to obtain the binder resin of each example. In Table 2, "-" indicates that the binder resin does not contain the first polymer or the second polymer, that is, the polymer component is one type.

[0171] <Preparation of binder resin 11> A binder resin 11 was obtained in the same manner as in Example 1, except that the materials contained 67.5 parts of the first polymer, 27.5 parts of the second polymer, and 5 parts of polymer cA.

[0172] <Preparation of binder resin c7> Binder resin c7 was obtained in the same manner as in Example 1, except that the materials contained 65 parts of the first polymer, 15 parts of the second polymer, and 20 parts of polymer cA.

[0173] In Table 1, BPA-PO refers to the "propylene oxide adduct of bisphenol A (average number of moles added: 2.2 mol)" and BPA-EO refers to the "ethylene oxide adduct of bisphenol A (average number of moles added: 2.2 mol)."

[0174] Example 1 Binder resin 1: 81 parts Carbon black (BPL, manufactured by Cabot Corporation): 6 parts Ester wax (WEP-9, NOF Corporation): 3 parts The mixture of the above materials was melt-kneaded for 5 minutes in a Banbury mixer, then rolled / cooled, coarsely pulverized in a hammer mill, finely pulverized in a jet mill, and classified in an air classifier to obtain toner particles with a volume average particle size of 9.0 μm. 100 parts by weight of these toner particles were mixed with 1.0 part by weight of titanium oxide and 0.3 part by weight of hydrophobic silica in a Henschel mixer to obtain Toner 1.

[0175] [Examples 2 to 14, Comparative Examples C1 to C7] The toners of each example were obtained in the same manner as in Example 1, except that the type, structure, and glass transition temperature of the binder resin, the type, amount, and melting temperature of the release agent, and the properties of the toner particles were set to the specifications shown in Tables 3 and 4.

[0176] The following properties were measured for the obtained toner of each example according to the methods already described. The results are shown in Tables 3 and 4. The maximum peak Ma in the molecular weight range of 2500 to 8000 Molecular weight: Minimum value (mm) The maximum peak Mb in the molecular weight range of 280,000 to 900,000 The area A of the differential molecular weight distribution curve having a molecular weight of 100 or more and less than the minimum value Mm The area B of the differential molecular weight distribution curve that is equal to or greater than the minimum value Mm and has a molecular weight of 10,000,000 or less ·Area ratio A / B Half width of maximum peak Ma Half-width of maximum peak Mb The ratio of the height Ha of the maximum peak Ma to the height Hb of the maximum peak Mb (Ha / Hb) The relationship between the maximum peak Ma, the minimum value Mm, and the maximum peak Mb is (Mb-Mm) / (Mm-Ma). · Glass transition temperature Tg of binder resin Melting temperature of the release agent The difference between the melting temperature Tm of the release agent and the glass transition temperature Tg of the amorphous resin (Tm-Tg) Average circularity of toner particles Small diameter number particle size distribution index of toner particles (lower GSDp) Ratio of toluene insolubles to toner particles

[0177] In the table, "blank", "-" or "0" indicates that the respective material is not included. In the table, the notation "none" in the item Ma indicates that "no peak is observed in the molecular weight range of 2500 or more and 8000 or less." In the table, the notation "none" in the item Mm indicates that "no minimum value is observed in the range of molecular weight exceeding 8,000 and less than 280,000." In the table, the notation "none" in the item Mb indicates that "no peak is observed in the molecular weight range of 280,000 or more and 900,000 or less." In the tables, the numerical values ​​shown in the items Ma and Mb for comparative examples indicate the values ​​of peaks observed in the differential molecular weight distribution curve, and include some peaks outside the range of molecular weights of 2500 or more and 8000 or less, or the range of molecular weights of 10,000,000 or more and the minimum value Mm or more. In the tables, the numerical value shown in the item Mm for comparative examples indicates the minimum value between the valleys of the multiple peaks when multiple peaks are observed in the differential molecular weight distribution curve.

[0178] [Table 1]

[0179] [Table 2]

[0180] <Evaluation> (Fixability: Evaluation of image strength) 1.6 parts of methyl methacrylate-perfluorooctyl ethyl acrylate copolymer was added with 14 parts of toluene and dispersed with a sand mill to obtain a dispersion. Next, the dispersion and 100 parts of ferrite particles (volume average particle size 50 μm) were placed in a vacuum degassing kneader and stirred at 60°C for 30 minutes, after which the toluene was distilled off under reduced pressure to obtain a resin-coated carrier. The copolymerization ratio of the methyl methacrylate-perfluorooctyl ethyl acrylate copolymer was 85:15.

[0181] 36 parts of the toner of each example and 414 parts of the resin-coated carrier were placed in a V blender and stirred for 20 minutes, and then sieved through a sieve with 212 μm openings to prepare the developer of each example.

[0182] Each example developer was left for 12 hours in an environment of 25°C temperature and 25% RH, after which an image forming apparatus (modified 700 Digital Color Press manufactured by Fuji Xerox Co., Ltd.) was prepared and the developer was installed in the developing apparatus. Each example toner was also placed in a replenishment developer storage chamber. Then, in an environment of 15°C temperature and 10% RH humidity, 100 images of Test Chart No. 4 published by the Imaging Society of Japan were printed consecutively on printing paper (C2r paper manufactured by Fuji Xerox Co., Ltd.). The fixing temperature was 160°C. The image areas with the lowest image density were cut out from the first and 100th sheets of the output images obtained and accurately weighed. The cut-out and weighed images with low image density were then rubbed with Kimwipes (manufactured by Nippon Paper Crecia Co., Ltd.) and reweighed. The weights of the images before and after rubbing with Kimwipes were compared, and the weight loss rate was calculated using the following formula: Reduction rate (%) = (weight after rubbing with Kimwipe) ÷ (weight before rubbing with Kimwipe) × 100 The obtained reduction rate was evaluated according to the following evaluation criteria. A reduction rate of 97% or more was considered acceptable. The results are shown in Tables 3 and 4.

[0183] -Evaluation criteria- A: The reduction rate is 0% for both the first and 100th sheets, and the difference is not visible to the naked eye. B: The reduction rate is 0% for both the 1st and 100th sheets, but the reduction in image density is visually recognizable for the 100th sheet. C: The reduction rate of one or more of the 1st and 100th sheets is 98% or more but less than 100% D: The reduction rate of one or more of the 1st and 100th sheets is 97% or more but less than 98% E: The reduction rate of one or more of the 1st and 100th sheets is less than 97%

[0184] (Evaluation of heat resistance) Using a powder tester (manufactured by Hosokawa Micron Corporation), sieves with openings of 56 μm, 45 μm, and 37 μm were placed on a vibration table so that they were stacked in order of narrowest opening, and 2 g of each example toner sample was placed on the set sieve. The input voltage to the vibration table was set to 15 V, the vibration table amplitude was adjusted to be in the range of 70 to 90 μm, and vibration was applied for 90 seconds. Thereafter, the mass of the sample remaining on each sieve was measured, and the degree of cohesion was calculated using the following formula. Cohesion degree (%)=(W56 / 2)×100+(W45 / 2)×100×0.6+(W38 / 2)×100×0.2 In the formula, W56 represents the mass (g) of the sample remaining on the sieve with a mesh size of 56 μm, W45 represents the mass (g) of the sample remaining on the sieve with a mesh size of 45 μm, and W38 represents the mass (g) of the sample remaining on the sieve with a mesh size of 38 μm. The obtained aggregation degree values ​​were evaluated according to the following evaluation criteria. The results are shown in Tables 3 and 4.

[0185] -Evaluation criteria- A: Thermal cohesion degree is 30% or less B: Thermal cohesion degree: over 30% and less than 40% C: Thermal cohesion degree: over 50% and less than 60% D: Thermal cohesion degree: over 60% and below 70% E: Thermal cohesion over 70%

[0186] [Table 3]

[0187] [Table 4]

[0188] From the above results, it can be seen that the present example is superior to the comparative example in both fixability and heat-resistant aggregation. [Explanation of symbols]

[0189] 1Y, 1M, 1C, 1K Photoconductor (an example of an image carrier) 2Y, 2M, 2C, 2K Charging roll (an example of charging means) 3. Exposure device (an example of 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 Drive Roll 24 Support Roll 26 Secondary transfer roll (an example of a secondary transfer means) 28 Fixing device (an example of fixing means) 30 Intermediate transfer body cleaning device P Recording paper (an example of a recording medium) 107 Photosensitive body (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 transfer means) 113 Photosensitive drum cleaning device (an example of cleaning means) 115 Fixing device (an example of fixing means) 116 Mounting Rail 117 Cabinet 118 Exposure opening 200 Process Cartridge 300 Recording paper (an example of a recording medium)

Claims

1. The toner particles contain a binder resin containing an amorphous resin in an amount of 90% by mass or more, In the differential molecular weight distribution curve of the tetrahydrofuran soluble fraction obtained by gel permeation chromatography, The maximum peak Ma is in the molecular weight range of 2500 to 8000. A minimum molecular weight Mm in the range of more than 8,000 and less than 280,000; and It has a maximum peak Mb in the molecular weight range of 280,000 or more and 900,000 or less, The area of ​​the differential molecular weight distribution curve for a molecular weight of 100 or more and less than the minimum value Mm is A, When the area of ​​the differential molecular weight distribution curve that is equal to or greater than the minimum value Mm and has a molecular weight of 10,000,000 or less is defined as B, The area ratio A / B of the two is 5.5 or more and 10 or less, The toner for developing electrostatic images, wherein the relationship (Mb-Mm) / (Mm-Ma) between the maximum peak Ma, the minimum value Mm and the maximum peak Mb is 1.0 or more and 2.4 or less.

2. The toner particles contain a binder resin containing an amorphous resin in an amount of 90% by mass or more, In the differential molecular weight distribution curve of the tetrahydrofuran soluble fraction obtained by gel permeation chromatography, The maximum peak Ma is in the molecular weight range of 2500 to 8000. A minimum molecular weight Mm in the range of more than 8,000 and less than 280,000; and It has a maximum peak Mb in the molecular weight range of 280,000 or more and 900,000 or less, The half width of the maximum peak Ma is 12,000 or more and 20,000 or less, The half width of the maximum peak Mb is 320,000 or more and 500,000 or less, and 2. The toner for developing electrostatic images according to claim 1, wherein a ratio (Ha / Hb) of a height Ha of the maximum peak Ma to a height Hb of the maximum peak Mb is 2.7 or more and 6.0 or less.

3. 3. The toner for developing electrostatic images according to claim 1, wherein the toner particles further contain a release agent.

4. 4. The toner for developing electrostatic images according to claim 3, wherein the release agent contains an ester wax.

5. 5. The toner for developing electrostatic images according to claim 3, wherein the content of the release agent is 0.5% by mass or more and 4% by mass or less based on the toner particles.

6. 6. The toner for developing electrostatic images according to claim 3, wherein the melting temperature of the release agent is 57° C. or higher and 68° C. or lower.

7. 7. The toner for developing electrostatic images according to claim 3, wherein a difference (Tm-Tg) between a melting temperature Tm of the release agent and a glass transition temperature Tg of the amorphous resin is 0°C or more and 10°C or less.

8. 8. The toner for developing electrostatic images according to claim 1, wherein the toner particles have an average circularity of 0.915 or more and 0.950 or less.

9. 9. The toner for developing electrostatic images according to claim 1, wherein the toner particles have a small diameter number particle size distribution index (lower GSDp) of 1.33 or less.

10. A toner particle containing a binder resin containing an amorphous resin at 90% by mass or more, In the differential molecular weight distribution curve of the tetrahydrofuran soluble fraction obtained by gel permeation chromatography, The maximum peak Ma is in the molecular weight range of 2500 to 8000. A minimum molecular weight Mm in the range of more than 8,000 and less than 280,000; and It has a maximum peak Mb in the molecular weight range of 280,000 or more and 900,000 or less, The area of ​​the differential molecular weight distribution curve for a molecular weight of 100 or more and less than the minimum value Mm is A, When the area of ​​the differential molecular weight distribution curve that is equal to or greater than the minimum value Mm and has a molecular weight of 10,000,000 or less is defined as B, The area ratio A / B of the two is 5.5 or more and 10 or less, The toner for developing electrostatic images has a toluene-insoluble content of 3% by mass or more and 8% by mass or less based on the toner particles.

11. The toner for developing electrostatic images according to any one of claims 1 to 10, wherein the amorphous resin comprises an amorphous polyester resin.

12. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 11.

13. A toner cartridge containing the toner for developing electrostatic images according to any one of claims 1 to 11, which is detachably mountable on an image forming apparatus.

14. 13. A process cartridge detachably mountable to an image forming apparatus, the process cartridge containing the electrostatic image developer according to claim 12 and comprising a developing means for developing an electrostatic image formed on a surface of an image carrier with the electrostatic image developer into a toner image.

15. 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 containing the electrostatic image developer according to claim 12 and 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 the 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:

Images