JP7844978B2 - Image forming apparatus and process cartridge - Google Patents

Description

This invention relates to an image forming apparatus and a process cartridge.

Patent Document 1 describes an image forming apparatus comprising a toner container containing an aggregate of toner particles to which lubricant particles have been added, an image carrier surface that circulates in a predetermined direction, an electrostatic latent image formed on the surface of the image carrier by charging the surface of the image carrier and irradiating the charged surface of the image carrier with exposure light, developing the electrostatic latent image to obtain a toner image by supplying toner particles contained in the toner container to the electrostatic latent image, and transferring the toner image to a predetermined transfer surface and finally fixing it on a recording medium to form an image consisting of a fixed toner image on the recording medium, wherein residual toner particles remaining on the surface of the image carrier after the toner image has been transferred to the transfer surface are scraped An image forming apparatus is disclosed, comprising a cleaning blade with a tip edge made of rubber material pressed against the surface of the image carrier, and a toner recovery means that returns residual toner particles scraped from the surface of the image carrier by the cleaning blade to the toner container. The cleaning blade is characterized by having a first portion, which constitutes the tip edge, made of rubber material whose 100% modulus at 23°C is in the range of 4 MPa to 18 MPa, and a second portion, which is the portion other than the first portion, made of rubber material whose 100% modulus at 23°C is lower than the aforementioned range.

Patent Document 2 discloses a toner comprising "a binder resin, a colorant, a wax, and resin fine particles, wherein the resin fine particles are made of a resin incompatible with the binder resin, have a glass transition temperature of 100 to 220°C, and an average particle size of 0.05 to 1 μm."

Patent No. 4788240 Japanese Patent Publication No. 2007-108591

Conventionally, an image forming apparatus (hereinafter also referred to as a specific image forming apparatus) is known, comprising: an electrophotographic photoreceptor; a charging device for charging the surface of the electrophotographic photoreceptor; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor; a developing device containing a developer including toner, which develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor using the developer to form a toner image; a cleaning device having a cleaning blade that cleans the surface of the electrophotographic photoreceptor by bringing a contact portion into contact with the surface of the electrophotographic photoreceptor; and a transfer device for transferring the toner image to the surface of a recording medium, wherein the cleaning blade has a contact portion and a substrate layer. In the above specific image forming apparatus, chipping of the cleaning blade in low temperature and low humidity environments and filming in high temperature and high humidity environments sometimes occurred.
Therefore, the object of the present invention is to provide an image forming apparatus in which both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments are suppressed, compared to the above-mentioned specific image forming apparatus in which the toner contains toner particles including a binder resin and resin particles, and an external additive, and the relationship between the content X (mass%) of resin particles relative to the toner particles and the 100% modulus α23 edge of the contact portion of the cleaning blade at 23°C (X/α23 edge) is less than 0.12 or greater than 7.5.

The above problems will be solved by the following means.

<1> Electrophotographic photoreceptor and
A charging device for charging the surface of the electrophotographic photoreceptor,
A static charge image forming apparatus for forming a static charge image on the surface of the charged electrophotographic photoreceptor,
A developing apparatus that contains a developer containing toner, and uses the developer to develop the electrostatic latent image formed on the surface of the electrophotographic photoreceptor to form a toner image,
A cleaning device having a cleaning blade that cleans the surface of the electrophotographic photoreceptor by bringing a contact portion into contact with the surface of the electrophotographic photoreceptor,
A transfer device for transferring the toner image onto the surface of a recording medium,
Equipped with,
The cleaning blade has a contact portion and a base material layer,
The toner comprises toner particles containing a binder resin and resin particles, and an external additive.
An image forming apparatus in which the relationship between the content X (mass%) of the resin particles relative to the toner particles and the 100% modulus α23 edge at 23°C of the contact portion of the cleaning blade satisfies 0.12 ≤ X / α23 edge ≤ 7.5.
<2> The image forming apparatus according to <1>, wherein the 100% modulus α23 edge of the contact portion of the cleaning blade at 23°C is 4 MPa or more and 18 MPa or less.
<3> The image forming apparatus according to <1> or <2>, wherein the 100% modulus α23base of the substrate layer of the cleaning blade at 23°C is lower than the 100% modulus α23edge of the contact portion at 23°C.
<4> The image forming apparatus according to any one of <1> to <3> above, wherein the content of the resin particles is 2% by mass or more and 30% by mass or less relative to the toner particles.
<5> The image forming apparatus according to any one of <1> to <4> above, wherein the relationship between the content X (mass%) of the resin particles relative to the toner particles and the 100% modulus α30 edge at 30°C of the contact portion of the cleaning blade satisfies 0.14 ≤ X / α30 edge ≤ 9.8.
<6> The image forming apparatus according to any one of <1> to <5>, wherein the number-average particle size of the resin particles is 60 nm or more and 300 nm or less.
<7> An image forming apparatus according to any one of <1> to <6>, wherein, in a dynamic viscoelasticity measurement of the resin particles when the temperature is raised by 2°C/min, the storage modulus G' in the range of 23°C to 80°C is 1 × ^10⁵ Pa or more and 5 × ^10⁷ Pa or less.
<8> The image forming apparatus according to <7>, wherein, in a dynamic viscoelasticity measurement of the components obtained by removing the resin particles from the toner particles when the temperature is raised by 2°C/min, the storage modulus G' in the range of 23°C to 50°C is 1 × ^10⁸ Pa or more, and the temperature at which the storage modulus G' reaches less than 1 × ^10⁵ Pa is 65°C to 90°C.
<9> In the dynamic viscoelasticity measurement of the toner, when the loss tangent tanδ at a temperature of 90°C and a strain of 1% is D1(90), the loss tangent tanδ at a temperature of 90°C and a strain of 50% is D50(90), the loss tangent tanδ at a temperature of 150°C and a strain of 1% is D1(150), and the loss tangent tanδ at a temperature of 150°C and a strain of 50% is D50(150),
D1(90), D50(90), D1(150), and D50(150) are each between 0.5 and 2.0.
The value of D50(150) - D1(150) is less than 1.5.
An image forming apparatus according to any one of <1> to <8> above, wherein the value of D50(90)-D1(90) is less than 0.5.
<10> The image forming apparatus according to any one of <1> to <9>, wherein the resin particles are crosslinked resin particles.
<11> The image forming apparatus according to <10>, wherein the crosslinked resin particles are styrene (meth)acrylic resin particles.
<12> The image forming apparatus according to any one of <1> to <11>, wherein the toner has silica particles as the external additive.
<13> The image forming apparatus according to <12>, wherein the toner has titanium oxide particles together with the silica particles as an external additive.
<14> The image forming apparatus according to any one of <1> to <13>, wherein the content of the external additive is 0.01% by mass or more and 5% by mass or less with respect to the toner particles.
<15> Electrophotographic photoreceptor and
A developing apparatus that contains a developer containing toner, and uses the developer to develop the electrostatic charge image formed on the surface of the electrophotographic photoreceptor to form a toner image,
A cleaning device having a cleaning blade that cleans the surface of the electrophotographic photoreceptor by bringing a contact portion into contact with the surface of the electrophotographic photoreceptor,
Equipped with,
The cleaning blade has the contact portion and the base material layer,
The toner comprises toner particles containing a binder resin and resin particles, and an external additive.
A process cartridge for attachment to and detachment from an image forming apparatus, wherein the relationship between the content X (mass%) of the resin particles relative to the toner particles and the 100% modulus α23edge at 23°C of the contact portion of the cleaning blade satisfies 0.12 ≤ X / α23edge ≤ 7.5.

According to the invention described in <1>, in the specific image forming apparatus, the toner contains toner particles including a binder resin and resin particles, and an external additive, and the relationship between the content X (mass%) of the resin particles relative to the toner particles and the 100% modulus α23 edge of the contact portion of the cleaning blade at 23°C (X/α23 edge) is less than 0.12 or greater than 7.5, compared to the case in which both chipping of the cleaning blade in a low-temperature, low-humidity environment and filming in a high-temperature, high-humidity environment are suppressed.
According to the invention of <2>, compared to the case where the 100% modulus α23 edge of the contact portion of the cleaning blade at 23°C is less than 4 MPa or more than 18 MPa, an image forming apparatus is provided in which both chipping of the cleaning blade in a low-temperature, low-humidity environment and filming in a high-temperature, high-humidity environment are suppressed.
According to the invention of <3>, compared to the case where the 100% modulus α23base of the base layer of the cleaning blade at 23°C is higher than the 100% modulus α23edge of the contact portion at 23°C, an image forming apparatus is provided in which both chipping of the cleaning blade in a low-temperature, low-humidity environment and filming in a high-temperature, high-humidity environment are suppressed.
According to the invention of <4>, compared to the case where the resin particle content is less than 2% by mass or more than 30% by mass relative to the toner particles, an image forming apparatus is provided in which both chipping of the cleaning blade in a low-temperature, low-humidity environment and filming in a high-temperature, high-humidity environment are suppressed.
According to the invention of <5>, compared to the case where the relationship between the content X (mass%) of the resin particles relative to the toner particles and the 100% modulus α30 edge of the contact portion of the cleaning blade at 30°C (X/α30 edge) is less than 0.13 or greater than 10, an image forming apparatus is provided in which both chipping of the cleaning blade in a low-temperature, low-humidity environment and filming in a high-temperature, high-humidity environment are suppressed.

According to the invention described in <6>, an image forming apparatus is provided in which both chipping of the cleaning blade in a low-temperature, low-humidity environment and filming in a high-temperature, high-humidity environment are suppressed, compared to the case where the number-average particle size of the resin particles exceeds 300 nm.
According to the invention of <7>, compared to the case in which resin particles are not contained, or in the case in which the storage modulus G' of the resin particles at 80°C is less than 1 × ^10⁵ Pa, an image forming apparatus is provided in which both chipping of the cleaning blade in a low-temperature, low-humidity environment and filming in a high-temperature, high-humidity environment are suppressed.
According to the invention of <8>, compared to the case where the temperature at which the storage modulus G' of the component obtained by removing resin particles from toner particles reaches less than 1 × ^10⁵ Pa exceeds 90°C, an image forming apparatus is provided in which both chipping of the cleaning blade in a low temperature and low humidity environment and filming in a high temperature and high humidity environment are suppressed.
According to the invention of <9>, compared to cases where any of D1(90), D50(90), D1(150), and D50(150) is less than 0.5 or greater than 2.0, where the value of D50(150)-D1(150) is 1.5 or more, or where the value of D50(90)-D1(90) is 0.5 or more, an image forming apparatus is provided in which both chipping of the cleaning blade in a low-temperature, low-humidity environment and filming in a high-temperature, high-humidity environment are suppressed.
According to the invention of <10>, an image forming apparatus is provided in which both chipping of the cleaning blade in a low-temperature, low-humidity environment and filming in a high-temperature, high-humidity environment are suppressed, compared to the case in which the resin particles are non-crosslinked resin particles.
According to the invention of <11>, compared to the case where the resin particles are polyester resin particles, an image forming apparatus is provided in which both chipping of the cleaning blade in a low-temperature, low-humidity environment and filming in a high-temperature, high-humidity environment are suppressed.
According to the invention of <12> or <13>, an image forming apparatus is provided in which both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments are suppressed, compared to the case in which titanium dioxide alone is used as an external additive.
According to the invention of <14>, compared to cases where the content of the external additive is less than 0.01% by mass or more than 5% by mass relative to the toner particles, an image forming apparatus is provided in which both chipping of the cleaning blade in a low-temperature, low-humidity environment and filming in a high-temperature, high-humidity environment are suppressed.

According to the invention described in <15>, a process cartridge for attachment to an image forming apparatus is provided in which the toner contains toner particles including a binder resin and resin particles, and an external additive, and the relationship between the content X (mass%) of the resin particles relative to the toner particles and the 100% modulus α23 edge of the contact portion of the cleaning blade at 23°C (X/α23 edge) is less than 0.12 or greater than 7.5. Compared to this case, the process cartridge suppresses both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments.

This is a schematic diagram showing an example of an image forming apparatus according to this embodiment. This is a schematic diagram showing an example of a cleaning blade in this embodiment.

The following describes an example of the present invention. These descriptions and examples are illustrative and do not limit the scope of the invention.
In numerical ranges described stepwise within this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Furthermore, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values shown in the examples.
In this specification, (meth)acrylic means both acrylic and methacrylic.

In this specification, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, provided that their intended purpose is achieved.
Each component may contain multiple types of the relevant substance.
When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition.

[Image forming apparatus]
The image forming apparatus according to this embodiment comprises an electrophotographic photoreceptor (hereinafter also referred to as "photoreceptor"), a charging device for charging the surface of the electrophotographic photoreceptor, an electrostatic image forming device for forming an electrostatic image on the charged surface of the electrophotographic photoreceptor, a developing device containing a developer including toner and using the developer to develop the electrostatic latent image formed on the surface of the electrophotographic photoreceptor to form a toner image, a cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photoreceptor by bringing a contact portion into contact with the surface of the electrophotographic photoreceptor, and a transfer device for transferring the toner image to the surface of a recording medium, wherein the cleaning blade has a contact portion containing a first rubber material and a substrate layer containing a second rubber material. Hereinafter, the image forming apparatus having the above configuration will also be referred to as a specific image forming apparatus.
The image forming apparatus according to this embodiment has toner particles containing a binder resin and resin particles, and an external additive, wherein the relationship between the content X (mass%) of the resin particles relative to the toner particles and the 100% modulus α23 edge at 23°C of the contact portion of the cleaning blade satisfies 0.12 ≤ X / α23 edge ≤ 7.5. Hereinafter, the toner having the above configuration will also be referred to as toner.

Conventionally, when forming images using specific image forming apparatuses, chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments sometimes occurred. While the exact cause is not entirely clear, the following is a possible explanation.

Conventional toners with low-temperature fixing properties exhibit significant changes in toner properties with changes in temperature and humidity. For example, when such toner is housed in an image forming apparatus equipped with a cleaning device that includes a cleaning blade having a contact portion containing a first rubber material and a substrate layer containing a second rubber material, as in the specific image forming apparatus described above, under low temperature and low humidity conditions (e.g., 10°C 15% RH), the viscoelasticity of the toner becomes too low, and the amount of external additive released tends to increase. In this case, if the 100% modulus of the contact portion of the cleaning blade is high, the blade will be in contact with the photoreceptor at the tip, causing the released external additive to excessively slip through the blade, which can lead to chipping of the blade tip. Furthermore, under high temperature and high humidity conditions (e.g., 30°C 90% RH), the viscoelasticity of the toner becomes too high, and the adhesion force of the toner to the photoreceptor tends to increase. In this case, if the 100% modulus of the contact portion of the cleaning blade is low, the ability to remove deposits from the photoreceptor tends to decrease. As a result, when images were repeatedly formed, streaky image defects sometimes occurred due to toner particles slipping through the cleaning blade and being stretched in a streaky manner in the direction of transport of the recording medium.

On the other hand, the image forming apparatus according to this embodiment, with the above configuration, suppresses chipping of the cleaning blade in low-temperature, low-humidity environments and the occurrence of filming in high-temperature, high-humidity environments. While the mechanism of action is not entirely clear, it is presumed to be as follows.

The toner contained in the image forming apparatus according to this embodiment comprises toner particles containing a binder resin and resin particles, and an external additive. The relationship between the content X (mass%) of the resin particles relative to the toner particles and the 100% modulus α23edge at 23°C of the contact portion of the cleaning blade satisfies 0.12 ≤ X / α23edge ≤ 7.5. In other words, since the toner particles contain a certain amount or more of resin particles, even in regions where the viscoelasticity of the toner is low, if the 100% modulus at 23°C of the contact portion of the cleaning blade is below a certain level, the cleaning blade is less likely to press excessively against the photoreceptor. Therefore, the external additive does not become excessively free even in low-temperature, low-humidity environments, and the removal efficiency by the external additive is more easily maintained. As a result, it is believed that the occurrence of chipping of the cleaning blade tip due to some of the excessively free external additive slipping through the cleaning blade is also suppressed.
Furthermore, because the amount of resin particles contained in the toner particles is below a certain level, even in regions where the toner has high viscoelasticity, as long as the 100% modulus at 23°C of the contact area of the cleaning blade is above a certain level, the adhesion force of the toner to the photoreceptor surface will not become excessively high. Therefore, even in high-temperature and high-humidity environments, toner particles are less likely to slip through the cleaning blade. As a result, it is believed that streaky image defects are suppressed even when repeatedly forming images.

[Specific examples of image forming apparatus]
Herein, the image forming apparatus according to this embodiment is applicable to well-known image forming apparatuses such as: a direct transfer apparatus that directly transfers a toner image formed on the surface of a photoreceptor to a recording medium; an intermediate transfer apparatus that first transfers a toner image formed on the surface of a photoreceptor to the surface of an intermediate transfer body, and secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; and an apparatus equipped with a static elimination device that irradiates the surface of the photoreceptor with static elimination light to eliminate static charge after the transfer of the toner image and before charging.

In the case of an intermediate transfer method apparatus, the transfer apparatus may include, for example, an intermediate transfer body on which a toner image is transferred; a primary transfer apparatus that first transfers the toner image formed on the surface of the photoreceptor to the surface of the intermediate transfer body; and a secondary transfer apparatus that secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

The image forming apparatus according to this embodiment may, for example, have a cartridge structure (process cartridge) in which at least a portion including a photoreceptor, a developing device, and a cleaning device is attached to and detached from the image forming apparatus.

The following describes an example of an image forming apparatus according to this embodiment, but it is not limited to this example. The main parts shown in the figure will be described, and other parts will be omitted from the explanation.

Figure 1 is a schematic diagram showing an example of an image forming apparatus according to this embodiment.
As shown in Figure 1, the image forming apparatus 10 according to this embodiment is provided with, for example, a photoreceptor 12. The photoreceptor 12 is cylindrical and is connected to a drive unit 27 such as a motor via a drive force transmission member (not shown) such as a gear, and is rotationally driven by the drive unit 27 around a rotation axis indicated by a black dot. In the example shown in Figure 1, it is rotationally driven in the direction of arrow A.

Around the photoreceptor 12, for example, a charging device 15, an electrostatic image forming device 16, a developing device 18, a transfer device 31, a cleaning device 22, and a static elimination device 24 are arranged in order along the rotational direction of the photoreceptor 12. The image forming apparatus 10 also includes a fixing device 26 having a fixing member 26A and a pressing member 26B positioned in contact with the fixing member 26A. Furthermore, the image forming apparatus 10 has a control device 36 that controls the operation of each device (each part). Note that the unit including the photoreceptor 12, charging device 15, electrostatic image forming device 16, developing device 18, transfer device 31, and cleaning device 22 constitutes the image forming unit.

In the image forming apparatus 10, at least the photoreceptor 12, the developing device 18, and the cleaning device 22 may be provided as a process cartridge integrated with other devices.

The following describes the details of each component (part) of the image forming apparatus 10.

[Photoreceptor]
The photoreceptor 12 has a photosensitive layer.
The photosensitive layer may be a single-layer photosensitive layer that integrates the functions of a charge generating material and a charge transport material within the same photosensitive layer, or it may be a multilayer photosensitive layer with separate functions having a charge generating layer and a charge transport layer. When the photosensitive layer is a multilayer photosensitive layer, the order of the charge generating layer and the charge transport layer is not particularly limited, but it is preferable that the photoreceptor has a configuration in which the charge generating layer, the charge transport layer and the surface protective layer are arranged in this order on a conductive substrate. The photoreceptor may also contain layers other than these.

[Charging device]
The charging device 15 charges the surface of the photoreceptor 12. The charging device 15 includes, for example, a charging member 14 that is provided in contact with or without contact with the surface of the photoreceptor 12 to charge the surface of the photoreceptor 12, and a power supply 28 (an example of a voltage application unit for the charging member) that applies a charging voltage to the charging member 14. The power supply 28 is electrically connected to the charging member 14.

Examples of charging components 14 in the charging device 15 include contact-type chargers using conductive charging rollers, charging brushes, charging films, charging rubber blades, charging tubes, etc. Other examples of charging components 14 include non-contact roller chargers, scorotron chargers or corotron chargers utilizing corona discharge, and other known chargers.

[Electrostatic image forming device]
The electrostatic image forming apparatus 16 forms an electrostatic image on the surface of a charged photoreceptor 12. Specifically, for example, the electrostatic image forming apparatus 16 irradiates the surface of the photoreceptor 12, which has been charged by a charging member 14, with light L modulated based on the image information of the image to be formed, thereby forming an electrostatic image on the photoreceptor 12 that corresponds to the image information.

Examples of electrostatic image forming apparatus 16 include optical systems with a light source that exposes an image-like object using light such as semiconductor laser light, LED light, or liquid crystal shutter light.

[Developing equipment]
The developing device 18 is located, for example, downstream of the photoreceptor 12 in the rotational direction from the irradiation position of light L by the electrostatic image forming device 16. The developing device 18 has a storage section for containing the developer. This storage section contains a developer containing toner. The toner is stored, for example, in a charged state within the developing device 18.

The developing apparatus 18 includes, for example, a developing member 18A that develops the electrostatic image formed on the surface of the photoreceptor 12 using a developer containing toner, and a power supply 32 that applies a developing voltage to the developing member 18A. The developing member 18A is electrically connected to, for example, the power supply 32.

The developing element 18A of the developing device 18 is selected according to the type of developer, but an example is a developing roll having a developing sleeve with a built-in magnet.

The developing device 18 (including the power supply 32) is electrically connected to, for example, a control device 36 provided in the image forming apparatus 10. The developing device 18 is driven and controlled by the control device 36 to apply a developing voltage to the developing member 18A. The developing member 18A, upon application of the developing voltage, becomes charged to a developing potential corresponding to the developing voltage. The developing member 18A, charged to the developing potential, then, for example, holds the developer contained within the developing device 18 on its surface and supplies the toner contained in the developer from within the developing device 18 to the surface of the photoreceptor 12. On the surface of the photoreceptor 12, where the toner is supplied, the formed electrostatic charge image is developed as a toner image.

[Transfer device]
The transfer device 31 is provided, for example, downstream of the developing member 18A in the rotational direction of the photoreceptor 12. The transfer device 31 includes, for example, a transfer member 20 that transfers the toner image formed on the surface of the photoreceptor 12 to the recording medium 30A, and a power supply 30 that applies a transfer voltage to the transfer member 20. The transfer member 20 is, for example, cylindrical and transports the recording medium 30A between itself and the photoreceptor 12. The transfer member 20 is electrically connected to, for example, the power supply 30.

Examples of transfer members 20 include contact-type transfer chargers using belts, rollers, films, rubber cleaning blades, etc., and non-contact type transfer chargers known to themselves, such as scorotron transfer chargers or corotron transfer chargers that utilize corona discharge.

The transfer apparatus 31 (including the power supply 30) is electrically connected to, for example, a control device 36 provided in the image forming apparatus 10. The control device 36 drives and controls the transfer apparatus to apply a transfer voltage to the transfer member 20. The transfer member 20, upon application of the transfer voltage, becomes charged to a transfer potential corresponding to the transfer voltage.

When a transfer voltage opposite in polarity to the toner constituting the toner image formed on the photoreceptor 12 is applied to the transfer member 20 from the power supply 30 of the transfer member 20, a transfer electric field of electric field strength is formed in the region where the photoreceptor 12 and the transfer member 20 face each other (see transfer region 32A in Figure 1), causing each toner constituting the toner image on the photoreceptor 12 to move from the photoreceptor 12 to the transfer member 20 side by electrostatic force.

The recording medium 30A is housed in a storage unit (not shown), and is transported along a transport path 34 by multiple transport members (not shown) to the transfer region 32A, which is the area where the photoreceptor 12 and the transfer member 20 face each other. In the example shown in Figure 1, it is transported in the direction of arrow B. Once the recording medium 30A reaches the transfer region 32A, the toner image on the photoreceptor 12 is transferred by a transfer electric field formed in that region, for example, when a transfer voltage is applied to the transfer member 20. That is, for example, the toner image is transferred onto the recording medium 30A by the movement of toner from the surface of the photoreceptor 12 to the recording medium 30A. The toner image on the photoreceptor 12 is then transferred onto the recording medium 30A by the transfer electric field.

[Cleaning device]
The cleaning device 22 is located downstream of the transfer device 31 in the rotational direction of the photoreceptor 12. The cleaning device 22 transfers the toner image to the recording medium 30A and cleans any residual toner and other substances adhering to the photoreceptor 12. Specifically, the cleaning device 22 cleans not only residual toner but also discharge products generated by the charging means, paper dust, and other adhering substances.

The cleaning device 22 has a cleaning blade 220, and removes deposits from the surface of the photoreceptor 12 by bringing the tip of the cleaning blade 220 into contact with the photoreceptor 12 in a direction opposite to the rotation direction of the photoreceptor 12.

The cleaning blade 220 is an elastic plate-like object.
The cleaning blade 220 is supported by a support member attached to the side opposite to the side that contacts the photoreceptor 12. This support member presses the cleaning blade 220 against the photoreceptor 12. Examples of support members include metal materials such as aluminum and stainless steel. There may also be an adhesive layer between the support member and the cleaning blade 220, made of an adhesive or the like, to bond the two together.
The cleaning device may include known components other than the cleaning blade 220 and the support member that supports it.

The cleaning blade 220 has a contact portion that comes into contact with the surface of the photoreceptor and cleans the surface of the photoreceptor (hereinafter also referred to as the "contact member") and a member that constitutes the base material layer (hereinafter also referred to as the "non-contact member").
The cleaning blade may have a two-layer structure consisting of a layer made of a contact member and a base material layer as a back layer on the back of the aforementioned layer, or it may have a three-layer or more structure. Alternatively, only the corners of the portion that contacts the photoreceptor may consist of a contact member, and the portion other than the contact member that does not contact the photoreceptor (i.e., the non-contact portion) may be the base material layer.

If the cleaning blade 220 has a laminated structure of two or more layers, the load applied to the contact point when it is in contact with the surface of the photoreceptor is suppressed from spreading across the entire cleaning blade 220, further suppressing chipping of the cleaning blade 220 even in low-temperature, low-humidity environments. Furthermore, it becomes easier to adjust the value of Δ(α23 edge - α23 base), described later, to a suitable range.

Figure 2 is a schematic diagram showing an example of the cleaning blade 220 in this embodiment.
As shown in Figure 2, the cleaning blade 3422B may have a two-layer configuration, comprising a first layer 3421B which is formed over the entire surface of the ventral side and includes a portion that contacts the photoreceptor 12 (contact corner), and a second layer 3422B which is formed on the back side of the first layer and is made of a different material from the contact member, serving as a base layer.

The cleaning blade 220 will be described in detail below, but the reference numerals will be omitted.

(Composition of contact members)
Hereafter, the components that make up the contact area will also be referred to as "contact members."
Examples of contact members include members containing rubber material.
The rubber material is not particularly limited, but examples include polyurethane rubber, polyimide rubber, silicone rubber, fluororubber, chloropyrene rubber, and butadiene rubber.
Among the upper components, a component containing polyurethane rubber is preferred as the contact component.

-Polyurethane rubber-
Polyurethane rubber is a polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component. The polyurethane rubber may also be a polyurethane rubber obtained by polymerizing a resin having functional groups that can react with the isocyanate groups of the polyisocyanate, in addition to the polyol component, as needed.

It is preferable that the polyurethane rubber has hard segments and soft segments. "Hard segments" and "soft segments" refer to segments in the polyurethane rubber material in which the material constituting the former is relatively harder than the material constituting the latter, and the material constituting the latter is relatively softer than the material constituting the former.
Materials constituting the hard segment (hard segment material) include low molecular weight polyol components and resins having functional groups that can react with the isocyanate groups of polyisocyanates. On the other hand, materials constituting the soft segment (soft segment material) include high molecular weight polyol components.

• Polyol components: Polyol components include high molecular weight polyols and low molecular weight polyols.

The high-molecular-weight polyol component is a polyol with a number-average molecular weight of 500 or more (preferably 500 to 5000). Examples of high-molecular-weight polyol components include well-known polyols such as polyester polyols obtained by dehydration condensation of low-molecular-weight polyols and dibasic acids, polycarbonate polyols obtained by the reaction of low-molecular-weight polyols and alkyl carbonates, polycaprolactone polyols, and polyether polyols. Examples of commercially available high-molecular-weight polyols include Praxel 205 and Praxel 240 manufactured by Daicel Corporation.

Here, the number-average molecular weight is the value measured by gel permeation chromatography (GPC). The same applies hereafter.

These polymeric polyols may be used individually or in combination of two or more types.

The polymerization ratio of the high-molecular-weight polyol component is preferably 30 mol% to 50 mol% relative to the total polymerization component of the polyurethane rubber, and more preferably 40 mol% to 50 mol%.

Low molecular weight polyol components are polyols with a molecular weight (number average molecular weight) of less than 500. Low molecular weight polyols function as chain length extenders and crosslinking agents.

Examples of low molecular weight polyol components include 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 1,20-eicosanediol. Among these, 1,4-butanediol is preferred as the low molecular weight polyol component.

Examples of low molecular weight polyol components include diols (bifunctional), triols (three-functional), or tetraols (four-functional), which are well known as chain length extenders and crosslinking agents.
These polyols may be used individually or in combination of two or more.

The polymerization ratio of the low molecular weight polyol component is preferably more than 50 mol% and less than or equal to 75 mol% relative to the total polymerization components of the polyurethane rubber, more preferably 52 mol% to 75 mol%, more preferably 55 mol% to 75 mol%, and even more preferably 55 mol% to 60 mol%.

Polyisocyanate components Examples of polyisocyanate components include 4,4'-diphenylmethane diisocyanate (MDI), 2,6-toluene diisocyanate (TDI), 1,6-hexane diisocyanate (HDI), 1,5-naphthalene diisocyanate (NDI), and 3,3-dimethylbiphenyl-4,4-diisocyanate (TODI).

As for the polyisocyanate component, 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), and hexamethylene diisocyanate (HDI) are more preferable.

These polyisocyanate components may be used individually or in combination of two or more.

The polymerization ratio of the polyisocyanate component is preferably 5 mol% to 25 mol%, and more preferably 10 mol% to 20 mol%, relative to the total polymerization components of the polyurethane rubber.

Resins having functional groups that can react with isocyanate groups Resins having functional groups that can react with isocyanate groups (hereinafter referred to as "functional group-containing resins") are preferably flexible resins, and more preferably aliphatic resins having a linear structure from the viewpoint of flexibility. Specific examples of functional group-containing resins include acrylic resins containing two or more hydroxyl groups, polybutadiene resins containing two or more hydroxyl groups, and epoxy resins containing two or more epoxy groups.

Examples of commercially available acrylic resins containing two or more hydroxyl groups include Actflow (grades: UMB-2005B, UMB-2005P, UMB-2005, UME-2005, etc.) manufactured by Soken Chemical Co., Ltd.

Examples of commercially available polybutadiene resins containing two or more hydroxyl groups include R-45HT, manufactured by Idemitsu Kosan Co., Ltd.

The epoxy resin having two or more epoxy groups is preferably one that is more flexible and tough than conventional epoxy resins, rather than having the hard and brittle properties of conventional epoxy resins. For example, in terms of molecular structure, the epoxy resin is preferably one that has a structure (flexible skeleton) in its main chain that allows for high mobility of the main chain. Examples of flexible skeletons include alkylene skeletons, cycloalkane skeletons, and polyoxyalkylene skeletons, with polyoxyalkylene skeletons being particularly preferred.
Furthermore, in terms of physical properties, epoxy resins with a lower viscosity relative to their molecular weight are preferred compared to conventional epoxy resins. Specifically, it is desirable that the weight-average molecular weight is within the range of 900 ± 100, and the viscosity at 25°C is within the range of 15,000 ± 5,000 mPa·s, and more preferably within the range of 15,000 ± 3,000 mPa·s. Examples of commercially available epoxy resins having these characteristics include DIC's EPLICON EXA-4850-150.

The polymerization ratio of the functional group-containing resin should be within a range that does not impair the effectiveness of the cleaning blade according to this embodiment.

The weight-average molecular weight of the rubber material constituting the contact member is preferably 1000 to 4000, and more preferably 1500 to 3500. The above weight-average molecular weight is the value measured by gel permeation chromatography (GPC).

• Method for manufacturing polyurethane rubber Polyurethane rubber can be manufactured using general polyurethane manufacturing methods such as the prepolymer method or the one-shot method. The prepolymer method is suitable for this embodiment because it yields polyurethane with excellent abrasion resistance and chipping properties, but the method is not limited to this embodiment.
The cleaning blade is manufactured by forming the cleaning blade composition prepared by the above method into a sheet using, for example, centrifugal molding or extrusion molding, and then cutting it.

(Composition of non-contact components)
The components that make up the base layer will also be referred to as "non-contact components" below.
The materials constituting the contact member and the materials constituting the non-contact member may have the same or different component compositions, but it is preferable that they be different.

For example, if the types and proportions of each material differ, the materials constituting the contact member and the materials of the base layer are considered to have different component compositions. For example, if polyurethane rubber has hard segments and soft segments, the component compositions are also considered to be different if the mixing ratios of the two differ.
For example, even if both materials are polyurethane, thermoplastic plastics and thermoplastic elastomers are considered to have different component compositions.

The following describes the composition of the non-contact member (hereinafter also referred to as the "non-contact member") when the cleaning blade is composed of different materials for the contact member and the member constituting the base layer.

The non-contact member can be any known material without particular limitation, as long as it has the function of supporting the contact member. Specifically, examples of materials used for the non-contact member include polyurethane rubber, silicone rubber, fluororubber, proloprene rubber, and butadiene rubber. Among these, polyurethane rubber is preferred. Examples of polyurethane rubber include ester-based polyurethane and ether-based polyurethane, with ester-based polyurethane being particularly desirable.

(Method of manufacturing a cleaning blade)
While known methods can be applied to the manufacturing method of a cleaning blade, for example, a cleaning blade with two or more layers is manufactured by bonding together a first layer as a contact member and a second layer as a base layer (non-contact member) (or multiple layers in the case of a three or more-layer structure). Suitable bonding methods include double-sided tape and various adhesives. Alternatively, multiple layers may be bonded by pouring the materials for each layer into the mold with a time difference during molding, thereby bonding the materials together without the need for an adhesive layer.

(Characteristics of the cleaning blade)
In the image forming apparatus according to this embodiment, the relationship between the content X (mass%) of resin particles relative to the toner particles and the 100% modulus α23 edge at 23°C of the contact portion of the cleaning blade is as follows:
Satisfying 0.12 ≤ X/α23 edge ≤ 7.5,
It is more preferable that 0.25 ≤ X/α23 edge ≤ 4.3 is satisfied.
By satisfying the above relationship 0.12 ≤ X/α23 edge ≤ 7.5, even in low-temperature, low-humidity environments where the toner's viscoelasticity is low, the external additive does not become excessively detached, and the removal efficiency of the external additive is more easily maintained. As a result, the occurrence of chipping at the tip of the cleaning blade is also further suppressed. Furthermore, even in high-temperature, high-humidity environments where the toner's viscoelasticity is high, the adhesion force of the toner to the photoreceptor surface does not become excessively high, and the removal efficiency of deposits on the photoreceptor is less likely to decrease. As a result, even when repeatedly forming images, it is thought that streaky image defects caused by toner particles slipping through from the cleaning blade are further suppressed.

The 100% modulus α23 edge of the contact portion of the cleaning blade at 23°C is preferably 4 MPa to 18 MPa, and more preferably 6 to 16.
When the α23 edge of the cleaning blade's contact area is within the above range, it becomes easier to adjust the aforementioned X/α23 edge to a suitable range. As a result, both chipping of the cleaning blade tip in low-temperature, low-humidity environments and streaky image defects in high-temperature, high-humidity environments tend to be suppressed.

It is preferable that the 100% modulus α23base of the base layer of the cleaning blade at 23°C is lower than the 100% modulus α23edge of the contact portion at 23°C.

If the 100% modulus α23base of the cleaning blade's substrate layer at 23°C is lower than the 100% modulus α23edge of the contact portion at 23°C, the stress on the cleaning blade when it comes into contact with the photoreceptor surface is easily suppressed, making it easier to adjust the aforementioned X/α23edge to a suitable range. Therefore, both chipping of the cleaning blade tip in low-temperature, low-humidity environments and streaky image defects in high-temperature, high-humidity environments tend to be suppressed.

- Characteristics during cleaning blade operation In the image forming apparatus according to this embodiment, the relationship between the content X (mass%) of resin particles relative to the toner particles and the 100% modulus α30 edge of the contact portion of the cleaning blade at 30°C is
It is preferable that 0.14 ≤ X/α30 edge ≤ 9.8 is satisfied.
It is more preferable that 0.15 ≤ X/α30 edge ≤ 7.5 is satisfied.

Generally, the ambient temperature during cleaning blade operation in an image forming apparatus, i.e., the operating environment temperature, is approximately 30°C. Therefore, if the X/α30 edge relationship at 30°C for the cleaning blade contact area satisfies the above range, then, even in regions where the toner's viscoelasticity is low during cleaning blade operation in low-temperature, low-humidity environments, the external additive will not be excessively released, and the removal efficiency of the external additive will be more easily maintained. As a result, the occurrence of chipping at the tip of the cleaning blade will be further suppressed. Furthermore, even in regions where the toner's viscoelasticity is high during cleaning blade operation in high-temperature, high-humidity environments, the adhesion of the toner to the photoreceptor surface will not become excessively high, and the removal efficiency of deposits on the photoreceptor will not decrease as easily. As a result, even when repeatedly forming images, it is believed that streaky image defects caused by toner particles slipping through from the cleaning blade will be further suppressed.

The 100% modulus α30 edge of the contact portion of the cleaning blade at 30°C is preferably 3 MPa to 16 MPa, and more preferably 4 MPa to 14 MPa.
When the α30 edge of the cleaning blade's contact area is within the above range, it becomes easier to adjust the aforementioned X/α30 edge to a suitable range. As a result, both chipping of the cleaning blade tip in low-temperature, low-humidity environments and streaky image defects in high-temperature, high-humidity environments tend to be suppressed.

Preferably, the 100% modulus α30 base of the base layer of the cleaning blade at 30°C is lower than the 100% modulus α30 edge of the contact portion at 30°C.
If the 100% modulus α30 base of the cleaning blade's substrate layer at 30°C is lower than the 100% modulus α30 edge of the contact area at 30°C, the stress on the cleaning blade when it comes into contact with the surface of the photoreceptor during operation is suppressed, making it easier to adjust the aforementioned X/α30 edge to a suitable range. As a result, both chipping of the cleaning blade tip in low-temperature, low-humidity environments and streaky image defects in high-temperature, high-humidity environments tend to be suppressed.

The methods for adjusting the values of X/α23edge, α23edge, the height relationship between α23edge and α23base, and X/α30edge, α30edge, and the height relationship between α30edge and α30base are not particularly limited. Examples include adjusting the resin particle content in the toner particles; selecting the type and amount of each polymerization component of the polyurethane rubber, as well as the manufacturing conditions, if the contact member of the cleaning blade contains polyurethane rubber; and adjusting the modulus by adjusting the isocyanate part ratio in the urethane rubber material.

The 100% modulus measurement at each temperature is performed as follows.
In accordance with JIS-K6251, a dumbbell-shaped No. 3 test specimen was used at each temperature, and measurements were taken at a tensile speed of 500 mm/min. The stress at 100% strain was then determined. The measuring device used was a Strograph AE elastomer manufactured by Toyo Seiki Co., Ltd.

[Static eliminator]
The static elimination device 24 is, for example, located downstream of the cleaning device 22 in the rotational direction of the photoreceptor 12. After transferring the toner image, the static elimination device 24 exposes the surface of the photoreceptor 12 to remove static electricity. Specifically, for example, the static elimination device 24 is electrically connected to a control device 36 provided in the image forming apparatus 10, and is driven and controlled by the control device 36 to expose the entire surface of the photoreceptor 12 (specifically, for example, the entire image forming area) to remove static electricity.

Examples of static elimination devices 24 include devices having light sources such as a tungsten lamp that emits white light or a light-emitting diode (LED) that emits red light.

[Fusing device]
The fixing device 26 is provided, for example, downstream of the transfer area 32A in the transport direction of the transport path 34 of the recording medium 30A. The fixing device 26 has a fixing member 26A and a pressurizing member 26B positioned in contact with the fixing member 26A, and fixes the toner image transferred onto the recording medium 30A at the contact portion between the fixing member 26A and the pressurizing member 26B. Specifically, for example, the fixing device 26 is electrically connected to a control device 36 provided in the image forming apparatus 10, and is driven and controlled by the control device 36 to fix the toner image transferred onto the recording medium 30A to the recording medium 30A by heat and pressure.

Examples of the fixing device 26 include known fixing devices such as a hot roller fixing device and an oven fixing device.
Specifically, for example, the fixing device 26 may be a well-known fixing device comprising a fixing roll or fixing belt as a fixing member 26A and a pressure roll or pressure belt as a pressure member 26B.

Here, the recording medium 30A, which has been transported along the transport path 34 and has the toner image transferred by passing through the area where the photoreceptor 12 and the transfer member 20 face each other (transfer area 32A), is further transported along the transport path 34 by a transport member (not shown) to the installation position of the fixing device 26, where the toner image on the recording medium 30A is fixed.

The recording medium 30A, on which the image has been formed by fixing the toner image, is discharged to the outside of the image forming apparatus 10 by multiple transport members (not shown in the figure). The photoreceptor 12 is then discharged by the static elimination device 24 and subsequently recharged to a charging potential by the charging device 15.

[Operation of the image forming apparatus]
An example of the operation of the image forming apparatus 10 according to this embodiment will be described. Note that various operations of the image forming apparatus 10 are performed by a control program executed in the control device 36.

The image forming operation of the image forming apparatus 10 will be described.
First, the surface of the photoreceptor 12 is charged by the charging device 15. The electrostatic image forming device 16 exposes the charged surface of the photoreceptor 12 based on image information. This forms an electrostatic image on the photoreceptor 12 corresponding to the image information. In the developing device 18, the electrostatic image formed on the surface of the photoreceptor 12 is developed with a developer containing toner. This forms a toner image on the surface of the photoreceptor 12.
In the transfer device 31, the toner image formed on the surface of the photoreceptor 12 is transferred to the recording medium 30A. The toner image transferred to the recording medium 30A is fixed by the fuser device 26.
Meanwhile, the surface of the photoreceptor 12 after the toner image has been transferred is cleaned by the cleaning blade 220 in the cleaning device 22, and then static electricity is removed by the static elimination device 24.

[toner]
The toner according to this embodiment comprises toner particles including a binder resin and resin particles, and an external additive.

(Toner particles)
The toner particles include at least a binder resin and resin particles.
Toner particles are composed of, as necessary, colorants, release agents, and other additives. Hereinafter, resin particles added to toner particles will be referred to as "added resin particles" to distinguish them from the resin particles that serve as the binder resin used in the manufacture of toner particles.

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

The binder resin may contain an amorphous resin. The binder resin may also contain a crystalline resin together with the amorphous resin. However, the mass ratio of amorphous resin to crystalline resin (crystalline resin/amorphous resin) is preferably 2/98 or more and 50/50 or less, and more preferably 4/96 or more and 30/70 or less.
Here, amorphous resin refers to a material that, in thermal analysis measurements using differential scanning calorimetry (DSC), exhibits only a stepwise endothermic change rather than a clear endothermic peak, is a solid at room temperature, and undergoes thermoplasticization at temperatures above its glass transition temperature.
On the other hand, crystalline resins are those that exhibit a clear endothermic peak in differential scanning calorimetry (DSC), rather than a stepwise change in endothermic heat.
Specifically, for example, amorphous resins refer to resins whose full width at half maximum (FWHM) exceeds 10°C, or resins in which no clear endothermic peak is observed. Crystalline resins refer to resins in which the FWHM of the endothermic peak measured at a heating rate of 10°C/min is within 10°C.

This section will explain amorphous resins.
Examples of amorphous resins include known amorphous resins such as amorphous polyester resin, amorphous vinyl resin (e.g., styrene-acrylic resin), epoxy resin, polycarbonate resin, and polyurethane resin. Among these, amorphous polyester resin and amorphous vinyl resin (particularly styrene-acrylic resin) are preferred, and amorphous polyester resin is more preferred.

Amorphous polyester resins: Examples of amorphous polyester resins include condensation polymers of polycarboxylic acids and polyhydric alcohols. Commercially available amorphous polyester resins may be used, or synthesized ones may be used.

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, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids.
Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a crosslinked or branched structure. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms).
Polycarboxylic acids may be used individually or in combination of two or more.

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 for the polyhydric alcohol, a trihydric or higher polyhydric alcohol with a cross-linked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol.
Polyhydric alcohols may be used individually or in combination of two or more types.

The glass transition temperature (Tg) of amorphous polyester resin is preferably 50°C to 80°C, and more preferably 50°C to 65°C.
The glass transition temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, from the "extracorporeal glass transition onset temperature" described in JIS K 7121-1987 "Method for Measuring Transition Temperatures of Plastics".

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

Amorphous polyester resins can be obtained by well-known manufacturing methods. Specifically, for example, they can be obtained by a method in which the polymerization temperature is set to 180°C or higher and 230°C or lower, and the reaction system is subjected to reduced pressure as needed, while removing water and alcohol generated during condensation.
If the monomers of the raw materials do not dissolve or become miscible at the reaction temperature, a high-boiling point solvent may be added as a solubilizer to dissolve them. In this case, the polycondensation reaction should be carried out while distilling off the solubilizer. If there are monomers with poor miscibility, it is advisable to condense the poorly miscible monomers with the acid or alcohol to be polycondensed with them beforehand, and then polycondense them together with the main component.

This section will explain crystalline resins.
Examples of crystalline resins 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 of the toner and low-temperature fixability.

Crystalline polyester resins include, for example, polycondensates of polycarboxylic acids and polyhydric alcohols. Commercially available crystalline polyester resins may be used, or synthesized resins may be used.
Here, in order to easily form a crystalline structure, polycondensates using polymerizable monomers having linear aliphatic structures are preferred over polymerizable monomers having aromatic structures.

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., phthalic acid, isophthalic acid, terephthalic acid, dibasic acids such as naphthalene-2,6-dicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms).
Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a crosslinked or branched structure. Examples of trivalent carboxylic acids include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalentricarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms).
In addition to these dicarboxylic acids, polycarboxylic acids with sulfonic acid groups and dicarboxylic acids with ethylenic double bonds may also be used in combination.
Polycarboxylic acids may be used individually or in combination of two or more.

Examples of polyhydric alcohols include aliphatic diols (for example, linear 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-eicosandecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols.
Polyhydric alcohols may be used in combination with diols, including trihydric or higher alcohols that have a cross-linked or branched structure. Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.
Polyhydric alcohols may be used individually or in combination of two or more types.

Here, the polyhydric alcohol preferably contains 80 mol% or more of aliphatic diols, and more preferably 90 mol% or more.

The melting temperature of the crystalline polyester resin is preferably 50°C to 100°C, more preferably 55°C to 90°C, and even more preferably 60°C to 85°C.
The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K7121-1987 "Method for determining the transition temperature of plastics".

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

Crystalline polyester resins can be obtained, for example, by well-known manufacturing methods, similar to amorphous polyesters.

The binder resin content is preferably 40% to 95% by mass, more preferably 50% to 90% by mass, and even more preferably 60% to 85% by mass, relative to the total toner particles.

-Internal resin particles-
The internally added resin particles are preferably resin particles in which the storage modulus G' in the range of 23°C to 80°C, measured in dynamic viscoelasticity measurements at a temperature increase of 2°C/min, is 1 × ^10⁵ Pa or more and 5 × ^10⁷ Pa or less.
The storage modulus G' of the internally added resin particles in the range of 23°C to 80°C is preferably 1 × ^10⁵ Pa to 2 × ^10⁷ Pa, and more preferably 1 × ^10⁵ Pa to 1 × ^10⁷ Pa.

Internally added resin particles whose storage modulus G' in the range of 23°C to 80°C are within the above range are particles with high elasticity even in the range of 23°C to 80°C. Therefore, by incorporating internally added resin particles with a storage modulus G' within the above range into the toner particles, the toner is more susceptible to the elasticity of the internally added resin particles even when fixing the toner at low temperatures. As a result, the viscoelasticity of the toner particles is more easily maintained in both high-temperature, high-humidity and low-temperature, low-humidity environments, and both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments are more suppressed.

The storage modulus G' of the internally added resin particles is measured as follows:
By applying pressure to the internal resin particles to be measured, a disc-shaped sample with a thickness of 2 mm and a diameter of 8 mm is prepared and used as the measurement sample. When measuring internal resin particles contained in toner particles, the internal resin particles are extracted from the toner particles before preparing the measurement sample. One method for extracting internal resin particles from toner particles is to immerse the toner particles in a solvent that dissolves the binder resin but not the internal resin particles, thereby dissolving the binder resin in the solvent and extracting the internal resin particles.
Then, the obtained disc-shaped sample for measurement is sandwiched between parallel plates with a diameter of 8 mm, and dynamic viscoelasticity measurements are performed under the following conditions, with a strain of 0.1 to 100% and the measurement temperature raised from 23°C to 80°C at a rate of 2°C/min. The storage modulus G' is determined from the storage modulus and loss modulus curves obtained from the measurement.
-Measurement conditions-
Measuring device: Rheometer ARES-G2 (manufactured by T.A. Instruments Co., Ltd.)
Gap: Adjusted to 3mm Frequency: 1Hz

The internally added resin particles are preferably cross-linked resin particles.
Here, "crosslinked resin particles" refers to resin particles that have a crosslinking structure between specific atoms in the polymer structure contained within the resin particles.

By using cross-linked resin particles as the internal additive, the storage modulus G' in the range of 23°C to 80°C is more likely to fall within this range. Therefore, by incorporating internal additive resin particles with a storage modulus G' within this range into the toner particles, the toner is more susceptible to the elasticity of the internal additive resin particles even when fixing the toner at low temperatures. As a result, the viscoelasticity of the toner particles is more easily maintained in both high-temperature, high-humidity and low-temperature, low-humidity environments, further suppressing both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments.

Examples of crosslinked resin particles include those crosslinked by ionic bonds (ionic crosslinked resin particles) and those crosslinked by covalent bonds (covalently crosslinked resin particles). Among these, crosslinked resin particles crosslinked by covalent bonds are preferred.

Examples of resins used in crosslinked resin particles include polyolefin resins (polyethylene, polypropylene, etc.), styrene resins (polystyrene, α-polymethylstyrene, etc.), (meth)acrylic resins (polymethyl methacrylate, polyacrylonitrile, etc.), epoxy resins, polyurethane resins, polyurea resins, polyamide resins, polycarbonate resins, polyether resins, polyester resins, and copolymers thereof. These resins may be used individually or in mixtures of two or more types, as needed.

Among the above resins, styrene (meth)acrylic resin is preferred as the resin used for crosslinked resin particles.
In other words, styrene (meth)acrylic resin particles are preferred as the crosslinked resin particles.

Because the cross-linked resin particles are styrene (meth)acrylic resin particles, the internally added resin particles are more likely to have a storage modulus G' within the range of 23°C to 80°C. Therefore, by including internally added resin particles with a storage modulus G' within the above range in the toner particles, the toner is more susceptible to the elasticity of the internally added resin particles even when fixing the toner at low temperatures. As a result, the viscoelasticity of the toner particles is more easily maintained in both high-temperature, high-humidity and low-temperature, low-humidity environments, and both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments are more suppressed.

Examples of styrene (meth)acrylic resins include resins obtained by polymerizing the following styrene monomers and (meth)acrylic acid monomers by radical polymerization.

Examples of styrene monomers include styrene, α-methylstyrene, vinylnaphthalene, alkyl-substituted styrenes having alkyl chains such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene, halogen-substituted styrenes such as 2-chlorostyrene, 3-chlorostyrene, and 4-chlorostyrene, and fluorine-substituted styrenes such as 4-fluorostyrene and 2,5-difluorostyrene. Among these, styrene and α-methylstyrene are preferred.

Examples of (meth)acrylic acid monomers include (meth)acrylic acid, n-methyl (meth)acrylate, n-ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isopentyl (meth)acrylate, amyl (meth)acrylate, (meth)acrylate Examples include neopentyl acrylate, isohexyl methacrylate, isoheptyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, biphenyl methacrylate, diphenylethyl methacrylate, t-butylphenyl methacrylate, terphenyl methacrylate, cyclohexyl methacrylate, t-butylcyclohexyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, methoxyethyl methacrylate, 2-hydroxyethyl methacrylate, β-carboxyethyl methacrylate, acrylonitrile, and methacrylamide. Among these, n-butyl methacrylate and β-carboxyethyl methacrylate are preferred.

In crosslinked resin particles, crosslinking agents for crosslinking the resin include, for example, aromatic polyvinyl compounds such as divinylbenzene and divinylnaphthalene; polyvinyl esters of aromatic polycarboxylic acids such as divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesicate, trivinyl trimesicate, divinyl naphthalenedicarboxylate, and divinyl biphenylcarboxylate; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridinedicarboxylate; vinyl esters of unsaturated heterocyclic compound carboxylic acids such as vinyl pyromutinate, vinyl furanate, pyrrole-2-carboxylate, and vinyl thiophenecarboxylate; and nitrate dimethacrylates such as butanediol diacrylate, butanediol dimethacrylate, hexanediol diacrylate, octanediol dimethacrylate, decanediol diacrylate, and dodecanediol dimethacrylate. Examples include (meth)acrylic acid esters of chain polyhydric alcohols; (meth)acrylic acid esters of branched and substituted polyhydric alcohols such as neopentyl glycol dimethacrylate and 2-hydroxy, 1,3-diacroxypropane; polyvinyl esters of polycarboxylic acids such as polyethylene glycol di(meth)acrylate, polypropylene polyethylene glycol di(meth)acrylates, divinyl succinate, divinyl fumarate, vinyl maleate, divinyl maleate, divinyl diglycolate, vinyl itaconate, divinyl itaconate, divinyl acetonedicarboxylic acid, divinyl glutarate, divinyl 3,3'-thiodipropionate, divinyl trans-aconitate, trivinyl trans-aconitate, divinyl adipic acid, divinyl pimephosphate, divinyl suberate, divinyl azelaate, divinyl sebacate, divinyl dodecanediate, and divinyl brassylate. The crosslinking agent may be used alone or in combination of two or more types.

Furthermore, if the internally added resin particles are a polymer of a composition for forming internally added resin particles containing a styrene monomer, a (meth)acrylic acid monomer, and a crosslinking agent, the viscoelasticity of the internally added resin particles may be controlled by adjusting the amount of crosslinking agent contained in the composition. For example, increasing the amount of crosslinking agent in the composition makes it easier to obtain internally added resin particles with a high storage modulus G'. The crosslinking agent content in the composition for forming internally added resin particles is preferably 0.3 parts by mass or more and 5.0 parts by mass or less, more preferably 0.5 parts by mass or more and 2.5 parts by mass or less, and even more preferably 1.0 part by mass or more and 2.0 parts by mass or less, per 100 parts by mass of the total of the styrene monomer, (meth)acrylic acid monomer, and crosslinking agent.

The number-average particle size of the internally added resin particles is preferably 60 nm to 300 nm, more preferably 100 nm to 200 nm, and even more preferably 130 nm to 170 nm.
When the number-average particle size of the internally added resin particles is 60 nm or larger, the toner particles are more susceptible to the effects of the high elasticity of the internally added resin particles compared to when the particle size is less than 60 nm. Furthermore, when the number-average particle size of the internally added resin particles is 300 nm or smaller, the internally added resin particles are more easily dispersed with higher uniformity within the toner particles compared to when the particle size exceeds 300 nm. As a result, the viscoelasticity of the toner particles is more easily maintained in both high-temperature, high-humidity and low-temperature, low-humidity environments, and both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments are more suppressed.

The number-average particle size of the internally added resin particles is a value measured using a transmission electron microscope (TEM).
As a transmission electron microscope, for example, the JEM-1010 manufactured by JEOL Datum Ltd. can be used.
The following describes in detail the method for measuring the number-average particle size of internally added resin particles.
The toner particles are cut into pieces approximately 0.3 μm thick using a microtome. A 4500x magnification photograph of the cross-section of the toner particles is taken using a transmission electron microscope. For 1000 internal resin particles dispersed within the toner particles, the equivalent diameter of each circle is calculated from the individual cross-sectional area, and the arithmetic mean of these values is used as the number-average particle size.

The content C of the internally added resin particles is preferably 2% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 25% by mass or less, and even more preferably 8% by mass or more and 20% by mass or less, relative to the total toner particles.
When the content C of the internally added resin particles is 2% by mass or more, the toner particles are easily affected by the elasticity of the internally added resin particles, resulting in an appropriate hardness. On the other hand, when the content C of the internally added resin particles is 30% by mass or less, the internally added resin particles tend to disperse more uniformly within the toner particles.
Therefore, the viscoelasticity of the toner particles is more easily maintained in both high-temperature, high-humidity and low-temperature, low-humidity environments, and the X/α23 edge range is more easily adjusted to suit the conditions. As a result, both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments are more suppressed.

-Coloring agent-
Examples of colorants include carbon black, chrome yellow, Hansa yellow, benzidine yellow, surene 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, risole red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, and ultramarine. Examples include various pigments such as phosphorus blue, chalcioyl blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, as well as various dyes such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole.
Colorants may be used individually or in combination of two or more types.

The coloring agent may be a surface-treated coloring agent as needed, and may be used in combination with a dispersant. Furthermore, multiple types of coloring agents may be used in combination.

The colorant content is preferably 1% to 30% by mass, and more preferably 3% to 15% by mass, relative to the total toner particles.

-Release agent-
Examples of release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral/petroleum-based waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. However, release agents are not limited to these.

The melting temperature of the release agent is preferably 50°C to 110°C, and more preferably 60°C to 100°C.
The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K 7121-1987 "Method for determining the transition temperature of plastics".

The release agent content is preferably 1% to 20% by mass, and more preferably 5% to 15% by mass, relative to the total toner particles.

- Other additives -
Other additives include well-known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are included in the toner particles as internal additives.

- Relationship of composition within toner particles -
Difference (SP value (S) - SP value (R))
The difference between the solubility parameter SP value (S) of the internally added resin particles and the solubility parameter SP value (R) of the binder resin (SP value (S) - SP value (R)) is preferably -0.32 or more and -0.12 or less.

When the difference (SP value (S) - SP value (R)) is within the above range, the internally added resin particles are more easily dispersed in a nearly uniform state within the toner particles compared to when it is smaller than the above range.
Furthermore, when the difference (SP value (S) - SP value (R)) is within the above range, compared to when it is greater than the above range, the increase in the overall melt viscosity of the toner due to excessive mixing and compatibility of the internally added resin particles and the binder resin during toner melting is suppressed.
If the binder resin is a mixed resin, the solubility parameter of the resin with the highest content ratio in the binder resin is defined as the SP value (R).

The difference (SP value (S) - SP value (R)) is more preferably between -0.32 and -0.12, and even more preferably between -0.29 and -0.18.

The solubility parameter SP value (S) of the internally added resin particles is preferably 9.00 or higher and 9.15 or lower, more preferably 9.03 or higher and 9.12 or lower, and even more preferably 9.06 or higher and 9.10 or lower.

Here, the solubility parameter SP value (S) of the internally added resin particles and the solubility parameter SP value (R) of the binder resin (unit: (cal/ ^cm³ ) ^1/2 ) are calculated using the Okitsu method. The Okitsu method is described in detail in "Journal of the Adhesion Society of Japan, Vol. 29, No. 5 (1993)".

- Viscoelasticity of the component excluding the internally added resin particles (excluded component) It is preferable that the storage modulus G' of the component excluding the internally added resin particles from the toner particles is 1 × ^10⁸ Pa or more in the range of 23°C to 50°C, and that the temperature at which the storage modulus G' falls below 1 × ^10⁵ Pa is 65°C to 90°C.
Hereinafter, the components obtained by removing the internally added resin particles from the toner particles will also be referred to as "excluded components," and the temperature at which the storage modulus G' reaches less than 1 × ^10⁵ Pa will also be referred to as the "specific modulus attainment temperature." Excluded components whose storage modulus G' satisfies the above conditions have a high modulus at low temperatures and a low modulus at temperatures between 65°C and 90°C. Here, when the storage modulus G' of the excluded components satisfies the above conditions, the viscoelasticity of the toner particles is more easily maintained in both ^high -temperature, high-humidity and low-temperature, low-humidity environments compared to when the temperature at which the storage modulus G' reaches less than 1 × 10⁵ Pa exceeds 90°C. Therefore, the viscoelasticity of the toner particles is more easily maintained in both high-temperature, high-humidity and low-temperature, low-humidity environments, and both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments are more suppressed.

The storage modulus G' of the excluded component at temperatures between 23°C and 50°C is preferably 1 × ^10⁸ Pa or higher, more preferably 1 × ^10⁸ Pa or higher and 1 × ^10⁹ Pa or lower, and even more preferably 2 × ^10⁸ Pa or higher and 6 × ^10⁸ Pa or lower.

Furthermore, the temperature at which the elastic modulus is reached in the excluded components is preferably 65°C to 90°C, more preferably 68°C to 80°C, and even more preferably 70°C to 75°C.

The storage modulus G' of the excluded component is determined as follows.
Specifically, the process involves first removing the internally added resin particles from the toner particles to extract only the excluded components, and then molding these excluded components into tablets at 25°C using a press molding machine to prepare a sample for measurement. Methods for removing the internally added resin particles from the toner particles to extract only the excluded components include, for example, immersing the toner particles in a solvent that dissolves the binder resin but not the internally added resin particles, and then extracting the excluded components.
The obtained sample for measurement is then sandwiched between 8 mm diameter parallel plates, and dynamic viscoelasticity measurements are performed under the following conditions, with a strain of 0.1 to 100% and the measurement temperature increased from 30°C to 150°C at a rate of 2°C/min. The storage modulus G' is determined from the storage modulus and loss modulus curves obtained from the measurement.
-Measurement conditions-
Measuring device: Rheometer ARES-G2 (manufactured by T.A. Instruments Co., Ltd.)
Measurement jig: 8mm parallel plate; Gap: Adjusted to 3mm; Frequency: 1Hz

- Characteristics of toner particles, etc. -
The toner particles may be single-layer toner particles, or they may be toner particles with a so-called core-shell structure, consisting of a core (core particle) and a coating layer (shell layer) that covers the core.
Here, the core-shell structure of the toner particles preferably comprises, for example, a core portion comprising a binder resin, internal resin particles, and other additives such as colorants and release agents as needed, and a coating layer comprising a binder resin and internal resin particles.

When toner particles have a core-shell structure, it is preferable that both the core particle and the shell layer contain internally added resin particles. By containing internally added resin particles in both the core particle and the shell layer, the difference in gloss levels is further reduced because the internally added resin particles are present in both the surface and central regions of the toner particle.

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

The average particle size and particle size distribution indices of the toner particles are measured using the Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using ISOTON-II (manufactured by Beckman Coulter).
For measurement, 0.5 mg to 50 mg of the sample to be measured is added to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. This is then added to 100 ml to 150 ml of electrolyte.
The electrolyte containing the suspended sample is dispersed in an ultrasonic disperser for 1 minute. The particle size distribution of particles with a diameter of 2 μm to 60 μm is then measured using a Coulter Multisizer II with an aperture diameter of 100 μm. The number of particles sampled is 50,000.
Based on the measured particle size distribution, a cumulative distribution of volume and number is drawn for each divided particle size range (channel) from the smallest diameter side. The particle size at which the cumulative total reaches 16% is defined as the volume particle size D16v and the number particle size D16p, the particle size at which the cumulative total reaches 50% is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size at which the cumulative total reaches 84% is defined as the volume particle size D84v and the number particle size D84p.
Using these, the volume particle size distribution index (GSDv) is calculated as (D84v/D16v) ^1/2 , and the number particle size distribution index (GSDp) is calculated as (D84p/D16p) ^1/2 .

The average circularity of the toner particles is preferably 0.94 to 1.00, and more preferably 0.95 to 0.98.

The average circularity of toner particles is determined by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle with the same projected area as the particle image) / (perimeter of the particle projection image)]. Specifically, it is a value measured by the following method.
First, the toner particles to be measured are collected by suction, a flattened flow is formed, and a strobe flash is instantaneously activated to capture a still image of the particles. This particle image is then analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation). The number of samples used to determine the average circularity is 3500.
If 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.

(External additive)
Examples of external additives include inorganic particles. Examples of such inorganic particles include _SiO₂ , _TiO₂ , _Al₂O₃ , CuO, ZnO, _SnO₂ , _CeO₂ , _Fe₂O₃ , MgO, _BaO , _CaO , _K₂O , _Na₂O , _ZrO₂ , CaO・_SiO₂ , _K₂O・( _TiO₂ )n, _Al₂O₃・_2SiO₂ , _CaCO₃ , _MgCO₃ , _BaSO₄ , _{MgSO₄ ,} etc.

The surface of the inorganic particles used as an external additive should preferably be hydrophobic. Hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic agent. The hydrophobic agent is not particularly limited, but examples include silane-based coupling agents, silicone oil, titanate-based coupling agents, and aluminum-based coupling agents. These may be used individually or in combination of two or more.
The amount of hydrophobic treatment agent is typically, for example, 1 to 10 parts by mass per 100 parts by mass of inorganic particles.

Examples of external additives include resin particles (such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), and cleaning activators (for example, metal salts of higher fatty acids represented by zinc stearate, and fluorine-based high molecular weight particles).

In this case, it is preferable that the toner contains silica particles as an external additive. In particular, it is preferable that the toner contains titanium dioxide particles together with the silica particles as an external additive.
Silica particles have a property that makes them easily detached from toner particles, and this property is especially pronounced when used in combination with titanium dioxide particles.
Therefore, the external additive is more easily absorbed into the contact area between the cleaning blade and the photoreceptor, improving cleaning performance while suppressing wear on the cleaning blade and scratching of the electrophotographic photoreceptor. As a result, both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments are suppressed.

The amount of external additive added is preferably 0.01% by mass or more and 5% by mass or less relative to the toner particles, and more preferably 0.01% by mass or more and 2.0% by mass or less.
When the amount of external additive is 0.01% by mass or more, it is easier to suppress the excessive amount of free external additive, and both filming in high temperature and high humidity environments are further suppressed. On the other hand, when the amount of external additive is 5% by mass or less, it is easier to suppress the excessive amount of free external additive, and the occurrence of chipping of the cleaning blade tip due to some of the excessively free external additive passing through the cleaning blade is further suppressed.

(Toner characteristics)
- Viscoelasticity of toner -
In the dynamic viscoelasticity measurement of the toner according to this embodiment, when the loss tangent tanδ at a temperature of 90°C and a strain of 1% is D1(90), the loss tangent tanδ at a temperature of 90°C and a strain of 50% is D50(90), the loss tangent tanδ at a temperature of 150°C and a strain of 1% is D1(150), and the loss tangent tanδ at a temperature of 150°C and a strain of 50% is D50(150),
D1(90), D50(90), D1(150), and D50(150) are each between 0.5 and 2.0.
The value of D50(150) - D1(150) is less than 1.5.
It is preferable that the value of D50(90) - D1(90) is less than 0.5.
The toner according to this embodiment, having the above characteristics, exhibits a small change in the loss tangent with respect to changes in strain at both 90°C and 150°C. Therefore, the toner has similar viscoelasticity at high temperatures and high strain levels, and at low temperatures and low strain levels. Consequently, the viscoelasticity of the toner particles is easily maintained appropriately in both high-temperature, high-humidity and low-temperature, low-humidity environments, further suppressing both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments.

In the toner, D1(90), D50(90), D1(150), and D50(150) are preferably between 0.6 and 1.8, and more preferably between 0.8 and 1.6. By having D1(90), D50(90), D1(150), and D50(150) all within the above range, both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments are further suppressed, as described above.

The value of D50(150)-D1(150) in the toner is less than 1.5, preferably 1.2 or less, and more preferably 1.0 or less. By having the value of D50(150)-D1(150) within the above range, both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments are further suppressed, as described above.
Furthermore, there is no particular limit to the lower limit of the value of D50(150)-D1(150).

The D50(90)-D1(90) value in the toner is less than 0.5, preferably 0.4 or less, and more preferably 0.3 or less. By having the D50(90)-D1(90) value within the above range, both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments are further suppressed, as described above.
Furthermore, there is no particular limit to the lower limit of the value of D50(90)-D1(90).

The toner loss tangent can be calculated as follows:
Specifically, the toner to be measured is molded into a tablet shape using a press molding machine at room temperature (25°C) to prepare a sample for measurement. Then, using this sample for measurement, dynamic viscoelasticity measurements are performed using a rheometer under the following conditions, and the loss tangent tanδ at a temperature of 90°C or 150°C and a strain of 1% or 50% is determined from the obtained storage modulus and loss modulus curves, thereby obtaining D1(90), D50(90), D1(150), and D50(150).
-Measurement conditions-
Measuring device: Rheometer ARES-G2 (manufactured by T.A. Instruments Co., Ltd.)
Measurement jig: 8mm parallel plate; Gap: Adjusted to 3mm; Frequency: 1Hz

(Toner manufacturing method)
Next, a description of the toner manufacturing method according to this embodiment will be given.
The toner according to this embodiment is obtained by manufacturing toner particles and then, if necessary, adding an external additive to the toner particles.

Toner particles may be manufactured by either a dry process (e.g., kneading and grinding method) or a wet process (e.g., agglomeration, suspension polymerization, dissolution and suspension method). There are no particular restrictions on the manufacturing method of toner particles, and any well-known method may be used.
Among these methods, obtaining toner particles by the aggregation and coalescence method is preferable.

Specifically, for example, when manufacturing toner particles by an aggregation and coalescence method,
The toner particles are manufactured through the following steps: a resin particle dispersion in which resin particles that will become a binder are dispersed, and an internal resin particle dispersion in which internal resin particles will become internal resin particles (resin particle dispersion preparation step); a step of agglomerating resin particles (and other particles as needed) in the resin particle dispersion (and in the dispersion after mixing with other particle dispersions as needed) to form aggregated particles (aggregated particle formation step); and a step of heating the aggregated particle dispersion in which the aggregated particles are dispersed to fuse and combine the aggregated particles to form toner particles (fusion and combination step).

The details of each step are explained below.
The following explanation describes a method for obtaining toner particles containing a colorant and a release agent, but the colorant and release agent are used only as needed. Of course, other additives besides colorants and release agents may also be used.

-Resin particle dispersion preparation process-
First, a resin particle dispersion containing resin particles that will act as a binder is prepared, along with, for example, a coloring agent particle dispersion containing coloring agent particles and a release agent particle dispersion containing release agent particles.

Here, the resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

Examples of dispersion media used in resin particle dispersions include aqueous media.
Examples of aqueous media include water such as distilled water and deionized water, and alcohols. These may be used individually or in combination of two or more.

Examples of surfactants include anionic surfactants such as sulfate esters, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycol, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly noteworthy. Nonionic surfactants may be used in combination with anionic or cationic surfactants.
Surfactants may be used individually or in combination of two or more types.

In resin particle dispersions, common dispersion methods for dispersing resin particles in a dispersion medium include, for example, rotary shear homogenizers, ball mills with media, sand mills, and dyno mills. Depending on the type of resin particles, the resin particles may also be dispersed in the resin particle dispersion using, for example, a phase inversion emulsification method.
Phase inversion emulsification is a method in which the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, a base is added to the organic continuous phase (O phase) to neutralize it, and then an aqueous medium (W phase) is added. This causes a conversion of the resin from W/O to O/W (so-called phase inversion), resulting in a discontinuous phase, and the resin is dispersed in the aqueous medium in particulate form.

The volume-average particle size of the resin particles dispersed in the resin particle dispersion is preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and even more preferably 0.1 μm or more and 0.6 μm or less.
The volume-average particle size of the resin particles is measured using a laser diffraction particle size distribution analyzer (e.g., LA-700 manufactured by Horiba, Ltd.). The particle size distribution is obtained by subtracting the cumulative distribution from the smallest particle size side for each divided particle size range (channel), and the particle size that accounts for 50% of the total particle size is measured as the volume-average particle size D50v. The volume-average particle size of particles in other dispersions is measured in the same manner.

The resin particle content in the resin particle dispersion is preferably, for example, 5% to 50% by mass, and more preferably 10% to 40% by mass.

Furthermore, similar to the resin particle dispersion, colorant particle dispersions and release agent particle dispersions are also prepared. In other words, the volume-average particle size, dispersion medium, dispersion method, and particle content of the resin particle dispersion are the same for colorant particles dispersed in the colorant particle dispersion and release agent particles dispersed in the release agent particle dispersion.

Preparation of internally added resin particle dispersions Known methods for preparing internally added resin particle dispersions include emulsion polymerization, melt kneading using a Banbury mixer or kneader, suspension polymerization, and spray drying, but emulsion polymerization is preferred.

From the viewpoint of keeping the storage modulus G' and loss tangent tanδ of the internally added resin particles within a favorable range, it is preferable to use styrene-based monomers and (meth)acrylic acid-based monomers as monomers and polymerize them in the presence of a crosslinking agent.
Furthermore, it is preferable to carry out multiple emulsion polymerization steps in the production of the internally added resin particles.
The method for producing the internally added resin particles will be explained in more detail below.

The method for preparing the internal resin particle dispersion is as follows:
A step to obtain an emulsion containing monomers, a crosslinking agent, a surfactant, and water (emulsifier preparation step),
The process involves adding a polymerization initiator to the emulsion and heating it to polymerize the monomer (first emulsion polymerization step),
Preferably, the process includes a step (second emulsion polymerization step) in which an emulsion containing monomers and a crosslinking agent is added to the reaction solution after the first emulsion polymerization step, and the monomers are polymerized by heating.

- Emulsion preparation process -
This is a process to obtain an emulsion containing monomers, a crosslinking agent, a surfactant, and water.
It is preferable to obtain an emulsion by emulsifying the monomer, crosslinking agent, surfactant, and water using an emulsifier.
Examples of emulsifiers include rotary stirrers equipped with propeller-type, anchor-type, paddle-type, or turbine-type stirring blades, static mixers and other stationary mixers, homogenizers,
Examples include rotor-stator type emulsifiers such as Creamix, mill-type emulsifiers with grinding functions, high-pressure emulsifiers such as Manton-Gorin type pressure emulsifiers, high-pressure nozzle type emulsifiers that generate cavitation under high pressure, high-pressure impact type emulsifiers such as microfluidizers that apply shear force by causing liquids to collide under high pressure, ultrasonic emulsifiers that generate cavitation with ultrasound, and membrane emulsifiers that perform uniform emulsification through pores.

It is preferable to use styrene-based monomers and (meth)acrylic acid-based monomers as monomers.
The crosslinking agents described above are applicable.

Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonates, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycol, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Nonionic surfactants may be used in combination with anionic or cationic surfactants. Among these, anionic surfactants are preferred. Surfactants may be used individually or in combination of two or more.

The emulsified solution may contain a chain transfer agent. While there are no particular restrictions on the chain transfer agent, compounds containing a thiol component can be used. Specifically, alkyl mercaptans such as hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, and dodecyl mercaptan are preferred.

From the viewpoint of keeping the storage modulus G' of the internally added resin particles within a preferred range, the mass ratio of styrene monomers and (meth)acrylic acid monomers in the emulsion (styrene monomers/(meth)acrylic acid monomers) is preferably 0.2 or more and 1.1 or less.
Furthermore, from the viewpoint of keeping the storage modulus G' of the internally added resin particles within a favorable range, it is preferable that the content of the crosslinking agent relative to the entire emulsion is 0.5% by mass or more and 3% by mass or less.

-First emulsion polymerization process-
This process involves adding a polymerization initiator to an emulsified solution and heating it to polymerize the monomers.
Here, during polymerization, it is preferable to stir the emulsion (reaction solution) containing the polymerization initiator with a stirrer.
Examples of agitators include rotary agitators equipped with propeller-type, anchor-type, paddle-type, or turbine-type agitators.
Ammonium persulfate is preferred as the polymerization initiator.
Furthermore, when using a polymerization initiator, the viscoelasticity of the resulting internally added resin particles can be controlled by adjusting the amount of polymerization initiator added. For example, reducing the amount of polymerization initiator makes it easier to obtain resin particles with a high storage modulus G'.

-Second emulsion polymerization step-
This step involves adding an emulsion containing monomers to the reaction solution after the first emulsion polymerization step and heating it to polymerize the monomers.
During polymerization, it is preferable to stir the reaction solution in the same manner as in the first emulsion polymerization step.
In this process, the viscoelasticity of the resulting internally added resin particles may be controlled by adjusting the time spent adding the emulsion containing the monomer. For example, increasing the time spent adding the emulsion containing the monomer makes it easier to obtain resin particles with a high storage modulus G'. The time spent adding the emulsion containing the monomer can be, for example, in the range of 2 hours to 5 hours.
Furthermore, in this process, the viscoelasticity of the resulting internally added resin particles may be controlled by adjusting the temperature during stirring of the reaction solution. For example, lowering the temperature during stirring of the reaction solution makes it easier to obtain internally added resin particles with a high storage modulus G'. Examples of temperatures for stirring the reaction solution include a range of 55°C to 75°C.
For emulsions containing monomers, it is preferable to obtain the emulsion by emulsifying the monomer, surfactant, and water using an emulsifier.

-Agglomerated particle formation process-
Next, the resin particle dispersion is mixed with the coloring agent particle dispersion, the mold release agent particle dispersion, and the internally added resin particle dispersion.
Then, in the mixed dispersion, the resin particles, colorant particles, release agent particles, and internally added resin particles are heteroaggregated to form aggregated particles containing resin particles, colorant particles, release agent particles, and internally added resin particles, which have a diameter close to the diameter of the target toner particles.

Specifically, for example, a flocculant is added to a mixed dispersion, the pH of the mixed dispersion is adjusted to be acidic (for example, pH 2 to 5), a dispersion stabilizer is added as needed, and then the mixture is heated to a temperature of the glass transition temperature of the resin particles (specifically, for example, above the glass transition temperature of the resin particles -30°C or below the glass transition temperature -10°C) to flocce the particles dispersed in the mixed dispersion and form flocculated particles.
In the agglomerated particle formation step, for example, the mixed dispersion may be stirred in a rotary shear homogenizer, the above-mentioned flocculant may be added at room temperature (e.g., 25°C), the pH of the mixed dispersion may be adjusted to acidic (e.g., pH 2 to 5), a dispersion stabilizer may be added as needed, and then the above-mentioned heating may be performed.

In this process, the dispersion state of the internally added resin particles in the resulting toner particles may be controlled by adjusting the temperature of the mixed dispersion when adding the flocculant. For example, lowering the temperature of the mixed dispersion improves the dispersibility of the internally added resin particles. Examples of the temperature of the mixed dispersion include a range of 5°C to 40°C.
Furthermore, in this process, the dispersion state of the internally added resin particles in the resulting toner particles may be controlled by adjusting the stirring speed after the addition of the flocculant. For example, increasing the stirring speed after the addition of the flocculant improves the dispersibility of the internally added resin particles.

Examples of flocculants include surfactants with opposite polarity to the surfactant used as a dispersant added to a mixed dispersion, inorganic metal salts, and metal complexes with a valency of two or more. In particular, when a metal complex is used as a flocculant, the amount of surfactant used is reduced and the electrostatic properties are improved.
Additives that form complexes or similar bonds with the metal ions of the flocculant may be used as needed. Chelating agents are preferably used as such additives.

Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, as well as inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide.
As a chelating agent, a water-soluble chelating agent may be used. Examples of chelating agents include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid, as well as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA).
The amount of chelating agent to be added is preferably 0.01 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of resin particles, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass.

-Fusion/unification process-
Next, the dispersion of aggregated particles is heated to a temperature above the glass transition temperature of the resin particles (for example, 10 to 30°C higher than the glass transition temperature of the resin particles) to fuse and combine the aggregated particles and form toner particles.

Toner particles are obtained through the above process.
Furthermore, after obtaining an aggregated particle dispersion in which aggregated particles are dispersed, toner particles may be manufactured by further mixing the aggregated particle dispersion, a resin particle dispersion in which resin particles are dispersed, and an internal resin particle dispersion in which internal resin particles are dispersed, and agglomerating the aggregated particles so that the resin particles and internal resin particles adhere to the surface of the aggregated particles to form second aggregated particles; and heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and combine the second aggregated particles to form toner particles with a core/shell structure.

In the step of forming the second aggregated particle, the addition of the resin particle dispersion and the internal resin particle dispersion, and the adhesion of the resin particles and internal resin particles to the surface of the aggregated particle, may be repeated multiple times. By repeating this process multiple times, toner particles can be obtained in which the internal resin particles are evenly distributed in both the surface and central regions of the toner particle.

After the fusion and coalescence process is complete, the toner particles formed in the solution are subjected to known washing, solid-liquid separation, and drying processes to obtain dried toner particles.
The washing process should be thoroughly performed using ion-exchanged water for displacement washing, considering the electrostatic charge. The solid-liquid separation process is not particularly restricted, but suction filtration, pressure filtration, etc., are preferable for productivity. The drying process is also not particularly restricted, but freeze-drying, air-flow drying, fluidized bed drying, vibratory fluidized bed drying, etc., are preferable for productivity.

The toner according to this embodiment is manufactured, for example, by adding an external additive to the obtained dried toner particles and mixing them. Mixing can be performed using, for example, a V-blender, Henschel mixer, or Lödige mixer. Furthermore, if necessary, coarse particles of the toner may be removed using a vibrating screen separator, air screen separator, or the like.

[Developer]
The developer according to this embodiment includes at least the toner according to this embodiment.
The developer according to this embodiment may be a one-component developer containing only the toner according to this embodiment, or it may be a two-component developer mixed with the toner and a carrier.

There are no particular restrictions on the carriers, and known carriers can be used. Examples of carriers include coated carriers in which a coating resin is applied to the surface of a core material made of magnetic powder; magnetic powder dispersed carriers in which magnetic powder is dispersed and blended in a matrix resin; and resin-impregnated carriers in which resin is impregnated into porous magnetic powder.
Furthermore, magnetic powder dispersed carriers and resin-impregnated carriers may be carriers in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

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

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 resin or modified thereof containing organosiloxane bonds, fluororesin, polyester, polycarbonate, phenolic resin, epoxy resin, and the like.
Furthermore, the coating resin and matrix resin may contain conductive particles or other additives.
Examples of conductive particles include metals such as gold, silver, and copper, as well as carbon black, titanium dioxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

To coat the surface of the core material with a coating resin, one method is to coat it with a coating layer-forming solution prepared by dissolving the coating resin and, if necessary, various additives in a suitable solvent. The solvent is not particularly limited and should be selected considering the coating resin used, its suitability for coating, etc.
Specific resin coating methods include the immersion method, in which the core material is immersed in a coating layer forming solution; the spray method, in which the coating layer forming solution is sprayed onto the surface of the core material; the fluidized bed method, in which the coating layer forming solution is sprayed onto the core material while it is suspended by fluidized air; and the kneader coater method, in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed.

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

The following describes embodiments of the present invention, but the present invention is not limited to these embodiments. In the following description, unless otherwise specified, "parts" and "%" all refer to mass. The viscosity of the electrostatic image developing toner, the maximum endothermic peak temperature, and the absorbance at each wavelength were measured by the method described above.
Furthermore, the viscosity of the toner, the maximum endothermic peak temperature, and the absorbance at each wavelength were measured using the method described above.

[Preparation of internal resin particle dispersion]
<Preparation of internal resin particle dispersion 1>
- Styrene: 47.9 parts - n-butyl acrylate: 51.8 parts - β-carboxyethyl acrylate: 0.3 parts - Anionic surfactant (Dow Chemical, Dowfax 2A1): 0.8 parts - Butanediol diacrylate: 1.65 parts The above raw materials were mixed and dissolved, and 60 parts of ion-exchanged water were added to disperse and emulsify in a flask to prepare an emulsion.
Next, 1.3 parts of anionic surfactant (Dowfax 2A1, manufactured by Dow Chemical) were dissolved in 90 parts of deionized water, 1 part of the emulsion was added to it, and then 10 parts of deionized water in which 5.4 parts of ammonium persulfate was dissolved was added.
Subsequently, the remaining emulsion was added over 180 minutes, and the flask was purged with nitrogen. The solution in the flask was then heated in an oil bath to 65°C while stirring, and emulsion polymerization was continued for 500 minutes to obtain internally added resin particle dispersion 1 with a solid content of 24.5% by mass.

<Preparation of internal resin particle dispersions 2-10 and C1-C2>
Internal resin particle dispersions 2 to 10 and C1 to C2 were obtained in the same manner as internal resin particle dispersion 1, except that the amount of styrene added, the amount of n-butyl acrylate added, the amount of acrylic acid added, the amount of β-carboxyethyl acrylate added, the total amount of anionic surfactant added, the amount of butanediol diacrylate added (crosslinking agent in the table), the amount of ammonium peroxide added, the temperature at which the oil bath was heated (polymerization temperature in the table), the time for which the remaining emulsion was added (addition time in the table), and the time for which emulsion polymerization was continued after heating (holding time in the table) were as shown in Table 1.

Table 2 shows the results obtained by determining the minimum (G' (small)) and maximum (G' (large)) storage modulus G', number-average particle size, and SP value (S) of the resin particles contained in the obtained internally added resin particle dispersion and comparative resin particle dispersion, using the method described above, at temperatures between 23°C and 80°C.

[Preparation of resin particle dispersion]
<Preparation of amorphous resin particle dispersion 1>
- Terephthalic acid: 28 parts - Fumaric acid: 174 parts - Bisphenol A ethylene oxide 2 molar adduct: 26 parts - Bisphenol A propylene oxide 2 molar adduct: 542 parts The above materials were charged into a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor and rectification column, and the temperature was raised to 190°C over 1 hour. 1.2 parts of dibutyltin oxide were added for every 100 parts of the above materials. The temperature was raised to 240°C over 6 hours while distilling off the water produced, and the dehydration condensation reaction was continued at 240°C for 3 hours, after which the reactants were cooled.

The reaction mixture was transferred in a molten state to a Cavitron CD1010 (manufactured by Eurotech) at a rate of 100 g per minute. Simultaneously, a separately prepared 0.37% by mass aqueous ammonia solution was transferred to the Cavitron CD1010 at a rate of 0.1 liters per minute while being heated to 120°C in a heat exchanger. The Cavitron CD1010 was operated under conditions of a rotor rotation speed of 60 Hz and a pressure of ⁵ kg/cm² to obtain a resin particle dispersion containing amorphous polyester resin particles with a volume-average particle size of 175 nm. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20% by mass, resulting in amorphous resin particle dispersion 1.
The obtained amorphous polyester resin had an SP value (R) of 9.43.

<Preparation of amorphous resin particle dispersion 2>
- Styrene: 72 parts - n-butyl acrylate: 27 parts - β-carboxyethyl acrylate: 1.3 parts - dodecanethiol: 2 parts The mixture of the above materials was dispersed and emulsified in a flask in a surfactant solution prepared by dissolving 1.2 parts by mass of anionic surfactant (TaycaPower, manufactured by Tayca Co., Ltd.) in 100 parts by mass of ion-exchanged water. Next, while stirring the flask, an aqueous solution prepared by dissolving 6 parts by mass of ammonium persulfate in 50 parts by mass of ion-exchanged water was added over 20 minutes. After purging with nitrogen, the contents of the flask were heated in an oil bath while stirring until they reached 75°C, and emulsion polymerization was continued by maintaining the temperature at 75°C for 4 hours. In this way, a resin particle dispersion liquid was obtained in which amorphous styrene acrylic resin particles with a volume average particle size of 160 nm and a weight average molecular weight of 56000 were dispersed. Ion-exchanged water was added to this resin particle dispersion to adjust the solid content to 31.4% by mass, thereby obtaining amorphous resin particle dispersion 2.
The obtained amorphous styrene-acrylic resin had an SP value (R) of 9.14.

<Preparation of crystalline resin particle dispersion>
1,10-Dodecanediol: 225 parts, 1,6-Hexanediol: 143 parts The above materials were charged into a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor and rectification column, and the temperature was raised to 160°C over 1 hour, at which point 0.8 parts by mass of dibutyltin oxide was added. The temperature was raised to 180°C over 6 hours while distilling off the water produced, and the dehydration condensation reaction was continued at 180°C for 5 hours. After that, the temperature was gradually raised to 230°C under reduced pressure, and the mixture was stirred at 230°C for 2 hours. The reactants were then cooled. After cooling, solid-liquid separation was performed, and the solids were dried to obtain a crystalline polyester resin.

- Crystalline polyester resin: 100 parts - Methyl ethyl ketone: 40 parts - Isopropyl alcohol: 30 parts - 10% aqueous ammonia solution: 6 parts The above materials were added to a 3-liter jacketed reaction vessel (Tokyo Rikakikai Co., Ltd.: BJ-30N) equipped with a condenser, thermometer, water dropper, and anchor vanes, and the resin was dissolved while stirring at 100 rpm while maintaining the temperature at 80°C in a water-circulating constant temperature bath. Then, the water-circulating constant temperature bath was set to 50°C, and a total of 400 parts of ion-exchanged water, which had been kept at 50°C, was added dropwise at a rate of 7 parts by mass/min to invert the phase and obtain an emulsion. 576 parts by mass of the obtained emulsion and 500 parts by mass of ion-exchanged water were placed in a 2-liter round-bottom flask and set in an evaporator (Tokyo Rikakikai Co., Ltd.) equipped with a vacuum control unit via a trap bulb. The solution was heated in a 60°C water bath while rotating the round-bottom flask, and the pressure was reduced to 7 kPa while taking care to prevent bumping, to remove the solvent. The volume-average particle size D50v of the resin particles in this dispersion was 185 nm. Subsequently, deionized water was added to obtain a crystalline resin particle dispersion with a solid content concentration of 22.1% by mass.

<Preparation of colorant dispersion>
- Cyanide pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15:3 (copper phthalocyanine)): 98 parts - Anionic surfactant (manufactured by Teika Co., Ltd., TaycaPower): 2 parts - Ion-exchanged water: 420 parts The above were mixed and dissolved, and dispersed for 10 minutes using a homogenizer (IKA Ultra-Turrax) to obtain a colorant dispersion with a median particle size of 164 nm and a solid content of 21.1% by mass.

<Preparation of mold release agent dispersion>
- Synthetic wax (manufactured by Nippon Seiro Co., Ltd., FNP92, melting temperature Tw: 92°C): 50 parts - Anionic surfactant (manufactured by Teika Co., Ltd., TaycaPower): 1 part - Ion-exchanged water: 200 parts The above materials were mixed and heated to 130°C, dispersed using a homogenizer (IKA Corporation, Ultra-Turrax T50), and then dispersed using a Manton-Gorin high-pressure homogenizer (Gorin Corporation) to obtain a release agent dispersion (solid content 20% by mass) in which release agent particles were dispersed. The volume-average particle size of the release agent particles was 214 nm.

<Toner 1>
- Amorphous resin particle dispersion 1: 169 parts - Internally added resin particle dispersion 1: 33 parts - Crystalline resin particle dispersion: 53 parts - Release agent dispersion: 25 parts - Colorant dispersion: 33 parts - Anionic surfactant (Dow Chemical, Dowfax 2A1): 4.8 parts The above raw materials, with the liquid temperature adjusted to 10°C, were placed in a 3L cylindrical stainless steel container and mixed by dispersing them for 2 minutes while applying shear force at 4000 rpm using a homogenizer (IKA, Ultra-Turrax T50).
Next, 1.75 parts of a 10% aqueous solution of aluminum sulfate in nitric acid was gradually added dropwise as a flocculant, and the mixture was dispersed and mixed for 10 minutes at a homogenizer rotation speed of 10,000 rpm to obtain the raw material dispersion.

Subsequently, the raw material dispersion was transferred to a polymerization vessel equipped with a stirring device using two paddle blades and a thermometer. The stirring speed was set to 550 rpm and heating was started with a mantle heater to promote the growth of aggregated particles at 40°C. At this time, the pH of the raw material dispersion was controlled to a range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M sodium hydroxide aqueous solution. The mixture was maintained within this pH range for about 2 hours to form aggregated particles.
Next, a dispersion solution prepared by mixing 1 part amorphous resin particle dispersion and 1 part internally added resin particle dispersion was added and held for 60 minutes to allow the resin particles of the binder resin and the internally added resin particles to adhere to the surface of the aggregated particles. The temperature was then raised to 53°C, and then 1 part amorphous resin particle dispersion was added and held for 60 minutes to allow the resin particles of the binder resin to adhere to the surface of the aggregated particles.

The aggregated particles were sorted while checking their size and morphology using an optical microscope and a multisizer 3. Then, the pH was adjusted to 7.8 using a 5% sodium hydroxide aqueous solution and held for 15 minutes.
Subsequently, the pH was raised to 8.0 to fuse the aggregated particles, and then the temperature was increased to 85°C. After confirming that the aggregated particles had fused using an optical microscope, heating was stopped after 2 hours, and the mixture was cooled at a rate of 1.0°C/min. The mixture was then sieved with a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles 1.

100 parts of the obtained toner particles and 0.7 parts of dimethyl silicone oil-treated silica particles (RY200, manufactured by Nippon Aerosil Co., Ltd.) were mixed in a Henschel mixer to obtain toner 1.

<Toner 2-11, Toner C1-C2>
Toners 2 to 11 and toners C1 to C2 were obtained in the same manner as toner 1, except that instead of internally added resin particle dispersion 1, an internally added resin particle dispersion of the type shown in Table 3 or a comparative resin particle dispersion was used in an amount such that the content of resin particles (i.e., internally added resin particles or comparative resin particles) relative to the total toner particles was the value shown in Table 3.

<Toner 12-14>
Toners 12 to 14 were obtained in the same manner as toner 1, except that the amount of crystalline resin particle dispersion added was adjusted so that the content of crystalline resin relative to the total binder resin was the value shown in Table 3.

<Toner 15>
Toner 15 was obtained in the same manner as toner 1, except that instead of using amorphous resin particle dispersion 1, amorphous resin particle dispersions of the types shown in Table 3 were used in the amounts shown in Table 3.

<Toner 16>
Toner 16 was obtained in the same manner as toner 1, except that the rotation speed of the homogenizer was changed from 10,000 rpm to 5,000 rpm.

<Toner 17>
Toner 17 was obtained in the same manner as toner 1, except that the amount of crystalline resin particle dispersion added was adjusted so that the content of crystalline resin relative to the total binder resin was the value shown in Table 4.

<Toner 18>
Toner 18 was obtained in the same manner as toner 1, except that the amount of internal resin particle dispersion 1 used was such that the content of internal resin particles relative to the total toner particles was as shown in Table 4, and the amount of crystalline resin particle dispersion added was adjusted so that the content of crystalline resin relative to the total binder resin was as shown in Table 4.

<Toner 19>
Toner 19 was obtained in the same manner as toner 1, except that the pH at the time of fusion of aggregated particles was changed from 8.0 to 9.0.

<Toner 20>
Toner 20 was obtained in the same manner as toner 1, except that the pH at the time of fusion of aggregated particles was changed from 8.0 to 5.5.

<Toner 21>
Toner 21 was obtained in the same manner as toner 1, except that the internal resin particle dispersion 1 was used in an amount such that the content of internal resin particles relative to the total toner particles was as shown in Table 4, and the pH at the time of fusion of aggregated particles was changed from 8.0 to 9.5.

<Toner 22>
Toner 22 was obtained in the same manner as toner 1, except that the internal resin particle dispersion 1 was used in an amount such that the content of internal resin particles relative to the total toner particles was the value shown in Table 5, the amount of internal resin particles 1 was changed from 10 to 19, and the pH at the time of fusion of aggregated particles was changed from 8.0 to 6.0.

<Toner 23-27>
Toners 23 to 27 were obtained in the same manner as toner 1, except that instead of internal resin particle dispersion 1, an internal resin particle dispersion of the type shown in Table 4 was used in an amount such that the content of internal resin particles relative to the total toner particles was the value shown in Table 4, and the amount of crystalline resin particle dispersion added was adjusted so that the content of crystalline resin relative to the total binder resin was the value shown in Table 4.

<Toner C3>
- Amorphous resin particle dispersion 1: 169 parts - Internally added resin particle dispersion 1: 33 parts - Crystalline resin particle dispersion: 53 parts - Release agent dispersion: 25 parts - Colorant dispersion: 33 parts - Anionic surfactant (Dow Chemical, Dowfax 2A1): 4.8 parts The above raw materials, with the liquid temperature adjusted to 30°C, were placed in a 3L cylindrical stainless steel container and mixed by dispersing with a homogenizer (IKA, Ultra-Turrax T50) at 4000 rpm while applying shear force for 2 minutes.
Next, 1.75 parts of a 10% aqueous solution of aluminum sulfate in nitric acid was gradually added dropwise as a flocculant, and the mixture was dispersed and mixed for 3 minutes at a homogenizer rotation speed of 4000 rpm to obtain the raw material dispersion.

Subsequently, the raw material dispersion was transferred to a polymerization vessel equipped with a stirring device using two paddle blades and a thermometer. The stirring speed was set to 550 rpm and heating was started with a mantle heater to promote the growth of aggregated particles at 40°C. At this time, the pH of the raw material dispersion was controlled to a range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M sodium hydroxide aqueous solution. The mixture was maintained within this pH range for about 2 hours to form aggregated particles.
Next, a dispersion prepared by mixing 1 part amorphous resin particle dispersion and 1 part internally added resin particle dispersion was added and held for 60 minutes to allow the binder resin particles and internally added resin particles to adhere to the surface of the aggregated particles. The temperature was then raised to 53°C, and then 21 parts amorphous resin particle dispersion was added and held for 60 minutes to allow the binder resin particles to adhere to the surface of the aggregated particles.

The aggregated particles were sorted while checking their size and morphology using an optical microscope and a multisizer 3. Then, the pH was adjusted to 7.8 using a 5% sodium hydroxide aqueous solution and held for 15 minutes.
Subsequently, the pH was raised to 8.0 to fuse the aggregated particles, and then the temperature was increased to 85°C. After confirming the fusion of the aggregated particles using an optical microscope, heating was stopped after 2 hours, and the mixture was cooled at a rate of 1.0°C/min. The mixture was then sieved with a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles C3.

100 parts of the obtained toner particles and 0.7 parts of dimethyl silicone oil-treated silica particles (RY200, manufactured by Nippon Aerosil Co., Ltd.) were mixed in a Henschel mixer to obtain toner C3.

<Toner C4>
- Amorphous resin particle dispersion 1: 169 parts - Internally added resin particle dispersion 1: 41 parts - Crystalline resin particle dispersion: 53 parts - Release agent dispersion: 25 parts - Colorant dispersion: 33 parts - Anionic surfactant (Dow Chemical, Dowfax 2A1): 4.8 parts The above raw materials, with the liquid temperature adjusted to 30°C, were placed in a 3L cylindrical stainless steel container and mixed by dispersing with a homogenizer (IKA, Ultra-Turrax T50) at 4000 rpm while applying shear force for 2 minutes.
Next, 1.75 parts of a 10% aqueous solution of aluminum sulfate in nitric acid was gradually added dropwise as a flocculant, and the mixture was dispersed and mixed for 3 minutes at a homogenizer rotation speed of 4000 rpm to obtain the raw material dispersion.

Subsequently, the raw material dispersion was transferred to a polymerization vessel equipped with a stirring device using two paddle blades and a thermometer. The stirring speed was set to 550 rpm and heating was started with a mantle heater to promote the growth of aggregated particles at 40°C. At this time, the pH of the raw material dispersion was controlled to a range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M sodium hydroxide aqueous solution. The mixture was maintained within this pH range for about 2 hours to form aggregated particles.
Next, 1:42 parts of amorphous resin particle dispersion were added, and the mixture was held for 60 minutes to allow the resin particles of the binder resin to adhere to the surface of the aggregated particles.

The aggregated particles were sorted while checking their size and morphology using an optical microscope and a multisizer 3. Then, the pH was adjusted to 7.8 using a 5% sodium hydroxide aqueous solution and held for 15 minutes.
Subsequently, the pH was raised to 8.0 to fuse the aggregated particles, and then the temperature was increased to 85°C. After confirming that the aggregated particles had fused using an optical microscope, heating was stopped after 2 hours, and the mixture was cooled at a rate of 1.0°C/min. The mixture was then sieved with a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles C4.

100 parts of the obtained toner particles and 0.7 parts of dimethyl silicone oil-treated silica particles (RY200, manufactured by Nippon Aerosil Co., Ltd.) were mixed using a Henschel mixer to obtain toner C4.

<Toner C5>
- Amorphous resin particle dispersion 1: 169 parts - Crystalline resin particle dispersion: 53 parts - Release agent dispersion: 25 parts - Colorant dispersion: 33 parts - Anionic surfactant (Dow Chemical, Dowfax 2A1): 4.8 parts The above raw materials, with the liquid temperature adjusted to 30°C, were placed in a 3L cylindrical stainless steel container and mixed by dispersing them for 2 minutes while applying shear force at 4000 rpm using a homogenizer (IKA, Ultra-Turrax T50).
Next, 1.75 parts of a 10% aqueous solution of aluminum sulfate in nitric acid was gradually added dropwise as a flocculant, and the mixture was dispersed and mixed for 3 minutes at a homogenizer rotation speed of 4000 rpm to obtain the raw material dispersion.

Subsequently, the raw material dispersion was transferred to a polymerization vessel equipped with a stirring device using two paddle blades and a thermometer. The stirring speed was set to 550 rpm and heating was started with a mantle heater to promote the growth of aggregated particles at 40°C. At this time, the pH of the raw material dispersion was controlled to a range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M sodium hydroxide aqueous solution. The mixture was maintained within this pH range for about 2 hours to form aggregated particles.
Next, a dispersion was prepared by mixing 1:42 parts amorphous resin particle dispersion and 1:41 parts internally added resin particle dispersion. This dispersion was divided in half and added in two separate additions. The mixture was then held for 60 minutes to allow the binder resin particles and internally added resin particles to adhere to the surface of the aggregated particles.

The aggregated particles were sorted while checking their size and morphology using an optical microscope and a multisizer 3. Then, the pH was adjusted to 7.8 using a 5% sodium hydroxide aqueous solution and held for 15 minutes.
Subsequently, the pH was raised to 8.0 to fuse the aggregated particles, and then the temperature was increased to 85°C. After confirming the fusion of the aggregated particles using an optical microscope, heating was stopped after 2 hours, and the mixture was cooled at a rate of 1.0°C/min. The mixture was then sieved with a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles C5.

100 parts of the obtained toner particles and 0.7 parts of dimethyl silicone oil-treated silica particles (RY200, manufactured by Nippon Aerosil Co., Ltd.) were mixed using a Henschel mixer to obtain toner C5.

Tables 3 and 4 show the type of internally added resin particle dispersion or comparative resin particle dispersion in the obtained toner ("Particle Type" in the table), the content of internally added resin particles or comparative resin particles relative to the total toner particles ("Particle Content C (%)" in the table), the content of crystalline resin relative to the total binder resin ("Crystalline Content (%)" in the table), and the type of amorphous resin particle dispersion ("Amorphous Type" in the table).
Furthermore, the storage modulus G'("G'(Pa)" in the table) and the temperature at which the specific modulus of the excluded components is reached ("Temperature reached (°C)" in the table) were determined using the method described above, and these results are shown in Tables 3 and 4.
Furthermore, the values of D1(90), D50(90), D1(150), D50(150), D50(150)-D1(150) (indicated as "Difference (150)" in the table), D50(90)-D1(90) (indicated as "Difference (90)" in the table), the storage modulus G' in the range of 23°C to 50°C (indicated as "G'(Pa)" in the table), and the difference (SP value (S) - SP value (R)) (indicated as "SP value difference" in the table) obtained for the toner are shown in Tables 3 and 4, obtained using the method described above.

<Preparation of Developers 1-27 and Developers C1-C5>
Eight parts of the obtained toner were mixed with 100 parts of the carrier described below to obtain developers 1-27 and C1-C5.

-Creating a Career-
- 100 parts of ferrite particles (average particle size 50 μm) - 14 parts of toluene - 3 parts of styrene/methyl methacrylate copolymer (copolymerization ratio 15/85) - 0.2 parts of carbon black The above components, excluding the ferrite particles, were dispersed in a sand mill to prepare a dispersion. This dispersion was then placed together with the ferrite particles in a vacuum-degassed kneader and dried under reduced pressure while stirring to obtain a carrier.

[Preparation of cleaning blades 1-8 and C1]
Cleaning blades made of polyurethane were obtained according to the manufacturing method described in Japanese Patent No. 4788240. For each cleaning blade, the 100% modulus (α23 edge, α30 edge) of each part was measured using the measurement method described above. The results are shown in Tables 5 and 6. The relationship between the content X (mass%) of the internally added resin particles relative to the toner particles and the 100% modulus α23 edge at 23°C at the contact part of the cleaning blade (X/α23 edge) is also shown in Tables 5 and 6.

<Examples 1-42, Comparative Examples 1-3>
The developer and cleaning blade were mounted on the "ApeosPort-VI C7771" image forming apparatus manufactured by Fujifilm Business Innovation Co., Ltd., according to the combinations shown in Tables 5 and 6, to obtain each example of the image forming apparatus.

<Evaluation of chipping in the cleaning blade>
Using the image forming apparatus for each example, 300,000 images with an image density of 1% were printed on A4 paper under low temperature and low humidity conditions (10°C, 15% RH). Afterward, the cleaning blades were removed from each image forming apparatus, and their tips were observed with a laser microscope. The chipping of the cleaning blades was evaluated according to the following criteria. The results are shown in each table.
A: No chipping was observed on the cleaning blade.
B: The number of defects observed was less than 1 per cm.
C: Two or more defects were observed per cm, and three or fewer per cm.
D: More than 4 chips/cm or large chips were observed.

<Evaluation of linear image defects>
Using the image forming apparatus for each example, 300,000 images with an image density of 8% were printed on A4 paper under high temperature and high humidity conditions (30°C, 90% RH). Afterward, the electrophotographic photoreceptor was removed from each image forming apparatus, and the exposed surface of the electrophotographic photoreceptor was observed with a laser microscope. The coverage rate of residual toner and other deposits on the surface of the electrophotographic photoreceptor was determined using the following formula. Then, streaky image defects were evaluated according to the following criteria. The results are shown in each table.
Coverage = Area of attached material / Area of photoreceptor surface A: Coverage was 0%.
B: The coverage rate was 1% or less.
C: The coverage rate was between 1% and 5%.
D: The coverage rate was over 5%.

Based on the above results, the image forming apparatus of this embodiment suppressed both chipping of the cleaning blade in low-temperature, low-humidity environments and filming in high-temperature, high-humidity environments compared to the image forming apparatus of the comparative example.

10 Image forming apparatus 12 Photoreceptor 14 Charging member 15 Charging device 16 Electrostatic image forming apparatus 18 Developing device 20 Transfer member 22 Cleaning device 24 Static elimination device 26 Fixing device 30A Recording medium 31 Transfer device 36 Control device

220, 3422B Cleaning blade 12 Electrophotographic photoreceptor 3421B Contact member 3422B Substrate layer

Claims (13)

Electrophotographic photoreceptor,
A charging device for charging the surface of the electrophotographic photoreceptor,
A static charge image forming apparatus for forming a static charge image on the surface of the charged electrophotographic photoreceptor,
A developing apparatus that contains a developer containing toner, and uses the developer to develop the electrostatic latent image formed on the surface of the electrophotographic photoreceptor to form a toner image,
A cleaning device having a cleaning blade that cleans the surface of the electrophotographic photoreceptor by bringing a contact portion into contact with the surface of the electrophotographic photoreceptor,
A transfer device for transferring the toner image onto the surface of a recording medium,
Equipped with,
The cleaning blade has a contact portion and a base material layer,
The toner comprises toner particles containing a binder resin and resin particles, and an external additive.
The aforementioned binder resin is a polyester resin.
The aforementioned resin particles are crosslinked resin particles, which are styrene (meth)acrylic resin particles.
An image forming apparatus in which the relationship between the content X (mass%) of the resin particles relative to the toner particles and the 100% modulus α23 edge at 23°C of the contact portion of the cleaning blade satisfies 0.12 ≤ X / α23 edge ≤ 7.5. The image forming apparatus according to claim 1, wherein the 100% modulus α23 edge of the contact portion of the cleaning blade at 23°C is 4 MPa or more and 18 MPa or less. The image forming apparatus according to claim 1 or 2, wherein the 100% modulus α23base of the substrate layer of the cleaning blade at 23°C is lower than the 100% modulus α23edge of the contact portion at 23°C. The image forming apparatus according to any one of claims 1 to 3, wherein the content of the resin particles is 2% by mass or more and 30% by mass or less relative to the toner particles. The image forming apparatus according to any one of claims 1 to 4, wherein the relationship between the content X (mass%) of the resin particles relative to the toner particles and the 100% modulus α30 edge at 30°C of the contact portion of the cleaning blade satisfies 0.14 ≤ X / α30 edge ≤ 9.8. The image forming apparatus according to any one of claims 1 to 5, wherein the number-average particle size of the resin particles is 60 nm or more and 300 nm or less. The image forming apparatus according to any one of claims 1 to 6, wherein, in the dynamic viscoelasticity measurement of the resin particles when the temperature is increased by 2°C/min, the storage modulus G' in the range of 23°C to 80°C is 1 × ^10⁵ Pa or more and 5 × ^10⁷ Pa or less. The image forming apparatus according to claim 7, wherein, in a dynamic viscoelasticity measurement of the components obtained by removing the resin particles from the toner particles when the temperature is raised by 2°C/min, the storage modulus G' in the range of 23°C to 50°C is 1 × ^10⁸ Pa or more, and the temperature at which the storage modulus G' reaches less than 1 × ^10⁵ Pa is 65°C to 90°C. In the dynamic viscoelasticity measurement of the toner, when the loss tangent tanδ at a temperature of 90°C and a strain of 1% is D1(90), the loss tangent tanδ at a temperature of 90°C and a strain of 50% is D50(90), the loss tangent tanδ at a temperature of 150°C and a strain of 1% is D1(150), and the loss tangent tanδ at a temperature of 150°C and a strain of 50% is D50(150),
D1(90), D50(90), D1(150), and D50(150) are each between 0.5 and 2.0.
The value of D50(150) - D1(150) is less than 1.5.
The image forming apparatus according to any one of claims 1 to 8, wherein the value of D50(90)-D1(90) is less than 0.5. The image forming apparatus according to any one of claims 1 to 9 , wherein the toner comprises silica particles as the external additive. The image forming apparatus according to claim 10 , wherein the toner has titanium oxide particles together with the silica particles as an external additive. The image forming apparatus according to any one of claims 1 to 11 , wherein the content of the external additive is 0.01% by mass or more and 5% by mass or less with respect to the toner particles. Electrophotographic photoreceptor,
A developing apparatus that contains a developer containing toner, and uses the developer to develop the electrostatic charge image formed on the surface of the electrophotographic photoreceptor to form a toner image,
A cleaning device having a cleaning blade that cleans the surface of the electrophotographic photoreceptor by bringing a contact portion into contact with the surface of the electrophotographic photoreceptor,
Equipped with,
The cleaning blade has the contact portion and the base material layer,
The toner comprises toner particles containing a binder resin and resin particles, and an external additive.
The aforementioned binder resin is a polyester resin.
The aforementioned resin particles are crosslinked resin particles, which are styrene (meth)acrylic resin particles.
A process cartridge for attachment to and detachment from an image forming apparatus, wherein the relationship between the content X (mass%) of the resin particles relative to the toner particles and the 100% modulus α23edge at 23°C of the contact portion of the cleaning blade satisfies 0.12 ≤ X / α23edge ≤ 7.5.