Image forming apparatus and process cartridge

Abstract

To provide an image forming apparatus that prevents slip-through of a removed object from a cleaning blade after continuously forming images.SOLUTION: An image forming apparatus comprises: an electrophotographic photoreceptor; an electrifying device; an electrostatic charge image forming device; a developing device that stores developer including toner and forms a toner image; a cleaning device having a cleaning blade that cleans a surface of the electrophotographic photoreceptor; and a transfer device that transfers the toner image to a surface of a recording medium. The toner has a toner particle including a binder resin and resin particles, and an external additive. An impact modulus of elasticity A and a 100% modulus B of a member constituting a contact part of the cleaning blade in contact with the electrophotographic photoreceptor, and a content ratio C of the resin particles to all toner particles satisfy the following formula (1) and the following formula (2). Formula (1): 0.045≤content ratio C of resin particles / impact modulus of elasticity A≤1.160. Formula (2): 0.29≤content ratio C of resin particles / 100% modulus B≤4.53.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and a process cartridge. [Background technology]

[0002] Patent Document 1 proposes a cleaning blade in which the contact portion that comes into contact with the member to be cleaned contains polyurethane rubber polymerized from at least 30 mol% to 50 mol% of a polyol component containing 1,4-butanediol relative to the total polyol component, and a polyisocyanate component, wherein the ratio of 100% modulus (M100 [MPa]) to rebound modulus (Re [%]) (M100 / Re) is 0.25 or more, and the rebound modulus (Re [%]) is 25% or more. Patent Document 2 proposes a toner comprising "a binder resin, a colorant, a wax, and resin fine particles, wherein the resin fine particles are made of a resin that is incompatible with the binder resin, and have a glass transition temperature of 100 to 220°C and an average particle size of 0.05 to 1 μm." [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2014-235423 [Patent Document 1] Japanese Patent Publication No. 2007-108591 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The object of the present invention is to provide an image forming apparatus that includes an electrophotographic photoreceptor, a charging device for charging the surface of the electrophotographic photoreceptor, an electrostatic image forming device for forming an electrostatic image on the surface of the charged electrophotographic photoreceptor, a developing device containing a developer containing toner and developing the electrostatic image formed on the surface of the electrophotographic photoreceptor with the developer to form a toner image, a cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photoreceptor, and a transfer device for transferring the toner image to the surface of a recording medium, wherein the toner is toner particles containing a binder resin and resin particles and an external additive, and compared to a case where the rebound modulus A and 100% modulus B of the member constituting the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor, and the resin particle content C relative to the total toner particles satisfy the following formula (C1) or the following formula (C2), the slippage of removed material from the cleaning blade when continuously forming an image is suppressed. Formula (C1): 0.045 > resin particle content C / rebound modulus A, or resin particle content C / rebound modulus A > 1.160 Formula (C2): 0.29 > resin particle content C / 100% modulus B, or resin particle content C / 100% modulus B > 4.53 [Means for solving the problem]

[0005] The above problems will be solved by the following means: <1> 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 develops the electrostatic charge image formed on the surface of the electrophotographic photoreceptor with the developer to form a toner image, A cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photoreceptor, A transfer device for transferring the toner image onto the surface of a recording medium, Equipped with, The toner comprises toner particles containing a binder resin and resin particles, and an external additive. An image forming apparatus in which the rebound modulus A and 100% modulus B of the member constituting the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor, and the content C of the resin particles relative to the total toner particles satisfy the following formulas (1) and (2). Equation (1): 0.045 ≤ the content of the resin particles C / the rebound modulus A ≤ 1.160 Equation (2): 0.29 ≤ resin particle content C / 100% modulus B ≤ 4.53 <2> The content C of the resin particles relative to the total toner particles is 2% by mass or more and 30% by mass or less. <1> The image forming apparatus described above. <3> The number-average particle size of the aforementioned resin particles is between 60 nm and 300 nm. <1> or <2> The image forming apparatus described above. <4> The aforementioned resin particles are crosslinked resin particles. <1> ~ <3> An image forming apparatus as described in any one of the following. <5> The aforementioned crosslinked resin particles are styrene (meth)acrylic resin particles. <4> The image forming apparatus described above. <6> In the dynamic viscoelasticity measurement of the resin particles during a temperature increase of 2°C / min, the storage modulus G' in the range of 23°C to 80°C was 1 × 10⁻¹⁰. 5 Pa or more 5×10 7 It is less than or equal to Pa. <1> ~ <5> An image forming apparatus as described in any one of the following. <7> In a dynamic viscoelasticity measurement of the component obtained by removing the resin particles from the toner particles when the temperature is increased by 2°C / min, the storage modulus G' in the range of 23°C to 50°C is 1 × 10⁻⁶. 8 The Pa value is greater than or equal to the storage modulus G' of 1 × 10⁻⁶. 5 The temperature at which it reaches below Pa is between 65°C and 90°C. <6> The image forming apparatus described above. <8> 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 0.5 or more and 2.0 or less, the value of D50(150) - D1(150) is less than 1.5, the value of D50(90) - D1(90) is less than 0.5, the image forming apparatus according to any one of <1> to <7>. <9> 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, the image forming apparatus according to any one of <1> to <8>. <10> The contact portion of the cleaning blade that contacts the electrophotographic photoreceptor contains a polyurethane rubber obtained by polymerizing at least a polyol component containing 30 mol% or more and 50 mol% or less of 1,4 - butanediol with respect to the total polyol component and a polyisocyanate component, the resilience modulus A is 25% or more and 60% or less, and the 100% modulus B is 5 MPa or more and 10 MPa or less, and is composed of a member, the image forming apparatus according to any one of <1> to <9>. <11> An electrophotographic photoreceptor, a developing device that stores a developer containing toner and develops an electrostatic charge image formed on the surface of the electrophotographic photoreceptor with the developer to form a toner image, a cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photoreceptor, and is provided with the toner has toner particles containing a binder resin and resin particles and an external additive, the resilience modulus A and 100% modulus B of the member constituting the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor, and the content ratio C of the resin particles with respect to the entire toner particles satisfy the following formula (1) and the following formula (2), and a process cartridge that detaches from the image forming apparatus. Formula (1): 0.045 ≤ the content ratio C of the resin particles / the resilience modulus A ≤ 1.160 Formula (2): 0.29 ≤ the content ratio C of the resin particles / the 100% modulus B ≤ 4.53

Advantages of the Invention

[0006] <1> The present invention provides an image forming apparatus comprising an electrophotographic 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 containing toner and developing the electrostatic image formed on the surface of the electrophotographic photoreceptor with the developer to form a toner image, a cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photoreceptor, and a transfer device for transferring the toner image to the surface of a recording medium, wherein the toner comprises toner particles containing a binder resin and resin particles and an external additive, and compared to a case where the rebound modulus A and 100% modulus B of the member constituting the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor, and the resin particle content C relative to the total toner particles satisfy the following formula (C1) or the following formula (C2), an image forming apparatus is provided in which the slippage of removed material from the cleaning blade when continuously forming an image is suppressed. Formula (C1): 0.045 > resin particle content C / rebound modulus A, or resin particle content C / rebound modulus A > 1.160 Formula (C2): 0.29 > resin particle content C / 100% modulus B, or resin particle content C / 100% modulus B > 4.53

[0007] <2> According to the invention, an image forming apparatus is provided in which the slippage of removed material from the cleaning blade during continuous image formation is suppressed, compared to cases where the resin particle content C relative to the total toner particles is less than 2% by mass or more than 30% by mass. <3> According to the invention, an image forming apparatus is provided in which the slippage of removed material from the cleaning blade during continuous image formation is suppressed compared to cases where the number-average particle size of the resin particles is less than 60 nm or greater than 300 nm. <4> According to the invention, compared to the case where the resin particles are non-crosslinked resin particles, an image forming apparatus is provided in which the slippage of removed material from the cleaning blade during continuous image formation is suppressed. <5> According to the invention, compared to the case where the resin particles are polyester resin particles, an image forming apparatus is provided in which the slippage of removed material from the cleaning blade during continuous image formation is suppressed.

[0008] <6> According to the invention, in the dynamic viscoelasticity measurement of resin particles when the temperature is increased by 2°C / min, the storage modulus G' in the range of 30°C to 80°C is 1 × 10⁻⁶ 5 Less than Pa, or 5 × 10 7 Compared to cases where the Pa value exceeds a certain level, an image forming apparatus is provided in which the slippage of removed material from the cleaning blade during continuous image formation is suppressed. <7> According to the invention, in the dynamic viscoelasticity measurement of the component obtained by removing resin particles from toner particles when the temperature is raised by 2°C / min, the storage modulus G' in the range of 30°C to 50°C is 1 × 10⁻⁶. 8 If Pa is less than 10⁻¹⁰, or if the storage modulus G' is 1 × 10⁻¹⁰ 5 The present invention provides an image forming apparatus that suppresses the passage of removed material from the cleaning blade when continuously forming images, compared to cases where the temperature reaching below Pa is less than 65°C or more than 90°C. <8> According to the invention relating to the present invention, in the dynamic viscoelasticity measurement of 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), If at least one of D1(90), D50(90), D1(150), and D50(150) is less than 0.5 or greater than 2.0, If the value of D50(150)-D1(150) is 1.5 or greater, or Compared to the case where the value of D50(90)-D1(90) is 0.5 or greater, an image forming apparatus is provided in which the slippage of removed material from the cleaning blade during continuous image formation is suppressed. <9> According to the invention, an image forming apparatus is provided in which the amount of external additives that slips through the cleaning blade when an image is continuously formed is suppressed, compared to cases where the amount of external additives is less than 0.01% by mass or more than 5% by mass relative to the toner particles. <10> According to the present invention, compared to cases where the rebound modulus A of the member constituting the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is less than 25% or more than 60%, or where the 100% modulus B is less than 5 MPa or more than 10 MPa, an image forming apparatus is provided in which the slippage of removed material from the cleaning blade is suppressed when continuously forming an image, even when the cleaning apparatus has a cleaning blade in which the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is made of polyurethane rubber obtained by polymerizing at least a polyol component containing 1,4-butanediol and a polyisocyanate component.

[0009] <11> According to the present invention, an image forming apparatus is provided that includes an electrophotographic photoreceptor, a charging device for charging the surface of the electrophotographic photoreceptor, an electrostatic image forming device for forming an electrostatic image on the surface of the charged electrophotographic photoreceptor, a developing device that contains a developer containing toner and develops the electrostatic image formed on the surface of the electrophotographic photoreceptor with the developer to form a toner image, and a cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photoreceptor, wherein the toner is a process cartridge having toner particles containing a binder resin and resin particles and an external additive, and compared to the case where the rebound modulus A and 100% modulus B of the members constituting the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor, and the resin particle content C relative to the total toner particles satisfy the above formula (C1) or the above formula (C2), the amount of material removed from the cleaning blade when an image is continuously formed is suppressed. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing an example of an image forming apparatus according to this embodiment. [Figure 2] This is an enlarged view showing the position where the cleaning blade and the photoreceptor come into contact in the image forming apparatus shown in Figure 1. [Figure 3] This is a schematic diagram showing an example of a cleaning blade in this embodiment. [Figure 4] This is a schematic diagram showing another example of the cleaning blade in this embodiment. [Figure 5] This is a schematic diagram showing another example of the cleaning blade in this embodiment. [Modes for carrying out the invention]

[0011] The following describes an example embodiment 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.

[0012] 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.

[0013] <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 containing toner and developing the electrostatic image formed on the surface of the electrophotographic photoreceptor with the developer to form a toner image, a cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photoreceptor, and a transfer device for transferring the toner image to the surface of a recording medium. The toner comprises toner particles containing a binder resin and resin particles and an external additive, and the rebound modulus A and 100% modulus B of the member constituting the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor, and the content C of resin particles relative to the total toner particles satisfy the following formulas (1) and (2). Equation (1): 0.045 ≤ resin particle content C / rebound modulus A ≤ 1.160 Equation (2): 0.29 ≤ resin particle content C / 100% modulus B ≤ 4.53

[0014] The image forming apparatus according to this embodiment, with the above configuration, suppresses the passage of removed material from the cleaning blade when images are formed continuously. The reason for this is presumed to be as follows.

[0015] The image forming apparatus comprises an electrophotographic 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 developing the electrostatic image formed on the surface of the electrophotographic photoreceptor with the developer to form a toner image, a cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photoreceptor, and a transfer device for transferring the toner image to the surface of a recording medium, wherein the toner consists of toner particles containing a binder resin and resin particles and an external additive, in which case when images were formed continuously, material removed from the cleaning blade sometimes slipped through. This is because toner containing binder resin and resin particles, along with an external additive (hereinafter also referred to as "specific toner"), has both low-elasticity and high-elasticity areas. For example, when forming an image under high-temperature and high-humidity conditions (e.g., 28°C, 85%RH), in the case of an image forming apparatus equipped with a conventional cleaning blade, the cleaning blade tends to bend excessively. As a result, the external additive in the toner is more likely to become embedded in the low-elasticity areas of the toner due to the linear pressure from the cleaning blade. Consequently, it becomes difficult for the external additive to be supplied between the cleaning blade and the electrophotographic photoreceptor, and the wear of the cleaning blade progresses easily. Therefore, when images are formed continuously, the cleaning performance of the cleaning blade tends to decrease, and material removed from the cleaning blade is more likely to slip through. Furthermore, when forming images under low temperature and low humidity conditions (e.g., 10°C, 15%RH), conventional image forming apparatuses equipped with cleaning blades tend to release a large amount of external additives from the toner, which may not be completely removed by the cleaning blades. As a result, when forming images continuously, it becomes easier for the removed material to slip past the cleaning blades.

[0016] In the image forming apparatus according to this embodiment, the rebound modulus A and 100% modulus B of the member constituting the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor, and the content C of resin particles relative to the total toner particles, satisfy the above formulas (1) and (2). By satisfying equations (1) and (2) above, the flexibility of the cleaning blade becomes appropriate, and stress is more easily transmitted from the cleaning blade to the material to be removed. Furthermore, by satisfying equations (1) and (2) above, an appropriate amount of external additive is more easily supplied between the cleaning blade and the electrophotographic photoreceptor. As a result, wear of the cleaning blade is suppressed, and the material to be removed is more efficiently removed by the cleaning blade.

[0017] From the above, it is presumed that the image forming apparatus according to this embodiment suppresses the passage of removed material from the cleaning blade when images are formed continuously, thanks to the above configuration.

[0018] In the image forming apparatus according to this embodiment, the rebound modulus A and 100% modulus B of the member constituting the contact portion of the cleaning blade that contacts the photoreceptor, and the content C of resin particles (i.e., "internally added resin particles" described later) relative to the total toner particles satisfy the following formulas (1) and (2). Equation (1): 0.045 ≤ resin particle content C / rebound modulus A ≤ 1.160 Equation (2): 0.29 ≤ resin particle content C / 100% modulus B ≤ 4.53

[0019] From the viewpoint of further suppressing the passage of removed material from the cleaning blade when images are formed continuously, the rebound modulus A, 100% modulus B, and content C of resin particles (i.e., "internally added resin particles" described below) preferably satisfy the following formulas (1-2) and (2-2), more preferably satisfy the following formulas (1-3) and (2-3), and even more preferably satisfy the following formulas (1-4) and (2-4).

[0020] Equation (1-2): 0.1 ≤ resin particle content C / rebound modulus A ≤ 1.160 Equation (2-2): 0.6 ≤ resin particle content C / 100% modulus B ≤ 2.8

[0021] Equation (1-3): 0.15 ≤ resin particle content C / rebound modulus A ≤ 1.1 Equation (2-3): 0.8 ≤ resin particle content C / 100% modulus B ≤ 2.6

[0022] Equation (1-4): 0.2 ≤ resin particle content C / rebound modulus A ≤ 1.0 Equation (2-4): 1.0 ≤ resin particle content C / 100% modulus B ≤ 2.4

[0023] Here, the rebound modulus A and the 100% modulus B are values ​​measured by the method described in the [Examples] section below.

[0024] Herein, the image forming apparatus according to this embodiment is applicable to well-known image forming apparatuses such as: a direct transfer type apparatus that directly transfers an electrostatic image developing toner image formed on the surface of a photoreceptor to a recording medium; an intermediate transfer type apparatus that first transfers an electrostatic image developing toner image formed on the surface of a photoreceptor to the surface of an intermediate transfer body, and secondarily transfers the electrostatic image developing 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 remove static charge after the transfer of the electrostatic image developing toner image and before charging.

[0025] In the case of an intermediate transfer method apparatus, the transfer apparatus may include, for example, an intermediate transfer body on which an electrostatic image developing toner image is transferred; a primary transfer apparatus that first transfers the electrostatic image developing 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 electrostatic image developing toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

[0026] The image forming apparatus according to this embodiment may, for example, have a cartridge structure (process cartridge) that is detachable from the image forming apparatus, with at least a portion including a photoreceptor, a developing device, and a cleaning device.

[0027] The following is 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.

[0028] 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.

[0029] 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. The image forming apparatus 10 also has a control device 36 that controls the operation of each device (each part). The unit including the photoreceptor 12, charging device 15, electrostatic image forming device 16, developing device 18, transfer device 31, and cleaning device 22 corresponds to the image forming unit.

[0030] 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.

[0031] The details of each device (part) of the image forming apparatus 10 will be described below.

[0032] [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.

[0033] [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.

[0034] 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 type roller chargers, scorotron chargers or corotron chargers utilizing corona discharge, and other known chargers.

[0035] [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.

[0036] Examples of electrostatic image forming apparatus 16 include optical equipment having a light source that exposes an image-like object with light such as semiconductor laser light, LED light, or liquid crystal shutter light.

[0037] [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 an electrostatic image developer having a specific toner. The specific toner is stored, for example, in a charged state within the developing device 18.

[0038] 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 a specific 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.

[0039] 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 magnet built in.

[0040] 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, and is driven and controlled by the control device 36 to apply a developing voltage to the developing member 18A. The developing member 18A, to which the developing voltage has been applied, is charged to a developing potential corresponding to the developing voltage. The developing member 18A, charged to the developing potential, then holds, for example, the developer contained in the developing device 18 on its surface and supplies a specific toner contained in the developer from inside the developing device 18 to the surface of the photoreceptor 12. On the surface of the photoreceptor 12 to which the specific toner has been supplied, the formed electrostatic charge image is developed as a specific toner image.

[0041] [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 a specific toner image formed on the surface of the photoreceptor 12 to a 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 in shape 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.

[0042] Examples of the transfer member 20 include contact-type transfer chargers using belts, rollers, films, rubber cleaning blades, etc., as well as non-contact type transfer chargers that are known themselves, such as scorotron transfer chargers or corotron transfer chargers that utilize corona discharge.

[0043] The transfer device 31 (including the power supply 30) is electrically connected to, for example, a control device 36 provided in the image forming apparatus 10, and is driven and controlled by the control device 36 to apply a transfer voltage to the transfer member 20. The transfer member 20, to which the transfer voltage has been applied, is charged to a transfer potential corresponding to the transfer voltage.

[0044] When a transfer voltage opposite in polarity to that of the specific toner constituting the specific toner image formed on the photoreceptor 12 is applied to the transfer member 20 from the power supply 30 of the transfer member 20, for example, 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 specific toner constituting the specific image on the photoreceptor 12 to move from the photoreceptor 12 to the transfer member 20 side by electrostatic force.

[0045] The recording medium 30A is housed in a storage unit (not shown), for example, and is transported from this storage unit along a transport path 34 by a plurality of transport members (not shown) to the transfer region 32A, which is the region 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 specific toner image on the photoreceptor 12 is transferred to the recording medium 30A by a transfer electric field formed in the region, for example, when a transfer voltage is applied to the transfer member 20. That is, for example, the specific toner image is transferred onto the recording medium 30A by the movement of the specific toner from the surface of the photoreceptor 12 to the recording medium 30A. The specific toner image on the photoreceptor 12 is then transferred onto the recording medium 30A by the transfer electric field.

[0046] [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 a specific 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.

[0047] 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.

[0048] Now, with reference to Figure 2, the cleaning device 22 will be described. FIG. 2 is a schematic configuration diagram showing the installation mode of the cleaning blade 220 in the cleaning device 22 shown in FIG. 1. As shown in FIG. 2, the tip of the cleaning blade 220 faces the direction opposite to the rotation direction (arrow direction) of the photoreceptor 12 and is in contact with the surface of the photoreceptor 12 in this state.

[0049] The angle θ between the cleaning blade 220 and the photoreceptor 12 is preferably set to 5° or more and 35° or less, and more preferably set to 10° or more and 25° or less. Further, the pressing pressure N of the cleaning blade 220 against the photoreceptor 12 is 0.6 gf / mm 2 or more and 6.0 gf / mm 2 or less. Here, specifically, as shown in FIG. 2, the angle θ refers to the angle of the angle formed by the tangent line (the dashed line in FIG. 2) at the contact portion between the tip of the cleaning blade 220 and the photoreceptor 12 and the non-deformed portion of the cleaning blade 220. Also, the pressing pressure N refers to the pressure (gf / mm 2 ) that presses the cleaning blade 220 toward the center of the photoreceptor 12 at the position where the cleaning blade 220 contacts the photoreceptor 12 as shown in FIG. 2.

[0050] Note that the cleaning blade 220 in the present embodiment is a plate-like object having elasticity.

[0051] A support member (not shown in FIG. 2) is joined to the surface side of the cleaning blade 220 opposite to the surface that contacts the photoreceptor 12, and the cleaning blade 220 is supported by this support member. By this support member, the cleaning blade 220 is pressed against the photoreceptor 12 with the above pressing pressure. Examples of the support member include metal materials such as aluminum and stainless steel. Note that an adhesive layer or the like for bonding the two may be provided between the support member and the cleaning blade 220. The cleaning device may include known members other than the cleaning blade 220 and the support member that supports it.

[0052] The cleaning blade will be described in detail below, but the symbols will be omitted in the following description of the cleaning blade.

[0053] The cleaning blade consists of a contact portion that comes into contact with the electrophotographic photoreceptor (hereinafter also referred to as the "contact member"), and may have a two-layer structure with a first layer that comes into contact with the surface of the photoreceptor and a second layer as a back layer on the back of the first layer, or it may have a three-layer or more structure. Alternatively, only the corners of the portion that comes into contact with the photoreceptor may consist of the contact member, with the surrounding area made of another material.

[0054] Next, the configuration of the cleaning blade will be explained in more detail using a diagram. First, the parts of the cleaning blade will be explained using Figure 3. In the following, as shown in Figure 3, the cleaning blade has a contact portion (contact angle portion) 3A that contacts the driven photoreceptor 12 and cleans the surface of the photoreceptor 12, a tip surface 3B that forms one side of the contact angle portion 3A and faces upstream in the direction of the drive (direction of arrow A), a ventral surface 3C that forms one side of the contact angle portion 3A and faces downstream in the direction of the drive (direction of arrow A), and a back surface 3D that shares one side with the tip surface 3B and faces the ventral surface 3C. Furthermore, the direction parallel to the contact angle 3A is referred to as the depth direction, the direction from the contact angle 3A toward the side where the tip surface 3B is formed is referred to as the thickness direction, and the direction from the contact angle 3A toward the side where the ventral surface 3C is formed is referred to as the width direction.

[0055] The cleaning blade 342A shown in Figure 3 is made entirely of a single material, including the portion (contact angle) 3A that contacts the photoreceptor 12; in other words, it consists only of a contact member.

[0056] The cleaning blade may also have a two-layer configuration, as shown in Figure 4, comprising a first layer 3421B formed over the entire surface of the ventral side 3C and consisting of a contact member, including a portion (contact angle) 3A that contacts the photoreceptor 12, and a second layer 3422B as a back layer formed on the back surface 3D side of the first layer and consisting of a different material from the contact member.

[0057] Furthermore, the cleaning blade may be configured as shown in Figure 5, including a contact member (edge ​​member) 3421C made of a contact member, which has a shape in which a cylinder cut into quarters extends in the depth direction and the right-angle portion of this shape forms the contact angle 3A, and a back member 3422C made of a different material from the contact member, which covers the back surface 3D side in the thickness direction and the side opposite to the front end surface 3B in the width direction of the contact member 3421C, that is, which constitutes the part other than the contact member 3421C. Although Figure 5 shows an example of a contact member having the shape of a cylinder cut into quarters, it is not limited to this. The contact member may also have shapes such as an elliptical cylinder cut into quarters, a square prism, or a rectangular prism.

[0058] Preferably, the cleaning blade has a contact portion (hereinafter also simply referred to as the "contact portion") that comes into contact with the photoreceptor, and is made of a polyurethane rubber polymerized with at least 30 mol% to 50 mol% of a polyol component containing 1,4-butanediol relative to the total polyol component, and a polyisocyanate component, and has a rebound modulus A of 25% to 60% and a 100% modulus B of 5 MPa to 10 MPa (hereinafter also referred to as the "specific contact member").

[0059] By using the above configuration for the cleaning blade, the image forming apparatus tends to suppress the passage of removed material from the cleaning blade when forming images more continuously. The reason for this is presumed to be as follows. By setting the rebound modulus A to 25% to 60% and the 100% modulus B to 5 MPa to 10 MPa, stress is more easily transmitted from the cleaning blade to the removed material. Furthermore, by including polyurethane rubber polymerized with at least a polyol component containing 30 mol% to 50 mol% of 1,4-butanediol relative to the total polyol component, and a polyisocyanate component, it becomes easier to achieve a rebound modulus A of 25% to 60% and a 100% modulus B of 5 MPa to 10 MPa. Therefore, it is presumed that this will result in an image forming apparatus that suppresses the passage of removed material from the cleaning blade when forming images more continuously.

[0060] From the viewpoint of providing an image forming apparatus that suppresses the slippage of removed material from the cleaning blade when forming images more continuously, the rebound modulus A is more preferably 30% to 55%, and even more preferably 35% to 50%. From the viewpoint of providing an image forming apparatus that suppresses the passage of removed material from the cleaning blade when forming images more continuously, it is more preferable that the 100% modulus B is 6 MPa or more and 9 MPa or less, and even more preferable that it is 7 MPa or more and 8 MPa or less.

[0061] Here, the rebound modulus A and the 100% modulus B are values ​​measured by the method described in the [Examples] section below.

[0062] The weight-average molecular weight of the specific contact member (polyurethane rubber member) is preferably between 1000 and 4000, and more preferably between 1500 and 3500.

[0063] • 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.

[0064] It is desirable for polyurethane rubber to have 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. The materials that make up the hard segment (hard segment material) include low molecular weight polyol components among polyol components, and resins having functional groups that can react with the isocyanate groups of polyisocyanates. On the other hand, the materials that make up the soft segment (soft segment material) include high molecular weight polyol components among polyol components.

[0065] • Polyol components The polyol component includes both high molecular weight polyols and low molecular weight polyols.

[0066] The polymeric polyol component is a polyol with a number-average molecular weight of 500 or more (preferably 500 to 5000). Examples of polymeric 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 reaction of low molecular weight polyols and alkyl carbonates, polycaprolactone polyols, and polyether polyols. Examples of commercially available polymeric polyols include Praxel 205 and Praxel 240 manufactured by Daicel Chemical Industries, Ltd.

[0067] • Polyol components The polyol component includes both high molecular weight polyols and low molecular weight polyols.

[0068] The polymeric polyol component is a polyol with a number-average molecular weight of 500 or more (preferably 500 to 5000). Examples of polymeric 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 reaction of low molecular weight polyols and alkyl carbonates, polycaprolactone polyols, and polyether polyols. Examples of commercially available polymeric polyols include Praxel 205 and Praxel 240 manufactured by Daicel Chemical Industries, Ltd.

[0069] Here, the number-average molecular weight is the value measured by gel permeation chromatography (GPC). The same applies hereafter.

[0070] These polymeric polyols may be used individually or in combination of two or more types.

[0071] The polymerization ratio of the high-molecular-weight polyol component is preferably 30 mol% to 70 mol% relative to the total polymerization component of the polyurethane rubber, and more preferably 40 mol% to 60 mol%.

[0072] Low molecular weight polyol components are polyols with a molecular weight (number average molecular weight) of less than 500. Low molecular weight polyols are materials that function as chain length extenders and crosslinking agents.

[0073] As the low molecular weight polyol component, 1,4-butanediol is preferably used. The proportion of 1,4-butanediol is preferably 30 mol% to 50 mol% (preferably 30 mol% to 40 mol%) relative to the total polyol components (high molecular weight polyol + low molecular weight polyol). The proportion of 1,4-butanediol to the total low molecular weight polyol component is preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol%. In other words, it is most preferable to use 1,4-butanediol as the total low molecular weight polyol component.

[0074] In addition to 1,4-butanediol, other low molecular weight polyol components include diols (bifunctional), triols (trifunctional), and tetraols (tetrafunctional), which are well known as chain length extenders and crosslinking agents. These polyols other than 1,4-butanediol may be used individually or in combination of two or more.

[0075] The polymerization ratio of the low molecular weight polyol component is preferably 30 mol% to 50 mol% relative to the total polymerization components of the polyurethane rubber, and more preferably 30 mol% to 40 mol%.

[0076] • 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-dimethylphenyl-4,4-diisocyanate (TODI).

[0077] As polyisocyanate components, 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), and hexamethylene diisocyanate (HDI) are more preferable.

[0078] These polyisocyanate components may be used individually or in combination of two or more.

[0079] 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.

[0080] • 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.

[0081] 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.

[0082] Examples of commercially available polybutadiene resins containing two or more hydroxyl groups include R-45HT, manufactured by Idemitsu Kosan Co., Ltd.

[0083] 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 preferably has a structure (flexible skeleton) in its main chain that allows for high main chain mobility. 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 be within the range of 15000 ± 5000 mPa·s, and more preferably within the range of 15000 ± 3000 mPa·s. Examples of commercially available epoxy resins having these characteristics include EPLICON EXA-4850-150 from DIC.

[0084] 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.

[0085] • Manufacturing method of polyurethane rubber Polyurethane rubber is manufactured using common polyurethane manufacturing methods such as the prepolymer method and 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 manufacturing method is not limiting. 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.

[0086] Examples of catalysts used in the production of polyurethane rubber include amine compounds such as tertiary amines, quaternary ammonium salts, and organometallic compounds such as organotin compounds. Examples of the above-mentioned tertiary amines include trialkylamines such as triethylamine, tetraalkyldiamines such as N,N,N',N'-tetramethyl-1,3-butanediamine, amino alcohols such as dimethylethanolamine, ethoxylated amines, ethoxylated diamines, esteramines such as bis(diethylethanolamine)adipate, cyclohexylamine derivatives such as triethylenediamine (TEDA) and N,N-dimethylcyclohexylamine, morpholine derivatives such as N-methylmorpholine and N-(2-hydroxypropyl)-dimethylmorpholine, and piperazine derivatives such as N,N'-diethyl-2-methylpiperazine and N,N'-bis-(2-hydroxypropyl)-2-methylpiperazine.

[0087] Examples of the above-mentioned quaternary ammonium salts include 2-hydroxypropyltrimethylammonium octylate, 1,5-diazabicyclo[4.3.0]nonene-5(DBN)octylate, 1,8-diazabicyclo[5.4.0]undecene-7(DBU)octylate, DBU oleate, DBU-p-toluenesulfonate, DBU formate, and 2-hydroxypropyltrimethylammonium formate.

[0088] Examples of the above organotin compounds include dialkyltin compounds such as dibutyltin dilaurate and dibutyltin di(2-ethylhexoate), as well as stannous 2-ethylcaproate and stannous oleate.

[0089] Among these catalysts, triethylenediamine (TEDA), a tertiary ammonium salt, is preferred in terms of hydrolysis resistance, while quaternary ammonium salts are preferred in terms of processability. Among quaternary ammonium salts, 1,5-diazabicyclo[4.3.0]nonene-5(DBN)·octylate, 1,8-diazabicyclo[5.4.0]undecene-7(DBU)-octylate, and DBU-formate are preferred due to their high reaction activity.

[0090] The content of the above catalyst is preferably in the range of 0.0005% by mass or more and 0.03% by mass or less of the total polyurethane rubber constituting the specific contact member, and particularly preferably 0.001% by mass or more and 0.01% by mass or less. These can be used individually or in combination of two or more types.

[0091] Next, we will explain the composition of the non-contact member when the cleaning blade is composed of different materials for the contact member and the area other than the contact member (non-contact member), as shown in the configurations of Figure 4 and Figure 5.

[0092] 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, propylene 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.

[0093] -Manufacturing of cleaning blades- In the case of a cleaning blade consisting only of the contact members shown in Figure 3, the cleaning blade is manufactured by the molding method of the contact members described above.

[0094] Furthermore, in the case of a cleaning blade with a multi-layer structure, such as the two-layer structure shown in Figure 4, the cleaning blade is manufactured by bonding the first layer as a contact member and the second layer (or multiple layers in the case of a three-layer or more layer structure) to each other. Suitable methods for bonding 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.

[0095] Furthermore, in the case of a configuration having a contact member (edge ​​member) and a non-contact member (back member) as shown in Figure 5, a first mold is prepared, which has a cavity (a region into which the composition for forming the contact member is poured) corresponding to the shape of a semi-cylindrical form when two contact members 3421C are overlapped on their ventral sides 3C, as shown in Figure 5, and a second mold is prepared, which has a cavity corresponding to the shape when two contact members 3421C and two non-contact members 3422C are overlapped on their ventral sides 3C. The composition for forming the contact member is poured into the cavity of the first mold and hardened to form a first molded product in the shape of two overlapping contact members 3421C. Next, after removing the first mold, the second mold is set up so that the first molded product is placed inside the cavity of the second mold. After that, the composition for forming the non-contact member is poured into the cavity of the second mold so as to cover the first molded product and hardened to form a second molded product in the shape of two overlapping contact members 3421C and two non-contact members 3422C with their ventral sides 3C together. Next, the formed second molded product is cut in the middle, that is, in the part that becomes the ventral surface 3C, so that the semi-cylindrical contact member is divided in the middle and cut into quarters, resulting in a cylindrical shape. Further cutting to the specified dimensions yields the cleaning blade shown in Figure 5.

[0096] [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 a specific 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.

[0097] Examples of static elimination devices 24 include devices having a light source such as a tungsten lamp that emits white light or a light-emitting diode (LED) that emits red light.

[0098] [Fusing device] The fixing device 26 is, for example, located downstream of the transfer area 32A in the transport direction of the transport path 34 of the recording medium 30A. The fixing device 26 includes a fixing member 26A and a pressurizing member 26B positioned in contact with the fixing member 26A, and fixes the specific toner image transferred onto the recording medium 30A at the contact point 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 specific toner image transferred onto the recording medium 30A to the recording medium 30A by heat and pressure.

[0099] Examples of the fixing device 26 include known fixing devices such as hot roller fixing devices and oven fixing devices. 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.

[0100] Here, the recording medium 30A, which has been transported along the transport path 34 and has the specific toner image transferred to it 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 specific toner image on the recording medium 30A is fixed.

[0101] The recording medium 30A, on which an image has been formed by fixing a specific toner image, is discharged to the outside of the image forming apparatus 10 by a plurality of transport members (not shown in the figure). The photoreceptor 12 is then discharged by the static elimination device 24 and then recharged to a charging potential by the charging device 15.

[0102] [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.

[0103] 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 using a developer containing a specific toner. This forms a specific toner image on the surface of the photoreceptor 12. In the transfer device 31, a specific toner image formed on the surface of the photoreceptor 12 is transferred to the recording medium 30A. The specific toner image transferred to the recording medium 30A is fixed by the fuser device 26. Meanwhile, the surface of the photoreceptor 12 after transferring the specific toner image is cleaned by the cleaning blade 220 in the cleaning device 22, and then static electricity is removed by the static elimination device 24.

[0104] [Developer] The developer according to this embodiment contains at least a specific toner. The developer according to this embodiment may be a one-component developer containing only the specific toner, or it may be a two-component developer mixed with the specific toner and a carrier.

[0105] <Toner> The toner (specific toner) according to this embodiment comprises toner particles containing a binder resin and resin particles, and an external additive.

[0106] (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. In the following explanation, the resin particles added to the toner particles will be referred to as "added resin particles" to distinguish them from the resin particles used as binders in the manufacture of the toner particles.

[0107] -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.

[0108] 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 resins refer to materials that, in thermal analysis measurements using differential scanning calorimetry (DSC), exhibit only a stepwise endothermic change rather than a clear endothermic peak, are solid at room temperature, and undergo thermoplasticization at temperatures above their 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 with a full width at half maximum (FWHM) exceeding 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.

[0109] 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.

[0110] Amorphous polyester resin Examples of amorphous polyester resins include condensation polymers of polycarboxylic acids and polyhydric alcohols. The amorphous polyester resin may be a commercially available product or a synthesized one.

[0111] 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., with 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 cross-linked 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.

[0112] 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.

[0113] 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, it is determined by the "extracorporeal glass transition onset temperature" described in the method for determining the glass transition temperature in JIS K 7121-1987 "Method for Measuring the Transition Temperature of Plastics".

[0114] 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 to 100, and more preferably 2 to 60. 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 analyzer, a Tosoh TSKgel SuperHM-M (15cm) 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.

[0115] 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.

[0116] 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.

[0117] • Crystalline polyester resin 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.

[0118] 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.

[0119] Examples of polyhydric alcohols include aliphatic diols (for example, linear aliphatic diols with 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.

[0120] Here, the polyhydric alcohol is preferably composed of 80 mol% or more of aliphatic diols, and more preferably 90 mol% or more.

[0121] 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".

[0122] The weight-average molecular weight (Mw) of crystalline polyester resin is between 6,000 and 35,000. The bottom is preferable.

[0123] Crystalline polyester resins can be obtained, for example, by well-known manufacturing methods, similar to amorphous polyesters.

[0124] 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.

[0125] -Internal resin particles- The internally added resin particles exhibited a storage modulus G' of 1 × 10 in the range of 23°C to 80°C in dynamic viscoelasticity measurements during a 2°C / min temperature increase. 5 Pa or more 5×10 7 Resin particles with a Pa of 0 or less are preferred. The storage modulus G' of the internally added resin particles in the range of 23°C to 80°C is 1 × 10⁻⁶ 5 Pa or more 2×10 7 It is preferable that the Pa is less than or equal to 1 × 10 5 Pa or more 1×10 7 It is more preferable that the value be less than or equal to Pa.

[0126] Internally added resin particles whose storage modulus G' in the range of 23°C to 80°C are particles with high elasticity even in the range of 23°C to 80°C. Therefore, by including internally added resin particles with a storage modulus G' in the range above in the toner particles, the toner particles have the property that the adhesion of external additive particles does not change much with respect to temperature and humidity. As a result, it becomes easier to maintain the amount of external additive released as designed, even in low temperature and low humidity environments, and high temperature and high humidity environments, and the leakage of removed material from the cleaning blade when continuously forming images is further suppressed.

[0127] 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 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 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

[0128] 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.

[0129] By using cross-linked resin particles as the internally added resin particles, it becomes easier to obtain internally added resin particles whose storage modulus G' in the range of 23°C to 80°C falls within the aforementioned range. Therefore, the passage of removed material from the cleaning blade during continuous image formation is further suppressed.

[0130] Examples of crosslinked resin particles include crosslinked resin particles crosslinked by ionic bonds (ionic crosslinked resin particles) and crosslinked resin particles crosslinked by covalent bonds (covalently crosslinked resin particles). Among these, crosslinked resin particles crosslinked by covalent bonds are preferred.

[0131] 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.

[0132] Among the resins mentioned above, 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.

[0133] Because the crosslinked resin particles are styrene (meth)acrylic resin particles, the internally added resin particles are more likely to have a storage modulus G' in the range of 23°C to 80°C. Therefore, the passage of removed material from the cleaning blade is further suppressed when images are formed continuously.

[0134] Examples of styrene (meth)acrylic resins include resins obtained by polymerizing the following styrene monomers and (meth)acrylic acid monomers by radical polymerization.

[0135] 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.

[0136] 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.

[0137] 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 hydroxyl dimethacrylate 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 acetonedicarboxylate, divinyl glutarate, divinyl 3,3'-thiodipropionate, divinyl trans-aconitate, trivinyl trans-aconitate, divinyl adipicate, 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.

[0138] Furthermore, if the internally added resin particles are polymers 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 contained 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.

[0139] 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 become more susceptible to the elasticity of the internally added resin particles. Furthermore, the dispersibility within the toner particles also increases. As a result, the toner particles have an appropriate hardness. On the other hand, when the number-average particle size of the internally added resin particles is 300 nm or smaller, excessive hardness of the toner particles is suppressed. Therefore, by setting the average particle size of the internal resin particles within the above range, the amount of external additive released from the toner becomes within an appropriate range, making it easier for the external additive to be supplied appropriately between the cleaning blade and the electrophotographic photoreceptor. As a result, the leakage of removed material from the cleaning blade is further suppressed when images are formed continuously.

[0140] 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 image 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.

[0141] 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 toner particles are prevented from becoming excessively hard. Therefore, by setting the internal resin particle content C within the above range, the amount of external additive released from the toner becomes within an appropriate range, making it easier for the external additive to be supplied appropriately between the cleaning blade and the electrophotographic photoreceptor. As a result, the leakage of removed material from the cleaning blade is further suppressed when images are formed continuously.

[0142] -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.

[0143] 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.

[0144] The colorant content is preferably 1% to 30% by mass, and more preferably 3% to 15% by mass, relative to the total toner particles.

[0145] -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, the release agents are not limited to these.

[0146] 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".

[0147] 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.

[0148] -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.

[0149] -Relationships of composition in 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 greater and -0.12 or less.

[0150] 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, 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 compared to when it is greater than the above range. 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).

[0151] 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.

[0152] The solubility parameter SP value (S) of the internally added resin particles is preferably 9.00 or more and 9.15 or less, more preferably 9.03 or more and 9.12 or less, and even more preferably 9.06 or more and 9.10 or less.

[0153] 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 / cm)) are given. 3 ) 1 / 2 The calculation is performed using the Okitsu method. The Okitsu method is described in detail in "Journal of the Adhesion Society of Japan, Vol. 29, No. 5 (1993)".

[0154] • Viscoelasticity of components excluding internally added resin particles (excluded components) The storage modulus G' of the component obtained by removing the internal resin particles from the toner particles is 1 × 10 in the range of 23°C to 50°C. 8 The Pa value is greater than or equal to the storage modulus G' of 1 × 10⁻⁶. 5 It is preferable that the temperature at which Pa falls below 65°C is between 65°C and 90°C. Hereafter, the components remaining after removing the internally added resin particles from the toner particles will also be called "excluded components," and their storage modulus G' is 1 × 10⁻⁶ 5 The temperature at which the storage modulus G' reaches less than Pa is also called the "temperature at which the specific modulus is reached." Exclusion components whose storage modulus G' satisfies the above conditions have a high modulus at low temperatures and a low modulus between 65°C and 90°C. Here, if the storage modulus G' of an exclusion component satisfies the above conditions, then the storage modulus G' becomes 1 × 10⁻⁶ 5 Compared to cases where the temperature below Pa exceeds 90°C, the toner particles tend to become more viscoelastic, resulting in an appropriate amount of external additive release from the toner. This makes it easier for the external additive to be supplied appropriately between the cleaning blade and the electrophotographic photoreceptor. As a result, the leakage of removed material from the cleaning blade during continuous image formation is further suppressed.

[0155] The storage modulus G' of the excluded component at temperatures between 23°C and 50°C is 1 × 10⁻⁶ 8 Preferably Pa or higher, 1 × 10 8 Pa or more 1×10 9It is more preferable that it be less than or equal to Pa, 2 × 10 8 Pa or more 6×10 8 It is even more preferable that it be Pa or less.

[0156] 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.

[0157] 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.) Measuring jig: 8mm parallel plate Gap: Adjusted to 3mm Frequency: 1Hz

[0158] -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 toner particles with a core-shell structure preferably consist of 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.

[0159] When toner particles have a core-shell structure, it is preferable that internal resin particles are contained in both the core particles and the shell layer. By containing internal resin particles in both the core particles and the shell layer, the internal resin particles are contained in both the surface and central regions of the toner particles, further reducing the difference in gloss levels.

[0160] The volume-average particle size (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0161] 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 the ISOTON-II (manufactured by Beckman Coulter). For measurement, add 0.5 mg to 50 mg of the sample to be measured in 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. Add this to 100 ml to 150 ml of electrolyte. The electrolyte containing the suspended sample was dispersed in an ultrasonic disperser for 1 minute, and then subjected to Coulter Multiscale. Using the ZAR II system, the particle size distribution of particles with a diameter of 2 μm to 60 μm will be measured using an aperture with a diameter of 100 μm. The number of particles to be sampled will be 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 (D84v / D16v) 1 / 2 The GSDp index is (D84p / D16p) 1 / 2 It is calculated as follows.

[0162] The average circularity of the toner particles is preferably 0.94 to 1.00, and more preferably 0.95 to 0.98.

[0163] 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 still image of the particles is captured by instantaneous strobe flashing. 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.

[0164] (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, and the like.

[0165] The surface of the inorganic particles used as an external additive should preferably be subjected to a hydrophobic treatment. The hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, 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.

[0166] 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).

[0167] 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 externally added excipients is 0.01% by mass or more, the amount of free excipients is prevented from becoming excessively low. On the other hand, when the amount of externally added excipients is 5% by mass or less, the amount of free excipients is prevented from becoming excessively high. Therefore, the external additive is more easily supplied in an appropriate amount between the cleaning blade and the electrophotographic photoreceptor. As a result, the leakage of removed material from the cleaning blade is further suppressed when images are formed continuously.

[0168] (Toner characteristics) - Viscoelastic properties 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 viscoelastic properties at high temperatures with high strain and low temperatures with low strain. Consequently, it is possible to achieve the intended amount of external additive release in both high and low temperature environments. This suppresses the passage of removed material from the cleaning blade when continuously forming images.

[0169] 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, the leakage of removed material from the cleaning blade when continuously forming an image is suppressed.

[0170] The D50(150)-D1(150) value in the toner is less than 1.5, preferably 1.2 or less, and more preferably 1.0 or less. Having the D50(150)-D1(150) value within this range suppresses the leakage of material removed from the cleaning blade when continuously forming images. Furthermore, there is no particular limit to the lower limit of the value of D50(150)-D1(150).

[0171] 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. Having the D50(90)-D1(90) value within this range suppresses the leakage of material removed from the cleaning blade when continuously forming images. Furthermore, there is no particular limit to the lower limit of the value of D50(90)-D1(90).

[0172] 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, dynamic viscoelasticity measurements are performed using a rheometer under the following conditions, and the loss tangent tanδ at temperatures of 90°C or 150°C and strain amounts 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.) Measuring jig: 8mm parallel plate Gap: Adjusted to 3mm Frequency: 1Hz

[0173] (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.

[0174] 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.

[0175] 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 the binder are dispersed, and an internal resin particle dispersion in which internal resin particles will become the 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).

[0176] 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.

[0177] -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.

[0178] Here, the resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium with a surfactant.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] The resin particle content in the resin particle dispersion is preferably, for example, 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0184] Furthermore, colorant particle dispersions and mold release agent particle dispersions are prepared in the same manner as resin particle dispersions. In other words, the volume average particle size, dispersion medium, dispersion method, and particle content of the resin particle dispersions are the same for colorant particles dispersed in colorant particle dispersions and mold release agent particles dispersed in mold release agent particle dispersions.

[0185] Preparation of internal resin particle dispersion As for the preparation method of the internally added resin particle dispersion, known methods such as emulsion polymerization, melt kneading using a Banbury mixer or kneader, suspension polymerization, and spray drying can be applied, but emulsion polymerization is preferred.

[0186] From the viewpoint of keeping the storage modulus G' and loss tangent tanδ of the internally added resin particles within a preferred 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.

[0187] 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 an 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.

[0188] -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, etc. 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.

[0189] It is preferable to use styrene-based monomers and (meth)acrylic acid-based monomers as monomers. The crosslinking agents described above are applicable.

[0190] 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. 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.

[0191] The emulsified solution may contain a chain transfer agent. There are no particular restrictions on the chain transfer agent, but compounds having 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.

[0192] 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 total emulsion is 0.5% by mass or more and 3% by mass or less.

[0193] -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'.

[0194] -Second emulsion polymerization process- 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 monomers. For example, increasing the time spent adding the emulsion containing monomers makes it easier to obtain resin particles with a high storage modulus G'. The time spent adding the emulsion containing monomers 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.

[0195] -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.

[0196] Specifically, for example, a coagulant 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 of -10°C) to agglomerate the particles dispersed in the mixed dispersion and form agglomerated 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.

[0197] 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 suitable temperatures for the mixed dispersion include a range of 5°C to 40°C. Also, in this step, the dispersion state of the internally added resin particles in the obtained toner particles may be controlled by adjusting the stirring speed after adding the flocculant. For example, by increasing the stirring speed after adding the flocculant, the dispersibility of the internally added resin particles becomes good.

[0198] Examples of the flocculant include surfactants having a reverse polarity to the surfactants used as dispersants added to the mixed dispersion liquid, inorganic metal salts, and metal complexes with a valence of 2 or more. In particular, when a metal complex is used as the flocculant, the amount of surfactant used is reduced and the charging characteristics are improved. An additive that forms a complex or a similar bond with the metal ions of the flocculant may be used as needed. As this additive, a chelating agent is preferably used.

[0199] Examples of the inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, and inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. As the chelating agent, a water-soluble chelating agent may be used. Examples of the chelating agent include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid, iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA). The addition amount of the chelating agent is preferably, for example, 0.01 parts by mass or more and 5.0 parts by mass or less, more preferably 0.1 parts by mass or more and less than 3.0 parts by mass with respect to 100 parts by mass of the resin particles.

[0200] -Fusion / Unification Step- Next, the aggregated particle dispersion in which the aggregated particles are dispersed is heated to, for example, a temperature equal to or higher than the glass transition temperature of the resin particles (for example, a temperature 10 to 30 °C higher than the glass transition temperature of the resin particles) to fuse and unite the aggregated particles to form toner particles.

[0201] Through the above steps, toner particles are obtained. After obtaining the aggregated particle dispersion liquid in which the aggregated particles are dispersed, the aggregated particle dispersion liquid, the resin particle dispersion liquid in which the resin particles are dispersed, and the internally added resin particle dispersion liquid in which the internally added resin particles are dispersed are further mixed, and the resin particles and the internally added resin particles are further aggregated so as to adhere to the surface of the aggregated particles to form second aggregated particles; and heating the second aggregated particle dispersion liquid in which the second aggregated particles are dispersed to fuse and unite the second aggregated particles to form toner particles having a core / shell structure. Toner particles may be produced through these steps.

[0202] In the step of forming the second aggregated particles, the addition of the resin particle dispersion liquid and the internally added resin particle dispersion liquid and the adhesion of the resin particles and the internally added resin particles to the surface of the aggregated particles may be repeated a plurality of times. By repeating a plurality of times, toner particles in which the internally added resin particles are evenly contained in both the surface region and the central region of the toner particles can be obtained.

[0203] Here, after the fusion and unification step, the toner particles formed in the solution are dried through known cleaning steps, solid-liquid separation steps, and drying steps to obtain toner particles in a dried state. In the cleaning step, it is preferable to perform substitution cleaning sufficiently with ion-exchanged water from the viewpoint of chargeability. Also, in the solid-liquid separation step, although there is no particular limitation, it is preferable to perform suction filtration, pressure filtration, etc. from the viewpoint of productivity. Also, there is no particular limitation on the drying method either, but it is preferable to perform freeze drying, airflow drying, fluid drying, vibration type fluid drying, etc. from the viewpoint of productivity.

[0204] Then, the toner according to the present embodiment is produced, for example, by adding and mixing an external additive to the obtained toner particles in a dried state. The mixing may be performed, for example, by a V blender, a Henschel mixer, a Lodige mixer, etc. Further, if necessary, coarse particles of the toner may be removed using a vibrating sieve, an air classifier, etc.

[0205] <Electrostatic charge image developer> The electrostatic charge image developer according to the present embodiment includes at least the toner according to the present embodiment. The electrostatic image 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.

[0206] 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.

[0207] Examples of magnetic powders include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0208] 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 oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0209] 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.

[0210] 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. [Examples]

[0211] 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.

[0212] [Preparation of internally added 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 was added, followed by dispersion and emulsification in a flask to prepare an emulsion. Subsequently, 1.3 parts of an anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical Company) was dissolved in 90 parts of ion-exchanged water, 1 part of the above emulsion was added thereto, and further, 10 parts of ion-exchanged water in which 5.4 parts of ammonium persulfate was dissolved was added. Thereafter, the remaining emulsion was added over 180 minutes. After nitrogen substitution in the flask, the solution in the flask was heated to 65 °C in an oil bath while stirring, and emulsion polymerization was continuously carried out for 500 minutes as it was. Thereafter, an internal additive resin particle dispersion liquid 1 having a solid content adjusted to 24.5% by mass was obtained.

[0213] <Preparation of internal additive resin particle dispersion liquids 2 to 10 and C1 to C2> Internal additive resin particle dispersion liquids 2 to 10 and C1 to C2 were obtained in the same manner as internal additive resin particle dispersion liquid 1, except that the addition amounts of styrene, n-butyl acrylate, acrylic acid, β-carboxyethyl acrylate, the total addition amount of anionic surfactant, the addition amount of butanediol diacrylate (crosslinking agent in the table), the addition amount of ammonium peroxide, the temperature heated in an oil bath (polymerization temperature in the table), the time for adding the remaining emulsion (addition time in the table), and the time for continuously carrying out emulsion polymerization after heating (holding time in the table) were as shown in Table 1.

[0214]

Table 1

[0215] Regarding the resin particles contained in the obtained internal additive resin particle dispersion liquids and comparative resin particle dispersion liquids, the minimum value (''G’(small)'' in the table) and maximum value (''G’(large)'' in the table) of the storage elastic modulus G’ at 23 °C or higher and 80 °C or lower, the number average particle diameter, and the SP value (S) were determined by the above-described method, and the results are shown in Table 2.

[0216]

Table 2

[0217] [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 placed in a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectification column. The temperature was raised to 190°C over 1 hour, and 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 generated water, and the dehydration condensation reaction was continued at 240°C for 3 hours, after which the reactants were cooled.

[0218] The reactants were 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 mass% 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 rotor speed was 60 Hz and the pressure was 5 kg / cm². 2 The Cavitron CD1010 was operated under the specified conditions 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 to obtain amorphous resin particle dispersion 1. The obtained amorphous polyester resin had an SP value (R) of 9.43.

[0219] <Preparation of amorphous resin particle dispersion 2> Styrene: 72 units n-butyl acrylate: 27 parts • β-carboxyethyl acrylate: 1.3 parts Dodecanethiol: Part 2 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 deionized 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 deionized 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 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. Deionized water was added to this resin particle dispersion to adjust the solid content to 31.4% by mass to obtain amorphous resin particle dispersion 2. The obtained amorphous styrene-acrylic resin had an SP value (R) of 9.14.

[0220] <Preparation of crystalline resin particle dispersion> • 1,10-Dodecanedioic acid: 225 parts • 1,6-Hexanediol: 143 parts The above materials were placed in a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectification column. The temperature was raised to 160°C over 1 hour, and 0.8 parts by mass of dibutyltin oxide were added. The temperature was raised to 180°C over 6 hours while distilling off the generated water, 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 reaction mixture was then cooled. After cooling, solid-liquid separation was performed, and the solid was dried to obtain a crystalline polyester resin.

[0221] • Crystalline polyester resin: 100 units • Methyl ethyl ketone: 40 parts • Isopropyl alcohol: 30 parts • 10% ammonia aqueous 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. The resin was dissolved while stirring at 100 rpm in a water-circulating constant-temperature bath, maintaining the temperature at 80°C. Subsequently, the water-circulating constant-temperature bath was set to 50°C, and 400 parts of ion-exchanged water, kept at 50°C, were 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 flask was heated in a 60°C water bath while rotating, and the solvent was removed by reducing the pressure to 7 kPa while taking care to prevent bumping. The volume-average particle size D50v of the resin particles in this dispersion was 185 nm. Subsequently, deionized water was added to obtain a dispersion of crystalline resin particles with a solid content concentration of 22.1% by mass.

[0222] <Preparation of colorant dispersion> • Cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15:3 (copper phthalocyanine)): 98 parts • Anionic surfactant (TaycaPower, manufactured by Teika Co., Ltd.): 2 parts • Ion-exchanged water: 420 units The above ingredients 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.

[0223] <Preparation of mold release agent dispersion> • Synthetic wax (manufactured by Nippon Seiro Co., Ltd., FNP92, melting point Tw: 92℃): 50 units • Anionic surfactant (TaycaPower, manufactured by Teika Co., Ltd.): 1 part • Ion-exchanged water: 200 bottles The above materials were mixed and heated to 130°C, dispersed using a homogenizer (IKA Ultra-Turrax T50), and then dispersed again using a Manton-Gorin high-pressure homogenizer (Gorin), 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.

[0224] <Toner 1> ·Amorphous resin particle dispersion 1: 169 parts ·Internal 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, whose liquid temperature was 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.

[0225] 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 1 part 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.

[0226] 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.

[0227] 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.

[0228] <Toner 2-11, Toner C1-C2> Toners 2-11 and C1-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.

[0229] <Toner 12> Toner 12 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 3, and the amount of internally added resin particle dispersion was used so that the content of resin particles relative to the total toner particles was the value shown in Table 3.

[0230] <Toner 13-14> Toners 13 and 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.

[0231] <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.

[0232] <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.

[0233] <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 3.

[0234] <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 3, 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 3.

[0235] <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.

[0236] <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.

[0237] <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 the value shown in Table 3, and the pH at the time of fusion of aggregated particles was changed from 8.0 to 9.5.

[0238] <Toner 22> Toner 22 was obtained in the same manner as toner 1, except that 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 3, and the pH at the time of fusion of aggregated particles was changed from 8.0 to 6.0.

[0239] <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 3 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 3, 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 3.

[0240] <Toner 28, 29, C6, C7> Toners 28 to 31 were obtained in the same manner as toner 1, except that dimethyl silicone oil-treated silica particles (RY200, manufactured by Nippon Aerosil Co., Ltd.) were added to 100 parts of the obtained toner particles in the following amounts and mixed using a Henschel mixer to obtain toner. Toner C6: 0.005 units Toner 28: 0.01 parts Toner 29: 5.00 copies Toner C7: 5.10 units

[0241] <Toner C3> ·Amorphous resin particle dispersion 1: 169 parts ·Internal 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, whose liquid temperature has been adjusted to 30°C, are placed in a 3L cylindrical stainless steel container, and a homogenizer (IKA Ultra-Turrax T50) is used to apply a shearing force at 4000 rpm. Then, the mixture was dispersed and mixed 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.

[0242] 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.

[0243] 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.

[0244] 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.

[0245] <Toner C4> ·Amorphous resin particle dispersion 1: 169 parts ·Internal 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, whose liquid temperature was 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.

[0246] 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.

[0247] The aggregated particles were sorted while checking their size and morphology using an optical microscope and a multi-sizer 3. The pH was then adjusted to 7.8 using a 5% sodium hydroxide solution and maintained 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 C4.

[0248] 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 C4.

[0249] <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, whose liquid temperature was 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.

[0250] 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.

[0251] 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 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.

[0252] 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 C5.

[0253] Table 3 shows 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, Table 3 shows the results obtained by the aforementioned method for determining the storage modulus G' (indicated as "G'(Pa)" in the table) and the temperature at which the specific modulus of the excluded components is reached (indicated as "Temperature Reached (°C)" in the table) in the range of 23°C to 50°C. Furthermore, Table 3 shows the results obtained by calculating the values ​​of D1(90), D50(90), D1(150), D50(150), D50(150)-D1(150) ("Difference (150)" in the table), the value of D50(90)-D1(90) ("Difference (90)" in the table), the storage modulus G' in the range of 23°C to 50°C ("G'(Pa)" in the table), and the difference (SP value (S) - SP value (R)) ("SP value difference" in the table) using the method described above for the obtained toner. Furthermore, in Table 3, "External Additive Content (%)" refers to the amount of external additive relative to the total toner particles.

[0254] <Preparation of Developers 1-29 and Developers C1-C7> Eight parts of the obtained toner were mixed with 100 parts of the carrier described below to obtain developers 1-29 and C-C7.

[0255] -Creating a Career- • Ferrite particles (average particle size 50 μm) 100 units • Toluene 14 parts • Styrene / methyl methacrylate copolymer (copolymerization ratio 15 / 85) 3 parts • Carbon black 0.2 parts The above components, excluding ferrite particles, were dispersed in a sand mill to prepare a dispersion. This dispersion was then placed together with ferrite particles in a vacuum-degassed kneader and dried under reduced pressure while stirring to obtain a carrier.

[0256] [Table 3-1]

[0257] [Table 3-2]

[0258] [Table 3-3]

[0259] [Preparation of Cleaning Blade A1] First, the flat plate member that would serve as the contact member was formed as follows. First, a polyether polyol consisting of PTMG (polytetramethylene ether glycol, trade name "PTG-2000SN (manufactured by Hodogaya Chemical Co., Ltd.)") as the high-molecular-weight polyol component was obtained. This polyether polyol was reacted with MDI (4,4'-diphenylmethane diisocyanate, trade name "Millionate MT (manufactured by Nippon Polyurethane Industry Co., Ltd.)") as the isocyanate component to obtain a prepolymer. To this prepolymer, trimethylolethane was added along with 1,4-butanediol (manufactured by Mitsubishi Gas Chemical Co., Ltd., molecular weight = 90.12) as the low-molecular-weight polyol component to prepare composition A1 for forming flat members. The molar ratio (mol%) of each component to the total polymer component was as shown in Table 4. However, the molar ratio of trimethylolethane was 1 mol%.

[0260] Next, composition A1 for forming flat plate members was poured into a centrifugal molding machine with the mold adjusted to 140°C, and allowed to cure for 1 hour to form flat plate members that would become contact members.

[0261] Meanwhile, diphenylmethane-4,4-diisocyanate was mixed with dehydrated polytetramethylene ether glycol and reacted at 120°C for 15 minutes. Composition B1 for forming flat members was then prepared by adding 1,4-butadiol and trimethylolpropane to the resulting prepolymer.

[0262] Next, after forming the contact plate members, the flat plate member forming composition B1 was poured into the centrifugal molding machine and cured to form the non-contact plate members, thereby obtaining a two-layer flat plate member in which the contact plate member and the non-contact plate member were laminated.

[0263] Then, the two-layered flat plate member was heated at 110°C for 24 hours, cooled, and cut to dimensions of 8 mm in length and 2 mm in thickness, to obtain a cleaning blade with a contact member thickness of 0.5 mm and a non-contact member thickness of 1.5 mm.

[0264] [Cleaning blade A-2, Cleaning blades B-1~H] A cleaning blade was obtained in the same manner as cleaning blade A-1, except that the types and amounts (molar ratios) of the high molecular weight polyol component, low molecular weight polyol component, and polyisocyanate component were changed according to the contact member formulation shown in Table 4.

[0265] The rebound modulus A and 100% modulus B were measured as follows. The measurement results are shown in Table 4.

[0266] -Rebound modulus A- The rebound modulus A was determined using a Lübke rebound modulus tester at 23°C in accordance with JIS K6255 (1996).

[0267] -100% Modulus B- The 100% modulus B was determined in accordance with JIS-K6251, using a dumbbell-shaped No. 3 test specimen, measured at a tensile speed of 500 mm / min, and calculated from the stress at 100% strain. The measuring device used was a Strograph AE elastomer manufactured by Toyo Seiki Co., Ltd. The measurements were performed in a 23°C environment.

[0268] [Table 4]

[0269] The following details the abbreviations and other terms shown in Table 4. • Ether (PTMG): Polytetramethylene ether glycol, trade name "PTG-2000SN (manufactured by Hodogaya Chemical Co., Ltd.)", number average molecular weight = 2000) • Ester (adipate): Product name "Nipporan 4040 (manufactured by Nippon Polyurethane Industry Co., Ltd.)", number average molecular weight = 2000 • Ester (caprolactone): Product name "PLACCEL220 (manufactured by Daicel Corporation)", number average molecular weight = 2000 • 1,4-BDO: 1,4-butanediol (manufactured by Mitsubishi Gas Chemical Company, Inc.), molecular weight = 90.12 • MDI: 4,4'-diphenylmethane diisocyanate, trade name "Millionate MT (manufactured by Nippon Polyurethane Industries Co., Ltd.)" • TDI: 2,6-toluene diisocyanate, trade name "Cosmonate T-80 (manufactured by Mitsui Chemicals, Inc.)"

[0270] <Examples 1-28, Comparative Examples 1-4> The developer and cleaning blade were installed in the image forming machine "Apeos C7070 manufactured by Fujifilm Business Innovation Co., Ltd." in the combinations shown in Table 5. Then, the following evaluations were performed using the resulting image forming apparatus.

[0271] <Rating> (Linear muscle evaluation) In a high-temperature, high-humidity environment (28°C, RH 85%), 100,000 images with an image density of 1% were printed. Then, the environment was moved to a low-temperature, low-humidity environment (10°C, RH 15%), and 100,000 images with an image density of 1% were printed again. Finally, one image with a 50% full-surface halftone was printed, and the presence or absence of streaks (white streaks and colored streaks) on the halftone was evaluated. The evaluation criteria were as follows: A grade of C or higher was considered a passing grade. A: Neither white nor colored vein streaks have developed. B: White and colored streaks are present in some parts of the image (less than 3 lines). C: Some white and colored muscle fibers are present in the image (less than 5). D: White and colored muscle fibers are present in more than half of the image. E: White and colored streaks appear across the entire image.

[0272] [Table 5]

[0273] From the above results, it can be seen that the image forming apparatus of this embodiment suppresses the passage of removed material from the cleaning blade when continuously forming images, compared to the image forming apparatus of the comparative example. [Explanation of symbols]

[0274] 10 Image forming apparatus 12 Photoreceptor 14 Charged members 15. Charging device 16 Electrostatic image forming device 18. Developing device 20 Transfer Member 22 Cleaning device 24 Static eliminator 26 Fixing device 30A recording medium 31 Transfer device 36 Control device

Claims

1. 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 develops the electrostatic charge image formed on the surface of the electrophotographic photoreceptor with the developer to form a toner image, A cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photoreceptor, A transfer device for transferring the toner image onto the surface of a recording medium, Equipped with, The toner comprises toner particles containing a binder resin and resin particles, and an external additive. An image forming apparatus in which the rebound modulus A (%) and 100% modulus B (MPa) of the member constituting the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor, and the content C (mass%) of the resin particles relative to the total toner particles satisfy the following formulas (1) and (2). Equation (1): 0.045 ≤ resin particle content C (mass%) / rebound modulus A (%) ≤ 1.160 Equation (2): 0.29 ≤ resin particle content C (mass%) / 100% modulus B (MPa) ≤ 4.53

2. The image forming apparatus according to claim 1, wherein the content C (mass%) of the resin particles relative to the total toner particles is 2% by mass or more and 30% by mass or less.

3. The image forming apparatus according to claim 1 or claim 2, wherein the number-average particle size of the resin particles is 60 nm or more and 300 nm or less.

4. The image forming apparatus according to any one of claims 1 to 3, wherein the resin particles are crosslinked resin particles.

5. The image forming apparatus according to claim 4, wherein the crosslinked resin particles are styrene (meth)acrylic resin particles.

6. In the dynamic viscoelasticity measurement of the resin particles during a temperature increase of 2°C / min, the storage modulus G' in the range of 23°C to 80°C was 1 × 10⁻⁶. ５ Pa or more 5×10 ７ An image forming apparatus according to any one of claims 1 to 5, wherein the pressure is Pa or less.

7. In a dynamic viscoelasticity measurement of the component obtained by removing the resin particles from the toner particles during a temperature increase of 2°C / min, the storage modulus G' in the range of 23°C to 50°C is 1 × 10⁻¹⁰. ８ The pressure is greater than or equal to Pa, and the storage modulus G' is 1 × 10⁻⁶. ５ The image forming apparatus according to claim 6, wherein the temperature at which Pa falls below 65°C is 65°C or higher and 90°C or lower.

8. 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 7, wherein the value of D50(90)-D1(90) is less than 0.

5.

9. The content of the external additive is 0.01% by mass or more and 5% by mass or less relative to the toner particles. An image forming apparatus according to any one of claims 1 to 8.

10. The image forming apparatus according to any one of claims 1 to 9, wherein the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is made of a material containing polyurethane rubber polymerized from at least 30 mol% to 50 mol% of a polyol component with respect to the total polyol component and a polyisocyanate component, the rebound modulus A (%) being 25% to 60%, and the 100% modulus B (MPa) being 5 MPa to 10 MPa.

11. Electrophotographic photoreceptor, A developing apparatus that contains a developer containing toner, and develops the electrostatic charge image formed on the surface of the electrophotographic photoreceptor with the developer to form a toner image, A cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photoreceptor, Equipped with, 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 rebound modulus A (%) and 100% modulus B (MPa) of the member constituting the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor, and the content C (mass%) of the resin particles relative to the total toner particles, satisfy the following formulas (1) and (2). Equation (1): 0.045 ≤ resin particle content C (mass%) / rebound modulus A (%) ≤ 1.160 Equation (2): 0.29 ≤ resin particle content C (mass%) / 100% modulus B (MPa) ≤ 4.53

Images