Image forming apparatus and process cartridge

Abstract

To provide an image forming apparatus that achieves both reduction of wear of a cleaning blade and reduction of wear of an inorganic protective layer of an electrophotographic photoreceptor.SOLUTION: An image forming apparatus is such that: the content of resin particles in the entire toner particle is 2 mass% or more and 30 mass% or less; the sum of the component ratios of oxygen, hydrogen, and the Group 13 element to the entire elements constituting an inorganic protective layer is 0.95 or more, and the element component ratio R of oxygen to the Group 13 element (oxygen / Group 13 element) is 0.8 or more and 1.9 or less; and the ratio of the content ratio W of the resin particles to the element component ratio R of oxygen to the Group 13 element (oxygen / Group 13 element) (W / R) satisfies 1.05≤W / R≤3.75.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] An image is formed by electrophotography, for example, by charging the surface of an electrophotographic photosensitive member, forming an electrostatic image on the surface of the electrophotographic photosensitive member in accordance with image information, developing the electrostatic image with a developer containing a toner for developing an electrostatic image to form a toner image for developing an electrostatic image, and transferring and fixing the toner image for developing an electrostatic image to the surface of a recording medium.

[0003] Here, Patent Document 1 describes a photosensitive drum comprising: "a conductive substrate; a photoconductive layer containing at least amorphous silicon on the conductive substrate; and a surface protective layer containing amorphous silicon and / or amorphous carbon; and the element ratio of the surface protective layer is expressed by the composition formula: Si 1-X C x When Si 1-X C x The document discloses a cleaning method using an amorphous silicon photosensitive member satisfying (0.93≦x≦0.98), not having a drum heater for adjusting the temperature of the amorphous silicon photosensitive member, corona charging the surface of the amorphous silicon photosensitive member, forming an electrostatic latent image by exposure, developing the electrostatic latent image with toner particles having a binder resin and a colorant, and a toner having a cubic or rectangular parallelepiped particle shape and containing strontium titanate powder as an external additive with a number-average particle size of 30 nm or more and 300 nm or less, transferring the developed toner to a transfer material with or without intermediate transfer, and removing transfer residual toner remaining on the amorphous silicon photosensitive member after transfer from the amorphous silicon photosensitive member by cleaning with a blade that is in pressure contact with a roller-shaped member that contacts the amorphous silicon photosensitive member.

[0004] Furthermore, Patent Document 2 discloses an image forming apparatus comprising: "an electrophotographic photosensitive member having an organic photosensitive layer and an inorganic protective layer in this order on a conductive substrate; charging means for charging the surface of the electrophotographic photosensitive member; electrostatic latent image forming means for forming an electrostatic latent image on the charged surface of the electrophotographic photosensitive member; developing means for storing a developer containing a toner having toner particles and metal soap particles and developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with the developer to form a toner image; transfer means for transferring the toner image formed on the surface of the electrophotographic photosensitive member to the surface of a recording medium; and cleaning means for contacting the cleaning blade with the surface of the electrophotographic photosensitive member to clean the surface of the electrophotographic photosensitive member after the toner image has been transferred by the transfer means." Patent Document 2 discloses that the inorganic protective layer is a layer containing a Group 13 element and oxygen.

[0005] Furthermore, Patent Document 3 discloses "a toner comprising toner core particles containing at least a polyester resin, a layer of styrene-acrylic resin fine particles A formed on the surface of the toner core particles, and acrylic resin fine particles B present inside the layer, wherein the storage modulus A1 (Pa) at 100°C and the storage modulus A2 (Pa) at 200°C of the styrene-acrylic resin fine particles A satisfy the following relational expression (1), and the storage modulus B1 (Pa) at 100°C and the storage modulus B2 (Pa) at 200°C of the acrylic resin fine particles B satisfy the following relational expression (2)." 1×10 4 ≦A1≦1×10 6 , 10≦A2≦500...Equation (1) 1×10 6 ≦B1≦1×10 8 , 100≦B2≦1000...Equation (2) [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-243202 [Patent Document 2] Japanese Patent Application Publication No. 2017-062343 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-195679 Summary of the Invention [Problem to be solved by the invention]

[0007] As shown in Patent Document 2, an image forming apparatus (hereinafter also referred to as a "specific image forming apparatus") is known which includes "an electrophotographic photosensitive member having, as its outermost surface layer, an inorganic protective layer containing oxygen, hydrogen, and a Group 13 element; a charging device which contacts and charges the surface of the electrophotographic photosensitive member; an electrostatic latent image forming device which forms an electrostatic latent image on the surface of the charged electrophotographic photosensitive member; a developing device which contains a developer containing toner and develops the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with the developer to form a toner image; a cleaning device which has a cleaning blade which cleans the surface of the electrophotographic photosensitive member; and a transfer device which transfers the toner image to the surface of a recording medium."

[0008] Furthermore, as shown in Patent Document 2, "toner having toner particles containing a binder resin and resin particles, and an external additive (hereinafter also referred to as "specific toner")" is also known.

[0009] Conventionally, when a specific toner is used in a specific image forming apparatus, the cleaning blade may be worn down and the inorganic protective layer of the electrophotographic photosensitive member may be worn down.

[0010] Therefore, an object of the present invention is to provide an image forming apparatus in which a specific toner is used, in which both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member are achieved, compared to when the content of resin particles is less than 2% by mass or more than 30% by mass of the entire toner particles, the sum of the composition ratios of oxygen, hydrogen, and Group 13 elements to the total amount of elements constituting the inorganic protective layer is less than 0.95, or the element composition ratio R of oxygen to the Group 13 elements (oxygen / Group 13 elements) is less than 0.8 or more than 0.9, or the ratio (W / R) of the element composition ratio R of oxygen to the Group 13 elements (oxygen / Group 13 elements) is less than 1.05 or more than 37.5. [Means for solving the problem]

[0011] Specific means for solving the problems include the following aspects. <1> an electrophotographic photoreceptor having an inorganic protective layer containing oxygen, hydrogen, and a Group 13 element as an outermost surface layer; a charging device that contacts and charges the surface of the electrophotographic photosensitive member; an electrostatic image forming device for forming an electrostatic image on the charged surface of the electrophotographic photosensitive member; a developing device that contains a developer containing a toner and develops an electrostatic image formed on the surface of the electrophotographic photosensitive member with the developer to form a toner image; a cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photosensitive member; a transfer device that transfers the toner image onto a surface of a recording medium; Equipped with the toner comprises toner particles containing a binder resin and resin particles, and an external additive, and the content of the resin particles relative to the total amount of the toner particles is 2% by mass or more and 30% by mass or less; the inorganic protective layer has a sum of the constituent ratios of the oxygen, the hydrogen, and the Group 13 element with respect to the total amount of elements constituting the inorganic protective layer of 0.95 or more, and an elemental constituent ratio R of the oxygen to the Group 13 element (oxygen / Group 13 element) of 0.8 or more and 1.9 or less; a ratio (W / R) of the content W of the resin particles to the elemental composition ratio R of oxygen to the Group 13 elements (oxygen / Group 13 elements) satisfies 1.05≦W / R≦37.5; Image forming device. <2> a ratio (W / R) of the content W of the resin particles to the elemental composition ratio R of oxygen to the Group 13 elements (oxygen / Group 13 elements) satisfies 6.99≦W / R≦12.23; <1> 2. The image forming apparatus according to claim 1 . <3> The number average particle size of the resin particles is 60 nm or more and 300 nm or less. <1> or <2> 2. The image forming apparatus according to claim 1 . <4> In the dynamic viscoelasticity measurement of the resin particles at a temperature rise of 2°C / min, the storage modulus G' in the range of 23°C to 80°C is 1 x 10 5 Pa or more 5×10 7 Pa or less, <1> ~ <3> 10. The image forming apparatus according to claim 1, wherein <5> In a dynamic viscoelasticity measurement of the components excluding the resin particles from the toner particles at a temperature rise of 2°C / min, the storage modulus G' in the range of 23°C to 50°C is 1 x 10 8 Pa or more, and the storage modulus G' is 1 x 10 5 The temperature at which the temperature reaches less than 65°C or more and 90°C or less. <4> 2. The image forming apparatus according to claim 1 . <6> In the dynamic viscoelasticity measurement of the toner, when the loss tangent tanδ at a temperature of 90°C and a distortion of 1% is D1(90), the loss tangent tanδ at a temperature of 90°C and a distortion of 50% is D50(90), the loss tangent tanδ at a temperature of 150°C and a distortion of 1% is D1(150), and the loss tangent tanδ at a temperature of 150°C and a distortion 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. <1> ~ <5> 10. The image forming apparatus according to claim 1, wherein <7> The resin particles are crosslinked resin particles. <1> ~ <6> 10. The image forming apparatus according to claim 1, wherein <8> The crosslinked resin particles are styrene (meth)acrylic resin particles. <7> 2. The image forming apparatus according to claim 1 . <9> the toner contains silica particles as the external additive; <1> ~ <8> 10. The image forming apparatus according to claim 1, wherein <10> the toner contains titanium oxide particles together with the silica particles as the external additive; <9> 2. The image forming apparatus according to claim 1 . <11> 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. <1> ~ <10> 10. The image forming apparatus according to claim 1, wherein <12> In the inorganic protective layer, the Group 13 element is gallium. <1> ~ <11> 10. The image forming apparatus according to claim 1, wherein <13> The inorganic protective layer has a water contact angle of 95° or more and 100° or less. <1> ~ <12> 10. The image forming apparatus according to claim 1, wherein <14> a contact portion of the cleaning blade that comes into contact with the electrophotographic photosensitive member is made of a member having a 100% modulus at 23°C of 4 MPa or more and 18 MPa or less; <1> ~ <13> 10. The image forming apparatus according to claim 1, wherein <15> an electrophotographic photoreceptor having an inorganic protective layer containing oxygen, hydrogen, and a Group 13 element as an outermost surface layer; a developing device that contains a developer containing a toner and develops an electrostatic latent image formed on the surface of the electrophotographic photosensitive member with the developer to form a toner image; a cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photosensitive member; Equipped with the toner comprises toner particles containing a binder resin and resin particles, and an external additive, and the content of the resin particles is 2% by mass or more and 30% by mass or less with respect to the total amount of the toner particles; the inorganic protective layer has a sum of the constituent ratios of the oxygen, the hydrogen, and the Group 13 element with respect to the total amount of elements constituting the inorganic protective layer of 0.95 or more, and an elemental constituent ratio R of the oxygen to the Group 13 element (oxygen / Group 13 element) of 0.8 or more and 1.9 or less; a ratio (W / R) of the content W of the resin particles to the elemental composition ratio R of oxygen to the Group 13 element (oxygen / Group 13 element) satisfies 1.05≦W / R≦37.5, A process cartridge that is detachably attached to an image forming apparatus. [Effects of the Invention]

[0012] <1> According to the invention relating to (1), in a specific image forming apparatus using a specific toner, an image forming apparatus is provided in which both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member are achieved, compared to when the resin particle content is less than 2% by mass or more than 30% by mass of the entire toner particles, when the sum of the composition ratios of oxygen, hydrogen, and Group 13 elements to the total amount of elements constituting the inorganic protective layer is less than 0.95, or when the element composition ratio R of oxygen to Group 13 elements (oxygen / Group 13 elements) is less than 0.8 or more than 0.9, or when the ratio (W / R) of the resin particle content W to the element composition ratio R of oxygen to Group 13 elements (oxygen / Group 13 elements) is less than 1.05 or more than 37.5.

[0013] <2> According to the invention, an image forming apparatus is provided in which the ratio (W / R) of the resin particle content W to the elemental composition ratio R of oxygen to Group 13 elements (oxygen / Group 13 element) is less than 6.99 or more than 12.23, thereby realizing both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member.

[0014] <3> According to the present invention, an image forming apparatus is provided in which both abrasion of the cleaning blade and abrasion of the inorganic protective layer of the electrophotographic photosensitive member are reduced compared to when the number average particle diameter of the resin particles is less than 60 nm or exceeds 300 nm.

[0015] <4> According to the invention, the storage modulus G' of the resin particles is 1×10 5 In comparison with the case where the pressure is less than 100 Pa, an image forming apparatus is provided in which both the wear of the cleaning blade and the wear of the inorganic protective layer of the electrophotographic photosensitive member are reduced.

[0016] <5> According to the invention, the storage modulus G' of the components excluding the resin particles from the toner particles is 1×10 5 In comparison with the case where the temperature that reaches less than Pa exceeds 90°C, an image forming apparatus is provided in which both the wear of the cleaning blade and the wear of the inorganic protective layer of the electrophotographic photosensitive member are reduced.

[0017] <6> According to the invention relating to (1), an image forming apparatus is provided in which both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member are achieved, compared to when any of D1(90), D50(90), D1(150), and D50(150) is less than 0.5 or exceeds 2.0, and the value of D50(150)-D1(150) is 1.5 or more, or the value of D50(90)-D1(90) is 0.5 or more.

[0018] <7> According to the invention, an image forming apparatus is provided in which the wear of the cleaning blade and the wear of the inorganic protective layer of the electrophotographic photosensitive member are both reduced compared to when the resin particles are non-crosslinked resin particles.

[0019] <8> According to the invention, an image forming apparatus is provided in which wear of the cleaning blade and wear of the inorganic protective layer of the electrophotographic photosensitive member are both reduced compared to when the resin particles are polyester resin particles.

[0020] <9> According to the present invention, an image forming apparatus is provided in which, compared to when the toner contains only titanium oxide particles as an external additive, both the wear of the cleaning blade and the wear of the inorganic protective layer of the electrophotographic photosensitive member are reduced.

[0021] <10> According to the present invention, an image forming apparatus is provided in which, compared to when the toner contains only silica particles as an external additive, both the wear of the cleaning blade and the wear of the inorganic protective layer of the electrophotographic photosensitive member are reduced.

[0022] <11> According to the present invention, an image forming apparatus is provided in which the wear of the cleaning blade and the wear of the inorganic protective layer of the electrophotographic photosensitive member are both reduced compared to when the content of the external additive is less than 0.01% by mass or more than 5% by mass relative to the toner particles.

[0023] <12> According to the invention, an image forming apparatus is provided in which wear of the cleaning blade and wear of the inorganic protective layer of the electrophotographic photosensitive member are both reduced compared to when the Group 13 element is a Group 13 element other than gallium.

[0024] <13> According to the present invention, an image forming apparatus is provided in which both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member are achieved, compared to when the water contact angle is less than 95° or more than 100°.

[0025] <14> According to the invention, an image forming apparatus is provided in which wear of the cleaning blade and wear of the inorganic protective layer of the electrophotographic photosensitive member are both reduced compared to when the contact portion of the cleaning blade that comes into contact with the electrophotographic photosensitive member is made of a member having a 100% modulus at 23°C of less than 4 MPa or more than 18 MPa.

[0026] <15> According to the invention, in a process cartridge comprising: an electrophotographic photoreceptor having an inorganic protective layer containing oxygen, hydrogen, and a Group 13 element as the outermost surface layer; a developing device that stores a developer containing toner and develops an electrostatic latent image formed on the surface of the electrophotographic photoreceptor with the developer to form a toner image; and a cleaning device that has a cleaning blade that cleans the surface of the electrophotographic photoreceptor, when the content of resin particles is less than 2% by mass or more than 30% by mass with respect to the entire toner particles, the inorganic protective layer is This provides a process cartridge that achieves both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member, compared to when the sum of the constituent ratios of oxygen, hydrogen, and Group 13 elements to the total amount of elements is less than 0.95, or when the elemental constituent ratio R of oxygen to Group 13 elements (oxygen / Group 13 element) is less than 0.8 or exceeds 0.9, or when the ratio (W / R) of the resin particle content W to the elemental constituent ratio R of oxygen to Group 13 elements (oxygen / Group 13 element) is less than 1.05 or exceeds 37.5. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 2 is a schematic cross-sectional view showing an example of a layer structure of an electrophotographic photosensitive member in the image forming apparatus according to the present exemplary embodiment. FIG. [Figure 3] 1 is a schematic diagram illustrating an example of a film forming device used to form an inorganic protective layer of an electrophotographic photosensitive member in an image forming apparatus according to the present exemplary embodiment. [Figure 4] 3 is a schematic diagram for explaining the angle θ between the cleaning blade and the photosensitive member, and the pressing pressure N of the cleaning blade against the photosensitive member. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, an embodiment of the present invention will be described. These descriptions and examples are intended to illustrate the embodiment and are not intended to limit the scope of the invention. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of a numerical range may be replaced with a value shown in the examples. In this specification, (meth)acrylic means both acrylic and methacrylic.

[0029] In this specification, the term "process" refers not only to an independent process but also to a process clearly distinguished from other processes. Even if it is not possible to distinguish between the two, the term still includes the process as long as the intended purpose of the process is achieved. Each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, the amount refers to the total amount of those multiple substances present in the composition, unless otherwise specified.

[0030] [Image forming device] The image forming apparatus according to the present embodiment comprises an electrophotographic photosensitive member (hereinafter also referred to as "photosensitive member") having, as its outermost surface layer, an inorganic protective layer containing oxygen, hydrogen, and a Group 13 element; a charging device that contacts and charges the surface of the electrophotographic photosensitive member; an electrostatic image forming device that forms an electrostatic image on the surface of the charged electrophotographic photosensitive member; a developing device that stores a developer containing toner and develops the electrostatic image formed on the surface of the electrophotographic photosensitive member with the developer to form a toner image; a cleaning device that is provided downstream of the cleaning brush in the rotation direction of the electrophotographic photosensitive member and has a cleaning blade that cleans the surface of the electrophotographic photosensitive member; and a transfer device that transfers the toner image to the surface of a recording medium. In the image forming apparatus according to this embodiment, the toner contains toner particles containing a binder resin and resin particles, and external additives, and the content of the resin particles in the total toner particles is 2% by mass or more and 30% by mass or less. The sum of the composition ratios of oxygen, hydrogen, and Group 13 elements to the total amount of elements constituting the inorganic protective layer is 0.95 or more, and the element composition ratio R of oxygen to Group 13 elements (oxygen / Group 13 elements) is 0.8 or more and 1.9 or less. The ratio (W / R) of the content W of the resin particles to the elemental composition ratio R of oxygen to the Group 13 elements (oxygen / Group 13 elements) satisfies 1.05≦W / R≦37.5.

[0031] In the image forming apparatus according to the present embodiment, the above-described configuration achieves both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member. The reason for this is presumed to be as follows.

[0032] When the resin particle content is low, the toner particles have a soft surface, and external additives tend to be embedded in the surface of the toner particles, reducing the amount of external additives released. This means that the amount of external additives supplied to the contact point between the cleaning blade and the photoreceptor decreases, resulting in high friction due to insufficient lubrication, and thus accelerated cleaning blade wear. This phenomenon is particularly likely to occur during continuous image formation under conditions of high temperature, high humidity, and low image density.

[0033] On the other hand, if the content of resin particles is high, the surface of the toner particles becomes hard, the amount of liberated external additives increases excessively, and the amount of external additives supplied to the contact area between the cleaning blade and the photoreceptor tends to be excessive. That is, even in the case of a photoreceptor having an inorganic protective layer containing oxygen, hydrogen, and a Group 13 element as the outermost layer, the hard external additives increase the frequency of the surface being scraped off, thereby accelerating photoreceptor wear.

[0034] In contrast, in the image forming apparatus according to this embodiment, the content of the resin particles is set within the above range, thereby achieving an appropriate degree of separation of the external additive from the toner particles. When the sum of the respective constituent ratios of oxygen, hydrogen, and Group 13 elements relative to the total amount of elements constituting the inorganic protective layer, and the elemental constituent ratio R of oxygen to Group 13 elements (oxygen / Group 13 elements) are within the above ranges, the inorganic protective layer is endowed with high water repellency (i.e., low friction) in addition to hardness and chemical stability. This is thought to be because when there is an excess of Group 13 elements relative to oxygen, the inorganic protective layer deteriorates due to deficiency sites caused by oxygen vacancies. On the other hand, when there is an excess of oxygen relative to Group 13 elements, a stable material containing oxygen, hydrogen, and Group 13 elements as constituent elements cannot be obtained.

[0035] In addition, the ratio (W / R) of the content W of the resin particles to the elemental composition ratio R of oxygen to the Group 13 elements (oxygen / Group 13 elements) is set within the above range. If the ratio (W / R) exceeds 3.75, the surface of the toner particles becomes hard, the amount of external additives supplied becomes large, and it becomes difficult to ensure the hardness of the surface of the inorganic protective layer, which causes wear of the photoreceptor. If the ratio (W / R) is less than 1.05, the surface of the toner particles is soft, so external additives are easily embedded in the toner particle surface, reducing the amount of external additives released. Furthermore, the surface of the inorganic protective layer becomes excessively hard, making it impossible for the cleaning blade to adequately scrape off the surface of the protective layer during long-term image formation. In other words, in addition to the insufficient supply of external additives from the toner, it becomes difficult to remove discharge products adhering to the surface of the inorganic protective layer, resulting in high friction and blade wear.

[0036] On the other hand, when the ratio (W / R) is in the range of 1.05 or more and 3.75 or less, the hardness of the toner surface (i.e., the amount of external additive supplied) and the hardness of the inorganic protective layer surface (i.e., the ability to scrape off discharge products) and water repellency are in an appropriate relationship, thereby achieving sufficient lubrication function for cleaning and reducing wear on both the cleaning blade and the photosensitive member.

[0037] From the above, it is presumed that the image forming apparatus according to this embodiment achieves both reduced wear on the cleaning blade and reduced wear on the inorganic protective layer of the electrophotographic photosensitive member.

[0038] In the image forming apparatus according to this embodiment, the ratio (W / R) of the resin particle content W to the elemental composition ratio R of oxygen to Group 13 elements (oxygen / Group 13 elements) satisfies 1.05≦W / R≦3.75, but from the viewpoint of reducing blade wear and wear of the inorganic protective layer, it is preferable to satisfy 2.5≦W / R≦28, more preferably 3.0≦W / R≦20, and even more preferably 6.99≦W / R≦12.23. The content W of the resin particles and the elemental composition ratio R of oxygen to the Group 13 elements (oxygen / Group 13 elements) will be described in detail later.

[0039] Here, the image forming apparatus according to this embodiment is applicable to well-known image forming apparatuses such as a direct transfer type apparatus in which a toner image for developing an electrostatic charge image formed on the surface of a photosensitive member is directly transferred onto a recording medium; an intermediate transfer type apparatus in which a toner image for developing an electrostatic charge image formed on the surface of a photosensitive member is primarily transferred onto the surface of an intermediate transfer member, and the toner image for developing an electrostatic charge image transferred onto the surface of the intermediate transfer member is secondarily transferred onto the surface of a recording medium; and an apparatus equipped with a static eliminator that irradiates the surface of a photosensitive member with static eliminator light to eliminate static charge after the toner image for developing an electrostatic charge image is transferred and before charging.

[0040] In the case of an intermediate transfer type device, the transfer device may have a configuration including, for example, an intermediate transfer body onto whose surface a toner image for developing an electrostatic charge image is transferred, a primary transfer device that performs primary transfer of the toner image for developing an electrostatic charge image formed on the surface of a photosensitive body onto the surface of the intermediate transfer body, and a secondary transfer device that performs secondary transfer of the toner image for developing an electrostatic charge image transferred onto the surface of the intermediate transfer body onto the surface of a recording medium.

[0041] The image forming apparatus according to this embodiment may have a cartridge structure (process cartridge) in which a portion including at least the photosensitive member, the developing device, and the cleaning device is detachably attached to the image forming apparatus.

[0042] An example of an image forming apparatus according to the present embodiment will be described below, but the present invention is not limited to this. Note that only the main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0043] FIG. 1 is a schematic diagram showing an example of the configuration of an image forming apparatus according to the present embodiment. 1, an image forming apparatus 10 according to this embodiment is provided with, for example, a photoreceptor 12. The photoreceptor 12 is cylindrical and connected to a drive unit 27 such as a motor via a driving force transmission member (not shown) such as a gear, and is driven to rotate around a rotation axis indicated by a black dot by the drive unit 27. In the example shown in FIG. 1, the photoreceptor 12 is driven to rotate in the direction of arrow A.

[0044] 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 eliminator 24 are arranged in this order along the rotation direction of the photoreceptor 12. The image forming apparatus 10 also includes a fixing device 26 having a fixing member 26A and a pressure member 26B arranged in contact with the fixing member 26A. The image forming apparatus 10 also includes a control device 36 that controls the operation of each device (each section). 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 an image forming unit.

[0045] In the image forming apparatus 10, at least the photosensitive member 12, the developing device 18, and the cleaning device 22 may be provided as a process cartridge integrated with other devices.

[0046] Hereinafter, each device (each section) of the image forming apparatus 10 will be described in detail.

[0047] [Photoreceptor] The photoreceptor 12 has an inorganic protective layer containing oxygen and a Group 13 element as its outermost surface layer. Specifically, as shown in FIG. 2, the photoreceptor 12 has, on a conductive substrate 104, an undercoat layer 101 provided on the conductive substrate 104, a charge generation layer 102 provided on the undercoat layer 101, a charge transport layer 103 provided on the charge generation layer 102, and an inorganic protective layer 106 provided on the charge transport layer 103. The photoreceptor 12 has an organic photosensitive layer 105 whose functions are separated into a charge generating layer 102 and a charge transport layer 103. However, the photosensitive layer may be a single-layer organic photosensitive layer or an inorganic photosensitive layer. An intermediate layer may be provided between the conductive substrate 104 and the undercoat layer 101 .

[0048] Hereinafter, each layer of the photoreceptor 12 will be described in detail, but the reference numerals will be omitted.

[0049] (Inorganic protective layer) The inorganic protective layer contains oxygen, hydrogen, and a Group 13 element. The sum of the constituent ratios of oxygen, hydrogen, and Group 13 elements to the total amount of elements constituting the inorganic protective layer is 0.95 or more, and the elemental constituent ratio R of oxygen to Group 13 elements (oxygen / Group 13 elements) is 0.8 or more and 1.9 or less. The sum of the constituent ratios of oxygen, hydrogen and Group 13 elements to the total amount of elements constituting the inorganic protective layer is preferably 96 or more, more preferably 97 or more, from the viewpoint of reducing wear of the cleaning blade and the photoreceptor. The elemental composition ratio R of oxygen to Group 13 element (oxygen / Group 13 element) is preferably 1.0 or more and 1.6 or less, more preferably 1.3 or more and 1.5 or less, from the viewpoint of reducing wear of the cleaning blade and the photoreceptor.

[0050] Examples of Group 13 elements include aluminum, gallium, and indium. Among these, gallium is preferred as the Group 13 element. When gallium is used as the Group 13 element, the water repellency of the inorganic protective layer is enhanced. This improves the reduction in friction between the cleaning blade and the photoreceptor, further reducing wear between the cleaning blade and the photoreceptor.

[0051] The elemental composition ratio of the Group 13 element is preferably 3 atomic % or more and 42 atomic % or less, and more preferably 36 atomic % or more and 40 atomic % or less, based on all the constituent elements of the inorganic protective layer. The elemental composition ratio of oxygen is preferably 42 atomic % or more and 50 atomic % or less, and more preferably 44 atomic % or more and 48 atomic % or less, relative to all the constituent elements of the inorganic protective layer. The elemental composition ratio of hydrogen is, for example, preferably 14 atomic % or more and 24 atomic % or less, and more preferably 16 atomic % or more and 20 atomic % or less, relative to all the constituent elements of the inorganic protective layer. In particular, when the elemental composition ratio of each element is within the above range, the water repellency of the inorganic protective layer is enhanced, thereby improving the reduction in friction between the cleaning blade and the photoreceptor, and further reducing wear on the cleaning blade and the photoreceptor.

[0052] In addition to oxygen, hydrogen, and a Group 13 element, the inorganic protective layer may contain, for example, one or more elements selected from C, Si, Ge, and Sn in the case of n-type in order to control the conductivity type, or one or more elements selected from N, Be, Mg, Ca, and Sr in the case of p-type in order to control the conductivity type.

[0053] Here, the elemental composition ratio, atomic ratio, etc. of each element except hydrogen in the inorganic protective layer, including the distribution in the thickness direction, can be determined by Rutherford Backscattering (hereinafter referred to as "RBS"). The RBS uses an NEC 3SDH Pelletron as the accelerator, a CE&A RBS-400 as the end station, and a 3S-R10 as the system. CE&A's HYPRA program is used for analysis. The RBS measurement conditions are as follows: He++ ion beam energy 2.275 eV, detection angle 160°, and grazing angle with respect to the incident beam approximately 109°.

[0054] Specifically, the RBS measurement is performed as follows: First, a He++ ion beam is incident perpendicularly on the sample, and the detector is set at 160° to the ion beam to measure the backscattered He signal. The composition ratio and film thickness are determined from the detected He energy and intensity. To improve the accuracy of determining the composition ratio and film thickness, spectra can be measured at two detection angles. Accuracy can be improved by measuring at two detection angles with different depth resolutions and backscattering dynamics and cross-checking the results. The number of He atoms backscattered by a target atom is determined by only three factors: 1) the atomic number of the target atom, 2) the energy of the He atom before scattering, and 3) the scattering angle. The density is calculated from the measured composition and used to calculate the thickness. The density error is within 20%.

[0055] Next, the elemental composition ratio of hydrogen is determined by hydrogen forward scattering (hereinafter referred to as "HFS"). For the HFS measurement, we used an NEC 3SDH Pelletron as the accelerator, a CE&A RBS-400 as the end station, and a 3S-R10 as the system. CE&A's HYPRA program was used for analysis. The HFS measurement conditions were as follows: He++ ion beam energy: 2.275 eV Detection angle: 160° incident beam, Grazing angle 30°

[0056] HFS measurements are performed by setting the detector at 30° to the He++ ion beam and the sample at 75° from the normal, thereby picking up the signal of hydrogen scattered forward from the sample. It is advisable to cover the detector with aluminum foil to remove He atoms that scatter along with the hydrogen. Quantitative analysis is performed by comparing the hydrogen counts of a reference sample and the sample being measured after normalizing them by stopping power. A sample of silicon implanted with H ions and muscovite mica are used as reference samples. Muscovite is known to have a hydrogen concentration of 6.5. The amount of H adsorbed on the outermost surface is corrected by subtracting the amount of H adsorbed on a clean Si surface, for example.

[0057] -Characteristics of inorganic protective layer- The water contact angle of the inorganic protective layer is preferably 95° or more and 100° or less, and more preferably 95° or more and 99° or less. When the water contact angle of the inorganic protective layer is within the above range, the surface of the inorganic protective layer has high water repellency, which further reduces friction and makes blade wear and photoreceptor wear less likely to occur.

[0058] The water contact angle of the surface protective layer is the contact angle between the surface of the inorganic protective layer and water when pure water is used at a measurement temperature of 25° C. The measurement method is as follows. The contact angle is measured using a CA-S roll type contact angle meter manufactured by Kyowa Interface Science Co., Ltd. A drop of pure water is placed on the surface of the photoreceptor, and the value measured after 20 seconds is the water contact angle.

[0059] The inorganic protective layer is preferably a non-single-crystal film such as a microcrystalline film, a polycrystalline film, an amorphous film, etc. Among these, an amorphous film is preferred as the inorganic protective layer in terms of surface smoothness, and a microcrystalline film is preferred in terms of hardness. The growth cross section of the inorganic protective layer may have a columnar structure, but from the viewpoint of slipperiness, a highly flat structure is preferred, and an amorphous structure is more preferred. In this way, when the inorganic protective layer is an amorphous film, smoothness is increased, which improves the reduction in friction between the cleaning blade and the photosensitive member, and further reduces wear of the cleaning blade and the photosensitive member. The crystalline or amorphous nature can be determined by the presence or absence of dots or lines in a diffraction pattern obtained by RHEED (reflection high energy electron diffraction) measurement.

[0060] The volume resistivity of the inorganic protective layer is 5.0×10 7 Ωcm or more 1.0×10 12 Preferably less than 1.0×10 Ωcm 8 Ωcm or more 5.0×10 11 Ωcm or less is preferable, 5.0×10 8 Ωcm or more 2.0×10 11 It is more preferable that it is Ωcm or less. When the volume resistivity of the inorganic protective layer is within the above range, the flow of charges in the in-plane direction is suppressed, and good electrostatic latent image formation is easily achieved.

[0061] The volume resistivity of the inorganic protective layer is calculated from the resistance measured using an LCR meter ZM2371 manufactured by nF under conditions of a frequency of 1 kHz and a voltage of 1 V, based on the electrode area and sample thickness. The measurement sample may be a sample obtained by forming a film on an aluminum substrate under the same conditions as those for forming the inorganic protective layer to be measured, and then forming a gold electrode on the film by vacuum deposition, or may be a sample obtained by peeling off the inorganic protective layer from the electrophotographic photoreceptor after production, partially etching it, and sandwiching the resulting layer between a pair of electrodes.

[0062] The elastic modulus of the inorganic protective layer is preferably 30 GPa or more and 80 GPa or less, and more preferably 40 GPa or more and 65 GPa or less. When the elastic modulus of the inorganic protective layer is within the above range, the occurrence of depressions (dent-like scratches), peeling, or cracks in the inorganic protective layer is easily suppressed. The elastic modulus of the inorganic protective layer is determined by obtaining a depth profile by the continuous stiffness method (CSM) (U.S. Patent 4,848,141) using a Nano Indenter SA2 manufactured by MTS Systems, Inc., and using the average value obtained from the measurements at an indentation depth of 30 nm to 100 nm. The measurement conditions are as follows: Measurement environment: 23°C, 55% RH Indenter used: Diamond regular triangular pyramid indenter (Berkovic indenter) triangular pyramid indenter Test mode: CSM mode The measurement sample may be a sample formed on a substrate under the same conditions as when the inorganic protective layer to be measured was formed, or may be a sample obtained by peeling off the inorganic protective layer from the electrophotographic photoreceptor after production and then partially etching it.

[0063] The thickness of the inorganic protective layer is preferably, for example, 0.2 μm or more and 10.0 μm or less, and desirably 0.4 μm or more and 5.0 μm or less. When the thickness of the inorganic protective layer is within the above range, the occurrence of depressions (dent-like scratches), peeling, and cracks in the inorganic protective layer can be easily suppressed.

[0064] - Formation of inorganic protective layer - The protective layer can be formed by a known vapor deposition method such as plasma CVD (Chemical Vapor Deposition), metal organic chemical vapor deposition, molecular beam epitaxy, evaporation, or sputtering.

[0065] The formation of the inorganic protective layer will be described below by way of a specific example, with an example of a film forming apparatus shown in the drawings. Note that the following description will be given of a method for forming an inorganic protective layer containing gallium, oxygen, and hydrogen, but the present invention is not limited to this, and any known formation method may be applied depending on the composition of the desired inorganic protective layer.

[0066] FIG. 3 is a schematic diagram showing an example of a film forming apparatus used to form an inorganic protective layer of an electrophotographic photosensitive member in the image forming apparatus according to this embodiment. The film forming apparatus 130 includes a vacuum chamber 132 that is evacuated. Inside the vacuum chamber 132, a support member 146 is provided that supports a photoreceptor 150 (hereinafter referred to as a non-coated photoreceptor) on which an inorganic protective layer has not yet been formed, so that the photoreceptor 150 rotates around its axis of rotation in the longitudinal direction of the non-coated photoreceptor 150. The support member 146 is connected to a motor 148 via a support shaft 152 that supports the support member 146, and is configured so that the driving force of the motor 148 can be transmitted to the support member 146 via the support shaft 152.

[0067] After the non-coated photosensitive member 150 is held by the support member 146, the motor 148 is driven, and the driving force of the motor 148 is transmitted to the non-coated photosensitive member 150 via the support shaft 152 and the support member 146, causing the non-coated photosensitive member 150 to rotate with its longitudinal direction as the rotation axis.

[0068] An exhaust pipe 142 for exhausting gas from the vacuum chamber 132 is provided at one end of the vacuum chamber 132. One end of the exhaust pipe 142 is connected to the interior of the vacuum chamber 132 via an opening 142A of the vacuum chamber 132, and the other end is connected to a vacuum exhaust device 144. The vacuum exhaust device 144 is made up of one or more vacuum pumps, and may be provided with a mechanism for adjusting the exhaust speed, such as a conductance valve, as necessary.

[0069] When the air inside the vacuum chamber 132 is exhausted through the exhaust pipe 142 by driving the vacuum exhaust device 144, the inside of the vacuum chamber 132 is depressurized to a target pressure (i.e., ultimate vacuum). Note that this ultimate vacuum is preferably 1 Pa or less, and more preferably 0.1 Pa or less. The element composition ratio (oxygen / Group 13 element) is controlled by the ratio of the supply rates of the gallium raw material and oxygen.

[0070] A discharge electrode 154 is provided near the uncoated photoreceptor 150 installed inside the vacuum chamber 132. The discharge electrode 154 is electrically connected to a high-frequency power supply 158 via a matching box 156. As the high-frequency power supply 158, for example, a DC power supply or an AC power supply can be used, but it is preferable to use an AC high-frequency power supply because it excites the gas efficiently.

[0071] The discharge electrode 154 is plate-shaped, and its longitudinal direction is aligned with the rotational axis (longitudinal direction) of the uncoated photoreceptor 150. The discharge electrode 154 is spaced a predetermined distance from the outer peripheral surface of the uncoated photoreceptor 150. The discharge electrode 154 is hollow (having a cavity structure) and has one or more openings 134A for supplying a gas that generates plasma to the discharge surface. If the discharge electrode 154 is not hollow and has no openings 134A on the discharge surface, the gas that generates plasma may be supplied from a separately provided gas supply port and pass between the uncoated photoreceptor 150 and the discharge electrode 154. To prevent discharge between the discharge electrode 154 and the vacuum chamber 132, it is preferable that the electrode surface other than the surface facing the uncoated photoreceptor 150 be covered by a grounded member with a clearance of approximately 3 mm or less. When high frequency power is supplied from a high frequency power supply 158 to the discharge electrode 154 via a matching box 156, the discharge electrode 154 generates a discharge.

[0072] In the area of ​​the vacuum chamber 132 facing the non-coated photosensitive member 150 via the discharge electrode 154, a gas supply pipe 134 is provided for supplying gas toward the non-coated photosensitive member 150 in the vacuum chamber 132 via the inside of the hollow discharge electrode 154. One end of the gas supply pipe 134 is connected to the inside of the discharge electrode 154 (i.e., connected to the inside of the vacuum chamber 132 via the discharge electrode 154 and the opening 134A), and the other end is connected to each of the gas supply devices 141A, 141B, and 141C.

[0073] Each of the gas supply devices 141A, 141B, and 141C includes an MFC (i.e., mass flow controller) 136 for adjusting the amount of gas supplied, a pressure regulator 138, and a gas supply source 140. The gas supply source 140 of each of the gas supply devices 141A, 141B, and 141C is connected to the other end of the gas supply pipe 134 via the pressure regulator 138 and the MFC 136.

[0074] The gas in the gas supply source 140 is supplied toward the non-coated photosensitive element 150 in the vacuum chamber 132 via the gas supply pipe 134, the discharge electrode 154, and the opening 134A, while the supply pressure is adjusted by the pressure regulator 138 and the gas supply amount is adjusted by the MFC 136. The type of gas filled in the gas supply sources 140 included in each of the gas supply devices 141A, 141B, and 141C may be the same type, but when processing is performed using a plurality of gases, gas supply sources 140 filled with different types of gases may be used. In this case, different types of gases are supplied from the gas supply sources 140 of the gas supply devices 141A, 141B, and 141C to the gas supply pipes 134, and the mixed gas is then supplied toward the non-coated photoreceptor 150 in the vacuum chamber 132 via the discharge electrode 154 and the opening 134A.

[0075] A raw material gas containing gallium is also supplied to the uncoated photoreceptor 150 in the vacuum chamber 132. The raw material gas is introduced into the vacuum chamber 132 from a raw material gas supply source 162 through a gas inlet pipe 164 having a shower nozzle 164A at its tip. The raw material gas may be, for example, a compound gas containing gallium such as trimethylgallium or triethylgallium, or metallic gallium. Furthermore, an oxygen source may be O2 or another substance containing oxygen. In the example shown in FIG. 3, the discharge method by the discharge electrode 154 is a capacitive type, but it may be an inductive type.

[0076] Film formation is performed, for example, as follows: First, with the inside of vacuum chamber 132 depressurized to a predetermined pressure by vacuum exhaust device 144, high-frequency power is supplied to discharge electrode 154 from high-frequency power supply 158 via matching box 156, and a gas for generating plasma is introduced into vacuum chamber 132 from gas supply pipe 134. At this time, plasma is formed so as to spread radially from the discharge surface side of discharge electrode 154 toward opening 142A of exhaust pipe 142. The pressure inside the vacuum chamber 132 during the plasma generation is preferably 1 Pa or more and 500 Pa or less.

[0077] The gas that forms the plasma contains oxygen. It may also be a mixed gas containing an inert gas (He, Ar, etc.) or a non-film-forming gas (H, etc.). The non-film-forming gas or inert gas is used to control the reaction atmosphere, such as the pressure inside the reaction vessel. Hydrogen, in particular, is advantageous for reactions at low temperatures.

[0078] Next, hydrogen from carrier gas supply source 160 is passed through raw material gas supply source 162, and using hydrogen as a carrier gas, hydrogen-diluted trimethylgallium gas (an example of an organometallic compound containing gallium) is introduced into vacuum chamber 132 via gas inlet pipe 164 and shower nozzle 164A, causing activated oxygen and trimethylgallium to react in an atmosphere containing active hydrogen, and a film containing hydrogen, oxygen, and gallium is formed on the surface of non-coated photoreceptor 150.

[0079] It is preferable to mix O2 gas and H2 gas and introduce the mixture into the discharge electrode 154, simultaneously creating active species to decompose the trimethylgallium gas and form a film of a hydrogen-containing compound of gallium and oxygen on the non-coated photoreceptor 150. By simultaneously activating hydrogen gas and oxygen gas in a plasma and reacting with an organometallic compound containing gallium, the activated hydrogen generated by the plasma discharge can etch hydrocarbon groups (methyl groups, ethyl groups, etc.) contained in the organometallic gas. This allows a film of a compound containing gallium and oxygen, with film quality equivalent to that grown at high temperatures (e.g., 200°C to 600°C), to be formed on the surface of an organic material (organic photosensitive layer) without damaging the organic material, even at low temperatures.

[0080] When the inorganic protective layer is formed by plasma CVD, the O / Ga element composition ratio is controlled by, for example, the supply amounts of the gallium raw material and the oxygen raw material. In other methods, the growth atmosphere is controlled by changing the amount of gas supplied, or in the case of sputtering, the ratio of gallium to oxygen contained in the target is controlled.

[0081] 3 uses a high-frequency oscillator to generate plasma, but the plasma generation method is not limited to this. For example, a microwave oscillator, an electrocyclotron resonance system, or a helicon plasma system may be used. In addition, the high-frequency oscillator may be either an induction type or a capacitance type.

[0082] 3, a plasma generator is configured using a discharge electrode 154, a high-frequency power supply 158, a matching box 156, a gas supply pipe 134, an MFC 136, a pressure regulator 138, and a gas supply source 140. However, two or more types of plasma generators may be used in combination, or two or more devices of the same type may be used. Furthermore, a capacitively coupled plasma CVD device having a cylindrical electrode surrounding a cylindrical uncoated photoreceptor 150 may be used, or a device that generates a discharge between parallel plate electrodes and the uncoated photoreceptor 150 may be used.

[0083] When two or more different types of plasma generators are used, they must be simultaneously discharged at the same pressure. A pressure difference may be created between the discharge area and the film-forming area (the area where the uncoated photoreceptor 150 is installed). These devices may be arranged in series with respect to the gas flow formed within the processing apparatus from the gas introduction area to the gas exhaust area, or each device may be arranged facing the film-forming surface of the uncoated photoreceptor 150.

[0084] Alternatively, the discharge may be carried out under atmospheric pressure, which means a pressure of 70,000 Pa or more and 110,000 Pa or less. In this case, the discharge can be more easily stabilized by using a rare gas such as He or Ar gas mixed with hydrogen.

[0085] The method for forming the inorganic protective layer has been described above as an example in which the inorganic protective layer has constituent elements of hydrogen, oxygen, and gallium. However, when the inorganic protective layer is a layer having constituent elements of oxygen and gallium (not containing hydrogen), it can be formed by, for example, sputtering, electron beam evaporation, or molecular beam epitaxy.

[0086] (Conductive substrate) Examples of conductive substrates include metal plates, metal drums, and metal belts containing metals (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.). Other examples of conductive substrates include paper, resin films, belts, etc. coated, vapor-deposited, or laminated with conductive compounds (e.g., conductive polymers, indium oxide, etc.), metals (e.g., aluminum, palladium, gold, etc.), or alloys. Here, "conductive" refers to a material having a volume resistivity of 10 13 This means that the resistance is less than Ωcm.

[0087] When the electrophotographic photoreceptor is used in a laser printer, the surface of the conductive substrate is preferably roughened to a center line average roughness Ra of 0.04 μm to 0.5 μm inclusive in order to suppress interference fringes that occur when irradiated with laser light. When incoherent light is used as the light source, roughening to prevent interference fringes is not particularly necessary, but it is suitable for extending the life of the conductive substrate by suppressing defects caused by surface irregularities.

[0088] The conductive substrate may be subjected to a treatment with an acidic treatment solution or a boehmite treatment.

[0089] (subbing layer) The undercoat layer is, for example, a layer containing inorganic particles and a binder resin.

[0090] As inorganic particles, for example, powder resistance (volume resistivity) 10 2 Ωcm or more 10 11 Examples include inorganic particles with a particle size of Ωcm or less. Among these, inorganic particles having the above resistance value are preferably metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles, with zinc oxide particles being particularly preferred.

[0091] The specific surface area of ​​inorganic particles measured by the BET method is, for example, 10 m 2 / g or more is preferable. The volume average particle size of the inorganic particles is, for example, 50 nm or more and 2000 nm or less (preferably 60 nm or more and 1000 nm or less).

[0092] The content of the inorganic particles is, for example, preferably 10% by mass or more and 80% by mass or less, more preferably 40% by mass or more and 80% by mass or less, relative to the binder resin.

[0093] The inorganic particles may be surface-treated, and two or more types of inorganic particles having different surface treatments or different particle sizes may be used in combination.

[0094] Examples of the surface treatment agent include a silane coupling agent, a titanate-based coupling agent, an aluminum-based coupling agent, a surfactant, etc. In particular, a silane coupling agent is preferred, and a silane coupling agent having an amino group is more preferred.

[0095] Here, it is preferable that the undercoat layer contains an electron-accepting compound (that is, an acceptor compound) together with the inorganic particles, from the viewpoint of improving the long-term stability of the electrical properties and the carrier blocking property.

[0096] Examples of electron-accepting compounds include electron-transporting substances such as quinone compounds such as chloranil and bromoanil; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone; oxadiazole compounds such as 2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole, 2,5-bis(4-naphthyl)-1,3,4-oxadiazole and 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole; xanthone compounds; thiophene compounds; and diphenoquinone compounds such as 3,3',5,5'-tetra-t-butyldiphenoquinone. In particular, the electron-accepting compound is preferably a compound having an anthraquinone structure, such as a hydroxyanthraquinone compound, an aminoanthraquinone compound, or an aminohydroxyanthraquinone compound, and specifically, for example, anthraquinone, alizarin, quinizarin, anthrarphine, or purpurin.

[0097] The electron-accepting compound may be contained in the undercoat layer in a dispersed state together with the inorganic particles, or may be contained in a state of being attached to the surface of the inorganic particles.

[0098] The attachment of the electron-accepting compound may be carried out before or after the inorganic particles are surface-treated with a surface-treating agent, or the attachment of the electron-accepting compound and the surface-treatment with a surface-treating agent may be carried out simultaneously.

[0099] The content of the electron-accepting compound is, for example, 0.01% by mass or more and 20% by mass or less, and preferably 0.01% by mass or more and 10% by mass or less, based on the inorganic particles.

[0100] Examples of binder resins used in the undercoat layer include known polymer compounds such as acetal resins (e.g., polyvinyl butyral, etc.), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, unsaturated polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, urea resins, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins, alkyd resins, and epoxy resins; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; titanium alkoxide compounds; organic titanium compounds; and silane coupling agents. Examples of binder resins used in the undercoat layer include charge transporting resins having charge transporting groups, conductive resins (such as polyaniline), and the like.

[0101] Among these, the binder resin used in the undercoat layer is preferably a resin that is insoluble in the coating solvent of the upper layer, and in particular, a resin obtained by reacting at least one resin selected from the group consisting of thermosetting resins such as urea resins, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins, unsaturated polyester resins, alkyd resins, and epoxy resins, and polyamide resins, polyester resins, polyether resins, methacrylic resins, acrylic resins, polyvinyl alcohol resins, and polyvinyl acetal resins with a curing agent is preferred. When two or more of these binder resins are used in combination, the mixing ratio is set as necessary.

[0102] The undercoat layer may contain various additives to improve electrical properties, environmental stability, and image quality. Examples of additives include known materials such as polycyclic condensation and azo electron transport pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, and silane coupling agents. Silane coupling agents are used for the surface treatment of inorganic particles as described above, and may also be added to the undercoat layer as an additive.

[0103] These additives may be used alone or as a mixture or polycondensate of a plurality of compounds.

[0104] The undercoat layer preferably has a Vickers hardness of 35 or more. The surface roughness (ten-point average roughness) of the undercoat layer is preferably adjusted to between 1 / (4n) (n is the refractive index of the upper layer) and 1 / 2 of the wavelength λ of the exposure laser used to suppress moiré images. Resin particles or the like may be added to the undercoat layer to adjust the surface roughness. Examples of resin particles include silicone resin particles and crosslinked polymethyl methacrylate resin particles. The surface of the undercoat layer may be polished to adjust the surface roughness. Examples of polishing methods include buffing, sandblasting, wet honing, and grinding.

[0105] The formation of the undercoat layer is not particularly limited, and a well-known formation method can be used. For example, the undercoat layer can be formed by forming a coating film of a coating liquid for forming the undercoat layer in which the above components are added to a solvent, drying the coating film, and heating it as necessary.

[0106] The thickness of the undercoat layer is set, for example, preferably at least 15 μm, more preferably in the range of 20 μm to 50 μm.

[0107] (middle class) Although not shown, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer. The intermediate layer is, for example, a layer containing a resin. Examples of the resin used in the intermediate layer include polymer compounds such as acetal resins (such as polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenol-formaldehyde resins, and melamine resins. The intermediate layer may be a layer containing an organometallic compound. Examples of the organometallic compound used in the intermediate layer include organometallic compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon. The compounds used in the intermediate layer may be used alone or as a mixture or polycondensation product of a plurality of compounds.

[0108] Among these, the intermediate layer is preferably a layer containing an organometallic compound containing zirconium atoms or silicon atoms.

[0109] The formation of the intermediate layer is not particularly limited, and a well-known formation method can be used. For example, the intermediate layer can be formed by forming a coating film of a coating liquid for forming an intermediate layer in which the above components are added to a solvent, drying the coating film, and heating it if necessary. The coating method for forming the intermediate layer may be a conventional method such as dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, or curtain coating.

[0110] The thickness of the intermediate layer is preferably set in the range of, for example, 0.1 μm to 3 μm. The intermediate layer may also be used as an undercoat layer.

[0111] (charge generation layer) The charge generation layer is, for example, a layer containing a charge generation material and a binder resin. Alternatively, the charge generation layer may be a vapor-deposited layer of the charge generation material. A vapor-deposited layer of the charge generation material is suitable for use with an incoherent light source such as an LED (Light Emitting Diode) or an organic EL (Electro-Luminescence) image array.

[0112] Examples of the charge generating material include azo pigments such as bisazo and trisazo; fused-ring aromatic pigments such as dibromoanthanthrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; and trigonal selenium.

[0113] Among these, in order to be compatible with laser exposure in the near-infrared region, it is preferable to use a metal phthalocyanine pigment or a metal-free phthalocyanine pigment as the charge generating material. Specifically, for example, hydroxygallium phthalocyanine disclosed in JP-A-5-263007 and JP-A-5-279591, chlorogallium phthalocyanine disclosed in JP-A-5-98181, dichlorotin phthalocyanine disclosed in JP-A-5-140472 and JP-A-5-140473, and titanyl phthalocyanine disclosed in JP-A-4-189873 are more preferable.

[0114] On the other hand, in order to accommodate laser exposure in the near-ultraviolet region, preferred charge-generating materials include fused-ring aromatic pigments such as dibromoanthanthrone; thioindigo pigments; porphyrazine compounds; zinc oxide; trigonal selenium; and bisazo pigments disclosed in JP-A-2004-78147 and JP-A-2005-181992.

[0115] The above charge-generating materials may also be used when using incoherent light sources such as LEDs and organic EL image arrays that emit light at a central wavelength of 450 nm to 780 nm. However, from the viewpoint of resolution, when using a thin photosensitive layer of 20 μm or less, the electric field strength in the photosensitive layer becomes high, and charge injection from the substrate can easily cause a decrease in charging, resulting in image defects known as black spots. This problem becomes more pronounced when using charge-generating materials that are p-type semiconductors, such as trigonal selenium and phthalocyanine pigments, that are prone to generating dark current.

[0116] In contrast, when an n-type semiconductor such as a fused-ring aromatic pigment, a perylene pigment, or an azo pigment is used as the charge-generating material, dark current is unlikely to occur, and image defects known as black spots can be suppressed even when the material is made into a thin film. Examples of n-type charge-generating materials include, but are not limited to, compounds (CG-1) to (CG-27) described in paragraphs

[0288] to

[0291] of JP-A-2012-155282. The n-type is determined by the polarity of the photocurrent that flows using the commonly used time-of-flight method, and those that flow more easily as electrons than holes as carriers are considered to be n-type.

[0117] The binder resin used in the charge generating layer may be selected from a wide range of insulating resins, and may also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Examples of binder resins include polyvinyl butyral resin, polyarylate resin (polycondensation product of bisphenols and aromatic dicarboxylic acids, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin, polyacrylamide resin, polyvinylpyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinylpyrrolidone resin, etc. Here, "insulating" means a resin having a volume resistivity of 10 13 This means that the resistance is Ωcm or more. These binder resins may be used alone or in combination of two or more.

[0118] The compounding ratio of the charge generating material to the binder resin is preferably within the range of 10:1 to 1:10 by mass.

[0119] The charge generating layer may contain other well-known additives.

[0120] The formation of the charge generation layer is not particularly limited, and a well-known formation method can be used. For example, the charge generation layer can be formed by forming a coating film of a coating liquid for forming the charge generation layer by adding the above components to a solvent, drying the coating film, and heating it as necessary. The charge generation layer can also be formed by vapor deposition of the charge generation material. Formation of the charge generation layer by vapor deposition is particularly suitable when a fused ring aromatic pigment or a perylene pigment is used as the charge generation material.

[0121] The thickness of the charge generating layer is set, for example, preferably in the range of 0.1 μm to 5.0 μm, more preferably 0.2 μm to 2.0 μm.

[0122] (charge transport layer) The charge transport layer is, for example, a layer containing a charge transport material and a binder resin, or may be a layer containing a polymer charge transport material.

[0123] Examples of charge transport materials include electron transport compounds such as quinone compounds such as p-benzoquinone, chloranil, bromanil, and anthraquinone; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds; cyanovinyl compounds; and ethylene compounds. Examples of charge transport materials also include hole transport compounds such as triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, and hydrazone compounds. These charge transport materials may be used alone or in combination, but are not limited to these.

[0124] As the charge transport material, triarylamine derivatives and benzidine derivatives are preferred from the viewpoint of charge mobility.

[0125] As the polymer charge transport material, known materials having charge transport properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 are particularly preferred. The polymer charge transport material may be used alone or in combination with a binder resin.

[0126] Examples of binder resins used in the charge transport layer include polycarbonate resins, polyester resins, polyarylate resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl acetate resins, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, silicone resins, silicone alkyd resins, phenol-formaldehyde resins, styrene-alkyd resins, poly-N-vinylcarbazole, and polysilanes. Among these, polycarbonate resins or polyarylate resins are preferred as binder resins. These binder resins may be used alone or in combination of two or more. The compounding ratio of the charge transport material to the binder resin is preferably from 10:1 to 1:5 by mass.

[0127] The charge transport layer may contain other well-known additives.

[0128] The formation of the charge transport layer is not particularly limited, and a well-known formation method can be used. For example, the charge transport layer can be formed by forming a coating film of a coating liquid for forming the charge transport layer in which the above components are added to a solvent, drying the coating film, and heating it if necessary.

[0129] The thickness of the charge transport layer is set, for example, preferably in the range of 5 μm to 50 μm, more preferably 10 μm to 30 μm.

[0130] (single-layer photosensitive layer) The single-layer photosensitive layer (charge generation / charge transport layer) is a layer containing, for example, a charge generation material, a charge transport material, and, if necessary, a binder resin and other well-known additives. Note that these materials are the same as those described for the charge generation layer and the charge transport layer. The content of the charge generating material in the single-layer photosensitive layer is preferably 0.1% by mass to 10% by mass, and more preferably 0.8% by mass to 5% by mass, based on the total solid content. The content of the charge transport material in the single-layer photosensitive layer is preferably 5% by mass to 50% by mass, based on the total solid content. The method for forming the single-layer photosensitive layer is the same as the method for forming the charge generating layer and the charge transport layer. The thickness of the single-layer photosensitive layer is, for example, 5 μm or more and 50 μm or less, and preferably 10 μm or more and 40 μm or less.

[0131] [Charging device] The charging device 15 charges the surface of the photoreceptor 12. The charging device 15 is provided, for example, in contact with or without contact with the surface of the photoreceptor 12 and includes a charging member 14 that charges the surface of the photoreceptor 12, and a power source 28 (an example of a voltage application unit for a charging member) that applies a charging voltage to the charging member 14. The power source 28 is electrically connected to the charging member 14.

[0132] The charging member 14 of the charging device 15 may be, for example, a contact-type charger using a conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, etc. The charging member 14 may also be, for example, a non-contact-type roller charger, or a charger known per se, such as a scorotron charger or corotron charger that utilizes corona discharge.

[0133] [Electrostatic image forming device] The electrostatic image forming device 16 forms an electrostatic image on the surface of the charged photoreceptor 12. Specifically, for example, the electrostatic image forming device 16 irradiates the surface of the photoreceptor 12, which has been charged by the charging member 14, with light L modulated based on image information of the image to be formed, and forms an electrostatic image on the photoreceptor 12 according to the image of the image information.

[0134] The electrostatic image forming device 16 may be, for example, an optical system having a light source that exposes light such as semiconductor laser light, LED light, or liquid crystal shutter light in an imagewise manner.

[0135] [Developing device] The developing device 18 is provided, for example, downstream in the rotation direction of the photoconductor 12 from the position where light L is irradiated by the electrostatic image forming device 16. A storage section for storing a developer is provided within the developing device 18. This storage section stores an electrostatic image developer having a specific electrostatic image developing toner. The electrostatic image developing toner is stored, for example, in a charged state within the developing device 18.

[0136] The developing device 18 includes a developing member 18A that develops the electrostatic image formed on the surface of the photoreceptor 12 with a developer containing, for example, toner for developing the electrostatic image, and a power source 32 that applies a development voltage to the developing member 18A. The developing member 18A is electrically connected to the power source 32, for example.

[0137] The developing member 18A of the developing device 18 is selected depending on the type of developer, and may be, for example, a developing roll having a developing sleeve with a built-in magnet.

[0138] The developing device 18 (including the power source 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 is 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 the toner for developing an electrostatic image contained in the developer from inside the developing device 18 to the surface of the photoconductor 12. On the surface of the photoconductor 12 to which the toner for developing an electrostatic image has been supplied, the formed electrostatic image is developed into a toner image for developing an electrostatic image.

[0139] [Transfer device] The transfer device 31 is provided, for example, downstream of the position where the developing member 18A is disposed in the rotation direction of the photoreceptor 12. The transfer device 31 includes, for example, a transfer member 20 that transfers the toner image for developing an electrostatic charge image formed on the surface of the photoreceptor 12 to the recording medium 30A, and a power source 30 that applies a transfer voltage to the transfer member 20. The transfer member 20 is, for example, cylindrical, and conveys the recording medium 30A while sandwiching it between itself and the photoreceptor 12. The transfer member 20 is, for example, electrically connected to the power source 30.

[0140] Examples of the transfer member 20 include contact-type transfer chargers using a belt, roller, film, rubber cleaning blade, etc., and non-contact-type transfer chargers known per se, such as a scorotron transfer charger or corotron transfer charger that utilizes corona discharge.

[0141] 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 is applied is charged to a transfer potential corresponding to the transfer voltage.

[0142] When a transfer voltage of the opposite polarity to the electrostatic image developing toner constituting the electrostatic image developing toner image formed on the photosensitive member 12 is applied to the transfer member 20 from the power source 30 of the transfer member 20, for example, in the area where the photosensitive member 12 and the transfer member 20 face each other (see transfer area 32A in Figure 1), a transfer electric field of an electric field strength is formed that moves each electrostatic image developing toner constituting the electrostatic image developing toner image on the photosensitive member 12 from the photosensitive member 12 to the transfer member 20 side by electrostatic force.

[0143] The recording medium 30A is housed, for example, in a storage unit (not shown), and is transported from this storage unit along a transport path 34 by multiple transport members (not shown) to a transfer area 32A, which is an area where the photoconductor 12 and the transfer member 20 face each other. In the example shown in FIG. 1 , the recording medium 30A is transported in the direction of arrow B. When the recording medium 30A reaches the transfer area 32A, the toner image for developing an electrostatic charge image on the photoconductor 12 is transferred to the recording medium 30A by a transfer electric field formed in the area by applying a transfer voltage to the transfer member 20. That is, for example, the toner image for developing an electrostatic charge image moves from the surface of the photoconductor 12 to the recording medium 30A, and the toner image for developing an electrostatic charge image is transferred onto the recording medium 30A. The toner image for developing an electrostatic charge image on the photoconductor 12 is then transferred onto the recording medium 30A by the transfer electric field.

[0144] [Cleaning device] The cleaning device 22 is provided downstream of the transfer device 31 in the rotation direction of the photoreceptor 12. The cleaning device 22 transfers the toner image for developing an electrostatic image onto the recording medium 30A and cleans the residual toner and the like adhering to the photoreceptor 12. Specifically, the cleaning device 22 cleans not only the residual toner but also adhering materials such as discharge products generated by the charging means and paper dust.

[0145] The cleaning device 22 includes a cleaning blade 220 . The cleaning blade 220 cleans the surface of the photoreceptor 12. For example, the cleaning blade 220 cleans the surface of the photoreceptor 12 by contacting the photoreceptor 12 with its tip facing in a direction opposite to the rotation direction of the photoreceptor 12.

[0146] The cleaning blade 220 may have, for example, a single layer structure, a two layer structure, a three or more layer structure, or other structure. An example of the single-layer cleaning blade 220 is a cleaning blade that is made entirely of a single material, including the contact portion that comes into contact with the photoreceptor 12 (that is, a cleaning blade made of a contact member). An example of a two-layer cleaning blade 220 is a cleaning blade having a first layer made of a contact member including a contact portion that comes into contact with the photosensitive member 12, and a second layer serving as a back layer formed on the back side of the first layer and made of a material different from that of the contact member. An example of the cleaning blade 220 having three or more layers is a cleaning blade having another layer between the first and second layers of the two-layer cleaning blade. The cleaning blade 220 is used while being supported on, for example, a rigid plate-like support member.

[0147] The cleaning blade 220 is made of elastic materials such as silicone rubber, fluororubber, ethylene-propylene-diene rubber, and polyurethane rubber, of which polyurethane rubber is preferred due to its excellent mechanical properties such as abrasion resistance, chipping resistance, and creep resistance.

[0148] In particular, the contact portion of the cleaning blade 220 that comes into contact with the photoreceptor 12 is preferably made of a material having a 100% modulus of 4 MPa or more and 18 MPa or less at 23° C. The 100% modulus is more preferably 8 MPa or more and 13 MPa or less. When a cleaning blade 220 having the above characteristics at the contact portion that comes into contact with the photosensitive member 12 is used, the cleaning blade 220 is less likely to wear out even if a load is applied to the cleaning blade 220 when the external additive passes between the blade and the photosensitive member.

[0149] The 100% modulus at 23°C is measured as follows: According to JIS-K6251, a dumbbell-shaped No. 3 test piece was prepared and measured at 23°C and a tensile speed of 500 mm / min, and the stress at 100% strain was determined. The measuring device used was a Strograph AE Elastomer manufactured by Toyo Seiki Co., Ltd.

[0150] The angle θ between the cleaning blade 220 and the photoreceptor 12 is preferably set to be equal to or greater than 5° and equal to or less than 35°, and more preferably set to be equal to or greater than 10° and equal to or less than 25°. The pressure N of the cleaning blade 220 against the photosensitive member 12 is 0.6 gf / mm 2 Over 6.0gf / mm 2 It is preferable to set it as follows: Here, the angle θ specifically refers to the angle formed by the tangent line (the dashed line in FIG. 4) at the contact point between the tip of the cleaning blade 220 and the photosensitive member 12 and the non-deformed portion of the cleaning blade 220, as shown in FIG. 4. The pressing pressure N is the pressure (gf / mm ) that the cleaning blade 220 presses toward the center of the photosensitive member 12 at the position where it contacts the photosensitive member 12, as shown in FIG. 2 )

[0151] A support member (not shown in FIG. 4) is joined to the surface of the cleaning blade 220 opposite to the surface that comes into contact with the photoreceptor 12, and the cleaning blade 220 is supported by this support member. This support member presses the cleaning blade 220 against the photoreceptor 12 with the above-mentioned pressing pressure. Examples of the support member include metal materials such as aluminum and stainless steel. An adhesive layer made of an adhesive or the like may be provided between the support member and the cleaning blade 220 to bond them together.

[0152] The cleaning device 22 may include a cleaning brush in addition to the cleaning blade 220 .

[0153] [Static eliminator] The static eliminator 24 is provided, for example, downstream of the cleaning device 22 in the rotation direction of the photoreceptor 12. After the toner image for developing an electrostatic charge image has been transferred, the static eliminator 24 exposes the surface of the photoreceptor 12 to remove static electricity. Specifically, for example, the static eliminator 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.

[0154] The static eliminator 24 may be, for example, a device having a light source such as a tungsten lamp that emits white light or a light emitting diode (LED) that emits red light.

[0155] [Fusing device] The fixing device 26 is provided, for example, downstream of the transfer area 32A in the conveyance direction of the conveyance path 34 for the recording medium 30A. The fixing device 26 has a fixing member 26A and a pressure member 26B arranged in contact with the fixing member 26A, and fixes the toner image for developing an electrostatic image transferred onto the recording medium 30A at the contact portion between the fixing member 26A and the pressure member 26B. Specifically, for example, the fixing device 26 is electrically connected to a control device 36 provided in the image forming apparatus 10, and is driven and controlled by the control device 36 to fix the toner image for developing an electrostatic image transferred onto the recording medium 30A to the recording medium 30A by heat and pressure.

[0156] The fixing device 26 may be a known fixing device, such as a heat roller fixing device or an oven fixing device. Specifically, for example, the fixing device 26 is a well-known fixing device including a fixing roll or a fixing belt as the fixing member 26A and a pressure roll or a pressure belt as the pressure member 26B.

[0157] Here, the recording medium 30A, onto which the electrostatic image developing toner image has been transferred by being transported along the transport path 34 and passing through the area (transfer area 32A) where the photosensitive member 12 and the transfer member 20 face each other, is further transported along the transport path 34 by, for example, a transport member not shown to the installation position of the fixing device 26, where the electrostatic image developing toner image on the recording medium 30A is fixed.

[0158] The recording medium 30A on which the image is formed by fixing the electrostatic image developing toner image is discharged by a plurality of conveying members (not shown) to the outside of the image forming apparatus 10. After the photoreceptor 12 is neutralized by the neutralization device 24, it is again charged to a charging potential by the charging device 15.

[0159] [Operation of image forming device] An example of the operation of the image forming apparatus 10 according to this embodiment will be described. Note that the various operations of the image forming apparatus 10 are performed by a control program executed by the control device 36.

[0160] 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. As a result, an electrostatic image corresponding to the image information is formed on the photoreceptor 12. In the developing device 18, the electrostatic image formed on the surface of the photoreceptor 12 is developed with a developer containing a specific electrostatic image developing toner. As a result, a toner image for developing an electrostatic image is formed on the surface of the photoreceptor 12. In the transfer device 31, the toner image for developing an electrostatic charge image formed on the surface of the photoreceptor 12 is transferred to the recording medium 30A. The toner image for developing an electrostatic charge image transferred to the recording medium 30A is fixed by the fixing device . On the other hand, the surface of the photoreceptor 12 after the electrostatic image development toner image has been transferred is cleaned by a cleaning blade 220 in a cleaning device 22, and then neutralized by a neutralization device .

[0161] [Developer] The developer according to the present embodiment contains at least the specific toner. The developer according to the present embodiment may be a one-component developer containing only the specific toner, or may be a two-component developer in which the specific toner is mixed with a carrier.

[0162] <Toner> The toner according to the present embodiment is configured to contain toner particles containing a binder resin and resin particles, and an external additive.

[0163] (toner particles) The toner particles contain at least a binder resin and resin particles. The toner particles contain a colorant, a release agent, and other additives as needed. In the following description, the resin particles to be internally added to the toner particles will be referred to as "internal resin particles" to distinguish them from the resin particles that serve as the binder resin used in the production of the toner particles.

[0164] -Binder resin- Examples of binder resins include homopolymers of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), and vinyl resins made of copolymers of two or more of these monomers. Examples of the binder resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin, mixtures of these with the vinyl resins, and graft polymers obtained by polymerizing vinyl monomers in the presence of these. These binder resins may be used alone or in combination of two or more.

[0165] The binder resin preferably contains an amorphous resin. The binder resin may contain a crystalline resin together with the amorphous resin. However, the mass ratio of the amorphous resin to the crystalline resin (crystalline resin / amorphous resin) is preferably 2 / 98 or more and 50 / 50 or less, more preferably 4 / 96 or more and 30 / 70 or less. Here, the term "amorphous resin" refers to a resin that, in thermal analysis measurement using differential scanning calorimetry (DSC), does not show a clear endothermic peak but only a stepwise endothermic change, is solid at room temperature, and becomes thermoplastic at a temperature equal to or higher than the glass transition temperature. On the other hand, a crystalline resin is one that shows a clear endothermic peak rather than a stepwise change in endothermic amount in differential scanning calorimetry (DSC). Specifically, for example, an amorphous resin refers to a resin whose half-value width exceeds 10°C or a resin in which no clear endothermic peak is observed, whereas a crystalline resin refers to a resin whose half-value width of the endothermic peak is 10°C or less when measured at a heating rate of 10°C / min.

[0166] The amorphous resin will be described. Examples of amorphous resins include known amorphous resins such as amorphous polyester resins, amorphous vinyl resins (e.g., styrene-acrylic resins), epoxy resins, polycarbonate resins, polyurethane resins, etc. Among these, amorphous polyester resins and amorphous vinyl resins (particularly styrene-acrylic resins) are preferred, and amorphous polyester resins are more preferred.

[0167] Amorphous polyester resin Examples of the amorphous polyester resin include a condensation polymer of a polycarboxylic acid and a polyhydric alcohol. Note that, as the amorphous polyester resin, a commercially available product or a synthesized product may be used.

[0168] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, and sebacic acid), alicyclic dicarboxylic acids (such as cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. The polycarboxylic acid may be a trivalent or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acids may be used alone or in combination of two or more.

[0169] 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, preferred polyhydric alcohols are aromatic diols and alicyclic diols, and more preferred are aromatic diols. As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. The polyhydric alcohols may be used alone or in combination of two or more.

[0170] The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 65°C or lower. The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, from the "extrapolated glass transition onset temperature" described in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0171] The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less. The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the amorphous polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). Molecular weight measurements by GPC are performed using a Tosoh GPC HLC-8120GPC measuring device and a Tosoh TSKgel SuperHM-M (15 cm) column in THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from the measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0172] The amorphous polyester resin can be obtained by a known manufacturing method, for example, by carrying out the reaction at a polymerization temperature of 180°C or higher and 230°C or lower, reducing the pressure in the reaction system as necessary, and removing water and alcohol generated during the condensation. If the raw material monomer is not soluble or compatible at the reaction temperature, a high-boiling solvent may be added as a solubilizer to dissolve it. In this case, the polycondensation reaction is carried out while distilling off the solubilizer. If a monomer with poor compatibility is present, it is advisable to first condense the poorly compatible monomer with the acid or alcohol to be polycondensed, and then polycondense the monomer with the main component.

[0173] The crystalline resin will now be described. Examples of the crystalline resin include known crystalline resins such as crystalline polyester resins and crystalline vinyl resins (e.g., polyalkylene resins, long-chain alkyl (meth)acrylate resins, etc.) Among these, crystalline polyester resins are preferred in terms of the mechanical strength and low-temperature fixability of the toner.

[0174] Crystalline polyester resin The crystalline polyester resin may be, for example, a polycondensate of a polycarboxylic acid and a polyhydric alcohol. Note that, as the crystalline polyester resin, a commercially available product or a synthesized product may be used. Here, the crystalline polyester resin is preferably a polycondensate using a polymerizable monomer having a linear aliphatic group rather than a polymerizable monomer having an aromatic group, since it easily forms a crystalline structure.

[0175] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2,6-dicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acid may be a tricarboxylic or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the tricarboxylic acid include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). As the polycarboxylic acid, a dicarboxylic acid having a sulfonic acid group and a dicarboxylic acid having an ethylenic double bond may be used in combination with these dicarboxylic acids. The polycarboxylic acids may be used alone or in combination of two or more.

[0176] Examples of polyhydric alcohols include aliphatic diols (for example, straight-chain aliphatic diols having 7 to 20 carbon atoms in the main chain). Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanedecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols. The polyhydric alcohol may be a trihydric or higher alcohol having a crosslinked or branched structure, such as glycerin, trimethylolethane, trimethylolpropane, or pentaerythritol, in combination with the diol. The polyhydric alcohols may be used alone or in combination of two or more.

[0177] Here, the polyhydric alcohol has an aliphatic diol content of 80 mol % or more, preferably 90 mol % or more.

[0178] The melting temperature of the crystalline polyester resin is preferably 50°C or higher and 100°C or lower, more preferably 55°C or higher and 90°C or lower, and even more preferably 60°C or higher and 85°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in the method for determining the melting temperature in JIS K7121-1987 "Method for measuring transition temperatures of plastics."

[0179] The weight average molecular weight (Mw) of the crystalline polyester resin is 6,000 or more and 35,000 or less. Below is preferred.

[0180] The crystalline polyester resin can be obtained by a known manufacturing method, for example, in the same manner as the amorphous polyester.

[0181] The content of the binder resin is, for example, preferably 40% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, and even more preferably 60% by mass to 85% by mass, based on the total mass of the toner particles.

[0182] -Internal resin particles- The internal resin particles have a storage modulus G' of 1 x 10 in the range of 23°C to 80°C in dynamic viscoelasticity measurement at a temperature rise of 2°C / min. 5 Pa or more 5×10 7 Resin particles having a viscosity of 0.1 Pa or less are preferred. The storage modulus G' of the internal resin particles in the range of 23°C to 80°C is 1 x 10 5 Pa or more 2×10 7 Pa or less, and 1×10 5 Pa or more 1×10 7 It is more preferable that the viscosity is 0.05 Pa or less. Internally-added resin particles having a storage modulus G' within the above range at temperatures from 23°C to 80°C have a high modulus of elasticity even at temperatures from 23°C to 80°C. Therefore, by incorporating internally-added resin particles having a storage modulus G' within the above range into toner particles, the toner particles have the property of controlling the surface hardness of the toner particles to an optimum level. Therefore, silica particles are appropriately liberated from the toner particles, and the external additives are more likely to penetrate into the contact area between the cleaning blade and the photosensitive member, which makes it easier to achieve both reduced wear on the cleaning blade and reduced wear on the inorganic protective layer of the electrophotographic photosensitive member.

[0183] The storage modulus G' of the internally added resin particles is measured as follows. Pressure is applied to the internally added resin particles to be measured to prepare a disk-shaped sample with a thickness of 2 mm and a diameter of 8 mm, which is used as the measurement sample. When measuring the internally added resin particles contained in toner particles, the internally added resin particles are removed from the toner particles before preparing the measurement sample. Examples of methods for removing the internally added resin particles from the toner particles include a method in which the toner particles are immersed in a solvent that dissolves the binder resin but not the internally added resin particles, and the internally added resin particles are removed by dissolving the binder resin in the solvent. The resulting disk-shaped sample for measurement is then sandwiched between parallel plates with a diameter of 8 mm, and the measurement temperature is raised from 23°C to 80°C at a rate of 2°C / min at a strain of 0.1 to 100%, and dynamic viscoelasticity measurement is performed under the following conditions: The storage modulus G' is determined from the curves of the storage modulus and loss modulus obtained by the measurement. -Measurement conditions- Measurement device: Rheometer ARES-G2 (manufactured by TA Instruments) Gap: Adjusted to 3mm Frequency: 1Hz

[0184] The internally added resin particles are preferably crosslinked resin particles. Here, the term "internal resin particles" refers to resin particles that have a bridge structure between specific atoms in the polymer structure contained in the resin particles.

[0185] By using crosslinked resin particles as the internally added resin particles, the storage modulus G' of the internally added resin particles in the temperature range of 23° C. or higher and 80° C. or lower tends to fall within the above range.

[0186] Examples of the crosslinked resin particles include crosslinked resin particles crosslinked by ionic bonds (ionically crosslinked resin particles), crosslinked resin particles crosslinked by covalent bonds (covalently crosslinked resin particles), etc. Among these, crosslinked resin particles crosslinked by covalent bonds are preferred.

[0187] Examples of resins used in the 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 copolymer resins thereof. These resins may be used alone or in combination of two or more types, as needed.

[0188] Of the above resins, styrene-(meth)acrylic copolymer resins are preferred as the resins used for the crosslinked resin particles. That is, styrene-(meth)acrylic copolymer resin particles are preferred as the crosslinked resin particles.

[0189] When the crosslinked resin particles are styrene-(meth)acrylic copolymer resin particles, the internally added resin particles tend to have a storage modulus G' within the range of 23° C. or higher and 80° C. or lower within the above range.

[0190] Examples of the styrene-(meth)acrylic copolymer resin include resins obtained by radical polymerization of the following styrene monomer and (meth)acrylic acid monomer.

[0191] Examples of styrene-based 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, etc. Among these, styrene and α-methylstyrene are preferred.

[0192] 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 of such acrylates include neopentyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, phenyl (meth)acrylate, biphenyl (meth)acrylate, diphenylethyl (meth)acrylate, t-butylphenyl (meth)acrylate, terphenyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, β-carboxyethyl (meth)acrylate, (meth)acrylonitrile, and (meth)acrylamide. Among these, n-butyl (meth)acrylate and β-carboxyethyl (meth)acrylate are preferred.

[0193] Examples of crosslinking agents for crosslinking the resin in the crosslinked resin particles include 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 trimesate, trivinyl trimesate, divinyl naphthalenedicarboxylate, and divinyl biphenylcarboxylate; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridinedicarboxylate; vinyl esters of unsaturated heterocyclic carboxylic acids such as vinyl pyromethane, vinyl furancarboxylate, vinyl pyrrole-2-carboxylate, and vinyl thiophenecarboxylate; and divinyl esters of butanediol diacrylate, butanediol dimethacrylate, hexanediol diacrylate, octanediol dimethacrylate, decanediol diacrylate, and dodecanediol dimethacrylate. Examples of suitable crosslinking agents include (meth)acrylic acid esters of branched or substituted polyhydric alcohols such as neopentyl glycol dimethacrylate and 2-hydroxy-1,3-diacryloxypropane; (meth)acrylic acid esters of branched or substituted polyhydric alcohols such as polyethylene glycol di(meth)acrylate, polypropylene polyethylene glycol di(meth)acrylates, and polyvinyl esters of polycarboxylic acids such as 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 adipate, divinyl pimelate, divinyl suberate, divinyl azelaate, divinyl sebacate, divinyl dodecanedioate, and divinyl brassylate. These crosslinking agents may be used singly or in combination of two or more.

[0194] When the internal resin particles are a polymer of a composition for forming internal resin particles containing a styrene-based monomer, a (meth)acrylic acid-based monomer, and a crosslinking agent, the viscoelasticity of the internal resin particles can 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 internal resin particles with a high storage modulus G'. The content of the crosslinking agent in the composition for forming internal resin particles is, for example, preferably 0.3 to 5.0 parts by mass, more preferably 0.5 to 2.5 parts by mass, and even more preferably 1.0 to 2.0 parts by mass, per 100 parts by mass of the total of the styrene-based monomer, the (meth)acrylic acid-based monomer, and the crosslinking agent.

[0195] The number average particle size of the internally added resin particles is preferably 60 nm or more and 300 nm or less, more preferably 100 nm or more and 200 nm or less, and even more preferably 130 nm or more and 170 nm or less. When the number-average particle diameter of the internal resin particles is 60 nm or more, the toner particles are more susceptible to the elasticity of the internal resin particles. Furthermore, the dispersibility of the internal resin particles in the toner particles is also improved. This results in the toner particles having an appropriate hardness. On the other hand, when the number-average particle diameter of the internal resin particles is 300 nm or less, the toner particles are prevented from becoming excessively hard. Therefore, when the number average particle diameter of the internally added resin particles is within the above range, the silica particles are easily released from the toner particles to an appropriate extent, which makes it easier to achieve both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member.

[0196] 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, JEM-1010 manufactured by JEOL Datum Co., Ltd. can be used. Hereinafter, a method for measuring the number average particle diameter of the internally added resin particles will be specifically described. Toner particles are cut into pieces about 0.3 μm thick using a microtome. The cross sections of the toner particles are photographed at 4,500x magnification using a transmission electron microscope, and the circular equivalent diameters of 1,000 internal resin particles dispersed in the toner particles are calculated from the cross-sectional areas of each, and the arithmetic mean of these is taken as the number-average particle diameter.

[0197] The content of the internal 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, based on the total mass of the toner particles. When the content of the internal resin particles is 2% by mass or more, the toner particles are easily affected by the elasticity of the internal resin particles and have an appropriate hardness, whereas when the content of the internal resin particles is 30% by mass or less, the toner particles are prevented from becoming excessively hard. Therefore, when the content of the internally added resin particles is within the above range, the silica particles are easily released from the toner particles to an appropriate extent, which makes it easier to achieve both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member.

[0198] -Coloring agent- Examples of colorants include carbon black, chrome yellow, Hansa Yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, Balkan orange, watch young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, lithol red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, and the like. Examples of the dye include various pigments such as phosphorus blue, chalco oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, and various dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes. The colorant may be used alone or in combination of two or more kinds.

[0199] The colorant may be surface-treated as needed, or may be used in combination with a dispersant. Furthermore, a plurality of colorants may be used in combination.

[0200] The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0201] -Mold release agent- Examples of release agents include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic or mineral / petroleum waxes such as montan wax, and ester waxes such as fatty acid esters and montanic acid esters, but are not limited thereto.

[0202] The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, and more preferably 60°C or higher and 100°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by using the "melting peak temperature" as described in the method for determining the melting temperature in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0203] The content of the release agent is, for example, preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0204] -Other additives- Examples of other additives include well-known additives such as magnetic materials, charge control agents, inorganic powders, etc. These additives are contained in the toner particles as internal additives.

[0205] -Relationship between the composition of toner particles- Difference (SP value (S) - SP value (R)) The difference between the solubility parameter SP value (S) of the internally added resin particles and the solubility parameter SP value (R) of the binder resin (SP value (S) - SP value (R)) is preferably -0.32 or more and -0.12 or less.

[0206] When the difference (SP value (S) - SP value (R)) is within the above range, the internally added resin particles are more likely to be dispersed in a nearly uniform state within the toner particles than 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 melt viscosity of the entire toner due to excessive mixing and dissolution of the internal resin particles and the binder resin when the toner is melted is suppressed compared to when the difference is greater than the above range. When the binder resin is a mixed resin, the solubility parameter of the resin with the highest content in the binder resin is taken as the SP value (R).

[0207] The difference (SP value (S) - SP value (R)) is more preferably -0.32 or more and -0.12 or less, and even more preferably -0.29 or more and -0.18 or less.

[0208] 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.

[0209] 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 3 ) 1 / 2 ) is calculated using the Okitsu method. The Okitsu method is described in detail in the Journal of the Adhesion Society of Japan, Vol. 29, No. 5 (1993).

[0210] Viscoelasticity of components excluding internal resin particles (excluded components) The storage modulus G' of the toner particles excluding the internal resin particles in the range of 23°C to 50°C is 1 x 10 8 Pa or more, and the storage modulus G' is 1 x 10 5 It is preferable that the temperature at which the toner particle density reaches less than 1 Pa is 65° C. or higher and 90° C. or lower. Hereinafter, the components excluding the internally added resin particles from the toner particles are also referred to as “excluded components”, and the storage modulus G′ of the toner particle density is 1×10 5 The temperature at which the storage modulus G' of an excluded component satisfies the above condition is also called the "specific elastic modulus attainment temperature." The excluded component, whose storage modulus G' satisfies the above condition, has a high elastic modulus at low temperatures and a low elastic modulus at temperatures between 65°C and 90°C. Therefore, if the storage modulus G' of an excluded component satisfies the above condition, the storage modulus G' will be 1 x 10 5 The silica particles are more easily liberated from the toner particles at a temperature of less than 90° C. than when the temperature exceeds 90° C. This makes it easier to achieve both reduced wear on the cleaning blade and reduced wear on the inorganic protective layer of the electrophotographic photosensitive member.

[0211] The storage modulus G' of the excluded components at temperatures between 23°C and 50°C is 1 x 10 8 Pa or more, and 1 × 10 8 Pa or more 1×10 9 Pa or less is more preferable, and 2×10 8 Pa or more 6×10 8 It is more preferable that the viscosity is 0.01 Pa or less.

[0212] The elastic modulus attainment temperature of the excluded components is preferably 65°C or higher and 90°C or lower, more preferably 68°C or higher and 80°C or lower, and even more preferably 70°C or higher and 75°C or lower.

[0213] The storage modulus G' of the excluded component is determined as follows. Specifically, first, the internally added resin particles are removed from the toner particles to extract only the removed components, and the removed components are then molded into a tablet shape at 25° C. using a press molding machine to prepare a measurement sample. Examples of a method for removing the internally added resin particles from the toner particles to extract only the removed components include a method in which the toner particles are immersed in a solvent that dissolves the binder resin but does not dissolve the internally added resin particles, and the removed components are extracted and extracted. The obtained measurement sample is then sandwiched between parallel plates with a diameter of 8 mm, and the measurement temperature is raised from 30°C to 150°C at a rate of 2°C / min at a strain of 0.1 to 100%, and dynamic viscoelasticity measurement is performed under the following conditions: The storage modulus G' is determined from the curves of the storage modulus and loss modulus obtained by the measurement. -Measurement conditions- Measurement device: Rheometer ARES-G2 (manufactured by TA Instruments) Measurement jig: 8mm parallel plate Gap: Adjusted to 3mm Frequency: 1Hz

[0214] -Characteristics of toner particles, etc.- The toner particles may be toner particles of a single layer structure, or may be toner particles of a so-called core-shell structure composed of a core part (core particle) and a coating layer (shell layer) that coats the core part. Here, the toner particles having a core-shell structure may be preferably composed of, for example, a core containing a binder resin, internal resin particles, and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing the binder resin and internal resin particles.

[0215] When the toner particles have a core-shell structure, it is preferable that the internal resin particles are contained in both the core particle and the shell layer. By containing the internal resin particles in both the core particle and the shell layer, the internal resin particles are contained in both the surface region and the central region of the toner particles, which further reduces the difference in gloss conditions.

[0216] 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.

[0217] The various average particle sizes and particle size distribution indices of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using an ISOTON-II (manufactured by Beckman Coulter). For the measurement, 0.5 mg to 50 mg of the sample to be measured is added to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant, and this is then added to 100 ml to 150 ml of the electrolyte. The electrolyte solution in which the sample was suspended was dispersed for 1 minute using an ultrasonic disperser, and then the Coulter Multi-Sized The particle size distribution of particles with a particle size range of 2 μm to 60 μm is measured using a 100 μm aperture with a Zirconia II. The number of particles sampled is 50,000. Based on the particle size distribution measured, cumulative distributions of volume and number are drawn for each divided particle size range (channel) from the smallest diameter side, and the particle size at 16% of the cumulative total is defined as the volume particle size D16v, the number particle size D16p, the particle size at 50% of the cumulative total as the volume average particle size D50v, the cumulative number average particle size D50p, and the particle size at 84% of the cumulative total as the volume particle size D84v and the number particle size D84p. Using these, the volumetric particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 , the number particle size distribution index (GSDp) is (D84p / D16p) 1 / 2 It is calculated as:

[0218] The average circularity of the toner particles is preferably 0.94 or more and 1.00 or less, and more preferably 0.95 or more and 0.98 or less.

[0219] The average circularity of toner particles is calculated by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle having the same projected area as the particle image) / (perimeter of the particle projected image)]. Specifically, this value is measured by the following method. First, the toner particles to be measured are sucked and collected, forming a flat flow, and a still image of the particles is captured by instantaneously activating a strobe light, and the particle image is analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation).The number of samples to be sampled when calculating the average circularity is 3,500. When the toner contains external additives, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additives have been removed.

[0220] (external additives) Examples of external additives include inorganic particles such as SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, KO, Na2O, ZrO2, CaO·SiO2, KO·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, and MgSO4.

[0221] The surfaces of inorganic particles as external additives are preferably subjected to a hydrophobic treatment. The hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, and aluminum coupling agents. These may be used alone or in combination of two or more. The amount of the hydrophobic treatment agent is usually, for example, 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the inorganic particles.

[0222] Examples of external additives include resin particles (resin particles such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), cleaning agents (for example, metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based polymers).

[0223] Here, the toner preferably contains silica particles as an external additive, and more preferably contains titanium oxide particles together with silica particles as an external additive. Silica particles have the property of being easily released from toner particles, and when used in combination with titanium oxide particles in particular, they have the property of being easily released from toner particles. This allows the external additive to easily penetrate into the contact area between the cleaning blade and the photosensitive member, thereby reducing friction between the cleaning blade and the electrophotographic photosensitive member, thereby making it easier to achieve both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member.

[0224] The amount of the external additive added is, for example, preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2.0% by mass or less, based on the toner particles. When the amount of external additive is 0.01% by mass or more, the amount of free external additive is prevented from becoming excessively small, whereas when the amount of external additive is 5% by mass or less, the amount of free external additive is prevented from becoming excessively large. This allows the external additive to easily penetrate into the contact area between the cleaning blade and the photosensitive member, thereby reducing friction between the cleaning blade and the electrophotographic photosensitive member, thereby making it easier to achieve both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member.

[0225] (Toner characteristics) - Viscoelasticity of toner - In the dynamic viscoelasticity measurement of the toner according to the present embodiment, when the loss tangent tanδ at a temperature of 90°C and a distortion of 1% is D1(90), the loss tangent tanδ at a temperature of 90°C and a distortion of 50% is D50(90), the loss tangent tanδ at a temperature of 150°C and a distortion of 1% is D1(150), and the loss tangent tanδ at a temperature of 150°C and a distortion 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, It is preferred 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 loss tangent relative to the change in strain at both 90°C and 150°C. Therefore, the toner has similar viscoelasticity at high temperatures with high strain and at low temperatures with low strain. This allows for stable and appropriate supply of external additives to the contact area between the cleaning blade and the photoreceptor. This facilitates achieving both reduced wear on the cleaning blade and reduced wear on the inorganic protective layer of the electrophotographic photoreceptor.

[0226] In the toner, D1(90), D50(90), D1(150), and D50(150) are each preferably 0.6 or more and 1.8 or less, more preferably 0.8 or more and 1.6 or less. When D1(90), D50(90), D1(150), and D50(150) are all within the above ranges, it becomes easier to achieve both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member.

[0227] The value of D50(150)-D1(150) in the toner is less than 1.5, preferably 1.2 or less, and more preferably 1.0 or less. When the value of D50(150)-D1(150) is within the above range, it becomes easier to achieve both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member. The lower limit of the value of D50(150)-D1(150) is not particularly limited.

[0228] The value of D50(90)-D1(90) in the toner is less than 0.5, preferably 0.4 or less, and more preferably 0.3 or less. When the value of D50(90)-D1(90) is in the above range, it becomes easier to achieve both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member. The lower limit of the value of D50(90)-D1(90) is not particularly limited.

[0229] The loss tangent of the toner is determined as follows. Specifically, a measurement sample is prepared by molding the toner to be measured into a tablet shape at room temperature (25°C) using a press molding machine. Then, using this measurement sample, dynamic viscoelasticity measurement is performed using a rheometer under the following conditions, and the loss tangent tanδ at a temperature of 90°C or 150°C and a strain of 1% or 50% is determined from the obtained curves of storage modulus and loss modulus, to obtain D1(90), D50(90), D1(150), and D50(150). -Measurement conditions- Measurement device: Rheometer ARES-G2 (manufactured by TA Instruments) Measurement jig: 8mm parallel plate Gap: Adjusted to 3mm Frequency: 1Hz

[0230] (Toner manufacturing method) Next, a method for producing the toner according to this embodiment will be described. The toner according to the exemplary embodiment can be obtained by producing toner particles and then externally adding an external additive to the toner particles, if necessary.

[0231] The toner particles may be produced by any of a dry production method (for example, a kneading and pulverization method) and a wet production method (for example, an aggregation and coalescence method, a suspension polymerization method, a dissolution and suspension method). The method for producing the toner particles is not particularly limited, and any well-known production method may be used. Among these, it is preferable to obtain toner particles by the aggregation and coalescence method.

[0232] Specifically, for example, when toner particles are produced by the aggregation and coalescence method, Toner particles are manufactured through the following steps: a step of preparing a resin particle dispersion in which resin particles that become the binder resin are dispersed, and a resin particle dispersion in which internally added resin particles become the internally added resin particles (resin particle dispersion preparation step); a step of aggregating resin particles (and other particles, if necessary) in the resin particle dispersion (in a dispersion after mixing other particle dispersions, if necessary) to form aggregated particles (aggregated particle formation step); and a step of heating the aggregated particle dispersion in which the aggregated particles are dispersed, fusing and coalescing the aggregated particles to form toner particles (fusion and coalescence step).

[0233] Each step will be described in detail below. In the following description, a method for obtaining toner particles containing a colorant and a release agent will be described, but the colorant and the release agent are used as needed. Of course, additives other than the colorant and the release agent may also be used.

[0234] -Resin particle dispersion preparation process- First, a resin particle dispersion in which resin particles serving as a binder resin are dispersed, as well as a colorant particle dispersion in which colorant particles are dispersed and a release agent particle dispersion in which release agent particles are dispersed are prepared.

[0235] Here, the resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0236] Examples of the dispersion medium used in the resin particle dispersion include aqueous media. Examples of aqueous media include water such as distilled water and ion-exchanged water, alcohols, etc. These may be used alone or in combination of two or more.

[0237] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly preferred. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants. The surfactants may be used alone or in combination of two or more.

[0238] In the resin particle dispersion, resin particles can be dispersed in a dispersion medium by a general dispersion method such as a rotary shear homogenizer, a ball mill having a medium, a sand mill, a dyno mill, etc. Depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion by, for example, a phase inversion emulsification method. The phase inversion emulsification method involves dissolving the resin to be dispersed in a hydrophobic organic solvent in which the resin is soluble, adding a base to the organic continuous phase (O phase) to neutralize it, and then adding an aqueous medium (W phase), thereby converting the resin from W / O to O / W (so-called phase inversion) and forming a discontinuous phase, and dispersing the resin in particulate form in the aqueous medium.

[0239] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably from 0.01 μm to 1 μm, more preferably from 0.08 μm to 0.8 μm, and even more preferably from 0.1 μm to 0.6 μm. The volume average particle size of the resin particles is measured using a particle size distribution obtained by measurement with a laser diffraction particle size distribution analyzer (e.g., LA-700 manufactured by Horiba, Ltd.), and the cumulative distribution for the volume of the divided particle size range (channel) is subtracted from the small particle size side, and the particle size at which the cumulative 50% of all particles is measured is defined as the volume average particle size D50v. The volume average particle sizes of particles in other dispersions are also measured in the same way.

[0240] The content of resin particles contained in the resin particle dispersion is, for example, preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass.

[0241] Note that, for example, a colorant particle dispersion and a release agent particle dispersion are also prepared in the same manner as the resin particle dispersion. That is, the volume average particle size, dispersion medium, dispersion method, and particle content of the particles in the resin particle dispersion are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0242] Preparation of internal resin particle dispersion The dispersion of internally added resin particles can be prepared by known methods such as emulsion polymerization, melt kneading using a Banbury mixer or kneader, suspension polymerization, and spray drying, with emulsion polymerization being preferred.

[0243] From the viewpoint of setting the storage modulus G' and loss tangent tanδ of the internally added resin particles within preferred ranges, it is preferred to use a styrene-based monomer and a (meth)acrylic acid-based monomer as the monomers and polymerize them in the presence of a crosslinking agent. In addition, in the production of the internally added resin particles, it is preferable to carry out emulsion polymerization multiple times. The method for producing the internally added resin particles will be described in more detail below.

[0244] The method for preparing the dispersion of internally added resin particles is as follows: a step of obtaining an emulsion containing a monomer, a crosslinking agent, a surfactant, and water (emulsion preparation step); a step of adding a polymerization initiator to the emulsion and heating the emulsion to polymerize the monomers (first emulsion polymerization step); It is preferable to include a step (second emulsion polymerization step) of adding an emulsion containing a monomer and a crosslinking agent to the reaction solution after the first emulsion polymerization step and heating the mixture to polymerize the monomer.

[0245] -Emulsion preparation process- This is a step of obtaining an emulsion containing a monomer, 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 agitators equipped with propeller-type, anchor-type, paddle-type, or turbine-type agitating blades, static mixers such as static mixers, homogenizers, Examples include rotor-stator type emulsifiers such as Clearmix, mill type emulsifiers with grinding function, high pressure emulsifiers such as Manton-Gaulin pressure emulsifiers, high pressure nozzle type emulsifiers that generate cavitation under high pressure, high pressure collision type emulsifiers such as Microfluidizers that apply shear force by causing liquids to collide with each other under high pressure, ultrasonic emulsifiers that generate cavitation using ultrasound, and membrane emulsifiers that emulsify uniformly through fine pores.

[0246] As the monomer, it is preferable to use a styrene-based monomer and a (meth)acrylic acid-based monomer. As the crosslinking agent, those already mentioned above are applicable.

[0247] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants. Among these, anionic surfactants are preferred. The surfactants may be used alone or in combination of two or more.

[0248] The emulsion may contain a chain transfer agent. There are no particular limitations on the chain transfer agent, but a compound 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.

[0249] From the viewpoint of setting the storage modulus G' of the internally added resin particles within a preferred range, the mass ratio of the styrene-based monomer to the (meth)acrylic acid-based monomer in the emulsion (styrene-based monomer / (meth)acrylic acid-based monomer) is preferably 0.2 or more and 1.1 or less. In addition, from the viewpoint of keeping the storage modulus G' of the internally added resin particles within a preferred range, the content of the crosslinking agent relative to the entire emulsion is preferably 0.5% by mass or more and 3% by mass or less.

[0250] -First emulsion polymerization process- This is a process in which a polymerization initiator is added to the emulsion and heated to polymerize the monomers. Here, when carrying out the polymerization, it is preferable to stir the emulsion (reaction solution) containing the polymerization initiator with a stirrer. Examples of the agitator include rotary agitators equipped with propeller-type, anchor-type, paddle-type, or turbine-type agitator blades. As the polymerization initiator, ammonium persulfate is preferably used. When a polymerization initiator is used, the viscoelasticity of the resulting internally added resin particles may be controlled by adjusting the amount of the polymerization initiator added. For example, by reducing the amount of the polymerization initiator added, resin particles with a high storage modulus G' are more likely to be obtained.

[0251] -Second emulsion polymerization process- This is a step in which an emulsion containing a monomer is added to the reaction solution after the first emulsion polymerization step, and the mixture is heated to polymerize the monomer. During the polymerization, it is preferable to stir the reaction solution in the same manner as in the first emulsion polymerization step. In this step, the viscoelasticity of the resulting internally-added resin particles may be controlled by adjusting the time taken to add the emulsion containing the monomer. For example, extending the time taken to add the emulsion containing the monomer makes it easier to obtain resin particles with a high storage modulus G'. The time taken to add the emulsion containing the monomer can be, for example, in the range of 2 hours to 5 hours. In this step, the viscoelasticity of the resulting internally-added resin particles may be controlled by adjusting the temperature at which the reaction solution is stirred. For example, lowering the temperature at which the reaction solution is stirred makes it easier to obtain internally-added resin particles with a high storage modulus G'. The temperature at which the reaction solution is stirred may be, for example, in the range of 55°C or higher and 75°C or lower. The emulsion containing the monomer is preferably obtained by emulsifying the monomer, surfactant, and water using an emulsifier, for example.

[0252] -Agglomerated particle formation process- Next, the colorant particle dispersion, the release agent particle dispersion, and the internally added resin particle dispersion are mixed together with the resin particle dispersion. Then, in the mixed dispersion, the resin particles, colorant particles, release agent particles, and internally added resin particles are hetero-aggregated to form aggregated particles containing the resin particles, colorant particles, release agent particles, and internally added resin particles and having a diameter close to the diameter of the target toner particles.

[0253] Specifically, for example, an aggregating agent is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to be acidic (for example, a pH of 2 or more and 5 or less), and a dispersion stabilizer is added as necessary. After that, the mixed dispersion is heated to the glass transition temperature of the resin particles (specifically, for example, a temperature of the glass transition temperature of the resin particles -30°C or more and the glass transition temperature -10°C or less), and the particles dispersed in the mixed dispersion are aggregated to form aggregated particles. In the aggregate particle formation step, for example, the mixed dispersion may be stirred with a rotary shear homogenizer, the above-mentioned aggregating agent may be added at room temperature (e.g., 25°C), the pH of the mixed dispersion may be adjusted to an acidic value (e.g., pH 2 or more and 5 or less), a dispersion stabilizer may be added as needed, and then the above-mentioned heating may be carried out.

[0254] In this step, the temperature of the mixed dispersion liquid when adding the aggregating agent may be adjusted to control the dispersion state of the internally added resin particles in the resulting toner particles. For example, lowering the temperature of the mixed dispersion liquid improves the dispersibility of the internally added resin particles. The temperature of the mixed dispersion liquid may be, for example, in the range of 5°C or higher and 40°C or lower. In this step, the dispersion state of the internally added resin particles in the toner particles obtained may be controlled by adjusting the stirring speed after adding the aggregating agent. For example, by increasing the stirring speed after adding the aggregating agent, the dispersibility of the internally added resin particles becomes good.

[0255] Examples of the flocculant include a surfactant having a polarity opposite to that of the surfactant used as the dispersant added to the mixed dispersion, an inorganic metal salt, and a divalent or higher metal complex. In particular, when a metal complex is used as the flocculant, the amount of surfactant used can be reduced and the charging characteristics can be improved. If necessary, an additive that forms a complex or a similar bond with the metal ions of the flocculant may be used, and a chelating agent is preferably used as this additive.

[0256] Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, as well as inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. The chelating agent may be a water-soluble chelating agent, such as hydroxycarboxylic acid (e.g., tartaric acid, citric acid, gluconic acid), iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), etc. The amount of the chelating agent added is, for example, preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, per 100 parts by mass of the resin particles.

[0257] -Fusion / unification process- Next, the aggregated particle dispersion liquid in which the aggregated particles are dispersed is heated, for example, to a temperature equal to or higher than the glass transition temperature of the resin particles (for example, a temperature 10 to 30° C. higher than the glass transition temperature of the resin particles). The aggregated particles are then fused and coalesced to form toner particles.

[0258] Through the above steps, toner particles are obtained. After obtaining an aggregated particle dispersion in which aggregated particles are dispersed, the toner particles may be produced through the following steps: a step of further mixing the aggregated particle dispersion, a resin particle dispersion in which resin particles are dispersed, and an internally-added resin particle dispersion in which internally-added resin particles are dispersed, and aggregating the aggregated particles so that the resin particles and the internally-added resin particles adhere to the surfaces of the aggregated particles to form second aggregated particles; and a step of heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and coalesce the second aggregated particles to form toner particles having a core / shell structure.

[0259] In the step of forming the second aggregated particles, the addition of the resin particle dispersion and the internally-added resin particle dispersion and the adhesion of the resin particles and the internally-added resin particles to the surfaces of the aggregated particles may be repeated multiple times, thereby obtaining toner particles in which the internally-added resin particles are evenly contained in both the surface region and the center region of the toner particles.

[0260] After the fusion and coalescence process, the toner particles formed in the solution are subjected to a known washing process, a solid-liquid separation process, and a drying process to obtain dry toner particles. In the washing step, it is preferable to carry out sufficient replacement washing with ion-exchanged water from the viewpoint of electrostatic chargeability. Furthermore, the solid-liquid separation step is not particularly limited, but from the viewpoint of productivity, it is preferable to carry out suction filtration, pressure filtration, etc. Furthermore, in the drying step, there is no particular limitation on the method, but from the viewpoint of productivity, it is preferable to carry out freeze drying, flash drying, fluidized drying, vibration-type fluidized drying, etc.

[0261] The toner according to this embodiment is produced by, for example, adding an external additive to the obtained dry toner particles and mixing them. The mixing can be carried out using, for example, a V blender, a Henschel mixer, a Loedige mixer, or the like. Furthermore, if necessary, coarse particles may be removed from the toner using a vibrating sieve, an air sieve, or the like.

[0262] <Electrostatic image developer> The electrostatic image developer according to this embodiment contains at least the toner according to this embodiment. The electrostatic image developer according to this embodiment may be a one-component developer containing only the toner according to this embodiment, or may be a two-component developer containing the toner mixed with a carrier.

[0263] The carrier is not particularly limited, and examples thereof include known carriers, such as coated carriers in which the surface of a core material made of magnetic powder is coated with a coating resin, magnetic powder dispersion carriers in which magnetic powder is dispersed and blended in a matrix resin, and resin-impregnated carriers in which porous magnetic powder is impregnated with a resin. The magnetic powder dispersion type carrier and the resin impregnated type carrier may be a carrier in which the constituent particles of the carrier are used as a core material and are coated with a coating resin.

[0264] Examples of magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0265] Examples of coating resins and matrix resins include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid ester copolymer, straight silicone resins containing organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenolic resins, and epoxy resins. The coating resin and matrix resin may contain conductive particles and other additives. Good too. Examples of conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0266] Here, the method of coating the surface of the core material with a coating resin includes a method of coating with a solution for forming a coating layer in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be selected taking into consideration the coating resin to be used, its applicability, etc. Specific resin coating methods include an immersion method in which the core material is immersed in a solution for forming a coating layer, a spray method in which the solution for forming a coating layer is sprayed onto the surface of the core material, a fluidized bed method in which the solution for forming a coating layer is sprayed onto the core material while it is suspended in flowing air, and a kneader coater method in which the core material of the carrier and the solution for forming a coating layer are mixed in a kneader coater and the solvent is removed.

[0267] In the two-component developer, the mixing ratio (mass ratio) of toner to carrier is preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100. [Example]

[0268] Examples of the present invention will be described below, but the present invention is not limited to the following examples. In the following description, unless otherwise specified, all "parts" and "%" are based on mass.

[0269] [Preparation of Internally Added Resin Particle Dispersion] <Preparation of Internally Added Resin Particle Dispersion 1> Styrene: 47.9 parts n-Butyl acrylate: 51.8 parts β-Carboxyethyl acrylate: 0.3 parts Anionic surfactant (Dowfax2A1, manufactured by The Dow Chemical Company): 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 thereto, followed by dispersion and emulsification in a flask to prepare an emulsion. Next, 1.3 parts of an anionic surfactant (Dowfax2A1, manufactured by The Dow Chemical Company) was dissolved in 90 parts of ion-exchanged water, and 1 part of the emulsion was added thereto. Further, 10 parts of ion-exchanged water in which 5.4 parts of ammonium persulfate had been dissolved was added. Thereafter, the remainder of the emulsion was added over 180 minutes, and the atmosphere in the flask was replaced with nitrogen. The solution in the flask was then heated to 65°C in an oil bath while stirring, and emulsion polymerization was continued for 500 minutes, after which an internally added resin particle dispersion 1 was obtained with a solid content adjusted to 24.5% by mass.

[0270] <Preparation of Internally Added Resin Particle Dispersions 2 to 10, C1 and C2> Internally-added resin particle dispersions 2 to 10 and C1 to C2 were obtained in the same manner as for internally-added resin particle dispersion 1, except that the amount of styrene added, the amount of n-butyl acrylate added, the amount of acrylic acid added, the amount of β-carboxyethyl acrylate added, the total amount of anionic surfactant added, the amount of butanediol diacrylate added (crosslinking agent in the table), the amount of ammonium peroxide added, the temperature heated in the oil bath (polymerization temperature in the table), the time when the remainder of the emulsion was added (addition time in the table), and the time during which emulsion polymerization was continued after heating (retention time in the table) were as shown in Table 1.

[0271] [Table 1]

[0272] The resin particles contained in the obtained internally added resin particle dispersion and the comparative resin particle dispersion were measured for the minimum value ("G' (small)" in the table) and maximum value ("G' (large)" in the table) of the storage modulus G' at 23°C or higher and 80°C or lower, the number average particle size, and the SP value (S) using the above-mentioned methods. The results are shown in Table 2.

[0273] [Table 2]

[0274] [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 mole adduct: 26 parts Bisphenol A propylene oxide 2 mole adduct: 542 parts The above materials were charged into a reaction vessel equipped with a stirrer, a nitrogen inlet tube, a temperature sensor, and a rectification column, the temperature was raised to 190°C over 1 hour, and 1.2 parts of dibutyltin oxide was added per 100 parts of the above materials. The temperature was raised to 240°C over 6 hours while distilling off the produced water, and the dehydration condensation reaction was continued for 3 hours while maintaining the temperature at 240°C, after which the reaction product was cooled.

[0275] The reaction product was transferred in a molten state to a Cavitron CD1010 (manufactured by Eurotech) at a rate of 100 g per minute. At the same time, a separately prepared ammonia water with a concentration of 0.37 mass % was heated to 120°C in a heat exchanger and transferred to the Cavitron CD1010 at a rate of 0.1 L per minute. The rotor rotation speed was 60 Hz, and the pressure was 5 kg / cm. 2 The Cavitron CD1010 was operated under the conditions shown above to obtain a resin particle dispersion in which resin particles of an amorphous polyester resin having a volume average particle size of 175 nm were dispersed. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain Amorphous Resin Particle Dispersion 1. The SP value (R) of the obtained amorphous polyester resin was 9.43.

[0276] <Preparation of Amorphous Resin Particle Dispersion 2> Styrene: 72 parts n-Butyl acrylate: 27 parts β-Carboxyethyl acrylate: 1.3 parts Dodecanethiol: 2 parts The mixture obtained by mixing and dissolving the above materials was dispersed and emulsified in a flask with a surfactant solution prepared by dissolving 1.2 parts by weight of an anionic surfactant (TaycaPower, manufactured by Tayca Corporation) in 100 parts by weight of ion-exchanged water. Next, an aqueous solution prepared by dissolving 6 parts by weight of ammonium persulfate in 50 parts by weight of ion-exchanged water was added to the flask over a period of 20 minutes while stirring. After nitrogen substitution, the contents of the flask were heated in an oil bath with stirring until the temperature reached 75°C, and the temperature was maintained at 75°C for 4 hours to continue emulsion polymerization. This resulted in a resin particle dispersion containing amorphous styrene-acrylic resin particles with a volume-average particle size of 160 nm and a weight-average molecular weight of 56,000. Ion-exchanged water was added to this resin particle dispersion to adjust the solids content to 31.4% by weight, resulting in amorphous resin particle dispersion 2. The SP value (R) of the obtained amorphous styrene acrylic resin was 9.14.

[0277] <Preparation of Crystalline Resin Particle Dispersion> 1,10-dodecanedioic acid: 225 parts 1,6-Hexanediol: 143 parts The above materials were charged into a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and distillation column. The temperature was raised to 160°C over 1 hour, and 0.8 parts by mass of dibutyltin oxide was added. The temperature was raised to 180°C over 6 hours while distilling off the produced water, and the dehydration condensation reaction was continued for 5 hours while maintaining the temperature at 180°C. The temperature was then gradually raised to 230°C under reduced pressure, and stirring was continued for 2 hours while maintaining the temperature at 230°C. The reaction product was then cooled. After cooling, solid-liquid separation was performed, and the solid was dried to obtain a crystalline polyester resin.

[0278] Crystalline polyester resin: 100 parts Methyl ethyl ketone: 40 parts Isopropyl alcohol: 30 parts 10% ammonia solution: 6 parts The above materials were added to a 3-liter jacketed reactor (Tokyo Rikakikai Co., Ltd.: BJ-30N) equipped with a condenser, thermometer, water dripper, and anchor blade. The resin was dissolved by stirring at 100 rpm while maintaining the temperature at 80°C in a water-circulating thermostatic bath. The water-circulating thermostatic bath was then set to 50°C, and a total of 400 parts of ion-exchanged water maintained at 50°C was added dropwise at a rate of 7 parts by mass / min to induce phase inversion, yielding an emulsion. 576 parts by mass of the resulting emulsion and 500 parts by mass of ion-exchanged water were placed in a 2-liter recovery flask and placed in an evaporator (Tokyo Rikakikai Co., Ltd.) equipped with a vacuum control unit via a trap bulb. The recovery flask was heated in a 60°C hot water bath while rotating, and the pressure was reduced to 7 kPa, taking care to avoid bumping, to remove the solvent. The volume average particle size (D50v) of the resin particles in this dispersion was 185 nm. Thereafter, ion-exchanged water was added to obtain a crystalline resin particle dispersion liquid with a solid content concentration of 22.1% by mass.

[0279] <Preparation of Colorant Dispersion> Cyan pigment (Dainichi Seikagaku Co., Ltd., Pigment Blue 15:3 (copper phthalocyanine)): 98 parts Anionic surfactant (Tayca Power manufactured by Tayca Corporation): 2 parts Ion-exchanged water: 420 parts The above ingredients were mixed and dissolved, and dispersed for 10 minutes using a homogenizer (IKA Ultra Turrax), to obtain a colorant dispersion having a median particle size of 164 nm and a solid content of 21.1% by mass.

[0280] <Preparation of release agent dispersion> Synthetic wax (Nippon Seiro Co., Ltd., FNP92, melting temperature Tw: 92°C): 50 parts Anionic surfactant (Tayca Power manufactured by Tayca Corporation): 1 part Ion-exchanged water: 200 parts The above materials were mixed and heated to 130°C, dispersed using a homogenizer (IKA Ultra Turrax T50), and then dispersed in a Manton-Gaulin high-pressure homogenizer (Gaulin ) to obtain a release agent dispersion liquid (solid content: 20% by mass) in which release agent particles are dispersed. The volume average particle size of the release agent particles is 214 nm.

[0281] <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 (Dowfax2A1, manufactured by The Dow Chemical Company): 4.8 parts The above raw materials, the liquid temperature of which was adjusted to 10°C, were placed in a 3 L cylindrical stainless steel container and dispersed and mixed 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 as a flocculant was gradually added dropwise, and the homogenizer was rotated at 10,000 rpm for 10 minutes to disperse and mix, thereby obtaining a raw material dispersion.

[0282] The raw material dispersion was then transferred to a polymerization kettle equipped with a stirrer using two paddle stirrers and a thermometer, and the stirring speed was set to 550 rpm and heating was started using a mantle heater to promote the growth of aggregated particles at 40°C. The pH of the raw material dispersion was controlled in the range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M aqueous sodium hydroxide. The pH was maintained within this range for approximately 2 hours to form aggregated particles. Next, a dispersion liquid obtained by mixing 1:21 parts of the amorphous resin particle dispersion liquid and 1:8 parts of the internally added resin particle dispersion liquid was added, and the mixture was maintained for 60 minutes, allowing the binder resin particles and the internally added resin particles to adhere to the surfaces of the aggregated particles. The temperature was further increased to 53°C, and then 1:21 parts of the amorphous resin particle dispersion liquid was added, and the mixture was maintained for 60 minutes, allowing the binder resin particles to adhere to the surfaces of the aggregated particles.

[0283] The aggregated particles were adjusted while checking the particle size and shape using an optical microscope and a Multisizer 3. Thereafter, the pH was adjusted to 7.8 using a 5% aqueous sodium hydroxide solution, and the mixture was maintained for 15 minutes. Thereafter, the pH was increased to 8.0 to fuse the aggregated particles, and the temperature was then raised 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 through a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles 1.

[0284] 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.

[0285] <Toners 2 to 11, Toners C1 to C2> Toners 2 to 11 and toners C1 to C2 were obtained in the same manner as toner 1, except that instead of internal resin particle dispersion 1, the types of internal resin particle dispersions shown in Table 3 were used in amounts such that the content of resin particles (i.e., internal resin particles) relative to the total toner particles would be the value shown in Table 3.

[0286] <Toner 12-14> Toners 12 to 14 were obtained in the same manner as Toner 1, except that the amount of crystalline resin particle dispersion added was adjusted so that the content of the crystalline resin relative to the total binder resin would be the value shown in Table 3.

[0287] <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 Dispersion of the type shown in Table 3 was used in the amount shown in Table 3.

[0288] <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.

[0289] <Toner 17> Toner 17 was obtained in the same manner as Toner 1, except that the amount of the crystalline resin particle dispersion added was adjusted so that the content of the crystalline resin relative to the total binder resin would be the value shown in Table 3.

[0290] <Toner 18> Toner 18 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 all 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 all binder resins was the value shown in Table 3.

[0291] <Toner 19> Toner 19 was obtained in the same manner as Toner 1, except that the pH during the fusion of the aggregated particles was changed from 8.0 to 9.0.

[0292] <Toner 20> Toner 20 was obtained in the same manner as Toner 1, except that the pH during the fusion of the aggregated particles was changed from 8.0 to 5.5.

[0293] <Toner 21> Toner 21 was obtained in the same manner as Toner 1, except that the amount of internal resin particle dispersion 1 was used such that the content of internal resin particles relative to the total toner particles was the value shown in Table 3, and the pH during fusion of the aggregated particles was changed from 8.0 to 9.5.

[0294] <Toner 22> Toner 22 was obtained in the same manner as Toner 1, except that the amount of internal resin particle dispersion 1 was used such that the content of internal resin particles relative to the total toner particles would be the value shown in Table 3, and the pH during fusion of the aggregated particles was changed from 8.0 to 6.0.

[0295] <Toner 23-27> Toners 23 to 27 were obtained in the same manner as Toner 1, except that instead of internally-added resin particle dispersion 1, the types of internally-added resin particle dispersions shown in Table 3 were used in amounts such that the content of internally-added resin particles relative to the total toner particles would be 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 would be the value shown in Table 3.

[0296] <Toner 28-31> Toners 28 to 31 were obtained in the same manner as Toner 1, except that the following amount of dimethyl silicone oil-treated silica particles (RY200 manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts of the obtained toner particles and mixed using a Henschel mixer to obtain the toner. Toner 28:0.005 parts Toner 29:0.1 parts Toner 30:5 parts Toner 31:5.1 parts

[0297] <Toner 32> Toner 32 was obtained in the same manner as Toner 1, except that 100 parts of the obtained toner particles, 0.6 parts of dimethyl silicone oil-treated silica particles (RY200 manufactured by Nippon Aerosil Co., Ltd.), and 0.1 parts of titanium oxide particles (JMT150-B manufactured by Teika Co., Ltd.) were mixed using a Henschel mixer.

[0298] <Toner 33> Toner 32 was obtained in the same manner as Toner 1, except that 100 parts of the obtained toner particles and 0.7 parts of titanium oxide particles (JMT150-B manufactured by Teika Corporation) were mixed using a Henschel mixer.

[0299] <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 (Dowfax2A1, manufactured by The Dow Chemical Company): 4.8 parts The above raw materials were adjusted to a liquid temperature of 30°C and placed in a 3L cylindrical stainless steel container. They were then homogenized at 4000 rpm using a homogenizer (IKA Ultra Turrax T50) while applying shear force. 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 speed of 4000 rpm to obtain a raw material dispersion.

[0300] The raw material dispersion was then transferred to a polymerization kettle equipped with a stirrer using two paddle stirrers and a thermometer, and the stirring speed was set to 550 rpm and heating was started using a mantle heater to promote the growth of aggregated particles at 40°C. The pH of the raw material dispersion was controlled in the range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M aqueous sodium hydroxide. The pH was maintained within this range for approximately 2 hours to form aggregated particles. Next, a dispersion liquid obtained by mixing 21 parts of amorphous resin particle dispersion liquid and 8 parts of internally added resin particle dispersion liquid was added, and the mixture was maintained for 60 minutes, allowing the binder resin particles and internally added resin particles to adhere to the surfaces of the aggregated particles. The temperature was further increased to 53°C, and then 21 parts of amorphous resin particle dispersion liquid was added, and the mixture was maintained for 60 minutes, allowing the binder resin particles to adhere to the surfaces of the aggregated particles.

[0301] The aggregated particles were adjusted while checking the particle size and shape using an optical microscope and a Multisizer 3. Thereafter, the pH was adjusted to 7.8 using a 5% aqueous sodium hydroxide solution, and the mixture was maintained for 15 minutes. The pH was then increased to 8.0 to fuse the aggregated particles, and the temperature was then raised 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 through a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles C3.

[0302] 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.

[0303] <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 (Dowfax2A1, manufactured by The Dow Chemical Company): 4.8 parts The above raw materials, the liquid temperature of which was adjusted to 30°C, were placed in a 3 L cylindrical stainless steel container and dispersed and mixed 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 speed of 4000 rpm to obtain a raw material dispersion.

[0304] The raw material dispersion was then transferred to a polymerization kettle equipped with a stirrer using two paddle stirrers and a thermometer, and the stirring speed was set to 550 rpm and heating was started using a mantle heater to promote the growth of aggregated particles at 40°C. The pH of the raw material dispersion was controlled in the range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M aqueous sodium hydroxide. The pH was maintained within this range for approximately 2 hours to form aggregated particles. Next, 1:42 parts of the amorphous resin particle dispersion liquid was added and the mixture was kept for 60 minutes, so that the resin particles of the binder resin were adhered to the surfaces of the aggregated particles.

[0305] The size and shape of the particles were checked using an optical microscope and a Multisizer 3, and the aggregated particles were adjusted. Thereafter, the pH was adjusted to 7.8 using a 5% aqueous sodium hydroxide solution, and the mixture was maintained for 15 minutes. The pH was then increased to 8.0 to fuse the aggregated particles, and the temperature was then raised 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 through a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles C4.

[0306] 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.

[0307] <Comparative example 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 (Dowfax2A1, manufactured by The Dow Chemical Company): 4.8 parts The above raw materials, the liquid temperature of which was adjusted to 30°C, were placed in a 3 L cylindrical stainless steel container and dispersed and mixed 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 speed of 4000 rpm to obtain a raw material dispersion.

[0308] The raw material dispersion was then transferred to a polymerization kettle equipped with a stirrer using two paddle stirrers and a thermometer, and the stirring speed was set to 550 rpm and heating was started using a mantle heater to promote the growth of aggregated particles at 40°C. The pH of the raw material dispersion was controlled in the range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M aqueous sodium hydroxide. The pH was maintained within this range for approximately 2 hours to form aggregated particles. Next, a dispersion liquid obtained by mixing 1:42 parts of the amorphous resin particle dispersion liquid and 1:41 parts of the internally added resin particle dispersion liquid was divided into two halves, and each halved was added in two portions and held for 60 minutes to allow the binder resin particles and the internally added resin particles to adhere to the surfaces of the aggregated particles.

[0309] The aggregated particles were adjusted while checking the particle size and shape using an optical microscope and a Multisizer 3. Thereafter, the pH was adjusted to 7.8 using a 5% aqueous sodium hydroxide solution, and the mixture was maintained for 15 minutes. Thereafter, the pH was increased to 8.0 to fuse the aggregated particles, and the temperature was raised 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 through a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles C5.

[0310] 100 parts of the obtained toner particles and 0.7 parts of dimethylsilicone oil-treated silica particles (RY200 manufactured by Nippon Aerosil Co., Ltd.) were mixed in a Henschel mixer to obtain toner C5.

[0311] 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 (%)" 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). Table 3 also shows the results of determining the storage modulus G' (indicated as "G' (Pa)" in the table) of the excluded components in the range of 23°C or higher and 50°C or lower, and the temperature at which the specific modulus of elasticity is reached (indicated as "attained temperature (°C)" in the table) using the method described above. Furthermore, the values ​​of D1(90), D50(90), D1(150), D50(150), D50(150) - D1(150) ("difference (150)" in the table), D50(90) - D1(90) ("difference (90)" in the table), storage modulus G' in the range of 30°C or higher and 50°C or lower ("G' (Pa)" in the table), and difference (SP value (S) - SP value (R)) ("SP value difference" in the table) for the obtained toner were determined by the above-mentioned methods, and the results are also shown in Table 3.

[0312] [Table 3-1]

[0313] [Table 3-2]

[0314] [Table 3-3]

[0315] <Preparation of Developers 1 to 33 and Developers C1 to C5> Developers 1 to 33 and C to C5 were obtained by mixing 8 parts of the obtained toner with 100 parts of the carrier described below.

[0316] -Creating a carrier- Ferrite particles (average particle size 50 μm) 100 parts Toluene 14 parts Styrene / methyl methacrylate copolymer (copolymerization ratio 15 / 85) 3 parts Carbon black 0.2 parts The above components except for the ferrite particles were dispersed in a sand mill to prepare a dispersion liquid, and this dispersion liquid was placed in a vacuum degassing kneader together with the ferrite particles, and the mixture was stirred under reduced pressure and dried to obtain a carrier.

[0317] <Preparation of photoreceptor> (Photoconductor 1) - Formation of undercoat layer - 100 parts by mass of zinc oxide (average particle size: 70 nm, manufactured by Teika Corporation) was mixed with 500 parts by mass of toluene and stirred, and 1.5 parts by mass of a silane coupling agent (trade name: KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) was added and stirred for 2 hours. Thereafter, the toluene was distilled off under reduced pressure, and the mixture was baked at 150°C for 2 hours.

[0318] 60 parts by mass of the obtained surface-treated zinc oxide, 15 parts by mass of a curing agent (blocked isocyanate, product name: Sumidur BL3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.), and 15 parts by mass of a butyral resin (product name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) were dissolved in 85 parts by mass of methyl ethyl ketone, and 25 parts by mass of methyl ethyl ketone were mixed with this to obtain a liquid to be treated.

[0319] Next, a horizontal media mill disperser (KDL-PILOT type, Dynomill, manufactured by Shinmaru Enterprises) was used to carry out a dispersion treatment according to the following procedure. The cylinder of the disperser and the stirring mill were made of ceramics whose main component was zirconia. 1 mm diameter glass beads (Hi-Bee D20, manufactured by Ohara Inc.) were placed in the cylinder at a bulk filling rate of 80% by volume, and dispersion treatment was carried out by a circulation method with the stirring mill's peripheral speed set to 8 m / min and the flow rate of the liquid to be treated set to 1000 mL / min. A magnetic gear pump was used to transport the liquid to be treated.

[0320] In the dispersion process, a portion of the liquid to be treated was sampled after a predetermined time had elapsed, and the transmittance during film formation was measured. Specifically, the liquid to be treated was applied to a glass plate to a film thickness of 20 μm, and cured at 150°C for 2 hours to form a coating. The transmittance at a wavelength of 950 nm was then measured using a spectrophotometer (U-2000, manufactured by Hitachi). The dispersion process was terminated when this transmittance (value for a film thickness of 20 nm) exceeded 70%.

[0321] To the dispersion thus obtained, 0.005 parts by mass of dioctyltin dilaurate as a catalyst and 0.01 parts by mass of silicone oil (product name: SH29PA, manufactured by Toray Dow Corning Silicones Co., Ltd.) were added to prepare a coating liquid for an undercoat layer. This coating liquid was applied by dip coating to an aluminum substrate having a diameter of 84 mm, a length of 340 mm, and a thickness of 1 mm, and then dried and cured at 160°C for 100 minutes to form an undercoat layer with a thickness of 20 μm.

[0322] -Formation of organic photosensitive layer- An organic photosensitive layer composed of a charge generation layer and a charge transport layer was formed on an undercoat layer as follows. First, a mixture consisting of 15 parts by weight of chlorogallium phthalocyanine (charge generation material) having diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.4°, 16.6°, 25.5°, and 28.3° in an X-ray diffraction spectrum using CuKα radiation, 10 parts by weight of vinyl chloride-vinyl acetate copolymer resin (trade name: VMCH, manufactured by Nippon Unicar Co., Ltd.) as a binder resin, and 300 parts by weight of n-butyl alcohol was dispersed in a sand mill using 1 mm diameter glass beads for 4 hours to obtain a charge generation layer coating liquid. The resulting dispersion was dip-coated on the undercoat layer and dried to form a charge generation layer with a thickness of 0.2 μm.

[0323] Furthermore, 4 parts by weight of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1']biphenyl-4,4'-diamine and 6 parts by weight of bisphenol Z polycarbonate resin (viscosity average molecular weight: 40,000) were dissolved in 80 parts by weight of chlorobenzene to obtain a coating liquid for a charge transport layer. This coating liquid was applied to the charge generation layer and dried at 130°C for 40 minutes to form a charge transport layer with a thickness of 25 μm, thereby obtaining an organic photoreceptor (i.e., an uncoated photoreceptor).

[0324] - Formation of inorganic protective layer - Next, an inorganic protective layer was formed on the uncoated photoreceptor by plasma CVD. A Si substrate (5 mm × 10 mm) for preparing a reference sample was attached to the uncoated photoreceptor with adhesive tape, and the uncoated photoreceptor was introduced into the plasma CVD apparatus shown in Figure 3. The inside of the vacuum chamber 132 was heated to a pressure of 1 × 10 -2The chamber was evacuated to a vacuum of 10 Pa. Next, hydrogen gas at a flow rate of 200 sccm, He-diluted oxygen (4%) at a flow rate of 5 sccm, and hydrogen-diluted trimethylgallium (approximately 10%) at a flow rate of 5 sccm were supplied from gas supply pipe 134 via mass flow controller 136 to vacuum chamber 132, and the conductance valve was adjusted to bring the pressure inside vacuum chamber 132 to 10 Pa. A 13.56 MHz radio wave was set to an output of 80 W using high-frequency power supply 158 and matching box 156, and matching was performed using a tuner, with the reflected wave set to 0 W, causing a discharge from discharge electrode 154. In this state, film formation was performed for 73 minutes while rotating the uncoated photoreceptor at a speed of 20 rpm, forming an inorganic protective layer on the organic protective layer. The hydrogen-diluted trimethylgallium gas was supplied by bubbling hydrogen as a carrier gas into trimethylgallium maintained at 0° C. The obtained photoreceptor was left in an environment at a temperature of 20° C. for 24 hours.

[0325] By the above operations, a photoreceptor 1 was obtained. The water contact angle of the inorganic protective layer surface was 99°.

[0326] (Photoconductors 2~4, 101~103) Photoreceptors 2 to 6 and 101 to 103 were obtained under the conditions shown in Table 4 in the same manner as for photoreceptor 1, except that the hydrogen gas flow rate, He diluted oxygen flow rate, and hydrogen diluted trimethylgallium flow rate were changed.

[0327] [Table 4]

[0328] <Examples 1 to 47 and Comparative Examples 1 to 7> The developer, photoreceptor, and cleaning blade in the combination shown in Table 5 were installed in an image forming apparatus "ApeosPort / DocuCentre-VI C7771" manufactured by FUJIFILM Business Innovation Co., Ltd. The device conditions were as shown in Table 5. The image forming apparatus thus obtained was used to carry out the following evaluations. Comparative Example 6 is an example in which developer 34 in which the content of internally added resin particles in the toner of developer 24 was finely adjusted to the content shown in Table 5 was used. Similarly, Comparative Example 7 is an example in which Developer 35 was used, in which the content of internally added resin particles in the toner of Developer 25 was finely adjusted to the content shown in Table 5.

[0329] <Cleaning blade wear> Using the image forming apparatus described above, 30,000 sheets of A4 paper were output under conditions of a high temperature and high humidity environment (30°C, 85%) and an image density of 1%. The amount of wear at the tip of the cleaning blade was evaluated by observing the cross-sectional profile with a laser microscope VK-9500 manufactured by Keyence Corporation, measuring the cross-sectional area of ​​the worn portion, and evaluating the amount of wear according to the following criteria. A: Blade wear amount <1.7μm2 B: 1.7 μm 2 ≦Blade wear amount≦2.0μm 2 C: 2.0 μm 2 <Blade wear amount≦2.3μm 2 D: 2.3 μm 2 <Blade wear amount≦3.0μm 2 E: 3.0 μm 2 <Blade wear amount

[0330] <Wear of photoconductor> Using the image forming apparatus described above, 30,000 sheets of A4 paper were output under conditions of a high temperature and high humidity environment (30°C, 85%) and an image density of 1%. The thickness of the inorganic protective layer was measured before and after the image formation using an eddy current film thickness measuring instrument, and the difference was calculated as the amount of wear of the photoreceptor, and evaluated according to the following criteria. A: Photoconductor wear amount <0.6 μm B: 0.6 μm≦photoconductor wear amount≦0.8 μm C: 0.8μm<Photoconductor wear amount≦1.2μm D: 1.2 μm≦photoconductor wear amount≦1.6 μm E: 1.6 μm < photoconductor wear

[0331] [Table 5-1]

[0332] [Table 5-2]

[0333] From the above results, it can be seen that the image forming apparatus of this embodiment achieves both reduced wear of the cleaning blade and reduced wear of the inorganic protective layer of the electrophotographic photosensitive member compared to the image forming apparatus of the comparative example. [Explanation of symbols]

[0334] 10 Image forming device 12 Photoreceptor 14 Charging member 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 Media 31 Transcription device 36 Control device 220 Cleaning Blade

Claims

1. an electrophotographic photoreceptor having an inorganic protective layer containing oxygen, hydrogen, and a Group 13 element as an outermost surface layer; a charging device that contacts and charges the surface of the electrophotographic photosensitive member; an electrostatic image forming device for forming an electrostatic image on the charged surface of the electrophotographic photosensitive member; a developing device that contains a developer containing a toner and develops an electrostatic image formed on the surface of the electrophotographic photosensitive member with the developer to form a toner image; a cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photosensitive member; a transfer device that transfers the toner image onto a surface of a recording medium; Equipped with the toner comprises toner particles containing a binder resin and resin particles, and an external additive, and the content of the resin particles relative to the total amount of the toner particles is 2% by mass or more and 30% by mass or less; the inorganic protective layer has a sum of the constituent ratios of the oxygen, the hydrogen, and the Group 13 element with respect to the total amount of elements constituting the inorganic protective layer of 0.95 or more, and an elemental constituent ratio R of the oxygen to the Group 13 element (oxygen / Group 13 element) of 0.8 or more and 1.9 or less; a ratio (W / R) of the content W of the resin particles to the elemental composition ratio R of oxygen to the Group 13 elements (oxygen / Group 13 elements) satisfies 1.05≦W / R≦37.5; Image forming device.

2. 2. The image forming apparatus according to claim 1, wherein a ratio (W / R) of the content W of the resin particles to the elemental composition ratio R of the oxygen to the Group 13 element (oxygen / Group 13 element) satisfies 6.99≦W / R≦12.

23.

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

4. In a dynamic viscoelasticity measurement of the resin particles at a temperature rise of 2°C / min, the storage modulus G' in the range of 23°C to 80°C is 1 x 10 ５ Pa or more 5×10 ７ 4. The image forming apparatus according to claim 1, wherein the pressure is 0.01 Pa or less.

5. In a dynamic viscoelasticity measurement of the components of the toner particles excluding the resin particles at a temperature rise of 2° C. / min, the storage modulus G′ in the range of 23° C. to 50° C. is 1×10 ８ Pa or more, and the storage modulus G' is 1×10 ５ 5. The image forming apparatus according to claim 4, wherein the temperature at which the pressure reaches less than Pa is 65[deg.] C. or more and 90[deg.] C. or less.

6. In the dynamic viscoelasticity measurement of the toner, when the loss tangent tanδ at a temperature of 90°C and a distortion of 1% is D1(90), the loss tangent tanδ at a temperature of 90°C and a distortion of 50% is D50(90), the loss tangent tanδ at a temperature of 150°C and a distortion of 1% is D1(150), and the loss tangent tanδ at a temperature of 150°C and a distortion 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; 6. The image forming apparatus according to claim 1, wherein a value of D50(90)-D1(90) is less than 0.

5.

7. 7. The image forming apparatus according to claim 1, wherein the resin particles are crosslinked resin particles.

8. 8. The image forming apparatus according to claim 7, wherein the crosslinked resin particles are styrene (meth)acrylic resin particles.

9. 9. The image forming apparatus according to claim 1, wherein the toner contains silica particles as the external additive.

10. The image forming apparatus according to claim 9 , wherein the toner contains titanium oxide particles as the external additive together with the silica particles.

11. 11. The image forming apparatus according to claim 1, wherein the content of the external additive is 0.01% by mass or more and 5% by mass or less with respect to the toner particles.

12. 12. The image forming apparatus according to claim 1, wherein the Group 13 element in the inorganic protective layer is gallium.

13. 13. The image forming apparatus according to claim 1, wherein the inorganic protective layer has a water contact angle of 95° or more and 100° or less.

14. The image forming apparatus according to any one of claims 1 to 13, wherein a contact portion of the cleaning blade that comes into contact with the electrophotographic photosensitive member is made of a member having a 100% modulus at 23°C of 4 MPa or more and 18 MPa or less.

15. an electrophotographic photoreceptor having an inorganic protective layer containing oxygen, hydrogen, and a Group 13 element as an outermost surface layer; a developing device that contains a developer containing a toner and develops an electrostatic latent image formed on the surface of the electrophotographic photosensitive member with the developer to form a toner image; a cleaning device having a cleaning blade for cleaning the surface of the electrophotographic photosensitive member; Equipped with the toner comprises toner particles containing a binder resin and resin particles, and an external additive, and the content of the resin particles is 2% by mass or more and 30% by mass or less with respect to the total amount of the toner particles; the inorganic protective layer has a sum of the constituent ratios of the oxygen, the hydrogen, and the Group 13 element with respect to the total amount of elements constituting the inorganic protective layer of 0.95 or more, and an elemental constituent ratio R of the oxygen to the Group 13 element (oxygen / Group 13 element) of 0.8 or more and 1.9 or less; a ratio (W / R) of the content W of the resin particles to the elemental composition ratio R of oxygen to the Group 13 elements (oxygen / Group 13 elements) satisfies 1.05≦W / R≦37.5; A process cartridge that is detachably attached to an image forming apparatus.

Images