Image forming apparatus and process cartridge

Abstract

The present invention provides an image forming apparatus that offers good cleaning performance at high temperature, high humidity, and low image density, as well as at low temperature, low humidity, and high image density, thereby reducing wear on the photoreceptor. [Solution] The photosensitive layer of the photoreceptor contains a polyester resin having a dicarboxylic acid unit (A) of the following formula (A) and a diol unit (B) of the following formula (B), and the contact portion of the cleaning blade with the photoreceptor has an impregnated and cured layer of a composition containing an isocyanate compound and at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers. JPEG2026143156000045.jpg42105

Description

[Technical Field]

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

[0002] In image forming devices using the electrophotographic method (such as photocopiers, facsimile machines, and printers), a toner image formed on the surface of an electrophotographic photoreceptor is transferred to the surface of a recording medium and fixed onto the recording medium to form an image. Furthermore, since toner remains on the surface of the electrophotographic photoreceptor after the toner image is transferred, a cleaning blade is placed there to remove the residual toner.

[0003] For example, Patent Document 1 discloses "a cleaning member containing urethane rubber, characterized in that the urethane rubber has an annular structure in which fluorine atoms are directly bonded." Patent Document 2 describes an image forming apparatus comprising a photoreceptor and a cleaning blade having an elastic member that contacts the surface of the photoreceptor to remove deposits adhering to the surface of the photoreceptor, wherein the photoreceptor comprises a conductive support and a photosensitive layer and a surface layer sequentially laminated on the conductive support, the surface layer comprising a binder resin and particles, and the Martens hardness of the surface layer being 150 N / mm². 2 More than 180N / mm 2 An image forming apparatus is disclosed, characterized in that the elastic power is less than 35% or more and less than 45%, and the cleaning blade comprises an elastic member having a base layer and a surface layer, the surface layer having a tip ridge portion, and the surface layer having a domain having a polysiloxane structure with an average dispersion diameter of 0.1 μm or more and 5.0 μm or less in a region from the surface including the tip ridge portion of the elastic member to a depth of 100 μm. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-42160 [Patent Document 2] Japanese Patent Publication No. 2022-176575 [Overview of the project] [Problems that the invention aims to solve]

[0005] Conventionally, an electrophotographic photoreceptor having a photosensitive layer forming its surface, a charging device for charging the surface of the electrophotographic photoreceptor, an electrostatic image forming device for forming an electrostatic image on the charged surface of the electrophotographic photoreceptor, a developing device containing a developer and developing the electrostatic image formed on the surface of the electrophotographic photoreceptor as a toner image using the developer, a transfer device for transferring the toner image formed on the surface of the electrophotographic photoreceptor to the surface of a recording medium, and a cleaning device having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans at least residual toner particles from the surface of the electrophotographic photoreceptor. An image forming apparatus equipped with (hereinafter also referred to as "specific image forming apparatus") is known.

[0006] The object of the present invention is to provide an image forming apparatus that, compared to a specific image forming apparatus in which the photosensitive layer of the electrophotographic photoreceptor contains only polycarbonate resin, or in which the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor does not contain at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers, has good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image forming when repeatedly forming low-image-density images in a high-temperature, high-humidity environment and when repeatedly forming high-image-density images in a low-temperature, low-humidity environment. [Means for solving the problem]

[0007] <1> An electrophotographic photoreceptor having a photosensitive layer that constitutes its surface, A charging device for charging the surface of the electrophotographic photoreceptor, A static charge image forming apparatus for forming a static charge image on the surface of the charged electrophotographic photoreceptor, A developing device that accommodates a developer and develops an electrostatic charge image formed on the surface of the electrophotographic photosensitive member with the developer into a toner image, a transfer device that transfers the toner image formed on the surface of the electrophotographic photosensitive member onto a surface of a recording medium, a cleaning device that has a cleaning blade in contact with the surface of the electrophotographic photosensitive member and at least cleans residual toner particles on the surface of the electrophotographic photosensitive member, comprising: wherein the photosensitive layer in the electrophotographic photosensitive member contains a polyester resin (1) having a dicarboxylic acid unit (A) represented by the following formula (A) and a diol unit (B) represented by the following formula (B), an image forming apparatus wherein a contact portion of the cleaning blade that contacts the electrophotographic photosensitive member has an impregnated cured layer of a composition containing an isocyanate compound and at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers.

Chemical Formula

[0008] <1> According to the disclosure, compared to a specific image forming apparatus in which the photosensitive layer of the electrophotographic photoreceptor contains only polycarbonate resin, or in which the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor does not contain at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers, the provided image forming apparatus offers good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image forming when repeatedly forming low-image-density images in a high-temperature, high-humidity environment and when repeatedly forming high-image-density images in a low-temperature, low-humidity environment.

[0009] <2> According to the disclosure, compared to a case where the ratio of the total amount of F and Si present within 200 nm from the surface of the contact portion that contacts the electrophotographic photoreceptor to the total amount A present within 5 μm from the surface of the contact portion that contacts the electrophotographic photoreceptor is less than 75%, an image forming apparatus is provided that exhibits good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image formation when repeatedly forming low-image-density images in a high-temperature, high-humidity environment and when repeatedly forming high-image-density images in a low-temperature, low-humidity environment. <3> According to the disclosure, compared to cases where the ratio of the total amount B of F and Si to the total amount A of F and Si is less than 85% or more than 95%, an image forming apparatus is provided that offers good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image forming when low image density images are repeatedly formed in a high-temperature, high-humidity environment and when high image density images are repeatedly formed in a low-temperature, low-humidity environment. <4> According to the disclosure, compared to the case where the total amount of F and Si C present on the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is less than 15 atm%, an image forming apparatus is provided that offers good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image forming conditions, whether repeatedly forming low-image-density images in a high-temperature, high-humidity environment or repeatedly forming high-image-density images in a low-temperature, low-humidity environment. <5> According to the disclosure, compared to the case where the total amount D of F and Si located 50 nm from the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is less than 0.3 atm%, an image forming apparatus is provided that exhibits good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image formation when repeatedly forming low-image-density images in a high-temperature, high-humidity environment and when repeatedly forming high-image-density images in a low-temperature, low-humidity environment. <6> According to the disclosure, compared to cases where the 100% modulus at 23°C of the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is less than 5 MPa or more than 23 MPa, an image forming apparatus is provided that offers good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image formation when repeatedly forming low-image-density images in a high-temperature, high-humidity environment and when repeatedly forming high-image-density images in a low-temperature, low-humidity environment.

[0010] <7> According to the disclosure, compared to the case where the photosensitive layer of the electrophotographic photoreceptor contains a polyester resin (1) having dicarboxylic acid units represented by (A1) and diol units represented by (B5), an image forming apparatus is provided that has good cleaning properties and reduces wear of the electrophotographic photoreceptor, whether the image is repeatedly formed in a high-temperature, high-humidity environment with low image density or repeatedly formed in a low-temperature, low-humidity environment with high image density. <8> According to the disclosure, compared to a polyester resin having dicarboxylic acid units represented by (A2) and diol units represented by (B1), the provided image forming apparatus offers good cleaning properties and reduces wear on the electrophotographic photoreceptor in both image formation situations, whether repeatedly forming low-image-density images in a high-temperature, high-humidity environment or repeatedly forming high-image-density images in a low-temperature, low-humidity environment. <9> According to the disclosure, a process cartridge is provided that, compared to cases where the photosensitive layer of the electrophotographic photoreceptor contains only polycarbonate resin, or where the contact portion of the cleaning blade that contacts the surface of the electrophotographic photoreceptor does not contain at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers, has good cleaning performance and reduces wear of the electrophotographic photoreceptor, whether the image is repeatedly formed in a high-temperature, high-humidity environment with low image density or repeatedly formed in a low-temperature, low-humidity environment with high image density. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing an example of an image forming apparatus according to this embodiment. [Figure 2] This is a partial cross-sectional view showing an example of the layer structure of an electrophotographic photoreceptor. [Figure 3] This is a partial cross-sectional view showing an example of the layer structure of an electrophotographic photoreceptor. [Modes for carrying out the invention]

[0012] The embodiments of this disclosure are described below. These descriptions and embodiments are illustrative and do not limit the scope of the embodiments.

[0013] In this disclosure, the numerical range indicated using "~" represents a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values ​​shown in the examples.

[0014] In this disclosure, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, provided that their objectives are achieved.

[0015] When embodiments are described in this disclosure with reference to the drawings, the configuration of such embodiments is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each figure are conceptual, and the relative relationships between the components are not limited thereto.

[0016] In this disclosure, each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition in this disclosure, if there are multiple types of the substance corresponding to each component in the composition, it means the total amount of those multiple types of substances present in the composition unless otherwise specified. In this disclosure, each component may contain multiple types of particles. If multiple types of particles corresponding to each component are present in the composition, the particle size of each component refers to the value for a mixture of such multiple types of particles present in the composition, unless otherwise specified.

[0017] In this disclosure, alkyl groups include linear, branched, and cyclic alkyl groups unless otherwise specified.

[0018] In this disclosure, organic groups, aromatic rings, linking groups, alkyl groups, aryl groups, aralkyl groups, alkoxy groups, and aryloxy groups may have hydrogen atoms substituted by halogen atoms.

[0019] In this disclosure, the electrophotographic photoreceptor is also referred to as the "photoreceptor." The cleaning blade is also sometimes referred to as the "blade." The part of the cleaning blade that contacts the surface of the electrophotographic photoreceptor is also called the "blade tip." A high-temperature, high-humidity environment refers to, for example, an environment with a temperature of 28°C and a relative humidity of 80%. A low-temperature, low-humidity environment refers to, for example, an environment with a temperature of 10°C and a relative humidity of 15%. High image density refers to, for example, an image density of 10% to 25%. Low image density refers to an image density of, for example, 0.1% to 1%. Image density refers to the ratio of the area occupied by the formed image to the total area of ​​the recording medium's surface (i.e., the image-forming surface).

[0020] [Image forming apparatus] The image forming apparatus according to this embodiment comprises: an electrophotographic photoreceptor having a photosensitive layer constituting its surface; a charging device for charging the surface of the electrophotographic photoreceptor; an electrostatic image forming apparatus for forming an electrostatic image on the charged surface of the electrophotographic photoreceptor; a developing device for containing a developer and developing the electrostatic image formed on the surface of the electrophotographic photoreceptor as a toner image using the developer; a transfer device for transferring the toner image formed on the surface of the electrophotographic photoreceptor to the surface of a recording medium; and a cleaning device having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans at least residual toner particles from the surface of the electrophotographic photoreceptor. Furthermore, the photosensitive layer in the electrophotographic photoreceptor contains a polyester resin (1) having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B). On the other hand, the contact portion of the cleaning blade that comes into contact with the electrophotographic photoreceptor has an impregnated and cured layer of a composition comprising an isocyanate compound and at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers.

[0021] The image forming apparatus according to this embodiment, with the above configuration, exhibits good cleaning performance and reduces wear on the electrophotographic photoreceptor, regardless of whether it is repeatedly forming low-image-density images in a high-temperature, high-humidity environment or repeatedly forming high-image-density images in a low-temperature, low-humidity environment. The reason for this is presumed to be as follows.

[0022] When repeatedly forming low-image-density images in a high-temperature, high-humidity environment, the amount of discharge products generated on the photoreceptor surface increases significantly, leading to insufficient supply of toner additives that provide lubrication to the contact area between the blade and the photoreceptor. This, in turn, promotes increased friction between the blade and the photoreceptor. Under high-friction conditions, excessive retraction of the blade tip or uneven, localized retraction along the longitudinal direction of the blade tip may occur. As a result, blade curling, toner leakage, photoreceptor wear, and instability of blade tip behavior worsen. To increase friction between the blade and the photoreceptor, applying lubricating particles to the surface of the photoreceptor or increasing the modulus of the blade are effective measures. However, when these measures are implemented, if high-image-density images are repeatedly formed in a low-temperature, low-humidity environment, the amount of discharge product generated on the photoreceptor surface decreases significantly, and the supply of lubricating toner additives to the contact area between the blade and the photoreceptor becomes excessive. As a result, the reduction of friction between the blade and the photoreceptor is excessively promoted. In excessively low-friction conditions, the amount of retraction at the blade tip is insufficient, resulting in uneven, localized retraction along the longitudinal direction of the blade tip. This worsens toner penetration. Thus, in both image formation processes—whether repeatedly forming low-image-density images in a high-temperature, high-humidity environment or repeatedly forming high-image-density images in a low-temperature, low-humidity environment—it is difficult to achieve good cleaning performance while simultaneously reducing wear on the electrophotographic photoreceptor.

[0023] In contrast, in the image forming apparatus according to this embodiment, the photosensitive layer of the photoreceptor contains a polyester resin (1) having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B). As a result, even when high-image-density images are repeatedly formed in a low-temperature, low-humidity environment, the extreme reduction in friction between the blade and the photoreceptor can be reduced, and an appropriate friction state can be achieved. This is thought to be because filming (i.e., adhesion of developer components) is suppressed, and the contact area (i.e., nip) between the blade that cleans the photoreceptor and the photoreceptor is stabilized. Furthermore, by reducing the extreme reduction in friction, an appropriate amount of retraction of the blade tip necessary for cleaning can be secured, improving cleaning performance. In addition, the photosensitive layer containing the polyester resin (1) has increased durability and improved abrasion resistance.

[0024] In addition, the image forming apparatus according to this embodiment applies a blade to the tip of the blade having an impregnated and cured layer of a composition comprising an isocyanate compound and at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers. This results in a higher modulus at the blade tip and moderately low friction between the blade and the photoreceptor. As a result, even when repeatedly forming low-image-density images in high-temperature, high-humidity environments, excessive retraction of the blade tip or uneven, localized retraction of the blade tip in the longitudinal direction can be suppressed. Consequently, blade curling, toner leakage, photoreceptor wear, and instability of blade tip behavior can be suppressed.

[0025] From the above, it is presumed that the image forming apparatus according to this embodiment will have good cleaning properties and reduce wear on the electrophotographic photoreceptor, whether the image is repeatedly formed in a high-temperature, high-humidity environment with low image density, or repeatedly formed in a low-temperature, low-humidity environment with high image density.

[0026] Here, the image forming apparatus according to this embodiment may be a well-known image forming apparatus such as a direct transfer apparatus that directly transfers a toner image formed on the surface of a photoreceptor to a recording medium; an intermediate transfer apparatus that first transfers a toner image formed on the surface of a photoreceptor to the surface of an intermediate transfer body, and secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; or an apparatus equipped with a static elimination device that irradiates the surface of the photoreceptor with static elimination light to eliminate static charge after the transfer of the toner image and before charging. In the case of an intermediate transfer method apparatus, the transfer apparatus may be configured to include, for example, an intermediate transfer body on which a toner image is transferred; a primary transfer apparatus that first transfers the toner image formed on the surface of the photoreceptor to the surface of the intermediate transfer body; and a secondary transfer apparatus that secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

[0027] In the image forming apparatus according to this embodiment, the portion including at least a photoreceptor and a cleaning device may constitute a unit for the image forming apparatus and may be a cartridge structure (process cartridge) that can be attached to and detached from the image forming apparatus. The process cartridge according to this embodiment is not limited to the above configuration comprising an electrophotographic photoreceptor and a cleaning device, but may also include, as necessary, at least one selected from other means such as a charging device, an electrostatic image forming device, a developing device, and a transfer device.

[0028] The following is an example of an image forming apparatus according to this embodiment, but it is not limited to this example. The main parts shown in the figures will be described, and other parts will not be explained.

[0029] Figure 1 is a schematic diagram showing an example of an image forming apparatus according to this embodiment. The image forming apparatus 10 according to this embodiment includes a photoreceptor 12, as shown in Figure 1. The photoreceptor 12 is cylindrical and connected to a drive unit 27 such as a motor via a drive force transmission member (not shown) such as a gear, and is rotationally driven by the drive unit 27 around a rotation axis indicated by a black dot. In the example shown in Figure 1, the photoreceptor 12 is rotationally driven in the direction of arrow A.

[0030] Around the photoreceptor 12, for example, a charging device 15, an electrostatic image forming device 16, a developing device 18, a transfer device 31, a cleaning device 22, and a static elimination device 24 are arranged in order along the rotational direction of the photoreceptor 12. The image forming apparatus 10 also includes a fixing device 26 having a fixing member 26A and a pressing member 26B positioned in contact with the fixing member 26A. The image forming apparatus 10 also has a control device 36 that controls the operation of each device (each part). The unit including the photoreceptor 12, charging device 15, electrostatic image forming device 16, developing device 18, transfer device 31, and cleaning device 22 corresponds to the image forming unit.

[0031] In the image forming apparatus 10, at least the photoreceptor 12 and the cleaning device 22 may be provided as a process cartridge.

[0032] The following describes the various components of the image forming apparatus according to this embodiment.

[0033] <Electrophotographic photoconductor> The photoreceptor 12 has a photosensitive layer that constitutes its surface. In other words, the photosensitive layer is a layer placed on the outermost surface of the electrophotographic photoreceptor and constitutes the surface of the photoreceptor 12. Furthermore, the photosensitive layer constituting the surface includes a polyester resin (1) having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B) described later. The photosensitive layer in the photoreceptor 12 may be a stacked photosensitive layer having a charge generation layer and a charge transport layer, or it may be a single-layer photosensitive layer. In other words, the photosensitive layer that constitutes the surface and contains polyester resin (1) is either a charge transport layer in a multilayer photosensitive layer or a single-layer photosensitive layer.

[0034] The photoreceptor 12 has a conductive substrate in addition to the photosensitive layer (i.e., a multilayer photosensitive layer or a single-layer photosensitive layer). Furthermore, the electrophotographic photoreceptor may further include other layers (e.g., an undercoat layer, an intermediate layer) as needed, in addition to the conductive substrate and the photosensitive layer.

[0035] Figure 2 is a schematic partial cross-sectional view showing an example of the layer structure of a photoreceptor. The photoreceptor 12A shown in Figure 2 has a stacked photoreceptor layer. The photoreceptor 12A has a structure in which a base layer 2, a charge generation layer 3, and a charge transport layer 4 are stacked in this order on a conductive substrate 1, and the charge generation layer 3 and the charge transport layer 4 constitute the photoreceptor layer 5 (a so-called functionally separated photoreceptor layer). The photoreceptor 12A may have an intermediate layer (not shown) between the base layer 2 and the charge generation layer 3.

[0036] Figure 3 is a schematic partial cross-sectional view showing an example of the layer structure of a photoreceptor. The photoreceptor 12B shown in Figure 3 has a single-layer photosensitive layer. The photoreceptor 12B has a structure in which an undercoat layer 2 and a single-layer photosensitive layer 5 are stacked in this order on a conductive substrate 1. The photoreceptor 10B may have an intermediate layer (not shown) between the undercoat layer 2 and the single-layer photosensitive layer 5.

[0037] [Polyester resin (1)] The polyester resin (1) is included in the photosensitive layer that constitutes the surface as a binder resin. Specifically, if the photosensitive layer is a multilayer photosensitive layer, the charge transport layer that constitutes the surface contains the polyester resin (1). Also, if the photosensitive layer is a single-layer photosensitive layer, the single-layer photosensitive layer contains the polyester resin (1). The polyester resin (1) has at least a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B). The polyester resin (1) may also contain other dicarboxylic acid units other than the dicarboxylic acid unit (A). The polyester resin (1) may also contain other diol units other than the diol unit (B).

[0038] The dicarboxylic acid unit (A) is a constituent unit represented by the following formula (A).

[0039] [ka]

[0040] In equation (A), Ar A1 and Ar A2Each of these is an aromatic ring which may independently have substituents, L A is a single bond or a divalent linking group, n A1 It is 0, 1, or 2.

[0041] Ar A1 The aromatic ring may be monocyclic or polycyclic. Examples of aromatic rings include benzene rings, naphthalene rings, anthracene rings, and phenanthrene rings, with benzene rings and naphthalene rings being preferred.

[0042] Ar A1 The hydrogen atoms on the aromatic ring may be substituted with alkyl groups, aryl groups, aralkyl groups, alkoxy groups, aryloxy groups, halogen atoms, etc. A1 When the aromatic ring is substituted, preferred substituents are alkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 12 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms.

[0043] Ar A2 The aromatic ring may be monocyclic or polycyclic. Examples of aromatic rings include benzene rings, naphthalene rings, anthracene rings, and phenanthrene rings, with benzene rings and naphthalene rings being preferred.

[0044] Ar A2 The hydrogen atoms on the aromatic ring may be substituted with alkyl groups, aryl groups, aralkyl groups, alkoxy groups, aryloxy groups, halogen atoms, etc. A2 When the aromatic ring is substituted, preferred substituents are alkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 12 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms.

[0045] L A When it is a divalent linking group, the divalent linking group can be, for example, an oxygen atom, a sulfur atom, -C(Ra 1 )(Ra 2 )- is one example. Here, Ra 1 and Ra 2Each of these is independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, Ra 1 and Ra 2 These may be bonded together to form a cyclic alkyl group.

[0046] Ra 1 and Ra 2 The alkyl group having 1 to 10 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 or 2.

[0047] Ra 1 and Ra 2 The aryl group having 6 to 12 carbon atoms may be monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 to 10, and more preferably 6.

[0048] Ra 1 and Ra 2 The alkyl group in the aralkyl group having 7 to 20 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group in the aralkyl group having 7 to 20 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2. Ra 1 and Ra 2 The aryl group in the aralkyl group having 7 to 20 carbon atoms may be monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 to 10, and more preferably 6.

[0049] The dicarboxylic acid unit (A) preferably includes at least one selected from the group consisting of a dicarboxylic acid unit (A1) represented by the following formula (A1), a dicarboxylic acid unit (A2) represented by the following formula (A2), a dicarboxylic acid unit (A3) represented by the following formula (A3), and a dicarboxylic acid unit (A4) represented by the following formula (A4).

[0050] [ka]

[0051] In equation (A1), n 101 n is an integer between 0 and 4, and 101 Individual Ra 101 Each of these is independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. n 101 It is preferably 0, 1, or 2, more preferably 0 or 1, and even more preferably 0.

[0052] [ka]

[0053] In equation (A2), n 201 and n 202 Each of these is an independent integer between 0 and 4, and n 201 Individual Ra 201 and n 202 Individual Ra 202 Each of these is independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. n 201 It is preferably 0, 1, or 2, more preferably 0 or 1, and even more preferably 0. n 202 It is preferably 0, 1, or 2, more preferably 0 or 1, and even more preferably 0.

[0054] [ka]

[0055] In equation (A3), n 301 and n 302 Each of these is an independent integer between 0 and 4, and n 301 Individual Ra 301 and n 302 Individual Ra 302each independently represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. n 301 is preferably 0, 1 or 2, more preferably 0 or 1, and still more preferably 0. n 302 is preferably 0, 1 or 2, more preferably 0 or 1, and still more preferably 0.

[0056]

Chemical Formula

[0057] In formula (A4), n 401 is an integer of 0 to 6, and n 401 Ra groups 401 each independently represent an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. n 401 is preferably an integer of 0 to 4, more preferably 0, 1 or 2, and still more preferably 0.

[0058] Ra in formula (A1) 101 , Ra in formula (A2) 201 and Ra 202 , Ra in formula (A3) 301 and Ra 302 and Ra in formula (A4) 401 have the same specific embodiments and preferred embodiments, so hereinafter, Ra 101 , Ra 201 , Ra 202 , Ra 301 , Ra 302 and Ra 401 will be collectively described as "Ra".

[0059] The alkyl group having 1 to 10 carbon atoms for Ra may be linear, branched or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 6, more preferably 1 to 4, and still more preferably 1 or 2. Examples of linear alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups. Examples of branched alkyl groups having 3 to 10 carbon atoms include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, tert-pentyl group, isohexyl group, sec-hexyl group, tert-hexyl group, isoheptyl group, sec-heptyl group, tert-heptyl group, isooctyl group, sec-octyl group, tert-octyl group, isononyl group, sec-nonyl group, tert-nonyl group, isodecyl group, sec-decyl group, tert-decyl group, and the like. Examples of cyclic alkyl groups with 3 to 10 carbon atoms include the cyclopropyl group and the cyclobutyl group. Examples include cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, cyclooctyl groups, cyclononyl groups, cyclodecyl groups, and polycyclic alkyl groups (e.g., bicyclic, tricyclic, spirocyclic) formed by linking these monocyclic alkyl groups.

[0060] The aryl group with 6 to 12 carbon atoms related to Ra may be monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 to 10, and more preferably 6. Examples of aryl groups having 6 to 12 carbon atoms include phenyl, biphenyl, 1-naphthyl, and 2-naphthyl groups.

[0061] The alkyl group in the alkoxy group having 1 to 6 carbon atoms related to Ra may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2. Examples of linear alkoxy groups having 1 to 6 carbon atoms include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, and n-hexyloxy groups. Examples of branched alkoxy groups having 3 to 6 carbon atoms include isopropoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, isopentyloxy group, neopentyloxy group, tert-pentyloxy group, isohexyloxy group, sec-hexyloxy group, and tert-hexyloxy group. Examples of cyclic alkoxy groups having 3 to 6 carbon atoms include cyclopropoxy, cyclobutoxy, cyclopentyloxy, and cyclohexyloxy groups.

[0062] Below are examples of dicarboxylic acid units (A1) (A1-1) to (A1-9). Dicarboxylic acid units (A1) are not limited to these examples.

[0063] [ka]

[0064] Below are examples of dicarboxylic acid units (A2) (A2-1) to (A2-3). Dicarboxylic acid units (A2) are not limited to these examples.

[0065] [ka]

[0066] The following are specific examples of dicarboxylic acid units (A3), namely (A3-1) and (A3-2). However, dicarboxylic acid units (A3) are not limited to these examples.

[0067] [ka]

[0068] Below are examples of dicarboxylic acid units (A4-1) to (A4-3). Dicarboxylic acid units (A4) are not limited to these examples.

[0069] [ka]

[0070] The dicarboxylic acid units (A) are preferably (A1-1), (A1-7), (A2-3), (A3-2), and (A4-3) as shown in the above examples, with (A2-3) being the most preferred.

[0071] Total mass percentage of dicarboxylic acid units (A1) to (A4) in polyester resin (1) Preferably, it is 15% by mass or more and 60% by mass or less. When the total mass percentage of dicarboxylic acid units (A1) to (A4) is 15% by mass or more, the abrasion resistance of the photosensitive layer is good. From this viewpoint, the total mass percentage of dicarboxylic acid units (A1) to (A4) is more preferably 20% by mass or more, and even more preferably 25% by mass or more. When the total mass percentage of dicarboxylic acid units (A1) to (A4) is 60% by mass or less, peeling of the photosensitive layer can be suppressed. From this viewpoint, the total mass percentage of dicarboxylic acid units (A1) to (A4) is more preferably 55% by mass or less, and even more preferably 50% by mass or less. The dicarboxylic acid units (A1) to (A4) contained in the polyester resin (1) may be one type or two or more types.

[0072] Other dicarboxylic acid units (A) besides dicarboxylic acid units (A1) to (A4) include, for example, aliphatic dicarboxylic acid units (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacic acid), alicyclic dicarboxylic acid units (e.g., cyclohexanedicarboxylic acid), lower alkyl ester units of these (e.g., with 1 to 5 carbon atoms), and aromatic dicarboxylic acid units represented by formulas (A5) to (A8) described later. The polyester resin (1) may contain one or more of these dicarboxylic acid units.

[0073] The dicarboxylic acid unit (A) contained in the polyester resin (1) may be one type or two or more types.

[0074] The diol unit (B) is a constituent unit represented by the following formula (B).

[0075] [ka]

[0076] In equation (B), Ar B1 and Ar B2 Each of these is an aromatic ring which may independently have substituents, L B is a single bond, oxygen atom, sulfur atom or -C(Rb 1 )(Rb 2 )- and n B1 Rb is 0, 1, or 2. 1 and Rb 2 Each of these is independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and Rb 1 and Rb 2 These may be bonded together to form a cyclic alkyl group.

[0077] Ar B1 The aromatic ring may be monocyclic or polycyclic. Examples of aromatic rings include benzene rings, naphthalene rings, anthracene rings, and phenanthrene rings, with benzene rings and naphthalene rings being preferred.

[0078] Ar B1 The hydrogen atoms on the aromatic ring may be substituted with alkyl groups, aryl groups, aralkyl groups, alkoxy groups, aryloxy groups, halogen atoms, etc. B1 When the aromatic ring is substituted, preferred substituents are alkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 12 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms.

[0079] Ar B2The aromatic ring may be monocyclic or polycyclic. Examples of aromatic rings include benzene rings, naphthalene rings, anthracene rings, and phenanthrene rings, with benzene rings and naphthalene rings being preferred.

[0080] Ar B2 The hydrogen atoms on the aromatic ring are alkyl groups, aryl groups, aralkyl groups, and alkoxy groups. It may be substituted with a cy group, aryloxy group, halogen atom, etc. B2 When the aromatic ring is substituted, preferred substituents are alkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 12 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms.

[0081] Rb 1 and Rb 2 The alkyl group having 1 to 20 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 18, more preferably 1 to 14, and even more preferably 1 to 10.

[0082] Rb 1 and Rb 2 The aryl group having 6 to 12 carbon atoms may be monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 to 10, and more preferably 6.

[0083] Rb 1 and Rb 2 The alkyl group in the aralkyl group having 7 to 20 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group in the aralkyl group having 7 to 20 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2. Rb 1 and Rb 2 The aryl group in the aralkyl group having 7 to 20 carbon atoms may be monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 to 10, and more preferably 6.

[0084] The diol unit (B) preferably includes at least one selected from the group consisting of the diol unit (B1) represented by the following formula (B1), the diol unit (B2) represented by the following formula (B2), the diol unit (B3) represented by the following formula (B3), the diol unit (B4) represented by the following formula (B4), the diol unit (B5) represented by the following formula (B5), the diol unit (B6) represented by the following formula (B6), the diol unit (B7) represented by the following formula (B7), and the diol unit (B8) represented by the following formula (B8).

[0085] The diol unit (B) more preferably includes at least one selected from the group consisting of the diol unit (B1) represented by the following formula (B1), the diol unit (B2) represented by the following formula (B2), the diol unit (B4) represented by the following formula (B4), the diol unit (B5) represented by the following formula (B5), and the diol unit (B6) represented by the following formula (B6). It is even more preferable to include at least one selected from the group consisting of a diol unit (B1) represented by the following formula (B1), a diol unit (B2) represented by the following formula (B2), a diol unit (B5) represented by the following formula (B5), and a diol unit (B6) represented by the following formula (B6). It is even more preferable to include at least one selected from the group consisting of a diol unit (B1) represented by the following formula (B1), a diol unit (B2) represented by the following formula (B2), and a diol unit (B6) represented by the following formula (B6), It is most preferable that the material contains at least one selected from the group consisting of a diol unit (B1) represented by the following formula (B1) and a diol unit (B2) represented by the following formula (B2).

[0086] [ka]

[0087] In equation (B1), Rb 101 Rb is a branched alkyl group having 4 to 20 carbon atoms. 201Rb is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 401 , Rb 501 , Rb 801 and Rb 901 Each of these is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0088] Rb 101 The number of carbon atoms in the branched alkyl group having 4 to 20 carbon atoms is preferably 4 to 16, more preferably 4 to 12, and even more preferably 4 to 8. 101 Specific examples include isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, tert-pentyl group, isohexyl group, sec-hexyl group, tert-hexyl group, isoheptyl group, sec-heptyl group, tert-heptyl group, isooctyl group, sec-octyl group, tert-octyl group, isononyl group, sec-nonyl group, tert-nonyl group, isodecyl group, sec-decyl group, tert-decyl group, isododecyl group, sec-dodecyl group, tert-dodecyl group, tert-tetradecyl group, tert-pentadecyl group, and the like.

[0089] [ka]

[0090] In equation (B2), Rb 102 Rb is a linear alkyl group having 4 to 20 carbon atoms. 202 Rb is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 402 , Rb 502 , Rb 802 and Rb 902 Each of these is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0091] Rb 102The number of carbon atoms in the linear alkyl group having 4 to 20 carbon atoms is preferably 4 to 16, more preferably 4 to 12, and even more preferably 4 to 8. 102 Specific examples include n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, tridecyl group, n-tetradecyl group, n-pentadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-icosyl group, and the like.

[0092] [ka]

[0093] In equation (B3), Rb 113 and Rb 213 Each of these is independently a hydrogen atom, a linear alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, d is an integer between 7 and 15, and Rb 403 , Rb 503 , Rb 803 and Rb 903 Each of these is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0094] Rb 113 and Rb 213 The number of carbon atoms in the linear alkyl group having 1 to 3 carbon atoms is preferably 1 or 2, and more preferably 1. Specific examples of this group include a methyl group, an ethyl group, and an n-propyl group. Rb 113 and Rb 213The alkyl group in the alkoxy group having 1 to 4 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 4 carbon atoms is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. Specific examples of the group include methoxy, ethoxy, n-propoxy, n-butoxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, cyclopropoxy, and cyclobutoxy groups. Rb 113 and Rb 213 Examples of halogen atoms involved include fluorine, chlorine, bromine, and iodine atoms.

[0095] [ka]

[0096] In equation (B4), Rb 104 and Rb 204 Each is independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Rb 404 , Rb 504 , Rb 804 and Rb 904 Each of these is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0097] Rb 104 The alkyl group having 1 to 3 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 or 2, and more preferably 1. Rb 104 Specific examples include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, and cyclopropyl groups.

[0098] [ka]

[0099] In equation (B5), Ar 105Rb is an aryl group having 6 to 12 carbon atoms or an aralkyl group having 7 to 20 carbon atoms. 205 Rb is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 405 , Rb 505 , Rb 805 and Rb 905 Each of these is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0100] Ar 105 The aryl group having 6 to 12 carbon atoms may be monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 to 10, and more preferably 6. Ar 105 The alkyl group in the aralkyl group having 7 to 20 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group in the aralkyl group having 7 to 20 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2. 105 The aryl group in the aralkyl group having 7 to 20 carbon atoms is monocyclic and It may be either polycyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 to 10, and more preferably 6. Examples of aralkyl groups with 7 to 20 carbon atoms include benzyl group, phenylethyl group, phenylpropyl group, 4-phenylbutyl group, phenylpentyl group, phenylhexyl group, phenylheptyl group, phenyloctyl group, phenylnonyl group, naphthylmethyl group, naphthylethyl group, anthracenylmethyl group, and phenylcyclopentylmethyl group.

[0101] [ka]

[0102] In equation (B6), Rb 116 and Rb 216 Each of these is independently a hydrogen atom, a linear alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, e is an integer between 4 and 6, and Rb 406, Rb 506 , Rb 806 and Rb 906 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0103] Rb 116 and Rb 216 for the linear alkyl group having 1 to 3 carbon atoms, the number of carbon atoms is preferably 1 or 2, more preferably 1. Specific examples of the group include a methyl group, an ethyl group, and an n-propyl group. Rb 116 and Rb 216 the alkyl group in the alkoxy group having 1 to 4 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms of the alkyl group in the alkoxy group having 1 to 4 carbon atoms is preferably 1 to 3, more preferably 1 or 2, and still more preferably 1. Specific examples of the group include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an isopropoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, a cyclopropoxy group, and a cyclobutoxy group. Rb 116 and Rb 216 examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0104]

Chemical Formula

[0105] In formula (B7), Rb 407 , Rb 507 , Rb 807 and Rb 907 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0106]

Chemical Formula

[0107] In equation (B8), Rb 408 , Rb 508 , Rb 808 and Rb 908 Each of these is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0108] Rb of equation (B1) 201 Rb of formula (B2) 202 Rb in formula (B4) 204 and Rb of formula (B5) 205 Since the specific form and preferred form are the same, hereinafter referred to as Rb 201 , Rb 202 , Rb 204 and Rb 205 to "Rb 200 They explain it collectively as "[...]."

[0109] Rb 200 The alkyl group having 1 to 3 carbon atoms may be linear, branched, or cyclic. The alkyl group preferably has 1 or 2 carbon atoms, and more preferably 1 carbon atom. Examples of alkyl groups having 1 to 3 carbon atoms include methyl, ethyl, n-propyl, isopropyl, and cyclopropyl groups.

[0110] Rb of equation (B1) 401 Rb of formula (B2) 402 Rb of formula (B3) 403 Rb in formula (B4) 404 Rb in formula (B5) 405 Rb in formula (B6) 406 Rb in equation (B7) 407 and Rb of formula (B8) 408 Since the specific form and preferred form are the same, hereinafter referred to as Rb 401 , Rb 402 , Rb 403 , Rb 404 , Rb 405 , Rb 406 , Rb 407 and Rb 408 to "Rb 400 They explain it collectively as "[...]."

[0111] Rb 400 The alkyl group having 1 to 4 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. Examples of linear alkyl groups having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, and n-butyl groups. Examples of branched alkyl groups having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl, and tert-butyl groups. Examples of cyclic alkyl groups having 3 or 4 carbon atoms include the cyclopropyl group and the cyclobutyl group.

[0112] Rb 400 The alkyl group in the alkoxy group having 1 to 6 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2. Examples of linear alkoxy groups having 1 to 6 carbon atoms include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, and n-hexyloxy groups. Examples of branched alkoxy groups having 3 to 6 carbon atoms include isopropoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, isopentyloxy group, neopentyloxy group, tert-pentyloxy group, isohexyloxy group, sec-hexyloxy group, and tert-hexyloxy group. Examples of cyclic alkoxy groups having 3 to 6 carbon atoms include cyclopropoxy, cyclobutoxy, cyclopentyloxy, and cyclohexyloxy groups.

[0113] Rb 400 Examples of halogen atoms involved include fluorine, chlorine, bromine, and iodine atoms.

[0114] Rb of equation (B1) 501 Rb of formula (B2) 502 Rb of formula (B3)503 Rb in formula (B4) 504 Rb in formula (B5) 505 Rb in formula (B6) 506 Rb in equation (B7) 507 and Rb of formula (B8) 508 Since the specific form and preferred form are the same, hereinafter referred to as Rb 501 , Rb 502 , Rb 503 , Rb 504 , Rb 505 , Rb 506 , Rb 507 and Rb 508 to "Rb 500 They explain it collectively as "[...]."

[0115] Rb 500 The alkyl group having 1 to 4 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. Examples of linear alkyl groups having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, and n-butyl groups. Examples of branched alkyl groups having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl, and tert-butyl groups. Examples of cyclic alkyl groups having 3 or 4 carbon atoms include the cyclopropyl group and the cyclobutyl group.

[0116] Rb 500 The alkyl group in the alkoxy group having 1 to 6 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2. Examples of linear alkoxy groups having 1 to 6 carbon atoms include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, and n-hexyloxy groups. Examples of branched alkoxy groups having 3 to 6 carbon atoms include isopropoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, isopentyloxy group, neopentyloxy group, tert-pentyloxy group, isohexyloxy group, sec-hexyloxy group, and tert-hexyloxy group. Examples of cyclic alkoxy groups having 3 to 6 carbon atoms include cyclopropoxy, cyclobutoxy, cyclopentyloxy, and cyclohexyloxy groups.

[0117] Rb 500 Examples of halogen atoms involved include fluorine, chlorine, bromine, and iodine atoms.

[0118] Rb of equation (B1) 801 Rb of formula (B2) 802 Rb of formula (B3) 803 Rb in formula (B4) 804 Rb in formula (B5) 805 Rb in formula (B6) 806 Rb in equation (B7) 807 and Rb of formula (B8) 808 Since the specific form and preferred form are the same, hereinafter referred to as Rb 801 , Rb 802 , Rb 803 , Rb 804 , Rb 805 , Rb 806 , Rb 807 and Rb 808 to "Rb 800 They explain it collectively as "[...]."

[0119] Rb 800 The alkyl group having 1 to 4 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. Examples of linear alkyl groups having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, and n-butyl groups. Examples of branched alkyl groups having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl, and tert-butyl groups. Examples of the cyclic alkyl group having 3 or 4 carbon atoms include a cyclopropyl group and a cyclobutyl group.

[0120] Rb 800 The alkyl group in the alkoxy group having 1 to 6 carbon atoms according to may be any of linear, branched or cyclic. The number of carbon atoms of the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and still more preferably 1 or 2. Examples of the linear alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentyloxy group, and an n-hexyloxy group. Examples of the branched alkoxy group having 3 to 6 carbon atoms include an isopropoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, an isopentyloxy group, a neopentyloxy group, a tert-pentyloxy group, an isohexyloxy group, a sec-hexyloxy group, and a tert-hexyloxy group. Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include a cyclopropoxy group, a cyclobutoxy group, a cyclopentyloxy group, and a cyclohexyloxy group.

[0121] Rb 800 Examples of the halogen atom according to include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0122] Rb in formula (B1) 901 , Rb in formula (B2) 902 , Rb in formula (B3) 903 , Rb in formula (B4) 904 , Rb in formula (B5) 905 , Rb in formula (B6) 906 , Rb in formula (B7) 907 and Rb in formula (B8) 908 have the same specific embodiments and preferred embodiments, so hereinafter, Rb 901 , Rb 902 , Rb 903 , Rb 904 , Rb 905 , Rb 906 , Rb907 and Rb 908 to "Rb 900 They explain it collectively as "[...]."

[0123] Rb 900 The alkyl group having 1 to 4 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. Examples of linear alkyl groups having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, and n-butyl groups. Examples of branched alkyl groups having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl, and tert-butyl groups. Examples of cyclic alkyl groups having 3 or 4 carbon atoms include the cyclopropyl group and the cyclobutyl group.

[0124] Rb 900 The alkyl group in the alkoxy group having 1 to 6 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2. Examples of linear alkoxy groups having 1 to 6 carbon atoms include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, and n-hexyloxy groups. Examples of branched alkoxy groups having 3 to 6 carbon atoms include isopropoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, isopentyloxy group, neopentyloxy group, tert-pentyloxy group, isohexyloxy group, sec-hexyloxy group, and tert-hexyloxy group. Examples of cyclic alkoxy groups having 3 to 6 carbon atoms include cyclopropoxy, cyclobutoxy, cyclopentyloxy, and cyclohexyloxy groups.

[0125] Rb 900 Examples of halogen atoms involved include fluorine, chlorine, bromine, and iodine atoms.

[0126] The following are specific examples of diol units (B1), specifically (B1-1) to (B1-6). Diol units (B1) are not limited to these examples.

[0127] [ka]

[0128] The following are specific examples of diol units (B2), specifically (B2-1) to (B2-11). Diol units (B2) are not limited to these examples.

[0129] [ka]

[0130] The following are specific examples of diol units (B3), namely (B3-1) to (B3-4). Diol units (B3) are not limited to these examples.

[0131] [ka]

[0132] The following are examples of diol units (B4-1) to (B4-7). Diol units (B4) are not limited to these examples.

[0133] [ka]

[0134] The following are examples of diol units (B5-1) to (B5-6). Diol units (B5) are not limited to these examples.

[0135] [ka]

[0136] The following are examples of diol units (B6-1) to (B6-4). Diol units (B6) are not limited to these examples.

[0137] [ka]

[0138] The following are examples of diol units (B7-1) to (B7-3). Diol units (B7) are not limited to these examples.

[0139] [ka]

[0140] The following are specific examples of diol units (B8), namely (B8-1) to (B8-3). Diol units (B8) are not limited to these examples.

[0141] [ka]

[0142] The diol unit (B) contained in the polyester resin may be one type or two or more types.

[0143] The mass percentage of diol units (B) in the polyester resin is preferably 25% by mass or more and 80% by mass or less. When the mass percentage of diol units (B) is 25% by mass or more, peeling of the photosensitive layer can be suppressed. From this viewpoint, the mass percentage of diol units (B) is more preferably 30% by mass or more, and even more preferably 35% by mass or more. When the mass percentage of diol units (B) is 80% by mass or less, it is possible to maintain solubility in the coating solution for forming the photosensitive layer and improve abrasion resistance. From this viewpoint, the mass percentage of diol units (B) is more preferably 75% by mass or less, and even more preferably 70% by mass or less.

[0144] Other diol units besides diol unit (B) include, for example, aliphatic diol units (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol) and alicyclic diol units (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A). The polyester resin (1) may contain one or more of these diol units.

[0145] In particular, the polyester resin (1) is preferably a polyester resin having a dicarboxylic acid unit represented by (A2) and a diol unit represented by (B1) below, and more preferably a polyester resin having a dicarboxylic acid unit represented by (A2-3) and a diol unit represented by (B1-4). By applying these polyester resins, improved cleanability and reduced wear of the electrophotographic photoreceptor are achieved in both image formation processes, whether repeatedly forming low-image-density images in high-temperature, high-humidity environments or repeatedly forming high-image-density images in low-temperature, low-humidity environments.

[0146] The ends of the polyester resin (1) may be sealed or modified with an end-capping agent or molecular weight modifier used during manufacturing. Examples of end-capping agents or molecular weight modifiers include monohydric phenols, monohydric acid chlorides, monohydric alcohols, and monohydric carboxylic acids. Examples of monohydric phenols include phenol, o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-propylphenol, m-propylphenol, p-propylphenol, o-tert-butylphenol, m-tert-butylphenol, p-tert-butylphenol, pentylphenol, hexylphenol, octylphenol, nonylphenol, 2,6-dimethylphenol derivatives, 2-methylphenol derivatives, and o-phenyl Phenol, m-phenylphenol, p-phenylphenol, o-methoxyphenol, m-methoxyphenol, p-methoxyphenol, 2,3,5-trimethylphenol, 2,3,6-trimethylphenol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, 2-phenyl-2-(4-hydroxyphenyl)propane, 2-phenyl-2-(2-hydroxyphenyl)propane, 2-phenyl-2-(3-hydroxyphenyl Propane is one example. Examples of monovalent acid chlorides include monofunctional acid halides such as benzoyl chloride, benzoic acid chloride, methanesulfonyl chloride, phenyl chloroformate, acetate chloride, butyrate chloride, octic acid chloride, benzoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, benzenephosphonyl chloride, and their substituted derivatives. Examples of monohydric alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, pentanol, hexanol, dodecyl alcohol, stearyl alcohol, benzyl alcohol, and phenethyl alcohol. Examples of monocarboxylic acids include acetic acid, propionic acid, octanoic acid, cyclohexanecarboxylic acid, benzoic acid, toluic acid, phenylacetic acid, p-tert-butylbenzoic acid, and p-methoxyphenylacetic acid.

[0147] The weight-average molecular weight of the polyester resin (1) is preferably 30,000 to 300,000, more preferably 40,000 to 250,000, and even more preferably 50,000 to 200,000. The molecular weight of the polyester resin (1) is the polystyrene-equivalent molecular weight measured by GPC (gel permeation chromatography). Tetrahydrofuran is used as the eluent for GPC.

[0148] Methods for producing polyester resin (1) include interfacial polymerization, solution polymerization, and melt polymerization.

[0149] Details of the charge transport layer containing polyester resin (1) and the single-layer photosensitive layer containing polyester resin (1) will be described later.

[0150] The following describes the components of the photoreceptor 12 (12A, 12B). Note that symbols will be omitted in this explanation.

[0151] [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, and belts 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 volume resistivity of 1 × 10⁻⁶. 13 This refers to a value less than Ω·cm.

[0152] When the 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 in order to suppress interference fringes that occur when irradiated with laser light. When non-interfering light is used as the light source, roughening to prevent interference fringes is not particularly necessary, but it is suitable for a longer lifespan because it suppresses the occurrence of defects due to irregularities on the surface of the conductive substrate.

[0153] Methods for roughening a surface include, for example, wet honing, which involves suspending an abrasive in water and spraying it onto a conductive substrate; centerless grinding, which involves pressing a conductive substrate against a rotating grinding wheel and continuously grinding it; and anodizing.

[0154] One method for roughening the surface is to disperse conductive or semiconductive powder in a resin without roughening the surface of the conductive substrate, to form a layer on the surface of the conductive substrate, and then roughen the surface with the particles dispersed in that layer.

[0155] Anodizing roughening treatment involves forming an oxide film on the surface of a conductive substrate (e.g., aluminum) by anodizing it in an electrolyte solution. Examples of electrolyte solutions include sulfuric acid solution and oxalic acid solution. However, the porous anodic oxide film formed by anodizing is chemically active, easily contaminated, and exhibits large resistance fluctuations depending on the environment. Therefore, it is preferable to perform a sealing treatment on the porous anodic oxide film, which involves sealing the micropores of the oxide film by volume expansion due to a hydration reaction using pressurized steam or boiling water (metal salts such as nickel may be added), thereby converting it into a more stable hydrated oxide.

[0156] The thickness of the anodic oxide film is preferably, for example, 0.3 μm to 15 μm. When the film thickness is within this range, it tends to exhibit barrier properties against injection and tends to suppress the increase in residual potential due to repeated use.

[0157] The conductive substrate may be treated with an acidic treatment solution or with boehmite. Treatment with an acidic solution is carried out, for example, as follows: First, an acidic solution containing phosphoric acid, chromic acid, and hydrofluoric acid is prepared. The mixing ratio of phosphoric acid, chromic acid, and hydrofluoric acid in the acidic solution is, for example, in the range of 10% to 11% by mass for phosphoric acid, 3% to 5% by mass for chromic acid, and 0.5% to 2% by mass for hydrofluoric acid, and the total concentration of these acids is preferably in the range of 13.5% to 18% by mass. The treatment temperature is preferably, for example, 42°C to 48°C. The film thickness is preferably 0.3 μm to 15 μm.

[0158] The boehmite treatment is carried out, for example, by immersing the material in pure water at 90°C to 100°C for 5 to 60 minutes, or by contacting it with heated steam at 90°C to 120°C for 5 to 60 minutes. The film thickness is preferably 0.1 μm to 5 μm. This can be further treated with anodic oxidation using an electrolyte solution with low film solubility, such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, or citrate.

[0159] [Sublayer] The undercoat layer is, for example, a layer containing inorganic particles and a binder resin.

[0160] As for inorganic particles, for example, powder resistance (volume resistivity) 1 × 10 2 Ω cm or more 1×10 11 Examples include inorganic particles with a size of Ω·cm or less. Among these, suitable inorganic particles having the above-mentioned resistance values ​​include 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.

[0161] The specific surface area of ​​inorganic particles using the BET method is, for example, 10 m². 2 A value of 1g or more is preferable. The volume-average particle size of the inorganic particles is preferably between 50 nm and 2000 nm (preferably between 60 nm and 1000 nm).

[0162] The inorganic particle content is preferably 10% by mass or more and 80% by mass or less relative to the binder resin, and more preferably 40% by mass or more and 80% by mass or less.

[0163] The inorganic particles may be surface-treated. Two or more types of inorganic particles with different surface treatments or particle sizes may be mixed and used.

[0164] Examples of surface treatment agents include silane coupling agents, titanate-based coupling agents, aluminum-based coupling agents, and surfactants. Silane coupling agents are particularly preferred, and silane coupling agents having an amino group are more preferred.

[0165] Examples of silane coupling agents having an amino group include, but are not limited to, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane.

[0166] Silane coupling agents may be used in combination of two or more types. For example, a silane coupling agent having an amino group may be used in combination with another silane coupling agent. Examples of other silane coupling agents include, but are not limited to, vinyltrimethoxysilane, 3-methacrylateoxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and 3-chloropropyltrimethoxysilane.

[0167] The surface treatment method using the surface treatment agent may be any known method, and may be either a dry or wet method.

[0168] The amount of surface treatment agent applied is preferably, for example, 0.5% by mass or more and 10% by mass or less relative to the inorganic particles.

[0169] In this case, it is preferable for the underlayer to contain electron-accepting compounds (acceptor compounds) along with inorganic particles, from the viewpoint of improving the long-term stability of electrical properties and carrier blocking ability.

[0170] Examples of electron-accepting compounds include electron-transporting substances such as compounds having anthraquinone structures; quinone compounds such as chloranil and bromanil; 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; diphenoquinone compounds such as 3,3',5,5'-tetra-t-butyldiphenoquinone; and benzophenone compounds. In particular, compounds having an anthraquinone structure are preferred as electron-accepting compounds. Examples of compounds having an anthraquinone structure include hydroxyanthraquinone compounds, aminoanthraquinone compounds, and aminohydroxyanthraquinone compounds. Specifically, examples of preferred compounds include anthraquinone, alizarin, quinizalin, anthralphine, purpurin, and their derivatives.

[0171] The electron-accepting compound may be dispersed in the underlayer together with inorganic particles, or it may be present attached to the surface of the inorganic particles.

[0172] Methods for attaching electron-accepting compounds to the surface of inorganic particles include, for example, dry methods or wet methods.

[0173] The dry method involves, for example, adding an electron-accepting compound, either directly or dissolved in an organic solvent, dropwise while stirring inorganic particles with a mixer that has a high shear force, or spraying it with dry air or nitrogen gas, to adhere the electron-accepting compound to the surface of the inorganic particles. When adding or spraying the electron-accepting compound, it is preferable to do so at a temperature below the boiling point of the solvent. After adding or spraying the electron-accepting compound, further baking at 100°C or higher may be performed. The baking temperature and time are not particularly limited as long as electrophotographic characteristics can be obtained.

[0174] The wet method involves dispersing inorganic particles in a solvent using, for example, a stirrer, ultrasonic disperser, sand mill, attritor, or ball mill, while adding an electron-accepting compound. After stirring or dispersion, the solvent is removed, and the electron-accepting compound adheres to the surface of the inorganic particles. Solvent removal methods include, for example, filtration or distillation. After solvent removal, further baking at 100°C or higher may be performed. The baking temperature and time are not particularly limited as long as electrophotographic characteristics can be obtained. In the wet method, the water content of the inorganic particles may be removed before adding the electron-accepting compound. Examples of this include removing water while stirring and heating in the solvent, or removing water by azeotrope with the solvent.

[0175] The electron-accepting compound may be applied before or after surface treatment with a surface treatment agent to the inorganic particles, or it may be applied simultaneously with the surface treatment with the surface treatment agent.

[0176] The content of the electron-accepting compound is preferably, for example, 0.01% by mass or more and 20% by mass or less relative to the inorganic particles, and more preferably 0.01% by mass or more and 10% by mass or less.

[0177] Examples of known polymer compounds used as the binder resin for the undercoat include acetal resin (e.g., polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, unsaturated polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, urea resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin, alkyd resin, epoxy resin, 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 include charge-transporting resins having charge-transporting groups, conductive resins (e.g., polyaniline), and the like.

[0178] Among these, a resin insoluble in the coating solvent of the upper layer is preferred as the binder resin used for the undercoat layer. In particular, a resin obtained by the reaction of a curing agent with at least one resin selected from the group consisting of thermosetting resins such as urea resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin, unsaturated polyester resin, alkyd resin, and epoxy resin is preferred. When using two or more of these binder resins in combination, the mixing ratio is set as needed.

[0179] The undercoat may contain various additives to improve electrical properties, environmental stability, and image quality. Examples of known additives include electron-transporting pigments such as polycyclic condensation and azo pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, and silane coupling agents. As mentioned above, silane coupling agents are used for surface treatment of inorganic particles, but they may also be added to the undercoat as additives.

[0180] Examples of silane coupling agents used as additives include vinyltrimethoxysilane, 3-methacrylateoxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and 3-chloropropyltrimethoxysilane.

[0181] Examples of zirconium chelate compounds include zirconium butoxide, ethyl zirconium acetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetate zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, and isostearate zirconium butoxide.

[0182] Examples of titanium chelate compounds include tetraisopropyl titanate, tetran-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, titanium triethanolamine, and polyhydroxytitanium stearate.

[0183] Examples of aluminum chelating compounds include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethylacetoacetate aluminum diisopropylate, and aluminum tris(ethylacetoacetate).

[0184] These additives may be used individually or as a mixture or polycondensate of multiple compounds.

[0185] The underlayer should ideally have a Vickers hardness of 35 or higher. The surface roughness (ten-point average roughness) of the undercoat layer should be adjusted to between 1 / (4n) (where n is the refractive index of the upper layer) and 1 / 2 of the exposure laser wavelength λ used, in order to suppress moiré patterns. Resin particles may be added to the undercoat to adjust the surface roughness. Examples of resin particles include silicone resin particles and cross-linked polymethyl methacrylate resin particles. The surface of the undercoat may also be polished to adjust the surface roughness. Polishing methods include buffing, sandblasting, wet honing, and grinding.

[0186] The formation of the undercoat is not particularly limited, and known formation methods can be used. For example, it can be carried out by forming a coating film of an undercoat-forming solution obtained by adding the above components to a solvent, drying the coating film, and heating it if necessary.

[0187] Solvents for preparing the coating solution for forming the undercoat include known organic solvents such as alcohol-based solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone-based solvents, ketone alcohol-based solvents, ether-based solvents, and ester-based solvents. Specific examples of these solvents include common organic solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene.

[0188] Known methods for dispersing inorganic particles when preparing a coating solution for forming an undercoat include, for example, roll mills, ball mills, vibrating ball mills, attritors, sand mills, colloid mills, and paint shakers.

[0189] Conventional methods for applying the undercoating solution onto a conductive substrate include, for example, the blade coating method, wire bar coating method, spray coating method, immersion coating method, bead coating method, air knife coating method, and curtain coating method.

[0190] The thickness of the undercoat layer is preferably set to a range of 15 μm or more, and more preferably 20 μm to 50 μm.

[0191] [Middle class] 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 resins used in the intermediate layer include polymer compounds such as acetal resin (e.g., polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, and melamine resin. The intermediate layer may contain an organometallic compound. Examples of organometallic compounds used in the intermediate layer include those containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon. The compounds used in these intermediate layers may be used individually, as a mixture of multiple compounds, or as polycondensates.

[0192] Among these, the intermediate layer is preferably a layer containing an organometallic compound that contains zirconium atoms or silicon atoms.

[0193] The formation of the intermediate layer is not particularly limited, and known formation methods can be used. For example, it can be carried out by forming a coating film of an intermediate layer-forming coating solution obtained by adding the above components to a solvent, drying the coating film, and heating it if necessary. Conventional methods such as immersion coating, push-up coating, wire bar coating, spray coating, blade coating, air knife coating, and curtain coating are used to form the intermediate layer.

[0194] The thickness of the intermediate layer is preferably set to a range of 0.1 μm to 3 μm, for example. The intermediate layer may also be used as a base layer.

[0195] [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 when using non-coherent light sources such as LEDs (Light Emitting Diodes) or organic EL (Electroluminescence) image arrays.

[0196] Examples of charge-generating materials include azo pigments such as bisazo and trisazo; fused aromatic pigments such as dibromoanthonthrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; and trigonal selenium.

[0197] Among these, in order to accommodate laser exposure in the near-infrared region, it is preferable to use a metallic phthalocyanine pigment or a metal-free phthalocyanine pigment as the charge generating material. Specifically, for example, hydroxygallium phthalocyanine, chlorogallium phthalocyanine, dichlorotin phthalocyanine, titanyl phthalocyanine, etc. are more preferable.

[0198] On the other hand, to accommodate laser exposure in the near-ultraviolet region, preferred charge-generating materials include fused aromatic pigments such as dibromoanthonthrone, thioindigo-based pigments, porphyrazine compounds, zinc oxide, trigonal selenium, and bisazo pigments.

[0199] The above charge generating material may also be used when using non-coherent light sources such as LEDs and organic EL image arrays, which have a central emission wavelength between 450 nm and 780 nm.

[0200] When n-type semiconductors such as fused aromatic pigments, perylene pigments, and azo pigments are used as charge-generating materials, dark currents are less likely to be generated, and image defects called black spots can be suppressed even in thin films. The n-type is determined using the commonly used time-of-flight method, which is determined by the polarity of the photocurrent that flows, and materials that readily carry electrons as carriers rather than holes are classified as n-type.

[0201] The binder resin used in the charge generation layer can be selected from a wide range of insulating resins, or it may 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 (such as polycondensates of bisphenols and aromatic divalent carboxylic acids), 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, and polyvinylpyrrolidone resin. Here, "insulating properties" refer to a volume resistivity of 1 × 10⁻⁶. 13 This refers to a value of Ω·cm or greater. These binder resins can be used individually or in combination of two or more types.

[0202] The mixing ratio of the charge-generating material to the binder resin is preferably within the range of 10:1 to 1:10 by mass ratio.

[0203] The charge generation layer may also contain other known additives.

[0204] The formation of the charge generation layer is not particularly limited, and known formation methods can be used. For example, it can be carried out by forming a coating film of a coating solution for forming a charge generation layer by adding the above components to a solvent, drying the coating film, and heating it as necessary. The charge generation layer may also be formed by vapor deposition of a charge generation material. Formation of the charge generation layer by vapor deposition is particularly suitable when using fused ring aromatic pigments or perylene pigments as the charge generation material.

[0205] Solvents for preparing the coating solution for forming the charge generation layer include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene. These solvents may be used individually or in mixtures of two or more.

[0206] Methods for dispersing particles (e.g., charge-generating materials) in a coating solution for forming a charge-generating layer include, for example, media dispersers such as ball mills, vibrating ball mills, attritors, sand mills, and horizontal sand mills, as well as media-less dispersers such as stirrers, ultrasonic dispersers, roll mills, and high-pressure homogenizers. Examples of high-pressure homogenizers include collision methods, which disperse the dispersion by causing liquid-liquid collisions or liquid-wall collisions under high pressure, and penetration methods, which disperse the dispersion by penetrating fine channels under high pressure. During this dispersion, it is effective to set the average particle size of the charge-generating material in the coating solution for forming the charge-generating layer to 0.5 μm or less, preferably 0.3 μm or less, and more preferably 0.15 μm or less.

[0207] Conventional methods for applying the charge generation layer forming coating solution onto the undercoat (or intermediate layer) include, for example, the blade coating method, wire bar coating method, spray coating method, immersion coating method, bead coating method, air knife coating method, and curtain coating method.

[0208] The thickness of the charge generation layer is preferably set to a range of 0.1 μm to 5.0 μm, more preferably 0.2 μm to 2.0 μm.

[0209] [Charge transport layer] The charge transport layer is, for example, a layer containing a charge transport material and a binder resin. The charge transport layer contains the above-mentioned polyester resin (1) as a binder resin. The charge transport layer may also contain binder resins other than the polyester resin (1) described above. However, the proportion of the polyester resin (1) in the total binder resin of the charge transport layer is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and still more preferably 100% by mass or more.

[0210] Examples of charge transport materials include 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, which are electron transport compounds. Other examples of charge transport materials 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 individually or in combination of two or more, but are not limited to these.

[0211] As charge transport materials, from the viewpoint of charge mobility, the triarylamine derivative shown in the following structural formula (a-1) and the benzidine derivative shown in the following structural formula (a-2) are preferred.

[0212] [ka]

[0213] In structural formula (a-1), Ar T1 Ar T2 , and Ar T3 Each is independently a substituted or unsubstituted aryl group, -C6H4-C(R T4 )=C(R T5 )(R T6 ), or -C6H4-CH=CH-CH=C(R T7 )(R T8 ) indicates R T4 , R T5 , R T6 , R T7 , and RT8 Each of these independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Substituents for each of the above groups include halogen atoms, alkyl groups having 1 to 5 carbon atoms, and alkoxy groups having 1 to 5 carbon atoms. Furthermore, substituted amino groups substituted with alkyl groups having 1 to 3 carbon atoms are also examples of substituents for each of the above groups.

[0214] [ka]

[0215] In structural formula (a-2), R T91 and R T92 Each of these independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. T101 , R T102 , R T111 and R T112 Each of these independently consists of a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, a substituted or unsubstituted aryl group, and -C(R T12 )=C(R T13 )(R T14 ), or -CH=CH-CH=C(R T15 )(R T16 ) shows R T12 , R T13 , R T14 , R T15 and R T16 Each of these independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Tm1, Tm2, ​​Tn1, and Tn2 each independently represent an integer between 0 and 2. Substituents for each of the above groups include halogen atoms, alkyl groups having 1 to 5 carbon atoms, and alkoxy groups having 1 to 5 carbon atoms. Furthermore, substituted amino groups substituted with alkyl groups having 1 to 3 carbon atoms are also examples of substituents for each of the above groups.

[0216] Among the triarylamine derivatives represented by structural formula (a-1) and the benzidine derivatives represented by structural formula (a-2), in particular, "-C6H4-CH=CH-CH=C(R T7 )(R T8 Triarylamine derivatives having ")" and "-CH=CH-CH=C(R T15 )(R T16 A benzidine derivative having ) is preferred from the viewpoint of charge mobility.

[0217] Other binder resins used in the charge transport layer include polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole, and polysilane. Among these, polycarbonate resin or polyarylate resin is preferred as the binder resin. These binder resins can be used individually or in combination of two or more. The preferred mixing ratio of the charge transport material to the binder resin is between 10:1 and 1:5 by mass.

[0218] The charge transport layer may also contain other known additives.

[0219] Known formation methods can be applied to form the charge transport layer. For example, a coating film of a charge transport layer forming solution is formed by adding a material to a solvent, the coating film is dried, and the charge transport layer is formed by heating as needed.

[0220] Examples of solvents for preparing coating solutions for charge transport layer formation include organic solvents such as aromatic hydrocarbons like benzene, toluene, xylene, and chlorobenzene; ketones like acetone and 2-butanone; halogenated aliphatic hydrocarbons like methylene chloride, chloroform, and ethylene chloride; and cyclic or linear ethers like tetrahydrofuran and ethyl ether. These solvents may be used individually or in mixtures of two or more.

[0221] When applying a coating solution for forming a charge transport layer onto a charge generation layer, possible coating methods include blade coating, wire bar coating, spray coating, immersion coating, bead coating, air knife coating, and curtain coating.

[0222] The thickness of the charge transport layer is set, for example, preferably within the range of 5 μm to 50 μm, and more preferably within the range of 10 μm to 30 μm.

[0223] [Single-layer photosensitive layer] A single-layer photosensitive layer is, for example, a layer comprising a charge generating material, a charge transporting material, a binder resin, and other additives as needed. These materials are the same as those described for the charge generating layer and the charge transporting layer. However, the single-layer photosensitive layer contains the above-mentioned polyester resin (1) as a binder resin.

[0224] The charge-generating material content in the single-layer photosensitive layer is preferably 0.1% to 10% by mass, and more preferably 0.8% to 5% by mass, relative to the total solid content. The charge transport material content in the single-layer photosensitive layer should be between 5% and 50% by mass relative to the total solid content.

[0225] The method for forming a single-layer photosensitive layer is the same as the method for forming a charge generation layer or a charge transport layer.

[0226] The thickness of the single-layer photosensitive layer is, for example, 5 μm to 50 μm, and preferably 10 μm to 40 μm.

[0227] <Charging device> The charging device 15 charges the surface of the photoreceptor 12. The charging device 15 includes, for example, a charging member 14 that is provided in contact with or without contact with the surface of the photoreceptor 12 to charge the surface of the photoreceptor 12, and a power supply 28 (an example of a voltage application unit for the charging member) that applies a charging voltage to the charging member 14. The power supply 28 is electrically connected to the charging member 14.

[0228] Examples of charging components 14 in the charging device 15 include contact-type chargers using conductive charging rolls, charging brushes, charging films, charging rubber blades, charging tubes, etc. Other examples of charging components 14 include non-contact type roller chargers, scorotron chargers or corotron chargers utilizing corona discharge, and other known chargers.

[0229] <Electrostatic image forming device> The electrostatic image forming apparatus 16 forms an electrostatic image on the surface of a charged photoreceptor 12. Specifically, for example, the electrostatic image forming apparatus 16 irradiates the surface of the photoreceptor 12, which has been charged by a charging member 14, with light L modulated based on the image information of the image to be formed, thereby forming an electrostatic image on the photoreceptor 12 that corresponds to the image information.

[0230] Examples of electrostatic image forming apparatus 16 include optical equipment having a light source that exposes an image-like object with light such as semiconductor laser light, LED light, or liquid crystal shutter light.

[0231] <Developing equipment> The developing device 18 is located, for example, downstream of the photoreceptor 12 in the rotational direction from the irradiation position of light L by the electrostatic image forming device 16. The developing device 18 has a storage section for containing the developer. This storage section contains a developer having toner, which includes toner particles and an external additive. The toner is stored, for example, in a charged state within the developing device 18.

[0232] The developing apparatus 18 includes a developing member 18A that develops an electrostatic image formed on the surface of the photoreceptor 12 using a developer containing, for example, toner particles and an external additive, and a power supply 32 that applies a developing voltage to the developing member 18A. The developing member 18A is electrically connected to the power supply 32, for example.

[0233] The developing element 18A of the developing device 18 is selected according to the type of developer, but an example is a developing roll having a developing sleeve with a magnet built in.

[0234] The developing apparatus 18 (including the power supply 32) is, for example, a control device provided in the image forming apparatus 10. The device 36 is electrically connected to the developing element 18A and is driven and controlled by the control device 36 to apply a developing voltage to the developing element 18A. The developing element 18A, to which the developing voltage has been applied, is charged to a developing potential corresponding to the developing voltage. The developing element 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 contained in the developer from the developing device 18 to the surface of the photoreceptor 12. On the surface of the photoreceptor 12 to which the toner has been supplied, the formed electrostatic charge image is developed as a toner image.

[0235] <Transfer device> The transfer device 31 is provided, for example, downstream of the developing member 18A in the rotational direction of the photoreceptor 12. The transfer device 31 includes, for example, a transfer member 20 that transfers the toner image formed on the surface of the photoreceptor 12 to the recording medium 30A, and a power supply 30 that applies a transfer voltage to the transfer member 20. The transfer member 20 is, for example, cylindrical and transports the recording medium 30A between itself and the photoreceptor 12. The transfer member 20 is electrically connected to, for example, the power supply 30.

[0236] Examples of the transfer member 20 include contact-type transfer chargers using belts, rollers, films, rubber cleaning blades, etc., and non-contact type transfer chargers that are known themselves, such as scorotron transfer chargers or corotron transfer chargers that utilize corona discharge.

[0237] The transfer device 31 (including the power supply 30) is electrically connected to, for example, a control device 36 provided in the image forming apparatus 10, and is driven and controlled by the control device 36 to apply a transfer voltage to the transfer member 20. The transfer member 20, to which the transfer voltage has been applied, is charged to a transfer potential corresponding to the transfer voltage.

[0238] When a transfer voltage with the opposite polarity to the toner that constitutes the toner image formed on the photoreceptor 12 is applied to the transfer member 20 from the power supply 30 of the transfer member 20, for example, a transfer electric field with an electric field strength that moves each toner constituting the toner image on the photoreceptor 12 from the photoreceptor 12 to the transfer member 20 side by electrostatic force is formed in the region where the photoreceptor 12 and the transfer member 20 face each other (see transfer region 32A in Figure 1).

[0239] The recording medium 30A is housed in, for example, a housing (not shown), and is transported from this housing along a transport path 34 by a plurality of transport members (not shown) to the transfer region 32A, which is the region where the photoreceptor 12 and the transfer member 20 face each other. In the example shown in Figure 1, it is transported in the direction of arrow B. Once the recording medium 30A reaches the transfer region 32A, the toner image on the photoreceptor 12 is transferred to the recording medium 30A by a transfer electric field formed in the region, for example, when a transfer voltage is applied to the transfer member 20. That is, for example, the toner image is transferred onto the recording medium 30A by the movement of toner from the surface of the photoreceptor 12 to the recording medium 30A. The toner image on the photoreceptor 12 is then transferred onto the recording medium 30A by the transfer electric field.

[0240] <Cleaning device> The cleaning device 22 has a cleaning blade 22A that contacts the surface of the photoreceptor 12 and cleans the surface of the photoreceptor 12.

[0241] The cleaning device 22 is located downstream of the transfer area 32A in the rotational direction of the photoreceptor 12. After the toner image has been transferred to the recording medium 30A, the cleaning device 22 cleans any residual toner particles adhering to the photoreceptor 12. In addition to residual toner particles, the cleaning device 22 also cleans any other adhering substances such as paper dust.

[0242] The cleaning device 22 has a cleaning blade 22A, and the tip of the cleaning blade 22A is brought into contact with the photoreceptor 12 in a direction opposite to the rotation direction of the photoreceptor 12 to clean the surface of the photoreceptor 12. This device removes surface deposits (including residual toner particles).

[0243] (Cleaning blade) The cleaning blade 22A will be described below. However, the reference numerals will be omitted in this explanation. The cleaning blade may have a single layer, a double layer, three or more layers, or any other configuration. Examples of single-layer cleaning blades include cleaning blades in which the entire contact member, including the contact portion with the photoreceptor, is made of a single material. Examples of a two-layer cleaning blade include a first layer consisting of a contact member made entirely of a single material, including the part that contacts the photoreceptor, and a second layer, which is formed on the back side of the first layer and made of a different material from the contact member. Examples of cleaning blades with three or more layers include cleaning blades that have another layer between the first and second layers in the two-layer cleaning blade described above. The cleaning blade is used, for example, by being bonded to a rigid plate-shaped support material.

[0244] (Contact member) The contact member is a member that includes a contact portion that comes into contact with the photoreceptor. The contact member is made of, for example, a rubber elastic material. Examples of rubber elastic materials include polyurethane rubber, polyimide rubber, silicone rubber, fluororubber, propylene rubber, and butadiene rubber. However, from the viewpoint of having excellent wear resistance and mechanical strength, the contact member is preferably made of a rubber elastic material including urethane rubber.

[0245] -Polyurethane rubber- Polyurethane rubber is a polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component. The polyurethane rubber may also be a polyurethane rubber obtained by polymerizing a resin having functional groups that can react with the isocyanate groups of the polyisocyanate, in addition to the polyol component, as needed.

[0246] It is preferable that the polyurethane rubber has hard segments and soft segments. "Hard segments" and "soft segments" refer to segments in the polyurethane rubber material in which the material constituting the former is relatively harder than the material constituting the latter, and the material constituting the latter is relatively softer than the material constituting the former. The materials that make up the hard segment (hard segment material) include low molecular weight polyol components among polyol components, and resins having functional groups that can react with the isocyanate groups of polyisocyanates. On the other hand, the materials that make up the soft segment (soft segment material) include high molecular weight polyol components among polyol components.

[0247] Here, the average particle size of the hard segment aggregates is preferably 1 μm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less. By making the average particle size of the hard segment aggregates 1 μm or larger, the frictional resistance of the contact member surface is more easily reduced. As a result, blade behavior is stabilized, and localized wear is more easily suppressed. On the other hand, by making the average particle size of the hard segment aggregates 10 μm or less, the occurrence of chipping becomes easier to suppress.

[0248] The average particle size of hard segment aggregates is measured as follows: Using a polarizing microscope (Olympus BX51-P), images are captured at 20x magnification, and the images are binarized through image processing. Five points are measured for each cleaning blade (measuring the particle size of five aggregates per point), and the particle size (equivalent to a circle diameter) of the aggregates is measured for all 20 cleaning blades. The average particle size is then calculated from a total of 500 particles. For image binarization, the image processing software OLYMPUS Stream essentials (manufactured by Olympus Corporation) is used, and the hue / saturation / luminance thresholds are adjusted so that the crystalline and hard segment aggregates appear black, and the amorphous parts (corresponding to soft segments) appear white.

[0249] • Polyol components The polyol component includes both high molecular weight polyols and low molecular weight polyols.

[0250] The polymeric polyol component is a polyol with a number-average molecular weight of 500 or more (preferably 500 to 5000). Examples of polymeric polyol components include well-known polyols such as polyester polyols obtained by dehydration condensation of low molecular weight polyols and dibasic acids, polycarbonate polyols obtained by reaction of low molecular weight polyols and alkyl carbonates, polycaprolactone polyols, and polyether polyols. Examples of commercially available polymeric polyols include Praxel 205 and Praxel 240 manufactured by Daicel Corporation.

[0251] Here, the number-average molecular weight is the value measured by gel permeation chromatography (GPC). The same applies hereafter.

[0252] These polymeric polyols may be used individually or in combination of two or more types.

[0253] The polymerization ratio of the high-molecular-weight polyol component is preferably 30 mol% to 50 mol% relative to the total polymerization components of the polyurethane rubber, and more preferably 40 mol% to 50 mol%.

[0254] Low molecular weight polyol components are polyols with a molecular weight (number average molecular weight) of less than 500. Low molecular weight polyols are materials that function as chain length extenders and crosslinking agents.

[0255] Examples of low molecular weight polyol components include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,20-eicosanediol. Among these, 1,4-butanediol is preferably used as the low molecular weight polyol component.

[0256] Examples of low molecular weight polyol components include diols (bifunctional), triols (trifunctional), or tetraols (tetrafunctional), which are well known as chain length extenders and crosslinking agents. These polyols may be used individually or in combination of two or more types.

[0257] The polymerization ratio of the low molecular weight polyol component is preferably more than 50 mol% and 75 mol% or less relative to the total polymerization component of the polyurethane rubber, more preferably 52 mol% to 75 mol%, more preferably 55 mol% to 75 mol%, and even more preferably 55 mol% to 60 mol%.

[0258] It is preferable that 1,4-butanediol is included as a low molecular weight polyol component in an amount greater than 50 mol% and less than or equal to 75 mol% (preferably 52 mol% to 75 mol%, more preferably 55 mol% to 75 mol%, and even more preferably 55 mol% to 60 mol%) relative to the total polyol components (high molecular weight polyol + low molecular weight polyol). By increasing the proportion of 1,4-butanediol to over 50 mol%, localized wear is more easily suppressed. On the other hand, by keeping the proportion of 1,4-butanediol below 75 mol%, chipping is more easily suppressed. Furthermore, the proportion of 1,4-butanediol to the total low molecular weight polyol component is 80 mol% or more, preferably 90 mol% or more, and more preferably 100 mol%. In other words, it is most preferable to use 1,4-butanediol as the total low molecular weight polyol component.

[0259] • Polyisocyanate components Examples of polyisocyanate components include 4,4'-diphenylmethane diisocyanate (MDI), 2,6-toluene diisocyanate (TDI), 1,6-hexane diisocyanate (HDI), 1,5-naphthalene diisocyanate (NDI), and 3,3'-dimethylbiphenyl-4,4'-diisocyanate (TODI).

[0260] As polyisocyanate components, 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), and hexamethylene diisocyanate (HDI) are more preferable.

[0261] These polyisocyanate components may be used individually or in combination of two or more.

[0262] The polymerization ratio of the polyisocyanate component is preferably 5 mol% to 25 mol%, and more preferably 10 mol% to 20 mol%, relative to the total polymerization components of the polyurethane rubber.

[0263] • Resins having functional groups that can react with isocyanate groups Resins having functional groups that can react with isocyanate groups (hereinafter referred to as "functional group-containing resins") are preferably flexible resins, and more preferably aliphatic resins having a linear structure from the viewpoint of flexibility. Specific examples of functional group-containing resins include acrylic resins containing two or more hydroxyl groups, polybutadiene resins containing two or more hydroxyl groups, and epoxy resins containing two or more epoxy groups.

[0264] Examples of commercially available acrylic resins containing two or more hydroxyl groups include Actflow (grades: UMB-2005B, UMB-2005P, UMB-2005, UME-2005, etc.) manufactured by Soken Chemical Co., Ltd.

[0265] Examples of commercially available polybutadiene resins containing two or more hydroxyl groups include R-45HT, manufactured by Idemitsu Kosan Co., Ltd.

[0266] The epoxy resin having two or more epoxy groups is preferably one that is more flexible and tough than conventional epoxy resins, rather than having the hard and brittle properties of conventional epoxy resins. For example, in terms of molecular structure, the epoxy resin preferably has a structure (flexible skeleton) in its main chain that allows for high main chain mobility. Examples of flexible skeletons include alkylene skeletons, cycloalkane skeletons, and polyoxyalkylene skeletons, with polyoxyalkylene skeletons being particularly preferred. Furthermore, in terms of physical properties, epoxy resins with a lower viscosity relative to their molecular weight are preferred compared to conventional epoxy resins. Specifically, those with a weight-average molecular weight in the range of 900 ± 100 and 25 The viscosity at °C is preferably within the range of 15,000 ± 5,000 mPa·s, and more preferably within the range of 15,000 ± 3,000 mPa·s. Examples of commercially available epoxy resins having this property include DIC's EPICLON EXA-4850-150.

[0267] The polymerization ratio of the functional group-containing resin should be within a range that does not impair the desirable physical properties of the cleaning blade.

[0268] • Method for manufacturing polyurethane rubber, and method for molding contact members Polyurethane rubber is manufactured using common polyurethane manufacturing methods such as the prepolymer method and the one-shot method. The prepolymer method is suitable for this embodiment because it yields polyurethane with excellent abrasion resistance and chipping properties, but the manufacturing method is not limiting. The contact members (or single-layer cleaning blades) are manufactured by forming a cleaning blade composition containing a polyurethane rubber prepolymer, etc., into a sheet using, for example, centrifugal molding or extrusion molding, and then cutting or otherwise processing it as needed.

[0269] Examples of catalysts used in the production of polyurethane rubber include amine compounds such as tertiary amines, quaternary ammonium salts, and organometallic compounds such as organotin compounds. Examples of the above-mentioned tertiary amines include trialkylamines such as triethylamine, tetraalkyldiamines such as N,N,N',N'-tetramethyl-1,3-butanediamine, amino alcohols such as dimethylethanolamine, ethoxylated amines, ethoxylated diamines, esteramines such as bis(diethylethanolamine)adipate, cyclohexylamine derivatives such as triethylenediamine (TEDA) and N,N-dimethylcyclohexylamine, morpholine derivatives such as N-methylmorpholine and N-(2-hydroxypropyl)-dimethylmorpholine, and piperazine derivatives such as N,N'-diethyl-2-methylpiperazine and N,N'-bis-(2-hydroxypropyl)-2-methylpiperazine.

[0270] Examples of quaternary ammonium salts include 2-hydroxypropyltrimethylammonium octylate, 1,5-diazabicyclo[4.3.0]nonene-5(DBN)octylate, 1,8-diazabicyclo[5.4.0]undecene-7(DBU)octylate, DBU oleate, DBU-p-toluenesulfonate, DBU formate, and 2-hydroxypropyltrimethylammonium formate.

[0271] Examples of organotin compounds include dialkyltin compounds such as dibutyltin dilaurate and dibutyltin di(2-ethylhexoate), as well as stannous 2-ethylcaproate and stannous oleate.

[0272] Among these catalysts, triethylenediamine (TEDA), a tertiary ammonium salt, is preferred in terms of hydrolysis resistance, while quaternary ammonium salts are preferred in terms of processability. Among quaternary ammonium salts, 1,5-diazabicyclo[4.3.0]nonene-5(DBN)·octylate, 1,8-diazabicyclo[5.4.0]undecene-7(DBU)-octylate, and DBU-formate are preferred due to their high reaction activity.

[0273] The catalyst content is preferably in the range of 0.0005% by mass or more and 0.03% by mass or less of the total polyurethane rubber constituting the contact member, and particularly preferably 0.001% by mass or more and 0.01% by mass or less. These can be used individually or in combination of two or more types.

[0274] (impregnated hardened layer) The cleaning blade has an impregnated and cured layer on the contact portion (i.e., the blade tip) that comes into contact with the surface of the photoreceptor, which is made of a composition comprising an isocyanate compound and at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers. The impregnation and hardening layer is formed in the area from the surface of the blade tip to a depth of 100 μm.

[0275] The impregnation treatment layer is a layer obtained by impregnating the tip of the blade with a surface treatment solution containing the above components and an organic solvent as the above composition, and then curing the above components of the surface treatment solution. The impregnation layer is formed integrally with the surface layer of the blade tip so that it gradually becomes less dense from the surface towards the interior.

[0276] -Isocyanate compounds- Examples of isocyanate compounds include 2,6-tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), paraphenylenedi diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI), and 3,3'-dimethyldiphenyl-4,4'-diisocyanate (TODI), as well as their polymers and modified forms. Examples of modified isocyanate compounds include urethane prepolymers in which isocyanate compounds are prepolymerized together with polyols.

[0277] -Fluorine-based polymers- A fluorinated polymer is a polymer containing fluorine atoms. Preferably, the fluorinated polymer is one that chemically bonds with an isocyanate compound through a reaction. Specifically, examples of fluorine-based polymers include block copolymers of alkyl (meth)acrylate and alkyl fluoride (meth)acrylate, or derivatives thereof. From the viewpoint of solubility in organic solvents, fluorinated polymers are preferably polymers having hydroxyl groups, alkyl groups, or carboxyl groups.

[0278] -Silicone-based polymer- A silicone polymer is a polymer containing silicon atoms, and preferably a polymer containing siloxane bonds. Furthermore, it is preferable that the silicone polymer is a polymer that chemically bonds with an isocyanate compound through reaction. Specifically, examples of silicone-based polymers include block copolymers of alkyl (meth)acrylates and siloxane (meth)acrylates (such as (meth)acrylic resins having polydimethylsiloxane as a side chain), and their derivatives. From the viewpoint of solubility in organic solvents, silicone polymers having hydroxyl groups, alkyl groups, or carboxyl groups are preferred.

[0279] Furthermore, one method for confirming the presence of an impregnated hardened layer on the blade tip (its surface) is to perform structural estimation or compositional analysis of the surface material of the blade tip using analytical techniques such as Fourier transform infrared spectrophotometer (FTIR) or X-ray photoelectron spectroscopy (XPS).

[0280] The total amount of fluorine-based polymers and silicone-based polymers in the surface treatment solution is preferably 8 to 13 parts by mass, more preferably 9 to 13 parts by mass, and even more preferably 10 to 13 parts by mass, per 100 parts by mass of isocyanate compound.

[0281] The organic solvent is preferably one that dissolves fluorine-based polymers and silicone-based polymers and is compatible with isocyanate compounds. Specifically, examples include ethyl acetate, methyl ethyl ketone (MEK), toluene, acetone, and cyclohexanone. Alternatively, reactive diluents such as 2-hydroxyethyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, and trimethylolpropane triacrylate may be used as the organic solvent.

[0282] The impregnation-cured layer is preferably an impregnation-cured layer of an isocyanate compound and a silicone-based polymer. Applying this impregnation-cured layer further improves cleanability and reduces wear on the electrophotographic photoreceptor, whether the image is repeatedly formed in a high-temperature, high-humidity environment with low image density, or repeatedly formed in a low-temperature, low-humidity environment with high image density.

[0283] For example, the impregnation and hardening layer is formed by impregnating at least the tip of the blade with an impregnation treatment solution, removing the organic solvent by drying, and then forming the hardened layer by heat treatment. The impregnation treatment is not particularly limited, and conventional coating methods such as blade coating, wire bar coating, spray coating, immersion coating, bead coating, air knife coating, and curtain coating can be applied. If the impregnation treatment is by immersion coating, the immersion time can be in the range of 10 seconds to 60 seconds, for example. Examples of drying conditions after impregnation include a temperature of 20°C to 30°C and a time of 1 minute to 10 minutes. Examples of heat treatment conditions include a temperature of 50°C to 80°C and a time of 60 minutes to 90 minutes.

[0284] (F content and Si content at the blade tip) -Surface layer proportions of F and Si- In the cleaning blade, the ratio of the total amount of F and Si present within 200 nm from the surface of the contact portion that contacts the electrophotographic photoreceptor to the total amount A present within 5 μm from the surface of the contact portion that contacts the electrophotographic photoreceptor is preferably 75% or more, more preferably 85% to 95%, and even more preferably 90% to 93%.

[0285] When the ratio of the total amount B of F and Si to the total amount A of F and Si is 75% or more, the blade tip is moderately reduced in friction, suppressing blade curling and wear, even when repeatedly forming low-image-density images in a high-temperature, high-humidity environment. As a result, improved cleanability and reduced wear of the electrophotographic photoreceptor are achieved in both image formation, whether repeatedly forming low-image-density images in a high-temperature, high-humidity environment or repeatedly forming high-image-density images in a low-temperature, low-humidity environment. On the other hand, from the viewpoint of suppressing a decrease in cleaning performance due to a decrease in surface pressure of the blade tip on the photoreceptor caused by insufficient retraction of the blade tip, it is preferable that the ratio of the total amount B of F and Si to the total amount A of F and Si is 95% or less.

[0286] Here, in both image formation, whether low-image-density images are repeatedly formed in a warm, high-humidity environment or high-image-density images are repeatedly formed in a low-temperature, low-humidity environment, the total amount A of F and Si is preferably 300 atm%·nm or more and 410 atm%·nm or less, and more preferably 350 atm%·nm or more and 370 atm%·nm or less, from the viewpoint of improving cleanability and reducing wear of the electrophotographic photoreceptor.

[0287] -Total amount of surface F and Si- The total amount of F and Si C present on the surface of the contact portion of the cleaning blade that comes into contact with the electrophotographic photoreceptor is preferably 15 atm% or more, more preferably 18 atm% to 25 atm%, and even more preferably 20 atm% to 22 atm%. When the total amount of F and Si (C) is 15 atm% or more, the blade tip is moderately reduced in friction, suppressing blade curling and wear. As a result, improved cleanability and reduced wear of the electrophotographic photoreceptor are achieved in both image formation, whether repeatedly forming low-image-density images in a high-temperature, high-humidity environment or repeatedly forming high-image-density images in a low-temperature, low-humidity environment. On the other hand, from the viewpoint of suppressing a decrease in cleaning performance due to a decrease in surface pressure of the blade tip on the photoreceptor caused by insufficient retraction of the blade tip, the total amount C of F and Si is preferably 25 atm% or less.

[0288] -Total amount of F and Si at 50nm position- In the cleaning blade, the total amount D of F and Si present at a position 50 nm from the surface of the contact portion that contacts the electrophotographic photoreceptor is preferably 0.3 atm% or more, more preferably 0.5 atm% to 7.0 atm%, and even more preferably 1.0 atm% to 2.0 atm%. When the total amount D of F and Si is 0.3 atm% or more, the friction of the blade tip is moderately reduced over time, suppressing blade curling and wear. As a result, improved cleanability and reduced wear of the electrophotographic photoreceptor are achieved over time in both image formation processes, whether repeatedly forming low-image-density images in a high-temperature, high-humidity environment or repeatedly forming high-image-density images in a low-temperature, low-humidity environment. On the other hand, from the viewpoint of suppressing the decrease in cleaning performance due to a decrease in surface pressure of the blade tip on the photoreceptor caused by insufficient retraction of the blade tip over time, the total amount D of F and Si is preferably 7.0 atm% or less.

[0289] -Method for measuring F and Si content at the blade tip- The method for measuring the total amounts of F and Si A to D in the contact area of ​​the cleaning blade that comes into contact with the electrophotographic photoreceptor is as follows. In other words, the method for analyzing the amount of F and Si elements from the surface to the depth direction of the blade tip is as follows.

[0290] A sample is obtained by cutting out a region that includes the surface of the blade tip (i.e., the surface of the contact area on the blade that comes into contact with the photoreceptor). X-ray photoelectron spectroscopy (XPS) is performed on the sample under the following conditions, etching from the surface corresponding to the blade tip in the depth direction. The elements to be analyzed are N, C, O, F, and Si. Then, profiles of the F and Si content in the depth direction are obtained. Furthermore, the surface ratio of F and Si in the cleaning blade (the ratio of the total amount B of F and Si to the total amount A of F and Si) can be determined by plotting the depth from the contact area of ​​the cleaning blade and the elemental ratio obtained from the depth direction analysis described above, with SA representing the area up to a depth of 5 μm and SB representing the area up to a depth of 200 nm, and calculating the ratio using the formula "SB / SA × 100". -XPS Requirements- ·XPS device: JPS-9030 (JEOL XPS) • X-ray type: MgKα • Acceleration voltage: 10kV • Emission current: 10mA • Measurement step: 0.1eV • Passage energy: 10 eV Dwell Time: 100~500ms Etching gas: Argon Ion gun acceleration voltage: 500V • Etching rate: 30 nm / min (SiO2 equivalent)

[0291] In the depth profile of F and Si content, the total amount of F and Si within 5 μm from the blade tip surface is defined as the total amount of F and Si A. In the depth profile of F and Si content, the total amount of F and Si within 200 nm from the blade tip surface is determined as the total amount of F and Si B. In the depth profile of F and Si content, the total amount of F and Si at a position of 0 nm from the blade tip surface is determined as the total amount of F and Si C. In the depth profile of F and Si content, the total amount of F and Si at a position 50 nm from the blade tip surface is determined as the total amount of F and Si D.

[0292] The total amounts of F and Si A to D are the component composition of the impregnated hardened layer and the formation of the impregnated hardened layer. This is adjusted by the processing time (e.g., immersion time) of the impregnation solution.

[0293] (100% modulus of the blade tip) The 100% modulus (hereinafter referred to as "M100") at 23°C of the surface of the contact portion of the cleaning blade that comes into contact with the electrophotographic photoreceptor is preferably 5 MPa to 23 MPa, preferably 10 MPa to 20 MPa, and more preferably 13 MPa to 18 MPa. In the following, the 100% modulus at 23°C at the contact point of the cleaning blade will also be referred to as "M100".

[0294] If the M100 at the blade tip is less than 13 MPa, the rigidity of the blade tip is ensured, and blade curling and wear are suppressed. When the M100 at the blade tip is 23 MPa or less, excessive rigidity at the blade tip is suppressed, ensuring sufficient blade tip retraction and thus ensuring cleaning efficiency. As a result, in both image formation processes—whether repeatedly forming low-image-density images in a high-temperature, high-humidity environment or repeatedly forming high-image-density images in a low-temperature, low-humidity environment—improved cleanability and reduced wear on the electrophotographic photoreceptor are achieved.

[0295] The M100 at the tip of the blade is measured by the following method. A dumbbell-shaped test specimen (Type 3) is taken from the tip of the blade being measured. At 23°C, measurements were taken using a dumbbell-shaped No. 3 test specimen in accordance with JIS K6251 (2010), at a tensile speed of 500 mm / min, and the value was determined from the stress at 100% strain. The measuring device used was, for example, a Strograph AE Elastomer manufactured by Toyo Seiki Co., Ltd.

[0296] Methods for setting M100 at the blade tip within the above range include adjusting the composition of the blade tip. Specifically, when the contact member including the blade tip (i.e., the contact portion) contains polyurethane rubber, methods include adjusting the content of the polyisocyanate component; when a crosslinking agent is used in the manufacture of the contact member, methods include adjusting at least one of the type and amount of the crosslinking agent; and combinations thereof. Note that increasing the content of the polyisocyanate component increases M100.

[0297] <Static eliminator> The static elimination device 24 is, for example, located downstream of the cleaning device 22 in the rotational direction of the photoreceptor 12. After the toner image has been transferred, the static elimination device 24 exposes the surface of the photoreceptor 12 to remove static electricity. Specifically, for example, the static elimination device 24 is electrically connected to a control device 36 provided in the image forming apparatus 10, and is driven and controlled by the control device 36 to expose the entire surface of the photoreceptor 12 (specifically, for example, the entire image forming area) to remove static electricity.

[0298] Examples of static elimination devices 24 include devices having a light source such as a tungsten lamp that emits white light or a light-emitting diode (LED) that emits red light.

[0299] <Fusing device> The fixing device 26 is, for example, located downstream of the transfer area 32A in the transport direction of the transport path 34 of the recording medium 30A. The fixing device 26 includes a fixing member 26A and a pressurizing member 26B positioned in contact with the fixing member 26A, and fixes the toner image transferred onto the recording medium 30A at the contact point between the fixing member 26A and the pressurizing member 26B. Specifically, for example, the fixing device 26 is electrically connected to a control device 36 provided in the image forming apparatus 10, and is driven and controlled by the control device 36 to fix the toner image transferred onto the recording medium 30A to the recording medium 30A by heat and pressure.

[0300] Examples of the fixing device 26 include known fixing devices such as hot roller fixing devices and oven fixing devices. Specifically, for example, the fixing device 26 may be a well-known fixing device comprising a fixing roll or fixing belt as a fixing member 26A and a pressure roll or pressure belt as a pressure member 26B.

[0301] Here, the recording medium 30A, which has been transported along the transport path 34 and has the toner image transferred to it by passing through the area where the photoreceptor 12 and the transfer member 20 face each other (transfer area 32A), is further transported along the transport path 34 by a transport member (not shown) to the installation position of the fixing device 26, where the toner image on the recording medium 30A is fixed.

[0302] The recording medium 30A, on which the image has been formed by fixing the toner image, is discharged to the outside of the image forming apparatus 10 by a plurality of transport members (not shown in the figure). The photoreceptor 12 is then discharged by the static elimination device 24 and then recharged to a charging potential by the charging device 15.

[0303] <Operation of the image forming apparatus> An example of the operation of the image forming apparatus 10 according to this embodiment will be described. Note that various operations of the image forming apparatus 10 are performed by a control program executed in the control device 36.

[0304] The image forming operation of the image forming apparatus 10 will be described. First, the surface of the photoreceptor 12 is charged by the charging device 15. The electrostatic image forming device 16 exposes the charged surface of the photoreceptor 12 based on image information. This forms an electrostatic image on the photoreceptor 12 corresponding to the image information. In the developing device 18, the electrostatic image formed on the surface of the photoreceptor 12 is developed with a developer containing toner. This forms a toner image on the surface of the photoreceptor 12. In the transfer device 31, the toner image formed on the surface of the photoreceptor 12 is transferred to the recording medium 30A. The toner image transferred to the recording medium 30A is fixed by the fuser device 26. Meanwhile, the surface of the photoreceptor 12 after the toner image has been transferred is cleaned by the cleaning blade 22A in the cleaning device 22, and then static electricity is removed by the static elimination device 24.

[0305] The configuration of the image forming apparatus described in this embodiment is merely an example, and it goes without saying that its configuration may be modified without departing from the spirit of this embodiment. [Examples]

[0306] The embodiments of the invention will be described in detail below with reference to examples, but the embodiments of the invention are not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" are based on mass.

[0307] In the following descriptions, synthesis, processing, and manufacturing were carried out at room temperature (25°C ± 3°C) unless otherwise specified.

[0308] <Manufacturing of photoreceptors> [Manufacturing of a photoreceptor (1) equipped with a stacked photosensitive layer] (Formation of the lower layer (1)) As a conductive substrate, prepare an aluminum cylindrical tube with an outer diameter of 30 mm, a length of 250 mm, and a wall thickness of 1 mm. Zinc oxide (average particle size 70 nm, specific surface area 15 m²) 2 100 parts of (Teika Co., Ltd.) were mixed with 500 parts of toluene and stirred. 1.3 parts of a silane coupling agent (product name: KBM-603, Shin-Etsu Chemical Co., Ltd., N-2-(aminoethyl)-3-aminopropyltrimethoxysilane) were added and the mixture was stirred for 2 hours. The toluene was then removed by distillation under reduced pressure, and the mixture was baked at 120°C for 3 hours to obtain zinc oxide surface-treated with the silane coupling agent. 110 parts of surface-treated zinc oxide were mixed with 500 parts of tetrahydrofuran by stirring. A solution of 0.6 parts of alizarin dissolved in 50 parts of tetrahydrofuran was added, and the mixture was stirred at 50°C for 5 hours. The solids were then filtered off by vacuum filtration, and the mixture was dried under reduced pressure at 60°C to obtain alizarin-treated zinc oxide. 100 parts of a solution prepared by dissolving 60 parts alizarin-modified zinc oxide, 13.5 parts curing agent (blocked isocyanate, trade name: Sumijule 3175, manufactured by Sumika Covestro Urethane Co., Ltd.), and 15 parts butyral resin (trade name: Esrec BM-1, manufactured by Sekisui Chemical Co., Ltd.) in 68 parts methyl ethyl ketone, and 5 parts methyl ethyl ketone were mixed and dispersed for 2 hours using a sand mill with 1 mmφ glass beads to obtain a dispersion. To the dispersion, 0.005 parts dioctyl tin dilaurate as a catalyst and 4 parts silicone resin particles (trade name: Tospar 145, manufactured by Momentive Performance Materials, Inc.) were added to form a coating liquid for forming the undercoat. To obtain the following, the coating solution for forming the undercoat is applied to the outer surface of the conductive substrate by immersion coating, and drying and curing is performed at 170°C for 40 minutes to form an undercoat (1) with an average thickness of 24 μm.

[0309] (Formation of charge generation layer (1)) A mixture consisting of 15 parts of hydroxygallium phthalocyanine (having diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3° in its X-ray diffraction spectrum using Cukα characteristic X-rays), 10 parts of vinyl chloride / vinyl acetate copolymer resin (product name: VMCH, manufactured by Nippon Unicar Co., Ltd.) as a binder resin, and 200 parts of n-butyl acetate was dispersed for 4 hours using glass beads with a diameter of 1 mm in a sand mill. 175 parts of n-butyl acetate and 180 parts of methyl ethyl ketone were added to the dispersion and stirred to obtain a coating solution for forming the charge generation layer. The coating solution for forming the charge generation layer was immersed and coated onto the undercoat (1), and dried at room temperature (25℃±3℃) to form a charge generation layer (1) with an average thickness of 0.18 μm.

[0310] (Formation of charge transport layer (1)) As a binder resin, 60 parts of a polyester resin having dicarboxylic acid units A2-3 (50 mol) and diol units B1-4 (50 mol), and 40 parts of CTM-1 as a charge transport material were dissolved in 270 parts of tetrahydrofuran and 30 parts of toluene to obtain a coating solution for forming a charge transport layer. The coating solution for forming a charge transport layer was applied by immersion onto a charge generating layer and dried at 145°C for 30 minutes to form a charge transport layer (1) with an average thickness of 24 μm. [ka]

[0311] Through the above process, a photoreceptor (1) is obtained.

[0312] [Manufacturing of photoreceptors (2) to (7) equipped with a stacked photosensitive layer] Photoreceptors (2) to (7) are obtained in the same manner as photoreceptor (1), except that a polyester resin having dicarbon wire units and diol units as shown in Table 1 is used as the binder resin in the formation of the charge transport layer.

[0313] [Manufacturing of a photoreceptor (C1) with a stacked photosensitive layer] In forming the charge transport layer, a polycarbonate resin (PC-1: weight-average molecular weight 45,000) is used as the binder resin, except that a polyester resin is used instead, and a photoreceptor (C1) is obtained in the same manner as photoreceptor (1). [ka]

[0314] <Manufacturing of cleaning blades> [Manufacturing of cleaning blade (1)] (Preparation of blade substrate) 100 parts of polycaprolactone polyol (molecular weight 2000) and 51 parts of 4,4'-diphenylmethane diisocyanate (MDI, DIC Corporation) were reacted at 115°C for 20 minutes. Then, 6.1 parts of 1,4-butanediol and 2.6 parts of trimethylolpropane were mixed in. The mixture was placed in a mold maintained at 140°C and heated and cured for 40 minutes to obtain urethane rubber (1). A urethane rubber (1) is cut to a length of 330 mm, a width of 13.5 mm, and a thickness of 1.9 mm to obtain a urethane rubber sheet (1). Two urethane rubber sheets (1) are bonded together with adhesive to obtain a blade base material.

[0315] (Preparation of impregnation treatment solution (1)) 25 parts of 4,4'-diphenylmethane diisocyanate (MDI, Tosoh Corporation "Millionate MT"), 3 parts of silicone-modified acrylic polymer (8BS-9000, Taisei Fine Chemical Co., Ltd.) as a polymer component, and 80 parts of ethyl acetate are mixed in a ball mill for 4 hours to obtain impregnation treatment solution (1).

[0316] (Formation of impregnated hardened layer (1)) The impregnation treatment solution (1) is adjusted to a liquid temperature of 23°C, and while maintaining the liquid temperature at 23°C, the blade substrate is immersed in the impregnation treatment solution for 90 seconds. Then, it is dried at room temperature for 1 minute, the surface of the blade substrate is wiped with a sponge containing a small amount of toluene, then it is dried at room temperature for 1 minute, and placed in a constant temperature bath at 25°C for 50 minutes to form the impregnation hardened layer (1).

[0317] Through the above steps, a cleaning blade (1) is obtained.

[0318] [Manufacturing of cleaning blades (2) to (14), (C1)] In preparing the impregnation treatment solution (1), cleaning blades (2) to (14) and (C1) are obtained except by changing the amount of 4,4'-diphenylmethane diisocyanate (MDI), the components of the impregnation treatment solution (type and amount of polymer components), and the conditions for forming the impregnated hardened layer (i.e., the immersion time as the impregnation treatment condition) according to Table 1. However, in Table 1, the notation "Si-based polymer" refers to silicone-modified acrylic polymer (8BS-9000; manufactured by Taisei Fine Chemical Co., Ltd.) as the polymer component, and the notation "F-based polymer" refers to the use of fluorosilicone-modified acrylic polymer (8FS-009; manufactured by Taisei Fine Chemical Co., Ltd.).

[0319] The following characteristics of the resulting cleaning blade are shown in Table 1, measured according to the method described above. The ratio of the total amount of F and Si present within 200 nm of the surface of the contact area that contacts the photoreceptor to the total amount of F and Si present within 5 μm of the surface of the contact area that contacts the photoreceptor (referred to as "surface ratio of F + Si"). • The total amount of F and Si present within 5 μm of the surface of the contact area that comes into contact with the photoreceptor (expressed as "Total amount of F + Si within 5 μm") • The total amount of F and Si present within 200 nm of the surface of the contact area that comes into contact with the photoreceptor (expressed as "Total amount of F + Si within 200 nm"). • The total amount of F and Si present on the surface of the contact area that comes into contact with the electrophotographic photoreceptor (expressed as "total amount of F + Si on the surface"). • The total amount of F and Si present at a position 50 nm from the surface of the contact area that comes into contact with the photoreceptor (expressed as "total amount of F + Si at 50 nm").

[0320] <Examples 1-7, 9-11, Comparative Example 3> The photoconductor and cleaning blade shown in Table 1 were installed in the "ApeosPort C-7770" manufactured by Fujifilm Business Innovation Co., Ltd. The photoconductor and cleaning blade were manufactured using the method described above. The resulting image forming apparatus was then used as the image forming apparatus for Examples 1-7, 9-11, and Comparative Example 3.

[0321] <Examples 8, 12-20, Comparative Examples 1-2> The photoreceptor and cleaning blade shown in Table 1 will be installed in the "ApeosPort C-7770" manufactured by Fujifilm Business Innovation Co., Ltd. The resulting image forming apparatus will be used as the image forming apparatus for Examples 8, 12-18 and Comparative Examples 1-2.

[0322] <Rating 1> The following evaluations were performed on the image forming apparatus for Examples 1-7, 9-11, and Comparative Example 3.

[0323] Using the image forming apparatus in each example, 40,000 images with an image density of 0.5% were printed on A4 plain paper in a high-temperature, high-humidity environment of 28°C and 80% relative humidity. Using each example of the image forming apparatus, 40,000 images with an image density of 10% were printed on A4 plain paper in a low-temperature, low-humidity environment of 10°C and 15% relative humidity. The following evaluations were then performed on image formation under each condition.

[0324] [Wear and tear of the photoreceptor] The amount of wear on the photoreceptor after image formation under the above conditions was calculated by measuring the thickness of the photosensitive layer before and after image formation using an eddy current film thickness meter, and evaluating the difference according to the following criteria. The evaluation result is A being the best and E being the worst. -Evaluation Criteria- A: Photoreceptor wear amount ≤ 0.6 μm B: 0.6 μm < Photoreceptor wear amount ≤ 0.8 μm C: 0.8 μm < Photoreceptor wear amount ≤ 1.0 μm D:1.0μm<Photoconductor wear amount≦1.2μm E: 1.2 μm < Photoreceptor wear amount

[0325] [Blade flipped] The entire blade width area during image formation under the above conditions was visually observed and judged according to the following criteria. The evaluation results are categorized as follows: A is the best, and C is the worst. Furthermore, the closer the evaluation result is to A, the more effectively the cleaning blade is prevented from curling. -Evaluation Criteria- A: No blade peeling was observed even with 40,000 blades. B: Blade peeling was observed in 30,000 to 40,000 blades. Blade peeling was observed before 30,000 blades were produced.

[0326] [Blade strain amount] In each example of the image forming apparatus, a strain gauge (KFG-02, manufactured by Kyowa Dengyo Co., Ltd.) was attached with adhesive 1 mm from the tip of the side of the cleaning blade that contracts when in contact with the photoreceptor. The lead wires of the strain gauge were connected to a strain data acquisition unit (NR-ST04, manufactured by Keyence Co., Ltd.), which was then connected to a computer via a data logger (NR-500, manufactured by Keyence Co., Ltd.). The attached strain gauge was used to detect the amount of strain on the cleaning blade as an electrical signal. Then, during image formation under the above conditions, the amount of strain on the cleaning blade was recorded. The maximum and minimum values ​​of the recorded strain were introduced into the following formula to calculate the difference in strain, △. Formula: Difference in strain △ = (Maximum strain) - (Minimum strain) The difference in strain amount obtained (△) was judged according to the following criteria. The evaluation result is A, where A is the best, and E, where E is the worst. The closer the evaluation result is to A, the more stable the behavior of the blade tip during image formation is, and the better the cleaning quality tends to be. -Evaluation Criteria- A: Difference in strain amount △(μST) < 20 B: 20 ​​≤ Difference in strain △(μST) < 30 C: 30 ≤ Difference in strain amount △(μST) < 40 D: 40 ≤ Difference in strain △(μST) < 50 E: 50 ≤ Difference in strain amount △(μST)

[0327] [Sneaking out of the external additive's control] The surface of the photoreceptor after image formation under the above conditions was observed using a Keyence VK-9500 laser microscope to observe the external additive filming (the phenomenon in which the external additive itself, as well as crushed and finely ground external additives, adhere to the surface of the photoreceptor), and the penetration of the toner external additive was evaluated according to the following criteria. -Evaluation Criteria- A: No instances of external additives slipping through have occurred. B: A slight amount of external additives seeped through. This is at a level that is perfectly acceptable in practical use. C: External additives leaked through. This is at an acceptable level for practical use. D: External additives leaked through. This is an unacceptable level for practical use. E: Frequent leakage of external additives. This is an unacceptable level for practical use.

[0328] <Rating 2> The image forming apparatus for Examples 8, 12-20, and Comparative Examples 1-2 will be evaluated in the same manner as in Evaluation 1 above.

[0329] [Table 1]

[0330] From the above results, it can be seen that the image forming apparatus of the example exhibits better cleaning performance and reduces wear on the electrophotographic photoreceptor, compared to the image forming apparatus of the comparative example, in both cases of repeated image formation: when low image density images are repeatedly formed in a high-temperature, high-humidity environment, and when high image density images are repeatedly formed in a low-temperature, low-humidity environment.

[0331] This embodiment includes the following aspects. (((1))) An electrophotographic photoreceptor having a photosensitive layer that constitutes its surface, A charging device for charging the surface of the electrophotographic photoreceptor, A static charge image forming apparatus for forming a static charge image on the surface of the charged electrophotographic photoreceptor, A developing apparatus that contains a developer and develops the electrostatic charge image formed on the surface of the electrophotographic photoreceptor by the developer as a toner image, A transfer device for transferring the toner image formed on the surface of the electrophotographic photoreceptor to the surface of a recording medium, A cleaning device having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans at least residual toner particles from the surface of the electrophotographic photoreceptor, Equipped with, The photosensitive layer in the electrophotographic photoreceptor comprises a polyester resin (1) having a dicarboxylic acid unit (A) represented by the following formula (A) and a diol unit (B) represented by the following formula (B). An image forming apparatus having an impregnated and cured layer of a composition comprising an isocyanate compound and at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers, on the contact portion of the cleaning blade that comes into contact with the electrophotographic photoreceptor. [ka] In equation (A), Ar A1 and Ar A2 Each of these is an aromatic ring which may independently have substituents, L A is a single bond or a divalent linking group, n A1 It is 0, 1, or 2. In equation (B), Ar B1 and Ar B2 Each of these is an aromatic ring which may independently have substituents, L B is a single bond, oxygen atom, sulfur atom or -C(Rb 1 )(Rb 2 )- and n B1 Rb is 0, 1, or 2. 1 and Rb 2 Each of these is independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and Rb 1 and Rb2 These may be bonded together to form a cyclic alkyl group. (((2))) The image forming apparatus according to (((1))), wherein the ratio of the total amount B of F and Si present within 200 nm from the surface of the contact portion in contact with the electrophotographic photoreceptor to the total amount A of F and Si present within 5 μm from the surface of the contact portion in contact with the electrophotographic photoreceptor is 75% or more. (((3))) The image forming apparatus according to (((2))), wherein the ratio of the total amount B of F and Si to the total amount A of F and Si is 85% or more and 95% or less. (((4))) The image forming apparatus according to (((2))) or (((3))), wherein the total amount C of F and Si present on the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is 15 atm% or more. (((5))) The image forming apparatus according to any one of (((2))) to (((4))), wherein the total amount D of F and Si present at a position 50 nm from the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is 0.3 atm% or more. (((6))) The image forming apparatus according to any one of (((1))) to (((5))), wherein the 100% modulus at 23°C of the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is 5 MPa or more and 23 MPa or less. (((7))) The image forming apparatus according to any one of (((1))) to (((6))), wherein the photosensitive layer of the electrophotographic photoreceptor comprises a polyester resin (1) having a dicarboxylic acid unit represented by (A2) below and a diol unit represented by (B1) below. [ka] In equation (A2), n 201 and n 202Each of these is an independent integer between 0 and 4, and n 201 Individual Ra 201 and n 202 Individual Ra 202 Each of these is independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. In equation (B1), Rb 101 Rb is a branched alkyl group having 4 to 20 carbon atoms. 201 Rb is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 401 , Rb 501 , Rb 801 and Rb 901 Each of these is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom. (((8))) The image forming apparatus according to (((7))), wherein the polyester resin having a dicarboxylic acid unit represented by formula (A2) and a diol unit represented by formula (B1) is a polyester resin having a dicarboxylic acid unit represented by the following (A2-3) and a diol unit represented by the following (B1-4). [ka] (((9))) An electrophotographic photoreceptor having a photosensitive layer that constitutes its surface, A cleaning device having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans at least residual toner particles from the surface of the electrophotographic photoreceptor, Equipped with, The photosensitive layer in the electrophotographic photoreceptor comprises a polyester resin (1) having a dicarboxylic acid unit (A) represented by the following formula (A) and a diol unit (B) represented by the following formula (B). The contact portion of the cleaning blade that comes into contact with the electrophotographic photoreceptor contains an impregnated and cured layer of a composition comprising isocyanate and at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers. A process cartridge that is attached to and detached from an image forming apparatus. [ka] In equation (A), Ar A1 and Ar A2 Each of these is an aromatic ring which may independently have substituents, L A is a single bond or a divalent linking group, n A1 It is 0, 1, or 2. In equation (B), Ar B1 and Ar B2 Each of these is an aromatic ring which may independently have substituents, L B is a single bond, oxygen atom, sulfur atom or -C(Rb 1 )(Rb 2 )- and n B1 Rb is 0, 1, or 2. 1 and Rb 2 Each of these is independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and Rb 1 and Rb 2 These may be bonded together to form a cyclic alkyl group.

[0332] The effects of the above embodiment are as follows: According to the disclosure in (((1))), compared to a specific image forming apparatus in which the photosensitive layer of the electrophotographic photoreceptor contains only polycarbonate resin, or in which the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor does not contain at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers, the cleaning apparatus is provided that has good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image forming when repeatedly forming low-image-density images in a high-temperature, high-humidity environment and when repeatedly forming high-image-density images in a low-temperature, low-humidity environment.

[0333] According to the disclosure in (((2))), compared to the case where the ratio of the total amount of F and Si present within 200 nm from the surface of the contact portion that contacts the electrophotographic photoreceptor to the total amount A present within 5 μm from the surface of the contact portion that contacts the electrophotographic photoreceptor is less than 75%, an image forming apparatus is provided that has good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image formation when low image density images are repeatedly formed in a high temperature and high humidity environment and when high image density images are repeatedly formed in a low temperature and low humidity environment. According to the disclosure in (((3))), compared to cases where the ratio of the total amount B of F and Si to the total amount A of F and Si is less than 85% or more than 95%, an image forming apparatus is provided that offers good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image forming when low image density images are repeatedly formed in a high-temperature, high-humidity environment and when high image density images are repeatedly formed in a low-temperature, low-humidity environment. According to the disclosure in (((4))), compared to the case where the total amount of F and Si C present on the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is less than 15 atm%, an image forming apparatus is provided that has good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image forming when low image density images are repeatedly formed in a high temperature and high humidity environment and when high image density images are repeatedly formed in a low temperature and low humidity environment. According to the disclosure in (((5))), compared to the case where the total amount D of F and Si present at a position 50 nm from the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is less than 0.3 atm%, an image forming apparatus is provided that has good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image forming when low image density images are repeatedly formed in a high temperature and high humidity environment and when high image density images are repeatedly formed in a low temperature and low humidity environment. According to the disclosure in (((6))), compared to the case where the 100% modulus at 23°C of the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is less than 5 MPa or greater than 23 MPa, an image forming apparatus is provided that has good cleaning performance and reduces wear of the electrophotographic photoreceptor in both image forming when repeatedly forming low image density images in a high-temperature, high-humidity environment and when repeatedly forming high image density images in a low-temperature, low-humidity environment.

[0334] According to the disclosure in (((7))), compared to the case in which the photosensitive layer of the electrophotographic photoreceptor contains a polyester resin having dicarboxylic acid units represented by (A1) and diol units represented by (B5) as the polyester resin (1), an image forming apparatus is provided that has good cleaning properties and reduces wear of the electrophotographic photoreceptor in both image formation when low image density images are repeatedly formed in a high temperature and high humidity environment and when high image density images are repeatedly formed in a low temperature and low humidity environment. According to the disclosure relating to (((8))), compared to the case where a polyester resin having dicarboxylic acid units represented by (A2) and diol units represented by (B1) has dicarboxylic acid units represented by (A2-3) and diol units represented by (B1-2), an image forming apparatus is provided that has good cleaning properties and reduces wear of the electrophotographic photoreceptor in both image forming when repeatedly forming low image density images in a high temperature and high humidity environment and when repeatedly forming high image density images in a low temperature and low humidity environment. According to the disclosure in (((9))), a process cartridge is provided which has good cleaning performance and reduced wear of the electrophotographic photoreceptor, in both cases of repeated image formation, whether low image density images are repeatedly formed in a high temperature and high humidity environment or high image density images are repeatedly formed in a low temperature and low humidity environment, compared to cases where the photosensitive layer of the electrophotographic photoreceptor contains only polycarbonate resin, or where the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor does not contain at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers. [Explanation of Symbols]

[0335] 1 Conductive substrate, 2 Undercoat layer, 3 Charge generation layer, 4 Charge transport layer, 5 Photosensitive layer, 12A photoreceptor, 12B photoreceptor

[0336] 10 Image forming apparatus, 12 Photoreceptor, 14 Charging member, 15 Charging device, 16 Electrostatic image forming apparatus, 18 Developing device, 20 Transfer member, 22 Cleaning device, 22A Cleaning blade, 24 Static eliminator, 26 Fixing device, 30A Recording medium, 31 Transfer device, 36 Control device

Claims

1. An electrophotographic photoreceptor having a photosensitive layer that constitutes its surface, A charging device for charging the surface of the electrophotographic photoreceptor, A static charge image forming apparatus for forming a static charge image on the surface of the charged electrophotographic photoreceptor, A developing apparatus that contains a developer and develops the electrostatic charge image formed on the surface of the electrophotographic photoreceptor by the developer as a toner image, A transfer device for transferring the toner image formed on the surface of the electrophotographic photoreceptor to the surface of a recording medium, A cleaning device having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans at least residual toner particles from the surface of the electrophotographic photoreceptor, Equipped with, The photosensitive layer in the electrophotographic photoreceptor comprises a polyester resin (1) having a dicarboxylic acid unit (A) represented by the following formula (A) and a diol unit (B) represented by the following formula (B). An image forming apparatus having an impregnated and cured layer of a composition comprising an isocyanate compound and at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers, on the contact portion of the cleaning blade that comes into contact with the electrophotographic photoreceptor. 【Chemistry 1】 In equation (A), Ar Ａ１ and Ar Ａ２ Each of these is an aromatic ring which may independently have substituents, L Ａ is a single bond or a divalent linking group, n Ａ１ It is 0, 1, or 2. In formula (B), Ar Ｂ１ and Ar Ｂ２ each independently represent an aromatic ring which may have a substituent, and L Ｂ represents a single bond, an oxygen atom, a sulfur atom or -C(Rb １ )(Rb ２ )-, and n Ｂ１ is 0, 1 or 2. Rb １ and Rb ２ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and Rb １ and Rb ２ may be bonded to each other to form a cyclic alkyl group.

2. The image forming apparatus according to claim 1, wherein the ratio of the total amount B of F and Si present within 200 nm from the surface of the contact portion in contact with the electrophotographic photoreceptor to the total amount A of F and Si present within 5 μm from the surface of the contact portion in contact with the electrophotographic photoreceptor is 75% or more.

3. The image forming apparatus according to claim 2, wherein the ratio of the total amount B of F and Si to the total amount A of F and Si is 85% or more and 95% or less.

4. The image forming apparatus according to claim 2, wherein the total amount C of F and Si present on the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is 15 atm% or more.

5. The image forming apparatus according to claim 2, wherein the total amount D of F and Si present at a position 50 nm from the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is 0.3 atm% or more.

6. The image forming apparatus according to claim 1, wherein the 100% modulus at 23°C of the surface of the contact portion of the cleaning blade that contacts the electrophotographic photoreceptor is 5 MPa or more and 23 MPa or less.

7. The image forming apparatus according to claim 1, wherein the photosensitive layer of the electrophotographic photoreceptor includes a polyester resin (1) having a dicarboxylic acid unit represented by (A2) below and a diol unit represented by (B1) below. 【Chemistry 2】 In equation (A2), n ２０１ and n ２０２ Each of these is an independent integer between 0 and 4, and n ２０１ Individual Ra ２０１ and n ２０２ Individual Ra ２０２ Each of these is independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. In equation (B1), Rb １０１ Rb is a branched alkyl group having 4 to 20 carbon atoms. ２０１ Rb is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ４０１ , Rb ５０１ , Rb ８０１ and Rb ９０１ Each of these is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

8. The image forming apparatus according to claim 7, wherein the polyester resin having a dicarboxylic acid unit represented by formula (A2) and a diol unit represented by formula (B1) is a polyester resin having a dicarboxylic acid unit represented by the following (A2-3) and a diol unit represented by the following (B1-4). 【Transformation 3】

9. An electrophotographic photoreceptor having a photosensitive layer that constitutes its surface, A cleaning device having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans at least residual toner particles from the surface of the electrophotographic photoreceptor, Equipped with, The photosensitive layer in the electrophotographic photoreceptor comprises a polyester resin (1) having a dicarboxylic acid unit (A) represented by the following formula (A) and a diol unit (B) represented by the following formula (B). The contact portion of the cleaning blade that comes into contact with the electrophotographic photoreceptor contains an impregnated and cured layer of a composition comprising isocyanate and at least one polymer selected from the group consisting of fluorine-based polymers and silicone-based polymers. A process cartridge that is attached to and detached from an image forming apparatus. 【Chemistry 4】 In equation (A), Ar Ａ１ and Ar Ａ２ Each of these is an aromatic ring which may independently have substituents, L Ａ is a single bond or a divalent linking group, n Ａ１ It is 0, 1, or 2. In equation (B), Ar Ｂ１ and Ar Ｂ２ Each of these is an aromatic ring which may independently have substituents, L Ｂ is a single bond, oxygen atom, sulfur atom or -C(Rb １ ) (Rb ２ ) - and n Ｂ１ Rb is 0, 1, or 2. １ and Rb ２ Each of these is independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and Rb １ and Rb ２ These may be bonded together to form a cyclic alkyl group.

Images