Electrophotographic belt and electrophotographic image formation device

Abstract

Provided are: an electrophotographic belt capable of forming good electrophotographic images over a long period of time; and an electrophotographic image formation device comprising the electrophotographic belt. This electrophotographic belt has a surface layer. The surface layer contains a resin A. The resin A has at least one structure selected from the group consisting of a structure represented by formula (1) and a structure represented by formula (2). The total contained amount of the portion obtained by excluding X1 and X2 from the structure represented by formula (1) and the portion obtained by excluding X3 and X4 from the structure represented by formula (2) is at least 10 mass% with respect to the mass of the surface layer.

Description

Electrophotographic belt and electrophotographic image forming apparatus

[0001] The present disclosure relates to an electrophotographic belt used in an electrophotographic image forming apparatus and an electrophotographic image forming apparatus employing the electrophotographic belt.

[0002] Electrophotographic image forming devices widely use a tandem method in which a toner image is formed on a photosensitive member, and the toner images of each color (Yellow, M, C, and K) are superimposed on an intermediate transfer belt, and then transferred all at once onto paper to obtain a full-color image.

[0003] Electrophotographic devices, which require high-speed printing and maintenance-free operation, require even more durable intermediate transfer belts. A widely adopted technology for tandem printing involves placing density-correcting toner images and color-shift measurement toner images on the intermediate transfer belt and measuring the density and color shift with a sensor to correct color density and color shift, thereby maintaining consistent color tone, gradation, and color shift even when printing multiple sheets. To achieve this correction, the light reflectance of the intermediate transfer belt surface must remain consistent over multiple print runs. However, there is a known problem: the adhesion of external additives used in toner can change the light reflectance of the intermediate transfer belt surface over multiple print runs, resulting in poor sensor measurement accuracy for the density-correcting toner image. Patent Document 1 addresses this issue by cleaning with a fur brush, where the inorganic external additives adhering to the brush abrade the surface of the intermediate transfer belt (ITB), thereby improving gloss reduction due to the adhesion.

[0004] JP 2019-040125 JP 08-044103

[0005] However, as a result of intensive research by the present inventors, it has been found that while the method described in Patent Document 1 is effective when only inorganic particles are used in the toner, when polymer particles such as polyvinylidene fluoride (PVDF) particles or styrene acrylic particles are used as particles to adhere to the toner surface as shown in Patent Document 2, it is difficult to maintain the light reflectivity of the surface of the intermediate transfer belt using the method described in Patent Document 1, because polymer particles do not have the abrasive power of inorganic particles.

[0006] Therefore, an object of the present disclosure is to provide an electrophotographic belt that can maintain the light reflectance of its surface and is less likely to change in color tone, gradation, or color misregistration even when a large number of sheets are printed.

[0007] The above object is achieved by the present disclosure as follows: That is, the electrophotographic belt according to the present disclosure is an electrophotographic belt having a surface layer, the surface layer containing a resin A, the resin A having at least one structure selected from the group consisting of a structure represented by formula (1) and a structure represented by formula (2), and the total content of a portion obtained by excluding X1 and X2 from the structure represented by formula (1) and a portion obtained by excluding X3 and X4 from the structure represented by formula (2) is 10 mass % or more based on the mass of the surface layer. [In the formula, X1 and X2 each independently represent a hydrogen atom, a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4), and n and m each independently represent an integer of 1 or greater, with 10≦m+n≦1800. Furthermore, any one of all X1s and X2s in the formula is a moiety having a structure represented by the following formula (3) or a moiety having a structure represented by the following formula (4). Furthermore, AH represents a hydrogen atom or an OH group.] [In the formula, X3 and X4 each independently represent a hydrogen atom, a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4), and p and q each independently represent an integer of 1 or greater, with 10≦p+q≦1800. Furthermore, any one of all of X3 and X4 in the formula is a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4). Furthermore, AH represents a hydrogen atom or an OH group.] [In the formula, A1 represents an organic group containing an aromatic group which may have a substituent, or an aliphatic group which may have a substituent, T is an integer of 2 to 6, and * represents a site connected to the structure represented by formula (1) or formula (2) directly or via a linking group.] [In the formula, A2 represents an organic group containing an aromatic group which may have a substituent or an aliphatic group which may have a substituent, R2 represents a hydrogen atom or a methyl group, U represents an integer of 2 to 6, and * represents a site connected to the structure represented by formula (1) or formula (2) directly or via a linking group.]

[0008] According to at least one aspect of the present disclosure, there is provided an electrophotographic belt capable of forming good electrophotographic images over a long period of time, and further, according to at least one aspect of the present disclosure, there is provided an electrophotographic image forming apparatus capable of stably forming high-quality electrophotographic images.

[0009] 1 is a schematic diagram illustrating the configuration of an electrophotographic image forming apparatus according to the present disclosure. 2 is a diagram illustrating an example of a cross-sectional configuration of an intermediate transfer belt according to the present disclosure.

[0010] In this specification, expressions such as "XX or more and YY or less" or "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints, unless otherwise specified. Furthermore, when a numerical range is described in stages, the upper and lower limits of each numerical range can be arbitrarily combined. Furthermore, in the present disclosure, expressions such as "at least one selected from the group consisting of XX, YY, and ZZ" mean any of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ.

[0011] Unless otherwise specified, the measured values ​​shown below are values ​​measured in an environment of a temperature of 23° C. and a humidity of 50% RH.

[0012] One embodiment of the present disclosure is an electrophotographic belt having a surface layer, the surface layer containing a resin A, the resin A having at least one structure selected from the group consisting of a structure represented by formula (1) and a structure represented by formula (2), and the total content of a portion obtained by excluding X1 and X2 from the structure represented by formula (1) and a portion obtained by excluding X3 and X4 from the structure represented by formula (2) is 10 mass % or more based on the mass of the surface layer. [In the formula, X1 and X2 each independently represent a hydrogen atom, a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4), and n and m each independently represent an integer of 1 or greater, with 10≦m+n≦1800. Furthermore, any one of all X1s and X2s in the formula is a moiety having a structure represented by the following formula (3) or a moiety having a structure represented by the following formula (4). Furthermore, AH represents a hydrogen atom or an OH group.] [In the formula, X3 and X4 each independently represent a hydrogen atom, a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4), and p and q each independently represent an integer of 1 or greater, with 10≦p+q≦1800. Furthermore, any one of all of X3 and X4 in the formula is a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4). Furthermore, AH represents a hydrogen atom or an OH group.] [In the formula, A1 represents an organic group containing an aromatic group which may have a substituent or an aliphatic group which may have a substituent, T is an integer of 2 to 6, and * represents a site connected to the structure represented by formula (1) or formula (2) directly or via a linking group.] [In the formula, A2 represents an organic group containing an aromatic group which may have a substituent or an aliphatic group which may have a substituent, R2 represents a hydrogen atom or a methyl group, U represents an integer of 2 to 6, and * represents a site connected to the structure represented by formula (1) or formula (2) directly or via a linking group.] One embodiment of the present disclosure is the electrophotographic belt described above, wherein the surface layer contains a total of 20 mass % or more of the structure represented by formula (1) excluding X1 and X2 and the structure represented by formula (2) excluding X3 and X4.

[0013] One embodiment of the present disclosure is an electrophotographic belt having a surface layer, the surface layer being a layer made of a cured product formed by curing (i) a compound having two or more (meth)acryloyl groups or a compound having two or more thiol groups, and (ii) at least one of trans 1,4-polyisoprene and 3,4-polyisoprene, and the surface layer having a total content of units derived from trans 1,4-polyisoprene and units derived from 3,4-polyisoprene of 10% by mass or more.

[0014] One embodiment of the present disclosure is the electrophotographic belt described above, wherein the cured product has a total content of units derived from trans 1,4-polyisoprene and units derived from 3,4-polyisoprene of 20% by mass or more based on the mass of the surface layer.

[0015] In one embodiment of the present disclosure, the Martens hardness determined by an indentation test of the surface layer is 12.0 N / mm ２ The electrophotographic belt described above is characterized in that:

[0016] One embodiment of the present disclosure is an electrophotographic image forming apparatus comprising: an image carrier that carries a toner image; and an intermediate transfer belt that carries and transports the toner image that has been primarily transferred from the image carrier to a transfer material for secondary transfer, wherein the intermediate transfer belt is the electrophotographic belt described above.

[0017] One embodiment of the present disclosure is the electrophotographic image forming apparatus described above, characterized in that a toner having polymer fine particles with a particle diameter of 1.0 μm or less adhered to the surface thereof is used.

[0018] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the following embodiments may be changed as appropriate depending on the configuration and various conditions of the device to which the present disclosure is applied, and are not intended to limit the scope of the present disclosure to only those.

[0019] [Electrophotographic Image Forming Apparatus] An electrophotographic image forming apparatus 100 shown in FIG. 1 is a schematic cross-sectional view of an electrophotographic image forming apparatus equipped with an electrophotographic member according to one embodiment of the present disclosure.

[0020] The electrophotographic image forming apparatus 100 shown in FIG. 1 is equipped with an intermediate transfer belt (electrophotographic belt) 7, which serves as an intermediate transfer member. Further, image forming units Py, Pm, Pc, and Pk for each color, yellow (Y), magenta (M), cyan (C), and black (K), are disposed along a flat portion of the intermediate transfer belt 7 in the moving direction of the belt. In FIG. 1, 1Y, 1M, 1C, and 1K respectively represent electrophotographic photosensitive members, 2Y, 2M, 2C, and 2K respectively represent charging rollers, 3Y, 3M, 3C, and 3K respectively represent laser exposure devices, 4Y, 4M, 4C, and 4K respectively represent developing units, and 5Y, 5M, 5C, and 5K respectively represent primary transfer rollers. Since the basic configuration of each image forming unit is the same, only the yellow image forming unit Py will be described in detail.

[0021] The yellow image forming unit Py has a drum-shaped electrophotographic photosensitive member 1Y (hereinafter also referred to as a "photosensitive drum" or a "first image carrier") as an image carrier. The photosensitive drum 1Y is formed by sequentially laminating a charge generating layer, a charge transport layer, and a surface protective layer on an aluminum cylinder as a base.

[0022] The yellow image forming unit Py also includes a charging roller 2Y as a charging means. By applying a charging bias to the charging roller 2Y, the surface of the photosensitive drum 1Y is uniformly charged.

[0023] A laser exposure device 3Y serving as an image exposure means is disposed above the photosensitive drum 1Y. The laser exposure device 3Y scans and exposes the uniformly charged surface of the photosensitive drum 1Y in accordance with image information, forming an electrostatic latent image of a yellow color component on the surface of the photosensitive drum 1Y.

[0024] The electrostatic latent image formed on the photosensitive drum 1Y is developed with toner as a developer by a developing unit 4Y as a developing means. The developing unit 4Y includes a developing roller 4Ya as a developer carrier and a regulating blade 4Yb as a developer amount regulating member, and contains yellow toner as a developer. The developing roller 4Ya, to which the yellow toner is supplied, is in light pressure contact with the photosensitive drum 1Y at the developing unit, and rotates in the forward direction with a speed difference from the photosensitive drum 1Y. The yellow toner transported to the developing unit by the developing roller 4Ya adheres to the electrostatic latent image formed on the photosensitive drum 1Y by applying a developing bias to the developing roller 4Ya. As a result, a visible image (yellow toner image) is formed on the photosensitive drum 1Y.

[0025] The intermediate transfer belt 7 is stretched around a drive roller 71, a tension roller 72, and a driven roller 73, and is in contact with the photosensitive drum 1Y to move (rotate) in the direction indicated by the arrow in the figure. A cross-sectional view of the intermediate transfer belt is shown in Figure 2. Here, reference numeral 21 denotes a base layer, and 22 denotes a surface protection layer.

[0026] The yellow toner image formed on the photosensitive drum (on the first image carrier) that has reached the primary transfer section Ty is primarily transferred onto the intermediate transfer belt 7 by the primary transfer body (primary transfer roller 5Y) that is arranged opposite the photosensitive drum 1Y via the intermediate transfer belt 7.

[0027] Similarly, the above image forming operation is performed in each of the magenta (M), cyan (C), and black (K) units Pm, Pc, and Pk as the intermediate transfer belt 7 moves, and four-color toner images of yellow, magenta, cyan, and black are layered on the intermediate transfer belt 7. The four color toner layers are transported as the intermediate transfer belt 7 moves, and at the secondary transfer portion T', they are transferred collectively by a secondary transfer roller 8 serving as secondary transfer means onto a transfer material S (hereinafter also referred to as the "second image carrier") that is transported at a predetermined timing. In such secondary transfer, a transfer voltage of several kV is usually applied to ensure a sufficient transfer rate.

[0028] The transfer material S is supplied to a conveying path by a pickup roller 13 from a cassette 12 in which the transfer material S is stored. The transfer material S supplied to the conveying path is conveyed to a secondary transfer portion T' in synchronization with the four-color toner image transferred to the intermediate transfer belt 7 by a conveying roller pair 14 and a registration roller pair 15.

[0029] The toner image transferred to the transfer material S is fixed by a fixing device 9 to become, for example, a full-color image. The fixing device 9 has a fixing roller 91 equipped with a heating means and a pressure roller 92, and fixes the unfixed toner image on the transfer material S by applying heat and pressure. Thereafter, the transfer material S is discharged to the outside of the apparatus by a pair of conveying rollers 16, a pair of discharging rollers 17, etc.

[0030] As described above, the electrical transfer process of the toner image is repeated from the photosensitive member to the intermediate transfer belt and from the intermediate transfer belt to the transfer material. Furthermore, by repeating recording onto a large number of transfer materials, the electrical transfer process is further repeated. Reference numeral 11 denotes a cleaning member.

[0031] [Color Tone Correction / Color Misalignment Correction] Color tone correction and color misalignment correction are performed by forming an image for detecting color tone or an image for detecting color misalignment on the electrophotographic belt and reading the image on the electrophotographic belt via a sensor. In this case, the reflectance of the electrophotographic belt itself is also read as a background, so if the reflectance of the electrophotographic belt changes too much, it becomes difficult to determine whether the change is due to a change in the reflectance of the electrophotographic belt or a change in the toner image, and there is a possibility that the correction cannot be performed accurately.

[0032] [Electrophotographic Belt] The electrophotographic belt of the present disclosure has a base layer and a surface layer on the base layer. That is, the electrophotographic belt of the present disclosure is an electrophotographic belt having a surface layer, the surface layer containing a resin A, the resin A having at least one structure selected from the group consisting of structures represented by formula (1) and structures represented by formula (2), and the total content of the portion obtained by excluding X1 and X2 from the structure represented by formula (1) and the portion obtained by excluding X3 and X4 from the structure represented by formula (2) is 10 mass % or more based on the mass of the surface layer. [In the formula, X1 and X2 each independently represent a hydrogen atom, a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4), and n and m each independently represent an integer of 1 or greater, with 10≦m+n≦1800. Furthermore, any one of all X1s and X2s in the formula is a moiety having a structure represented by the following formula (3) or a moiety having a structure represented by the following formula (4). Furthermore, AH represents a hydrogen atom or an OH group.] [In the formula, X3 and X4 each independently represent a hydrogen atom, a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4), and p and q each independently represent an integer of 1 or greater, with 10≦p+q≦1800. Furthermore, any one of all of X3 and X4 in the formula is a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4). Furthermore, AH represents a hydrogen atom or an OH group.] [In the formula, A1 represents an organic group containing an aromatic group which may have a substituent or an aliphatic group which may have a substituent, T is an integer of 2 to 6, and * represents a site connected to the structure represented by formula (1) or formula (2) directly or via a linking group.] [In the formula, A2 represents an organic group containing an aromatic group which may have a substituent or an aliphatic group which may have a substituent, R2 represents a hydrogen atom or a methyl group, U represents an integer of 2 to 6, and * represents a site connected to the structure represented by formula (1) or formula (2) directly or via a linking group.]

[0033] The material of the base layer is not particularly limited, and well-known materials can be used depending on the application of the electrophotographic member. Details will be described later. The surface layer contains a resin A having at least one structure selected from the group consisting of a structure represented by formula (1) and a structure represented by formula (2). Resin A includes a resin obtained by polymerizing a (meth)acrylate monomer or a resin obtained by polymerizing a polyfunctional thiol. The inclusion of such a resin improves the adhesion and mechanical strength between the surface layer and the base layer.

[0034] The content of resin A in the surface layer is not particularly limited, but is preferably 20 to 90% by mass relative to the mass of the total solids of the surface layer in order to impart excellent strength to the surface layer and to impart excellent toner releasability to the outer surface of the surface layer. Examples of (meth)acrylic monomers include the following (i) acrylate, (ii) methacrylate, (iii) urethane acrylate, and (iv) urethane methacrylate. Polymerizable monomers that are commercially available as paints can also be used. (i) At least one acrylate selected from the group consisting of pentaerythritol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, alkyl acrylate, benzyl acrylate, phenyl acrylate, ethylene glycol diacrylate, and bisphenol A diacrylate. (ii) at least one methacrylate selected from the group consisting of pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, ditrimethylolpropane tetramethacrylate, dipentaerythritol hexamethacrylate, alkyl methacrylate, benzyl methacrylate, phenyl methacrylate, ethylene glycol dimethacrylate, and bisphenol A dimethacrylate. (iii) at least one acrylate selected from the group consisting of polyether-based urethane acrylates and polyester-based urethane acrylates. (iv) at least one methacrylate selected from the group consisting of polyether-based urethane methacrylates and polyester-based urethane methacrylates.Examples of polyfunctional thiols include secondary thiols such as pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinane-2,4,6-trione, and trimethylolpropane tris(3-mercaptobutyrate); and 3-(3-mercaptopropoxy)-2,2-bis-(3-mercaptopropoxymethyl)-propan-1-ol and trimethylolpropane. Examples of primary thiols include dipropanethiol, 2,2-bis[(3-sulfanylpropoxy)methyl]butan-1-ol, and pentaerythritoltetrapropanethiol, 3-{3-(3-mercapto-propoxy)-2,2-bis-[(3-mercaptopropoxy)methyl]propoxy}-propan-1-ol.

[0035] In addition, in order to form a (meth)acrylic resin from such a polymerizable monomer, there is a method in which a photopolymerization initiator is added and polymerization is carried out by electron beam or ultraviolet light.

[0036] Examples of the photopolymerization initiator include radical-generating photopolymerization initiators such as benzophenone, thioxanthone-based, benzyl dimethyl ketal, α-hydroxyketone, α-hydroxyalkylphenone, α-aminoketone, α-aminoalkylphenone, monoacylphosphine oxide, bisacylphosphine oxide, hydroxybenzophenone, aminobenzophenone, titanocene-based, oxime ester, and oxyphenylacetic acid ester.

[0037] [Surface Layer] The surface layer of an electrophotographic belt is generally required to have low adhesion and slipperiness. Fluorine materials and silicone materials have been used as such materials. Organofluorine materials and silicone materials have low surface free energy, making them capable of achieving low adhesion and slipperiness. However, in recent years, significant restrictions on organofluorine materials have been discussed in some countries. Furthermore, silicone materials sometimes contain cyclic siloxanes such as D4, D5, and D6 as unreacted raw materials, but cyclic siloxanes are also restricted in some countries. Therefore, there is a demand for materials that can achieve low adhesion and slipperiness without relying on organofluorine or silicone materials.

[0038] [Polyisoprene] In the present disclosure, polyisoprene with a specific structure is used in the surface layer of an electrophotographic belt. Polyisoprene typically exists in various isomers, but attempts have been made to provide an elastic intermediate transfer belt (ITB) by using polyisoprene, which contains 90% or more of cis isomers and has properties similar to natural rubber, in the surface layer of the intermediate transfer belt. To enable such an elastic layer to be used as a belt, the elastic layer made of polyisoprene must have a thickness of 100 μm or more. The present disclosure does not relate to the use of polyisoprene in such an elastic layer, but rather to the use of polyisoprene in a surface layer.

[0039] [Base Layer] The material of the base layer may be any known material for electrophotographic materials and is not particularly limited. For example, resins with excellent mechanical strength such as nylon, polyphenyl sulfide, polyimide, polyamideimide, polyether ether ketone, and polyurethane elastomer are used. The thickness of the base layer is not particularly limited, but is preferably 20 μm to 500 μm, more preferably 40 μm to 300 μm, from the viewpoints of strength, flexibility, and heat capacity. Furthermore, a conductive filler such as carbon black or an ionic conductive agent may be added to the resin to impart semiconductivity.

[0040] The present disclosure will be described in more detail below using examples and comparative examples. The present disclosure is not limited in any way by the following examples, as long as it does not deviate from the gist of the disclosure. In the following description of the examples, "parts" are based on mass unless otherwise specified.

[0041] [Example 1] (Production example of base layer α) Using a twin-screw kneader, 85% by mass of nylon 12 (Rilsamid AMN P20 TL, manufactured by Arkema) and 15% by mass of acetylene black (Denka Black, manufactured by Denka) were melt-kneaded to prepare raw material α-1. Raw material α-1 was introduced into an extruder and an annular die was connected to obtain a seamless belt α as the base layer α.

[0042] (Production Example of Surface Layer Paint A1) The following four compounds were mixed for 6 hours using a mix rotor in a light-shielded state to obtain a surface layer paint A1: 60 parts by mass of trimethylolpropane tris(3-mercaptopropionate) manufactured by Tokyo Chemical Industry Co., Ltd. 40 parts by mass of trans-1,4-polyisoprene (99% by mass, Mw 50,000, 1% by mass is 1,2-cis polyisoprene) manufactured by Sigma-Aldrich Co., Ltd. 6 parts by mass of 1-hydroxycyclohexyl phenyl ketone manufactured by Tokyo Chemical Industry Co., Ltd. 100 parts by mass of toluene manufactured by Kishida Chemical Co., Ltd.

[0043] (Production Example of Electrophotographic Belt 1) The surface layer paint A1 was applied to a seamless belt α, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt α1 as the electrophotographic belt 1.

[0044] [Example 2] (Production example of base layer β) Using a twin-screw kneader, 85% by mass of polyphenyl sulfide (E2180, manufactured by Toray Industries, Inc.), 17% by mass of acetylene black (Denka Black, manufactured by Denka Corporation), and a graft copolymer of ethylene-glycidyl methacrylate copolymer / styrene-acrylonitrile copolymer (Modiper A4400, manufactured by NOF Corp.) were melt-kneaded to prepare raw material β-1. Raw material β-1 was introduced into an extruder and an annular die was connected to obtain a seamless belt β as the base layer β.

[0045] (Example of Production of 3,4-Polyisoprene) The following two compounds were placed in a flask: Toluene (Kishida Chemical) 13 ml Isoprene (Tokyo Chemical Industry) 2 ml Subsequently, a condenser was attached, and the mixture was stirred in a water-ethanol-dry ice bath while maintaining the temperature at -30°C, and the following two compounds were poured into it. The reaction was carried out at -30°C, and the nitrogen substitution was stopped to terminate the reaction. 3,4-polyisoprene (80% by mass, 20% by mass being 1,2-cis polyisoprene) was obtained by evaporating the solvent. Note that 3,4-polyisoprene with different weight-average molecular weights Mw was obtained by controlling the reaction time from 10 minutes to 2 hours. Tris(2,2'-bipyridine) iron (II) dichloride (Matrix) 5 μl Methylaluminoxane 10 wt % toluene solution (Sigma-Aldrich) 50 μl

[0046] (Production Example of Surface Layer Paint A2) Surface layer paint A2 was obtained in the same manner as surface layer paint A1, except that the compounds used in surface layer paint A1 were changed to the following compounds and parts by mass: Trimethylolpropane tris(3-mercaptopropionate) manufactured by Tokyo Chemical Industry Co., Ltd. 75 parts by mass 3,4-Polyisoprene (80% by mass, Mw 5,000, 20% by mass is 1,2-cis-polyisoprene) 25 parts by mass 1-Hydroxycyclohexylphenylketone manufactured by Tokyo Chemical Industry Co., Ltd. 6 parts by mass Toluene manufactured by Kishida Chemical Co., Ltd. 100 parts by mass

[0047] (Production Example of Electrophotographic Belt 2) The surface layer coating material A2 was applied to a seamless belt β, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt β2 as the electrophotographic belt 2.

[0048] [Example 3] (Production example of surface layer paint A3) Surface layer paint A3 was obtained in the same manner as surface layer paint A1, except that the compounds used in surface layer paint A1 were changed to the following compounds and parts by mass: Hexafunctional acrylate (Aronix M-405) manufactured by Toagosei Co., Ltd. 90 parts by mass; trans-1,4 polyisoprene (99% by mass, Mw 50,000, 1% by mass is 1,2-cis polyisoprene) manufactured by Sigma-Aldrich Co., Ltd. 10 parts by mass; 1-hydroxycyclohexyl phenyl ketone manufactured by Tokyo Chemical Industry Co., Ltd. 6 parts by mass; Toluene manufactured by Kishida Chemical Co., Ltd. 100 parts by mass.

[0049] (Production Example of Electrophotographic Belt 3) The surface layer coating material A3 was applied to a seamless belt β, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt β3 as the electrophotographic belt 3.

[0050] [Example 4] (Production example of surface layer paint A4) Surface layer paint A4 was obtained in the same manner as surface layer paint A1, except that the compounds used in surface layer paint A1 were changed to the following compounds and parts by mass: Trifunctional acrylate (Aronix M-309) manufactured by Toa Gosei Co., Ltd. 75 parts by mass 3,4-Polyisoprene (80% by mass, Mw 50,000, 20% by mass is 1,2-cis-polyisoprene) 25 parts by mass 1-Hydroxycyclohexyl phenyl ketone manufactured by Tokyo Chemical Industry Co., Ltd. 6 parts by mass Toluene manufactured by Kishida Chemical Co., Ltd. 100 parts by mass

[0051] (Production Example of Electrophotographic Belt 4) The surface layer paint A4 was applied to a seamless belt α, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt α4 as the electrophotographic belt 4.

[0052] [Example 5] (Production example of surface layer paint A5) Surface layer paint A5 was obtained in the same manner as surface layer paint A1, except that the compounds used in surface layer paint A1 were changed to the following compounds and parts by mass: Trifunctional acrylate (Aronix M-306) manufactured by Toa Gosei Co., Ltd. 87.5 parts by mass 3,4-polyisoprene (80% by mass, Mw 20,000, 20% by mass is 1,2-cis-polyisoprene) 12.5 parts by mass 1-hydroxycyclohexyl phenyl ketone manufactured by Tokyo Chemical Industry Co., Ltd. 6 parts by mass Toluene manufactured by Kishida Chemical Co., Ltd. 100 parts by mass

[0053] (Production Example of Electrophotographic Belt 5) The surface layer paint A5 was applied to a seamless belt α, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt α5 as the electrophotographic belt 5.

[0054] [Example 6] (Production example of surface layer paint A6) Surface layer paint A6 was obtained in the same manner as surface layer paint A1, except that the compounds used in surface layer paint A1 were changed to the following compounds and parts by mass: 88 parts by mass of tetrafunctional acrylate (Aronix M-408) manufactured by Toagosei Co., Ltd. 10 parts by mass of 3,4-polyisoprene (80% by mass, Mw 10,000, 20% by mass is 1,2-cis polyisoprene) 2 parts by mass of trans-1,4-polyisoprene manufactured by Sigma-Aldrich Co., Ltd. 6 parts by mass of 1-hydroxycyclohexyl phenyl ketone manufactured by Tokyo Chemical Industry Co., Ltd. 100 parts by mass of toluene manufactured by Kishida Chemical Co., Ltd.

[0055] (Production Example of Electrophotographic Belt 6) The surface layer paint A6 was applied to a seamless belt β, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt β6 as the electrophotographic belt 6.

[0056] [Example 7] (Production example of base layer γ) The following three compounds were melt-kneaded using a twin-screw kneader to obtain raw material γ-1: 99 parts by mass of Elastollan ET155D manufactured by BASF 1 part by mass of poly(ethylene oxide) Mw 150,000 manufactured by Sigma-Aldrich 0.1 part by mass of lithium perchlorate manufactured by Tokyo Chemical Industry Co., Ltd. Raw materials γ-1 and α-1 were each placed in separate extruders, which were connected to a cylindrical die for co-extrusion, and co-extrusion was carried out so that the layer derived from raw material γ-1 was the outer layer and the layer derived from raw material α-1 was the inner layer, thereby obtaining a seamless belt γ as the base layer γ.

[0057] (Production Example of Surface Layer Paint A7) Surface layer paint A7 was obtained in the same manner as surface layer paint A1, except that the compounds used in surface layer paint A1 were changed to the following compounds and parts by mass: Urethane acrylate (UA-290™) manufactured by Shin-Nakamura Chemical Co., Ltd. 90 parts by mass Trans-1,4-polyisoprene (99% by mass, Mw 50,000, 1% by mass is 1,2-cis-polyisoprene) manufactured by Sigma-Aldrich Co., Ltd. 10 parts by mass 1-Hydroxycyclohexylphenyl ketone manufactured by Tokyo Chemical Industry Co., Ltd. 6 parts by mass Toluene manufactured by Kishida Chemical Co., Ltd. 100 parts by mass

[0058] (Production Example of Electrophotographic Belt 7) The surface layer paint A7 was applied to a seamless belt γ, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt γ7 as the electrophotographic belt 7.

[0059] [Comparative Example 1] (Production Example of Surface Layer Paint B1) Surface layer paint B1 was obtained in the same manner as surface layer paint A1, except that the compounds used in surface layer paint A1 were changed to the following compounds and parts by mass: Trimethylolpropane tris(3-mercaptopropionate) manufactured by Tokyo Chemical Industry Co., Ltd. 85 parts by mass Cis-1,4-polyisoprene (97% by mass, Mw 40,000, 3% by mass is 1,2-cis-polyisoprene) manufactured by Sigma-Aldrich Co., Ltd. 15 parts by mass 1-Hydroxycyclohexyl phenyl ketone manufactured by Tokyo Chemical Industry Co., Ltd. 6 parts by mass Toluene manufactured by Kishida Chemical Co., Ltd. 100 parts by mass

[0060] (Example of Manufacturing Electrophotographic Belt 11) The surface layer coating material B1 was applied to a seamless belt α, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt α11 as the electrophotographic belt 11.

[0061] [Comparative Example 2] (Production Example of Surface Layer Paint B2) Surface layer paint B2 was obtained in the same manner as surface layer paint A1, except that the compounds used in surface layer paint A1 were changed to the following compounds and parts by mass: Trifunctional acrylate (Aronix M-306) manufactured by Toagosei Co., Ltd. 89 parts by mass Cis-1,4-polyisoprene (97% by mass, Mw 40,000, 3% by mass is 1,2-cis-polyisoprene) manufactured by Sigma-Aldrich Co., Ltd. 21 parts by mass 1-Hydroxycyclohexyl phenyl ketone manufactured by Tokyo Chemical Industry Co., Ltd. 6 parts by mass Toluene manufactured by Kishida Chemical Co., Ltd. 100 parts by mass

[0062] (Example of Manufacturing Electrophotographic Belt 12) The surface layer coating material B2 was applied to the seamless belt β, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt β12 as the electrophotographic belt 12.

[0063] [Comparative Example 3] (Production Example of Surface Layer Coating B3) Surface layer coating B3 was obtained in the same manner as surface layer coating A1, except that the compounds used in surface layer coating A1 were changed to the following compounds and parts by mass: Trimethylolpropane tris(3-mercaptopropionate) manufactured by Tokyo Chemical Industry Co., Ltd. 87 parts by mass Cis-1,4-polyisoprene (97% by mass, Mw 40,000, 3% by mass is 1,2-cis-polyisoprene) manufactured by Sigma-Aldrich Co., Ltd. 5 parts by mass Trans-1,4-polyisoprene (99% by mass, Mw 50,000, 1% by mass is 1,2-cis-polyisoprene) manufactured by Sigma-Aldrich Co., Ltd. 8 parts by mass 1-Hydroxycyclohexylphenylketone manufactured by Tokyo Chemical Industry Co., Ltd. 6 parts by mass Toluene manufactured by Kishida Chemical Co., Ltd. 100 parts by mass

[0064] (Example of Manufacturing Electrophotographic Belt 13) The surface layer coating material B3 was applied to the seamless belt β, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt β13 as the electrophotographic belt 13.

[0065] [Comparative Example 4] (Production Example of Surface Layer Coating B4) Surface layer coating B4 was obtained in the same manner as surface layer coating A1, except that the compounds used in surface layer coating A1 were changed to the following compounds and parts by mass: Trifunctional acrylate (Aronix M-306) manufactured by Toagosei Co., Ltd. 90 parts by mass 3,4-Polyisoprene (80% by mass, 20% by mass is 1,2-cis polyisoprene) 5 parts by mass Trans-1,4-Polyisoprene (99% by mass, Mw 50,000, 1% by mass is 1,2-cis polyisoprene) manufactured by Sigma-Aldrich Co., Ltd. 6 parts by mass 1-Hydroxycyclohexyl phenyl ketone manufactured by Tokyo Chemical Industry Co., Ltd. 100 parts by mass Toluene manufactured by Kishida Chemical Co., Ltd.

[0066] (Example of Manufacturing Electrophotographic Belt 14) The surface layer paint B4 was applied to the seamless belt β, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt β14 as the electrophotographic belt 14.

[0067] [Comparative Example 5] (Production Example of Surface Layer Coating B5) Surface layer coating B5 was obtained in the same manner as surface layer coating A1, except that the compounds used in surface layer coating A1 were changed to the following compounds and parts by mass: Trifunctional acrylate (Aronix M-306) manufactured by Toagosei Co., Ltd. 92 parts by mass Trans-1,4-polyisoprene (99% by mass, Mw 50,000, 1% by mass is 1,2-cis-polyisoprene) manufactured by Sigma-Aldrich Co., Ltd. 8 parts by mass 1-Hydroxycyclohexylphenyl ketone manufactured by Tokyo Chemical Industry Co., Ltd. 6 parts by mass Toluene manufactured by Kishida Chemical Co., Ltd. 100 parts by mass

[0068] (Production Example of Electrophotographic Belt 15) The surface layer paint B5 was applied to the seamless belt β, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt β15 as the electrophotographic belt 15.

[0069] [Comparative Example 6] (Production Example of Surface Layer Paint B6) Surface layer paint B6 was obtained in the same manner as surface layer paint A1, except that the compounds used in surface layer paint A1 were changed to the following compounds and parts by mass: Trifunctional acrylate (Aronix M-306) manufactured by Toa Gosei Co., Ltd. 90 parts by mass 3,4-Polyisoprene (80% by mass, Mw 20,000, 20% by mass is 1,2-cis-polyisoprene) 10 parts by mass 1-Hydroxycyclohexyl phenyl ketone manufactured by Tokyo Chemical Industry Co., Ltd. 6 parts by mass Toluene manufactured by Kishida Chemical Co., Ltd. 100 parts by mass

[0070] (Example of Manufacturing Electrophotographic Belt 16) The surface layer paint B6 was applied to the seamless belt β, and the solvent was dried for 10 minutes at 80° C. Thereafter, UV irradiation was performed with an integrated light amount of 2000 mJ at a wavelength of 365 nm, thereby obtaining a seamless belt β16 as the electrophotographic belt 16.

[0071] The formulations of Examples 1 to 7 and Comparative Examples 1 to 6 are shown in Table 1. In Table 1, Chemical (10), Chemical (11), and Chemical (12) refer to the compound represented by the following formula (10), the compound represented by the following formula (11), and the compound represented by the following formula (12), respectively.

[0072] (Evaluation of raw material polyisoprene) The weight average molecular weight Mw of polyisoprene can be measured using a commercially available device in accordance with JIS K 7252-2. In the present disclosure, the measurement was performed under the following measurement conditions, but is not limited to these. Device: GPC manufactured by Showa Denko Column: KF800 series manufactured by Showa Denko Liquid: THF (for high performance liquid chromatography) manufactured by Kishida Chemical Standard particles: Easivial series manufactured by Agilent

[0073] (Physical Properties of Electrophotographic Belt) The Martens hardness of the outer surface of the surface layer can be evaluated by the method shown below. The obtained electrophotographic belt is cut into a sheet measuring 20 mm in length and 20 mm in width, and the Martens hardness and elastic deformation power can be measured by nanoindentation. Using a commercially available device conforming to ISO 14577, calculations can be made from the obtained load-displacement curve in accordance with the procedure of the indentation test specified in ISO 14577. In the present disclosure, a nanoindenter device conforming to the above ISO standard (PICODENTOR HM500 manufactured by FISCHER) was used. In the present disclosure, measurements were made using the above measurement device and the following measurement conditions, but the present disclosure is not limited to these. Measurement environment: 23°C, 40% humidity Indenter: Vickers indenter Measurement load: 260 μN Number of measurement points: average of 3 points The measurement results are shown in Table 2. When the Martens hardness determined by the indentation test of the above surface layer was 12.0 N / mm ２ It is preferable that this is equal to or greater than this.

[0074] (Evaluation of Electrophotographic Belt) A copier (product name: iR ADVANCE C5560F, manufactured by Canon Inc.) was used as the electrophotographic apparatus, and the electrophotographic belts of the examples and comparative examples were each installed as an intermediate transfer belt. It is preferable to use a toner having polymer fine particles with a particle diameter of 1.0 μm or less adhered to its surface. In this example, a toner having styrene acrylic particles with a particle diameter of 1.0 μm or less adhered to its surface, which was prepared with reference to Patent Document 2, was used to print a standard image according to JIS X 9201-2001, and the L*, a*, and b* of each of the 16 color patch images were measured using an X-Rite portable spectrophotometer. After printing 10,000 sheets using A4-sized paper, the copier was turned off for 12 hours, and 10,000 sheets were printed again. This process was repeated, and L*, a*, and b* were measured every 1,000 sheets, and printing was continued until 100,000 sheets were printed. The color difference (ΔE76) was calculated by calculating the difference between the L*, a*, and b* values ​​of the 1000th image and the L*, a*, and b* values ​​of the 1000th image, squaring each of these values, and taking the square root of the sum. A color difference of 2.0 or more on the 100,000th image was evaluated as ×, a difference of 1.0 or more but less than 2.0 was evaluated as ◯, and a difference of less than 1.0 was evaluated as ⊚. The evaluation results are shown in Table 2.

[0075]

[0076] (Regarding color difference evaluation results) In the Examples, there was little color difference, i.e., little color variation, even after printing 100,000 sheets. Although the cause of this is not fully understood, it is believed that in the Examples, the use of polyisoprene with a specific structure as the raw material for the surface layer resulted in the action of methyl groups, resulting in low adhesion. This is because, when the electrophotographic belt was observed with an optical microscope after printing 100,000 sheets, it was confirmed that in the Examples, the styrene acrylic particles used in the toner had hardly adhered to the electrophotographic belt, while in the Comparative Examples, a large amount of styrene acrylic particles had adhered. This difference in adhesion is thought to have reduced noise when detecting the toner image for density correction placed on the belt in the Examples, allowing for accurate correction, thereby suppressing color variation.

[0077] The present invention is not limited to the above-described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to apprise the public of the scope of the present invention.

[0078] This application claims priority based on Japanese Patent Application No. 2024-088207 filed on May 30, 2024 and Japanese Patent Application No. 2025-083580 filed on May 19, 2025, the entire contents of which are incorporated herein by reference.

[0079] Py: yellow image forming unit, Pm: magenta image forming unit, Pc: cyan image forming unit, Pk: black image forming unit, 1Y: yellow photosensitive drum, 1M: magenta photosensitive drum, 1C: cyan photosensitive drum, 1K: black photosensitive drum, 4Y: yellow developing unit, 4M: magenta developing unit, 4C: cyan developing unit, 4K: black developing unit, 5Y, 5M, 5C, 5K: primary transfer rollers, Ty, Tm, Tc, Tk: primary transfer section, 73: driven roller, 100: electrophotographic image forming apparatus, 2Y, 2M, 2C, 2K: charging rollers, 3Y, 3M, 3C, 3K: laser exposure device, 11: cleaning member, 12: cassette, 15: pair of registration rollers, 7: intermediate transfer belt, 8: secondary transfer roller, 9: fixing unit, 91: fixing roller, 92: pressure roller, S: transfer material

Claims

1. An electrophotographic belt having a surface layer, wherein the surface layer contains a resin A, and the resin A has at least one structure selected from the group consisting of a structure represented by formula (1) and a structure represented by formula (2), and the total content of the portion obtained by excluding X1 and X2 from the structure represented by formula (1) and the portion obtained by excluding X3 and X4 from the structure represented by formula (2) is 10% by mass or more based on the mass of the surface layer. [In the formula, X1 and X2 each independently represent a hydrogen atom, a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4), and n and m each independently represent an integer of 1 or greater, with 10≦m+n≦1800. Furthermore, any one of all X1s and X2s in the formula is a moiety having a structure represented by the following formula (3) or a moiety having a structure represented by the following formula (4). Furthermore, AH represents a hydrogen atom or an OH group.] [In the formula, X3 and X4 each independently represent a hydrogen atom, a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4), and p and q each independently represent an integer of 1 or greater, with 10≦p+q≦1800. Furthermore, any one of all of X3 and X4 in the formula is a moiety having a structure represented by the following formula (3), or a moiety having a structure represented by the following formula (4). Furthermore, AH represents a hydrogen atom or an OH group.] [In the formula, A1 represents an organic group containing an aromatic group which may have a substituent or an aliphatic group which may have a substituent, T is an integer of 2 to 6, and * represents a site connected to the structure represented by formula (1) or formula (2) directly or via a linking group.] [In the formula, A2 represents an organic group containing an aromatic group which may have a substituent or an aliphatic group which may have a substituent, R2 represents a hydrogen atom or a methyl group, U represents an integer of 2 to 6, and * represents a site connected to the structure represented by formula (1) or formula (2) directly or via a linking group.] 2. The electrophotographic belt according to claim 1, wherein the total content of the structure of formula (1) excluding X1 and X2 and the structure of formula (2) excluding X3 and X4 in the surface layer is 20% by mass or more.

3. An electrophotographic belt having a surface layer, the surface layer being a layer made of a cured product formed by curing (i) a compound having two or more (meth)acryloyl groups or a compound having two or more thiol groups, and (ii) at least one of trans 1,4-polyisoprene and 3,4-polyisoprene, wherein the total content of units derived from trans 1,4-polyisoprene and units derived from 3,4-polyisoprene in the surface layer is 10% by mass or more.

4. The electrophotographic belt according to claim 3, wherein the cured product has a total content of units derived from trans 1,4-polyisoprene and units derived from 3,4-polyisoprene of 20% by mass or more based on the mass of the surface layer.

5. The Martens hardness of the surface layer determined by an indentation test is 12.0 N / mm ２ 5. The electrophotographic belt according to claim 1, wherein the electrophotographic belt is a belt having a thickness of 100 nm or less.

6. An electrophotographic image forming apparatus comprising an image carrier that carries a toner image, and an intermediate transfer belt that carries and transports the toner image that has been primarily transferred from the image carrier to a transfer material for secondary transfer, wherein the intermediate transfer belt is an electrophotographic belt as defined in any one of claims 1 to 5.

7. The electrophotographic image forming apparatus according to claim 6, wherein the toner has polymeric fine particles with a particle diameter of 1.0 μm or less adhered to the surface thereof.

Images