Electrophotographic member and electrophotographic image forming device

Abstract

Provided is an electrophotographic member excellent in transferability over a long period of time. An electrophotographic member according to the present invention comprises a base layer and a surface layer on the base layer, said electrophotographic member being characterized in that: the surface layer includes at least one selected from the group consisting of (meth)acrylic resins and (meth)acrylic rubber; a plurality of resin particles are present on the outer surface of the surface layer; at least some particles among the plurality of resin particles are in direct contact with the outer surface of the surface layer; a portion of the outer surface of the electrophotographic member is constituted by the resin particles; protrusions and recesses formed by the resin particles are present on the outer surface of the electrophotographic member; and the resin particles include a (meth)acrylic-modified silicone resin.

Description

Electrophotographic member and electrophotographic image forming apparatus

[0001] The present disclosure relates to an electrophotographic member used in an electrophotographic image forming apparatus such as a copying machine or a printer, and to the electrophotographic image forming apparatus.

[0002] Electrophotographic image forming apparatuses capable of forming color images widely employ a tandem system in which toner images of YMCK colors are superimposed on an intermediate transfer belt, which is an electrophotographic belt, and then transferred onto paper in one go to obtain a full-color image. To achieve even higher image quality, such image forming apparatuses sometimes use intermediate transfer belts having at least one elastic layer (hereinafter also referred to as elastic intermediate transfer belts). Elastic intermediate transfer belts having an elastic layer as a surface layer can have insufficient toner releasability and reduced transfer efficiency, so a configuration in which resin particles are embedded in the outer surface of the elastic layer and exposed to the surface is sometimes used.

[0003] Patent Document 1 discloses a configuration in which an acrylic rubber is used as the elastic layer and silicone resin particles with excellent toner releasability are used as the resin particles on the outer surface. Patent Document 2 discloses a configuration in which an acrylic rubber is used as the elastic layer and acrylic resin particles in addition to silicone resin particles are used as the resin particles embedded in the outer surface of the elastic layer, thereby further improving transferability.

[0004] JP 2012-208485 A JP 2014-145817 A

[0005] However, according to the inventors' investigations, when an acrylic rubber is used as the elastic layer and silicone resin particles are used as the resin particles, as disclosed in Patent Documents 1 and 2, the silicone resin particles may fall off over a long period of use. As a result, even if the transferability is excellent at the beginning of use, the transferability may deteriorate over a long period of use. Furthermore, as disclosed in Patent Document 2, when acrylic resin particles are used, the acrylic resin particles do not fall off, but the toner release effect of the acrylic resin particles is weaker than that of the silicone resin particles, and the transferability may deteriorate.

[0006] At least one aspect of the present disclosure is directed to providing an electrophotographic member that exhibits excellent transferability over a long period of time by achieving both high levels of toner releasability and high levels of adhesion between a surface layer and inorganic particles. Also, at least one aspect of the present disclosure is directed to providing an electrophotographic image forming apparatus that can stably form high-quality electrophotographic images.

[0007] According to at least one aspect of the present disclosure, there is provided an electrophotographic member having a base layer and a surface layer on the base layer, wherein the surface layer contains at least one selected from the group consisting of a (meth)acrylic resin and a (meth)acrylic rubber, a plurality of resin particles are present on the outer surface of the surface layer, at least some of the plurality of resin particles are in direct contact with the outer surface of the surface layer, a portion of the outer surface of the electrophotographic member is made of the resin particles, and the outer surface of the electrophotographic member has irregularities formed by the resin particles, and the resin particles contain a (meth)acrylic-modified silicone resin.

[0008] According to at least one aspect of the present disclosure, there is provided an electrophotographic image forming apparatus comprising: an image forming unit including an image carrier, a charging means, an image exposure means, and a developing means; an intermediate transfer body; a primary transfer member that primarily transfers a toner image formed on the image carrier onto the intermediate transfer body; and a secondary transfer member that secondarily transfers the toner image on the intermediate transfer body onto a recording material, wherein the developing means is provided with a toner storage section that stores toner, and the intermediate transfer body is the electrophotographic member of the present disclosure.

[0009] According to at least one aspect of the present disclosure, there is provided an electrophotographic member having excellent transferability over a long period of time, and also, 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.

[0010] Fig. 1 is a schematic cross-sectional view of an electrophotographic member according to one embodiment of the present disclosure, and Fig. 2 is a schematic cross-sectional view of an image forming apparatus using the electrophotographic member according to one embodiment of the present disclosure.

[0011] In the present disclosure, 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. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined arbitrarily. 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. Note that when XX is a group, multiple XXs may be selected, and the same applies to YY and ZZ. In the present disclosure, the term "(meth)acrylic resin" refers to an acrylic resin and / or a methacrylic resin, the term "(meth)acrylic rubber" refers to an acrylic rubber and / or a methacrylic rubber, the term "(meth)acrylate" refers to an acrylate and / or a methacrylate, and the term "(meth)acrylic-modified silicone resin" refers to an acrylic-modified silicone resin and / or a methacrylic-modified silicone resin. In the present disclosure, the unit of surface resistance, Ω / □, refers to Ω / square.

[0012] Hereinafter, an electrophotographic member and an electrophotographic image forming apparatus according to an embodiment of the present disclosure will be described in detail with reference to the drawings. However, the scope of the present disclosure is not limited to this embodiment, and modifications within the scope of the present disclosure are also included in the present disclosure.

[0013] At least one aspect of the present disclosure relates to an electrophotographic member having a base layer and a surface layer on the base layer, wherein the surface layer contains at least one selected from the group consisting of a (meth)acrylic resin and a (meth)acrylic rubber, a plurality of resin particles are present on the outer surface of the surface layer, at least some of the plurality of resin particles are in direct contact with the outer surface of the surface layer, a portion of the outer surface of the electrophotographic member is made of the resin particles, and the outer surface of the electrophotographic member has irregularities formed by the resin particles, and the resin particles contain a (meth)acrylic-modified silicone resin.

[0014] As shown in FIG. 1 , an electrophotographic member according to one embodiment of the present disclosure has at least a base layer 101 and a surface layer 102 on the base layer. A plurality of resin particles 103 are present on the outer surface of the surface layer 102. At least some of the plurality of resin particles 103 are in direct contact with the outer surface of the surface layer 102. As a result, at least some of the plurality of resin particles 103 are provided on the outer surface of the surface layer 102. The outer surface of the surface layer 102 is the surface of the surface layer opposite the surface facing the base layer. A portion of the outer surface of the electrophotographic member is composed of the resin particles 103, and the outer surface of the electrophotographic member has irregularities formed by the resin particles. This results in excellent transferability. It is preferable that the resin particles 103 are independently arranged in the planar direction on the outer surface of the surface layer 102. It is also preferable that the resin particles 103 are almost completely absent from one another in the thickness direction or from being completely embedded in the surface layer 102, forming a substantially single layer. That is, it is preferable that the resin particles 103 on the outer surface of the surface layer 102 form a substantially single layer.

[0015] (Base Layer) The base layer 101 will now be described. The shape of the base layer 101 is not particularly limited, but may be, for example, a roll or belt, or a seamless cylindrical shape. An endless cylindrical shape is also preferred. The material of the base layer 101 is not particularly limited, but examples include the following: resins such as polyether ether ketone, polyethylene terephthalate, polybutylene naphthalate, polyester, polyimide, polyamide, polyamideimide, polyacetal, and polyphenylene sulfide. Among these, at least one selected from the group consisting of polyether ether ketone and polyimide is preferred, with polyimide being more preferred from the viewpoints of mechanical strength and heat resistance. The resin content in the base layer is not particularly limited, but may be 75 to 100% by mass, or 75 to 90% by mass.

[0016] The base layer 101 preferably contains a conductive powder such as metal powder, conductive oxide powder, or conductive carbon black. The inclusion of a conductive powder makes the base layer more conductive. Of these, conductive carbon black is preferred. The content of the conductive powder in the base layer is not particularly limited, but may be 10 to 25 mass %. From the viewpoint of obtaining excellent mechanical strength and conductivity, polyether ether ketone or polyimide containing carbon black is particularly preferred as the material for the base layer.

[0017] The thickness of the base layer 101 is not particularly limited and can be appropriately selected depending on the purpose. In consideration of use as an intermediate transfer member, the thickness is preferably 10 μm or more and 500 μm or less, and more preferably 30 μm or more and 200 μm or less. If the thickness is 10 μm or more, the mechanical strength is likely to be improved. Furthermore, if the thickness is 500 μm or less, suitable rigidity is likely to be obtained.

[0018] (Surface Layer) A surface layer 102 is formed on the base layer 101. That is, the surface layer 102 is formed on the outer peripheral surface of the base layer 101. The surface layer 102 is not particularly limited, but is preferably a resin layer, and more preferably an elastic layer. The elastic layer makes it easier for the toner on the outer surface of the electrophotographic member to follow the surface irregularities of the recording material, such as paper. The material of the elastic layer is not particularly limited, but it is preferable that the elastic layer contains a (meth)acrylic rubber from the viewpoint of achieving excellent transferability over a long period of time due to its high flexibility, high adhesion to resin particles, and high environmental stability. The content of the (meth)acrylic rubber in the elastic layer is not particularly limited, but may be 90 to 99% by mass.

[0019] The (meth)acrylic rubber may be any known rubber, and is not particularly limited. Examples of commercially available (meth)acrylic rubbers include the Nipol (trade name, manufactured by Zeon Corporation) series and the AREX (trade name, manufactured by JSR Corporation) series.

[0020] The (meth)acrylic rubber preferably has a structure represented by the following formula (1). In formula (1), R1 represents a methyl group or a hydrogen atom, and R2 represents an alkyl group having 1 to 18 carbon atoms (preferably 1 to 12, more preferably 1 to 9), or an alkyl group having 2 to 18 carbon atoms (preferably 2 to 12, more preferably 2 to 9) and an ether bond. The alkyl group represented by R2 may have any substituent.

[0021] The alkyl group having 2 to 18 carbon atoms and an ether bond is a functional group in which a methylene group in the alkyl group is substituted with oxygen. For example, R2 may have a structure represented by the following formula (1-1): -Ra-O-Rb (1-1) In formula (1-1), Ra represents an alkylene group having 1 to 17 carbon atoms (preferably 1 to 11, more preferably 1 to 8), Rb represents an alkyl group having 1 to 17 carbon atoms (preferably 1 to 11, more preferably 1 to 8), and the sum of the number of carbon atoms in Ra and the number of carbon atoms in Rb is 2 to 18 (preferably 2 to 12, more preferably 2 to 9).

[0022] The method for obtaining the elastic layer is not particularly limited, but examples thereof include a method of preparing a rubber composition containing a (meth)acrylic rubber, preparing a solution containing the rubber composition and a solvent, applying the solution to a base layer, and evaporating the solvent.

[0023] The (meth)acrylic rubber may contain a conductive agent for adjusting electrical properties, and, as necessary, additives such as a crosslinking accelerator, a crosslinking retarder, a crosslinking aid, a vulcanizing agent, a flame retardant, a flame retardant aid, an ultraviolet absorber, and a rust inhibitor. These may be used alone or in combination. The total content of the additives in the (meth)acrylic rubber is not particularly limited, but may be 0.1 to 5 mass %.

[0024] The elastic layer preferably contains a conductive agent. The conductive agent is not particularly limited, but examples thereof include an electronic conductive agent and an ionic conductive agent. The ionic conductive agent is not particularly limited, but potassium bis(trifluoromethanesulfonyl)imide is preferred. The content of the conductive agent in the elastic layer is not particularly limited, but may be 0.1 to 1 mass %.

[0025] The electrical resistivity of the elastic layer is not particularly limited. For example, the surface resistivity of the elastic layer is 1×10 ８ ~1 x 10１４ It is preferable that the volume resistivity of the elastic layer is 1×10 ６ ~1 x 10 １３ It is preferably Ω·cm. For example, when the elastic layer contains a conductive agent, the electrical resistivity of the elastic layer can be adjusted by the amount of the conductive agent.

[0026] The thickness of the elastic layer is not particularly limited, but is preferably 100 μm to 2 mm, more preferably 400 μm to 1 mm. If the thickness is less than 100 μm, the ability to follow the unevenness of the paper may decrease, and transferability may decrease. On the other hand, if the thickness is greater than 2 mm, cracks may easily occur due to bending at the roller portion for tensioning the electrophotographic member, and image quality may decrease.

[0027] From the viewpoint of achieving both conformability to paper irregularities and toner releasability and easily maintaining high image quality, the elastic deformation power ηIT of the electrophotographic member is preferably 60% to 90%. Specifically, when a Vickers indenter is placed against the outer surface of the elastic layer and a nanoindentation test of the elastic layer according to ISO 14577 is performed with a test load of 120 μN to obtain a load-displacement curve, the elastic deformation power ηIT calculated from the load-displacement curve is preferably 60% to 90%. A test load of 120 μN may correspond to the load exerted when toner is pressed into the electrophotographic member in an electrophotographic image forming apparatus. Furthermore, an elastic deformation power of an electrophotographic member above a certain level indicates that the member maintains its elasticity and easily returns to its original shape when unloaded. With an elastic deformation power within the above range, the deformed surface layer returns to its original state without permanent deformation, thereby reducing the contact area between the toner and the surface layer. This is believed to improve toner releasability and transferability. For example, when the elastic layer contains an additive, the elastic deformation power η IT can be adjusted by changing the content of the additive, such as a vulcanizing agent.

[0028] As described above, the surface layer is preferably a resin layer. The resin layer is a layer containing a resin. The resin is not particularly limited, but a (meth)acrylic resin is preferred. The content of the resin in the resin layer is not particularly limited, but may be 70 to 100% by mass, or 70 to 90% by mass.

[0029] The method for obtaining the resin layer is not particularly limited, and examples thereof include a method of preparing a solution containing a (meth)acrylic resin and a solvent, applying the solution to a base layer, and evaporating the solvent. Alternatively, a resin layer can be formed by preparing a solution containing a polymerizable monomer for forming a (meth)acrylic resin and a solvent, applying the solution to a base layer, evaporating the solvent, and polymerizing the polymerizable monomer on the base layer.

[0030] The polymerizable monomer is not particularly limited, but examples thereof include (meth)acrylic acid and (meth)acrylate, among which (meth)acrylate is preferred. The (meth)acrylate is not particularly limited, but examples thereof include monofunctional (meth)acrylates such as hexyl (meth)acrylate, cyclohexyl (meth)acrylate, and benzyl (meth)acrylate; and polyfunctional (meth)acrylates having two or more functional groups such as 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. Among these, it is preferable to use a polyfunctional (meth)acrylate having three or more functional groups such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate, and it is preferable to use at least one polyfunctional (meth)acrylate selected from the group consisting of trimethylolpropane tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. By using a polyfunctional (meth)acrylate, the strength of the resin layer is likely to be improved.

[0031] A polymerization initiator may be used as needed to carry out the polymerization. Examples of the polymerization initiator include radical polymerization initiators such as alkylphenones and acylphosphine oxides, cationic polymerization initiators such as aromatic sulfonium salts, and anionic polymerization initiators such as nifedipine.

[0032] The structure of the (meth)acrylic resin is not particularly limited, but it is preferable that the (meth)acrylic resin has a structure represented by the following formula (1'). In formula (1'), R7 represents a methyl group or a hydrogen atom, and R8 represents an alkyl group having 1 to 18 carbon atoms (preferably 1 to 12, more preferably 1 to 9), or an alkyl group having 2 to 18 carbon atoms (preferably 2 to 12, more preferably 2 to 9) and an ether bond. The alkyl group represented by R8 may have any substituent.

[0033] The alkyl group having 2 to 18 carbon atoms and an ether bond is a functional group in which a methylene group in the alkyl group is substituted with oxygen. That is, R8 may have the structure represented by the above formula (1-1), similar to the above R2.

[0034] The resin layer may also contain other known additives such as a conductive agent, an antioxidant, a leveling agent, a crosslinking agent, and a flame retardant. The total content of the additives in the resin layer is not particularly limited, but may be 1 to 30 mass %.

[0035] The thickness of the resin layer is not particularly limited, but is preferably 1 to 20 μm, and more preferably 2 to 10 μm. If the thickness is less than 1 μm, the effect of the resin layer is likely to be reduced due to wear and tear during long-term use. Furthermore, if the thickness is greater than 20 μm, cracks are likely to occur due to bending at the roller portion for stretching the electrophotographic member, which may result in a decrease in image quality. The thickness of the resin layer can be adjusted by adjusting the conditions for forming the resin layer, such as the solid content concentration and film formation speed.

[0036] (Resin Particles) Next, the resin particles 103 will be described. The resin particles 103 contain a (meth)acrylic-modified silicone resin. By containing the (meth)acrylic-modified silicone resin, the electrophotographic member has excellent adhesion to the (meth)acrylic rubber and (meth)acrylic resin that may be contained in the surface layer, as well as excellent toner releasability. The reason for this excellent adhesion is thought to be that the (meth)acrylic-modified silicone resin has a structure similar to the structure contained in the (meth)acrylic rubber and the structure contained in the (meth)acrylic resin, and is therefore compatible with the (meth)acrylic rubber and the (meth)acrylic resin. The reason for this excellent releasability is thought to be that the (meth)acrylic-modified silicone resin has a silicone skeleton. The content of the (meth)acrylic-modified silicone resin in the resin particles is not particularly limited, but may be 95 to 100% by mass. Furthermore, the resin particles are preferably (meth)acrylic-modified silicone resin particles.

[0037] Although the (meth)acrylic-modified silicone resin is not particularly limited, it is preferable that the (meth)acrylic-modified silicone resin has a structure represented by the following formula (2). By having the structure represented by the following formula (2), the toner releasability is more likely to be excellent. Furthermore, it is preferable that the (meth)acrylic-modified silicone resin has a structure represented by the following formula (3). By having the structure represented by the following formula (3), the adhesion to the (meth)acrylic rubber and (meth)acrylic resin that may be contained in the surface layer is more likely to be excellent. -Si(R3)(R4)-O- (2) In formula (2), R3 and R4 each independently represent an alkyl group having 1 to 3 carbon atoms or a hydroxyl group. In formula (3), R5 represents a hydrogen atom or a methyl group, and R6 represents an alkyl group having 1 to 6 carbon atoms. R6 may be linear, branched, or cyclic.

[0038] The structure contained in the (meth)acrylic-modified silicone resin particles is measured using pyrolysis GC-MS and silicon NMR. Specific measurement methods will be described later. The (meth)acrylic-modified silicone resin more preferably has the structure represented by formula (2) above in the main chain. Furthermore, the (meth)acrylic-modified silicone resin more preferably has the structure represented by formula (3) above in the side chain.

[0039] The proportion of the structure represented by the above formula (2) in the (meth)acrylic-modified silicone resin is preferably 60 to 80 mol %. When the proportion of the structure represented by the above formula (2) is within this range, the toner tends to have even better releasability. The proportion of the structure represented by the above formula (2) is measured using pyrolysis GC-MS and silicon NMR.

[0040] The proportion of the structure represented by formula (3) in the (meth)acrylic-modified silicone resin is preferably 20 to 40 mol %. When the proportion of the structure represented by formula (3) is within the above range, the compatibility between the (meth)acrylic portion of the (meth)acrylic-modified silicone resin and the (meth)acrylic rubber and (meth)acrylic resin that may be contained in the surface layer 102 in contact with the resin particles is improved, making it easier to suppress detachment of the resin particles. Furthermore, the silicone main chain contained in the silicone resin tends to improve the toner's releasability. The proportion of the structure represented by formula (3) is measured using pyrolysis GC-MS and silicon NMR. Specific measurement methods are described below. Known (meth)acrylic-modified silicone resins can be used and are not particularly limited. Commercially available products include, for example, Chaline (registered trademark) R-170S and R-175S (manufactured by Nissin Chemical Industry Co., Ltd.).

[0041] The particle size of the resin particles is not particularly limited, but the number-average particle size is preferably 0.1 to 5 μm, and more preferably 0.5 to 2 μm. If the number-average particle size exceeds the above range, the gaps between the resin particles tend to become large. As a result, the toner release properties may decrease and cleaning problems may occur. Furthermore, if the number-average particle size is smaller than the above range, aggregation may occur between the resin particles, making it difficult to apply the resin particles to the surface layer. If the particle size of the resin particles varies, the resin particles may be classified using a sieve or the like as necessary to select and use the desired particles.

[0042] When the outer surface of the electrophotographic member is observed with a scanning electron microscope (SEM), and the length in the longitudinal direction perpendicular to the circumferential direction of the electrophotographic member is W, the number of resin particles present in a square observation region of 5 μm length × 5 μm width at any position in a central region of W / 3 from the center of the longitudinal direction of the electrophotographic member toward both ends in the longitudinal direction is preferably 1 to 700, more preferably 1 to 350, even more preferably 1 to 100, particularly preferably 1 to 50, and especially preferably 1 to 30. Here, the circumferential direction of the electrophotographic member includes, for example, the circumferential direction of the electrophotographic member when the electrophotographic member is an electrophotographic belt having an endless shape, and the circumferential direction of the electrophotographic member when the electrophotographic member is cylindrical.

[0043] The presence of zero particles in the observation area indicates that there are large gaps between the resin particles. As a result, toner release properties may be reduced or cleaning problems may occur. On the other hand, the presence of more than 700 resin particles in the observation area indicates a state in which aggregation between the resin particles is likely to occur. In other words, it may be difficult to apply a paint containing resin particles to the surface of the surface layer 102. The number of resin particles present in the observation area can be adjusted by changing the amount of resin particles applied.

[0044] The observation conditions for the SEM are as follows: SEM: Product name S-4700, manufactured by Hitachi Observation conditions: 10K magnification Acceleration voltage: 2 kV

[0045] The outer surface of an electrophotographic member is observed with a scanning electron microscope (SEM). The length of the electrophotographic member in the longitudinal direction perpendicular to the circumferential direction is W. Based on the area of ​​a square observation region measuring 5 μm long and 5 μm wide at any position in the central region of W / 3 from the center of the electrophotographic member to both ends in the longitudinal direction, the proportion of the area occupied by resin particles is preferably 50 to 90 area%, more preferably 50 to 80 area%, and even more preferably 50 to 70 area%. Within the above range, good toner releasability is easily achieved. The proportion of the area occupied by resin particles can be adjusted by changing the amount of resin particles applied or the particle diameter of the resin particles. The proportion of the area occupied by resin particles is determined by observing the outer surface of the electrophotographic member at multiple locations in the circumferential direction and calculating the arithmetic average of the obtained area proportions. Specifically, the proportion is measured as follows. That is, the observed image is binarized (e.g., Otsu's method) using image processing software (e.g., ImageJ), the particle portions are extracted, and the total area of ​​the particle portions is calculated. The total area of ​​the particle portions is divided by the area of ​​the entire observed image, and the result is multiplied by 100 to calculate the proportion of the area occupied by the resin particles.

[0046] (Electrophotographic image forming apparatus) The electrophotographic image forming apparatus of the present disclosure is an electrophotographic image forming apparatus comprising: an image forming unit including an image carrier, a charging means, an image exposure means, and a developing means; an intermediate transfer body; a primary transfer member that primarily transfers a toner image formed on the image carrier onto the intermediate transfer body; and a secondary transfer member that secondarily transfers the toner image on the intermediate transfer body using a recording material, wherein the developing means is provided with a toner storage section that stores toner, and the intermediate transfer body is the electrophotographic member of the present disclosure.

[0047] An example of an electrophotographic image forming apparatus using the electrophotographic member of the present disclosure will be described with reference to Fig. 2. It should be noted that the present disclosure is not limited to the following description.

[0048] The electrophotographic image forming apparatus 100 in FIG. 2 is a color electrophotographic image forming apparatus (color laser printer). This electrophotographic image forming apparatus is equipped with an electrophotographic belt (electrophotographic member) 7, which serves as an intermediate transfer member. That is, the intermediate transfer member is preferably the electrophotographic member of the present disclosure. The electrophotographic member is preferably an endless electrophotographic belt. 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 electrophotographic belt 7 in the moving direction of the belt. In FIG. 2, 1Y, 1M, 1C, and 1K respectively represent electrophotographic photosensitive members, and 2Y, 2M, 2C, and 2K respectively represent charging rollers. Furthermore, 3Y, 3M, 3C, and 3K respectively represent laser exposure devices, 4Y, 4M, 4C, and 4K respectively represent developing devices, and 5Y, 5M, 5C, and 5K respectively represent primary transfer rollers. Since the basic configuration of each image forming unit is the same, the details of the image forming units will be described only for the yellow image forming unit Py.

[0049] The yellow image forming unit Py has a drum-shaped electrophotographic photosensitive member 1Y (hereinafter also referred to as "photosensitive drum" or "first image bearing member") as an image bearing member. 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. The yellow image forming unit Py also has 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.

[0050] A laser exposure device 3Y serving as an image exposure unit 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. The electrostatic latent image formed on the photosensitive drum 1Y is developed with toner, which serves as a developer, by a developing device 4Y serving as a developing unit. That is, the developing unit includes a toner container that contains toner. The developing device 4Y includes a developing roller 4Ya, which serves as a developer carrier, and a regulating blade 4Yb, which serves as a developer amount regulating member, and contains yellow toner, which serves 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 at a speed different from that of the photosensitive drum 1Y in the forward direction. 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 development bias to the developing roller 4Ya. As a result, a visible image (yellow toner image) is formed on the photosensitive drum 1Y.

[0051] The electrophotographic belt 7 is stretched over a drive roller 71, a tension roller 72, and a driven roller 73, and is moved (rotationally driven) in contact with the photosensitive drum 1Y in the direction of the arrow in the figure. The yellow toner image formed on the photosensitive drum (first image carrier) that has reached the primary transfer portion Ty is primarily transferred onto the electrophotographic belt 7 by a primary transfer member (primary transfer roller 5Y) disposed opposite the photosensitive drum 1Y via the electrophotographic belt 7. That is, the electrophotographic image forming apparatus includes a primary transfer member that primarily transfers the toner image formed on the image carrier onto the intermediate transfer member. Similarly, the above-described image forming operation is performed in each of the magenta (M), cyan (C), and black (K) units Pm, Pc, and Pk as the electrophotographic belt 7 moves, and toner images of four colors, yellow (Y), magenta (M), cyan (C), and black (K), are layered on the electrophotographic belt 7. The four-color toner images are transported along the movement of the electrophotographic belt 7, and at the secondary transfer portion T', a secondary transfer member (secondary transfer roller 8) transfers the four-color toner images collectively onto a recording material S (hereinafter also referred to as a "second image carrier") that is transported at a predetermined timing. That is, the electrophotographic image forming apparatus is provided with a secondary transfer member that performs a second transfer of the toner image on the intermediate transfer member onto the recording material. In such a secondary transfer, a transfer voltage of several kV is usually applied to ensure a sufficient transfer rate.

[0052] The recording material S is supplied to a conveying path by a pickup roller 13 from a cassette 12 in which the recording material S is stored. The recording 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 electrophotographic belt 7 by a pair of conveying rollers 14 and a pair of registration rollers 15. The toner image transferred to the recording 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 recording material S by applying heat and pressure. The recording material S is then discharged to the outside of the apparatus by a pair of conveying rollers 16, a pair of discharge rollers 17, etc.

[0053] A cleaning unit for the electrophotographic belt 7 is disposed downstream of the secondary transfer portion T' in the driving direction of the electrophotographic belt 7, and removes the residual toner remaining on the electrophotographic belt 7 without being transferred to the recording material S at the secondary transfer portion T'.

[0054] As described above, the process of electrically transferring a toner image from the photoreceptor to the electrophotographic belt and from the electrophotographic belt to the recording material is repeated. Furthermore, by repeatedly recording on a large number of recording materials, the electrical transfer process is further repeated.

[0055] (Toner and Developer) The toner used in the electrophotographic image forming apparatus is not particularly limited, but is preferably a toner containing toner particles, and the toner particles contain a polyester resin having a polyethylene terephthalate segment. The toner will be described below.

[0056] <Polyester Resin Having Polyethylene Terephthalate Segment> The polyester resin has a polyethylene terephthalate segment and can be obtained by selecting and combining suitable monomers from among divalent or higher alcohol monomers, divalent or higher carboxylic acids, divalent or higher carboxylic acid anhydrides, divalent or higher carboxylic acid esters, and the like, and synthesizing the resulting polyester resin using a known method.

[0057] <Polyethylene terephthalate segment> The polyethylene terephthalate segment is a structural unit of polyethylene terephthalate, １０ H ８ O ４ The polyethylene terephthalate segment can be obtained by producing a polyester resin according to a known method through a condensation reaction or transesterification reaction between ethylene glycol and terephthalic acid, dimethyl terephthalate, or the like. Alternatively, the polyethylene terephthalate segment can be obtained by synthesizing a polyester resin using recovered polyethylene terephthalate resin as a monomer.

[0058] Polyethylene terephthalate resin is used in various products such as containers and films, and from the viewpoint of environmental protection, it is preferable to recover and reuse it. That is, recovered polyethylene terephthalate resin refers to recycled polyethylene terephthalate resin. The type of recovered polyethylene terephthalate resin is not particularly limited, but it is preferable that it does not contain impurities that may affect toner properties or reactions during the manufacturing process. Furthermore, it is more preferable that it has an appropriate purity.

[0059] <Dihydric or Higher Alcohol Monomer Component> The dihydric or higher alcohol monomer component is not particularly limited, but examples thereof include alkylene oxide adducts of bisphenol A such as polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(3.3)-2,2-bis(4-hydroxyphenyl)propane, polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(2.0)-polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, and polyoxypropylene(6)-2,2-bis(4-hydroxyphenyl)propane; ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, neopentyl glycol, polyethylene glycol, and polypropylene glycol. These may be used alone or in combination. Among these, alkylene oxide adducts of bisphenol A are preferred.

[0060] <Acid Monomer Component> The acid monomer components such as divalent or higher carboxylic acids, divalent or higher carboxylic acid anhydrides, and divalent or higher carboxylic acid esters are not particularly limited, but include aromatic dicarboxylic acids or their anhydrides such as phthalic acid, isophthalic acid, and terephthalic acid; alkyl dicarboxylic acids or their anhydrides such as oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, fumaric acid, citraconic acid, and itaconic acid. These can be used alone or in combination. Among them, fumaric acid is preferred.

[0061] <Method for producing polyester resin having polyethylene terephthalate segment> A polyester resin having polyethylene terephthalate segment can be produced according to a conventional polyester synthesis method, except that the polyethylene terephthalate segment is obtained by the method described above. For example, a desired polyester resin can be obtained by esterifying a carboxylic acid monomer and an alcohol monomer or by transesterifying the carboxylic acid monomer and then polycondensing the resulting mixture under reduced pressure or by introducing nitrogen gas according to a known method.

[0062] <Release Agent> The toner particles may contain a release agent. The release agent preferably contains a wax. Examples of waxes include polyolefin waxes such as polyethylene wax, polypropylene wax, and polypropylene copolymer wax; petroleum waxes such as microcrystalline wax and paraffin wax; hydrocarbon waxes such as Fischer-Tropsch wax; natural waxes such as carnauba wax, rice wax, and candelilla wax; and montan wax. These waxes may be derivatives. These may be used alone or in combination. The content of the release agent in the toner particles is not particularly limited, but may be 1 to 5% by mass.

[0063] <Colorant> The toner particles may contain a colorant. Examples of colorants include known organic pigments, oil-based dyes, and magnetic materials. Examples of colorants include carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment red 122, pigment green B, rhodamine B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazo yellow, benzidine yellow, monoazo dyes and pigments, and disazo dyes and pigments. The content of the colorant in the toner particles is not particularly limited, but may be 2 to 8% by mass.

[0064] <Charge Control Agent> The toner particles may contain a charge control agent as necessary. Known charge control agents can be used, including positive charge control agents and negative charge control agents. Positive charge control agents include quaternary ammonium salt compounds, triphenylmethane compounds, imidazole compounds, and nigrosine dyes. Negative charge control agents include benzilic acid metal compounds, salicylic acid metal compounds, copper phthalocyanine dyes, and quaternary ammonium salt compounds. Of these, negative charge control agents are preferred. The content of the charge control agent in the toner particles is not particularly limited, but may be 0.1 to 2% by mass.

[0065] Although the toner can be used as a one-component developer, it is preferable to use the toner as a two-component developer by mixing it with a magnetic carrier in order to further improve dot reproducibility and to provide stable images over a long period of time. As the magnetic carrier, for example, commonly known particles such as metal particles of iron, cobalt, or nickel, or magnetic materials such as ferrite can be used.

[0066] The present disclosure will be specifically described below using examples. However, the present disclosure is not limited to the following examples. Note that the number of parts in the following formulations is always by mass unless otherwise specified.

[0067] Example 1 (Preparation of Electrophotographic Belt) (Formation of Base Layer) Conductive carbon black (product name: Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to an N-methyl-2-pyrrolidone solution of polyamic acid, a polyimide precursor (product name: U Varnish A, manufactured by Ube Industries, Ltd.). The conductive carbon black was added and mixed so that the amount of conductive carbon black was 19% by mass relative to the total mass of the polyamic acid and the conductive carbon black. The resulting mixture was applied to the outer surface of a cylindrical support made of stainless steel (SUS304) whose surface had been subjected to a blast treatment. The cylindrical support was then heated in a heating furnace at a temperature of 220°C for 30 minutes, followed by heating at a temperature of 350°C for 30 minutes. This polymerized the polyimide precursor applied to the outer surface of the cylindrical support, forming a polyimide film. After cooling, the polyimide film was removed from the cylindrical support, yielding an endless belt-shaped base layer with a thickness of 70 μm.

[0068] The outer peripheral surface of the obtained base layer was then irradiated with excimer UV to perform a hydrophilic treatment, after which a primer liquid (product name: DY39-051A / B, manufactured by Dow Toray Industries, Inc.) was applied to the outer peripheral surface of the base layer, and the base layer was placed in a heating furnace and heated at 160°C for 10 minutes.

[0069] (Formation of Surface Layer) After the base layer was sufficiently cooled, an elastic layer was formed on the base layer as a surface layer. Specifically, the elastic layer was formed by the following procedure. The constituent materials shown below were kneaded using a twin-screw kneader (trade name: PCM30, manufactured by Ikegai Corporation) to obtain pellets.

[0070] Acrylic rubber (trade name: Nipol AR12, manufactured by Zeon Corporation) 100 parts by mass (6-aminohexyl)carbamic acid (trade name: Diak No. 1, manufactured by Chemours) 0.6 parts by mass 1,3-di-o-tolylguanidine (trade name: Noccela DT, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) 1 part by mass Stearic acid (trade name: Beads Stearic Acid, manufactured by NOF Corporation) 1 part by mass Potassium bis(trifluoromethanesulfonyl)imide potassium (trade name: EF-N112, manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.) 0.2 parts by mass

[0071] The obtained pellets were dissolved in methyl isobutyl ketone (MIBK) as a solvent to prepare a coating liquid for the elastic layer. The previously prepared base layer was attached to a cylindrical core, and a ring nozzle for discharging rubber was attached coaxially with the core. The coating liquid for the elastic layer was supplied to the ring nozzle using a liquid feed pump and discharged through a slit, thereby applying the coating liquid for the elastic layer onto the base layer. The coating amount was set so that the final film thickness would be 500 μm.

[0072] (Providing Resin Particles on the Outer Surface of the Surface Layer) Next, resin particles were provided on the outer surface of the applied coating liquid. The resin particles used were classified acrylic-modified silicone resin particles (Resin Particles A, product name: Chaline R-170S, manufactured by Nissin Chemical Industry Co., Ltd.) (number average particle diameter: 1 μm). Specifically, the resin particles were provided using the following procedure. The acrylic-modified silicone resin particles were evenly spread on the surface of the coating liquid applied to the previously prepared base layer, and excess particles were removed by smoothing with a pressing member. The base layer containing the coating liquid and the particles on the surface of the coating liquid was then placed over a cylindrical support, heated to 160°C in a heating furnace at a heating rate of 5°C / min, and maintained there for 60 minutes. The resulting product was then cooled to room temperature and demolded to obtain an electrophotographic belt. At least a portion of the resin particles were in direct contact with the outer surface of the surface layer, and a portion of the outer surface of the electrophotographic belt was composed of the resin particles.

[0073] When the surface of the produced electrophotographic belt was observed with a scanning electron microscope (SEM) using the method described above, the number of resin particles present in a 5 μm × 5 μm square observation area was found to be 21. Furthermore, the proportion of the area occupied by the resin particles based on the area of ​​the square observation area was 65 area %.

[0074] The structures of the (meth)acrylic unit and silicone unit of the (meth)acrylic-modified silicone resin particles used were identified by pyrolysis GC-MS (manufactured by Agilent). The pyrolysis GC-MS conditions were as follows: Apparatus: 6890N (manufactured by Agilent Technologies); Accessory: Multi-Shot Pyrolyzer PY3030D (manufactured by Frontier Labs); Pyrolysis temperature: 600°C. Furthermore, the (meth)acrylic-modified silicone resin particles were dissolved in a heavy solvent (heavy chloroform) and subjected to silicon NMR measurement to measure the molar ratio of the structure bonded to silicon atoms. Specifically, the proportion of silicon moieties bonded to (meth)acrylic groups relative to the total silicon contained in the (meth)acrylic-modified silicone resin particles was calculated, and this was taken as the proportion of the structure represented by formula (3) above. The proportion of the structure represented by formula (3) above in the particles according to this example was 30 mol%.

[0075] (Developer Preparation) In this example, the following developer was used. [Production of Resin 1] 100 parts of a propylene oxide adduct of bisphenol A (average number of moles added: 2.2 moles), 21 parts of recovered polyethylene terephthalate (diethylene glycol content = 1.3% by mass), and 0.08 parts of dibutyltin oxide were added to a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet tube under a nitrogen atmosphere. The reaction vessel was heated to 230°C while stirring at 200 rpm, and the reaction was carried out for 7 hours. Subsequently, the reaction mixture was cooled to 180°C, and 30 parts of fumaric acid and 0.08 parts of hydroquinone were added, followed by heating to 210°C over 4 hours. The pressure was then reduced to 8 kPa, and the reaction was continued until the softening point reached 103°C, yielding Resin 1.

[0076] [Production of Resin 2] A reflux condenser, a stirrer, a thermometer, and a reaction vessel equipped with a nitrogen inlet tube were charged with 100 parts of a propylene oxide adduct of bisphenol A (average number of moles added: 2.2 moles), 40 parts of an ethylene oxide adduct of bisphenol A (average number of moles added: 2.2 moles), 13 parts of dodecenyl succinic anhydride, 37 parts of terephthalic acid, 12 parts of trimellitic anhydride, and 0.5 parts of dibutyltin oxide. The reaction vessel was heated to 235 ° C. and reacted for 4 hours while stirring at 200 rpm. The pressure was then reduced to 8 kPa and the reaction was continued until the softening point reached 146 ° C., yielding Resin 2.

[0077] [Production of Toner Particles 1] Resin 1: 70 parts Resin 2: 30 parts Colorant: ECB-301 (manufactured by Dainichiseika Color & Chemicals Co., Ltd., C.I. Pigment Blue 15:3): 5 parts Charge control agent: LR-147 (manufactured by Nippon Carlit Co., Ltd.): 1 part Release agent: NP-105 (manufactured by Mitsui Chemicals, Inc., melting point: 140°C): 4 parts The above materials were mixed in a Henschel mixer (FM-75 model, manufactured by Nippon Coke & Engineering Co., Ltd.) at a rotation speed of 20 s －１ The mixture was mixed for 5 minutes at a rotation time of 120°C and discharged at a temperature of 135°C using a twin-screw kneader (PCM-30, manufactured by Ikegai Corporation) set at a temperature of 120°C and a screw rotation speed of 200 rpm. The resulting kneaded mixture was cooled at a cooling rate of 15°C / min and roughly pulverized to 1 mm or less using a hammer mill to obtain a coarsely pulverized product. The resulting coarsely pulverized product was finely pulverized using a mechanical pulverizer (T-250, manufactured by Freund Turbo Corporation). Further, classification was performed using a Faculty F-300 (manufactured by Hosokawa Micron Corporation) to obtain toner particles 1. The operating conditions for classification were a classifying rotor rotation speed of 130 s －１ , the distributed rotor rotation speed is 120 s －１ It was decided.

[0078] [Production of Toner 1] The following materials were mixed in a Henschel mixer FM-10C (manufactured by Mitsui Miike Chemical Engineering Co., Ltd.) at a rotation speed of 30 s. －１The mixture was mixed at 100 parts by rotation for 10 minutes to obtain toner 1. Toner particles 1 100 parts External additive 1 Aerosil R-972 (manufactured by Nippon Aerosil Co., Ltd., average particle size 16 nm) 1.0 part External additive 2 SI-Y (manufactured by Nippon Aerosil Co., Ltd., average particle size 40 nm) 1.0 part

[0079] (Magnetic Carrier Manufacturing Example) Number average particle size: 0.30 μm, magnetization strength under a magnetic field of 1000 / 4π (kA / m): 65 Am ２ / kg) magnetite 1 Number average particle size 0.50 μm, (magnetization strength 65 Am under a magnetic field of 1000 / 4π (kA / m) ２ / kg) magnetite 2 4.0 parts of a silane compound (3-(2-aminoethylaminopropyl)trimethoxysilane) was added to 100 parts of each of the above materials, and the mixture was mixed and stirred at high speed at 100°C or higher in a container to treat each of the fine particles.

[0080] Phenol: 10% by mass; Formaldehyde solution: 6% by mass (40% by mass of formaldehyde, 10% by mass of methanol, 50% by mass of water); Magnetite 1 treated with the above silane compound: 58% by mass; Magnetite 2 treated with the above silane compound: 26% by mass. 100 parts of the above materials, 5 parts of a 28% by mass aqueous ammonia solution, and 20 parts of water were placed in a flask and heated to 85°C over 30 minutes while stirring and mixing. After heating, the mixture was held for 3 hours to allow a polymerization reaction and harden the resulting phenolic resin. The hardened phenolic resin was then cooled to 30°C, and additional water was added. The supernatant was then removed, and the precipitate was washed with water and air-dried. The air-dried product was then dried under reduced pressure (5 mmHg or less) at 60°C to obtain spherical magnetic carrier 1 with dispersed magnetic material. The volume-based 50% particle size (D50) of magnetic carrier 1 was 34 μm.

[0081] [Production Example of Developer 1] The following materials were mixed in a V-type mixer (V-20, manufactured by Seishin Enterprises) to obtain Developer 1: Toner 1 8 parts Magnetic carrier 1 92 parts

[0082] In Example 2, an electrophotographic belt was produced in the same manner as in Example 1, except that the surface layer in Example 1 was changed to a resin layer (acrylic resin). Specifically, the resin layer was formed in the following manner.

[0083] (Preparation of Resin Layer) The following materials were stirred with a homogenizer to prepare an intermediate (H): 26.9 parts by mass of methyl ethyl ketone (manufactured by Kishida Chemical Co., Ltd.), 26.9 parts by mass of butyl acetate (manufactured by Kishida Chemical Co., Ltd.), 42.0 parts by mass of Aronix M405 (manufactured by Toagosei Co., Ltd.), 2.9 parts by mass of Irgacure 184 (manufactured by BASF), and 1.1 parts by mass of Irgacure 369 (manufactured by BASF).

[0084] A conductive agent was added to the intermediate (H) in the following proportions, and the mixture was stirred using a mix rotor to prepare a coating material (I): 79 parts by mass of intermediate (H), 3 parts by mass of Celnax CX-Z410K (Nissan Chemical Industries, Ltd.), 6 parts by mass of Celnax CX-Z210IP (Nissan Chemical Industries, Ltd.), and 12 parts by mass of isopropyl alcohol (Kishida Chemical Industries, Ltd.).

[0085] The outer peripheral surface of the base layer prepared in the same manner as in Example 1 was treated with a corona treatment device (manufactured by Kasuga Electric Co., Ltd.) at a discharge rate of 100 W·min / m ２ Corona treatment was performed under the conditions (adhesion-enhancing treatment). Thereafter, paint (I) was spray-coated onto the outer peripheral surface of the base layer. Then, resin particles A similar to those in Example 1 were applied to the outer surface of the spray-coated paint (I) in the same manner as in Example 1. The solvent was then evaporated in a drying oven at 70°C for 1 minute, and a curing reaction was carried out by the effect of UV. The thickness of the resulting resin layer was 8 μm.

[0086] When the surface of the produced electrophotographic belt was observed by a scanning electron microscope (SEM) using the method described above, the number of resin particles present in a square observation area of ​​5 μm × 5 μm was 20. Furthermore, the proportion of the area occupied by the resin particles based on the area of ​​the square observation area was 63 area %.

[0087] In Example 3, an electrophotographic belt was produced in the same manner as in Example 2, except that TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd.) was used instead of Aronix M405 in Example 2. The thickness of the resulting resin layer was 8 μm.

[0088] When the surface of the produced electrophotographic belt was observed by a scanning electron microscope (SEM) using the method described above, the number of resin particles present in a square observation area of ​​5 μm × 5 μm was 20. Furthermore, the proportion of the area occupied by the resin particles based on the area of ​​the square observation area was 63 area %.

[0089] [Comparative Example 1] In Comparative Example 1, an electrophotographic belt was produced in the same manner as in Example 1, except that the resin particles A in Example 1 were changed to the following resin particles B: Acrylic resin particles (resin particles B, trade name: TECHPOLYMER SSX-101, manufactured by Sekisui Plastics Co., Ltd.)

[0090] Comparative Example 2 In Comparative Example 1, an electrophotographic belt was produced in the same manner as in Example 1, except that the resin particles A in Example 1 were changed to the following resin particles C: Silicone resin particles (product name: Tospearl 120, manufactured by Momentive Performance Materials, Inc.)

[0091] (Calculation of Elastic Deformation Power ηIT) Using the produced electrophotographic belt, the nanoindentation test of the elastic layer based on ISO 14577 described above was carried out, and the elastic deformation power ηIT was calculated from the measurement results of the load-displacement curve.

[0092] (Evaluation of Image Density Uniformity) The evaluation of image density uniformity was carried out by installing the electrophotographic belt as an intermediate transfer belt in a full-color electrophotographic forming apparatus (product name: ImagePRESS C800, manufactured by Canon Inc.). The image density uniformity was evaluated by printing the image on an A3-sized embossed paper (product name: Lezac 66 250 g / m ２Secondary solid color images of cyan and magenta were formed on a sheet of paper (manufactured by Tokushu Tokai Seishi Co., Ltd.) and evaluated according to the following criteria: Rank A: No image unevenness was observed and good Rank B: Slight image unevenness was observed in some of the embossed paper recesses Rank C: Clear image unevenness was observed in less than 50% of the embossed paper recesses Rank D: Clear image unevenness was observed in more than 50% of the embossed paper recesses

[0093] (Evaluation of Image Density Uniformity After Durability) Using the above electrophotographic forming apparatus, images were continuously output on 100,000 sheets (test chart) of A3-size plain paper (product name: CS068, manufactured by Canon Inc.) in an environment of a temperature of 25° C. and a relative humidity of 55%. Thereafter, images were output on 100,000 sheets (test chart) of A3-size embossed paper (product name: Lezac 66 250 g / m ２ Solid images of secondary colors of cyan and magenta were formed on the entire surface of a sheet of paper (manufactured by Tokushu Tokai Seishi Co., Ltd.), and evaluated according to the same criteria as in the evaluation of image density uniformity described above.

[0094] (Evaluation Results) The evaluation results of the electrophotographic belts produced in Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1. In Example 1, both the image density uniformity and the image density uniformity after the durability test were good. In Examples 2 and 3, slight image unevenness was observed in the image density uniformity, but it was within the acceptable range, and the results were similar after the durability test. Note that, since Examples 2 and 3 did not have an elastic layer, measurement of the elastic deformation power was not performed. In Comparative Example 1, clear image unevenness was observed. This is thought to be because the resin particles were acrylic resin particles, which had lower toner release properties and lower transferability compared to acrylic-modified silicone resin particles. On the other hand, no deterioration in image quality was observed after the durability test. This is thought to be due to the high compatibility between the acrylic resin particles and the acrylic rubber. In Comparative Example 2, the image density uniformity was good, but the image density uniformity after the durability test deteriorated. When the electrophotographic belt surface was observed with a scanning electron microscope (SEM), detachment of resin particles was observed. It is believed that the wood particles are silicone resin particles and therefore have poor compatibility with the acrylic rubber, causing them to fall off during paper feeding.

[0095] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the present disclosure. Therefore, the following claims are appended to clarify the scope of the present disclosure. This application claims priority based on Japanese Patent Application No. 2024-065216 filed on April 15, 2024, and Japanese Patent Application No. 2025-043299 filed on March 18, 2025, the entire contents of which are incorporated herein by reference.

[0096] 1 Electrophotographic photosensitive member (photosensitive drum), 2 Charging roller, 3 Laser exposure device, 4 Developing device, 5 Primary transfer roller, 7 Electrophotographic belt, 8 Secondary transfer roller, 9 Fixing device, 101 Base layer, 102 Surface layer, 103 Resin particles

Claims

1. An electrophotographic member having a base layer and a surface layer on the base layer, wherein the surface layer contains at least one selected from the group consisting of (meth)acrylic resin and (meth)acrylic rubber, a plurality of resin particles are present on the outer surface of the surface layer, at least some of the plurality of resin particles are in direct contact with the outer surface of the surface layer, a portion of the outer surface of the electrophotographic member is made up of the resin particles, and the outer surface of the electrophotographic member has irregularities formed by the resin particles, and the resin particles contain a (meth)acrylic-modified silicone resin.

2. The electrophotographic member according to claim 1, wherein said surface layer is an elastic layer containing said (meth)acrylic rubber.

3. The electrophotographic member according to claim 2, wherein when a load-displacement curve is obtained by a nanoindentation test of the elastic layer in accordance with ISO 14577, in which a Vickers indenter is brought into contact with the outer surface of the elastic layer and a test load of 120 μN is applied, the elastic deformation power ηIT calculated from the load-displacement curve is 60 to 90%.

4. The electrophotographic member according to claim 2 or 3, wherein the (meth)acrylic rubber has a structure represented by the following formula (1): In formula (1), R1 represents a methyl group or a hydrogen atom, and R2 represents an alkyl group having 1 to 18 carbon atoms or an alkyl group having 2 to 18 carbon atoms and an ether bond.

5. The electrophotographic member according to claim 1, wherein the surface layer is a resin layer containing the (meth)acrylic resin.

6. The electrophotographic member according to claim 5, wherein the (meth)acrylic resin has a structure represented by the following formula (1'): In formula (1'), R7 represents a methyl group or a hydrogen atom, and R8 represents an alkyl group having 1 to 18 carbon atoms or an alkyl group having 2 to 18 carbon atoms and an ether bond.

7. The electrophotographic member according to any one of claims 1 to 6, wherein the (meth)acrylic-modified silicone resin has a structure represented by the following formula (2) and a structure represented by the following formula (3): -Si(R3)(R4)-O- (2) In formula (2), R3 and R4 each independently represent an alkyl group having 1 to 3 carbon atoms or a hydroxyl group, and in formula (3), R5 represents a hydrogen atom or a methyl group, and R6 represents an alkyl group having 1 to 6 carbon atoms.

8. The electrophotographic member according to claim 7, wherein the ratio of the structure represented by formula (3) in the (meth)acrylic-modified silicone resin is 20 to 40%.

9. The electrophotographic member according to any one of claims 1 to 8, wherein the electrophotographic member is an electrophotographic belt having an endless shape.

10. The electrophotographic member according to claim 9, wherein the outer surface of the electrophotographic member is observed with a scanning electron microscope, and when the length of the electrophotographic member in the longitudinal direction perpendicular to the circumferential direction is W, the number of resin particles present in an observation area of ​​a square of 5 μm length by 5 μm width at any position in a central region of W / 3 from the center of the electrophotographic member in the longitudinal direction toward both ends in the longitudinal direction is 1 to 700.

11. The electrophotographic member according to claim 9 or 10, wherein, when the outer surface of the electrophotographic member is observed with a scanning electron microscope, and the length of the electrophotographic member in the longitudinal direction perpendicular to the circumferential direction is taken as W, the proportion of the area occupied by the resin particles is 50 to 90 area % based on the area of ​​a square observation region measuring 5 μm long x 5 μm wide at an arbitrary position in a central region of W / 3 from the center of the electrophotographic member in the longitudinal direction toward both ends of the electrophotographic member.

12. An electrophotographic image forming apparatus comprising an image forming unit having an image carrier, charging means, image exposure means, and developing means; an intermediate transfer body; a primary transfer member which primarily transfers a toner image formed on said image carrier onto said intermediate transfer body; and a secondary transfer member which secondarily transfers the toner image on said intermediate transfer body using a recording material, wherein said developing means is provided with a toner storage section which stores toner, and said intermediate transfer body is an electrophotographic member as defined in any one of claims 1 to 11.

13. An electrophotographic imaging apparatus according to claim 12, wherein said toner comprises toner particles, said toner particles containing a polyester resin having polyethylene terephthalate segments.

Images