Endless belt, transfer apparatus, and image forming apparatus

Abstract

To provide an endless belt which suppresses occurrence of color omissions and color points of an image.SOLUTION: There is provided an endless belt in which an absolute value of electrostatic capacity C and an absolute value of AC resistance Z when applying the AC voltage of 1 Vp-p from a high frequency side in a range of a frequency from 10000 Hz to 0.1 mHz satisfy a following formula (1), the AC resistance Z0.63 when applying the AC voltage of 1 Vp-p at the frequency of 0.63 Hz satisfies a following formula (2), and the AC resistance Z630 when applying the AC voltage of 1 Vp-p at the frequency of 630 Hz satisfies a following formula (3). The formula (1): log10C≤3.18×log10Z-30.27. The formula (2): 6.3≤log10Z0.63≤6.9. The formula (3): 9.1≤log10Z630≤9.9.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an endless belt, a transfer apparatus, and an image forming apparatus. [Background technology]

[0002] Patent Document 1 proposes "an image forming apparatus comprising a transfer system that forms a strip-shaped transfer nip by contacting a transfer member with an intermediate transfer body on which a toner image is transferred, wherein the transfer system is configured such that the dynamic impedance per unit length in the longitudinal direction of the transfer nip is 0.3 MΩ·m or more and 9.3 MΩ·m or less in all environments, and the toner image on the intermediate transfer body is transferred onto the recording material by applying a transfer bias between the intermediate transfer body and the transfer member while the recording material is held and transported by the transfer nip." Patent Document 2 describes a method comprising: an image carrier; an image forming means for forming a toner image on the image carrier; a primary transfer means for transferring the toner image to an intermediate transfer body; a support member for supporting the intermediate transfer body; and a secondary transfer means for sandwiching a transfer material between the intermediate transfer body and the support member, wherein the ten-point average roughness Rz of the surface of the secondary transfer means that contacts the transfer material JIS An image forming apparatus has been proposed in which the toner image formed on the intermediate transfer body is 7 μm or less, and the impedance Z1 between the surface on the intermediate transfer body where the toner image is formed and the reference potential of the image forming apparatus, and the impedance Z2 between the surface of the secondary transfer means in contact with the transfer material and the reference potential of the image forming apparatus, are both Z1 ≥ Z2. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2000-075675 [Patent Document 2] Japanese Patent Publication No. 2009-150962 [Overview of the project]

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is that when the absolute value of the capacitance C and the absolute value of the AC resistance Z do not satisfy Equation (1) when a 1Vp-p AC voltage is applied from the high-frequency side within the range of 10,000 Hz to 0.1 mHz, the AC resistance Z when a 1Vp-p AC voltage is applied at a frequency of 0.63 Hz 0.63 does not satisfy Equation (2), or the AC resistance Z when a 1Vp-p AC voltage is applied at a frequency of 630 Hz 630 does not satisfy Equation (3), to provide an endless belt in which the occurrence of color bleeding and color dots in an image is suppressed.

Means for Solving the Problems

[0005] The means for solving the above problems include the following means. <1> An endless belt in which the absolute value of the capacitance C and the absolute value of the AC resistance Z satisfy the following Equation (1) when a 1Vp-p AC voltage is applied from the high-frequency side within the range of 10,000 Hz to 0.1 mHz, the AC resistance Z when a 1Vp-p AC voltage is applied at a frequency of 0.63 Hz 0.63 satisfies the following Equation (2), the AC resistance Z when a 1Vp-p AC voltage is applied at a frequency of 630 Hz 630 satisfies the following Equation (3). Equation (1): log 10 C≦3.18×log 10 Z - 30.27 Equation (2): 6.3≦log 10 Z 0.63 ≦6.9 Equation (3): 9.1≦log 10 Z 630 ≦9.9 <2> The endless belt according to <1>, in which the absolute value of the capacitance C and the absolute value of the AC resistance Z satisfy the following Equation (1-2). Equation (1-2): log 10 C≦3.18×log 10 Z - 15.0 <3> The AC resistance Z 630 The following equation (3-3) is satisfied <1> or <2> The endless belt described above. Formula (3-3): 9.4≦log 10 Z 630 ≤9.9 <4> The AC resistance Z 0.63 The following equation (2-4) is satisfied <3> The endless belt described above. Formula (2-4): 6.3≦log 10 Z 0.63 ≤6.5 <5> The absolute value of the capacitance C satisfies the following equation (4-1) <1> ~ <4> An endless belt as described in any one of the following. Formula (4-1): -9.7≦log 10 C <6> An elastic material containing chloroprene rubber and ethylene propylene diene rubber, and a substrate layer containing carbon black, It has a surface layer containing a resin including a fluororesin, The carbon black content is 10% by mass or more and 40% by mass or less relative to the total amount of elastic material contained in the base layer. <1> The endless belt described above. <7> The fluororesin content is 10% by mass or more and 35% by mass or less relative to the total amount of resin contained in the surface layer. <6> The endless belt described above. <8> The thickness of the surface layer is 3 μm or more and 15 μm or less. <7> The endless belt described above. <9> An intermediate transfer body on which a toner image is transferred to the outer surface, A primary transfer apparatus having a primary transfer member that primarily transfers a toner image formed on the surface of an image holder to the outer peripheral surface of an intermediate transfer body, A secondary transfer member is positioned in contact with the outer peripheral surface of the intermediate transfer body and secondarily transfers the toner image transferred to the outer peripheral surface of the intermediate transfer body to the surface of the recording medium, <1> ~ <8> A secondary transfer device having an endless belt as described in any one of the following, A transfer device equipped with the following features. <10> A toner image forming apparatus having an image holder and forming a toner image on the surface of the image holder, A transfer apparatus for transferring the toner image formed on the surface of the image holder to the surface of a recording medium, <9> The transfer apparatus described above, An image forming apparatus equipped with the following features. [Effects of the Invention]

[0006] <1> According to the invention, when an AC voltage of 1Vp-p is applied from the high-frequency side in the range of 10000Hz to 0.1mHz, if the absolute value of capacitance C and the absolute value of AC resistance Z do not satisfy equation (1), then the AC resistance Z when an AC voltage of 1Vp-p is applied at a frequency of 0.63Hz is... 0.63 If equation (2) is not satisfied, or if an AC voltage of 1Vp-p is applied at a frequency of 630Hz, the AC resistance Z 630 An endless belt is provided that suppresses color loss and the occurrence of color spots in the image compared to the case where equation (3) is not satisfied. <2> According to the invention, an endless belt is provided in which color loss and the occurrence of color spots in the image are suppressed compared to the case in which the absolute value of capacitance C and the absolute value of AC resistance Z do not satisfy equation (1-2). <3> According to the invention relating to this invention, AC resistance Z 630 An endless belt is provided that suppresses color loss and the occurrence of color spots in the image compared to the case where equation (3-3) is not satisfied. <4> According to the invention relating to this invention, AC resistance Z 0.63 An endless belt is provided that suppresses color loss and the occurrence of color spots in the image compared to the case where equation (2-4) is not satisfied.

[0007] <5> According to the invention, an endless belt is provided in which color loss and the occurrence of color spots in the image are suppressed compared to the case in which the absolute value of capacitance C does not satisfy equation (4). <6> According to the invention, an endless belt is provided having a base layer containing an elastic material and carbon black, and a surface layer containing a resin containing a fluororesin, in which the occurrence of color fading and color spots in the image is suppressed compared to cases where the elastic material does not contain both chloroprene rubber and ethylene propylene diene rubber, or where the carbon black content is less than 10% by mass or more than 40% by mass relative to the total amount of elastic material contained in the base layer. <7> According to the invention, an endless belt is provided in which the occurrence of color fading and color spots in the image is suppressed compared to cases where the fluororesin content is less than 10% by mass or more than 35% by mass relative to the total resin contained in the surface layer. <8> According to the invention, an endless belt is provided in which color loss and the occurrence of color spots in the image are suppressed compared to cases where the thickness of the surface layer is less than 3 μm or more than 15 μm. <9> or <10> According to the invention, when an AC voltage of 1Vp-p is applied from the high-frequency side in the range of 10000Hz to 0.1mHz, if the absolute value of capacitance C and the absolute value of AC resistance Z do not satisfy equation (1), then the AC resistance Z when an AC voltage of 1Vp-p is applied at a frequency of 0.63Hz is... 0.63 If equation (2) is not satisfied, or if an AC voltage of 1Vp-p is applied at a frequency of 630Hz, the AC resistance Z 630 A transfer apparatus or image forming apparatus is provided that has an endless belt that suppresses color loss and the occurrence of color spots in the image compared to the case where equation (3) is not satisfied. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing an example of an image forming apparatus according to this embodiment. [Figure 2] This is a schematic diagram showing the area around the secondary transfer section in another example of the image forming apparatus according to this embodiment. [Modes for carrying out the invention]

[0009] The following describes an example embodiment of the present invention. These descriptions and examples are illustrative and do not limit the scope of the invention. In numerical ranges described stepwise within this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Furthermore, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values ​​shown in the examples.

[0010] Each component may contain multiple types of the relevant substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition.

[0011] <Endless Belt> In this embodiment, the endless belt satisfies the following equation (1) when an AC voltage of 1Vp-p is applied from the high-frequency side in the range of 10000Hz to 0.1mHz, and the AC resistance Z when an AC voltage of 1Vp-p is applied at a frequency of 0.63Hz. 0.63 The following equation (2) is satisfied, and the AC resistance Z when an AC voltage of 1Vp-p is applied at a frequency of 630Hz is satisfied. 630 This satisfies equation (3) below. Formula (1): log 10 C ≤ 3.18 × log 10 Z-30.27 Equation (2): 6.3≦log 10 Z 0.63 ≤6.9 Equation (3): 9.1≦log 10 Z 630 ≤9.9

[0012] The endless belt according to this embodiment suppresses color loss and the occurrence of color spots in the image due to the above configuration. The reason for this is presumed to be as follows.

[0013] When using a conventional endless belt as a secondary transfer belt, if a voltage is applied in the transfer nip (the region sandwiched between the secondary transfer belt and the back member positioned opposite it), charge tends to remain on the belt. Consequently, when voltage is applied again in the next cycle, the remaining charge can reach the belt surface, causing a lateral flow of the electric field on the belt surface within the transfer nip. This lateral flow of the electric field can result in the toner being partially transferred diagonally onto the recording medium. Furthermore, leakage of the transfer current could cause toner to splatter on the paper, resulting in the appearance of color spots, or abnormal discharge due to insufficient transfer current could cause color loss in the image.

[0014] In this embodiment, the endless belt satisfies equation (1) above in terms of the absolute value of capacitance C and the absolute value of AC resistance Z. This moderately suppresses residual charge on the belt and makes it easier to suppress the generation of lateral flow of electric fields on the belt surface. 0.63 The above equation (2) is satisfied, and the AC resistance Z 630 When the above equation (3) is satisfied, leakage of the transfer current and abnormal discharge due to insufficient transfer current are more easily suppressed.

[0015] Therefore, the endless belt according to this embodiment suppresses color loss and the occurrence of color spots in the image.

[0016] The endless belt according to this embodiment has a base layer containing an elastic material including chloroprene rubber and ethylene propylene diene rubber, as well as carbon black, and a surface layer containing a resin including fluororesin, wherein the carbon black content is preferably 10% by mass or more and 40% by mass or less of the total elastic material contained in the base layer.

[0017] The endless belt according to this embodiment, with the above configuration, further suppresses the occurrence of color loss and color spots in images. The reason for this is presumed to be as follows.

[0018] By having the above-described composition of the base layer and a surface layer that also functions as a dielectric by containing a resin including a fluororesin, the endless belt according to this embodiment is more likely to satisfy the above-described equations (1) to (3).

[0019] Therefore, the endless belt according to this embodiment suppresses color loss and the occurrence of color spots in the image.

[0020] The following describes in detail an endless belt that falls under any of the endless belts according to this embodiment (hereinafter referred to as the endless belt according to this embodiment).

[0021] (Capacitance C and AC resistance Z) In this embodiment, the endless belt satisfies the following equation (1) when an AC voltage of 1Vp-p is applied from the high-frequency side in the range of 10000Hz to 0.1mHz. Formula (1): log 10 C ≤ 3.18 × log 10 Z-30.27

[0022] The absolute values ​​of capacitance C and AC resistance Z preferably satisfy the following equation (1-2). Formula (1-2): log 10 C ≤ 3.18 × log 10 Z-15.0

[0023] When the absolute values ​​of capacitance C and AC resistance Z satisfy equation (1-2) above, the absolute value of capacitance C does not become too large relative to the absolute value of AC resistance Z, thereby more appropriately suppressing residual charge on the belt and making it easier to suppress the generation of lateral electric field flow on the belt surface.

[0024] The absolute value of capacitance C preferably satisfies equation (4-1), more preferably satisfies equation (4-2), and even more preferably satisfies equation (4-3). Formula (4-1): -9.7≦log 10 C Formula (4-2): -9.7≦log 10C ≤ -8.5 Equation (4-3): -9.7≦log 10 C ≤ -9.0

[0025] Capacitance C (unit: F) and AC resistance Z (unit: Ω) are measured by impedance measurement. The specific procedure is as follows: An SI 1260 impedance / gain phase analyzer (manufactured by Toyo Technica Co., Ltd.) is used as the power supply and ammeter, connected to a UR probe (manufactured by Mitsubishi Chemical Corporation), and the UR probe is pressed against the outer surface of the endless belt. An AC voltage of 1Vp-p is applied from the high-frequency side in the frequency range from 10000Hz to 0.1mHz, and impedance measurements are performed to measure capacitance C and AC resistance Z.

[0026] (AC resistance Z 0.63 ) The endless belt according to this embodiment has an AC resistance Z when an AC voltage of 1Vp-p is applied at a frequency of 0.63Hz. 0.63 This satisfies equation (2) below. Equation (2): 6.3≦log 10 Z 0.63 ≤6.9

[0027] From the perspective of further suppressing color loss and the occurrence of color spots in images, AC resistor Z 0.63 It is preferable that the following equation (2-2) is satisfied, more preferably that the following equation (2-3) is satisfied, and even more preferably that the following equation (2-4) is satisfied. Formula (2-2): 6.3≦log 10 Z 0.63 ≤6.7 Formula (2-3): 6.3≦log 10 Z 0.63 ≤6.6 Formula (2-4): 6.3≦log 10 Z 0.63 ≤6.5

[0028] AC resistance Z 0.63 When equations (2-2) to (2-4) are satisfied, leakage of the transfer current and abnormal discharge due to insufficient transfer current are more easily suppressed.

[0029] (AC resistance Z 630 ) The endless belt according to this embodiment has an AC resistance Z when an AC voltage of 1Vp-p is applied at a frequency of 630Hz. 630 This satisfies equation (3) below. Equation (3): 9.1≦log 10 Z 630 ≤9.9

[0030] From the perspective of further suppressing color loss and the occurrence of color spots in images, AC resistor Z 630 It is preferable that the following equation (3-2) is satisfied, more preferably that the following equation (3-3) is satisfied, and even more preferably that the following equation (3-4) is satisfied. Formula (3-2): 9.3≦log 10 Z 630 ≤9.9 Formula (3-3): 9.4≦log 10 Z 630 ≤9.9 Formula (3-4): 9.4≦log 10 Z 630 ≤9.6

[0031] AC resistance Z 630 When equations (3-2) to (3-4) are satisfied, leakage of the transfer current and abnormal discharge due to insufficient transfer current are more easily suppressed.

[0032] AC resistance Z 0.63 and AC resistance Z 630 The measurement of impedance (both in units of Ω) is performed by impedance measurement. The specific procedure is as follows: An SI 1260 impedance / gain phase analyzer (manufactured by Toyo Technica Co., Ltd.) is used as the power supply and ammeter, connected to a UR probe (manufactured by Mitsubishi Chemical Corporation), and the UR probe is pressed against the outer surface of the endless belt. Impedance measurements were performed while applying an AC voltage of 1Vp-p at a frequency of 0.63Hz, and the AC resistance Z was measured. 0.63 Measure. Impedance measurements were performed while applying an AC voltage of 1Vp-p at a frequency of 630Hz, and the AC resistance Z was measured. 630Measure.

[0033] (Construction of an endless belt) In this embodiment, the endless belt preferably has a base layer and a surface layer. The surface layer is preferably provided on the outer circumferential surface of the base material layer, and may be provided on the inner circumferential surface of the base material layer if necessary. The surface layer provided on the outer circumferential surface of the base material layer constitutes the outer circumferential surface of the endless belt. The surface layer provided on the inner circumferential surface of the base material layer constitutes the inner circumferential surface of the endless belt.

[0034] -Base material layer- The base layer preferably contains an elastic material. Examples of elastic materials include rubber and resin.

[0035] Examples of rubbers include chloroprene rubber, epichlorohydrin rubber, isoprene rubber, butyl rubber, polyurethane, silicone rubber, fluororubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber (NBR), ethylene propylene rubber, ethylene propylene diene rubber (EPDM), natural rubber, and mixtures thereof.

[0036] Examples of resins include polyamide, polyimide, polyamideimide, polyetherimide, polyetheretherketone, polyphenylene sulfide, polyethersulfone, polyphenylsulfone, polysulfone, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polycarbonate, polyester, and mixtures thereof.

[0037] From the viewpoint of further suppressing color loss and the occurrence of color spots in images, the elastic material preferably contains rubber, and more preferably contains chloroprene rubber and ethylene propylene diene rubber. When the elastic material contains chloroprene rubber and ethylene propylene diene rubber, the ratio of the chloroprene rubber content to the ethylene propylene diene rubber content (chloroprene rubber content / ethylene propylene diene rubber content) is preferably 1 to 100 by mass, more preferably 3 to 50, and even more preferably 5 to 20.

[0038] The substrate layer preferably contains conductive particles. Examples of conductive particles include carbon blacks such as Ketjenblack, oil furnace black, channel black, and acetylene black; metal particles such as aluminum and nickel; and metal oxide particles such as indium tin oxide, tin oxide, zinc oxide, titanium oxide, and yttrium oxide. From the viewpoint of further suppressing color loss and the occurrence of color spots in images, carbon black is preferred as the conductive particle. One type of conductive particle may be used alone, or two or more types may be used in combination.

[0039] The average primary particle size of the conductive particles is preferably 1 nm to 150 nm, more preferably 3 nm to 100 nm, and even more preferably 5 nm to 50 nm.

[0040] The content of conductive particles is preferably 10% to 40% by mass, more preferably 10% to 35% by mass, and even more preferably 15% to 30% by mass, relative to the total elastic material contained in the base layer.

[0041] The substrate layer may contain conductive agents other than conductive particles. Examples of conductive agents include ionic conductive substances such as potassium titanate, potassium chloride, sodium perchlorate, and lithium perchlorate; and ionic conductive polymers such as polyaniline, polyether, polypyrrole, polysulfone, and polyacetylene. One conductive agent may be used alone, or two or more may be used in combination.

[0042] The base layer may contain additives such as antioxidants, crosslinking agents, flame retardants, colorants, surfactants, dispersants, and fillers.

[0043] The thickness of the substrate layer is preferably 400 μm to 800 μm, more preferably 420 μm to 600 μm, and even more preferably 440 μm to 500 μm.

[0044] -Surface layer- The surface layer preferably contains a resin (hereinafter, the resin contained in the surface layer will be referred to as the "surface layer resin"). The surface layer resin preferably contains a fluororesin. Examples of fluororesins include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluoroethylene chloride resin, and copolymers thereof. Among these, polytetrafluoroethylene (PTFE) is preferred as the fluororesin from the viewpoint of further suppressing color loss and the occurrence of color spots in images.

[0045] The surface layer resin preferably contains urethane resin along with fluororesin. Urethane resin (also called polyurethane or urethane rubber) is generally synthesized by polymerizing polyisocyanate and polyol. It is preferable that the urethane resin has both a hard segment and a soft segment.

[0046] The fluororesin content is preferably 10% to 35% by mass, more preferably 15% to 33% by mass, and even more preferably 20% to 30% by mass, relative to the total resin content in the surface layer.

[0047] By setting the fluororesin content to 10% by mass or more relative to the total resin content in the surface layer, the amount of fluororesin in the surface layer becomes sufficient to further improve the dielectric function of the surface layer. Furthermore, by limiting the fluororesin content to 35% by mass or less relative to the total resin content in the surface layer, it becomes possible to secure the mechanical strength necessary for crack resistance of the surface layer.

[0048] The surface layer may contain additives such as antioxidants, crosslinking agents, flame retardants, colorants, and fillers.

[0049] The thickness of the surface layer is preferably 3 μm to 15 μm, more preferably 4 μm to 12 μm, and even more preferably 7 μm to 10 μm.

[0050] The thickness of the surface layer is measured using an optical microscope. For example, the Keyence Digital Microscope VHX can be used as an optical microscope. The procedure for measuring the thickness of the surface layer is as follows: The endless belt is cut in the thickness direction. The resulting cross-section is observed, and the thickness of the surface layer is measured by taking an image with an optical microscope.

[0051] (Manufacturing method for endless belts) One example of a method for manufacturing an endless belt is to prepare a tubular member that will serve as the base layer, and then form a surface layer on at least one of the outer and inner surfaces of the tubular member.

[0052] Methods for manufacturing tubular members include, for example, extrusion molding, in which a composition containing an elastic material and conductive particles is melted and extruded in a belt shape from a die and solidified; injection molding, in which a composition containing an elastic material and conductive particles is melted and placed in a belt-shaped mold and solidified; and coating molding, in which a composition containing an elastic material precursor or monomer and conductive particles is applied to a core body and solidified.

[0053] Methods for forming the surface layer include, for example, applying a liquid composition containing a resin including a fluororesin to at least one of the outer and inner surfaces of a tubular member and allowing it to solidify; or applying a liquid composition containing a precursor or monomer of a surface layer resin other than fluororesin and a fluororesin to the outer or inner surface of a tubular member and allowing it to solidify. Depending on the type of components, drying, heating, electron beam irradiation, or ultraviolet irradiation may be performed to solidify the liquid composition.

[0054] <Transfer device> The transfer apparatus according to this embodiment comprises an intermediate transfer body on which a toner image is transferred to its outer peripheral surface; a primary transfer apparatus having a primary transfer member that primary transfers a toner image formed on the surface of an image holder to the outer peripheral surface of the intermediate transfer body; and a secondary transfer apparatus having a secondary transfer member that is positioned in contact with the outer peripheral surface of the intermediate transfer body and secondary transfers the toner image transferred to the outer peripheral surface of the intermediate transfer body to the surface of a recording medium.

[0055] In the primary transfer device, the primary transfer member is positioned opposite the image holder, with the intermediate transfer body in between. In the primary transfer device, the primary transfer member applies a voltage with the opposite polarity to the charge polarity of the toner to the intermediate transfer body, thereby primary transferring the toner image to the outer surface of the intermediate transfer body.

[0056] In a secondary transfer apparatus, the secondary transfer member is positioned on the toner image holding side of the intermediate transfer body. The secondary transfer apparatus also includes, for example, a back member positioned on the opposite side of the intermediate transfer body from the toner image holding side, together with the secondary transfer member. In the secondary transfer apparatus, the toner image on the intermediate transfer body is secondary transferred to the recording medium by sandwiching the intermediate transfer body and the recording medium between the secondary transfer member and the back member to form a transfer field. The secondary transfer member may be a secondary transfer roll or a secondary transfer belt. For example, a backing roll may be used as the backing member.

[0057] From the viewpoint of suppressing color loss and the occurrence of color spots in the image, the secondary transfer member is a secondary transfer belt, and it is preferable to use the endless belt according to this embodiment as the secondary transfer belt. In other words, the transfer apparatus according to this embodiment preferably comprises an intermediate transfer body on which a toner image is transferred to its outer peripheral surface, a primary transfer apparatus having a primary transfer member that primary transfers a toner image formed on the surface of an image holder to the outer peripheral surface of the intermediate transfer body, and a secondary transfer apparatus having an endless belt according to this embodiment, which is arranged in contact with the outer peripheral surface of the intermediate transfer body and secondary transfers the toner image transferred to the outer peripheral surface of the intermediate transfer body to the surface of a recording medium.

[0058] Furthermore, the transfer apparatus according to this embodiment may be a transfer apparatus that transfers a toner image to the surface of a recording medium via a plurality of intermediate transfer bodies. In other words, the transfer apparatus may be, for example, a transfer apparatus that first transfers the toner image from an image holder to a first intermediate transfer body, then secondarily transfers the toner image from the first intermediate transfer body to a second intermediate transfer body, and finally tertiarily transfers the toner image from the second intermediate transfer body to the recording medium.

[0059] <Image forming apparatus> The image forming apparatus according to this embodiment comprises a toner image forming apparatus for forming a toner image on the surface of an image holder, and a transfer apparatus for transferring the toner image formed on the surface of the image holder to the surface of a recording medium. The transfer apparatus according to this embodiment is applied.

[0060] An example of a toner image forming apparatus is one comprising: an image holder; a charging device for charging the surface of the image holder; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the image holder; and a developing device for developing the electrostatic latent image formed on the surface of the image holder with a developer containing toner to form a toner image.

[0061] The image forming apparatus according to this embodiment includes a fixing means for fixing a toner image transferred to the surface of a recording medium; a cleaning means for cleaning the surface of an image holder before charging after the transfer of the toner image; a static elimination means for irradiating the surface of an image holder with static elimination light to eliminate static charge after the transfer of the toner image before charging; and a well-known image forming apparatus including an image holder heating member for raising the temperature of the image holder and reducing the relative temperature.

[0062] The image forming apparatus according to this embodiment may be either a dry developing type image forming apparatus or a wet developing type image forming apparatus (a developing method using a liquid developer).

[0063] In the image forming apparatus according to this embodiment, for example, the part comprising the image holder may be a cartridge structure (process cartridge) that can be attached to and detached from the image forming apparatus. As the process cartridge, for example, a process cartridge comprising a toner image forming apparatus and a transfer apparatus is preferably used.

[0064] Hereinafter, an example of an image forming apparatus according to this embodiment will be described with reference to the drawings. However, the image forming apparatus according to this embodiment is not limited to this example. The main parts shown in the drawings will be described, and other parts will be omitted from the description.

[0065] (Image forming apparatus) Figure 1 is a schematic diagram showing the configuration of the image forming apparatus according to this embodiment.

[0066] As shown in Figure 1, the image forming apparatus 100 according to this embodiment is, for example, an intermediate transfer type image forming apparatus generally called a tandem type, and comprises a plurality of image forming units 1Y, 1M, 1C, 1K (an example of a toner image forming apparatus) in which toner images of each color component are formed by an electrophotographic method; a primary transfer unit 10 that sequentially transfers (primary transfer) the toner images of each color component formed by each image forming unit 1Y, 1M, 1C, 1K to an intermediate transfer belt 15; a secondary transfer unit 20 that transfers (secondary transfer) the superimposed toner images transferred on the intermediate transfer belt 15 to a recording medium, paper K, in one go; and a fixing device 60 that fixes the secondary transferred image onto the paper K. The image forming apparatus 100 also has a control unit 40 that controls the operation of each device (each part).

[0067] Each image forming unit 1Y, 1M, 1C, 1K of the image forming apparatus 100 is equipped with a photoreceptor 11 (an example of an image holder) that rotates in the direction of arrow A and holds the toner image formed on its surface.

[0068] Around the photoreceptor 11, a charger 12 is provided as an example of a charging means for charging the photoreceptor 11, and a laser exposure unit 13 (indicated by the symbol Bm in the figure) is provided as an example of a latent image forming means for writing an electrostatic latent image onto the photoreceptor 11.

[0069] Furthermore, surrounding the photoreceptor 11, as an example of a developing means, is a developer 14 which contains toners for each color component and visualizes the electrostatic latent image on the photoreceptor 11 using the toner, and a primary transfer roll 16 which transfers the toner images for each color component formed on the photoreceptor 11 to an intermediate transfer belt 15 in a primary transfer unit 10.

[0070] Furthermore, a photoreceptor cleaner 17 is provided around the photoreceptor 11 to remove any residual toner on the photoreceptor 11, and the electrophotographic devices, including the charger 12, laser exposure unit 13, developer unit 14, primary transfer roll 16, and photoreceptor cleaner 17, are sequentially arranged along the rotational direction of the photoreceptor 11. These image forming units 1Y, 1M, 1C, and 1K are arranged in a substantially straight line from the upstream side of the intermediate transfer belt 15 in the order of yellow (Y), magenta (M), cyan (C), and black (K).

[0071] The intermediate transfer belt 15 is driven (rotated) in a circulating manner at a speed appropriate to the purpose in direction B shown in Figure 1 by various rolls. These various rolls include a drive roll 31 that rotates the intermediate transfer belt 15 by a motor (not shown) with excellent constant-speed performance, a support roll 32 that supports the intermediate transfer belt 15 which extends substantially linearly along the arrangement direction of each photoreceptor 11, a tension-applying roll 33 that applies tension to the intermediate transfer belt 15 and functions as a correction roll to prevent the intermediate transfer belt 15 from meandering, a back roll 25 provided in the secondary transfer section 20, and a cleaning back roll 34 provided in the cleaning section that scrapes off residual toner on the intermediate transfer belt 15.

[0072] The primary transfer section 10 consists of a primary transfer roll 16 positioned opposite the photoreceptor 11, with the intermediate transfer belt 15 in between. The primary transfer roll 16 is pressed against the photoreceptor 11 with the intermediate transfer belt 15 in between, and a voltage (primary transfer bias) with the opposite polarity to the charge polarity of the toner (negative polarity; the same applies hereinafter) is applied to the primary transfer roll 16. As a result, the toner images on each photoreceptor 11 are sequentially electrostatically attracted to the intermediate transfer belt 15, and superimposed toner images are formed on the intermediate transfer belt 15.

[0073] The secondary transfer section 20 comprises a back roll 25 and a secondary transfer roll 22 positioned on the toner image holding surface side of the intermediate transfer belt 15.

[0074] Back roll 25 has a surface resistivity of 1 × 10 7 Ω / □ or more 1×10 10 It is formed to be less than or equal to Ω / □, and its hardness is set to, for example, 70° (Asker C: manufactured by Polymer Instruments, the same applies hereafter). This back roll 25 is positioned on the back side of the intermediate transfer belt 15 and constitutes the opposing electrode of the secondary transfer roll 22, and is in contact with a metal power supply roll 26 to which the secondary transfer bias is stably applied.

[0075] On the other hand, the secondary transfer roll 22 has a volume resistivity of 10 7.5 Ωcm or more 10 8.5 It is a cylindrical roll with a diameter of Ωcm or less. The secondary transfer roll 22 is pressed against the back roll 25 with the intermediate transfer belt 15 in between, and the secondary transfer roll 22 is grounded to form a secondary transfer bias between it and the back roll 25, thereby secondary transferring the toner image onto the paper K that is transported to the secondary transfer section 20.

[0076] Furthermore, an intermediate transfer belt cleaning member 35 is provided downstream of the secondary transfer section 20 of the intermediate transfer belt 15, which can be moved toward and away from the intermediate transfer belt 15 to remove residual toner and paper dust on the intermediate transfer belt 15 after secondary transfer and to clean the outer surface of the intermediate transfer belt 15. Furthermore, a secondary transfer roll cleaning member 22A is provided downstream of the secondary transfer section 20 of the secondary transfer roll 22 to remove residual toner and paper dust from the secondary transfer roll 22 after secondary transfer and to clean the outer surface of the intermediate transfer belt 15. The secondary transfer roll cleaning member 22A is exemplified by a cleaning blade. However, it may also be a cleaning roll.

[0077] The intermediate transfer belt 15, primary transfer roll 16, and secondary transfer roll 22 are examples of a transfer device. Here, from the viewpoint of suppressing color loss and the occurrence of color spots in the image, the image forming apparatus 100 is configured to include a secondary transfer belt (an example of a secondary transfer member) instead of a secondary transfer roll 22, and it is preferable to use the endless belt according to this embodiment as the secondary transfer belt. Specifically, as shown in Figure 2, it is preferable that the image forming apparatus 100 includes a secondary transfer device comprising a secondary transfer belt 23, a drive roll 23A arranged opposite to the back roll 25 via an intermediate transfer belt 15 and the secondary transfer belt 23, and an idler roll 23B that tensions the secondary transfer belt 23 together with the drive roll 23A. And it is preferable to use the endless belt according to this embodiment as the secondary transfer belt 23.

[0078] On the other hand, upstream of the yellow image forming unit 1Y, a reference sensor (home position sensor) 42 is provided that generates a reference signal which serves as a reference for determining the image forming timing in each image forming unit 1Y, 1M, 1C, and 1K. Downstream of the black image forming unit 1K, an image density sensor 43 is provided for adjusting image quality. This reference sensor 42 recognizes a mark provided on the back of the intermediate transfer belt 15 and generates a reference signal. Based on the recognition of this reference signal, each image forming unit 1Y, 1M, 1C, and 1K is configured to start image forming according to instructions from the control unit 40.

[0079] Furthermore, the image forming apparatus according to this embodiment includes, as a means for transporting paper K, a paper storage section 50 for storing paper K, a paper feed roll 51 for taking out and transporting paper K accumulated in the paper storage section 50 at a predetermined timing, a transport roll 52 for transporting paper K fed out by the paper feed roll 51, a transport guide 53 for sending paper K transported by the transport roll 52 to the secondary transfer section 20, a transport belt 55 for transporting paper K that has been secondarily transferred by the secondary transfer roll 22 to the fixing device 60, and a fixing inlet guide 56 for guiding paper K to the fixing device 60.

[0080] Next, the basic image formation process of the image forming apparatus according to this embodiment will be described. In the image forming apparatus according to this embodiment, image data output from an image reading device (not shown) or a personal computer (PC) (not shown) is processed by an image processing device (not shown), and then image formation is performed by image forming units 1Y, 1M, 1C, and 1K.

[0081] The image processing device applies various image processing steps to the input reflectance data, including shading correction, positional shift correction, brightness / color space conversion, gamma correction, frame removal, color editing, and movement editing. The processed image data is converted into four-color chromatic data (Y, M, C, K) and output to the laser exposure unit 13.

[0082] In the laser exposure unit 13, according to the input color tone data, an exposure beam Bm emitted from, for example, a semiconductor laser is irradiated onto each of the photoreceptors 11 of the image forming units 1Y, 1M, 1C, and 1K. After the surface of each photoreceptor 11 of the image forming units 1Y, 1M, 1C, and 1K is charged by the charger 12, the surface is scanned and exposed by the laser exposure unit 13, and an electrostatic latent image is formed. The formed electrostatic latent image is then developed as toner images of the respective colors Y, M, C, and K by the respective image forming units 1Y, 1M, 1C, and 1K.

[0083] The toner images formed on the photoreceptors 11 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 15 in the primary transfer section 10, where each photoreceptor 11 comes into contact with the intermediate transfer belt 15. More specifically, in the primary transfer section 10, a primary transfer roll 16 applies a voltage (primary transfer bias) with the opposite polarity to the toner's charge polarity (negative polarity) to the substrate of the intermediate transfer belt 15, and the toner images are sequentially superimposed on the outer surface of the intermediate transfer belt 15 to perform primary transfer.

[0084] After the toner image is sequentially transferred to the outer surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves and the toner image is transported to the secondary transfer section 20. When the toner image is transported to the secondary transfer section 20, the transport mechanism rotates the paper feed roll 51 in time with the transport of the toner image to the secondary transfer section 20, and paper K of the desired size is supplied from the paper storage section 50. The paper K supplied by the paper feed roll 51 is transported by the transport roll 52 and reaches the secondary transfer section 20 via the transport guide 53. Before reaching the secondary transfer section 20, the paper K is temporarily stopped, and the position of the paper K and the position of the toner image are aligned by rotating the alignment roll (not shown) in time with the movement of the intermediate transfer belt 15 holding the toner image.

[0085] In the secondary transfer section 20, the secondary transfer roll 22 is pressed against the back roll 25 via the intermediate transfer belt 15. At this time, the paper K, which has been transported in sync with the timing, is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. When a voltage (secondary transfer bias) with the same polarity as the charge polarity (negative polarity) of the toner is applied from the power supply roll 26, a transfer electric field is formed between the secondary transfer roll 22 and the back roll 25. Then, the unfixed toner image held on the intermediate transfer belt 15 is electrostatically transferred all at once onto the paper K in the secondary transfer section 20, which is pressed by the secondary transfer roll 22 and the back roll 25.

[0086] Subsequently, the paper K on which the toner image has been electrostatically transferred is peeled off the intermediate transfer belt 15 by the secondary transfer roll 22 and transported to the transport belt 55 located downstream of the secondary transfer roll 22 in the paper transport direction. The transport belt 55 transports the paper K to the fuser 60 at an optimal transport speed for the fuser 60. The unfixed toner image on the paper K transported to the fuser 60 is fixed to the paper K by the fuser 60 through a fixing process using heat and pressure. The paper K with the fixed image then transported to the paper discharge and storage section (not shown) located in the discharge section of the image forming apparatus.

[0087] Meanwhile, after the transfer to paper K is completed, any residual toner remaining on the intermediate transfer belt 15 is transported to the cleaning section as the intermediate transfer belt 15 rotates, and is removed from the intermediate transfer belt 15 by the cleaning back roll 34 and the intermediate transfer belt cleaner 35.

[0088] Although this embodiment has been described above, it is not intended to be interpreted as being limited to the above embodiment, and various modifications, changes, and improvements are possible. [Examples]

[0089] Examples are described below, but the present invention is not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" all refer to mass.

[0090] <Example 1> (Preparation of the base layer) A mixture of chloroprene rubber, an elastic material, and carbon black, conductive particles (carbon black content of 25% by mass of the total mixture) was mixed with 15 parts of ethylene propylene diene rubber, an elastic material. The mixture was extruded using a kneading extruder to obtain a molded product. The molded product was dried with hot air to obtain a tubular body with a diameter (outer diameter) of 40 mm and a thickness of 450 μm. The tubular body was cut to a length of 355 mm to form a base layer.

[0091] (Preparation of the surface layer) A coating solution was prepared by adding 1% by mass of a curing agent (Loctite WH-1, manufactured by Henkel Japan) to a urethane resin (Bonderite T862A, manufactured by Henkel Japan) containing tetrafluoroethylene resin, a type of fluororesin, and diluting it with water (the total content of tetrafluoroethylene resin in the coating solution was 20% by mass). With the substrate layer's central axis oriented horizontally, the coating solution was sprayed onto the outer surface of the substrate layer while rotating it. Next, hot air drying was performed at 150°C for 35 minutes to form a surface layer on the outer surface of the substrate layer (hereinafter, the surface layer formed on the outer surface of the substrate layer will be referred to as the "outer surface layer"). The thickness of the outer surface layer was 8 μm. The coating solution was similarly sprayed onto the inner surface of the substrate layer, and the same hot air drying procedure was performed to form a surface layer on the inner surface of the substrate layer (hereinafter, the surface layer formed on the inner surface of the substrate layer will be referred to as the "inner surface layer"). The thickness of the inner surface layer was set to 5 μm. An endless belt was obtained using the procedure described above.

[0092] <Example 2> In the preparation of the base layer, an endless belt was obtained using the same procedure as in Example 1, except that the carbon black content relative to the total mixture of chloroprene rubber and carbon black was changed from 25% by mass to 15% by mass.

[0093] <Example 3> In the preparation of the base layer, an endless belt was obtained using the same procedure as in Example 1, except that the carbon black content relative to the total mixture of chloroprene rubber and carbon black was changed from 25% by mass to 30% by mass.

[0094] <Comparative Example 1> An endless belt was obtained using the same procedure as in Example 1, except that the carbon black content relative to the total mixture of chloroprene rubber and carbon black was changed from 25% by mass to 15% by mass in the preparation of the base layer, and ethylene propylene diene rubber was not added.

[0095] <Comparative Example 2> I prepared the secondary transfer belt for the Iridesse Digital Press (manufactured by Fujifilm Business Innovation).

[0096] <Comparative Example 3> I prepared the secondary transfer belt for the Color1000 Press (manufactured by Fujifilm Business Innovation).

[0097] <Comparative Example 4> An endless belt was obtained using the same procedure as in Example 1, except that in the preparation of the base layer, the carbon black content relative to the total mixture of chloroprene rubber and carbon black was changed from 25% by mass to 30% by mass; in the preparation of the surface layer, Bonderite T845B, manufactured by Henkel Japan, was used instead of a urethane resin containing tetrafluoroethylene resin (Bonderite T862A, manufactured by Henkel Japan), which is a fluororesin; and the thickness of the outer surface layer was set to 12 μm.

[0098] <Example 4> In the preparation of the base layer, the carbon black content relative to the total mixture of chloroprene rubber and carbon black was changed from 25% by mass to 30% by mass. In the preparation of the surface layer, DM-A6000, manufactured by Daizo, was used instead of a urethane resin containing tetrafluoroethylene resin (Bonderite T862A, manufactured by Henkel Japan), which is a fluororesin. The procedure was the same as in Example 1 to obtain an endless belt.

[0099] <Rating> The endless belts obtained in each example were attached to the ApeosPro C810 (Fujifilm Business Innovation Co., Ltd.) as secondary transfer belts and evaluated according to the following procedure.

[0100] (Image evaluation) The image was evaluated by printing 20mm x 20mm cyan image patches on A3-sized coated paper, varying the image density from 10% to 100% in 10% increments, and observing the patch that exhibited the most graininess. -Evaluation Criteria- A: No dead pixels (dead pixels are caused by color loss or the appearance of color spots in the image; the same applies hereinafter) are visible when observed with the naked eye or with a magnifying glass. B: While no dead pixels are visible to the naked eye, some dead pixels can be observed when viewed with a magnifying glass. C: There are visible dead pixels. D: The dot itself is missing and cannot be seen.

[0101] (Paper handling performance evaluation) The evaluation was performed by printing on A3-sized tracing paper (equivalent to 40gsm) from the manual feed tray. -Evaluation Criteria- A: Output normally. B: The document is printed, but wrinkles in the paper are visible to the naked eye. C: A paper jam has occurred, and printing is not possible.

[0102] [Table 1]

[0103] Let me explain the information in Table 1. log 10 Minimum value of C: Logarithm of the absolute value of capacitance C obtained in impedance measurement (log) 10 This shows the minimum value of C. log 10 Maximum value of C: Logarithm of the absolute value of capacitance C obtained in impedance measurement (log) 10 This shows the maximum value among C. 3.18 × log 10 Minimum value of Z-30.27: Calculated using the absolute value of the AC resistance Z obtained in the impedance measurement: 3.18 × log 10 This shows the minimum value among the values ​​of Z-30.27. 3.18 × log 10 Minimum value of Z-15.0: Calculated using the absolute value of the AC resistance Z obtained in impedance measurement (3.18 × log 10 This shows the minimum value among the Z-15.0 values. ·log 10 C 0.63 : The common logarithm of the absolute value of the capacitance C measured by the procedure described below. 0.63 is. ·log 10 C 630 : The common logarithm of the absolute value of the capacitance C measured by the procedure described below. 630 is. · Type of elastic material: "CR" is chloroprene rubber and "EPDM" is ethylene propylene diene rubber. · CB content (%): The content of carbon black with respect to the entire elastic material contained in the base material layer. · Fluororesin content (%): The content of fluororesin with respect to the entire resin contained in the surface layer.

[0104] · Capacitance C 0.63 and capacitance C 630 measurement procedure Capacitance C 0.63 and capacitance C 630 (both in units of F) are measured by impedance measurement. The specific procedure is as follows. Connect a UR probe (manufactured by Mitsubishi Chemical Corporation) to an SI 1260 inpedance / gain phase analyzer (manufactured by Toyo Technica Corporation) as a power supply and ammeter, and press the UR probe against the outer peripheral surface of the endless belt. Perform impedance measurement while applying an AC voltage of 1 Vp-p at a frequency of 0.63 Hz to measure the capacitance C 0.63 . Perform impedance measurement while applying an AC voltage of 1 Vp-p at a frequency of 630 Hz to measure the capacitance C 630 .

[0105] From the above results, it can be seen that the endless belt of this embodiment suppresses the occurrence of color bleeding and color spots in the image.

[0106] ((1)) When an AC voltage of 1 Vp-p is applied from the high-frequency side within the range from a frequency of 10,000 Hz to 0.1 mHz, the absolute value of the capacitance C and the absolute value of the AC resistance Z satisfy the following formula (1), The AC resistance Z when an AC voltage of 1 Vp-p is applied at a frequency of 0.63 Hz 0.63 satisfies the following formula (2), The AC resistance Z when an AC voltage of 1 Vp-p is applied at a frequency of 630 Hz 630 An endless belt that satisfies the following formula (3). Formula (1): log 10 C ≦ 3.18 × log 10 Z - 30.27 Formula (2): 6.3 ≦ log 10 Z 0.63 ≦ 6.9 Formula (3): 9.1 ≦ log 10 Z 630 ≦ 9.9 ((2)) The endless belt according to ((1)), wherein the absolute value of the capacitance C and the absolute value of the AC resistance Z satisfy the following formula (1-2). Formula (1-2): log 10 C ≦ 3.18 × log 10 Z - 15.0 ((3)) The endless belt according to ((1)) or ((2)), wherein the AC resistance Z 630 satisfies the following formula (3-3). Formula (3-3): 9.4 ≦ log 10 Z 630 ≦ 9.9 ((4)) The endless belt according to ((3)), wherein the AC resistance Z 0.63 satisfies the following formula (2-4). Formula (2-4): 6.3 ≦ log 10 Z 0.63 ≦ 6.5 ((5)) The endless belt according to any one of ((1)) to ((4)), wherein the absolute value of the capacitance C satisfies the following formula (4-1). 10 C (((6))) An elastic material containing chloroprene rubber and ethylene propylene diene rubber, and a base layer containing carbon black, It has a surface layer containing a resin including a fluororesin, The endless belt according to (((1))), wherein the carbon black content is 10% by mass or more and 40% by mass or less of the total elastic material contained in the base layer. (((7))) The endless belt according to (((6))), wherein the content of the fluororesin is 10% by mass or more and 35% by mass or less of the total resin contained in the surface layer. (8)) The endless belt according to (7), wherein the thickness of the surface layer is 3 μm or more and 15 μm or less. (((9))) An intermediate transfer body on which a toner image is transferred to the outer surface, A primary transfer apparatus having a primary transfer member that primarily transfers a toner image formed on the surface of an image holder to the outer peripheral surface of an intermediate transfer body, A secondary transfer member is positioned in contact with the outer circumferential surface of the intermediate transfer body and secondarily transfers the toner image transferred to the outer circumferential surface of the intermediate transfer body to the surface of a recording medium, and the secondary transfer device has an endless belt as described in any one of (((1))) to (((8))), A transfer device equipped with the following features. (((10))) A toner image forming apparatus having an image holder and forming a toner image on the surface of the image holder, A transfer apparatus for transferring the toner image formed on the surface of the image holder to the surface of a recording medium, the transfer apparatus described in (((9))), An image forming apparatus equipped with the following features. [Explanation of symbols]

[0107] 1Y, 1M, 1C, 1K Image Forming Unit 10 Primary Transfer Section 11 Photoreceptor 12 Chargers 13. Laser exposure unit 14. Developer 15 Intermediate transfer belt 16 Primary transfer roll 17 Photoconductor Cleaner 20 Secondary transfer section 22 Secondary transfer roll 22A Secondary transfer roll cleaning member 25 Back Roll 26 Power supply roll 31 Drive Roll 32 support rolls 33 Tension-applying roll 34 Cleaning back roll 35 Intermediate transfer belt cleaning member 40 Control Unit 42 Reference Sensor 43 Image density sensor 50 Paper storage compartments 51 Paper feed roll 52 Conveyor Rolls 53 Conveyor Guide 55 Conveyor belt 56 Fixing entrance guide 60 Fixing device 100 Image forming apparatus

Claims

1. When an AC voltage of 1 Vp-p is applied from the high-frequency side in the range of 10,000 Hz to 0.1 mHz, the absolute value of the capacitance C (unit: F) and the absolute value of the AC resistance Z (unit: Ω) satisfy the following equation (1): AC resistance Z when an AC voltage of 1 Vp-p is applied at a frequency of 0.63 Hz. ０．６３ The following equation (2) is satisfied, AC resistance Z when an AC voltage of 1 Vp-p is applied at a frequency of 630 Hz. ６３０ The following equation (3) is satisfied, An elastic material containing chloroprene rubber and ethylene propylene diene rubber, and a substrate layer containing carbon black, It has a surface layer containing a resin including a fluororesin, The carbon black content is 10% by mass or more and 40% by mass or less relative to the total amount of the elastic material contained in the base layer. The thickness of the surface layer is 3 μm or more and 15 μm or less. An endless belt in which the measurement methods for capacitance C (unit: F) and AC resistance (unit: Ω) are as follows. Formula (1): log １０ C≦3.18×log １０ Z-30.27 Equation (2): 6.3≦log １０ Z ０．６３ ≤6.9 Equation (3): 9.1≦log １０ Z ６３０ ≤9.9 Measurement methods for capacitance C (unit: F) and AC resistance Z (unit: Ω): Connect the UR probe to the power supply and ammeter, and press the UR probe against the outer surface of the endless belt. An AC voltage of 1 Vp-p is applied from the high-frequency side within the frequency range of 10,000 Hz to 0.1 mHz, and impedance measurements are taken to determine capacitance C (unit: F) and AC resistance Z (unit: Ω).

2. The endless belt according to claim 1, wherein the absolute value of the capacitance C and the absolute value of the AC resistance Z satisfy the following formula (1-2). Equation (1-2): log １０ C≦3.18×log １０ Z-15.0

3. The AC resistance Z ６３０ The endless belt according to claim 1, wherein the following formula (3-3) is satisfied. Equation (3-3): 9.4≦log １０ Z ６３０ ≤9.9

4. The AC resistance Z ０．６３ The endless belt according to claim 3, wherein the following formula (2-4) is satisfied. Equation (2-4): 6.3≦log １０ Z ０．６３ ≤6.5

5. The endless belt according to claim 1, wherein the absolute value of the capacitance C satisfies the following formula (4-1). Equation (4-1): -9.7≦log １０ C

6. The endless belt according to claim 1, wherein the content of the fluororesin is 10% by mass or more and 35% by mass or less of the total resin contained in the surface layer.

7. An intermediate transfer body on which a toner image is transferred to the outer surface, A primary transfer apparatus having a primary transfer member that primarily transfers a toner image formed on the surface of an image holder to the outer peripheral surface of an intermediate transfer body, A secondary transfer member is positioned in contact with the outer circumferential surface of the intermediate transfer body and secondarily transfers the toner image transferred to the outer circumferential surface of the intermediate transfer body to the surface of a recording medium, the secondary transfer apparatus having an endless belt as described in any one of claims 1 to 6, A transfer device equipped with the following features.

8. A toner image forming apparatus having an image holder and forming a toner image on the surface of the image holder, A transfer apparatus for transferring the toner image formed on the surface of the image holder to the surface of a recording medium, the transfer apparatus according to claim 7, An image forming apparatus equipped with the following features.

Images