Conductive roll, transfer device, process cartridge, and image forming apparatus

Abstract

To provide a conductive roll that is used to press its outer peripheral surface against a counter roll to form an insertion part into which a medium is inserted, the conductive roll excellent in separability of the medium inserted into the insertion part.SOLUTION: A conductive roll has a support member, an elastic layer that is arranged on an outer peripheral surface of the support member, an intermediate layer that is arranged on an outer peripheral surface of the elastic layer, and a surface layer that is arranged on an outer peripheral surface of the intermediate layer. The elastic layer includes a cylindrical elastic foam, and a conductive coating layer that covers an exposed surface of the elastic foam. The Young's modulus Yd of the elastic layer and the Young's modulus Ym of the intermediate layer satisfy the relationship of Yd<Ym.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a conductive roll, a transfer device, a process cartridge, and an image forming apparatus. [Background technology]

[0002] Patent Document 1 describes a semiconductive image forming member in which a semiconductive elastic layer is provided on the outer peripheral surface of a conductive substrate, and a first layer and a second layer are coated on the surface of the elastic layer in this order. The semiconductive imaging member is disclosed in which the Young's modulus of the first layer material is 1.0×10 4 (Pa)<Young's modulus of the first layer material<Young's modulus of the second layer material<1.0×10 10 (Pa). Patent Document 2 discloses a semiconductive roll used in a developing device that visualizes an electrostatic latent image formed on a latent image carrier, the semiconductive roll including a conductive shaft, at least one elastic semiconductive layer provided around the conductive shaft, and a toner carrying layer formed of a thermosetting polymer or a thermoplastic polymer and provided around the elastic semiconductive layer, carrying a thin layer of triboelectrically charged toner, the semiconductive roll having a static friction coefficient of 0.1 to 1.5 and a Young's modulus of 1 to 6,500 MPa for use in the developing device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-005505 A [Patent Document 2] JP 2004-212865 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure relates to a conductive roll used to form an insertion portion that presses an outer peripheral surface against an opposing roll and allows a medium to pass therethrough. The object is to provide a conductive roll that is excellent in the peelability of a medium passing through the insertion portion as compared with a case where the Young's modulus Yd of an elastic layer is larger than the Young's modulus of an intermediate layer. Hereinafter, "excellent in the peelability of a medium passing through the insertion portion" is also simply referred to as "excellent in the peelability of the medium". Here, examples of the medium passing through the insertion portion include paper used in electrophotographic copiers and printers described later; resin films such as OHP sheets; and in addition, displays, package sheets, and the like.

Means for Solving the Problem

[0005] Specific means for solving the above problems include the following aspects.

[0006] <1> It has a support member, an elastic layer disposed on the outer peripheral surface of the support member, an intermediate layer disposed on the outer peripheral surface of the elastic layer, and a surface layer disposed on the outer peripheral surface of the intermediate layer. The elastic layer is composed of a cylindrical elastic foam and a conductive coating layer covering the exposed surface of the elastic foam. A conductive roll in which the Young's modulus Yd of the elastic layer and the Young's modulus Ym of the intermediate layer satisfy the relationship Yd < Ym.

[0007] <2> The conductive roll according to <1>, wherein the Young's modulus Yd of the elastic layer and the Young's modulus Ym of the intermediate layer satisfy the relationship 10 ≦ Ym / Yd ≦ 100. <3> The conductive roll according to <1> or <2>, wherein the Young's modulus Yd of the elastic layer is 50 kPa or more and 500 kPa or less. <4> The conductive roll according to any one of <1> to <3>, wherein the Young's modulus Ym of the intermediate layer and the Young's modulus Ys of the surface layer satisfy the relationship Ym < Ys. <5> The conductive roll according to <4>, wherein the Young's modulus Ym of the intermediate layer and the Young's modulus Ys of the surface layer satisfy the relationship 5 ≦ Ys / Ym ≦ 100. <6> a thickness Td of the elastic layer, a thickness Tm of the intermediate layer, and a thickness Ts of the surface layer satisfy a relationship of Td>Tm>Ts and a relationship of 0.05≦Td / (Td+Tm+Ts)≦0.45; <1> ~ <5> 13. The conductive roll according to claim 12, <7> The elastic foam has an open cell structure. <1> ~ <6> 13. The conductive roll according to claim 12, <8> The density of the elastic foam is 50 kg / m 3 More than 90kg / m 3 Below is the <7> The conductive roll according to claim 1.

[0008] <9> <1> ~ <8> 2. A transfer device comprising the conductive roll according to claim 1 . <10> Image carrier and <9> and a transfer device according to claim 1, wherein the process cartridge is detachably mounted on an image forming apparatus. <11> An image carrier; a charging device for charging the surface of the image carrier; an electrostatic latent image forming device for forming an electrostatic latent image on a charged surface of the image carrier; a developing device for developing the electrostatic latent image formed on the surface of the image carrier with a developer containing a toner to form a toner image; The toner image is transferred onto a surface of a recording medium. <9> A transfer device according to the present invention; An image forming apparatus comprising: Effect of the Invention

[0009] <1> According to the invention, there is provided a conductive roll used to press the outer surface against an opposing roll to form an insertion portion through which a medium passes, the conductive roll having superior medium peelability compared to a case in which the Young's modulus Yd of the elastic layer is greater than the Young's modulus of the intermediate layer.

[0010] <2> According to the present invention, a conductive roll is provided which is excellent in medium peeling properties, as compared with a case where the relationship 10≦Ym / Yd≦100 is not satisfied. <3> According to the present invention, there is provided a conductive roll which is excellent in medium peeling properties compared to a case where the Young's modulus Yd of the elastic layer exceeds 500 kPa. <4> According to the present invention, there is provided a conductive roll which is excellent in medium peelability, as compared with a case in which the Young's modulus Ym of the intermediate layer is larger than the Young's modulus Ys of the surface layer. <5> According to the present invention, a conductive roll is provided which is excellent in medium peelability, as compared with a case where the relationship 5≦Ys / Ym≦100 is not satisfied. <6> The thickness Td of the elastic layer, the thickness Tm of the intermediate layer, and the thickness Ts of the surface layer satisfy the relationship Td>Tm>Ts, and the conductive roll is more suitable for use as a transfer roll than a roll that does not satisfy the relationship 0.05≦Td / (Td+Tm+Ts)≦0.45. <7> According to the present invention, there is provided a conductive roll which has excellent medium peeling properties compared to a case where the elastic foam has a closed cell structure. <8> According to the invention, the density of the elastic foam is 50 kg / m 3 Less than or equal to 90kg / m 3 Thus, a conductive roll having excellent medium peelability is provided as compared with a case where the conductive roll is made of a material other than a conductive material.

[0011] <9> , <10> or <11> According to the invention, there is provided a transfer device, a process cartridge, or an image forming apparatus equipped with a conductive roll which is used to press the outer surface against an opposing roll to form an insertion portion through which a medium passes, and which has superior medium peeling properties compared to a case in which the Young's modulus Yd of the elastic layer is greater than the Young's modulus of the intermediate layer. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a schematic perspective view illustrating an example of a conductive roller according to the present embodiment. [Diagram 2] 2 is a schematic cross-sectional view showing an example of a conductive roller according to the present embodiment, and is a cross-sectional view taken along the line AA in FIG. [Diagram 3] 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Figure 4] FIG. 4 is a schematic configuration diagram illustrating another example of an image forming apparatus according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present disclosure will be described. These descriptions and examples are merely illustrative of the embodiments, and are not intended to limit the scope of the embodiments.

[0014] In the present disclosure, a numerical range indicated using "~" indicates a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively.

[0015] In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.

[0016] In the present disclosure, the term "step" includes not only an independent step, but also a step that cannot be clearly distinguished from other steps, as long as the intended purpose of the step is achieved.

[0017] When an embodiment of the present disclosure is described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the size of the members in each drawing is conceptual, and the relative relationship between the sizes of the members is not limited to this.

[0018] In the present disclosure, each component may contain multiple types of corresponding substances. When referring to the amount of each component in a composition in the present disclosure, if multiple substances corresponding to each component are present in the composition, the total amount of the multiple substances present in the composition is meant unless otherwise specified.

[0019] <Conductive roll> The conductive roll according to this embodiment has a support member, an elastic layer disposed on the outer peripheral surface of the support member, an intermediate layer disposed on the outer peripheral surface of the elastic layer, and a surface layer disposed on the outer peripheral surface of the intermediate layer. The elastic layer is composed of a cylindrical elastic foam and a conductive coating layer that covers the exposed surface of the elastic foam, and the Young's modulus Yd of the elastic layer and the Young's modulus Ym of the intermediate layer satisfy the relationship Yd < Ym.

[0020] The conductive roll according to this embodiment is not particularly limited in its use as long as it is a conductive roll used to form an insertion portion for pressing the outer peripheral surface against a counter roll and inserting a recording medium. That is, the conductive roll according to this embodiment presses its outer peripheral surface against the counter roll and forms the pressing area as the insertion portion. The conductive roll according to this embodiment is preferably used, for example, as a transfer roll or a conveyance roll for a recording medium in an electrophotographic image forming apparatus. Note that the use of the conductive roll according to this embodiment is not limited to the above.

[0021] When forming an insertion portion for pressing the outer peripheral surface of the conductive roll against a counter roll and inserting a medium, the medium may be wound around the conductive roll, resulting in a decrease in the peelability of the medium from the conductive roll. Conventionally, a conductive roll is composed of, for example, a support member and an elastic layer disposed on the outer peripheral surface of the support member. When the conductive roll is pressed against a counter roll, the shape of the elastic layer deforms following the shape of the counter roll. At this time, the outer peripheral surface of the conductive roll deforms so as to wrap around the outer peripheral surface of the counter roll. Such deformation of the outer peripheral surface of the conductive roll causes the medium to wind around the conductive roll as described above. This winding of the medium around the conductive roll is more likely to occur when the medium is thinner.

[0022] In the conductive roll according to the present embodiment, an elastic layer, an intermediate layer, and a surface layer are arranged in this order on the outer peripheral surface of the support member. The elastic layer is configured to include a cylindrical elastic foam and a conductive coating layer that covers the exposed surface of the elastic foam. The Young's modulus Yd of the elastic layer and the Young's modulus Ym of the intermediate layer satisfy the relationship Yd < Ym. In the conductive roll according to the present embodiment, the elastic layer is configured to include a cylindrical elastic foam and a conductive coating layer that covers the exposed surface of the elastic foam. Such an elastic layer is imparted with the desired conductivity by the conductive coating layer, and a soft elastic layer can be obtained as compared with the case where a conductive agent is contained in the elastic foam. The conductive roll having a soft elastic layer can form an insertion portion for the medium by pressing its outer peripheral surface against the opposing roll. Further, in the conductive roll, by making the Young's modulus of the intermediate layer disposed more outward larger than the Young's modulus of the elastic layer disposed inward, when the conductive roll is pressed against the opposing roll, the outer peripheral surface of the conductive roll is deformed into a planar shape, and it becomes difficult for a deformation that follows the shape of the opposing roll to occur. That is, in the conductive roll at this time, a deformation in which the outer peripheral surface wraps around the outer peripheral surface of the opposing roll is suppressed. As a result, it is presumed that when the conductive roll according to the present embodiment is used to form an insertion portion for pressing the outer peripheral surface against the opposing roll and inserting the medium, the peelability of the medium inserted through the insertion portion can be improved.

[0023] [Preferred embodiment] In the conductive roll according to the present embodiment, from the viewpoint of excellent peelability of the medium, it is preferable that the Young's modulus Yd of the elastic layer and the Young's modulus Ym of the intermediate layer satisfy the relationship 10 ≦ Ym / Yd ≦ 100, more preferably satisfy the relationship 15 ≦ Ym / Yd ≦ 80, and still more preferably satisfy the relationship 20 ≦ Ym / Yd ≦ 70.

[0024] In the conductive roll according to the present embodiment, from the viewpoint of excellent releasability of the medium, the Young's modulus Yd of the elastic layer is preferably 50 kPa or more and 500 kPa or less, more preferably 60 kPa or more and 300 kPa or less, and still more preferably 80 kPa or more and 150 kPa or less. The above Young's modulus can be easily achieved by reducing the content of particulate matter (e.g., electronic conductive agent, filler, etc.) in the elastic foam.

[0025] In the conductive roll according to the present embodiment, from the viewpoint of further improving the releasability of the medium, it is preferable that the Young's modulus Ym of the intermediate layer and the Young's modulus Ys of the surface layer satisfy the relationship Ym < Ys. Also, for the same reason, it is preferable that the Young's modulus Ym of the intermediate layer and the Young's modulus Ys of the surface layer satisfy the relationship 5 ≤ Ys / Ym ≤ 100, more preferably satisfy the relationship 10 ≤ Ys / Ym ≤ 80, and still more preferably satisfy the relationship 15 ≤ Ys / Ym ≤ 70.

[0026] The Young's modulus of each layer is measured as follows. The measurement method of the Young's modulus of each layer basically conforms to ISO527. For the intermediate layer and the elastic layer, a dumbbell-shaped tensile test piece with a gauge length of 50 mm and a thickness of 5 mm is prepared, and the stress (σ)-strain (ε) curve at a tensile speed of 5 mm / min is obtained using a tabletop precision universal testing machine (AGS-X; manufactured by Shimadzu Corporation). The stress at a strain of 0.05% to 0.25% is measured, and the Young's modulus is obtained from Δσ / Δε. In the case of the Young's modulus of the surface layer, a dumbbell-shaped tensile test piece with a thickness of 0.2 mm is prepared, and the Young's modulus is obtained in the same manner as the measurement method of the Young's modulus of the intermediate layer and the elastic layer, except that this is used.

[0027] The conductive roll according to the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing an example of the conductive roll according to the present embodiment. FIG. 2 is a cross-sectional view taken along the line A-A of FIG. 1, and is a cross-sectional view obtained by cutting the conductive roll shown in FIG. 1 in the radial direction.

[0028] 1, the conductive roll 100 is a roll member including a cylindrical support member 110 and a layered material 120 including an elastic layer, an intermediate layer, and a surface layer, which is disposed on the outer peripheral surface of the support member 110. As shown in FIG. 2, the layer configuration of the conductive roll 100 includes an elastic layer 122 disposed on the outer peripheral surface of the cylindrical support member 110, an intermediate layer 124 disposed on the outer peripheral surface of the elastic layer 122, and a surface layer 126 disposed on the outer peripheral surface of the intermediate layer 124. The conductive roll according to this embodiment is not limited to the configuration shown in FIGS. 1 and 2, and may have, for example, an adhesive layer between the support member 110 and the elastic layer 122, between the elastic layer 122 and the intermediate layer 124, and between the intermediate layer 124 and the surface layer 126, as appropriate.

[0029] The materials of the layers constituting the conductive roll according to this embodiment will be described below.

[0030] [Support member] In the conductive roll according to this embodiment, the support member may be any member that functions as a support member for the conductive roll. The support member may be a hollow member (ie, a cylindrical member) or a solid member (ie, a columnar member). When an electric field is formed between the conductive roll and the opposing roll, the support member is preferably a conductive support member.

[0031] Examples of conductive support members include metal members such as iron (free-cutting steel, etc.), copper, brass, stainless steel, aluminum, nickel, etc.; resin members or ceramic members having plated outer surfaces; and resin members or ceramic members containing a conductive agent.

[0032] The outer diameter of the support member may be determined depending on the application of the conductive roll. For example, if the conductive roll according to this embodiment is a secondary transfer roll, the outer diameter of the support member is, for example, 3 mm or more and 30 mm or less.

[0033] [Elastic layer] In the conductive roll according to this embodiment, the elastic layer includes a cylindrical elastic foam and a conductive coating layer that covers the exposed surface of the elastic foam.

[0034] (Elastic foam) The elastic foam constituting the elastic layer is a foam containing an elastic material (also called a rubber material).

[0035] Examples of elastic materials include isoprene rubber, chloroprene rubber, epichlorohydrin rubber, butyl rubber, polyurethane, silicone rubber, fluororubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), natural rubber, and rubber mixtures of these.

[0036] Examples of blowing agents for obtaining elastic foams include water; azo compounds such as azodicarbonamide, azobisisobutyronitrile, and diazoaminobenzene; benzenesulfonyl hydrazides such as benzenesulfonyl hydrazide, 4,4'-oxybisbenzenesulfonyl hydrazide, and toluenesulfonyl hydrazide; bicarbonates such as sodium hydrogen carbonate that generate carbon dioxide gas upon thermal decomposition; a mixture of NaNO2 and NH4Cl that generates nitrogen gas; and peroxides that generate oxygen. In order to obtain a foamed elastic layer, a foaming assistant, a foam stabilizer, a catalyst, etc. may be used as necessary.

[0037] The elastic foam may contain a conductive agent from the viewpoint of controlling the electrical conductivity of the elastic layer. The conductive agent contained in the elastic foam includes an electronic conductive agent and an ionic conductive agent. In addition, from the viewpoint of setting the Young's modulus Yd of the elastic layer in the above-mentioned preferred range, the content of the conductive agent (particularly when it is an electronic conductive agent) in the elastic foam is 1 mass % or less, preferably 0.5 mass % or less, and more preferably 0 mass % or less, relative to the total mass of the elastic foam. In other words, the less electronic conductive agent there is in the elastic foam, the better. Even if the elastic foam contains conductive particles, the content of the electronic conductive agent must be 1 mass % or less relative to the total mass of the elastic foam.

[0038] Examples of electronic conductive agents include powders of carbon black such as Ketjen black and acetylene black; pyrolytic carbon and graphite; metals or alloys such as aluminum, copper, nickel, and stainless steel; conductive metal oxides such as tin oxide, indium oxide, titanium oxide, tin oxide-antimony oxide solid solution, and tin oxide-indium oxide solid solution; and insulating materials whose surfaces have been treated to make them conductive. The electronic conductive agent may be used alone or in combination of two or more kinds.

[0039] Examples of the ion conductive agent include quaternary ammonium salts (e.g., lauryl trimethyl ammonium, stearyl trimethyl ammonium, octadecyl trimethyl ammonium, dodecyl trimethyl ammonium, hexadecyl trimethyl ammonium, or modified fatty acid dimethylethyl ammonium perchlorate, chlorate, hydroboric fluoride, sulfate, ethosulfate, benzyl bromide, or benzyl chloride), aliphatic sulfonate, higher alcohol sulfate salt, higher alcohol ethylene oxide adduct sulfate salt, higher alcohol phosphate salt, higher alcohol ethylene oxide adduct phosphate salt, betaine, higher alcohol ethylene oxide, polyethylene glycol fatty acid ester, and polyhydric alcohol fatty acid ester. The ion conductive agent may be used alone or in combination of two or more kinds.

[0040] Other additives include known materials that can be added to elastomers, such as softeners, plasticizers, hardeners, vulcanizing agents, vulcanization accelerators, antioxidants, surfactants, coupling agents, and fillers (silica, calcium carbonate, etc.). In addition, if the elastic foam contains particulate matter such as the electronic conductive agent, filler, etc., the hardness of the elastic layer increases and the releasability of the medium tends to decrease. Therefore, the less particulate matter there is in the elastic foam, the better, and even if the elastic foam contains particulate matter, the total content of the particulate matter is preferably 1% by mass or less relative to the total mass of the elastic foam.

[0041] The cell structure of the elastic foam is preferably an open cell structure from the viewpoints of formability of the conductive coating layer and excellent releasability of the medium. Here, the open cell structure means a structure in which adjacent cells (that is, cells) are connected to each other, and a part of the connected cells is exposed (open) to the surface. Furthermore, the elastic foam preferably has a smaller closed cell ratio, and the closed cell ratio is preferably, for example, 50% or less (more preferably 30% or less).

[0042] From the viewpoint of the formability of the conductive coating layer and excellent medium peelability, the cell diameter (also referred to as the air bubble diameter) of the elastic foam is preferably 50 μm or more and 1000 μm or less, more preferably 100 μm or more and 800 μm or less, and even more preferably 150 μm or more and 600 μm or less.

[0043] The density of the elastic foam (also called the air bubble ratio) is set to 50 kg / m from the viewpoint of forming a conductive coating layer and from the viewpoint of excellent peelability of the medium. 3 More than 90kg / m 3 It is preferable that the thickness is less than 55 kg / m 3 More than 85kg / m 3 More preferably, it is 60 kg / m or less. 3 More than 80kg / m 3 It is even more preferable that:

[0044] Here, the cell diameter (cell diameter), expansion rate (cell rate), and closed cell rate in the elastic foam are measured as follows. First, a cross section of the elastic layer (elastic foam in the elastic layer) in the thickness direction is prepared using a razor. A total of four cross sections are prepared in parallel to the axial direction of the conductive roll and at 90° intervals in the circumferential direction. The central part of the cross section in the axial direction is photographed with a laser microscope (Keyence, VK-X200) to obtain an image. The image is analyzed with image analysis software (Media Cybernetics, Image-Pro Plus) to measure the maximum diameter and area of ​​the cells (air bubbles). In addition, when the elastic foam has an open-cell structure, the continuous state of the cells (air bubbles) is inferred from the shape of the open cells, and each continuous (connected) cell is artificially separated and the maximum diameter of the separated cell is measured. In other words, if it is inferred that the open cells are in the shape of, for example, five connected cells, the five cells are artificially separated into five and the maximum diameter of the five separated cells is measured. The cell diameter is determined by calculating the arithmetic mean of the maximum diameters of 100 randomly selected cells in the analyzed cross-sectional image, and then calculating the arithmetic mean of the four cross-sections based on the obtained value. The foaming ratio is calculated by (total area of ​​cells in the analyzed cross-sectional images) / (total area of ​​the analyzed cross-sectional images)×100. The closed cell ratio is calculated by (total area of ​​closed cells in the analyzed cross-sectional images) / (total area of ​​cells in the analyzed cross-sectional images × 100). Here, an isolated bubble is defined as a bubble that is entirely surrounded by a wall in a cross-sectional image.

[0045] The density of the elastic foam is measured as follows. Using the elastic layer (elastic foam in the elastic layer), create a cube with a razor. The larger the cube is made, the more accurate the density measurement. Next, measure the length, width, and height of the cube, calculate the volume, measure the weight, and calculate the density by dividing the weight by the volume.

[0046] - Formation of elastic foam - The method for forming the cylindrical elastic foam is not particularly limited, and any known method can be used. For example, a method includes preparing a composition containing an elastic material, a foaming agent, and other components (such as a vulcanizing agent) that are used as needed, extruding the composition into a cylindrical shape, and then heating the molded product to vulcanize and foam it, or cutting a cylindrical shape from a large foam. Alternatively, after forming a cylindrical elastic foam, a central hole for inserting a support member may be formed to obtain a cylindrical elastic foam. After the cylindrical elastic foam is obtained, the shape may be further adjusted, or post-treatment such as surface polishing may be carried out, if necessary.

[0047] (Conductive coating layer) The elastic layer is the exposed elastic foam. surface( It is preferable that the foam has a conductive coating layer that covers the surfaces that come into contact with the atmosphere, including the inner and outer circumferential surfaces and cell wall surfaces of the cylindrical elastic foam. The exposed surface of the elastic foam may be entirely or partially covered with a conductive coating layer.

[0048] The conductive coating layer is formed using a treatment liquid containing a conductive agent and a resin. Examples of the conductive agent used in the treatment liquid include electronic conductive agents and ionic conductive agents, and among these, electronic conductive agents are preferred. The conductive agent contained in the treatment liquid may be of one type or of two or more types. Here, examples of the electronic conductive agent are the same as those of the electronic conductive agent contained in the elastic foam, and preferred embodiments are also the same.

[0049] The resin used in the treatment liquid is not particularly limited as long as it is a resin capable of forming a coating layer on the exposed surface of the elastic foam, and examples thereof include acrylic resin, urethane resin, fluororesin, silicone resin, etc. These resins are preferably used as latex. Examples of the latex include the above-mentioned resin latexes, as well as natural rubber latex, butadiene rubber latex, acrylonitrile-butadiene rubber latex, acrylic rubber latex, polyurethane rubber latex, fluororubber latex, and silicone rubber latex.

[0050] The treatment liquid preferably contains a conductive agent, a resin, and water, that is, is an aqueous dispersion containing a conductive agent and a resin. The concentrations of the conductive agent and resin in the treatment liquid may be determined depending on the formability of the conductive coating layer, the resistance value required for the elastic layer, and the like.

[0051] - Formation of conductive coating layer - The conductive coating layer is formed by applying a treatment liquid to the elastic foam and drying it by heating. Methods for applying the treatment liquid to the elastic foam include a method of applying the treatment liquid to the elastic foam by spray coating or the like, and a method of immersing the elastic foam in the treatment liquid. By these methods, the treatment liquid is impregnated into the surface and the inside of the cells of the elastic foam. The applied treatment liquid is then dried by heating or the like to form a conductive coating layer.

[0052] As the conductive coating layer, for example, the coating layer and the method for forming the same described in JP-A-2009-244824 may be used.

[0053] As described above, the conductive coating layer is formed on the exposed surface of the elastic foam, thereby forming the elastic layer in the conductive roll according to the present embodiment.

[0054] (Volume resistance of elastic layer) In the conductive roll according to this embodiment, the volume resistance of the elastic layer when a voltage of 10 V is applied is 10 5 It is preferable that the resistance is 10 Ω or less. 1 Ω or more 10 5 More preferably, it is 10 2 Ω or more 10 4 It is more preferable that the resistance is Ω or less.

[0055] The volume resistance values ​​of the elastic layer and the laminated roll such as the conductive roll according to this embodiment are measured as follows. The elastic layer is first prepared by preparing a roll member having an elastic layer to be measured on the outer periphery of a conductive support member, and the volume resistance value of the elastic layer is measured using the obtained roll member. In addition, when the conductive roll according to the present embodiment has a conductive support member, the roll member obtained by peeling off the intermediate layer and the surface layer from the conductive roll may be measured. The roll member is placed on a metal plate such as a copper plate with a load of 500 g applied to each end of the roll member, and a voltage (V) of 10 V (in the case of an elastic layer) is applied between the conductive support member of the roll member and the metal plate using a microcurrent meter (R8320 manufactured by Advantest). The current value I (A) after 5 seconds is read and calculated using the following formula. Formula: Volume resistance Rv(Ω)=V / I The measurements are carried out in an environment with a temperature of 22°C and a humidity of 55% RH.

[0056] In addition, the volume resistivity of a laminated roll having an intermediate layer and a surface layer in addition to the elastic layer is measured in the same manner as that of the elastic layer, except that a voltage of 1000 V is applied to the laminated roll.

[0057] The volume resistivity of the intermediate layer and the surface layer is measured in accordance with JIS K 6911 as follows. First, a sheet member is prepared using the layer material, and the volume resistivity is measured using the obtained sheet member. The appropriate thickness of the sheet member is 1 mm for the intermediate layer and 0.2 mm for the surface layer. The sheet member is placed between the circular electrodes, and a microcurrent meter (Advantest R8320) is used to apply a voltage (V) of 100 V to the intermediate layer and 50 V to the surface layer between the front and back electrodes. The current value I (A) after 5 seconds is read and calculated using the following formula. Formula: Volume resistance Rv(Ω)=V / I The measurements are carried out in an environment with a temperature of 22°C and a humidity of 55% RH.

[0058] (Elastic layer thickness) In the conductive roll according to this embodiment, the thickness of the elastic layer may be determined depending on the application of the conductive roll. For example, when the conductive roll according to the present embodiment is a secondary transfer roll, the thickness of the elastic layer is, for example, 1 mm or more and 10 mm or less.

[0059] In addition, in the conductive roll according to the present embodiment, from the viewpoint of applicability to a transfer roll, it is preferable that the thickness Td of the elastic layer, the thickness Tm of the intermediate layer, and the thickness Ts of the surface layer satisfy the relationship Td>Tm>Ts and the relationship 0.05≦Td / (Td+Tm+Ts)≦0.45, and more preferably the relationship 0.10≦Td / (Td+Tm+Ts)≦0.25.

[0060] [Middle layer] The intermediate layer is a layer disposed on the outer peripheral surface of the elastic layer. The intermediate layer is a layer that contributes to adjusting the resistance of the conductive roll, and the volume resistance of the intermediate layer when a voltage of 100 V is applied is 10 4 Ω or more 10 9 Ω or less (preferably 10 6 Ω or more 10 9 Ω or less). The volume resistivity of the intermediate layer is measured in the same manner as the volume resistivity of the elastic layer.

[0061] In order to achieve the above volume resistivity, the intermediate layer preferably contains a conductive agent. As the conductive agent, either an electronic conductive agent or an ionic conductive agent can be used. Among them, it is preferable to use an ionic conductive agent from the viewpoint of improving the charge retention. That is, the intermediate layer preferably contains an ionic conductive agent. The ionic conductive agent contained in the intermediate layer may be the same as the ionic conductive agent contained in the elastic foam, and the preferred embodiments are also the same. The ion conductive agent may be used alone or in combination of two or more kinds.

[0062] The ionic conductive agent used in the intermediate layer may be a polymeric material having ionic conductivity, such as epichlorohydrin rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer rubber, or the like. The ionic conductive agent used in the intermediate layer may be a compound in which an ionic conductive agent is bonded to the end of a polymer material such as a resin.

[0063] The content of the ion conductive agent may be within a range that allows the above-mentioned volume resistivity to be achieved. When the intermediate layer contains a binder material, the content of the ion conductive agent is preferably 0.1 to 5.0 parts by mass, more preferably 0.5 to 3.0 parts by mass, per 100 parts by mass of the binder material.

[0064] The intermediate layer may contain a binder material in addition to the ion conductive agent. The binder material is not particularly limited, and examples thereof include resins capable of forming an intermediate layer, elastic materials, etc. Examples of resins used in the intermediate layer include urethane resins, acrylic resins, epoxy resins, silicone resins, etc. In addition, the elastic material contained in the intermediate layer is the same as the elastic material used in the elastic layer.

[0065] The intermediate layer may contain other additives depending on the physical properties required for the intermediate layer.

[0066] (Young's modulus of the middle layer) The Young's modulus of the intermediate layer is preferably 5 MPa or more, and more preferably 5 MPa or more and 10 MPa or less. The Young's modulus of the intermediate layer is measured in the same manner as that of the elastic layer.

[0067] (Thickness of middle layer) In the conductive roll according to this embodiment, the thickness of the intermediate layer may be determined depending on the application of the conductive roll, and is preferably thinner than the elastic layer. For example, when the conductive roll according to the present embodiment is a secondary transfer roll, the thickness of the intermediate layer is, for example, 0.5 mm or more and 5 mm or less.

[0068] The method for forming the intermediate layer is not particularly limited, and for example, a method of applying a coating liquid for forming the intermediate layer onto the elastic layer and drying the resulting coating film can be mentioned.

[0069] [Surface layer] The surface layer is a layer disposed on the outer peripheral surface of the intermediate layer, and is a layer that constitutes the outermost surface of the conductive roll. Since the surface layer comes into contact with the medium, it is preferable that the surface layer has releasability.

[0070] The surface layer is preferably a layer containing a resin. The resin contained in the surface layer is not particularly limited, but examples thereof include urethane resin, polyester resin, phenol resin, acrylic resin, epoxy resin, and cellulose resin.

[0071] The surface layer preferably contains a conductive agent. The conductive agent contained in the surface layer includes an electronic conductive agent and an ionic conductive agent. The electronic conductive agent contained in the surface layer is the same as the electronic conductive agent used in the conductive coating layer, and the ionic conductive agent contained in the surface layer is the same as the ionic conductive agent used in the intermediate layer.

[0072] The surface layer may contain other additives depending on the physical properties required for the surface layer.

[0073] (Young's modulus of surface layer) The Young's modulus of the surface layer is preferably 50 MPa or more, and more preferably 50 MPa or more and 400 MPa or less. The Young's modulus of the surface layer is measured in the same manner as that of the elastic layer.

[0074] (Surface layer thickness) In the conductive roll according to this embodiment, the thickness of the surface layer may be determined depending on the application of the conductive roll. For example, when the conductive roll according to the present embodiment is a secondary transfer roll, the thickness of the surface layer is, for example, 0.01 mm or more and 0.05 mm or less.

[0075] (Volume resistivity of surface layer) The volume resistance of the surface layer when a voltage of 50 V is applied is 10 4 Ω or more 10 14 It is preferable that the resistance is 10 Ω or less. 6 Ω or more 10 12 It is more preferable that it is Ω or less. The volume resistivity of the surface layer is measured in the same manner as the volume resistivity of the elastic layer.

[0076] The method for forming the surface layer is not particularly limited, and for example, a method of applying a coating liquid for forming the surface layer onto the intermediate layer and drying the resulting coating film can be mentioned.

[0077] [Volume resistance of conductive roll] The conductive roll according to the present embodiment has a volume resistance of 10 4 Ω or more 10 12 It is preferable that the resistance is 10 Ω or less. 5 Ω or more 10 11 More preferably, it is 10 6 Ω or more 10 10 It is more preferable that the resistance is Ω or less. The volume resistivity of the conductive roll is measured in the same manner as the volume resistivity of the elastic layer.

[0078] <Image forming devices, transfer devices, process cartridges> FIG. 3 is a schematic diagram showing the configuration of a direct transfer type image forming apparatus, which is an example of the image forming apparatus according to the present embodiment.

[0079] The image forming apparatus 200 shown in FIG. 3 includes a photoconductor 207 (an example of an image carrier), a charging roll 208 (an example of a charging means) that charges the surface of the photoconductor 207, an exposure device 206 (an example of an electrostatic image forming means) that forms an electrostatic image on the charged surface of the photoconductor 207, a developing device 211 (an example of a developing means) that develops the electrostatic image formed on the surface of the photoconductor 207 into a toner image using a developer containing toner, and a transfer roll 212 (an example of a transfer means, an example of a transfer device according to this embodiment) that transfers the toner image formed on the surface of the photoconductor 207 to the surface of a recording medium. Here, the conductive roll according to this embodiment is applied to a transfer roll 212 which presses its outer peripheral surface against a photoconductor 207 which corresponds to an opposing roll and forms an insertion portion through which a recording paper 500 passes.

[0080] The image forming apparatus 200 shown in FIG. 3 further includes a cleaning device 213 that removes toner remaining on the surface of the photoconductor 207, a discharge device 214 that discharges electricity from the surface of the photoconductor 207, and a fixing device 215 (an example of a fixing means) that fixes the toner image to a recording medium.

[0081] The charging roll 208 may be of a contact charging type or a non-contact charging type. A voltage is applied to the charging roll 208 from a power source 209.

[0082] The exposure device 206 may be an optical device equipped with a light source such as a semiconductor laser or an LED (light emitting diode).

[0083] The developing device 211 is a device that supplies toner to the photoconductor 207. The developing device 211, for example, brings a roll-shaped developer holder into contact with or close to the photoconductor 207 and causes the toner to adhere to the electrostatic charge image on the photoconductor 207, thereby forming a toner image.

[0084] The transfer roll 212 is a transfer roll that directly contacts the surface of the recording medium, and is disposed at a position facing the photoreceptor 207. Recording paper 500 (an example of a recording medium) is supplied to the gap where the transfer roll 212 and the photoreceptor 207 are in contact with each other via a supply mechanism. When a transfer bias is applied to the transfer roll 212, an electrostatic force from the photoreceptor 207 to the recording paper 500 acts on the toner image, and the toner image on the photoreceptor 207 is transferred onto the recording paper 500.

[0085] The fixing device 215 may be, for example, a heat fixing device including a heating roll and a pressure roll that presses against the heating roll.

[0086] The cleaning device 213 may be a device equipped with a blade, a brush, a roll, or the like as a cleaning member.

[0087] The static eliminator 214 is a device that irradiates the surface of the photoconductor 207 with light after transfer, thereby eliminating the residual potential of the photoconductor 207.

[0088] The photoconductor 207 and the transfer roll 212 may be integrated into a single housing, for example, to form a cartridge structure (the process cartridge according to the present embodiment) that is detachably attached to the image forming apparatus. The cartridge structure (the process cartridge according to the present embodiment) may further include at least one selected from the group consisting of a charging roll 208, an exposure device 206, a developing device 211, and a cleaning device 213.

[0089] The image forming apparatus may be a tandem type image forming apparatus in which a photoconductor 207, a charging roll 208, an exposure device 206, a developing device 211, a transfer roll 212 and a cleaning device 213 are configured as one image forming unit, and multiple such image forming units are mounted side by side.

[0090] Fig. 4 is a schematic diagram showing an intermediate transfer type image forming apparatus, which is an example of the image forming apparatus according to the present embodiment. The image forming apparatus shown in Fig. 4 is a tandem type image forming apparatus in which four image forming units are arranged in parallel.

[0091] In the image forming apparatus shown in Fig. 4, a transfer unit that transfers a toner image formed on the surface of an image carrier to the surface of a recording medium is configured as a transfer unit (an example of a transfer device according to the present embodiment) that includes an intermediate transfer body, a primary transfer unit, and a secondary transfer unit. The transfer unit may have a cartridge structure that is detachably attached to the image forming apparatus.

[0092] The image forming apparatus shown in FIG. 4 includes a photoconductor 1 (an example of an image carrier), a charging roll 2 (an example of a charging means) that charges the surface of the photoconductor 1, an exposure device 3 (an example of an electrostatic image forming means) that forms an electrostatic image on the charged surface of the photoconductor 1, a developing device 4 (an example of a developing means) that develops the electrostatic image formed on the surface of the photoconductor 1 into a toner image using a developer containing toner, an intermediate transfer belt 20 (an example of an intermediate transfer body), a primary transfer roll 5 (an example of a primary transfer means) that transfers the toner image formed on the surface of the photoconductor 1 to the surface of the intermediate transfer belt 20, and a secondary transfer roll 26 (an example of a secondary transfer means) that transfers the toner image transferred to the surface of the intermediate transfer belt 20 to the surface of a recording medium. Here, the conductive roll according to this embodiment is applied to the secondary transfer roll 26, which presses its outer peripheral surface against the support roll 27, which corresponds to the opposing roll, and forms an insertion portion through which the recording paper P passes.

[0093] The image forming apparatus shown in FIG. 4 further includes a fixing device 28 (an example of a fixing means) that fixes the toner image onto a recording medium, a photoreceptor cleaning device 6 that removes toner remaining on the surface of the photoreceptor 1, and an intermediate transfer belt cleaning device 30 that removes toner remaining on the surface of the intermediate transfer belt 20.

[0094] The image forming apparatus shown in Fig. 4 includes first to fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K that output images in the colors of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units 10Y, 10M, 10C, and 10K are arranged side by side and spaced apart from each other in the horizontal direction. Each of the image forming units 10Y, 10M, 10C, and 10K may be a process cartridge that is detachably attached to the image forming apparatus.

[0095] Above each of the image forming units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 is provided to extend through each of the image forming units. The intermediate transfer belt 20 is provided wound around a drive roll 22 and a support roll 24 that are in contact with the inner surface of the intermediate transfer belt 20, and runs in a direction from the first image forming unit 10Y to the fourth image forming unit 10K. A force is applied to the support roll 24 by a spring or the like (not shown) in a direction away from the drive roll 22, and tension is applied to the intermediate transfer belt 20 wound around them. An intermediate transfer belt cleaning device 30 is provided on the image bearing surface side of the intermediate transfer belt 20, facing the drive roll 22.

[0096] The developing devices 4Y, 4M, 4C, and 4K of the image forming units 10Y, 10M, 10C, and 10K are supplied with yellow, magenta, cyan, and black toners contained in toner cartridges 8Y, 8M, 8C, and 8K, respectively.

[0097] Since the first to fourth image forming units 10Y, 10M, 10C, and 10K have the same configuration and operation, in the following description of the image forming units, the first image forming unit 10Y will be representatively described.

[0098] The first image forming unit 10Y includes a photoconductor 1Y, a charging roll 2Y that charges the surface of the photoconductor 1Y, a developing device 4Y that develops the electrostatic charge image formed on the surface of the photoconductor 1Y into a toner image using a developer containing toner, a primary transfer roll 5Y that transfers the toner image formed on the surface of the photoconductor 1Y to the surface of the intermediate transfer belt 20, and a photoconductor cleaning device 6Y that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer.

[0099] The charging roll 2Y charges the surface of the photoreceptor 1Y. The charging roll 2Y may be of a contact charging type or a non-contact charging type.

[0100] The charged surface of the photoconductor 1Y is irradiated with a laser beam 3Y from the exposure device 3. As a result, an electrostatic charge image of a yellow image pattern is formed on the surface of the photoconductor 1Y.

[0101] The developing device 4Y contains an electrostatic image developer that contains at least yellow toner and a carrier. The yellow toner is triboelectrically charged by being stirred inside the developing device 4Y. As the surface of the photoconductor 1Y passes through the developing device 4Y, the electrostatic image formed on the photoconductor 1Y is developed into a toner image.

[0102] The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20, facing the photoconductor 1Y. A bias power supply (not shown) that applies a primary transfer bias is connected to the primary transfer roll 5Y. The primary transfer roll 5Y transfers the toner image on the photoconductor 1Y onto the intermediate transfer belt 20 by electrostatic force.

[0103] The toner images of each color are transferred in multiple layers onto the intermediate transfer belt 20 from the first to fourth image forming units 10Y, 10M, 10C, and 10K in this order. The intermediate transfer belt 20 onto which the toner images of the four colors have been multiple-transferred through the first to fourth image forming units reaches a secondary transfer means composed of a support roll 24 and a secondary transfer roll 26.

[0104] The secondary transfer roll 26 is a transfer roll that is in direct contact with the surface of the recording medium, and is disposed at a position facing the support roll 24 on the outer side of the intermediate transfer belt 20. Recording paper P (an example of a recording medium) is supplied to the gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact with each other via a supply mechanism. When a secondary transfer bias is applied to the secondary transfer roll 26, an electrostatic force directed from the intermediate transfer belt 20 to the recording paper P acts on the toner image, and the toner image on the intermediate transfer belt 20 is transferred onto the recording paper P.

[0105] The recording paper P onto which the toner image has been transferred is sent into a pressure contact portion (nip portion) of a fixing device 28 consisting of a pair of rolls, where the toner image is fixed onto the recording paper P.

[0106] The toner and developer used in the image forming apparatus according to the present embodiment are not particularly limited, and any known toner and developer for electrophotography can be used. The recording medium used in the image forming apparatus according to this embodiment is not particularly limited, and examples thereof include paper used in electrophotographic copying machines and printers; OHP sheets; and the like. EXAMPLES

[0107] Hereinafter, the embodiments of the present invention will be described in detail with reference to examples, but the embodiments of the present invention are not limited to these examples. In the text, "parts" means "parts by mass" unless otherwise specified.

[0108] <Example 1> [Formation of elastic layer] (Formation of Elastic Foam) EP70 (manufactured by Inoac Corporation) was used as the elastic foam, and cut into a cylindrical shape with an outer diameter of 26 mm and an inner diameter of 14 mm to obtain a cylindrical elastic foam. The obtained elastic foam has an open cell structure, a cell diameter of 400 μm, and a density of 70 kg / m 3 It was.

[0109] (Formation of conductive coating layer) The elastic foam obtained by the above method was immersed for 10 minutes at 20°C in a treatment liquid prepared by mixing an aqueous dispersion containing 36 mass% carbon black and an acrylic emulsion (manufactured by Zeon Corporation, product name "Nipol LX852") in a mass ratio of 1:1. The elastic foam with the treatment liquid attached was then heated and dried for 60 minutes in a curing oven set at 100°C to remove moisture and crosslink the acrylic resin. A conductive coating layer containing carbon black was formed on the exposed surface of the elastic foam by the acrylic resin hardened by crosslinking. In this manner, an elastic layer composed of an elastic foam and a conductive coating layer covering the exposed surface of the elastic foam was obtained. Next, a conductive supporting member (made of SUS, diameter 14 mm) having an adhesive applied to its surface was inserted into the obtained elastic layer to form a roll member.

[0110] [Formation of intermediate layer] A coating solution for forming an intermediate layer was obtained by mixing 70 parts of a urethane oligomer (Urethane Acrylate UV3700B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 30 parts of a urethane monomer (Isomyristyl Acrylate, manufactured by Kyoeisha Chemical Co., Ltd.), 0.5 parts of a polymerization initiator (1-hydroxycyclohexyl phenyl ketone Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.), and 3 parts of an alkyl trimethyl ammonium perchlorate (product name "LXN-30", manufactured by Daiso Co., Ltd.). The obtained coating solution for forming an intermediate layer was applied onto the elastic layer using a die coater, and the coating solution was rotated at a UV irradiation intensity of 700 mW / cm. 2 The coating was then irradiated with UV light for 5 seconds. This process formed a 1 mm thick intermediate layer.

[0111] [Formation of surface layer] Next, 5% by mass of a curing agent (WH-1, manufactured by Henkel Japan Co., Ltd.) was added to a urethane resin coating (EMRALON T-862A, manufactured by Henkel Japan Co., Ltd.) and mixed to obtain a coating liquid for forming a surface layer. The obtained coating liquid for forming a surface layer was applied onto the intermediate layer by spray coating, and the coating film was heat-cured at 120°C for 20 minutes to form a surface layer with a thickness of 20 μm.

[0112] In this way, the volume resistivity was 10 6.8 Ω (measured when 1000 V was applied) of conductive roll was obtained.

[0113] <Example 2> An electrically conductive roll was obtained in the same manner as in Example 1, except that, as the elastic foam, a product having a center tolerance of RR90 (manufactured by Inoac Corporation) was used instead of EP70.

[0114] <Example 3> A conductive roll was obtained in the same manner as in Example 1, except that a high-density product of RR90 (manufactured by Inoac Corporation) was used as the elastic foam instead of EP70, and the amount of urethane monomer in the coating liquid for forming the intermediate layer was 50 parts.

[0115] <Example 4> A conductive roll was obtained in the same manner as in Example 1, except that a high-density elastic foam RR90 (manufactured by Inoac Corporation) was used instead of EP70, and the amount of urethane monomer in the coating liquid for forming the intermediate layer was 40 parts.

[0116] <Example 5> A conductive roll was obtained in the same manner as in Example 1, except that RMM (manufactured by Inoac Corporation) was used as the elastic foam instead of EP70, and the amount of urethane oligomer in the coating liquid for forming the intermediate layer was 80 parts.

[0117] <Example 6> A conductive roll was obtained in the same manner as in Example 1, except that RMM (manufactured by Inoac Corporation) was used as the elastic foam instead of EP70, and the amount of urethane oligomer in the intermediate layer was 90 parts.

[0118] <Example 7> A conductive roll was obtained in the same manner as in Example 1, except that the urethane resin coating material in the surface layer forming coating solution was changed from EMRALON T-862A to UW-1527F (manufactured by Ube Industries, Ltd.).

[0119] <Example 8> A conductive roll was obtained in the same manner as in Example 1, except that EMRALON T-862A to ST053D (manufactured by Ube Industries, Ltd.) was used as the urethane resin coating material in the surface layer forming coating liquid.

[0120] <Example 9> A conductive roll was obtained in the same manner as in Example 1, except that the urethane resin coating in the surface layer forming coating liquid was changed from EMRALON T-862A to UW5502 (manufactured by Ube Industries, Ltd.).

[0121] <Example 10> A conductive roll was obtained in the same manner as in Example 1, except that the urethane resin coating in the surface layer forming coating liquid was changed from EMRALON T-862A to UW5002E (manufactured by Ube Industries).

[0122] <Example 11> A conductive roll was obtained in the same manner as in Example 1, except that RR26 (manufactured by Inoac Corporation) was used as the elastic foam instead of EP70.

[0123] <Example 12> A conductive roll was obtained in the same manner as in Example 1, except that RMM (manufactured by Inoac Corporation) was used as the elastic foam instead of EP70.

[0124] <Example 13> A conductive roll was obtained in the same manner as in Example 1, except that, as the foam for the elastic layer, RR90 (manufactured by Inoac Corporation) with an upper tolerance limit was used instead of EP70.

[0125] <Comparative Example 1> A conductive roll was obtained in the same manner as in Example 1, except that no conductive coating layer was formed, and an RMM (manufactured by Inoac Corporation) was cut into a cylindrical shape and inserted to form an intermediate layer.

[0126] [evaluation] (Paper peelability) A paper passing bench was prepared using a secondary transfer unit of ApeosPort-VII C7788 manufactured by Fuji Xerox Co., Ltd., and the peelability was evaluated when 52 gsm paper was passed through it. · G1 (◯): The paper does not wrap around the conductive roll or intermediate transfer belt, and the paper has good peelability from the conductive roll. G2 (△): Although there was a small amount of paper wrapping around the conductive roll or intermediate transfer belt, the number of paper jams was better than G3. G3(×): The paper gets wrapped around the conductive roll or intermediate transfer belt, causing a paper jam for all units.

[0127] [Table 1]

[0128] As is clear from Table 1, the use of the conductive rolls of the Examples provides superior paper peelability compared to the use of the conductive rolls of the Comparative Examples. [Explanation of symbols]

[0129] 100 conductive roll, 110 support member, 122 elastic layer, 124 intermediate layer, 126 surface layer, 200 image forming apparatus, 206 exposure device, 207 photoconductor, 208 charging roll, 209 power source, 211 developing device, 212 transfer roll, 213 cleaning device, 214 charge removal device, 215 fixing device, 500 recording paper 1Y, 1M, 1C, 1K photoconductor, 2Y, 2M, 2C, 2K charging roll, 3 exposure device, 3Y, 3M, 3C, 3K laser beam, 4Y, 4M, 4C, 4K developing device, 5Y, 5M, 5C, 5K primary transfer roll, 6Y, 6M, 6C, 6K photoconductor cleaning device, 8Y, 8M, 8C, 8K toner cartridge, 10Y, 10M, 10C, 10K Image forming unit, 20 intermediate transfer belt, 22 drive roll, 24 support roll, 26 secondary transfer roll, 28 fixing device, 30 intermediate transfer belt cleaning device, P recording paper

Claims

1. a support member, an elastic layer disposed on an outer peripheral surface of the support member, an intermediate layer disposed on the outer peripheral surface of the elastic layer, and a surface layer disposed on the outer peripheral surface of the intermediate layer; the elastic layer includes a cylindrical elastic foam and a conductive coating layer that covers a part or all of an inner peripheral surface, an outer peripheral surface, and a cell wall surface of the cylindrical elastic foam; A conductive roll, wherein a Young's modulus Yd of the elastic layer and a Young's modulus Ym of the intermediate layer satisfy the relationship Yd<Ym.

2. The conductive roll according to claim 1 , wherein a Young's modulus Yd of the elastic layer and a Young's modulus Ym of the intermediate layer satisfy the relationship: 10≦Ym / Yd≦100.

3. 3. The conductive roll according to claim 1, wherein the elastic layer has a Young's modulus Yd of 50 kPa or more and 500 kPa or less.

4. 4. The conductive roll according to claim 1, wherein a Young's modulus Ym of the intermediate layer and a Young's modulus Ys of the surface layer satisfy the relationship Ym<Ys.

5. 5. The conductive roll according to claim 4, wherein a Young's modulus Ym of the intermediate layer and a Young's modulus Ys of the surface layer satisfy the relationship: 5≦Ys / Ym≦100.

6. 6. The conductive roll according to claim 1, wherein a thickness Td of the elastic layer, a thickness Tm of the intermediate layer, and a thickness Ts of the surface layer satisfy a relationship of Td>Tm>Ts and a relationship of 0.05≦Td / (Td+Tm+Ts)≦0.

45.

7. The conductive roll according to any one of claims 1 to 6, wherein the cylindrical elastic foam has an open-cell structure.

8. The density of the cylindrical elastic foam is 50 kg / m ３ More than 90kg / m ３ The conductive roll according to claim 7, wherein:

9. A transfer device comprising the conductive roll according to any one of claims 1 to 8.

10. A process cartridge comprising an image carrier and the transfer device according to claim 9, which is detachably mountable to an image forming apparatus.

11. An image carrier; a charging device for charging the surface of the image carrier; an electrostatic latent image forming device for forming an electrostatic latent image on a charged surface of the image carrier; a developing device for developing the electrostatic latent image formed on the surface of the image carrier with a developer containing a toner to form a toner image; a transfer device according to claim 9 for transferring the toner image onto a surface of a recording medium; An image forming apparatus comprising:

Images