Conductive roll for electronic photography device

Abstract

To provide a conductive roll for an electrophotographic apparatus in which corrosion of a core metal is suppressed by using an additive component having excellent compatibility with rubber of an elastic body layer and suppressing influence of conductivity and hardness in the elastic body layer.SOLUTION: The electrophotographic roller includes at least a metal shaft 12 and an elastic layer 14 disposed outside the outer peripheral surface of the shaft 12, and the elastic layer 14 contains a polymer containing a halogen atom, an ion conductive agent, and a compound having an epoxy group and an ester group. The content of the ion conductive agent is 0.2 parts by mass or more and 6.5 parts by mass or less with respect to 100 parts by mass of the halogen atom-containing polymer, the content of the compound having a polyoxyalkylene group and an ester group is 15 parts by mass or more and 43 parts by mass or less with respect to 100 parts by mass of the halogen atom-containing polymer, and the compound having an epoxy group and an ester group does not have an aromatic ring in the molecular structure.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a conductive roll for electrophotographic equipment that is suitably used in electrophotographic equipment such as copying machines, printers, and facsimiles that employ an electrophotographic system. [Background technology]

[0002] Electrophotographic devices such as copiers, printers, and facsimiles that employ electrophotography typically incorporate a photosensitive drum, around which are arranged roll-shaped conductive members such as a charging roll, a developing roll, a transfer roll, and a toner supply roll, as well as dirt removal members such as a cleaning blade, and belt-shaped conductive members such as a transfer belt and a fixing belt. Copying and printing using this type of electrophotographic device is performed by forming an original image as an electrostatic latent image on the photosensitive drum, adhering toner to the electrostatic latent image to form a toner image, and transferring the toner image to copy paper.

[0003] Conductive rolls for electrophotographic devices are known to have a shaft composed of a core or other material, an elastic layer formed on the outer surface of the shaft, and a surface layer formed on the outer surface of the elastic layer. Conductive rolls are molded using mold molding or assembly molding. In mold molding, the rubber in the elastic layer is tightly attached to the core by utilizing the contraction of the rubber during vulcanization. In assembly molding, hollow rubber with an inner diameter smaller than the core diameter is extruded and assembled in a later process. Conductive rolls are sometimes bonded using adhesives to ensure tight adhesion between the core and the rubber in the elastic layer. Hydrin rubber is sometimes used as the rubber material for the elastic layer of conductive rolls to reduce resistance. Ionic conductive agents are also sometimes used as conductive agents. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7319907 Summary of the Invention [Problem to be solved by the invention]

[0005] When hydrin rubber is used in the elastic layer of a conductive roll, chlorine atoms may be liberated from the hydrin rubber and react with the moisture in the rubber to generate hydrochloric acid. If the generated hydrochloric acid reaches pinholes on the core, the core corrodes. Corrosion of the core can cause changes in the roll shape and resistance, potentially resulting in image defects. Acid acceptors such as hydrotalcite are sometimes added to the elastic layer, but filler-based acid acceptors have limited dispersion in the rubber of the elastic layer, preventing them from achieving a uniform acid-accepting effect. Furthermore, adding a large amount of filler-based acid acceptor can increase the resistance and hardness of the elastic layer.

[0006] The problem to be solved by the present invention is to provide a conductive roll for electrophotographic equipment in which corrosion of the core metal is suppressed by using an additive component in the elastic layer that has excellent compatibility with the rubber of the elastic layer and that suppresses the influence of the elastic layer on conductivity and hardness. [Means for solving the problem]

[0007] The conductive roll for electrophotographic equipment according to the present invention comprises at least a metal shaft and an elastic layer disposed on the outer circumferential surface of the shaft, the elastic layer containing a polymer containing halogen atoms, an ionic conductive agent, and a compound having an epoxy group and an ester group, the content of the ionic conductive agent being 0.2 parts by mass or more and 6.5 parts by mass or less relative to 100 parts by mass of the polymer containing halogen atoms, the content of the compound having an epoxy group and an ester group being 15 parts by mass or more and 43 parts by mass or less relative to 100 parts by mass of the polymer containing halogen atoms, and the compound having an epoxy group and an ester group not having an aromatic ring in its molecular structure.

[0008] The polymer containing halogen atoms may be hydrin rubber. The weight-average molecular weight Mw of the compound having an epoxy group and an ester group may be 5,000 or more and 150,000 or less. The ionic conductive agent may be composed of one or more of sulfonium salts, ammonium salts, phosphonium salts, and imidazolium salts. The shaft body and the elastic layer may be bonded via an adhesive layer. Alternatively, the shaft body and the elastic layer may be bonded directly.

[0009] (1) The conductive roll for electrophotographic equipment according to the present invention comprises at least a metal shaft and an elastic layer disposed on the outer circumferential surface of the shaft, the elastic layer containing a polymer containing a halogen atom, an ionic conductive agent, and a compound having an epoxy group and an ester group, the content of the ionic conductive agent being 0.2 parts by mass or more and 6.5 parts by mass or less per 100 parts by mass of the polymer containing a halogen atom, the content of the compound having an epoxy group and an ester group being 15 parts by mass or more and 43 parts by mass or less per 100 parts by mass of the polymer containing a halogen atom, and the compound having an epoxy group and an ester group not having an aromatic ring in its molecular structure.

[0010] (2) In the above (1), the polymer containing halogen atoms may be a hydrin rubber.

[0011] (3) In the above (1) or (2), the weight-average molecular weight Mw of the compound having an epoxy group and an ester group may be 5,000 or more and 150,000 or less.

[0012] (4) In any one of the above (1) to (3), the ion conductive agent may be composed of one or more of sulfonium salts, ammonium salts, phosphonium salts, and imidazolium salts.

[0013] (5) In any one of the above (1) to (4), the shaft body and the elastic layer may be bonded via an adhesive layer.

[0014] (6) In any one of the above (1) to (4), the shaft body and the elastic layer may be directly bonded to each other. [Effects of the Invention]

[0015] The conductive roll for electrophotographic devices according to the present invention comprises at least a metal shaft and an elastic layer disposed on the outer circumferential surface of the shaft, the elastic layer comprising a polymer containing a halogen atom, an ionic conductive agent, and a compound having an epoxy group and an ester group. The compound having an epoxy group and an ester group captures acid originating from halogen atoms, thereby preventing the acid from reaching the metal shaft. The high content of the compound having an epoxy group and an ester group results in excellent corrosion prevention. The content of the compound having an epoxy group and an ester group is 43 parts by mass or less per 100 parts by mass of the polymer containing a halogen atom, thereby minimizing the effects of the compound on the conductivity and hardness of the elastic layer. Although the content of the compound having an epoxy group and an ester group is high, the compound having an epoxy group and an ester group does not have an aromatic ring in its molecular structure, resulting in excellent compatibility with the rubber of the elastic layer.

[0016] When the polymer containing halogen atoms is a hydrin rubber, chlorine atoms are liberated from the hydrin rubber, which tends to cause core metal corrosion. However, even in this case, the core metal corrosion is suppressed, and image defects due to core metal corrosion are suppressed.

[0017] When the weight-average molecular weight Mw of the compound having an epoxy group and an ester group is 5,000 or more and 150,000 or less, the influence of the compound on bleeding is easily suppressed, and the influence of the compound on the hardness of the elastic layer is also easily suppressed.

[0018] Furthermore, even if the ionic conductive agent is composed of one or more of sulfonium salts, ammonium salts, phosphonium salts, and imidazolium salts, the content of the compound having an epoxy group and an ester group is high, so that core metal corrosion is suppressed and image defects caused by core metal corrosion are suppressed.

[0019] Furthermore, since the compound having the epoxy group and the ester group is contained in the elastic layer, whether the shaft body and the elastic layer are bonded via an adhesive layer or directly, the effect of capturing acids resulting from halogen atoms is excellent, and therefore the corrosion prevention effect is excellent. [Brief explanation of the drawings]

[0020] [Figure 1] 1A is a schematic external view of a conductive roller for electrophotographic equipment according to one embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA thereof. [Figure 2] 1A is a schematic view of the appearance of a conductive roller for electrophotographic equipment according to another embodiment of the present invention, and FIG. 1B is a cross-sectional view thereof taken along line BB. DETAILED DESCRIPTION OF THE INVENTION

[0021] The conductive roll for electrophotographic equipment (hereinafter sometimes simply referred to as conductive roll) according to the present invention will be described in detail. Fig. 1 shows a schematic external view (a) of the conductive roll for electrophotographic equipment according to one embodiment of the present invention, and a cross-sectional view (b) of the same taken along line AA. The conductive roll includes at least a metal shaft and an elastic layer disposed on the outer circumferential surface of the shaft.

[0022] The conductive roll 10 comprises a shaft 12, an adhesive layer 18 formed on the outer peripheral surface of the shaft 12, an elastic layer 14 formed on the outer peripheral surface of the adhesive layer 18, and a surface layer 16 formed on the outer peripheral surface of the elastic layer 14. The elastic layer 14 is a layer (base layer) that forms the base of the conductive roll 10. The surface layer 16 is a layer that appears on the surface of the conductive roll 10. The adhesive layer 18 is disposed between the shaft 12 and the elastic layer 14 and is in contact with both. The adhesive layer 18 functions as a layer that bonds the shaft 12 and the elastic layer 14. The shaft 12 and the elastic layer 14 are bonded via the adhesive layer 18.

[0023] Generally, the shaft 12 may be made of any conductive material, and the material is not limited in this respect. However, in the present invention, the shaft 12 is made of a metallic material. The shaft 12 may be made of only a base material made of a metallic material, or may have one or more metal layers formed on the surface of the base material by plating or the like. In this case, the metal layer is formed to improve rust resistance and adhesion to the adhesive layer 18. From the viewpoint of cost, it is preferable that the shaft 12 be made of only a base material. However, from the viewpoint of excellent rust resistance and excellent adhesion to the adhesive layer 18, it is preferable that the shaft 12 have one or more metal layers on the surface of the base material.

[0024] Examples of the metal of the base material include iron and stainless steel. From the viewpoint of cost, iron is preferred as the metal of the base material. The metal layer formed on the surface of the base material is made of a metal having electrical conductivity. Examples of the metal of such a metal layer include nickel. From the viewpoints of workability, adhesion, etc., the metal layer formed on the surface of the base material is preferably formed by plating. There are electroless plating and electrolytic plating, but electroless plating is preferred from the viewpoints of excellent film thickness uniformity and fewer defects such as pinholes.

[0025] The thickness of the metal layer formed on the surface of the base material is preferably relatively thick (specifically, 10 μm or more) from the viewpoint of excellent rust prevention and excellent adhesion to the adhesive layer 18, but since this increases the cost, from the viewpoint of cost, it is preferable that the thickness be 3 μm or less.

[0026] The shape of the shaft body 12 is not particularly limited as long as it can be a shape that can form a shaft body, and it may be a solid round bar shape or a cylindrical shape with a hollowed-out interior.

[0027] The adhesive layer 18 is made of an adhesive composition containing an adhesive component (binder component). Examples of the adhesive component include phenolic resin adhesives, epoxy resin adhesives, nitrile rubber adhesives, acrylic resin adhesives, polyurethane adhesives, styrene-butadiene adhesives, and natural rubber adhesives. Only one of these adhesive components may be used, or two or more of these adhesive components may be used in combination.

[0028] The adhesive component of the adhesive composition is preferably a vulcanizing adhesive, from the viewpoint that it can be cured by heat and pressure during vulcanization of the elastic layer 14 and function as the adhesive layer 18. Examples of the vulcanizing adhesive include phenolic resin adhesives, epoxy resin adhesives, and nitrile rubber adhesives, among the adhesive components described above. Only one of these may be used, or two or more of these may be used in combination.

[0029] The adhesive composition may contain, as needed, a conductive agent (electronic conductive agent, ionic conductive agent) to impart conductivity, and may also contain one or more additives such as a vulcanizing agent (crosslinking agent), vulcanization accelerator, vulcanization aid (crosslinking aid), extender, reinforcing agent, processing aid, antioxidant, plasticizer, UV absorber, and lubricant.

[0030] The viscosity of the adhesive composition can be adjusted by using a solvent, such as methyl ethyl ketone (MEK) or methyl isobutyl ketone (MIBK), taking into consideration the application properties.

[0031] The thickness of the adhesive layer 18 is not particularly limited. It can be set to, for example, 1 μm or more and 100 μm or less. The thickness of the adhesive layer 18 is more preferably 3 μm or more and 50 μm or less, and even more preferably 5 μm or more and 10 μm or less. The volume resistivity of the adhesive layer 18 is not particularly limited, but from the viewpoint of excellent conductivity, it is preferably 1.0×10 2 ~5.0×10 5 It is preferable that the resistance is in the range of Ω·cm.

[0032] The elastic layer 14 is made of a conductive rubber composition containing a polymer containing a halogen atom, an ionic conductive agent, and a compound having an epoxy group and an ester group.

[0033] The polymer containing halogen atoms is contained as the main component of the rubber component of the conductive rubber composition. The main component is 50% by mass or more, more preferably 70% by mass or more, or 90% by mass or more. Examples of the polymer containing halogen atoms include hydrin rubber, chloroprene rubber, chlorinated butyl rubber, and chlorosulfonated polyethylene rubber. Of these, hydrin rubber is more preferred from the viewpoint of low resistance.

[0034] Examples of hydrin rubbers include epichlorohydrin homopolymer (CO), epichlorohydrin-ethylene oxide copolymer (ECO), epichlorohydrin-allyl glycidyl ether copolymer (GCO), and epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer (GECO).

[0035] The ionic conductive agent is composed of one or more of sulfonium salts, ammonium salts, phosphonium salts, and imidazolium salts. Of these, sulfonium salts and ammonium salts are more preferred from the viewpoint of thermal stability.

[0036] Examples of the cations of sulfonium salts, ammonium salts, phosphonium salts, and imidazolium salts include those having one or more alkyl or aryl groups having about 1 to 18 carbon atoms (e.g., methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, phenyl, and xylyl groups). The alkyl or aryl groups of the cations of sulfonium salts, ammonium salts, and phosphonium salts are particularly preferably those having 1 to 10 carbon atoms. Examples of the anions of sulfonium salts, ammonium salts, phosphonium salts, and imidazolium salts include F - ,Cl - ,Br - ,I - Halogen ions such as ClO4 - , BF4 - , PF6 - , SO4 2- , HSO4 - , C2H5SO4 - , CF3COO - , CF3SO3 - , (CF3SO2)2N - , (CF3CF2SO2)2N - , CF3(CF2)3SO3 - , (CF3SO2)3C - , CF3(CF2)2COO - Examples of anions of sulfonium salts, ammonium salts, and phosphonium salts include ClO4 - , PF6 - , (CF3SO2)2N - , CF3SO3 - etc. are more preferable.

[0037] The content of the ionic conductive agent is preferably 0.2 parts by mass or more per 100 parts by mass of the polymer containing halogen atoms, from the viewpoint of achieving an excellent effect of reducing resistance. It is more preferably 0.5 parts by mass or more, and even more preferably 1.0 part by mass or more. Furthermore, from the viewpoint of easily suppressing bleed-out of the ionic conductive agent, it is preferably 6.5 parts by mass or less per 100 parts by mass of the polymer containing halogen atoms, more preferably 6.0 parts by mass or less, and even more preferably 5.0 parts by mass or less.

[0038] The compound having an epoxy group and an ester group is blended into the elastic layer 14 to inhibit corrosion of the metal shaft 12 .

[0039] The elastic layer 14 contains a polymer containing halogen atoms, such as hydrin rubber. When halogen atoms are liberated from the polymer containing halogen atoms and react with moisture in the rubber, acids resulting from the halogen atoms, such as hydrochloric acid, may be generated. Acids resulting from halogen atoms can corrode the metal shaft 12. The epoxy groups in the compound react with and capture the acids resulting from halogen atoms, thereby preventing the acids resulting from halogen atoms from reaching the metal shaft 12.

[0040] To achieve low resistance, the elastic layer 14 contains an ionic conductive agent along with a polymer containing halogen atoms. The ionic conductive agent lowers the pH in the rubber, facilitating the corrosion of the metal shaft 12 by the acid caused by the halogen atoms. The ionic conductive agent also tends to bleed out due to polarization when current is applied. The epoxy group of the compound binds to the cations of the ionic conductive agent, thereby immobilizing (capturing) the ionic conductive agent. Furthermore, the ester group of the compound electrostatically adsorbs the cations and anions of the ionic conductive agent due to the strong dipole moment of the ester group, thereby immobilizing (capturing) the ionic conductive agent. This prevents the ionic conductive agent from bleeding out.

[0041] The content of the compound having an epoxy group and an ester group is 15 parts by mass or more relative to 100 parts by mass of the halogen-containing polymer in the elastic layer 14. Such a large amount of the compound provides excellent acid scavenging effect due to halogen atoms, thereby suppressing corrosion of the metal shaft 12. Furthermore, even when the elastic layer 14 contains an imidazolium salt as an ion conductive agent, corrosion of the metal shaft 12 can be suppressed. From this perspective, the content is preferably 18 parts by mass or more, more preferably 20 parts by mass or more, relative to 100 parts by mass of the halogen-containing polymer in the elastic layer 14. On the other hand, if the content is too high, the compound significantly affects the conductivity and hardness of the elastic layer 14, resulting in high electrical resistance or excessive hardness of the elastic layer 14. Therefore, the content is 43 parts by mass or less relative to 100 parts by mass of the halogen-containing polymer in the elastic layer 14. From this viewpoint, the content is preferably 40 parts by mass or less, and more preferably 35 parts by mass or less, relative to 100 parts by mass of the polymer containing a halogen atom in the elastic layer 14 .

[0042] The compound having an epoxy group and an ester group does not have an aromatic ring in its molecular structure. This allows the compound having an epoxy group and an ester group to have excellent compatibility with the rubber of the elastic layer 14, so a uniform acid-receiving effect can be obtained even if the content of the compound having an epoxy group and an ester group is high. If the compound having an epoxy group and an ester group has an aromatic ring in its molecular structure, it will have poor compatibility with the rubber of the elastic layer 14, making it difficult to obtain a uniform acid-receiving effect. In particular, the effect is significant when the content of the compound having an epoxy group and an ester group is high.

[0043] The weight-average molecular weight Mw of the compound having an epoxy group and an ester group is preferably 5,000 or more, from the viewpoint of easily suppressing bleeding of the compound. It is more preferably 7,000 or more, and even more preferably 9,000 or more. On the other hand, from the viewpoint of easily suppressing increases in hardness and resistance due to the compound, it is preferable that the weight-average molecular weight Mw is 150,000 or less, more preferably 100,000 or less, and even more preferably 50,000 or less.

[0044] In the conductive roll 10, the compound having an epoxy group and an ester group may or may not be contained in the adhesive layer 18 as long as it is contained in the elastic layer 14.

[0045] The conductive rubber composition may contain, in addition to the rubber component, a conductive agent (electronic conductive agent) to enhance conductivity, and may also contain, in addition to the rubber component, one or more additives such as vulcanizing agents (crosslinking agents), vulcanization accelerators, vulcanization aids (crosslinking aids), extenders, reinforcing agents, processing aids, antioxidants, plasticizers, UV absorbers, and lubricants.

[0046] Examples of electronic conductive agents include carbon black, graphite, potassium titanate, iron oxide, conductive titanium oxide, conductive zinc oxide, and conductive tin oxide. Examples of vulcanizing agents (crosslinking agents) include sulfur, peroxides, and hydrosilyl crosslinking agents. Examples of vulcanization aids (crosslinking aids) include zinc oxide, magnesium oxide, and hydrotalcite.

[0047] The thickness of the elastic layer 14 is not particularly limited, but is usually formed to about 0.1 to 10 mm, preferably 1 to 5 mm. From the viewpoint of excellent conductivity, the elastic layer 14 has a volume resistivity of 1.0×10 5 ~5.0×10 8 The elastic layer 14 may be a solid non-foamed material, or a foamed material such as a sponge.

[0048] The material of the surface layer 16 is not particularly limited, and examples thereof include polyamide (nylon), acrylic, urethane, silicone, and fluorine-based polymers. These polymers may be modified. Examples of the modified group include an N-methoxymethyl group, a silicone group, and a fluorine group.

[0049] To impart conductivity to the surface layer 16, a conductive agent such as carbon black, graphite, conductive titanium oxide, conductive zinc oxide, conductive tin oxide, or an ionic conductive agent (ammonium salt, phosphonium salt, borate, surfactant, etc.) may be appropriately added. Furthermore, various additives such as a crosslinking agent for the polymer component, a leveling agent, or a surface modifier may also be appropriately added as needed. Furthermore, to ensure surface roughness, roughness-forming particles may or may not be added to the surface layer 16.

[0050] The thickness of the surface layer 16 is not particularly limited, but is preferably in the range of 0.01 to 100 μm, more preferably in the range of 0.1 to 20 μm, and even more preferably in the range of 0.3 to 10 μm. The volume resistivity of the surface layer 16 is preferably 10 7 ~10 12 Ω·cm, more preferably 10 8 ~10 11 Ω·cm, more preferably 10 9 ~10 10 It is in the range of Ω·cm.

[0051] The conductive roll 10 can be produced by forming an adhesive layer 18 on the outer peripheral surface of the shaft 12, forming an elastic layer 14 on the outer peripheral surface of the adhesive layer 18, and forming a surface layer 16 on the outer peripheral surface of the elastic layer 14.

[0052] The adhesive layer 18 can be formed by applying the adhesive composition onto the outer peripheral surface of the shaft 12 and then performing a predetermined heat treatment. The heating temperature in the heat treatment is preferably 150 to 250° C. The heating time is preferably 30 to 60 minutes.

[0053] The elastic layer 14 can be formed by molding the conductive rubber composition into a layer. The conductive rubber composition can be molded by extrusion molding or molding. The conductive rubber composition is crosslinked and cured by heating during extrusion molding or molding.

[0054] The surface layer 16 can be formed by applying a surface layer-forming composition to the outer peripheral surface of the elastic layer 14, followed by heat treatment as necessary. The surface layer-forming composition may contain an appropriate solvent, such as an organic solvent such as methyl ethyl ketone (MEK), toluene, acetone, ethyl acetate, butyl acetate, methyl isobutyl ketone (MIBK), THF, or DMF, or a water-soluble solvent such as methanol or ethanol, in order to adjust the viscosity. Various coating methods, such as roll coating, dipping, and spray coating, can be used for the coating method.

[0055] The conductive roll 10 configured as described above includes a metal shaft 12, an adhesive layer 18 formed on the outer peripheral surface of the shaft 12, and an elastic layer 14 formed on the outer peripheral surface of the adhesive layer 18. The elastic layer 14 contains a polymer containing halogen atoms, an ionic conductive agent, and a compound having an epoxy group and an ester group. The compound having an epoxy group and an ester group captures acid generated by halogen atoms, thereby preventing the acid from reaching the metal shaft 12. The high content of the compound having an epoxy group and an ester group provides excellent corrosion prevention. The content of the compound having an epoxy group and an ester group is 43 parts by mass or less per 100 parts by mass of the polymer containing halogen atoms, thereby minimizing the effects of the compound on the conductivity and hardness of the elastic layer 14. Although the content of the compound having an epoxy group and an ester group is high, the compound having an epoxy group and an ester group does not have an aromatic ring in its molecular structure, resulting in excellent compatibility with the rubber of the elastic layer 14.

[0056] The conductive roll 10 includes a shaft 12, an adhesive layer 18, an elastic layer 14, and a surface layer 16 in this order, but the conductive roll for electrophotographic equipment according to the present invention is not limited to this configuration. For example, the conductive roll may have a configuration without the adhesive layer 18.

[0057] 2A is a schematic view of the appearance of a conductive roller for an electrophotographic device according to another embodiment of the present invention, and FIG. 2B is a cross-sectional view taken along line BB of the conductive roller. The conductive roller includes at least a metal shaft and an elastic layer disposed on the outer circumferential surface of the shaft.

[0058] The conductive roll 20 comprises a shaft 12, an elastic layer 14 formed on the outer peripheral surface of the shaft 12, and a surface layer 16 formed on the outer peripheral surface of the elastic layer 14. The conductive roll 20 comprises the shaft 12, the elastic layer 14, and the surface layer 16, in this order. In the conductive roll 20, the elastic layer 14 is in contact with both the shaft 12 and the surface layer 16. The conductive roll 20 differs from the conductive roll 10 only in the presence or absence of an adhesive layer 18, and is otherwise similar to the conductive roll 10, so a description of the overlapping parts will be omitted.

[0059] In the conductive roll 20, the compound having an epoxy group and an ester group is contained in the elastic layer 14. The compound having an epoxy group and an ester group is as described above.

[0060] The conductive roll 20 configured as described above includes a metal shaft 12 and an elastic layer 14 formed on the outer peripheral surface of the shaft 12. The elastic layer 14 contains a polymer containing halogen atoms, an ionic conductive agent, and a compound having an epoxy group and an ester group. The compound having an epoxy group and an ester group captures acid generated by halogen atoms, thereby preventing the acid from reaching the metal shaft 12. The high content of the compound having an epoxy group and an ester group provides excellent corrosion prevention. The content of the compound having an epoxy group and an ester group is 43 parts by mass or less per 100 parts by mass of the polymer containing halogen atoms, thereby minimizing the effects of the compound on the conductivity and hardness of the elastic layer 14. Although the content of the compound having an epoxy group and an ester group is high, the compound having an epoxy group and an ester group does not have an aromatic ring in its molecular structure, resulting in excellent compatibility with the rubber of the elastic layer 14.

[0061] The conductive rolls 10 and 20 are provided with a surface layer 16 on the outer periphery of the elastic layer 14 for reasons such as protecting the surface and imparting electrical properties, but the conductive roll for electrophotographic equipment according to the present invention is not limited to this configuration. For example, the conductive rolls 10 and 20 may be configured without the surface layer 16. Alternatively, instead of the surface layer 16, the surface of the elastic layer 14 may be subjected to a surface modification treatment. Examples of surface modification methods include a method of irradiating with UV or electron beams, and a method of contacting the elastic layer 14 with a surface modifier capable of reacting with unsaturated bonds or halogens, such as a compound containing a reactive group such as an isocyanate group, a hydrosilyl group, an amino group, a halogen group, or a thiol group.

[0062] The conductive roll according to the present invention can be used as a conductive roll such as a charging roll, a developing roll, a transfer roll, or a toner supply roll in electrophotographic equipment such as a copying machine, a printer, or a facsimile machine. [Example]

[0063] The present invention will be described in detail below using examples and comparative examples.

[0064] Example 1 <Preparation of Conductive Rubber Composition> 100 parts by mass of epichlorohydrin rubber (ECO) ["Hydrin T3106" manufactured by Nippon Zeon Co., Ltd.], 0.5 parts by mass of sulfur [manufactured by Tsurumi Chemical Industry Co., Ltd.] as a vulcanizing agent, 5.0 parts by mass of zinc oxide type 2 [manufactured by Mitsui Mining & Smelting Co., Ltd.] as a vulcanization aid, and 10.0 parts by mass of hydrotalcite [manufactured by Kyowa Chemical Industry Co., Ltd., product name "DHT4A"], 1.0 part by mass of vulcanization accelerator A [manufactured by Sanshin Chemical Industry Co., Ltd., product name "Suncerer CZ"], 1.0 part by mass of vulcanization accelerator B [manufactured by Ouchi Shinko Chemical Industry Co., Ltd., product name "Accel TBT"], ion conductive agent <1> 3.0 parts by mass of a compound <1> 25 parts by mass of the mixture was kneaded in a kneader to obtain a conductive rubber composition that would become the elastic layer material of the conductive roll.

[0065] Examples 2 to 5 A conductive rubber composition to be used as the elastic layer material of the conductive roll was obtained in the same manner as in Example 1, except that the type of compound was changed.

[0066] Examples 6 and 7 A conductive rubber composition to be used as the elastic layer material of the conductive roll was obtained in the same manner as in Example 2, except that the compounding amount of the compound was changed.

[0067] (Examples 8 to 10) A conductive rubber composition to be used as the elastic layer material of the conductive roll was obtained in the same manner as in Example 2, except that the type of ionic conductive agent was changed.

[0068] (Examples 11 to 12) A conductive rubber composition to be used as the elastic layer material of the conductive roll was obtained in the same manner as in Example 2, except that the amount of the ionic conductive agent added was changed.

[0069] Example 13 A conductive rubber composition to be used as the elastic layer material of the conductive roll was obtained in the same manner as in Example 2, except that the rubber material was changed.

[0070] (Comparative Examples 1 to 3) A conductive rubber composition to be used as the elastic layer material of the conductive roll was obtained in the same manner as in Example 2, except that the compounding amount of the compound was changed.

[0071] (Comparative Examples 4 to 6) A conductive rubber composition to be used as the elastic layer material of the conductive roll was obtained in the same manner as in Example 2, except that the type of compound was changed.

[0072] The following materials were prepared as a rubber material, a compound having an epoxy group and an ester group, and an ionic conductive agent.

[0073] (rubber materials) Chloroprene rubber [Showa Denko "Shopren GW"]

[0074] (ionic conductive agent) Ionic conductive agent <1> : Sulfonium salt, Nippon Carlit "PEL-25" (Li·ClO4, Li·CF3SO3) Ionic conductive agent <2> : Ammonium salt, TCI AMERICA "T0676" ((CH3)4N·OH) Ionic conductive agent <3> : Phosphonium salt, TCI AMERICA "H1047" ((n-Bu)3(CH3(CH2) 15 P·Br) Ionic conductive agent <4> : Imidazolium salt, "IL-IM1" manufactured by Koei Chemical

[0075] (Compounds having epoxy groups and ester groups) ·Compound <1> : The following synthetic product, weight average molecular weight Mw 5,000, no aromatic ring ·Compound <2> : The following synthetic product, weight average molecular weight Mw 100,000, no aromatic ring ·Compound <3> : The following synthetic product, weight average molecular weight Mw 150,000, no aromatic ring ·Compound <4> : The following synthetic product, weight average molecular weight Mw 1,000, no aromatic ring ·Compound <5> : The following synthetic product, weight average molecular weight Mw 210,000, no aromatic ring ·Compound <6> : Toa Gosei "ARUFON UG-4040" weight average molecular weight Mw 11,000, contains aromatic ring ·Compound <7> Mitsubishi Chemical "JER1256" weight average molecular weight Mw 50,000, contains aromatic rings ·Compound <8> : Toagosei "ARUFON UH-2170" weight average molecular weight Mw 14,000, contains aromatic ring

[0076] (Compound <1> ~ <5> (Method of synthesis of Glycidyl methacrylate (GMA, Sigma-Aldrich) and methyl methacrylate (MMA, Sigma-Aldrich) were used as starting materials, and azobisisobutyronitrile (AIBN, Sigma-Aldrich) was used as a reaction initiator. GMA and MMA were added to a three-neck flask and dissolved in toluene, after which AIBN was added. After stirring at 70°C under a nitrogen atmosphere for 4 hours, the mixture was cooled to room temperature and precipitated in methanol to separate the product. The precipitate was filtered and washed with methanol, and then vacuum dried to separate the compound. <1> ~ <5> obtained.

[0077] compound <1> Formulated with: GMA 178g (1.26 mol) MMA 126g (1.26 mol) AIBN 10g (0.061mol) Toluene 700 mL

[0078] compound <2> Formulated with: GMA 178g (1.26 mol) MMA 126g (1.26 mol) AIBN 1g (0.0061mol) Toluene 700 mL

[0079] compound <3> Formulated with: GMA 178g (1.26 mol) MMA 126g (1.26 mol) AIBN 0.33g (0.0020mol) Toluene 700 mL

[0080] compound <4> Formulated with: GMA 178g (1.26 mol) MMA 126g (1.26 mol) AIBN 50g (0.30mol) Toluene 700 mL

[0081] compound <5> Formulated with: GMA 178g (1.26 mol) MMA 126g (1.26 mol) AIBN 0.24g (0.0014mol) Toluene 700 mL

[0082] (Rust) The kneaded rubber was punched out into two 5cm diameter circles, an iron plate was sandwiched between the two resulting rubber circles, and the rubber circles and iron plate were heated simultaneously to create a sample. This sample was placed in an environmental chamber at 60°C and 95% RH for 1W (1 week). The iron plate was then removed from between the two rubber circles, and the surface of the iron plate was observed under a microscope (x20 magnification). Samples with no visible rust on the iron plate were marked "Good," samples with slight but acceptable rust were marked "Good," and samples with clearly visible rust were marked "Poor."

[0083] (Compatibility with rubber) When the kneaded rubber was passed through a 6-inch roller manufactured by Kansai Roll, if no residual compound was visually observed, it was marked with "Good", and if clear residual compound was observed, it was marked with "Poor".

[0084] (Ion bleeding) The kneaded rubber thus produced was heated in a press to produce a 2 mm thick sheet. The resulting sheet was placed in an environmental chamber at 60°C and 95% RH for 1 m (1 month). The surface of the sheet was then observed under a microscope (500x magnification). Sheets in which no bleeding due to the ionic conductive agent was observed on the sheet were marked with an "O" and sheets in which clear bleeding was observed were marked with an "X".

[0085] (volume electrical resistivity) The kneaded rubber was heated in a press to produce a 2 mm thick sheet sample. Electricity was applied to the obtained sample for 5 seconds at voltage levels in the range of 0.01-1000 V using a KEITHLEY volumetric electrical resistance measuring device. At that time, the resistance measured at 100 V was <1> - <6> When the difference compared to the sample without added salt was less than 0.7 [Log Ω cm], it was marked as "Good", and when it was 0.7 [Log Ω cm] or more, it was marked as "Poor".

[0086] (hardness) The kneaded rubber was heated in a press to produce 2.9cm set ball samples. The surface hardness of the obtained samples was measured using a micro rubber hardness tester "MD-1" manufactured by Kobunshi Keiki. A hardness of less than 40 was rated as "Good", 40 to less than 45 was rated as "△" (within the acceptable range), and 45 or more was rated as "Poor".

[0087] [Table 1]

[0088] [Table 2]

[0089] The rubber compositions for the elastic layer in Examples 1 to 13 were composed of a polymer containing a halogen atom (hydrin rubber or chloroprene rubber), an ionic conductive agent, and a compound having an epoxy group and an ester group (compound <1> Compounds from <5> The compositions include any one of the above, wherein the contents of the ion conductive agent and the compound having an epoxy group and an ester group are within a specific range, and the compound having an epoxy group and an ester group does not have an aromatic ring in its molecular structure. Examples 1 to 13 show that rust generation is suppressed and that the corrosion prevention effect is excellent. Furthermore, it is also shown that the content of the compound having an epoxy group and an ester group is within a specific range, and there are no problems in terms of volume electrical resistivity and hardness. Furthermore, although the content of the compound having an epoxy group and an ester group is high, the compound having an epoxy group and an ester group does not have an aromatic ring in its molecular structure, and therefore it is also shown that the compatibility with rubber is excellent.

[0090] The rubber composition for the elastic layer of Example 4 was a mixture of a polymer containing halogen atoms (hydrin rubber), an ionic conductive agent, and a compound having an epoxy group and an ester group (compound <4> ) and the compound <4> The molecular weight of the compound is relatively small. <4> Although the compound tends to bleed out in the composition and has a reduced effect of capturing acids caused by halogen atoms, the effect on core metal corrosion is within an acceptable range.

[0091] The rubber composition for the elastic layer of Example 6 was a mixture of a polymer containing halogen atoms (hydrin rubber), an ionic conductive agent, and a compound having an epoxy group and an ester group (compound <2> ) and, including compounds <2> Therefore, although the effect of capturing acids caused by halogen atoms is reduced, the effect on core metal corrosion is within an acceptable range.

[0092] The rubber composition for the elastic layer of Example 5 was a mixture of a polymer containing halogen atoms (hydrin rubber), an ionic conductive agent, and a compound having an epoxy group and an ester group (compound <5> ) and the compound <5> Although the molecular weight is large, the compatibility with hydrin rubber (polar rubber) is within the acceptable range. <5> Although the molecular weight of the polymer is large, it is hard, but this is within the acceptable range, and the effect on flexibility when made into a product is also within the acceptable range.

[0093] The rubber composition for the elastic layer of Example 7 was a mixture of a polymer containing halogen atoms (hydrin rubber), an ionic conductive agent, and a compound having an epoxy group and an ester group (compound <2> ) and the compound <2> Although the content of the compound is high, its compatibility with hydrin rubber (polar rubber) is within the acceptable range. <2> Although the content is high, it is hard, but this is within the acceptable range, and the effect on flexibility when made into a product is also within the acceptable range.

[0094] In contrast, the rubber compositions for the elastic layer of Comparative Examples 1 and 2 contain a polymer containing halogen atoms (hydrin rubber), an ionic conductive agent, and a compound having an epoxy group and an ester group (compound <2> ), but the content of the compound having an epoxy group and an ester group is too small. For this reason, it is clear that the occurrence of rust cannot be suppressed and the corrosion prevention effect is poor. The rubber composition for the elastic layer of Comparative Example 3 contains a polymer containing a halogen atom (hydrin rubber), an ionic conductive agent, and a compound having an epoxy group and an ester group (compound <2> ), but the content of compounds with epoxy and ester groups is too high. This results in high resistance, impairing the electrical properties of the product. It also has high hardness, which impairs flexibility when made into a product, leading to image streaks.

[0095] The rubber composition for the elastic layer of Comparative Example 4 contains a polymer containing halogen atoms (hydrin rubber), an ionic conductive agent, and a compound having an epoxy group and an ester group, but the compound having an epoxy group and an ester group has an aromatic ring in its molecular structure. The compound itself has a reduced polarity, which reduces its dispersibility in the hydrin rubber (polar rubber) and its compatibility. This reduces the rust prevention effect.

[0096] The rubber composition for the elastic layer of Comparative Example 5 was a compound <7> However, although it has an epoxy group, it does not have an ester group. Therefore, the ionic conductive agent cannot be immobilized, and the bleeding out of the ionic conductive agent cannot be prevented. <7> However, they have aromatic rings in their molecular structure. This reduces the polarity of the compound itself, making them less dispersible in hydrin rubber (polar rubber) and less compatible. This reduces their rust prevention effect.

[0097] The rubber composition for the elastic layer of Comparative Example 6 was a compound <8> However, although it has an ester group, it does not have an epoxy group. Therefore, it cannot capture the acid caused by the halogen atom, and the corrosion of the core metal cannot be suppressed. <8> However, it has an aromatic ring in its molecular structure. Because the polarity of the compound itself is reduced, it has poor dispersibility in hydrin rubber (polar rubber) and poor compatibility.

[0098] Although the embodiments and examples of the present invention have been described above, the present invention is not limited to the above embodiments and examples, and various modifications are possible within the scope of the invention. [Explanation of symbols]

[0099] 10,20 Conductive roll 12 shaft body 14 Elastic layer 16 Surface layer 18 Adhesive layer

Claims

1. The device comprises at least a metal shaft body and an elastic layer disposed on the outer circumferential surface of the shaft body, the elastic layer includes a polymer containing a halogen atom, an ion conductive agent, and a compound having an epoxy group and an ester group; the content of the ion conductive agent is 0.2 parts by mass or more and 6.5 parts by mass or less with respect to 100 parts by mass of the polymer containing a halogen atom, the content of the compound having an epoxy group and an ester group is 15 parts by mass or more and 43 parts by mass or less relative to 100 parts by mass of the polymer containing a halogen atom, The conductive roll for electrophotographic equipment, wherein the compound having an epoxy group and an ester group does not have an aromatic ring in its molecular structure.

2. 2. The conductive roll for an electrophotographic apparatus according to claim 1, wherein the polymer containing a halogen atom is a hydrin rubber.

3. 3. The conductive roll for electrophotographic equipment according to claim 1, wherein the compound having an epoxy group and an ester group has a weight average molecular weight Mw of 5,000 or more and 150,000 or less.

4. 3. The conductive roll for electrophotographic equipment according to claim 1, wherein the ionic conductive agent is composed of one or more of sulfonium salts, ammonium salts, phosphonium salts, and imidazolium salts.

5. 3. The conductive roll for electrophotographic equipment according to claim 1, wherein said shaft and said elastic layer are bonded to each other via an adhesive layer.

6. 3. The conductive roll for electrophotographic equipment according to claim 1, wherein said shaft and said elastic layer are directly bonded to each other.

7. the polymer containing a halogen atom is a hydrin rubber, the weight average molecular weight Mw of the compound having an epoxy group and an ester group is 5,000 or more and 150,000 or less; the ion conductive agent is composed of one or more of a sulfonium salt, an ammonium salt, a phosphonium salt, and an imidazolium salt, 2. The conductive roll for electrophotographic equipment according to claim 1, wherein said shaft and said elastic layer are bonded to each other via an adhesive layer.

8. the polymer containing a halogen atom is a hydrin rubber, the weight average molecular weight Mw of the compound having an epoxy group and an ester group is 5,000 or more and 150,000 or less; the ion conductive agent is composed of one or more of a sulfonium salt, an ammonium salt, a phosphonium salt, and an imidazolium salt, 2. The conductive roll for electrophotographic equipment according to claim 1, wherein said shaft and said elastic layer are directly bonded to each other.

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