JP2009075435A - Conductive composition for electrophotographic equipment, conductive cross-linking body for electrophotographic equipment, and conductive member for electrophotographic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide conductive composition for electrophotographic apparatus for forming a conductive member for an electrophotographic apparatus whose resistance is low and by which bloom of an ion conductive agent is suppressed. <P>SOLUTION: The composition contains a rubber polymer such as hydrin rubber, a radical polymerizable monomer having a tertiary amine group, a radical polymerization initiator and the ion conductive agent. The radical polymerizable monomer can be (meth)acrylamide or the like such as N,N-dimethylaminopropylacrylamide or (meth)acrylic ester such as N,N-dimethylaminoethylacrylate. It is preferable that the conductive composition contains the radical polymerizable monomer by 1 to 50 pts.mass and the ion conductive agent by 0.1 to 10 pts.mass to 100 pts.mass of the rubber polymer. The conductive composition is suitably used for base layer material of the conductive roll for the electrophotographic apparatus 10 such as a developing roll or a charging roll formed by layering a base layer 14 and a surface layer 16 in this order on the outer periphery of a shaft body 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a conductive composition for electrophotographic equipment, a conductive crosslinked body for electrophotographic equipment, and a conductive member for electrophotographic equipment.

  In recent years, electrophotographic apparatuses such as copying machines, printers, and facsimiles that employ an electrophotographic system have been widely used. In general, a photosensitive drum is incorporated in the electrophotographic apparatus, and conductive rolls such as a charging roll, a developing roll, a transfer roll, and a toner supply roll are disposed around the photosensitive drum.

  In an electrophotographic apparatus, generally, an electrostatic charge is applied to the surface of a photosensitive drum by a charging roll, an image is exposed thereon to form an electrostatic latent image, and development is performed by attaching toner to the electrostatic latent image by a developing roll. Then, the toner image is transferred onto a recording paper, and the recording paper on which the toner image has been transferred is heated and pressed to fix the toner on the recording paper, thereby forming an image.

  In forming an image with an electrophotographic apparatus, in order to obtain a highly accurate image, the conductive roll is required to have uniform and stable electrical characteristics. That is, the conductive roll is required to be electrically low resistance, to have a small variation in the electrical resistance value in the entire roll (the electrical resistance is uniform), and the like.

  In order to adjust the conductivity, a conductive agent is added to the conductive roll as necessary. The conductive agent includes an electronic conductive agent such as carbon black and an ionic conductive agent such as a quaternary ammonium salt, which are properly used as necessary.

  When an electronic conductive agent is added, it is easy to lower the electrical resistance of the rubber forming the roll, and a low resistance conductive roll is easily obtained. On the other hand, the dispersion of the electronic conductive agent in the rubber constituting the roll is easily affected by the kneading state, and has an instability in which the electric resistance value is likely to change depending on the processing history.

  On the other hand, when an ionic conductive agent is added, since the ionic conductive agent can be dispersed at the molecular level in the rubber constituting the roll, the electrical resistance value of the conductive roll to which the ionic conductive agent is added is Less dependent on machining history and relatively stable.

  For example, Patent Document 1 discloses a developing roll in which a base rubber layer formed on the outer periphery of a shaft body contains an ionic conductive agent.

JP 2003-15404 A

  When an ionic conductive agent is added, the electrical resistance of the rubber forming the roll is unlikely to decrease. Therefore, in order to reduce the resistance of the conductive roll, it is necessary to increase the addition amount of the ionic conductive agent.

  However, since the ionic conductive agent itself is hardly soluble in polymers such as rubber, when the amount of the ionic conductive agent added is increased, the ionic conductive agent does not dissolve in the rubber (not ionized) and remains in the salt state from the rubber matrix. There was a problem that the electrical resistance did not decrease to a desired resistance value due to blooming out.

  The problem to be solved by the present invention is to provide a conductive composition for electrophotographic equipment which forms a conductive member for electrophotographic equipment with low resistance and suppressed bloom of an ionic conductive agent. Another object is to provide a conductive cross-linked body for electrophotographic equipment which forms a conductive member for electrophotographic equipment with low resistance and suppressed bloom of an ionic conductive agent. It is another object of the present invention to provide a conductive member for electrophotographic equipment that has low resistance and suppresses blooming of an ionic conductive agent.

  In order to solve the above problems, the electroconductive composition for an electrophotographic apparatus according to the present invention contains a rubber polymer, a radical polymerizable monomer having a tertiary amine group, a radical polymerization initiator, and an ionic conductive agent. Is the gist.

  At this time, the radical polymerizable monomer is desirably one or more selected from (meth) acrylamides and (meth) acrylic acid esters.

  The radical polymerizable monomer is one or two selected from N, N-dimethylaminopropylacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, and N, N-dimethylaminoethyl acrylate. It should be more than seeds.

  The rubber polymer may be a rubber polymer having a polar group.

  At this time, it is desirable to contain 1-50 mass parts of said radically polymerizable monomers with respect to 100 mass parts of said rubber polymers.

  Moreover, it is desirable to contain 0.1-10 mass parts of said ionic conductive agents with respect to 100 mass parts of said rubber polymers.

  Furthermore, the mass ratio of the radical polymerizable monomer to the ionic conductive agent is preferably in the range of 0.1 to 100.

  The electroconductive cross-linked product for an electrophotographic apparatus according to the present invention is characterized in that the rubber polymer is co-crosslinked with a radical polymerizable monomer having a tertiary amine group and contains an ionic conductive agent. To do.

  In addition, the electroconductive crosslinked body for an electrophotographic apparatus according to the present invention is summarized in that the electroconductive composition is co-crosslinked.

  The gist of the electroconductive member for electrophotographic equipment according to the present invention is that the above electroconductive crosslinked body is used.

  The electroconductive composition for electrophotographic equipment according to the present invention has a tertiary amine group in a radical polymerizable monomer that co-crosslinks a rubber polymer. Therefore, the addition amount of the ionic conductive agent can be increased without blooming the ionic conductive agent. Thereby, the conductive crosslinked body which bridge | crosslinked this electrically conductive composition is low resistance, and the bloom of an ionic conductive agent is suppressed.

  This is because the tertiary amine group of the ionic unit capable of coordinating the ions of the ionic conductive agent is introduced into the rubber polymer from the outside of the rubber polymer and incorporated into the crosslinked structure, thereby forming a polymer matrix with high ion coordination ability. It is inferred that In other words, the ion coordinating ability of the polymer matrix is increased, so that the ionization efficiency of the ion conductive agent is increased (the solubility of the ion conductive agent is improved), and the ion conductive agent is retained and stabilized in the polymer matrix. Therefore, it is presumed that the bloom of the ionic conductive agent was suppressed while having a low resistance.

  At this time, if the radical polymerizable monomer is one or more selected from (meth) acrylamides and (meth) acrylic acid esters, the above effect is excellent.

  And the radically polymerizable monomer is one or two selected from N, N-dimethylaminopropylacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, and N, N-dimethylaminoethyl acrylate. It is excellent in the said effect especially that it is a seed or more.

  Furthermore, when the rubber polymer is a rubber polymer having a polar group, the bloom of the ionic conductive agent is further suppressed, and the resistance can be reduced.

  At this time, when 1 to 50 parts by mass of the radical polymerizable monomer is contained with respect to 100 parts by mass of the rubber polymer, the balance between electric resistance and hardness is excellent.

  Moreover, when 0.1-10 mass parts of said ionic conductive agents are contained with respect to 100 mass parts of said rubber polymers, it is excellent in the balance of an electrical resistance and a bloom inhibitory effect.

  Furthermore, when the mass ratio of the radical polymerizable monomer to the ionic conductive agent is in the range of 0.1 to 100, the bloom of the ionic conductive agent can be effectively suppressed.

  On the other hand, the electroconductive cross-linked product for electrophotographic equipment according to the present invention is formed by co-crosslinking between the rubber polymers with a radical polymerizable monomer having a tertiary amine group, and the rubber polymer contains an ionic conductive agent. Further, the conductive composition is co-crosslinked. Therefore, if this is used, it is possible to form a conductive member for electrophotographic equipment with low resistance and suppressed bloom of the ionic conductive agent.

  And the electroconductive bridge | crosslinking body is used for the electroconductive member for electrophotographic apparatuses which concerns on this invention. Therefore, the resistance is low and the bloom of the ionic conductive agent is suppressed.

  The electroconductive composition for electrophotographic equipment according to an embodiment of the present invention will be described in detail.

  The conductive composition for electrophotographic equipment according to the present invention (hereinafter sometimes referred to as a conductive composition) contains a rubber polymer, a radical polymerizable monomer, a radical polymerization initiator, and an ionic conductive agent. ing.

  The rubber polymer may be a solid rubber or a liquid rubber. Moreover, the rubber polymer which has a polar group may be sufficient, and the rubber polymer which does not have a polar group may be sufficient. Among these, a rubber polymer having a polar group is more preferable from the viewpoint of having a polar group and dissociating the ionic conductive agent into ions to facilitate dissolution. The rubber polymer having a polar group is a polymer having a polar group such as a chloro group, a nitrile group, a carboxyl group, or an alkylene oxide group, and preferably has rubber elasticity.

  Specific examples of the rubber polymer include epichlorohydrin homopolymer (CO), epichlorohydrin-ethylene oxide binary copolymer (ECO), epichlorohydrin-allyl glycidyl ether binary copolymer (GCO), epichlorohydrin-ethylene oxide. -Hydrin rubber such as allylic glycidyl ether terpolymer (GECO), nitrile rubber such as acrylonitrile-butadiene rubber (NBR), hydrogenated acrylonitrile-butadiene rubber (H-NBR), urethane rubber, ethylene-propylene rubber (EPDM), styrene-butadiene rubber (SBR), polynorbornene rubber, silicone rubber, butadiene rubber (BR), isoprene rubber (IR), acrylic rubber (ACM), chloroprene rubber (CR), fluoro rubber Natural rubber (NR), and the like can be exemplified. These may be used alone or in combination. More preferred are hydrin rubber, nitrile rubber, urethane rubber, and chloroprene rubber (CR), which are rubber polymers having polar groups.

  As described above, the rubber polymer having a polar group can contribute to dispersion of the ionic conductive agent at the molecular level by having the polar group. From this point of view, it can be said that those containing more polar groups are preferable. On the other hand, since the crystallinity of the rubber polymer itself increases as the number of polar groups increases, it tends to lead to an increase in the polymer viscosity and the hardness of the rubber after crosslinking, and a deterioration in compression set. Therefore, it is preferable to have a polar group to such an extent that the crystallinity of the rubber polymer itself does not become too high.

  For the above reasons, for example, when the rubber polymer having a polar group is a hydrin rubber, the ethylene oxide (EO) content in the hydrin rubber is preferably in the range of 30 to 75 mol%. When the rubber polymer having a polar group is a nitrile rubber, the nitrile (AN) content in the nitrile rubber is preferably in the range of 18 to 50 mol%.

  The radically polymerizable monomer is used for co-crosslinking the rubber polymers in the presence of a radical polymerization initiator. The radical polymerizable monomer is a compound having a carbon-carbon unsaturated bond having radical reactivity, such as a compound having a (meth) acryloyl group or a compound having a (meth) acrylamide group ((meth) acrylamides). Etc. are preferable. Examples of the compound having a (meth) acryloyl group include (meth) acrylic acid esters.

  The radical polymerizable monomer has a tertiary amine group. The tertiary amine group is considered to have a function of easily dissociating the ionic conductive agent into ions and facilitating dissolution of the ionic conductive agent in the polymer matrix. The tertiary amine group may be at the terminal of the radical polymerizable monomer or may be in the internal skeleton.

  For example, when the radical polymerizable monomer is a (meth) acrylamide, the amide moiety may be a tertiary amine group, or a substituent such as an aminoalkyl group derived from the amide moiety is a tertiary amine. It may be the basis. Further, for example, when the radical polymerizable monomer is a (meth) acrylic acid ester, a tertiary amine group may be contained in the ester group. That is, when the radical polymerizable monomer is a (meth) acrylic acid ester, it is only necessary to have an aminoalkyl ester group in the molecule.

  In the tertiary amine group, the nitrogen atom is bonded to two alkyl groups in addition to the radical polymerizable monomer skeleton. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and an isobutyl group. The two alkyl groups may be the same type of alkyl group or different types of alkyl groups.

  Specific examples of the radical polymerizable monomer include N, N-dimethylaminopropylacrylamide (DMAPAA), N, N-dimethylacrylamide (DMAA), N, N-diethylacrylamide (DEAA), N, N- Preferred examples include dimethylaminoethyl acrylate dimethylaminopropyl acrylamide (DMAEA) and the like.

  The radical polymerizable monomer is preferably contained in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the rubber polymer. When the content of the radical polymerizable monomer is less than 1 part by mass, the electrical resistance of the (cured product) crosslinked product becomes high, and it is difficult to reduce the resistance. On the other hand, when the content of the radical polymerizable monomer exceeds 50 parts by mass, the hardness of the crosslinked product is increased, and for example, when used as an elastic layer of a conductive roll for electrophotographic equipment, the image tends to deteriorate.

  The lower limit of the content of the radical polymerizable monomer is more preferably 5 parts by mass or more, and still more preferably 10 parts by mass or more with respect to 100 parts by mass of the rubber polymer. On the other hand, the upper limit of the content of the radical polymerizable monomer is more preferably 30 parts by mass or less, and still more preferably 20 parts by mass or less, with respect to 100 parts by mass of the rubber polymer.

  Examples of the radical polymerization initiator contained in the conductive composition include peroxides and azo compounds. These can be used alone or in combination of two or more.

  Examples of the peroxide include dicumyl peroxide (DCP), benzoyl peroxide, dichlorobenzoyl peroxide, di-tert-butyl peroxide, butyl peracetate, tert-butyl perbenzoate, and 2,5-dimethyl-2. , 5-Di (tert-butylperoxy) hexane, 1,1-di- (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di- (benzoyl) Peroxy) hexane, 2,5-dimethyl-2,5-di- (benzoylperoxy) -3-hexene, di-tert-butylperoxydiisopropylbenzene, tert-butylcumyl peroxide, 2,5-dimethyl- 2,5-di- (tert-butylperoxy) -3-hexene, 1 3-bis (tert-butylperoxyisopropyl) benzene, n-butyl-4,4-bis (tert-butylperoxy) valerate, p-chlorobenzoyl peroxide, tert-butylperoxyisopropyl carbonate, diacetyl peroxide, A lauroyl peroxide etc. can be illustrated.

  Examples of the azo compound include 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2,4,4-trimethylpentene), and 2,2′-azobis (2-methylpropane). ), 2-cyano-2-propyrazoformamide, 2,2′-azobis (2-hydroxy-methylpropionate), 2,2′-azobis (2-methyl-butyronitrile), 2,2′-azobis Examples include isobutyronitrile, 2,2′-azobis [2- (2-imidazolin-2-yl) propane], dimethyl 2,2′-azobis (2-methylpropionate), and the like.

  The lower limit of the content of the radical polymerization initiator is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and further preferably 1 part by mass with respect to 100 parts by mass of the polymer having a polar group. It is good that it is more than part. On the other hand, the upper limit of the content of the radical polymerization initiator is preferably 50 parts by mass or less, more preferably 10 parts by mass or less, with respect to 100 parts by mass of the polymer having a polar group.

  The ionic conductive agent has a function of adjusting the electrical resistance of the crosslinked body of the conductive composition. When the ion conductive agent is dissociated into ions in the polymer matrix to be in an ionic state, the ion conductive agent dissolves in the polymer matrix and can be dispersed at a molecular level. Therefore, as compared with an electronic conductive agent such as carbon black, there is less dependency on the processing history such as variation due to kneading state, and the dispersibility tends to be good. Therefore, resistance unevenness is relatively less likely to occur.

  The ionic conductive agent is not particularly limited, and any ionic conductive agent can be used as long as it can be used in the field of electrophotographic equipment.

  Examples of the ionic conductive agent include a quaternary ammonium salt represented by the following formula (1), a borate represented by the following formula (2), and a surfactant. These may be used alone or in combination.

In the following formula (1), R 1, R 2, R 3 and R 4 are alkyl groups or aryl groups having 1 to 18 carbon atoms, methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, decyl group , Phenyl group, xylyl group and the like, X ^n- represents an n-valent anion, and n represents an integer of 1 to 6. Examples of the n-valent anion include halogen ion, ClO ₄ ⁻ , BF ₄ ⁻ , SO ₄ ²⁻ , HSO ₄ ⁻ , C ₂ H ₅ SO ₄ ^{− and the} like.

In the following formula (2), R1, R2, R3, and R4 are alkyl groups or aryl groups having 1 to 18 carbon atoms, and are methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, Decyl group, phenyl group, xylyl group, etc., M ^{n +} is an alkali metal ion or alkaline earth metal ion, lithium ion, sodium ion, potassium ion, calcium ion, etc., n is an integer of 1-2 Show.

  The ionic conductive agent is preferably contained in an amount of 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber polymer. If the content of the ionic conductive agent is less than 0.1 parts by mass, the (cured product) crosslinked product has an increased electrical resistance, making it difficult to reduce the resistance. On the other hand, even if the content of the ionic conductive agent exceeds 10 parts by mass, the effect of reducing the electrical resistance of the crosslinked body is difficult to improve, and conversely, the bloom suppressing effect tends to be reduced.

  The lower limit of the content of the ionic conductive agent is more preferably 0.3 parts by mass or more, and still more preferably 0.5 parts by mass or more with respect to 100 parts by mass of the rubber polymer. On the other hand, the upper limit of the content of the ionic conductive agent is more preferably 8 parts by mass or less, and further preferably 5 parts by mass or less, with respect to 100 parts by mass of the rubber polymer.

  It is considered that the radical polymerizable monomer facilitates dissociation of the ionic conductive agent into ions due to the tertiary amine group and facilitates dissolution of the ionic conductive agent in the polymer matrix. Therefore, the mass ratio of the radical polymerizable monomer to the ionic conductive agent is preferably in the range of 0.1 to 100. If the mass ratio is less than 0.1, the effect of easily dissolving the ionic conductive agent in the polymer matrix tends to be reduced. On the other hand, if the mass ratio exceeds 100, the effect of reducing the electrical resistance of the polymer matrix due to the ionic conductive agent is difficult to improve, the number of co-crosslinking points due to the radical polymerizable monomer increases, and the hardness of the crosslinked body tends to increase. .

  The lower limit value of the mass ratio is more preferably 1 or more, and still more preferably 2 or more. On the other hand, the upper limit value of the mass ratio is more preferably 50 or less, and still more preferably 20 or less.

  In addition to the above, the conductive composition according to the present invention includes a lubricant, a vulcanization accelerator, an anti-aging agent, a light stabilizer, a viscosity modifier, a processing aid, a flame retardant, a plasticizer, and a foaming agent. In addition, one or more various additives such as a filler, a dispersant, an antifoaming agent, a pigment, and a release agent may be contained.

  The conductive composition according to the present invention is co-crosslinked and used for a conductive member for electrophotographic equipment. As a conductive member for an electrophotographic apparatus, for example, a roll-shaped conductive member (conductive roll) such as a charging roll, a developing roll, a transfer roll, and a toner supply roll used in an electrophotographic apparatus, or an electrophotographic apparatus And a belt-like conductive member (conductive belt) such as a transfer belt. In particular, it is suitably used for conductive rolls used in a state where they are pressed against each other with a constant load, such as a photosensitive drum for a charging roll and a developing blade for a developing roll. The conductive composition according to the present invention is preferably used as a base layer material for a conductive member.

  Next, the electroconductive crosslinked body for electrophotographic equipment according to the present invention will be described.

  The conductive crosslinked body for electrophotographic equipment according to the present invention (hereinafter sometimes referred to as a conductive crosslinked body) is co-crosslinked with a radical polymerizable monomer having a tertiary amine group between rubber polymers, It contains a conductive agent. The types and contents of the rubber polymer, radical polymerizable monomer, and ionic conductive agent may be those described above.

  The conductive cross-linked product according to the present invention is only required to be co-crosslinked with a radical polymerizable monomer having a tertiary amine group between rubber polymers and to contain an ionic conductive agent. Is not to be done. As a method of co-crosslinking, a method using a radical reaction is preferable. In this case, a radical polymerization initiator may be contained in the conductive composition forming the conductive crosslinked body. The kind and content of the radical polymerization initiator may be the kind and content described above.

  In addition, the conductive composition forming the conductive crosslinked body may further contain one or more of the various additives described above as necessary.

  Next, the electroconductive member for electrophotographic equipment according to the present invention will be described. The electroconductive member for electrophotographic equipment according to the present invention is formed using the electroconductive crosslinked body for electrophotographic equipment.

  As described above, the electrophotographic apparatus conductive member may be a roll-shaped electroconductive member (conductive roll) such as a charging roll, a developing roll, a transfer roll, or a toner supply roll used in an electrophotographic apparatus, or an electrophotography. Examples thereof include a belt-like conductive member (conductive belt) such as a transfer belt used in equipment. Particularly, it is suitable for a conductive roll that is used in a state of being pressed with a constant load, such as a photosensitive drum for a charging roll and a developing blade for a developing roll.

  1 and 2 show an example of a conductive roll as a conductive member for an electrophotographic apparatus according to the present invention. 1 and 2 are circumferential cross-sectional views showing an example of a conductive roll according to the present invention.

  The conductive roll 10 shown in FIG. 1 has a laminated structure in which a base layer 14 and a surface layer 16 are laminated in this order on the outer periphery of a shaft body 12. On the other hand, the conductive roll 10 shown in FIG. 2 has a laminated structure in which the base layer 14, the intermediate layer 18, and the surface layer 16 are laminated in this order on the outer periphery of the shaft body 12. In addition, as a structure of an electroconductive roll, it is not limited to the structure shown in FIG. 1 and FIG.

  The shaft body 12 is not particularly limited as long as it has conductivity. Specific examples include solid bodies made of metal such as iron, stainless steel, and aluminum, and a cored bar made of a hollow body. You may apply | coat an adhesive agent, a primer, etc. to the surface of the shaft body 12 as needed. The adhesive, primer, etc. may be made conductive as necessary.

  A rubber polymer is used as a main material for forming the base layer 14. As the rubber polymer, the above rubber polymer may be used. The composition forming the base layer 14 contains a radical polymerizable monomer having a tertiary amine group in order to cross-link between the rubber polymers as the main material. The type and content of the radical polymerizable monomer may be as described above. The method of co-crosslinking is not particularly limited, but in the case of co-crosslinking by a radical reaction, a radical polymerization initiator may be contained in the composition forming the base layer 14. The kind and content of the radical polymerization initiator may be the kind and content described above.

  The composition forming the base layer 14 further contains an ionic conductive agent. The kind and content of the ionic conductive agent may be the kind and content described above. Furthermore, you may contain the above-mentioned various additive 1 type (s) or 2 or more types as needed.

As the composition for forming the base layer 14, the above-described conductive composition is preferably used. In order to further improve the conductivity, a known conductive agent such as carbon black, graphite, c-TiO ₂ , c-ZnO, c-SnO ₂ (c means conductivity) or a foaming agent. Alternatively, a conductive composition to which a softener or the like is appropriately added may be used.

  The base layer 14 is coaxially placed in the hollow portion of the roll molding die, the base layer forming composition is injected, heated and cured, and then demolded (injection method). The base layer forming composition may be extruded on the surface of the shaft body 12 (extrusion method). When a plurality of base layers 14 are formed, the operation according to the above method may be repeated.

The thickness of the base layer 14 is not particularly limited, but is preferably 0.1 to 10 mm, more preferably 1 to 5 mm. The volume resistivity of the base layer 14 is preferably in the range of 10 ² to 10 ¹⁰ Ω · cm, more preferably 10 ³ to 10 ⁹ Ω · cm, and still more preferably in the range of 10 ⁴ to 10 ⁸ Ω · cm. Good to be inside.

  The intermediate layer 18 can function as a resistance adjustment layer. A rubber elastic material can be suitably used as the main material for forming the intermediate layer 18. Examples of the rubber elastic material include epichlorohydrin homopolymer (CO), epichlorohydrin-ethylene oxide binary copolymer (ECO), epichlorohydrin-allyl glycidyl ether binary copolymer (GCO), epichlorohydrin-ethylene oxide-allyl. Hydrin rubber such as glycidyl ether terpolymer (GECO), ethylene-propylene rubber (EPDM), styrene-butadiene rubber (SBR), polynorbornene rubber, silicone rubber, butadiene rubber (BR), isoprene rubber (IR), Acrylic rubber (ACM), Chloroprene rubber (CR), Urethane rubber, Urethane elastomer, Fluoro rubber, Natural rubber (NR), Acrylonitrile-butadiene rubber (NBR), Hydrogenated acrylonitrile-butadiene Beam (H-NBR), and the like can be exemplified. These may be used alone or in combination.

  As the rubber elastic material, silicone rubber, acrylonitrile-butadiene rubber (NBR), hydrin rubber, urethane-based elastomer and the like are preferable from the viewpoints of electrical resistance controllability, set resistance, and the like.

In order to impart conductivity to the intermediate layer 18, carbon black, graphite, c-TiO ₂ , c-ZnO, c-SnO ₂ (c- means conductivity), an ionic conductive agent (quaternary ammonium). Conventionally known conductive agents such as salts, borates, surfactants, etc.) can be appropriately added. Furthermore, if necessary, a foaming agent, a crosslinking agent, a crosslinking accelerator, a softening agent (oil) and the like may be appropriately added.

  In order to form the intermediate layer 18 on the outer periphery of the base layer 14, the shaft body 12 on which the base layer 14 is formed is coaxially installed in the hollow portion of the roll molding die, and the intermediate layer forming composition is injected. After heating and curing, demolding (injection method), extruding a composition for forming an intermediate layer on the surface of the base layer 14 (extrusion method), roll coating method, dipping method, spray coating method, etc. The intermediate layer forming composition may be applied to the surface of the base layer 14 by various coating methods. When a plurality of intermediate layers 18 are formed, an operation according to the above method may be repeated.

The thickness of the intermediate layer 18 is not particularly limited, but is preferably 0.001 to 2 mm, more preferably 0.01 to 0.5 mm. The volume resistivity of the intermediate layer 18 is preferably in the range of 10 ⁴ to 10 ¹⁰ Ω · cm, more preferably 10 ⁵ to 10 ⁹ Ω · cm, and still more preferably in the range of 10 ⁶ to 10 ⁸ Ω · cm. Good to be inside.

  The surface layer 16 can function as a protective layer on the roll surface. The main material for forming the surface layer 16 is not particularly limited. For example, urethane resin, polyamide, acrylic resin, acrylic silicone resin, butyral resin, alkyd resin, polyester resin, fluororubber, fluororesin, silicone resin, Acrylic modified silicone resins, silicone modified acrylic resins, fluorine modified acrylic resins, melamine resins, methacrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, epoxy resins, phenolic resins, polybutylene terephthalate, polyacetal, modified polyphenylene oxide (modified polyphenylene) Ether), polyphenylene sulfide, polyether ether ketone, polyether sulfone, polysulfone, polyamideimide, polyetherimide, polyimid , Polyarylate, polyallyl ether nitrile, nitrile rubber, urethane rubber, and the like can be exemplified those crosslinked resins. These may be used alone or in combination. In particular, from the viewpoint of excellent wear resistance, a crosslinked urethane resin, acrylic resin, acrylic-modified silicone resin, fluorine-modified acrylic resin, urethane rubber, polyamide, and the like can be suitably used.

The surface layer 16 is, for imparting conductivity, carbon black, _{graphite, c-TiO 2, c-} ZnO, c-SnO 2 (c- means conductive.), Ion conductive agent (quaternary ammonium salt Conventionally known conductive agents such as borates, surfactants, etc.) can be appropriately added.

  In addition to the above, the composition forming the surface layer 16 may be a lubricant, a vulcanization accelerator, an anti-aging agent, a light stabilizer, a viscosity modifier, a processing aid, a flame retardant, a plasticizer, a foaming agent, You may contain 1 type, or 2 or more types of various additives, such as a filler, a dispersing agent, an antifoamer, a pigment, and a mold release agent.

  The composition forming the surface layer 16 preferably has a viscosity (25 ° C.) of 100000 mPa · s or less from the viewpoint of good handleability. More preferably, it is 10000 mPa · s or less. From the viewpoint of excellent coatability, it is more preferably 5000 mPa · s or less.

  The composition for forming the surface layer 16 is an organic solvent such as methyl ethyl ketone, toluene, acetone, ethyl acetate, butyl acetate, methyl isobutyl ketone (MIBK), THF, DMF, etc. A solvent such as a water-soluble solvent such as methanol or ethanol may be appropriately contained. Further, it may be solventless.

  The composition for forming the surface layer 16 can be prepared by weighing various materials so as to have a desired composition and mixing them by a mixing means such as a stirrer or a sand mill. A defoaming process or the like may be performed during or after mixing.

  In order to form the surface layer 16 on the outer periphery of the base layer 14 or the outer periphery of the intermediate layer 18, a composition for forming the surface layer 16 may be applied to the surface of the base layer 14 or the intermediate layer 18. As a coating method, various coating methods such as a roll coating method, a dipping method, and a spray coating method can be applied. The coated surface layer 16 may be subjected to ultraviolet irradiation or heat treatment as necessary.

The thickness of the surface layer 16 is not particularly limited, but is preferably 0.01 to 100 μm, more preferably 0.1 from the viewpoint of preventing an increase in electrical resistance and suppressing an increase in roll hardness. It is good to be in the range of ˜20 μm, more preferably 0.3 to 10 μm. The volume resistivity of the surface layer 16 is preferably in the range of 10 ⁴ to 10 ⁹ Ω · cm, more preferably in the range of 10 ⁵ to 10 ⁸ Ω · cm, from the viewpoint of the electrical resistance controllability of the roll. And good.

  The intermediate layer 18 or the surface layer 16 may contain roughness-forming particles in order to impart an uneven shape to the roll surface and form an appropriate surface roughness. More preferably, from the viewpoint of wear resistance, long life, etc., the intermediate layer 18 may contain roughness forming particles.

  The roughness forming particles are not substantially stacked in the thickness direction of the intermediate layer 18 or the surface layer 16 from the viewpoint of uniform surface roughness, that is, the roughness forming particles are present on substantially the same plane. It is preferable.

  Examples of the roughness forming particles include urethane particles, crosslinked polymethyl methacrylate particles, acrylic particles, urea resin particles, amide particles and other resin particles, rubber particles, silica particles, and the like. These may be contained alone or in combination of two or more.

  The average particle diameter of the roughness forming particles is not particularly limited, and can be appropriately selected according to the thickness of the intermediate layer 18 and the surface layer 16. Preferably, it exists in the range of 1-50 micrometers, More preferably, it is 5-30 micrometers.

  Hereinafter, the present invention will be described in detail using examples.

<Preparation of conductive composition>
Various materials were weighed so as to have the blending ratio shown in Table 1 or Table 2 (unit is part by mass), and these were stirred and mixed with a stirrer to prepare conductive compositions according to Examples and Comparative Examples.

At this time, the various materials used are as follows.
・ Hydrine rubber (GECO) [manufactured by Nippon Zeon Co., Ltd., “Gechron 3101”]
-Acrylonitrile-butadiene rubber (NBR) [manufactured by Nippon Zeon Co., Ltd., "Nipol DN202"]
・ Dimethylaminopropylacrylamide [manufactured by Kojin Co., Ltd., “DMAPAA”]
・ Dimethylaminoethyl acrylate [manufactured by Kojin Co., Ltd., “DMAEA”]
・ Dimethylacrylamide [manufactured by Kojin Co., Ltd., “DMAA”]
・ Diethylacrylamide [made by Kojin Co., Ltd., “DEAA”]
・ Ionic conductive agent (trimethyloctadecyl ammonium perchlorate)
・ Radical polymerization initiator [Nippon Yushi Co., Ltd., “Park Mill D40”]
・ Lubricant (stearic acid)
・ Vulcanization accelerator (zinc flower)

<Material evaluation>
The material evaluation of each conductive composition was performed as follows.

<Sheet preparation conditions>
A rubber sheet sample having a thickness of 2 mm was produced by sandwiching an unvulcanized rubber material dispensed and molded to a thickness of 2.5 mm between press molds (upper mold and lower mold) and press molding at 170 ° C. for 30 minutes.

(Sheet volume resistivity)
Draw a 10 mm square electrode with a silver paste on the outer surface of a 2 mm thick press sheet (with a guard electrode). On the other hand, provide a counter electrode on the opposite surface of the sheet, and follow the method described in JIS K 6911 between the electrodes. The volume resistivity when 100 V was applied was measured.

(Ring hardness)
A measurement sample having a cylindrical shape with a diameter of 28 mm and a height of 12 mm was produced by press molding at 170 ° C. for 30 minutes, and durometer hardness (type A) (JIS-K-6253) was measured according to a conventional method.

(Blooming)
The sheet sample was allowed to stand for 7 days in an environment of 50 ° C. and 95% RH, and whether or not bloom occurred on the surface of the sheet was visually evaluated by observation with a microscope. The case where the bloom object was not visually confirmed was “◯”, and the case where the bloom object was visually confirmed was “x”.

<Preparation of conductive roll>
(Formation of base layer)
A core metal with a diameter of 6 mm is set in a metal mold having a cylindrical hole with a diameter of 12 mm, and the conductive composition is injected into the gap between the metal mold and the metal core, then both ends of the mold are sealed at 170 ° C. After heating for 30 minutes, cooling and demolding were performed to form a base layer having a thickness of 2 mm on the outer periphery of the cored bar.

(Formation of surface layer)
100 parts by mass of N-methoxymethylated nylon, 60 parts by mass of c-SnO ₂ , 1 part by mass of citric acid, and 300 parts by mass of methanol were mixed to prepare a composition for forming a surface layer. Next, the surface layer-forming composition was roll-coated on the surface of the base layer and heated at 120 ° C. for 50 minutes to form a surface layer having a thickness of 10 μm on the outer periphery of the base layer. Thereby, the conductive roll which concerns on an Example and a comparative example was produced.

<Characteristic evaluation of conductive roll>
(Image evaluation as a charging roll)
Each of the produced conductive rolls was set on a Ricoh CX3000 machine, and 10,000 character charts were imaged. In the halftone image after the endurance, “○” indicates that there is no fogging, and “X” indicates that there is a fogging.

(Bread bleedability test)
Each of the produced conductive rolls was brought into contact with a metal rod having a diameter of 30 mm in an axially parallel state, a load of 500 g was applied to both ends of the core metal of the roll (total load of 1 kg), and pressed against the metal rod at 50 ° C. X Left in a 95% RH environment for 1 week. After leaving, the load was removed and the ground contact surface with the metal rod was visually observed. At this time, “◯” indicates that no bleed component from each conductive roll was found on the ground surface, and “X” indicates that the bleed component was observed.

(Evaluation of image as developing roll)
Each of the produced conductive rolls was set in a CANON LBP-2510 machine, and images were taken out. In the half-tone image, “◯” indicates that there is no fogging, and “X” indicates that the fogging is present.

  Tables 1 and 2 summarize the composition of the composition for forming the base layer of each conductive roll and the evaluation results.

  In Comparative Example 1 and Comparative Example 4, the base layer forming composition contains an ionic conductive agent, but does not contain a radically polymerizable monomer having a tertiary amine group. For this reason, the volume resistivity of the material obtained by crosslinking the composition is increased. As a result, the image after durability by the charging roll using this as the base layer material and the image by the developing roll using this as the base layer material are deteriorated.

  In Comparative Example 2, the base layer forming composition does not contain an ionic conductive agent. Therefore, the volume resistivity of the material obtained by crosslinking the composition is high. As a result, the image after durability by the charging roll using this as the base layer material and the image by the developing roll using this as the base layer material are deteriorated.

  In Comparative Example 3, the base layer forming composition does not contain a radical polymerizable monomer having a tertiary amine group. Further, it contains more ionic conductive agent than Comparative Example 1. As a result, although the volume resistivity of the material obtained by crosslinking the composition was low, the ionic conductive agent bloomed.

  In contrast, in the examples, the base layer forming composition contains an ion conductive agent and a radical polymerizable monomer having a tertiary amine group. Therefore, the material obtained by cross-linking the composition has low resistance, and both the image after durability by the charging roll using this as the base layer material and the image by the developing roll using this as the base layer material are both good. there were. Moreover, the bloom of the ion conductive agent was not confirmed from the material which bridge | crosslinked the composition, and the bloom property was also favorable.

  In particular, when Examples 1 to 3 are compared with Comparative Example 1, even when the amount of the ionic conductive agent added is the same, the electrical resistance can be lowered by containing a radical polymerizable monomer having a tertiary amine group. It could be confirmed. Moreover, even if Example 10 and Comparative Example 4 are compared, it turns out that an electrical resistance can be similarly lowered | hung by containing the radically polymerizable monomer which has a tertiary amine group.

  Therefore, when the conductive composition according to the example is used, a conductive member for electrophotographic equipment with low resistance and suppressed bloom of the ionic conductive agent can be formed.

  As mentioned above, although embodiment of this invention was described in detail, this invention is not limited to the said Example at all, A various change is possible in the range which does not deviate from the summary of this invention.

It is a circumferential direction sectional view showing the conductive roll for electrophotographic equipment concerning one embodiment. It is a circumferential direction sectional view showing the conductive roll for electrophotographic equipment concerning one embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Conductive roll 12 for electrophotographic apparatuses Shaft body 14 Base layer 16 Surface layer 18 Intermediate layer

Claims (10)

Rubber polymer,
A radically polymerizable monomer having a tertiary amine group;
A radical polymerization initiator;
An electroconductive composition for electrophotographic equipment comprising an ionic conductive agent.   The electroconductive electrophotographic apparatus according to claim 1, wherein the radical polymerizable monomer is one or more selected from (meth) acrylamides and (meth) acrylic acid esters. Sex composition.   The radical polymerizable monomer is one or more selected from N, N-dimethylaminopropylacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, and N, N-dimethylaminoethyl acrylate. The electroconductive composition for electrophotographic equipment according to claim 1, wherein the electroconductive composition is electroconductive.   The electroconductive composition for electrophotographic equipment according to any one of claims 1 to 3, wherein the rubber polymer is a rubber polymer having a polar group.   5. The conductive composition for an electrophotographic apparatus according to claim 1, wherein the radical polymerizable monomer is contained in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the rubber polymer.   The conductive composition for electrophotographic equipment according to any one of claims 1 to 5, comprising 0.1 to 10 parts by mass of the ionic conductive agent with respect to 100 parts by mass of the rubber polymer.   The electroconductive composition for electrophotographic equipment according to any one of claims 1 to 6, wherein a mass ratio of the radical polymerizable monomer to the ionic conductive agent is in a range of 0.1 to 100.   A conductive cross-linked product for an electrophotographic apparatus, wherein a rubber polymer is co-crosslinked with a radically polymerizable monomer having a tertiary amine group and contains an ionic conductive agent.   A conductive cross-linked body for an electrophotographic apparatus, wherein the composition according to claim 1 is co-cross-linked.   An electroconductive member for an electrophotographic apparatus, wherein the cross-linked product according to claim 8 or 9 is used.

Images