JP2009075434A - Conductive composition for electrophotographic equipment, conductive crosslinked material for electrophotographic equipment and conductive member for electrophotographic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive composition for electrophotographic equipment, for forming a conductive member for electrophotographic equipment, the member having excellent dimensional accuracy, low hardness and low resistance. <P>SOLUTION: The conductive composition contains: a liquid polymer such as liquid acrylonitrile-butadiene rubber, liquid butadiene rubber and liquid isoprene rubber; an alkylene oxide-modified (meth)acrylate such as ethylene oxide-modified (meth)acrylate; a radical polymerization initiator; and an ion conducting agent. The (meth)acrylate is preferably monofunctional. The (meth)acrylate is preferably included by 20 to 80 parts by mass with respect to 100 parts by mass of the liquid polymer. Further, the composition is crosslinked and molded to obtain a conductive member such as a conductive roll for electrophotographic equipment. <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 an electrophotographic apparatus, and conductive members 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. After that, the toner image is transferred to a recording paper, and the recording paper on which the toner image is transferred is heated and pressed to fix the toner on the recording paper, thereby forming an image.

  As charging methods for charging rolls, there are a DC charging method that facilitates energy saving and cost reduction by lowering the voltage of the power supply, and an AC / DC superimposed charging method that facilitates stable charging for higher speed and higher image quality. It has been known. The AC / DC superposed charging method can relieve image defects caused by rolls and obtain high-quality images, but has the problem of requiring two types of power supplies and increasing the power supply capacity, and AC Due to the problem of the generation of charging noise due to waves, the use of the DC charging method has recently increased for high-speed, high-quality charging rolls.

  Various materials have been studied as materials constituting conductive members such as charging rolls and developing rolls according to required performance.

  For example, in Patent Document 1, NBR rubber or hydrin rubber that is elastic at room temperature is used as a base material of a roll, and a peroxide as a cross-linking agent is added to the base rubber. A developing roll in which rubber is crosslinked to a three-dimensional network structure is disclosed.

  Patent Document 2 discloses a rubber cross-linked product in which a liquid rubber is thermally cross-linked by adding a peroxide as a cross-linking agent to a liquid rubber such as liquid butadiene rubber or liquid isoprene rubber. Examples of applications in which the properties and performance of this rubber cross-linked product are effectively exhibited include conductive rolls such as charging rolls and developing rolls used in electrophotographic equipment.

Japanese Patent Laid-Open No. 2003-263021 JP 2007-131665 A

  However, as shown in Patent Document 1, when a solid (millable) rubber that is elastic at room temperature is used as the material constituting the conductive member, the viscosity of the composition is high, and therefore when the composition is injected into a mold. High pressure is applied and distortion occurs. Along with this, there is a problem that bending or the like occurs in the molded conductive member, and the dimensional accuracy of the conductive member is deteriorated. When the dimensional accuracy of the conductive member is deteriorated, the grounding property to the photosensitive drum is deteriorated and the image is deteriorated.

  Further, since the solid (millable) rubber itself is hard, there is a problem that when it is crosslinked, the hardness is further increased and the hardness of the conductive member becomes too high.

  For example, when the conductive member is a charging roll, when the hardness of the charging roll increases, the grounding property to the photoreceptor deteriorates. For this reason, the toner remaining on the photoreceptor adheres unevenly to the roll surface, and unevenness of adhesion increases due to durability. As a result, image unevenness occurs in the endured image. Further, for example, when the conductive member is a developing roll, if the hardness of the developing roll increases, toner stress occurs and the image deteriorates.

  On the other hand, in the rubber cross-linked product of Patent Document 2, although it is said that the compression set can be reduced with low hardness, the resistance reduction required for the conductive member used in electrophotographic equipment is to be reduced. It was difficult. For example, in the case where the conductive member is a charging roll, if the resistance increases, the initial charge amount becomes insufficient, charging unevenness occurs after the initial and endurance, and the image deteriorates.

  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 having excellent dimensional accuracy, low hardness and low resistance. Another object is to provide a cross-linked body for electrophotographic equipment that forms a conductive member for electrophotographic equipment having excellent dimensional accuracy, low hardness, and low resistance. It is another object of the present invention to provide an electrophotographic apparatus conductive member having excellent dimensional accuracy, low hardness and low resistance.

  In order to solve the above problems, the electroconductive composition for electrophotographic equipment according to the present invention includes a liquid polymer, an alkylene oxide-modified (meth) acrylate, a radical polymerization initiator, and an ionic conductive agent. To do.

  At this time, as the liquid polymer, one or more selected from liquid acrylonitrile-butadiene rubber, liquid butadiene rubber, liquid isoprene rubber, and liquid styrene-butadiene rubber can be suitably shown.

  The liquid polymer is preferably a liquid polymer having a polar group.

  Furthermore, the liquid polymer is preferably a modified liquid polymer.

  At this time, the liquid polymer may be a modified liquid polymer by maleic acid modification or carboxy modification.

  The (meth) acrylate is preferably ethylene oxide-modified (meth) acrylate.

  The (meth) acrylate is preferably a monofunctional (meth) acrylate.

  And it is desirable to contain 20-80 mass parts of said (meth) acrylates with respect to 100 mass parts of said liquid polymers.

  On the other hand, the electroconductive cross-linked product for electrophotographic equipment according to the present invention is characterized in that the liquid polymer is co-crosslinked with an alkylene oxide-modified (meth) acrylate and contains an ionic conductive agent.

  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 contains a liquid polymer, an alkylene oxide-modified (meth) acrylate, a radical polymerization initiator, and an ionic conductive agent. For this reason, the viscosity is low, and distortion due to pressure rise is less likely to occur when injecting into a mold. This suppresses the occurrence of bending or the like in the formed conductive member, and is excellent in dimensional accuracy of the conductive member. In addition, the surface hardness of the formed conductive member can be kept low compared to the case where a solid polymer is contained instead of the liquid polymer. As a result, the grounding property of the conductive member to the photosensitive drum is improved and the image is improved.

  And by containing an alkylene oxide modified (meth) acrylate and an ionic conductive agent, the resistance of the formed conductive member can be reduced. Thereby, for example, when used for a charging roll, charging unevenness is suppressed and an image is improved.

  At this time, if the liquid polymer is one or more selected from liquid acrylonitrile-butadiene rubber, liquid butadiene rubber, liquid isoprene rubber, and liquid styrene-butadiene rubber, the above effects are particularly excellent.

  When the liquid polymer is a liquid polymer having a polar group, the resistance of the conductive member can be further reduced.

  Furthermore, when the liquid polymer is a modified liquid polymer, the resistance of the conductive member can be further reduced.

  At this time, the modified liquid polymer by maleic acid modification or carboxy modification is excellent in the effect of reducing the resistance of the conductive member.

  And when the said (meth) acrylate is ethylene oxide modified | denatured (meth) acrylate, the resistance reduction of an electroconductive member can be achieved further.

  Further, when the (meth) acrylate is a monofunctional (meth) acrylate, the conductive member can be made to have a lower hardness.

  And when it contains 20-80 mass parts of said (meth) acrylates with respect to 100 mass parts of said liquid polymers, it is excellent in the improvement of a dimensional accuracy, hardness, and the balance of an electrical resistance.

  On the other hand, the electroconductive cross-linked product for electrophotographic equipment according to the present invention comprises a liquid polymer co-crosslinked with an alkylene oxide-modified (meth) acrylate and containing an ionic conductive agent. In addition, the conductive crosslinked body for electrophotographic equipment according to the present invention is obtained by co-crosslinking the conductive composition. Therefore, if this is used, it is possible to form an electrophotographic apparatus conductive member having excellent dimensional accuracy, low hardness and low resistance.

  And the electroconductive bridge | crosslinking body is used for the electroconductive member for electrophotographic apparatuses which concerns on this invention. Therefore, it has low hardness, low resistance, and excellent dimensional accuracy.

  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 liquid polymer, (meth) acrylate, a radical polymerization initiator, and an ionic conductive agent. ing.

  The liquid polymer is a compound having a relatively small molecular weight, and exhibits rubber elasticity by performing a crosslinking reaction. The liquid polymer is not particularly limited as long as it is liquid at room temperature and exhibits elasticity by crosslinking, such as liquid rubber.

  Since the conductive composition according to the present invention contains a liquid polymer, the viscosity is lower than that of a composition containing only a solid polymer. Therefore, when a conductive member is molded using this, distortion due to an increase in pressure hardly occurs when the conductive composition is injected into the mold. If it does so, it will suppress that bending etc. generate | occur | produce in the formed electroconductive member. A conductive member that is less likely to bend is excellent in dimensional accuracy.

  In addition, when the polymer contained in the composition before cross-linking and curing is a liquid polymer, the hardness in the state before cross-linking and curing is suppressed to a low level as compared with a composition containing only a solid polymer. The hardness of the state can be lowered.

  It is even better if the liquid polymer has a polar group. When it has a polar group, it is excellent in the effect of reducing resistance. In addition, the effect of lowering resistance is easily exhibited by the ionic conductive agent. Examples of the polar group include a chloro group, a nitrile group, a carboxyl group, an acid anhydride group, a hydroxyl group, a (meth) acryloyl group, and an alkylene oxide.

  The polar group may be a polar group contained in the liquid polymer itself, or may be a polar group introduced by modification. That is, the liquid polymer may be a modified liquid polymer.

  Examples of the modification include maleic acid modification, carboxy modification, hydroxy modification, (meth) acryl modification, and the like. If the liquid polymer is a modified liquid polymer, the resistance can be further reduced. In particular, when the liquid polymer is a liquid polymer having no polar group such as liquid butadiene rubber or liquid isoprene rubber, the resistance can be reduced by introducing the polar group into the liquid polymer by modification.

  Specific examples of the liquid polymer include liquid acrylonitrile-butadiene rubber (liquid NBR), liquid butadiene rubber (liquid BR), liquid isoprene rubber (liquid IR), liquid styrene-butadiene rubber (liquid SBR), and carboxy-modified. Liquid acrylonitrile-butadiene rubber, carboxy-modified liquid butadiene rubber, hydroxy-modified liquid butadiene rubber, (meth) acryl-modified liquid butadiene rubber, maleic acid-modified liquid isoprene rubber, carboxy-modified liquid isoprene rubber, hydroxy-modified liquid isoprene rubber, (meth) acrylic Examples thereof include a modified liquid isoprene rubber. You may use these 1 type or in mixture of 2 or more types.

  More preferably, liquid acrylonitrile-butadiene rubber (liquid NBR), carboxy modified liquid butadiene rubber, (meth) acryl modified liquid butadiene rubber, maleic acid modified liquid isoprene rubber, carboxy modified liquid isoprene rubber, (meth) acryl modified liquid isoprene rubber. It is.

  The molecular weight of the liquid polymer is not particularly limited, but a liquid polymer having a number average molecular weight in the range of 2000 to 60000 is preferable as a liquid at normal temperature.

  The (meth) acrylate contained in the conductive composition co-crosslinks between polymers having polar groups. When the (meth) acrylate is co-crosslinked between polymers having a polar group, the resulting cross-linked body has improved resistance to sag as the cross-linking density increases. That is, it is speculated that by adding (meth) acrylate and reacting with a polymer having a polar group, the crosslinking efficiency is increased, the crosslinking density is increased, and the sag resistance is improved.

  (Meth) acrylate is alkylene oxide-modified (meth) acrylate. Since (meth) acrylate is modified with alkylene oxide, the resistance of a crosslinked product using the same can be reduced. In addition, the effect of lowering resistance is easily exhibited by the ionic conductive agent.

  Examples of the alkylene oxide modification include ethylene oxide modification, propylene oxide modification, tetramethylene oxide modification, copolymerization modification thereof, and the like. Of these, ethylene oxide modification, propylene oxide modification, and ethylene oxide-propylene oxide modification are more preferable from the viewpoint of lower resistance. Particularly preferred is ethylene oxide modification.

  The (meth) acrylate preferably has 1 to 3 (meth) acryloyl groups in one molecule. That is, it is preferably monofunctional, bifunctional, or trifunctional. When the number of (meth) acryloyl groups contained in one molecule is 4 or more, the number of functional groups co-crosslinking a polymer having a polar group is contained in one (meth) acrylate molecule, Hardness tends to be high. From the above viewpoint, monofunctional (monofunctional) (meth) acrylates are more preferable. If it is monofunctional (monofunctional) (meth) acrylate, the hardness of a crosslinked body can be maintained at low hardness.

  When (meth) acrylate is co-crosslinked between polymers having polar groups, (meth) acrylate is disposed between the polymers having polar groups, and a relatively large hanging structure is formed between the polymers having polar groups. It is presumed that this suppresses aggregation (crystallization) between polar polymers and suppresses an increase in hardness of the crosslinked product.

  Specific examples of the alkylene oxide-modified (meth) acrylate include, for example, propylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, poly Tetramethylene glycol di (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, ethylene oxide-propylene oxide (block type) modified bisphenol A di (meth) acrylate, ethoxylated trimethylolpropane di (meth) acrylate, phenoxy polyethylene glycol (Meth) acrylate, phenoxypropylene glycol (meth) acrylate, ethylene oxide modified bisphenol A di (Meth) acrylate, propylene oxide modified bisphenol A di (meth) acrylate, nonylphenol ethylene oxide modified (meth) acrylate, nonylphenol propylene oxide modified (meth) acrylate, ethylene oxide modified glycerol tri (meth) acrylate, propylene oxide modified glycerol tri (meta) ) An acrylate etc. can be illustrated. These may be used alone or in combination.

  The lower limit of the content of (meth) acrylate is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and further preferably 50 parts by mass or more with respect to 100 parts by mass of the polymer having a polar group. And good. When the content of (meth) acrylate is less than 20 parts by mass, the effect of reducing resistance tends to be small.

  On the other hand, the upper limit of the content of (meth) acrylate is preferably 80 parts by mass or less, more preferably 70 parts by mass or less with respect to 100 parts by mass of the polymer having a polar group. When the content of (meth) acrylate exceeds 80 parts by mass, (meth) acrylate tends to bleed and the appearance of the product tends to deteriorate.

  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 contained in the conductive composition makes it easy to adjust the electric resistance of the crosslinked product of the conductive composition. Also, 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 lower limit of the content of the ionic conductive agent is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more with respect to 100 parts by mass of the polymer having a polar group. On the other hand, the upper limit of the content of the ionic conductive agent 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.

  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 of various additives such as a filler, an electronic conductive agent, a dispersant, an antifoaming agent, a pigment, and a release agent may be contained.

  The conductive composition may contain a solid polymer as long as the properties of the present invention are not impaired. Examples of the solid polymer include solid (millable) rubber such as acrylonitrile-butadiene rubber (NBR) and hydrin rubber (CO, ECO, GCO, GECO) which are usually used.

  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 a conductive roll used in a state where it is pressed against a photosensitive drum or the like with a constant load, such as a charging roll or 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 electroconductive cross-linked product for electrophotographic equipment according to the present invention (hereinafter sometimes referred to as electroconductive cross-linked product) contains an ionic conductive agent, and the liquid polymer is co-crosslinked with an alkylene oxide-modified (meth) acrylate. Become. The kind of liquid polymer and (meth) acrylate should just be mentioned above. Moreover, the kind and content of an ionic conductive agent should just be a kind and content mentioned above.

  In the conductive crosslinked body according to the present invention, the liquid polymer may be co-crosslinked with an alkylene oxide-modified (meth) acrylate, and the method of co-crosslinking is not particularly limited. 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.

  Moreover, in the electroconductive composition which forms an electroconductive bridge | crosslinking body, you may contain 1 type (s) or 2 or more types of the above-mentioned various additives as needed.

  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.

  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 liquid polymer is used as a main material for forming the base layer 14. As the liquid polymer, the liquid polymer described above may be used. The composition forming the base layer 14 contains an alkylene oxide-modified (meth) acrylate in order to co-crosslink the liquid polymer as the main material. 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. As the alkylene oxide-modified (meth) acrylate, the above-described alkylene oxide-modified (meth) acrylate may be used.

  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.

  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 hydrin rubber (CO, ECO, GCO, 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, fluorine rubber, natural rubber (NR), acrylonitrile-butadiene rubber (NBR), hydrogenated acrylonitrile-butadiene rubber (H -NBR), and the like. These may be used alone or in combination.

  As the rubber elastic material, silicone rubber, acrylonitrile-butadiene rubber (NBR), hydrin rubber (CO, ECO, GCO, GECO), urethane elastomer and the like are preferable from the viewpoints of electric resistance controllability, sag 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), a solvent, 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), and applying a composition dissolved in a solvent to a roll coating method Alternatively, coating may be performed by various coating methods such as dipping method and spray coating method (coating method). 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.
-Liquid acrylonitrile-butadiene rubber (liquid NBR) [manufactured by JSR Corporation, "N280"]
・ Liquid isoprene rubber (liquid IR) [manufactured by Kuraray Co., Ltd., “LIR-30”]
・ Liquid butadiene rubber (liquid BR) [manufactured by Kuraray Co., Ltd., “LIR-300”]
Solid acrylonitrile-butadiene rubber (solid NBR) [manufactured by JSR Corporation, “N250SL”]
-Ethylene oxide (EO) modified acrylate (1) (monofunctional, molecular weight Mw = 482) [manufactured by NOF Corporation, "Blemmer AME"]
Propylene oxide (PO) modified acrylate (monofunctional, molecular weight Mw = 826) [Nippon Yushi Co., Ltd., “Blemmer AP800”]
-Ethylene oxide (EO) modified acrylate (2) (bifunctional, molecular weight Mw = 742) [manufactured by Shin-Nakamura Chemical Co., Ltd., “A-600”]
-Ethylene oxide (EO) -propylene oxide (PO) modified methacrylate (bifunctional, molecular weight Mw = 1180) [manufactured by NOF Corporation, "Blemmer 43PDBPE-800B"]
-Butylene oxide (BO) modified methacrylate (bifunctional, molecular weight Mw = 490) [Nippon Yushi Co., Ltd., “Blemmer PDT800”]
・ Ionic conductive agent (trimethyloctadecyl ammonium perchlorate)
・ Radical polymerization initiator [Nippon Yushi Co., Ltd., “Park Mill D40”]

<Material evaluation>
After blending each component in Table 1, the mixture was stirred and mixed with a stirring blade for 5 minutes, and degassed under reduced pressure to prepare each conductive composition. Thereafter, this conductive composition was subjected to press crosslinking at 160 ° C. for 30 minutes to form a crosslinked sample (diameter 29 mm, thickness 12.5 mm, cylindrical shape). Using this crosslinked sample, material evaluation of each conductive composition was performed as follows.

(Ring hardness)
The measurement was performed according to JIS K 6253.

(Compression set)
According to JIS K 6262, measurement was performed at a compression rate of 25%, a test temperature of 70 ° C., and a test time of 22 hours.

(Volume resistivity)
A sheet having a thickness of 2 mm was produced by press crosslinking at 160 ° C. for 30 minutes, and the volume resistivity when 100 V was applied in accordance with the double ring electrode method described in JIS K 6271 was measured.

<Preparation of conductive roll>
(Formation of base layer)
A cored bar made of a metal shaft having a diameter of 6 mm was prepared, and after applying an adhesive to the outer peripheral surface, each conductive composition was injected into a mold in which the cored bar had been inserted in advance, and 160 ° C. × 30 minutes. Under the conditions, heat crosslinking was performed to prepare a base roll in which a conductive elastic layer (thickness 3 mm) was formed on the outer peripheral surface of the cored bar.

(Formation of surface layer)
On the outer peripheral surface of the conductive elastic layer, 50 parts by mass of a fluorine-modified acrylate resin (Dainippon Ink Industries, Ltd., “Defensor TR230K”) and a fluorine-modified acrylate resin (Atofina Japan Co., Ltd., “Kyner SL”). “) 50 parts by mass and 100 parts by mass of conductive titanium oxide (Ishihara Techno Co., Ltd.,“ Typaque ET-300W ”) were dissolved in 200 parts by mass of MEK, and these were dispersed and prepared using a sand mill. After applying the surface layer material by dipping method and drying, heating is performed under the conditions of 150 ° C. × 60 minutes to form a surface layer (thickness 6 μm), whereby the conductive rolls according to Examples and Comparative Examples are formed. Produced.

<Characteristic evaluation of conductive roll>
(Dimensional accuracy)
Rotate each base roll produced above in the circumferential direction, and measure the outer diameter run-out at three locations (both ends and center) of the roll using a laser outer diameter measuring instrument with reference to a gauge installed in parallel with the roll. The maximum value was taken as the dimensional accuracy.

(Chargeability)
Each of the produced conductive rolls is incorporated into a commercially available laser printer (“Laser Jet 4240”, manufactured by Hewlett-Packard Co., Ltd.) and imaged in a 15 ° C. × 10% RH environment to evaluate the image quality. It was. In the evaluation, “◯” indicates that no image unevenness, streaks, spots, etc. are observed, and “X” indicates that image defects such as image unevenness, streaks, spots, etc. are observed.

  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, solid NBR is used as the main material. Therefore, the viscosity of the composition is increased and the compression set is large, and as a result, the dimensional accuracy of the conductive roll is poor. In addition, the hardness of the material is high. Furthermore, since it does not contain alkylene oxide modified (meth) acrylate and ionic conductive agent, it has high resistance. Thereby, it is inferior also in charging property.

  In Comparative Examples 2 to 4, since a liquid polymer is used as the main material, it has low hardness and excellent dimensional accuracy, but does not contain an alkylene oxide-modified (meth) acrylate and an ionic conductive agent, and thus has high resistance. Poor chargeability.

  In Comparative Example 5, an ionic conductive agent is contained, but since the alkylene oxide-modified (meth) acrylate is not contained, the resistance is high and the charging property is inferior.

  In contrast, in the examples, the base layer forming composition contains a liquid polymer, an alkylene oxide-modified (meth) acrylate, a radical polymerization initiator, and an ionic conductive agent. Therefore, the compression set at the time of shaping | molding was small, and it has confirmed that it was excellent in the dimensional accuracy of the obtained electroconductive roll. Further, it was confirmed that the hardness was low and the resistance was low, and the charging property was excellent. Therefore, by using the conductive composition according to the example, it is possible to form a conductive member for electrophotographic equipment having excellent dimensional accuracy, low hardness, and low resistance.

  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 (11)

A liquid polymer;
Alkylene oxide modified (meth) acrylate,
A radical polymerization initiator;
An electroconductive composition for electrophotographic equipment comprising an ionic conductive agent.   2. The electron according to claim 1, wherein the liquid polymer is one or more selected from liquid acrylonitrile-butadiene rubber, liquid butadiene rubber, liquid isoprene rubber, and liquid styrene-butadiene rubber. Conductive composition for photographic equipment.   The electroconductive composition for an electrophotographic apparatus according to claim 1, wherein the liquid polymer is a liquid polymer having a polar group.   The electroconductive composition for electrophotographic equipment according to any one of claims 1 to 3, wherein the liquid polymer is a modified liquid polymer.   The electroconductive composition for electrophotographic equipment according to any one of claims 1 to 4, wherein the liquid polymer is a liquid polymer modified by maleic acid modification or carboxy modification.   The electroconductive composition for electrophotographic equipment according to claim 1, wherein the (meth) acrylate is ethylene oxide-modified (meth) acrylate.   The electroconductive composition for an electrophotographic apparatus according to claim 1, wherein the (meth) acrylate is a monofunctional (meth) acrylate.   The electroconductive composition for electrophotographic equipment according to any one of claims 1 to 7, comprising 20 to 80 parts by mass of the (meth) acrylate with respect to 100 parts by mass of the liquid polymer.   A conductive cross-linked product for electrophotographic equipment, wherein the liquid polymer is co-crosslinked with an alkylene oxide-modified (meth) acrylate and contains an ionic conductive agent.   A conductive crosslinked body for an electrophotographic apparatus, wherein the conductive composition according to claim 1 is co-crosslinked.   An electroconductive member for an electrophotographic apparatus, wherein the electroconductive crosslinked body according to claim 9 or 10 is used.

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