JP6576709B2 - Conductive member for electrophotographic equipment - Google Patents

Description

  The present invention relates to a conductive member for electrophotographic equipment.

  In electrophotographic apparatuses such as copying machines, printers, and facsimiles that employ an electrophotographic system, conductive rolls such as a charging roll, a developing roll, a transfer roll, and a toner supply roll are disposed around the photosensitive drum. Further, an endless belt (conductive belt) such as an intermediate transfer belt or a paper transfer conveyance belt is provided. These conductive members include a conductive elastic body layer made of an elastic body having conductivity.

JP 2005-115204 A

  In an electronic conductive system in which an electronic conductive agent is blended, there are problems of increased hardness and deterioration due to blended conductive particles. In addition, resistance unevenness due to poor dispersion of the conductive particles to be blended occurs, and there is a problem of deterioration in charging property. In an ionic conductive system in which an ionic conductive agent is blended, a polar polymer is required for the expression of ionic conductivity, and the higher the polarity, the harder and the elasticity of the polymer decreases.

  The problem to be solved by the present invention is to provide a conductive member for electrophotographic equipment which has a lower hardness and a lower sag than the prior art and is excellent in chargeability.

  In order to solve the above problems, a conductive member for an electrophotographic apparatus according to the present invention includes two or more kinds of polymers, and includes a conductive elastic layer composed of two phases of a conductive phase and a non-conductive phase, The gist is that the area ratio of the conductive phase is within a range of 10 to 90% within an arbitrary range of 5 μm □ of the conductive elastic layer.

The conductive member for an electrophotographic apparatus according to the present invention desirably has a resistance in the range of 1 × 10 ² to 1 × 10 ⁹ Ω when 10 V is applied. It is desirable that the conductive phase is a phase containing a base polymer and an electronic conductive agent, and the specific surface area of the electronic conductive agent is in the range of 150 to 1500 m ² / g. It is desirable that the area ratio of the conductive phase is within a range of 20 to 80% within an arbitrary range of 5 μm □ of the conductive elastic layer.

  According to the conductive member for an electrophotographic apparatus according to the present invention, the conductive elastic body layer is composed of two phases of a conductive phase and a non-conductive phase. Unsatisfactory, low hardness and low sag are exhibited. Then, both phases are uniformly dispersed (finely dispersed) at the toner size level such that both the conductive phase and the non-conductive phase are present in a predetermined ratio within an arbitrary range of 5 μm □ of the conductive elastic layer. Therefore, lower hardness and lower sag are exhibited. Further, charge control at the toner size level is possible, resistance unevenness is suppressed, and excellent chargeability is exhibited.

At this time, when the resistance when 10 V is applied is in the range of 1 × 10 ² to 1 × 10 ⁹ Ω, the hardness required for the electrophotographic apparatus conductive member is secured, and the low hardness and low sag are ensured. Easy to be satisfied.

And when the conductive phase is a phase containing a base polymer and an electronic conductive agent, the specific surface area of the electronic conductive agent is in the range of 150 to 1500 m ² / g, and an electronic conductive agent having a relatively large specific surface area is used, Since the electronic conductive agent is more excellent in conductive performance, the blending amount of the electronic conductive agent necessary for obtaining desired conductivity can be reduced, and low hardness and low sag are easily secured.

  When the area ratio of the conductive phase is within the range of 20 to 80% within an arbitrary range of 5 μm □ of the conductive elastic layer, the resistance unevenness is further suppressed and the chargeability is excellent.

It is the external appearance schematic diagram (a) of the electroconductive apparatus roll for electrophotographic equipment which concerns on one Embodiment of this invention, and its AA sectional view (b). They are the external appearance schematic diagram (a) of the electroconductive apparatus electroconductive belt (endless belt) which concerns on one Embodiment of this invention, and its BB sectional drawing (b). It is the schematic diagram which showed the method of measuring the area ratio of both the phases of a conductive phase and a nonconductive phase in a conductive elastic body layer. It is the schematic diagram which showed an example of the particle | grain shape of an electronic electrically conductive agent, and is a particle | grain (a) close | similar to a spherical shape with a comparatively small specific surface area, and a particle | grain (b) with a large surface irregularity and a non-spherical shape and a comparatively large specific surface area . 3 is an enlarged cross-sectional photograph of a conductive elastic layer of Example 2.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The electroconductive member for electrophotographic equipment according to the present invention (hereinafter sometimes referred to as the present electroconductive member) includes a conductive elastic layer made of an elastic body having conductivity. This conductive member is a conductive roll such as a charging roll, a developing roll, a transfer roll, and a toner supply roll used in an electrophotographic apparatus such as a copying machine, a printer, and a facsimile that employs an electrophotographic method, an intermediate transfer belt, paper It is suitable as an endless belt (conductive belt) such as a transfer conveyance belt.

  FIG. 1 shows a conductive roll for an electrophotographic apparatus according to an embodiment of the present invention, and FIG. 2 shows a conductive belt (an endless belt) for an electrophotographic apparatus according to an embodiment of the present invention. .

  As shown in FIG. 1, a conductive roll 10 for electrophotographic equipment according to an embodiment of the present invention (hereinafter simply referred to as a conductive roll 10) is disposed on a shaft body 12 and on the outer periphery of the shaft body 12. The conductive elastic body layer 14 is provided. The conductive elastic layer 14 is a base layer of the conductive roll 10, and a resistance adjustment layer, a surface layer, and the like may be provided on the outer periphery of the conductive elastic layer 14 as necessary.

  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.

  As shown in FIG. 2, a conductive belt (endless belt) 20 for electrophotographic equipment (hereinafter sometimes simply referred to as a conductive belt 20) according to an embodiment of the present invention includes a conductive elastic layer 24. . The conductive elastic layer 24 is a base layer of the conductive belt 20, and a surface layer or the like may be provided on the outer periphery of the conductive elastic layer 24 as necessary.

  In the present conductive member such as the conductive roll 10 and the conductive belt 20, the conductive elastic body layer contains two or more kinds of polymers and is composed of two phases of a conductive phase and a non-conductive phase.

  The conductive phase contains at least a base polymer composed of one or more of the two or more polymers. The base polymer may be a polar polymer, a nonpolar polymer, or a combination of a polar polymer and a nonpolar polymer. From the viewpoint of conductivity, it is preferable that the base polymer is a polar polymer or partially contains the polar polymer. When the base polymer is a polar polymer, or includes a part of the polar polymer, the conductive phase may have a conductive agent dispersed in the base polymer as long as the desired conductivity is satisfied. It need not be distributed. As the conductive agent, an ionic conductive agent or an electronic conductive agent is used according to a conductive system (ionic conductive system or electronic conductive system). From the viewpoint of easily obtaining desired conductivity, it is preferable that the conductive agent is dispersed. When the base polymer is a nonpolar polymer or includes a part of the nonpolar polymer, it is preferable that the conductive phase has a conductive agent dispersed in the base polymer as long as the desired conductivity is satisfied. .

The conductive phase is preferably made of a composition having a volume resistivity of 1 × 10 ⁸ Ω · cm or less from the viewpoint of conductivity. More preferably, the volume resistivity is 1 × 10 ⁶ Ω · cm or less, and still more preferably, the volume resistivity is 1 × 10 ⁵ Ω · cm or less. The volume resistivity of the composition constituting the conductive phase can be measured in a 23 ° C., 53% RH environment in accordance with JIS K 6911 using a sheet sample obtained by molding into a sheet shape. Moreover, it is preferable that a conductive phase consists of a composition containing a electrically conductive agent from an electroconductive viewpoint.

  The non-conductive phase contains at least a base polymer composed of one or more of the two or more polymers. The base polymer may be a polar polymer, a nonpolar polymer, or a combination of a polar polymer and a nonpolar polymer as long as it becomes a nonconductive phase. From the viewpoint of conductivity, it is preferable that the base polymer is a nonpolar polymer or a part of the nonpolar polymer. As long as the non-conductive phase becomes a non-conductive phase, the conductive agent may be dispersed in the base polymer, but from the viewpoint of conductivity, it is preferable that the conductive agent is not dispersed in the base polymer. If the electronic conductive agent is blended only in the conductive phase without blending in the non-conductive phase, the amount of the electronic conductive agent necessary for the desired conductivity can be reduced by the amount not blended in the non-conductive phase that does not function as the conductive phase. it can. Thereby, it is easy to make it low hardness and low cost.

  The nonconductive phase preferably has a higher volume resistivity than the conductive layer from the viewpoint of conductivity. The volume resistivity of the composition constituting the non-conductive phase is 23 ° C., 53 in accordance with JIS K 6911, using a sheet-like sample obtained by molding into a sheet shape, similarly to the composition constituting the conductive phase. It can be measured in a% RH environment. Moreover, it is preferable that a nonelectroconductive phase consists of a composition which does not contain a electrically conductive agent from an electroconductive viewpoint.

  In the conductive elastic layer, the conductive phase has an increase in hardness, a decrease in elastic recovery rate, and a deterioration in compression set due to the blended electronic conductive agent (conductive particles). In addition, there is uneven resistance (deterioration of chargeability) due to poor dispersion of the blended electronic conductive agent (conductive particles). There is also a reduction in elasticity due to the polar polymer used. Therefore, when the conductive elastic layer is composed of only the conductive phase, low hardness and low sag are not satisfied.

  The non-conductive phase has a smaller amount of conductive agent than the conductive phase or no conductive agent. Also, the amount of polar polymer used is less than that of the conductive phase, or no polar polymer is used. For this reason, it is relatively excellent in flexibility. Then, the conductive elastic body layer is composed of two phases of a conductive phase and a non-conductive phase, and the presence of the non-conductive phase exhibits low hardness and low sag that cannot be obtained only by the conductive phase. . And as both the conductive phase and the non-conductive phase are finely dispersed, lower hardness and lower sag are exhibited.

  The conductive elastic layer composed of two phases of the conductive phase and the non-conductive phase has an area ratio of the conductive phase within a range of 10 to 90% within an arbitrary range of 5 μm □ (5 μm × 5 μm). Moreover, the area ratio of a nonelectroconductive phase becomes in the range of 90 to 10%. Arbitrary means any place. The area ratio of both the conductive phase and the non-conductive phase is within an arbitrary range of 5 μm □. Specifically, as shown in FIG. 3, an arbitrary cross section of the conductive elastic layer is observed. Then, an arbitrary 40 × 40 μm range in the cross section is divided into 64, 16 squares arranged in a diagonal direction with diagonal lines are selected, and the area ratio of the conductive phase (non-conductive phase) within each 5 × 5 μm square is determined. Each of the 16 squares measured and selected is a value corresponding to 14 squares or more (8.5% or more).

  In the conductive elastic layer, both phases are uniformly dispersed (finely dispersed) at the toner size level so that both phases of the conductive phase and the non-conductive phase are present in a predetermined ratio within an arbitrary range of 5 μm □. Therefore, charge control at the toner size level is possible, and excellent chargeability is exhibited. If the area ratio of the conductive phase is less than 10% within an arbitrary range of 5 μm □, the ratio of the non-conductive phase is too large and the dispersibility of the conductive phase is poor. For this reason, the dispersibility of the electronic conductive agent in the conductive elastic layer is poor due to the influence of the aggregation (dispersibility) of the electronic conductive agent in the conductive phase. Thereby, resistance nonuniformity arises and charging property worsens. If the area ratio of the conductive phase is more than 90% within an arbitrary range of 5 μm □, the ratio of the conductive phase is too large and the conductive phase is not dispersed in the toner size level. For this reason, the dispersibility of the electronic conductive agent in the conductive elastic layer is poor due to the influence of the aggregation (dispersibility) of the electronic conductive agent in the conductive phase. Thereby, resistance nonuniformity arises and charging property worsens.

  When the area ratio of the conductive phase is in the range of 20 to 80% within an arbitrary range of 5 μm □ of the conductive elastic layer, the chargeability is further improved. Further, from the viewpoint of excellent chargeability, the area ratio of the conductive phase is more preferably in the range of 30 to 70%, and still more preferably in the range of 40 to 60%.

  Thus, in order to uniformly disperse (finely disperse) both the conductive phase and the non-conductive phase at the toner size level, for example, a dispersing agent that improves the dispersibility of both the conductive phase and the non-conductive phase is used. It is conceivable to use a method such as adjusting the blending ratio of the matrix polymer of the conductive phase and the matrix polymer of the non-conductive phase, or sufficiently kneading to a desired degree of dispersion.

The conductive member preferably has a resistance in the range of 1 × 10 ² to 1 × 10 ⁹ Ω when 10 V is applied. It is easy to satisfy low hardness and low sag while ensuring the conductivity required for the electroconductive member for electrophotographic equipment. Low hardness and low sag are affected by an electronic conductive agent, a polar polymer, and the like that are blended to reduce resistance. From the viewpoint of conductivity, the resistance when 10 V is applied is more preferably 1 × 10 ⁷ Ω or less, and even more preferably 1 × 10 ⁶ Ω or less. From the viewpoint of low hardness and low sag, the resistance when 10 V is applied is more preferably 1 × 10 ³ Ω or more, and further preferably 1 × 10 ⁴ Ω or more.

  The polar polymer is a polymer having a polar group. Examples of the polar group include a chloro group, a nitrile group, a carboxyl group, and an epoxy group. Examples of the polar polymer include hydrin rubber, nitrile rubber (NBR), urethane rubber (U), acrylic rubber (a copolymer of acrylic ester and 2-chloroethyl vinyl ether, ACM), and chloroprene rubber (CR). Examples of hydrin rubber include epichlorohydrin homopolymer (CO), epichlorohydrin-ethylene oxide binary copolymer (ECO), epichlorohydrin-allyl glycidyl ether binary copolymer (GCO), epichlorohydrin-ethylene oxide-allyl glycidyl ether ternary. A copolymer (GECO) etc. are mentioned. These may be used alone as a polar polymer, or may be used in combination of two or more. Among these, hydrin rubber and nitrile rubber (NBR) are preferable from the viewpoint of lower resistance.

  Nonpolar polymers are rubbers that do not have polar groups. Examples of the polar group include a chloro group, a nitrile group, a carboxyl group, and an epoxy group. Nonpolar polymers include natural rubber (NR), isoprene rubber (IR), hydrogenated isoprene rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), butyl rubber (IIR), ethylene-propylene rubber (EPM), Examples thereof include ethylene-propylene-diene terpolymer rubber (EPDM) and silicone rubber (Q). These may be used alone as a nonpolar polymer, or may be used in combination of two or more. Among these, natural rubber and isoprene rubber are preferable from the viewpoint of low hardness and easy reduction.

  Examples of the dispersant include a polymer having a block composed of a polar polymer component and a block composed of a nonpolar polymer component, a modified natural rubber, a modified isoprene rubber, and the like. Examples of the block made of a polar polymer component include a block made of a nitrile rubber component (NBR component). Examples of the block made of a nonpolar polymer component include a block made of an isoprene rubber component (IR component). Examples of such a polymer include a polymer having a block composed of a nitrile rubber component and a block composed of an isoprene rubber component. Examples of the modified natural rubber include epoxidized natural rubber, chlorinated natural rubber, and nitrified natural rubber (acrylonitrile natural rubber). Examples of the modified isoprene rubber include epoxidized isoprene rubber, chlorinated isoprene rubber, nitrified isoprene rubber (acrylonitrile-ized isoprene rubber), maleic acid-modified isoprene rubber, and (meth) acrylic acid-modified isoprene rubber. These may be used alone as a dispersant, or may be used in combination of two or more. Among these, epoxidized natural rubber and epoxidized isoprene rubber are particularly preferable from the viewpoint of particularly excellent dispersion effect.

  Examples of the ionic conductive agent include quaternary ammonium salts, quaternary phosphonium salts, borates, and surfactants. The content of the ionic conductive agent in the conductive phase of the ionic conductive system is preferably in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the base polymer of the conductive phase, from the viewpoints of low resistance and bleeding. . More preferably, it exists in the range of 0.5-5.0 mass parts.

  The electronic conductive agent is composed of conductive particles. For this reason, the specific surface area affects the conductive performance. As shown in FIG. 4A, for example, when the particles 1a and 1b have small surface irregularities and are nearly spherical and have a relatively small specific surface area, the conduction paths of the particles 1a and 1b are close to each other as indicated by dotted lines. However, as shown in FIG. 4B, for example, when the particles 2a and 2b have a large surface irregularity and a nonspherical shape and a relatively large specific surface area, the conduction path between the particles 2a and 2b is indicated by a dotted line. There are multiple locations (3 locations) in close proximity. Then, those having a relatively large specific surface area are more excellent in conductive performance in the same particle size range. Therefore, from the viewpoint of conductive performance, it is preferable to use an electronic conductive agent having a relatively large specific surface area. When the specific surface area increases, the electron conductive agent aggregates and the dispersibility tends to decrease. In the present conductive member, the conductive phase itself in which the electron conductive agent is dispersed is highly dispersed (finely dispersed) in the conductive elastic layer, so that the electron conductive agent is dispersed in the conductive elastic layer. The influence of aggregation of the conductive agent is small, and an electronic conductive agent having a large specific surface area can be highly dispersed in the conductive elastic layer.

The specific surface area of the electronic conductive agent is preferably 150 m ² / g or more from the viewpoint of conductive performance (low resistance) and the like. More preferably, it is 180 m < ² > / g or more, More preferably, it is 500 m < ² > / g or more. Moreover, it is preferable that it is 1500 m < ² > / g or less from a viewpoint of suppressing aggregation in a conductive phase and being excellent in dispersibility. More preferably, it is 1400 m < ² > / g or less, More preferably, it is 1200 m < ² > / g or less. In order to obtain desired conductivity, the electronic conductive agent has a higher specific surface area when the electronic conductive agent has a specific surface area of 150 to 1500 m ² / g and a relatively large specific surface area. The amount of the electronic conductive agent necessary for the process can be reduced, and it is easy to ensure low hardness and low sag.

  In the range of the specific surface area, the content of the electronic conductive agent in the conductive phase of the electronic conductive system is 6 parts by mass or more with respect to 100 parts by mass of the base polymer of the conductive phase from the viewpoint of conductivity (low resistance). Preferably there is. More preferably, it is 7 mass parts or more, More preferably, it is 8 mass parts or more. Further, from the viewpoint of low hardness and low sag, it is preferably 40 parts by mass or less with respect to 100 parts by mass of the base polymer of the conductive phase. More preferably, it is 35 mass parts or less, More preferably, it is 30 mass parts or less.

  Examples of the electronic conductive agent include carbon black, graphite, potassium titanate, iron oxide, conductive titanium oxide, conductive zinc oxide, and conductive tin oxide. Among these, carbon black and graphite are preferable from the viewpoint of conductivity and the like.

  The conductive rubber elastic layer is formed from a conductive composition containing at least a composition constituting a conductive phase and a composition constituting a non-conductive phase. This electroconductive composition may contain the said dispersing agent. Moreover, this electroconductive composition contains a vulcanizing agent (crosslinking agent), a vulcanization accelerator, a vulcanization auxiliary agent (crosslinking auxiliary agent) and the like as necessary. Further, one or more additives such as a bulking agent, a reinforcing agent, a processing aid, an antioxidant, a plasticizer, an ultraviolet absorber, and a lubricant can be contained.

  The conductive composition comprises a composition constituting a conductive phase, a composition constituting a non-conductive phase, and the dispersant, vulcanizing agent (crosslinking agent), vulcanization accelerator, which are blended as necessary. It is prepared by blending and kneading vulcanization aid (crosslinking aid), additives and the like. The composition constituting the conductive phase is prepared by mixing and kneading the matrix polymer with the conductive agent and additives blended as necessary before preparing the conductive composition. In addition, the composition constituting the non-conductive phase is also prepared by mixing and kneading the matrix polymer and an additive added as necessary before preparing the conductive composition.

  The blending ratio of the matrix polymer (a) of the conductive phase and the matrix polymer (b) of the non-conductive phase is from the viewpoint that both the conductive phase and the non-conductive phase are easily dispersed (finely dispersed) at the toner size level. The mass ratio is preferably a / b = 10/90 to 90/10. More preferably, it is in the range of a / b = 20/80 to 80/20, and further preferably in the range of a / b = 30/70 to 70/30.

  The blending amount of the dispersant is such that the conductive phase matrix polymer (a) and the non-conductive phase matrix polymer are easily dispersed (finely dispersed) at the toner size level. It is preferable that it exists in the range of 0.1-20 mass parts with respect to a total of 100 mass parts of (b). More preferably, it exists in the range of 0.5-15 mass parts, More preferably, it exists in the range of 1.0-10 mass parts.

  Examples of the vulcanizing agent (crosslinking agent) include sulfur and peroxide. Among the vulcanizing agents (crosslinking agents), a peroxide is more preferable from the viewpoint of being easily lowered. The amount of the peroxide is 0.5 to 7 masses with respect to a total of 100 mass parts of the matrix polymer (a) of the conductive phase and the matrix polymer (b) of the non-conductive phase, from the viewpoint of easy reduction. It is preferably within the range of parts. More preferably, it exists in the range of 1.0-5 mass parts.

The conductive elastic layer is excellent in conductivity, and satisfies low hardness and low sag. From the viewpoint of conductivity, the resistance value of the conductive elastic body layer is preferably in the range of 1.0 × 10 ^{2 to} 1.0 × 10 ⁹ Ω. Moreover, it is preferable that MD-1 hardness of a conductive elastic body layer is 50 or less from a viewpoint of lower hardness than before. More preferably, it is 45 or less and 40 or less. From the viewpoint of lowering than before, the elastic recovery rate of the conductive rubber elastic layer is preferably 80% or more. More preferably, it is more than 80%, 85% or more, 90% or more. The MD-1 hardness is measured using a cantilever-type leaf spring type spring type hardness tester (manufactured by Kobunshi Keiki Co., Ltd., “Micro Rubber Hardness Tester MD-1 Type”). The MD-1 hardness measurement value is a value measured with a thickness of the polymer to be measured of 1 to 2 mm. The elastic recovery rate is measured using a microhardness meter (Fischer, Fischerscope H100C) in accordance with ISO14577-1.

  Although the thickness of a conductive elastic layer is not specifically limited, Usually, it forms in about 0.1-10 mm, Preferably it is 1-5 mm. The conductive elastic layer may be a solid non-foamed material or a foamed material such as a sponge.

  The conductive roll 10 can be manufactured as follows, for example. First, an adhesive composition is applied to the outer periphery of the shaft body 12 as necessary. Next, the conductive composition is formed into a layer on the outer periphery of the applied adhesive composition. The conductive composition can be molded by extrusion molding or molding. The conductive composition is crosslinked and cured by heating at the time of extrusion molding or molding. Thereby, the electroconductive roll 10 which has the electroconductive elastic body layer 14 in the outer periphery of the shaft body 12 is obtained.

  The outer periphery of the conductive elastic layer 14 is provided with surface characteristics (low friction, releasability, chargeability, etc.) of the conductive roll 10 to protect the surface of the conductive elastic layer 14 as necessary. For the purpose of, for example, a surface layer may be formed. Further, an intermediate layer such as a resistance adjusting layer for adjusting the resistance of the entire conductive roll 10 may be formed below the surface layer on the outer periphery of the conductive elastic layer 14.

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

The surface layer, 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 and surfactants can be appropriately added. Moreover, you may add various additives suitably as needed.

  In order to form the surface layer, a surface layer forming composition is used. The composition for surface layer formation consists of what contains the said main material, a electrically conductive agent, and the other additive contained as needed. Additives include lubricants, vulcanization accelerators, anti-aging agents, light stabilizers, viscosity modifiers, processing aids, flame retardants, plasticizers, foaming agents, fillers, dispersants, antifoaming agents, pigments, release agents. Examples include molds.

  From the viewpoint of adjusting the viscosity, the surface layer-forming composition is an organic solvent such as methyl ethyl ketone, toluene, acetone, ethyl acetate, butyl acetate, methyl isobutyl ketone (MIBK), THF, or DMF, or a water-soluble solution such as methanol or ethanol. A solvent such as a reactive solvent may be included as appropriate.

  The surface layer can be formed by a method such as coating the surface-forming composition on the outer periphery of the conductive elastic layer 14. 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 may be subjected to ultraviolet irradiation or heat treatment as necessary.

The thickness of the surface layer is usually set to 0.01 to 100 μm, 0.1 to 20 μm, or 0.3 to 10 μm. The volume resistivity of the surface layer is usually set to 10 ⁴ to 10 ⁹ Ω · cm, 10 ⁵ to 10 ⁸ Ω · cm, or 10 ⁶ to 10 ⁷ Ω · cm.

  Further, instead of forming the surface layer, surface modification may be performed on the intermediate layer such as the conductive elastic layer 14 or the resistance adjusting layer, so that the surface characteristics equivalent to the formation of the surface layer can be obtained. . Surface modification methods include UV or electron beam irradiation, surface layer unsaturated bonds and surface modifiers that can react with halogens, such as isocyanate groups, hydrosilyl groups, amino groups, halogen groups, thiol groups, etc. Examples thereof include a method of contacting with a compound containing a reactive group.

  The conductive belt 20 is formed by coating a conductive composition on the surface of a mold (cylindrical substrate) by a coating method such as spray coating, and heating the coating to a predetermined temperature (preferably 150 to 300 ° C.). It can be formed by drying for a time (preferably 3 to 6 hours). The outer periphery of the conductive elastic layer 24 is provided with surface characteristics (low friction, releasability, chargeability, etc.) of the conductive belt 20 that protect the surface of the conductive elastic layer 24 as necessary. For the purpose of, for example, a surface layer may be formed. Examples of the surface layer material include silicone resins, fluorine resins, urethane resins, acrylic resins, polyamide resins, and the like.

  As mentioned above, although embodiment of this invention was described in detail, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of this invention. For example, in FIG. 1, the conductive elastic layer is shown as the base layer of the conductive roll, but may be a surface layer. Similarly, in FIG. 2, the conductive elastic layer is shown as the base layer of the conductive belt, but it may be a surface layer.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to this structure.

Details of the materials used are shown below.
Nitrile rubber (NBR): JSR "N237H"
Isoprene rubber (IR): “JSR IR2200” manufactured by JSR
・ Dispersant: Block copolymer of NBR and IR ・ Ionic conductive agent: Tetrabutylammonium bromide, “TBAB-100” manufactured by Lion Akzo Co., Ltd.
Carbon black (1) (Electronic conductive agent) “Printex XE2B” manufactured by Degussa, BET specific surface area 950 (m ² / g)
Carbon black (2) (electronic conductive agent): “Blackpearls 2000” manufactured by Cabot, BET specific surface area 1475 (m ² / g)
Carbon black (3) (electronic conductive agent): “Special Black 4” manufactured by Degussa, BET specific surface area 180 (m ² / g)
・ Peroxide vulcanizing agent: “Park Mill D40” manufactured by NOF Corporation

(Examples 1-10, Comparative Examples 1-2)
<Preparation of conductive composition>
Each component was mix | blended with the compounding composition (mass ratio) shown in Table 1, and it stirred and mixed with the stirrer and prepared the electrically conductive composition.

<Preparation of conductive roll>
A core metal (diameter 6 mm) is set on the center axis of a molding die having a cylindrical molding cavity of 9 mm in diameter, and the conductive composition is injected into the molding die, and heated and crosslinked at 160 ° C. for 30 minutes. After cooling and demolding, a conductive elastic layer having a thickness of 1.5 mm was formed on the outer periphery of the cored bar. This produced the electroconductive roll.

  About the electroconductive elastic body layer of each obtained electroconductive roll, the area ratio of an electroconductive phase and a nonelectroconductive phase, an elastic recovery rate, MD-1 hardness, and resistance value were measured. In addition, product characteristics such as setability, initial and durable fogging, and image density were evaluated. The set property is affected by the sagability of the conductive elastic layer. The initial fogging property is affected by charging properties (area ratio of two phases of the conductive elastic layer). The durability fogging property is affected by the hardness of the conductive elastic layer. The image density is affected by the resistance value (conductivity) of the conductive elastic layer. As a representative example, a cross-sectional photograph of the conductive elastic layer of the conductive roll of Example 2 is shown in FIG. In FIG. 5, the relatively dark portion is the non-conductive phase, and the relatively light portion is the conductive phase. In the lower right of FIG. 5, a scale (5 μm) is shown for indicating the size of both phases.

(Area ratio)
As shown in FIG. 3, an arbitrary cross section of the conductive elastic layer is observed, an arbitrary 40 × 40 μm range in the cross section is divided into 64, and 16 cells arranged in a diagonal direction with diagonal lines are selected, The area ratio of the conductive phase and the non-conductive phase within each 5 × 5 μm square was measured, and 14 squares or more (8.5% or more) out of 16 squares were the corresponding values.

(Elastic recovery rate)
In accordance with ISO14577-1, the surface of the conductive elastic layer was measured under the following measurement conditions using a microhardness meter (Fischer scope H100C, manufactured by Fischer), and ηIT [%] was determined. That is, when a microhardness meter is used and the indenter is pushed into the material surface with a constant test load, the total mechanical work Wtotal shown in the indentation work is very small as the plastic deformation work amount Wplast of the indentation. Only part is consumed. When the test load is unloaded, the remaining part is released as the elastic return deformation work Welast of the recess. If this mechanical work is defined as W = ∫Fdh, the relationship is as follows. The elastic recovery rate was 80% or more low, and less than 80% high.
ηIT [%] = Welast / Wtotal
However, Wtotal = Welast + Wplast
<Measurement conditions>
Indenter: Square-angled diamond indenter with a face angle of 136 ° Initial load: 0 mN
Maximum indentation load: 20mN (constant load)
Maximum load arrival time: 0.25 to 10 sec
Maximum load holding time: 5 sec
Drawing time: 0.25-10sec
Measurement temperature: 25 ° C

(MD-1 hardness (micro rubber hardness))
Conductive elasticity of each conductive roll held using a cantilever-type leaf spring type spring type hardness tester (manufactured by Kobunshi Keiki Co., Ltd., “Micro Rubber Hardness Tester MD-1”) Measurement was performed by bringing the tip of the push needle of the hardness tester into contact with the surface of the center portion in the axial direction of the body layer, further pressing the tester vertically with a load of 33.85 g, and immediately reading the scale. . An MD-1 hardness of 50 or less was defined as low hardness, and a hardness exceeding 50 was defined as high hardness.

(Resistance value)
With the both ends of the conductive roll pressed against the metal roll (diameter: 30 mm) with a predetermined load, the conductive roll was rotated by rotating the metal roll at a predetermined rotation speed. While maintaining this state (while rotating both the metal roll and the conductive roll), a voltage of 10 V is applied between the ends of the conductive roll and the metal roll, the value of the flowing current is measured, and the electric resistance value (roll Resistance: Ω) was obtained. When the resistance value exceeds 1 × 10 ⁹ Ω, the resistance is high, and when the resistance value is in the range of 1 × 10 ² Ω to 1 × 10 ⁹ Ω, the resistance is low.

(Set property)
The conductive roll was assembled to the cartridge, sealed, and left in a normal temperature and humidity environment for 14 days. Thereafter, the image was printed in a normal temperature and humidity environment. The case where a streak-like defect was seen in the drawing was judged as “failed” “x”, and the case where it was not seen was judged as “passed”. Further, the roundness of the conductive elastic layer was measured with Roncom, and the amount of sag from the dent amount from the roundness was measured. A case where the amount of sag was 5 μm or less was regarded as low, and a case where the amount was more than 5 μm was regarded as high. Of the acceptable “◯” in the setting property, the case where the amount of sag was 2 μm or less was particularly good “◎”.

(Initial fogging)
A conductive roll was assembled in the cartridge, and a white solid image was printed. The density was measured with a white photometer, and the initial fog was good “◯” if it was within the range of 1.40 to 1.46 at any nine points, and it was judged as “bad” if it was outside the range. Among the good initial fogging “◯”, those with white light intensity in the range of 1.43 to 1.45 at any nine points were particularly good “◎”.

(Durable fogging)
The conductive roll was assembled in the cartridge, and allowed to stand for 12 hours or more in a low-temperature and low-humidity environment (15 ° C., humidity 10%). Then, in this environment, 10,000 sheets were endured with 5% printing. Thereafter, the density was measured with a white photometer, and if any nine points were in the range of 1.40 to 1.46, the durability fogging was good “◯”, and if it was out of the range, it was judged as “poor”. Among the “◯” with good durability fogging, those with white light intensity in the range of 1.43 to 1.45 at any nine points were particularly good “「 ”.

(Image density)
A conductive roll was assembled in the cartridge, and a black solid image was printed. The density was measured with a white photometer, and if it was within the range of 1.0 to 2.0 at any nine points, it was judged as “good”, and if it was out of the range, it was judged as “bad”. Among the images with good image density “◯”, those with white light intensity in the range of 1.3 to 1.6 at any 9 points were rated particularly good “「 ”.

  In Comparative Example 1, the area ratio of the conductive phase is large in an arbitrary range of 5 μm □ of the conductive elastic layer, and the conductive phase is not dispersed in the toner size level. For this reason, the dispersibility of the electronic conductive agent in the conductive elastic layer is poor due to the influence of the aggregation (dispersibility) of the electronic conductive agent in the conductive phase. As a result, resistance unevenness occurs, charging property is poor, and initial fogging is not satisfactory. In Comparative Example 2, the area ratio of the conductive phase is small in the arbitrary range of 5 μm □ of the conductive elastic layer, and the conductive phase is not uniformly dispersed. For this reason, the dispersibility of the electronic conductive agent in the conductive elastic layer is poor due to the influence of the aggregation (dispersibility) of the electronic conductive agent in the conductive phase. As a result, resistance unevenness occurs, charging property is poor, and initial fogging is not satisfactory.

  On the other hand, in the embodiment, the area ratio of the conductive phase is within a desired range in an arbitrary range of 5 μm □ of the conductive elastic layer, and both the conductive phase and the non-conductive phase are at the toner size level as shown in FIG. Is uniformly dispersed (finely dispersed), the dispersibility of the conductive agent in the conductive elastic layer is excellent, and the charging property is excellent. Thereby, initial fogging is satisfied. In addition, since it has a low hardness, a low sag, and a low resistance, it also satisfies setability, image density and durability fogging.

  And from Examples 2, 9, and 10, as the BET specific surface area of the electronic conductive agent to be blended increases, the amount of the electronic conductive agent required to obtain the same resistance value can be reduced, and the hardness and the hardness can be lowered. Can be. Or it can be made lower resistance with the same compounding quantity. Further, from Examples 2 to 6, when the area ratio of the conductive phase is within the range of 20 to 80% in the arbitrary range of 5 μm □ of the conductive elastic layer, the initial fogging property is particularly excellent.

  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.

DESCRIPTION OF SYMBOLS 10 Conductive roll 12 for electrophotographic apparatuses Shaft body 14 Conductive elastic body layer 20 Conductive belt 24 for electrophotographic apparatuses Conductive elastic body layer

Claims (4)

A conductive elastic layer is provided, and the conductive elastic layer contains two or more types of base polymers constituting the conductive elastic layer, and is composed of one or more of the two or more types of base polymers. A conductive phase containing at least a base polymer and a non-conductive phase containing at least a base polymer composed of one or more of the two or more base polymers ;
A conductive member for an electrophotographic apparatus, wherein an area ratio of the conductive phase is within a range of 10 to 90% within a range of 5 μm × 5 μm square at any location of the conductive elastic layer. ^{2. The} electroconductive member for electrophotographic equipment according to claim 1, wherein a resistance when 10 V is applied is in a range of 1 × 10 ² to 1 × 10 ⁹ Ω. The electron according to claim 1 or 2, wherein the conductive phase is a phase containing a base polymer and an electronic conductive agent, and the specific surface area of the electronic conductive agent is in a range of 150 to 1500 m ² / g. Conductive member for photographic equipment. 4. The method according to claim 1, wherein an area ratio of the conductive phase is in a range of 20 to 80% in a range of 5 μm × 5 μm square everywhere in the conductive elastic layer. The electroconductive member for electrophotographic equipment according to item.