JP2007310230A - Conductive roll and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive roll having minute recesses and projections that are more uniform than those of a conventional one, and to provide a manufacturing method therefor. <P>SOLUTION: The conductive roll has an outermost layer on its outermost circumference. The outermost layer is formed from a hard substance comprising a UV-curing composition containing an ultraviolet polymeric monomer and/or ultraviolet polymeric oligomer, ultraviolet polymerization initiator, and an ultraviolet transmission reducing substance. The surface of the outermost layer has minute recesses and projections. The outermost layer of the conductive roll can be manufactured by irradiating a coating layer formed from the UV-curing composition with ultraviolet light, and then curing the coating layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a conductive roll and a method for producing the same, and more particularly to a conductive roll suitable for use in an electrophotographic apparatus and the like and a method for producing the same.

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

  In the electrophotographic apparatus, recently, methods such as a contact development method and a contact charging method have become mainstream. In these methods, for example, a developing roll and a charging roll are used as follows.

  That is, in the contact development method, the surface of the developing roll on which the toner layer is formed is brought into direct contact with the surface of the photosensitive drum, thereby causing the toner to adhere to the latent image on the surface of the photosensitive drum.

  In the contact charging method, the surface of the charging roll is brought into direct contact with the surface of the photosensitive drum, and the surface of the photosensitive drum is charged by discharging the charging roll.

  Therefore, when a conductive roll is used as a developing roll, excellent toner transportability is required, and when it is used as a charging roll, excellent discharge characteristics are required.

  In order to satisfy these required characteristics, conventionally, the surface of a roll has been roughened in a conductive roll such as a developing roll or a charging roll.

  For example, Patent Document 1 is a document relating to a developing roll, which discloses a developing roll whose surface is roughened by dispersing silica particles in the outermost resin layer of the roll. Yes.

  Further, for example, Patent Document 2 is a document relating to a charging roll. In this document, there is a charging roll in which a rubber layer is coated with a polyurethane resin on the outer periphery of the rubber layer after the surface of the rubber layer is polished and roughened. It is disclosed.

  In addition, for example, Patent Document 3 is a document related to the developing roll. In this document, after applying a coating liquid containing a urethane-based ultraviolet curable resin to the outer peripheral surface of the elastic layer, ultraviolet rays having different strengths are used. A developing roll having a resin coating layer having a surface provided with fine irregularities by irradiating a plurality of times is disclosed. It can be said that the technique according to this document creates fine irregularities only under ultraviolet irradiation conditions.

This document mentions that if fine particles are dispersed in the resin coating layer, the light transmittance is lowered and the ultraviolet curability is impaired, so that such fine particles should not be actively used. ing.
JP 2002-296897 A (paragraph 0002, paragraph 0034, etc.) JP-A-9-160354 (Claims etc.) Japanese Unexamined Patent Application Publication No. 2004-354489 (Claims, Paragraph 0015, Example 1)

  However, when the conventionally known roughening technique is applied to roughen the roll surface of the conductive roll, there are the following problems.

  That is, roughness-forming particles such as silica particles tend to aggregate before coating or when the outermost layer is formed. Therefore, it is difficult to obtain uniform surface irregularities by the method using roughness forming particles. Therefore, due to this, toner transportability is likely to be lowered in the developing roll, and discharge characteristics are lowered in the charging roll, and it is difficult to charge the photosensitive drum.

  Further, the roughness-forming particles form surface irregularities using the particle size. For this reason, the hard convex portion protruding from the surface of the layer tends to deteriorate the counterpart material such as the toner or the photosensitive drum. For this reason, image quality is likely to deteriorate during long-term use.

  On the other hand, when the surface of the outermost layer is roughened using an abrasive, it is difficult to obtain uniform surface irregularities in the first place, and defective products are more likely to occur due to adhesion of polishing powder to the surface. In addition, toner or a toner external additive (such as silica) is likely to be clogged in the recesses locally formed during polishing. For this reason, image quality is likely to deteriorate during long-term use.

  According to the experiments by the present inventors, it is difficult to obtain sufficient irregularities even when the ultraviolet ray curable resin containing no fine particles is irradiated twice with ultraviolet rays having different intensities. The control range was also narrow.

  As described above, the roughened state of the conductive roll surface greatly affects the roll performance. Therefore, a new surface roughening technique capable of forming more uniform fine irregularities is desired.

  Therefore, the problem to be solved by the present invention is to provide a conductive roll capable of forming uniform fine irregularities as compared with the conventional one, and a method for producing the same.

  In order to solve the above problems, the conductive roll according to the present invention includes an outermost layer on the outermost periphery of the roll, and the outermost layer includes an ultraviolet polymerizable monomer and / or an ultraviolet polymerizable oligomer, an ultraviolet polymerization initiator, and an ultraviolet ray. It is made of a cured product of an ultraviolet curable composition containing at least a transmission reducing substance, and the gist is that the surface of the outermost layer has fine irregularities.

  Here, the outermost layer is preferably subjected to at least one kind of crosslinking selected from isocyanate crosslinking, peroxide crosslinking, and electron beam irradiation crosslinking.

  The ultraviolet curable composition preferably further contains an organic polymer that does not have ultraviolet curable properties.

  On the other hand, the method for producing a conductive roll according to the present invention applies an ultraviolet curable composition containing at least an ultraviolet polymerizable monomer and / or an ultraviolet polymerizable oligomer, an ultraviolet polymerization initiator, and an ultraviolet transmission reducing substance. The first step of forming the coating layer and the second step of irradiating the coating layer with ultraviolet rays to cure the coating layer and form the outermost layer having fine irregularities on the surface. And having a process.

  Moreover, the said manufacturing method may further have the 3rd process which performs a bridge | crosslinking process with respect to the said outermost layer.

  In the conductive roll according to the present invention, when ultraviolet light is irradiated to the uncured ultraviolet curable composition at the time of forming the outermost layer, the ultraviolet light incident on the composition due to the presence of the ultraviolet light transmission reducing substance. The degree of arrival of changes in the thickness direction. Therefore, a difference occurs in the curability of the composition between the layer surface and the inside. And using this, it becomes possible to form relatively uniform and fine irregularities on the layer surface when the composition is cured.

  According to the conductive roll, uniform fine irregularities can be formed on the outermost surface without using hard roughness-forming particles.

  Therefore, dispersion variation due to roughness-forming particles does not occur as in the prior art, and toner transportability does not decrease when used as a developing roll, and discharge characteristics do not decrease when used as a charging roll. . Therefore, good toner transportability, chargeability, etc. can be exhibited.

  Further, due to the hard roughness-forming particles, the mating material such as the toner and the photosensitive drum is not deteriorated, and the toner or the like is not clogged in a local concave portion generated by polishing. Therefore, it is easy to maintain a good image quality over a long period of time, and the durability is excellent.

  Here, when the outermost layer has been subjected to at least one or more types of crosslinking selected from isocyanate crosslinking, peroxide crosslinking, and electron beam irradiation crosslinking, by the secondary curing, Fewer uncured parts.

  Moreover, when the said ultraviolet curable composition contains further the organic polymer which does not have ultraviolet curing property, since a hardening component becomes relatively few, an uncured part can be decreased.

  On the other hand, in the method for producing a conductive roll according to the present invention, when the coating layer formed in the first step is irradiated with ultraviolet rays in the second step, the composition is reduced by the ultraviolet transmission reducing substance in the ultraviolet curable composition. The degree of arrival of ultraviolet rays incident on the object changes in the thickness direction. Therefore, a difference occurs in the curability of the composition between the layer surface and the inside. When the composition shrinks and cures, fine irregularities are generated on the surface of the layer, and as a result, an outermost layer having relatively uniform and fine irregularities is formed.

  Therefore, according to the manufacturing method of the said conductive roll, the conductive roll which concerns on this invention with the said effect can be obtained.

  In addition, according to the above-described method for producing a conductive roll, it is possible to impart roughness to the outermost layer surface mainly by using a composition of an ultraviolet curable composition, and there are also advantages such as a relatively wide control range of fine irregularities. is there.

  At this time, when the formed outermost layer is subjected to a crosslinking treatment, uncured portions in the outermost layer can be reduced by secondary curing.

  Hereinafter, the conductive roll according to the present embodiment (hereinafter sometimes referred to as “main roll”) and the method for manufacturing the conductive roll according to the present embodiment (hereinafter also referred to as “present manufacturing method”). This will be described in detail.

1. Main roll The main roll has a specific outermost layer on the outermost periphery of the roll. Specifically, if this roll has one layer, this layer corresponds to the outermost layer of this roll. Moreover, if this roll has a laminated structure in which two or more layers are laminated, the layer located on the outermost circumference of the roll corresponds to the outermost layer of this roll.

  The specific configuration of the roll is, for example, the outer periphery of a conductive shaft (a metal core made of a solid metal, a metal cylinder hollowed out inside, or a metal plated body thereof) The outer shaft has one outermost layer, or one or more inner layers (for example, a conductive elastic layer) on the outer periphery of the shaft, and the outermost layer (for example, a film) on the outer periphery. Examples of the configuration can be given.

  In the present roll, the outermost layer is made of a cured product of a specific ultraviolet curable composition. Hereinafter, the ultraviolet curable composition will be described.

  The ultraviolet curable composition contains at least an ultraviolet polymerizable monomer and / or an ultraviolet polymerizable oligomer, an ultraviolet polymerization initiator, and an ultraviolet transmission reducing substance.

  The said ultraviolet polymerizable monomer means the monomer which has ultraviolet bondability and has an unsaturated bond. The ultraviolet polymerizable monomer may be composed of one or more monomers.

  In the molecular structure of the ultraviolet polymerizable monomer, for example, an alkylene oxide unit such as ethylene oxide or propylene oxide, a trimethylolpropane unit, a pentaerythritol unit, an ethylhexyl carbitol unit, a glycerin unit, a nonylphenol unit, a paracumylphenol unit, It is preferable to have one or more units such as a bisphenol A unit, a styrene oxide unit, an isocyanuric acid unit, a bisphenol F unit, a phthalic acid unit, and a phenoxy unit.

  In addition, the ultraviolet polymerizable monomer has, for example, a functional group such as an acryloyl group, a methacryloyl group, an allyl group, a vinyl group, a thiol group, a vinyl ether group, an epoxy group, a glycidyl ether group, and other groups having an intramolecular double bond. It is good to have one or two or more.

  More specifically, examples of the ultraviolet polymerizable monomer include, for example, trimethylolpropane ethylene oxide-modified triacrylate, polyethylene glycol diacrylate, methoxy polyethylene glycol monomethacrylate, polyethylene glycol dimethacrylate, 2-ethylhexyl carbitol monoacrylate, polyethylene glycol monoacrylate. Ethyl ether monomethacrylate, ethoxylated cyclohexane dimethacrylate, ethoxylated 2-methyl-1,3-propanediol diacrylate, ethoxylated polypropylene glycol dimethacrylate, ethoxylated glycerin triacrylate, ethoxylated pentaerythritol tetraacrylate, phenoxy polyethylene glycol mono Acrylate, paracumylphenoxy Tylene glycol monoacrylate, paracumylphenol ethylene oxide modified monoacrylate, bisphenol A diacrylate, bisphenol A ethylene oxide modified diacrylate, propoxyethoxybisphenol A diacrylate, 9,9-bis (3-phenyl-4-acryloylpolyoxyethoxy) fluorene And ethoxylated isocyanuric acid triacrylate, nonylphenoxypolyethylene glycol monoacrylate, and the like. These may be contained alone or in combination of two or more.

  Among these ultraviolet-polymerizable monomers, preferably, two or more of polyethylene glycol diacrylate, bisphenol A ethylene oxide-modified diacrylate, and the like, from the viewpoint of relatively large shrinkage during ultraviolet curing and easy formation of fine irregularities. Those having a functional group can be suitably used.

  The said ultraviolet polymerizable oligomer means the oligomer which has an ultraviolet bondability and has an unsaturated bond. The ultraviolet polymerizable oligomer may be composed of one or more kinds of oligomers.

  In the molecular structure of the ultraviolet polymerizable oligomer, for example, alkylene oxide units such as ethylene oxide and propylene oxide, trimethylolpropane units, pentaerythritol units, ethylhexyl carbitol units, glycerin units, nonylphenol units, paracumylphenol units, It is preferable to have one or more units such as a bisphenol A unit, a styrene oxide unit, an isocyanuric acid unit, a bisphenol F unit, a phthalic acid unit, a phenoxy unit, and a urethane bond unit.

  In addition, the ultraviolet polymerizable oligomer has functional groups such as acryloyl group, methacryloyl group, allyl group, vinyl group, thiol group, vinyl ether group, epoxy group, glycidyl ether group, and other groups having an intramolecular double bond. It is good to have one or two or more.

  More specifically, examples of the ultraviolet polymerizable oligomer include, for example, polypropylene glycol triacrylate oligomer, polyethylene polypropylene glycol diacrylate oligomer, polyethylene glycol diacrylate oligomer, polycarbonate acrylic oligomer, and polytetramethylene glycol diacrylate. Examples include oligomers, polycaprolactone diacrylate oligomers, polyester acrylate oligomers, polyurethane acrylate oligomers, and the like. These may be used alone or in combination.

  Among these UV-polymerizable oligomers, preferably, from the viewpoint of relatively large shrinkage during UV curing and easy formation of fine irregularities, a polyethylene glycol diacrylate oligomer, a polypropylene glycol triacrylate oligomer, a polyester Those having two or more functional groups such as diacrylate oligomers can be suitably used.

  In the present composition, the photoinitiator is not particularly limited, and any photoinitiator can be used as long as it can be normally used.

  Specific examples of the ultraviolet polymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, 2-methylbenzoin, benzyl, benzyldimethylketal, diphenyl sulfide, tetramethylthiuram monosulfide, Diacetyl, eosin, thionine, mihira-ketone, anthracene, anthraquinone, acetophenone, α-hydroxyisobutylphenone, p-isopropylαhydroxyisobutylphenone, α · α 'dichloro-4-phenoxyacetophenone, 1-hydroxy-1-cyclohexylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, methylbenzoyl formate, 2-methyl-1- [4- (methylthio) phenyl] .2.morpholino-propene, thioxanthone , Benzophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 1-hydroxy-cyclohexyl-phenyl-ketone, benzophenone, 2-methyl-1- [4 -(Methylthio) phenyl] -2-monforinopropanone 1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone 1,2-hydroxy-2-methyl-1-phenyl- Propan-1-one, 2,4,6-trimethylbenzoyldiphenyl-phosphine oxide, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, Bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyryl) titanium), -Hydroxy-2-methyl-1-phenylpropan-1-one, bisacylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, (η5-2,4-cyclopentadien-1-yl ) [(1,2,3,4,5,6-η)-(1-methylethyl) benzene] -iron (1 +)-hexafluorophosphate (1-) and the like. These may be used alone or in combination.

  As a preferable upper limit of the content of the ultraviolet polymerization initiator, specifically, for example, 50 parts by weight or less, 40 parts by weight or less with respect to 100 parts by weight of the organic component contained in the composition, Examples thereof include 30 parts by weight or less.

  On the other hand, as a preferable lower limit value that can be combined with these upper limit values, specifically, for example, 1 part by weight or more, 2 parts by weight or more, 3 parts by weight with respect to 100 parts by weight of the organic component contained in the composition As mentioned above, 5 parts by weight or more, 10 parts by weight or more, 10 parts by weight or more can be exemplified.

  When the content of the ultraviolet polymerization initiator is within the above range, the curing reaction due to polymerization is easily promoted and fine surface irregularities are easily formed even if an ultraviolet transmission reducing substance described later is present.

  The ultraviolet transmission reducing substance is a substance that can exhibit a function of reducing the transmittance of ultraviolet rays incident on the composition when it is dispersed in the ultraviolet curable composition (uncured). . In order to reduce the transmittance of ultraviolet rays, the ultraviolet rays may be blocked, reflected, scattered, absorbed, or the like.

  When an ultraviolet curable composition containing this ultraviolet light transmission reducing substance is formed in a layer, it is possible to change the degree of arrival of ultraviolet light incident on the composition with the ultraviolet light transmission reducing substance in the layer thickness direction. . Therefore, for example, it is possible to cause a difference in the curability of the composition between the surface of the layer and the inside, without taking measures such as irradiating ultraviolet rays with different intensities multiple times. Become.

  The form of the ultraviolet light transmission-reducing substance is not particularly limited as long as the function can be exhibited. Specifically, for example, forms such as a particulate form, a fibrous form, and a massive form can be exemplified. Preferably, it is in the form of particles from the viewpoint of being easily dispersed uniformly in the composition.

  The ultraviolet transmission reducing substance has a function different from that of the roughness-forming particles conventionally used for imparting roughness.

  Therefore, when the outermost layer is formed, the size of the UV transmission reducing substance (if the form is particulate, the particle size, if fibrous, from the viewpoint of not becoming a roughness forming factor on the outermost layer surface) Specific examples of the preferred upper limit of the minor axis) include 1 μm, 0.1 μm, 50 nm, and the like. On the other hand, specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 5 nm, 10 nm, 20 nm, and the like.

  The ultraviolet transmission reducing substance may be an inorganic substance or an organic substance as long as it can exhibit the above function. Preferably, it is an inorganic substance from the viewpoint that there are many that are easily dispersed uniformly in the composition.

  The ultraviolet transmission reducing substance may be conductive or non-conductive as long as it can exhibit the above function. In the case of imparting conductivity to the outermost layer, there is an advantage that the necessity of adding another conductive agent again is reduced. Therefore, the ultraviolet transmission reducing substance is preferably conductive.

Specific examples of the UV transmission reducing substance include carbon-based materials such as carbon black (channel black, furnace black, thermal black, acetylene black, etc.), graphite, and carbon fiber, and oxides of indium and tin. (such as ITO), titanium oxide (such as TiO _2), zinc oxide (such as ZnO), oxides of indium and zinc (IZO, etc.), aluminum oxide (such as alumina) metal oxides such or iron powder Examples thereof include metal powders. These may be contained alone or in combination of two or more.

  Of these, carbon black, oxides of indium and tin, and the like can be suitably used from the viewpoints of being excellent in the effect of reducing ultraviolet transmittance and imparting conductivity.

  The content of the ultraviolet transmission reducing substance is preferably in the range of 3 to 500 parts by weight with respect to 100 parts by weight of the organic component contained in the composition.

  However, the content of the ultraviolet transmission reducing substance is preferably determined in consideration of the ultraviolet transmission reducing effect of the substance, the thickness of the outermost layer, and the like. For example, if the effect of reducing ultraviolet transmittance is relatively large, the effect can be exhibited with a relatively small content, and if the effect of reducing ultraviolet transmittance is relatively small, It can be said that the effect is more easily achieved when the content is too large.

  More specifically, when a carbon-based material such as carbon black is used as the ultraviolet transmission reducing substance, the content is preferably a preferable upper limit value, specifically, for example, an organic contained in the composition. 200, 150, 100, 60 parts by weight and the like can be exemplified with respect to 100 parts by weight of the component.

  On the other hand, specific examples of preferable lower limit values that can be combined with these upper limit values include 3, 5, 10, and 20 parts by weight with respect to 100 parts by weight of the organic component contained in the composition. be able to.

  Further, when an oxide of indium and tin such as ITO is used as the ultraviolet light transmission reducing substance, the content is preferably a preferable upper limit value, specifically, for example, an organic component contained in the composition For example, 500, 400, 300, 200 parts by weight and the like can be exemplified with respect to 100 parts by weight.

  On the other hand, specific examples of preferable lower limit values that can be combined with these upper limit values include, for example, 80, 100, 120, 140 parts by weight and the like with respect to 100 parts by weight of the organic component contained in the composition. be able to.

  Further, when titanium oxide is used as the ultraviolet transmission reducing substance, the content thereof is preferably a preferable upper limit value, specifically, for example, with respect to 100 parts by weight of an organic component contained in the composition. Examples include 500, 400, 300, 200 parts by weight.

  On the other hand, specific examples of preferable lower limit values that can be combined with these upper limit values include 20, 50, 80, 110 parts by weight, and the like with respect to 100 parts by weight of the organic component contained in the composition. be able to.

  In addition, when zinc oxide is used as the ultraviolet transmission reducing substance, the content thereof is preferably a preferable upper limit value, specifically, for example, with respect to 100 parts by weight of an organic component contained in the composition. Examples include 500, 400, 300, 200 parts by weight.

  On the other hand, specific examples of preferable lower limit values that can be combined with these upper limit values include 20, 50, 80, 110 parts by weight, and the like with respect to 100 parts by weight of the organic component contained in the composition. be able to.

  If the content of the UV transmission reducing substance is within the above range, a difference in curability of the composition between the surface and the inside of the composition is likely to occur during the formation of the outermost layer, and fine surface irregularities are formed. Cheap.

  The weight ratio of the ultraviolet polymerization initiator to the ultraviolet transmission reducing substance (weight of the ultraviolet polymerization initiator / weight of the ultraviolet transmission reducing substance) is preferably 0.1 to 2 from the viewpoint of excellent balance of ultraviolet curing and the like. 0.0, more preferably in the range of 0.5 to 1.0.

  The ultraviolet curable composition may contain other optional components as necessary in addition to the essential components.

  Specific examples of other optional components include silicone resins, fluorine resins, polymethyl methacrylate (PMMA), polycarbonate, polyamide resins, urethane resins, nitrile rubber (NBR), and epichlorohydrin rubber. Examples thereof include organic polymers having no ultraviolet curable properties, such as rubbers, modified products obtained by modifying these resins and rubbers with silicone, fluorine, and the like. These may be contained alone or in combination of two or more.

  When these polymers are further contained, the curing component in the composition is relatively reduced, so that the uncured portion can be reduced.

  The organic polymer having no ultraviolet curable property can be contained in the composition as long as it does not hinder the formation of fine irregularities.

  The content of the organic polymer having no UV curable property is preferably a preferable upper limit value, specifically, for example, 95, 80, 70, 60% by weight in 100% by weight of the organic component in the composition. Etc. can be illustrated.

  On the other hand, specific examples of preferable lower limit values that can be combined with these upper limit values include 1, 10, 20, and 30% by weight in 100% by weight of the organic component in the composition.

  The ultraviolet curable composition includes a conductive agent (electronic and / or ionic), a crosslinking agent, a crosslinking aid, a dispersant, a light stabilizer, a surface modifier, a filler, an antifoaming agent, and a flame retardant. In addition, one or more kinds of various additives such as a viscosity modifier, an antioxidant, a processing aid, a lubricant, a plasticizer, a foaming agent, and a pigment may be contained.

  Among these, specific examples of the crosslinking agent include isocyanate crosslinking agents (MDI, TDI, HDI, TMXDI, IPDI, XDI, etc.), peroxide crosslinking agents (dialkyl peroxide, t-butyl peroxide). Examples thereof include organic peroxide crosslinking agents such as benzoate and perester, inorganic peroxide crosslinking agents, epoxy crosslinking agents, and amine crosslinking agents. These may be contained alone or in combination of two or more.

  When these cross-linking agents are contained, secondary curing is facilitated, so that the uncured portion in the outermost layer can be reduced.

  Moreover, the said ultraviolet curable composition may contain the suitable solvent from a viewpoint that coating becomes easy. Specific examples of the solvent include methyl ethyl ketone, methyl isobutyl ketone, acetone, methanol, ethanol, isopropyl alcohol, butanol, xylene, toluene, ethyl acetate, cyclohexane, butyl acetate, DMF, THF, NMP, PEGME, water, and the like. Can be illustrated. These may be used alone or in combination.

  In the case of using a solvent, specific examples of the preferable upper limit of the concentration of the non-volatile content in the composition in an uncured state include 99, 90, 80, and 70% by weight.

  On the other hand, specific examples of preferable lower limit values that can be combined with these upper limit values include 2, 4, 6, and 8% by weight.

  The method for producing the ultraviolet curable composition is not particularly limited. For example, the essential components UV-polymerizable monomer and / or UV-polymerizable oligomer, UV-polymerization initiator and UV-transmission-reducing substance, and optional components to be contained as necessary are blended in a desired blending ratio. These are mixed by mixing means such as a stirrer, or an ultraviolet light transmission reducing substance is dispersed and mixed in advance in an organic component such as an ultraviolet polymerizable monomer and / or an ultraviolet polymerizable oligomer, and the remaining mixture is mixed with the remaining mixture. A method of blending essential components and optional components and then mixing them can be exemplified.

  The outermost layer of this roll has fine irregularities on the layer surface. Specific examples of the fine uneven shape include a wrinkle shape and a protrusion shape. These may exist independently in the outermost layer surface, or both may be mixed.

  The fine irregularities can be formed by the following principle when the ultraviolet curable composition is cured.

  That is, when the ultraviolet curable composition is irradiated with ultraviolet rays at the time of forming the outermost layer, the degree of arrival of ultraviolet rays entering the composition changes in the thickness direction due to the presence of the ultraviolet transmission reducing substance. . Therefore, a difference occurs in the curability of the composition between the layer surface and the inside, and fine irregularities are formed on the layer surface as the composition is cured and contracted.

  The thickness of such an outermost layer can be appropriately selected in consideration of the intended use of the roll (developing roll, charging roll, etc.), ease of forming fine irregularities, and wear.

  Specific examples of the preferable upper limit value of the thickness of the outermost layer include 500, 400, 300, 200 μm, and the like. On the other hand, specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 0.1, 0.5, 1, and 2 μm.

  Further, the surface roughness Rz of the outermost layer is, for example, excellent discharge characteristics when used as a charging roll, and preferable upper limit value from the viewpoint of excellent toner transportability when used as a developing roll, Specifically, 100, 80, 60, 40 μm and the like can be exemplified. On the other hand, specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 1, 2, 3, 4 μm, and the like.

  The surface roughness Rz is a ten-point average roughness Rz measured in accordance with JIS B0601.

  The outermost layer of this roll has been described above. In the case where the present roll has a laminated structure, the material for forming the inner layer may be appropriately selected in consideration of the purpose of the present roll and the like.

  Specific examples of the material for forming the inner layer include those containing a conductive agent (electronic conductive agent and / or ionic conductive agent) in the following main materials.

  That is, specific examples of the main material include silicone rubber, ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), hydrogenated acrylonitrile-butadiene rubber (H-NBR), and styrene-butadiene. Rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), acrylic rubber (ACM), chloroprene rubber (CR), urethane rubber, fluorine rubber, hydrin rubber (ECO, CO), urethane elastomer, natural rubber (NR) ) And the like. These may be used alone or in combination.

  In particular, when this roll is used as a developing roll, silicone rubber, butadiene rubber, hydrin rubber, urethane elastomer, etc. are suitable as the main material from the viewpoint of low sag, conductivity, flexibility, etc. It can be illustrated as.

  Further, when this roll is used as a charging roll, hydrin rubber, nitrile rubber, urethane elastomer, silicone rubber, etc. are preferably exemplified as the main material from the viewpoint of low sag and conductivity. be able to.

When the present roll is used as a developing roll, the content of the conductive agent is usually such that the volume resistivity of the inner layer is preferably 10 ² to 10 ¹⁰ Ω · cm, more preferably 10 ⁴ to 10 ⁸ Ω · cm. What is necessary is just to adjust suitably so that it may become in the range. Moreover, when this roll is used as a charging roll, the volume resistivity of the inner layer is usually preferably in the range of 10 ² to 10 ¹⁰ Ω · cm, more preferably 10 ⁴ to 10 ⁸ Ω · cm. What is necessary is just to adjust suitably.

  In addition to the conductive agent, the material for forming the inner layer may be a filler, an extender, a reinforcing agent, a processing aid, a vulcanizing agent, a vulcanization accelerator, a crosslinking agent, a crosslinking aid, or an antioxidant, if necessary. In addition, one or more kinds of various additives such as a plasticizer, an ultraviolet absorber, a pigment, a silicone oil, a lubricant, an auxiliary agent, and a surfactant may be appropriately contained.

  The proportion of the additive may be appropriately selected from conventionally known blending proportions so that various additives can achieve their purpose. Moreover, when it has two or more inner layers, each inner layer may be the same material and composition, and a different material and composition may be sufficient as it.

  Although the thickness of the said inner layer is not necessarily limited, Usually, what is necessary is just to adjust suitably so that it may preferably become in the range of 0.1-10 mm, More preferably, it is 1-5 mm.

2. This manufacturing method This manufacturing method is a method which can manufacture this roll which has the above-mentioned composition, and includes the following 1st processes and 2nd processes at least. Hereinafter, it demonstrates in order.

2.1 First Step In this production method, the first step is a step of coating the ultraviolet curable composition to form a coating layer.

  Here, when manufacturing this roll having one layer, as the first step, specifically, for example, roll coating is performed on the surface of a conductive shaft to which an adhesive, a primer or the like is arbitrarily applied. Examples thereof include a method in which the composition is applied by a method, a dipping method, a spray coating method, and the like, and dried to form a coating layer.

  On the other hand, when manufacturing this roll having a laminated structure, the following method can be specifically exemplified as the first step. That is, the inner layer forming material is extruded on the surface of the conductive shaft, or the conductive shaft is coaxially installed in the hollow portion of the roll molding die, and the inner layer forming material is injected and heated. -After curing, remove the mold and form a roll body on which the inner layer has been formed in advance. Note that when a plurality of inner layers are formed, an operation according to the above method may be repeated.

  Then, the method of coating the said composition on the surface of the obtained roll body by a roll coating method, a dipping method, a spray coating method, etc., and making it dry and forming a coating layer etc. can be illustrated.

2.2 Second Step In this manufacturing method, the second step is to irradiate the coating layer formed through the first step with ultraviolet rays, thereby curing the coating layer and forming the outermost layer. It is a process.

  The ultraviolet irradiation may be performed once or a plurality of times. Moreover, when irradiating ultraviolet rays several times, the irradiation intensity of ultraviolet rays may be the same or different.

  However, in the second step, the ultraviolet irradiation is preferably performed once. According to this production method, since the ultraviolet curable composition is used, sufficient fine irregularities can be formed by one ultraviolet irradiation, and productivity is also improved when the number of ultraviolet irradiations is small. It is.

  Specific examples of the ultraviolet lamp used for ultraviolet irradiation include a mercury lamp, a xenon lamp, a deuterium lamp, an excimer lamp, and a metal halide lamp. These may be used alone or in combination of two or more.

The amount of ultraviolet irradiation varies depending on the thickness of the coating layer, the type of the ultraviolet polymerizable monomer and oligomer, etc., but usually, as the ultraviolet intensity to be irradiated, as a preferable upper limit, specifically, for example, 1000, 800 , 600, 400 mW / cm ^{2, and the} like.

On the other hand, specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 1, 10, 20, 30 mW / cm ^{2, and the} like.

  Further, as a preferable upper limit value of the irradiation time of ultraviolet rays, specifically, for example, 600, 500, 400, 300 seconds and the like can be exemplified.

  On the other hand, specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 0.1, 1, 5, 10 seconds, and the like.

  According to the manufacturing method, the main roll can be obtained. In addition, the present manufacturing process may include a third process for performing a crosslinking treatment on the outermost layer, for example, after the second process, if necessary.

  When the third step is further added, the uncured portion in the outermost layer can be reduced by secondary curing. Therefore, contamination of other members due to uncured portions is less likely to occur, and reliability is easily improved.

  Specific examples of the crosslinking treatment include irradiation with an electron beam and heat treatment of the outermost layer. These may be used alone or in combination of two or more.

  Hereinafter, the present invention will be described in detail using examples. The following is an example of the case where the conductive roll according to the present invention is applied to a charging roll and a developing roll.

<Composition No. used for forming the outermost layer> Preparation of 1-15>
Carbon black (acetylene black) or ITO is blended as an ultraviolet transmission reducing substance for each monomer, oligomer and polymer so as to have the blending ratio shown in Table 1, and a bead mill disperser (manufactured by Shinmaru Enterprises Co., Ltd.). , “Dynomill KDL-Pilot”) was subjected to dispersion treatment (number of rotations 3200 rpm) three times.

  Then, after blending the remaining materials in each of the obtained dispersion-treated products, the mixture was stirred and mixed with a stirrer, whereby composition No. 1 to 15 (all UV curable compositions) were prepared.

  In addition, said composition No. Preparations 1 to 15 were performed while adding a solvent (methyl ethyl ketone) as appropriate so that the concentration of the nonvolatile content was 10% by weight after the preparation.

<Composition No. used for forming the outermost layer> Preparation of ratio 1 to ratio 5>
Carbon black (acetylene black) was blended with each polymer so that the blending ratio shown in Table 2 was achieved, and the dispersion treatment (the same conditions as above) was performed three times with the bead mill disperser.

  Next, each of the obtained dispersion-treated products was blended with the remaining material (if there is no remaining material), and this was stirred and mixed with a stirrer, whereby composition No. Ratios 1 to 4 were prepared.

  In addition, said composition No. The preparation of ratio 1 to ratio 4 was performed while adding a solvent (methyl ethyl ketone) as appropriate so that the concentration of the nonvolatile content was 10% by weight after the preparation.

  On the other hand, composition no. The ratio 5 was prepared by diluting the polymer shown in Table 2 with the above solvent so that the nonvolatile content concentration was 10% by weight.

<Composition material of composition>
Each compounding material used for preparation of the composition is as follows.
(Composition No. 1-15)
・ Polypropylene glycol triacrylate oligomer (functional group number 3, Shin-Nakamura Chemical Co., Ltd., “NK Oligo UA7100”)
Bisphenol A ethylene oxide-modified diacrylate (functional group number 2, Shin-Nakamura Chemical Co., Ltd., “NK Ester A-BPE-20”)
-Bisphenol A epoxy diacrylate (2 functional groups, manufactured by Daicel UCB, "Ebecryl 3700")
-Bisphenol A hydroxydiacrylate (functional group number 2, Shin-Nakamura Chemical Co., Ltd., “NK Oligo EA1020”)
・ Phenolethylene oxide modified acrylate (functional group 1, Shin-Nakamura Chemical Co., Ltd., “NK ester AMP-60G”)
・ Isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., “Coronate C2512”)
・ Acrylic silicone (manufactured by Toagosei Co., Ltd., “Symac US270”)
・ Ultraviolet polymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd., “Irgacure 819”)
Carbon black (acetylene black, average particle size 35 nm, manufactured by Denki Kagaku Kogyo Co., Ltd., “DENKA BLACK”)
ITO (average particle size 0.1 μm, manufactured by Sumitomo Metal Mining Co., Ltd., “X100D”)
・ Organic peroxide crosslinking agent (Nippon Yushi Co., Ltd., “Perhexa V”)
・ Ionic conductive agent (trimethyloctadecyl ammonium perchlorate)
・ Surface modifier A (perfluorooctyl ethyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd., “FA108”)
(Composition No. ratio 1-5)
・ Polymethylmethacrylate A (Negami Kogyo Co., Ltd., “Hyperl M4501”)
・ Polymethylmethacrylate B (manufactured by Sumitomo Chemical Co., Ltd., “LG6A”)
・ Urethane acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., “NK Oligo UA-2235PE”)
・ Surface modifier B (silicone surface modifier, manufactured by NOF Corporation, "FS700")
Carbon black (acetylene black, average particle size 35 nm, manufactured by Denki Kagaku Kogyo Co., Ltd., “DENKA BLACK”)
・ Roughness-forming particles (PMMA particles, average particle size 15 μm, manufactured by Soken Chemical Co., Ltd., “MX1500”)
・ UV polymerization initiator ("Irgacure 819", manufactured by Ciba Specialty Chemicals Co., Ltd.)

<Characteristics of cured products obtained by curing each composition>
In order to investigate the characteristics of the cured product obtained by curing each composition, the following experiment was conducted.
That is, each composition was coated on a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc.) having a thickness of 100 μm by a bar coating method to form each coating layer.

Thereafter, composition no. About the coating layer which concerns on 1-15, using an ultraviolet irradiation machine (Igraphics Co., Ltd. make, "UB031-2", mercury lamp "H03-L021"), ultraviolet intensity 200mW / cm < ² > for 30 seconds Irradiated with ultraviolet rays.

  At this time, the composition No. For the coating layer according to No. 12, an electron beam for 30 seconds at a tube current of 200 μA and an irradiation distance of 50 mm using an EB irradiator (“Min-EB” manufactured by USHIO INC.) After irradiation with the ultraviolet rays Was irradiated.

  In addition, Composition No. 13 and no. The coating layer according to No. 14 was further subjected to heat treatment at 180 ° C. for 30 minutes using an oven (“Hi-Temp-Chamber ST120” manufactured by Nagoya Scientific Instruments Co., Ltd.) after irradiation with the ultraviolet rays.

In addition, Composition No. About the coating layer which concerns on ratio 5, after irradiating an ultraviolet-ray for 0.4 second with the ultraviolet intensity of 50 mW / cm < ² > using a mercury lamp, it was further used for the ultraviolet intensity of 200 mW / cm < ² > using a metal halide lamp. Irradiated with ultraviolet rays for 5 seconds.

  In addition, Composition No. About the coating layer which concerns on ratio 1-ratio 4, it heat-processed at 100 degreeC for 1 hour using the said oven.

  Next, the cured product of each composition thus obtained was cut, and the film thickness of each cured product was measured from the SEM photograph of the cross section. Moreover, while observing the surface state of each hardened | cured material with SEM, based on JISB0601, surface roughness (10 points | pieces, manufactured by Tokyo Seimitsu Co., Ltd., "Surfcom 1400D") is used. The average roughness (Rz) was measured.

  Tables 1 and 2 collectively show the blending ratio of each composition, the film thickness of the cured product of each composition, and the surface roughness Rz.

  According to Tables 1 and 2, the following can be understood. That is, the composition No. The ratios 1 and 3 did not have ultraviolet curability, and effective fine unevenness could not be formed on the layer surface only by heat treatment.

  In addition, Composition No. The ratio 2 and the ratio 4 are composition Nos. Like the ratio 1 and the ratio 3, it does not have ultraviolet curability, but the roughness forming particles are blended, so that it was possible to impart roughness to the layer surface. However, the site | part where roughness formation particle | grains aggregate was seen, and the uniform surface unevenness | corrugation was not obtained. In addition, these compositions had poor handling properties because the roughness-forming particles having a high specific gravity settled in the composition.

  In addition, Composition No. Ratio 5 has ultraviolet curability. However, even when the ultraviolet rays having different intensities were irradiated twice, sufficient unevenness could not be obtained, and the control range of the unevenness was narrow.

  In contrast, composition No. According to 1 to 15, uniform and fine surface irregularities could be obtained without using roughness forming particles. Further, the surface irregularities were wrinkled. In addition, depending on the blending of the ultraviolet polymerization initiator and the ultraviolet light transmission reducing substance, it was separately confirmed that, in addition to the wrinkled surface unevenness, a protruding surface unevenness was also obtained.

<Preparation of conductive roll>
Next, the prepared composition No. 1-11, composition no. Using the ratios 1 and 2, charging rolls according to Examples 1 to 11, Comparative Example 1 and Comparative Example 2 were produced. In addition, Composition No. The developing roll which concerns on Examples 12-15 and Comparative Examples 3-5 was produced using 12-15, ratio 3-ratio 5. The charging roll and the developing roll produced in this example are basically obtained by curing each of the above compositions on the surface of a base roll in which one conductive elastic layer is formed as an inner layer on the outer periphery of the core metal. A film-like outermost layer is formed. Hereinafter, a procedure for producing these charging roll and developing roll will be described.

(Charging roll)
100 parts by weight of epichlorohydrin rubber (ECO) (manufactured by Daiso Corporation, “Epichromer CG102”), 1 part by weight of stearic acid (manufactured by Kao Corporation, “Lunac S-30”), and two types of zinc oxide ( 5 parts by weight of Mitsui Kinzoku Kogyo Co., Ltd., 3 parts by weight of an acid acceptor (manufactured by Kyowa Chemical Industry Co., Ltd., “DHT-4A”), 1.5 wt. Of powder sulfur (manufactured by Tsurumi Chemical Co., Ltd.) Parts, 1.5 parts by weight of a thiazole vulcanization accelerator (Ouchi Shinsei Chemical Co., Ltd., “Noxeller DM”), and a thialium vulcanization accelerator (Ouchi Shinsei Chemical Co., Ltd., “ The forming material T of the conductive elastic layer was prepared by kneading 0.5 parts by weight of Noxeller TS ") and 1 part by weight of trimethyloctadecyl ammonium perchlorate with a kneader.

  Next, the above-prepared conductive elastic layer forming material T was injected into a roll forming mold incorporating a stainless steel core (SUS304) having a diameter of 6 mm by an injection casting machine, and then 180 ° C. in an oven. Crosslinking was carried out at 45 ° C. for 45 minutes. Thus, a base roll T having a conductive elastic layer having a thickness of 2.5 mm on the outer periphery of the cored bar was produced.

  Next, on each base roll T surface, the composition No. 1-11, composition no. The ratios 1 and 2 were applied by a roll coating method to form each coating layer.

Next, the composition No. About what coated 1-11, using the said ultraviolet irradiation machine, rotating a roll at 100 rpm, using a UV intensity of 200 mW / cm ² for 30 seconds, the composition was cured. A film-like outermost layer was formed. Thereby, the charging roll which concerns on Examples 1-11 was produced.

  In addition, Composition No. About what coated ratio 1 and ratio 2, it heat-processed for 30 minutes at 100 degreeC using the said oven, and formed the film-form outermost layer. Thereby, the charging roll which concerns on the comparative example 1 and the comparative example 2 was produced.

(Development roll)
Liquid silicone rubber (50 parts by weight of “KE1350A” manufactured by Shin-Etsu Chemical Co., Ltd. and 50 parts by weight of “KE1350B” manufactured by Shin-Etsu Chemical Co., Ltd.), carbon black (manufactured by Ketjen Black International Co., Ltd., “ EC300J ") 6 parts by weight was kneaded with a kneader to prepare a conductive elastic layer forming material G.

  Next, the above-prepared conductive elastic layer forming material G was injected into a roll molding die incorporating the cored bar by an injection casting machine, and then crosslinked in an oven at 150 ° C. for 45 minutes. Thus, a base roll G having a conductive elastic layer having a thickness of 4 mm on the outer periphery of the cored bar was produced.

  Next, after the surface of each base roll G was subjected to surface treatment by corona discharge (0.3 kW for 20 seconds), the composition No. 12-15, composition no. The ratios 3 to 5 were applied by a roll coating method to form each coating layer.

Next, the composition No. For those coated with 12-15, while rotating the roll at 100 rpm, using the above-mentioned ultraviolet irradiator, irradiated with ultraviolet rays once at an ultraviolet intensity of 200 mW / cm ² for 30 seconds to cure each composition, A film-like outermost layer was formed.

  Thereafter, composition no. For those coated with No. 12, after the irradiation of the ultraviolet rays, the outermost layer was further irradiated with a tube current of 200 μA using the EB irradiator (“Min-EB” manufactured by Ushio Electric Co., Ltd.). An electron beam was irradiated at a distance of 50 mm for 30 seconds. Thereby, a developing roll according to Example 12 was produced.

  In addition, Composition No. 13 and composition no. About what coated No. 14, after the irradiation of the said ultraviolet-ray, the outermost layer was further heat-processed at 180 degreeC for 30 minute (s) using the said oven. Thus, developing rolls according to Examples 13 and 14 were produced.

  In addition, Composition No. About what coated No. 15, it was set as the developing roll which concerns on Example 15 without performing the said electron beam irradiation and heat processing.

  In addition, Composition No. About what applied ratio 3 and ratio 4, it heat-processed for 30 minutes at 100 degreeC using the said oven, and formed the film-form outermost layer. Thereby, the developing roll which concerns on the comparative example 3 and the comparative example 4 was produced.

In addition, Composition No. For those coated with a ratio of 5, after rotating the roll at 100 rpm, using a mercury lamp and irradiating with ultraviolet rays at an ultraviolet intensity of 50 mW / cm ² for 0.4 seconds, further using a metal halide lamp, The composition was cured by irradiating ultraviolet rays at an intensity of 200 mW / cm ² for 2.5 seconds to form a film-like outermost layer. Thereby, a developing roll according to Comparative Example 5 was produced.

<Evaluation of charging roll and developing roll>
For each of the produced charging rolls and developing rolls, first, the thickness of the outermost layer, the surface roughness of the outermost layer, and the roll resistance were measured as follows.

(Outermost layer thickness)
The center in the longitudinal direction of each roll was cut, and the thickness of the outermost layer was measured from the SEM photograph of the cross section.

(Surface roughness of outermost layer)
In accordance with JIS B0601, the surface roughness (10-point average roughness Rz) of the outermost layer surface was measured using the contact-type surface roughness meter.

(Roll resistance)
A stainless metal roll (roll diameter: 30 mm) and each roll were brought into line contact, a load of 700 g was applied to both ends of the metal roll, and a direct current of 300 V was applied to both to measure the electrical resistance of each roll.

  Furthermore, in order to investigate the difference in roll performance depending on the roughened state of the roll surface, the following tests were conducted on the charge roll for discharge performance, for the development roll for toner transportability, and for both rolls for durability.

(Dischargeability)
Each charging roll was incorporated in a cartridge of a commercially available color laser printer (manufactured by Nippon Hured Packard Co., Ltd., “Laser Jet 4L”), and a voltage of 1000 V was applied. At this time, the case where the surface potential of the photosensitive drum on the first round was 300 V or higher was determined to be acceptable, and the case where the surface potential was less than 300 V was determined to be unacceptable.

(Toner transportability)
Each developing roll was incorporated in a cartridge of a commercially available color laser printer (manufactured by Canon Inc., “Laser Shot LBP-2510”), and a single sheet of white paper was printed out. Thereafter, the toner adhering to the roll surface was transferred to an adhesive tape (manufactured by Sumitomo 3M Co., Ltd., “Scotch Mending Tape”), and the toner conveyance amount per unit area was determined. The case where the toner conveyance amount was 0.80 mg / cm ² or more was determined to be acceptable, and the case where it was less than 0.80 mg / cm ² was determined to be unacceptable.

(durability)
Each charging roll and developing roll were incorporated in the cartridge of each color laser printer, and 10,000 sheets (A4 size, vertical direction) of a solid black image were printed in an environment of 23 ° C. × 50% RH.

  Thereafter, an image of a solid black image was obtained, and the obtained image was visually confirmed for the presence or absence of uneven image density. As a result, an image with no uneven image density was accepted, and an image with uneven image density was rejected.

  Tables 3 and 4 collectively show the evaluation results of each charging roll and developing roll.

  According to Table 3, the following can be understood. That is, it does not have ultraviolet curability, and composition No. In the charging roll according to Comparative Example 1 in which the outermost layer is formed by curing the ratio 1, almost no fine irregularities are formed on the outermost layer surface. Therefore, both dischargeability and durability were unacceptable.

  Moreover, the composition No. containing the roughness forming particles was used. In the charging roll according to Comparative Example 2 in which the outermost layer was formed by curing the ratio 2 only by heat treatment, image density unevenness occurred in the durability evaluation. This is presumed that the toner component is deposited at the location where the roughness forming particles are present, the electric resistance becomes non-uniform, and the image quality is lowered.

  In contrast, composition No. It was confirmed that the charging rolls according to Examples 1 to 11 in which 1 to 11 were cured with ultraviolet rays to form the outermost layer were excellent in both dischargeability and durability. This is because uniform and fine surface irregularities are formed on the surface of the outermost layer without adding roughness forming particles or polishing.

  Similarly, according to Table 4, the following can be understood. That is, it does not have ultraviolet curability, and composition No. In the developing roll according to Comparative Example 3 in which the outermost layer is formed by curing the ratio 3, almost no fine irregularities are formed on the outermost layer surface. For this reason, both toner transportability and durability were rejected.

  Moreover, the composition No. containing the roughness forming particles was used. In the developing roll according to Comparative Example 4 in which the outermost layer was formed by curing the ratio 4 only by heat treatment, image density unevenness occurred in the evaluation of durability. This is presumed that the toner component is deposited at the location where the roughness forming particles are present, the electric resistance becomes non-uniform, and the image quality is lowered.

  Moreover, the composition No. containing the roughness forming particles was used. In the developing roll according to Comparative Example 4 in which the outermost layer was formed by curing the ratio 4 only by heat treatment, image density unevenness occurred in the evaluation of durability. This is presumed that the roughness-forming particles deteriorated the toner and the photosensitive drum and thus caused a reduction in image quality.

  Further, the developing roll according to Comparative Example 5 in which the surface of the outermost layer is roughened only by the ultraviolet irradiation condition cannot obtain a result that satisfies both toner transportability and durability as compared with the developing roll according to the example. It was.

  In contrast, composition No. It was confirmed that the developing rolls according to Examples 12 to 15 in which 12 to 15 were cured with ultraviolet rays to form the outermost layer were excellent in both toner transportability and durability. This is because uniform and fine surface irregularities are formed on the surface of the outermost layer without adding roughness forming particles or polishing.

  While the embodiments and examples of the present invention have been described above, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above embodiment, the case where the conductive roll according to the present invention is applied to the charging roll and the developing roll is exemplified, but the conductive roll according to the present invention is also applicable to the toner supply roll, the transfer roll, and the like. Applicable.

Claims (5)

The outermost layer of the roll has an outermost layer,
The outermost layer comprises a cured product of an ultraviolet curable composition containing at least an ultraviolet polymerizable monomer and / or an ultraviolet polymerizable oligomer, an ultraviolet polymerization initiator, and an ultraviolet transmission reducing substance,
A conductive roll having fine irregularities on the surface of the outermost layer.   The conductive roll according to claim 1, wherein the outermost layer is subjected to at least one kind of crosslinking selected from isocyanate crosslinking, peroxide crosslinking, and electron beam irradiation crosslinking.   The conductive roll according to claim 1 or 2, wherein the ultraviolet curable composition further contains an organic polymer having no ultraviolet curable property. A first step of coating a UV-curable composition containing at least a UV-polymerizable monomer and / or UV-polymerizable oligomer, a UV-polymerization initiator, and a UV-transmission-reducing substance, and forming a coating layer;
A second step of curing the coating layer by irradiating the coating layer with ultraviolet rays and forming an outermost layer having fine irregularities on the surface;
The manufacturing method of the electroconductive roll characterized by having.   The method for producing a conductive roll according to claim 4, further comprising a third step of performing a crosslinking treatment on the outermost layer.