WO2019044137A1 - Charging member for electrophotographic apparatuses - Google Patents

Charging member for electrophotographic apparatuses Download PDF

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Publication number
WO2019044137A1
WO2019044137A1 PCT/JP2018/023772 JP2018023772W WO2019044137A1 WO 2019044137 A1 WO2019044137 A1 WO 2019044137A1 JP 2018023772 W JP2018023772 W JP 2018023772W WO 2019044137 A1 WO2019044137 A1 WO 2019044137A1
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Prior art keywords
acid
surface layer
range
charging member
conductive agent
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PCT/JP2018/023772
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French (fr)
Japanese (ja)
Inventor
健太 中里
井上　大輔
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住友理工株式会社
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Publication of WO2019044137A1 publication Critical patent/WO2019044137A1/en

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices

Definitions

  • the present invention relates to a charging member for an electrophotographic apparatus suitably used in an electrophotographic apparatus such as a copying machine, a printer, a facsimile, and the like adopting an electrophotographic method.
  • a document image is formed as an electrostatic latent image on a photosensitive drum charged by a charging member, and toner charged by a developing member is attached to the electrostatic latent image to form a toner image.
  • toner charged by a developing member is attached to the electrostatic latent image to form a toner image.
  • the charging member contacts the photosensitive drum with the non-transferred toner remaining on the surface of the photosensitive drum.
  • the conventional charging member is designed on the assumption that the non-transferred toner is scraped off by the cleaning blade, and is not designed in consideration of the adhesion of the non-transferred toner. Therefore, uncharged toner adheres to the charging member from the photosensitive drum at the time of charging of the photosensitive drum.
  • the untransferred toner attached to the charging member is a toner carrying a charge, and when the photosensitive drum is charged by the charging member to which the untransferred toner is attached, the charge of the untransferred toner causes the photosensitive drum to be overcharged. An image failure occurs.
  • Patent Document 1 discloses a charging member having a support, a conductive elastic layer formed on the support, and a surface layer formed on the conductive elastic layer, wherein the surface layer is at least (I) oxy Containing polysiloxane having alkylene group and (II) hetero atom-containing conductive polymer, that said polysiloxane has fluorinated alkyl group, that said conductive polymer is polyaniline compound or polythiophene compound, polythiophene It is stated to contain polystyrenesulphonic acid in relation.
  • patent document 1 when adding a conductive polymer to the surface layer in order to suppress the environmental fluctuation of electric resistance, patent document 1 suppresses the coating unevenness and the electrification deterioration, and the electric charge of the untransferred toner which was not scraped off It does not suppress the overcharge phenomenon of the photosensitive drum. Also, polyurethane is not used as a binder.
  • the problem to be solved by the present invention is to provide a charging member for an electrophotographic apparatus in which the overcharging phenomenon of the photosensitive drum due to the charge of untransferred toner is suppressed.
  • a charging member for an electrophotographic apparatus comprises an elastic layer and a surface layer formed on the outer periphery of the elastic layer, and the surface layer comprises the following (a) to (c) And the surface roughness Rz of the surface layer is in the range of 1.0 to 20 ⁇ m.
  • A urethane binder
  • conductive agent c
  • proton donating substance having an acid dissociation constant pKa in water at 25 ° C. in the range of -10 to 15
  • the component (c) is preferably a compound having an acid dissociation constant pKa in water at 25 ° C. in the range of ⁇ 5 to 10.
  • the component (c) is preferably a compound having an acid dissociation constant pKa in water at 25 ° C. in the range of ⁇ 10 to 5.
  • the (c) is preferably an organic acid.
  • the (c) is preferably a sulfonic acid.
  • the (b) is preferably carbon black.
  • the curing catalyst (a) is preferably a metal-based catalyst.
  • the surface hardness of the surface layer is preferably in the range of 0.1 to 10 N / mm 2 .
  • the surface layer is (a) a urethane binder, (b) a conductive agent, (c) an acid dissociation constant pKa in water at 25 ° C. in the range of ⁇ 10 to 15.
  • a proton donating substance and the surface roughness Rz of the surface layer being in the range of 1.0 to 20 ⁇ m, the charge amount is adjusted when the photosensitive member is charged by the charging member to which the untransferred toner adheres, The overcharge phenomenon of the photosensitive drum due to the charge of untransferred toner can be suppressed. This is presumably because the proton of (c) moves from the surface layer of the charging member to the non-transferred toner adhering to the surface layer of the charging member, and the influence of the charge of the non-transferred toner is suppressed.
  • the adjustment of the excellent charge amount while suppressing the urethanization reaction of (a) and the influence of the acid on the charging member It has a function.
  • the acid dissociation constant pKa in water at 25 ° C. in (c) is in the range of ⁇ 10 to 5
  • the charge amount is excellent while suppressing the urethanization reaction of (a) and the influence of the acid on the charging member.
  • the (c) is an organic acid, it has an excellent adjustment function of the charge amount while suppressing the urethanization reaction of (a) and the influence of the acid on the charging member.
  • (c) When (c) is a sulfonic acid, it has an excellent adjustment function of the charge amount while suppressing the influence of the urethanization reaction of (a) and the acid on the charging member.
  • the (b) When the (b) is carbon black, the function of adjusting the charge amount is excellent.
  • the curing catalyst (a) is a metal catalyst, the influence of the urethanation reaction (c) can be easily suppressed.
  • the surface hardness of the surface layer is in the range of 0.1 to 10 N / mm 2 , the function of suppressing the overcharge phenomenon is excellent while reducing the stress on the toner.
  • the shape of the charging member for an electrophotographic apparatus according to the present invention is not particularly limited as long as it charges a member to be charged such as a photosensitive drum.
  • a member to be charged such as a photosensitive drum.
  • the shape of a roll, plate, block or the like is applicable. Particularly preferred is a roll.
  • a roll-shaped thing (charging roll) is mentioned as an example, and is demonstrated.
  • FIG. 1 is a schematic view showing an appearance (a) of the charging roll for an electrophotographic apparatus according to an embodiment of the present invention, and a cross-sectional view along the line AA thereof (b).
  • the charging roll 10 includes a shaft 12, an elastic layer 14 formed on the outer periphery of the shaft 12, and a surface layer 16 formed on the outer periphery of the elastic layer 14.
  • the elastic layer 14 is a layer to be a base of the charging roll 10.
  • the surface layer 16 is a layer appearing on the surface of the charging roll 10.
  • the surface layer 16 contains the following (a) to (c).
  • the surface roughness Rz of the surface layer 16 is in the range of 1.0 to 20 ⁇ m.
  • the urethane binder is made of polyurethane.
  • the polyurethane comprises a cured product of a urethane composition.
  • the urethane composition contains at least a polyol, an isocyanate, and a curing catalyst.
  • the urethane composition may contain a crosslinking agent and a chain extender.
  • the said polyol is a polyol for urethane, and polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol etc. are mentioned.
  • One of these polyols may be used alone, or two or more thereof may be used in combination.
  • polyether polyols are more preferable from the viewpoint of suppressing hydrolysis and being excellent in heat stability.
  • the polyester polyol is obtained from a polybasic organic acid and a short chain polyol, and one having a hydroxyl group as an end group is preferably mentioned.
  • the polybasic organic acid is not particularly limited, and is a saturated fatty acid such as oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, isosebacic acid, maleic acid, Unsaturated fatty acids such as fumaric acid, dicarboxylic acids such as aromatic acids such as phthalic acid, isophthalic acid and terephthalic acid, acid anhydrides such as maleic anhydride and phthalic anhydride, dialkyl esters such as dimethyl terephthalate, and unsaturated fatty acids And dimer acids obtained by dimerization of
  • the short-chain polyol is not particularly limited, and examples thereof include diols such as ethylene glycol, diethylene glycol, triethylene glyco
  • polyester polyols include polyethylene adipate (PEA), polybutylene adipate (PBA), polyhexylen adipate (PHA), and a copolymer of ethylene adipate and butylene adipate (PEA / BA). It is mentioned as a thing. These may be used singly or in combination of two or more. Among these, polybutylene adipate (PBA) is particularly preferable in view of the improvement of the abrasion resistance, the improvement of the durability and the like.
  • Preferred examples of the polyether polyol include those obtained by ring opening polymerization or copolymerization of cyclic ethers.
  • examples of the cyclic ether include ethylene oxide, propylene oxide, trimethylene oxide, butylene oxide, ⁇ -methyltrimethylene oxide, 3,3‘-dimethyltrimethylene oxide, tetrahydrofuran, dioxane, dioxamine and the like.
  • Specific examples of polyether polyols include polyoxytetramethylene glycol, polyoxypropylene glycol and the like.
  • the number average molecular weight of the polyol is preferably 1,000 to 3,500. More preferably, it is in the range of 1500 to 2500. When the number average molecular weight is 1,000 or more, it is possible to suppress the decrease in physical properties of the obtained polyurethane. Moreover, the viscosity increase of a prepolymer can be suppressed and a moldability can be made favorable because a number average molecular weight is 3500 or less.
  • the above isocyanate is an isocyanate for urethane, and is 4,4'-diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), trimethylhexamethylene diisocyanate (TMHDI), Tolylene diisocyanate (TDI), carbodiimide-modified MDI, polymethylene phenyl isocyanate (PAPI), ortho toluidine diisocyanate (TODI), naphthyl diisocyanate (NDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), paraphenylene diisocyanate (PDI), lysine diisocyanate methyl ester (LDI), dimethyl diisocyanate (DD) ), And the like.
  • MDI 4,4'-diphenylmethane di
  • MDI 4,4′-diphenylmethane diisocyanate
  • an NCO-terminated urethane prepolymer obtained by reacting the above-mentioned isocyanate such as MDI with the above-mentioned polyol may be used.
  • the urethane prepolymer preferably has an NCO% in the range of 5 to 30% by mass in order to be NCO-terminated. NCO% is calculated by the following equation.
  • the curing catalyst is a catalyst that promotes the urethanization reaction.
  • amine compounds such as triethylenediamine (TEDA), tertiary amines, diazabicycloamines, salts of diazabicycloamine, quaternary ammonium salts, isocyanurate catalysts, organometallic compounds (metal catalysts) And the like. These may be used alone or in combination.
  • organic metal compounds metal-based catalysts
  • tertiary amines examples include trialkylamines such as triethylamine, tetraalkyldiamines such as N, N, N, N-tetramethyl-1,3-butanediamine, amino alcohols such as dimethylethanolamine, and bis (diethylethanolamine). And the like) ester amines such as adipate, morpholine derivatives, piperazine derivatives and the like can be mentioned.
  • diazabicycloamines examples include: 1,8-diazabicyclo (5.4.0) -undecene-7 (DBU), 1,5-diazabicyclo (4.3.0) -nonene-5 (DBN) it can.
  • Organic metal compounds include: dibutyltin dilaurate, dibutyltin di (2-ethylhexoate), organic tin compounds such as stannous 2-ethylcaproate and stannous oleate, potassium octylate, potassium acetate, carbonic acid
  • organic tin compounds such as stannous 2-ethylcaproate and stannous oleate, potassium octylate, potassium acetate, carbonic acid
  • Non-tin organic metal compounds such as bismuth acid and zirconium complexes can be mentioned.
  • the content of the curing catalyst is preferably in the range of 0.002 to 0.02 parts by mass, more preferably 0.005 to 0.015 parts by mass with respect to 100 parts by mass of the curing agent.
  • Crosslinking agents include triols.
  • triol trimethylolpropane (TMP), glycerin, 1,2,6-hexanetriol, trimethylolethane, 1,2,4-butanetriol, 1,2,3-pentanetriol, 2,3,4- Pentantriol, 1,3,4-pentanetriol, 1,2,5-pentanetriol, 1,2,4-pentanetriol, 2- (hydroxymethyl) -1,3-butanediol, 2- (hydroxymethyl) -1,4-butanediol, 3-methyl-1,2,3-butanetriol, 2-ethyl-1,2,3-propanetriol, 2-methyl-1,2,4-butanetriol and the like. .
  • TMP trimethylolpropane
  • glycerin 1,2,6-hexanetriol
  • trimethylolethane 1,2,4-butanetriol
  • 1,2,3-pentanetriol 1,2,3-pentanetriol
  • 1,4-butanediol 1,4-BD
  • ethylene glycol EG
  • 1,6-hexanediol 1,6-HD
  • diethylene glycol DEG
  • propylene glycol PG
  • dipropylene glycol DPG
  • 1,4-cyclohexanediol 1,4-cyclohexanedimethanol
  • xylene glycol triethylene glycol and the like.
  • 1,4-butanediol is particularly preferred.
  • Examples of the conductive agent include an electron conductive agent and an ion conductive agent.
  • the conductive agent may be only an electron conductive agent, or only an ion conductive agent, or an electron conductive agent and an ion conductive agent may be used in combination.
  • the electron conductive agent examples include carbon black, graphite, conductive titanium oxide, conductive zinc oxide, and conductive oxide such as conductive tin oxide. There is no particular limitation, but these may be used alone as an electron conductive agent, or may be used in combination of two or more. Among these, carbon black is preferred.
  • ion conductive agent examples include quaternary ammonium salts, quaternary phosphonium salts, borates, surfactants and the like. Although not particularly limited, these may be used alone as an ion conductive agent, or may be used in combination of two or more. Of these, quaternary ammonium salts are preferred.
  • the compounding amount of the (b) electron conductive agent as the conductive agent is preferably in the range of 40 to 140 parts by mass with respect to 100 parts by mass of the (a) urethane binder. More preferably, it is in the range of 80 to 120 parts by mass. Further, the compounding amount of the ion conductive agent as the (b) conductive agent is preferably in the range of 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the (a) urethane binder. More preferably, it is in the range of 0.5 to 3.0 parts by mass.
  • the average particle diameter of the electron conductive agent as the (b) conductive agent is not particularly limited, but is preferably 0.1 ⁇ m or more from the viewpoint of forming predetermined surface irregularities with the electron conductive agent. More preferably, it is 0.5 ⁇ m or more. On the other hand, from the viewpoint of dispersibility and the like, the average particle diameter of the electron conductive agent is preferably 1.0 ⁇ m or less. More preferably, it is 0.5 ⁇ m or less.
  • the average particle size of the electron conductive agent is represented by an arithmetic average diameter obtained by observing the electron conductive agent with an electron microscope.
  • (C) is a proton donating substance (protonic acid), which is capable of donating protons to the negatively charged non-transferred toner attached to the surface layer 16.
  • the pKa of the compound of (c) may be determined by an ordinary titration method as a method of examining experimentally, and it is also possible to examine known values from the literature such as Chemical Handbook (edited by The Chemical Society of Japan ⁇ Maruzen Co., Ltd.>) It is.
  • pKa is the first-stage dissociation constant pKa 1 .
  • the acid dissociation constant pKa in water at 25 ° C. of (c) is more preferably in the range of ⁇ 5 to 10, still more preferably in the range of ⁇ 5 to 5.
  • the urethanation reaction of (a) and the influence of the acid on the charge roll 10 can be easily suppressed. That is, it is difficult to inhibit the urethanation reaction of (a), and it is easy to suppress defects such as corrosion of the charging roll 10.
  • the pKa is 10 or less, the proton donating property is more excellent, and the effect of suppressing the influence of the charge of the untransferred toner is more excellent.
  • the proton donating property is particularly excellent, and the effect of suppressing the influence of the charge of the untransferred toner is particularly excellent.
  • Examples of (c) include organic acids and inorganic acids. Of these, organic acids are more preferred. The organic acid is easy to suppress the effect of the acid on the charging roll 10 and the urethanation reaction of (a) compared to the inorganic acid.
  • examples of inorganic acids include perchloric acid, sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid and boric acid.
  • examples of sulfonic acid, carboxylic acid and the like can be mentioned.
  • Examples of sulfonic acids include p-toluenesulfonic acid, p-phenolsulfonic acid, benzenesulfonic acid, methanesulfonic acid, 10-camphorsulfonic acid and the like.
  • carboxylic acid citric acid, tannic acid, benzoic acid, oxalic acid, formic acid, acetic acid and the like can be mentioned.
  • sulfonic acid is particularly preferable.
  • the blending amount of (c) is preferably in the range of 1.0 to 10 parts by mass with respect to 100 parts by mass of the (a) urethane binder. More preferably, it is in the range of 3.0 to 8.0 parts by mass. With respect to 100 parts by mass of the (a) urethane binder, protons can be delivered particularly efficiently when the amount of (c) is 1.0 parts by mass or more. Moreover, it is easy to suppress the influence of the acid with respect to the urethanation reaction of (a) and the charging roll 10 as the compounding quantity of (c) is 10 mass parts or less.
  • the surface layer 16 may contain (a) as a binder, and may or may not contain a binder made of another polymer.
  • the above (a) should just be a main component of the binder of surface layer 16, and the above (a) should be 50 mass% or more of the whole binder of surface 16 .
  • the surface layer 16 may contain an additive, if necessary, as long as the present invention is not inhibited.
  • additives lubricants, vulcanization accelerators, anti-aging agents, light stabilizers, viscosity modifiers, processing aids, flame retardants, plasticizers, foaming agents, fillers, dispersants, antifoam agents, pigments, release agents A mold agent etc. are mentioned.
  • the surface layer 16 can be formed by applying and drying a surface layer forming composition on the outer peripheral surface of the elastic layer 14.
  • the composition for forming a surface layer comprises the above urethane composition and the above (b) to (c).
  • grains for roughness formation are included as needed.
  • it optionally contains one or more of various additives added to the surface layer.
  • the solvent is included as needed.
  • the surface roughness of the surface layer 16 is set within the above range, and is about the same size as the particle diameter of the toner. As a result, the contact area with the untransferred toner adhering to the surface layer 16 is increased, and protons can be efficiently delivered.
  • the surface roughness Rz of the surface layer 16 is more than 20, the influence of the charge of the untransferred toner can not be sufficiently suppressed, and the image failure can not be suppressed.
  • the surface roughness Rz of the surface layer 16 is more preferably in the range of 1.0 to 15 ⁇ m, and still more preferably 3.0, from the viewpoint of increasing the contact area with the untransferred toner attached to the surface layer 16 or the like. Within the range of ⁇ 10 ⁇ m.
  • the surface roughness Rz of the surface layer 16 is a ten-point average roughness, and is measured in accordance with JIS B 0601 (1994).
  • the surface roughness of the surface layer 16 can be formed by various known methods. For example, (b) adjusting the particle diameter of the electron conductive agent as the conductive agent to adjust to a predetermined surface roughness, separately adding particles for forming a predetermined particle diameter to the surface layer 16, or There is a method of providing surface irregularities on the surface of the elastic layer 14 by a method such as transfer. Among these, a method of separately adding particles for roughness formation to the surface layer 16 is more preferable, from the viewpoint that an arbitrary roughness can be formed depending on the particle diameter, the blending amount, the liquid viscosity and the like.
  • the surface hardness of the surface layer 16 is preferably in the range of 0.1 to 10 N / mm 2 . More preferably, it is in the range of 1.0 to 8.0 N / mm 2 , more preferably in the range of 3.0 to 8.0 N / mm 2 .
  • the surface hardness of the surface layer 16 is 0.1 N / mm 2 or more, the overcharge phenomenon can be suppressed more effectively.
  • the surface hardness of the surface layer 16 is 10 N / mm 2 or less, stress on the toner can be easily reduced.
  • the surface hardness of the surface layer 16 can be expressed by Martens hardness.
  • the thickness of the surface layer 16 is not particularly limited, but is preferably in the range of 3.0 to 20 ⁇ m, more preferably in the range of 5.0 to 15 ⁇ m.
  • the thickness of the surface layer 16 is the thickness at the flat portion of the concave portion of the surface unevenness.
  • the volume resistivity of the surface layer 16 is not particularly limited, but is preferably 10 4 to 10 9 ⁇ ⁇ cm, more preferably 10 5 to 10 8 ⁇ ⁇ cm, still more preferably 10 6 to 10 7 ⁇ ⁇ It is in the range of cm.
  • the elastic layer 14 contains a base rubber (polymer component). Thereby, it becomes a layer which has rubber elasticity.
  • the elastic layer 14 is formed of a conductive rubber composition containing a base rubber.
  • the base rubber crosslinked rubber
  • the uncrosslinked rubber may be a polar rubber or a nonpolar rubber.
  • the polar rubber is a rubber having a polar group, and examples of the polar group include chloro group, nitrile group, carboxyl group and epoxy group.
  • Specific examples of polar rubbers include hydrin rubber, nitrile rubber (NBR), urethane rubber (U), acrylic rubber (copolymer of acrylic ester and 2-chloroethyl vinyl ether, ACM), chloroprene rubber (CR) And epoxidized natural rubber (ENR).
  • NBR nitrile rubber
  • U urethane rubber
  • acrylic rubber copolymer of acrylic ester and 2-chloroethyl vinyl ether, ACM
  • chloroprene rubber CR
  • EMR epoxidized natural rubber
  • a hydrin rubber and a nitrile rubber (NBR) are more preferable from the viewpoint that the volume resistivity tends to be particularly low.
  • hydrin rubbers examples 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. can be mentioned.
  • CO epichlorohydrin homopolymer
  • ECO epichlorohydrin-ethylene oxide binary copolymer
  • GCO epichlorohydrin-allyl glycidyl ether binary copolymer
  • GECO epichlorohydrin-ethylene oxide-allyl glycidyl ether ternary A copolymer
  • the polyether-type urethane rubber which has an ether bond in a molecule
  • numerator can be mentioned.
  • the polyether type urethane rubber can be produced by the reaction of a polyether having a hydroxyl group at both ends with a diisocyanate.
  • the polyether is not particularly limited, and polyethylene glycol, polypropylene glycol and the like can be mentioned. Although it does not specifically limit as diisocyanate, Tolylene diisocyanate, diphenylmethane diisocyanate etc. can be mentioned.
  • nonpolar rubbers examples include isoprene rubber (IR), natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR) and the like.
  • crosslinking agent a sulfur crosslinking agent, a peroxide crosslinking agent, and a dechlorination crosslinking agent can be mentioned. These crosslinking agents may be used alone or in combination of two or more.
  • sulfur crosslinking agents include conventionally known sulfur crosslinking agents such as powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur, sulfur chloride, thiuram vulcanization accelerator, and polymeric polysulfides. it can.
  • peroxide crosslinking agents include conventionally known peroxide crosslinking agents such as peroxy ketals, dialkyl peroxides, peroxy esters, ketone peroxides, peroxy dicarbonates, diacyl peroxides and hydroperoxides. Can.
  • a dithiocarbonate compound As a dechlorination crosslinking agent, a dithiocarbonate compound can be mentioned. More specifically, quinoxaline-2,3-dithiocarbonate, 6-methylquinoxaline-2,3-dithiocarbonate, 6-isopropylquinoxaline-2,3-dithiocarbonate, 5,8-dimethylquinoxaline-2,3- A dithio carbonate etc. can be mentioned.
  • the compounding amount of the crosslinking agent is preferably in the range of 0.1 to 2 parts by mass, more preferably 0.3 to 1.8 parts by mass with respect to 100 parts by mass of the non-crosslinked rubber from the viewpoint of hardly bleeding or the like. Within the range of part, more preferably within the range of 0.5 to 1.5 parts by mass.
  • a dechlorination crosslinking accelerator may be used in combination.
  • a dechlorination crosslinking accelerator 1,8-diazabicyclo (5,4,0) undecen-7 (hereinafter abbreviated as DBU) or a weak acid salt thereof can be mentioned.
  • DBU 1,8-diazabicyclo (5,4,0) undecen-7
  • the dechlorination crosslinking accelerator may be used in the form of DBU, it is preferably used in the form of its weak acid salt from the viewpoint of its handling.
  • the content of the dechlorination crosslinking accelerator is preferably in the range of 0.1 to 2 parts by mass with respect to 100 parts by mass of the uncrosslinked rubber, from the viewpoint of hardly bleeding. More preferably, it is in the range of 0.3 to 1.8 parts by mass, still more preferably in the range of 0.5 to 1.5 parts by mass.
  • the elastic layer 14 may contain a conductive agent such as an ion conductive agent or an electronic conductive agent.
  • a conductive agent such as an ion conductive agent or an electronic conductive agent.
  • the ion conductive agent and the electron conductive agent those mentioned in the surface layer 16 can be suitably used.
  • additives may be appropriately added to the elastic layer 14 as necessary.
  • additives lubricants, vulcanization accelerators, anti-aging agents, light stabilizers, viscosity modifiers, processing aids, flame retardants, plasticizers, foaming agents, fillers, dispersants, antifoam agents, pigments, release agents Examples include molds and the like.
  • the elastic layer 14 can be adjusted to a predetermined volume resistivity by the type of crosslinked rubber, the compounding amount of the ion conductive agent, the compounding of the electron conductive agent, and the like.
  • the volume resistivity of the elastic layer 14 may be appropriately set in the range of 10 2 to 10 10 ⁇ ⁇ cm, 10 3 to 10 9 ⁇ ⁇ cm, 10 4 to 10 8 ⁇ ⁇ cm, etc. depending on the application etc. .
  • the thickness of the elastic layer 14 is not particularly limited, and may be appropriately set in the range of 0.1 to 10 mm according to the application and the like.
  • the elastic layer 14 may be foam or non-foam.
  • the elastic layer 14 can be manufactured, for example, as follows. First, the shaft 12 is coaxially installed in the hollow portion of the roll forming mold, and the uncrosslinked conductive rubber composition is injected, heated and cured (crosslinked), and then removed or The elastic layer 14 is formed on the outer periphery of the shaft 12 by extruding an uncrosslinked conductive rubber composition on the surface of the shaft 12 or the like.
  • the shaft 12 is not particularly limited as long as it has conductivity. Specifically, a solid body made of metal such as iron, stainless steel, or aluminum, a cored bar made of a hollow body, and the like can be exemplified. An adhesive, a primer or the like may be applied to the surface of the shaft 12 as necessary. That is, the elastic layer 14 may be bonded to the shaft 12 via the adhesive layer (primer layer). The adhesive, the primer, etc. may be made conductive as required.
  • the surface layer 16 contains the above (a) to (c), and the surface roughness Rz of the surface layer 16 is in the range of 1.0 to 20 ⁇ m.
  • the charge amount is adjusted when the photosensitive drum is charged by the charging roll 10 to which the transfer toner adheres, and the overcharge phenomenon of the photosensitive drum due to the charge of the non-transfer toner can be suppressed. And the image defect by this is suppressed.
  • the above effect is obtained when the surface layer 16 contains a urethane binder. If the surface layer 16 does not contain a urethane binder but contains only another polymer binder, the above effect can not be obtained.
  • the configuration of the charging roll according to the present invention is not limited to the configuration shown in FIG.
  • another elastic layer may be provided between the shaft 12 and the elastic layer 14.
  • the other elastic layer is a layer to be a base of the charging roll, and the elastic layer 14 functions as a resistance adjusting layer or the like for adjusting the resistance of the charging roll.
  • the other elastic layer can be made of, for example, any of the materials mentioned as the material of the elastic layer 14.
  • another elastic layer may be provided between the elastic layer 14 and the surface layer 16.
  • the elastic layer 14 is a layer to be a base of the charging roll, and the other elastic layers function as a resistance adjusting layer or the like for adjusting the resistance of the charging roll.
  • Examples 1 to 7 ⁇ Preparation of Conductive Rubber Composition> Based on 100 parts by mass of isoprene rubber, 30 parts by mass of carbon black, 6 parts by mass of zinc oxide, 2 parts by mass of stearic acid, 1 part by mass of sulfur, 0.5 parts by mass of thiazole based vulcanization accelerator, 0 thiraum based vulcanization accelerator A conductive rubber composition was prepared by blending 5 parts by mass and 50 parts by mass of ground calcium carbonate, and kneading for 10 minutes using a closed-type mixer whose temperature was adjusted to 50 ° C.
  • -Rubber component Isoprene rubber (IR) [manufactured by JSR Corp., "JSR IR 2200”] ⁇ Conductive agent carbon black (electronic conductive agent) [Cabot Japan KK, “Show Black N762”] ⁇ Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., “Zinc oxide 2”) ⁇ Stearic acid (manufactured by NOF Corp., “Stearic Acid Sakura”) ⁇ Sulfur [made by Tsurumi Chemical Industries, Ltd., “powdered sulfur”] ⁇ Vulcanization accelerator Thiazole-based vulcanization accelerator [Ouchi Shinko Chemical Co., Ltd.
  • the prepared conductive rubber composition was extruded into a crown shape around the periphery of a core metal made of free-cutting steel (SUM) with a diameter of 6 mm.
  • the conductive rubber composition is supplied to the gap between the die and the cored bar while passing the cored bar to the circular opening of the die of the extrusion molding apparatus, whereby the outer periphery of the cored bar is made elastic.
  • the body layer was extruded.
  • the shape of the elastic layer precursor is made into a crown shape by changing the passing speed of the core metal and controlling the adhesion amount of the conductive rubber composition in the longitudinal direction of the core metal. It was then heat treated at 180 ° C. for 30 minutes. Thereby, a predetermined elastic layer (thickness 1.5 mm) was formed on the outer periphery of the cored bar.
  • a methyl ethyl ketone (MEK) 200 is blended with a urethane resin, a polyol, an isocyanate, a curing catalyst, a conductive agent, particles for roughness formation, and an additive having a predetermined pKa so that the blending amount (parts by mass) described in Table 1 is obtained.
  • the liquid composition for surface layer formation was prepared by adding a mass part and carrying out ultrasonic mixing and mixing and stirring for a predetermined time. Next, the liquid composition was roll-coated on the outer peripheral surface of the elastic layer and heat treated to form a surface layer (10 ⁇ m in thickness) on the outer periphery of the elastic layer. Thereby, a charging roll was produced.
  • the surface roughness Rz was adjusted by changing the type (particle diameter) of the roughness-forming particles.
  • Example 8 In the preparation of the surface layer, the surface hardness was adjusted by changing the thickness of the surface layer (liquid viscosity of the liquid composition for forming the surface layer).
  • a charging roll was produced in the same manner as in Examples 1 to 7 except for the above.
  • a charge roll was prepared in the same manner as Example 3, except that the binder ⁇ 2> (acrylic resin) or the binder ⁇ 3> (nylon resin) was used instead of the binder ⁇ 1> (urethane resin). .
  • the materials used as the surface layer material are as follows.
  • Isocyanate Toronso "Corronate HX”
  • Conductive agent ⁇ 1> Carbon black, manufactured by Lion "Ketjen EC300J”
  • Conductive agent ⁇ 2> Ion conductive agent, tetramethyl ammonium chloride (reagent)
  • Roughness-forming particles ⁇ 1> Acrylic particles, average particle size 1.0 ⁇ m, Sekisui Plastics Co., Ltd.
  • the surface hardness and the charge amount were measured for each of the produced charging rolls. Also, image evaluation was performed. The evaluation results and the composition of the surface layer forming composition are shown in the following table.
  • the photosensitive drum 1 of the “CLJ 4525 dn” cartridge made by HP is assembled to the rotating jig 6, and the charging rolls 2 are brought into contact thereon, and a load of 1 kg is loaded according to the both ends of the charging roll 2. did. At this time, the whole was surrounded by a box and shielded from light. Only a DC voltage of -1.0 KV was applied from the high voltage power supply 3 connected to the charging roll 2, and the drum potential after rotating the photosensitive drum 1 once was measured by the surface voltmeter 5 equipped with the high voltage probe 4. .
  • the surface layer of the charge roll contains (a) a urethane binder, (b) a conductive agent, and (c) a proton donating substance having an acid dissociation constant pKa in water at 25 ° C. in the range of -10 to 15. Also, it is found that when the surface roughness Rz of the surface layer is in the range of 1.0 to 20 ⁇ m, the difference between the charge amount when there is no toner fog and the charge amount when toner fog is small. The reason is presumed to be that the charge amount is adjusted at the time of charging of the photosensitive drum by the charging roll to which the non-transferred toner adheres from the above (c). As a result, the overcharging phenomenon of the photosensitive drum due to the charge of the non-transferred toner can be suppressed, so that the image failure can be suppressed.

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Abstract

Provided is a charging member for electrophotographic apparatuses that suppresses the over-charging of a photosensitive drum due to the charge of untransferred toner. According to the present invention, a charging member 10 for electrophotographic apparatuses is provided with an elastic layer 14 and a surface layer 16 that is formed on the outer circumference of the elastic layer 14. The surface layer 16 contains components (a)-(c) described below; and the surface roughness Rz of the surface layer 16 is within the range of 1.0-20 μm. (a) a binder that is composed of urethane (b) a conductive agent (c) a proton donor that has an acid dissociation constant pKa in water at 25°C within the range of from -10 to 15

Description

電子写真機器用帯電部材Charging member for electrophotographic apparatus
　本発明は、電子写真方式を採用する複写機、プリンター、ファクシミリなどの電子写真機器において好適に用いられる電子写真機器用帯電部材に関するものである。 The present invention relates to a charging member for an electrophotographic apparatus suitably used in an electrophotographic apparatus such as a copying machine, a printer, a facsimile, and the like adopting an electrophotographic method.
　電子写真機器による複写や印字は、帯電部材により帯電させた感光ドラムに原稿像を静電潜像として形成し、現像部材により帯電させたトナーを静電潜像に付着させてトナー像を形成し、トナー像を複写紙に転写することにより行われている。複写紙に転写されなかったトナーは、クリーニングブレードによって感光ドラムから掻き取られている。その後、再び帯電部材により感光ドラムが帯電される。帯電部材は、クリーニングブレードによる未転写トナーの掻き取りを前提とした設計となっている。 In copying and printing by an electrophotographic apparatus, a document image is formed as an electrostatic latent image on a photosensitive drum charged by a charging member, and toner charged by a developing member is attached to the electrostatic latent image to form a toner image. , By transferring the toner image to a copy sheet. The toner not transferred onto the copy paper is scraped off the photosensitive drum by the cleaning blade. Thereafter, the photosensitive drum is charged again by the charging member. The charging member is designed on the premise of scraping off the non-transferred toner by the cleaning blade.
特開２００９－１５１１６０号公報JP, 2009-151160, A
　電子写真機器の小型化の一環で、クリーニングブレードを用いない構成が検討されている。クリーニングブレードを用いないと、未転写トナーが感光ドラムの表面に残った状態で帯電部材が感光ドラムに接触する。従来の帯電部材は、クリーニングブレードによる未転写トナーの掻き取りを前提とした設計であり、未転写トナーの付着を考慮した設計になっていない。このため、感光ドラムの帯電時に、感光ドラムから帯電部材に未転写トナーが付着する。帯電部材に付着した未転写トナーは電荷を帯びているトナーであり、未転写トナーが付着した帯電部材によって感光ドラムを帯電させると、未転写トナーの電荷によって感光ドラムの過帯電現象が発生し、画像不具合が生じる。 As part of the miniaturization of electrophotographic devices, a configuration not using a cleaning blade is being studied. If the cleaning blade is not used, the charging member contacts the photosensitive drum with the non-transferred toner remaining on the surface of the photosensitive drum. The conventional charging member is designed on the assumption that the non-transferred toner is scraped off by the cleaning blade, and is not designed in consideration of the adhesion of the non-transferred toner. Therefore, uncharged toner adheres to the charging member from the photosensitive drum at the time of charging of the photosensitive drum. The untransferred toner attached to the charging member is a toner carrying a charge, and when the photosensitive drum is charged by the charging member to which the untransferred toner is attached, the charge of the untransferred toner causes the photosensitive drum to be overcharged. An image failure occurs.
　特許文献１には、支持体、該支持体上の形成された導電性弾性層、該導電性弾性層上に形成された表面層を有する帯電部材において、該表面層が、少なくとも（Ｉ）オキシアルキレン基を有するポリシロキサンおよび（ＩＩ）ヘテロ原子含有導電性ポリマーを含有すること、前記ポリシロキサンがフッ化アルキル基を有すること、前記導電性ポリマーがポリアニリン化合物またはポリチオフェン化合物であること、ポリチオフェンとの関係においてポリスチレンスルホン酸を含有することが記載されている。しかし、特許文献１は、電気抵抗の環境変動を抑えるために表面層に導電性ポリマーを添加するに際して、塗工ムラや通電劣化を抑えるものであり、掻き取られなかった未転写トナーの電荷によって感光ドラムの過帯電現象を抑えるものではない。また、バインダーとしてポリウレタンを用いるものではない。 Patent Document 1 discloses a charging member having a support, a conductive elastic layer formed on the support, and a surface layer formed on the conductive elastic layer, wherein the surface layer is at least (I) oxy Containing polysiloxane having alkylene group and (II) hetero atom-containing conductive polymer, that said polysiloxane has fluorinated alkyl group, that said conductive polymer is polyaniline compound or polythiophene compound, polythiophene It is stated to contain polystyrenesulphonic acid in relation. However, when adding a conductive polymer to the surface layer in order to suppress the environmental fluctuation of electric resistance, patent document 1 suppresses the coating unevenness and the electrification deterioration, and the electric charge of the untransferred toner which was not scraped off It does not suppress the overcharge phenomenon of the photosensitive drum. Also, polyurethane is not used as a binder.
　本発明が解決しようとする課題は、未転写トナーの電荷による感光ドラムの過帯電現象が抑えられた電子写真機器用帯電部材を提供することにある。 The problem to be solved by the present invention is to provide a charging member for an electrophotographic apparatus in which the overcharging phenomenon of the photosensitive drum due to the charge of untransferred toner is suppressed.
　上記課題を解決するため本発明に係る電子写真機器用帯電部材は、弾性体層と、前記弾性体層の外周に形成された表層と、を備え、前記表層が下記（ａ）～（ｃ）を含有し、かつ、前記表層の表面粗さＲｚが１．０～２０μｍの範囲内であることを要旨とするものである。
（ａ）ウレタン製バインダー
（ｂ）導電剤
（ｃ）２５℃における水中の酸解離定数ｐＫａが－１０～１５の範囲内のプロトン供与性物質 In order to solve the above problems, a charging member for an electrophotographic apparatus according to the present invention comprises an elastic layer and a surface layer formed on the outer periphery of the elastic layer, and the surface layer comprises the following (a) to (c) And the surface roughness Rz of the surface layer is in the range of 1.0 to 20 μm.
(A) urethane binder (b) conductive agent (c) proton donating substance having an acid dissociation constant pKa in water at 25 ° C. in the range of -10 to 15
　前記（ｃ）は、２５℃における水中の酸解離定数ｐＫａが－５～１０の範囲内の化合物であることが好ましい。前記（ｃ）は、２５℃における水中の酸解離定数ｐＫａが－１０～５の範囲内の化合物であることが好ましい。前記（ｃ）は、有機酸であることが好ましい。前記（ｃ）は、スルホン酸であることが好ましい。前記（ｂ）は、カーボンブラックであることが好ましい。前記（ａ）の硬化触媒は、金属系触媒であることが好ましい。前記表層の表面硬度は、０．１～１０Ｎ／ｍｍ２の範囲内であることが好ましい。 The component (c) is preferably a compound having an acid dissociation constant pKa in water at 25 ° C. in the range of −5 to 10. The component (c) is preferably a compound having an acid dissociation constant pKa in water at 25 ° C. in the range of −10 to 5. The (c) is preferably an organic acid. The (c) is preferably a sulfonic acid. The (b) is preferably carbon black. The curing catalyst (a) is preferably a metal-based catalyst. The surface hardness of the surface layer is preferably in the range of 0.1 to 10 N / mm 2 .
　本発明に係る電子写真機器用帯電部材によれば、表層が（ａ）ウレタン製バインダー、（ｂ）導電剤、（ｃ）２５℃における水中の酸解離定数ｐＫａが－１０～１５の範囲内のプロトン供与性物質を含有し、かつ、表層の表面粗さＲｚが１．０～２０μｍの範囲内であることで、未転写トナーが付着する帯電部材による感光ドラムの帯電時に帯電量を調整し、未転写トナーの電荷による感光ドラムの過帯電現象が抑えられる。これは、（ｃ）のプロトンが帯電部材の表層から帯電部材の表層に付着する未転写トナーに移動し、未転写トナーの電荷の影響が抑えられるためと推察される。 According to the charging member for an electrophotographic apparatus according to the present invention, the surface layer is (a) a urethane binder, (b) a conductive agent, (c) an acid dissociation constant pKa in water at 25 ° C. in the range of −10 to 15. By containing a proton donating substance and the surface roughness Rz of the surface layer being in the range of 1.0 to 20 μm, the charge amount is adjusted when the photosensitive member is charged by the charging member to which the untransferred toner adheres, The overcharge phenomenon of the photosensitive drum due to the charge of untransferred toner can be suppressed. This is presumably because the proton of (c) moves from the surface layer of the charging member to the non-transferred toner adhering to the surface layer of the charging member, and the influence of the charge of the non-transferred toner is suppressed.
　前記（ｃ）の２５℃における水中の酸解離定数ｐＫａが－５～１０の範囲内であると、（ａ）のウレタン化反応や帯電部材に対する酸の影響を抑えつつ、優れた帯電量の調整機能を有する。また、前記（ｃ）の２５℃における水中の酸解離定数ｐＫａが－１０～５の範囲内であると、（ａ）のウレタン化反応や帯電部材に対する酸の影響を抑えつつ、優れた帯電量の調整機能を有する。前記（ｃ）が有機酸であると、（ａ）のウレタン化反応や帯電部材に対する酸の影響を抑えつつ、優れた帯電量の調整機能を有する。前記（ｃ）が、スルホン酸であると、特に、（ａ）のウレタン化反応や帯電部材に対する酸の影響を抑えつつ、優れた帯電量の調整機能を有する。前記（ｂ）がカーボンブラックであると、帯電量の調整機能により優れる。前記（ａ）の硬化触媒が金属系触媒であると、（ｃ）によるウレタン化反応の影響が抑えられやすい。前記表層の表面硬度が０．１～１０Ｎ／ｍｍ２の範囲内であると、トナーへのストレスを低減しつつ、過帯電現象の抑制機能により優れる。 When the acid dissociation constant pKa in water at 25 ° C. in (c) is in the range of −5 to 10, the adjustment of the excellent charge amount while suppressing the urethanization reaction of (a) and the influence of the acid on the charging member It has a function. When the acid dissociation constant pKa in water at 25 ° C. in (c) is in the range of −10 to 5, the charge amount is excellent while suppressing the urethanization reaction of (a) and the influence of the acid on the charging member. Have adjustment function. When the (c) is an organic acid, it has an excellent adjustment function of the charge amount while suppressing the urethanization reaction of (a) and the influence of the acid on the charging member. When (c) is a sulfonic acid, it has an excellent adjustment function of the charge amount while suppressing the influence of the urethanization reaction of (a) and the acid on the charging member. When the (b) is carbon black, the function of adjusting the charge amount is excellent. When the curing catalyst (a) is a metal catalyst, the influence of the urethanation reaction (c) can be easily suppressed. When the surface hardness of the surface layer is in the range of 0.1 to 10 N / mm 2 , the function of suppressing the overcharge phenomenon is excellent while reducing the stress on the toner.
本発明の一実施形態に係る電子写真機器用帯電ロールの外観模式図（ａ）と、そのＡ－Ａ線断面図（ｂ）である。BRIEF DESCRIPTION OF THE DRAWINGS They are an external appearance schematic diagram (a) of the charging roll for electrophotographic apparatuses which concerns on one Embodiment of this invention, and its AA sectional drawing (b). 感光ドラムの帯電量の測定方法を表す図である。It is a figure showing the measuring method of the electrification amount of a photosensitive drum.
　以下、本発明について詳細に説明する。本発明に係る電子写真機器用帯電部材は、感光ドラムなどの被帯電体を帯電させるものであれば、特に形状が限定されるものではない。例えば、ロール状、プレート状、ブロック状などの形状のものが適用可能である。特に好ましいものとしては、ロール状のものである。以下、ロール状のもの（帯電ロール）を例に挙げて説明する。 Hereinafter, the present invention will be described in detail. The shape of the charging member for an electrophotographic apparatus according to the present invention is not particularly limited as long as it charges a member to be charged such as a photosensitive drum. For example, the shape of a roll, plate, block or the like is applicable. Particularly preferred is a roll. Hereinafter, a roll-shaped thing (charging roll) is mentioned as an example, and is demonstrated.
　本発明に係る電子写真機器用帯電ロール（以下、単に帯電ロールということがある。）について詳細に説明する。図１は、本発明の一実施形態に係る電子写真機器用帯電ロールの外観模式図（ａ）と、そのＡ－Ａ線断面図（ｂ）である。 The charging roll for an electrophotographic apparatus (hereinafter, may be simply referred to as charging roll) according to the present invention will be described in detail. FIG. 1 is a schematic view showing an appearance (a) of the charging roll for an electrophotographic apparatus according to an embodiment of the present invention, and a cross-sectional view along the line AA thereof (b).
　帯電ロール１０は、軸体１２と、軸体１２の外周に形成された弾性体層１４と、弾性体層１４の外周に形成された表層１６と、を備える。弾性体層１４は、帯電ロール１０のベースとなる層である。表層１６は、帯電ロール１０の表面に現れる層となっている。 The charging roll 10 includes a shaft 12, an elastic layer 14 formed on the outer periphery of the shaft 12, and a surface layer 16 formed on the outer periphery of the elastic layer 14. The elastic layer 14 is a layer to be a base of the charging roll 10. The surface layer 16 is a layer appearing on the surface of the charging roll 10.
表層１６は、下記（ａ）～（ｃ）を含有する。また、表層１６の表面粗さＲｚは１．０～２０μｍの範囲内である。
（ａ）ウレタン製バインダー
（ｂ）導電剤
（ｃ）２５℃における水中の酸解離定数ｐＫａが－１０～１５の範囲内のプロトン供与性物質 The surface layer 16 contains the following (a) to (c). The surface roughness Rz of the surface layer 16 is in the range of 1.0 to 20 μm.
(A) urethane binder (b) conductive agent (c) proton donating substance having an acid dissociation constant pKa in water at 25 ° C. in the range of -10 to 15
　（ａ）ウレタン製バインダーは、ポリウレタンからなる。ポリウレタンは、ウレタン組成物の硬化物からなる。ウレタン組成物は、ポリオール、イソシアネート、硬化触媒を少なくとも含有する。ウレタン組成物は、架橋剤や鎖延長剤を含有してもよい。 (A) The urethane binder is made of polyurethane. The polyurethane comprises a cured product of a urethane composition. The urethane composition contains at least a polyol, an isocyanate, and a curing catalyst. The urethane composition may contain a crosslinking agent and a chain extender.
　上記ポリオールは、ウレタン用のポリオールであり、ポリエステルポリオール、ポリエーテルポリオール、ポリカプロラクトンポリオール、ポリカーボネートポリオールなどが挙げられる。これらは上記ポリオールとして１種単独で用いてもよいし、２種以上を併用してもよい。これらのうちでは、加水分解が抑えられ、熱安定性に優れるなどの観点から、ポリエーテルポリオールがより好ましい。 The said polyol is a polyol for urethane, and polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol etc. are mentioned. One of these polyols may be used alone, or two or more thereof may be used in combination. Among these, polyether polyols are more preferable from the viewpoint of suppressing hydrolysis and being excellent in heat stability.
　ポリエステルポリオールは、多塩基性有機酸と短鎖ポリオールとから得られ、水酸基を末端基とするものが好適に挙げられる。多塩基性有機酸は、特に限定されるものではないが、シュウ酸，コハク酸，グルタル酸，アジピン酸，ピメリン酸，スベリン酸，アゼライン酸，セバシン酸，イソセバシン酸等の飽和脂肪酸、マレイン酸，フマル酸等の不飽和脂肪酸、フタル酸，イソフタル酸，テレフタル酸等の芳香族酸等のジカルボン酸、無水マレイン酸，無水フタル酸等の酸無水物、テレフタル酸ジメチル等のジアルキルエステル、不飽和脂肪酸の二量化によって得られるダイマー酸等が挙げられる。短鎖ポリオールとしては、特に限定するものではなく、例えば、エチレングリコール，ジエチレングリコール，トリエチレングリコール，プロピレングリコール，ジプロピレングリコール，ブチレングリコール，ネオペンチルグリコール，１，６－ヘキシレングリコール等のジオール、トリメチロールエタン，トリメチロールプロパン，ヘキサントリオール，グリセリン等のトリオール、ソルビトール等のヘキサオール等が挙げられる。 The polyester polyol is obtained from a polybasic organic acid and a short chain polyol, and one having a hydroxyl group as an end group is preferably mentioned. The polybasic organic acid is not particularly limited, and is a saturated fatty acid such as oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, isosebacic acid, maleic acid, Unsaturated fatty acids such as fumaric acid, dicarboxylic acids such as aromatic acids such as phthalic acid, isophthalic acid and terephthalic acid, acid anhydrides such as maleic anhydride and phthalic anhydride, dialkyl esters such as dimethyl terephthalate, and unsaturated fatty acids And dimer acids obtained by dimerization of The short-chain polyol is not particularly limited, and examples thereof include diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, 1,6-hexylene glycol, and the like. Examples include methylol ethane, trimethylol propane, hexane triol, triols such as glycerin, and hexaols such as sorbitol.
　ポリエステルポリオールとしては、具体的には、ポリエチレンアジペート（ＰＥＡ）、ポリブチレンアジペート（ＰＢＡ）、ポリヘキシレンアジペート（ＰＨＡ）、エチレンアジペートとブチレンアジペートとの共重合体（ＰＥＡ／ＢＡ）などがより好適なものとして挙げられる。これらは、１種単独で用いられてもよいし、２種以上を併用してもよい。これらのうちでは、耐摩耗性の向上、耐久性の向上などの観点から、ポリブチレンアジペート（ＰＢＡ）が特に好ましい。 Specific examples of polyester polyols include polyethylene adipate (PEA), polybutylene adipate (PBA), polyhexylen adipate (PHA), and a copolymer of ethylene adipate and butylene adipate (PEA / BA). It is mentioned as a thing. These may be used singly or in combination of two or more. Among these, polybutylene adipate (PBA) is particularly preferable in view of the improvement of the abrasion resistance, the improvement of the durability and the like.
　ポリエーテルポリオールは、環状エーテルの開環重合または共重合などによって得られるものが好適に挙げられる。環状エーテルとしては、例えば、エチレンオキサイド、プロピレンオキサイド、トリメチレンオキサイド、ブチレンオキサイド、α－メチルトリメチレンオキサイド、３，３‘－ジメチルトリメチレンオキサイド、テトラヒドロフラン、ジオキサン、ジオキサミン等が挙げられる。ポリエーテルポリオールは、具体的には、ポリオキシテトラメチレングリコール、ポリオキシプロピレングリコールなどが挙げられる。 Preferred examples of the polyether polyol include those obtained by ring opening polymerization or copolymerization of cyclic ethers. Examples of the cyclic ether include ethylene oxide, propylene oxide, trimethylene oxide, butylene oxide, α-methyltrimethylene oxide, 3,3‘-dimethyltrimethylene oxide, tetrahydrofuran, dioxane, dioxamine and the like. Specific examples of polyether polyols include polyoxytetramethylene glycol, polyoxypropylene glycol and the like.
　ポリオールの数平均分子量は、１０００～３５００のものが好ましい。より好ましくは１５００～２５００の範囲内である。数平均分子量が１０００以上であることで、得られるポリウレタンの物性低下を抑えることができる。また、数平均分子量が３５００以下であることで、プレポリマーの粘度上昇を抑え、成形性を良好にすることができる。 The number average molecular weight of the polyol is preferably 1,000 to 3,500. More preferably, it is in the range of 1500 to 2500. When the number average molecular weight is 1,000 or more, it is possible to suppress the decrease in physical properties of the obtained polyurethane. Moreover, the viscosity increase of a prepolymer can be suppressed and a moldability can be made favorable because a number average molecular weight is 3500 or less.
　上記イソシアネートは、ウレタン用のイソシアネートであり、４，４’－ジフェニルメタンジイソシアネート（ＭＤＩ）、イソホロンジイソシアネート（ＩＰＤＩ）、４，４’－ジシクロヘキシルメタンジイソシアネート（水添ＭＤＩ）、トリメチルヘキサメチレンジイソシアネート（ＴＭＨＤＩ）、トリレンジイソシアネート（ＴＤＩ）、カルボジイミド変性ＭＤＩ、ポリメチレンフェニルイソシアネート（ＰＡＰＩ）、オルトトルイジンジイソシアネート（ＴＯＤＩ）、ナフチレンジイソシアネート（ＮＤＩ）、キシレンジイソシアネート（ＸＤＩ）、ヘキサメチレンジイソシアネート（ＨＭＤＩ）、パラフェニレンジイソシアネート（ＰＤＩ）、リジンジイソシアネートメチルエステル（ＬＤＩ）、ジメチルジイソシアネート（ＤＤＩ）などが挙げられる。これらは、１種単独で用いられてもよいし、２種以上を併用してもよい。これらのうちでは、耐摩耗性の向上、取扱いやすさ、入手容易、コストなどの観点から、４，４’－ジフェニルメタンジイソシアネート（ＭＤＩ）が特に好ましい。 The above isocyanate is an isocyanate for urethane, and is 4,4'-diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), trimethylhexamethylene diisocyanate (TMHDI), Tolylene diisocyanate (TDI), carbodiimide-modified MDI, polymethylene phenyl isocyanate (PAPI), ortho toluidine diisocyanate (TODI), naphthyl diisocyanate (NDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), paraphenylene diisocyanate ( PDI), lysine diisocyanate methyl ester (LDI), dimethyl diisocyanate (DD) ), And the like. These may be used singly or in combination of two or more. Among these, 4,4′-diphenylmethane diisocyanate (MDI) is particularly preferable in terms of improvement in abrasion resistance, ease of handling, availability, cost and the like.
　上記イソシアネートは、上記するＭＤＩなどのイソシアネートと上記ポリオールとを反応させて得られるＮＣＯ末端のウレタンプレポリマーを用いてもよい。ウレタンプレポリマーは、ＮＣＯ末端とするため、ＮＣＯ％が５～３０質量％の範囲内であることが好ましい。ＮＣＯ％は、下記の式で算出される。
Figure JPOXMLDOC01-appb-M000001
 As the above-mentioned isocyanate, an NCO-terminated urethane prepolymer obtained by reacting the above-mentioned isocyanate such as MDI with the above-mentioned polyol may be used. The urethane prepolymer preferably has an NCO% in the range of 5 to 30% by mass in order to be NCO-terminated. NCO% is calculated by the following equation.
Figure JPOXMLDOC01-appb-M000001
　硬化触媒は、ウレタン化反応を促進する触媒である。硬化触媒としては、トリエチレンジアミン（ＴＥＤＡ）、第三級アミン、ジアザビシクロアミン、ジアザビシクロアミンの塩などのアミン化合物や四級アンモニウム塩、イソシアヌレート化触媒、有機金属化合物（金属系触媒）などを挙げることができる。これらは単独で用いても良いし、組み合わせて用いて良い。これらのうちでは、（ｃ）によるウレタン化反応の影響が抑えられやすいなどの観点から、有機金属化合物（金属系触媒）が好ましい。 The curing catalyst is a catalyst that promotes the urethanization reaction. As a curing catalyst, amine compounds such as triethylenediamine (TEDA), tertiary amines, diazabicycloamines, salts of diazabicycloamine, quaternary ammonium salts, isocyanurate catalysts, organometallic compounds (metal catalysts) And the like. These may be used alone or in combination. Among these, organic metal compounds (metal-based catalysts) are preferable from the viewpoint that the influence of the urethanation reaction by (c) can be easily suppressed.
　第三級アミンとしては、トリエチルアミンなどのトリアルキルアミン、Ｎ，Ｎ，Ｎ，Ｎ－テトラメチル－１，３－ブタンジアミンなどのテトラアルキルジアミン、ジメチルエタノールアミンなどのアミノアルコール、ビス（ジエチルエタノールアミン）アジペートなどのエステルアミン、モルホリン誘導体、ピペラジン誘導体などを挙げることができる。 Examples of tertiary amines include trialkylamines such as triethylamine, tetraalkyldiamines such as N, N, N, N-tetramethyl-1,3-butanediamine, amino alcohols such as dimethylethanolamine, and bis (diethylethanolamine). And the like) ester amines such as adipate, morpholine derivatives, piperazine derivatives and the like can be mentioned.
　ジアザビシクロアミンとしては、１，８－ジアザビシクロ（５．４．０）－ウンデセン－７（ＤＢＵ）、１，５－ジアザビシクロ（４．３．０）－ノネン－５（ＤＢＮ）を挙げることができる。 Examples of diazabicycloamines include: 1,8-diazabicyclo (5.4.0) -undecene-7 (DBU), 1,5-diazabicyclo (4.3.0) -nonene-5 (DBN) it can.
　有機金属化合物としては、ジブチル錫ジラウレート、ジブチル錫ジ（２－エチルヘキソエート）、２－エチルカプロン酸第１錫、オレイン酸第１錫などの有機錫化合物、オクチル酸カリウム、酢酸カリウム、カルボン酸ビスマス、ジルコニウム錯体などの非スズ系有機金属化合物などを挙げることができる。 Organic metal compounds include: dibutyltin dilaurate, dibutyltin di (2-ethylhexoate), organic tin compounds such as stannous 2-ethylcaproate and stannous oleate, potassium octylate, potassium acetate, carbonic acid Non-tin organic metal compounds such as bismuth acid and zirconium complexes can be mentioned.
　硬化触媒の含有量は、硬化剤１００質量部に対し、好ましくは０．００２～０．０２質量部、より好ましくは０．００５～０．０１５質量部の範囲内である。 The content of the curing catalyst is preferably in the range of 0.002 to 0.02 parts by mass, more preferably 0.005 to 0.015 parts by mass with respect to 100 parts by mass of the curing agent.
　架橋剤としては、トリオールが挙げられる。トリオールとしては、トリメチロールプロパン（ＴＭＰ）、グリセリン、１，２，６－ヘキサントリオール、トリメチロールエタン、１，２，４－ブタントリオール、１，２，３－ペンタントリオール、２，３，４－ペンタントリオール、１，３，４－ペンタントリオール、１，２，５－ペンタントリオール、１，２，４－ペンタントリオール、２－（ヒドロキシメチル）－１，３－ブタンジオール、２－（ヒドロキシメチル）－１，４－ブタンジオール、３－メチル－１，２，３－ブタントリオール、２－エチル－１，２，３－プロパントリオール、２―メチル－１，２，４－ブタントリオールなどが挙げられる。これらは、１種単独で用いてもよいし、２種以上を併用してもよい。これらのうちでは、トリメチロールプロパンが特に好ましい。 Crosslinking agents include triols. As triol, trimethylolpropane (TMP), glycerin, 1,2,6-hexanetriol, trimethylolethane, 1,2,4-butanetriol, 1,2,3-pentanetriol, 2,3,4- Pentantriol, 1,3,4-pentanetriol, 1,2,5-pentanetriol, 1,2,4-pentanetriol, 2- (hydroxymethyl) -1,3-butanediol, 2- (hydroxymethyl) -1,4-butanediol, 3-methyl-1,2,3-butanetriol, 2-ethyl-1,2,3-propanetriol, 2-methyl-1,2,4-butanetriol and the like. . These may be used alone or in combination of two or more. Of these, trimethylolpropane is particularly preferred.
　鎖延長剤としては、１，４－ブタンジオール（１，４－ＢＤ）、エチレングリコール（ＥＧ）、１，６－ヘキサンジオール（１，６－ＨＤ）、ジエチレングリコール（ＤＥＧ）、プロピレングリコール（ＰＧ）、ジプロピレングリコール（ＤＰＧ）、１，４－シクロヘキサンジオール、１，４－シクロヘキサンジメタノール、キシレングリコール、トリエチレングリコールなどが挙げられる。これらは、１種単独で用いてもよいし、２種以上を併用してもよい。これらのうちでは、１，４－ブタンジオールが特に好ましい。 As chain extenders, 1,4-butanediol (1,4-BD), ethylene glycol (EG), 1,6-hexanediol (1,6-HD), diethylene glycol (DEG), propylene glycol (PG) And dipropylene glycol (DPG), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, xylene glycol, triethylene glycol and the like. These may be used alone or in combination of two or more. Among these, 1,4-butanediol is particularly preferred.
　（ｂ）導電剤としては、電子導電剤、イオン導電剤が挙げられる。（ｂ）導電剤は、電子導電剤のみであってもよいし、イオン導電剤のみであってもよいし、電子導電剤とイオン導電剤を併用してもよい。 (B) Examples of the conductive agent include an electron conductive agent and an ion conductive agent. (B) The conductive agent may be only an electron conductive agent, or only an ion conductive agent, or an electron conductive agent and an ion conductive agent may be used in combination.
　電子導電剤としては、カーボンブラック、グラファイト、導電性酸化チタン，導電性酸化亜鉛，導電性酸化スズなどの導電性酸化物などが挙げられる。特に限定されるものではないが、これらは、電子導電剤として１種単独で用いてもよいし、２種以上組み合わせて用いてもよい。これらのうちでは、カーボンブラックが好ましい。 Examples of the electron conductive agent include carbon black, graphite, conductive titanium oxide, conductive zinc oxide, and conductive oxide such as conductive tin oxide. There is no particular limitation, but these may be used alone as an electron conductive agent, or may be used in combination of two or more. Among these, carbon black is preferred.
　イオン導電剤としては、第四級アンモニウム塩、第四級ホスホニウム塩、ホウ酸塩、界面活性剤などが挙げられる。特に限定されるものではないが、これらは、イオン導電剤として１種単独で用いてもよいし、２種以上組み合わせて用いてもよい。これらのうちでは、第四級アンモニウム塩が好ましい。 Examples of the ion conductive agent include quaternary ammonium salts, quaternary phosphonium salts, borates, surfactants and the like. Although not particularly limited, these may be used alone as an ion conductive agent, or may be used in combination of two or more. Of these, quaternary ammonium salts are preferred.
　（ｂ）導電剤としての電子導電剤の配合量は、（ａ）ウレタン製バインダー１００質量部に対し、４０～１４０質量部の範囲内であることが好ましい。より好ましくは８０～１２０質量部の範囲内である。また、（ｂ）導電剤としてのイオン導電剤の配合量は、（ａ）ウレタン製バインダー１００質量部に対し、０．１～５．０質量部の範囲内であることが好ましい。より好ましくは０．５～３．０質量部の範囲内である。 The compounding amount of the (b) electron conductive agent as the conductive agent is preferably in the range of 40 to 140 parts by mass with respect to 100 parts by mass of the (a) urethane binder. More preferably, it is in the range of 80 to 120 parts by mass. Further, the compounding amount of the ion conductive agent as the (b) conductive agent is preferably in the range of 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the (a) urethane binder. More preferably, it is in the range of 0.5 to 3.0 parts by mass.
　（ｂ）導電剤としての電子導電剤の平均粒径は、特に限定されるものではないが、電子導電剤によって所定の表面凹凸を形成するなどの観点から、０．１μｍ以上が好ましい。より好ましくは０．５μｍ以上である。一方、分散性などの観点から、電子導電剤の平均粒径は、１．０μｍ以下が好ましい。より好ましくは０．５μｍ以下である。電子導電剤の平均粒径は、電子導電剤を電子顕微鏡で観察して求めた算術平均径で表される。 The average particle diameter of the electron conductive agent as the (b) conductive agent is not particularly limited, but is preferably 0.1 μm or more from the viewpoint of forming predetermined surface irregularities with the electron conductive agent. More preferably, it is 0.5 μm or more. On the other hand, from the viewpoint of dispersibility and the like, the average particle diameter of the electron conductive agent is preferably 1.0 μm or less. More preferably, it is 0.5 μm or less. The average particle size of the electron conductive agent is represented by an arithmetic average diameter obtained by observing the electron conductive agent with an electron microscope.
　（ｃ）は、プロトン供与性物質（プロトン酸）であり、表層１６に付着する、マイナスに帯電している未転写トナーに対しプロトンを供与することができるものである。これにより、未転写トナーの電荷の影響が抑えられ、感光ドラムなどの被帯電体の過帯電が抑えられ、画像不具合が抑えられる。（ｃ）の化合物のｐＫａは、実験的に調べる方法としては通常の滴定法が挙げられ、化学便覧（日本化学会編＜丸善株式会社＞）等の文献から文献既知の値を調べることも可能である。なお、（ｃ）の化合物が多価の酸である場合、ｐＫａは一段目の解離定数ｐＫａ１である。 (C) is a proton donating substance (protonic acid), which is capable of donating protons to the negatively charged non-transferred toner attached to the surface layer 16. As a result, the influence of the charge of the untransferred toner is suppressed, the overcharge of the member to be charged such as the photosensitive drum is suppressed, and the image failure is suppressed. The pKa of the compound of (c) may be determined by an ordinary titration method as a method of examining experimentally, and it is also possible to examine known values from the literature such as Chemical Handbook (edited by The Chemical Society of Japan <Maruzen Co., Ltd.>) It is. When the compound (c) is a polyvalent acid, pKa is the first-stage dissociation constant pKa 1 .
　（ｃ）の２５℃における水中の酸解離定数ｐＫａは、より好ましくは－５～１０の範囲内、さらに好ましくは－５～５の範囲内である。上記ｐＫａが－５以上であると、（ａ）のウレタン化反応や帯電ロール１０に対する酸の影響を抑えやすい。すなわち、（ａ）のウレタン化反応を阻害しにくく、また、帯電ロール１０の腐食等の不具合を抑えやすい。上記ｐＫａが１０以下であると、プロトン供与性により優れ、未転写トナーの電荷の影響を抑える効果により優れる。上記ｐＫａが５以下であると、プロトン供与性に特に優れ、未転写トナーの電荷の影響を抑える効果に特に優れる。 The acid dissociation constant pKa in water at 25 ° C. of (c) is more preferably in the range of −5 to 10, still more preferably in the range of −5 to 5. When the above pKa is -5 or more, the urethanation reaction of (a) and the influence of the acid on the charge roll 10 can be easily suppressed. That is, it is difficult to inhibit the urethanation reaction of (a), and it is easy to suppress defects such as corrosion of the charging roll 10. When the pKa is 10 or less, the proton donating property is more excellent, and the effect of suppressing the influence of the charge of the untransferred toner is more excellent. When the pKa is 5 or less, the proton donating property is particularly excellent, and the effect of suppressing the influence of the charge of the untransferred toner is particularly excellent.
　（ｃ）としては、有機酸、無機酸などが挙げられる。これらのうちでは、有機酸がより好ましい。有機酸は、無機酸と比較して（ａ）のウレタン化反応や帯電ロール１０に対する酸の影響を抑えやすい。無機酸としては、過塩素酸、硫酸、塩酸、リン酸、硝酸、ホウ酸などが挙げられる。有機酸としては、スルホン酸、カルボン酸などが挙げられる。スルホン酸としては、ｐ－トルエンスルホン酸、ｐ－フェノールスルホン酸、ベンゼンスルホン酸、メタンスルホン酸、１０－カンファ－スルホン酸などが挙げられる。カルボン酸としては、クエン酸、タンニン酸、安息香酸、シュウ酸、ギ酸、酢酸などが挙げられる。これらのうちでは、未転写トナーの電荷の影響を抑える効果に特に優れるなどの観点から、スルホン酸が特に好ましい。 Examples of (c) include organic acids and inorganic acids. Of these, organic acids are more preferred. The organic acid is easy to suppress the effect of the acid on the charging roll 10 and the urethanation reaction of (a) compared to the inorganic acid. Examples of inorganic acids include perchloric acid, sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid and boric acid. As the organic acid, sulfonic acid, carboxylic acid and the like can be mentioned. Examples of sulfonic acids include p-toluenesulfonic acid, p-phenolsulfonic acid, benzenesulfonic acid, methanesulfonic acid, 10-camphorsulfonic acid and the like. As carboxylic acid, citric acid, tannic acid, benzoic acid, oxalic acid, formic acid, acetic acid and the like can be mentioned. Among these, from the viewpoint of being particularly excellent in the effect of suppressing the influence of the charge of the untransferred toner, sulfonic acid is particularly preferable.
　（ｃ）の配合量は、（ａ）ウレタン製バインダー１００質量部に対し、１．０～１０質量部の範囲内であることが好ましい。より好ましくは３．０～８．０質量部の範囲内である。（ａ）ウレタン製バインダー１００質量部に対し、（ｃ）の配合量が１．０質量部以上であると、特に効率的にプロトンの受け渡しを行うことができる。また、（ｃ）の配合量が１０質量部以下であると、（ａ）のウレタン化反応や帯電ロール１０に対する酸の影響を抑えやすい。 The blending amount of (c) is preferably in the range of 1.0 to 10 parts by mass with respect to 100 parts by mass of the (a) urethane binder. More preferably, it is in the range of 3.0 to 8.0 parts by mass. With respect to 100 parts by mass of the (a) urethane binder, protons can be delivered particularly efficiently when the amount of (c) is 1.0 parts by mass or more. Moreover, it is easy to suppress the influence of the acid with respect to the urethanation reaction of (a) and the charging roll 10 as the compounding quantity of (c) is 10 mass parts or less.
　表層１６は、上記（ａ）をバインダーとして含有していればよく、他のポリマーからなるバインダーを含有してもよいし、含有していなくてもよい。他のポリマーからなるバインダーを含有する場合、上記（ａ）が表層１６のバインダーの主成分となるものであればよく、上記（ａ）が表層１６のバインダー全体の５０質量％以上であればよい。 The surface layer 16 may contain (a) as a binder, and may or may not contain a binder made of another polymer. When the binder containing other polymers is contained, the above (a) should just be a main component of the binder of surface layer 16, and the above (a) should be 50 mass% or more of the whole binder of surface 16 .
　表層１６は、上記（ａ）～（ｃ）に加え、本発明を阻害しない範囲において、必要に応じて、添加剤を含有していてもよい。添加剤としては、滑剤、加硫促進剤、老化防止剤、光安定剤、粘度調整剤、加工助剤、難燃剤、可塑剤、発泡剤、充填剤、分散剤、消泡剤、顔料、離型剤などが挙げられる。 In addition to the above (a) to (c), the surface layer 16 may contain an additive, if necessary, as long as the present invention is not inhibited. As additives, lubricants, vulcanization accelerators, anti-aging agents, light stabilizers, viscosity modifiers, processing aids, flame retardants, plasticizers, foaming agents, fillers, dispersants, antifoam agents, pigments, release agents A mold agent etc. are mentioned.
　表層１６は、表層形成用組成物を弾性体層１４の外周面に塗布・乾燥することにより形成することができる。表層形成用組成物は、上記ウレタン組成物、上記（ｂ）～（ｃ）を含む。また、必要に応じ、粗さ形成用粒子を含む。また、必要に応じ、表層に添加される各種添加剤を１種または２種以上含む。また、必要に応じ、溶媒を含む。 The surface layer 16 can be formed by applying and drying a surface layer forming composition on the outer peripheral surface of the elastic layer 14. The composition for forming a surface layer comprises the above urethane composition and the above (b) to (c). Moreover, the particle | grains for roughness formation are included as needed. In addition, it optionally contains one or more of various additives added to the surface layer. Moreover, the solvent is included as needed.
　表層１６の表面粗さは、上記範囲内に設定されており、トナーの粒径と同程度の大きさとなっている。これにより、表層１６に付着する未転写トナーとの接触面積が大きくなり、効率的にプロトンの受け渡しを行うことができる。表層１６の表面粗さＲｚが２０超であると、未転写トナーの電荷の影響が十分に抑えられず、画像不具合が抑えられない。また、表層１６に付着する未転写トナーとの接触面積をより大きくするなどの観点から、表層１６の表面粗さＲｚは、より好ましくは１．０～１５μｍの範囲内、さらに好ましくは３．０～１０μｍの範囲内である。表層１６の表面粗さＲｚは、十点平均粗さであり、ＪＩＳ　Ｂ０６０１（１９９４）に準拠して測定される。 The surface roughness of the surface layer 16 is set within the above range, and is about the same size as the particle diameter of the toner. As a result, the contact area with the untransferred toner adhering to the surface layer 16 is increased, and protons can be efficiently delivered. When the surface roughness Rz of the surface layer 16 is more than 20, the influence of the charge of the untransferred toner can not be sufficiently suppressed, and the image failure can not be suppressed. The surface roughness Rz of the surface layer 16 is more preferably in the range of 1.0 to 15 μm, and still more preferably 3.0, from the viewpoint of increasing the contact area with the untransferred toner attached to the surface layer 16 or the like. Within the range of ̃10 μm. The surface roughness Rz of the surface layer 16 is a ten-point average roughness, and is measured in accordance with JIS B 0601 (1994).
　表層１６の表面粗さは、公知の種々の方法により形成することができる。例えば、（ｂ）導電剤としての電子導電剤の粒径を調整することで所定の表面粗さに調整したり、所定の粒径の粗さ形成用粒子を表層１６に別途添加したり、型転写等の方法によって弾性体層１４の表面に表面凹凸を付与したりする方法などが挙げられる。これらのうちでは、粒径、配合量、液粘度などにより任意の粗さを形成できるなどの観点から、粗さ形成用粒子を表層１６に別途添加する方法がより好ましい。 The surface roughness of the surface layer 16 can be formed by various known methods. For example, (b) adjusting the particle diameter of the electron conductive agent as the conductive agent to adjust to a predetermined surface roughness, separately adding particles for forming a predetermined particle diameter to the surface layer 16, or There is a method of providing surface irregularities on the surface of the elastic layer 14 by a method such as transfer. Among these, a method of separately adding particles for roughness formation to the surface layer 16 is more preferable, from the viewpoint that an arbitrary roughness can be formed depending on the particle diameter, the blending amount, the liquid viscosity and the like.
　表層１６の表面硬度は、０．１～１０Ｎ／ｍｍ２の範囲内であることが好ましい。より好ましくは１．０～８．０Ｎ／ｍｍ２の範囲内、さらに好ましくは３．０～８．０Ｎ／ｍｍ２の範囲内である。表層１６の表面硬度が０．１Ｎ／ｍｍ２以上であると、過帯電現象の抑制機能により優れる。表層１６の表面硬度が１０Ｎ／ｍｍ２以下であると、トナーへのストレスを低減しやすい。表層１６の表面硬度は、マルテンス硬さで表すことができる。 The surface hardness of the surface layer 16 is preferably in the range of 0.1 to 10 N / mm 2 . More preferably, it is in the range of 1.0 to 8.0 N / mm 2 , more preferably in the range of 3.0 to 8.0 N / mm 2 . When the surface hardness of the surface layer 16 is 0.1 N / mm 2 or more, the overcharge phenomenon can be suppressed more effectively. When the surface hardness of the surface layer 16 is 10 N / mm 2 or less, stress on the toner can be easily reduced. The surface hardness of the surface layer 16 can be expressed by Martens hardness.
　表層１６の厚みは、特に限定されるものではないが、好ましくは３．０～２０μｍの範囲内、より好ましくは５．０～１５μｍの範囲内である。表層１６の厚みは、表面凹凸の凹部の平坦部における厚みである。表層１６の体積抵抗率は、特に限定されるものではないが、好ましくは１０４～１０９Ω・ｃｍ、より好ましくは１０５～１０８Ω・ｃｍ、さらに好ましくは１０６～１０７Ω・ｃｍの範囲内である。 The thickness of the surface layer 16 is not particularly limited, but is preferably in the range of 3.0 to 20 μm, more preferably in the range of 5.0 to 15 μm. The thickness of the surface layer 16 is the thickness at the flat portion of the concave portion of the surface unevenness. The volume resistivity of the surface layer 16 is not particularly limited, but is preferably 10 4 to 10 9 Ω · cm, more preferably 10 5 to 10 8 Ω · cm, still more preferably 10 6 to 10 7 Ω · It is in the range of cm.
　弾性体層１４は、ベースゴム（ポリマー成分）を含む。これにより、ゴム弾性を有する層となる。弾性体層１４は、ベースゴムを含有する導電性ゴム組成物により形成される。ベースゴム（架橋ゴム）は、未架橋ゴムを架橋することにより得られる。未架橋ゴムは、極性ゴムであってもよいし、非極性ゴムであってもよい。 The elastic layer 14 contains a base rubber (polymer component). Thereby, it becomes a layer which has rubber elasticity. The elastic layer 14 is formed of a conductive rubber composition containing a base rubber. The base rubber (crosslinked rubber) is obtained by crosslinking uncrosslinked rubber. The uncrosslinked rubber may be a polar rubber or a nonpolar rubber.
　極性ゴムは、極性基を有するゴムであり、極性基としては、クロロ基、ニトリル基、カルボキシル基、エポキシ基などを挙げることができる。極性ゴムとしては、具体的には、ヒドリンゴム、ニトリルゴム（ＮＢＲ）、ウレタンゴム（Ｕ）、アクリルゴム（アクリル酸エステルと２－クロロエチルビニルエーテルとの共重合体、ＡＣＭ）、クロロプレンゴム（ＣＲ）、エポキシ化天然ゴム（ＥＮＲ）などを挙げることができる。極性ゴムのうちでは、体積抵抗率が特に低くなりやすいなどの観点から、ヒドリンゴム、ニトリルゴム（ＮＢＲ）がより好ましい。 The polar rubber is a rubber having a polar group, and examples of the polar group include chloro group, nitrile group, carboxyl group and epoxy group. Specific examples of polar rubbers include hydrin rubber, nitrile rubber (NBR), urethane rubber (U), acrylic rubber (copolymer of acrylic ester and 2-chloroethyl vinyl ether, ACM), chloroprene rubber (CR) And epoxidized natural rubber (ENR). Among polar rubbers, a hydrin rubber and a nitrile rubber (NBR) are more preferable from the viewpoint that the volume resistivity tends to be particularly low.
　ヒドリンゴムとしては、エピクロルヒドリンの単独重合体（ＣＯ）、エピクロルヒドリン－エチレンオキサイド二元共重合体（ＥＣＯ）、エピクロルヒドリン－アリルグリシジルエーテル二元共重合体（ＧＣＯ）、エピクロルヒドリン－エチレンオキサイド－アリルグリシジルエーテル三元共重合体（ＧＥＣＯ）などを挙げることができる。 Examples of hydrin rubbers 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. can be mentioned.
　ウレタンゴムとしては、分子内にエーテル結合を有するポリエーテル型のウレタンゴムを挙げることができる。ポリエーテル型のウレタンゴムは、両末端にヒドロキシル基を有するポリエーテルとジイソシアネートとの反応により製造できる。ポリエーテルとしては、特に限定されるものではないが、ポリエチレングリコール、ポリプロピレングリコールなどを挙げることができる。ジイソシアネートとしては、特に限定されるものではないが、トリレンジイソシアネート、ジフェニルメタンジイソシアネートなどを挙げることができる。 As a urethane rubber, the polyether-type urethane rubber which has an ether bond in a molecule | numerator can be mentioned. The polyether type urethane rubber can be produced by the reaction of a polyether having a hydroxyl group at both ends with a diisocyanate. The polyether is not particularly limited, and polyethylene glycol, polypropylene glycol and the like can be mentioned. Although it does not specifically limit as diisocyanate, Tolylene diisocyanate, diphenylmethane diisocyanate etc. can be mentioned.
　非極性ゴムとしては、イソプレンゴム（ＩＲ）、天然ゴム（ＮＲ）、スチレンブタジエンゴム（ＳＢＲ）、ブタジエンゴム（ＢＲ）などが挙げられる。 Examples of nonpolar rubbers include isoprene rubber (IR), natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR) and the like.
　架橋剤としては、硫黄架橋剤、過酸化物架橋剤、脱塩素架橋剤を挙げることができる。これらの架橋剤は、単独で用いても良いし、２種以上組み合わせて用いても良い。 As a crosslinking agent, a sulfur crosslinking agent, a peroxide crosslinking agent, and a dechlorination crosslinking agent can be mentioned. These crosslinking agents may be used alone or in combination of two or more.
　硫黄架橋剤としては、粉末硫黄、沈降硫黄、コロイド硫黄、表面処理硫黄、不溶性硫黄、塩化硫黄、チウラム系加硫促進剤、高分子多硫化物などの従来より公知の硫黄架橋剤を挙げることができる。 Examples of sulfur crosslinking agents include conventionally known sulfur crosslinking agents such as powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur, sulfur chloride, thiuram vulcanization accelerator, and polymeric polysulfides. it can.
　過酸化物架橋剤としては、パーオキシケタール、ジアルキルパーオキサイド、パーオキシエステル、ケトンパーオキサイド、パーオキシジカーボネート、ジアシルパーオキサイド、ハイドロパーオキサイドなどの従来より公知の過酸化物架橋剤を挙げることができる。 Examples of peroxide crosslinking agents include conventionally known peroxide crosslinking agents such as peroxy ketals, dialkyl peroxides, peroxy esters, ketone peroxides, peroxy dicarbonates, diacyl peroxides and hydroperoxides. Can.
　脱塩素架橋剤としては、ジチオカーボネート化合物を挙げることができる。より具体的には、キノキサリン－２，３－ジチオカーボネート、６－メチルキノキサリン－２，３－ジチオカーボネート、６－イソプロピルキノキサリン－２，３－ジチオカーボネート、５，８－ジメチルキノキサリン－２，３－ジチオカーボネートなどを挙げることができる。 As a dechlorination crosslinking agent, a dithiocarbonate compound can be mentioned. More specifically, quinoxaline-2,3-dithiocarbonate, 6-methylquinoxaline-2,3-dithiocarbonate, 6-isopropylquinoxaline-2,3-dithiocarbonate, 5,8-dimethylquinoxaline-2,3- A dithio carbonate etc. can be mentioned.
　架橋剤の配合量としては、ブリードしにくいなどの観点から、未架橋ゴム１００質量部に対して、好ましくは０．１～２質量部の範囲内、より好ましくは０．３～１．８質量部の範囲内、さらに好ましくは０．５～１．５質量部の範囲内である。 The compounding amount of the crosslinking agent is preferably in the range of 0.1 to 2 parts by mass, more preferably 0.3 to 1.8 parts by mass with respect to 100 parts by mass of the non-crosslinked rubber from the viewpoint of hardly bleeding or the like. Within the range of part, more preferably within the range of 0.5 to 1.5 parts by mass.
　架橋剤として脱塩素架橋剤を用いる場合には、脱塩素架橋促進剤を併用しても良い。脱塩素架橋促進剤としては、１，８－ジアザビシクロ（５，４，０）ウンデセン－７（以下、ＤＢＵと略称する。）もしくはその弱酸塩を挙げることができる。脱塩素架橋促進剤は、ＤＢＵの形態として用いても良いが、その取り扱い面から、その弱酸塩の形態として用いることが好ましい。ＤＢＵの弱酸塩としては、炭酸塩、ステアリン酸塩、２－エチルヘキシル酸塩、安息香酸塩、サリチル酸塩、３－ヒドロキシ－２－ナフトエ酸塩、フェノール樹脂塩、２－メルカプトベンゾチアゾール塩、２－メルカプトベンズイミダゾール塩などを挙げることができる。 When a dechlorination crosslinking agent is used as the crosslinking agent, a dechlorination crosslinking accelerator may be used in combination. As a dechlorination crosslinking accelerator, 1,8-diazabicyclo (5,4,0) undecen-7 (hereinafter abbreviated as DBU) or a weak acid salt thereof can be mentioned. Although the dechlorination crosslinking accelerator may be used in the form of DBU, it is preferably used in the form of its weak acid salt from the viewpoint of its handling. As weak acid salts of DBU, carbonates, stearates, 2-ethylhexyl salts, benzoates, salicylates, 3-hydroxy-2-naphthoates, phenolic resin salts, 2-mercaptobenzothiazole salts, 2- Mercapto benzimidazole salts and the like can be mentioned.
　脱塩素架橋促進剤の含有量としては、ブリードしにくいなどの観点から、未架橋ゴム１００質量部に対して、０．１～２質量部の範囲内であることが好ましい。より好ましくは０．３～１．８質量部の範囲内、さらに好ましくは０．５～１．５質量部の範囲内である。 The content of the dechlorination crosslinking accelerator is preferably in the range of 0.1 to 2 parts by mass with respect to 100 parts by mass of the uncrosslinked rubber, from the viewpoint of hardly bleeding. More preferably, it is in the range of 0.3 to 1.8 parts by mass, still more preferably in the range of 0.5 to 1.5 parts by mass.
　弾性体層１４は、イオン導電剤、電子導電剤などの導電剤を含有してもよい。イオン導電剤、電子導電剤としては、表層１６において挙げられているものを好適に用いることができる。 The elastic layer 14 may contain a conductive agent such as an ion conductive agent or an electronic conductive agent. As the ion conductive agent and the electron conductive agent, those mentioned in the surface layer 16 can be suitably used.
　弾性体層１４には、必要に応じて、各種添加剤を適宜添加しても良い。添加剤としては、滑剤、加硫促進剤、老化防止剤、光安定剤、粘度調整剤、加工助剤、難燃剤、可塑剤、発泡剤、充填剤、分散剤、消泡剤、顔料、離型剤などを挙げることができる。 Various additives may be appropriately added to the elastic layer 14 as necessary. As additives, lubricants, vulcanization accelerators, anti-aging agents, light stabilizers, viscosity modifiers, processing aids, flame retardants, plasticizers, foaming agents, fillers, dispersants, antifoam agents, pigments, release agents Examples include molds and the like.
　弾性体層１４は、架橋ゴムの種類、イオン導電剤の配合量、電子導電剤の配合などにより、所定の体積抵抗率に調整することができる。弾性体層１４の体積抵抗率は、用途などに応じて１０２～１０１０Ω・ｃｍ、１０３～１０９Ω・ｃｍ、１０４～１０８Ω・ｃｍの範囲などに適宜設定すればよい。 The elastic layer 14 can be adjusted to a predetermined volume resistivity by the type of crosslinked rubber, the compounding amount of the ion conductive agent, the compounding of the electron conductive agent, and the like. The volume resistivity of the elastic layer 14 may be appropriately set in the range of 10 2 to 10 10 Ω · cm, 10 3 to 10 9 Ω · cm, 10 4 to 10 8 Ω · cm, etc. depending on the application etc. .
　弾性体層１４の厚みは、特に限定されるものではなく、用途などに応じて０．１～１０ｍｍの範囲内などで適宜設定すればよい。弾性体層１４は、発泡体であってもよいし、非発泡体であってもよい。 The thickness of the elastic layer 14 is not particularly limited, and may be appropriately set in the range of 0.1 to 10 mm according to the application and the like. The elastic layer 14 may be foam or non-foam.
　弾性体層１４は、例えば、次のようにして製造することができる。まず、軸体１２をロール成形金型の中空部に同軸的に設置し、未架橋の導電性ゴム組成物を注入して、加熱・硬化（架橋）させた後、脱型するか、あるいは、軸体１２の表面に未架橋の導電性ゴム組成物を押出成形するなどにより、軸体１２の外周に弾性体層１４を形成する。 The elastic layer 14 can be manufactured, for example, as follows. First, the shaft 12 is coaxially installed in the hollow portion of the roll forming mold, and the uncrosslinked conductive rubber composition is injected, heated and cured (crosslinked), and then removed or The elastic layer 14 is formed on the outer periphery of the shaft 12 by extruding an uncrosslinked conductive rubber composition on the surface of the shaft 12 or the like.
　軸体１２は、導電性を有するものであれば特に限定されない。具体的には、鉄、ステンレス、アルミニウムなどの金属製の中実体、中空体からなる芯金などを例示することができる。軸体１２の表面には、必要に応じて、接着剤、プライマーなどを塗布しても良い。つまり、弾性体層１４は、接着剤層（プライマー層）を介して軸体１２に接着されていてもよい。接着剤、プライマーなどには、必要に応じて導電化を行なっても良い。 The shaft 12 is not particularly limited as long as it has conductivity. Specifically, a solid body made of metal such as iron, stainless steel, or aluminum, a cored bar made of a hollow body, and the like can be exemplified. An adhesive, a primer or the like may be applied to the surface of the shaft 12 as necessary. That is, the elastic layer 14 may be bonded to the shaft 12 via the adhesive layer (primer layer). The adhesive, the primer, etc. may be made conductive as required.
　以上の構成の帯電ロール１０によれば、表層１６が上記（ａ）～（ｃ）を含有し、かつ、表層１６の表面粗さＲｚが１．０～２０μｍの範囲内であることで、未転写トナーが付着する帯電ロール１０による感光ドラムの帯電時に帯電量を調整し、未転写トナーの電荷による感光ドラムの過帯電現象が抑えられる。そして、これによる画像不具合が抑えられる。表層１６がウレタン製バインダーを含有することで、上記効果が得られる。表層１６がウレタン製バインダーを含有せず他のポリマー製バインダーのみ含有するものであると、上記効果は得られない。 According to the charging roll 10 having the above configuration, the surface layer 16 contains the above (a) to (c), and the surface roughness Rz of the surface layer 16 is in the range of 1.0 to 20 μm. The charge amount is adjusted when the photosensitive drum is charged by the charging roll 10 to which the transfer toner adheres, and the overcharge phenomenon of the photosensitive drum due to the charge of the non-transfer toner can be suppressed. And the image defect by this is suppressed. The above effect is obtained when the surface layer 16 contains a urethane binder. If the surface layer 16 does not contain a urethane binder but contains only another polymer binder, the above effect can not be obtained.
　本発明に係る帯電ロールの構成としては、図１に示す構成に限定されるものではない。例えば、図１に示す帯電ロール１０において、軸体１２と弾性体層１４との間に他の弾性体層を備えた構成であってもよい。この場合、他の弾性体層は、帯電ロールのベースとなる層であり、弾性体層１４が帯電ロールの抵抗調整を行う抵抗調整層などとして機能する。他の弾性体層は、例えば、弾性体層１４を構成する材料として挙げられた材料のいずれかにより構成することができる。また、例えば、図１に示す帯電ロール１０において、弾性体層１４と表層１６との間に他の弾性体層を備えた構成であってもよい。この場合、弾性体層１４が帯電ロールのベースとなる層であり、他の弾性体層は、帯電ロールの抵抗調整を行う抵抗調整層などとして機能する。 The configuration of the charging roll according to the present invention is not limited to the configuration shown in FIG. For example, in the charging roll 10 shown in FIG. 1, another elastic layer may be provided between the shaft 12 and the elastic layer 14. In this case, the other elastic layer is a layer to be a base of the charging roll, and the elastic layer 14 functions as a resistance adjusting layer or the like for adjusting the resistance of the charging roll. The other elastic layer can be made of, for example, any of the materials mentioned as the material of the elastic layer 14. Also, for example, in the charging roll 10 shown in FIG. 1, another elastic layer may be provided between the elastic layer 14 and the surface layer 16. In this case, the elastic layer 14 is a layer to be a base of the charging roll, and the other elastic layers function as a resistance adjusting layer or the like for adjusting the resistance of the charging roll.
　以下、実施例および比較例を用いて本発明を詳細に説明する。 Hereinafter, the present invention will be described in detail using examples and comparative examples.
（実施例１～７）
＜導電性ゴム組成物の調製＞
　イソプレンゴム１００質量部に対し、カーボンブラック３０質量部、酸化亜鉛６質量部、ステアリン酸２質量部、硫黄１質量部、チアゾール系加硫促進剤０．５質量部、チラウム系加硫促進剤０．５質量部、重質炭酸カルシウム５０質量部を配合し、５０℃に温度調節した密閉型ミキサーを用いて１０分間混練し、導電性ゴム組成物を調製した。 (Examples 1 to 7)
<Preparation of Conductive Rubber Composition>
Based on 100 parts by mass of isoprene rubber, 30 parts by mass of carbon black, 6 parts by mass of zinc oxide, 2 parts by mass of stearic acid, 1 part by mass of sulfur, 0.5 parts by mass of thiazole based vulcanization accelerator, 0 thiraum based vulcanization accelerator A conductive rubber composition was prepared by blending 5 parts by mass and 50 parts by mass of ground calcium carbonate, and kneading for 10 minutes using a closed-type mixer whose temperature was adjusted to 50 ° C.
　導電性ゴム組成物の材料として、以下の材料を準備した。
・ゴム成分
　イソプレンゴム（ＩＲ）［ＪＳＲ（株）製、「ＪＳＲ　ＩＲ２２００」］
・導電剤
　カーボンブラック（電子導電剤）［キャボットジャパン（株）製、「ショウブラックＮ７６２」］
・酸化亜鉛［堺化学工業（株）製、「酸化亜鉛２種」］
・ステアリン酸［日本油脂（株）製、「ステアリン酸さくら」］
・硫黄［鶴見化学工業（株）製、「粉末硫黄」］
・加硫促進剤
　チアゾール系加硫促進剤［大内新興化学工業（株）製、「ノクセラーＤＭ」］
　チラウム系加硫促進剤［大内新興化学工業（株）製、「ノクセラーＴＲＡ」］
・無機フィラー粒子
　重質炭酸カルシウム［白石カルシウム（株）製、「ホワイトンＢ」、平均粒径３．６μｍ］ The following materials were prepared as materials for the conductive rubber composition.
-Rubber component Isoprene rubber (IR) [manufactured by JSR Corp., "JSR IR 2200"]
・ Conductive agent carbon black (electronic conductive agent) [Cabot Japan KK, "Show Black N762"]
・ Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., “Zinc oxide 2”)
・ Stearic acid (manufactured by NOF Corp., "Stearic Acid Sakura")
・ Sulfur [made by Tsurumi Chemical Industries, Ltd., "powdered sulfur"]
・ Vulcanization accelerator Thiazole-based vulcanization accelerator [Ouchi Shinko Chemical Co., Ltd. product, "Noxceller DM"]
Thiraum-based vulcanization accelerator [Ouchi Shinko Chemical Co., Ltd. product, "Nocceller TRA"]
· Inorganic filler particles Heavy calcium carbonate [Shiroishi Calcium Co., Ltd., "Whiteton B", average particle size 3.6 μm]
＜弾性体層の作製＞
　直径６ｍｍ、快削鋼（ＳＵＭ）製の芯金の外周に、押出成形装置を用いて、調製した導電性ゴム組成物をクラウン形状に押出成形した。具体的には、押出成形装置のダイスの円形口部に対して上記芯金を通過させながら、ダイスと芯金との隙間に導電性ゴム組成物を供給することにより、芯金の外周に弾性体層を押出成形した。この押出成形の際、芯金の通過速度を変化させ、芯金の長手方向に対する導電性ゴム組成物の付着量を制御することにより、弾性体層前駆体の形状をクラウン形状とした。次いで、これを１８０℃で３０分間加熱処理した。これにより芯金の外周に所定の弾性体層（厚み１．５ｍｍ）を形成した。 <Production of elastic layer>
Using an extrusion molding apparatus, the prepared conductive rubber composition was extruded into a crown shape around the periphery of a core metal made of free-cutting steel (SUM) with a diameter of 6 mm. Specifically, the conductive rubber composition is supplied to the gap between the die and the cored bar while passing the cored bar to the circular opening of the die of the extrusion molding apparatus, whereby the outer periphery of the cored bar is made elastic. The body layer was extruded. At the time of this extrusion molding, the shape of the elastic layer precursor is made into a crown shape by changing the passing speed of the core metal and controlling the adhesion amount of the conductive rubber composition in the longitudinal direction of the core metal. It was then heat treated at 180 ° C. for 30 minutes. Thereby, a predetermined elastic layer (thickness 1.5 mm) was formed on the outer periphery of the cored bar.
＜表層の作製＞
　表１に記載の配合量（質量部）となるように、ウレタン樹脂、ポリオール、イソシアネート、硬化触媒、導電剤、粗さ形成用粒子、所定のｐＫａの添加剤を配合し、メチルエチルケトン（ＭＥＫ）２００質量部を加え、所定時間、超音波をかけて混合攪拌することにより、表層形成用の液状組成物を調製した。次いで、この液状組成物を弾性体層の外周面にロールコートし、熱処理を施すことにより、弾性体層の外周に表層（厚み１０μｍ）を形成した。これにより、帯電ロールを作製した。表面粗さＲｚは、粗さ形成用粒子の種類（粒径）を変えることにより調整した。 <Preparation of surface>
A methyl ethyl ketone (MEK) 200 is blended with a urethane resin, a polyol, an isocyanate, a curing catalyst, a conductive agent, particles for roughness formation, and an additive having a predetermined pKa so that the blending amount (parts by mass) described in Table 1 is obtained. The liquid composition for surface layer formation was prepared by adding a mass part and carrying out ultrasonic mixing and mixing and stirring for a predetermined time. Next, the liquid composition was roll-coated on the outer peripheral surface of the elastic layer and heat treated to form a surface layer (10 μm in thickness) on the outer periphery of the elastic layer. Thereby, a charging roll was produced. The surface roughness Rz was adjusted by changing the type (particle diameter) of the roughness-forming particles.
（実施例８～９）
　表層の作製において、表層の厚み（表層形成用の液状組成物の液粘度）を変えることにより、表面硬度を調整した。これ以外は実施例１～７と同様にして帯電ロールを作製した。 (Examples 8 to 9)
In the preparation of the surface layer, the surface hardness was adjusted by changing the thickness of the surface layer (liquid viscosity of the liquid composition for forming the surface layer). A charging roll was produced in the same manner as in Examples 1 to 7 except for the above.
（比較例１）
　表層の作製において、バインダー＜１＞（ウレタン樹脂）に代えてバインダー＜４＞（ウレタン樹脂）を用い、所定のｐＫａの添加剤を配合しなかった以外は実施例３と同様にして帯電ロールを作製した。 (Comparative example 1)
In the preparation of the surface layer, in the same manner as in Example 3 except that the binder <1> (urethane resin) was replaced with the binder <4> (urethane resin) and the additive having a predetermined pKa was not blended. Made.
（比較例２）
　表層の作製において、所定のｐＫａの添加剤としてｐＫａ＝２５のエステルを用いた以外は実施例３と同様にして帯電ロールを作製した。 (Comparative example 2)
In the preparation of the surface layer, a charge roll was prepared in the same manner as in Example 3 except that an ester of pKa = 25 was used as an additive of predetermined pKa.
（比較例３～４）
　表層の作製において、バインダー＜１＞（ウレタン樹脂）に代えてバインダー＜２＞（アクリル樹脂）あるいはバインダー＜３＞（ナイロン樹脂）を用いた以外は実施例３と同様にして帯電ロールを作製した。 (Comparative examples 3 to 4)
In the preparation of the surface layer, a charge roll was prepared in the same manner as Example 3, except that the binder <2> (acrylic resin) or the binder <3> (nylon resin) was used instead of the binder <1> (urethane resin). .
（比較例５）
　表層の作製において、表面粗さＲｚを２５．０μｍとした以外は実施例３と同様にして帯電ロールを作製した。 (Comparative example 5)
In the preparation of the surface layer, a charge roll was prepared in the same manner as Example 3, except that the surface roughness Rz was 25.0 μm.
（比較例６）
　表層の作製において、導電剤を配合しなかった以外は実施例３と同様にして帯電ロールを作製した。 (Comparative example 6)
In the preparation of the surface layer, a charge roll was prepared in the same manner as in Example 3 except that the conductive agent was not blended.
　表層材料として用いた材料は以下の通りである。
・ウレタン樹脂（１）：東ソー製「ニッポラン５１９６」
・アクリル樹脂：根上工業製「パラクロンＷ１９７Ｃ」
・ナイロン樹脂：ナガセケムテック製「ＥＦ３０Ｔ」
・ウレタン樹脂（２）：東洋紡製「ＵＲ－１３５０」
・ポリオール：ＡＤＥＫＡ社製「アデカポリエーテルＰ－１０００」
・イソシアネート：東ソー社製「コロネートＨＸ」
・硬化触媒：楠本化成社製「Ｋ－ＫＡＴ　ＸＫ－６３５」
・導電剤＜１＞：カーボンブラック、ライオン製「ケッチェンＥＣ３００Ｊ」
・導電剤＜２＞：イオン導電剤、テトラメチルアンモニウムクロリド（試薬）
・粗さ形成用粒子＜１＞：アクリル粒子、平均粒径１．０μｍ、積水化成品工業製「テクポリマーＳＳＸ－１０１」
・粗さ形成用粒子＜２＞：ウレタン粒子、平均粒径２２．０μｍ、根上工業製「アートパールＣ３００」
・粗さ形成用粒子＜３＞：アクリル粒子、平均粒径５．０μｍ、綜研化学製「ＭＸ－５００」
・スルホン酸：ｐ－トルエンスルホン酸（ｐＫａ＝－２．８）
・クエン酸：ｐＫａ（ｐＫａ１）＝３．１
・タンニン酸：試薬、ｐＫａ＝１０
・過塩素酸：試薬、ｐＫａ＝－１０
・カルボン酸エステル：試薬、ｐＫａ＝２５ The materials used as the surface layer material are as follows.
-Urethane resin (1): Tosoh "Nipporan 5196"
・ Acrylic resin: "Parakron W197C" manufactured by Negami Chemical Industries, Ltd.
-Nylon resin: Nagase Chemtech "EF30T"
-Urethane resin (2): Toyobo "UR-1350"
-Polyol: "ADEKA POLYETHER P-1000" manufactured by ADEKA
・ Isocyanate: Toronso "Corronate HX"
Curing catalyst: "K-KAT XK-635" manufactured by Enomoto Chemical Co., Ltd.
・ Conductive agent <1>: Carbon black, manufactured by Lion "Ketjen EC300J"
・ Conductive agent <2>: Ion conductive agent, tetramethyl ammonium chloride (reagent)
· Roughness-forming particles <1>: Acrylic particles, average particle size 1.0 μm, Sekisui Plastics Co., Ltd. "Techpolymer SSX-101"
· Roughness-forming particles <2>: Urethane particles, average particle diameter 22.0 μm, manufactured by Negami Industrial Co., Ltd. "Art Pearl C300"
· Roughness-forming particles <3>: Acrylic particles, average particle diameter 5.0 μm, "MX-500" manufactured by Soken Chemical & Chemical Co., Ltd.
Sulfonic acid: p-toluenesulfonic acid (pKa = -2.8)
Citric acid: pKa (pKa 1 ) = 3.1
· Tannic acid: reagent, pKa = 10
Perchloric acid: reagent, pKa = -10
・ Carboxyl ester: reagent, pKa = 25
　作製した各帯電ロールについて、表面硬度、帯電量を測定した。また、画像評価を行った。評価結果および表層形成用組成物の配合組成を以下の表に示す。 The surface hardness and the charge amount were measured for each of the produced charging rolls. Also, image evaluation was performed. The evaluation results and the composition of the surface layer forming composition are shown in the following table.
（表面硬度の測定）
　ユニバーサル硬度計（フィッシャー製「フィッシャースコープＨ１００」を用い、帯電ロールの表層の表面から５ｍＮ／３０秒の定荷重にて触針を押し込み、表層のマルテンス硬さを測定した。 (Measurement of surface hardness)
Using a universal hardness tester (Fisher's "Fisher Scope H100"), the stylus was pushed in from the surface of the surface of the charge roll with a constant load of 5 mN / 30 seconds, and the Martens hardness of the surface was measured.
（帯電量の測定）
　図２に示すように、回転治具６にＨＰ社製「ＣＬＪ４５２５ｄｎ」カートリッジの感光ドラム１を組み付け、その上に各帯電ロール２を接触させ、帯電ロール２の両端に合わせて１ｋｇの荷重を負荷した。この際、全体をボックスで囲んで遮光した。帯電ロール２に接続した高圧電源３から－１．０ＫＶの直流電圧のみを印加し、感光ドラム１を１周回転させた後のドラム電位を、高圧プローブ４を備えた表面電位計５により測定した。 (Measurement of charge amount)
As shown in FIG. 2, the photosensitive drum 1 of the “CLJ 4525 dn” cartridge made by HP is assembled to the rotating jig 6, and the charging rolls 2 are brought into contact thereon, and a load of 1 kg is loaded according to the both ends of the charging roll 2. did. At this time, the whole was surrounded by a box and shielded from light. Only a DC voltage of -1.0 KV was applied from the high voltage power supply 3 connected to the charging roll 2, and the drum potential after rotating the photosensitive drum 1 once was measured by the surface voltmeter 5 equipped with the high voltage probe 4. .
（帯電量差）
　電極を遮断し、白地を印刷することで意図的に帯電ロール表面にトナーカブリを引き起こした。その後、上記帯電量の測定と同様に帯電量の測定を行った。トナーカブリがないときの帯電量の値を基準とし、トナーカブリ時の帯電量の値との差を算出した。 (Charge amount difference)
By blocking the electrode and printing a white background, toner fogging was intentionally caused on the charging roll surface. Thereafter, the charge amount was measured in the same manner as the measurement of the charge amount. Based on the value of the charge amount when there was no toner fog, the difference from the value of the charge amount at the toner fog was calculated.
（画像評価）
　作製した導電性ロールを実機（ＨＰ製「ＣＬＪ４５２５ｄｎ」）のカートリッジ（ブラック）に取り付け、１５℃×１０％ＲＨ環境下にて２５％濃度ハーフトーンにて画出しを行った。画像にムラがなかったものを特に良好「◎」、画像にムラがほとんどなかったものを良好「○」、画像にムラが多かったものを不良「×」とした。 (Image evaluation)
The produced conductive roll was attached to a cartridge (black) of a real machine (“CLJ 4525 dn” manufactured by HP), and image formation was performed with a 25% density halftone under an environment of 15 ° C. × 10% RH. Those with no unevenness in the image were particularly good "◎", those with little unevenness in the image were good "○", and those with many unevenness in the image were considered "Defective""×".
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　実施例から、帯電ロールの表層が（ａ）ウレタン製バインダー、（ｂ）導電剤、（ｃ）２５℃における水中の酸解離定数ｐＫａが－１０～１５の範囲内のプロトン供与性物質を含有し、かつ、表層の表面粗さＲｚが１．０～２０μｍの範囲内であると、トナーカブリがないときの帯電量とトナーカブリ時の帯電量との差が小さいことがわかる。これは、上記（ｃ）によって未転写トナーが付着する帯電ロールによる感光ドラムの帯電時に帯電量が調整されているためと推察される。これにより、未転写トナーの電荷による感光ドラムの過帯電現象が抑えられるため、画像不具合が抑えられている。 From the examples, the surface layer of the charge roll contains (a) a urethane binder, (b) a conductive agent, and (c) a proton donating substance having an acid dissociation constant pKa in water at 25 ° C. in the range of -10 to 15. Also, it is found that when the surface roughness Rz of the surface layer is in the range of 1.0 to 20 μm, the difference between the charge amount when there is no toner fog and the charge amount when toner fog is small. The reason is presumed to be that the charge amount is adjusted at the time of charging of the photosensitive drum by the charging roll to which the non-transferred toner adheres from the above (c). As a result, the overcharging phenomenon of the photosensitive drum due to the charge of the non-transferred toner can be suppressed, so that the image failure can be suppressed.
　比較例１、２のように、表層が上記（ｃ）を含有していないと、トナーカブリがないときの帯電量とトナーカブリ時の帯電量との差が大きく、未転写トナーの電荷による感光ドラムの過帯電現象が抑えられていない。このため、画像不具合が発生している。比較例３、４のように、表層のバインダーがウレタン製バインダーではないと、上記（ｃ）を表層に添加することでトナーカブリがないときの帯電量とトナーカブリ時の帯電量との差を小さくする効果が得られず、未転写トナーの電荷による感光ドラムの過帯電現象が抑えられていない。このため、画像不具合が発生している。比較例５のように、表層の表面粗さＲｚが所定範囲外であると、トナーカブリがないときの帯電量とトナーカブリ時の帯電量との差が大きく、未転写トナーの電荷による感光ドラムの過帯電現象が抑えられていない。このため、画像不具合が発生している。比較例６のように、表層が導電剤を含有していないと、感光ドラムを帯電させることができない。 As in Comparative Examples 1 and 2, when the surface layer does not contain the above (c), the difference between the charge amount when toner fog does not occur and the charge amount when toner fog is large is large. The overcharge phenomenon of the drum is not suppressed. Therefore, an image failure has occurred. As in Comparative Examples 3 and 4, when the binder in the surface layer is not a urethane binder, the difference between the charge amount when there is no toner fog and the charge amount at the toner fog by adding the above (c) to the surface layer is The effect of reducing the size is not obtained, and the overcharge phenomenon of the photosensitive drum due to the charge of the non-transfer toner is not suppressed. Therefore, an image failure has occurred. As in Comparative Example 5, when the surface roughness Rz of the surface layer is out of the predetermined range, the difference between the charge amount when there is no toner fog and the charge amount when toner fog is large, and the photosensitive drum by the charge of untransferred toner Overcharge phenomenon is not suppressed. Therefore, an image failure has occurred. As in Comparative Example 6, when the surface layer does not contain a conductive agent, the photosensitive drum can not be charged.
　そして、実施例から、表層の表面粗さＲｚが３．０～１０μｍであると、トナーカブリがないときの帯電量とトナーカブリ時の帯電量との差が特に小さく、画像評価が特に良好である。また、上記（ｃ）がスルホン酸であると、トナーカブリがないときの帯電量とトナーカブリ時の帯電量との差が特に小さく、画像評価が特に良好である。 From the examples, when the surface roughness Rz of the surface layer is 3.0 to 10 μm, the difference between the charge amount when there is no toner fog and the charge amount when toner fog is particularly small, and the image evaluation is particularly good. is there. When (c) is sulfonic acid, the difference between the charge amount when no toner fog occurs and the charge amount when toner fog occurs is particularly small, and the image evaluation is particularly good.
　以上、本発明の実施形態・実施例について説明したが、本発明は上記実施形態・実施例に何ら限定されるものではなく、本発明の趣旨を逸脱しない範囲内で種々の改変が可能である。 As mentioned above, although embodiment and Example of this invention were described, this invention is not limited at all to the said embodiment and Example, A various change is possible within the range which does not deviate from the meaning of this invention .

Claims (8)

  1. 　弾性体層と、前記弾性体層の外周に形成された表層と、を備え、
    　前記表層が下記（ａ）～（ｃ）を含有し、かつ、前記表層の表面粗さＲｚが１．０～２０μｍの範囲内であることを特徴とする電子写真機器用帯電部材。
    （ａ）ウレタン製バインダー
    （ｂ）導電剤
    （ｃ）２５℃における水中の酸解離定数ｐＫａが－１０～１５の範囲内のプロトン供与性物質     An elastic layer, and a surface layer formed on the outer periphery of the elastic layer;
    A charging member for an electrophotographic apparatus, wherein the surface layer contains the following (a) to (c), and the surface roughness Rz of the surface layer is in a range of 1.0 to 20 μm.
    (A) urethane binder (b) conductive agent (c) proton donating substance having an acid dissociation constant pKa in water at 25 ° C. in the range of -10 to 15
  2. 　前記（ｃ）は、２５℃における水中の酸解離定数ｐＫａが－５～１０の範囲内の化合物であることを特徴とする請求項１に記載の電子写真機器用帯電部材。 2. The charging member for an electrophotographic apparatus according to claim 1, wherein (c) is a compound having an acid dissociation constant pKa in water at 25 ° C. in the range of −5 to 10.
  3. 　前記（ｃ）は、２５℃における水中の酸解離定数ｐＫａが－１０～５の範囲内の化合物であることを特徴とする請求項１に記載の電子写真機器用帯電部材。 2. The charging member for an electrophotographic apparatus according to claim 1, wherein (c) is a compound having an acid dissociation constant pKa in water at 25 ° C. in the range of −10 to 5.
  4. 　前記（ｃ）が、有機酸であることを特徴とする請求項１から３のいずれか１項に記載の電子写真機器用帯電部材。 The charging member for an electrophotographic apparatus according to any one of claims 1 to 3, wherein (c) is an organic acid.
  5. 　前記（ｃ）が、スルホン酸であることを特徴とする請求項４に記載の電子写真機器用帯電部材。 5. The charging member for an electrophotographic apparatus according to claim 4, wherein (c) is a sulfonic acid.
  6. 　前記（ｂ）が、カーボンブラックであることを特徴とする請求項１から５のいずれか１項に記載の電子写真機器用帯電部材。 The electrophotographic apparatus charging member according to any one of claims 1 to 5, wherein (b) is carbon black.
  7. 　前記（ａ）の硬化触媒が、金属系触媒であることを特徴とする請求項１から６のいずれか１項に記載の電子写真機器用帯電部材。 The charging member for an electrophotographic apparatus according to any one of claims 1 to 6, wherein the curing catalyst (a) is a metal-based catalyst.
  8. 　前記表層の表面硬度が、０．１～１０Ｎ／ｍｍ２の範囲内であることを特徴とする請求項１から７のいずれか１項に記載の電子写真機器用帯電部材。 The surface layer of the surface hardness, 0.1 to electrophotographic equipment charging member according to any one of claims 1 7, characterized in that in the range of 10 N / mm 2.
PCT/JP2018/023772 2017-08-31 2018-06-22 Charging member for electrophotographic apparatuses WO2019044137A1 (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005315979A (en) * 2004-04-27 2005-11-10 Canon Inc Conductive member, process cartridge, and image forming apparatus
JP2010231078A (en) * 2009-03-27 2010-10-14 Fuji Xerox Co Ltd Image forming apparatus
US20110052252A1 (en) * 2009-08-27 2011-03-03 Xerox Corporation Bias charging overcoat
JP2016110126A (en) * 2014-11-28 2016-06-20 キヤノン株式会社 Electronic photography member, process cartridge, and image formation device
JP2016110061A (en) * 2014-07-25 2016-06-20 キヤノン株式会社 Cartridge and image forming apparatus
JP2017032821A (en) * 2015-08-03 2017-02-09 株式会社ブリヂストン Charging roller

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005315979A (en) * 2004-04-27 2005-11-10 Canon Inc Conductive member, process cartridge, and image forming apparatus
JP2010231078A (en) * 2009-03-27 2010-10-14 Fuji Xerox Co Ltd Image forming apparatus
US20110052252A1 (en) * 2009-08-27 2011-03-03 Xerox Corporation Bias charging overcoat
JP2016110061A (en) * 2014-07-25 2016-06-20 キヤノン株式会社 Cartridge and image forming apparatus
JP2016110126A (en) * 2014-11-28 2016-06-20 キヤノン株式会社 Electronic photography member, process cartridge, and image formation device
JP2017032821A (en) * 2015-08-03 2017-02-09 株式会社ブリヂストン Charging roller

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