WO2019044137A1 - 電子写真機器用帯電部材 - Google Patents

電子写真機器用帯電部材 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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English (en)
French (fr)
Japanese (ja)
Inventor
健太 中里
井上　大輔
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Sumitomo Riko Co Ltd
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Sumitomo Riko Co Ltd
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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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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
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JP2021189208A (ja) * 2020-05-26 2021-12-13 住友理工株式会社 電子写真機器用帯電ロール

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005315979A (ja) * 2004-04-27 2005-11-10 Canon Inc 導電性部材、プロセスカートリッジ及び画像形成装置
JP2010231078A (ja) * 2009-03-27 2010-10-14 Fuji Xerox Co Ltd 画像形成装置
US20110052252A1 (en) * 2009-08-27 2011-03-03 Xerox Corporation Bias charging overcoat
JP2016110061A (ja) * 2014-07-25 2016-06-20 キヤノン株式会社 カートリッジおよび画像形成装置
JP2016110126A (ja) * 2014-11-28 2016-06-20 キヤノン株式会社 電子写真用部材、プロセスカートリッジおよび画像形成装置
JP2017032821A (ja) * 2015-08-03 2017-02-09 株式会社ブリヂストン 帯電ローラ

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005315979A (ja) * 2004-04-27 2005-11-10 Canon Inc 導電性部材、プロセスカートリッジ及び画像形成装置
JP2010231078A (ja) * 2009-03-27 2010-10-14 Fuji Xerox Co Ltd 画像形成装置
US20110052252A1 (en) * 2009-08-27 2011-03-03 Xerox Corporation Bias charging overcoat
JP2016110061A (ja) * 2014-07-25 2016-06-20 キヤノン株式会社 カートリッジおよび画像形成装置
JP2016110126A (ja) * 2014-11-28 2016-06-20 キヤノン株式会社 電子写真用部材、プロセスカートリッジおよび画像形成装置
JP2017032821A (ja) * 2015-08-03 2017-02-09 株式会社ブリヂストン 帯電ローラ

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