JP2018091883A - Conductive roller - Google Patents

Abstract

SOLUTION: There is provided a conductive roller having a base layer and a surface layer on an outer peripheral surface of a shaft, where the surface layer is formed so as to contain a resin as a main material, and a main chain or a terminal portion of the resin is chemically bonded to a heterocyclic aromatic group having an amidinium group.EFFECT: A resistance value of a surface of a developing roller can be set at a desired value, and frictional electrification of the developing roller and a toner can be suppressed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a conductive roller such as a developing roller and a toner supply roller used in an electrophotographic apparatus.

  Conventionally, a polyurethane foam is often used as a base layer (elastic layer) in conductive rollers such as a developing roller and a toner supply roller used in an electrophotographic apparatus. In particular, in the case of a developing roller, usually, the surface state of the roller is often adjusted by coating and forming a surface resin layer constituting the roller surface on the elastic layer made of this polyurethane foam.

  In the electrophotographic printing process, in the developing process, first, the toner sandwiched between the toner supply roller and the developing roller is frictionally charged by friction generated between the toner supply roller and the developing roller. A predetermined voltage is applied to the developing roller and the toner supply roller so that the toner is attracted to the developing roller side. The toner supplied to the developing roller is held on the roller surface, and is formed in a thin layer when passing through the contact portion with the stratification (layer regulation) blade. The toner is charged by friction with the stratification blade and the developing roller. Next, the toner formed in the thin layer is conveyed to the contact portion with the photosensitive drum by the rotation of the developing roller. Between the photosensitive drum and the developing roller, the toner moves to the photosensitive drum side in the portion irradiated with light in the exposure process, and the toner is held on the developing roller side in the portion not irradiated with light. An electric field is formed.

  In a member such as a developing roller, in order to have conductivity, various conductive agents and electrolytes are often added to and mixed with a polymer material. When using materials, not only the stability of resistance but also the surface resistance of the developing roller must be set to a desired value, and a conductive polymer material that can suppress frictional charging between the developing roller and the toner is required. Is done.

  In the technique described in Japanese Patent Application Laid-Open No. 2014-133853, a proposal has been made to incorporate a quaternary ammonium salt as an electrolyte cation into the main chain of the polymer material as a conductive polymer material.

JP 2014-133853 A

  However, when the above-described proposed conductive polymer member is applied to the developing roller, a desired resistance value required for the developing roller cannot be obtained, and frictional charging cannot be sufficiently suppressed. As a result, an image defect or the like is caused, and further improvement is necessary to reliably obtain an image that is good for a long time. In particular, there is a problem that excessive triboelectric charging occurs because static electricity is easily held in a low temperature and low humidity environment.

  The present invention has been made in view of the above circumstances, and allows the resistance value on the surface of the developing roller to be a desired value, and frictional charging between the developing roller and the toner can be suppressed as much as possible. An object of the present invention is to provide a developing roller capable of reliably obtaining the toner for a long period of time.

  As a result of intensive studies in order to achieve the above object, the present inventor has found that the main chain or the terminal portion of the resin used as a base material is a complex having an amidinium group as a material for the surface layer of a conductive rotor such as a developing roller. The chemical resistance of the ring aromatic group, and preferably the addition of an electronic conductive agent to the resin material allows the resistance value of the surface of the conductive roller to be set to a desired value. It has been found that the triboelectric charging can be suppressed, and the present invention has been made.

  That is, in the present invention, as a material for the surface layer of a conductive roller such as a developing roller, a heterocyclic aromatic group having an amidinium group such as an imidazole ring is incorporated into the main chain of the polymer, preferably a sulfonimide as an anion. By adding an ion, more preferably by adding carbon black, the amidinium group is cyclic, so that the solubility of the substance in the resin can be improved, and an anion having a high molecular weight can be used. The charge per unit area of the anion is reduced, and the force pulled by the cation is reduced. As a result, the anion is uniformly dispersed. As a result, the resistance value of the roller surface can be set to a desired value, and the developing roller And the frictional charge between the toner and the toner can be suppressed.

Accordingly, the present invention provides the following conductive roller.
[1] A conductive roller having a base layer and a surface layer on an outer peripheral surface of a shaft, wherein the surface layer is formed using a resin as a main material, and a main chain or a terminal portion of the resin is A conductive roller, which is chemically bonded to a heterocyclic aromatic group having an amidinium group.
[2] The conductive roller according to [1], wherein the heterocyclic aromatic group is an imidazolium ring.
[3] The conductive roller according to [1] or [2], wherein the chemical bond between the main chain or terminal portion of the resin and the heterocyclic aromatic group having an amidinium group is a urethane bond.
[4] The conductive roller according to any one of [1] to [3], wherein the reactive functional group of the heterocyclic aromatic group having an amidinium group is a hydroxyl group.
[5] The conductive roller according to any one of [1] to [4], wherein the resin material of the surface layer contains an electrolyte anion having a molecular weight of 200 or more.
[6] The conductive roller according to [5], wherein the electrolyte anion is a sulfonimide ion.
[7] The conductive roller according to any one of [1] to [6], which is used as a developing roller.

  According to the conductive roller of the present invention, the resistance value of the roller surface can be set to a desired value, and the frictional charging between the developing roller and the toner can be suppressed, which effectively prevents the occurrence of image defects. Therefore, a good image can be reliably obtained.

It is a schematic sectional drawing which shows an example of the electroconductive roller (developing roller) of this invention. It is a schematic sectional drawing which shows an example of the image development apparatus using the said developing roller.

Hereinafter, the present invention will be described in more detail.
As described above, the conductive roller of the present invention has a base layer and a surface layer on the outer peripheral surface of the shaft. For example, as shown in FIG. 1, a conductive roller 1 that forms a base layer (elastic layer) 3 and a surface layer 4 on the outer peripheral surface of a shaft 2. The conductive roller of the present invention can form a single layer or a plurality of intermediate layers according to the purpose between the base layer 3 and the surface layer 4 according to the purpose of use. The layers can be formed not only in one layer but also in two or more layers.

  As the shaft (core metal) 2, any one can be used as long as it has good conductivity. Usually, a metal core made of a solid metal such as iron, stainless steel, or aluminum is used. A metal shaft such as a metal cylinder hollowed inside is used.

  Next, the base layer 3 formed on the outer periphery of the shaft 2 is usually an elastic layer. This base layer (elastic layer) is formed of an elastic body obtained by blending an elastomer alone or a foam body obtained by foaming it with an electronic conductive agent such as carbon black or an ionic conductive agent such as sodium perchlorate. The

  Examples of the elastomer include silicone rubber, urethane rubber, polybutadiene rubber, polyisoprene rubber, natural rubber, styrene butadiene rubber, nitrile rubber, ethylene propylene rubber, acrylic rubber, epichlorohydrin rubber, chloroprene rubber, and mixtures thereof. It is done. Further, these elastomers can be used as a foam body that is foamed chemically by a foaming agent or foamed by mechanically entraining air like a polyurethane foam.

  As the base layer 3, it is preferable to use a polyurethane foam obtained by mechanical stirring foaming from a polyurethane raw material containing a polyol component and an isocyanate component. This polyurethane foam will be described below.

  In this case, the polyol component is not particularly limited, and any known polyol as a raw material polyol for producing urethane foam can be used. For example, a polyether polyol, a polyester polyol, or a polyester polyether polyol can be used for a roller. Although it can select suitably according to it, especially polyester polyol and polyether polyol are used preferably, and any one or both of these can be mixed and used.

  More specifically, as polyether polyol, polyether polyol obtained by addition polymerization of alkylene oxide such as polyethylene oxide or propylene oxide to glycerin, etc., polyether polyol obtained by ring-opening polymerization of tetrahydrofuran, Examples thereof include polyether polyols such as polytetramethylene glycol, ethylene glycol, propanediol, and butanediol.

  Polyester polyols include condensation polyester polyols obtained by condensation of dicarboxylic acids with diols, triols, etc., lactone polyester polyols obtained by ring-opening polymerization of lactones based on diols and triols, and ends of polyether polyols. A polyol such as an ester-modified polyol obtained by ester-modifying lactone with lactone is exemplified.

  These polyols are not particularly limited, but preferably have a number average molecular weight of 360 to 5,600, particularly preferably 400 to 1,000, and a hydroxyl value of 30 to 390 mgKOH, particularly preferably 180 to 390 mgKOH. The number of functional groups is preferably 2.5 to 3, and the polyether polyol preferably has an ethylene oxide content of 1 to 10%.

  Next, the isocyanate is not particularly limited, and can be appropriately selected from conventionally known various isocyanate compounds. Specifically, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), modified TDI, modified MDI, modified HDI, etc. are exemplified, and in particular, modified TDI, modified MDI, and modified HDI are preferably used. It is done. In this case, the type of the modified product is not particularly limited, but a polyol-modified product is preferable. Among them, a polyol-modified TDI is particularly preferably used in combination with the polyether polyol or polyester polyol. These isocyanates are not particularly limited, but the NCO content is preferably 1 to 25%, particularly 4 to 10%.

  Usually, this polyurethane foam is blended with a conductive agent to impart or adjust conductivity. As the conductive agent, a known ionic conductive agent or electronic conductive agent can be used, and further, an ionic conductive agent and an electronic conductive agent can be used in combination.

  Examples of the ion conductive agent include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (for example, lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (for example, stearyltrimethylammonium), benzyltrimethylammonium, and a modified fatty acid dimethylethylammonium. Perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, ethyl sulfate, carboxylate, sulfonate, etc. ammonium salt, lithium, sodium Perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides, trifluoromethyls of alkali metals and alkaline earth metals such as potassium, calcium and magnesium Sulfates, such as sulfonate are exemplified.

  In addition, as the electronic conductive agent, conductive carbon such as ketjen black and acetylene black; rubber carbon such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT; carbon for ink subjected to oxidation treatment, Examples include pyrolytic carbon, natural graphite, and artificial graphite; conductive metal oxides such as tin oxide, titanium oxide, and zinc oxide; metals such as nickel, copper, silver, and germanium.

  Furthermore, in addition to the polyol component, isocyanate component and conductive agent, an appropriate amount of known additives such as a foam stabilizer, a crosslinking agent, a surfactant, and a catalyst are added to the polyurethane foam as necessary. Can do.

  Examples of the foam stabilizer include polydimethylsiloxane-polyethylene oxide copolymer, polydimethylsiloxane-polypropylene oxide copolymer, polydimethylsiloxane-polyethylene adipate copolymer, and the like.

  Examples of the catalyst include dibutyltin dilaurate, dibutyltin diacetate, stannous octoate, dibutyltin marker peptide, dibutyltin thiocarboxylate, dibutyltin dimalenite, dioctyltin marker peptide, dioctyltin thiocarboxylate as organometallic catalysts. , Phenylmercury, silver propionate, tin octenoate, amine catalyst triethylamine, N, N, N ′, N′-tetramethylethylenediamine, triethylenediamine, N-methylmorpholine, dimethylaminoethanol, bis (2-dimethylaminoethyl) ) Ether, 1,8-diazabicyclo (5,4,0) -undecene-7 and the like are preferably used. These catalysts may be used alone or in combination of two or more.

  When the polyurethane foam is used as a base layer, a mold in which the isocyanate component, polyol component, conductive agent, and the additive added as necessary are mixed, foamed mechanically, and set with a shaft (core metal). It can be obtained by being cast inside and thermally cured to form a base layer made of polyurethane foam around the shaft.

  As the base layer 3, a UV curable resin material can be suitably used. For example, it is possible to use the UV curable resin material described in JP2012-159736A.

  As the UV curable resin material, for example, (A) urethane (meth) acrylate oligomer, (B) (meth) acrylate monomer, (C) ion conductive agent, and (D) photopolymerization initiator are irradiated with UV light. It can be obtained by irradiation.

  The polyol used for the synthesis of the (A) urethane (meth) acrylate oligomer preferably has a molecular weight in the range of 500 to 15,000. If the molecular weight of the polyol used for the synthesis of the urethane prepolymer is less than 500, the hardness becomes high, so that it becomes unsuitable for the layer of the developing roller. On the other hand, if it exceeds 15,000, the compressive residual strain increases, resulting in poor image quality. It tends to occur.

  About the said (D) photoinitiator and its compounding quantity, it can select suitably in the range of the kind and compounding quantity similar to what was described in Unexamined-Japanese-Patent No. 2012-159736.

  The (C) ionic conductive agent has a function of imparting conductivity to the elastic layer. In addition to being dissolved in the (A) urethane (meth) acrylate oligomer, the ionic conductive agent has transparency, so even if the elastic layer forming composition is applied thickly on the shaft, the ultraviolet rays are sufficiently inside the coating film. And the elastic layer forming composition can be sufficiently cured. Examples of such ionic conductive agents include perchlorates such as tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, modified fatty acid dimethylethylammonium, chlorate, hydrochloride, Ammonium salts such as bromate, iodate, borofluoride, sulfate, ethyl sulfate, carboxylate, sulfonate; alkali metals such as lithium, sodium, potassium, calcium, magnesium, alkaline earth Examples include metal perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides, sulfates, trifluoromethyl sulfates, sulfonates, and the like.

  Among them, as an ionic conductive agent suitable in the present invention, for example, sodium perchlorate (MP-100, manufactured by Showa Chemical Industry Co., Ltd.), an acrylic monomer solution of lithium imide (Sanconol MTGA-50R, Sanko Chemical Industry ( And the like). These electrically conductive agents may be used individually by 1 type, and may use 2 or more types together. Although the compounding quantity of the ionic conductive agent in the composition for forming an elastic layer depends on the type, the (A) urethane (meth) acrylate oligomer and (B) (meth) acrylate monomer constituting the UV curable resin material are included. A range of 0.1 to 5.0 parts by mass, particularly 0.4 to 2.0 parts by mass, and further 0.4 to 1.2 parts by mass is preferable with respect to 100 parts by mass in total.

  In addition to the above, various known additives can be added to the resin material forming the elastic layer as long as the desired effects of the present invention are not impaired.

  The thickness of the base layer made of the polyurethane foam or UV curable resin material is appropriately set depending on the use of the conductive roller or the design of the electrophotographic apparatus on which the roller is set, and is not particularly limited. Usually, it is preferably 0.5 to 10 mm, particularly 3 to 6 mm.

  Next, in the conductive roller of the present invention, a surface layer is formed directly on the base layer (elastic layer) or through various intermediate layers. The surface layer is preferably a resin coating layer, and the resin coating layer can be formed as a main material using a known resin selected according to the application of the roller, for example. , Urethane resin, acrylic resin, acrylic urethane resin, fluororesin, silicone resin and the like. A particularly preferred embodiment is to use a urethane resin, an acrylic resin, or an acrylic urethane resin.

  In the present invention, the surface layer is characterized in that the main chain or terminal portion of a resin used as a main material is chemically bonded to a heterocyclic aromatic group having an amidinium group. Thus, by using the resin having a chemical bond with the heterocyclic aromatic group, the resistance value of the roller surface can be set to a desired value and the frictional charging between the developing roller and the toner can be suppressed. The object and effect of the invention can be sufficiently achieved.

  Specifically, as the “heterocyclic aromatic group having an amidinium group”, a 5-membered cyclic group having an amidinium group such as an imidazole ring (imidazolium ring) or an imidazoline ring is preferably used. A group having an imidazole ring which is a nitrogen-containing aromatic heterocyclic compound containing a nitrogen atom at the 1,3-position on the ring is preferred.

In order to obtain a group having an imidazole ring in the resin of the surface layer, the following method (1) or (2) may be mentioned.
(1) It can be synthesized by reacting a glyoxal derivative with ammonia and formaldehyde.
(2) By using an imidazole group-containing compound synthesized by the method (1) as a raw material, imidazole and imidazole having a more complicated substituent can be synthesized by an addition reaction, a substitution reaction, or the like.

  In addition, when using the imidazolium salt which is a salt comprised from the cation which has an imidazole ring, the commercially available ionic liquid can be used, Specifically, Tokyo Chemical Industry Co., Ltd. 1-butyl-3- Methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methyl Imidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-butyl-2,3-dimethylimidazolium chloride, 1-butyl-2,3-dimethylimidazolium tetrafluoro Borate, 1-butyl-2,3-di Chill hexafluorophosphate, 1-butyl-2,3-dimethyl-imidazolium bis (trifluoromethanesulfonyl) imide, and the like.

  Moreover, when the resin of the surface layer is a urethane resin, a method such as copolymerization with an imidazolium compound containing a hydroxyl group in a urethane prepolymer or oligomer prepared in advance by a prepolymer method is employed. By this, it is possible to obtain a urethane resin to which a group having an imidazole ring is bonded. For example, when a bifunctional isocyanate compound and a bifunctional diol compound are reacted, an imidazolium compound containing a hydroxyl group is mixed with a part of the diol, and the number of moles of each isocyanate group (NCO) and the mole of hydroxyl group (OH). By designing the number, it is possible to synthesize a urethane resin in which the content and physical properties of the imidazolium group are controlled.

  The resin material for the surface layer can contain an electrolyte anion and preferably has a molecular weight of 200 or more, specifically, bis (trifluoromethanesulfonyl) imide ion, bis (nonafluorobutanesulfonyl). It is preferable to use imide or the like.

  In addition, when the surface layer contains an electronic conductive agent, the amount of the electronic conductive agent added is 0 to 20% by mass with respect to the amount of the electrolyte cation and the electrolyte anion. Is preferred.

  In this resin coating layer, an appropriate additive can be blended depending on the use of the roller, for example, the same conductive agent or resin curing agent as exemplified in the elastic layer, if necessary. An appropriate amount can be added.

  The thickness of the resin coating layer is appropriately set according to the type of resin constituting the resin layer, the use of the roller, the characteristics of the elastic layer, and the like, and is not particularly limited, but is usually 1 to 20 μm. In particular, the thickness is preferably 5 to 10 μm. Moreover, this resin coating film layer may be a single layer or may be formed by laminating a plurality of layers, and can usually be 1 to 5 layers.

  The resin coating layer is formed by dissolving and dispersing the above resin components and additives in a solvent such as methyl ethyl ketone, methyl isobutyl ketone, toluene, ethyl acetate, and methylcyclohexane to prepare a resin coating, dipping and spraying the resin coating The coating may be performed on the elastic layer by a known method such as a roll coater.

  Note that, as described above, the conductive roller of the present invention forms a single layer or a plurality of intermediate layers between the base layer 3 and the surface layer 4 depending on the purpose of use. For example, the resistance adjustment layer and various resin coating layers can be formed in one or more layers.

  The conductive roller of the present invention is not particularly limited, but can be applied to a developing roller, a toner supply roller and the like used in an electrophotographic apparatus, and particularly preferably provided to the developing roller. The developing roller is usually disposed in contact with or close to the surface of a latent image holding body such as a photosensitive drum holding an electrostatic latent image, and rotates to bring developer carried on the surface onto the surface of the latent image holding body. And the electrostatic latent image held on the surface of the latent image holding body is visualized. Specifically, as shown in FIG. 2, the developing roller 1 shown in FIG. 1 is used as the developing roller 1 between the toner supply roller 5 for supplying toner and the photosensitive drum 6 holding the electrostatic latent image. The roller is disposed in contact with or close to the photosensitive drum 6, the toner 7 is supplied to the developing roller 1 by the toner supply roller 5, and this is carried on the surface of the developing roller 1 and uniformly formed by the stratified blade 8. A thin layer is prepared, and toner is supplied to the photosensitive drum 6 from the thin layer, and the latent image is visualized by attaching the toner to the electrostatic latent image on the surface of the photosensitive drum. In the figure, reference numeral 9 denotes a transfer part, reference numeral 10 denotes a cleaning part, and reference numeral 11 denotes a cleaning blade.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Examples 1-6, Comparative Examples 1-6]
[ Preparation method of base layer / thermosetting urethane A ]
50 parts by mass of polyether polyol (“Sanix FA-951” manufactured by Sanyo Kasei Kogyo Co., Ltd.), 25 parts by mass of polyester polyol (“Kuraray Polyol F-510” manufactured by Kuraray Co., Ltd.), polyester polyol (“Kuraray Polyol Co., Ltd. manufactured by Kuraray Co., Ltd.) F-1010 "), 23 parts by mass of dibutyltin dilaurate (" Neostan U-100 "manufactured by Nitto Kasei Co., Ltd.), and a foam stabilizer for urethane foam (" SF "manufactured by Toray Dow Corning Silicone) -2937F "is weighed. The polyol mixture is set as a liquid A in a mechanical floss injection tank. 200 parts by mass of prepolymerized TDI (NCO% = 7%) and acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.) Denka Black ") 4 parts by weight are weighed and stirred into a container. Is set in a mechanical floss injection tank as liquid B. The flow rate is adjusted so that the INDEX ratio (number of moles of NCO / number of moles of OH) = 1.1, and the mixture is poured into the mold in an oven at 120 ° C. for 30 minutes. Heat and remove the cured urethane base layer from the mold.

In addition, the preparation methods of said prepolymerized TDI are as follows.
<Prepolymerized TDI preparation method>
Trifunctional polypropylene glycol (“Exenol 5030” manufactured by Asahi Glass Co., Ltd.) and tolylene diisocyanate (TDI) are accurately weighed in a three-necked flask so as to be INDEX4.5. Using a mantle heater, the mixture is heated at a liquid temperature of 70 ° C. for 2 hours. By the hydroxyl value method, the disappearance of the polyol is confirmed and the reaction is completed.

[ Production method of UV base layer / UV cured urethane B ]
800 parts by mass of urethane acrylate oligomer, hydroxyl group-containing (meth) acrylate described in the examples, photopolymerization initiator ("IRGACURE 184" manufactured by Ciba Specialty Chemicals Co., Ltd.), ionic conductive agent (lithium salt / polyol) (Sanko Chemical Industries) 5 parts by mass of “Sanconol PEO20R” manufactured by the company are each weighed and agitated, and the above-mentioned base material is coated with a thickness of 0.5 mm by die coating, and irradiated with UV by an H bulb of a UV lamp manufactured by FusionUV (irradiation conditions: 1,500 mJ / cm ² ) to cure the coating film.

[ Production method of surface layer ]
Urethane acrylate oligomer C listed in Table 1, spherical urethane resin particles (“Art Pearl C800” manufactured by Negami Kogyo Co., Ltd.), photopolymerization initiator (“IRGACURE 184” manufactured by Ciba Specialty Chemicals Co., Ltd.) were weighed, and methoxypropyl acetate was added. Adjust to a solid content of 30% by mass and stir.Apply surface coating to the base material prepared by the above method by roll coating method.Use UV light of UV lamp manufactured by FusionUV (irradiation) Condition: irradiation condition: 1,500 mJ / cm ² ), and the coating film is cured.

The production method of the urethane acrylate oligomer C is as follows.
<Method for producing urethane acrylate oligomer>
Polyester polyol (“Kuraray polyol P2010” manufactured by Kuraray Co., Ltd.) and isophorone diisocyanate (IPDI) are accurately weighed in a three-necked flask so that INDEX is 1.55. Next, 0.01 mass% dibutyltin laurate is added with respect to the total amount (mass part) of a polyol and isocyanate, stirring this mixture at 100 rpm. This mixture is heated with a mantle heater at a liquid temperature of 70 ° C. for 2 hours. Thereafter, the disappearance of the polyol is confirmed by a hydroxyl value method. 2-Hydroxyethyl acrylate (HEA) is accurately weighed, dropped into a three-necked flask, and heated with a mantle heater at a liquid temperature of 70 ° C. for 2 hours. The disappearance of the isocyanate is confirmed by infrared spectroscopic analysis (IR) using an infrared spectrophotometer (Nicolet iS5 FT-IR spectrometer), and the reaction is completed.

  The following evaluation was performed about the test sample (laminated body) which has said base layer and surface layer.

[Acetone extraction rate]
Weigh the empty eggplant flask using a precision balance that can measure up to 0.1 mg (assumed to be Ag). Cut the resin to be extracted into about 1 cm square. About 3 to 5 g of resin to be extracted is put on a Soxhlet filter paper, and the weight is accurately measured with a precision balance (referred to as Bg). Add 150 ml of acetone to the eggplant flask. Put Soxhlet filter paper into Soxhlet extraction tube. A Dimroth condenser is installed on the Soxhlet extraction tube, the eggplant flask is heated, and acetone is heated to reflux for 5 hours. Remove the eggplant flask and remove the acetone with a rotary evaporator. The eggplant flask is dried in an oven at 80 ° C. for 4 hours. Check that the oven is cold and measure the weight of the eggplant flask (Cg).
The formula “(C−A) ÷ B × 100 (%)” is defined as the acetone extraction rate.

[Resistance value of surface layer and roller]
The resistance values of the surface layer and the roller were measured under conditions of a temperature of 10 ° C. and a humidity of 15% RH (LL), or a temperature of 23 ° C. and a humidity of 55% RH (NN).

[Roller toner charge]
Using a commercially available monochrome laser printer (HL-L2360DN), the charge amount of the toner was measured using a digital electrometer 8252 (manufactured by ADMT Corporation). The notations (NN) and (LL) in the table are the same as above.

[Determination of image defects]
Using a commercially available monochrome laser printer (HL-L2360DN), 25% when printing 3000 sheets with monochrome image quality (printing at 1% density) in an environment of temperature 10 ° C. and humidity 15% RH (LL), 35% % Halftone was printed on each of cyan, magenta, yellow, and black, and the image quality was visually evaluated. Regarding image quality, it was observed that toner was scattered in the white part of the halftone when enlarged with a microscope. This is presumably because the toner development cannot be controlled due to the excessive charge amount. Problems with the image are “toner is scattered all over the white part (Lv.5)”, “scattering up to 50 points in 500 × field of view (Lv.4)”, “scattering up to 10 points in 500 × field of view ( Lv.3) ”, scattering up to 3 points at 500 × field of view (Lv.2)” and “no problem at all (Lv.1)” were determined according to the following criteria.

  The detail of each raw material of said surface layer is as follows.

"Imidazolium salt-modified urethane acrylate oligomer D"
A Dimroth condenser and a stirring blade are placed in a nitrogen-substituted 3 L three-necked flask, and 500 ml of butyl acetate, 407 g of 1- (2-hydroxyethyl) -3-methylimidazolium bis (trifluoromethanesulfonyl) imide, and 222 g of isophorone diisocyanate are weighed. Stir well. 0.05 g of dioctyltin dilaurate is weighed into a microsyringe and dropped into a stirring three-necked flask. After 2 hours of reaction at 60 ° C. in an oil bath, 5 ml of the reaction solution is taken out and NCO% is measured by the method defined in JIS K1603-1. After confirming that the NCO group has reacted 50%, 116 g of hydroxyethyl acrylate is dropped into the three-necked flask. After suitable conditions for hydroxyethyl acrylate, continue the reaction in an oil bath at a liquid temperature of 60 ° C. for 2 hours, and measure the reaction liquid with an infrared spectrophotometer (Nicolet iS5 FT-IR spectrometer). Confirm the reaction to complete the reaction. The obtained butyl acetate solution was used as an imidazolium salt-modified urethane acrylate oligomer D.

"Imidazolium salt-modified urethane acrylate oligomer E"
The isophorone diisocyanate was changed to 174 g of toluene diisocyanate to carry out the reaction, and the resulting butyl acetate solution was used as an imidazolium salt-modified urethane acrylate oligomer E.

"Imidazolium salt-modified urethane acrylate oligomer F"
The reaction was carried out by changing the isophorone diisocyanate to 168 g of hexamethylene diisocyanate, and the resulting butyl acetate solution was used as the imidazolium salt-modified urethane acrylate oligomer F.

-Imidazolium salt "IL-IM1" ... Ionic liquid manufactured by Guangei Chemical Industry Co., Ltd.-Imidazolium salt "IL-210"-... Daiichi Kogyo Seiyaku Co., Ltd., 1-ethyl-3 -Methylimidazolium bis (trifluoromethylsulfonyl) imide

  From the results of Table 1, in Examples 1 to 6, by using the imidazolium salt-modified urethane acrylate oligomer, it is possible to keep the roller resistance value and the toner charge amount low while keeping the acetone extraction rate low. I understand. In Comparative Examples 2, 3, 5, and 6, the resistance value and the toner charge amount can be suppressed by adding an imidazolium salt having no reactive group (acrylate), but the acetone extraction rate is increased. I understand that. As the acetone extraction rate increases, chemical attack on the toner occurs, and image defects occur when left in an environment of 40 ° C. or higher for 12 hours or longer.

[Examples 7 to 14, Comparative Examples 7 to 10]
Next, examples of Examples 7 to 14 and Comparative Examples 7 to 10 are shown. In this example, the base layer (thermosetting urethane A and UV curable urethane B) is formed with the surface layer shown in Table 2 below.
[The following surface layer production method]
Weigh the polyols listed in Table 2, spherical urethane resin particles ("Art Pearl C800" manufactured by Negami Kogyo Co., Ltd.), and HDI urethane curing agents ("Daipura Coat EN2" manufactured by Dainichi Seika Kogyo Co., Ltd.), and use methyl ethyl ketone (MEK). In addition, adjust and agitate to a solid content of 3% by mass. The base material produced by the above method is applied to the surface coating material by dipping and heated in an oven at 120 ° C. for 60 minutes.

・ "OH-containing imidazolium salt G"
1- (2-Hydroxyethyl) -3-methylimidazolium bis (trifluoromethanesulfonyl) imide “KS48”... Hydroxyl group-containing ammonium salt manufactured by Kao Corporation

  From the results of Table 2, it can be seen that in Examples 7 to 11, by using the hydroxyl group-containing imidazolium salt, it is possible to keep the roller resistance value and the toner charge amount low while keeping the acetone extraction rate low. In Comparative Examples 8 and 9, although the resistance value and the toner charge amount can be suppressed by adding an imidazolium salt having no reactive group (OH group), the acetone extraction rate increases. It can be seen that chemical attack on the toner occurs due to an increase in the acetone extraction rate, and image defects occur when left in an environment of 40 ° C. or more for 12 hours or more.

[Examples 15 to 18, Comparative Examples 10 to 12]
Next, examples of Examples 15 to 18 and Comparative Examples 10 to 12 are shown. In this example, the base layer (thermosetting urethane A and UV curable urethane B) has the same configuration as the surface layer shown in Table 2 above.

  From the results of Table 3 above, it is understood that in Examples 15 to 18, the roller resistance value and the toner charge amount can be kept low while the acetone extraction rate is suppressed by using the hydroxyl group-containing imidazolium salt. . In contrast, in Comparative Examples 11 and 12, the resistance value and the toner charge amount can be suppressed by adding an imidazolium salt having no reactive group (OH group), but the acetone extraction rate is increased. I understand that. As the acetone extraction rate increases, chemical attack on the toner occurs, and image defects occur when left in an environment of 40 ° C. or higher for 12 hours or longer.

1 Conductive roller (developing roller)
2 Shaft 3 Base layer (elastic layer)
4 Surface layer (resin coating layer)

Claims (7)

  A conductive roller having a base layer and a surface layer on an outer peripheral surface of a shaft, wherein the surface layer is formed using a resin as a main material, and a main chain or a terminal portion of the resin has an amidinium group. A conductive roller, which is chemically bonded to a heterocyclic aromatic group.   The conductive roller according to claim 1, wherein the heterocyclic aromatic group is an imidazolium ring.   The conductive roller according to claim 1 or 2, wherein a chemical bond between the main chain or terminal portion of the resin and a heterocyclic aromatic group having an amidinium group is a urethane bond.   The conductive roller according to claim 1, wherein the reactive functional group of the heterocyclic aromatic group having the amidinium group is a hydroxyl group.   The conductive roller according to claim 1, wherein the resin material of the surface layer contains an electrolyte anion having a molecular weight of 200 or more.   The conductive roller according to claim 5, wherein the electrolyte anion is a sulfonimide ion.   The conductive roller according to claim 1, wherein the conductive roller is used as a developing roller.

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