JP2007011059A - Semiconductive elastic member for electrophotography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductive elastic member by which a member to be contacted, for example, a photoreceptor or the like used in an electrophotographic device is restrained from being soiled. <P>SOLUTION: A semiconductive elastic body layer is formed by hardening (a) organically modified layered clay mineral and (b) material of the semiconductive elastic body layer raw material containing oligomer having an epoxy group. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductive elastic member for electrophotography, such as a developing member, a charging member, and a transfer member, used in an electrophotographic apparatus.

  In an image forming apparatus such as an electrophotographic apparatus such as a copying machine or an optical printer or an electrostatic recording apparatus, a corona discharge has been conventionally used as a means for charging an image carrier such as a photosensitive member or a dielectric.

  However, although corona discharge is effective as a means for uniformly charging the surface of the image carrier to be charged at a predetermined potential, it requires an expensive high-voltage power source and the apparatus becomes large, and ozone in corona discharge In some cases, problems such as generation and destruction of the charged surface due to abnormal discharge may occur.

  In contrast to such a corona discharge method, a contact charging method has been adopted in recent years. In the contact charging method, a charged member (charging member) to which a voltage is applied is brought close to or in contact with the surface to be charged to charge the surface to be charged. Compared with the corona discharge method, corona products such as ozone are charged. There are advantages such as less generation, simple structure, low cost, miniaturization of the apparatus, and less damage to the charged surface due to abnormal discharge. Usually, a semiconductive roller having a semiconductive elastic layer formed on a metal core is used.

The elastic elastic layer of the charging member used in the contact charging method needs to have an appropriate semiconductivity in order to prevent leakage caused by pinholes, scratches, etc. on the surface to be charged such as a photoconductor. In addition, in order to uniformly charge the surface to be charged, the elastic layer of the charging member has uniform conductivity in a semiconductive region having a volume resistivity of about 1 × 10 ³ to 1 × 10 ⁹ Ω · cm. It is important to have. And in order to implement | achieve such electroconductivity, the elastic body layer is conventionally produced using the electroconductive rubber composition which mix | blended electroconductive particles, such as electroconductive carbon black, and was semiconductive. .

However, although such an electronic conductive rubber composition can adjust the electric resistance depending on the amount of conductive particles added to the raw rubber, the volume resistivity is 1 × 10 ³ to 1 × 10 ⁹ Ω · In the semiconductive region of cm, depending on the type of conductive particles, the electrical resistance may change greatly due to a slight change in the blending amount of the conductive particles. Therefore, it is difficult to produce an elastic body layer having a uniform desired electric resistance value in the semiconductive region, and the electric resistance tends to vary within the charging member and between the charging members.

  As a method of obtaining a rubber molded product having a uniform electric resistance, it is possible to use a semi-conductive polar rubber such as epichlorohydrin rubber or NBR, or to add semi-conductive by adding an ionic conductive agent to the raw rubber. It is known that an elastic body layer is composed of an imparted ion conductive rubber.

  On the other hand, the charging member is also required not to contaminate an image carrier such as a photoreceptor (hereinafter referred to as “photoreceptor”). In the contact charging method, since the charging member is used in contact with the photoreceptor, low molecular weight components such as an ionic conductive agent and a softening agent in the charging member contaminate the photoreceptor during long-term use. It may cause functional failure and image defects may occur. As a method for preventing photoreceptor contamination due to low molecular weight components, there is an example in which a layered organic silicate is mixed in a rubber material used for a charging member (see, for example, Patent Document 1).

However, in recent years, with high image quality and high speed in an electrophotographic apparatus, there is a demand for a charging member that is low in electrical resistance but less contaminated with a photoreceptor. The polar rubber used as the raw material polymer for the charging member is an ionic conductive agent that is used for the purpose of lowering the electric resistance, as the lower the electric resistance, the faster the migration speed of the low molecular weight component in the charging member, However, it is likely to cause photoconductor contamination.
Japanese Patent Laid-Open No. 2003-223038

  An object of the present invention is to provide a semiconductive elastic member used in an electrophotographic apparatus in which contamination to a contacted member such as a photoreceptor is suppressed.

  As a result of intensive studies on the above problems, the present inventors have formulated a semi-conductive elastic body layer by blending an organically modified layered clay mineral and a low molecular weight polymer (oligomer) having an epoxy group into the raw material. The inventors have found that an electrophotographic semiconductive elastic member with very little contamination to the photoreceptor can be provided, and have further studied to arrive at the present invention.

  That is, the present invention has the following configuration.

(1) The electroconductive elastic layer is formed by curing from a semiconductive elastic layer material containing (a) an organically modified layered clay mineral and (b) an oligomer having an epoxy group. Semiconductive elastic member.

(2) The electroconductive semiconductive elastic member for electrophotography according to (1), wherein the oligomer having an epoxy group is an epoxidized butadiene oligomer.

(3) The electroconductive semiconductive elastic member for electrophotography according to the above (1) to (2), wherein the layered clay mineral is bentonite.

(4) The above-mentioned (1) to (3), wherein an interlayer distance based on a layered clay mineral is observed at 3.7 nm to 5.0 nm by measuring the semiconductive elastic body layer by X-ray diffraction Semiconductive elastic member for electrophotography.

  ADVANTAGE OF THE INVENTION According to this invention, it became possible to provide the semiconductive elastic member used for the electrophotographic apparatus by which the contamination to the to-be-contacted member, for example, a photoreceptor, was suppressed.

  Hereinafter, embodiments of the present invention will be described in more detail.

  The semiconductive elastic member according to the present invention is a rubber elastic body molded body that is mainly used in contact with a photoreceptor of an electrophotographic apparatus and has conductivity of at least a semiconductor region. (A) Organically modified layered clay It is formed by curing from a semiconductive elastic layer material containing a mineral and (b) an oligomer having an epoxy group.

  Specifically, in a roll-shaped semiconductor elastic member, (a) an organically modified layered clay mineral (hereinafter referred to as an organically modified layered clay mineral, A semiconductive elastic layer material containing (a) component) and (b) an oligomer having an epoxy group (hereinafter also referred to as (b) component) is molded, cured, and semiconductive The elastic elastic body layer is formed.

  The (a) organically modified layered clay mineral used in the present invention is one in which an organic substance is modified between layers of a layered clay mineral. The organic matter may be physically adsorbed between the clay mineral layers or chemically bonded.

  The layered clay mineral is formed by laminating a plate-like silicate layer having a thickness of about 1 nm, for example, smectite or vermiculite such as montmorillonite, beidellite, nontronite, sabonite, hectorite, and saconite. The surface of the silicate layer is negatively charged, and inorganic cations such as potassium, sodium, lithium and calcium are usually interposed between the layers to keep them electrically neutral. Are easily replaceable. Further, it is known that the interlayer easily swells with water due to the nature of the inorganic cation.

  In the present invention, as the organically modified layered clay mineral, the inorganic cation between the above layered clay minerals is, for example, trimethyl stearyl ammonium ion, dimethyl stearyl ammonium ion, dimethyl dioctadecyl ammonium ion, oleyl bis (2-hydroxyethyl). An organic cation represented by a quaternary ammonium ion such as methylammonium ion, which is partially or completely ion-exchanged and replaced between layers can be used.

  Although the usage-amount of an organic modified layered clay mineral is not specifically limited, 0.5-100 mass parts is preferable with respect to 100 mass parts of rubber components of an elastic body raw material. When the amount of the organically modified clay mineral used is less than 0.5 parts by mass, the effect of preventing the contamination of the semiconductive member cannot be sufficiently obtained, and when it exceeds 100 parts by mass, the hardness of the semiconductive elastic member is very high. It is not preferable. A more preferable range is 1 to 30 parts by mass.

  The oligomer (b) having an epoxy group used in the present invention has an unsaturated bond such as oligobutadiene, oligoisoprene, oligoacrylonitrile-butadiene copolymer, oligostyrene-butadiene in the molecule, and has a number average molecular weight of 1000. Is a compound in which at least one of the unsaturated bonds is an epoxy group, and the epoxy group is present at the terminal, side chain or main chain, preferably at the terminal and / or side chain of the oligomer molecule. In addition, as epoxy group content, it is preferable that it is 100-10000 in an epoxy equivalent. Furthermore, a functional group such as a hydroxyl group, a carboxyl group, and an amino group other than an epoxy group may be modified at the terminal or / and the side chain.

  The amount of the oligomer having an epoxy group is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the elastic layer raw material polymer. If it is smaller than this value, the effect of preventing contamination cannot be sufficiently obtained, and the decrease in viscosity that leads to improvement in workability is also small. When it is larger than this value, the physical properties such as compression set of the semiconductive elastic body are lowered.

  The oligomer having an epoxy group reacts with at least one of the oligomer having an epoxy group, the organically modified layered clay mineral, the elastic layer material polymer, various compounding agents, etc. in the semiconductive elastic layer, and Achieve the effect.

  Further, the oligomer having an epoxy group reacts and crosslinks by heat treatment at the time of processing the member, so that the oligomer having the epoxy group itself does not migrate to the surface and does not contaminate the photoreceptor.

  Regarding the action mechanism of the antifouling effect of the present invention, the organically modified layered clay mineral is further expanded by the coexistence with the oligomer having an epoxy group, in addition to the layer being expanded compared to the organically modified layered clay mineral. Spread. An oligomer having an epoxy group has a polarity, so that it easily penetrates between layers of an organically modified layered clay mineral and functions to expand the layer. Compared to the case of not using oligomers that have a high molecular weight, it is considered that even relatively large molecular weight contaminants can be physically and chemically adsorbed and retained between the layers, preventing migration from elastic bodies to the outside. . As another mechanism of action, the presence of an oligomer having an epoxy group makes it easy for the raw material polymer used for the elastic body to enter between the layers, physically and chemically adsorbing, and heating and curing the nanocomposite. It is considered that the molecular movement of the elastic layer-constituting polymer is restricted and the migration rate of the contaminant in the elastic body is reduced, thereby preventing contamination.

  In particular, when organically modified layered clay mineral, bentonite, which is a natural mineral mainly composed of montmorillonite, is modified with organic ammonium, epoxidized butadiene oligomer is used as an oligomer having an epoxy group. The prevention effect is great.

  The raw material polymer for the elastic body is not particularly limited, but it is preferable to use an ion conductive polymer having uniform electric resistance. Examples of the ion conductive polymer include epichlorohydrin homopolymer (CO), epichlorohydrin-ethylene oxide copolymer (ECO), epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer (GECO), acrylonitrile-butadiene copolymer ( NBR), hydrogenated acrylonitrile-butadiene copolymer (NBR), acrylic rubber (ACM, ANM), urethane rubber (AU, EU) and the like. In addition, a raw material polymer is not restricted to these, Moreover, 1 type may be used or 2 or more types may be used together. At this time, an ion conductive polymer having a lower electric resistance is desired in order to improve the charging ability as the electrophotographic apparatus is increased in speed. Generally, the lower the resistance of the starting polymer, the worse the contamination. However, by using the present invention, it is possible to prevent contamination of the photoreceptor even when such a low-resistance raw material polymer is used.

The volume resistivity of the elastic layer is preferably 1 × 10 ³ to 1 × 10 ⁹ Ω · cm so that a charging voltage can be applied to the electrophotographic photosensitive member. Therefore, conductive particles such as oxides such as carbon black, graphite, and titanium oxide, and metals such as copper and silver may be added to the elastic layer in order to adjust electric resistance.

  The interlayer distance of the organically modified layered clay mineral is determined by performing a 2θ / θ scan on the polymer composition sample containing the mineral using an X-ray diffractometer and calculating the lattice spacing calculated from the peak angle of the diffraction intensity. Defined as distance. The organically modified layered clay mineral is contained in the polymer material in the elastic body, and the interlayer distance is preferably 3.7 to 5.0 nm, and more preferably 3.8 to 4.5 nm. When the interlayer distance is less than 3.7 nm, the effect of preventing the migration of the low molecular weight component is hardly obtained, and when the interlayer distance is more than 5.0 nm, the effect of capturing the low molecular weight component is almost lost.

  Furthermore, in the present invention, a filler, a processing aid, a crosslinking aid, a crosslinking accelerator, a crosslinking accelerator, which are generally used as a compounding agent in the rubber field, if necessary, within a range that does not significantly impair the effects of the invention. Auxiliaries, crosslinking retarders, tackifiers, dispersants, foaming agents and the like can be added. It should be noted that oily compounding agents such as a plasticizer, a softening agent, and an ionic conductive agent are liable to cause contamination of the photoreceptor and are preferably not used.

  Examples of the mixing method of these raw materials include a mixing method using a closed mixer such as a Banbury mixer and a pressure kneader, a mixing method using an open mixer such as an open roll, and the like.

  When the semiconductive elastic member in the present invention has a roller shape, the elastic body material composition is extruded into a tube shape, heat-cured to obtain a semiconductive elastic tube, and cut into a predetermined length The semiconductive elastic member of the present invention can be manufactured by inserting a conductive metal core, polishing the surface, or forming another functional layer on the surface. In addition, the elastic layer material is injected into a cylindrical mold containing a core metal, and after primary curing, the molded product is taken out from the mold, and further heated and cured (secondary curing) in a heating furnace. The semiconductive elastic member of the present invention can be manufactured by performing the same surface treatment as necessary.

  The processing conditions at this time may be appropriately selected according to the elastic layer raw material polymer, and are not particularly limited.

  Hereinafter, the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic cross-sectional view of an example in which the semiconductive elastic member of the present invention has a roller shape.

  As shown in FIG. 1A, the semiconductive elastic member of the semi-invention has at least a cylindrical or columnar core metal 11 having a conductive surface and a semiconductive property provided on the outer periphery thereof. It consists of an elastic body layer 12. The semiconductive elastic layer is shown as a single layer in this example, but may be a multilayer. Further, an adhesive layer may be formed between the core metal 11 and the elastic body layer 12 in order to obtain adhesiveness.

  Furthermore, a surface layer 13 may be formed on the surface of the elastic body layer 12 as shown in FIG. 1B in order to provide a function, particularly, adhesion prevention property of toner and toner external additives. Furthermore, a multilayer structure in which several intermediate layers or adhesive layers are arranged between the elastic body layer 12 and the surface layer 13 may be employed.

  The surface layer 13 is formed by irradiating the elastic layer surface with energy rays such as electron beam, ultraviolet ray, X-ray, microwave, etc., or curing the surface, or acrylic resin, polyurethane, polyamide, polyester, polyolefin, silicone resin, etc. And a non-adhesive resin or a silicone-based reactive surface treatment agent.

  In addition, when the surface layer 13 is provided, also in the semiconductive elastic member which has a surface layer, the electrical resistance needs to show semiconductivity. In this case, with respect to the non-adhesive resin described above, an oxide such as carbon black, graphite, titanium oxide or the like, or a metal such as copper or silver is arranged as required to obtain a desired electric resistance value. Use.

  The degree of contamination of the photoreceptor varies depending on the method and degree of non-adhesive treatment of the surface. In the case of non-adhesive treatment in which the surface layer is formed with an extremely thin film, compared to the case where a thick film or a laminated surface layer is formed, contaminants are more easily transferred from the inside of the semiconductive elastic layer to the surface. Also, in the case of non-adhesive treatment in which a surface layer is formed only by surface treatment by irradiation with energy rays, the contaminants easily move from the inside of the semiconductive elastic layer to the surface. In the present invention, (a) an organically modified layered clay mineral and (b) an oligomer having an epoxy group are arranged to form a semiconductive elastic body layer. Contamination is prevented.

  In the present invention, it is essential that the component (a) and the component (b) are disposed in the semiconductive elastic layer, but when the conductive elastic layer is a multilayer, at least a half of the outermost layer is required. The component (a) and the component (b) may be disposed only in the conductive elastic body layer, or may be disposed other than the semiconductive elastic body layer such as the surface layer and the intermediate layer.

  The layered clay mineral spread between the layers exists in the layer containing low molecular weight components that contaminate the photoreceptor, and has the effect of preventing the migration of these contaminating components, but in the outer layer of the layer containing low molecular weight components. By being included, there is also an action of trapping the migration substance in the outer layer.

  The semiconductive elastic member of the present invention is an image forming apparatus such as an electrophotographic apparatus, a process cartridge in which a photosensitive member and an elastic member are integrally formed as a cartridge, and is detachable from the main body of the image forming apparatus. It is suitable as a semiconductive elastic member for electrophotography used in contact with the non-elastic member, that is, a charging member, a developing member, a transfer member and the like.

  FIG. 2 is a schematic configuration diagram of an electrophotographic apparatus having the elastic member of the present invention.

  Reference numeral 21 denotes an electrophotographic photosensitive member as a member to be charged. Usually, a drum-shaped electrophotographic photosensitive member 21a having a conductive property such as aluminum and a photosensitive layer 21a formed on the supporting member 21b is basically used. It is a photoreceptor. The shaft 21c is driven to rotate at a predetermined peripheral speed in the direction of the arrow in the figure.

  A charging roller 1 disposed in contact with the electrophotographic photosensitive member 21 to charge (primary charging) the electrophotographic photosensitive member to a predetermined polarity and potential includes a cored bar 11, an elastic layer 12 formed on the cored bar 11, and It consists of a surface layer 13 formed on the elastic layer 12, and both ends of the cored bar 11 are driven to rotate as the electrophotographic photosensitive member 21 is driven by a pressing means (not shown).

  By applying a predetermined direct current (DC) bias or direct current + alternating current (DC + AC) bias of the metal core 11 by the rubbing terminal 23a with the power source 23, the electrophotographic photosensitive member 21 is contact-charged to a predetermined polarity and potential. The The electrophotographic photosensitive member 21 whose peripheral surface is charged by the charging roller 1 is then subjected to exposure of target image information (laser beam scanning exposure, slit exposure of a manuscript image, etc.) by the exposure means 24, so that the peripheral surface has a target. An electrostatic latent image corresponding to the image information is formed.

  Next, the electrostatic latent image is sequentially visualized as a toner image by the developing unit 25. This toner image is then synchronized with the rotation of the electrophotographic photosensitive member 21 from a paper feeding unit (not shown) by the transfer unit 26 and transferred at a proper timing between the electrophotographic photosensitive member 21 and the transfer unit 26. Are sequentially transferred to the transfer material 27 conveyed to the substrate. Here, the transfer unit 26 is a transfer roller, and the toner image on the electrophotographic photosensitive member 21 side is transferred to the transfer material 27 by charging from the back of the transfer material 27 with the reverse polarity to the toner.

  The transfer material 27 having received the transfer of the toner image on the surface is separated from the electrophotographic photosensitive member 21 and conveyed to a fixing means (not shown) to receive image fixing and output as an image formed product. Alternatively, in the case of forming an image on the back side, it is conveyed to a re-conveying means to the transfer unit.

  The peripheral surface of the electrophotographic photosensitive member 21 after the image transfer is subjected to pre-exposure by the pre-exposure means 28, and residual charges on the electrophotographic photosensitive drum are removed (static elimination). Known means can be used for the pre-exposure means 28. For example, an LED chip array, a fuse lamp, a halogen lamp, a fluorescent lamp, etc. can be preferably exemplified. The pre-exposure means preferably has an exposure amount larger than the exposure amount of the exposure means described above in consideration of the charge removal effect. Further, the position of the pre-exposure means is not limited to this embodiment, and may be provided between the cleaning means 29 and the charging means (for example, the charging roller 1).

  The peripheral surface of the electrophotographic photosensitive member 21 that has been neutralized is cleaned by the cleaning means 29 to remove adhered contaminants such as transfer residual toner and transfer material waste, and is repeatedly used for image formation.

  The charging roller 1 may be driven and driven by the electrophotographic photosensitive member 21 driven to move the surface, or may not be rotated, or may move in a predetermined direction in the forward or reverse direction in the surface moving direction of the electrophotographic photosensitive member 21. You may make it actively rotate at a speed.

  In addition, when the electrophotographic apparatus is used as a copying machine, exposure is performed by reflecting or transmitting light from a document or by reading a document as a read signal, scanning a laser beam based on this signal, or driving an LED array. Or by driving a liquid crystal shutter array.

  Examples of the electrophotographic apparatus that can use the electroconductive elastic member for electrophotography of the present invention include copying machines, laser beam printers, LED printers, and electrophotographic application apparatuses such as an electrophotographic plate making system.

  The elastic member of the present invention can also be used as a conveying member such as a static eliminating member or a paper feed roller.

  In the present invention, as shown in FIG. 3, a plurality of members such as the electrophotographic photosensitive member 21, the charging member 1, the developing unit 25, and the cleaning unit 29 can be integrated into the process cartridge. The process cartridge can be detachably attached to the main body of the electrophotographic apparatus. For example, the charging member and the electrophotographic photosensitive member of the present invention, and if necessary, further a developing member and a cleaning member are integrally incorporated in the process cartridge, and can be attached and detached using guide means such as a rail of the electrophotographic apparatus main body. Can be configured.

  Hereinafter, the present invention will be described in more detail by way of examples. These do not limit the present invention in any way. In the following, unless otherwise specified, “part” means “part by mass”, and a commercially available high-purity product was used as a reagent or the like unless otherwise specified.

Example 1
Epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer “Epichromer CG105” (trade name, manufactured by Daiso Corporation) and epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer “Epichromer EPION301” 50 parts by trade name, manufactured by Daiso Corporation, 1 part zinc stearate as processing aid, 5 parts zinc oxide as vulcanization accelerator, MT carbon black “Thermax Flow Foam N990” as filler (trade name, CANCARB) 35 parts organically modified layered clay mineral “Esven NX” (trade name, manufactured by Hojun Co., Ltd., bentonite whose interlayer is modified with dimethyloctadecyl ammonium ion), epoxy as an epoxy group oligomer Butadiene "Adekaiser BF1000" (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), dibenzothiazolyl disulfide "Noxeller DM" (trade name, manufactured by Ouchi Shinsei Chemical Co., Ltd.) as a vulcanizing agent, tetra 1 part of methylthioram disulfide “Noxeller TS” (trade name, manufactured by Ouchi Shinsei Chemical Co., Ltd.) and 1.2 parts of sulfur were mixed with an open roll to obtain an unvulcanized rubber composition.

  The obtained unvulcanized rubber composition was extruded into a tube shape by a vent type rubber extruder (φ50 mm, L / D = 16) manufactured by EM Giken Co., Ltd., and 30 ° C. at 160 ° C. with pressurized steam using a vulcanized can. The rubber tube having an outer diameter of 15 mm, an inner diameter of 5.5 mm, and a length of 250 mm was obtained.

  A conductive hot melt adhesive was applied to a central portion 232 mm of a cylindrical conductive core bar (steel, surface is nickel-plated) having a diameter of 6 mm and a length of 256 mm, and dried at 80 ° C. for 30 minutes. The rubber tube was press-fitted and subjected to secondary vulcanization and adhesion treatment at 160 ° C. for 2 hours in a hot air furnace. After both ends of the rubber were cut to make the length of the rubber part 232 mm, the rubber part was polished with a rotating grindstone to have a drum-shaped elastic body layer with an end diameter of 8.3 mm and a center diameter of 8.5 mm. Got Laura.

The surface of the elastic layer of this roller is rotated and irradiated with ultraviolet rays at an ultraviolet intensity of 40 mW / cm ² for 10 minutes using an ultraviolet irradiation device (185 nm and 245 nm are the main components of wavelength) for electrophotography. A semiconductive elastic member was obtained.

  Several strips of 2mm thickness are cut out from this elastic layer into strips, spread on an aluminum sample holder so that the measurement surface is evenly aligned, and the X-ray diffractometer “TTR-2” (trade name, Rigaku Corporation) The interlayer distance of the layered mineral was measured at 2θ = 1 to 10 ° by the 2θ / θ scanning method. The X-ray diffraction measurement was performed using CuKα rays with an X-ray output of 50 kV and 300 mA, a divergence slit of 0.20 mm, a divergence longitudinal limit slit of 10.0 mm, a scattering slit opened, a light receiving slit of 0.15 mm, and an incident monochromator used. It was. As a result, the interlayer distance was 3.97 nm.

  This electrophotographic semiconductive elastic member is incorporated as a charging roller into the process cartridge “Toner Cartridge EP-85” (trade name, manufactured by Canon Inc.) shown in FIG. 3 and is used in a harsh environment of 40 ° C./95% RH. The sample was allowed to stand for 30 days, and an acceleration test for the photoreceptor contamination was conducted. As a result, the migration of contaminants from the electrophotographic semiconductive elastic member to the photoreceptor was not confirmed.

  Next, this cartridge was subjected to half-tone image formation in a room temperature and humidity environment by using the electrophotographic apparatus “Laser Shot LBP-2510” (trade name, manufactured by Canon Inc.) shown in FIG. When the later image evaluation was performed and the following criteria were evaluated, the evaluation was A.

(Image evaluation criteria after leaving the harsh environment)
A evaluation: No migration of contaminants from the electroconductive semiconductive elastic member for electrophotography to the photosensitive member was confirmed, and an image of good quality was obtained and “good”.
B evaluation: When the contaminants move to the surface, the contaminants remain on the surface of the electroconductive semiconductive elastic member or the photoreceptor, and the charging characteristics, development characteristics, and transfer characteristics of the portions change, and the electrophotographic semi-conductors change. An image defect occurs in the period of the circumferential length of the conductive elastic member or the photosensitive member, and “bad”.
C evaluation: When contaminants migrate to the surface, a lot of contaminants remain on the surface of the electroconductive semiconductive elastic member for electrophotography and the photoreceptor, and the charging characteristics, development characteristics, and transfer characteristics of the portions change considerably, and electrophotography Many image defects occur in the period of the circumferential length of the semiconductive elastic member and the photosensitive member, and “very bad”.

Example 2
A semiconductive elastic member for electrophotography was obtained in the same manner as in Example 1 except that 5 parts of epoxidized butadiene “Adekarange EPB1200” (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) was used as the oligomer having an epoxy group. The interlayer distance of the layered clay mineral in this elastic body was 4.03 nm. Further, in the same manner as in Example 1, a photoreceptor contamination test was performed by image output. As a result, even after being left in a harsh environment, no migration of contaminants from the electroconductive semiconductive elastic member to the photosensitive member was confirmed, and an image of good quality was obtained (A evaluation).

Example 3
As the surface treatment, instead of ultraviolet irradiation, the elastic body layer was dipped in a silicone-based reactive surface treatment solution “SAT-500F” (trade name: manufactured by Shinko Giken Co., Ltd.) for 1 minute, and then at 100 ° C. for 10 minutes. A semiconductive elastic member for electrophotography was obtained in the same manner as in Example 1 except that heat treatment was performed. At this time, the film thickness of the cured product of the surface treatment liquid was 0.1 μm or less. The interlayer distance of the layered clay mineral in this elastic layer was 3.97 nm. As a result of conducting the photoconductor contamination test by image output in the same manner as in Example 1, no migration of contaminants from the electrophotographic semiconductive elastic member to the photoconductor was confirmed even after being left in a harsh environment, and an image of good quality was obtained. Obtained (A evaluation).

Example 4
Example of surface treatment except that instead of UV irradiation, the elastic layer is dipped for 1 minute in a silicone-based reactive surface treatment solution “SAT-500F” (trade name) and then heat treated at 100 ° C. for 10 minutes. In the same manner as in Example 2, an electrophotographic semiconductive elastic member was obtained. At this time, the film thickness of the cured product of the surface treatment liquid was 0.1 μm or less. The interlayer distance of the layered clay mineral in this elastic body was 4.03 nm. As a result of conducting the photoconductor contamination test by image output in the same manner as in Example 1, no migration of contaminants from the electrophotographic semiconductive elastic member to the photoconductor was confirmed even after being left in a harsh environment, and an image of good quality was obtained. Obtained (A evaluation).

Example 5
A semiconductive elastic member for electrophotography was obtained in the same manner as in Example 1 except that no surface treatment was performed. The interlayer distance of the layered clay mineral in this elastic layer was 3.97 nm. This electrophotographic semiconductive elastic member is incorporated as a charging roller into the process cartridge “Toner Cartridge EP-85” (trade name, manufactured by Canon Inc.) shown in FIG. 3 and is used in a harsh environment of 40 ° C./95% RH. The sample was allowed to stand for 30 days, and an acceleration test for the photoreceptor contamination was conducted. As a result, no migration of contaminants from the electrophotographic semiconductive elastic member to the photoreceptor was confirmed even after being left in a harsh environment. However, since the surface treatment was not performed, there was an adverse effect that the toner and the external additive adhered to the surface of the electroconductive semiconductive member. Therefore, image output was not performed.

Comparative Example 1
A semiconductive elastic member for electrophotography was obtained in the same manner as in Example 1 except that the conductive elastic layer material did not contain an organically modified layered clay mineral and an oligomer having an epoxy group. As a result of conducting the photoconductor contamination test by image output in the same manner as in Example 1, the contaminants oozed out of the electrophotographic semiconductive member during severe storage and adhered to the photoconductor and the electroconductive semiconductive elastic member. It was clearly confirmed that the image was defective (C evaluation).

Comparative Example 2
A semiconductive elastic member for electrophotography was obtained in the same manner as in Example 3 except that the conductive elastic layer material did not contain an organically modified layered clay mineral and an oligomer having an epoxy group. As a result of conducting the photoconductor contamination test by image output in the same manner as in Example 1, the contaminants oozed out of the electrophotographic semiconductive member during severe storage and adhered to the photoconductor and the electroconductive semiconductive elastic member. It was clearly confirmed that the image was defective (C evaluation).

Comparative Example 3
A semiconductive elastic member for electrophotography was obtained in the same manner as in Example 1 except that the conductive elastic layer material did not contain an epoxy group-containing oligomer. The interlayer distance of the layered clay mineral in this elastic layer was 3.52 nm. As a result of conducting the photoconductor contamination test by image output in the same manner as in Example 1, the contaminants oozed out from the electroconductive semiconductive member during severe storage and adhered to the photoconductor and the electroconductive semiconductive elastic member. The image defect seen was confirmed (B evaluation).

Comparative Example 4
A semiconductive elastic member for electrophotography was obtained in the same manner as in Example 1 except that the conductive elastic layer material did not contain an organically modified layered clay mineral. As a result of conducting the photoconductor contamination test by image output in the same manner as in Example 1, a considerable amount oozes out from the electrophotographic semiconductive member during severe storage and adheres to the photoconductor and the electroconductive semiconductive elastic member. An image defect that appears to be a contaminated material was confirmed (B evaluation).

  Table 1 shows the material composition, surface treatment, and evaluation results of the elastic layer of the above charging roller.

注)組成中の記号は下記を示す。
ＣＧ１０５：ダイソー株式会社製の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３元共重合体「エピクロマー ＣＧ１０５」（商品名）
ＥＰＩＯＮ：ダイソー株式会社製の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３元共重合体「エピクロマー ＥＰＩＯＮ３０１」（商品名）
ＭＴカーボンブラック：ＣＡＮＣＡＲＢ社製のＭＴカーボンブラック「サーマックスフローフォームＮ９９０」（商品名）
ＢＦ１０００：旭電化工業株式会社製のエポキシ化ブタジエン「アデカイザー ＢＦ１０００」（商品名）
ＥＰＢ１２００：旭電化工業株式会社製のエポキシ化ブタジエン「アデカイザー ＥＰＢ１２００」（商品名）
ＤＭ：ジベンゾチアゾリルジスルフィド
ＴＳ：テトラメチルチオラムジスルフィド
＊）表面処理は、それぞれＵＶ：紫外線照射、ＳＡＴ：シリコーン系反応性表面処理剤処理を示す。

Note) Symbols in the composition are as follows.
CG105: Epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer “Epichromer CG105” (trade name) manufactured by Daiso Corporation
EPION: Epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer “Epichromer EPION301” (trade name) manufactured by Daiso Corporation
MT Carbon Black: MT carbon black “Thermax Flow Foam N990” (trade name) manufactured by CANCARB
BF1000: Epoxidized butadiene “Adekaiser BF1000” (trade name) manufactured by Asahi Denka Kogyo Co., Ltd.
EPB1200: Epoxidized butadiene “Adekaiser EPB1200” (trade name) manufactured by Asahi Denka Kogyo Co., Ltd.
DM: dibenzothiazolyl disulfide TS: tetramethylthioram disulfide *) surface treatment indicates UV: ultraviolet irradiation, SAT: silicone-based reactive surface treatment treatment, respectively.

  In Comparative Examples 1 to 4, the polymer constituting the charging roller does not contain at least one of the organic modified layered clay mineral of the present invention and the epoxidized butadiene oligomer. In Comparative Example 3, there is an organic modified clay mineral. In addition, comparatively small contaminants can be adsorbed and retained between the layers. In Comparative Example 4, the epoxy group of the epoxidized butadiene oligomer reacts with chlorine to prevent contamination caused by chlorine. The effect as invented could not be obtained. As a result, when the electroconductive semiconductive elastic member is brought into contact with the photoconductor and left for a long time in a harsh environment, an image defect due to the migration material from the elastic layer of the member contaminating the photoconductor is caused. Occurred.

  As is apparent from Table 1, when the electrophotographic semiconductive elastic member of the present invention is used as a charging roller, even when left in a harsh environment for a long time in contact with the photoreceptor, the transition from the elastic body layer occurs. There is almost no substance, and image defects due to photoconductor contamination do not occur.

It is a schematic cross section of the semiconductive elastic member (roller shape) of the present invention. 1 is a schematic cross-sectional view of an electrophotographic apparatus according to the present invention. It is a typical sectional view of a process cartridge in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Charging roller 11 Core metal 12 Elastic body layer 13 Surface layer 21 Electrophotographic photoreceptor 21a Photosensitive layer 21b Conductive support 21c Shaft 23 Power supply 23a Rub terminal 24 Exposure means 25 Development means 26 Transfer means 27 Transfer material 28 Pre-exposure means 29 Cleaning means T Toner

Claims (4)

  The semiconductive elastic layer is cured from a semiconductive elastic layer material containing (a) an organically modified layered clay mineral and (b) an oligomer having an epoxy group. Elastic member.   The semiconductive elastic member for electrophotography according to claim 1, wherein the oligomer having an epoxy group is an epoxidized butadiene oligomer.   The semiconductive elastic member for electrophotography according to claim 1 or 2, wherein the layered clay mineral is bentonite.   The electron according to any one of claims 1 to 3, wherein an interlayer distance based on the layered clay mineral is observed at 3.7 nm to 5.0 nm as measured by X-ray diffraction of the semiconductive elastic layer. Semiconductive elastic member for photography.

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