JP2011059480A - Charging roller, electrophotographic device and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress corrosion of the surface of the conductive support shaft of a charging roller having a conductive elastic layer having rubber containing halogen atoms. <P>SOLUTION: The charging roller includes: the conductive support shaft whose surface is composed of metal; a conductive adhesive layer disposed on the outer periphery of the support shaft; and the conductive elastic layer which is disposed on the conductive adhesive layer, and has the rubber containing the halogen atoms. The conductive adhesive layer comprises epoxy resin, fatty acid metal salt and phosphite. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a charging roller, an electrophotographic apparatus, and a process cartridge.

  The charging roller having a conductive elastic layer containing ionic conductive rubber such as epichlorohydrin rubber on the peripheral surface of the conductive support shaft is a chloride derived from chlorine and the like liberated in the conductive elastic layer under high temperature and high humidity conditions. As a result, there is a problem that the surface of the conductive support shaft may corrode. For such a problem, Patent Document 1 discloses a conductive roller in which a conductive adhesive layer is provided between a conductive support shaft and a conductive elastic layer, and the conductive adhesive layer includes a phenol resin, an epoxy resin, and a conductive agent. Proposed. It is disclosed that the oxirane ring of the epoxy resin can trap hydrogen halide generated from the conductive elastic layer and prevent the conductive support shaft from being rusted.

JP 2006-208447 A

  However, in recent years, there has been an increasing demand for more stable performance of electrophotographic apparatuses. Under such circumstances, the inventors examined the charging roller according to the invention of Patent Document 1, and as a result, the conductive elastic layer sometimes peeled off the conductive support shaft with long-term use.

  Therefore, the present invention is directed to providing a charging roller that can better suppress the peeling of the conductive elastic layer from the conductive support shaft and can exhibit stable charging performance over a long period of time even after long-term use. It is a thing. Another object of the present invention is to provide an electrophotographic apparatus and a process cartridge that can stably form a high-quality electrophotographic image.

The charging roller according to the present invention includes a conductive support shaft whose surface is made of metal, a conductive adhesive layer provided on the outer periphery thereof, and a rubber containing halogen atoms provided on the conductive adhesive layer. A charging roller having a conductive elastic layer having
The conductive adhesive layer contains an epoxy resin, a fatty acid metal salt, and a phosphite.

  In addition, an electrophotographic apparatus according to the present invention includes the above-described charging roller and an electrophotographic photosensitive member.

  Furthermore, a process cartridge according to the present invention includes a charging roller and an electrophotographic photosensitive member, and is configured to be detachable from a main body of the electrophotographic apparatus.

  According to the present invention, the occurrence of corrosion on the surface of the conductive support shaft under high-humidity conditions can be extremely well suppressed, and a charging roller that stably exhibits excellent charging performance even in various environments can be obtained. did it. As a result, an electrophotographic apparatus and a process cartridge that can stably provide excellent electrophotographic images under various environments can be obtained.

It is the schematic of the charging roller which concerns on this invention. 1 is a schematic view of an electrophotographic apparatus according to the present invention. It is the schematic of the process cartridge using the charging roller which concerns on this invention.

  FIG. 1 is a sectional view of a charging roller according to the present invention. A conductive support shaft 101 having a metal surface, a conductive elastic layer 103 having a halogen atom-containing rubber bonded to the peripheral surface of the conductive support shaft 101 by a conductive adhesive layer 102, and A surface layer 104 is provided accordingly. The conductive adhesive layer contains an epoxy resin, a fatty acid metal salt, and a phosphite.

<Conductive adhesive layer>
The conductive adhesive layer 102 contains an epoxy resin, a fatty acid metal salt, and a phosphite. The technical meaning of including these materials in the adhesive layer will be described. As disclosed in Patent Document 1, the corrosion of the conductive shaft core can be suppressed by interposing a layer containing an epoxy resin between the conductive support shaft and the conductive elastic layer containing epichlorohydrin rubber. This is considered to be because the halogen ions generated in the conductive elastic layer react with the oxirane ring of the epoxy resin to generate chlorohydrin, thereby preventing the halogen ions from reaching the surface of the conductive support shaft. .

  However, as described above, the charging roller according to Patent Document 1 has also been found that the conductive elastic layer may be peeled off from the conductive support shaft when used for a long period of time, which may result in non-uniform charging. Then, when detailed observation was performed on the above-described peeling, it was found that corrosion was generated on the surface of the conductive support shaft, thereby peeling at the interface between the conductive shaft core and the adhesive layer. The present inventors determined that such corrosion was caused by excessive chlorine ions that could not be captured by the oxolane ring reaching the surface of the conductive support shaft. Here, from the bottom of page 73 to the bottom line of “Polymer additive development technology”, CMC Co., Ltd., published on June 20, 1998, 1 edition) With regard to stabilization of vinyl chloride, it is described that an excellent stabilization effect is exhibited by the combined use of an epoxy compound and metal soap. Also, on page 74, lines 1 to 3 of the same document, it is disclosed that chlorohydrin produced by the reaction of an epoxy compound and HCl gives HCl to metal soap to regenerate the epoxy ring. Based on such disclosure, the present inventors considered that an aliphatic acid metal salt is allowed to coexist with an epoxy resin in an adhesive layer to regenerate an oxolane ring that has reacted with chloride ions. However, it is expected that the regeneration of the oxolane ring will produce metal chloride as a by-product, which will be the source of chlorine ions. Accordingly, the present inventors disclosed Abe, Sudo, “New Edition, Plastic Compounding Agents—Basics and Applications”, Taiseisha Co., Ltd., issued on November 30, 1987, second printing, page 96, lines 19-21. Based on the above, it was considered to further contain a phosphite in the conductive adhesive layer. That is, in the above-mentioned document, phosphite as a stabilizer for PVC is effective as a chelator for preventing decomposition by sandwiching a metal oxide formed by reaction of a stabilizer and hydrochloric acid. It is disclosed. That is, the present inventors have considered that metal chloride produced as a by-product by regeneration of the oxolane ring is stabilized by a phosphite that is a chelator. Based on these considerations, electrification in which a conductive support shaft and a conductive elastic layer containing epichlorohydrin rubber are bonded to a conductive adhesive layer using a conductive adhesive containing an epoxy resin, a fatty acid metal salt and a phosphite. Rollers were manufactured and evaluated. As a result, in the charging roller according to Patent Document 1, it was recognized that peeling hardly occurred even after long-term use in which peeling occurred, and the adhesive layer described above contributed to the achievement of the object of the present invention. .

(Epoxy resin)
The following can be illustrated as an epoxy resin contained in a conductive contact bonding layer. Bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, glycidyl ester type epoxy resin, polyfunctional phenol novolac type epoxy resin, and resins modified with other resins based on these. The epoxy resin is preferably liquid at normal temperature or soluble in a solvent, and the epoxy equivalent is preferably 100 or more and 5000 or less, particularly 150 or more and 300 or less. By setting the epoxy equivalent in this range, it is possible to obtain an adhesive having good adhesive force and sufficient chlorine ion trapping ability. Moreover, it is preferable that an epoxy resin is 5 mass% or more and 50 mass% or less in solid content of an adhesive bond layer. When it is in this range, the film strength and rust prevention effect as an adhesive are improved.

(Fatty acid metal salt)
The following can be illustrated as a fatty acid which comprises a fatty-acid metal salt. Butyric acid, 2-ethylhexoic acid, lauric acid, stearic acid, ricinoleic acid, naphthenic acid, montanic acid and the like. Preferably, the molecular weight of the fatty acid is 70 to 500, in particular 120 to 300. By setting the molecular weight of the fatty acid within this range, the thermal stability of the resin constituting the adhesive is not lowered, and the compatibility with the resin constituting the adhesive is improved. Examples of the metal from which the fatty acid metal salt is derived include atoms of Groups 1, 2, 12, 13, and 14 of the periodic table. Specific examples include lithium, magnesium, calcium, strontium, barium, zinc, and tin. Preferred are Group 2 and Group 12. The addition amount of the fatty acid metal salt is preferably 0.5 parts by mass or more and 25 parts by mass or less with respect to the resin content in the solid content of the adhesive.

(Phosphorous ester)
The following can be illustrated as a phosphite. Triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, triisodecyl phosphite, tri-2-ethylhexyl phosphite, diphenylnonylphenyl phosphite, trinonylphenyl phosphite and the like. Preferably, the molecular weight is 200 or more and 1200 or less. If it exists in this range, compatibility with adhesive resin is favorable. More preferably, it is 500 or more and 700 or less. The addition amount is preferably 0.5 parts by mass or more and 25 parts by mass or less based on the resin content in the solid content.

(Adhesive component)
The conductive adhesive layer contains a resin as an essential component for fulfilling its adhesion function. As such a resin, a resin such as a thermosetting resin or a thermoplastic resin is used. Specific examples of the resin as an adhesive component to be contained in the adhesive for forming the conductive adhesive layer include urethane resin, acrylic resin, acrylic resin, polyamide resin, polyolefin resin, phenol resin, and the like. In particular, a thermosetting phenol resin is preferred because the water vapor and gas permeability of the cured resin are low. In addition to these resins, the adhesive may be mixed with a rubber component in order to improve heat resistance and adhesive strength. Examples thereof include natural rubber, butadiene rubber, styrene butadiene rubber (SBR), nitrile rubber, ethylene propylene rubber (EPDM), nitrile butadiene rubber (NBR), butyl rubber, and urethane rubber. In particular, nitrile butadiene rubber is preferable because it can increase the adhesive force between the conductive elastic layer and the conductive adhesive layer.

(Other materials)
In addition to the above essential components, the conductive adhesive layer further includes a conductive agent, a plasticizer, a thixotropy imparting agent, a pigment, a dye, an anti-aging agent, an antioxidant, and a dispersing agent as long as the object of the present invention is not impaired. A solvent or the like may be blended.

<Conductive elastic layer>
The conductive elastic layer is obtained by vulcanizing a layer of an unvulcanized rubber composition formed on the above-described conductive adhesive layer. The unvulcanized rubber composition of the present invention contains a halogen atom such as chlorine. Examples of the rubber component constituting the unvulcanized rubber composition include epichlorohydrin rubber, chloroprene rubber (CR), fluorine rubber, and the like. If necessary, natural rubber, butadiene rubber, styrene butadiene rubber (SBR), nitrile rubber, ethylene propylene rubber (EPDM), nitrile butadiene rubber (NBR), butyl rubber, silicone rubber, urethane rubber, etc. may be mixed. .

  Examples of the conductive powder dispersed in the unvulcanized rubber composition include carbons such as carbon black and conductive carbon, metal oxides such as graphite, titanium oxide, tin oxide, and zinc oxide, Cu, Ag, and the like. Examples thereof include metal powder and conductive fibers. Further, an ionic conductive agent or the like may be used. 5 mass parts-200 mass parts is added with respect to 100 mass parts of said polymer raw materials.

  Examples of vulcanizing agents include sulfur, metal oxides, and organic oxides. Examples of inorganic fillers include carbon black, talc, clay, and calcium carbonate. Other known vulcanization accelerators, process oils, and the like are appropriately added. .

  The elastic layer is preferably formed by a known method such as extrusion molding, injection molding, or compression molding after mixing the above-mentioned conductive elastic material with a closed mixer. The elastic layer may be produced by directly forming a conductive elastic body on a conductive support shaft provided with an adhesive layer. Alternatively, a conductive elastic body previously formed into a tube shape may be formed on the conductive support shaft.

(Conductive support shaft with metal surface)
The conductive support shaft 101 whose surface is made of metal has conductivity in order to supply power to the surface of the charging roller via the conductive support. In the structure, at least the surface is made of metal. As the conductive support shaft whose surface is made of metal, metal (made of alloy) such as iron, copper, stainless steel, aluminum, aluminum alloy, nickel, or the like can be used. Moreover, what provided the electroconductive layer, such as a metal, on the surface of a material with no electroconductivity may be used.

<Surface layer>
A surface layer may be provided on the surface of the conductive elastic layer for the purpose of adjusting resistance, for example. As the surface layer, known materials can be used, and examples thereof include a binder, a conductive agent, a roughening agent, and insulating inorganic fine particles. As the binder, a resin such as a thermosetting resin or a thermoplastic resin is used. Examples of the binder for the surface layer of the present invention include urethane resins, fluorine resins, silicone resins, acrylic resins, polyamide resins and the like. A urethane resin obtained by crosslinking a lactone-modified acrylic polyol with an isocyanate is particularly preferably used. Examples of the conductive agent include conductive particles such as carbon black, graphite, conductive titanium oxide, and conductive metal oxide of conductive tin oxide, or conductive composite particles obtained by combining the conductive particles with other particles. Can be mentioned. By appropriately dispersing these, a desired electric resistance value can be obtained. The roughening agent can form minute irregularities on the surface of the charging member, and can improve the charging uniformity. Fine irregularities on the surface are particularly effective for the DC charging method. As the roughening agent, it is preferable to use fine particles made of a polymer compound such as urethane fine particles, silicone fine particles, and acrylic fine particles. The surface layer can be formed by a coating method such as spray coating or dipping coating. Or it can form by adhere | attaching or coat | covering the sheet-shaped or tube-shaped layer beforehand formed into the film thickness of predetermined thickness. Alternatively, a method of curing and molding the material into a predetermined shape in the mold can also be used.

  When the layer is formed by a coating method, the solvent used in the coating solution may be any solvent that can dissolve the binder resin, and examples thereof include the following. Alcohols such as methanol, ethanol and isopropanol, and ketones such as acetone and methyl ethyl ketone.

(Electrophotographic equipment)
FIG. 2 is a sectional view of an electrophotographic apparatus using the charging roller of the present invention. The electrophotographic apparatus includes an electrophotographic photosensitive member 301, a charging roller 302 for charging the electrophotographic photosensitive member 301, a latent image forming device 308, a developing device 303, a transfer device 305 for transferring to a transfer material 304, a cleaning blade 307, a fixing device 306, and the like. is doing. The electrophotographic photoreceptor 301 is a rotary drum type having a photosensitive layer on a conductive substrate. The electrophotographic photosensitive member 301 is rotationally driven in the direction of the arrow at a predetermined peripheral speed (process speed). The charging roller 302 is placed in contact with the electrophotographic photosensitive member 301 by being pressed with a predetermined force. The charging roller 302 is driven to rotate in accordance with the rotation of the electrophotographic photosensitive member 301, and applies a predetermined DC voltage from the charging power source 313 to charge the electrophotographic photosensitive member 301 to a predetermined potential. As the latent image forming apparatus 308 that forms a latent image on the electrophotographic photosensitive member 301, for example, an exposure apparatus such as a laser beam scanner is used. An electrostatic latent image is formed by performing exposure corresponding to image information on the uniformly charged electrophotographic photosensitive member 301. The developing device 303 has a contact type developing roller disposed in contact with the electrophotographic photosensitive member 301. The toner electrostatically processed to the same polarity as the photosensitive charging polarity is developed by reversal, and the electrostatic latent image is visualized and developed into a toner image. The transfer device 305 has a contact-type transfer roller. The toner image is transferred from the electrophotographic photosensitive member 301 to a transfer material 304 such as plain paper. The cleaning blade 307 mechanically scrapes off and collects the transfer residual toner remaining on the electrophotographic photosensitive member 301. The fixing device 306 includes a heated roll or the like, and fixes the transferred toner image to the transfer material 304.

  FIG. 3 is a cross-sectional view of a process cartridge in which the charging roller 302, the electrophotographic photosensitive member 301, the developing device 303, the cleaning blade 307, and the like according to the present invention are integrated and configured to be detachable from the main body of the electrophotographic device. It is.

  Specific examples of the present invention will be described below. In addition, the material changed and used in each Example is used by the same mass part as the material before a change.

<Example 1>
The following materials were prepared as materials for the charging roller.

(Conductive support shaft)
As a conductive support shaft, a cylindrical rod having a total length of 252 mm and a diameter of 6 mm prepared by electroless nickel plating on the surface of free-cutting steel was prepared.

(Preparation of adhesive for forming conductive adhesive layer)
The mixture of the materials shown in Table 1 below is mixed in a 450 mL glass bottle with 210 g of the above mixed solution and 200 g of glass beads having an average particle size of 0.8 mm as a medium, and dispersed for 24 hours using a paint shaker disperser. An adhesive was obtained.

(Creation of conductive adhesive layer)
The adhesive prepared above was applied to a portion excluding both ends 13 mm of the conductive support shaft using a roll coater. Thereafter, the film was heated in an oven at 170 ° C. for 20 minutes, and the film thickness of the adhesive on which the conductive adhesive layer was formed was 8 μm on average.

(Elastic layer)
The materials shown in Table 2 below were mixed with an open roll to prepare an unvulcanized rubber composition.

(Creation of conductive roll)
An apparatus having a supply mechanism for a conductive support shaft and a discharge mechanism for an elastic roller was prepared in the crosshead extruder. The conductive support shaft with an adhesive layer prepared above was continuously supplied from the supply mechanism to the crosshead. The conveyance speed of the conductive support shaft was 60 mm / sec. A die having an inner diameter of 9.0 mm was attached to the crosshead, and the temperature of the extruder and the crosshead was adjusted to 80 ° C. in advance. A layer of unvulcanized rubber composition supplied from an extruder was formed on the peripheral surface of the adhesive layer of the conductive support shaft supplied to the crosshead. At that time, the conductive support shaft on which the layer of the unvulcanized rubber composition is formed is pushed by the conductive support shaft that is continuously supplied, thereby passing through the cross head and being discharged from the cross head. The Next, the conductive support shaft on which the layer of the unvulcanized rubber composition is formed is put into a hot air vulcanizing furnace that is preliminarily heated to an atmosphere of 170 ° C. by hot air, heated for 60 minutes, The layer of the vulcanized rubber composition was cured to form an elastic layer. Thereafter, the elastic layer at the end was cut and removed so that the length of the elastic layer was 228 mm. Further, the surface of the elastic layer was polished with a rotating grindstone to obtain a crown-shaped conductive elastic roller having an end diameter of 8.45 mm and a center diameter of 8.5 mm.

(Preparation of surface layer)
Methyl isobutyl ketone was added to the caprolactone-modified acrylic polyol solution to adjust the solid content to 18% by mass. A mixed solution was prepared by mixing 555.6 parts by mass of this solution and 100 parts by mass of the solid content of the caprolactone-modified acrylic polyol solution in the solution with the materials shown in Table 3 below.

  In a 450 mL glass bottle, 210 g of the mixed solution and 200 g of glass beads having an average particle diameter of 0.8 mm as a medium were mixed and dispersed for 24 hours using a paint shaker disperser. After dispersion, 5.44 parts by mass of crosslinked acrylic particles “MR50G” (trade name, manufactured by Soken Chemical Co., Ltd.) as resin particles were added (an equivalent of 20 parts by weight with respect to 100 parts by weight of acrylic polyol), and then 30 more. Dispersed for a minute to obtain a coating material for forming the surface layer. This surface layer-forming coating material is dipped once onto the conductive elastic roller obtained above, air-dried at room temperature for 30 minutes or more, then dried in a hot air circulating dryer set at 90 ° C. for 1 hour, and further 160 It dried for 1 hour with the hot air circulation dryer set to ° C, and formed the surface layer on the conductive substrate. The dipping coating dipping time is 9 seconds, the dipping coating lifting speed is adjusted so that the initial speed is 20 mm / s, and the final speed is 2 mm / s. Between 20 mm / s and 2 mm / s is linear with respect to time. The speed was changed. Thus, a charging roller having a surface layer on a conductive substrate was produced. The obtained charging roller was evaluated by the following method.

<1> Leaving test under high temperature and high humidity After placing the developing roller in an environment of a temperature of 40 ° C. and a humidity of 95% for 2 months, the appearance is visually observed, and the conductive elastic layer and the conductive support shaft are The presence or absence of swelling due to peeling and the extent thereof were evaluated according to the following criteria.

  A: The occurrence of swelling is not recognized.

  B: Slight swelling is observed in the vicinity of both end portions outside the charged region.

  C: Swelling is observed in the charged region.

  D: Many blisters are recognized in the charged region.

<2> Image Evaluation The charging roller subjected to the above evaluation <1> was mounted on an electrophotographic laser printer (trade name: LBP5400, manufactured by Canon Inc.). In the laser printer, the output speed of the recording medium was 200 mm / sec and the image resolution was 600 dpi. All images were evaluated at low temperature and low humidity (15 ° C., 10%), and a halftone image (an image in which a horizontal line having a width of 1 dot and an interval of 2 dots was drawn in a direction perpendicular to the rotation direction of the photoreceptor) was output. The output image was visually evaluated according to the following criteria.
A: No white haze-like image defect due to swelling is observed.
B: A white haze-like image defect due to swelling is slightly observed.
C: Many white haze-like image defects due to swelling are observed.
<Examples 2-3>
The “trinonylphenyl phosphite” of the conductive adhesive of Example 1 was changed to “triphenyl phosphite” or “trioctadecyl phosphite”. Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Examples 4 to 6>
“Zinc stearate” in the conductive adhesives of Examples 1 to 3 was changed to “aluminum stearate”. Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Examples 7 to 9>
In the conductive adhesives of Examples 1 to 3, “zinc stearate” was changed to “zinc butyrate”. Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Examples 10 to 12>
In the conductive adhesives of Examples 1 to 3, “zinc stearate” was changed to “potassium butyrate”. Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Examples 13 to 15>
In the conductive adhesives of Examples 1 to 3, “zinc stearate” was changed to “zinc montanate”. Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Examples 16 to 18>
In the conductive adhesives of Examples 1 to 3, “zinc stearate” was changed to “aluminum montanate”. Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Examples 19 to 21>
In the conductive adhesives of Examples 1 to 3, “zinc stearate” was changed to “calcium 2-ethylhexoate”. Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Examples 22 to 24>
In the conductive adhesives of Examples 1 to 3, “zinc stearate” was changed to “sodium 2-ethylhexoate”. Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Examples 25-27>
In the conductive adhesives of Examples 1 to 3, “zinc stearate” was changed to “calcium laurate”. Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Examples 28 to 30>
In the conductive adhesives of Examples 1 to 3, “zinc stearate” was changed to “lithium laurate”. Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Example 31>
In the conductive adhesive of Example 1, NBR was not used, but the epoxy resin was changed to a bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., grade “834”: epoxy equivalents 230 to 270). Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Example 32>
In the conductive adhesive of Example 1, the resol type phenol resin was not used, and the epoxy resin was changed to a bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., grade “834”: epoxy equivalents 230 to 270). Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Example 33>
In the conductive adhesive of Example 1, the resol type phenol resin and NBR were not used, and the epoxy resin was changed to a bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., grade “834”: epoxy equivalent 230-270). . Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.
<Example 34>
The unvulcanized rubber composition used for forming the elastic layer of Example 1 was changed to that shown in Table 4 below. Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 1.

<Example 35>
In the conductive adhesive of Example 34, NBR was not used, and the epoxy resin was changed to a bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., grade “834”: epoxy equivalents 230 to 270). Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 34.
<Example 36>
In the conductive adhesive of Example 34, the phenol resin was not used, and the epoxy resin was changed to a bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., grade “834”: epoxy equivalents 230 to 270). Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 34.
<Example 37>
In the conductive adhesive of Example 34, the phenol resin and NBR were not used, and the epoxy resin was changed to a bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., grade “834”: epoxy equivalents 230 to 270). Otherwise, a charging roller was prepared and evaluated in the same manner as in Example 34.
<Example 38>
A conductive adhesive was prepared in the same manner as in Example 1 except that “carbon black” was not used in the conductive adhesive of Example 1. A charging roller was prepared and evaluated in the same manner as in Example 1 except that this conductive adhesive was used.
<Examples 39 to 41>
In the conductive adhesive of Example 38, “NBR”, “Resol type phenol resin” or “NBR” and “Resol type phenol resin” were not used, and the epoxy resin was bisphenol A type epoxy resin (Japan Epoxy). Resin Co., Ltd. grade "834": epoxy equivalent 230-270). Except for these, a conductive adhesive was prepared in the same manner as in Example 1. A charging roller was prepared and evaluated in the same manner as in Example 38 except that these conductive adhesives were used.
<Example 42>
A conductive adhesive was prepared in the same manner as in Example 1 except that “carbon black” was not used in the conductive adhesive of Example 34. A charging roller was prepared and evaluated in the same manner as in Example 34 except that this conductive adhesive was used.
<Examples 43 to 45>
In the conductive adhesive of Example 42, “NBR”, “Resol type phenol resin” or “NBR” and “Resol type phenol resin” were not used, and the epoxy resin was bisphenol A type epoxy resin (Japan) Epoxy resin, grade “834”: epoxy equivalent 230-270). Except for these, a conductive adhesive was prepared in the same manner as in Example 1. A charging roller was prepared and evaluated in the same manner as in Example 42 except that these conductive adhesives were used.
<Comparative Examples 1-3>
A conductive adhesive was prepared in the same manner as in Example 1 except that “zinc stearate”, “trinonylphenyl phosphite” or “bisphenol A type epoxy resin” was not used in the conductive adhesive of Example 1. did. A charging roller was prepared and evaluated in the same manner as in Example 1 except that these conductive adhesives were used.

  The evaluation results of Examples 1 to 45 and Comparative Examples 1 to 3 are shown in Tables 5 and 6 below.

101: Conductive support shaft 102: Conductive adhesive layer 103: Conductive elastic layer 104: Surface layer

Claims (5)

A conductive support shaft whose surface is made of metal;
A conductive adhesive layer provided on the peripheral surface;
A charging roller having a conductive elastic layer having a rubber containing a halogen atom provided on the conductive adhesive layer,
The charging roller, wherein the conductive adhesive layer contains an epoxy resin, a fatty acid metal salt, and a phosphite.   The charging roller according to claim 1, wherein the fatty acid metal salt is a salt of at least one fatty acid selected from the group consisting of butyric acid, 2-ethylhexoic acid, lauric acid, stearic acid, ricinoleic acid, naphthenic acid, and montanic acid.   3. The charging roller according to claim 1, wherein the metal constituting the fatty acid metal salt is at least one selected from the group consisting of lithium, magnesium, calcium, strontium, barium, zinc, and tin.   An electrophotographic apparatus comprising the charging roller according to claim 1 and an electrophotographic photosensitive member.   A process cartridge comprising the charging roller according to any one of claims 1 to 3 and an electrophotographic photosensitive member, wherein the process cartridge is detachable from a main body of the electrophotographic apparatus.

Images