JP2005316081A - Electrically conductive roller for electrophotographic apparatus, process cartridge and the electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrically conductive roller, having low hardness and proper elastic characteristics, superior in image properties, even when it is allowed to be left standing in a severe environment over a prolonged period of time, and giving high quality images in various environments, from low temperature/low humidity environment to high temperature/high humidity environment, and to provide a process cartridge which uses the same and an electrophotographic apparatus. <P>SOLUTION: The electrically conductive roller for an electrophotographic apparatus comprises a shaft core body and a roller layer formed on the outer periphery of the shaft core body, wherein a polymer, comprising a polyether component having a neopentylene oxide structural unit and a curing agent component, is contained in the roller layer. The process cartridge and the electrophotographic apparatus which use the same are also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a conductive roller used in an electrophotographic apparatus. Specifically, for an electrophotographic apparatus that does not cause image defects in a harsh environment, and that does not cause image defects even when operated continuously for a long time from a low temperature / low humidity to a high temperature / high humidity environment. The present invention relates to a conductive roller.

  In a printer using an electrophotographic system, a photosensitive member is uniformly charged by a charging roller, and an electrostatic latent image is formed by a laser or the like. Next, the developer in the developing container is uniformly applied on the developing roller with appropriate charges by the developer applying roller and the developer regulating member, and the developer is transferred (developed) at the contact portion between the photosensitive member and the developing roller. Done. Thereafter, the developer on the photoconductor is transferred onto a recording sheet by a transfer roller and fixed by heat and pressure. The developer remaining on the photoconductor is removed by a cleaning blade, and a series of processes is completed.

  In an electrophotographic apparatus, for example, in the case of a developing roller, it is always in pressure contact with the photosensitive member and the developer regulating member, and is in contact with the photosensitive member and developer regulating member for a long time when stopped or not in use. Needs to be easily deformed and not damage the abutting member. Similarly, the charging roller and the transfer roller are also placed in an environment where they are always pressed against the photosensitive member. Even in the toner supply member and the cleaning member, the state in which the toner supply member and the cleaning member are always in pressure contact may continue for a long time. For this reason, the constituent members that contact the photosensitive member, the developer regulating member, the developing member, etc. are coated with a material made of an elastic body having a low hardness for the purpose of not damaging the mating member.

  As the polymer elastic material forming these constituent members, polymer elastomers and polymer foams having rubber elasticity are used, and these have low hardness and do not contaminate the image carrier or the transfer member. In addition, it is required to have a property of not being fused with a developer such as toner. Here, as materials constituting the polymer elastomer and polymer foam, solid rubber vulcanizates such as isoprene rubber, ethylene propylene rubber, silicone rubber, epichlorohydrin rubber, acrylonitrile butadiene rubber, and liquid raw materials such as polyol are used. Polyurethanes cured with isocyanate are used. The image forming apparatus member made of these materials may be required to have conductivity. For example, by mixing a conductive material such as carbon black or a metal oxide or adding an electrolyte, It is adjusted to the electrical resistance value. Among these, the conductivity can be imparted by both a conductive material and an electrolyte, and there is an advantage that these materials can be used by dissolving in a liquid raw material, and if necessary, a foam can be formed. Polyurethane produced using polyisocyanate as a main raw material is generally used. Among them, polypropylene glycol and polytetramethylene ether glycol having a low number of functional groups have been widely used as polyol raw materials for elastic members having low hardness.

  As a conventional technique, there is a technique for explaining a change in mechanical characteristics (compression set characteristics and creep characteristics) due to changes in temperature and relative humidity. For blade materials, by selecting polytetramethylene ether glycol, appropriate diisocyanate, and appropriate cross-linking agent, mechanical properties that are more stable against fluctuations in temperature and relative humidity compared to conventional polyester polyurethane blades. It is said that a blade having a response and good wear and compression set characteristics is provided (see Patent Document 1).

  By using polytetramethylene ether glycol or other hydrophobic polyol in the material of the developing roller, a urethane resin having a water absorption of 3% or less can be obtained, and by using it as an elastic body or skin material, It can have good adhesion at low hardness. Furthermore, it is said that it is possible to provide a developing roller capable of obtaining a high-quality image without uneven density and fog in a wide environment from low temperature and low humidity to high temperature and high humidity without causing any inconvenience that contaminates the photoreceptor (Patent Document). 2).

In recent years, the required performance of elastic members used in electrophotographic apparatuses has become more advanced as the speed of electrophotographic apparatuses increases and the quality of image quality increases. In addition to the mechanical properties (deformation recovery properties and elastic properties) in this environment, there is a further demand for improvement in uniform conductivity required for high resolution and durability required for higher speed. It is not always easy to realize these required performances only by a conventionally known method.
Japanese Patent Laid-Open No. 05-210342 Japanese Patent Laid-Open No. 07-199645

  The present invention solves the above-mentioned problems, and an object of the present invention is to have good elasticity characteristics with low hardness, excellent image characteristics even when left in a harsh environment for a long time, and low temperature / low humidity environment. It is an object of the present invention to provide a conductive roller for an electrophotographic apparatus capable of obtaining a high-quality image in a wide environment from high temperature to high temperature / high humidity environment, a process cartridge and an electrophotographic apparatus using the conductive roller.

  The present invention relates to a conductive roller for an electrophotographic apparatus having a shaft core and a roller layer formed on the outer periphery of the shaft core, wherein the roller layer includes a polypentylene oxide structural unit. An electroconductive roller for an electrophotographic apparatus comprising a polymer having an ether component and a curing agent component.

  In addition, a process cartridge and an electrophotographic apparatus using the electroconductive roller for the electrophotographic apparatus.

  According to the present invention, low hardness and good elastic properties, excellent image characteristics even when left in a harsh environment for a long time, and high-quality images can be obtained in a wide environment from low temperature and low humidity to high temperature and high humidity. The electroconductive roller for an electrophotographic apparatus and a process cartridge and an electrophotographic apparatus using the same can be obtained.

  Hereinafter, the present invention will be described in detail.

  The conductive roller of the present invention comprises a shaft core and a roller layer formed on the outer periphery of the shaft core, and a polyether component having a neopentylene oxide structural unit in the roller layer And a curing agent component.

  The neopentylene oxide structural unit present in the polyether component is represented by the following formula (1).

  In the present invention, the neopentylene oxide structural unit is preferably contained in an amount of 10 mol% or more, more preferably 20 mol% or more of the structural unit in the polyether component, in order to exhibit the effects of the invention.

  The polyether component preferably further has an alkylene oxide structural unit (excluding a neopentylene oxide structural unit). The alkylene oxide structural unit (excluding the neopentylene oxide structural unit) is represented by the following formula (2), and R represents an alkylene group (excluding the neopentylene group). R preferably has 2 to 4 carbon atoms. R may be linear or branched. Typical examples include an ethylene oxide structural unit, a propylene oxide structural unit, and a tetramethylene oxide structural unit.

  Moreover, as said alkylene oxide structural unit (except a neopentylene oxide structural unit), it is more preferable that a tetramethylene oxide structural unit is included. The tetramethylene oxide structural unit is represented by the following formula (3).

  Such a polyether component can contain arbitrary structural units in addition to the above structural units to the extent that the effects of the present invention are not impaired.

  As a molecular weight of a polyether component, 500-6000 are preferable at a number average molecular weight, and 1000-3000 are more preferable.

  When the polyether component has two or more structural units, the arrangement of the structural units is not limited and may be in the form of a random copolymer or a block copolymer. In either case, excellent elastic characteristics and low temperature characteristics can be obtained.

  It is preferable that content of such a polyether component is 25-90 mass% with respect to the whole resin component which comprises a layer.

  In the present invention, as a curing agent component for curing the polyether component to form a polymer, a curing agent component that becomes a target polymer can be appropriately selected and used. For example, an isocyanate compound, an amino resin compound, an epoxy resin compound, etc. can be used. In the present invention, it is preferable to use an isocyanate compound as the curing agent component because an elastic body having a low hardness is preferable as the polymer to be obtained. In this case, polyurethane is formed as the polymer. Hereinafter, the case where an isocyanate compound is used as the curing agent component will be described in detail.

  The isocyanate compound is not particularly limited, and any known compound can be used. For example, hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), phenylene diisocyanate (PPDI), xylene diisocyanate (XDI), naphthalene diisocyanate (NDI), and modified products thereof can be used. In particular, hexamethylene diisocyanate, isophorone diisocyanate, and toluene diisocyanate are suitable for the purpose of forming a low-hardness elastic body, and modified products thereof (particularly urethane-modified products, allophanate-modified products, biuret-modified products, and isocyanurate-modified products). Is also preferred. It is also possible to use mixtures of these.

  There is no restriction | limiting in particular as another component which can be used for polyurethane formation, It can be used in the range which does not impair the mechanical characteristic of the polyurethane obtained. As chain extenders, reactive unimolecular diols (ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, etc.) and diamines (ethylenediamine, hexamethylenediamine, diethyltoluenediamine, etc.) It can be used as appropriate. Moreover, it is also possible to use suitably polyfunctional crosslinking agents, such as a triol, a tetraol, and a polyamine, as a crosslinking agent.

  Furthermore, if necessary, a polyurethane foam can be formed by adding a catalyst, a foaming agent, a foam stabilizer, and the like and reacting them according to a conventional method.

  The conductive roller of the present invention has a shaft core and a roller layer formed on the outer periphery of the shaft core. The roller layer may be composed of a single layer or may have a multi-layer structure of two or more layers. In the case where the roller layer has a multi-layer structure, it is sufficient that at least one layer thereof is contained in an amount that achieves the intended effect of the polymer. About the layer which does not contain said polymer, it has the physical property, film thickness, etc. which do not impair the effect by making said layer contain said polymer, maintaining the objective and effect which form the layer. It is formed.

  The layer containing the polymer includes a material imparting conductivity as described later, and the content of the polymer in the layer is 60 to 99% by mass. preferable. In addition, for example, polymers such as polyester, acrylic resin, and silicone resin can be used in combination.

  FIG. 1 shows a schematic sectional view of an example of the structure of the conductive roller. In this example, the roller layer is composed of one layer. The conductive roller 1 has a shaft core 11 made of a conductive material such as metal as a shaft core at the center, and an elastic body layer 12 is laminated on the outer peripheral surface of the shaft core 11 as a roller layer. It has a structure. In the case of such a conductive roller, in the present invention, the elastic body layer 12 can include a polymer having a polyether component having a neopentylene oxide structural unit and a curing agent component.

  Examples of the material for the shaft core include metals such as iron, copper, aluminum, stainless steel, titanium, and nickel, metal alloys, and conductive resins. Alloys based on iron are preferred. The outer diameter of the shaft core is usually 4 to 8 mm. The surface of the shaft core body may be subjected to metal plating or the like.

  As a conductive agent added for the purpose of imparting conductivity to the elastic layer, a compound having ionic conductivity, such as an organic metal salt, can be appropriately used as necessary.

  In addition, various conductive metals or alloys such as carbon black, graphite, aluminum, copper, tin, stainless steel; tin oxide, zinc oxide, indium oxide, titanium oxide, tin oxide-antimony oxide solid solution, tin oxide-indium oxide solid solution, etc. Various conductive metal oxides; fine powders such as insulating substances coated with these conductive materials can be used. Among these, carbon black can be suitably used because it is relatively easily available and good chargeability is obtained. As means for dispersing the fine powdered conductive agent, conventionally used means such as a roll kneader, a Banbury mixer, a ball mill, a sand grinder, a paint shaker, etc. may be used as appropriate.

In addition, as a means for imparting conductivity to the elastic layer, a method of adding a conductive polymer compound instead of the conductive agent or together with the conductive agent can be used. For example, as a conductive polymer compound, as a host polymer, polyacetylene, poly (p-phenylene), polypyrrole, polythiophenine, poly (p-phenylene oxide), poly (p-phenylene sulfide), poly (p-ferene vinylene) ), Poly (2,6-dimethylphenylene oxide), poly (bisphenol A carbonate), polyvinylcarbazole, polydiacetylene, poly (N-methyl-4-vinylpyridine), polyaniline, polyquinoline, poly (phenylene ether sulfone), etc. These are used as dopants, such as AsF ₅ , I ₂ , Br ₂ , SO ₃ , Na, K, ClO ₄ , FeCl ₃ , F, Cl, Br, I, Kr, and other ions, Li, TCNQ (7 , 7,8,8-tetracyanoquinodimethane) Thing is, it is possible to use.

  The amount of the component imparting conductivity can be appropriately selected as necessary to achieve the desired properties of the conductive roller.

  The Asker-C hardness of the elastic layer is preferably 30 to 90 °. The Asker-C hardness is determined according to a rubber material hardness measurement method. Specifically, an Asker rubber hardness tester (high hardness) is used by using a test piece separately prepared in accordance with the standard standard Asker C-type SRIS (Japan Rubber Association Standard) 0101. This is defined as Asker-C hardness measured by Molecular Instruments Co., Ltd.).

  At the same time, the compression set of the elastic layer is preferably in the range of 0.5 to 5.0%. More preferably, it is 0.5 to 3.0% of range. The compression set is defined as a value measured according to the JIS K-6262 vulcanized rubber test method (compression set test).

  In order to ensure a uniform nip width when abutting and in addition to satisfy suitable setting properties, the thickness of the elastic layer should be selected in the range of 1 to 4 mm. Is more desirable. The thickness of the elastic layer is appropriately selected according to the hardness in order to achieve the target nip width.

The resistance value of the conductive roller of the present invention having one roller layer is preferably 10 ⁴ to 10 ¹⁰ Ω. The resistance value is defined as a resistance value when a conductive roller is pressed against a cylindrical metal roller (Φ60) with a constant pressure load of 500 g on one side and a DC voltage of 100 V is applied.

  FIG. 2 shows a schematic sectional view of another example of the structure of the conductive roller. In this example, the roller layer forms a two-layer structure. The conductive roller 1 has a shaft core 11 made of a conductive material such as a metal as a shaft core at the center, and an elastic body layer (base layer) 12 on the outer peripheral surface of the shaft core 11 as a roller layer. Further, a coating layer (surface layer) 13 is laminated on the outer peripheral surface of the elastic body layer 12. In the case of such a conductive roller, in the present invention, at least one of the elastic body layer and the coating layer only needs to contain a polymer having a polyether component having a neopentylene oxide structural unit and a curing agent component. . In particular, it is preferable that the above-mentioned polymer is included in the coating layer which is the surface layer. Details will be described below.

  In this case, the elastic body layer 12 serving as a base layer has flexibility, and can be formed as a molded body using rubber as a raw material main component. The raw material rubber of the elastic layer 12 is not particularly limited, and rubber satisfying predetermined mechanical properties can be used. For example, polymer elastomers having rubber elasticity such as solid rubber vulcanizates such as isoprene rubber, ethylene propylene rubber, silicone rubber, epichlorohydrin rubber, acrylonitrile butadiene rubber, and polyurethane obtained by curing a liquid raw material such as polyol with isocyanate. Alternatively, polymer foam can be used. A necessary amount of a conductive agent as described above is added to these materials.

  The Asker-C hardness of the elastic layer is preferably in the range of 15 to 55 °. More preferably, it is the range of 20-40 degrees.

  At the same time, the compression set of the elastic layer is preferably in the range of 0.5 to 5.0%. More preferably, it is 0.5 to 3.0% of range.

  The thickness of the elastic layer is more preferably selected in the range of 1.0 to 5.0 mm. The thickness of the elastic layer is appropriately selected according to the hardness in order to achieve the target nip width.

  As a material for forming the coating layer as the surface layer, the roller layer described above may have the same configuration as the elastic layer in a single conductive roller. In addition, components necessary for the function required for the coating layer itself according to the application, for example, a conductive agent, a non-conductive filler, etc., and various additive components used when forming a coating film body, for example, In addition, various additives such as a catalyst and a dispersion accelerator can be appropriately blended in the main coating material. Note that additives such as a conductive agent and a non-conductive filler can be appropriately selected from those exemplified above as additives that can be contained in the elastic layer according to the coating material of the main component. Moreover, the addition amount can be suitably selected according to the addition purpose, as long as the characteristics of the coating layer to be formed are maintained within the range where the effects of the present invention are exhibited.

  The thickness of the coating layer is preferably 1 μm or more in order to ensure sufficient wear resistance and to uniformly apply and form the coating layer. On the other hand, in order to realize uniform conductivity and to maintain the deformability of the entire conductive roller, the thickness is preferably 100 μm or less. The thickness of the coating layer may be appropriately selected in consideration of its hardness and the like.

  For forming the coating layer, a method of applying the raw material for forming the coating layer as a liquid to the surface of the elastic layer can be used. The method of applying the raw material for forming the coating layer is not particularly limited, but it is preferable to apply uniformly to the surface of the elastic layer by a method such as air spray, roll coating, curtain coating, or dipping. Thereafter, heat treatment may be performed as necessary.

The resistance value of the conductive roller of the present invention having two roller layers is preferably 10 ⁴ to 10 ¹⁰ Ω.

  The conductive roller as described above can be used as various rollers (charging roller, developing roller, etc.) of the electrophotographic apparatus. It can also be used as various rollers for process cartridges that can be attached to and detached from the electrophotographic apparatus.

  An example of the configuration of the electrophotographic apparatus is shown in FIG. In the electrophotographic apparatus of FIG. 3, the developing roller 25 is provided in contact with the photoreceptor 21 and the developer supply roller 26. The developing material 28 put in the developing container 34 of the developing device 24 is supplied to the developing roller 25 by the developing material supply roller 26. At this time, the amount is adjusted by the developer regulating member 27. On the other hand, an image is formed by the laser beam 23 on the photosensitive member 21 charged by the charging roller 22, and the developing material adheres from the developing roller 25. Thereafter, the paper 33 passes between the photoreceptor 21 and the transfer roller 29 so that the developer is transferred to the paper, and the developer is fixed on the paper by the fixing roller 32. The developer remaining on the photoreceptor 21 is scraped off by the cleaning blade 30 and dropped into the waste toner container 31.

  The process cartridge is configured by collecting predetermined parts in a cartridge form, and is detachable from the electrophotographic apparatus. For example, the apparatus includes a charging roller 22, a cleaning blade 30, a waste toner container 31 and / or a photoreceptor 21, a developing roller 25, a developer supply roller 26, a developer regulating member 27, a developer 28 and a developer container 34. And what to do.

  Hereinafter, the present invention will be described more specifically with reference to examples. These examples are examples of the best mode of the present invention, but the present invention is not limited to the examples. The conductive roller produced by the method shown in the embodiment can be suitably used as a roller used in an electrophotographic apparatus.

  In the specific examples described below, commercially available high-purity products were used as reagents used in the respective examples unless otherwise specified. Tables 1 and 2 show the polyol component and the isocyanate compound used in the production of the conductive roller constituting material in each example and comparative example.

<Example of single-layer conductive roller>
Example 1
A shaft roller made of SUM (outer diameter φ6 mm) was used as the shaft core, and a conductive roller was formed in which only an elastic layer provided with conductivity was formed as the roller layer. As a conductive agent, an ionic conductive agent (LiTFSI (trade name): manufactured by Morita Chemical Co., Ltd.) and carbon black (MA-100 (trade name): manufactured by Mitsubishi Chemical Corporation) are appropriately added, and this conductive roller is brought into contact with the conductive roller. The addition amount of the conductive agent was adjusted so that the electrical resistance was 10 ⁶ Ω and the Asker-C hardness of the elastic layer was 90 °.

  As a polyether component, an ionic conductive agent was added to a weighed 100 parts by mass of a copolymer glycol having a molecular weight of 1800 and a hydroxyl value of 61 (PTXG1800 (trade name): manufactured by Asahi Kasei Corporation, the structural formula is the following formula (4)). .7 parts by mass was added and vacuum degassing was performed at 80 ° C. for 1 hour to perform dehydration. Next, 25 parts by mass of an isocyanate compound (TDI, Coronate T-100 (trade name): manufactured by Nippon Polyurethane Industry Co., Ltd.) was mixed and reacted at 80 ° C. for 3 hours in a nitrogen atmosphere to obtain a free isocyanate concentration (hereinafter referred to as “free isocyanate”). A 5.9% urethane prepolymer was obtained (abbreviated as NCO%).

  Next, the urethane prepolymer was vacuum degassed at 80 ° C. for 1 hour, and after dehydration, 100 parts by mass of the urethane prepolymer was weighed, and 4 parts by mass of 1,4-butanediol and 2 parts by mass of trimethylolpropane was added and mixed with stirring. A core metal to be a shaft core was set in a metal mold, and the above mixture was poured into a metal mold preheated to 90 ° C., followed by curing reaction at 140 ° C. for 1 hour. Then, after removing the mold and performing secondary curing at 110 ° C. for 6 hours, the surface was polished to adjust the surface roughness Rz to 10 to 15 μm, and the outer surface where the urethane elastomer was formed on the outer peripheral surface of the shaft core body. A conductive roller having a diameter of 10 mm was obtained.

(Example 2)
In place of 100 parts by mass of the copolymer glycol used in forming the urethane prepolymer in Example 1, 50 parts by mass of the copolymer glycol, polytetramethylene ether glycol (L-2000 (product of molecular weight 2000), hydroxyl value 55 Name): manufactured by Hodogaya Chemical Co., Ltd., excluding neopentylene oxide structural unit) and weighing 50 parts by mass, the same procedure as in Example 1 was used, and NCO% was 6.1%. A urethane prepolymer was obtained.

  An elastic layer was formed in the same manner as in Example 1 except that this urethane prepolymer was used to obtain a conductive roller having an outer diameter of 10 mm.

(Example 3)
In place of 100 parts by mass of the copolymerized glycol used in forming the urethane prepolymer in Example 1, 50 parts by mass of the copolymerized glycol, polypropylene glycol having a molecular weight of 2000 and a hydroxyl value of 55 (ED56 (trade name): Takeda Mitsui) A urethane prepolymer having an NCO% of 6.1% was obtained in the same manner as in Example 1, except that 50 parts by mass of Neopentylene oxide structural unit manufactured by Chemical Co., Ltd. was used. .

  An elastic layer was formed in the same manner as in Example 1 except that this urethane prepolymer was used to obtain a conductive roller having an outer diameter of 10 mm.

(Comparative Example 1)
Instead of the copolymer glycol used in forming the urethane prepolymer in Example 1, a polytetramethylene ether glycol having a molecular weight of 2000 and a hydroxyl value of 55 (L-2000 (trade name): manufactured by Hodogaya Chemical Co., Ltd.) was used. In the same manner as in Example 1, a urethane prepolymer having an NCO% of 6.3% was obtained.

  An elastic layer was formed in the same manner as in Example 1 except that this urethane prepolymer was used to obtain a conductive roller having an outer diameter of 10 mm.

(Comparative Example 2)
Example 1 is the same as Example 1 except that polypropylene glycol having a molecular weight of 2000 and a hydroxyl value of 55 (ED56 (trade name): manufactured by Mitsui Takeda Chemical Co., Ltd.) is used instead of the copolymer glycol used in forming the urethane prepolymer. By this method, a urethane prepolymer having an NCO% of 6.3% was obtained.

  An elastic layer was formed in the same manner as in Example 1 except that this urethane prepolymer was used to obtain a conductive roller having an outer diameter of 10 mm.

<Example of multilayer (two-layer) conductive roller>
Example 4
As the roller layer, a conductive roller was formed in which an elastic layer and a coating layer each imparting conductivity were formed. As a conductive agent, carbon black (MA-100 (trade name): manufactured by Mitsubishi Chemical Co., Ltd.) is added as appropriate so that the electric resistance when contacting the conductive roller is 10 ⁵ to 10 ⁶ Ω. The addition amount of the agent was adjusted.

  As the shaft core body, nickel plating is applied to the surface of the SUM core metal (outer diameter φ8mm), and an adhesive (silane coupling agent, manufactured by Toray Dow Corning) is applied to the outer peripheral surface and baked. What was done was used. This shaft core was placed in a mold, and liquid silicone rubber 1 (made by Toray Dow Corning Silicone) was injected into a cavity formed in the mold. Subsequently, the mold was heated, and the injected silicone rubber was cured by heating at 150 ° C. for 30 minutes. After cooling, the mold was removed, and a heat treatment was performed at 150 ° C. for 30 minutes to provide an elastic body layer having a thickness of 4 mm on the outer peripheral surface of the shaft core body. The obtained elastic layer had an Asker-C hardness of 32 ° and a compression set of 1.9%.

  On the other hand, 6.8 parts by mass of 1,4-butanediol and 1 part by mass of trimethylolpropane were added to 100 parts by mass of copolymer glycol (PTXG1000 (trade name): molecular weight 1000: manufactured by Asahi Kasei Co., Ltd.), and further an isocyanate compound. (Coronate T-100 (trade name): manufactured by Nippon Polyurethane Industry Co., Ltd.) After mixing and stirring, 15 parts by mass, a prepolymer type polyol having a molecular weight of 13,000 and a hydroxyl value of 40 was obtained.

  71.2 parts by mass of an isocyanate compound (urethane-modified MDI, Samprene P-665 (trade name): manufactured by Sanyo Chemical Industries, Ltd.) is added to the prepolymer type polyol, and the value of [NCO] / [OH] is 1. .2 An organic solvent (methyl ethyl ketone) is added to the above raw material mixture to adjust the solid content to 20% by mass, and 15 parts by mass of PMMA resin particles (φ15 μm) are added and uniformly dispersed and mixed for coating layer formation A raw material liquid was prepared.

  The shaft core body after the formation of the elastic body layer was immersed in the raw material liquid for forming the coating layer to coat the outer surface of the elastic body layer, and then pulled up and naturally dried. Subsequently, the coated raw material for forming the coating layer is cured by heating at 140 ° C. for 60 minutes, and the coating layer is formed into an elastic body so as to have a thickness of 20 μm and a surface roughness (Rz) of 6 to 9 μm. A conductive roller having an outer diameter of 16 mm was obtained by laminating on the outer peripheral surface of the layer.

(Example 5)
Instead of 100 parts by weight of the copolymerized glycol used in forming the prepolymer type polyol in Example 4, 50 parts by weight of the copolymerized glycol and tetramethylene glycol (PTG1000SN (trade name): molecular weight 1000: manufactured by Hodogaya Chemical Co., Ltd.) A conductive roller was obtained in the same manner as in Example 4 except that a mixture with 50 parts by mass (not including neopentylene oxide structural unit) was used.

(Example 6)
Instead of 100 parts by weight of the copolymerized glycol used in forming the prepolymer type polyol in Example 4, 50 parts by weight of the copolymerized glycol and polypropylene glycol (Diol-1000 (trade name): molecular weight 1000: Mitsui Takeda Chemical Co., Ltd.) A conductive roller was obtained in the same manner as in Example 4 except that a mixture with 50 parts by mass) (excluding manufactured neopentylene oxide structural unit) was used.

(Comparative Example 3)
Example 4 except that tetramethylene glycol (PTG1000SN (trade name): molecular weight 1000: manufactured by Hodogaya Chemical Co., Ltd.) was used instead of the copolymerized glycol used in forming the prepolymer type polyol in Example 4. A conductive roller was obtained by the same method.

(Comparative Example 4)
Example 4 except that polypropylene glycol (Diol-1000 (trade name): molecular weight 1000: manufactured by Mitsui Takeda Chemical Co., Ltd.) was used in place of the copolymerized glycol used in the formation of the prepolymer type polyol in Example 4. A conductive roller was obtained in the same manner as in No. 4.

(Comparative Example 5)
Instead of the copolymer glycol used in the formation of the prepolymer type polyol in Example 4, a polyester polyol (Nipporan 4002 (trade name): molecular weight 1000: manufactured by Nippon Polyurethane Industry Co., Ltd., excluding neopentylene oxide structural unit) was used. A conductive roller was obtained in the same manner as in Example 4 except that it was used.

<Evaluation of characteristics: single-layer conductive roller>
A process cartridge including a charging roller 22, a cleaning blade 30, a waste toner container 31, and a photoreceptor 21 as illustrated in FIG. 3, using the conductive roller manufactured in Examples 1 to 3 and Comparative Examples 1 and 2 as a charging roller. The cartridge was assembled into an electrophotographic apparatus as shown in FIG. 3 and evaluated as follows. Table 1 shows the evaluation results.

<Charge uniformity and ghost (image durability)>
Endurance for image output of 12,000 sheets in a high temperature / high humidity environment (30 ° C., 80% RH, abbreviation: H / H) and low temperature / low humidity environment (15 ° C., 10% RH, abbreviation: L / L) Image evaluation was performed after the test. The image was evaluated for the presence or absence of a ghost as a halftone image in which a square black portion of 25 mm square was arranged on the first rotation of the photoconductor from the start of writing, and one dot was printed with a comma pattern after the second rotation of the photoconductor. . Further, in the halftone part, the charging uniformity was evaluated by the presence / absence of spot-like and streak-like image defects. At this time, the image was output by adjusting the applied voltage in each environment so that the surface potential VD of the photoconductor was -400V.
◎: Image defect or ghost is not observed ○: Image defect or ghost is slightly observed but not affected Δ: Image defect or ghost is thinly observed and affects image ×: Image defect or ghost What is clearly seen and affects the image Examples 1 to 3 and Comparative Example 1 were at a level with no problem in the evaluation of charging uniformity in a high temperature / high humidity environment and a low temperature / low humidity environment. In Comparative Example 2, streaks were generated on the image in a high temperature / high humidity environment and appeared as image defects. In Examples 1 to 3, no ghost was generated in both environments, but in Comparative Examples 1 and 2, a ghost was observed in a low temperature / low humidity environment.

<Pressure contact marks>
After leaving the cartridge in a severe high temperature / high humidity environment (40 ° C., 95% RH, abbreviation: severe H / H) and a severe low temperature environment (−20 ° C., abbreviation: severe L) for 30 days, J / J environment (room temperature, normal humidity), left for one day, and then installed a cartridge in the printer body to evaluate the image.
◎: Press-contact marks are not visible on the image ○: Press-contact marks are very thin but do not affect the image △: Press-contact marks are thin and affect the image ×: The press-contact marks are clearly visible That affect the image (Severe high temperature / high humidity environment)
The press contact mark on the conductive roller produced in Example 1 was hardly seen on the image, and good results were obtained. The conductive rollers produced in Examples 2 and 3 and Comparative Examples 1 and 2 were confirmed to have a thin pressure contact mark on the image, but the level was not practically problematic.

(Severe low temperature environment)
The pressure contact trace on the elastic roller produced in Example 1 was hardly seen on the image, and good results were obtained. In the elastic rollers manufactured in Examples 2 and 3, the pressure contact trace was confirmed to be thin on the image, but it was at a level causing no practical problem. In Comparative Examples 1 and 2, the pressure contact trace was found on the image and was at a problem level. From the results, the goodness of the examples of the present invention appeared even in a severe low temperature environment.

<Comprehensive evaluation>
Based on the above evaluation results, a comprehensive performance evaluation was performed, and the following four categories were evaluated.
◎: Extremely good ○: Good △: Slightly difficult and problematic for practical use ×: Clear problem, not at a practical level When evaluated comprehensively, the conductive materials produced in Examples 1 to 3 The roller was evaluated as being good or better with no problems in practical use in any of the setting performance in a harsh environment and image characteristics in a high temperature / high humidity to low temperature / low humidity environment. Among them, the conductive roller produced in Example 1 was evaluated as extremely good.

* Numerical values in resin component are parts by mass. <Evaluation of characteristics: Multi-layer (2 layers) conductive roller>
The developing roller 25, the developer supply roller 26, the developer regulating member 27, the developer regulating member 27, the developer 28, and the developing container as shown in FIG. 34, and the cartridge was incorporated into an electrophotographic apparatus as shown in FIG. 3 and evaluated as follows. Table 2 shows the evaluation results.

<Pressure contact marks>
After leaving the cartridge in a severe high temperature / high humidity environment (40 ° C., 95% RH, abbreviation: severe H / H) and a severe low temperature environment (−20 ° C., abbreviation: severe L) for 30 days, J / J environment (room temperature, normal humidity), left for one day, and then installed a cartridge in the printer body to evaluate the image.
◎: Press-contact marks are not visible on the image ○: Press-contact marks are very thin but do not affect the image △: Press-contact marks are thin and affect the image ×: The press-contact marks are clearly visible That affect the image (Severe high temperature / high humidity environment)
In the conductive rollers prepared in Examples 4 to 6 and Comparative Examples 3 and 4, the image pressure contact mark was confirmed to be thin, but it was at a level that had no practical problem. In Comparative Example 5, pressure contact traces were observed and the image was problematic.

(Severe low temperature environment)
The press-contact marks on the conductive roller produced in Example 4 were hardly seen on the image, and good results were obtained. In the conductive rollers produced in Examples 5 and 6, the pressure contact trace was confirmed to be thin on the image, but it was at a level causing no practical problem. In Comparative Examples 3 and 4, the pressure contact trace was found on the image and was at a problem level. In Comparative Example 5, a particularly bad result was obtained. From the results, in the severe low temperature environment, the mechanical elasticity good in the examples of the present invention appeared.

<Image performance>
Continuous image formation was performed under high temperature / high humidity environment (30 ° C., 80% RH, abbreviation: H / H) and low temperature / low humidity environment (15 ° C., 10% RH, abbreviation: L / L). The presence or absence of a problem in the image was judged.
◎: Good with no problem on image ○: Slight shading or fogging is observed, but there is no problem with image △: Shading or fogging is confirmed, and problematic X: Clearly confirms shading and fogging What was done In the conductive rollers prepared in Examples 4 to 6 and Comparative Examples 3 to 5, in the image evaluation after 12k, a remarkable difference was observed between the examples and the comparative examples in the H / H environment. In Examples 4 and 5, the image quality was good, but in other cases, uneven shading occurred, and in Comparative Examples 4 and 5, the fog deteriorated and became a problem. In particular, Comparative Example 5 was in a very bad state.

<Comprehensive evaluation>
Based on the above evaluation results, a comprehensive performance evaluation was performed, and the following four categories were evaluated.
◎: Extremely good ○: Good △: Slightly difficult and problematic in practical use ×: Clear problem, not at a practical level When evaluated comprehensively, the conductive materials produced in Examples 4 to 6 The roller was evaluated as being good or better without any problem in practical use in any of the items of pressure contact marks in a harsh environment and images in the high temperature / high humidity to low temperature / low humidity environment (initial stage and after durability). Among them, the elastic roller produced in Example 4 was evaluated as extremely good overall.

* Numerical values in resin component are parts by mass.Note that the present invention is not limited to the conditions shown in the specific examples described above, and within the technical scope of the present invention, the embodiments are selected according to various applications. It can be implemented with changes.

It is a typical sectional view showing composition of a conductive roller which has one roller layer. It is a typical sectional view showing composition of a conductive roller which has two roller layers. It is a figure which shows the structure of an electrophotographic apparatus.

Explanation of symbols

1: Conductive roller 11: Shaft core (shaft core body)
12: Elastic layer (base layer)
13: Coating layer (surface layer)
21: Photoconductor 22: Charging roller 23: Laser beam 24: Developing device 25: Developing roller 26: Developing material supply roller 27: Developing material regulating member 28: Developing material 29: Transfer roller 30: Cleaning blade 31: Waste toner container 32 : Fixing roller 33: Paper 34: Developer container

Claims (6)

A conductive roller for an electrophotographic apparatus having a shaft core and a roller layer formed on the outer periphery of the shaft core, wherein the roller layer includes:
A conductive roller for an electrophotographic apparatus comprising a polymer having a polyether component having a neopentylene oxide structural unit and a curing agent component.   The electroconductive roller for an electrophotographic apparatus according to claim 1, wherein the polyether component further has an alkylene oxide structural unit (excluding a neopentylene oxide structural unit).   The electroconductive roller for an electrophotographic apparatus according to claim 2, comprising a tetramethylene oxide structural unit as the alkylene oxide structural unit (excluding the neopentylene oxide structural unit).   The electroconductive roller for an electrophotographic apparatus according to claim 1, wherein an isocyanate compound is used as the curing agent component.   A process cartridge using the electroconductive roller for an electrophotographic apparatus according to claim 1. An electrophotographic apparatus using the electroconductive roller for an electrophotographic apparatus according to claim 1.

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