JP2009058863A - Manufacturing method for electrophotographic member and electrophotographic member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an electrophotographic member, continuously removing foreign matter inhibiting performance from a coating liquid without generating bubbles by filtering the coating liquid using a vibrating filter and applying the filtered coating liquid to the outer periphery of a substrate, and having no coating defect and excellent performance. <P>SOLUTION: This manufacturing method for an electrophotographic member includes a process of forming a coating layer by applying a coating liquid at least to the outer periphery of a substrate, wherein the coating liquid passed through the vibrating filter is applied to the outer periphery of the substrate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing an electrophotographic member and an electrophotographic member.

  Conventionally, many methods are known as electrophotographic methods. In general, an electrostatic latent image is formed on a photoconductor using a photoconductive substance by various means, and then the electrostatic latent image is developed with a developer (toner) to obtain a visible image (toner image). To do. After the toner image is transferred to a transfer material such as paper, a print image can be obtained by fixing the toner image on the transfer material by heat, pressure or the like. In these electrophotographic methods, a member in which a coating layer is provided on a cylindrical substrate or an endless belt substrate is used. Specific examples include a developing roller, a photoreceptor, a charging roller, a transfer roller, and a fixing roller.

  These members are used for the purpose of obtaining high-quality print images by adjusting electrical resistance, imparting charge to toner, preventing toner adhesion, and forming uniform surface irregularities on a cylindrical substrate or endless belt substrate. A coating liquid in which various solid particles such as conductive particles such as metal particles, metal oxide particles or carbon-based particles, ceramic particles, resin particles, and solid lubricant particles are dispersed in a binder resin solution according to the purpose, Generally, a coating layer is formed by coating on the outer periphery of a substrate.

  For example, in the developing roller, a coating layer containing conductive particles and resin particles is formed on the outer periphery of the substrate for the purpose of forming uniform surface irregularities in order to optimize the charging of toner and to convey the toner. What has been proposed.

  Specifically, as an example of forming a coating layer on the developing roller, a resin coating layer containing conductive particles is formed on the outer periphery of the substrate in order to prevent overcharging (charge-up) of the toner Is disclosed (for example, see Patent Document 1).

  In general, as a method of forming the coating layer on the outer periphery of the substrate, various solids such as conductive particles such as metal particles, metal oxide particles or carbon particles, ceramic particles, resin particles, and solid lubricant particles are used depending on the purpose. There is a method in which a coating liquid in which particles are dispersed in a binder resin solution is formed by dipping, spraying, brushing, or the like.

  However, with recent improvements in image quality of electrophotography and speeding up of electrophotographic apparatuses, surface physical properties and durability required for electrophotographic members that have a great influence on image quality are becoming more advanced. For this reason, it is necessary to stably obtain performance capable of withstanding high image quality and high speed over a long period of time, and a coating layer formed more uniformly is required.

  In general, in a coating solution in which solid particles are dispersed in a binder resin solution, reaggregation of solid particles tends to occur over time.

  Further, when there is a dead space where the flow rate of the coating solution is not stable in the circulation path of the coating solution, reaggregation is likely to increase.

  Further, if there is a portion having an interface with a gas such as a coating solution reservoir, the binder resin is likely to be precipitated due to the action of stirring or evaporation of the solvent.

  For example, when a coating layer is formed using a coating solution to which solid particles having a large specific gravity difference or solid particles having high cohesiveness are added with a binder resin dissolved in a solvent, the coating solution composition is used in the conventional method. Problems such as local variation in volume resistance in the coating layer and non-uniform surface roughness of the coating layer occur due to sedimentation, separation, and aggregation of solid particles dispersed in the coating layer. In some cases, it is not possible to meet the advanced requirements for coating layers.

  In addition, when solid particles are dispersed and contained to form the desired surface irregularities in the coating layer, the distribution of the solid particles in the coating layer becomes non-uniform due to the occurrence of sedimentation or separation of the solid particles due to the difference in specific gravity. Problems such as protrusions and coating unevenness occur on the surface of the layer, and it is difficult to obtain a stable desired surface shape.

  On the production side, when performing multiple coatings in succession, it is difficult to maintain a uniform dispersion state of the solid particles in the coating solution for these reasons, and the surface roughness and electrical resistance value in the early and late stages of continuous production. There is a problem that variation such as the above becomes large.

In order to produce an electrophotographic member in which the surface coating layer has a desired surface shape and uniform dispersion of additive particles in the surface coating layer, the coating layer is applied by applying a coating solution irradiated with ultrasonic waves through a fluid medium. A forming method is disclosed (for example, refer to Patent Document 2).
Japanese Patent Laid-Open No. 3-200986 JP 2004-37598 A

  However, the dispersion of the reagglomerates of solid particles in the coating solution containing the binder resin and solid particles has been realized by irradiating with ultrasonic waves. It was difficult to remove the deposit (precipitate).

  The filter resin is clogged by the insoluble matter or gel (precipitate) and solid particles of the binder resin, the concentration of the solid particles in the coating solution changes with coating, and the surface roughness and resistance value fluctuate with the number of products produced. An electrophotographic member having no variation in surface roughness and electric resistance value could not be produced continuously.

  In addition, the method using ultrasonic waves has a problem in that a coating defect is likely to occur due to bubbles generated by ultrasonic irradiation and the production yield is lowered.

  In the present invention, by filtering the coating solution using a vibrating filter, foreign substances that impede the performance of the electrophotographic member can be removed from the coating solution, and this coating solution is applied to a substrate. Thus, an object of the present invention is to provide a production method capable of continuously producing an electrophotographic member having excellent performance free from coating defects due to bubbles.

  The present invention is achieved by adopting the following configuration.

1. An electrophotographic member manufacturing method comprising a step of forming a coating layer by applying a coating solution to at least the outer periphery of a substrate,
A method for producing an electrophotographic member, wherein the coating liquid that has passed through a vibrating filter is applied to the outer periphery of a substrate.

2. In the circulation path that passes the coating liquid through the coating operation unit,
2. The method for producing an electrophotographic member according to 1 above, wherein the electrophotographic member is passed through a vibrating filter.

  3. 3. The electron according to 1 or 2, wherein a vibration generation source for vibrating the filter has a vibration frequency of 10 to 5000 Hz, a vibration amplitude of 0.1 to 5 mm, and a vibration direction perpendicular to the filter surface. A method for producing a photographic member.

  4). An electrophotographic member produced by the method for producing an electrophotographic member according to any one of 1 to 3 above.

  The method for producing an electrophotographic member of the present invention can remove foreign matter that impedes the performance of the electrophotographic member from the coating solution by filtering the coating solution using a vibrating filter. By applying the coating solution to the substrate, there is an excellent effect that an electrophotographic member having excellent performance free from coating defects due to bubbles can be continuously produced.

  In the electrophotographic member according to the present invention, a coating layer is formed by applying a coating solution to the outer periphery of a substrate.

  The coating solution may contain an insoluble matter or precipitate of the binder resin, coarse particles or aggregates of solid particles, or other coarse foreign matters. When a coating layer is formed using a coating solution that contains insoluble matter or precipitates of binder resin, coarse particles or aggregates of solid particles, or other coarse foreign matters, the portions such as coarse particles and aggregates are coated. The film becomes defective, and when a printed image is formed, it becomes an image defect, which causes a practical problem.

  The method for producing an electrophotographic member of the present invention is characterized in that a coating layer is formed by applying a coating solution filtered using a vibrating filter to the outer periphery of a substrate.

  Technologies to re-dissolve insoluble matter and precipitates in the coating solution and to prevent clogging of the filter by loosening the aggregates of the solid particles include a method of filtering while irradiating ultrasonic waves and vibrating the filter. A technique of irradiating a sound wave to loosen agglomerates of solid particles and performing filter filtration is generally known.

  However, in the coating solution used for forming the coating layer of the electrophotographic member, after filtering with a known ultrasonic wave to vibrate the filter, or after irradiating the ultrasonic wave to loosen the solid particles, When the filter is filtered, bubbles are generated in the coating solution by ultrasonic cavitation, and coating defects due to the bubbles are generated, making it impossible to stably produce electrophotographic members.

  The present inventors can remove insoluble matters and precipitates of binder resin, aggregates of solid particles, and foreign matters from the coating solution used for forming an electrophotographic member, and there is no coating defect due to bubbles continuously. The manufacturing method which can manufacture the member for electrophotography was examined.

  As a result of examination, fine foreign substances can be removed by applying the coating solution filtered using a vibrating filter to the outer periphery of the substrate and drying to form a coating layer. It has been found that an electrophotographic member having no defect can be produced.

Specifically, the method for producing an electrophotographic member of the present invention has the following characteristics.
1. By vibrating the filter, the filter can be continuously filtered without clogging.
2. Since ultrasonic waves are not used, there is no generation of bubbles due to cavitation, and there are no coating defects due to bubbles.
3. Filter performance is improved by vibrating the filter, so it is possible to use a fine filter with an opening of about 1.5 times the particle size of the solid particles in the coating liquid, and even fine foreign substances can be removed. Become.
4). When the filter is vibrated, the insoluble matter and precipitates in the coating solution collide with the vibrating filter and are re-dissolved or loosened, and the precipitate and solid particles are filtered. It is possible to return it to the coating solution instead of removing it. As a result, it is possible to always apply using a coating solution having a uniform resin concentration and solid particle concentration.

  The electrophotographic member referred to in the present invention is a member provided with a coating layer on the outer periphery of a cylindrical or endless belt substrate used in an electrophotographic image forming apparatus. Specifically, a developing roller, a photoreceptor, Examples include a charging roller, a transfer roller, and a fixing roller.

  According to the present invention, it has been made possible to continuously produce electrophotographic members having little variation in surface roughness and electric resistance, no coating defects, and no problems in evaluation of practical tests.

  Taking the developing roller as an example, if the surface roughness varies, density unevenness occurs in the halftone image. Further, if there is a variation in the electric resistance value, image defects such as white spots and black spots occur in the halftone image. Further, if there is a coating defect, the location of the defect becomes an image defect such as a white spot or a black spot.

  Hereinafter, the present invention will be described in detail.

"filter"
As a filter used for filtration of a coating liquid, a surface filtration type filter that performs filtration by adhering and volume of foreign matters on a filter surface, and a depth filtration type filter that captures foreign matters by details inside a filter are known. However, when a filter of the depth filtration type is used, the insoluble matter, precipitate, and solid particles of the binder resin captured in the details inside the filter cannot move, and even if the filter is vibrated, it can be recovered from clogging. Since it is difficult, in the present invention, it is preferable to use a surface filtration type filter.

  The material of the filter is preferably a material that can easily transmit vibration, for example, a highly rigid metal or ceramic. Specifically, a rigid mesh manufactured by Nippon Pole Co., Ltd. or a Fuji plate manufactured by Fuji Filter Industry Co., Ltd. can be used.

<Filter vibration>
FIG. 1 is a schematic diagram illustrating an example of a state in which a coating liquid is filtered using a filter.

  In FIG. 1, 11 is a filter, 12 is solid particles, 13 is an aggregate of solid particles, 14 is an insoluble matter or precipitate of a binder resin, 21 is a flow direction of the coating liquid, and 31 is a vibration direction of the filter.

  1A shows a state in which the coating liquid is filtered without vibrating the filter, and FIG. 1B shows a state in which the coating liquid is filtered while vibrating the filter.

  In Fig. 1 (a) where the filter is not vibrated, the insoluble matter and precipitates of the binder resin and the aggregates of solid particles are clogged with the filter, but in Fig. 1 (b) where the filter is vibrated, the filter is bound. The resin insoluble matter, precipitate, and solid particle agglomerate collide with the filter and are re-dissolved or agglomerated to loosen and pass through the filter.

  The coating liquid filtered using the filter shown in FIG. 1B that vibrates the filter is free of binder resin insoluble matter and precipitates, and solid particle aggregates, and before filtration. It has the characteristic that the density | concentration of binder resin and the density | concentration of a solid particle do not change after filtration.

  In the present invention, it is preferable to use a filter device that vibrates the filter disk with the filter attached thereto by the vibration generator.

  In the present invention, it is preferable to vibrate the filter in a specific direction with a specific vibration frequency and a specific vibration amplitude within a range where bubbles are not generated by cavitation by the vibration generator.

  The vibration frequency of the vibration generator is preferably 10 to 5000 Hz. The vibration amplitude of the vibration generator is preferably 0.1 to 5 mm.

  As the vibration direction of the filter, it is preferable to vibrate in a direction perpendicular to the filter surface because filtration can be performed more efficiently.

  The vibration frequency, vibration amplitude, and vibration direction of the vibration generator can be measured with a known vibration measuring machine, laser displacement meter, or the like. For example, it can be measured by a CCD laser displacement meter “LK-G series” manufactured by Keyence.

  The vibration generator is not particularly limited, and specifically, a vibration generator using magnetism, a vibration generator using air, a vibration generator using a centering member, or the like can be used.

"filtration"
FIG. 2 is a schematic diagram showing an example of a manufacturing flow in which a coating liquid filtered by a vibrating filter is applied to the outer periphery of a substrate.

  In FIG. 2, 1 is a coating liquid storage tank, 2 is a liquid feed pump, 3 is a filtration device, 4 is a filter, 5 is a vibration generating device, 6 is a filter disk, and 7 is a coating operation unit according to the present invention. The apparatus, 8 is a substrate, 9 is a liquid feed pipe, 10 is a return pipe, and 11 is a coating liquid.

  The coating liquid 11 is fed to the filtering device 3 by the liquid feeding pump 2 and filtered while the filter 4 attached to the filter disk 6 is vibrated by the vibration generating device 5, and the filtered coating liquid passes through the liquid feeding pipe 9. The liquid is fed to the coating device 7 and the outer periphery of the substrate 8 is applied by the coating device. The coating liquid that has not been used for coating is returned to the coating liquid storage tank through the return pipe 10, stored in the coating liquid storage tank, and then returned again to the filter filtration device 1 by the liquid feed pump. As shown in FIG. 2, the coating liquid moves in the order of the coating liquid storage tank 1, the liquid feed pump 2, the filtration device 3, the coating device 7, the coating liquid storage tank 1, and is referred to in the present invention. A circulation path is formed.

  And the coating liquid 11 is sent to the coating device 7 after being filtered by the vibrating filter 4, and used for coating.

  As the coating device, a type that circulates the coating liquid is preferable, and an overflow dip coating device, a spray coating device, a CSH coating device, or the like can be used.

  The CSH coating device is a slide hopper type coating device which is a kind of a circular amount regulating type coating device. The CSH coating apparatus is described in detail in JP-A-58-189061, Japanese Patent Application No. 7-128023, and Japanese Patent Application No. 7-162021.

  Hereinafter, a developing roller will be taken as an example of an electrophotographic member, and a manufacturing method thereof will be described in detail.

<Preparation of coating solution>
First, the process for preparing the coating solution will be described.

  The coating solution may be prepared by dissolving and mixing a binder resin, solid particles, and optionally a conductive agent (for example, an electronic conductive agent or an ionic conductive agent) with a dissolution and mixing device, and then dispersing the solid particles with a dispersion device. it can.

  It does not specifically limit as a dissolution mixing apparatus, It is preferable to use the dissolution mixing apparatus which has a heating and stirring apparatus.

  The dispersing device is not particularly limited as long as it can disperse solid particles, and a known dispersing device can be used.

<Binder resin>
The binder resin used for forming the coating layer is not particularly limited. Specifically, urea resin, melamine resin, alkyd resin, phenol-modified / silicone-modified modified alkyd resin, oil-free alkyd resin, etc. Acrylic resin, silicone resin, fluororesin, phenol resin, polyamide resin, epoxy resin, polyester resin, maleic acid resin, urethane resin and the like can be mentioned. Of these, urethane resin, polyamide resin, acrylic resin, and the like are preferably used from the viewpoints of film strength, abrasion resistance, toner chargeability, and the like. Among these, it is particularly preferable to use a urethane resin from the viewpoint of obtaining good wear resistance.

  Examples of the urethane resin include those obtained by reacting a urethane raw material containing a polyhydroxy compound and an isocyanate compound, for example, those obtained by a method in which a prepolymer is subjected to a crosslinking reaction, and polyols obtained by polyisocyanate by a one-shot method. What was obtained by the method of making it react with soot is mentioned.

  In this case, as a polyhydroxyl compound used when obtaining a urethane resin, a polyol used for production of a general flexible polyurethane foam or a urethane elastomer, for example, a polyether polyol having a polyhydroxyl group at a terminal, a polyester polyol, or a polyether In addition to polyester polyols, general polyols such as polyolefin polyols such as polybutadiene polyol and polyisoprene polyol, and so-called polymer polyols obtained by polymerizing ethylenically unsaturated monomers in polyols can be used. As the isocyanate compound, polyisocyanate used in the production of general flexible polyurethane foam and urethane elastomer, that is, tolylene diisocyanate (sometimes referred to as TDI), crude TDI, 4,4′-diphenylmethane. Diisocyanate (sometimes referred to as MDI), crude MDI, aliphatic polyisocyanate having 2 to 18 carbon atoms, alicyclic polyisocyanate having 4 to 15 carbon atoms, and mixtures and modified products of these polyisocyanates, such as partially polyol A prepolymer obtained by reacting with a polymer can be used. In particular, the mixing ratio of the polyisocyanate may be lowered for the purpose of reducing the universal hardness of the coating layer.

  The urethane resin may be prepared using a one-component or two-component urethane raw material containing a polyhydroxyl compound and a polyisocyanate, and an epoxy resin or a melamine resin is used as a cross-linking agent as necessary. Also good.

  Polyamide resins include nylon 6,6,6,6,10,6,12,11,12,12,12, and polyamides obtained from polycondensation between different types of polyamide monomers. Alcohol-soluble ones are preferred. For example, those obtained by adjusting the molecular weight of a polyamide terpolymer or quaternary copolymer, or those obtained by methoxymethylating nylon 6 or nylon 12 to be soluble in alcohol or water.

  Examples of the acrylic resin include polyacrylate, polymethyl methacrylate, polymethyl ethacrylate, those obtained by substituting these side chain ends with a hydroxyalkyl group, and copolymers thereof.

<Solid particles>
The solid particles are added for the purpose of forming irregularities on the surface of the developing roller and leak start points.

The particle diameter of the solid particles is preferably 5 to 40 μm, more preferably 7 to 30 μm in terms of the median diameter (D ₅₀ ) on a volume basis.

The solid particles preferably have a volume resistance of 10 ¹⁵ Ω · cm or more and do not dissolve in the coating solution used for forming the coating layer but are well dispersed in the coating solution.

  Examples of the solid particles include inorganic particles and resin particles.

  Specific examples of the inorganic particles include silica, titania, and alumina.

  Particularly preferred are resin particles.

  Specific examples of the resin particles include crosslinked acrylic resin particles, polyamide resin particles such as nylon 6, polyolefin resin particles such as polyethylene and polypropylene, silicone resin particles, phenol resin particles, polyurethane resin particles, and styrene resins. Examples thereof include resin particles and benzoguanamine particles.

  Among these, crosslinked acrylic resin particles are preferably used. Further, the solid particles are preferably those whose surfaces are treated with a silane coupling agent.

  5-40 mass% is preferable and, as for the quantity of the solid particle contained in a coating layer, 10-30 mass% is more preferable.

The volume-based median diameter (D ₅₀ ) of solid particles can be measured and calculated using a device in which a data processing computer system (Coulter) is connected to “Multisizer 3” (Coulter). it can.

As a procedure for measuring the median diameter (D ₅₀ ) on a volume basis, 0.02 g of solid particles and 20 ml of a surfactant solution (for the purpose of dispersing solid particles, for example, neutral detergent containing a surfactant component with pure water). (10-fold diluted surfactant solution), followed by ultrasonic dispersion for 1 minute to produce a solid particle dispersion. This solid particle dispersion is poured into a beaker containing ISOTON II (manufactured by Coulter) in a sample stand with a pipette until a measurement concentration of 5 to 10% is reached, and the measurement is performed with a measuring machine count of 30000. To do. The aperture size of the multisizer 3 is 100 μm.

<Conductive agent>
Examples of the conductive agent include an electronic conductive agent and an ionic conductive agent. The resistance value can be adjusted by the kind of the conductive agent and the blending amount thereof.

(Electronic conductive agent)
Examples of the electronic conductive agent include various conductive metals or alloys such as carbon black, graphite, aluminum, copper, tin, and stainless steel, tin oxide, zinc oxide, indium oxide, titanium oxide, tin oxide antimony monoxide solid solution, tin oxide Various conductive metal oxides such as indium oxide solid solution, and fine powders such as insulating substances coated with these conductive materials can be used. Among these, carbon black is preferably used because it can be obtained relatively easily and good chargeability can be obtained.

  The type of carbon black is not particularly limited, and various conventionally known carbon blacks such as ketjen black, channel black, and furnace black can be used. The blending amount of carbon black is not particularly limited because it varies depending on the type of carbon black to be used. Usually, it is preferably 5 to 40 parts by mass, more preferably 10 to 30 parts by mass with respect to 100 parts by mass of the resin component. Part range.

(Ionic conductive agent)
As the ionic conductive agent, conventionally known inorganic ionic salts and organic ionic salts can be appropriately selected and used. Specifically, alkali metal halides such as Li, LiCl, NaI, NaBr, and KI, perchlorates such as LiClO ₄ , KClO ₄ , and CuC ₁₂ Mg (ClO ₄ ) ₂ , and thiocyanic acids such as LiSCN, NaSCN, and CsSCN Inorganic ion salts such as salts, aliphatic sulfonates, higher alcohol sulfates, higher alcohol phosphates, higher alcohol ethylene oxide addition sulfates, higher alcohol ethylene oxide addition phosphates, quaternary ammonium Examples thereof include organic ion salts such as salts and betaines. Among these, quaternary ammonium salts such as trimethyloctadecyl ammonium perchlorate, tetramethylammonium chloride, and benzyltrimethylammonium chloride are particularly preferable. These ionic conductive agents may be used alone or in combination of two or more.

  The blending amount of the ionic conductive agent is not particularly limited and is appropriately selected according to various situations, but is preferably 0.001 to 5 parts by mass with respect to 100 parts by mass of the binder resin component forming the coating layer. -2 mass parts is more preferable.

<< Filtration of coating liquid >>
The coating solution is filtered using a vibrating filter according to the flow shown in FIG. 2 and used for coating the substrate. Specifically, it is filtered by a filter that vibrates in a specific direction with a specific vibration frequency and a specific vibration amplitude.

<Formation of coating layer>
The filtered coating solution is applied to the outer periphery of the substrate to form a coating layer.

The substrate is preferably made of a conductive metal (for example, 1 × 10 ⁻³ Ω · cm or less) because it also serves as a member that leaks charges accumulated on the surface of the developing roller. Typical examples include conductive metals such as stainless steel (for example, SUS303) having a diameter of 5 to 30 mm, iron, aluminum, nickel, an aluminum alloy, and a nickel alloy, and may be made of a conductive resin.

  The method of applying the coating solution to the outer periphery of the substrate is not particularly limited as long as it can be applied using a circulating and filtered coating solution, and includes a method of applying using the above-described coating apparatus.

  The coating layer formed by applying the coating solution to the outer periphery of the substrate is dried by a known method, and heat-treated as necessary to produce a developing roller.

  The layer structure of the coating layer is not particularly limited and may be a single layer structure or a two-layer structure of a lower layer and an upper layer, but has a two-layer structure suitable for preventing the occurrence of filming because of good adhesion to the substrate. Is preferred.

  The two-layer developing roller is formed by applying a coating solution containing at least a binder resin, solid particles, and a conductive agent to the outer periphery of the substrate to produce a lower layer, and containing at least the binder resin and the conductive agent on the lower layer. It is possible to obtain an upper layer by applying a coating liquid.

  FIG. 3 is a schematic sectional view showing an example of the developing roller.

  In FIG. 3, 32 is a developing roller, 1 is a substrate, 20 is a coating layer, 21 is an upper layer, 22 is a lower layer, 23 is a solid particle, and 24 is a conductive agent.

  FIG. 3A is a schematic view of a developing roller in which a coating layer 20 is formed on the outer periphery of the substrate 1. As shown in FIG. 3 (b), the coating layer has a single-layer coating layer 20 having solid particles 23 and a conductive agent 24 on the outer periphery of the substrate 1, and the substrate as shown in FIG. 3 (c). The upper layer 20 composed of the lower layer 22 having the solid particles 23 and the conductive agent 24 and the coating layer 21 having the conductive agent 24 may be provided on the outer periphery of 1.

  The film thickness of the coating layer of the developing roller is preferably 5 to 30 μm in which the leakage start DC voltage can be easily controlled. In the case of a two-layer structure, the film thickness of the lower layer is preferably 5 to 20 μm, and the film thickness of the coating layer is preferably 2 to 10 μm.

  The film thickness of the coating layer means an average value obtained by measuring 20 film thicknesses of the portion having no solid particles in FIG. In addition, although it measured with the eddy-current type film thickness meter "fischerscope" (made by Fischer) as a film thickness measuring device, if it is a film thickness measuring device which has the same measurement precision, a measuring device will not ask | require.

<< Development roller manufacturing flow chart >>
Next, although the manufacturing flowchart of a developing roller is shown, this invention is not limited to this.

  FIG. 4 is a schematic diagram showing an example of a manufacturing flow of a developing roller for applying the coating liquid filtered by the vibrating filter to the outer periphery of the substrate.

  In FIG. 4, A is a binder resin, B is solid particles, C is an additive, D is a solvent, 21 is a dissolution mixer, 22 is a disperser, 1 is a coating solution storage tank, 2 is a feed pump, 3 is Filtration device, 4 is a filter, 5 is a vibration generating device, 6 is a filter disk, 7 is a coating device, 8 is a substrate, 9 is a liquid feeding tube, 10 is a return liquid tube, 11 is a coating solution, and 23 is a drying device. .

  The manufacturing flow of FIG. 4 will be described. The materials of the coating liquid (binder resin A, solid particles B, additive C and solvent D) are mixed in the dissolution mixer 21 and dissolved and mixed. In the solution thus mixed, solid particles are dispersed by the disperser 22 to prepare the dispersion 11. This dispersion is stored in the coating liquid storage tank 1.

  The dispersion liquid stored in the coating liquid storage tank 1 is sent to the filtration device 3 by the liquid feed pump 2 and filtered, and foreign matters in the dispersion liquid are removed. A filter 4 that vibrates is attached to the filtering device 3. The filtered coating solution is sent to the coating device 7, and the coating solution is applied to the outer periphery of the substrate 8. The coated substrate 8 is dried by the drying device 23 to form a coating layer.

  The overflowing coating liquid is returned to the coating liquid storage tank 1 through the return liquid pipe 10 and reused.

<Image forming apparatus>
Next, an image forming apparatus for evaluating the performance of the developing roller produced by the method for producing an electrophotographic member of the present invention will be described.

  The developing roller according to the present invention visualizes the latent image using a developing device that holds and conveys a non-magnetic one-component developer on the surface thereof and attaches the developer to the latent image on the surface of the latent image carrier. Used in an image forming method.

  FIG. 5 is a schematic cross-sectional view showing an example of a developing device to which the developing roller according to the present invention is attached.

  In FIG. 5, reference numeral 10 denotes a latent image holding member (photosensitive drum), and latent image formation is performed by electrophotographic process means or electrostatic recording means (not shown). A developing roller 32 is provided with a coating layer on a base made of aluminum or stainless steel.

  The toner T is stored in the hopper 6 and is supplied onto the developing roller by the supply roll 4. The supply roll is made of a foam material such as polyurethane foam, and rotates at a relative speed in the forward or reverse direction with respect to the developing roller 32. The toner is supplied and the developed toner (undeveloped toner) on the developing roller is supplied. We are also stripping off. A uniform toner thin layer is formed on the toner supplied onto the developing roller 32 by a toner regulating blade 5 which is a kind of member that performs toner thinning and charging.

  The contact pressure between the toner regulating blade and the developing roller is 3 to 250 N / m, preferably 10 to 30 N / m, as the linear pressure in the developing roller bus direction. When the contact pressure is within the above range, if it is less than 3 N / m, it is difficult to form a uniform toner thin layer, and the toner charge amount distribution becomes broad, which may cause fogging or scattering. On the other hand, if the contact pressure exceeds 250 N / m, a large pressure is applied to the toner and the toner deteriorates, which is not preferable because toner aggregation occurs. Further, it is not preferable because a large torque is required to drive the developing roller. That is, by adjusting the contact pressure to 3 to 250 N / m, the toner charge amount can be instantaneously increased.

  Examples of the toner regulating blade 5 for forming and charging a uniform thin layer of toner include an elastic blade and an elastic roller, and are formed of a material capable of charging the toner to a desired polarity by frictional charging.

  In the case of non-magnetic one-component toner in which the toner is thinly coated on the developing roller by the toner regulating blade, the thickness of the toner layer on the developing roller is set to the developing roller and the photosensitive drum in order to obtain a sufficient image density. It is preferable to use a so-called non-contact development method and apply an alternating electric field to this gap. A gap of 50 to 500 μm, more preferably 100 to 300 μm, is provided between the photoreceptor surface and the developing roller surface. On the other hand, the toner layer provided on the developing roller overlaps with about 1 to 3 toner particles. A toner layer of ˜30 μm is preferable. Note that the film thickness of the toner layer on the developing roller can be obtained by microscopic observation.

  Next, a full color image forming apparatus using a developing device loaded with the developing roller according to the present invention will be described.

  FIG. 6 is a schematic cross-sectional view showing an example of a full-color image forming apparatus.

  In the full-color image forming apparatus shown in FIG. 6, a charging unit 111 for uniformly charging the surface of the photosensitive drum 10 to a predetermined potential around the photosensitive drum 10 that is driven to rotate, A cleaner 112 for scraping off the remaining toner is provided.

  Also provided is a laser scanning optical system 20 that scans and exposes the photosensitive drum 10 charged by the charging means 111 with a laser beam. The laser scanning optical system 20 includes a laser diode, a polygon mirror, and an fθ optical element. The print data for each of yellow, magenta, cyan, and black is transferred from the host computer to the control unit. The laser scanning optical system 20 sequentially outputs the laser beam as a laser beam based on the print data for each color, scans and exposes the photosensitive drum 10, and thereby the static image for each color is formed on the photosensitive drum 10. Electro latent images are sequentially formed.

  In addition, the full-color developing device 30 that supplies full-color development to the photosensitive drum 10 on which the electrostatic latent image is formed in this manner, performs yellow, magenta, cyan, and black around the support shaft 33. Four color-developing units 31Y, 31M, 31C, and 31Bk each containing non-magnetic one-component toner are provided. The developing units 31Y, 31M, 31C, and 31Bk rotate around the support shaft 33, and It is guided to a position facing the photosensitive drum 10.

  Further, in each of the developing devices 31Y, 31M, 31C, and 31Bk in the full-color developing device 30, as shown in FIG. 6, the toner is formed on the outer peripheral surface of the developer carrying member (developing roller) 32 that rotates and conveys the toner. A regulating member is in pressure contact, and the toner regulating member regulates the amount of toner conveyed by the developing roller 32 and charges the conveyed toner. In this full-color developing device 30, two toner regulating members may be provided in order to properly regulate and charge the toner conveyed by the developing roller 32.

  Then, whenever the electrostatic latent image of each color is formed on the photosensitive drum 10 by the laser scanning optical system 20 as described above, the full-color developing device 30 is rotated around the support shaft 33 as described above. Then, the developing devices 31Y, 31M, 31C, and 31Bk containing toner of the corresponding colors are sequentially guided to positions facing the photosensitive drum 10, and the developing rollers 32 in the developing devices 31Y, 31M, 31C, and 31Bk are moved. Development is performed by sequentially supplying charged toner of each color onto the photosensitive drum 10 in which the electrostatic latent images of the respective colors are sequentially formed as described above without contact with the photosensitive drum 10. It has become.

  Further, an endless intermediate transfer belt 40 that is rotationally driven is provided as an intermediate transfer body at a position downstream of the full-color developing device 30 in the rotation direction of the photosensitive drum 10. The photosensitive drum 10 is rotated in synchronization with the photosensitive drum 10. The intermediate transfer belt 40 is pressed by a rotatable primary transfer roller 41 so as to come into contact with the photosensitive drum 10, and a portion of a support roller 42 that supports the intermediate transfer belt 40 includes: A secondary transfer roller 43 is rotatably provided, and the recording material S such as recording paper is pressed against the intermediate transfer belt 40 by the secondary transfer roller 43.

  Further, a cleaner 50 that scrapes off the toner remaining on the intermediate transfer belt 40 is provided in a space between the full-color developing device 30 and the intermediate transfer belt 40 so as to be able to contact with and separate from the intermediate transfer belt 40. ing.

  Further, the paper feeding means 60 that guides the recording material S such as plain paper to the intermediate transfer belt 40 includes a paper feeding tray 61 that accommodates the recording material S and the recording material S that is accommodated in the paper feeding tray 61 one by one. The recording material S fed in synchronization with the paper feed roller 62 for feeding paper and the image formed on the intermediate transfer belt 40 is sent between the intermediate transfer belt 40 and the secondary transfer roller 43. The recording material S sent between the intermediate transfer belt 40 and the secondary transfer roller 43 in this way is pressed against the intermediate transfer belt 40 by the secondary transfer roller 43. The toner image is pressed and transferred from the intermediate transfer belt 40 to the recording material S.

  On the other hand, the recording material S on which the toner image is pressed and transferred as described above is guided to the fixing device 70 by the conveying means 66 constituted by an air suction belt or the like, and is transferred by the fixing device 70. The toner image is fixed on the recording material S, and then the recording material S is discharged onto the upper surface of the apparatus main body 100 through the vertical conveyance path 80.

  Next, the operation of forming a full color image using this full color image forming apparatus will be specifically described.

  First, the photosensitive drum 10 and the intermediate transfer belt 40 are rotationally driven in the respective directions at the same peripheral speed, and the photosensitive drum 10 is charged to a predetermined potential by the charging unit 111.

  The photosensitive drum 10 thus charged is exposed to a yellow image by the laser scanning optical system 20 to form an electrostatic latent image of the yellow image on the photosensitive drum 10. The yellow image is developed by supplying the yellow toner charged by the toner regulating member as described above from the developing device 31Y in which the yellow toner is accommodated in the photosensitive drum 10, and the yellow toner image is thus formed. The intermediate transfer belt 40 is pressed against the body drum 10 by the primary transfer roller 41, and the yellow toner image formed on the photosensitive drum 10 is primarily transferred to the intermediate transfer belt 40.

  After the yellow toner image is transferred to the intermediate transfer belt 40 in this way, the full-color developing device 30 is rotated around the support shaft 33 as described above, and the developing device 31M containing magenta toner is exposed to light. As in the case of the yellow image described above, the magenta image is exposed to the photosensitive drum 10 charged by the laser scanning optical system 20 to form an electrostatic latent image. The electrostatic latent image is developed by a developing device 31M containing magenta toner, and the developed magenta toner image is primarily transferred from the photosensitive drum 10 to the intermediate transfer belt 40. Black image exposure, development and primary transfer are sequentially performed, and yellow, magenta, cyan, and black toner images are sequentially superimposed on the intermediate transfer belt 40. To form a toner image of Rukara.

  When the final black toner image is primarily transferred onto the intermediate transfer belt 40, the recording material S is fed between the secondary transfer roller 43 and the intermediate transfer belt 40 by the timing roller 63, and the secondary transfer roller. The recording material S is pressed against the intermediate transfer belt 40 by 43, and the full color toner image formed on the intermediate transfer belt 40 is secondarily transferred onto the recording material S.

  When the full-color toner image is secondarily transferred onto the recording material S in this way, the recording material S is guided to the fixing device 70 by the conveying means 66, and the full-color toner transferred by the fixing device 70 is transferred. The image is fixed on the recording material S, and then the recording material S is discharged onto the upper surface of the apparatus main body 1 through the vertical conveyance path 80.

  In the following, a developing roller is given as an example of the electrophotographic member of the present invention, and the production method thereof will be specifically described. However, embodiments of the present invention are not limited to these.

<Production of developing roller>
A developing roller was prepared according to the following procedure.

<Preparation of substrate>
A cylindrical substrate made of SUS303 was prepared as a substrate for the developing roller. This is referred to as “base 1”.

<Preparation of solid particles>
Cross-linked acrylic resin particles having a median diameter (D ₅₀ ) of 20.0 μm on a volume basis were prepared. This is designated as “solid particles 1”.

<Preparation of developing roller 1>
(Formation of coating layer)
Carbon black “Ketjen Black EC300J” (manufactured by Lion) 15 mass as a conductive agent in a solution obtained by dissolving 100 parts by mass of urethane resin “Nipporan 5199” (manufactured by Nippon Polyurethane), which is a thermoplastic elastomer, in 500 parts by mass of methyl ethyl ketone Part and 20 parts by mass of “solid particles 1” were dispersed using a sand mill for 2 hours to prepare a coating solution. This is designated as “Coating liquid 1”.

  The developing roller 1 was manufactured according to the manufacturing flow shown in FIG.

  “Coating liquid 1” filtered under the following filtration conditions is applied to the surface of “shaft body 1” by overflow dip coating, and then dried at 120 ° C. for 1 hour to form a coating layer having a thickness of 10 μm. Developing roller 1 "was produced.

Manufacturing conditions Filtration device: Type that filters application liquid with vibrating filter Filter: Mesh type Opening of filter: 40μm
Vibration generator: Piston type vibration generator using air
Vibration frequency 1Hz
Vibration amplitude 0.1mm
Vibration direction Perpendicular to the filter Coating device: Overflow dip coating device Manufacturing flow: Flow shown in Fig. 4 When the developing roller was produced under the above filtration conditions, clogging of the filter was not observed and the 500th product was produced. Could be done.

<Preparation of developing rollers 2 to 15>
“Developing rollers 2 to 15” were prepared in the same manner except that the filtration conditions of “application liquid 1” were changed as shown in Table 1 in the production of developing roller 1.

  The developing roller was produced under the above manufacturing conditions. When clogging occurred, application was stopped at that stage.

<Preparation of developing roller 16>
“Developing roller 16” was prepared in the same manner except that the vibration of the filtration device was stopped in the production of developing roller 1.

  Note that, under the manufacturing conditions in which the vibration of the filtration device was stopped, the filter was clogged, and the developing roller could not be produced.

<Preparation of developing roller 17>
In the production of the developing roller 1, the “developing roller 17” is similarly installed except that an ultrasonic oscillation device is attached outside the filtering device instead of the vibration generating device of the filtering device, and filtration is performed while irradiating ultrasonic waves. Produced.

  Under the manufacturing conditions of the ultrasonic oscillator, the filter was not clogged up to the 1000th, but there were many coating defects due to bubbles.

  Table 1 shows the particle size of the solid particles used in the preparation of the coating liquid, the filtration conditions, and the number of the particles until clogging.

<Evaluation>
<Uniformity of electrical resistance value = initial image defect>
Evaluation of the uniformity of the electrical resistance value is caused by defects in the developing roller in the halftone image obtained by printing 10 halftone cyan images with an image density of 0.3 on A4 size transfer paper. The degree of occurrence of black spots and white spots was visually observed and evaluated.

  For the formation of a print image, a color laser printer “Magicor 2430DL (manufactured by Konica Minolta Business Technologies)” is prepared as an image forming apparatus, and the developing roller produced as described above is sequentially mounted on the developing device of the image forming apparatus. I went there.

Evaluation criteria A: Uniform image with no black or white spots in the halftone image ○: There are black spots or white spots in the halftone image, but there is no practical problem ×: Black spots or white spots in the halftone image There are many problems in practical use.

<Durability = Image defects after durability>
The durability of the developing roller is evaluated by preparing a color laser printer “Magicor 2430DL (manufactured by Konica Minolta Business Technologies)” as an image forming apparatus, and sequentially mounting the developing rollers prepared above on the developing apparatus of the image forming apparatus, Print out 5,000 halftone cyan images with an image density of 0.3 on A4 size transfer paper, and print out halftone images with black spots and white spots caused by developing roller defects. Was visually evaluated.

Evaluation criteria A: Uniform image with no black or white spots in the halftone image ○: There are black spots or white spots in the halftone image, but there is no practical problem ×: Black spots or white spots in the halftone image There are many problems in practical use.

  Table 2 shows the evaluation results of the uniformity and durability of the electrical resistance value.

  As shown in Table 2, the “developing rollers 1 to 15” of Examples 1 to 15 corresponding to the present invention can be produced up to the 500th without clogging of the filter, and the evaluation results of uniformity of electric resistance and durability Was also good.

  Incidentally, the “developing roller 16” of Comparative Example 1 outside the present invention was not able to produce a sample due to the clogging of the filter as shown in Table 1. Further, it was confirmed that the “developing roller 16” of Comparative Example 2 has a problem in any of the evaluation items and does not manifest the present invention.

It is a schematic diagram which shows the state which is filtering the coating liquid which has a solid particle using a filter. It is a schematic diagram which shows an example of the manufacture flow which apply | coats the coating liquid currently filtered by the filter which vibrates to the outer periphery of a base | substrate. It is a cross-sectional schematic diagram which shows an example of a developing roller. It is a schematic diagram showing an example of a manufacturing flow of a developing roller that applies a coating liquid that is circulated and filtered by a vibrating filter to the outer periphery of a substrate. FIG. 2 is a schematic cross-sectional view showing an example of a developing device to which the developing roller according to the present invention is attached. It is a schematic sectional drawing which shows an example of a full-color image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coating liquid storage tank 2 Liquid feeding pump 3 Filtration apparatus 4 Filter 5 Vibration generator 6 Filter disk 7 Coating apparatus 8 Base body 9 Liquid feeding pipe 10 Return liquid pipe 11 Coating liquid

Claims (4)

An electrophotographic member manufacturing method comprising a step of forming a coating layer by applying a coating solution to at least the outer periphery of a substrate,
A method for producing an electrophotographic member, wherein the coating liquid that has passed through a vibrating filter is applied to the outer periphery of a substrate. In the circulation path that passes the coating liquid through the coating operation unit,
The method for producing an electrophotographic member according to claim 1, wherein the electrophotographic member is passed through a vibrating filter. The vibration frequency of a vibration source that vibrates the filter is 10 to 5000 Hz, the vibration amplitude is 0.1 to 5 mm, and the vibration direction is a direction perpendicular to the filter surface. A method for producing an electrophotographic member. An electrophotographic member produced by the method for producing an electrophotographic member according to claim 1.

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