JP5301754B2 - Developer carrier and developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developer carrying member which makes it possible to obtain good images regardless of decreasingly lower hardness of members by accompanying a trend toward higher quality of the images and coloring with an image forming device of an electrophotographic system and electrostatic recording. SOLUTION: This developer carrying member is a developer carrying member having a role of developing the latent images and is molded with an elastic body layer consisting of silicone rubber as a main raw material by injecting or casting on the outer periphery of a core body, is formed with at least one elastic coating layers on the outer periphery of the outer peripheral surface of the elastic body layer without performing shaping by grinding or machining, is provided with a barrier layer designed to prevent the migration of low- molecular weight contaminants which are the materials bled from the silicone rubber on at least one layer among the elastic coating layers and is provided with a firm sticking preventive layer containing an organic fluorine compound and/or silicone compound to as a portion or the whole resin components on at least the outermost layer of the elastic coating layers.

Description

  The present invention relates to a developer carrier used in a developing device of an electrophotographic or electrostatic image forming apparatus such as a copying machine, a facsimile machine, and a printer, and a developing device equipped with the developer carrier.

  In recent years, with respect to developer carriers used in electrophotographic or electrostatic recording type image forming apparatuses such as copying machines, facsimiles, printers, etc., the developer carrier used for colorizing images and improving image quality is used. The problem of serious damage to the developer on the contact surface with the developer amount regulating blade, developer supply body, etc. due to the finer particle size or the low softening point of the developer performed for power saving. It has become. Therefore, for the purpose of reducing such developer damage, it is required to reduce the hardness of the material forming the developer carrier.

2. Description of the Related Art Conventionally, in a developing device of an image forming apparatus such as a copying machine, a facsimile, or a printer, as shown in FIG. 1, for example, a developer is first applied to a developer carrier 2 from a blade or roll-shaped developer supply body 1. 3 is supplied, and then the developer 3 conveyed in the direction of the arrow by the rotation of the developer carrier 2 is arranged so that the developer carrier 2 and the developer carrier 2 are in pressure contact with each other. By passing between the amount regulating blade 4, the developer 3 on the developer carrier 2 is regulated to an appropriate thickness, and at the same time, the developer is caused by frictional charging between the developer amount regulating blade 4 and the developer 3. 3 is charged with an appropriate charge, and the developer 3 is applied to the electrostatic latent image formed in advance on the latent image carrier 5 which is in contact with the developer carrier 2 or arranged at a certain distance. Development is performed by adhering. Here, at the end of the developer carrier 2, a developer sealing member 18 is disposed in pressure contact with the developer carrier 2 for the purpose of preventing leakage of the developer 3.
In general, the developer carrier 2 has a configuration in which at least one elastic layer made of resin, rubber, elastomer, or the like is formed on the outer periphery of a core made of metal such as phosphor bronze, stainless steel, aluminum, or iron. ing. Specifically, as the main material of the elastic body forming the elastic layer, rubber materials such as diene rubber, urethane rubber, EPDM (ethylene propylene diene rubber), silicone rubber, polyol compounds, etc. are cured with a polyisocyanate compound. The urethane elastomer etc. which become. Among these, the use of silicone rubber is preferable in consideration of the necessity of reducing the compression set in order to suppress shape deformation due to pressure contact and the reduction in hardness for reducing developer damage.
In general, the outer peripheral surface of the elastic layer is processed by polishing, cutting, or the like in order to ensure dimensional accuracy after being molded. In order to omit the shape processing, there is a method of obtaining a molded body having an elastic body layer having a target outer diameter by using a mold with a split surface, but in this case, molding is caused by the flow of rubber at the split surface portion. Variations in electrical resistance in the body occur, resulting in image defects, making it difficult to design a mold.

Problems to be solved by the invention

However, for the reasons described above, when a low hardness silicone rubber is used to form the developer bearing member, there has been a problem that processing such as polishing and cutting becomes difficult. This is due to rubber escape and chatter on the machined surface due to low hardness. As countermeasures against this, methods such as wet polishing and precision polishing with cloth, paper, etc. are generally employed. However, any method has a problem that the tact time becomes long and productivity is lowered.
Further, when a low hardness silicone rubber was used, an image defect due to contamination of the latent image carrier in contact with the developer carrier occurred. That is, the low hardness of the silicone rubber increases the amount of low molecular weight contaminants contained in the silicone rubber, and the low molecular weight contaminants bleed out and adhere to the contact surface of the latent image carrier and cause image defects. It is. This is conspicuous in the millable type silicone, and is relatively light in the cured product of the addition reaction type liquid silicone rubber material. As a countermeasure, it is common to provide a barrier layer on the elastic layer. Specifically, the barrier layer is formed of a polar resin, and the migration of low molecular weight contaminants due to the difference in solubility is prevented. There is a method in which a protective layer having a sufficient thickness is provided to physically prevent migration of low molecular weight contaminants.
However, in the former case, as a characteristic of the polar resin, there is a problem of adhesion with other members in contact with the developer carrier, and even in the latter case, a sufficiently thick film is formed and the hardness of the developer carrier is In order not to increase the thickness, it is necessary to use a low-hardness coating material, and similarly, the problem of adhesion cannot be avoided.
The present invention has been made in view of the above circumstances. In an electrophotographic or electrostatic recording image forming apparatus, the present invention relates to a reduction in the hardness of a member that is required as a result of higher image quality and colorization. A developer carrying member capable of obtaining a good image without contaminating other members or being in close contact with the other members and having high electrical resistance and dimensional stability, and a developing device equipped with the developer carrying member. The purpose is to provide.

Means for solving the problem

As a result of intensive studies to achieve the above object, the inventors of the present invention have found that, in the developer carrier, the elastic body layer is formed of an elastic body mainly composed of silicone rubber, thereby achieving low hardness and low Compressive strain is achieved, a nip width necessary for high-quality images can be secured, and at least one elastic coating layer is provided on the outer periphery, and at least one of the elastic coating layers is a bleed from silicone rubber. By providing a barrier layer for the purpose of preventing the migration of low molecular weight contaminants, it is possible to prevent contamination of the latent image carrier, and further, at least the outermost layer of the elastic coating layer has a part or all of the resin component. As described above, by providing an adhesion preventing layer containing an organic fluorine compound and / or a silicone compound, the barrier layer having adhesion can adhere to another member that is in pressure contact. Found that capable of preventing. Here, only one layer of an elastic coating layer containing an organic fluorine compound and / or a silicone compound as a part or all of the resin component and capable of preventing migration of low molecular weight contaminants which are bleeds of bleed from silicone rubber. It was also found that the purpose can be achieved by providing.
In addition, in the developer carrier, the elastic layer mainly composed of silicone rubber is formed by heating and curing an addition reaction type liquid silicone rubber material. In addition, the present inventors have found that an elastic body layer having a low compression set and a low hardness can be realized, and a developer carrier satisfying higher image quality requirements can be obtained. The problem in handling low-hardness solid raw materials here is that it is difficult to store uncured raw materials due to the high cold flow properties of the raw materials, and the green strength of the raw materials is low. It is difficult to continue to input.
Furthermore, when the elastic layer is formed on the developer carrier, the shake of the molded body (elastic body layer) can be suppressed by accurately fixing the core, and by using a nested or cylindrical mold There is no variation in electrical resistance due to the fluidity of rubber, a molded body having the desired outer diameter of the elastic layer can be obtained, and the work grinding process of the outer peripheral surface by polishing, cutting, etc. can be omitted. I found it.
Furthermore, in the developing device, the use of the developer carrying member may cause contamination of other members or adhesion to other members regardless of the decrease in hardness of the press contact portion for the purpose of improving image quality. It has been found that the developing device can stably obtain a good image quality.
The present invention has been completed based on such findings.

  That is, according to the present invention, (1) the developer supplied from the developer supply member is carried on the surface, and the latent image is developed by supplying the developer to the latent image formed on the latent image carrier. In the developer carrying member having the role of forming an elastic body layer made of silicone rubber as a main raw material on the outer periphery of the core body by injection or casting, the outer peripheral surface of the elastic body layer is shaped by grinding or cutting A barrier layer for the purpose of preventing migration of low molecular weight contaminants, which are bleeds from silicone rubber, on at least one of the elastic coating layers without forming And an adhesion-preventing layer containing an organic fluorine compound and / or a silicone compound as a part or all of the resin component is provided on at least the outermost layer of the elastic coating layer. (2) The developer carrier according to (1) above, wherein the elastic body layer mainly composed of silicone rubber is a molded body obtained by heating and curing an addition reaction type liquid silicone rubber material, ) A mold having a recess for fixing a cylindrical insert for forming an outer peripheral surface of the core body and the outer diameter of the elastic body layer, or an end cap for fixing the core body And the developer carrying member according to (1) or (2), wherein the developer carrying member is formed by a cylindrical mold for forming an outer peripheral surface having a target outer diameter of the elastic layer, and (4) A developing device provided with the developer carrying member according to any one of (1) to (3) is provided.

As the developer carrier of the present invention, for example, as shown in FIG. 2A, an elastic body layer 6 is formed on the outer peripheral surface of the core body 15, and at least one elastic coating layer is formed on the outer peripheral surface of the elastic body layer 6. 7 (barrier layer) and an elastic coating layer 16 (adhesion prevention layer) formed on the outer peripheral surface of the elastic coating layer 7 (barrier layer), and as shown in FIG. In which at least one elastic coating layer 17 (barrier layer + adhesion prevention layer) is formed on the outer peripheral surface of the substrate.
Examples of the metal forming the core 15 include iron, copper, white, stainless, phosphor bronze, and the resin includes polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyurethane, polyamide, polyacetal, Examples thereof include synthetic resins such as polycarbonate, polyethylene terephthalate, polyimide, polyamideimide, polyester, phenol resin, melamine resin, silicone resin, epoxy resin, acrylic resin, methacrylic resin, and urea resin.

  The elastic body layer 6 is formed of a raw material mainly composed of silicone rubber, but as an elastic body other than silicone rubber, natural rubber, isoprene rubber, butadiene rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, chloroprene rubber, Rubber materials such as ethylene / propylene rubber, ethylene / propylene terpolymer (EPDM), butyl rubber, acrylic rubber, chlorosulfonated polyethylene, fluorine rubber, polyether rubber, epichlorohydrin rubber, urethane rubber, polyurethane, silicone, polystyrene / polybutadiene block Examples thereof include elastomers such as polymers, polyolefins, polyethylene, chlorinated polyethylene, and ethylene / vinyl acetate copolymers. The amount of the silicone rubber and the elastic body other than the silicone rubber is preferably 70% by mass or more of the silicone rubber in the elastic body, and considering the low hardness and low compression set, the silicone rubber is 100% by mass. It is preferable. As the silicone rubber, a silicone rubber obtained by heating and curing an addition reaction type liquid silicone rubber material is more preferable. Since the liquid silicone rubber has fewer low molecular weight components than the millable type silicone, the film thickness of the barrier layer can be suppressed. Therefore, when this is used, an intermediate transfer member having a lower hardness can be obtained. . The thickness of the elastic layer can be 0.5 to 10 mm, and preferably 1 to 5 mm.

As a means for forming the elastic body layer 6 on the outer peripheral surface of the core body 15, in general, it is integrally formed with the core body by coating, injection, casting, extrusion molding, or previously formed into a cylindrical shape and formed into an appropriate shape. The core body 15 can be inserted into the cut elastic body and bonded. Among these, the method using the split mold shown in FIGS. 3 and 4 and the method using the cylindrical mold shown in FIG. 5 are preferable. FIG. 3 shows an outline of the split mold as viewed from above, and FIG. 4 shows an outline of the split mold as viewed from the side. FIG. 5 shows a schematic cross section of a cylindrical mold.
The method using the split surface mold shown in FIG. 3 and FIG. 4 has a cavity for immobilizing the drum-shaped core body 15 and the insert 8 for forming the outer peripheral surface serving as the target outer diameter of the elastic layer. In this method, the core 15 and the insert 8 are arranged on the split surface 11 of the mold and the molds are overlapped with each other at an appropriate pressure, and then a silicone rubber material is injected from the injection machine and cured by heating. In FIG.3 and FIG.4, 9 is a runner part and 10 is a tab.
The method using the cylindrical mold shown in FIG. 5 has the end cap 13 having a mechanism for fixing the core body 15 and being fixed at a predetermined position relative to the cylindrical mold 12, and the desired outer diameter of the elastic layer. In this method, the core body 15 is fixed to the cylindrical mold 12 for forming the outer peripheral surface, and liquid silicone is cast from the casting hole 14 using a pump, and then is cured by heating and molding.

An adhesive layer may be provided between the core body 15 and the elastic body layer 6 as necessary. As the adhesive, various silicone primers, coupling agents such as silane and titanium, hot melt agents such as polypropylene, polyethylene, EVA (ethylene-vinyl acetate copolymer), and acrylic resin can be used.
Examples of the elastic body forming the elastic coating layer 7 include polyester resin, polyether resin, fluorine resin, epoxy resin, amino resin, polyamide resin, acrylic resin, acrylic urethane resin, urethane resin, alkyd resin, phenol resin, melamine resin, Examples include urea resins, silicone resins, and polyvinyl butyral resins. These can be used individually by 1 type or in mixture of 2 or more types. However, when the elastic coating layer 17 is formed as the outermost layer on the outer periphery of the elastic layer 6, the same resin component as that forming the elastic coating layer 7 can be used. Alternatively, it is necessary to replace the whole with an organic fluorine compound and / or a silicone compound. You may add additives, such as fillers, such as carbon, and a charge control agent, to the elastic coating layer 7 and the elastic coating layer 17, as needed. The thickness of the elastic coating layers 7 and 17 can be 0.5 to 300 μm, preferably 1 to 50 μm.
Examples of organic fluorine compounds include fluorine-containing polymer compounds such as polyvinylidene fluoride, Teflon, and perfluoro-grafted acrylic resins, and fluorine-containing compounds such as perfluoroalkyl compounds having functional groups at one end, both ends, or side chains. It is done. Examples of the silicone compound include silicone-containing polymer compounds such as silicone resins, silicone-modified acrylic resins, and silicone-modified urethane resins, and silicone-containing compounds such as modified silicone oils having functional groups at one end, both ends, or side chains. In the present invention, when used as the entire resin component, a fluorine-containing polymer compound mainly composed of polyvinylidene fluoride is preferable. When used as a part of the resin component, one end, both ends, or side chains are used. Preferred are fluorine-containing compounds and silicone-containing compounds having a functional group.
The content of the organic fluorine compound and / or the silicone compound is preferably 0.5% by mass or more, more preferably 1.0% by mass or more in the elastic coating layer.

As a means for forming the elastic coating layer 7 or 17 on the outer peripheral surface of the elastic body layer 6, generally, coating, in-mold coating, or coating by shrinking a shrink tube formed in a cylindrical shape in advance by heating, etc. The method is adopted. An adhesive layer may be provided between the elastic body layer 6 and the elastic coating layer 7 as necessary. As the adhesive, the same ones as described above can be used.
Examples of the elastic body used for the elastic coating layer 16 formed on the outer peripheral surface of the elastic coating layer 7 include polyester resin, polyether resin, fluorine resin, epoxy resin, amino resin, polyamide resin, acrylic resin, acrylic urethane resin, urethane resin, Examples thereof include alkyd resins, phenol resins, melamine resins, urea resins, silicone resins, and polyvinyl butyral resins. These can be used individually by 1 type or in mixture of 2 or more types. It is necessary to contain an organic fluorine compound and / or a silicone compound as part or all of the resin component, and the preferred content is the same as described above. The thickness of the elastic coating layer 16 can be 0.5 to 10 μm, and preferably 1 to 5 μm.
You may add additives, such as fillers, such as carbon, and a charge control agent, to the elastic coating layer 16 as needed. An adhesive layer may be provided between the elastic coating layer 7 and the elastic coating layer 16 as necessary. As the adhesive, the same ones as described above can be used.

EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these examples.
[Example 1]
The developer carrying member shown in FIG. 2A was produced as follows. The following semiconducting millable silicone rubber raw material of elastic body composition 1 is mixed, and this is injected into the split surface mold shown in FIGS. An elastic body layer is formed by heating and curing, demolded from the insert 8, and subjected to secondary vulcanization at 200 ° C. for 4 hours to obtain a roll-shaped formed body having an elastic body layer 6 having a thickness of 5 mm. It was. The elastic layer 6 had an Asker C hardness of 55 °. The Asker C hardness was measured according to JIS K6301.

(Elastic body blend 1)
SE4369U (Toray Dow Corning Silicone Co., Ltd .: Millable Silicone) 100.0 g
RC-4 50PDF (Toray Dow Corning Silicone Co., Ltd .: Crosslinker) 1.5g
On the outer peripheral surface of the elastic layer 7, primer No. 4 (manufactured by Shin-Etsu Chemical Co., Ltd .: adhesive) was applied by a dipping method and allowed to stand at room temperature for 30 minutes to form an adhesive layer. A coating material was prepared by mixing the following components of coating formulation 1, and applied to the outer peripheral surface of the adhesive layer by a dipping method, followed by heat curing at 110 ° C. for 1 hour to form an elastic coating layer 7. The film thickness of the elastic coating layer 7 was 15 μm.

(Coating composition 1)
EAU65B (Asia Kogyo Co., Ltd .: acrylic urethane paint) 100.0 g
MEK (manufactured by Kanto Chemical Co., Inc .: solvent, methyl ethyl ketone) 360.0 g
Carbon black # 2400B (Mitsubishi Chemical Corporation: carbon black) 20.0g
Nipseal SS-20 (Nippon Silica Kogyo Co., Ltd .: hydrophobic silica) 10.0 g
Excel Hardener HX (Asia Kogyo Co., Ltd .: Hardener) 11.0g
A coating composition is prepared by mixing the following components of coating composition 2, and applied to the outer peripheral surface of the elastic coating layer 7 by dipping, and cured by heating at 110 ° C. for 1 hour to form an elastic coating layer 16. A developer carrier shown in 2 (a) was produced. The film thickness of the elastic coating layer 16 was 2 μm.

(Coating composition 2)
Lumiflon LF200 (Asahi Glass Co., Ltd .: Fluororesin paint) 8.2g
MEK (manufactured by Kanto Chemical Co., Inc .: solvent, methyl ethyl ketone) 200.0 g
Excel Hardener HX (Asia Kogyo Co., Ltd .: Hardener) 1.4g
The resulting developer carrier was examined for variations in electrical resistance by the following method. That is, a flat metal electrode having a width of 1 cm is pressed against the roller surface with a pressure of 50 gf (about 0.5 N), and at a voltage of 100 V, the electrical resistance of the roller is 6 points in the longitudinal direction of the roller, and each of these 6 points is 4 in the circumferential direction of the roller. Measurement was performed for a total of 24 points, and the number of times the maximum value of electrical resistance was measured was calculated. In this developer carrying member, the maximum value of the measured electric resistance was 1.9 times the minimum value.
Next, the obtained developer carrying member is incorporated into the developing device shown in FIG. 1, and this developing device is attached to the image forming apparatus, and is subjected to high temperature and high humidity (temperature 50 ° C., humidity 90%, the same applies below). After standing for days, no contact or contamination was found at the contact part with other members. Further, no dimensional change of the developer carrying member was observed. When printing was performed using this image forming apparatus, no image defect occurred and a good image was obtained.

[Example 2]
The developer carrying member shown in FIG. 2A was produced as follows. In Example 1, the same procedure as in Example 1 was performed except that the elastic compound 1 was changed to the semiconductive addition reaction type liquid silicone of the elastic compound 2 below, and the heat curing conditions were changed to 130 ° C. for 1 minute. Thus, a roll-shaped molded body having an elastic layer 6 having a thickness of 5 mm was obtained. The elastic layer 6 had an Asker C hardness of 55 °.

(Elastic body blend 2)
DY35-4046-A (Toray Dow Corning Silicone Co., Ltd .: Liquid silicone) 50.0 g
DY35-4046-B (Toray Dow Corning Silicone Co., Ltd .: Liquid silicone) 50.0 g
On the outer peripheral surface of the elastic body layer 6, primer No. 4 (manufactured by Shin-Etsu Chemical Co., Ltd .: adhesive) was applied by a dipping method and allowed to stand at room temperature for 30 minutes to form an adhesive layer. A coating material was prepared by mixing the following ingredients of coating composition 3, and applied to the outer peripheral surface of the adhesive layer by dipping, and cured by heating at 110 ° C. for 1 hour to form elastic coating layer 7. The film thickness of the elastic coating layer 7 was 6 μm.

(Coating composition 3)
EAU65B (Asia Kogyo Co., Ltd .: acrylic urethane paint) 100.0 g
MEK (manufactured by Kanto Chemical Co., Inc .: solvent, methyl ethyl ketone) 500.0 g
Carbon black # 2400B (Mitsubishi Chemical Corporation: carbon black) 20.0 g Nipsil SS-20 (Nippon Silica Kogyo Co., Ltd .: hydrophobic silica) 10.0 g
Excel Hardener HX (Asia Kogyo Co., Ltd .: Hardener) 11.0g
In the same manner as in Example 1, the elastic coating layer 16 was formed on the outer peripheral surface of the elastic coating layer 7 to produce the developer carrying member shown in FIG.
The developer carrying member thus obtained was examined for variations in electrical resistance in the same manner as in Example 1. As a result, the maximum measured value of electrical resistance was 1.7 times the minimum value.
Next, the obtained developer carrying member is incorporated in the developing device shown in FIG. 1, and this developing device is mounted on the image forming apparatus and left for 14 days under high temperature and high humidity. There was no adhesion or contamination. Further, no dimensional change of the developer carrying member was observed. When printing was performed using this image forming apparatus, no image defect occurred and a good image was obtained.

[Example 3]
In Example 2, the mold used for heat-curing the elastic body layer 6 was changed to the cylindrical mold shown in FIG. 5, and the filling method of the material into the mold was changed to an injection method using a pump. In the same manner as in FIG. 2, a developer carrying member shown in FIG. The Asker C hardness of the elastic body layer 6 was 55 °.
The developer carrying member thus obtained was examined for variations in electric resistance in the same manner as in Example 1. As a result, the maximum value of the measured electric resistance was 1.8 times the minimum value.
Next, the obtained developer carrying member is incorporated in the developing device shown in FIG. 1, and this developing device is mounted on the image forming apparatus and left for 14 days under high temperature and high humidity. There was no adhesion or contamination. Further, no dimensional change of the developer carrying member was observed. When printing was performed using this image forming apparatus, no image defect occurred and a good image was obtained.

[Comparative Example 1]
In the split mold shown in FIG. 3 and FIG. 4, the material of the elastic body composition 1 is injected without using the insert 8, cured by heat, polished after secondary vulcanization, and molded into the desired shape. In the same manner as in Example 1, the developer carrying member shown in FIG. However, since a low-hardness elastic body was used, chattering occurred during polishing, resulting in an uneven developer carrier.
The developer carrying member thus obtained was examined for variations in electric resistance in the same manner as in Example 1. As a result, the maximum value of the measured electric resistance was 11.0 times the minimum value.
Next, the obtained developer carrying member is incorporated in the developing device shown in FIG. 1, and this developing device is mounted on the image forming apparatus and left for 14 days under high temperature and high humidity. There was no adhesion or contamination. When printing was performed using this image forming apparatus, image unevenness occurred and a good image could not be obtained.

[Comparative Example 2]
A developer carrying member shown in FIG. 2B was produced in the same manner as in Example 1 except that the elastic coating layer 16 was not formed.
The developer carrying member thus obtained was examined for variations in electrical resistance in the same manner as in Example 1. As a result, the maximum measured value of electrical resistance was 2.0 times the minimum value.
Next, the obtained developer carrying member is incorporated in the developing device shown in FIG. 1, and this developing device is mounted on the image forming apparatus and left at high temperature and high humidity for 14 days. I got stuck. When printing was performed using this image forming apparatus, the film was damaged during driving, and image defects occurred.

[Comparative Example 3]
A developer carrier shown in FIG. 2B was produced in the same manner as in Example 1 except that the elastic coating layer 7 was not formed.
The developer carrying member thus obtained was examined for variations in electrical resistance in the same manner as in Example 1. As a result, the maximum measured value of electrical resistance was 2.0 times the minimum value.
Next, the obtained developer carrying member is incorporated into the developing device shown in FIG. 1, and this developing device is attached to the image forming apparatus and left for 14 days under high temperature and high humidity. The photosensitive drum was contaminated at the part. Adhesion between the developer carrying member and the photosensitive drum was not recognized. When printing was performed using this image forming apparatus, an image defect estimated to be caused by contamination of the photosensitive drum occurred.

[Example 4]
In Example 1, the elastic coating layers 17 and 16 were not formed, and the elastic coating layer 17 was formed in the same manner as in Example 1 using the raw materials shown in the following film formulation 4 instead of the film formulation 1. A developer carrying member shown in (b) was produced.

(Coating composition 4)
EAU65B (Asia Kogyo Co., Ltd .: acrylic urethane paint) 100.0 g
MEK (manufactured by Kanto Chemical Co., Inc .: solvent, methyl ethyl ketone) 360.0 g
Carbon black # 2400B (Mitsubishi Chemical Corporation: carbon black) 20.0g
Nipseal SS-20 (Nippon Silica Kogyo Co., Ltd .: hydrophobic silica) 10.0 g
KF6003 (Shin-Etsu Chemical Co., Ltd .: terminal reactive silicone oil) 10.0 g
Excel Hardener HX (Asia Kogyo Co., Ltd .: Hardener) 13.4g
The obtained developer carrying member was examined for variations in electric resistance in the same manner as in Example 1. As a result, the maximum value of the measured electric resistance was 1.8 times the minimum value.
Next, the obtained developer carrying member is incorporated in the developing device shown in FIG. 1, and this developing device is mounted on the image forming apparatus and left for 14 days under high temperature and high humidity. There was no adhesion or contamination. Further, no dimensional change of the developer carrying member was observed. When printing was performed using this image forming apparatus, no image defect occurred and a good image was obtained.

[Example 5]
In Example 1, the elastic coating layers 7 and 16 were not formed, and the elastic coating layer 17 was formed in the same manner as in Example 1 using the raw materials shown in the following film formulation 5 instead of the film formulation 1. A developer carrying member shown in (b) was produced.

(Coating composition 5)
EAU65B (Asia Kogyo Co., Ltd .: acrylic urethane paint) 100.0 g
MEK (manufactured by Kanto Chemical Co., Inc .: solvent, methyl ethyl ketone) 360.0 g
Carbon black # 2400B (Mitsubishi Chemical Corporation: carbon black) 20.0g
Nipseal SS-20 (Nippon Silica Kogyo Co., Ltd .: hydrophobic silica) 10.0 g
BIS-HFAB (Central Glass Co., Ltd .: reactive fluorine compound) 1.0 g
Excel Hardener HX (Asia Kogyo Co., Ltd .: Hardener) 13.1g
The developer carrying member thus obtained was examined for variations in electrical resistance in the same manner as in Example 1. As a result, the maximum measured value of electrical resistance was 2.0 times the minimum value.
Next, the obtained developer carrying member is incorporated in the developing device shown in FIG. 1, and this developing device is mounted on the image forming apparatus and left for 14 days under high temperature and high humidity. There was no adhesion or contamination. Further, no dimensional change of the developer carrying member was observed. When printing was performed using this image forming apparatus, a good image was obtained.

Effect of the invention

  When used in an electrophotographic system or an electrostatic recording image forming apparatus, the developer carrying member of the present invention is not limited to other members regardless of the reduction in hardness of the member required in connection with higher image quality or colorization. In other words, the variation in electric resistance is small, and sufficient dimensional accuracy can be maintained and good image quality can be realized.

  1 is a schematic cross-sectional view showing an example of an image forming apparatus incorporating a developer carrier of the present invention.   It is a schematic sectional drawing which shows an example of the developing agent carrier of this invention.   It is the schematic which looked at the split mold used by this invention from the upper surface.   It is the schematic which looked at the split mold used by this invention from the side surface.   It is a schematic sectional drawing of the cylindrical mold used by this invention.

DESCRIPTION OF SYMBOLS 1 Developer supply body 2 Developer carrier 3 Developer 4 Developer amount control blade 5 Latent image carrier 6 Elastic body layer 7 Elastic coating layer (barrier layer)
8 Cylindrical insert 9 Runner part 10 Tab 11 Split surface 12 Cylindrical mold 13 End cap 14 Injection hole 15 Core body 16 Elastic coating layer (adhesion prevention layer)
17 Elastic coating layer (barrier layer + adhesion prevention layer)
18 Developer sealing member

Claims (4)

In a developer carrier having a role of developing a latent image by supporting the developer supplied from a developer supply member on the surface and supplying the developer to the latent image formed on the latent image carrier. ,
An elastic body layer mainly made of silicone rubber is formed on the outer periphery of the core body by injection or casting,
Without performing shape processing by grinding or cutting on the outer peripheral surface of the elastic layer, at least one elastic coating layer is formed on the outer periphery,
The outermost layer of the elastic coating layer is a barrier layer for the purpose of preventing migration of low molecular weight contaminants that are bleeds from silicone rubber, and is also an adhesion preventing layer, and includes an acrylic urethane resin and an organic fluorine compound . A developer-carrying member formed from an elastic body containing the organic fluorine compound in an amount of 0.5% by mass or more in the elastic coating layer .
2. The developer carrier according to claim 1, wherein the elastic body layer mainly composed of silicone rubber is a molded body obtained by heat curing an addition reaction type liquid silicone rubber material.
A mold having a recess for fixing a cylindrical insert for forming an outer peripheral surface of the core body and the outer diameter of the elastic body layer, or an end cap for fixing the core body. The developer carrying member according to claim 1 or 2, wherein the developer carrying member is formed by a cylindrical mold for forming an outer peripheral surface having a target outer diameter of the elastic layer.
  A developing device comprising the developer carrying member according to claim 1.

Images