JP5465034B2 - Developing roll - Google Patents

Description

  The present invention relates to a developing roll, and more particularly to a developing roll that can be advantageously used in an image forming apparatus such as a copying machine, a printer, and a facsimile using an electrophotographic system.

  Conventionally, in an image forming apparatus (hereinafter referred to as an electrophotographic apparatus) such as a copying machine, a printer, and a facsimile using an electrophotographic method, when developing an electrostatic latent image on an image carrier (photosensitive drum), A developing roll is used. For example, in an electrophotographic apparatus employing a contact development method, a toner layer is formed on the surface of a developing roll by a toner regulating member, and an electrostatic latent image is formed in a state where the toner layer is held. The electrostatic latent image is developed by rotating in contact with the image carrier (photosensitive drum) in contact with the image carrier (photosensitive drum).

  As the developing rolls as described above, those having various configurations have been conventionally used. For example, a conductive elastic layer, which is a base layer, is formed on the outer peripheral surface of a metallic shaft body, and a liquid material mainly composed of a synthetic resin material is known on the outer peripheral surface of the conductive elastic layer. A developing roll having a two-layer structure in which a coating layer (surface layer) formed by coating and drying is formed is known.

  By the way, in recent years, with respect to electrophotographic equipment, it has been demanded that more excellent durability and higher quality images can be developed. R & D is underway. In particular, in the developing roll, a toner layer is formed on the surface and the developer roll is brought into contact with the image carrier (photosensitive drum), so that it exhibits characteristics suitable for the toner and the image carrier to be used. The development of what you get is underway.

  For example, in an electrophotographic apparatus that employs a low-melting-point toner for the purpose of speeding up and that employs an image carrier made of a relatively flexible material, flexibility is also required for the developing roll. In order to exert flexibility in the development roll having the two-layer structure as described above, it is generally considered to reduce the hardness of the base layer (conductive elastic body layer) and / or the surface layer, but extremely low hardness of the base layer, etc. However, there is a problem in that there is a risk of causing deterioration of the settling resistance. In addition, when the roll surface is flexible, there is a problem that a toner deteriorated by the long-term use adheres to the roll surface and a fogging image is generated.

  Under such circumstances, developing rolls having various configurations have been proposed to solve specific problems (see Patent Documents 1 to 4).

  However, at the present time when the demand for higher durability and higher image quality for electrophotographic equipment is higher than conventional ones, the present inventors, etc., regarding conventional developing rolls including those proposed in the above patent document. As a result of intensive studies, it has been found that the present invention should still be improved, particularly in terms of suppressing toner deterioration and toner filming.

JP 2006-178099 A JP 2008-249985 A Japanese Patent No. 4183216 JP 2002-207362 A

  Here, the present invention has been made in the background of such circumstances, and the problem to be solved is to effectively suppress the deterioration of toner and the occurrence of toner filming and for a long time. Another object of the present invention is to provide a developing roll capable of developing high-quality images.

And in order to solve such a problem advantageously in the present invention, the base layer, the intermediate layer, and the surface layer are sequentially and integrally formed on the outer peripheral surface of the shaft body from the inner side to the outer side in the roll radial direction. In the developing roll formed by laminating, 1) the base layer is formed of a base layer forming material mainly composed of silicone rubber, and 2) the intermediate layer includes a thermoplastic urethane elastomer and a fluorosurfactant. 3) The glass transition temperature is formed according to a roll coating method using a liquid intermediate layer forming material containing at least 3), and the surface layer is composed of at least one of acrylic silicone resin, urethane silicone resin and acrylic resin. Using a liquid surface layer forming material containing at least a synthetic resin material having a temperature of 30 to 50 ° C. and a fluorosurfactant. Are formed in accordance with the law, at 4) roll surface, MD-1 hardness of from 30.0 to 45.0 °, and, said the Martens hardness of 0.86~1.30N / mm ² The developing roll is a gist thereof.

  In one preferred embodiment of the developing roll according to the present invention, the base layer has a JIS-A hardness of 25 to 35 °.

In another preferred embodiment of the developing roll of the present invention, the intermediate layer has a Martens hardness of 0.15 to 4.00 N / mm ² .

  Furthermore, in one of desirable embodiments of the developing roll of the present invention, the thickness of the surface layer is 0.10 to 2.00 μm.

  Furthermore, in another preferred embodiment of the developing roll of the present invention, roughness forming particles are blended in the intermediate layer forming material.

  Thus, in the developing roll according to the present invention, the base layer, the intermediate layer, and the surface layer are each formed using a predetermined material, and MD-1 hardness and Martens hardness measured on the roll surface. However, even when the developer roll is incorporated in an electrophotographic apparatus and used for a long period of time, the toner deterioration and toner filming are effectively generated. Thus, a high-quality image can be obtained over a long period of time.

  Further, among the developing rolls according to the present invention, in particular, those having an intermediate layer formed of an intermediate layer forming material in which the particles for roughness formation are blended have an uneven shape on the surface of the intermediate layer. Formed. Since the surface layer obtained by applying a surface layer forming material to such a surface according to a roll coating method and drying it is formed with a uniform thickness so as to follow the uneven shape of the surface of the intermediate layer, In addition to excellent properties, the local hardness difference on the roll surface is reduced, and the developing roll can effectively suppress the toner deterioration and toner filming.

It is an axis perpendicular cross-section explanatory drawing which shows an example of the image development roll according to this invention.

  FIG. 1 schematically shows an exemplary embodiment of a developing roll according to the present invention in a cross section perpendicular to the axis. As shown in FIG. 1, the developing roll 10 includes a base layer 14, an intermediate layer 16, and an outer layer on a metal shaft body (core metal) 12 from the inner side to the outer side in the roll radial direction. Each surface layer 18 is integrally laminated with a predetermined thickness.

And in such a developing roll 10, while the base layer 14, the intermediate | middle layer 16, and the surface layer 18 are each formed with the predetermined material, MD-1 hardness and Martens hardness measured in the roll surface are The MD-1 hardness is within a range of 30.0 to 45.0 °, and the Martens hardness is within a range of 0.86 to 1.30 N / mm ^2. There is a big feature.

  That is, two hardnesses (MD-1 hardness and Martens hardness) having different measurement areas on the roll surface are within predetermined ranges, so that the base layer, the intermediate layer, and the surface layer are formed of characteristic materials. In combination with this, the developing roll 10 according to the present invention can effectively suppress toner deterioration and toner filming and can develop high-quality images over a long period of time. It has become.

Here, the developing roll having a surface MD-1 hardness of more than 45.0 ° promotes the deterioration of the toner, and the deteriorated toner may adhere to the roll surface and be fixed (toner filming may occur). . When toner filming occurs, so-called “fogging” (if originally intended) occurs due to the occurrence of image roughness or a decrease in toner chargeability corresponding to the portion of the roll surface where toner filming has occurred. The phenomenon that the toner adheres to the portion where the toner should not adhere is also likely to occur. On the other hand, in the developing roll having a surface MD-1 hardness of less than 30.0 °, the toner releasability is poor and the toner tends to remain on the roll surface. There is a risk that toner filming may occur due to deterioration. Therefore, in the developing roll 10 which concerns on this invention, MD-1 hardness of a roll surface shall be 30.0-45.0 degrees. Similarly, when the Martens hardness on the roll surface is too high or too low, toner filming may occur. Therefore, in the present invention, the Martens hardness on the roll surface is 0.86 to 1.30 N / It is within the range of mm ² .

  In the present specification and claims, the MD-1 hardness of the roll surface means that the MD-1 hardness is measured at 9 points in total in the circumferential direction at 3 points respectively at both ends and the center of the roll. , Averaged values obtained. The Martens hardness on the roll surface is measured according to ISO-14577 on the roll surface.

  As described above, the developing roll 10 according to the present invention has the surface MD-1 hardness and Martens hardness within predetermined ranges, respectively. In addition, the base layer 14, the intermediate layer 16, and the surface layer 18 Each is made of a characteristic material.

  First, the base layer 14 is formed of a base layer forming material whose main component is silicone rubber. This is because silicone rubber is relatively excellent in electrical conductivity and resistance to settling. As long as the object of the present invention is not impaired, the silicone rubber is prepared by blending a conductive agent such as carbon black, silicone oil such as dimethyl silicone oil, and various conventionally known additives. It is also possible to use a material as the base layer forming material.

  In the base layer 14 formed of such a base layer forming material, if the JIS-A hardness is too high, the MD-1 hardness and Martens hardness of the finally obtained developing roll 10 may be too high. On the other hand, if the JIS-A hardness of the base layer 14 is too low, the MD-1 hardness or the like of the developing roll 10 may be too low. Accordingly, in the present invention, the JIS-A hardness of the base layer 14 is preferably in the range of 25 to 35 °, and a base layer forming material that satisfies this is used. Here, the JIS-A hardness of the base layer 14 refers to JIS-A for any three points on the sheet of φ100 (thickness: 10 mm) produced using the base layer forming material constituting the base layer. The hardness is measured and the measurement results are averaged. Of course, it is possible to use two or more types of silicone rubbers together so that the JIS-A hardness is in the range of 25 to 35 °.

  Next, the intermediate layer 16 is formed of a liquid intermediate layer forming material containing at least a thermoplastic urethane elastomer and a fluorosurfactant. Since the fluorosurfactant is contained, when the coating is performed according to the roll coating method described later, the dripping of the intermediate layer forming material as the coating liquid is made uniform, and the thickness of the intermediate layer 16 is relatively This makes it possible to form a good image.

  Here, examples of the thermoplastic urethane elastomer include caprolactone type, adipate type, and ether type urethane elastomers. Among these, caprolactone type urethane elastomer is preferable from the viewpoint of ensuring high mechanical strength and elastic recovery. Moreover, from a viewpoint of ensuring coatability, a relatively large molecular weight is preferable, and specifically, one having a molecular weight of 10,000 to 500,000 is advantageously used.

  Examples of fluorosurfactants include GF-150 (trade name, manufactured by Toagosei Co., Ltd.), MegaFuck F-494, and Megafuck F-482 (both trade names, manufactured by DIC Corporation). I can do it. In addition, generally a fluorine-type surfactant is mix | blended with an intermediate | middle layer forming material in the quantitative ratio which will be 0.1-3 weight part with respect to 100 weight part of a thermoplastic urethane elastomer.

  Furthermore, it is preferable to mix roughness forming particles in the intermediate layer forming material. By blending such particles for forming the roughness, the finally obtained developing roll 10 has excellent toner transportability, suppresses the occurrence of a local hardness difference on the roll surface, and causes toner deterioration and toner filming. Generation | occurrence | production can be suppressed more effectively.

  The material of such roughness forming particles is not particularly limited, and is made of acrylic resin, urethane resin, silica, polyamide resin, fluororesin, urea resin, polymethyl methacrylate, etc. that have been widely used conventionally. Particles can be used. An intermediate layer comprising particles of these materials having an average particle diameter of 1.5 to 30 μm in a quantitative ratio of 3 to 50 parts by weight with respect to 100 parts by weight of the thermoplastic urethane elastomer. It is preferable to mix with the forming material.

  In order to make the intermediate layer forming material liquid, generally, an organic solvent such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), or toluene is used. In addition, when preparing the intermediate layer forming material, various additives such as a conductive agent and a crosslinking agent can be blended in addition to the above-described thermoplastic urethane elastomer and the like as long as the object of the present invention is not impaired. It is.

In the intermediate layer 16 formed of the above-described intermediate layer forming material, if the Martens hardness is too high, the MD-1 hardness and Martens hardness of the finally obtained developing roll 10 may be too high. If the Martens hardness of the intermediate layer 16 is too low, the MD-1 hardness of the developing roll 10 may be too low. Accordingly, in the present invention, the Martens hardness of the intermediate layer 16 is preferably in the range of 0.15 to 4.00 N / mm ² , and an intermediate layer forming material that satisfies this is used. In addition, the Martens hardness of the intermediate layer 16 means that the intermediate layer forming material constituting the intermediate layer is measured according to ISO-14577 under the conditions of a test force of 1 mN and a holding time of 5 seconds. .

  And the surface layer 18 is a liquid containing at least one of a synthetic resin material having a glass transition temperature of 30 to 50 ° C. and a fluorosurfactant, which is made of at least one of acrylic silicone resin, urethane silicone resin and acrylic resin. The surface layer forming material is used.

  The acrylic silicone resin, urethane silicone resin and acrylic resin used in the present invention are conventionally known, and any glass transition temperature of 30 to 50 ° C. can be used. is there. Moreover, even if it is an acrylic silicone resin etc. whose glass transition temperature is outside the range of 30-50 degreeC, the glass transition temperature of the synthetic resin material which consists of them together using other acrylic silicone resin etc. from which glass transition temperature differs Can be used in the present invention if it falls within the range of 30 to 50 ° C. Here, the glass transition temperature means that measured by differential scanning calorimetry (DSC). Thus, by using a synthetic resin material having a glass transition temperature within a predetermined range, the obtained surface layer has sufficient hardness even if it is thin.

  In addition, since the surface layer forming material also contains a fluorine-based surfactant, when coating is performed according to the roll coating method described later, the dripping of the surface layer forming material as the coating liquid is made uniform, and the surface layer 18 Since the thickness is relatively uniform, good image formation is possible. Further, in the present invention, since the fluorosurfactant blended in the surface layer forming material can provide an advantageous effect even when the blending amount is relatively small, charging of the toner by the fluorosurfactant is possible. It is possible to suppress a decrease in property. The fluorosurfactant is preferably blended in the surface layer forming material at a quantitative ratio of 0.1 to 3 parts by weight with respect to 100 parts by weight of the synthetic resin material described above. In addition, as a fluorine-type surfactant, the thing similar to what was shown previously can be used.

  In the surface layer forming material, a compound having a functional group capable of reacting with the synthetic resin material is preferably blended as a crosslinking agent. By blending such a compound, the cross-linking of the synthetic resin material can proceed effectively, and the adhesion between the intermediate layer 16 and the surface layer 18 as a base can be improved. Specifically, it is preferable to blend isocyanate, melamine resin, xylene resin, epoxy resin, and the like as a crosslinking agent. In the case of blending isocyanate, the isocyanate component is used with respect to 100 parts by weight of the synthetic resin material. Is blended into the surface layer-forming material in a quantitative proportion such that the amount of 20 to 50 parts by weight.

  In addition, the surface layer forming material can be blended with silicone oil in order to improve the releasability on the surface of the developing roll 10.

  Furthermore, an organic solvent such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), or toluene can be used to make the surface layer forming material liquid.

  Since the surface layer 18 obtained using the surface layer forming material composed of each component described above can enjoy the effects of the present invention even if it is relatively thin, in the present invention, the thickness of the surface layer is preferably The thickness is set to 0.10 to 2.00 μm.

  The base layer forming material, the intermediate layer forming material, and the surface layer forming material described above are prepared according to the same method as in the past.

  By the way, the developing roll 10 according to the present invention is manufactured, for example, according to the following method.

  First, the shaft body 12 is prepared. However, the shaft body 12 is not particularly limited as long as it is made of a conductive metal. Iron, stainless steel (SUS), free-cutting steel (SUM) ) Etc. can be illustrated. Further, the shaft body 12 may be subjected to a plating treatment or the like, and an adhesive, a primer, or the like may be applied to the outer peripheral surface as necessary. In addition, the shape of the shaft body 12 may be a pipe-shaped hollow cylindrical body other than the rod-shaped solid body as shown in FIG.

  Subsequently, the formation material of each layer mentioned above is prepared, and first, the base layer 14 is formed on the outer peripheral surface of the shaft body 12 using the base layer formation material. Specifically, the shaft body 12 is set in a molding cavity of a cylindrical mold, and after the base layer forming material is cast into the space of the cylindrical mold, the base layer forming material is crosslinked by heating. . As a result, a base roll in which the base layer 14 is integrally formed on the outer peripheral surface of the shaft body 12 is obtained.

  Further, a liquid intermediate layer forming material is applied to the surface of the base roll (the outer peripheral surface of the base layer 14) according to a roll coating method. Here, the roll coating method means a method of supplying a coating material on the surface of an object to be coated using a coating roll to form a coating film. Various methods are known as the roll coating method. For example, the following methods are known. First, the object to be coated (base roll) is arranged so that its axial direction is vertical, while the coating roll is arranged so that its axial direction is horizontal and the outer peripheral surface of the object to be coated (base roll) Place it so that it is pressed against. Then, the object to be coated (base roll) and the coating roll are rotated around their respective axes, and the object to be coated (base) is supplied while continuously supplying the coating material (interlayer forming material) to the coating roll. The coating material (intermediate layer forming material) is applied to the outer peripheral surface of the object to be coated (base roll) by moving the coating roll in one direction up and down with respect to the roll). A coating film made of an intermediate layer forming material is formed.

  In carrying out such a roll coating method, a roll coating apparatus disclosed in Japanese Patent No. 2651554, Japanese Patent Publication No. 6-36901, Japanese Patent Application Laid-Open No. 2009-74598, or the like is advantageously used.

  According to the roll coating method, a coating film made of the intermediate layer forming material is formed, and the coating film is heated as necessary to form the intermediate layer 14. Further, a liquid surface layer is formed on the surface of the intermediate layer 14. The forming material is applied according to a roll coating method. And the target image development roll 10 is obtained by heating as needed.

  In the developing roll 10 thus obtained, the base layer, the intermediate layer, and the surface layer are each formed using a predetermined material, and the MD-1 hardness and Martens hardness measured on the roll surface are as follows: Since each of the developing rolls 10 is configured within a predetermined range, even when the developing roll 10 is incorporated in an electrophotographic apparatus and used for a long period of time, toner deterioration and toner filming are effectively suppressed. Therefore, a high-quality image can be obtained over a long period of time.

  Some examples of the present invention will be shown below to clarify the present invention more specifically. However, the present invention is not limited by the description of such examples. Needless to say. In addition to the following examples, the present invention includes various changes and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention, in addition to the specific description described above. It should be understood that improvements and the like can be added.

-Preparation of base layer forming material-
Prepare three types of commercially available silicone rubber (trade name: KE1379, X-34-264, X-34-387, manufactured by Shin-Etsu Chemical Co., Ltd.), and use one or two of these to create five types The base layer forming material (I to V) was used. The JIS-A hardness of each base layer forming material is shown in Table 1 below.

-Preparation of intermediate layer forming material-
Each component was blended at a ratio shown in Table 2 below with respect to 100 parts by weight of methyl ethyl ketone, and mixed and stirred to prepare five kinds of intermediate layer forming materials. Table 2 below shows the Martens hardness of each intermediate layer forming material. In the preparation, the following thermoplastic urethane elastomers were used.
・ Thermoplastic urethane elastomer: NIPPOLAN 5199 (trade name),
Made by Nippon Polyurethane Industry Co., Ltd. ・ Carbon black: # 5530 (trade name), made by Cabot Japan Co., Ltd. ・ Crosslinking agent A: Super Becamine P-138 (trade name), made by DIC Corporation ・ Crosslinking agent B: Burnock D750 ( Product name), manufactured by DIC Corporation ・ Roughness-forming particles A: SGP-50C (trade name), manufactured by Soken Chemical Co., Ltd. ・ Roughness-forming particles B: Cyrossphere C-1510 (trade name), Fuji Silysia Chemical -Co., Ltd.-Roughness-forming particles C: Dimic beads UCN5150D (trade name), manufactured by Dainichi Seika Kogyo Co., Ltd.-Fluorosurfactant: Aron GF-150 (trade name), manufactured by Toagosei Co., Ltd.

-Preparation of surface layer forming material-
Each component was blended in the proportions shown in Table 3 below, mixed and stirred to prepare 17 types of surface layer forming materials. In the preparation, the following acrylic silicone resins and the like were used.
• Acrylic silicone resin A: Cymac XS2701 (trade name), manufactured by Toagosei Co., Ltd. • Acrylic silicone resin B: S-1500LS (trade name), manufactured by Toagosei Co., Ltd. • Acrylic silicone resin C: Reseta GS1015 (trade name), Made by Toagosei Co., Ltd. ・ Acrylic silicone resin D: Reseta GS1200 (trade name), made by Toagosei Co., Ltd. ・ Acrylic silicone resin E: Saimak US-270 (trade name), made by Toagosei Co., Ltd. D750 (trade name), manufactured by DIC Corporation ・ Carbon black: # 5530 (trade name), manufactured by Cabot Japan Corporation ・ Fluorosurfactant: Aron GF-150 (trade name), manufactured by Toagosei Co., Ltd.

-Production of developing roll-
First, a metal shaft body (core metal, diameter: 8 mm) was prepared, and an adhesive was applied to the outer peripheral surface of the shaft body. Next, a cored bar was set in the molding cavity of the cylindrical mold, and after the base layer forming material was cast into the gap in the molding cavity, the mold was covered and heated at 180 ° C. for 5 minutes. Thereafter, the mold was removed, and a base layer was integrally formed on the outer peripheral surface of the shaft body.

  After the intermediate layer forming material was applied to the outer peripheral surface of the base layer according to the roll coating method, the intermediate layer was provided on the outer peripheral surface of the base layer by drying and heat treatment. Furthermore, after the surface layer forming material is applied to the outer peripheral surface of the intermediate layer according to the roll coating method, drying and heat treatment are performed to develop a three-layer structure (base layer, intermediate layer and surface layer) as shown in FIG. A roll was produced. A total of 62 types of developing rolls (Examples 1 to 30 and Comparative Examples 1 to 32) were produced by changing the materials used when forming each layer. About each obtained developing roll, MD-1 hardness and Martens hardness of the surface were measured. Tables 4 to 7 below show the MD-1 hardness and Martens hardness of each developing roll, and the materials of each layer used when producing each developing roll.

  Each of the obtained developing rolls was incorporated into a commercially available laser beam printer (trade name: LBP5700, manufactured by Canon Inc.), and 8000 test patterns were printed (endurance test). Thereafter, the following evaluation was performed.

-Toner filming evaluation-
After the durability test described above, the presence or absence of toner filming on the surface of the developing roll was visually observed. The observation results were evaluated according to the following criteria. An evaluation result is combined with following Table 4-Table 7, and is shown.
○: No toner filming occurred.
Δ: Mild toner filming that does not hinder actual use is observed.
X: Toner filming that is obvious enough to cause trouble in actual use is recognized.

-Fog evaluation-
After the durability test described above, a test pattern was printed again, and the obtained image was visually observed. The observation results were evaluated according to the following criteria. An evaluation result is combined with following Table 4-Table 7, and is shown.
○: No fogging phenomenon (where toner is flying where there is no image).
X: A fog phenomenon is recognized.

  As is apparent from the results of Tables 4 to 7, it is recognized that the development roll according to the present invention can effectively suppress the occurrence of toner filming and fogging even after the durability test. It was.

DESCRIPTION OF SYMBOLS 10 Developing roll 12 Shaft body 14 Base layer 16 Intermediate layer 18 Surface layer

Claims (5)

On the outer peripheral surface of the shaft body, from the inner side to the outer side in the roll radial direction, the base layer, the intermediate layer, and the surface layer are sequentially and integrally laminated,
The base layer is formed of a base layer forming material mainly composed of silicone rubber,
The intermediate layer is formed according to a roll coating method using a liquid intermediate layer forming material containing at least a thermoplastic urethane elastomer and a fluorosurfactant,
The surface layer is a liquid surface layer comprising at least one of a synthetic resin material having a glass transition temperature of 30 to 50 ° C. and a fluorosurfactant, comprising at least one of acrylic silicone resin, urethane silicone resin and acrylic resin. It is formed according to the roll coating method using the forming material,
A developing roll having an MD-1 hardness of 30.0 to 45.0 ° and a Martens hardness of 0.86 to 1.30 N / mm ² on the roll surface.   The developing roll according to claim 1, wherein the base layer has a JIS-A hardness of 25 to 35 °. The developing roll according to claim 1, wherein the intermediate layer has a Martens hardness of 0.15 to 4.00 N / mm ² .   The developing roll according to claim 1, wherein the surface layer has a thickness of 0.10 to 2.00 μm. The developing roll according to claim 1, wherein roughness forming particles are blended in the intermediate layer forming material.

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