JP2015225241A - Member for electrophotography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a member for electrophotography that can sufficiently suppress a deterioration of toner and filming.SOLUTION: A member for electrophotography R has a surface layer 1 and is used for an electrophotographic device. The member for electrophotography R (1) has the surface layer 1 having a thickness of 12 μm or less, (2) has the surface of the member having an MD-1 hardness of 50° or less, (3) has the surface of the surface layer 1 having a coefficient of kinetic friction of 1.2 or less, and (4) in a primary relational expression obtained from the relationship between a vertical load W applied to the surface of the surface layer 1 by a contact maker and a friction force F generated between the surface of the surface layer 1 and the contact maker, satisfies the state where the friction force Fis 0 g or less when the vertical load W is 0 g.

Description

  The present invention relates to an electrophotographic member.

  Conventionally, electrophotographic apparatuses such as electrophotographic copying machines, printers, and facsimiles are known. These electrophotographic apparatuses form an image through processes such as latent image formation by image data exposure on a charged photoreceptor, development, transfer to a transfer medium, and fixing. Therefore, various electrophotographic members are incorporated in the apparatus in order to realize these processes.

  For example, a roll-shaped charging member is incorporated to charge the surface of the photoreceptor. In addition, a roll-shaped developing member is incorporated in order to attach a toner to the electrostatic latent image formed on the surface of the photosensitive member to form a visible image. Also, recently, each toner image formed by a plurality of photoconductors by color is primarily transferred onto the belt surface, and the toner images of each color are superimposed and transferred onto a sheet of paper. It is used.

  As the electrophotographic member, specifically, for example, Patent Document 1 includes a charge imparting layer, a base layer, and an elastic intermediate layer formed between the charge imparting layer and the base layer. A developing roll is disclosed in which the contact angle of water on the surface of the elastic intermediate layer is smaller than that of water on the surface of the base layer.

JP 2001-66877 A

  In recent years, there has been an increasing demand for higher image quality and improved durability in an electrophotographic apparatus in which the above-described electrophotographic member is incorporated. Accordingly, electrophotographic members are required to suppress toner deterioration at a high level in order to contribute to high image quality of the electrophotographic apparatus. In addition, in order to improve the durability of the electrophotographic apparatus, it is required to suppress the filming phenomenon in which dirt components such as unnecessary toner and carrier cover the member surface at a high level.

  As a method of suppressing toner deterioration in the electrophotographic member, a method of improving the flexibility of the entire member can be considered. However, in this method, the contact area with the mating member that is in sliding contact with the surface of the member increases, so that the slipperiness of the surface of the member is deteriorated, and thus the toner is easily deteriorated. Therefore, it is difficult for the above method to sufficiently suppress toner deterioration. In addition, when the contact area with the mating member increases as described above, the contact area with dirt components such as toner and carrier also increases. For this reason, the dirt component easily adheres to the surface of the member, and the attached dirt component adheres and filming is likely to occur.

  Thus, it is difficult to obtain an electrophotographic member capable of sufficiently suppressing toner deterioration and filming by simply improving the flexibility of the entire member.

  The present invention has been made in view of the above-described background, and an object of the present invention is to provide an electrophotographic member capable of sufficiently suppressing toner deterioration and filming.

One aspect of the present invention is a member for electrophotography having a surface layer and used for an electrophotographic apparatus,
The electrophotographic member satisfies the following (1) to (4).
(1) Thickness of the surface layer: 12 μm or less (2) MD-1 hardness of the member surface: 50 ° or less (3) Dynamic friction coefficient of the surface layer surface: 1.2 or less (4) Addition to the surface layer by a contactor In the primary relational expression obtained from the relationship between the vertical load W and the friction force F generated between the surface of the surface layer and the contact, the friction force F ₀ when the vertical load W is 0 g is 0 g or less.

  The electrophotographic member satisfies the above (1). Therefore, even if the surface layer is designed to be relatively hard in order to improve the slipperiness of the surface layer surface and to improve the separation of dirt components such as toner and carrier adhered to the surface layer surface, Since the thickness is small, the surface layer makes it difficult for the toner to be stressed and the toner is difficult to deteriorate.

  The electrophotographic member satisfies the above (2). Therefore, in the electrophotographic member, since the hardness of the entire member is lowered, the toner is hardly subjected to stress and the toner is not easily deteriorated.

  The electrophotographic member satisfies the above (3). Therefore, even if the contact area with the mating member that is in sliding contact with the surface of the surface layer increases due to a decrease in the hardness of the entire member by satisfying the above (2), the electrophotographic member is located between the surface of the surface layer and the mating member. Since the frictional force is reduced, the slipperiness of the surface of the surface layer is improved. Therefore, the toner of the electrophotographic member is hardly deteriorated by this.

  Therefore, the electrophotographic member can sufficiently suppress toner deterioration.

  The electrophotographic member satisfies the above (4). Therefore, in the electrophotographic member, even if a dirt component such as a toner or a carrier adheres to the surface layer surface, the dirt component tends to be separated from the surface layer surface. Therefore, even if the contact area between the surface layer surface and the soil component increases due to the decrease in the hardness of the entire member by satisfying the above (2), the electrophotographic member is difficult to adhere the soil component to the surface layer surface. Become.

  Therefore, the electrophotographic member can sufficiently suppress filming.

  Therefore, according to the present invention, it is possible to provide an electrophotographic member capable of sufficiently suppressing toner deterioration and filming.

It is an explanatory diagram for describing how to obtain the frictional force F _0. FIG. 3 is an explanatory diagram schematically showing an electrophotographic member of Example 1. It is the figure which showed the III-III cross section in FIG.

  The electrophotographic member is a member used in an electrophotographic apparatus. Specific examples of the electrophotographic apparatus include image forming apparatuses such as copiers, printers, facsimile machines, multifunction machines, and on-demand printers that employ an electrophotographic system using a charged image.

  Specifically, the electrophotographic member can be a developing member, a charging member, or a transfer member incorporated in an electrophotographic image forming apparatus. As the transfer member, specifically, an intermediate transfer member can be exemplified. The intermediate transfer member is for primary transfer of the toner image carried on the photosensitive member to the member, and then secondary transfer of the toner image from the member to a transfer material such as paper.

  When the electrophotographic member is used as a developing member, a developing member capable of sufficiently suppressing toner deterioration and filming is obtained. When the electrophotographic member is used as a charging member, a charging member that can sufficiently suppress toner deterioration and filming can be obtained. When the electrophotographic member is used as a transfer member, a transfer member capable of sufficiently suppressing toner deterioration and filming is obtained.

  Here, the electrophotographic member satisfies the above (1) to (4). Hereinafter, the technical significance of the above (1) to (4) will be described.

(1) Surface layer thickness: 12 μm or less The surface layer thickness affects the MD-1 hardness of the member surface and the dynamic friction coefficient of the surface layer surface. Therefore, it is necessary to define the thickness of the surface layer as a premise for defining the MD-1 hardness of the member surface and the dynamic friction coefficient of the surface layer surface. Further, when the thickness of the surface layer exceeds 12 μm, when the surface layer is designed to be relatively hard in order to improve the slipperiness of the surface layer surface and improve the separation of dirt components such as toner and carrier attached to the surface layer surface, Since the thickness of the surface layer is large, the toner is easily subjected to stress by the surface layer, and the toner is easily deteriorated. Therefore, the thickness of the surface layer is specified to be 12 μm or less. The thickness of the surface layer can be preferably 11 μm or less.

  When the thickness of the surface layer is excessively thin, the film formability of the surface layer is deteriorated. Therefore, the thickness of the surface layer is preferably 0.01 μm or more, more preferably 0.1 μm or more, and further preferably 1 μm or more.

  The thickness of the surface layer can be obtained by observing the cross section of the surface layer using a scanning electron microscope and obtaining an average value of the measured values of the surface layer thickness. Specifically, when the electrophotographic member has a roll shape, the thickness of the surface layer is an average value of each value measured from the center part in the roll axis direction and the both end faces to the center part side in the inside of 20 mm. is there. Further, when the electrophotographic member has a belt shape, the thickness of the surface layer is an average value of each value measured from the central part in the belt width direction and both end faces to the central part side within 20 mm. When surface roughness is formed on the surface of the surface layer due to the addition of roughness forming particles on the surface of the surface layer, the thickness of the concave portion is measured.

(2) MD-1 hardness of member surface: 50 ° or less In the above electrophotographic member, the member surface coincides with the surface of the surface layer. The MD-1 hardness of the member surface is a physical property value indicating the hardness of the entire member. That is, when the electrophotographic member has a lower layer such as an elastic layer below the surface layer, the MD-1 hardness of the member surface is not only the surface layer but also the hardness of the member including the lower layer. When the MD-1 hardness of the member surface exceeds 50 °, the hardness of the entire member increases, so that the toner is easily subjected to stress and the toner is likely to be deteriorated. Therefore, the MD-1 hardness of the member surface is specified to be 50 ° or less.

  The MD-1 hardness of the surface of the member is preferably 48 ° or less, more preferably 46 ° or less, from the viewpoint of easily suppressing toner deterioration. If the MD-1 hardness of the member surface is excessively small, the contact area with the mating member that is in sliding contact with the surface layer surface becomes excessive, which is disadvantageous for improving the slipperiness of the surface layer surface and suppressing filming. Moreover, it is difficult to manufacture an electrophotographic member having an MD-1 hardness of the member surface that is excessively small. Therefore, from these viewpoints, the MD-1 hardness of the member surface can be 25 ° or more. The MD-1 hardness of the member surface can be preferably 30 ° or more, more preferably 35 ° or more.

  The MD-1 hardness of the member surface is measured using a spring type hardness tester (manufactured by Kobunshi Keiki Co., Ltd., micro rubber hardness meter / MD-1 type) adopting a cantilever leaf spring type load system. The surface of the surface layer is brought into contact with the tip of the push needle of the tester, and the surface is pressed vertically with a load of 33.85 g, and the scale is immediately read. Specifically, when the electrophotographic member has a roll shape, the MD-1 hardness of the member surface is 20 mm from the central portion and both end surfaces in the roll axial direction to the central portion side in the portion where the surface layer is formed. It is the average value of each value measured internally. Further, when the electrophotographic member has a belt shape, the MD-1 hardness of the member surface is an average value of each value measured from the central part in the belt width direction and both end faces to the central part side within 20 mm. It is.

(3) Dynamic friction coefficient on the surface layer surface: 1.2 or less The dynamic friction coefficient on the surface layer surface is a physical property value closely related to the slipperiness of the surface layer surface. When the dynamic friction coefficient of the surface layer exceeds 1.2, when the contact area with the mating member in sliding contact with the surface layer surface increases due to the decrease in the hardness of the entire member by satisfying the above (2), the surface layer surface and the mating surface The frictional force between the members becomes too large. As a result, the slipperiness of the surface of the surface layer is reduced, and the toner is likely to deteriorate. Therefore, the dynamic friction coefficient of the surface layer surface is specified to be 1.2 or less.

  The dynamic friction coefficient of the surface layer surface is preferably 1.18 or less, and more preferably 1.15 or less, from the viewpoint of improving the slipperiness of the surface layer surface. The dynamic friction coefficient on the surface of the surface layer is preferably 0.1 or more, more preferably 0.2 or more, from the viewpoint of ensuring transportability by maintaining an appropriate frictional force against the toner.

  The dynamic friction coefficient on the surface of the surface layer can be obtained as follows. Using a static / dynamic friction coefficient measuring instrument (“Tribostar 500” manufactured by Kyowa Interface Science Co., Ltd.), a vertical load W of 50 g was applied to the surface of the surface layer with a contact made of a steel ball having a diameter of 3 mm. It can be obtained by calculating a value (initial value) of F / W from a frictional force F generated between the surface of the surface layer and the contact by moving 1 cm in the horizontal direction at 0.5 mm / second.

(4) Friction when the vertical load W is 0 g in the primary relational expression obtained from the relationship between the vertical load W applied to the surface of the surface by the contact and the frictional force F generated between the surface of the surface and the contact. Force F ₀ : 0 g or less The value of the frictional force F ₀ is a physical property value closely related to the separation property of the soil component from the surface layer surface when the soil component such as toner or carrier adheres to the surface layer surface. Conventionally, a contact angle of a liquid such as dodecane or water on the surface of the surface layer is used as a physical property value related to the releasability of substances attached to the surface of the surface layer. However, according to the study by the present inventors, there is not much interrelationship between the contact angle and the separation property of the stain component from the surface layer when the stain component such as toner or carrier adheres to the surface layer surface. In the above contact angle, it has been found that it is difficult to correctly evaluate the separation property of the dirt component adhering to the surface of the surface layer. On the other hand, the value of the frictional force F ₀ has a high correlation with the separation property of the dirt component from the surface layer surface when the dirt component such as toner or carrier adheres to the surface layer surface. This is presumably because the value of the frictional force F ₀ represents the adhesion force (interaction) between the soil component adhering to the surface layer surface and the surface layer surface.

When the value of the frictional force F ₀ exceeds 0 g, when a dirt component such as toner or carrier adheres to the surface layer surface, the dirt component is difficult to separate from the surface layer surface. Therefore, when the contact area between the surface layer surface and the soil component increases due to the decrease in the hardness of the entire member due to satisfying the above (2), the soil component tends to adhere to the surface layer surface and filming is likely to occur. . Therefore, to define the value of the frictional force F ₀ below 0 g. The value of the frictional force F ₀ is preferably less than 0 g, more preferably −0.5 g or less, still more preferably −1 or less, and even more preferably, from the viewpoint that filming is easily suppressed. -1.5 or less.

The value of the frictional force F ₀ may be obtained as follows. Using a static / dynamic friction coefficient measuring instrument (“Tribostar 500” manufactured by Kyowa Interface Science Co., Ltd.), a vertical load W of 10 g was applied to the surface of the surface with a contact made of a steel ball having a diameter of 3 mm, and the surface layer was moved in this state. is 1cm moved horizontally in 7.5 mm / sec, measuring the frictional force _{F 10} generated between the surface layer surface and the contact, the frictional force _{F 50} similarly by changing the vertical load W to 50g, respectively. Then, as shown in FIG. 1, a straight line passing through two points of coordinates (vertical load W [g], friction force F [g]) = (10, F ₁₀ ) and (50, F ₅₀ ) is obtained, and the straight line The value of the frictional force F ₀ can be obtained by obtaining the frictional force when the vertical load W at 0 is 0 g, that is, the value of the intercept in the straight line.

  The relationship between the friction force F, the friction coefficient μ, and the vertical load W is generally known as F = μW. However, when the measurement is performed as described above, an intercept is present. Therefore, even if the vertical load W = 0 g, it is considered that some force exists between the surface layer surface and the contact.

  In the electrophotographic member, the surface layer can be specifically configured to have a matrix polymer that forms a skeleton of the surface layer and a surface modifier contained in the matrix polymer.

  As a matrix polymer, various resin and rubber | gum (an elastomer is also included, it abbreviate | omits below) can be used, for example. As the surface modifier, for example, a surface modifier made of a copolymer containing F element and Si element in the molecule can be used. Note that the F element is derived from a fluorine-containing group included in the copolymer, and the Si element is derived from a silicone group included in the copolymer. As for surface layer, various additives such as conductive agent (electronic conductive agent, ionic conductive agent), cross-linking agent, cross-linking aid, plasticizer, flame retardant, filler, roughness forming particles, etc., are included in the matrix polymer as necessary. Can be contained.

  In addition to the surface layer, the electrophotographic member may have an elastic layer in contact with the inner surface of the surface layer.

  In this case, mainly by adjusting the surface layer, the elastic layer can be used to adjust the hardness of the entire member while optimizing the slipperiness of the surface layer surface and the separation of dirt components such as toner and carrier adhering to the surface layer. The electrical resistance can be adjusted. Therefore, in this case, the functions of the respective layers are sufficiently exhibited, so that an electrophotographic member that can sufficiently suppress toner deterioration and filming can be obtained.

  Specifically, the elastic layer can be mainly made of various rubbers and resins. Further, the elastic layer can contain various additives such as a conductive agent (electronic conductive agent and ionic conductive agent), a crosslinking agent, a crosslinking aid, a plasticizer, a flame retardant, and a filler, if necessary.

  Specifically, the electrophotographic member includes, for example, (a) a shaft body, an elastic layer formed along the outer peripheral surface of the shaft body, and a surface layer formed along the outer peripheral surface of the elastic layer. (B) a configuration having a base layer formed in a cylindrical shape and a surface layer formed along the outer peripheral surface of the base layer, (c) a base layer formed in a cylindrical shape, and an outer peripheral surface of the base layer It can be set as the structure etc. which have the formed elastic layer and the surface layer formed along the outer peripheral surface of an elastic layer. The configuration (a) is suitable as a developing member or charging member having a roll shape, and the configurations (b) and (c) are suitable as a transfer member having a belt shape.

  The electrophotographic member can have a shape such as a roll shape or a belt shape. The electrophotographic member preferably has a roll shape.

  In this case, there is an advantage that it can be easily applied to various electrophotographic members in contact with the toner.

  In the presence of toner, the electrophotographic member can be used in a state where another mating member used in the electrophotographic apparatus is in contact with the surface of the surface layer, more specifically, in a slidable contact state. Examples of the mating member include a blade member and a roll member disposed around the electrophotographic member. When the mating member is in sliding contact with the surface of the surface layer, the contact area between the surface of the surface layer and the mating member increases. However, the electrophotographic member satisfies the above (3), the frictional force between the surface layer surface and the counterpart member is reduced, and the surface layer surface has good slipperiness. Therefore, the electrophotographic member can effectively suppress toner deterioration even when the contact area between the surface layer surface and the mating member increases due to the mating member slidingly contacting the surface layer surface. . In addition, when the counterpart member is a blade member, the electrophotographic member has good slipperiness on the surface of the surface layer, and therefore, it is easy to suppress problems that the blade member is turned over, and it is easy to form a good image. is there. Further, when the contact area between the surface layer surface and the mating member increases, the contact area between the surface layer surface and the dirt component also increases. However, the electrophotographic member satisfies the above (4), and even if dirt components such as toner and carrier adhere to the surface of the surface layer, the stain components are easily separated from the surface of the surface layer. Therefore, in the electrophotographic member, even when the contact area between the surface of the surface layer and the dirt component increases, the dirt component hardly adheres to the surface of the surface layer, and filming can be effectively suppressed.

  In addition, each structure mentioned above can be arbitrarily combined as needed, in order to acquire each effect etc. which were mentioned above.

  The electrophotographic member according to the example will be specifically described with reference to the drawings.

Example 1
A schematic configuration of the electrophotographic member according to Example 1 will be described with reference to FIGS. 2 and 3. As shown in FIGS. 2 and 3, the electrophotographic member R is used in an electrophotographic apparatus. Specifically, the electrophotographic member of this example is a roll-like conductive member incorporated in an electrophotographic image forming apparatus, and can be used as a developing roll as a developing member or a charging roll as a charging member. it can.

  The electrophotographic member R has a surface layer 1. The surface layer 1 includes the member surface of the electrophotographic member R. That is, the surface of the surface layer 1 coincides with the member surface. Specifically, the electrophotographic member R of this example includes a shaft body 2 made of a core metal, and an elastic layer 3 made of a conductive rubber elastic body formed along the outer peripheral surface of the shaft body 2. In addition. However, both end portions of the shaft body 2 are projected from both end surfaces of the elastic layer 3. The electrophotographic member R has a surface layer 1 formed along the outer peripheral surface of the elastic layer 3.

  When the electrophotographic member R is used as a developing member, for example, a blade member for charging the toner by rubbing or forming a toner having a constant thickness is used in a state where the blade member is in contact with the surface of the surface layer 1. can do. When the electrophotographic member R is used as a charging member, for example, a blade member for removing the toner remaining on the surface after the fixing step for fixing the toner image on the paper is brought into contact with the surface of the surface layer 1. Can be used.

Here, the electrophotographic member R satisfies the following (1) to (4).
(1) Surface layer 1 thickness: 12 μm or less (2) MD-1 hardness of the member surface: 50 ° or less (3) Dynamic friction coefficient of surface layer 1 surface: 1.2 or less (4) Addition to surface layer 1 surface by contact In the primary relational expression obtained from the relationship between the vertical load W and the friction force F generated between the surface of the surface layer 1 and the contact, the friction force F ₀ when the vertical load W is 0 g is 0 g or less.

  In this example, the surface layer 1 of the electrophotographic member R contains a surface modifier made of a copolymer containing F element and Si element in the molecule. The F element is derived from a fluorine-containing group included in the copolymer, and the Si element is derived from a silicone group included in the copolymer.

  Hereinafter, a conductive roll sample as an electrophotographic member was prepared and evaluated. An experimental example will be described.

(Experimental example)
<Preparation of surface modifier>
・ Surface modifier A
In a 100 mL reaction flask, 2.0 g (0.43 mmol) of (meth) acrylate modified silicone compound (manufactured by Shin-Etsu Chemical Co., Ltd., “X-22-174DX”) and 2- (perfluorohexyl) ethyl acrylate (Daikin Industries) "R-1620" 2.0 g (4.6 mmol), 8.21 g (81.97 mmol) methyl methacrylate (manufactured by Junsei Kagaku Kogyo), 2-hydroxyethyl methacrylate (Tokyo Chemical Industry Co., Ltd.) 2.0 g (15.4 mmol), dimethyl 1,1′-azobis (1-cyclohexanecarboxylate) (Wako Pure Chemical Industries, Ltd., “VE-73”) 1.24 g (4 mmol), methyl isobutyl 12.6 g of ketone (MIBK) was charged, and after bubbling with nitrogen for 5 minutes with stirring, the temperature of the internal solution was 80 ° C. For 7 hours. Next, 23.4 g of MIBK was charged to obtain a solution containing the surface modifier A having a solid content of 30%.
The surface modifier A is made of a copolymer containing F element and Si element in the molecule. More specifically, the surface modifier A of this example is a fluorine / silicone surface modifier having a fluorine-containing group comprising an F element and a silicone group comprising an Si element at the same time.

・ Surface modifier B
In a 100 mL reaction flask, 2.0 g (0.43 mmol) of the (meth) acrylate-modified silicone compound, 8.43 g (84.17 mmol) of the methyl methacrylate, and 2.0 g of the 2-hydroxyethyl methacrylate (15 4 mmol), 1.24 g (4 mmol) of dimethyl 1,1′-azobis (1-cyclohexanecarboxylate) and 11.2 g of MIBK, and bubbling with nitrogen for 5 minutes while stirring, For 7 hours at a temperature of 80 ° C. Next, 20.7 g of MIBK was charged to obtain a solution containing the surface modifier B having a solid content of 30%.
The surface modifier B is made of a copolymer containing Si element in the molecule. More specifically, the surface modifier B of this example is a silicone-based surface modifier having a silicone group containing Si element.

・ Surface modifier C
In a 100 mL reaction flask, 2.0 g (4.6 mmol) of the 2- (perfluorohexyl) ethyl acrylate, 8.01 g (80.0 mmol) of the methyl methacrylate, and 2.0 g of the 2-hydroxyethyl methacrylate. (15.4 mmol), 1.24 g (4 mmol) of dimethyl 1,1′-azobis (1-cyclohexanecarboxylate) and 10.8 g of MIBK, and bubbling with nitrogen for 5 minutes with stirring, Polymerization was carried out at a temperature of the internal solution of 80 ° C. for 7 hours. Next, 20.1 g of MIBK was charged, and a solution containing 30% surface modifier C in solid content was obtained.
The surface modifier C is made of a copolymer containing F element in the molecule. More specifically, the surface modifying agent C of this example is a fluorine-based surface modifying agent having a fluorine-containing group containing the F element.

The amounts of the respective polymerization components charged in the synthesis of the respective surface modifiers are collectively shown in Table 1 below.

<Preparation of surface layer forming material>
As shown in Table 2, 10 parts by mass of thermoplastic polyurethane (“Nippolan 5199” manufactured by Nippon Polyurethane Industry Co., Ltd.) and polyether diol (trifunctional polypropylene glycol) (“ADEKA Polyether P-1000” manufactured by ADEKA) 60 parts by mass, 30 parts by mass of polyisocyanate (HDI-type block isocyanurate) (manufactured by Nippon Polyurethane Industry Co., Ltd., “Coronate L”), and 3 parts by mass of an electronic conductive agent (carbon black) (manufactured by Lion, “Ketjen EC300J”) Parts and each surface modifying agent of a predetermined type and a predetermined blending amount shown in Table 2 were dissolved in MEK so as to have a concentration of 20% by mass, and sufficiently mixed and dispersed using a three roll. . Thereby, each surface layer forming material used for preparation of the conductive roll samples 1-11 was prepared.

  100 parts by mass of conductive silicone rubber (Momentive Performance Materials Japan, "XE23-A2635") and 2 parts of vulcanizing agent (Momentive Performance Materials Japan, "TC-8") The elastic layer forming material A was prepared by kneading the part with a biaxial roll. Similarly, 100 parts by mass of conductive silicone rubber (Momentive Performance Materials Japan, “XE23-A2637”) and vulcanizing agent (Momentive Performance Materials Japan, “TC-8”) The elastic layer forming material B was prepared by kneading 2.5 parts by mass with a biaxial roll.

  A solid cylindrical iron bar with a diameter of 6 mm was prepared as a shaft, and an adhesive was applied to the outer peripheral surface. After setting this shaft body in the hollow space of the roll molding die, the predetermined elastic layer forming material shown in Table 2 was injected into the hollow space, heated at 170 ° C. for 30 minutes to be cured, and demolded. . Thereafter, preheating was performed at 200 ° C. for 2 hours. Thereby, a roll-shaped elastic layer (thickness 3 mm) made of a predetermined conductive silicone rubber was formed along the outer peripheral surface of the shaft body.

  Next, each of the prepared surface layer forming materials was applied to the outer peripheral surface of the elastic layer by a roll coating method, and then heated and cured at 120 ° C. for 60 minutes to form a surface layer. Thereby, the conductive roll samples 1-11 of the two-layer structure which have a surface layer along the outer peripheral surface of the said elastic layer were produced. The surface layer contains each surface modifier shown in Table 2 as an additive in a mixed polymer of thermoplastic polyurethane and thermosetting polyurethane that forms the skeleton of the surface layer.

<Measurement of various physical properties>
(1) Surface layer thickness Each surface layer cross section was observed using a scanning electron microscope, and the average value of the measured surface layer thickness values was obtained to obtain the surface layer thickness. Specifically, the measurement position was set to a position of 20 mm from the central portion of the surface layer in the roll axis direction and from the both end surfaces of the surface layer to the central portion side.

(2) Member surface hardness A surface layer surface that is a sample surface using a spring type hardness tester (manufactured by Kobunshi Keiki Co., Ltd., micro rubber hardness tester, MD-1 type) adopting a cantilever leaf spring type load system. Then, the tip of the push needle of the test machine was brought into contact with it and pressurized vertically with a load of 33.85 g, and the scale was immediately read. Specifically, the measurement position is a position of 20 mm from the center part of the surface layer in the roll axis direction and from the both end surfaces of the surface layer toward the center part side. The average value of the values obtained for each sample was defined as the member surface hardness of the sample.

(3) Dynamic friction coefficient μk of surface layer surface
Using a static / dynamic friction coefficient measuring device (“Tribostar 500” manufactured by Kyowa Interface Science Co., Ltd.), 50 g of vertical load W was applied to the surface of the surface layer with a contact made of a steel ball having a diameter of 3 mm. In this state, the surface layer was moved 1 cm in the horizontal direction at a moving speed of 7.5 mm / sec. Thus, the F / W value (initial value) was calculated as the dynamic friction coefficient μk of the surface layer surface from the frictional force F generated between the surface layer surface and the contact.

(4) Friction force F ₀
Using the static / dynamic friction coefficient measuring instrument, 10 g of vertical load W was applied to the surface of the surface layer with a contact made of a steel ball having a diameter of 3 mm. In this state, the surface layer was moved 1 cm in the horizontal direction at a moving speed of 7.5 mm / sec. Thus, to measure the frictional force F ₁₀ generated between the surface layer surface and contacts. Similarly, changing the vertical load W to 50 g, to measure the frictional force _{F 50.} Then, a straight line passing through two points of coordinates (vertical load W [g], friction force F [g]) = (10, F ₁₀ ) and (50, F ₅₀ ) is obtained, and the vertical load W in the straight line is 0 g. frictional force when, that is, determine the value of the intercept in the linear, to calculate a frictional force F _0.

<Toner degradation resistance evaluation>
Each of the conductive roll samples was used as a developing roll, and the toner deterioration resistance was evaluated. Specifically, each conductive roll sample is incorporated in a toner cut ridge of a commercially available color printer (“Color Laser Jet Pro 400 Color M451dn” manufactured by Hewlett-Packard Japan) that is not used as a developing roll. 5000 halfton images with 5% printing were output in an environment of 10% RH. Thereafter, an unused developing roll having the same specifications was re-installed in the toner cartridge, and a solid image was output under an environment of 32.5 ° C. × 80% RH. At the initial stage of output, the toner (styrene-acrylic toner) on the surface of the developing roll is sucked and collected using a metal cylindrical tube and a cylindrical filter. At this time, the amount of charge stored in the capacitor through the metal cylindrical tube The absolute value Q (μC) of the toner and the total mass M (g) of the collected toner were measured. Then, the toner charge amount Q / M (μC / g) per unit mass was calculated.
When the toner charge amount Q / M was 15 (μC / g) or more, it was determined as “pass” as the toner deterioration was suppressed. When the toner charge amount Q / M was less than 15 (μC / g), it was determined as “Fail” because the deterioration of the toner was not suppressed.

<Filming resistance evaluation>
Each said conductive roll sample was used as a developing roll, and filming resistance was evaluated. Specifically, each conductive roll sample is incorporated in a toner cut ridge of a commercially available color printer (“Color Laser Jet Pro 400 Color M451dn” manufactured by Hewlett-Packard Japan) that is not used as a developing roll. 5000 halfton images with 5% printing were output in an environment of 10% RH. Thereafter, the toner in the toner cartridge was removed, and unused toner was filled, and a solid image was output in an environment of 32.5 ° C. × 80% RH. At the initial stage of output, the toner (styrene-acrylic toner) on the surface of the developing roll is sucked and collected using a metal cylindrical tube and a cylindrical filter. At this time, the amount of charge stored in the capacitor through the metal cylindrical tube The absolute value Q (μC) of the toner and the total mass M (g) of the collected toner were measured. Then, the toner charge amount Q / M (μC / g) per unit mass was calculated.
When the toner charge amount Q / M was 15 (μC / g) or more, the filming was suppressed, and the result was “pass”. When the toner charge amount Q / M was less than 15 (μC / g), the filming was not suppressed, and the result was “failed”.

  The detailed configuration and evaluation results of each conductive roll sample are shown in Table 2 below.

  As shown in Table 2, any of the conductive rolls of Samples 2 to 11 is not within a predetermined range among the various physical properties of (1) to (4). Therefore, it can be seen that it is difficult for each of these conductive rolls to achieve both suppression of toner deterioration and suppression of filming.

On the other hand, as for the electroconductive roll of the sample 1, various physical properties of (1)-(4) are made into the predetermined range. Therefore, it was confirmed that the conductive roll of Sample 1 sufficiently suppresses toner deterioration and filming, and can suppress both toner deterioration and filming. Regarding the physical properties of (4), the reason why the frictional force F ₀ is 0 g or less is not clear. However, from the above results, it can be said that the lower the value of the frictional force F ₀ , the more easily dirt components such as toner and carrier are separated from the surface of the surface layer, and it is easier to suppress filming.

  As mentioned above, although the Example of this invention was described in detail, this invention is not limited to the said Example, A various change is possible within the range which does not impair the meaning of this invention.

  For example, in the above experimental example, the conductive roll is applied as the developing roll, but it can also be applied as a charging roll. This is because, like the developing roll, the charging roll is used in the presence of toner, and both suppression of toner deterioration and suppression of filming are required.

R Electrophotographic member 1 Surface layer

Claims (4)

An electrophotographic member having a surface layer and used in an electrophotographic apparatus,
An electrophotographic member characterized by satisfying the following (1) to (4).
(1) Thickness of the surface layer: 12 μm or less (2) MD-1 hardness of the member surface: 50 ° or less (3) Dynamic friction coefficient of the surface layer surface: 1.2 or less (4) Addition to the surface layer by a contactor In the primary relational expression obtained from the relationship between the vertical load W and the friction force F generated between the surface of the surface layer and the contact, the friction force F ₀ when the vertical load W is 0 g is 0 g or less.   The electrophotographic member according to claim 1, further comprising an elastic layer in contact with an inner surface of the surface layer.   The electrophotographic member according to claim 1, wherein the member has a roll shape.   The electrophotographic member according to claim 1, wherein the electrophotographic member is a developing member or a charging member incorporated in an electrophotographic image forming apparatus.

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