JP5662825B2 - Developing roll for electrophotographic equipment - Google Patents

Description

  The present invention relates to a developing roll for an electrophotographic apparatus that is preferably used in an electrophotographic apparatus such as a copying machine, a printer, or a facsimile that employs an electrophotographic system.

  2. Description of the Related Art Conventionally, electrophotographic apparatuses such as copying machines, printers, and facsimile machines that employ an electrophotographic system are known. Generally, a photosensitive drum is incorporated in the electrophotographic apparatus, and conductive rolls such as a developing roll, a charging roll, a transfer roll, and a toner supply roll are disposed around the photosensitive drum.

  There are various types of developing rolls for this type of electrophotographic apparatus. For example, a shaft body, a rubber elastic layer formed on the outer periphery of the shaft body, and a coating layer formed on the outer periphery of the rubber elastic layer The thing equipped with these is known. At this time, a concavo-convex shape may be formed on the surface of the developing roll for the purpose of, for example, enhancing toner transportability and chargeability.

  For example, in Patent Document 1, a roll in which a coating material in which resin particles such as urethane resin are dispersed is applied to the surface of the rubber elastic layer, and a coating layer in which the resin particles are dispersed is formed on the surface of the rubber elastic layer. It has been shown that an uneven shape is formed on the surface.

  Further, in Patent Document 2, when electroless plating is performed on the inner surface of a mold for forming a rubber elastic layer, hydrogen gas generated during the plating reaction is easily adsorbed to the plating surface, By inhibiting the deposition of plating, a recess due to plating defects is formed on the inner surface of the molding die, and this is transferred to the surface of the rubber elastic layer to form an uneven shape on the roll surface. Has been.

JP 2001-132732 A JP 2006-184608 A

  However, in the configuration described in Patent Document 1, since the resin particles are dispersed in the coating layer, the portion (convex portion) where the resin particles are present on the roll surface is harder than the other portions. Further, the convex portion on the roll surface is a portion that is particularly in contact with the layer forming blade when the toner is conveyed, and the layer forming blade is susceptible to stress at the portion that contacts the convex portion. For this reason, the toner particles are liable to be crushed between the layer forming blade and the convex portion of the roll surface, and the problem that the toner adheres to the surface of the layer forming blade or the like during repeated use of the developing roll tends to occur.

  Further, in the configuration described in Patent Document 2, the size of the recesses on the inner surface of the molding die cannot be controlled because the portion subjected to reaction is large. The size of the recess formed on the inner surface of the molding die is too larger than the average particle diameter of the toner particles. Further, the recesses are sparsely formed on the inner surface of the molding die, and the proportion of the recesses in the inner surface of the molding die is small. Furthermore, the space | interval of a recessed part and a recessed part is too wide, and there are too many smooth parts on the inner surface of a shaping | molding die.

  For this reason, in the developing roll described in Patent Document 2, the layer forming blade is likely to be in surface contact with the convex portion or the flat portion on the surface of the developing roll. As a result, stress concentrates on the portion of the layer forming blade in contact with the roll surface, so that the toner particles are easily crushed between the layer forming blade and the roll surface. There was a tendency for the toner to stick to the toner.

  In order to provide a high-quality image, it is advantageous that the image is fine. However, in the conventional developing roll, no measures have been taken to increase the fineness of the image.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developing roll for an electrophotographic apparatus that can suppress the adhesion of toner particles to a layer forming blade for a long period of time and can fine-tune an image.

In order to solve the above problems, a developing roll for electrophotographic equipment according to the present invention is a developing roll for electrophotographic equipment comprising a shaft and a rubber elastic layer formed on the outer periphery of the shaft. On the surface of the rubber elastic layer, a large number of convex portions having a ratio of the height h to the diameter φ ₁ (h / φ ₁ ) of 0.5 or more are formed by mold transfer, and the large number of convex portions are formed. Further, the surface of the rubber elastic layer is further subjected to surface modification that enhances toner releasability, and any one of the following a to d is used for the surface modification. To do.
(A) Surface treatment A in which the following a1 component and a2 component are brought into contact with the surface of the rubber elastic layer
(A1) Trichloroisocyanuric acid (a2) Compound having an unsaturated carbon-carbon double bond and a functional group for imparting a function to the surface of the rubber elastic layer (b) On the surface of the rubber elastic layer, Surface treatment B in which the following b1 component and b2 component are contacted
(B1) a compound having two or more thiol groups (b2) a compound having a functional group capable of reacting with a thiol group and a functional group for imparting a function to the surface of the rubber elastic layer (c) the rubber elasticity Surface treatment C in which the following c1 component and c2 component are brought into contact with the surface of the layer
(C1) X ¹ (OX ² ) _n (where X ¹ is a hydrogen atom, alkali metal element, alkaline earth metal element or alkyl group, X ² is a halogen atom, and n is the same as the valence of X ¹⁾ And a compound having a —CONX ² — bond in the molecule (where X ² is a halogen atom), or two or more types (c2) BF ₃
(D) Surface treatment D with ultraviolet rays

According to the developing roll for an electrophotographic apparatus of the present invention, the ratio of the height h to the diameter φ ₁ (h / φ ₁ ) is 0 by the mold transfer on the surface of the rubber elastic layer formed on the outer periphery of the shaft body. A large number of convex portions of 5 or more are formed. As described above, by increasing the height of the convex portion, even when the layer forming blade is pressed, the clearance is held in the concave portion between the convex portion and the convex portion. As a result, the contact of the toner particles with the surface of the roll is reduced, so that the adhesion of the toner particles to the surface of the layer forming blade is suppressed for a long time.

Furthermore, the surface of the rubber elastic layer on which a large number of protrusions are formed is surface-modified without forming a coating layer, so that the fine uneven shape formed on the surface of the rubber elastic layer remains as it is. Is maintained at. According to the mold transfer, a convex portion having a height lower than this is present on the roll surface in addition to the convex portion having a ratio of the height h to the diameter φ ₁ (h / φ ₁ ) of 0.5 or more. . Since the minute convex portions remain on the roll surface without disappearing, it is possible to suppress the occurrence of a portion where the convex portions are sparse on the roll surface. That is, since the variation in the density of the convex portions is less likely to occur on the roll surface, the variation in the density of the obtained image can be suppressed. Thereby, a fine image can be obtained.

1A is a schematic view of a developing roll for an electrophotographic apparatus according to an embodiment of the present invention, and FIG. It is a partially expanded view (enlarged view of B part) of the roll surface of FIG.1 (b). It is a schematic diagram which shows a mode when the layer formation blade is pressed on the surface of the rubber elastic layer. It is a schematic diagram explaining the state when the picked-up image of the rubber elastic layer surface is binarized using the discriminant analysis method. It is a circumferential direction sectional view of an example of a mold suitable for mold fabrication of a rubber elastic layer. It is a figure which shows an example of the manufacturing process of the shaping | molding die shown in FIG. It is a figure which shows an example of the manufacturing process of the shaping | molding die shown in FIG. 2 is a circumferential cross-sectional photograph of a molding die of Example 1. FIG.

  Next, the developing roll for electrophotographic equipment of the present invention (hereinafter sometimes referred to as a developing roll) will be described in detail with reference to the drawings.

  FIG. 1A is a schematic view of a developing roll according to an embodiment, and FIG. 1B is an AA cross-sectional view (circumferential cross-sectional view) of the developing roll shown in FIG. . 2 (a) and 2 (b) are partially enlarged views of part B of the roll surface of the developing roll shown in FIG. 1 (b). FIG. 3 is a schematic view showing a state when the layer forming blade is pressed against the surface of the rubber elastic layer. FIG. 4 is a schematic diagram for explaining a state when a captured image on the surface of the rubber elastic layer is binarized using a discriminant analysis method.

  As shown in FIG. 1, the developing roll 10 includes a shaft body 12 and a rubber elastic layer 14 formed on the outer periphery of the shaft body 12. In the developing roll 10, the rubber elastic layer 14 is the outermost layer of the developing roll 10, and the rubber elastic layer 14 is a layer constituting the surface of the developing roll 10. Therefore, no coating layer is formed on the outer periphery of the rubber elastic layer 14.

  As shown in FIGS. 2A and 2B, a plurality of convex portions 16 are formed on the surface of the rubber elastic layer 14, and the rubber elastic layer 14 has an uneven shape on the surface. As a result, toner transportability and chargeability are improved. The plurality of convex portions 16 are formed by mold transfer.

When the diameter of the convex portion 16 is φ ₁ and the height of the convex portion 16 is h, some of the convex portions 16 (16 a) of the plurality of convex portions 16 are higher than the diameter φ ₁ . The ratio h (h / φ ₁ ) is set to be 0.5 or more. Since the plurality of convex portions 16 are formed by mold transfer, the ratio of the height h to the diameter φ ₁ (h / φ ₁ ) is 0.5 or more on the surface of the rubber elastic layer 14. In addition to the convex portion 16 (16a), there is a convex portion 16 (16b) having a lower height.

In FIG. 2A, the ratio of the height h to the diameter φ ₁ (h / φ ₁ ) is 0.5 or more and less than 1.0, and the h / φ ₁ is 0.5. An example of the surface structure which has the convex part 16 (16b) used as less than is shown. On the other hand, in FIG. 2B, the convex portion 16 (16a) having a ratio of 0.5 or more, including the ratio of the height h to the diameter φ ₁ (h / φ ₁ ) of 1.0 or more, h / phi ₁ shows an example of a surface structure having a convex portion 16 (16b) which is less than 0.5.

  In the developing roll 10, by setting the height of some of the plurality of convex portions 16 to be relatively high, a layer forming blade 32 is formed on the surface of the rubber elastic layer 14 as shown in FIG. Even if is pressed, the clearance is held in the concave portion between the convex portion 16 and the convex portion 16. As a result, contact by the surface of the toner particles 30 with respect to the roll surface is reduced (contact by points is likely to occur), and thus the adhesion of the toner particles 30 to the surface of the layer forming blade 32 is suppressed for a long time. The

Among the plurality of protrusions 16, the proportion h / phi ₁ ratio of 0.5 or more posts 16 (16a) is not particularly limited, the fixation of the toner particles to the layer formation blade surface From the viewpoint of easy suppression, it is preferably 50% or more. More preferably, it is 70% or more. On the other hand, the upper limit of the ratio h / phi ₁ ratio occupied by 0.5 or more posts 16 (16a) is not particularly limited.

The plurality of convex portions 16 may have the same diameter φ ₁ , may have different sizes, or may have a diameter φ ₁ at some of the convex portions 16. May be the same size. Further, the plurality of convex portions 16 may have the same height h, may be different from each other, or may have the same height h among some of the convex portions 16.

For the h / phi ₁ ratio of 0.5 or more posts 16 (16a), and more preferably h / phi ₁ ratio of 0.8 or more, more preferably h / phi ₁ ratio is 1.0 or more And good. When the h / φ ₁ ratio has a convex portion 16 (16a) having a ratio of 1.0 or more, when the layer forming blade is pressed against the surface of the rubber elastic layer 14, the gap between the convex portion 16 and the convex portion 16 is increased. The effect of ensuring the clearance in the recess is particularly high.

About the convex part 16 formed in the surface of the rubber elastic layer 14, it is preferable that it is 2 or less as an upper limit of said h / (phi) ₁ ratio. If h / phi ₁ ratio of the convex portion 16 is more than 2, due to the method of forming the convex portion 16, the diameter at the proximal end of the protrusion 16 becomes too smaller than the diameter of intermediate portion The convex portion 16 tends to be a so-called spindle shape. Therefore, the strength of the convex portion 16 tends to decrease. Alternatively, it may be difficult to form the convex portion 16 due to the method of forming the convex portion 16. For the same reason, the upper limit value of the h / phi ₁ ratio, more preferably 1.8 or less, more preferably 1.7 or less.

As a magnitude | size of diameter (phi) ₁ of the convex part 16, the inside of the range of 1-15 micrometers is preferable. Since the average particle diameter of the toner particles is usually in the range of 5 to 12 μm, when the diameter φ ₁ of the convex portion 16 is in this range, the diameter φ ₁ of the convex portion 16 is the toner particle. The size is equal to or less than. Therefore, the contact by the surface between one convex part 16 and a toner particle is reduced. When the size of the diameter φ ₁ of the convex portion 16 exceeds 15 μm, surface contact is likely to occur between one convex portion 16 and the toner particles. Therefore, the toner particles are likely to be fixed to the surface of the layer forming blade. On the other hand, when the diameter φ ₁ of the convex portion 16 is less than 1 μm, the clearance of the concave portion between the convex portion 16 and the convex portion 16 may be difficult to be maintained when the layer forming blade is pressed. The size of the diameter φ ₁ of the convex portion 16 is more preferably in the range of 2 to 10 μm, and still more preferably in the range of 5 to 10 μm.

  As height h of the convex part 16, the inside of the range of 1-30 micrometers is preferable. More preferably, it exists in the range of 2-25 micrometers, More preferably, it exists in the range of 4-20 micrometers. By setting the convex portion 16 higher, it is possible to improve toner transportability and chargeability. In addition, when the layer forming blade is pressed against the surface of the rubber elastic layer 14, the effect of ensuring the clearance in the concave portion between the convex portion 16 can be enhanced.

On the surface of the rubber elastic layer 14, the area ratio Ap ₁ of the protrusions 16 is preferably in the range of 42 to 78.5%. More preferably, it is in the range of 45-60%. If Ap ₁ is within a specific range, the width of the concave portion between the convex portions 16 can be configured to be equal to or smaller than the average particle diameter of the toner particles. Since the distance between the protrusions 16 is sufficiently narrow compared to the average particle diameter of the toner particles, the toner particles are reliably point-contacted with the plurality of protrusions 16. Thereby, since the load on the toner particles is reduced, the adhesion of the toner particles to the surface of the layer forming blade is surely suppressed. The area ratio Ap ₁ of the convex portion 16, h / phi ₁ ratio means the area ratio of all of the projections 16 with 0.5 or more protrusions 16 (16a).

When Ap ₁ exceeds 78.5%, the space between the convex portions 16 becomes narrower than the average particle diameter of the toner particles, and when the layer forming blade is pressed, the convex portions The clearance of the recessed part between 16 and the convex part 16 may be difficult to be maintained. Therefore, contact with the surface of the toner particles tends to occur. On the other hand, when Ap ₁ is less than 42%, the space between the convex portions 16 is widened, and the contact between the convex portions 16 and the convex portions 16 is likely to occur due to the surface of the toner particles.

Here, the area ratio Ap ₁ of the convex part 16 is an area ratio of the convex part 16 when the surface of the rubber elastic layer 14 is observed. Specifically, it is the area ratio of the convex portion 16 when the captured image of the surface of the rubber elastic layer 14 is binarized using a discriminant analysis method. The photographed image is obtained by photographing an area of 0.4 × 0.4 mm or more on the surface of the rubber elastic layer 14 with a resolution of at least 1000 × 1000 dpi. At this time, the size of one dot is set to be 1/15 or less of the diameter of the convex portion 16 on the image.

In order to calculate the Ap ₁ , specifically, the surface of the rubber elastic layer 14 is enlarged with a lens, and an area of 0.5 × 0.4 mm is captured with a resolution of 1280 × 1024 dpi, which is used as an evaluation target. . Next, in order to make it easy to binarize the image, the obtained image is converted to monochrome, and noise is removed with a smoothing filter to smooth the uneven illuminance on the image, and then binarized using a discriminant analysis method To do. FIG. 4 shows a schematic diagram of an example of a binarized image.

  Next, in order to calculate the area of the convex portion 16 and to make it easier to remove noise, the binarized image is subjected to black-and-white reversal processing to fill in noise generated inside the white portion that is the convex portion 16. After removal, the area of the white part is measured. The area can be measured using commonly used image processing software.

  A general microscope can be used for such a series of image processing, but it is particularly preferable to use a microscope Mx-1200E manufactured by Nakaden. In a general microscope, for example, the focusing operation is performed on a portion where the convex portion 16 on the surface of the rubber elastic layer 14 does not exist. However, since the microscope Mx-1200E can easily capture a three-dimensional depth composite image, The surface of the rugged rubber elastic layer 14 can be observed more clearly. The binarization process can be performed using, for example, NanoHunter NS2K-Pro / Lt manufactured by Nanosystem Corporation.

The diameter φ ₁ and the height h of the convex portion 16 of the rubber elastic layer 14 are determined by a laser microscope (for example, VK-9510, manufactured by Keyence Corporation) or a microscope (for example, Nakaden) that can observe the circumferential cross section of the developing roll 10. Manufactured by Mx-1200E).

  The rubber elastic layer 14 can be formed by molding using a molding die. More specifically, a cylindrical molding die as shown in FIG. 5 is used, the shaft body 12 is set in the hollow portion of the molding die, and a rubber material is poured into the gap between the molding die and the shaft body 12. The rubber elastic layer 14 can be formed on the outer periphery of the shaft body 12 by removing the mold from the mold after the mold is heated and crosslinked.

  In this case, a molding die 20 having a plurality of concave portions for forming the plurality of convex portions 16 of the rubber elastic layer 14 on the inner surface (transfer surface) of the molding die is used as the molding die. 16 can be formed. In addition, after the rubber elastic layer 14 having no plurality of convex portions 16 is molded, a rubber mold having no plurality of convex portions 16 is formed by using a molding die 20 having a plurality of concave portions on the inner surface (transfer surface) of the molding die. A plurality of convex portions 16 may be transferred onto the surface of the layer 14.

  The rubber elastic layer 14 can also be formed by a known method other than molding. Examples of methods other than mold forming include methods such as extrusion. In the extrusion molding, the rubber elastic layer 14 may be formed directly on the outer periphery of the shaft body 12 or through an adhesive layer such as an adhesive, or a tube body for forming the rubber elastic layer 14 is separately formed into a tube shape. It may be molded. In the case of forming the rubber elastic layer 14 or the tube body for forming the rubber elastic layer 14 by extrusion molding, the convex portions 16 on the surface cannot be formed simultaneously with the extrusion molding. Using the molding die 20 on the inner surface (transfer surface) of the molding die, the plurality of protrusions 16 can be transferred onto the surface of the rubber elastic layer 14 not having the plurality of protrusions 16.

As a configuration of a molding die that can be suitably used when the plurality of convex portions 16 are transferred onto the surface of the rubber elastic layer 14, a molding die 20 shown in FIG. The mold 20 includes a cylindrical mold base 22 and a plating film 24 formed on the inner peripheral surface of the mold base 22. On the surface of the plating film 24, a large number of recesses having a ratio of the depth d ₂ to the diameter φ ₂ (d ₂ / φ ₂ ) of 0.5 or more are formed. Since many concave portions having a high aspect ratio are formed on the inner peripheral surface of the mold 20, the convex portions 16 corresponding to the concave portions are transferred and formed on the outer peripheral surface of the rubber elastic layer 14. Thereby, a large number of convex portions 16 having a high aspect ratio are formed on the surface of the rubber elastic layer 14.

  As an example of a method for manufacturing such a mold 20, an electroless plating process for forming an electroless plating layer on the inner peripheral surface of a cylindrical mold base 22, and a surface of the formed electroless plating layer And a recess forming step of forming a large number of recesses.

  6 and 7 are process diagrams illustrating an example of a method for manufacturing the mold 20. 6 and 7 are enlarged views of the portion C shown in FIG.

  In the electroless plating step, first, a plating solution containing the resin particles 26 is prepared. Next, electroless plating is performed on the inner peripheral surface of the mold base 22 using the prepared plating solution. During the electroless plating, the resin particles 26 co-deposit with the plating metal. Thereby, the resin particles 26 are contained in the electroless plating layer 28.

  In the example shown in FIG. 6, as shown in FIG. 6A, the plated metal is crystal-grown to a height lower than the vertex of the resin particle 26 so that the vertex of the resin particle is exposed. On the other hand, in the example shown in FIG. 7, as shown in FIGS. 7A to 7B, the thickness of the electroless plating layer 28 is increased to a height higher than the apex of the resin particles 26 contained in the electroless plating layer 28. The plated metal is crystal-grown along the vertical direction (upward in FIG. 7B).

  In order to grow a plated metal crystal as shown in FIGS. 7A to 7B, for example, an amine compound may be used as a complexing agent for the plating solution. According to this, the plating metal can be crystal-grown in a columnar shape. Therefore, for example, by using an amine compound as a complexing agent for the plating solution, the plating metal can be crystal-grown along the thickness direction of the electroless plating layer 28.

  When the plated metal crystal grows in a columnar shape, even if the plating is performed to a height higher than the apex of the resin particles 26, the crystal growth is difficult in the direction perpendicular to the thickness direction of the electroless plating layer 28, and the resin particles 26 are not formed. It is difficult to be buried in the electrolytic plating layer 28. In the electroless plating layer 28, a communication hole 28 a that communicates from the surface of the resin particle 26 to the outside of the electroless plating layer 28 along the thickness direction of the electroless plating layer 28 is formed above the resin particle 26. The

  On the other hand, as shown in FIG. 6 (a), when the plating metal is grown to a height lower than the apex of the resin particles 26, an amine compound may be used as a complexing agent for the plating solution. It is not necessary. When an amine compound is not used as the complexing agent for the plating solution, the plating metal grows mainly along the direction orthogonal to the thickness direction of the electroless plating layer 28 (the plating metal grows in layers). Therefore, if the plating metal is crystal-grown higher than the apex of the resin particles 26, the resin particles may be covered with the plating metal, and the resin particles 26 may be embedded in the electroless plating layer 28.

  In the recess forming step, the resin particles 26 in the electroless plating layer 28 are dissolved and removed using a solvent in which the resin particles 26 are soluble. More specifically, for example, it is performed by immersing the mold base 22 on which the electroless plating layer 28 is formed in a solvent in which the resin particles 26 are soluble. By dissolving and removing the resin particles 26 with this solvent, the recesses 24a are formed in the portions where the resin particles 26 existed.

In the example shown in FIG. 6, since the plating metal is grown to a height lower than the apex of the resin particles 26, the depth of the recess 24 a is set to the depth of the resin particles 26 as shown in FIG. Although it is smaller than the average particle size, it is possible to make it larger than the radius of the resin particles 26 (1/2 the average particle size). Therefore, a large number of recesses 24 a having a ratio of the depth d ₂ to the diameter φ ₂ (d ₂ / φ ₂ ) of 0.5 or more can be formed on the surface of the obtained plating film 24. In the example shown in FIG. 6, for example, the surface structure shown in FIG. 2A can be obtained.

On the other hand, in the example shown in FIG. 7, the plated metal is crystal-grown to a height higher than the apex of the resin particles 26, but the resin particles 26 contained in the electroless plating layer 28 are dissolved and removed by the communication holes 28 a. It is possible. In the example shown in FIG. 7, the plating metal is crystal-grown up to a height equal to or higher than the apex of the resin particles 26, and therefore the depth of the recess 24 a is set to the resin particle 26 as shown in FIG. 7C. It is possible to make it larger than the average particle diameter. Therefore, a large number of recesses 24a having a ratio of the depth d ₂ to the diameter φ ₂ (d ₂ / φ ₂ ) of 1.0 or more can be formed on the surface of the obtained plating film 24. That is, in this case, a recess having a high aspect ratio can be formed. In the example shown in FIG. 7, for example, the surface structure shown in FIG. 2B can be obtained.

  Examples of the solvent in which the resin particles 26 are soluble include acetone, MEK, toluene, THF, DMF, and NMP. The solvent may be appropriately selected and used depending on the type of the resin particles 26. Two or more solvents may be mixed and used.

  The plating solution contains metal ions, a reducing agent, a complexing agent, a pH buffer, the resin particles 26, and the like. The metal ions are plating metal ions. Examples of the plating metal include nickel, cobalt, copper, gold, and silver. Among these, nickel is preferable from the viewpoint of corrosion resistance and cost. Examples of the reducing agent include hypophosphorous acid, dimethylamine borane, hydrazine and the like. Of these, hypophosphorous acid is preferred from the viewpoint of the stability of the plating solution. Examples of pH buffering agents include lactic acid, acetic acid, and succinic acid.

  Examples of complexing agents include carboxylic acids and amine compounds. As a complexing agent, only carboxylic acid may be used, only an amine compound may be used, or carboxylic acid and an amine compound may be used in combination. When the carboxylic acid and the amine compound are used in combination, the resin particles 26 can be co-deposited with the plating metal at a high density. When an amine compound is used, as described above, the plated metal can be crystal-grown in a columnar shape.

  Specific examples of the amine compound include glycine, alanine, ethylenediamine, and propanediamine. Among these, glycine is preferable from the viewpoint of high dispersion stability of the resin particles 26. Examples of the carboxylic acid include citric acid, malic acid, tartaric acid and the like. Among these, citric acid is preferable from the viewpoint of easily allowing the resin particles 26 to eutect with high density. As the complexing agent, it is particularly preferable to use glycine and citric acid in combination.

  When an amine compound is used as the complexing agent for the plating solution, the amine compound may be used from the beginning of the electroless plating step, or the amine compound may be used from the middle of the electroless plating step. In the former case, for example, using the same plating solution containing an amine compound, the plating can be performed up to the height of the top of the resin particles 26 in one step. On the other hand, in the latter case, the plating solution is changed to a plating solution containing an amine compound during the electroless plating step. Specifically, for example, plating is performed using a plating solution that does not contain an amine compound up to a height that does not exceed the apex of the resin particles 26 (for example, up to half of the height direction of the resin particles 26). The plating solution is changed to a plating solution containing, and plating is performed up to the height of the resin particle 26 or higher. Thereby, the plating metal can be grown in a columnar shape from the middle of the electroless plating process.

  A surfactant can be further blended in the plating solution. Examples of the surfactant include a cationic surfactant and an amphoteric surfactant. Among these, it is preferable to mix a cationic surfactant from the viewpoint of increasing the degree of dispersion of the resin particles 26. In addition, the amount of eutectoid deposited on the electroless plating layer 28 of the resin particles 26 can be increased by adding the resin particles 26 to the plating solution after the resin particles 26 are positively charged.

  Examples of the cationic surfactant include quaternary ammonium salt types such as lauryltrimethylammonium chloride and ethylene oxide addition type ammonium chloride. These may be used alone or in combination. Examples of amphoteric surfactants include betaine types such as lauryl betaine, amidopropyl betaine, and dimethylalkylbetaine. These may be used alone or in combination. The compounding amount of the cationic surfactant or the amphoteric surfactant is preferably in the range of 0.01 to 10 g / L.

  As the resin particles 26, resin particles soluble in a solvent are used. Examples of such resin particles include acrylic particles, styrene particles, urethane particles, nylon particles, silicone particles, and cellulose particles. As the resin particle 26, a single type of resin particles may be used, or a plurality of types of resin particles may be used in combination. Among these, acrylic particles and styrene particles are preferable from the viewpoints of excellent dispersibility in the plating solution and formation of a uniform uneven surface on the surface of the plating film 24.

  The average particle size of the resin particles 26 is 15 μm or less from the viewpoint that the convex portions 16 having a size equal to or smaller than the average particle size of the toner particles can be formed on the surface of the rubber elastic layer 14 during mold transfer. Is preferred. More preferably, it exists in the range of 1-15 micrometers, More preferably, it exists in the range of 2-10 micrometers. As the resin particles 26, those having different average particle diameters may be used in combination. The average particle diameter of the resin particles 26 can be measured with a Microtrac particle size distribution analyzer UPA-EX150 manufactured by Nikkiso Co., Ltd.

  The blending amount of the resin particles 26 in the plating solution is preferably in the range of 0.1 to 100 g / L when the average particle diameter of the resin particles 26 is in the range of 1 to 15 μm. More preferably, it is in the range of 3 to 20 g / L. Thereby, a concave portion (a portion between the convex portion 16 and the convex portion 16) having a size equal to or smaller than the average particle diameter of the toner particles can be formed on the surface of the rubber elastic layer 14 during the mold transfer.

By adjusting the size of an average particle diameter of the resin particles 26, it is possible to adjust the size of the diameter phi ₁ of the convex portion 16 of the diameter of the recess 24a phi ₂ and the developing roll 10 of the mold 20. Further, by adjusting the amount of the plating liquid of resin particles 26, it is possible to adjust the area ratio Ap ₁ of the convex portion 16 of the area of the recess 24a proportion Ap ₂ and the developing roll 10 of the mold 20.

  The resin particles 26 may be subjected to an etching treatment with an acid such as hydrochloric acid or sulfuric acid before being added to the plating solution for the purpose of improving wettability to the plating solution. Furthermore, the degree of dispersion of the resin particles 26 can be further increased by sonicating the plating solution to which the resin particles 26 are added.

  Here, the surface of the rubber elastic layer 14 on which a large number of convex portions 16 are formed is further subjected to surface modification that improves toner releasability. Any of the following a to d is used for the surface modification.

(A) is a surface treatment A in which the following a1 component and a2 component are brought into contact with the surface of the rubber elastic layer. The a2 component may be composed of only one kind of compound or may be composed of a mixture of two or more kinds of compounds.
(A1) Trichloroisocyanuric acid (a2) having an unsaturated carbon-carbon double bond and a functional group for imparting a function to the surface of the rubber elastic layer (hereinafter sometimes referred to as a specific functional group). Compound

  In the surface treatment A, the a1 component and the a2 component may be simultaneously contacted with the surface of the rubber elastic layer (simultaneous contact), or the a2 component may be contacted after the a1 component is contacted (step contact). . In the former case, a surface modifier containing an a1 component and an a2 component is used. In this case, the a1 component undergoes an addition reaction with the unsaturated carbon-carbon double bond of the a2 component. This reaction proceeds sufficiently at room temperature. This reaction is shown in Equation 1 below. In the latter case, the surface modifier containing the a1 component and the surface modifier containing the a2 component are used stepwise.

However, R < ¹ > is a substituent which has a specific functional group. R ^{2, R 3,} R ⁴ may be a substituent of the same structure as R ^1, it may be a substituent having a different particular functional group as R ^1, an alkyl group or hydrogen group It may be. In addition, R ¹ , R ² , R ³ , and R ⁴ may be substituents having specific functional groups different from each other, and some of R ¹ , R ² , R ³ , and R ⁴ are the same. It may be a substituent. More preferably, from the viewpoint of stability and the like, R ² , R ³ and R ⁴ are preferably hydrogen groups.

  The surface treatment A can be applied to a rubber elastic layer formed of a polymer containing an organic component having an unsaturated carbon-carbon double bond. The organic component may be a polymer component of the rubber elastic layer, or may be a low molecular weight component or an oligomer component mixed with the polymer component. That is, the polymer component itself may have an unsaturated carbon-carbon double bond, or a low molecular weight component or an oligomer component mixed with the polymer component may have an unsaturated carbon-carbon double bond. . The polymer component may be any of rubber, resin, and elastomer.

  Polymer components having unsaturated carbon-carbon double bonds include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR), chloroprene rubber ( CR), butyl rubber (IIR), ethylene propylene diene rubber (EPDM) and the like.

  In addition, even if a polymer component originally has no unsaturated carbon-carbon double bond, the unsaturated carbon-carbon double bond is formed by copolymerization with a monomer component having an unsaturated carbon-carbon double bond. It can be an introduced polymer component. Such polymer components that normally do not have unsaturated carbon-carbon double bonds include acrylic rubber (ACM), fluororubber (FKM), chlorosulfonated polyethylene (CSM), hydrin rubber (CO, ECO, etc.) ), Silicone (Q), urethane (U), ethylene-vinyl acetate copolymer (EVA), polyethylene resin, epoxy resin, polyamide and the like.

  Examples of the monomer component having an unsaturated carbon-carbon double bond include liquid rubber and butadiene diol.

  For example, in the case of urethane, an unsaturated carbon-carbon double bond can be introduced into urethane by adding liquid butadiene diol to the two-component urethane coating.

  When mixing low molecular weight components with unsaturated carbon-carbon double bonds and oligomer components with unsaturated carbon-carbon double bonds, these components that are only mixed with the polymer component will bleed from the rubber elastic layer. In order to prevent this, for example, a material having an SP value (solubility parameter) close to that of the polymer component is selected, or the molecular weight of these components is increased as much as possible (for example, a material having a molecular weight of 2000 or more is used). preferable.

  When surface treatment A is performed, in the case of simultaneous contact, the a1 component added to the unsaturated carbon-carbon double bond of the a2 component is added to the unsaturated carbon-carbon double bond of the rubber elastic layer. To do. In the case of step contact, trichloroisocyanuric acid undergoes an addition reaction with the unsaturated carbon-carbon double bond of the rubber elastic layer, and then the N-Cl bond portion remaining in the isocyanuric acid skeleton, the unsaturated carbon-a2 component Addition reaction to carbon double bond. Thereby, surface modification is given to a rubber elastic layer. As a result, the surface of the rubber elastic layer has, for example, a structure represented by the following formula 2.

  Formula 2 shows an example in which an N—Cl bond portion remains in the isocyanuric acid skeleton. Examples of other structures that the surface of the rubber elastic layer may have include an addition reaction with other unsaturated carbon-carbon double bonds of the rubber elastic layer at the N—Cl bond portion remaining in the structure shown in Formula 2. And a structure in which an addition reaction is performed on the unsaturated carbon-carbon double bond of the a2 component at the N—Cl bond portion remaining in the structure shown in Formula 2. The surface of the rubber elastic layer has only one of these structures or two or more of these structures. In addition, in the case where two a2 components are bonded to one isocyanuric acid skeleton, the two organic groups may have different functional groups, or may have the same functional group. good.

  By performing the surface treatment A, an organic group having a specific functional group is bonded to the surface of the rubber elastic layer through an isocyanuric acid skeleton, and the surface of the rubber elastic layer is modified. The organic group having a specific functional group is bonded to the N atom of the isocyanuric acid skeleton. The isocyanuric acid skeleton is bonded to the surface of the rubber elastic layer with N atoms.

  Chlorine atoms are also bonded to the surface of the rubber elastic layer. In the rubber elastic layer, chlorine atoms exist not only on the surface but also on the inside, but the abundance of chlorine atoms increases from the inside toward the surface.

  The point where the isocyanuric acid skeleton is bonded to the surface of the rubber elastic layer, the point where an organic group having a specific functional group is bonded via the isocyanuric acid skeleton, the point where chlorine atoms are bonded, the surface from the inside The point where the abundance of chlorine atoms inclines toward the surface can be sufficiently estimated from the surface treatment A, but can be detected by XPS or NMR, for example.

  The specific functional group is a functional group for imparting a specific function to the surface of the rubber elastic layer. As functional groups, silicone groups, perfluoroalkyl groups, ester groups, amide groups, imide groups, ether groups, aryl groups, isocyanate groups, azo groups, diazo groups, nitro groups, epoxy groups, carbonyl groups, heterocyclic groups, Examples include mesoionic groups, halogen groups, amino groups, imino groups, alkyl groups, sulfonic acid groups, hydroxy groups, acyl groups, formyl groups, carboxylic acid groups, urea groups, and cyano groups. In the organic group, only one type of these functional groups may be included, or two or more types of functional groups may be included.

  Examples of the heterocyclic group include a pyridyl group, an imidazole group, and an oxazole group. In addition, examples of the mesoionic group include a sydnone group and a munhenone group.

  In the case where the specific functional group is, for example, a silicone group, the surface of the rubber elastic layer can have a low friction property as a specific function as well as an excellent releasability with respect to the deposit. When the specific functional group is, for example, a silicone group or a perfluoroalkyl group, the surface of the rubber elastic layer can have antifouling property as a specific function. When the specific functional group is, for example, an amide group or an ester group, the surface of the rubber elastic layer can have chargeability (chargeability) as a specific function. When the specific functional group is, for example, an ether group, the surface of the rubber elastic layer can have an antistatic property that lowers the electrical resistance of the surface as a specific function. Even in the case where the specific functional group is a functional group other than these, the surface of the rubber elastic layer can have a specific function based on each functional group as well as excellent releasability with respect to the deposit.

  Examples suitable for the a2 component are shown in Formulas 3-6. Formulas 3 and 4 are examples in which the organic group has a silicone group and an ester group. Formula 5 is an example in which the organic group has an alkyl group and an ester group. Formula 6 is an example in which the organic group has an alkyl group.

  The molecular weight of the component a2 is preferably in the range of 50 to 10,000. More preferably, it exists in the range of 70-5000. If the molecular weight is smaller than 50, the volatility of the a2 component tends to be large, so that it is difficult to handle. On the other hand, if the molecular weight is greater than 10,000, the reactivity with the a1 component tends to decrease, and it is difficult to impart a desired function to the rubber elastic layer.

  When the blending amount of the a1 component is a1 and the blending amount of the a2 component is a2, the blending ratio of the a1 component and the a2 component is in a molar ratio within the range of a1 / a2 = 1/2 to 1 / 0.01. It is preferable that When the blending amount of the a2 component is too small and falls outside the above range, the effect of imparting a specific function based on a specific functional group of the a2 component to the rubber elastic layer tends to be lowered. On the other hand, if the blending amount of the a1 component is too small and falls outside the above range, the reactivity with respect to the rubber elastic layer is likely to decrease, so that it is difficult to sufficiently impart a desired function to the rubber elastic layer. Or durability cannot be obtained.

  In the surface treatment A, a solvent for dissolving or dispersing the a1 component and the a2 component can be used. The solvent is not particularly limited, but ether solvents (THF, diethyl ether, dioxane, etc.), ester solvents (ethyl acetate, butyl acetate, etc.), ketone solvents (acetone, MEK, etc.), amides, etc. Examples include solvents (DMF, DMAC, NMP, etc.), tertiary alcohols (tert-butyl alcohol, etc.), water and the like. These may be used alone or in combination of two or more. As the solvent, for example, two types of solvents may be used: a solvent for dissolving or dispersing the a1 component and a solvent for dissolving or dispersing the a2 component.

  As a density | concentration of a1 component with respect to a solvent, it is preferable to exist in the range of 1-10 mass parts with respect to 100 mass parts of solvents. More preferably, it exists in the range of 2-5 mass parts. When the concentration of the a1 component is too low and falls outside the above range, the reactivity with respect to the rubber elastic layer is likely to decrease, so that it is difficult to sufficiently impart a desired function to the rubber elastic layer. On the other hand, when the concentration of the a1 component is too high and falls outside the above range, the processing unevenness with respect to the rubber elastic layer tends to increase.

  The surface modifier containing the a1 component, the surface modifier containing the a2 component, the surface modifier containing the a1 component and the a2 component contain other components in addition to the a1 component and the a2 component. May be. Examples of other components include acids, bases, catalysts such as metal salts, and surfactants.

  As a method of bringing the a1 component and a2 component into contact with the surface of the rubber elastic layer, for example, the surface modifier is configured to be liquid, and the surface of the rubber elastic layer is directly immersed in the liquid surface modifier. Or by applying a liquid surface modifier to the surface of the rubber elastic layer.

  As the temperature of the surface modifier to be contacted, normal temperature is sufficient, but it is preferably in the range of 20 to 100 ° C, more preferably in the range of 25 to 70 ° C. When the temperature of the surface modifier is less than 20 ° C., the reactivity between the substrate in the surface modifier and the unsaturated carbon-carbon double bond existing on the surface of the rubber elastic layer tends to be lowered. On the other hand, when the temperature of the surface modifier exceeds 100 ° C., uneven processing tends to occur.

  The immersion time does not require a long time. For example, about 10 seconds to 1 hour is sufficient. More preferably, it is within the range of 30 seconds to 5 minutes. When the immersion time is less than 10 seconds, the contact time is too short and it is difficult to obtain a sufficient surface treatment effect. On the other hand, even if the immersion time exceeds 1 hour, the improvement of the surface treatment effect cannot be expected and the productivity is lowered.

  After the rubber elastic layer is immersed in the surface modifier, the rubber elastic layer is preferably lifted from the surface modifier, washed and dried. The cleaning liquid is not particularly limited as long as it is easily mixed with the solvent of the surface modifier and can wash away the unreacted substrate. For example, the same solvent as one or more of the solvents in the surface modifier can be used.

  The cleaning time does not require a long time. For example, about 10 seconds to 10 minutes is sufficient. If the cleaning time is less than 10 seconds, it is too short and it is difficult to obtain a sufficient cleaning effect. Therefore, an unreacted substrate tends to remain on the surface of the rubber elastic layer. On the other hand, even if the cleaning time exceeds 10 minutes, the improvement of the cleaning effect cannot be expected and the productivity is lowered.

  As the drying temperature, room temperature (room temperature) is sufficient, but it is preferably in the range of room temperature to 250 ° C, more preferably in the range of room temperature to 100 ° C. When the drying temperature is lower than room temperature, the solvent is difficult to volatilize and has a long drying time. On the other hand, when the drying temperature is higher than 250 ° C., the rubber elastic layer is likely to be deteriorated. Moreover, the energy required for drying becomes too large.

(B) is a surface treatment B in which the following b1 component and b2 component are brought into contact with the surface of the rubber elastic layer.
(B1) Compound having two or more thiol groups (b2) A functional group capable of reacting with the thiol group and a functional group for imparting a function to the surface of the rubber elastic layer (hereinafter, referred to as a specific functional group). And a compound having

  In the component b1, as the compound having two or more thiol groups, a chain thiol compound having two or more thiol groups bonded to a chain structure, or a cyclic thiol having two or more thiol groups bonded to a cyclic structure A compound etc. can be mentioned. The compound having two or more thiol groups may be only one of a plurality of types of chain thiol compounds and a plurality of types of cyclic thiol compounds, or may be a mixture of two or more types.

  In the chain thiol compound, the chain structure may be composed of a hydrocarbon chain, or may have an ester bond or an ether bond in the hydrocarbon chain. The chain thiol compound preferably has a relatively large molecular weight. More specifically, the molecular weight is preferably in the range of 200 to 1,000.

  In the chain thiol compound, the thiol group may be a primary thiol group or a secondary thiol group. More preferably, it is a secondary thiol group from the viewpoint of increasing stability of a compound having two or more thiol groups by increasing the steric hindrance around the thiol group.

  Examples of chain thiol compounds having two or more secondary thiol groups include 1,4-bis (3-mercaptobutyryloxy) butane and 1,3,5-tris (3-mercaptobutyryloxyethyl) -1. , 3,5-triazine-2,4,6- (1H, 3H, 5H) -trione, pentaerythritol tetrakis (3-mercaptobutyrate), and the like.

  In the cyclic thiol compound, examples of the cyclic structure include a triazine ring, a benzene ring, a heterocyclic ring, a condensed ring, a spiro ring, and a carbon ring. The cyclic thiol compound preferably has a relatively large molecular weight. More specifically, the molecular weight is preferably in the range of 200 to 1,000.

  Examples of cyclic thiol compounds having two or more thiol groups include trithiocyanuric acid, 1,2-benzenedithiol, 1,4-benzenedithiol, 1,3,5-benzenetrithiol, 1,5-dimercaptonaphthalene, and the like. Can be mentioned.

  As a compound having two or more thiol groups, trithiocyanuric acid is particularly preferable. When trithiocyanuric acid is used, the dielectric constant of the rubber elastic layer can be increased due to the effect of non-conjugated electrons, and the chargeability and discharge performance of the rubber elastic layer can be improved.

  In the b2 component, examples of the functional group capable of reacting with the thiol group include an unsaturated carbon-carbon double bond, a halogen group, an epoxy group, a hydroxyl group, an isocyanate group, a methylol group, a carboxyl group, and a carbonyl group. The specific functional group is a functional group for imparting a specific function to the surface of the rubber elastic layer, and examples thereof include those described in the surface treatment A. The b2 component may be composed of only one kind of compound or may be composed of a mixture of two or more kinds of compounds.

  In the surface treatment B, the b1 component and the b2 component may be contacted simultaneously with the surface of the rubber elastic layer (simultaneous contact), or the b2 component may be contacted after contacting the b1 component (step contact). . In the former case, a surface modifier containing a b1 component and a b2 component is used. In the latter case, a surface modifier containing the b1 component and a surface modifier containing the b2 component are used stepwise.

When the b1 component and the b2 component are mixed, the b1 component and the b2 component react at room temperature or under heating conditions. An example of the reaction is shown in the following formula 7 by giving trithiocyanuric acid as an example of the component b1, and a compound having an unsaturated carbon-carbon double bond and a specific functional group as an example of the component b2. In Formula 7, R ^{1 to} R ⁴ are the same as those shown in Formula 1.

  The surface treatment B can be applied to a rubber elastic layer formed of a polymer containing an organic component having a functional group that reacts with a thiol group. Examples of the functional group that reacts with the thiol group include an unsaturated carbon-carbon double bond, a halogen group, an epoxy group, a hydroxyl group, an isocyanate group, a methylol group, a carboxyl group, and a carbonyl group. Since the surface treatment B can be applied to a polymer containing organic components having various functional groups, the application range is wide.

  The organic component may be a polymer component of the rubber elastic layer, or may be a low molecular weight component or an oligomer component mixed with the polymer component. The polymer component may be any of rubber, resin, and elastomer. The polymer component may be only one of these, or a mixture of two or more.

  Examples of the polymer component having an unsaturated carbon-carbon double bond include those described in the surface treatment A. Examples of the polymer component having a halogen group include hydrin rubber (CO, ECO, etc.), chloroprene rubber (CR), and the like. In addition to these, examples of the polymer component having a functional group that reacts with a thiol group (-SH group) include an epoxy resin, polyurethane, and polyamide.

  When mixing low molecular weight components that have functional groups that react with thiol groups and oligomer components that have functional groups that react with thiol groups, these components that are only mixed in the polymer component will bleed from the rubber elastic layer. In order to prevent this, for example, it is preferable to select a material having an SP value (solubility parameter) close to that of the polymer component or to increase the molecular weight of these components as much as possible (for example, use a material having a molecular weight of 2000 or more). .

  When the surface treatment B is performed, a compound having two or more thiol groups is bonded to one or more functional groups that react with the thiol group of the rubber elastic layer through one or more SH bond portions. At this time, the compound having two or more thiol groups may have one or more SH bond portions remaining without being bonded to the functional group that reacts with the thiol group of the rubber elastic layer. A functional group capable of reacting with the thiol group of the b2 component is bonded to a part or all of the remaining SH bond portion.

  An organic group having a specific functional group is bonded to a thiol group of a compound having two or more thiol groups. Moreover, the compound which has 2 or more of thiol groups couple | bonds with the surface of a rubber elastic layer with a thiol group. That is, by performing the surface treatment B, an organic group having a specific functional group is bonded to the surface of the rubber elastic layer via a compound having two or more thiol groups. Modification is applied.

  An unsaturated carbon-carbon double bond is given as a functional group that reacts with the thiol group of the rubber elastic layer, trithiocyanuric acid is given as an example of the b1 component, and an unsaturated carbon-carbon double bond and a specific function are given as examples of the b2 component. An example of a structure obtained on the surface of the rubber elastic layer as a result of the surface modification by using a compound having a group is shown in the following formula 8.

Formula 8 shows an example in which one of the three thiol groups of trithiocyanuric acid remains. In this example, as an example of another structure that the surface of the rubber elastic layer may have, a thiol group remaining in the structure shown in Formula 8 is added to another unsaturated carbon-carbon double bond of the rubber elastic layer. And a structure in which a thiol group remaining in the structure represented by Formula 8 is addition-reacted with an unsaturated carbon-carbon double bond of the b2 component. In this example, the surface of the rubber elastic layer has only one of these structures or two or more of these structures. In Formula 8, R ^{1 to} R ⁴ are the same as those shown in Formula 1.

  Regarding the point that a compound having two or more thiol groups is bonded to the surface of the rubber elastic layer, the point that an organic group having a specific functional group is bonded to a compound having two or more thiol groups, etc. Although it can be sufficiently estimated from the processing B, it can be detected by, for example, XPS or NMR.

  The molecular weight of component b2 is preferably in the range of 50 to 10,000. More preferably, it exists in the range of 70-5000. When the molecular weight is less than 50, the volatility of the b2 component tends to be large, and it is difficult to handle. On the other hand, if the molecular weight is greater than 10,000, the reactivity with the b1 component tends to decrease, so that it is difficult to impart a desired function to the rubber elastic layer.

  When the blending amount of the b1 component is b1 and the blending amount of the b2 component is b2, the blending ratio of the b1 component and the b2 component is in the range of b1 / b2 = 1/2 to 1 / 0.01 in terms of mol ratio. It is preferable that When the blending amount of the b2 component is too small and falls outside the above range, the effect of imparting a specific function based on a specific functional group of the b2 component to the rubber elastic layer tends to be lowered. On the other hand, when the blending amount of the component b1 is too small and falls outside the above range, the reactivity with respect to the rubber elastic layer is likely to decrease, so that it is difficult to sufficiently impart a desired function to the rubber elastic layer. In addition, the b2 component may bleed.

  In the surface treatment B, a solvent for dissolving or dispersing the b1 component and the b2 component can be contained. The solvent is not particularly limited, but ether solvents (THF, diethyl ether, dioxane, etc.), ester solvents (ethyl acetate, butyl acetate, etc.), ketone solvents (acetone, MEK, etc.), amides, etc. Examples include solvents (DMF, DMAC, NMP, etc.), tertiary alcohols (tert-butyl alcohol, etc.), water and the like. These may be used alone or in combination of two or more. As the solvent, for example, two types of solvents may be used: a solvent for dissolving or dispersing the b1 component and a solvent for dissolving or dispersing the b2 component.

  As a density | concentration of b1 component with respect to a solvent, it is preferable to exist in the range of 1-10 mass parts with respect to 100 mass parts of solvents. More preferably, it exists in the range of 2-5 mass parts. When the concentration of the b1 component is too low and falls outside the above range, the reactivity with respect to the rubber elastic layer is likely to decrease, so that it is difficult to sufficiently impart a desired function to the rubber elastic layer. On the other hand, when the concentration of the b1 component is too high and falls outside the above range, the processing unevenness with respect to the rubber elastic layer tends to increase.

  The surface modifier containing the b1 component, the surface modifier containing the b2 component, the surface modifier containing the b1 component and the b2 component contain other components in addition to the b1 component and the b2 component. May be. Examples of other components include acids, bases, catalysts such as metal salts, and surfactants.

  As a method of bringing the b1 component and b2 component into contact with the surface of the rubber elastic layer, for example, the surface modifier is configured to be liquid, and the surface of the rubber elastic layer is directly immersed in the liquid surface modifier. Or by applying a liquid surface modifier to the surface of the rubber elastic layer.

  The temperature of the liquid containing the surface modifier when dipping the rubber elastic layer or coating the surface of the rubber elastic layer is preferably within the range of -20 to 60 ° C. More preferably, it exists in the range of 0-40 degreeC. At low temperatures, the rubber elastic layer is not easily impregnated with the surface modifier. Processing irregularities are likely to occur at high temperatures.

  The immersion time does not require a long time. For example, about 5 seconds to 1 hour is sufficient. More preferably, it is in the range of 10 seconds to 5 minutes. When the immersion time is less than 5 seconds, the contact time is too short, and it is difficult to obtain a sufficient surface treatment effect. On the other hand, even if the immersion time exceeds 1 hour, the improvement of the surface treatment effect cannot be expected and the productivity is lowered.

  After the surface modifier is brought into contact with the surface of the rubber elastic layer, heat treatment is performed in order to increase the reactivity between the thiol group of the surface modifier and the surface of the rubber elastic layer to facilitate the completion of the reaction. Is preferred. As temperature of heat processing, the inside of the range of 70-250 degreeC is preferable. More preferably, it exists in the range of 100-180 degreeC. The reaction takes a long time at low temperatures. The rubber elastic layer is likely to deteriorate at high temperatures. Moreover, energy consumption becomes too large.

(C) is a surface treatment C in which the following c1 component and c2 component are brought into contact with the surface of the rubber elastic layer.
(C1) X ¹ (OX ² ) _n and one or more selected from compounds having a —CONX ² — bond in the molecule (c2) BF ₃

In the formula, X ¹ represents a hydrogen atom, an alkali metal element, an alkaline earth metal element or an alkyl group, X ² represents a halogen atom, and n represents an integer identical to the valence of X ¹ . X ² represents a halogen atom (F, Cl, Br, I).

  In the surface treatment C, the c1 component and the c2 component may be brought into contact with the surface of the rubber elastic layer simultaneously (simultaneous contact method), or the c1 component or the c2 component is brought into contact with each other and then the other is brought into contact. (Step contact method). In the former case, a surface modifier containing a c1 component and a c2 component is used. In the latter case, the surface modifier containing the c1 component and the surface modifier containing the c2 component are used stepwise.

  Surface treatment C can be applied to a rubber elastic layer formed of a polymer containing an organic component having an unsaturated carbon-carbon double bond. Examples of the polymer containing an organic component having an unsaturated carbon-carbon double bond include the same as those described in the surface treatment A.

  By performing the surface treatment C, the unsaturated carbon-carbon double bond of the rubber elastic layer is halogenated, and a structure represented by the following formulas 9 to 10 is formed on the surface portion of the rubber elastic layer.

  The structures represented by Formulas 9 to 10 are preferably present so as to occupy most of the surface of the rubber elastic layer, but may not necessarily exist on the entire surface of the rubber elastic layer. If it is in the range with the effect of this invention, the structure shown to Formula 9-10 may exist partially in the surface of a rubber elastic layer.

  Moreover, the structure shown to Formula 9-10 may exist not only in the surface part of a rubber elastic layer but in the inside of a rubber elastic layer. At this time, the rubber elastic layer may be distributed so as to incline so as to decrease or increase the existence ratio of the structures shown in Formulas 9 to 10 from the surface of the rubber elastic layer to the inside, or from the surface of the rubber elastic layer to the inside. May be distributed at substantially the same existence ratio over a certain distance. In addition, it can confirm that it has the structure shown to Formula 9-10 if a roll surface is analyzed by X-ray photoelectron spectroscopy (XPS), a nuclear magnetic resonance method (NMR), etc.

  In the c1 component, specific examples of the alkali metal element include lithium, sodium, potassium, and the like. Specific examples of the alkaline earth metal element include magnesium and calcium.

  Specific examples of the alkyl group in the component c1 include a methyl group, an ethyl group, a tertiary butyl group, a trifluoromethyl group, and the like. From the viewpoint of structural stability, a tertiary butyl group is preferable.

In the c1 component, specific examples of the halogen atom X ² include F, Cl, Br, I, and the like. Preferably, F, Cl, and the like are used from the viewpoint of being likely to be stably present on the surface of the rubber elastic layer after the reaction.

More specifically, as the compound represented by X ¹ (OX ² ) _n in the component c1, for example, alkyl such as methyl hypochloride, ethyl hypochloride, tertiary butyl hypochloride, trifluoromethyl hypochloride, etc. Alkyl hypohalides such as hypochloride, methyl hypofluoride, ethyl hypofluoride, tertiary butyl hypofluoride, alkyl hypofluoride such as trifluoromethyl hypofluoride, hypochlorous acid and hypochlorous acid Examples thereof include hypochlorites such as lithium, sodium hypochlorite, magnesium hypochlorite, and potassium hypochlorite. These may be used alone or in combination of two or more.

In the component c1, as a compound having a —CONX ² — bond in the molecule, more specifically, for example, acid imide halogen compounds such as N-chlorosuccinimide, N-chlorophthalimide, N-bromosuccinimide, and N-bromophthalimide Examples thereof include isocyanuric acid halides such as trichloroisocyanuric acid and dichloroisocyanuric acid, and halogenated hydantoins such as dichlorodimethylhydantoin.

  When using either the above-mentioned step contact method or simultaneous contact method, a liquid containing at least each compound may be used. There are advantages such as easy contact with the rubber surface evenly. Specifically, for example, in the case of the step contact method, a treatment liquid in which at least the c1 component or the c2 component is dissolved and / or dispersed in an appropriate aqueous solvent or organic solvent may be used. On the other hand, in the case of the simultaneous contact method, a treatment liquid in which at least the c1 component and the c2 component are dissolved and / or dispersed in an appropriate aqueous solvent or organic solvent may be used.

  Specific examples of the aqueous solvent include water, and specific examples of the organic solvent include toluene, acetone, methyl ethyl ketone, tetrahydrofuran, ethyl acetate, butyl acetate, hexane, methanol, ethanol, and propanol. And tertiary butanol, isopropyl alcohol, diethyl ether, N-methylpyrrolidone and the like. These may be used alone or in combination of two or more.

  Further, the content of the c1 component and / or the c2 component contained in the treatment liquid is particularly limited as long as the structure represented by the above formula can finally exist on at least the surface portion of the rubber elastic layer. is not. It can be adjusted as necessary.

  In the case of the above-described step contact method, the content of the c1 component contained in the treatment liquid containing the c1 component can be specifically exemplified by, for example, 40% by mass as its preferred upper limit value. On the other hand, as a preferable lower limit value that can be combined with this upper limit value, specifically, for example, 0.01% by mass can be exemplified.

  Further, in the case of the step contact method, specifically, the content of the c2 component contained in the treatment liquid containing the c2 component can be exemplified by 40% by mass as a preferable upper limit value. On the other hand, as a preferable lower limit value that can be combined with this upper limit value, specifically, for example, 0.01% by mass can be exemplified.

  When the content of the c1 component or c2 component contained in each treatment liquid is within the above range, the balance between the reactivity to rubber and the rubber hardness is excellent.

  In the case of the simultaneous contact method, the content of the c1 component contained in the treatment liquid containing the c1 component and the c2 component is specifically exemplified by, for example, 40% by mass as a preferable upper limit value. Can do. On the other hand, as a preferable lower limit that can be combined with this upper limit, specifically, for example, 0.01% by mass can be exemplified. Similarly, specific examples of the content of the c2 component include, for example, 40% by mass as a preferable upper limit thereof. On the other hand, as a preferable lower limit that can be combined with this upper limit, specifically, for example, 0.01% by mass can be exemplified.

  This is because when the contents of the c1 component and the c2 component contained in the treatment liquid containing the c1 component and the c2 component are within these ranges, the balance between the reactivity to rubber and the rubber hardness is excellent.

  In this case, the c1 component / c2 component (weight ratio) can be specifically exemplified by 9 (90/10) as a preferable upper limit value. On the other hand, specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 0.01 (1/99).

  This is because when the c1 component / c2 component (weight ratio) is within these ranges, the reactivity between the unsaturated bond and the effect of introducing fluorine atoms is excellent.

  The surface treatment C can basically be performed at around room temperature, but the contact temperature may be adjusted as necessary within a range that does not adversely affect the formation of the structures shown in Formulas 9-10. However, when the contact temperature is excessively high, the reaction proceeds excessively, and there is a tendency that the surface of the rubber elastic layer is cracked or excessively hard. On the other hand, if the contact temperature is excessively lowered, the reaction with the rubber mainly constituting the rubber elastic layer tends to decrease. Therefore, it is preferable to select the contact temperature in consideration of these.

  In the surface treatment C, the contact time with the above compound varies depending on the concentration of the treatment liquid and the like, but can be appropriately adjusted as necessary within a range that does not adversely affect the formation of the structures represented by Formulas 9 to 10. it can. However, if the contact time is excessively long, the roll production efficiency tends to decrease. On the other hand, when the contact time is excessively shortened, there is a tendency that the reaction with the rubber mainly constituting the rubber elastic layer becomes insufficient. Therefore, it is preferable to select the contact time in consideration of these. Preferably, the contact time is in the range of 20 seconds to 60 seconds in consideration of productivity and reactivity.

  Moreover, the method of making the said process liquid contact the rubber elastic layer surface is not specifically limited, A various method is employable. Specifically, for example, a method of immersing the roll in the treatment liquid, a method of applying the treatment liquid to the roll, a method of spraying the treatment liquid on the roll, and the like can be exemplified. These may be performed in combination of one or two or more.

  By the surface treatment C, the unsaturated bond contained in the rubber on the surface portion of the rubber elastic layer is cut, and a halogen atom derived from the c1 component and a fluorine atom derived from the c2 component are introduced into the molecular structure of the rubber.

  After performing the surface treatment C, the surface of the rubber elastic layer may be washed away with a liquid containing water. Thereby, the c1 component, c2 component, etc. adhering excessively to the surface of the rubber elastic layer are washed away, and the roll surface is cleaned. Furthermore, hydroxyl groups are introduced into the molecular structure of the rubber on at least the surface portion of the rubber elastic layer. In addition, when the treatment liquid containing water is used in the surface treatment C, it is presumed that some hydroxyl groups are introduced into the molecular structure of the rubber by performing the surface treatment C. Therefore, the hydroxyl group derived from water is introduced into the molecular structure of the rubber on at least the surface portion of the rubber elastic layer by performing the surface treatment C or by subsequent cleaning.

  (D) is a surface treatment D with ultraviolet rays. The surface treatment D can be performed in an inert gas such as nitrogen gas or argon gas, or in the atmosphere.

  When surface modification is performed with ultraviolet rays, any ultraviolet irradiation device known in the art can be used as long as it is a known ultraviolet irradiation device that meets the object of the present invention. Specifically, UB031-2A / BM (trade name) manufactured by Eye Graphics Co., Ltd. can be exemplified.

The ultraviolet irradiation conditions are appropriately determined according to the type of the ultraviolet irradiation apparatus used, but generally the irradiation intensity is about 20 to 150 mW / cm ² , and the distance between the ultraviolet light source and the elastic layer surface is 20 to. Conditions of about 80 mm and irradiation time: about 5 to 360 seconds are employed.

  According to the surface treatments A to C, the surface of the rubber elastic layer 14 is formed with covalent bonds of molecules and atoms that enhance toner releasability and other functions, so that these functions are also excellent in durability. Further, the surface treatment D is also excellent in the durability of the function of improving the toner releasability.

In the present invention, the surface of the rubber elastic layer 14 formed with a large number of convex portions 16 is subjected to surface modification without forming a coating layer. The fine uneven shape is maintained as it is. According to the mold transfer, on the roll surface (the surface of the rubber elastic layer 14), besides the convex portion 16 (16a) in which the ratio of the height h to the diameter φ ₁ (h / φ ₁ ) is 0.5 or more. The convex part 16 (16b) of the height lower than this exists. Since the minute convex portions 16 (16b) remain on the surface of the rubber elastic layer 14 without disappearing, it is possible to suppress the occurrence of a portion where the convex portions 16 are sparse on the surface of the rubber elastic layer 14. That is, since the variation in the density of the convex portions 16 is less likely to occur on the surface of the rubber elastic layer 14, the variation in the density of the obtained image can be suppressed. Thereby, a fine image can be obtained.

  Next, materials for the shaft body 12 and the rubber elastic layer 14 constituting the developing roll 10 of the present invention will be described. The material of the mold 20 will be described.

  An example of the shaft body 12 is a conductive shaft. Examples of the conductive shaft include a metal solid body, a metal cylindrical body, and a metal plated body. Examples of the metal include aluminum and stainless steel. An adhesive, a primer, or the like may be applied to the outer peripheral surface of the shaft body 12 for the purpose of improving the adhesiveness with the rubber elastic layer 14. The adhesive or primer can be made conductive as required.

  What is necessary is just to select suitably as a rubber material of the rubber elastic layer 14 according to the kind of surface treatment. Specific examples include silicone rubber, urethane rubber, butadiene rubber, hydrin rubber, and nitrile rubber. Of these, silicone rubber and urethane rubber are preferable from the viewpoint of excellent recovery of elastic deformation caused by pressing of a mating member such as a layer forming blade or a photoreceptor (good anti-sagging property). Silicone rubber is particularly preferable because it hardly changes in volume with respect to environmental changes such as temperature change and humidity change, and also has an advantage of small fluctuations in the outer diameter of the roll due to environmental changes.

  The rubber elastic layer 14 may include a conductive agent, a filler, an extender, a reinforcing agent, a processing aid, a curing agent, a vulcanization accelerator, a crosslinking agent, a crosslinking aid, an antioxidant, a plasticizer, as necessary. Various additives such as ultraviolet absorbers, pigments, silicone oils, auxiliaries, and surfactants may be appropriately added. Examples of the conductive agent include general conductive agents such as an electronic conductive agent such as carbon black and an ionic conductive agent such as a quaternary ammonium salt.

  The rubber elastic layer 14 may be a foam or a solid body. The rubber elastic layer 14 preferably has a thickness in the range of 0.1 to 10 mm. More preferably, it exists in the range of 1-5 mm.

  In the developing roll 10 of the present invention, another layer having a function of adjusting resistance or the like may be provided inside the rubber elastic layer 14.

  The material of the mold base 22 is not particularly limited, and examples thereof include a carbon steel material such as S55C, an aluminum chrome molybdenum steel material such as SACM645, an aluminum alloy such as A5056, and aluminum. Further, a resin material may be used.

  The developing roll 10 of the present invention is a developing roll incorporated in an electrophotographic apparatus such as a copying machine, a printer, or a facsimile employing an electrophotographic system, and is disposed around a photosensitive drum incorporated in the electrophotographic apparatus. Is.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Example 1
<Preparation of mold for forming rubber elastic layer>
Electroless plating is performed on the inner surface of a cylindrical mold base with an inner diameter of 16 mm using the following plating solution under the conditions of a plating solution pH of 8, a plating solution temperature of 80 ° C., and a plating time of 120 minutes. An included electroless plating layer was formed. (Plating thickness 16 μm). Thereafter, the acrylic particles taken into the electroless plating layer were dissolved and removed with acetone to obtain a mold having a large number of recesses on the inner surface of the mold.

[Preparation of plating solution]
Using a cationic surfactant (lauryltrimethylammonium chloride), a resin particle dispersion in which acrylic particles <1> (manufactured by Negami Kogyo Co., Ltd., Art Pearl GR600, average particle size 10 μm) is dispersed in water is added to the basic plating solution. Thus, a plating solution having the following composition was prepared.

[Composition of plating solution]
Nickel sulfate hexahydrate 26g / L
Sodium hypophosphite monohydrate (reducing agent) 32 g / L
Glycine (complexing agent) 7.5g / L
Sodium citrate dihydrate (complexing agent) 30 g / L
Acrylic particles <1> 20 g / L
Cationic surfactant 0.1g / L

The obtained mold was cut in the circumferential direction, and an enlarged photograph (1000 times) of this section was taken using a microscope (manufactured by Nakaden, Mx-1200E) to take a sectional photograph of the plating film. This is shown in FIG. According to FIG. 8, the surface of the plating film formed on the inner peripheral surface of the cylindrical mold base has a recess having a ratio of the depth d ₂ to the diameter φ ₂ (d ₂ / φ ₂ ) of 1 or more. It can be confirmed that many are formed.

<Preparation of developing roll>
[Production of base roll]
A solid cylindrical iron bar having a diameter of 10 mm was prepared as a shaft serving as a core metal, and an adhesive was applied to the outer peripheral surface of the core metal. And as a material for forming the rubber elastic layer, liquid silicone rubber (X-34-264A / B, manufactured by Shin-Etsu Chemical Co., Ltd., mixed mass ratio 30/70) containing a conductive agent is injected into the mold, After being cured by heating at 190 ° C. for 30 minutes, the mold was removed. As a result, a base roll was obtained in which a rubber elastic layer (thickness 3 mm) containing silicone rubber with C = C bonds remaining on the surface was integrally formed along the outer peripheral surface of the shaft body.

[Surface modification of base roll]
Using the following surface modifier A, the base roll was immersed for 30 seconds at 25 ° C. so that the roll surface was immersed in the surface modifier A, and the roll surface was washed with ethyl acetate at 25 ° C. for 30 seconds, then 100 Dry at 10 ° C. for 10 minutes. Thereby, the developing roll of Example 1 was obtained.

[Preparation of surface modifier A]
5 parts by mass of trichloroisocyanuric acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 1 part by mass of C = C bond-containing silicone oil (manufactured by Shin-Etsu Silicone, X-22-174DX), 80 parts by mass of tert-butyl alcohol, and ethyl acetate Surface modifier A was prepared by mixing 20 parts by mass.

(Example 2)
[Surface modification of base roll]
A base roll having the same configuration as in Example 1 was used, and the surface modification of the base roll was performed using the following surface modifier B instead of the surface modifier A. More specifically, after immersing the base roll at 25 ° C. for 30 seconds so that the roll surface was immersed in the following surface modifier B, the surface of the base roll was heat-treated at 150 ° C. for 20 minutes. Thereby, the developing roll of Example 2 was obtained.

[Preparation of surface modifier B]
By mixing 5 parts by mass of trithiocyanuric acid, 1 part by mass of C = C bond-containing silicone oil (X-22-174DX, manufactured by Shin-Etsu Silicone Co., Ltd.) and 100 parts by mass of tetrahydrofuran (THF), surface modifier B Was prepared.

Example 3
[Surface modification of base roll]
A base roll having the same configuration as in Example 1 was used, and the surface modification of the base roll was performed using the following surface modifier C instead of the surface modifier A. More specifically, after immersing the base roll at 25 ° C. for 30 seconds so that the roll surface was immersed in the following surface modifier C, the surface of the base roll was heat-treated at 150 ° C. for 20 minutes. Thereby, the developing roll of Example 3 was obtained.

[Preparation of surface modifier C]
5 parts by mass of a bifunctional thiol compound (manufactured by Showa Denko KK, KarenzMT BD1, secondary thiol group), 1 part by mass of C = C bond-containing silicone oil (X-22-174DX, manufactured by Shin-Etsu Silicone), and tetrahydrofuran ( Surface modifier C was prepared by mixing 100 parts by weight of THF).

Example 4
[Surface modification of base roll]
A base roll having the same configuration as in Example 1 was used, and the surface modification of the base roll was performed using the following surface modifier D instead of the surface modifier A. More specifically, the base roll was immersed for 60 seconds at 25 ° C. so that the roll surface was immersed in the following surface modifier D, and then washed with water for 30 seconds. As a result, a developing roll of Example 4 was obtained.

[Preparation of surface modifier D]
5 parts by mass of tert-butyl hypochlorite (manufactured by Tokyo Chemical Industry Co., Ltd.) and 10 parts by mass of boron trifluoride-diethyl ether (containing 48% by mass of BF ₃ , manufactured by Kanto Chemical Co., Ltd.) Surface modifier D was prepared by dissolving in 100 g of methyl ethyl ketone.

(Example 5)
[Surface modification of base roll]
The base roll having the same configuration as that of Example 1 was used, and the surface modification of the base roll was performed using the following surface modifier E instead of the surface modifier A. More specifically, the base roll was immersed for 60 seconds at 25 ° C. so that the roll surface was immersed in the following surface modifier E, and then washed by immersing in water for 30 seconds. As a result, a developing roll of Example 5 was obtained.

[Preparation of surface modifier E]
And trithiocyanuric acid 5 parts by weight, boron trifluoride - diethyl ether (BF ₃ to 48 mass% content, Kanto Kagaku Co., Ltd.) and 10 parts by mass, by dissolving in methyl ethyl ketone 100 g, a surface modifier E Prepared.

(Example 6)
[Surface modification of base roll]
A base roll having the same configuration as in Example 1 was used, and surface modification with ultraviolet rays was performed instead of surface modification with surface modifier A. More specifically, the irradiation intensity: Surface modification by ultraviolet rays was performed under the conditions of 120 mW / cm ² , the distance between the light source of the ultraviolet irradiator and the surface of the elastic layer: 40 mm, and the irradiation time: 30 seconds. Thereby, the developing roll of Example 6 was obtained.

(Example 7)
A molding die of Example 7 was produced in the same manner as in Example 1 except that the molding time for molding the rubber elastic layer was changed to 38 minutes for the plating time. After using the shaping | molding die of Example 7 and obtaining a base roll like Example 1, surface modification of the produced base roll was performed using the surface modifier A like Example 1. FIG. Thereby, the developing roll of Example 7 was produced.

(Example 8)
As resin particles to be blended in the plating solution for forming the mold, acrylic particles <2> (manufactured by Negami Kogyo, Art Pearl GR800, average particle size 6 μm) are used instead of acrylic particles <1>, and acrylic particles <2 The developing roll of Example 8 was produced in the same manner as in Example 1 except that the blending amount of> was 12 g / L and the plating time was changed to 30 minutes.

Example 9
A developing roll of Example 9 was produced in the same manner as in Example 1 except that the plating time for forming the mold was changed to 60 minutes.

(Example 10)
Example 10 is similar to Example 1 except that the amount of acrylic particles <1> blended in the plating solution for forming the mold is changed to 15 g / L and the plating time is changed to 60 minutes. A developing roll was prepared.

(Reference example)
[Formation of coating layer F]
Using the base roll having the same configuration as in Example 1, the outer peripheral surface of the rubber elastic layer was coated with the following coating layer composition by a roll coating method, and then heat-treated at 170 ° C. for 60 minutes. A coating layer F having a thickness of 4 μm was formed. This produced the developing roll concerning a reference example.

[Preparation of coating layer composition]
10 parts by mass of carbon black (Denka Black HS-100, manufactured by Denki Kagaku Kogyo Co., Ltd.) is kneaded with 100 parts by mass of urethane resin (Nipporan 5199, manufactured by Nippon Polyurethane Co., Ltd.) using a ball mill, and then 400 parts by mass of MEK is added. Then, the coating layer composition of Reference Example was prepared by mixing and stirring.

(Comparative example)
<Preparation of developing roll>
[Production of base roll]
Comparative Example as in Example 1 except that a cylindrical mold substrate having an inner diameter of 16 mm was used as a mold for forming a rubber elastic layer without forming a plating film on the mold inner surface of the mold substrate. A base roll was prepared. On the surface of the base roll of the comparative example, no protrusion is formed by mold transfer of the mold.

[Formation of coating layer G]
The outer peripheral surface of the rubber elastic layer of the base roll of the comparative example was coated with the coating layer composition of the following comparative example by a roll coating method, and then heat-treated at 170 ° C. for 60 minutes, so that the thickness between the convex portions was 6 μm. The coating layer G was formed. Thereby, the developing roll which concerns on a comparative example was produced.

[Preparation of coating layer composition]
10 parts by mass of carbon black (Denka Black HS-100, manufactured by Denki Kagaku Kogyo Co., Ltd.) and acrylic particles <3> (manufactured by Negami Kogyo Co., Ltd., Art Pearl GR600) with respect to 100 parts by mass of urethane resin (Nipporan 5199, manufactured by Nippon Polyurethane Co., Ltd.) Then, after kneading 15 parts by mass of an average particle size of 10 μm using a ball mill, 400 parts by mass of MEK was added and mixed and stirred to prepare a coating layer composition of a comparative example.

For each developing roll, the height (h) of the convex portion of the rubber elastic layer, the diameter of the convex portion when the surface of the rubber elastic layer is observed (φ ₁ ), and the area ratio of the convex portion on the surface of the rubber elastic layer ( Ap ₁ ) and the thickness (t) of the coating layer in the portion between the protrusions were measured. In addition, each developer roll was evaluated for the adhesion of the toner particles to the layer forming blade. Furthermore, the fineness of the image was evaluated. The measurement method and evaluation method are shown below. The measurement results and evaluation results are shown in Table 1.

(Measurement method of height of convex part)
The heights of the three convex portions were measured at three locations in the central portion of the developing roll, and the average of the heights of the nine convex portions was taken as the height of the convex portion. More specifically, a cross section cut in the circumferential direction at the center portion of the roll was observed and measured by enlarging 1000 times with “Mx-1200E” manufactured by Nakaden.

(Measurement method of the diameter (φ ₁ ) of the convex part)
The diameter (φ ₁ ) of the convex portion was measured by magnifying an arbitrary position on the outer peripheral surface of the rubber elastic layer with “Mx-1200E” manufactured by Nakaden.

(Measurement method of area ratio of convex part (Ap ₁ ))
An arbitrary position on the outer peripheral surface of the rubber elastic layer was magnified by Maka 1200 made by Nakaden, and an area of 0.5 × 0.4 mm was captured at a resolution of 1280 × 1024 dpi. Next, the obtained image was subjected to monochrome conversion, and noise was removed with a smoothing filter in order to smooth the illuminance unevenness on the image. Subsequently, binarization processing was performed by a discriminant analysis method using NanoHunter NS2K-Pro / Lt manufactured by Nanosystem Corporation. Next, the binarized image is subjected to black-and-white reversal processing, and noise in the convex portions that are white in the image is removed (the black portion inside the white portion is filled), and then the area of this white portion is measured did. This white part is a convex part.

(Measurement method of coating layer thickness)
The film thickness at each of three points was measured at three locations in the central part of the developing roll, and the average value of the film thickness at a total of nine points was taken as the thickness of the coating layer. More specifically, a cross section cut in the circumferential direction at the center portion of the roll was observed and measured by enlarging 1000 times with “Mx-1200E” manufactured by Nakaden.

(Toner adhesion)
The developing roll was incorporated into a commercially available color laser printer (Oki Data Co., Ltd., “C5900”), and the image was printed with magenta in an environment of 28 ° C. × 80% RH 1000 sheets, 5000 sheets, 30000 sheets (each A4 size), and the degree of adhesion of the toner particles to the layer-forming blade after durability was determined. The case where the number of fixing points was 1 or less was evaluated as (◯), the case where the number of fixing sites was 2 to 4 (Δ), and the case where the number of fixing sites was 5 or more (×).

(Fineness of the image)
The developing roll was incorporated into a commercially available color laser printer (“C5900” manufactured by Oki Data Corporation), and a halftone image was printed (A4 size) under an environment of 28 ° C. × 80% RH. The region in the obtained image was divided into nine (3 × 3), and the Macbeth density of each region was measured. The density differences of the halftone images were evaluated by comparing the nine Macbeth densities and determining the difference between the highest value and the lowest value. A case where the variation in density was 0.02 or less was judged as “good”, a case where it was 0.03 to 0.04 was a little inferior “Δ”, and a case where 0.05 or more was judged as “bad”.

  Since the developing roll of the reference example has a coating layer formed on the outer periphery of the rubber elastic layer, the minute protrusions on the surface of the rubber elastic layer are buried and disappear, and there are portions where the protrusions are sparse on the roll surface. doing. For this reason, it is slightly inferior in the fineness of the image.

  The developing roll of the comparative example has a coating layer containing resin particles formed on the outer periphery of a rubber elastic layer having no uneven shape. As a result of durability evaluation, it is confirmed that the toner adheres to the layer forming blade after printing 5000 sheets. It was done.

  On the other hand, according to the example, as a result of durability evaluation, toner adhesion to the layer forming blade was not confirmed even after printing 30000 sheets. Also, the fineness of the image was good.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Developing roll for electrophotographic equipment 12 Shaft body 14 Rubber elastic layer 16 Convex part 20 Mold 22 Mold base 24 Plating film 24a Concave

Claims (1)

A developing roll for an electrophotographic apparatus comprising: a shaft body; and a rubber elastic layer formed on an outer periphery of the shaft body,
On the surface of the rubber elastic layer, a protrusion having a ratio of the height h to the diameter φ ₁ (h / φ ₁ ) of 0.5 or more when the position of the outer peripheral surface of the rubber elastic layer is observed by mold transfer Is formed,
The surface of the rubber elastic layer on which the many protrusions are formed is further subjected to surface modification that enhances toner releasability,
Any of the following a to d is used for the surface modification: a developing roll for an electrophotographic apparatus.
(A) Surface treatment A in which the following a1 component and a2 component are brought into contact with the surface of the rubber elastic layer
(A1) Trichloroisocyanuric acid (a2) Compound having an unsaturated carbon-carbon double bond and a functional group for imparting a function to the surface of the rubber elastic layer (b) On the surface of the rubber elastic layer, Surface treatment B in which the following b1 component and b2 component are contacted
(B1) a compound having two or more thiol groups (b2) a compound having a functional group capable of reacting with a thiol group and a functional group for imparting a function to the surface of the rubber elastic layer (c) the rubber elasticity Surface treatment C in which the following c1 component and c2 component are brought into contact with the surface of the layer
(C1) X ¹ (OX ² ) _n (where X ¹ is a hydrogen atom, alkali metal element, alkaline earth metal element or alkyl group, X ² is a halogen atom, and n is the same as the valence of X ¹⁾ And a compound having a —CONX ² — bond in the molecule (where X ² is a halogen atom), or two or more types (c2) BF ₃
(D) Surface treatment D with ultraviolet rays