JP5613081B2 - Developing roll for electrophotographic apparatus and method for producing mold - Google Patents

Description

  The present invention relates to a developing roll for electrophotographic equipment and a method for producing a mold suitable for molding a rubber elastic layer of a developing roll for electrophotographic equipment.

  The developing rolls of electrophotographic equipment such as copiers, printers and facsimiles that employ an electrophotographic method generally have an elastic layer made of a rubber material or the like formed on the outer peripheral surface of the shaft body, and various functions on the outer peripheral surface. Those having a surface layer formed for the purpose of imparting are known. The developing roll conveys toner to an image carrier such as a photosensitive drum, and the roll surface may be roughened in order to give the developing roll a toner conveying function.

  For example, in Patent Document 1, in a developing roll having a shaft body, an elastic layer formed on the outer peripheral surface of the shaft body, and an outermost layer formed on the outer periphery of the elastic layer, a large number of recesses are formed on the outer peripheral surface of the outermost layer. It is described that the surface is roughened by forming. In Patent Document 1, a large number of recesses are formed in an aluminum master roll by laser etching, and the corresponding protrusions are formed on the inner surface of the mold by electroforming, and are molded using this mold. It describes that a large number of recesses are formed on the outer peripheral surface of the elastic layer of the developing roll.

  In Patent Document 2, in a developing roll having a shaft, an elastic layer formed on the outer peripheral surface of the shaft, and a protective layer formed of a composition containing roughness forming particles on the outer periphery of the elastic layer, It is described that an uneven surface is formed by removing roughness forming particles buried in the vicinity of the outer peripheral surface of a protective layer.

JP 2006-309128 A JP 2008-116869 A

  However, in Patent Document 1, the recess of the aluminum master roll is formed by laser etching. For this reason, a recess having a large opening diameter and a shallow depth is formed on the surface of the developing roll. As a result, the toner particles accommodated in the recesses on the surface of the developing roll are easily pressed by the layer forming blade, and there is a possibility that stress is applied to the toner particles.

  On the other hand, the technique described in Patent Document 2 forms a recess in the protective layer. For this reason, this technique cannot be applied when forming a recessed part in the surface of an elastic layer.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developing roll for an electrophotographic apparatus that can obtain an appropriate toner conveyance amount and can further reduce stress on toner particles. Another object is to provide a method for manufacturing a mold that can manufacture such a developing roll for an electrophotographic apparatus.

In order to solve the above problems, an electrophotographic apparatus developing roll according to the present invention includes a shaft body and a rubber elastic layer formed on the outer periphery of the shaft body. The gist is that a large number of recesses satisfying the formulas (1) to (3) are formed.
1 ≦ φ ₁ ≦ 10 (1)
1 ≦ d (2)
30.0 ≦ Ap ₁ ≦ 78.5 (3)
However,
φ ₁ : Opening diameter of the recess (μm)
d: Depth of recess (μm)
Ap ₁ : Area ratio (%) of the recess when the photographed image of the rubber elastic layer surface is binarized using a discriminant analysis method

  At this time, it is desirable that the surface of the rubber elastic layer is subjected to surface modification for improving toner releasability. Alternatively, it is desirable that a surface layer for improving toner releasability is formed on the surface of the rubber elastic layer.

  On the other hand, the method for producing a mold according to the present invention is a method for producing a mold used for forming a rubber elastic layer of a developing roll for an electrophotographic apparatus, wherein dispersed particles are formed on the inner surface of a cylindrical mold base. A eutectoid plating step of forming a eutectoid plating layer in which a part of the dispersed particles are exposed on the surface by performing eutectoid plating using a plating solution containing, and plating on the entire surface of the eutectoid plating layer And a coating plating step for covering the exposed surface of the dispersed particles to form a large number of convex portions based on the dispersed particles on the inner surface of the mold.

  According to the developing roll for an electrophotographic apparatus according to the present invention, since a large number of recesses are formed on the surface of the elastic layer, toner particles can be accommodated in the recesses when the toner is transported. And since the opening diameter and depth of this recessed part are set to the specific magnitude | size, it can prevent that the toner particle accommodated in the recessed part is crushed by the layer formation blade. Thereby, the stress on the toner particles can be further reduced. In addition, since a large number of concave portions are distributed at a specific ratio on the surface of the elastic layer, an appropriate toner conveyance amount can be obtained and stress on the toner particles can be further reduced.

  According to the method for manufacturing a mold according to the present invention, a molding capable of forming an elastic layer of a developing roll having a characteristic surface structure capable of obtaining an appropriate toner conveyance amount and further reducing stress on the toner particles. A mold can be obtained.

1A is a schematic external view of a developing roll according to an embodiment of the present invention, and FIG. It is an enlarged view of the rubber elastic layer surface of the developing roll which concerns on one Embodiment of this invention, and is an enlarged view of the B point of FIG.1 (b). It is a schematic diagram showing the state which binarized the picked-up image of the rubber elastic layer surface of the image development roll concerning one Embodiment of this invention using the discriminant analysis method. It is a circumferential direction sectional view of the development roll concerning other embodiments of the present invention. It is an enlarged view of the rubber elastic layer surface of the image development roll which concerns on other embodiment of this invention, and is an enlarged view of the C point of FIG. It is a schematic diagram of the state which the rubber elastic layer and layer forming blade of the image development roll which concern on one Embodiment of this invention contacted. FIG. 3 is a schematic view showing a state in which toner particles are accommodated in a recess on the surface of a rubber elastic layer of a developing roll according to an embodiment of the present invention. 1 is a circumferential cross-sectional view of a mold suitable for molding a rubber elastic layer of a developing roll according to an embodiment of the present invention. It is a schematic diagram explaining an example of the manufacturing method of the shaping | molding die which concerns on this invention. It is the enlarged photograph (a) of the surface of the shaping | molding die of Example 2, and the enlarged photograph (b) of a cross section. It is an enlarged photograph (a) of the rubber elastic layer surface of Example 2, and its 3D photograph (b).

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

  FIG. 1 is a schematic view and a cross-sectional view of a developing roll 10 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the surface structure of the rubber elastic layer of the developing roll 10. FIG. 3 is a schematic diagram showing a binarized state of a captured image of the surface of the rubber elastic layer of the developing roll 10.

  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. From the viewpoint of enhancing toner releasability, the developing roll 10 may be subjected to surface modification that enhances toner releasability on the surface of the rubber elastic layer, or toner releasability on the surface of the rubber elastic layer. The surface layer which raises may be formed.

As shown in FIG. 2, a large number of recesses 14 a are formed on the surface of the rubber elastic layer 14. Thereby, the surface of the rubber elastic layer 14 is roughened. The concave portion 14a on the surface of the rubber elastic layer 14 has a relatively small opening diameter and a deep depth. That is, on the surface of the rubber elastic layer 14, a large number of recesses 14a having an opening diameter φ1 of ₁ to 10 μm and a depth d of 1 μm or more are formed. Moreover, the area ratio of the recessed part 14a which occupies for the surface of the rubber elastic layer 14 is 30.0-78.5%. That is, on the surface of the rubber elastic layer 14, a large number of recesses 14a that satisfy the following expressions (1) to (3) are formed.
1 ≦ φ ₁ ≦ 10 (1)
1 ≦ d (2)
30 ≦ Ap ₁ ≦ 78.5 (3)
However,
φ ₁ : Opening diameter of the recess (μm)
d: Depth of recess (μm)
Ap ₁ : Area ratio (%) of the recess when the photographed image of the rubber elastic layer surface is binarized using a discriminant analysis method

  The rubber elastic layer 14 can be formed by molding using, for example, a cylindrical mold. According to this method, the portion other than the concave portion 14a on the surface of the rubber elastic layer 14 is formed into a smooth curved surface with less irregularities because the smooth curved surface shape of the inner surface of the cylindrical mold is transferred. . It is preferable that the portion other than the concave portion 14a on the surface of the rubber elastic layer 14 is formed in a smooth curved surface with little unevenness.

The recesses 14a on the surface of the rubber elastic layer 14 are preferably independent of each other. That is, it is preferable that the concave portion 14a on the surface of the rubber elastic layer 14 is in a state where it does not overlap with the adjacent concave portion 14a (in a state where it is not continuous). Even when there are overlapping concave portions 14a between adjacent concave portions 14a on the surface of the rubber elastic layer 14, it is preferable to reduce the number thereof as much as possible. This is because if the recesses 14a overlap with each other, the opening diameter of the surface of the rubber elastic layer 14 increases, and the stress that the toner particles in the recess 14a receive from the layer forming blade may increase. As a method for preventing the concave portions 14a from being excessively overlapped, for example, by adjusting the number of the concave portions 14a so that the concave portions 14a are not excessively included, the area ratio Ap _{1 of the} concave portions 14a in the surface of the rubber elastic layer 14 is specified. The method of adjusting so that it may become in the range of this area ratio etc. is mentioned.

There is a possibility that the area ratio Ap ₁ recess 14a occupying the surface of the rubber elastic layer 14 and larger than the specific range, too overlap the recess 14a together. Thereby, the opening diameter of the surface of the rubber elastic layer 14 is increased, and there is a possibility that the stress that the toner particles in the recess 14a receive from the layer forming blade is increased. As a result, toner sticking is likely to occur. On the other hand, if the area ratio Ap ₁ recess 14a occupied in the surface of the rubber elastic layer 14 is less than the specified range, the area ratio of the portion other than the concave portion 14a is increased, the toner particles are non-recessed portion 14a that could not be received in the recess 14a There is a risk that the layer forming blade will be strongly stressed in this portion, and the toner adheres easily to the surface of the layer forming blade. Further, since the area ratio Ap ₁ recess 14a is small, the toner conveyance amount tends to decrease. The area ratio Ap ₁ of the recesses 14a occupying the surface of the rubber elastic layer 14 is preferably 70% or less, more preferably 60% or less, and even more preferably 50% or less.

Opening diameter phi ₁ is larger than the specific range of the recess 14a, there is a possibility that stress toner particles in the recess 14a receives from the layer forming blade becomes large. As a result, toner sticking easily occurs. On the other hand, when the opening diameter phi ₁ of recess 14a is smaller than the specified range, too small an amount to accommodate the toner particles in the recess 14a, the toner conveyance amount is decreased. As opening diameter (phi) ₁ of the recessed part 14a, More preferably, it exists in the range of 3-10 micrometers.

  If the depth d of the recess 14a is shallower than the specific range, the stress that the toner particles in the recess 14a receive from the layer forming blade may increase. As a result, toner sticking easily occurs. Further, when a surface layer is provided on the outer periphery of the rubber elastic layer 14, the recess 14a of the rubber elastic layer 14 is easily filled with the surface layer. As a result, the toner conveyance amount may be reduced. The depth d of the recess 14a is more preferably in the range of 2 to 10 μm.

The size of the opening diameter φ ₁ of the recess 14 a can be measured by observing the surface of the rubber elastic layer 14. Further, the depth d of the recess 14a can be measured by observing a circumferential cross section of the rubber elastic layer 14. For these observations, for example, a laser microscope (manufactured by Keyence Corporation, VK-9510 or the like), a microscope (manufactured by Nakaden, Mx-1200E or the like), or the like can be used.

When obtaining the area ratio Ap ₁ of the recesses 14a occupying the surface of the rubber elastic layer 14, the photographed image has 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 or more. It is good to use what was photographed. At this time, it is preferable that the size of one dot on the image is set to be 1/15 or less of the opening diameter φ ₁ of the recess 14a. The captured image may be converted into monochrome so that it can be easily binarized. Further, in order to smooth the illuminance unevenness on the image, it is preferable to remove noise with a smoothing filter. The binarization of the captured image may be performed using a discriminant analysis method on the image after monochrome conversion and noise removal. In order to calculate the area of the recess 14a and to make it easier to remove noise, the binarized image is subjected to black-and-white reversal processing to fill in the noise generated inside the white portion corresponding to the recess 14a. After removal, the area of the white portion should be measured. The area can be measured using commonly used image processing software. In FIG. 3, the schematic diagram showing the state which binarized the picked-up image of the rubber elastic layer 14 surface using the discriminant analysis method is shown.

  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, an operation of focusing on a portion of the surface of the rubber elastic layer 14 where the concave portion 14a does not exist is performed. However, in the microscope Mx-1200E, a three-dimensional depth composite image can be easily taken. It is possible to observe the surface of the rubber elastic layer 14 with clearer. The binarization process can be performed using, for example, NanoHunter NS2K-Pro / Lt manufactured by Nanosystem Corporation.

  Here, an example of a structure in which the surface layer 16 for enhancing the toner releasability is formed on the surface of the rubber elastic layer 14 is shown in FIGS. The surface layer 16 may impart various functions required for the surface of the developing roll to the surface of the roll in addition to the function of improving the toner releasability. As shown in FIG. 4, the developing roll 20 includes a shaft body 12, a rubber elastic layer 14 formed on the outer periphery of the shaft body 12, and a surface layer 16 formed on the outer periphery of the rubber elastic layer 14.

As shown in FIG. 5, a large number of recesses 14 a are formed on the surface of the rubber elastic layer 14. Thereby, the surface of the rubber elastic layer 14 is roughened. The area ratio Ap ₁ of the recess 14a occupying the surface of the rubber elastic layer 14 is as described above. A large number of recesses 14 a having a specific opening diameter φ ₁ and a depth d are formed on the surface of the rubber elastic layer 14. Opening diameter phi ₁ and the depth d of the recess 14a is as for above.

The thickness of the surface layer 16, depending on the relationship between the aperture diameter phi ₁ and the depth d of the recess 14a, is preferably 10μm or less. If the thickness of the surface layer 16 is too thick, the recess 14a of the rubber elastic layer 14 may be filled and the toner conveyance amount may be reduced. Further, since the roll surface is flattened, the stress that the toner particles receive from the layer forming blade may increase. The thickness of the surface layer 16 is more preferably 8 μm or less. On the other hand, the lower limit of the thickness of the surface layer 16 is preferably 2 μm or more from the viewpoint of sufficiently exerting the function as the functional layer. More preferably, it is 5 μm or more.

Here, examples of the surface modification that improves the toner releasability performed on the surface of the rubber elastic layer 14 include the following surface modifications 1) to 5). However, X ¹ is a hydrogen atom, an alkali metal element, an alkaline earth metal element or an alkyl group, X ₂ is a halogen atom, n represents the same integer as the valence of X ^1.

1) Surface modification performed by contacting trichloroisocyanuric acid 2) Surface modification performed by contacting a compound having two or more thiol groups 3) By contacting X ¹ (OX ² ) _n and BF ₃ Surface modification performed 4) Surface modification performed by contacting a compound having —CONX ₂ — bond in the molecule and BF ₃ 5) Surface modification performed by irradiation with ultraviolet rays

  The surface modification 1), the surface modification 3), and the surface modification 4) are performed when the rubber elastic layer 14 is formed of a polymer containing an organic component having an unsaturated carbon-carbon double bond. It can be suitably applied to. The surface modification of 2) can be suitably applied when the rubber elastic layer 14 is formed of a polymer containing an organic component having a functional group that reacts with a thiol group.

  In the polymer for surface modification of 2), functional groups that react with thiol groups include unsaturated carbon-carbon double bonds, halogen groups, epoxy groups, hydroxyl groups, isocyanate groups, methylol groups, carboxyl groups, carbonyl groups, and the like. Can be mentioned. In this respect, the surface modification of 2) has a wide application range.

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

  In addition, even if the polymer originally has no unsaturated carbon-carbon double bond, an unsaturated carbon-carbon double bond is introduced by copolymerization with a monomer component having an unsaturated carbon-carbon double bond. Polymer. Examples of such polymers 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.

  Examples of the polymer 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 the surface modification of 1) is performed, trichloroisocyanuric acid is added to the unsaturated carbon-carbon double bond on the surface of the rubber elastic layer 14. At this time, a chlorine atom derived from trichloroisocyanuric acid is also added. Chlorine atoms are present not only on the surface of the rubber elastic layer 14 but also on the inside, and the abundance of chlorine atoms increases from the inside toward the surface. These can be detected by, for example, X-ray photoelectron spectroscopy (XPS) or nuclear magnetic resonance (NMR).

  In the surface modification of 1), in addition to toner releasability, a compound capable of adding a new function to the surface of the rubber elastic layer 14 may be brought into contact with the surface of the rubber elastic layer 14 together with trichloroisocyanuric acid. Examples of such a compound include a compound having an unsaturated carbon-carbon double bond and a functional group for imparting a function to the surface of the rubber elastic layer 14 (hereinafter, also referred to as a specific functional group). be able to. In this case, a compound having an unsaturated carbon-carbon double bond and a specific functional group can be bonded (added) to the surface of the rubber elastic layer 14 via the isocyanuric acid skeleton of trichloroisocyanuric acid. Thereby, an organic group having a specific functional group is bonded to the surface of the rubber elastic layer 14 via the isocyanuric acid skeleton, and the surface of the rubber elastic layer 14 is subjected to surface modification.

  In the surface modification of 1), an example of the surface structure of the rubber elastic layer 14 obtained when using a compound having an unsaturated carbon-carbon double bond and a specific functional group together with trichloroisocyanuric acid is represented by the following formula 1 Shown in

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.

  Specific functional groups include 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, and heterocyclic rings. Groups, mesoionic groups, halogen groups, amino groups, imino groups, alkyl groups, sulfonic acid groups, hydroxy groups, acyl groups, formyl groups, carboxylic acid groups, urea groups, cyano groups and the like. Of these functional groups, only one type of functional group 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.

  When the specific functional group is, for example, a silicone group, the surface of the rubber elastic layer 14 can have a low friction property as a specific function as well as an excellent releasability with respect to an attached substance. When the specific functional group is, for example, a silicone group or a perfluoroalkyl group, the surface of the rubber elastic layer 14 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 14 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 14 can have antistatic properties that lower the electrical resistance of the surface as a specific function. Even when the specific functional group is a functional group other than these, the surface of the rubber elastic layer 14 can have a specific function based on each functional group as well as excellent releasability with respect to the attached matter.

  In the surface modification of 1), a solvent that dissolves trichloroisocyanuric acid or a compound having an unsaturated carbon-carbon double bond and a specific functional group can be used. Such solvents are not particularly limited, but ether solvents (THF, diethyl ether, dioxane, etc.), ester solvents (ethyl acetate, butyl acetate, etc.), ketone solvents (acetone, MEK, etc.) Amide 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. Further, in the surface modification of 1), other components can be used. Examples of other components include acids, bases, catalysts such as metal salts, and surfactants.

  When the surface modification of 2) is performed, a compound having two or more thiol groups is added to the surface of the rubber elastic layer 14 via a thiol group. This can be detected by, for example, X-ray photoelectron spectroscopy (XPS) or nuclear magnetic resonance (NMR).

  Examples of the compound having two or more thiol groups include a chain thiol compound having two or more thiol groups bonded to a chain structure and a cyclic thiol compound having two or more thiol groups bonded to a cyclic structure. be able to. 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 14 can be increased due to the effect of non-conjugated electrons, and the chargeability and discharge performance of the rubber elastic layer 14 can be improved.

  In the surface modification of 2), as in the case of the surface modification of 1), in addition to the toner releasability, the compound that can add a new function to the surface of the rubber elastic layer 14 has two or more thiol groups. You may make it contact the surface of the rubber elastic layer 14 with a compound. Examples of such a compound include a compound having a functional group capable of reacting with a thiol group and a functional group (specific functional group) for imparting a function to the surface of the rubber elastic layer 14.

  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 further imparting a specific function to the surface of the rubber elastic layer 14, and examples thereof include those similar to those shown in the surface modification of 1).

  When a compound having a functional group capable of reacting with a thiol group and a specific functional group is used, a compound having a functional group capable of reacting with a thiol group and a specific functional group via a compound having two or more thiol groups Can be bonded (added) to the surface of the rubber elastic layer 14. As a result, an organic group having a specific functional group is bonded to the surface of the rubber elastic layer 14 via a compound having two or more thiol groups, and the surface of the rubber elastic layer 14 is subjected to surface modification.

In the surface modification of 2), an example of the surface structure of the rubber elastic layer 14 obtained when a compound having a functional group capable of reacting with a thiol group and a specific functional group is used together with a compound having two or more thiol groups Trithiocyanuric acid as an example of a compound having two or more thiol groups, and an unsaturated carbon-carbon double bond and a specific function as examples of compounds having a functional group capable of reacting with a thiol group and a specific functional group A compound having a group is shown in the following formula 2. However, R ^{1 to} R ⁴ are the same as those shown in Formula 1.

  In the surface modification of 2), a solvent that dissolves a compound having two or more thiol groups, a compound having a functional group capable of reacting with the thiol group and a specific functional group, or the like can be used. Examples of such a solvent include the same solvents as those shown in the surface modification of 1). Further, in the surface modification of 2), other components can be used. Examples of other components include acids, bases, catalysts such as metal salts, and surfactants.

  When the surface modification of 3) or the surface modification of 4) is performed, the unsaturated carbon-carbon double bond of the rubber elastic layer 14 is halogenated, and the structure represented by the following formulas 3 to 4 is the structure of the rubber elastic layer 14. Formed on the surface portion. In addition, it can confirm that it has the structure shown to Formula 3-4 if the roll surface is analyzed by X-ray photoelectron spectroscopy (XPS), a nuclear magnetic resonance method (NMR), etc.

In the surface modification of 3), as the compound represented by X ¹ (OX ² ) _n , more specifically, for example, methyl hypochloride, ethyl hypochloride, tertiary butyl hypochloride, trifluoromethyl hypochloride Alkyl hypohalides such as alkyl hypochlorides such as chloride, methyl hypofluoride, ethyl hypofluoride, tertiary butyl hypofluoride, alkyl hypofluoride such as trifluoromethyl hypofluoride, hypochlorous acid, Examples thereof include hypochlorites such as lithium hypochlorite, sodium hypochlorite, magnesium hypochlorite, and potassium hypochlorite. These may be used alone or in combination of two or more.

In the surface modification of 4), as a compound having —CONX ² — bond in the molecule, more specifically, for example, N-chlorosuccinimide, N-chlorophthalimide, N-bromosuccinimide, N-bromophthalimide and the like Examples thereof include acid imide halogen compounds, isocyanuric halides such as trichloroisocyanuric acid and dichloroisocyanuric acid, and halogenated hydantoins such as dichlorodimethylhydantoin.

In the surface modification of 3) or the surface modification of 4), after contacting X ¹ (OX ² ) _n or BF ₃ , or contacting a compound having a —CONX ₂ — bond in the molecule or BF ₃ Then, it is preferable to wash away the surface of the rubber elastic layer 14 with a liquid containing water. Thereby, a hydroxyl group is easily introduced into the surface of the rubber elastic layer 14.

In the surface modification of 5), the ultraviolet irradiation conditions are appropriately determined according to the type of ultraviolet irradiation apparatus used. Generally, conditions of irradiation intensity: about ²⁰ to 150 mW / cm ² , distance between the ultraviolet light source and the elastic layer surface: about 20 to 80 mm, and irradiation time: about 5 to 360 seconds are employed. Ultraviolet irradiation can be performed in an inert gas such as nitrogen gas or argon gas, or in the air.

  By performing these surface modifications, the hardness of the surface of the rubber elastic layer 14 is increased, so that the toner releasability can be improved. Moreover, the barrier effect which suppresses that a component blooms from the rubber elastic layer 14 is also acquired by performing these surface modifications. In addition, in the surface modification of 1) to 4), the surface of the rubber elastic layer 14 is formed with covalent bonds of molecules and atoms that enhance toner releasability and other functions. Excellent. Also, the surface modification of 5) is excellent in the durability of the function of improving the toner releasability.

  As described above, the developing roll 10 having the above configuration includes an opening based on the concave portion 14a formed in the rubber elastic layer 14 on the roll surface. Therefore, the effects obtained by the developing roll 10 having such a surface structure will be described with reference to the drawings. The developing roll 20 is configured to further include a surface layer 16 on the outer periphery of the rubber elastic layer 14. However, the developing roll 10 is different from the developing roll 10 in that the roll surface includes an opening portion based on the recess 14 a formed in the rubber elastic layer 14. Since it has the same characteristics, the same effect as the developing roll 10 is exhibited.

  As shown in FIG. 6, when the developing roll 10 and the layer forming blade 22 come into contact with each other, the surface of the developing roll 10 is pressed against the layer forming blade 22. At this time, the portion that contacts the layer forming blade 22 is a portion other than the concave portion 14 a on the surface of the rubber elastic layer 14. Therefore, the surface of the layer forming blade 22 is in surface contact with a portion (such as a smooth surface) other than the recess 14a. Since the area of the roll surface in contact with the surface of the layer forming blade 22 is large, the uneven shape of the roll surface is not easily crushed. For this reason, it is possible to suppress an increase in the stress that the toner particles in the recess 14 a receive from the layer forming blade 22.

  Further, it is easier to smooth the portions other than the recesses 14a, while making the depth of the recesses 14a on the surface of the rubber elastic layer 14 uniform. For example, by using a cylindrical mold, it is possible to easily smooth the portions other than the recesses 14a. If the portion other than the concave portion 14a is smooth, the surface of the layer forming blade 22 can uniformly contact the roll surface. Thereby, since the pressure from the layer forming blade 22 is uniformly applied to the surface of the rubber elastic layer 14, a uniform toner layer can be formed on the roll surface, and a uniform image can be easily obtained.

  As shown in FIG. 7, when the toner particles 24 are conveyed, the toner particles 24 are accommodated in the recesses 14a on the roll surface. For this reason, the transport amount of the toner particles 24 does not increase excessively, and an appropriate toner transport amount can be obtained.

  Conventionally, as a configuration of the developing roll, a configuration having a shaft body, an elastic layer formed on the outer peripheral surface of the shaft body, and a protective layer formed of a composition containing roughness forming particles on the outer periphery of the elastic layer It has been known. In the case of such a configuration, a plurality of convex portions are formed on the roll surface by the roughness forming particles in the protective layer. In this case, the surface of the layer forming blade makes point contact with the convex portion of the roll surface. For this reason, the convex part of the roll surface is easily crushed due to stress concentration. If it does so, a layer formation blade will contact the toner particle accommodated in the clearance between a convex part easily. This tends to increase the stress on the toner particles.

  Further, since the convex portions on the roll surface are based on the roughness forming particles, the height of the convex portions on the roll surface is likely to vary due to the difference in particle diameter. That is, the height of the roll surface is likely to vary. For this reason, the layer forming blade is difficult to uniformly contact the roll surface. If it does so, it will become difficult to apply the pressure from a layer formation blade uniformly on the surface of a rubber elastic layer.

  Further, in such a conventional configuration, the toner particles are accommodated in the clearance between the convex portions. For this reason, the toner conveyance amount tends to increase.

  Next, a mold suitable as a mold used for forming the rubber elastic layer 14 of the developing roll 10 and a method for producing the mold according to the present invention (hereinafter sometimes referred to as the present production method) will be described. FIG. 8 is a circumferential cross-sectional view of a mold 30 suitable for molding the rubber elastic layer 14 of the developing roll 10 according to an embodiment of the present invention. FIG. 9 is a schematic diagram illustrating an example of a method for manufacturing the mold 30 according to the present invention.

  As shown in FIG. 8, the mold 30 includes a cylindrical mold base 32, and the mold inner surface of the mold base 32 is plated 34. Such a mold 30 can be manufactured by this manufacturing method.

  This manufacturing method includes a eutectoid plating step for forming a eutectoid plating layer on the inner surface of the cylindrical mold base 32 and a coating plating step for forming a coating plating layer on the entire surface of the eutectoid plating layer. ing. Through these steps, a large number of convex portions based on the dispersed particles are formed on the inner surface of the mold 30.

  In the eutectoid plating step, electroless plating is performed using a plating solution containing dispersed particles. Dispersed particles co-deposit with the plated metal by electroless plating. As a result, as shown in FIG. 9A, the eutectoid plating layer 36 containing the dispersed particles 36 a is formed on the inner surface of the mold base 32. In the eutectoid plating step, the plating metal is grown so that a part of the dispersed particles 36a (a part of the surface) is exposed on the surface. The dispersed particles 36 a are temporarily fixed to the inner surface of the mold base 32 by the plating metal of the eutectoid plating layer 36.

  In the coating plating step, electroless plating is performed using a plating solution that does not contain dispersed particles. As a result, as shown in FIG. 9B, a coating plating layer 38 is formed on the eutectoid plating layer 36. When the dispersed particles 36a are resin particles, the surface of the resin particles 36a can be electrolessly plated by adsorbing the electroless plating catalyst to the resin particles 36a prior to the coating plating step. When the coated plating layer 38 is formed, the dispersed particles 36 a are covered with the plating metal of the coated plated layer 38, so that the dispersed particles 36 a are securely fixed to the inner surface of the mold base 32. In the coating plating step, the projections based on the dispersed particles 36a are not buried by the plating metal.

  The thickness of the eutectoid plating layer 36 is related to the average particle size of the dispersed particles 36a, but is preferably in the range of 3 to 15 μm. If the thickness of the eutectoid plating layer 36 is less than 3 μm, the temporary fixation of the dispersed particles 36a tends to be insufficient. On the other hand, when the thickness of the eutectoid plating layer 36 exceeds 15 μm, the exposed area of the dispersed particles 36a tends to be small, and the formation of the convex portions on the inner surface of the mold tends to be insufficient. The thickness of the eutectoid plating layer 36 is more preferably in the range of 6 to 12 μm. In addition, the thickness of the eutectoid plating layer 36 is a thickness in a flat portion where the dispersed particles 36a do not exist.

  The thickness of the coating plating layer 38 is related to the average particle diameter of the dispersed particles 36a and the degree of exposure of the dispersed particles 36a, but is preferably in the range of 0.5 to 5 μm. When the thickness of the coating plating layer 38 is less than 0.5 μm, the dispersion particles 36 a are not sufficiently fixed. On the other hand, when the thickness of the coating plating layer 38 exceeds 5 μm, the dispersed particles 36a are buried and the formation of the convex portions based on the dispersed particles 36a tends to be insufficient. The thickness of the coating plating layer 38 is more preferably in the range of 1 to 3 μm. In addition, the thickness of the coating plating layer 38 is a thickness in a flat portion where the dispersed particles 36a do not exist.

  Examples of the dispersed particles 36a include acrylic particles, styrene particles, urethane particles, nylon particles, silicone particles, cellulose particles, and silica particles. As the dispersed particles 36a, a single type of particles may be used, or a plurality of types of 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 eutectoid plating layer 36.

  The average particle size of the dispersed particles 36a is preferably 15 μm or less in consideration of the average particle size of the toner particles. More preferably, it exists in the range of 1-12 micrometers, More preferably, it exists in the range of 3-10 micrometers. As the dispersed particles 36a, particles having different average particle diameters may be used in combination. The average particle size of the dispersed particles 36a can be measured with a Microtrac particle size distribution analyzer UPA-EX150 manufactured by Nikkiso Co., Ltd.

  The blending amount of the dispersed particles 36a in the plating solution is related to the average particle diameter of the dispersed particles 36a, but is in the range of 0.1 to 100 g / L in order to prevent the dispersed particles 36a from being too close to each other. It is preferable to be within. More preferably, it is in the range of 3 to 20 g / L. If the dispersed particles 36a are too close to each other, the concave portions 14a are excessively overlapped and are likely to be connected.

  The plating solution (plating solution for eutectoid plating) used in the eutectoid plating step includes metal ions, reducing agents, complexing agents, pH buffering agents, dispersed particles 36a, 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 dispersed particles 36a can be co-deposited with the plating metal at a high density. Further, when an amine compound is used, 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 dispersed particles 36a. 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 easy co-deposition of the dispersed particles 36a at a high density. As the complexing agent, it is particularly preferable to use glycine and citric acid in combination.

  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 dispersed particles 36a. Moreover, the amount of eutectoid on the eutectoid plating layer of the dispersed particles 36a can be increased by charging the dispersed particles 36a to a positive charge and adding it to the plating solution.

  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.

  The dispersed particles 36a can be subjected to etching treatment with an acid such as hydrochloric acid or sulfuric acid before being added to the plating solution for the purpose of improving the wettability to the plating solution. Furthermore, the degree of dispersion of the dispersed particles 36a can be further increased by sonicating the plating solution to which the dispersed particles 36a are added.

  The plating solution (plating solution for coating plating) used in the coating plating step includes metal ions, reducing agents, complexing agents, pH buffering agents, and the like. Moreover, it is preferable to mix | blend a fluororesin particle | grain with this plating solution for the purpose of improving mold release property, when the rubber elastic layer 14 using the shaping | molding die 30 is shape | molded. The fluororesin particles have an average particle size smaller than that of the dispersed particles 36a and are smaller than the toner particles. For this reason, the fluororesin particles do not appear as convex portions on the inner surface of the mold and do not form the concave portions 14 a for accommodating the toner particles in the rubber elastic layer 14. The average particle size of such fluororesin particles is preferably 0.5 μm or less. More preferably, it is 0.3 μm or less. Examples of the fluororesin particles include PTFE resin particles.

  As described above, a mold 30 suitable as a mold used for forming the rubber elastic layer 14 of the developing roll 10 can be manufactured. A large number of convex portions based on the dispersed particles 36 a are formed on the inner surface of the mold 30. By adjusting the average particle size of the dispersed particles 36a, the size of the diameter of the convex portion of the mold 30 can be adjusted. Moreover, the area ratio of the convex part which occupies for the type | mold inner surface of the shaping | molding die 30 can be adjusted by adjusting the compounding quantity to the plating solution of the dispersion particle 36a.

  By forming the rubber elastic layer 14 of the developing roll 10 using the mold 30 having a large number of convex portions on the inner surface of the mold thus obtained, the surface of the rubber elastic layer 14 corresponds to the convex portions. Many recesses 14a to be formed are formed (mold transfer). The surface of the rubber elastic layer 14 thus formed can be provided with a large number of recesses 14a having the characteristics described above.

  For the rubber elastic layer 14 of the developing roll 10, for example, the shaft body 12 is set in the hollow portion of the molding die 30 described above, and a rubber material is poured into the gap between the molding die 30 and the shaft body 12 to perform heat crosslinking. Then, it can be formed on the outer periphery of the shaft body 12 by removing from the mold 30. On the surface of the obtained rubber elastic layer 14, the surface modification described above is performed or a surface layer 16 is formed according to the necessity for improving the toner releasability. The surface modification method is as described above.

  The surface layer 16 can be formed, for example, by preparing a coating material for forming the surface layer 16 and applying the prepared coating material to the surface of the rubber elastic layer 14. Examples of the coating method include a roll coating method, a spray coating method, and a dipping method. After coating, the surface layer 16 can be formed by drying the paint and subjecting it to a heat crosslinking treatment as necessary.

  Next, the material and configuration of the developing roll 10 will be described. Further, the material of the mold 30 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.

  Although it does not specifically limit as a rubber material of the rubber elastic layer 14, Specifically, silicone rubber, urethane rubber, butadiene rubber, hydrin rubber, etc. can be illustrated. 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 thickness of the rubber elastic layer 14 is preferably in the range of 0.1 to 10 mm. More preferably, it exists in the range of 1-5 mm.

  The main material of the surface layer 16 is, for example, urethane resin, polyamide resin, acrylic resin, acrylic silicone resin, butyral resin (PVB), alkyd resin, polyester resin, fluororubber, fluororesin, mixture of fluororubber and fluororesin, silicone Resins, silicone-grafted acrylic polymers, acrylic-grafted silicone polymers, nitrile rubber, urethane rubber and the like can be mentioned. These may be used alone or in combination of two or more. Among these, urethane resin is preferable in terms of wear resistance. The material of the surface layer 16 may contain a conductive agent, a plasticizer, a leveling agent and the like in addition to the main material.

  The material of the mold base 32 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.

  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 eutectoid plating solution>
A dispersion of dispersed particles is prepared by dispersing 12 g / L of acrylic particles having an average particle size of 10 μm (Art Pearl GR600, manufactured by Negami Kogyo Co., Ltd.) in water with 0.1 g / L of a cationic surfactant (lauryltrimethylammonium chloride). did. Next, nickel sulfate hexahydrate 20 g / L, sodium hypophosphite monohydrate (reducing agent) 25 g / L, lactic acid (complexing agent) 27 g / L, propionic acid (complexing agent) 2.5 g / L A dispersion of dispersed particles was added to the basic plating solution consisting of L to prepare a eutectoid plating solution having a pH of 4.8.

<Preparation of coating plating solution>
10 g / L of PTFE fine particles having an average particle diameter of 0.2 μm were dispersed in water with 0.2 g / L of a cationic surfactant (lauryltrimethylammonium chloride) to prepare a mold release treatment dispersion. Next, nickel sulfate hexahydrate 20 g / L, sodium hypophosphite monohydrate (reducing agent) 25 g / L, lactic acid (complexing agent) 27 g / L, propionic acid (complexing agent) 2.5 g / L Into the basic plating solution made of L, a dispersion for mold release treatment was added to prepare a coating plating solution.

<Production of mold>
Electroless plating was performed on the inner surface of a cylindrical mold base having an inner diameter of 12 mm using a eutectoid plating solution under the conditions of a plating solution temperature of 90 ° C. and a plating time of 60 minutes (plating thickness: 11 μm). Next, the inner surface of the mold subjected to electroless plating was washed with water, and then immersed in an aminocarboxylic acid surfactant (Okuno Pharmaceutical Co., Ltd., “Condizer SP”) at 50 ° C. for 10 minutes to adjust the surface. It was. Then, it was immersed in tin-palladium colloid (Okuno Pharmaceutical Co., Ltd., “OPC-80 Catalyst”) at 25 ° C. for 10 minutes to perform adsorption treatment of the catalyst precursor. After washing with water, the catalyst was immersed in a 10% by mass hydrochloric acid aqueous solution at 25 ° C. for 10 minutes to activate the palladium catalyst. Next, after washing with water, electroless plating was performed using the coating plating solution under the conditions of a plating solution temperature of 90 ° C. and a plating time of 10 minutes (plating thickness 2 μm). As a result, the dispersed particles were fixed on the inner surface of the mold, and a convex shape was obtained on the inner surface of the cylindrical mold base. This produced the shaping | molding die.

<Preparation of rubber elastic layer composition>
Conductive silicone rubber (X-34-264A / B, manufactured by Shin-Etsu Chemical Co., Ltd., mixing mass ratio A / B = 30/70) is mixed with a static mixer, so that the C = C bond is surfaced. The rubber elastic layer composition containing the silicone rubber left in the above was prepared.

<Preparation of surface 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, a surface layer composition was prepared by mixing and stirring.

<Preparation of surface modifier>
5 parts by mass of trichloroisocyanuric acid (manufactured by Tokyo Kasei Kogyo 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, 20 parts by mass of ethyl acetate Were mixed to prepare a surface modifier.

<Preparation of developing roll>
A conductive shaft (φ6 mm, length 270 mm) was set coaxially in the mold, the rubber elastic layer composition was injected into the mold, heated at 190 ° C. for 30 minutes, cooled and demolded. Thereby, a rubber elastic layer having a thickness of 3 mm was formed on the outer periphery of the conductive shaft. A large number of concave portions corresponding to the large number of convex portions formed on the inner surface of the mold are formed on the outer peripheral surface of the rubber elastic layer by mold transfer. Next, the outer surface of the rubber elastic layer was coated with a surface layer composition by a roll coating method, and then heat treated at 170 ° C. for 60 minutes to form a surface layer having a thickness of 5 μm. As described above, the developing roll according to Example 1 was produced.

(Examples 2-3)
The addition amount of the acrylic particles and the addition amount of the surfactant added to the eutectoid plating solution are the amounts shown in Table 1, and the thickness of the surface layer is the same as that of Example 1, except that the thickness is shown in Table 1. The developing roll which concerns on Examples 2-3 was produced.

Example 4
As acrylic particles to be added to the eutectoid plating solution, acrylic particles having an average particle size of 6 μm (manufactured by Negami Kogyo Co., Ltd., Art Pearl GR800) are used. The amount of acrylic particles added is 12 g / L, and the amount of surfactant added is 0. Example 4 was carried out in the same manner as in Example 1, except that the eutectoid plating time was 30 minutes, the thickness of the eutectoid plating layer to be formed was 5.5 μm, and the thickness of the surface layer was 3 μm. The developing roll which concerns on was produced.

(Example 5)
As acrylic particles to be added to the eutectoid plating solution, acrylic particles having an average particle diameter of 2 μm (manufactured by Negami Kogyo Co., Ltd., Art Pearl J4PY) are used. The amount of acrylic particles added is 12 g / L, and the amount of surfactant added is 0. 0.5 g / L, the eutectoid plating time is 15 minutes, the thickness of the eutectoid plating layer to be formed is 2.3 μm, and the surface modification of the rubber elastic layer is performed at room temperature instead of the surface layer formation. In the same manner as in Example 1, a developing roll according to Example 5 was produced.

(Example 6)
A developing roll according to Example 6 was produced in the same manner as in Example 1 except that the surface modification of the rubber elastic layer was performed instead of forming the surface layer.

(Comparative Example 1)
<Preparation of transfer mold>
An aluminum cylinder having the same diameter as the outer diameter of the rubber elastic layer was prepared, and laser etching was performed on the outer peripheral surface of the aluminum cylinder to form a large number of concave portions in a distributed manner. The conditions for laser etching at this time are as follows: laser beam type: Nd-YAG laser, output: 50 W, aluminum cylinder rotated at output: 35 A, frequency: 5 kHz, irradiation speed: 1030 mm / sec. Laser was irradiated to the outer peripheral surface of the aluminum cylindrical body by 50 mm. In this way, an aluminum master roll was obtained, and a transfer mold was produced by electrocasting using the aluminum master roll.

<Preparation of developing roll>
A rubber elastic layer (thickness 3 mm, length 240 mm) was formed on the outer peripheral surface of the conductive shaft (φ6 mm, length 270 mm) by molding (190 ° C. × 30 minutes) using the transfer mold. As a result, a large number of concave portions were distributed and formed on the outer peripheral surface of the rubber elastic layer. Next, as in Example 5, the surface modification of the rubber elastic layer was performed. Thereby, a developing roll according to Comparative Example 1 was produced.

(Comparative Example 2)
A developing roll according to Comparative Example 2 was produced in the same manner as in Example 4 except that the addition amount of the acrylic particles was 6 g / L and the addition amount of the surfactant was 0.1 g / L.

(Comparative Example 3)
As acrylic particles to be added to the eutectoid plating solution, acrylic particles having an average particle diameter of 14 μm (manufactured by Negami Kogyo Co., Ltd., Art Pearl GR400) are used. The addition amount of the acrylic particles is 12 g / L, and the addition amount of the surfactant is 0. Comparative Example 3 in the same manner as in Example 1 except that the eutectoid plating time was 90 minutes, the thickness of the eutectoid plating layer to be formed was 16.5 μm, and the thickness of the surface layer was 8 μm. The developing roll which concerns on was produced.

(Comparative Example 4)
A developing roll according to Comparative Example 4 was produced in the same manner as in Example 1 except that the thickness of the surface layer was 12 μm.

(Comparative Example 5)
The developing roll according to Comparative Example 5 was prepared in the same manner as in Example 1 except that the addition amount of acrylic particles was 36 g / L, the addition amount of the surfactant was 0.6 g / L, and the thickness of the surface layer was 3 μm. Produced.

(Comparative Example 6)
The same procedure as in Example 4 was performed except that the addition amount of the acrylic particles was 9 g / L, the addition amount of the surfactant was 0.15 g / L, and the surface modification of the rubber elastic layer was performed instead of the formation of the surface layer. A developing roll according to Comparative Example 6 was produced.

With respect to the rubber elastic layer of each developing roll, the opening diameter φ _{1 of} the recess, the depth d of the recess, and the area ratio Ap _{1 of the} recess in the rubber elastic layer surface were measured. Moreover, about the developing roll of the structure which has a surface layer, the thickness of the surface layer was further measured. The measuring method is as follows. Further, the amount of toner transported and the toner fixing property were examined using each of the produced developing rolls. The measuring method is as follows.

(Opening diameter of the recess φ ₁ )
Any position on the outer circumference surface of the rubber elastic layer, by enlarging observed in Nakaden made "Mx-1200E", was measured opening diameter phi ₁ of the concave portion of the rubber elastic layer.

(Depth of recess d)
The depth d of the concave portion of the rubber elastic layer was measured by magnifying and observing an arbitrary position of the cross section cut in the circumferential direction at the center of the roll with “Mx-1200E” manufactured by Nakaden.

(Recessed area ratio 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 inversion processing to remove noise in the concave portions that are white in the image (the black portion inside the white portion is filled), and then the area of this white portion is measured did. This white portion is a recess.

(Surface 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 surface 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 transport amount)
Each developing roll is incorporated into a commercially available color laser printer (“C5900” manufactured by Oki Data Corporation), and a solid white image is printed with a cyan cartridge in an environment of 23 ° C. × 53% RH, and 6.3 cm above the developing roll at that time. ^The amount of toner in the range of ² was measured, and the toner conveyance amount per unit area was calculated.

(Toner adhesion)
Each developing roll is incorporated into a commercially available color laser printer ("C5900" manufactured by Oki Data Corporation), and images are printed out with cyan paper (A4 size) in cyan under an environment of 28 ° C x 80% RH. The degree of adhesion of the toner particles to the layer forming blade 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 (×).

  Further, in order to specifically show the surface structure and the cross-sectional structure of the mold of the example, as a representative example of the mold manufactured in Example 2, using “SEMEDX Type N” manufactured by Hitachi, “GX51” manufactured by Olympus, An enlarged photo of the surface and an enlarged photo of the cross section were taken. This is shown in FIGS. 10 (a) and 10 (b). Moreover, in order to show concretely the surface structure of the rubber elastic layer of the image development roll of an Example, about the image development roll produced in Example 2 as the representative example, a laser microscope (made by Keyence Corporation, VK-9510) was used. An enlarged photograph of the surface of the rubber elastic layer and a 3D photograph thereof were taken. This is shown in FIGS. 11 (a) and 11 (b).

  10 (a) and 10 (b), it can be confirmed that a large number of convex portions based on the dispersed particles are formed on the inner surface of the mold. Further, it can be confirmed that the surface of the dispersed particles is covered with the coating plating layer. And according to Fig.11 (a) (b), it can confirm that the several recessed part is formed in the surface of a rubber elastic layer.

  From Table 1, it can be confirmed that according to the embodiment, the toner conveyance amount is appropriate, and the occurrence of toner sticking to the layer forming blade can be suppressed while maintaining such an appropriate toner conveyance amount. It was.

  On the other hand, Comparative Example 1 is a developing roll in which many concave portions are formed on the surface of the rubber elastic layer by a conventional method, and the opening diameter of the concave portions is large and the depth is shallow. For this reason, the stress on the toner particles from the layer forming blade is increased, and the amount of toner adhering to the layer forming blade is increased.

  In Comparative Examples 2 and 6, since the area ratio of the recesses on the surface of the rubber elastic layer is small, the area ratio of the parts other than the recesses is increased, and the amount of toner adhering to the layer forming blade is increased. In Comparative Example 3, since the opening diameter of the concave portion is too large, the amount of toner sticking to the layer forming blade is increased. In Comparative Example 4, since the surface layer is too thick, the concave portion on the surface of the rubber elastic layer is filled too much, and the amount of toner adhered to the layer forming blade is increased. Further, the toner conveyance amount is reduced. In Comparative Example 5, since the area ratio of the recesses on the surface of the rubber elastic layer is large, the recesses are excessively connected, and the opening diameter of the roll surface is too large. For this reason, the amount of toner adhered to the layer forming blade is increased.

  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, 20 Developing roll 12 for electrophotographic apparatus Shaft body 14 Rubber elastic layer 14a Recess 16 Surface layer 30 Mold 32 Mold base 34 Plating 36 Eutectoid plating layer 36a Dispersed particles 38 Coating plating layer

Claims (4)

A shaft body, and a rubber elastic layer formed on the outer periphery of the shaft body,
The rubber elastic layer is a mold of a molding die base material in which a eutectoid plating layer containing dispersed particles and a coating plating layer formed on the entire surface of the eutectoid plated layer and covering the exposed surface of the dispersed particles are cylindrical. Formed on the inner surface of the mold using a molding die having a large number of protrusions based on the dispersed particles,
On the surface of the rubber elastic layer, a large number of recesses satisfying the following formulas (1) to (3) are formed , and on the surface of the rubber elastic layer, a surface layer for improving toner releasability is 10 μm or less in thickness. A developing roll for an electrophotographic apparatus, wherein
1 ≦ φ1 ≦ 10 (1)
1 ≦ d (2)
30.0 ≦ Ap1 ≦ 78.5 (3)
However,
φ1: Opening diameter of recess (μm)
d: Depth of recess (μm)
Ap1: Area ratio (%) of the recess when the photographed image of the rubber elastic layer surface is binarized using a discriminant analysis method A shaft body, and a rubber elastic layer formed on the outer periphery of the shaft body,
The rubber elastic layer is a mold of a molding die base material in which a eutectoid plating layer containing dispersed particles and a coating plating layer formed on the entire surface of the eutectoid plated layer and covering the exposed surface of the dispersed particles are cylindrical. Formed on the inner surface of the mold using a molding die having a large number of protrusions based on the dispersed particles,
The surface of the rubber elastic layer has a large number of recesses that satisfy the following formulas (1) to (3) , and the surface of the rubber elastic layer is subjected to surface modification that enhances toner releasability. A developing roll for electrophotographic equipment.
1 ≦ φ1 ≦ 10 (1)
1 ≦ d (2)
30.0 ≦ Ap1 ≦ 78.5 (3)
However,
φ1: Opening diameter of recess (μm)
d: Depth of recess (μm)
Ap1: Area ratio (%) of the recess when the photographed image of the rubber elastic layer surface is binarized using a discriminant analysis method A method for producing a mold used for forming a rubber elastic layer of a developing roll for an electrophotographic apparatus according to claim 1 or 2 ,
A eutectoid plating layer in which a part of the dispersed particles is exposed on the surface by performing eutectoid plating using a plating solution containing dispersed particles on the inner surface of a cylindrical mold base. Plating process,
A plating process for covering the exposed surface of the dispersed particles by plating the entire surface of the eutectoid plating layer,
A method for producing a mold, wherein a large number of convex portions based on the dispersed particles are formed on the inner surface of the mold. It is a manufacturing method of the developing roll for electrophotographic equipment according to claim 1 or 2,
The rubber elastic layer is a mold of a molding die base material in which a eutectoid plating layer containing dispersed particles and a coating plating layer that is formed on the entire surface of the eutectoid plated layer and covers the exposed surface of the dispersed particles A method for producing a developing roll for an electrophotographic apparatus, comprising forming a molding die formed on an inner surface and having a plurality of convex portions based on the dispersed particles on the inner surface of the mold.