JP2022065922A - Charging member with coating layer - Google Patents

Abstract

To provide stable charging evenness over a long period of time.SOLUTION: A charging member 10 comprises a conductive support 1, and a conductive body 5 mounted on the conductive support. The conductive body includes an elastic layer located on the conductive support, a resin layer 3 located on the elastic layer, and a coating layer 4 containing a polysiloxane compound that is located on the resin layer to form an outermost surface of the conductive body. The coating layer has protuberances along the outermost surface of the conductive body, which are substantially dome-shaped and have an average diameter of approximately 4 to 16 μm. The outermost surface of the conductive body has a skewness (Rsk) of approximately 1.0 to 3.2 and a ten-point average roughness (Rzjis) of approximately 11.5 to 32.0 μm.SELECTED DRAWING: Figure 1

Description

The image forming apparatus is a photoconductor, a charging device, an exposure device that forms an electrostatic latent image on the photoconductor, a developing device that applies toner to the electrostatic latent image to develop it, and a transfer device that transfers a toner image on the photoconductor. It is equipped with a transfer device that transfers to the material. The charging device is provided with a charging member that charges the photoconductor.

It is a schematic cross-sectional view of the example of a charged member. FIG. 3 is a schematic cross-sectional view showing an enlarged example of the charging member of FIG. 1. FIG. 3 is a schematic cross-sectional view showing an enlarged example of the charging member of FIG. 1. It is a schematic cross-sectional view which shows the coating layer portion of the charging member of FIG. 1 further enlarged. It is a top view photograph of the coating layer of Example 1. FIG.

Hereinafter, an example of the charging member will be described with reference to the drawings as necessary. In the description based on the drawings, the same elements or similar elements having the same functions are designated by the same reference numerals, and duplicate description will be omitted. Further, the dimensional ratio of each element is not limited to the ratio shown in the figure. Further, in the present specification, the value represented by "about" indicates the range including the value and the vicinity of the value. Therefore, the value represented by "about" may be, for example, the value itself with "about" deleted. Further, in the present specification, the numerical range indicated by using "-" indicates a range including the numerical values before and after "-" as the minimum value and the maximum value, respectively.

<Charging member and image forming device>
The charging member includes a conductive support and a conductive main body provided on the conductive support. The conductive main body has an elastic layer provided on the conductive support, a resin layer provided on the elastic layer, and a coating layer provided on the resin layer so as to form the outermost surface of the conductive main body. And prepare. Hereinafter, the details of the charging member will be described by taking the charging roller 10 shown in FIG. 1 as an example.

The charging roller (charging member) 10 includes a conductive main body 5 and a conductive support 1 that serves as a rotation axis of the conductive main body 5. The conductive main body 5 has a roller shape that rotates about the rotation axis L of the support 1. The conductive main body 5 is rotationally symmetric with respect to the rotation axis L and rotates about the rotation axis L.

The conductive main body 5 has a conductive elastic layer (conductive elastic layer) 2 in contact with the outer peripheral surface of the conductive support 1 and a conductive resin layer (conductive resin layer) 3 in contact with the outer peripheral surface of the elastic layer 2. It includes a conductive base 6 and an insulating coating layer (insulating coating layer) 4 in contact with the outer peripheral surface of the resin layer 3. The resin layer 3 may be provided around the elastic layer 2 via another layer. For example, an intermediate layer such as a resistance adjusting layer for enhancing withstand voltage resistance (leakage resistance) may be interposed between the elastic layer 2 and the resin layer 3. Further, the coating layer 4 may be provided around the resin layer 3 via another layer. However, since the orientation state of the polysiloxane compound (for example, a polysiloxane compound having a silicone structure or the like) in the coating layer 4 described later changes depending on the layer in contact with the coating layer 4, the physical state of the outermost surface (state of unevenness) is changed. ), Chemical properties (surface free energy, etc.) change. When the coating layer 4 is formed so as to be in direct contact with the outer peripheral surface of the resin layer 3, contamination of the surface of the conductive main body 5 due to contact with the photoconductor (for example, contamination by an external additive) is likely to be suppressed.

[Conductive support]
The conductive support 1 is not particularly limited as long as it is made of a conductive metal. The conductive support 1 may be, for example, a hollow metal body (pipe-shaped (circular tubular)) or a medium substance (rod-shaped) made of iron, copper, aluminum, nickel, stainless steel or the like. The outer peripheral surface of the conductive support 1 may be plated, if necessary, for the purpose of rust prevention and scratch resistance to the extent that the conductivity is not impaired. Further, the outer peripheral surface of the conductive support 1 may be coated with an adhesive, a primer or the like, if necessary, in order to enhance the adhesiveness with the elastic layer 2. At that time, in order to ensure sufficient conductivity, these adhesives, primers and the like may be made conductive as necessary.

The conductive support 1 may have, for example, a columnar shape having a length of about 250 to 360 mm. The portion of the conductive support 1 covered by the elastic layer 2 is formed, for example, in a columnar or cylindrical shape extending along the rotation axis L direction of the conductive support 1 (extending direction of the conductive support 1). Moreover, the diameter (outer diameter) may be constant (straight cylindrical shape or circular tubular shape) in the L direction of the rotation axis. The diameter of the portion of the conductive support 1 covered by the elastic layer 2 may be, for example, about 8 mm or more, and may be about 10 mm or less.

The portion of the conductive support 1 that is not covered by the elastic layer 2, that is, both ends of the conductive support 1, are supported by support members (not shown). The diameter of the portion of the conductive support 1 not covered by the elastic layer 2 may be smaller than the diameter of the portion covered by the elastic layer 2, for example. The conductive support 1 rotates about the rotation axis (cylindrical center line) L of the conductive support 1 in a state of being supported by the support member.

The conductive support 1 is urged toward the photoconductor side so that the surface of the coating layer 4 comes into contact with the surface of the photoconductor. That is, in order to press the surface of the coating layer 4 against the surface of the photoconductor, a load is applied to both ends of the conductive support 1 toward the photoconductor side. From the viewpoint of appropriately adhering the charging roller 10 to the rotating photoconductor, the load applied to one end of the conductive support 1 may be, for example, about 450 g or more, and about 750 g or less. May be.

[Elastic layer]
The elastic layer 2 is not particularly limited as long as it has appropriate elasticity in order to ensure uniform adhesion to the photoconductor. The elastic layer 2 is, for example, natural rubber; ethylene-propylene-diene rubber (EPDM), styrene-butadiene rubber (SBR), silicone rubber, polyurethane-based elastomer, epichlorohydrin rubber, isoprene rubber (IR), butadiene rubber (BR), acrylonitrile. -Synthetic rubber such as butadiene rubber (NBR), hydrogenated NBR (H-NBR), chloroprene rubber (CR); synthetic resin such as polyamide resin, polyurethane resin, silicone resin; etc.; good. In other words, the elastic layer 2 may be composed of an elastic body containing these base polymers or a crosslinked body thereof. These may be used individually by 1 type or in combination of 2 or more type. From the viewpoint of uniform adhesion to the photoconductor, the base polymer may contain a rubber component (natural rubber or synthetic rubber) as a main component. More specifically, the base polymer may contain a rubber component in an amount of about 50% by mass or more, or may contain an amount of about 80% by mass or more.

Well-known additives such as a conductive agent, a vulcanizing agent, a vulcanization accelerator, a lubricant, and an auxiliary agent are appropriately blended in the base polymer for the purpose of imparting desired properties to the elastic layer 2. You may. However, from the viewpoint of forming stable resistance, the elastic layer 2 (elastic body) may contain epichlorohydrin rubber and a crosslinked body thereof as a main component. More specifically, the elastic layer 2 may contain epichlorohydrin rubber and a crosslinked product thereof in an amount of about 50% by mass or more, or may contain about 80% by mass or more.

Examples of the conductive agent include carbon black, graphite, potassium titanate, iron oxide, conductive titanium oxide (c-TiO ₂ ), conductive zinc oxide (c-ZnO), conductive tin oxide (c-SnO ₂ ), and the like. A quaternary ammonium salt or the like may be used. As the vulcanizing agent, sulfur or the like may be used. As the vulcanization accelerator, tetramethylthiuram disulfide (CZ) or the like may be used. As the lubricant, stearic acid or the like may be used. As the auxiliary agent, zinc oxide (ZnO) or the like may be used.

The thickness of the elastic layer 2 may be, for example, about 1.25 mm or more and may be about 3.00 mm or less in order to exhibit appropriate elasticity.

[Resin layer]
The resin layer 3 is a layer containing a resin and harder than the elastic layer (for example, having a high elastic modulus measured according to JIS K7162). By providing the resin layer 3 on the elastic layer 2, bleeding of the plasticizer or the like from the elastic layer 2 to the surface of the conductive main body 5 can be suppressed.

The resin layer 3 may contain, for example, a matrix material and particles dispersed in the material. Since the resin layer 3 contains particles, the resin layer 3 has an uneven shape on the surface. The particles may be one kind or two or more kinds. For example, the resin layer 3 may be a layer containing the matrix material 30 and the first particles 31 dispersed in the same material as shown in FIG. 2, and the resin layer 3 may be a layer containing the matrix material 31 as shown in FIG. It may be a layer containing the material 30, the first particles 31 dispersed in the same material, and the second particles 32 of different types from the first particles 31. Here, different types include different materials, shapes, and the like. For example, even if the material of the first particle 31 and the material of the second particle 32 are the same, if the shapes are different from each other, the types of the first particle 31 and the second particle 32 are different. ..

Matrix materials include, for example, base polymers. Examples of the base polymer include fluororesin, polyamide resin, acrylic resin, nylon resin, polyurethane resin, silicone resin, butyral resin, styrene-ethylene / butylene-olefin copolymer (SEBC), and olefin-ethylene / butylene-olefin. A polymer such as a polymer (CEBC) may be used. These may be used alone or in combination of two or more. For example, the base polymer is at least one selected from the group consisting of fluororesins, acrylic resins, nylon resins, polyurethane resins and silicone resins from the viewpoint of ease of handling, the degree of freedom in material design, and the like. It may be at least one selected from the group consisting of nylon resin and polyurethane resin.

The content of the base polymer in the resin layer may be, for example, about 30% by mass or more and may be about 90% by mass or less based on the total amount of the resin layer.

The matrix material further contains, for example, various conductive agents (conductive carbon, graphite, copper, aluminum, nickel, iron powder, conductive tin oxide, conductive titanium oxide, ionic conductive agent, etc.), charge control agents, and the like. You may be.

The particles (eg, first particle 31 and second particle 32) may be insulating particles. The particles may be resin particles or inorganic particles. The particles are not particularly limited as long as they can form irregularities on the surface of the resin layer so as to sufficiently secure a discharge point. Examples of the material of the resin particles include urethane resin, polyamide resin, fluororesin, nylon resin, acrylic resin, urea resin and the like. Examples of the material of the inorganic particles include silica and alumina. These may be used alone or in combination of two or more. The particles are selected from the group consisting of nylon resin particles, acrylic resin particles, and polyamide resin particles from the viewpoints of compatibility with the matrix material 30, dispersion retention after addition of the particles, stability after coating (pot life), and the like. It may be at least one kind, and may be at least one kind selected from the group consisting of nylon resin particles and acrylic resin particles.

The shape of the particles (for example, the first particle 31 and the second particle 32) is not particularly limited as long as it can form irregularities on the surface of the resin layer 3, and is a true sphere or an elliptical sphere. , It may be irregular or the like.

The content of the particles (for example, the total amount of the first particles 31 and the second particles 32) may be, for example, about 5 to 50% by mass based on the total mass of the resin layer. When the content of the particles is about 5% by mass or more, the charging performance tends to be more satisfied, and when the content of the particles is about 50% by mass or less, the particles settle when they are made into a paint. It tends to be easier to control and less likely to degrade paint stability. From the same viewpoint, the content of the particles may be about 10 to 40% by mass and may be about 20 to 30% by mass based on the total mass of the resin layer. The content of particles contained in the resin layer is, for example, the weight change (TG), differential heat (DTA), calorific value (DSC) and volatile components generated by sampling the resin layer from a charged member and heating it. It can be quantified by measuring the mass (MS) of (TG-DTA-MS, DSC (thermal analysis)).

When the particles contain the first particle 31 and the second particle 32, the ratio of the content of the first particle 31 to the second particle 32 is, for example, from the viewpoint that excellent charging performance is more likely to be exhibited. , About 5: 1 to 1: 5, and may be about 3: 1 to 1: 3.

In the resin layer 3, the layer thickness A (“A” in FIGS. 2 and 3) of the particle-free portion (for example, the portion without the first particle 31 and the second particle 32) (the portion with only the matrix material 30). The portion) may be, for example, about 1.0 μm or more, about 2.0 μm or more, or about 3.0 μm or more, and may be about 7.0 μm or less, about 6.0 μm or less, or about 5.0 μm or less. When the resin layer 3 contains particles, the layer thickness A is the thickness at the midpoint between the nearest particles. When the layer thickness A is about 1.0 μm or more, it becomes easy to continuously hold the resin particles to be added without dropping them for a long period of time. When the layer thickness A is about 7.0 μm or less, it becomes easy to maintain good charging performance. The layer thickness A is measured by cutting out a cross section of the conductive main body 5 with a sharp cutting tool and observing it with an optical microscope or an electron microscope.

When the particles contain only the first particles 31, the average (average particle diameter B) of the particle diameters (“B” portion in FIG. 2) of the first particles 31 is from the viewpoint of suppressing charge unevenness, which is an initial image defect. Therefore, it may be about 5.0 to 50.0 μm. From the same viewpoint, the average particle diameter B of the first particles 31 may be about 15.0 to 30.0 μm. In the present specification, the average particle size of particles can be derived by arbitrarily extracting 100 particles from a population of a plurality of particles by SEM observation and taking the average value of those particle sizes. .. However, if the particle shape is not a true sphere and the particle diameter is not uniformly determined, such as an ellipsoidal sphere (a sphere with an ellipsoidal cross section) or an irregular shape, the simple average value of the longest diameter and the shortest diameter is used for the particle. The particle size of.

When the resin layer 3 contains the first particles 31 and the second particles 32, the average (average particle diameter B) of the particle diameters (“B” portion in FIG. 3) of the first particles 31 is From the viewpoint of suppressing charge unevenness, which is an initial image defect, it may be about 15.0 to 40.0 μm, and the average particle diameter (“C” portion in FIG. 3) of the second particle 32 (average particle diameter C). ) May be about 15.0 μm or more and may be about 40.0 μm or less from the viewpoint of suppressing charge unevenness, which is an initial image defect. From the viewpoint of suppressing uneven charging, the average particle diameter B of the first particles 31 may be larger than the average particle diameter C of the second particles 32. For example, the average particle diameter B of the first particle 31 may be larger than the average particle diameter C of the second particle 32 by about 10 μm or more.

The ratio (B / A) of the average particle diameter B of the first particles 31 to the layer thickness A of the resin layer 3 may be about 5.0 to 30.0. When the B / A is about 5.0 or more, it becomes easy to sufficiently secure the charge uniformity, and when the B / A is about 30.0 or less, the coating liquid for forming the conductive resin layer is applied. It becomes easy to improve the workability, and it becomes easy to suppress the falling off of particles. From the same viewpoint, the B / A may be about 7.5 to 20.0 and may be about 8.0 to 12.5.

The interparticle distance of the particles (ie, the interparticle distance in all particles including the first particle 31 and optionally the second particle 32) may be about 50-400 μm. When the inter-particle distance is about 50 μm or more, it becomes easy to suppress the roughness and the particle shedding on the surface of the conductive resin layer, and when the inter-particle distance is about 400 μm or less, it becomes easy to suppress the particle shedding. From the same viewpoint, the interparticle distance may be about 75 to 300 μm and may be about 100 to 250 μm. The distance between particles can be measured according to JIS B0601-1994.

The resin layer 3 may be, for example, a layer formed by impregnating the surface of an initially existing elastic layer with a solution containing an isocyanate compound and then curing the resin layer 3. In this case, the cured portion on the surface side of the elastic layer that initially existed becomes the resin layer 3, and the other cured portion becomes the elastic layer 2. In this method, the elastic layer may be molded by polishing to form irregularities on the surface of the elastic layer (the surface of the resin layer 3 system-formed after impregnation with the solution). Thereby, the skewness (Rsk) and the ten-point average roughness (Rzjis) of the outermost surface of the conductive main body 5 can be adjusted within the range described later.

The isocyanate compounds include, for example, 2,6-toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPDI), 1,5-naphthalenedi isocyanate (NDI) and 3,3-dimethyl. It may be diphenyl-4,4'-diisocyanate (TODI), and multimers and modified products thereof.

The solvent of the solution containing the isocyanate compound is not particularly limited as long as it is an organic solvent capable of dissolving the isocyanate compound. The organic solvent may be, for example, ethyl acetate or the like. The solution may further contain at least one polymer selected from carbon black, an acrylic fluorine-based polymer, and an acrylic silicone-based polymer, a conductivity-imparting agent, and the like.

The resin layer formed by impregnating the elastic layer with a solution containing an isocyanate compound and then curing it may contain, for example, an elastic body constituting the elastic layer 2 and a resin derived from the isocyanate compound.

The elastic body may be formed by using a base polymer containing acrylonitrile-butadiene rubber (NBR) or epichlorohydrin rubber as a main component from the viewpoint of good binding property to the resin derived from the isocyanate compound. More specifically, the base polymer may contain 50% by mass or more of acrylonitrile-butadiene rubber (NBR) or epichlorohydrin rubber, or may contain 80% by mass or more.

The resin derived from the isocyanate compound may be, for example, a resin having a urea bond, a urethane bond, or the like (urea resin, urethane resin, etc.). The resin derived from the isocyanate compound may be bonded to the base polymer and / or the crosslinked body in the elastic body by a urethane bond or the like.

When the resin layer 3 is formed by the method of impregnating the solution containing the isocyanate compound, the thickness of the resin layer 3 may be, for example, 1.0 μm or more, 10.0 μm or more, or 20.0 μm or more, and is 250. It may be 0.0 μm or less, 200.0 μm or less, or 150.0 μm or less.

[Coating layer]
The coating layer 4 contains a polysiloxane compound. By providing the surface of the coating layer 4 containing the polysiloxane compound on the resin layer 3 so as to be the outermost surface S of the conductive main body 5, the surface of the conductive main body 5 is contaminated by contact with the photoconductor (for example). Contamination by external additives) is suppressed. For example, when the photoconductor is miniaturized and the rotation speed of the charging roller 10 increases, or when the image forming apparatus does not have a cleaning charge roller (CCR) for removing an external additive adhering to the charging roller 10, it is charged. Contamination by the external additive of the roller 10 is likely to occur, but since the charging roller 10 is provided with the coating layer 4, contamination by the external additive is unlikely to occur even in the above case. Here, the "polysiloxane compound" means a compound having a plurality of Si—O—Si bonds (siloxane bonds) in the molecular structure. Three or four oxygen atoms may be bonded to Si constituting the Si—O—Si bond.

The polysiloxane compound has, for example, a Si—O—Zr bond in its molecular structure. The Si—O—Zr bond is a bond formed between the zirconium chelate compound and the hydrolyzable silane compound, for example, when the hydrolyzable silane compound is polymerized (self-condensed) in the presence of the zirconium chelate compound. Is. The Si constituting the Si—O—Zr bond can be the same as the Si constituting the Si—O—Si bond. Three or four oxygen atoms may be bonded to Si constituting the Si—O—Zr bond.

The polysiloxane compound may have a crosslinked structure derived from an epoxy group from the viewpoint of excellent surface hardness. More specifically, the polysiloxane compound may have a structural unit represented by the following formula (1) or (2).

In the formula (1), R ¹ to R ³ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a carboxyl group or an amino group, and X is a single bond or a divalent organic substance. A group is indicated, * indicates a bond to Si, and n indicates 0 or 1. Si may be Si constituting a Si—O—Zr bond, or may be Si constituting a Si—O—Si bond.

In formula (2), R ⁴ to R ⁵ independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a carboxyl group or an amino group, and R ⁶ to R ⁷ are independent of each other. It represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxyl group having 1 to 4 carbon atoms, and m represents an integer of 4 to 12 carbon atoms. X and * are synonymous with X and * in the formula (1).

The divalent organic group of X may be, for example, a divalent hydrocarbon group having 1 to 16 carbon atoms. A part of the carbon atom of the hydrocarbon group may be replaced with an oxygen atom. The hydrocarbon group may be linear or branched chain, and may be saturated or unsaturated. More specifically, the divalent organic group may be a group represented by the following formula (3) or formula (4).

In the formula (3), R ⁸ to R ⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and l represents an integer of 1 to 8. In formula (4), R ¹⁰ to R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and p and q each independently represent an integer of 1 to 8. The * in the formula (3) and the formula (4) is the same as the * in the formula (1) or the formula (2).

The structural unit represented by the above formula (1) may be a structural unit represented by the following formula (5) or formula (6).

In the formulas (5) and (6), n and * are the same as n and * in the formula (1). L in the formula (5) is the same as l in the formula (3), and p and q in the formula (6) are the same as p and q in the formula (4).

The structural unit represented by the above formula (2) may be a structural unit represented by the following formula (7) or (8).

The * in the formula (7) and the formula (8) is the same as the * in the formula (2). L in the formula (7) is the same as l in the formula (3), and p and q in the formula (8) are the same as p and q in the formula (4).

The polysiloxane compound further lowers the coefficient of friction of the surface of the conductive body 5 (the surface of the coating layer 4) and further suppresses contamination of the surface of the conductive body 5 due to contact with the photoconductor (for example, contamination by an external additive). From this point of view, it may have a structure represented by the following formula (9).

In formula (9), R ¹⁴ to R ¹⁸ each independently represent an alkyl group having 1 to 4 carbon atoms, r represents an integer of 10 to 100, and Y represents a divalent organic group. * In equation (9) is synonymous with * in equation (1).

Y in formula (9) may have an oxazolidone ring in the main chain. More specifically, Y may be a group represented by the following formula (10) or (11).

In the formula (10), R ¹⁹ to R ²¹ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a carboxyl group or an amino group. In the formula (11), R ²² to R ²³ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a carboxyl group or an amino group, and R ²⁴ to R ²⁵ are independent of each other. It represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxyl group having 1 to 4 carbon atoms, and s represents an integer of 4 to 12 carbon atoms. In formulas (10) and (11), A and B each independently represent a single bond or a divalent organic group. The details of the divalent organic group are the same as the details of the divalent organic group of X in the above formula (1). The * in the formula (10) and the formula (11) is the same as the * in the formula (9).

The coating layer 4 has substantially dome-shaped protrusions 4a, as shown in FIGS. 2-4. A large number of protrusions 4a are formed along the outermost surface of the conductive main body 5, and exist in a random dot shape, for example. Here, the "substantially dome shape" includes not only a spherical crown shape but also a shape having no uniform radius of curvature.

The protrusion 4a is substantially circular in a plan view, and its average diameter is about 4 to 16 μm. The average diameter is about 8 μm or more or about 12 μm from the viewpoint of further suppressing contamination of the surface of the conductive main body 5 due to contact with the photoconductor (for example, contamination by an external additive) while suppressing charging unevenness which is an initial image defect. It may be the above. The average diameter may be about 13 μm or less or about 10 μm or less from the viewpoint of further suppressing contamination of the surface of the conductive main body 5 due to contact with the photoconductor (for example, contamination by an external additive).

The average diameter of the protrusion 4a is an average value of the diameter of the protrusion 4a (“R” portion in FIG. 4) confirmed when the protrusion 4a is observed on a plane. Specifically, using KEYENCE VK-X121, the coating layer 4 is observed in a range of 107 μm × 143 μm from above, the diameter of the protrusions in the observation range is measured, and the average value thereof is obtained. At this time, if the diameter is less than 4 μm, it is not regarded as a protrusion and is not included in the measurement target. The same operation is performed at 6 points, the diameters (average values) of the protrusions obtained for each place are averaged, and the obtained value is taken as the average diameter of the protrusions. When the shape of the protrusion in the plan view is not a perfect circle, the average value of the longest diameter and the shortest diameter is taken as the diameter of the protrusion. For example, when the protrusion is elliptical in a plan view, the average value of the longest diameter and the shortest diameter of the ellipse is taken as the diameter of the protrusion.

The number of protrusions 4a per unit area is, for example, about 8.5 to 34 pieces / mm ² . When the number of protrusions 4a is within the above range, contamination of the surface of the conductive main body 5 due to contact with the photoconductor (for example, contamination by an external additive) can be further suppressed while suppressing charge unevenness which is an initial image defect. can. The number of protrusions 4a per unit area can be obtained in the same manner as in the measurement of the average diameter of the protrusions 4a.

The protrusions 4a may be formed on the entire surface (entire surface) of the coating layer 4, or may be formed on a part of the coating layer 4. From the viewpoint that contamination of the surface of the conductive main body 5 due to contact with the photoconductor (for example, contamination by an external additive) can be further suppressed, the region (for example, the number of projections 4a) in which the projections 4a are formed in the coating layer 4 is The ratio of about 8.5 to 34 / mm ² ) may be 95% or more of the total area of the coating layer 4.

In the coating layer 4, the layer thickness D (“D” portion in FIGS. 2 to 4) of the portion without the protrusion 4a may be, for example, about 30 nm or more, about 50 nm or more, or about 70 nm or more, and may be about 500 nm or less. , About 400 nm or less or about 300 nm or less.

The surface free energy γ ^Total (surface free energy on the outermost surface of the conductive body 5) of the coating layer 4 is a viewpoint of further suppressing contamination of the surface of the conductive body 5 due to contact with the photoconductor (for example, contamination by an external additive). Therefore, it may be about 35.0 mJ / m ² or less, about 25.0 mJ / m ² or less, or about 20.0 mJ / m ² or less. The surface free energy γ ^Total of the coating layer 4 is measured by the method described in Examples.

The surface free energy is the sum of the dispersion component (γ _S ^d ), the ^dipole component (γ _Sp ), and the hydrogen bond component ( _γ ^Sh ). From the viewpoint of further suppressing contamination of the surface of the conductive main body 5 due to contact with the photoconductor (for example, contamination by an external additive), in addition to the surface free energy of the coating layer 4 being in the above range, a dipole component (γ). The sum of ^Sp ) and the hydrogen bond component (γ _S ^h ) _may be about 12.0 mJ / m ² or less, about 8.0 mJ / m ² or less, or about 5.0 mJ / m ² or less.

Due to the resin layer 3 and the coating layer 4 as described above, the outermost surface of the conductive main body 5 has irregularities (for example, irregularities derived from the resin layer 3 and fine irregularities derived from the coating layer 4).

The skewness (Rsk) of the outermost surface of the conductive main body 5 is about 1.0 or more, and is about 1.2, from the viewpoint of exhibiting the effect of suppressing contamination of the surface of the conductive main body 5 by the protrusions 4a of the coating layer 4. As mentioned above, it may be about 1.4 or more, about 1.6 or more, about 1.8 or more, or about 2.0 or more. The skewness (Rsk) of the outermost surface of the conductive main body 5 is about 3.2 or less, about 3.0 or less, about 2.8 or less, about 2.6 or less, and about 2 from the viewpoint of suppressing uneven charging. It may be 0.4 or less or about 2.2 or less. Skewness (Rsk) represents the cube root average of Z (x) at a reference length made non-dimensional by the cube of the root mean square height (Zq).

The ten-point average roughness (Rzjis) of the outermost surface of the conductive main body 5 is 11.5 μm or more, 15.0 μm or more, 18.0 μm or more, 20.0 μm or more, 22. It may be 0 μm or more, 22.5 μm or more, or 23.0 μm or more. The ten-point average roughness (Rzjis) of the outermost surface of the conductive main body 5 is 32.0 μm or less, 30.0 μm or less, and 29.0 μm from the viewpoint of suppressing rotational unevenness (peripheral velocity deviation) of the charging roller 10. Hereinafter, it may be 28.0 μm or less, 27.5 μm or less, 27.0 μm or less, 26.5 μm or less, or 26.0 μm or less.

The skewness (Rsk) and the ten-point average roughness (Rzjis) are measured according to JIS B0601-2001 using a surface roughness measuring instrument SE-3400 manufactured by Kosaka Laboratory Co., Ltd. The skewness (Rsk) and the ten-point average roughness (Rzjis), as well as the other surface textures of the conductive body, are the size, shape, amount of particles contained in the resin layer 3, the number of protrusions 4a of the coating layer 4, and the number of protrusions 4a of the coating layer 4. It can be adjusted by changing the size, the layer thickness of the coating layer 4, and the like.

The conductive main body 5 may have a surface curved with respect to the rotation axis L. That is, the surface of the coating layer 4 may be curved with respect to the rotation axis L. The shortest distance (corresponding to 1/2 of the outer diameter of the conductive body 5) from the rotation axis L to the surface of the conductive body 5 (the surface of the coating layer 4) changes along the rotation axis L and rotates. It is maximum at the center point of the conductive main body 5 on the axis L (center point in the longitudinal direction of the conductive main body 5), and becomes smaller toward both ends of the conductive main body 5.

The crown amount can be used as an index for expressing the roller shape of the conductive main body 5. The crown amount of the conductive main body 5 is defined as follows.
Crown amount = d2- (d1 + d3) / 2
In the formula, d1 represents the outer diameter of the conductive main body 5 at a position 30 mm away from one end in the longitudinal direction (rubber length) of the conductive main body 5 toward the center point, and d2 is the longitudinal direction of the conductive main body 5. Represents the outer diameter of the conductive main body 5 at the center point of (rubber length), and d3 is the conductive main body 5 at a position 30 mm away from the other end of the longitudinal direction (rubber length) of the conductive main body 5 toward the center point. Represents the outer diameter of.

The crown amount of the conductive main body 5 is 50 μm or more and 60 μm from the viewpoint of achieving stable charging uniformity for a long period of time and maintaining the graininess of the image quality while appropriately adhering the charging roller 10 to the photoconductor. It may be more than or equal to 70 μm or more, and may be 130 μm or less, 120 μm or less, or 110 μm or less.

The charging member described above is provided as a charging means for charging the photoconductor in the image forming apparatus. More specifically, the charging member uniformly charges the surface of the photoconductor, which is an image carrier. That is, an example of the image forming apparatus includes a photoconductor and a charging member that charges the photoconductor.

In the image forming apparatus, for example, only a DC voltage may be applied to the charging member. At that time, the bias voltage applied during the image output may be −1000 to -1500V.

<Manufacturing method of charged member>
Hereinafter, the details of the manufacturing method of the charging member will be described by taking the manufacturing method of the charging roller 10 as an example.

The method for manufacturing the charging roller 10 is to prepare a conductive base 6 provided on the conductive support 1, prepare a coating liquid containing a composition containing a hydrolyzable silane compound, and prepare a conductive base. It comprises spray-coating the coating liquid on the surface of No. 6 and curing the composition to form the coating layer 4 on the conductive base 6. In this production method, a coating liquid containing the composition containing the hydrolyzable silane compound is spray-coated to form droplets (a film containing the droplets) on the surface of the conductive base, and the composition is formed. The protrusion 4a is formed by curing. The protrusion 4a has a shape derived from the droplet, and for example, the droplet and the protrusion 4a have substantially the same shape.

The conductive base 6 can be manufactured, for example, as follows. That is, first, a material for the elastic layer and a coating liquid for the resin layer are prepared. The material for the elastic layer can be prepared by kneading the material for the elastic layer 2 with a kneader such as a kneader. Further, the coating liquid for the resin layer can be prepared by kneading the material for the resin layer 3 using a kneader such as a roll, adding an organic solvent to the mixture, mixing and stirring. Next, the material for the elastic layer is filled in the injection molding die in which the core metal to be the conductive support 1 is set, and heat-crosslinking is performed under predetermined conditions. Then, by demolding, an elastic layer is formed along the outer peripheral surface of the conductive support 1 to manufacture a base roll. Then, the coating liquid for the resin layer is applied to the outer peripheral surface of the base roll to form the resin layer 3. In this way, the conductive base 6 including the elastic layer 2 formed on the outer peripheral surface of the conductive support 1 and the resin layer 3 formed on the outer peripheral surface of the elastic layer 2 can be manufactured.

The method for forming the elastic layer is not limited to the injection molding method, and a casting molding method or a method combining press molding and polishing may be adopted. Further, the coating method of the coating liquid for the resin layer is not particularly limited, and a conventionally known dipping method, roll coating method, or the like may be adopted.

The coating liquid may contain, for example, a composition containing a hydrolyzable silane compound which is a curable component (curable composition), and a solvent for dissolving or dispersing the components in the composition. Here, the curable component means a component incorporated into the structure of the polysiloxane compound produced when the coating liquid is cured. Therefore, the acid generator described later is not included in the curable component.

The hydrolyzable silane compound has a hydrolyzable silyl group represented by the following formula (12).

In formula (12), R ³¹ to R ³³ each independently represent a hydrocarbon group. The hydrocarbon group is, for example, an alkyl group having 1 to 4 carbon atoms. As the hydrolyzable silane compound, one type may be used alone, or a plurality of types may be used in combination.

The content of the hydrolyzable silane compound is 84.0 mol% or more, 88.0 mol% or more, or 90.0 mol% or more with respect to the total amount of the curable component from the viewpoint that excellent condensation efficiency can be easily obtained. good. The content of the hydrolyzable silane compound is 98.0 mol% or less, 97.0 mol% or less, or 96.0 mol% or less with respect to the total amount of the curable component from the viewpoint that excellent condensation efficiency can be easily obtained. good.

The composition may contain a zirconium chelate compound as a curable component. The zirconium chelate compound has a zirconium atom (Zr) which is a central metal and 1 to 4 chelate ligands (polydentate ligands) coordinated to the zirconium atom. The zirconium chelate compound promotes the polymerization (self-condensation) reaction of the hydrolyzable silane compound and contributes to the formation of a coating layer having a low surface free energy.

The chelate ligand may be, for example, a bidentate or tridentate ligand. The coordination atom of the chelate ligand may be, for example, an oxygen atom. More specifically, the chelate ligand may be, for example, an acetylacetonate group or an alkylacetacetate group. The alkyl of the alkylacetate group may be, for example, an alkyl having 1 to 10 carbon atoms.

The zirconium chelate compound may have a monodentate ligand. The monodentate ligand may be, for example, an alkoxy group. The alkoxy group may have, for example, 1 to 10 carbon atoms.

The zirconium chelate compound may be, for example, zirconium tributoxymonoacetylacetonate, zirconium dibutoxybis (acetylacetonate), zirconium dibutoxybis (ethylacetoacetate) or the like. As the zirconium chelate compound, one type may be used alone, or a plurality of types may be used in combination.

The content of the zirconium chelate compound may be 2.0 mol% or more, 3.0 mol% or more, or 4.0 mol% or more with respect to the total amount of the curable component from the viewpoint of shortening the reaction time. The content of the zirconium chelate compound may be 10.0 mol% or less, 8.0 mol% or less, or 6.0 mol% or less with respect to the total amount of the curable component from the viewpoint of the condensation rate.

The composition may contain a hydrolyzable silane compound having an epoxy group as a curable component. That is, at least a part of the hydrolyzable silane compound may be a hydrolyzable silane compound having an epoxy group. According to the hydrolyzable silane compound having an epoxy group, photocationic polymerization and thermosetting can be used in combination. The hydrolyzable silane compound having an epoxy group has, for example, a structure represented by the following formula (13) or (14) from the viewpoint that polymerization inhibition by oxygen is less likely to occur and from the viewpoint of being more excellent in surface curability. It's okay.

In the formula (13), R ¹ to R ³ and X are synonymous with R ¹ to R ³ and X in the formula (1). In formula (14), ^R4 to ^R7 , m and X are synonymous with ^R4 to ^R7 , m and X in formula (2). Q in the formula (13) and the formula (14) represents a hydrolyzable silyl group represented by the above formula (12).

Hydrolytic silane compounds having an epoxy group include, for example, (3-glycidoxypropyl) trimethoxysilane, (3-glycidoxypropyl) triethoxysilane, and 2- (3,4-epoxycyclohexyl) ethyltrimethoxy. It may be silane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, or the like. As the hydrolyzable silane compound having an epoxy group, one type may be used alone, or a plurality of types may be used in combination.

The content of the hydrolyzable silane compound having an epoxy group is 80.0 mol% with respect to the total amount of the curable component from the viewpoint of being able to further suppress the polymerization inhibition by oxygen and from the viewpoint of being more excellent in surface curability. As mentioned above, it may be 85.0 mol% or more or 90.0 mol% or more. The content of the hydrolyzable silane compound having an epoxy group is 97.5 mol% or less, 96.0 mol% or less, based on the total amount of the curable component, from the viewpoint of small curing shrinkage and good adhesion to the surface resin. It may be less than or equal to 95.0 mol% or less.

The composition containing the hydrolyzable silane compound having an epoxy group may further contain an acid generator. The acid generator may be a photoacid generator or a thermoacid generator. As the acid generator, one type may be used alone, or a plurality of types may be used in combination.

The photoacid generator can be activated by light having a wavelength of 365 to 405 nm by a UV-LED light source from the viewpoint of suppressing damage to the substrate due to heat from the light source and oxidative deterioration of the coating layer. It may be an agent. The photoacid generator may be, for example, a triarylsulfonium salt-based photoacid generator or the like.

The thermal acid generator may be a thermal acid generator that can be activated at a low temperature (for example, 250 ° C. or lower) from the viewpoint of suppressing damage to the substrate due to heat and oxidative deterioration of the coating layer. The thermal acid generator may be, for example, quaternary ammonium trifluoromethanesulfonic acid.

The content of the acid generator is 0.01 part by mass or more, 0.03 with respect to 100 parts by mass of the compound having an epoxy group (for example, a hydrolyzable silane compound having an epoxy group) from the viewpoint of improving the condensation rate. It may be by mass or more or 0.05 parts by mass or more. The content of the acid generator is 1.00 parts by mass or less with respect to 100 parts by mass of the compound having an epoxy group (for example, a hydrolyzable silane compound having an epoxy group) from the viewpoint of shortening the synthesis time. It may be 0.08 part by mass or less or 0.07 part by mass or less.

From the viewpoint of reducing the friction coefficient of the surface of the coating layer 4, the composition is a one-ended modified silicone compound having a structure represented by the following formula (16) as a curable component (silicon having a reactive group at one end). A compound) and a hydrolyzable silane compound having a functional group (hereinafter, also referred to as “binding functional group”) capable of reacting with the reactive group of the silicone compound to form a bond may be contained.

In formula (16), U represents a reactive group. R ¹⁴ to R ¹⁸ and r are synonymous with R ¹⁴ to R ¹⁸ and r in the formula (9), and A is synonymous with A in the formulas (10) and (11).

A silicone compound having excellent compatibility with other components in the coating liquid (for example, hydrolyzable silane having an epoxy group) by reacting the one-ended modified silicone compound with the hydrolyzable silane compound having a binding functional group. Is generated. As a result, the occurrence of phase separation in the coating layer 4 can be suppressed, and the coefficient of friction can be reduced over the entire surface of the coating layer 4.

The reactive group may be, for example, an epoxy group. More specifically, the reactive group may be a group represented by the following formula (17) or (18).

In the formula (17), R ¹⁹ to R ²¹ are synonymous with R ¹⁹ to R ²¹ in the formula (10). In the formula (18), R ²² to R ²⁵ and s are synonymous with R ²² to R ²⁵ and s in the formula (11).

The functional group equivalent (reactive group equivalent) of the one-ended modified silicone compound may be, for example, 1000 to 5000 g / mol.

The viscosity of the one-ended modified silicone compound at 25 ° C. may be, for example, 10 to 120 mm ² / s.

As the one-ended modified silicone compound, one type may be used alone, or a plurality of types may be used in combination.

The content of the one-ended modified silicone compound may be 0.1 mol% or more, 0.2 mol% or more, or 0.3 mol% or more with respect to the total amount of the curable component from the viewpoint of further reducing the friction coefficient. The content of the one-ended modified silicone compound may be 1.0 mol% or less, 0.9 mol% or less, or 0.8 mol% or less with respect to the total amount of the curable component from the viewpoint of suppressing phase separation.

The hydrolyzable silane compound having a binding functional group may have, for example, a structure represented by the following formula (19).

In the formula (19), L represents a binding functional group, and Q represents a hydrolyzable silyl group represented by the above formula (12). B is synonymous with B in equations (10) and (11).

The binding functional group represented by L may be, for example, a functional group (amino group, isocyanate group, etc.) capable of reacting with an epoxy group to form a bond, and further reduces the friction coefficient on the surface of the coating layer 4. From the viewpoint, it may be an isocyanate group.

The hydrolyzable silane compound having a binding functional group may be, for example, 3-isocyanatepropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, or the like. As the hydrolyzable silane compound having a binding functional group, one type may be used alone, or a plurality of types may be used in combination.

The content of the hydrolyzable silane compound having a binding functional group is 1.0 mol% or more, 1.5 mol% or more, or 2.0 mol% or more with respect to the total amount of the curable component from the viewpoint of suppressing phase separation. It may be there. The content of the hydrolyzable silane compound having a binding functional group is 5.0 mol% or less, 4.5 mol% or less, or 4 with respect to the total amount of the curable component from the viewpoint of further reducing the friction coefficient. It may be 0.0 mol% or less.

The composition may further contain a reaction product of a one-ended modified silicone compound and a hydrolyzable silane compound having a binding functional group. This reaction product may be synthesized in advance before the preparation of the coating liquid, or may be produced in the coating liquid. When the composition contains the above reaction product, it is assumed that the one-ended modified silicone compound and the hydrolyzable silane compound having a binding functional group are blended, respectively, and the one-ended modified silicone compound and the water having a binding functional group are added. The content of the degradable silane compound is calculated.

The solvent may include, for example, water. The solvent may further contain an alcohol solvent. That is, the solvent may be a mixed solvent of water and an alcohol solvent. In this case, the content of water in the solvent may be 10.0% by mass or more and 60.0% by mass or less based on the total mass of the solvent. As the alcohol solvent, methanol, ethanol, isopropyl alcohol or the like may be used.

The content of the solvent may be adjusted, for example, from the viewpoint of the viscosity of the coating liquid. The content of the solvent may be, for example, 95.0 to 99.9% by mass based on the total mass of the coating liquid.

The coating liquid is applied by spray application (application by the spray coating method). The spray application may be performed using, for example, an air brush.

In spray application, the size of the droplet can be adjusted by adjusting the injection amount of the coating liquid per unit time, the size of the injection port, the injection time to a predetermined place, and the like. For example, when using an airbrush, the gap between the needle and the injection port is adjusted by adjusting the position of the needle with the needle adjustment dial, and the amount of coating liquid (injection amount) to be injected per unit time is adjusted. adjust. Thereby, the protrusion 4a having a desired average diameter can be formed.

After the coating liquid is applied and before the composition is cured, the solvent in the formed coating may be removed by drying or the like. Drying may be performed at 130 to 220 ° C.

The curing method of the composition is not particularly limited. When the composition contains an acid generator, a suitable curing means (heating, light irradiation, etc.) may be adopted depending on the type of the acid generator. Heating and light irradiation may be used in combination as the curing means. When a photoacid generator is used, the composition is formed by irradiating light with a wavelength of 365 to 405 nm with a UV-LED light source from the viewpoint of suppressing damage to the base due to heat generated from the light source and oxidative deterioration of the coating layer. May be cured. The UV-LED light source is, for example, a UV-LED light source manufactured by Hamamatsu Photonics Co., Ltd., a UV-LED light source manufactured by HOYA Co., Ltd., a UV-LED light source manufactured by Iwasaki Electric Co., Ltd., and a UV-LED light source manufactured by Ushio Electric Co., Ltd. It may be a UV-LED light source, a UV-LED light source manufactured by Heleus Co., Ltd., a UV-LED light source manufactured by Aitec System Co., Ltd., a UV-LED light source manufactured by Microsphere Co., Ltd., or the like. When a thermal acid generator is used, the composition may be cured by heating at 250 ° C. or lower from the viewpoint of suppressing damage to the base due to heat and oxidative deterioration of the coating layer.

Hereinafter, the charging member will be described in more detail by way of examples, but the charging member is not limited to the embodiment.

<Preparation of coating liquid>
KBM-403 (trade name, manufactured by Shin-Etsu Chemical Industry Co., Ltd., (3-glycidoxypropyl) trimethoxysilane), which is a hydrolyzable silane compound having an epoxy group, and MCR-E11, which is a one-ended modified silicone compound. KBE-9007N (trade name, Shin-Etsu Chemical Industry Co., Ltd.), which is a hydrolyzable silane compound having an isocyanate group and a viscosity of 10 to 15 mm ² / s (25 ° C.) and a functional group equivalent of 1000 g / mol (trade name, manufactured by Gelest). AKZ947 (trade name, manufactured by Gelest, a solution of zirconium dibutoxybis (acetylacetonate), solid content 25 mass%), which is a zirconium chelate compound, and a solvent (3-isocyanoxide propyltriethoxysilane) and a solvent (manufactured by Gelest Co., Ltd.). Water and ethanol) were mixed, stirred at room temperature, and then heated and refluxed for 24 hours to obtain a condensate of hydrolyzable silane having a silicone skeleton. By adding this condensate to a mixed solvent of 2-butanol / ethanol, a condensate-containing alcohol solution having a solid content of 1.0% by mass was prepared. At this time, KBM-403, MCR-E11, KBE-9007N and AKZ947 were blended in a blending ratio (solid content amount) of 88.0 mol%: 1.0 mol%: 5.0 mol%: 6.0 mol%. The amount of water blended was adjusted so that R _OR was 1.0. Here, R _OR means the required molar ratio of water to the condensation point of the silane compound used. For example, the minimum number of water molecules required to condense a silane compound having one trimethoxy group is three. Let this relationship be R _OR = 1.0. The optimum R _OR range is 1.0 ≤ R _OR ≤ 2.0.

Next, as an acid generator, TAG-2689 (trade name, manufactured by Kusumoto Kasei Co., Ltd., quaternary ammonium salt-based thermoacid generator) or CPI-310S (trade name, manufactured by San-Apro Co., Ltd., triarylsulfonium salt-based). (Photoacid generator) is dissolved in acetone, adjusted to 10% by mass, and by adding 0.35 g of a 10% by mass acid generator solution to 100 g of a condensate-containing alcohol solution, thermosetting is performed. A coating solution and a photocurable coating solution were prepared.

<Manufacturing of Conductive Base A>
[Preparation of materials for forming elastic layer]
Epichlorhydrin rubber (manufactured by Daiso Co., Ltd., "Epichromer CG-102") 100.00 parts by mass as a rubber component, sorbitan fatty acid ester (Kao Co., Ltd., "Splendor R-300") 5.00 parts by mass, softened 5.00 parts by mass of lysinolic acid as an agent, 0.50 parts by mass of a hydrotalcite compound ("DHT-4A" manufactured by Kyowa Chemical Industry Co., Ltd.) as an acid receiving agent, and tetrabutylammonium chloride (ion conductive) as a conductive agent. Agent) (manufactured by Tokyo Kasei Kogyo Co., Ltd., "Tetrabutylammonium chloride") 1.00 parts by mass, silica as a filler (manufactured by Toso Silica Co., Ltd., "Nipsil ER") 50.00 parts by mass, cross-linking accelerator 5.00 parts by mass of zinc oxide, 1.50 parts by mass of dibenzothiazole sulfide and 0.50 parts by mass of tetramethylthiummonium monosulfide, and 1.05 parts by mass of sulfur as a cross-linking agent are blended and kneaded using a predetermined roll. By doing so, a material for forming an elastic layer was prepared.

[Preparation of coating liquid 1 for forming a resin layer]
Thermoplastic N-methoxymethylated 6-nylon (manufactured by Nagase ChemteX Corporation, "Tresin F-30K") by 100.00 parts by mass in THF (tetratetra) as a polymer component, methylenebisethylmethylaniline as a curing agent. (Made by Ihara Chemical Industry Co., Ltd., "Cure Hard-MED") 5.00 parts by mass, and carbon black (electronic conductive agent) as a conductive agent (Made by Denka Co., Ltd., "Denka Black HS100") 18.00 mass The parts were mixed. Amorphous nylon resin particles (“Olgasol series” manufactured by Alchema) having different average particle diameters (25.0 μm and 5.0 μm) as the first particles 31 and the second particles 32 are added to this mixed solution. Two types were added and the mixture was sufficiently stirred until the solution became uniform. The addition amount was adjusted so that the content of the first particles 31 was 25% by mass and the content of the second particles 32 was 5% by mass based on the total amount of the obtained resin layer 3. Then, each component in the solution was dispersed using two rolls. As a result, the coating liquid 1 for forming the resin layer was prepared.

The average particle diameters of the first particle 31 and the second particle 32 were measured as follows. That is, 100 particles were arbitrarily extracted from the population of a plurality of particles by SEM observation, and the average value of their particle diameters was taken as the average particle diameter of the resin particles. Since the particle shape of the resin particles used was irregular, the simple average value of the longest diameter and the shortest diameter of the observed particles was taken as the particle diameter of each particle.

[Manufacturing of conductive base A]
A roll forming die having a columnar roll forming space was prepared, and a core metal (conductive support 1) having a diameter of 8 mm coated with a conductive adhesive was set so as to be coaxial with the roll forming space. The elastic layer forming material prepared as described above was injected into the roll forming space in which the core metal was set, heated at 170 ° C. for 30 minutes, cooled and demolded. As a result, the conductive support 1 as the conductive shaft and the thickness of 2 mm (thickness at the center position in the rotation axis L direction) formed along the outer peripheral surface of the conductive support 1 A base roll comprising the elastic layer 2 was obtained.

Next, the resin layer forming coating liquid 1 prepared as described above was applied to the surface of the elastic layer 2 of the base roll by the roll coating method. At this time, the coating was performed while cutting off unnecessary coating liquid with a scraper so as to obtain a desired film thickness. After forming the coating film, it was heated at 150 ° C. for 30 minutes to form a resin layer 3 having a layer thickness of A = 5.0 μm. As a result, a conductive base A including an elastic layer 2 formed along the outer peripheral surface of the shaft body (conductive support 1) and a resin layer 3 formed along the outer peripheral surface of the elastic layer 2 is produced. bottom.

<Manufacturing of conductive base B>
After applying a conductive adhesive to the upper part of the conductive support 1 (core metal having a diameter of 8 mm) as the conductive shaft, the elasticity prepared in the above-mentioned "Manufacturing of the conductive base A" along the outer peripheral surface thereof. By extrusion molding the layer forming material, an elastic layer having a thickness of 3 mm (thickness at the center position in the L direction of the rotation axis) is formed, and the end portion is cut and polished so as to have a predetermined elastic layer length. By doing so, a base roll having a crown shape was obtained. Next, 20 parts by mass of an isocyanate compound (MDI: manufactured by DIC Corporation) was added to 100 parts by mass of ethyl acetate, mixed and dissolved to obtain an isocyanate solution. Next, an isocyanate solution was applied to the surface of the elastic layer of the base roll, and then the portion impregnated with the isocyanate solution was cured to form a resin layer 3 having a thickness of 50 μm. Specifically, after immersing the base roll in the isocyanate solution for 30 seconds while keeping the temperature of the isocyanate solution at 23 ° C., the base roll is taken out and the removed base roll (the base in which the isocyanate solution impregnates the surface) is taken out. The resin layer 3 was formed by heating the roll) in an oven maintained at 120 ° C. for 1 hour. As a result, a conductive base B including an elastic layer 2 formed along the outer peripheral surface of the shaft body (conductive support 1) and a resin layer 3 formed along the outer peripheral surface of the elastic layer 2 is produced. bottom.

<Manufacturing of conductive base C>
[Preparation of coating liquid 2 for forming a resin layer]
Thermoplastic N-methoxymethylated 6-nylon (manufactured by Nagase ChemteX Corporation, "Tresin F-30K") by 100.00 parts by mass in THF (tetratetra) as a polymer component, methylenebisethylmethylaniline as a curing agent. (Made by Ihara Chemical Industry Co., Ltd., "Cure Hard-MED") 5.00 parts by mass, and carbon black (electronic conductive agent) as a conductive agent (Made by Denka Co., Ltd., "Denka Black HS100") 18.00 mass The parts were mixed. Amorphous nylon resin particles (“Olgasol series” manufactured by Alchema) having different average particle diameters (10.0 μm and 5.0 μm) as the first particles 31 and the second particles 32 are added to this mixed solution. Two types were added and the mixture was sufficiently stirred until the solution became uniform. The addition amount was adjusted so that the content of the first particles 31 was 25% by mass and the content of the second particles 32 was 5% by mass based on the total amount of the obtained resin layer 3. Then, each component in the solution was dispersed using two rolls. As a result, the coating liquid 2 for forming the resin layer was prepared.

The average particle diameters of the first particle 31 and the second particle 32 were measured as follows. That is, 100 particles were arbitrarily extracted from the population of a plurality of particles by SEM observation, and the average value of their particle diameters was taken as the average particle diameter of the resin particles. Since the particle shape of the resin particles used was irregular, the simple average value of the longest diameter and the shortest diameter of the observed particles was taken as the particle diameter of each particle.

[Manufacturing of conductive base C]
A roll forming die having a columnar roll forming space was prepared, and a core metal (conductive support 1) having a diameter of 8 mm coated with a conductive adhesive was set so as to be coaxial with the roll forming space. The elastic layer forming material prepared in the above-mentioned "Manufacturing of Conductive Base A" was injected into the roll forming space in which the core metal was set, heated at 170 ° C. for 30 minutes, cooled and demolded. As a result, the conductive support 1 as the conductive shaft and the thickness of 2 mm (thickness at the center position in the rotation axis L direction) formed along the outer peripheral surface of the conductive support 1 A base roll comprising the elastic layer 2 was obtained.

Next, the resin layer forming coating liquid 2 prepared as described above was applied to the surface of the elastic layer 2 of the base roll by the roll coating method. At this time, the coating was performed while cutting off unnecessary coating liquid with a scraper so as to obtain a desired film thickness. After forming the coating film, it was heated at 150 ° C. for 30 minutes to form a resin layer 3 having a layer thickness A = 15.0 μm. As a result, a conductive base C including an elastic layer 2 formed along the outer peripheral surface of the shaft body (conductive support 1) and a resin layer 3 formed along the outer peripheral surface of the elastic layer 2 is produced. bottom.

<Examples 1 to 19 and Comparative Examples 1 to 6>
(Manufacturing of charging roller 10)
The heat-curable coating liquid or photo-curable coating liquid prepared above is used as a conductive base A, B or C prepared above using an air brush (manufactured by Tamiya Co., Ltd., trade name: Spraywork HG single air brush). The surface of the coating was coated to form a coating film (coating liquid film) having droplets. The coating was carried out at the spray injection amount shown in Table 1 by setting the needle setting of the airbrush (the number of rotations of the needle adjustment dial from the closed state) to the value shown in Table 1. After forming the coating film, the coating film is cured by heating at 160 ° C. for 20 minutes when a thermosetting coating solution is used, and when a photocurable coating solution is used, UV irradiation equipped with a UV-LED light source is provided. The coating film was cured by irradiating light having a wavelength of 365 nm with an integrated light amount of mJ / cm ² using an apparatus (manufactured by Heleus). As a result, the coating layer 4 having the protrusions 4a was formed.

By the above operation, the shaft body (conductive support 1), the elastic layer 2 formed along the outer peripheral surface of the shaft body, the resin layer 3 formed along the outer peripheral surface of the elastic layer 2, and the resin layer 3 A charging roller 10 including a conductive main body 5 made of a coating layer 4 formed along the outer peripheral surface of the above surface was manufactured. Since the coating liquid contains a hydrolyzable silane and a zirconium chelate compound, the coating layer 4 contains a polysiloxane compound having a Si—O—Zr bond in its molecular structure.

(Measurement of average diameter of protrusion 4a)
The average diameter of the protrusions 4a of the coating layer 4 was measured by the following method. The average diameter of the protrusion 4a is an average value of the diameters of the protrusion 4a confirmed when the protrusion 4a is observed on a plane. Specifically, first, using KEYENCE VK-X121 (lens magnification × 100), the coating layer 4 was observed from above in the range of 107 μm × 143 μm, the diameter of the protrusions in the observation range was measured, and the average of these was measured. The value was calculated. The same operation was performed at 6 places, the diameters (average values) of the protrusions obtained for each place were averaged, and the obtained values were taken as the average diameter of the protrusions. When the diameter was less than 4 μm, it was not regarded as a protrusion and was not included in the measurement target. When the shape of the protrusion in the plan view is not a perfect circle, the average value of the longest diameter and the shortest diameter is taken as the diameter of the protrusion. The measurement results are shown in Table 1. Further, for reference, a plan photograph of the coating layer of Example 1 observed at the time of measurement is shown in FIG. In addition, it was described that the protrusion 4a was not formed when the injection amount was too small or when the injection amount was too large and dripping occurred, so that the average diameter in Table 1 cannot be formed.

(Measurement of Rsk and Rzjis on the surface of the conductive body 5)
The surface roughness (Rsk) and ten-point average roughness (Rzjis) of the conductive main body 5 were measured by a method based on JIS B0601-2001, using a surface roughness measuring instrument SE-3400 manufactured by Kosaka Laboratory Co., Ltd. The cutoff value was 0.8 mm, the measurement speed was 0.5 mm / s, and the measurement length was 8 mm. With this measuring instrument, arbitrary 6 points on the surface of the conductive main body 5 were measured, and the average value of the 6 points was taken as each measured value. The results are shown in Table 1.

(Measurement of surface free energy)
Regarding the outermost surface of the charging roller 10 (the surface of the coating layer 4), the contact angle θ with respect to the three types of probe liquids shown in Table 2 below is measured by a contact angle meter (trade name: CA-X ROLL type, manufactured by Kyowa Interface Science Co., Ltd.). Was measured using. The measurement conditions for the contact angle were as follows.
[Measurement condition]
・ Measurement: Sessile drop method (round fitting)
・ Liquid volume: 1 μL
・ Drop recognition: Automatic ・ Image processing: Algorithm-Non-reflective ・ Image mode: Frame ・ Threshold level: Automatic

In Table 2 above, γ _L ^d , γ _L ^p and γ _L ^h represent the dispersion component, the dipole component and the hydrogen bond component in the probe liquid, respectively. Each component (γ _L ^d , γ _L ^p , γ _L ^h ) of the three types of probe liquids in Table 2 above and the contact angle θ with respect to each probe liquid obtained by measurement are calculated by the following theoretical formula (calculation formula) of Kitazaki and Hata. Substituting into (1)), three equations for each probe liquid are created, and by solving these three simultaneous equations, the dispersion component (γ _S ^d ) and the ^dipole component (γ _Sp ) in the coating layer 4 are obtained. ) And the hydrogen binding component ( ^{γ Sh} ₎ were calculated. Then, the ^sum of ^γ _S ^d , γ _Sp , and γ _Sh was taken as the surface free energy (γ _S ^Total ). The results are shown in Table 3.

(Evaluation of surface stains)
A charging member (charging roller 10) obtained as described above was incorporated into a Samsung Multixpress C8640ND as an image forming apparatus, and an image was formed according to the following conditions.
[Image formation conditions]
-Printing environment: Under low temperature and low humidity environment (15 ° C / 10% RH)
-Printing conditions: normal printing speed of 305 mm / sec and its half speed, number of printed sheets (80 kPV), type of paper (OfficePaperEC)
-Load on the end of the conductive support: 5.88N on one side
-Applied bias: Determined by adjusting for convenience so that the surface potential of the photoconductor is -600V.

Next, the surface stain of the charging roller 10 after image formation was evaluated. Since the surface stain of the charging roller 10 is mainly derived from silica, which is an external additive used in toner, a fluorescent X-ray measuring device (EDXL300: manufactured by Rigaku Co., Ltd.) is used, and the element Si on the surface of the charging roller 10 is used. Was quantified to evaluate the degree of contamination. Specifically, in the chamber of the fluorescent X-ray measuring device, the charging roller 10 was arranged so that the center of the charging roller 10 came to the upper part of the detector, and the element Si on the surface of the charging roller 10 was quantified. This measurement was carried out for each of the charged rollers 10 before and after image formation (every 20 kPV), and the difference in Si amount ΔSi [cps / mA] (= Si amount after endurance test [cps / mA] -before endurance test. Si amount [cps / mA]) was determined. Next, the total number of rotations of the photoconductor was plotted horizontally with this ΔSi on the vertical axis, and the surface stain was evaluated using the slope of the obtained graph as an index. The smaller the inclination, the smaller the ΔSi with respect to the number of rotations of the photoconductor, which means that the stain is less likely to be attached by the external additive. The results are shown in Table 3.

(Evaluation of image formability (charge uniformity))
As an image forming apparatus, a charging member (charging roller 10) obtained as described above was incorporated in a Samsung Multixpress C8640ND, and a halftone image was output according to the following conditions.
Printing environment: Normal temperature and humidity environment (23 ° C / 60% RH)
Printing conditions: Normal printing speed of 305 mm / sec and its half speed, number of prints (180 kPV, 360 kPV, 2 points), paper type (OfficePaperEC)
Load on the end of the conductive support: 5.88N on one side
Applied bias: Determined by adjusting for convenience so that the surface potential of the photoconductor is −600 V.

The microjitter appearing in the halftone image was visually observed and evaluated based on the following criteria. The evaluation results are shown in Table 3. Note that microjitter is one of the indexes for evaluating charge uniformity. Micro-jitter was observed at the initial stage of image formation (initial stage) and after the durability test (after run) to see if stable charge uniformity could be obtained over a long period of time.
Evaluation A: A uniform halftone image was obtained.
Evaluation B: Slight charging unevenness occurred at the edge of the image.
Evaluation C: Charging unevenness clearly occurred at the edge of the image.
Evaluation D: Charging unevenness occurred on the entire surface of the image.

Although various examples of the charging member have been specifically described above, it is clear to those skilled in the art that various modifications and changes can be made without departing from the spiritual scope of the claims. That is, it is intended that all changes are included within the scope of the spirit described in the claims.

1 ... Conductive support, 2 ... Elastic layer, 3 ... Resin layer, 4 ... Coating layer, 4a ... Protrusions, 5 ... Conductive body, 10 ... Charging roller (charging member), 30 ... Matrix material, 31 ... First Particle, 32 ... second particle, L ... rotation axis.

Claims (15)

A charging member including a conductive support and a conductive main body provided on the conductive support.
The conductive body is
An elastic layer provided on the conductive support and
The resin layer provided on the elastic layer and
A coating layer containing a polysiloxane compound provided on the resin layer so as to form the outermost surface of the conductive main body, and a coating layer containing the polysiloxane compound.
Equipped with
The coating layer is substantially dome-shaped and has protrusions having an average diameter of about 4 to 16 μm along the outermost surface of the conductive body.
The outermost surface of the conductive body is a charged member having a skewness (Rsk) of about 1.0 to 3.2 and a ten-point average roughness (Rzjis) of about 11.5 to 32.0 μm. The charging member according to claim 1, wherein the polysiloxane compound has a crosslinked structure derived from an epoxy group. The charging member according to claim 1, wherein the polysiloxane compound has a Si—O—Zr bond in its molecular structure. The charging member according to claim 1, wherein the polysiloxane compound has a structure represented by the following formula (9).

[In formula (9), R ¹⁴ to R ¹⁸ each independently represent an alkyl group having 1 to 4 carbon atoms, r represents an integer of 10 to 100, and Y represents a divalent organic group. * Indicates a bond to Si. ] The charging member according to claim 4, wherein Y in the formula (9) has an oxazolidone ring in the main chain. The charging member according to claim 1, wherein the surface free energy of the coating layer is about 35.0 mJ / m ² or less. It is a manufacturing method of charged members.
Spraying the coating liquid onto the surface of the conductive base provided on the conductive support,
here,
The conductive base comprises an elastic layer and a resin layer provided on the elastic layer and having a coated surface.
The coating liquid contains a composition containing a hydrolyzable silane compound that forms droplets on the surface of the conductive base.
Curing the composition to form a coating layer with protrusions formed from the droplets on the conductive base.
here,
The protrusions are substantially dome-shaped and have an average diameter of about 4 to 16 μm.
The coating layer forms the outermost surface having a skewness (Rsk) of about 1.0 to 3.2 and a ten-point average roughness (Rzjis) of about 11.5 to 32.0 μm.
A method for manufacturing a charged member. The method for producing a charged member according to claim 7, wherein the composition contains a hydrolyzable silane compound having an epoxy group and an acid generator. The acid generator is a photoacid generator,
The method for manufacturing a charged member according to claim 8, wherein the composition is cured by irradiating light having a wavelength of 365 to 405 nm with a UV-LED light source. The acid generator is a thermal acid generator,
The method for producing a charged member according to claim 8, wherein the composition is cured by heating at 250 ° C. or lower. The method for producing a charged member according to claim 7, wherein the composition contains a zirconium chelate compound. Hydrolysis of the composition having a one-ended modified silicone compound having a structure represented by the following formula (16) and a functional group capable of reacting with the reactive group of the one-ended modified silicone compound to form a bond. The method for producing a charged member according to claim 7, which contains a sex silane compound.

[In formula (16), R ¹⁴ to R ¹⁸ each independently represent an alkyl group having 1 to 4 carbon atoms, r represents an integer of 10 to 100, and A is a single bond or a divalent organic substance. The group indicates a group, and U indicates a reactive group. ] The method for producing a charged member according to claim 12, wherein the reactive group is an epoxy group and the functional group is an isocyanate group. The method for manufacturing a charged member according to claim 7, wherein the surface free energy of the coating layer is about 35.0 mJ / m ² or less. An image forming apparatus including a photoconductor and a charging member for charging the photoconductor.
The charged member includes a conductive support and a conductive main body provided on the conductive support.
The conductive body is
An elastic layer provided on the conductive support and
The resin layer provided on the elastic layer and
A coating layer containing a polysiloxane compound provided on the resin layer so as to form the outermost surface of the conductive main body, and a coating layer containing the polysiloxane compound.
Equipped with
The coating layer is substantially dome-shaped and has protrusions having an average diameter of about 4 to 16 μm along the outermost surface of the conductive body.
An image forming apparatus having an outermost surface of the conductive body having a skewness (Rsk) of about 1.0 to 3.2 and a ten-point average roughness (Rzjis) of about 11.5 to 32.0 μm.

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