JP5869912B2 - Conductive member, process cartridge, and electrophotographic image forming apparatus - Google Patents

Description

  The present invention relates to a conductive member, a process cartridge, and an electrophotographic image forming apparatus used in an electrophotographic image forming apparatus.

Along with the diversification of usage environments of electrophotographic image forming apparatuses in recent years, it has been required for electrophotographic image forming apparatuses to be able to form high-quality electrophotographic images regardless of the usage environment. ing. Specifically, in both high temperature and high humidity environment (for example, temperature 30 ° C./humidity 80% RH) and low temperature and low humidity environment (for example, temperature 15 ° C./humidity 10% RH), the quality is stable and high. There is a need to be able to provide electrophotographic images.
However, in reality, in a high temperature and high humidity environment, fog due to a decrease in frictional chargeability of the toner may occur in the electrophotographic image. On the other hand, in a low-temperature and low-humidity environment, the surface hardness of the conductive member used for the developing member for carrying and transporting the toner on the surface in the developing device increases, thereby increasing the stress applied to the toner, In some cases, the toner is fused to the surface of the developing member.

  Further, as the process speed of the electrophotographic image forming apparatus increases, defects such as wear and cracks may occur on the surface of the developing member. As a result, when the solid image is formed due to the fusion of the toner to the surface of the developing member starting from the defect or the decrease in the toner conveyance capability, the density of the rear end portion of the solid image may decrease. .

In Patent Document 1, for the purpose of imparting stable chargeability to a toner in a high-temperature and high-humidity environment and / or long-term use, the shaft core has an elastic layer on its outer periphery, and further has a glass transition temperature around it. Disclosed is a conductive member having a surface layer containing at least two types of polyester resins different from each other.
Further, Patent Document 2 uses a developing roller having a dielectric portion whose surface is regularly or irregularly distributed in a minute area and a grounded conductive portion, and uses a number of minute closed electric fields near the surface of the developing roller. It has been proposed that a large amount of toner is deposited on the toner carrier by the action of this closed electric field. In Patent Document 3, as a specific configuration of a toner carrier that forms a minute closed electric field, a conductive material is dispersed in a dielectric material, and this mixture is applied onto a cored bar to form a dielectric on the surface. Dispersion type that exposes the part, conductive material in the dielectric material is melted by wrapping the dispersion fiber, and the dielectric part is dispersed and dispersed, and vertical and horizontal grid-like grooves are formed in the conductive substrate. And the knurled type which embeds thermosetting resin in this groove | channel is disclosed.

JP 2001-109254 A JP-A-6-180533 JP-A-8-286497

  However, according to the examination of the inventions according to Patent Documents 1 to 3 by the present inventors, the present invention can be applied as a charging member or a developing member to an electrophotographic image forming apparatus having a high process speed, and can be applied at high temperature and high humidity or low temperature and low humidity. Even in such an environment, in order to obtain a conductive member having stable performance as a charging member or a developing member, it has been recognized that further technical development is necessary.

Accordingly, an object of the present invention is to provide performance as a charging member or a developing member in an environment of high temperature and high humidity or low temperature and low humidity when used as a charging member or a developing member in an electrophotographic image forming apparatus having a high process speed. It is to provide a conductive member that is stable.
Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus capable of stably forming a high-quality electrophotographic image under various environments.

（式（Ｂ）中、Ｒ_１は炭素数２以上９以下の直鎖アルキレン基、もしくは炭素数６以上９以下の分岐鎖状アルキレン基であり、Ｒ_２は炭素数２以上８以下の直鎖アルキレン基である。）。 According to one aspect of the present invention, there is provided a conductive member having a shaft core body, an elastic layer on the outer periphery of the shaft core body, and a surface layer on the outer periphery of the elastic layer. A polyester melamine resin containing formulas (A), (B) and (C); a polyester copolymer resin comprising the following formulas (A) and (B); and conductive fine particles, There is provided a conductive member in which a matrix phase is formed in the surface layer, the polyester copolymer resin forms a domain phase in the surface layer, and the conductive fine particles are unevenly distributed in the matrix phase.

(In the formula (B), R ₁ is a straight chain alkylene group having 2 to 9 carbon atoms or a branched alkylene group having 6 to 9 carbon atoms, and R ₂ is a straight chain group having 2 to 8 carbon atoms. An alkylene group).

  According to another aspect of the present invention, a process cartridge is detachably attached to the main body of the electrophotographic image forming apparatus, and the process cartridge includes at least a conductive member, a toner regulating member, and a toner container. A process cartridge is provided, characterized in that the conductive member is the conductive member described above.

  Furthermore, according to another aspect of the present invention, there is provided an electrophotographic image forming apparatus having a photosensitive member and a conductive member disposed in contact with the photosensitive member, wherein the conductive member is the conductive member described above. An electrophotographic image forming apparatus is provided.

  According to the present invention, it is possible to obtain a conductive member that contributes to the formation of a high-quality electrophotographic image stably even under various environments. Further, according to the present invention, an electrophotographic image forming apparatus and a process cartridge capable of stably forming a high-quality electrophotographic image under various environments can be obtained.

It is sectional drawing perpendicular | vertical with respect to the longitudinal direction of the electroconductive member which concerns on this invention. It is sectional drawing parallel to the longitudinal direction of the surface vicinity of the electroconductive member which concerns on this invention. It is explanatory drawing of the liquid circulation type dip coating apparatus used in order to form the surface layer of the electroconductive member which concerns on this invention. It is sectional drawing of the process cartridge which concerns on this invention. 1 is a cross-sectional view of an electrophotographic image forming apparatus according to the present invention.

Hereinafter, the present invention will be described in detail with reference to an example in which the conductive member according to the present invention is used as a developing member.
As a result of repeated studies on the above object, the present inventors have found that a conductive member that satisfies the following requirements (1) to (4) can achieve the above object well.

(1) The surface layer of the conductive member forms a phase separation structure having a domain phase and a matrix phase;
(2) The domain phase is composed of a polyester copolymer resin composed of the following formulas (A) and (B),
(3) The matrix phase is composed of a polyester melamine resin containing the following formulas (A), (B) and (C), and
(4) Conductive fine particles are unevenly distributed in the matrix phase.

  FIG. 1 is a cross-sectional view perpendicular to the longitudinal direction of a conductive member according to the present invention. The conductive member 1 includes a columnar or hollow cylindrical conductive shaft core 2, at least one elastic layer 3 formed on the outer periphery of the shaft core, and a surface layer formed on the outer periphery of the elastic layer. 4.

<Surface layer>
FIG. 2 is a cross-sectional view parallel to the longitudinal direction of the conductive member according to the present invention. The surface layer 4 has a phase separation structure (hereinafter also simply referred to as “phase separation structure”) composed of a matrix phase 4a and a domain phase 4b. In the matrix phase 4a, the conductive fine particles 4c are unevenly distributed in the matrix phase 4a.

  In the conductive member according to the present invention, the surface layer formed on the outer periphery of the elastic layer has a phase separation structure, and the conductive fine particles 4c are unevenly distributed in the matrix phase 4a. In other words, the surface layer formed by interspersing the conductor portion and the dielectric portion is compatible with the suppression of image follow-up failure due to insufficient toner fusion and toner conveyance amount when used as a developing member. is important. In addition, the selection of the material constituting the conductor part and the dielectric part is particularly effective when the electrophotographic image is output at a high process speed, the surface layer is scraped and cracked, and the electrophotographic image in a high-temperature and high-humidity environment. It is important to suppress the occurrence of fogging.

In general, it is known that the following method is used for an insufficient amount of toner transported by the developing member that causes an image following failure.
(1) The toner supply amount is increased by increasing the peripheral speed ratio of the conductive member to the photosensitive member.
(2) Increasing the contact pressure between the toner regulating member and the conductive member and opening the toner intake port (wedge) increases the toner intake amount.
(3) The physical transportability is increased by increasing the uneven shape on the surface of the conductive member.

However, in the methods (1) and (2), since the shear resistance between the photosensitive member or the toner regulating member and the developing member is increased, the stress on the toner is increased, and the toner fusion may be deteriorated. .
On the other hand, in the method (3), the surface unevenness is increased, and the toner supply roller cannot sufficiently enter the toner layer, that is, the surface layer of the developing member. For this reason, toner scraping may be insufficient, and the residual toner may be repeatedly stressed with the contact member, resulting in toner fusion.
Furthermore, as the process speed increases, the amount of toner supply needs to increase in order to suppress poor image following and the shear resistance due to friction between the toner and the contact member tends to increase. There is a tendency that chipping and cracking easily progress. Further, with the increase in the speed of image output, fogging in a high temperature and high humidity environment tends to deteriorate. This is because the absolute amount of the amount of toner carried on the conductive member per process increases as the peripheral speed ratio of the conductive member to the photosensitive member decreases, so that the charge per toner is obtained by friction. This is because the amount decreases.

Further, particularly in a high-temperature and high-humidity environment, toner charging shortage that causes fogging is estimated to be due to the following factors.
(1) Since the humidity is high (there is a lot of water), the toners easily aggregate due to the liquid crosslinking force, so that the toner rolling property is deteriorated and the frequency of receiving the rolling friction at the time of rubbing decreases.
(2) Since the molecular mobility of the conductive member surface and the toner resin material is increased due to the high temperature, the intermolecular force (tack property) acting between the conductive member surface and the toner surface is increased, Toner rolling property is deteriorated.
(3) Due to the presence of a large amount of moisture, the toner charge charged by frictional charging with the toner regulating member or conductive member in contact with the toner tends to be attenuated.

  Therefore, in order to suppress fogging in a high-temperature and high-humidity environment, it is necessary to suppress deterioration of toner slidability due to increased tackiness and effectively suppress toner charge attenuation in a conductive member. is there.

Accordingly, in order to achieve both the effects of the present invention at a high level under high-speed image output, it is necessary to simultaneously achieve the following technical requirements in the conductive member.
(1) Increase in toner suction force,
(2) Improving toner rolling properties and suppressing charge decay,
(3) Suppression of surface layer scraping and cracking,
(4) Alleviating stress on the toner during sliding.

  In view of the above technical background, the present inventors have intensively studied. As a result, the surface layer of the conductive member has a domain phase 4b containing a polyester copolymer resin composed of the following chemical formulas (A) and (B), and a polyester containing the following chemical formulas (A), (B), and (C). It has been found that the above requirements can be achieved by having a phase separation structure composed of a melamine resin matrix phase 4a and having the conductive fine particles 4c unevenly distributed in the matrix phase.

In the formula (B), R ₁ is a linear alkylene group having 2 to 9 carbon atoms or a branched alkylene group having 6 to 9 carbon atoms, and R ₂ is a linear alkylene group having 2 to 8 carbon atoms. It is a group.

In the conductive member according to the present invention, in the surface layer, the domain phase composed of the dielectric portion and the matrix phase where the conductive fine particles composed of the conductor portion are unevenly distributed are exposed in a minute area.
The dielectric portion is charged by being rubbed through the toner by a contact member such as a toner regulating member, and forms a minute closed electric field on a portion adjacent to the conductor portion. At this time, an electric field gradient is formed between the dielectric portion and the adjacent conductor portion. The toner conveyed to the surface of the conductive member receives an electric field gradient force (gradient force) due to a minute closed electric field, and is attracted and carried on the surface of the conductive member. This is because the toner is attracted by the action of receiving repulsion from the conductive surface against the surface charge on the dielectric surface and the different polarity toner. The toner attracting action due to the electric field effect is less dependent on the distance between the adherend and the adherend than the generally known toner adherence such as intermolecular force and mirror image force. It is possible to suck. Therefore, with the above-described configuration, it is possible to easily increase the toner conveyance amount, and to suppress image tracking failure even when an electrophotographic image is output at high speed. Further, the surface layer of the present invention does not need to form excessive irregularities on the surface layer or excessively increase the contact pressure with the toner regulating member in order to increase the toner carrying amount. It can be effectively suppressed.

  Furthermore, the domain phase includes a polyester copolymer resin that is a copolymer of a chemical formula (A) derived from polyethylene terephthalate (hereinafter also referred to as “PET”) and a chemical formula (B) derived from an aliphatic ester. And The matrix phase includes a polyester melamine resin which is a cross-linking reaction product between a polyester copolymer resin having chemical formulas (A) and (B) and a melamine resin represented by chemical formula (C).

  First, the PET resin that is a starting material of the chemical formula (A) will be described. The PET resin is a polyester resin synthesized by an esterification reaction using ethylene glycol and terephthalic acid as starting materials. In general, a PET resin has high crystallinity and is rigid in terms of molecular structure, and therefore has low adhesion due to intermolecular force and excellent toughness. Furthermore, it is excellent in electret property (low charge attenuating property) among resin materials, and exhibits high triboelectric chargeability. Therefore, by including the segment (functional group) of the chemical formula (A) in the surface layer, it is possible to exhibit excellent toner mobility even under a high temperature and high humidity environment. Furthermore, since the electret property is excellent, the toner charge attenuation can be suppressed, which contributes to the suppression of fog due to insufficient toner charging.

  Subsequently, the aliphatic ester which is a starting material of the chemical formula (B) will be described. The surface layer of the present invention contributes to the development of flexibility due to the presence of the segment of the chemical formula (B), suppresses the surface layer from being scraped and cracked, and alleviates the stress applied to the toner during sliding. I can do it. This is for the following reason.

(1) Control of crystallinity of segment of chemical formula (A)
The PET resin, which is the starting material for the segment of the chemical formula (A), is difficult to dissolve in various solvents among resin materials, and the softening temperature of the resin is high, so a coating film is formed as a surface layer on an elastic layer such as a rubber material. Is difficult to form. For example, when a PET resin is melted by heat to form a coating film, it is necessary to melt the PET resin at a melting point (about 260 ° C.) or higher, and the underlying elastic layer may be thermally decomposed or damaged. In addition, when a coating film is formed by dissolving in a solvent or the like, the PET resin has low solubility in the solvent or the like, and further has high crystallinity, so that crystals may precipitate during the formation of the coating film. In this case, if irregularities due to crystalline precipitates are formed on the surface of the coating film, when an elastic roller is used, toner fusion proceeds from the convex portion, and scraping or cracking occurs when the roller slides. It may be easy to do. Therefore, in order to form the surface layer including the segment of the chemical formula (A), it is necessary to reduce the structural regularity of the PET resin, to optimize the crystallinity and to improve the solubility in the solvent. As a general method, a method in which two or more kinds of polymers having different structures are mixed and random copolymerized or block copolymerized can be mentioned. At this time, selection of a polymer to be copolymerized with the PET resin is important. If the compatibility with the polymer to be copolymerized is poor, a large amount of the polymer to be copolymerized is required in order to obtain appropriate crystallinity, and it becomes difficult to develop the characteristics unique to the PET resin. Moreover, if the polymer itself to be copolymerized has high crystallinity, it will be difficult to develop the characteristics unique to the PET resin for the same reason as described above. Accordingly, from the viewpoint of compatibility with the chemical formula (A) and optimization of crystallinity, the chemical formula (B) is an ester resin having a close polarity and good compatibility with the chemical formula (A), and further having low crystallinity. The segment must be derived from an aliphatic ester.

(2) Add soft segment to polyester copolymer resin
The PET resin that is the starting material of the segment of the chemical formula (A) has high rigidity and is inferior in flexibility. Therefore, when a coating film is formed on an elastic body such as a rubber material and used as a sliding member, followability with the base is extremely poor, and peeling and cracking are likely to occur.
Therefore, in the present invention, it is necessary to improve the elastomeric property of the polyester copolymer resin constituting the surface layer and improve the flexibility by the segment derived from the aliphatic ester. The expression of the elastomeric property of the polyester copolymer resin is determined by the cohesive strength of the crystal derived from the PET resin of the chemical formula (A) constituting the hard segment and the molecular motion of the soft segment having a low secondary transition point.
In the present invention, the chemical formula (B) corresponds to a soft segment and plays an important role in the expression of flexibility. The reason is that the aliphatic ester does not have a benzene ring such as that derived from a rigid phenyl group in the molecular structure. Further, by using an aliphatic ester which is a starting material of the chemical formula (B), it is possible to make the crystal size finer when a PET resin and a polyester copolymer resin are formed.
Since the soft segment and the hard segment in the elastomer molecule are incompatible with each other, they are phase-separated microscopically. This micro phase separation state, that is, the morphology, affects the crystal size in the molecular structure and affects the flexibility as an elastomer. Therefore, by causing the soft segment of the chemical formula (B) to be present randomly in the elastomer molecule, an increase in crystal size derived from the PET resin is suppressed, which advantageously acts on the development of the flexibility of the elastomer.

In addition, the aliphatic ester which is a starting material of the chemical formula (B) in the present invention is esterified using an aliphatic diol (corresponding to R ₁ in the formula) and an aliphatic dicarboxylic acid (corresponding to R ₂ in the formula). Synthesized by reaction. The aliphatic diol used as the raw material of the present invention has a straight chain alkylene group having 2 to 9 carbon atoms or a branched alkylene group having 6 to 9 carbon atoms, and examples thereof include the following. . 1,2-ethanediol, trimethylene glycol, 1,3-butanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7- Heptanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, trimethylpropanediol, methyloctanediol. Moreover, you may mix these 2 or more types. If the straight-chain alkylene group has 2 or more carbon atoms, the flexibility of the aliphatic ester resin can be obtained, and sufficient flexibility can be obtained. Moreover, since carbon number of a linear alkylene group is 9 or less, the raise of the excessive crystallinity of an aliphatic ester resin and a polyester copolymer resin can be suppressed, and sufficient flexibility can be obtained. Among these, 1,5-pentanediol and 3-methyl-1,5-pentanediol are particularly preferable from the viewpoint of imparting flexibility and optimizing crystallinity.

  The aliphatic dicarboxylic acid used as a raw material of the present invention has a straight-chain alkylene group having 2 to 8 carbon atoms, and examples thereof include succinic acid, adipic acid, suberic acid, azelaic acid, and sebacic acid. Two or more of these may be mixed. Similar to the aliphatic diols, if the linear alkylene group has 2 or more carbon atoms, the flexibility of the aliphatic ester resin can be obtained, and sufficient flexibility can be obtained. Moreover, since carbon number of a linear alkylene group is 8 or less, the raise of the excessive crystallinity of an aliphatic ester resin and a polyester copolymer resin can be suppressed, and sufficient flexibility can be obtained. Of these, adipic acid or sebacic acid is particularly preferable because of flexibility, crystallinity optimization, and availability.

  Furthermore, what is obtained by ring-opening polymerization reaction of lactones, such as poly (epsilon) -caprolactone, polyenanthlactone, polycaprolactone, polybivalocaprolactone, which are cyclic ester monomers, can be used as the aliphatic ester resin. Polyesters obtained from lactones can be obtained by ring-opening polymerization of lactones without using an alkylene glycol such as ethylene glycol, propylene glycol, or butylene glycol as an initiator, or in the presence of a catalyst. Of these, polyε-caprolactone is particularly preferable from the viewpoint of imparting flexibility and optimizing crystallinity.

  Catalysts used for direct esterification and ring-opening polymerization of lactones include metals such as Li, Sr, Ba, Zn, Mn, Co, Al, Ti, Sn, Sb, and Zr, or organometallics containing these metals. Examples thereof include compounds, organic acid salts, and alkoxides. Among these, organic aluminum compounds, organic titanium compounds, aluminum triethoxide, aluminum acetylacetonate, titanium tetraethoxide, titanium tetrabutoxide, and the like are preferable.

  For the synthesis of a polyester copolymer resin of a PET resin and an aliphatic ester resin, a production method such as a copolymerization method, a melt mixing method, or an addition polymerization method can be used. When a cyclic ester monomer is used as the aliphatic ester resin, an addition polymerization method can be suitably used.

  Mass ratio of PET resin (A) in 100 parts by mass of polyester copolymer resin, that is, parts by mass of PET resin (A) / {mass part of PET resin (A) + mass part of aliphatic ester resin (B)} Is preferably 0.20 to 0.98. Particularly preferred is 0.25 to 0.90. By being in the above mass ratio, it becomes easier to impart flexibility and control crystallinity. In addition, the structural unit of the chemical formula (A) as the hard segment and the chemical formula (B) as the soft segment in the polyester copolymer resin in the present invention is a known unit such as a nuclear magnetic resonance method (NMR method). It is possible to analyze.

  Subsequently, the melamine resin containing the skeleton unit represented by the chemical formula (C) contained in the matrix phase of the surface layer of the present invention will be described. In general, a melamine resin is a thermosetting resin, and is a resin material often used in combination with a polyester resin or an acrylic resin, which are main ingredients. In the present invention, the presence of the melamine resin containing the skeleton unit represented by the chemical formula (C) in the matrix phase contributes as an essential component for the formation of the phase separation structure and the uneven distribution of the conductive fine particles in the matrix phase. This is because the unit of nitrogen-derived six-membered ring structure shown in chemical formula (C) generates a chemical interaction with the conductive fine particles, so that the conductive fine particles are selected as the resin containing the skeleton unit shown in chemical formula (C). This is because it is unevenly distributed.

The melamine resin can impart various functional groups to the skeleton unit represented by the chemical formula (C). Examples thereof include an alkyl group, a methylol group, an imino group, a carboxyl group, and a phenyl group. Furthermore, the skeleton units can be polymerized by extending the chain with a methylene bond or a methylene ether bond. The characteristics of the melamine resin can be controlled by the type of the functional group and the degree of polymerization (molecular weight). The melamine resin in this invention is not specifically limited, For example, a methyl etherified melamine resin, a butyl etherified melamine resin, an isobutyl etherified melamine resin, and an isopropyl etherified melamine resin can be mentioned as a suitable thing. In addition, as an example, methyl etherified melamine resin is a methyl ether obtained by etherifying only a part of or all of methylol groups in methylol melamine resin, which is an addition reaction product of melamine and an aldehyde component such as formaldehyde. It can also be called a melamine resin. Furthermore, at this time, any of the melamine resins obtained by mixing and etherifying some or all of the methylol groups in the methylolated melamine resin with, for example, ethanol, isopropanol, n-propanol, n-butanol, isobutanol or the like is included. Two or more kinds of these functional groups may be mixed in the structure defined in the present invention. The melamine resin in the present invention is not particularly limited as long as it contains the chemical formula (C), but among them, it is preferable to have a flexible segment in the molecular structure of the melamine resin. By having the flexible segment in the molecular structure, the flexibility is sufficiently expressed, and the surface layer of the conductive member can be effectively prevented from being scraped and cracked. Furthermore, it contributes to alleviation of stress applied to the toner when the conductive member slides. Moreover, although mentioned later for details, formation of a phase-separation structure and optimization of the magnitude | size of a domain phase can be achieved by making low polarity of a melamine resin easy. Particularly preferred is a butyl etherified melamine resin from the viewpoint of the long molecular chain length of the alkyl group and flexibility, and the control of the phase separation structure by optimizing the polarity difference from the polyester copolymer resin. The butyl etherified melamine resin can also be referred to as a butylated melamine resin etherified only with butanol.
On the other hand, a benzoguanamine resin or a cyclohexylguanamine resin that does not contain the chemical formula (C) and has a phenyl group that is rigid in molecular structure in the structure has poor flexibility, and may be scraped or cracked. It is not preferable. Further, it is not preferable because the stress applied to the toner during sliding increases. Furthermore, the benzoguanamine resin, cyclohexylguanamine resin, and the like are not preferable because they are close in polarity to the polyester copolymer resin and it is difficult to form a phase separation structure.

  In addition, the number average molecular weight (Mn) of the melamine resin containing the skeleton unit represented by the chemical formula (C) is preferably 500 ≦ Mn ≦ 10000, and particularly preferably 2000 ≦ Mn ≦ 6500. When Mn is 500 or more, an excessive increase in hardness of the matrix phase in the surface layer is suppressed, and an effect of reducing stress applied to the toner is exhibited. Furthermore, sufficient flexibility is obtained. Further, when Mn is 10,000 or less, an increase in the tackiness of the matrix phase can be suppressed, and fogging in a high-temperature and high-humidity environment due to deterioration in toner rolling property can be suppressed.

  Next, specific means for forming a phase separation structure that plays an important role in expressing the effects of the present invention will be described. The surface layer formed around the elastic layer according to the present invention includes a domain phase containing a polyester copolymer resin composed of chemical formulas (A) and (B), and chemical formulas (A), (B), and (C). It exhibits a phase-separated structure consisting of a matrix phase of the polyester melamine resin. Examples of the achievement means for forming such a configuration include the following two methods.

(1) Phase separation structure control using two or more types of resin raw materials having different polarities (SP values)
As a method of forming a coating film having a phase separation structure, a method of forming a phase separation structure by mixing and dissolving two kinds of resin raw materials having different SP values in a solvent and drying the solvent can be mentioned. The SP value is the square root of the cohesive energy density of molecules, and represents the magnitude of the cohesive force between molecules (intermolecular force). Therefore, by optimizing the SP value difference between the two, the mixed (compatible) state is controlled, and the phase separation structure can be controlled. The two types of resin raw materials in the present invention are a polyester copolymer resin composed of the chemical formula (A) and the chemical formula (B) and a melamine resin containing a skeleton unit represented by the chemical formula (C). The SP value of the polyester copolymer resin can be controlled by adjusting the copolymerization ratio between the chemical formula (A) and the chemical formula (B). The SP value of the melamine resin can be easily controlled by selecting a functional group imparted to the skeleton unit of the melamine resin, or selecting a molecular weight that correlates with the abundance ratio of methylene bonds or methylene ether bonds. In the present invention, since the PET resin having a high polarity and the melamine resin having a low polarity are used, the SP value of the melamine resin is relatively low with respect to the SP value of the polyester copolymer resin. is there.

  In the present invention, the difference in SP value between the two resin raw materials is preferably 0.5 or more and 2.1 or less, and particularly preferably 1.0 or more and 1.8 or less. By making the SP value difference within the above range, the two kinds of resin materials can easily control the phase separation structure, and the size of the domain phase can be controlled more easily. Moreover, it can be set as the surface layer excellent in smoothness and mechanical characteristics.

(2) Control of crystallinity (solvent solubility) of polyester copolymer resin
Examples of a method for forming a coating film having a phase separation structure include a method of forming a coating film by dissolving a resin material having high crystallinity and a solid state at room temperature in a supersaturated amount of solvent. A resin material with high crystallinity exhibits the property that crystals are likely to precipitate partially due to volatilization of the solvent during coating film formation. The convex precipitation portion of the crystal becomes a domain portion, and the portion where the coating film is continuously formed becomes a matrix portion, thereby forming a phase separation structure. This domain phase, that is, the degree of crystal precipitation, depends on the crystallinity of the polyester copolymer resin in the present invention. It is important to control the crystal size and the coverage by optimizing the molecular structure of the crystallinity of the polyester copolymer resin. In addition to the optimization of the crystallinity of the resin material, control of the phase separation structure, that is, the size of the domain, can be achieved by the boiling point, evaporation rate, and SP value of the solvent. In the present invention, the phase separation structure is controlled by combining the above-described method and material composition, (1) increase in toner attractive force, (2) improvement in toner rolling property and suppression of charge decay, and (3) surface layer scraping and Suppression of cracking (4) Realization of relaxation of stress applied to toner.

  Specifically, by controlling the shape of the phase separation structure by selecting the resin material that constitutes the surface layer and optimizing the combination, it receives an electric field gradient force (gradient force) due to a minute closed electric field, and image tracking failure There is an effect of suppression. Further, in the surface layer of the present invention, the domain phase is relatively convex than the matrix phase, so that the contact surface between the toner and the toner regulating member or the photoreceptor is more conductive than the matrix phase which is a conductive surface. The domain phase that is the dielectric part has a larger configuration. With such a configuration, charge attenuation via the toner is synergistically suppressed, and a high-dimensional fog suppression effect is achieved by the triboelectric charge imparting property of the PET resin component.

  The surface layer formed by the above method is composed of a domain phase and a matrix phase, and the domain phase is mainly composed of a polyester copolymer resin exhibiting thermoplasticity, but is responsive to deformation. Have This is presumed that since the domain phase and the matrix phase have almost the same composition, the natural frequencies of both are close to each other, and high responsiveness to deformation during sliding is obtained. In addition, since a part of the interface between the domain phase and the matrix phase is cross-linked through an amino bond derived from a melamine resin, plastic deformation at the interface is suppressed, and it is considered that deformation responsiveness is exhibited.

  The surface layer in the present invention has a domain phase in the matrix phase, and the equivalent circle diameter of the domain phase is preferably 5 μm or more and 200 μm or less, although it depends on the average particle diameter of the toner. Especially preferably, they are 10 micrometers or more and 100 micrometers or less. If it is 5 μm or more, the electric field gradient force (gradient force) due to the minute closed electric field can be sufficiently expressed, and the toner suction force can be increased. Furthermore, since a sufficiently large dielectric layer surface can be obtained for toner having an average particle diameter of several μm in general, toner charge attenuation can be suppressed. In addition, when the thickness is 200 μm or less, sufficient toner scraping performance by the toner supply roller can be obtained, and thus toner fusion caused by residual toner due to repeated stress can be suppressed. Furthermore, it is possible to suppress the formation of excessive unevenness, and it is possible to suppress the occurrence of scraping and cracking due to sliding. Here, the equivalent circle diameter refers to the diameter of a circle having the same area as the area of the domain phase projected onto the surface of the conductive member. The domain phase in the present invention can be identified by a scanning electron microscope (SEM), a scanning transmission electron microscope (STEM), or the like.

  As described above, the size of the domain phase (domain size) is controlled in addition to the difference in the SP value of the two types of resin raw materials, the optimization of the crystallinity of the polyester copolymer resin, and the selection of the solvent when forming the surface layer. It can also be achieved by the mass ratio of various resin raw materials. The mass ratio of the polyester copolymer resin to the total mass number of the polyester copolymer resin and the melamine resin is preferably 0.25 or more and 0.92 or less, more preferably 0.30 or more and 0.90 or less. When the mass ratio of the polyester copolymer resin to the total mass number of the polyester copolymer resin and the melamine resin is 0.25 or more, the contribution of the PET resin component can be sufficiently obtained, and the triboelectric chargeability can be easily obtained and the domain can be obtained. It is easy to suppress size reduction. On the other hand, when it is 0.92 or less, the contribution of the melamine resin component is sufficiently obtained, and it is easy to obtain the effects of suppressing scraping and cracking and toner fusion. Furthermore, it becomes easy to suppress an excessive increase in domain size.

Furthermore, in the matrix phase according to the present invention, conductive fine particles are unevenly distributed.
The conductive fine particles contribute to optimization of mechanical properties and conductivity of the surface layer. In addition, it is necessary to make the conductive fine particles unevenly distributed in the matrix phase in order to form a gradient force. Although it does not specifically limit in this invention as a kind of electroconductive fine particle, For example, the following are mentioned. Powders and fibers of metals such as aluminum, palladium, iron, copper, and silver; metal oxides such as titanium oxide, tin oxide, and zinc oxide; furnace black, acetylene black, ketjen black, PAN-based carbon black, pitch-based carbon Carbon-based conductive agents such as black and carbon nanotubes. Among these, carbon black is easy to control conductivity, has excellent wear resistance, and furthermore, it is easy to make it unevenly distributed in the matrix phase by subjecting the conductive fine particles to surface treatment. It can be mentioned as a preferable one.

  The method of uneven distribution of the conductive fine particles in the matrix phase is not particularly limited. However, surface functional groups are imparted to the conductive fine particles, and the glass transition temperature difference between the matrix phase and the domain phase (melting characteristics). For example, a polymer alloying method using a difference) can be used. In this invention, since the melamine resin which has many flexible segments in a matrix phase is contained, the characteristic that the glass transition temperature of a matrix phase is relatively lower than a domain phase is shown. Therefore, in the cooling process after heating, when the domain phase reaches the glass transition temperature, the fluidity sharply decreases, so that the conductive fine particles in the surface layer move into the matrix phase. For the above reasons, it is considered that the conductive fine particles are unevenly distributed in the matrix. Furthermore, it can also be formed by regularly applying a domain phase on a coating film in which a matrix phase is uniformly formed using an inkjet method.

  The conductive fine particles are preferably oxidized conductive fine particles provided with a surface functional group by an oxidation treatment. By forming acidic functional groups such as carboxyl groups on the surface of the conductive fine particles by oxidation treatment, chemical interaction with imino groups and hydroxyl groups in the melamine resin occurs. As a result, the conductive fine particles are selectively dispersed in the melamine resin including the segment of the chemical formula (C), and it is easy to make the conductive fine particles unevenly distributed in the matrix. Furthermore, even if conductive fine particles are used within a range where sufficient conductivity can be imparted, they can be uniformly dispersed, so that aggregation over time can be suppressed, and image defects such as ghosts and occurrence of leaks can be prevented. Can be suppressed. The pH value of the oxidized conductive fine particles is preferably 5.0 or less.

  The content of the conductive fine particles in the surface layer is preferably in the range of 1 to 60 parts by mass with respect to 100 parts by mass of the resin component of the surface layer. At this time, for example, when the mass ratio of the matrix phase to the domain phase is 7: 3, 1.4 to 85.7 parts by mass of conductive fine particles are contained in the matrix phase. More preferably, it is the range of 5-50 mass parts with respect to 100 mass parts of resin components of a surface layer. When the content of the conductive fine particles is 1 part by mass or more, not only an appropriate conductivity of the matrix phase for forming the gradient force can be obtained, but also the mechanical properties and wear resistance of the matrix phase are reduced. Suppression is possible. On the other hand, when the amount is 60 parts by mass or less, dispersion uniformity of the conductive fine particles with respect to the resin component can be obtained, and not only moderate conductivity can be obtained, but also toner fusion due to suppression of an excessive increase in hardness of the matrix phase. It is possible to prevent.

  The average primary particle diameter of the conductive fine particles is preferably 15 to 50 nm in consideration of maintaining the strength of the surface layer resin component and exhibiting appropriate conductivity. The preferable DBP absorption amount of the conductive fine particles is 50 to 300 ml / 100 g, particularly 60 to 180 ml / 100 g for the same reason. By making the DBP absorption amount correlated with the secondary particle diameter of the conductive fine particles within the above range, both dispersibility and wear resistance can be achieved. Furthermore, you may mix | blend 2 or more types of electroconductive fine particles according to a required physical property.

  The surface roughness of the surface layer is preferably 0.10 μm or more and 3.5 μm or less, particularly 0.20 μm or more and 3.0 μm or less in terms of centerline average roughness Ra. If Ra is 0.10 μm or more, it is possible to suppress an increase in adhesiveness on the surface of the conductive member and to suppress fogging in a high-temperature and high-humidity environment due to a decrease in toner rolling property. Furthermore, it is possible to suppress the occurrence of scraping or cracking due to an increase in rubbing with the contact member accompanying an excessive increase in the true contact area. Further, it is possible to suppress the toner transportability from being lowered, and to suppress the occurrence of image tracking failure even under high-speed output. In addition, when Ra is 3.5 μm or less, it is possible to suppress toner fusing due to toner deterioration due to excessive toner conveyance. Although it depends on the combination with the toner and the electrophotographic image forming process, if Ra is within the above numerical range, it is particularly excellent in suppressing the deterioration of the abrasion resistance and crack resistance, and the toner fusing and toner transportability are insufficient. The balance which suppresses the defective image resulting from is good. Examples of methods for obtaining a surface layer having such a surface roughness include optimization of the phase separation structure and a method of incorporating spherical fine particles having an arbitrary particle diameter in the surface layer.

  Ra is based on JIS standard (JISB0601-2001), measured using a surfcoder SE-3400 manufactured by Kosaka Laboratory, under conditions of a feed rate of 0.5 mm / s, a cutoff of 0.8 mm, and a measurement length of 2.5 mm. To do. This measurement is performed at any three locations in the bus bar direction of the conductive member, and a value obtained as an arithmetic average of these values can be adopted as Ra.

  In order to impart the above-mentioned surface roughness to the surface of the conductive member, the surface layer has an uneven shape on the surface of either the domain phase or the matrix phase, or either one, as long as the formation of the phase separation structure is not hindered. You may contain the spherical fine particle to form. When the surface layer contains spherical fine particles, it becomes easy to make the surface roughness of the surface of the conductive member uniform, and at the same time, even when the surface layer is worn, the fluctuation of the surface roughness is reduced and the surface state is kept constant. Can be held in. The spherical fine particles preferably have a volume average particle size of 5 to 30 μm. For measurement of the volume particle size of the fine particles, a laser diffraction particle size distribution measuring device (trade name: LS-230 type; manufactured by Coulter, Inc.) attached with a liquid module can be used. For measurement, a small amount of surfactant is added to about 10 cc of water, about 10 mg of fine particles are added thereto, and the mixture is dispersed for 10 minutes with an ultrasonic disperser, and then measured under the conditions of a measurement time of 90 seconds and a single measurement. . The value measured by the above measurement method can be adopted as the value of the volume average particle diameter. As content of a spherical fine particle, it is preferable that it is 1-100 mass parts with respect to 100 mass parts of resin components of a surface layer.

  Examples of the material for the spherical fine particles include urethane resin, polyester resin, polyether resin, acrylic resin, and polycarbonate resin. These spherical fine particles can be produced, for example, by suspension polymerization or dispersion polymerization.

  In addition to the above components, the surface layer has a filler, an extender, a vulcanizing agent, a vulcanization aid, an antioxidant, an anti-aging agent, a processing as long as it does not inhibit the functions of the above components. Various additives such as auxiliaries can be contained.

  The preferable thickness of the surface layer is 1 to 100 μm, particularly 2 to 30 μm. When the thickness of the surface layer is 1 μm or more, bleeding of the exuding substance contained in the layer below the surface layer can be suppressed, and toner fusion due to increased adhesion can be suppressed. Furthermore, it is possible to easily control the domain size. When the thickness of the surface layer is 100 μm or less, it is possible to suppress the conductive member from having high hardness and to suppress toner fusion. Furthermore, since it becomes easy to control the domain size of the domain phase and the matrix phase, the above range is preferable from the viewpoint of suppressing fogging in a high temperature and high humidity environment. In addition, the film thickness of the formed surface layer uses a digital microscope (VH-2450: Keyence Corporation), and the longitudinal direction of the conductive member is equidistant from the end portion at three locations, and is evenly spaced in the circumferential direction. In addition, the measurement is performed at a total of nine locations, and the arithmetic average value of the obtained values is taken as the film thickness of the surface layer.

<Method for forming surface layer>
The surface layer having the above structure is for forming a surface layer including a resin raw material mixture such as polyester copolymer resin, melamine resin and conductive fine particles shown below on the peripheral surface of the elastic layer formed on the outer periphery of the shaft core body. It can be formed by forming a coating film of the paint and curing the coating film.

  Examples of the solvent that can be used for the coating material for forming the surface layer containing the polyester copolymer resin, the melamine resin, and the conductive fine particles include methyl ethyl ketone, methyl isobutyl ketone, xylene, and butyl acetate. Moreover, as a method of forming the coating film of the paint on the elastic layer, a coating method such as spraying, dipping, or roll coating can be used. Furthermore, it is also possible to form a surface layer using an inkjet method. And a surface layer can be formed by drying the coating film formed on the elastic layer, removing a solvent, and making it harden | cure. The coating film can be cured by either heating or electron beam irradiation.

  When dip coating is used for the coating film formation, it is preferable to use a liquid circulation type dip coating apparatus having a paint circulation mechanism shown in FIG. The coating apparatus shown in FIG. The immersion tank 5 has a cylindrical shape with an inner diameter slightly larger than the outer diameter of the roller 6 on which the elastic layer 3 is formed and a depth longer than the length of the roller 6 in the axial direction. Installed vertically. An annular liquid receiving portion 7 is provided on the outer periphery of the upper end portion, and the liquid receiving portion 7 is connected to the stirring tank 8 by a pipe 9 connected to the bottom surface. On the other hand, the bottom of the immersion tank 5 is connected to a pump 11 that circulates the surface layer forming paint 10 via a pipe 13. The pump 11 and the stirring tank 8 are connected by a connecting pipe 12. The stirring tank 8 is provided with a stirring blade 14 for stirring the surface layer forming paint 10 accommodated therein. The coating device is provided with a lifting device 15 that lifts and lowers the lifting plate 16 in the axial direction of the immersion bath 5 in the upper part of the immersion bath 5. The roller 6 suspended on the lifting plate 16 can enter and retract into the immersion tank 5. In order to form the surface layer 4 on the elastic layer 3 using such a coating apparatus, the pump 11 is driven and the surface layer forming coating material 10 stored in the stirring tank 8 is passed through the pipes 12 and 13. Supply to the dipping bath 5. The elevating device 15 is driven, the elevating plate 16 is lowered, and the roller 6 is caused to enter the immersion tank 5 filled with the surface layer forming paint 10. The surface layer forming coating material 10 overflowing from the upper end 5 a of the immersion tank due to the entrance of the roller 6 is received by the liquid receiving portion 7 and returned to the stirring tank 8 through the pipe 9. Thereafter, the elevating device is driven to raise the elevating plate, and the roller 6 is retracted from the immersion tank 5 at a predetermined speed to form a coating film on the elastic layer 3. During this time, the stirring blade 14 is rotated in the stirring tank 8 to stir the surface layer forming paint to suppress sedimentation of the contents, and maintain the uniformity of the surface layer forming paint. The roller on which the coating film is formed is removed from the elevating plate 16, and the coating film is dried and cured to form the surface layer 4.

<Shaft core>
The shaft core body used for the conductive member of the present invention supports at least one elastic layer 3 as an upper layer formed on the outer periphery of the shaft core body, has a strength capable of transporting toner to the photoreceptor, and charged toner. As long as it has conductivity that can be an electrode that can be moved to the photoreceptor. Examples of the material include aluminum, stainless steel, conductive synthetic resin, iron, copper alloy, and other metals or alloys.

<Elastic layer>
The elastic layer formed on the outer periphery of the shaft core is a molded body using rubber or resin as a main ingredient. The elastic layer may be a foam or a non-foam. In addition, various rubbers conventionally used for developing rollers can be used as the raw material rubber. Specific examples include the following. Ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), fluorine rubber, Silicone rubber, epichlorohydrin rubber, NBR hydride, polysulfide rubber, urethane rubber. In addition, the raw material resin is mainly a thermoplastic resin, and examples thereof include the following. Polyethylene resins such as low density polyethylene (LDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), and ethylene-vinyl acetate copolymer resin (EVA); polypropylene resins; polycarbonate resins; polystyrene resins ABS resin; polyimide; polyester resin such as polyethylene terephthalate and polybutylene terephthalate; fluororesin; polyamide resin such as polyamide 6, polyamide 66, and MXD6. And these rubber | gum and resin are used individually or in mixture of 2 or more types.

  Furthermore, in the conductive member of the present invention, components such as a conductive agent and a non-conductive filler necessary for the functions required for the elastic layer itself, and various types used when forming rubber and resin molded bodies are used. Additive components such as extenders, antioxidants, processing aids, crosslinking agents, catalysts, dispersion promoters, and the like can be appropriately blended into the raw material main component.

  As the conductive agent, there are an ion conductive material based on an ion conductive mechanism and a conductivity imparting agent based on an electronic conductive mechanism, and either one or a combination thereof can be used.

  Examples of the conductivity-imparting agent based on the electronic conduction mechanism include the following. Powders and fibers of metals such as aluminum, palladium, iron, copper, and silver; metal oxides such as titanium oxide, tin oxide, and zinc oxide; furnace black, acetylene black, ketjen black, PAN-based carbon black, pitch-based carbon Carbon-based conductive agents such as black and carbon nanotubes.

Moreover, the following are mentioned as an ion conductive substance by an ion conductive mechanism. Alkali metal salts such as LiCF ₃ SO ₃ , NaClO ₄ , LiClO ₄ , LiAsF ₆ , LiBF ₄ , NaSCN, KSCN, NaCl; ammonium salts such as NH ₄ Cl, NH ₄ SO ₄ , NH ₄ NO ₃ ; Ca (ClO ₄ ) ₂ , alkaline earth metal salts such as Ba (ClO ₄ ) ₂ ; cationic surfactants such as quaternary ammonium salts; shades such as aliphatic sulfonates, alkyl sulfates, alkyl phosphates Ionic surfactants; amphoteric surfactants such as betaines.

These conductivity-imparting agents can be used alone or in admixture of two or more.
Among these, a carbon black-based conductive agent is preferable because it is relatively inexpensive and easily available, and good conductivity can be imparted regardless of the types of the main rubber and resin material.

As means for dispersing the fine powdered conductive agent in the raw material rubber and resin material, the following means conventionally used may be appropriately used according to the raw material rubber and resin material. For example, means such as a roll kneader and a Banbury mixer can be used. The volume resistivity of the elastic layer is preferably in the range of 1 × 10 ³ to 1 × 10 ¹¹ Ω · cm. When the volume resistivity of the elastic layer is 1 × 10 ³ to 1 × 10 ¹¹ Ω · cm, the toner can be uniformly charged. A more preferable range of the volume resistivity of the elastic layer is 1 × 10 ³ to 1 × 10 ⁸ Ω · cm.

Examples of the filler and extender include the following. Silica, quartz fine powder, diatomaceous earth, zinc oxide, basic magnesium carbonate, activated calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, talc, mica powder, aluminum sulfate, calcium sulfate, barium sulfate, glass fiber, organic Reinforcing agent, organic filler. These fillers may be hydrophobized by treating the surface with an organosilicon compound.
As the antioxidant, known antioxidants used for polymer compounds such as hindered phenolic antioxidants, phenolic antioxidants, phosphorus antioxidants, amine antioxidants, sulfur antioxidants, etc. A thing can be appropriately selected and used.
A known material can be used as the processing aid. Specifically, fatty acids such as stearic acid and oleic acid, metal salts and esters of fatty acids can be used.

  In order to make contact with the photosensitive member to ensure a nip width and to satisfy a suitable setting property, the thickness of the elastic layer is preferably 0.5 mm or more, and more preferably 1. 0.0 mm or more. Further, there is no upper limit on the thickness of the elastic layer as long as the outer diameter accuracy of the conductive member to be manufactured is not impaired. However, if the thickness of the elastic layer is excessively large, leaving the conductive member and the contact member in contact with each other for a long time is not preferable because deformation of the contact portion increases and distortion remains. Therefore, practically, the thickness of the elastic layer is suitably 6.0 mm or less, and more preferably 5.0 mm or less.

  In addition, after the elastic layer is formed, surface treatment such as corona treatment, plasma treatment, flame treatment, and UV treatment can be performed as necessary. By performing these surface treatments, reactive groups are formed on the outermost surface of the elastic layer, and interlayer adhesion with the surface layer can be improved.

In the present invention, the elastic layer can be molded by a conventionally known extrusion molding method, compression molding method, injection molding method, or the like, but is not particularly limited. As long as it has the characteristic described in this invention as a layer structure, it is not limited, It can also be set as the structure of two or more layers.
Note that the conductive member according to the present invention exhibits an excellent effect even when used as a charging member for charging the photoreceptor to a predetermined potential. That is, the conductive member according to the present invention is extremely resistant to surface wear and cracking even when used as a charging member for contact charging over a long period of time in a low-temperature and low-humidity environment where the charging of the photoreceptor is likely to become unstable. It is difficult to occur and contributes to stable charging of the photosensitive member over a long period of time.

<Process cartridge>
Further, as shown in FIG. 4, the process cartridge of the present invention includes at least a conductive member 1, a toner regulating member 21, and a toner container 20, and includes the conductive member 1 as a developing roller to form an electrophotographic image. It is detachably attached to the main body of the apparatus. Further, according to the present invention, a thin layer of toner is formed on the surface of the conductive member, the conductive member is placed in contact with the photosensitive member, and the toner is supplied to the surface of the photosensitive member, whereby the photosensitive member is visible. An electrophotographic image forming apparatus for forming an image. The process cartridge 17 having the conductive member 1, the toner regulating member 21, and the toner container 20 is like the process cartridge detachably mounted on the main body of the electrophotographic image forming apparatus shown in FIG. The blade 26, the waste toner container 25, and the charging roller 24 can be integrated into an all-in-one process cartridge. Further, the conductive member 1 can be used as the charging roller 24.

<Electrophotographic image forming apparatus>
FIG. 5 is a cross-sectional view showing a schematic configuration of an electrophotographic image forming apparatus using a process cartridge having a conductive member of the present invention. The electrophotographic image forming apparatus shown in FIG. 5 includes a developing device 22 including a conductive member 1, a toner supply roller 19, a toner container 20, and a toner regulating member 21, a photoconductor 18, a cleaning blade 26, and a waste toner container. 25 and a charging roller 24, a process cartridge 17 is detachably mounted on the main body of the electrophotographic image forming apparatus. Further, the photoconductor 18, the cleaning blade 26, the waste toner container 25, and the charging roller 24 may be provided in the main body of the electrophotographic image forming apparatus. The photosensitive member 18 rotates in the direction of the arrow, is uniformly charged by a charging roller 24 for charging the photosensitive member 18, and the photosensitive member 18 is exposed to the laser beam 23 as an exposure means for writing an electrostatic latent image on the photosensitive member 18. An electrostatic latent image is formed on the body surface. The electrostatic latent image is developed by applying the toner 20a by the developing device 22 disposed in contact with the photoconductor 18, and visualized as a toner image.

  Development is so-called reversal development in which a toner image is formed on the exposed portion. The visualized toner image on the photoconductor 18 is transferred to a paper 34 as a recording medium by a transfer roller 29 as a transfer member. The paper 34 is fed into the apparatus through a paper feed roller 35 and a suction roller 36, and is transported between the photoconductor 18 and the transfer roller 29 by an endless belt-shaped transfer transport belt 32. The transfer conveyance belt is operated by a driven roller 33, a driving roller 28, and a tension roller 31. A voltage is applied to the transfer roller 29 and the suction roller 36 from a bias power source 30. The paper 34 to which the toner image has been transferred is subjected to fixing processing by the fixing device 27, discharged outside the device, and the printing operation is completed.

  On the other hand, the untransferred toner remaining on the photosensitive member 18 without being transferred is scraped off by a cleaning blade 26 which is a cleaning member for cleaning the surface of the photosensitive member, and is stored in a waste toner container 25 and cleaned. The body 18 repeats the above process.

  The developing device 22 includes a developing container 20 containing toner 20a as a one-component developer, and a conductive material as a toner carrier that is located in an opening extending in the longitudinal direction in the developing container and is opposed to the photosensitive member 18. The electrostatic latent image on the photosensitive member 18 is developed and visualized.

  Further, as the toner regulating member 21, a member in which a rubber elastic body is fixed to a metal sheet metal, a member having a spring property such as a thin plate of SUS or phosphor bronze, or a member in which resin or rubber is laminated on the surface thereof is used. It is done. Further, by applying a voltage higher than the voltage applied to the conductive member 1 to the toner regulating member 21, the toner layer on the conductive member can be controlled. It is preferable to use a thin plate of SUS or phosphor bronze. A voltage is applied from the bias power source 30 to the conductive member 1 and the toner regulating member 21, but the voltage applied to the developing blade 21 is 100 V in absolute value with respect to the voltage applied to the conductive member 1. It is preferable that the voltage be 300V larger.

  The developing process in the developing device 22 will be described below. The toner is applied onto the conductive member 1 by the toner supply roller 19 that is rotatably supported. The toner applied on the conductive member 1 is rubbed against the toner regulating member 21 by the rotation of the conductive member 1. Here, the toner on the conductive member is uniformly coated on the conductive member by the bias applied to the toner regulating member 21. The conductive member 1 is in contact with the photosensitive member 18 while rotating, and an image is formed by developing the electrostatic latent image formed on the photosensitive member 18 with toner coated on the conductive member 1. .

  As the structure of the toner supply roller 19, a foamed skeleton-like sponge structure or a fur brush structure in which fibers such as rayon and polyamide are planted on the shaft core is used to supply the toner 20 a to the conductive member 1 and undeveloped toner. It is preferable from the point of peeling off. In this embodiment, an elastic roller having a polyurethane foam on a shaft core was used.

  The contact width of the toner supply roller 19 with respect to the conductive member 1 is preferably 1 to 8 mm, and it is preferable that the conductive member 1 has a relative speed at the contact portion.

  Hereinafter, the conductive member, the process cartridge, and the electrophotographic image forming apparatus of the present invention will be described in detail, but the technical scope of the present invention is not limited thereto. First, a method for producing an elastic layer roller in Examples and Comparative Examples of the present invention will be specifically illustrated and described.

<Preparation of elastic layer roller (1)>
The following materials were kneaded using a twin screw extruder having a diameter of 30 mm and L / D32, and extruded to prepare a resin mixture.

Styrene butadiene elastomer (trade name: SL563, manufactured by JSR Corporation): 100 parts by mass Carbon black (trade name: Printex U, manufactured by Evonik Degussa Japan): 40 parts by mass Calcium carbonate (trade name: Nanox # 30, Maruo Calcium Co., Ltd.): 60 parts by mass, zinc oxide (trade name: activated zinc white, produced by Sakai Chemical Industry Co., Ltd.): 5 parts by mass, zinc stearate (trade name: SZ-P, Sakai Chemical Industry Co., Ltd.) 2) parts by mass / vulcanization accelerator 1 (trade name Noxeller M, manufactured by Ouchi Shinsei): 0.5 parts by mass / vulcanization accelerator 2 (trade name Noxeller TRA, manufactured by Ouchi Shinsei): 1.2 parts by mass / sulfur (trade name: Sulfax PMC, manufactured by Tsurumi Chemical Co., Ltd.): 1.6 parts by mass

  The resin mixture was then pelletized. This pellet was extruded on a stainless steel (SUS304) shaft core having a diameter of 6 mm and a length of 250 mm using a crosshead extruder to form an elastic layer. An elastic layer roller having an elastic layer having a thickness of 3 mm (diameter: 12 mm) around the shaft core by cutting the end of the elastic layer and further polishing the surface portion of the elastic layer with a rotating grindstone (GC # 80) (1) was obtained.

<Preparation of elastic layer roller (2)>
An unvulcanized silicone rubber prepared by mixing a liquid silicone rubber base material A having the following vinyl groups as a reactive group and a liquid silicone rubber base material B having vinyl groups and SiH groups in a mass ratio of 1: 1. The elastic layer roller (2) was produced by thermosetting.

(Liquid silicone rubber base material A having vinyl group)
Dimethylpolysiloxane having vinyl groups at both ends and having a weight average molecular weight (Mw) of 85000: 100 parts by mass Carbon black (trade name: Raven 860 Ultra, manufactured by Columbian Chemical): 8 parts by mass Silica (trade name: Leolosil MT -10, manufactured by Tokuyama Corporation): 10 parts by mass

(Liquid silicone rubber base material B having vinyl group and SiH group)
Dimethylpolysiloxane having vinyl groups at both ends and having a weight average molecular weight (Mw) of 85000: 100 parts by mass Carbon black (trade name: Raven 860 Ultra, manufactured by Columbian Chemical): 8 parts by mass Silica (trade name: Leolosil MT -10, manufactured by Tokuyama Corporation): 10 parts by mass / curing catalyst (2% by mass of an isopropanol solution of chloroplatinic acid mixed with 10 ppm with respect to dimethylpolysiloxane): 0.5 parts by mass / methyl hydrogen polysiloxane: 3 parts by mass (amount of SiH groups of 1.1 mol with respect to 1 mol of vinyl groups contained in base materials A and B)

  As a shaft core body, a primer (trade name: DY35-051, manufactured by Toray Dow Corning Co., Ltd.) is applied to a 6 mm diameter core bar made of SUS304 to a thickness of about 1 μm and baked at 150 ° C. for 30 minutes. Was used. Next, the shaft core was placed in a mold, and the unvulcanized silicone rubber was injected into a cavity formed in the mold. Subsequently, the mold was heated to cure and cure the unvulcanized silicone rubber at 150 ° C. for 15 minutes, and then demolded after cooling. Thereafter, the mixture was further heated at 180 ° C. for 1 hour to complete the curing reaction, whereby an elastic layer roller (2) having an elastic layer having a thickness of 3 mm around the shaft core was obtained.

  Subsequently, the synthesis of the (aliphatic) ester resin which is a starting material of the polyester copolymer resin in Examples and Comparative Examples of the present invention was performed using the following starting materials. Hereinafter, specific synthesis methods will be exemplified and described, but the present invention is not limited thereto.

<Ester resin raw material / aliphatic diols (B-1)>
・ 1,2-ethanediol (R ₁ carbon number: 2, manufactured by Sankyo Chemical Co., Ltd.)
1,4-butanediol (R ₁ carbon number: 4, Sankyo Chemical Co., Ltd.)
・ 1,5-pentanediol (R ₁ carbon number: 5, manufactured by Ube Industries, Ltd.)
・ 1,6-hexanediol (R ₁ carbon number: 6, manufactured by Ube Industries, Ltd.)
・ 1,7-Heptanediol (R ₁ carbon number: 7, manufactured by Ube Industries, Ltd.)
・ 1,9-nonanediol (R ₁ carbon number: 9, manufactured by Merck Chemicals Japan)
・ 3-methyl 1,5-pentanediol (R ₁ carbon number: 6, branched type, manufactured by Kuraray Co., Ltd.)
2-methyl 1,8-octanediol (R ₁ carbon number: 9, branched type, manufactured by Kuraray Co., Ltd.)
・ 1,10-decanediol (R ₁ carbon number: 10, Tokyo Chemical Industry Co., Ltd.)

<Ester resin raw material / dicarboxylic acid (B-2)>
Adipic acid (aliphatic, R ₂ carbon number: 4, manufactured by Sumitomo Chemical Co., Ltd.)
-Sebacic acid (aliphatic, R ₂ carbon number: 8, manufactured by KE Trading Co., Ltd.)
・ Terephthalic acid (aromatic, manufactured by Mitsui Chemicals, Inc.)

[Synthesis of ester resin (1)]
620.6 g (10 mol) of 1,2-ethanediol, 730.7 g (10 mol) of adipic acid, and 0.94 g (0.50 mol) of catalyst tetrabutyl titanate were placed in a Pyrex (registered trademark) glass flask and a magnetic stirrer. Were mixed and stirred. Then, it heated until the temperature in a flask was set to 230 degreeC, and mixed and stirred for 30 minutes. The final pressure was 30 Torr, and water distilled off was excluded from the reaction system. After completion of the reaction, an ester resin (1) was obtained as a white reaction product. This ester resin (1) was dissolved in chloroform and then reprecipitated with methanol, and then the obtained product was subjected to spectral analysis using FT-IR and H-NMR. As a result, it was confirmed that the ester resin (1) is an aliphatic polyester having ethyl adipate as a basic skeleton. The starting materials and structures used for the synthesis are shown in Table 1.

[Synthesis of ester resins (2) to (11)]
The ester resins (2) to (11) were synthesized in the same manner as the ester resin (1). At this time, the molar ratio of aliphatic diols to dibasic acid was always 1: 1. The starting materials and structures used for the synthesis are shown in Table 1.

[Synthesis of Ester Resin (12)]
ε-Caprolactone (manufactured by Daicel Industries, Ltd.) 1141.4 g (10 mol), ethylene glycol (manufactured by Mitsubishi Chemical Corporation) 620.6 g (10 mol), sodium methylate 0.50 g as an initiator is made of Pyrex (registered trademark) glass It put into the flask and mixed and stirred for 10 minutes using the magnetic stirrer. Then, it heated until the temperature in a flask was set to 100 degreeC, and mixed and stirred for 30 minutes. The final pressure was 10 Torr, and the distilled water was excluded from the reaction system. After completion of the reaction, an ester resin (12) was obtained as a white reaction product. This ester resin (12) was dissolved in chloroform and then reprecipitated with methanol, and then the obtained product was subjected to spectral analysis using FT-IR and H-NMR. As a result, it was confirmed that the ester resin (12) was an aliphatic polyester having R ₁ having 5 carbon atoms and R ₂ having 2 carbon atoms as a basic skeleton.

  Then, the polyester copolymer resin in the Example and comparative example of this invention was synthesize | combined. Hereinafter, specific synthesis methods will be exemplified and described, but the present invention is not limited thereto.

[Synthesis of polyester copolymer resin (1)]
The ester resin (1) obtained by the above method was dried at 50 ° C. under a reduced pressure of 0.1 mmHg for 36 hours. Thereafter, 800 parts by mass of polyethylene terephthalate (trade name: resin for polyethylene terephthalate film, manufactured by Echizen Polymer Co., Ltd.) and 0.1 part by mass of tetrabutyl titanate were placed in a Pyrex (registered trademark) glass flask, and ester resin (1 ) 200 parts by mass were charged in a nitrogen atmosphere. Thereafter, the pressure reduction was started immediately and the degree of pressure reduction was 0.15 mmHg in 30 minutes. This mixture was polycondensed at a temperature of 245 ° C. for 30 minutes, and then collected in a strand form into water and cooled to obtain a product. The obtained product was subjected to spectral analysis using FT-IR and H-NMR. As a result, the product has a segment of the chemical formula (A), and in the segment of the chemical formula (B), a polyester copolymer resin in which R ₁ has 2 carbon atoms and R ₂ has 4 carbon atoms as a basic skeleton. It was confirmed that. The raw materials and structure of the synthesized PET-E- (1) are shown in Table 2.

[Synthesis of polyester copolymer resins (2) to (12)]
The polyester copolymer resins (2) to (12) were synthesized in the same manner as the polyester copolymer resin (1). Table 2 shows the raw materials and structures of the synthesized PET-E- (2) to (12).

  Subsequently, the surface layer forming coating liquid in the examples and comparative examples of the present invention is composed of the polyester copolymer resin synthesized earlier, the following polyester polyol, melamine resin, benzoguanamine resin, isocyanate and conductive fine particles. Prepared using starting material.

<Polyester polyol>
Ester polyol (trade name: P-3010, consisting of 3-methyl-1,5-pentanediol and adipic acid. SP value: 8.4, manufactured by Kuraray Co., Ltd.)

<Melamine resin>
-N-Butylated melamine resin (trade name: Uban 20SB, SP value: 7.4, Mn: 6500, manufactured by Mitsui Chemicals, Inc.)
-N-Butylated melamine resin (trade name: Uban 21R, SP value: 8.3, Mn: 10,000, manufactured by Mitsui Chemicals, Inc.)
-N-Butylated melamine resin (trade name: Uban 2020, SP value: 7.8, Mn: 2500, manufactured by Mitsui Chemicals, Inc.)
・ Methylated melamine resin (trade name: SB15-594, SP value: 8.2, Mn: 2000, manufactured by DIC Corporation)
・ Methylated melamine resin (trade name: Cymel 303, SP value: 8.4, Mn: 500, manufactured by Mitsui Cytec)
・ Isobutyl-modified melamine resin (trade name: 265B-L, SP value: 7.7, Mn: 6500, manufactured by Hitachi Chemical Co., Ltd.)

<Benzoguanamine resin>
Dimethylimino type benzoguanamine resin (trade name: Mycoat 106, SP value: 8.9, Mn: 1000, manufactured by Mitsui Cytec)

<Isocyanate resin>
Block type isocyanate resin (trade name: Coronate 2507, SP value: 8.8, Mn: 1500, manufactured by Nippon Polyurethane Industry Co., Ltd.)

<Conductive fine particles>
Acidic carbon (trade name: MA-100, average primary particle size: 22 nm, DBP absorption: 100 ml / 100 g, pH: 3.5, manufactured by Mitsubishi Chemical Corporation)
Acidic carbon (trade name: MA-11, average primary particle size: 29 nm, DBP absorption: 64 ml / 100 g, pH: 3.5, manufactured by Mitsubishi Chemical Corporation)
-Tin oxide conductive powder (trade name: S-2000, DBP absorption amount: 60 ml / 100 g, pH: 4.0, manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.)

  In addition, although the preparation method of the coating liquid for surface layer formation is illustrated and demonstrated concretely below, this invention is not limited to these.

[Preparation of surface layer forming coating liquid (1)]
PET-E- (1): 80 parts by mass n-Butylated melamine resin (trade name: Uban 2020): 20 parts by mass As a material for the surface layer forming coating liquid, the above components are mixed to form a surface layer resin component It was. First, PET-E- (1) was adjusted to 50% resin solids using methyl ethyl ketone (MEK) and stirred until it was completely dissolved. Then, n-butylated melamine resin was added and mixed and stirred. Subsequently, 30 parts by mass of carbon black (trade name: MA-100, manufactured by Mitsui Chemicals, Inc.) and MEK were added to 100 parts by mass of the solid content of the surface layer resin component, and the mixture was stirred with an electric motor for 1 hour. Subsequently, MEK was further added so that the total solid content ratio was 25% by mass, and the mixture was further stirred for 1 hour with a motor. Subsequently, the above mixed solution was uniformly dispersed with a horizontal dispersion NVM-03 (trade name, manufactured by IMEX) under conditions of a peripheral speed of 7 m / sec, a flow rate of 1 cc / min, and a dispersion temperature of 15 ° C. for 3 hours. In this dispersion, glass beads having a diameter of 1.5 mm (trade name: DMB503B, manufactured by Hotters Ballotinis) were used. Next, this solution is diluted to a solid content of 18% by mass with MEK so that the film thickness after forming the surface layer becomes 10 μm, and this solution is filtered through a 300 mesh screen to obtain a coating material for forming the surface layer. (1).

[Preparation of surface layer forming coating liquids (2) to (60)]
The surface layer forming coating liquids (2) to (60) were prepared in the same manner as the surface layer forming coating liquid (1) except that the starting materials shown in Tables 3 and 4 were used. Tables 3 and 4 show the parts by mass and physical properties of the starting materials used in the preparation of each surface layer forming coating liquid. In addition, in the description in the table | surface of this invention, a polyester copolymer resin and a polyester polyol are called a main ingredient. Melamine resins, benzoguanamine resins, and isocyanate resins are referred to as curing agents.

  Then, the measuring method of the number average molecular weight (Mn) and SP value of the resin raw material of the surface layer of the Example of this invention and a comparative example, and the analysis method of electroconductive fine particles are demonstrated below.

[Method for measuring number average molecular weight (Mn) of resin raw material]
(Mn measurement of melamine resin by GPC)
A high-performance liquid chromatograph analyzer “HLC-8120GPC” (trade name, manufactured by Tosoh Corporation) in which two GPC columns “TSKgel SuperHM-M” (trade name, manufactured by Tosoh Corporation) were connected in series was used. The measurement sample was measured as a 0.1 mass% THF solution under the measurement conditions of tetrahydrofuran (THF) as a solvent, temperature 40 ° C., flow rate 0.6 ml / min, RI (refractive index) detector. A calibration curve was created using several types of monodisperse standard polystyrene (manufactured by Tosoh Corporation) as a standard sample for creating a calibration curve, and the number average molecular weight (Mn) was determined from the retention time of the measurement sample obtained based on this calibration curve. ) Tables 3 and 4 show the results of the conductive roller as the conductive member produced in each example and comparative example.

[Measurement of SP value of resin raw material]
The SP values of the polyester copolymer resin and melamine resin were measured as follows.
0.25 g of the sample from which the solvent was completely volatilized was placed in a 30 ml sample tube, and 3.0 ml of acetone was added as a good solvent, and the mixture was sufficiently stirred and dissolved. Next, normal hexane was dropped as a poor solvent using a 50 ml burette, and the amount of dripping required to produce white turbidity was measured. The SP value (δ) was calculated by the following formula from the SP value of each solvent and the volume fraction of normal hexane required to generate acetone and white turbidity required for dissolution of the sample.
δ = δ _Acetone × φ _Acetone + δ _Hexane × φ _Hexane
φ _Acetone = V _Acetone / (V _Acetone + V _Hexane )
φ _Hexane = V _Hexane / (V _Acetone + V _Hexane )

δ _Acetone : SP value of acetone (10.0)
δ _Hexane : SP value of normal hexane (7.0)
φ _Acetone : Volume fraction of acetone φ _Hexane : Volume fraction of normal hexane V _Acetone : _Acetone amount required for dissolution of sample (3.0 ml)
V _Hexane : The amount of normal hexane dripping required to produce white turbidity (measured value)

[Analytical method of conductive fine particles]
(Measurement of conductive fine particle content)
An appropriate amount of the surface layer of the conductive roller was cut out from the elastic layer using a manipulator. Thereafter, the content of conductive fine particles was measured using thermogravimetric analysis (DTA-TG) under the following conditions. At this time, the material whose weight is reduced by the heat treatment under a nitrogen atmosphere corresponds to the one derived from the surface layer resin. In addition, a material whose weight is reduced by heat treatment in an oxygen atmosphere corresponds to a material derived from conductive fine particles. From the quantitative relationship, the content of conductive fine particles contained in the surface layer of the present invention was determined. Tables 3 and 4 show the content of conductive fine particles in the conductive rollers prepared in each of the examples and comparative examples.

[Measurement condition]
・ Measuring instrument: Thermo plus TG8120 (trade name; manufactured by Rigaku Corporation)
Temperature rise / fall conditions: 25 ° C. → 800 ° C. → 200 ° C. (under nitrogen atmosphere) → 800 ° C. (under oxygen atmosphere)
・ Temperature increase / decrease rate condition: 10 ° C./min
・ Sample holder for measurement; Alumina pan

(Measurement of average primary particle size of conductive fine particles)
An appropriate amount of the surface layer of the conductive roller was cut out from the elastic layer using a manipulator, and then the matrix phase polymer was decomposed under baking conditions at 500 ° C. for 24 hours. Thereafter, the residue was washed to collect the conductive fine particles in the surface layer. About 0.1 g of the conductive fine particles were weighed into a 30 cc glass bottle, then 20 ml of toluene was added and the mixture was covered, and uniformly dispersed using an ultrasonic vibrator for 15 minutes. Then, the sample for evaluation was produced by sucking a dispersion liquid using a dropper, dripping 1 drop on a glass plate, and drying. The sample for evaluation was observed using a scanning microscope S-4800 (trade name, manufactured by Hitachi Kogyo Co., Ltd.) and defined as the average primary particle diameter of each conductive fine particle by using the intercept method.

(Measurement of DBP absorption of conductive fine particles)
The DBP absorption amount of the conductive fine particles used for forming the surface layer of the present invention was measured by a method based on JIS-Z8901.

(Measurement of pH of conductive fine particles)
10 g of each conductive fine particle was weighed into a beaker, 3 drops of 100 ml of water and ethyl alcohol were added, covered with a watch glass, and boiled for 15 minutes. After boiling, the mixture was cooled to room temperature, the supernatant was removed by a centrifugal separation method, and a muddy measurement sample was prepared. In this measurement sample, an electrode of a pH meter “HM-30R” (trade name, manufactured by Toa DKK Co., Ltd.) is placed and measured while moving in a beaker. The value at which the pH value becomes constant is determined for each conductive fine particle. The pH value was used.

(Example 1)
First, excimer UV treatment was performed on the elastic layer roller (1) produced previously to perform surface treatment. While rotating the shaft core of the elastic layer roller (1) at 30 rpm as a rotation axis, ultraviolet light having a wavelength of 172 nm is irradiated by a capillary excimer lamp (manufactured by Harrison Toshiba Lighting) so that the integrated light amount becomes 150 mJ / cm ^2. Processed. The distance between the elastic layer surface and the excimer lamp at the time of irradiation was 2 mm. Thereafter, the surface layer-forming coating liquid (1) prepared above was applied to the peripheral surface of the surface-treated elastic layer roller by a dipping coating method to form an outermost surface layer.

  This surface layer was formed using the dip coating apparatus shown in FIG. 250 cc of the surface layer forming coating liquid (1) maintained at a liquid temperature of 23 ° C. was poured from below the immersion tank 5 (cylinder) having an inner diameter of 32 mm and a length of 300 mm, and overflowed from the upper end of the immersion tank 5. The liquid was circulated again below the immersion tank 5. The elastic layer roller (1) is immersed in the immersion tank 5 at an intrusion speed of 100 mm / s and stopped for 10 seconds, and then the elastic layer roller (1) under the conditions of an initial speed of 300 mm / s and an final speed of 200 mm / s. ) Was pulled up and allowed to air dry for 60 minutes. Subsequently, the raw material of the surface layer was cured by heat treatment at 140 ° C. for 2 hours, and the conductive roller (1) of Example 1 was produced. In addition, the film thickness of the produced surface layer was 10 μm.

In order to identify the matrix phase and the domain phase in the surface layer of the obtained conductive roller (1), mapping by Fourier transform-infrared absorption (FT-IR) method was performed. For mapping, an infrared microscope / imaging system (trade names: Spectrum 400 (analyzer) and Spotlight 400 (scanner), manufactured by PerkinElmer) was used. The measurement was performed using an ATR imaging accessory under the conditions of pixel size: 1.56 μm, resolution: 16 cm ⁻¹ , field of view: 300 μm × 300 μm, and scanning speed of 1.0 cm / s. A thin slice of the surface layer was cut out from the conductive roller (1) with a microtome and mapped. As a result, a spectrum due to the ester group (1200 cm ⁻¹ ) was confirmed over the entire surface layer. In addition, regions where the spectrum due to ester groups and phenyl groups (1500 cm ⁻¹ , 1610 cm ⁻¹ ) are relatively high compared to the surroundings are dotted with a circle equivalent diameter of about 10 to 100 μm. It was confirmed that In the area surrounding the interspersed section, the spectrum of the resulting amino group (3070,3280cm ^-1) and ether groups (1100 cm ^-1) is compared with the interspersed section, it was confirmed extremely high .

Further, the domain-like region having a low spectrum due to the amino group and ether group was further cut out with a microtome, dissolved in MEK, and purified and recrystallized. Then, when the recrystallized substance was analyzed using the H-NMR method, the segment of Chemical formula (A) and Chemical formula (B) was confirmed. Moreover, it was identified that the carbon number of R ₁ in the chemical formula (B) is 2, and the carbon number of R ₂ is 4. On the other hand, since the site | part of the area | region where the spectrum of both ester group and amino group origin was strong could not be melt | dissolved in MEK, it analyzed using pyrolysis GC-MS. As a result, segments of chemical formulas (A), (B) and (C) were confirmed. Moreover, the butylene ether group considered to originate from the chain extension part of a melamine resin was confirmed.

  Therefore, it was identified that the matrix phase of the conductive roller (1) is a polyester melamine resin derived from the chemical formulas (A), (B) and (C). Furthermore, the domain phase was identified to be a polyester copolymer resin containing chemical formulas (A) and (B) showing thermoplasticity from the solubility in a solvent and the results of H-NMR. In the present invention, the domain phase can be identified by a scanning electron microscope (SEM) or a scanning transmission electron microscope (STEM).

  Subsequently, the uneven distribution of the conductive fine particles in the matrix phase was confirmed by performing mapping analysis with a scanning probe microscope (SPM). As a result, the domain-like region showed insulation, while the surrounding matrix region was confirmed to be conductive. Furthermore, the domain-like region and the matrix-like region were each cut out with a microtome and analyzed using the thermogravimetric analysis method (DTA-TG) described above. As a result, in the domain-like region, almost no exothermic peak derived from carbon black was confirmed in the analysis under an oxygen atmosphere. Therefore, the domain phase of the conductive roller (1) contained almost no conductive fine particles, and the uneven distribution of the conductive fine particles in the matrix phase was confirmed.

  Further, image evaluation was performed by forming an image with an electrophotographic image forming apparatus (laser printer described later) equipped with the conductive roller (1) as a developing roller. Table 9 shows the results of evaluation of the surface layer characteristics and image evaluation of this conductive roller (1).

(Examples 2-51)
In Example 1, the elastic layer roller (1) is changed to the elastic layer roller (2), or the surface layer forming coating liquids (2) to (51) are used instead of the surface layer forming coating liquid (1). Otherwise, conductive rollers (2) to (51) were produced in the same manner as in Example 1. As with the conductive roller (1) of Example 1, the conductive rollers (2) to (51) were subjected to surface layer structural analysis, phase separation structure confirmation, and conductive distribution analysis. Further, images were formed using the conductive rollers (2) to (51) as developing rollers, and image evaluation was performed. Table 9 shows the results of the elastic layer roller, surface layer property evaluation and image evaluation used in the conductive rollers (2) to (51) in Examples 2 to 51.

(Comparative Examples 1-9)
In Example 1, the elastic layer roller (1) is changed to the elastic layer roller (2), or the surface layer forming coating liquids (52) to (60) are used instead of the surface layer forming coating liquid (1). Otherwise, conductive rollers (52) to (60) were produced in the same manner as in Example 1. The conductive rollers (52) to (60) were subjected to surface layer structural analysis, phase separation structure confirmation, and conductive distribution analysis in the same manner as the conductive roller (1) of Example 1. Further, images were formed using the conductive rollers (52) to (60) as developing rollers, and image evaluation was performed. Table 10 shows the elastic layer rollers used for the conductive rollers (52) to (60) in Comparative Examples 1 to 9, the evaluation of the surface layer characteristics, and the image evaluation results.

<Evaluation 1: Evaluation as a developing roller>
Subsequently, the image evaluation methods performed in the examples and comparative examples of the present invention will be specifically described below.
The laser printer used for the image evaluation of the present invention is one obtained by modifying the output speed of the recording medium of a commercially available laser printer (trade name: HP Color LaserJET CP4525dn, manufactured by Hured Packard) to 60 ppm. Remodeling was performed by adjusting the settings of the high-voltage power supply, motor gear, and paper transport as appropriate. Further, the toner carrying amount on the conductive roller was adjusted to 0.50 mg / cm ² by changing the fixing position of the developing blade or by inserting a spacer between the developing blade and the process cartridge container.

[Image evaluation of fog after long-term storage in high temperature and high humidity environment]
The manufactured new conductive roller is incorporated as a developing roller into a new process cartridge (trade name: CE260X, manufactured by Hured Packard, color: black), and this process cartridge is placed in an environment with a temperature of 35 ° C. and a humidity of 85% RH. Left for 48 hours. Then, in the same environment, the process cartridge was installed in the laser printer remodeling machine, and 12,000 continuous images were output at a printing rate of 1%. Thereafter, a white solid image was output in the same environment. Using a reflection densitometer (trade name: TC-6DS / A, manufactured by Tokyo Denshoku Co., Ltd.), the reflectance of the solid white portion of the non-printing range (reference) and the printing range is measured, and the amount of decrease in reflectance relative to the reference ( %) Was “fog”. This fog was evaluated according to the criteria shown in Table 5 below. Tables 9 and 10 show the results of the conductive rollers produced in each example and comparative example.

[Image evaluation of image followability]
After the above image evaluation of fog after long-term storage in a high-temperature, high-humidity environment, 100 images are output continuously at a printing rate of 1% in the same environment, and then 5 continuous black images of A4 size (210 mm x 297 mm) are output. did. When the toner transportability of the conductive roller is lowered, when a black solid image that requires a large amount of toner supply to the photoconductor is continuously output, a significant difference in density occurs between the leading edge and the trailing edge of the output image. The density located at the front end 50 mm and the rear end 50 mm (247 mm from the front end) of this continuous output image is measured using the reflection densitometer, and the density reduction rate at the rear end with respect to the front end is an index of “image followability”. It was. This image followability was evaluated according to the criteria shown in Table 6 below. Tables 9 and 10 show the results of the conductive rollers produced in each example and comparative example.

[Evaluation of toner fusion in low temperature and low humidity environment]
The manufactured new conductive roller was incorporated into a new process cartridge (trade name: CE263A, manufactured by Hured Packard, color: magenta), and the process cartridge was left in an environment of temperature 15 ° C. and humidity 10% RH for 48 hours. . Then, in the same environment, the process cartridge was installed in the laser printer remodeling machine, and continuous image output was performed at a printing rate of 2%. When the toner is fused to the surface of the conductive roller, the toner becomes fogged due to a decrease in the triboelectric chargeability imparted to the toner, and appears on the image. Therefore, in the evaluation of toner fusion in a low temperature and low humidity environment, the number of output sheets in which fog exceeding 3% is observed in the solid white portion is measured, and the roller appearance after image evaluation is evaluated according to the evaluation criteria shown in Table 7 below. I went there. Further, the reflectance of the solid white portion of the non-printing range (reference) and the printing range was measured using the above reflection densitometer for every 1000 outputs. The amount of decrease in reflectance (%) relative to the reference was defined as “fogging”. Further, even when noticeable fogging or toner fusion occurred, the toner fusion evaluation was continued until the number of continuous prints reached 15,000. Prior to the observation of the roller appearance, the appearance evaluation was performed according to the criteria shown in Table 7 below by removing the toner that does not contribute to toner fusion by air blow. Tables 9 and 10 show the results of the conductive rollers produced in each example and comparative example.

[Evaluation of wear resistance and crack resistance]
Simultaneously with the toner fusion evaluation in the low-temperature and low-humidity environment described above, the surface layer of the conductive roller is observed with a digital microscope (trade name: VH-8000; manufactured by Keyence Corporation) for every 5000 image outputs, and is resistant to abrasion. The evaluation of the property and crack resistance was evaluated according to the criteria shown in Table 8 below. Tables 9 and 10 show the results of the conductive rollers produced in each example and comparative example.

  As shown in Table 9, the conductive roller according to the present invention has (1) fog in a high temperature and high humidity environment (2) solid image following failure (3) toner fusion in a low temperature and low humidity environment (4) abrasion resistance And crack resistance can be effectively suppressed. In particular, in Examples (23), (24), (26), (35), (46) and (47), it is clear that the above-mentioned image damage can be suppressed at a high level.

On the other hand, the conductive rollers (52) and (53) in Comparative Examples (1) and (2) do not contain the chemical formula (A) derived from the PET resin in the surface layer, and thus are presumed to be due to high charge attenuation. Remarkable fogging in a high temperature and high humidity environment was confirmed. Furthermore, since the phase separation structure was not confirmed, a remarkable solid image following failure that was presumed to be caused by insufficient toner attractive force due to electric field gradient force was confirmed. Since the conductive roller (54) in the comparative example (3) does not contain the chemical formula (C) that is flexible in molecular structure in the surface layer, the flexibility is not expressed, and remarkable shaving or Cracks were confirmed. Further, remarkable toner fusing was confirmed starting from scraping or cracking of the surface layer. Furthermore, since the phase separation structure was not confirmed, a remarkable image following failure was confirmed. Since the conductive roller (55) in Comparative Example (4) contains an aromatic ester that is molecularly rigid and highly crystalline in the chemical formula (B), flexibility cannot be obtained. Remarkable shaving and cracking were confirmed. Further, remarkable toner fusing was confirmed starting from scraping or cracking of the surface layer. The conductive roller (56) in Comparative Example (5) is sufficiently long because the alkyl chain length (R ₁ carbon number) in the chemical formula (B) is too long, and thus the crystallinity is strong and the crystal size is excessive. The flexibility was not obtained, and remarkable shaving and cracking were confirmed through image output. Further, remarkable toner fusing was confirmed starting from an excessively precipitated crystal phase. Since the conductive rollers (57) and (58) in Comparative Examples (6) and (7) contain a very rigid benzoguanamine resin in terms of molecular structure in the surface layer, the flexibility is poor, and through the image output Remarkable scraping and cracking were confirmed. Further, remarkable toner fusing was confirmed starting from scraping or cracking of the surface layer. Furthermore, in the conductive roller in Comparative Example (7), it was confirmed that the phase separation structure was formed and the conductive fine particles were unevenly distributed in the matrix phase by the combination of the benzoguanamine resin and the polyester copolymer resin both having high polarity. Was not. As a result, the toner attractive force due to the contribution of the electric field gradient force did not appear, and a remarkable image following failure was confirmed. Since the conductive roller (59) in the comparative example (8) uses a relatively high-polarity isocyanate resin instead of the melamine resin of the chemical formula (C), formation of a phase separation structure and conductive fine particles to the matrix phase The uneven distribution of was not confirmed. As a result, the toner attractive force due to the contribution of the electric field gradient force did not appear, and a remarkable image following failure was confirmed. Since the conductive roller (60) in Comparative Example (9) does not contain conductive fine particles in the surface layer and the matrix phase, toner attracting force due to electric field gradient force cannot be obtained, and remarkable image following failure is confirmed. It was done. Furthermore, since the entire surface layer showed insulating properties, the electrostatic adhesion increased excessively, and remarkable toner fusion was confirmed in a low temperature and low humidity environment.

(Examples 52 to 55)
The elastic layer roller (1) produced above was polished using a rotating grindstone (GC # 80) to form an elastic layer having a thickness of 1.25 mm (diameter: 8.5 mm). Then, the elastic layer roller (3) was obtained by processing a shaft core so that it could be rearranged as a charging roller of a laser printer (trade name: HP Color LaserJET CP4525dn, manufactured by Hured Packard). A surface layer is formed on the elastic layer roller (3) using the surface layer forming coating liquids (23), (24), (26) and (35) in the same manner as in Example (1). Conductive rollers (61) to (64) of (52) to (55) were obtained.

(Comparative Examples 10-12)
On the elastic layer roller (3) produced above, the surface layer was formed using the surface layer forming coating liquids (54), (58) and (60) as in Example (1). Conductive rollers (65) to (67) of Examples (10) to (12) were obtained.

<Evaluation 2: Evaluation as a charging roller>
The produced new conductive rollers (61) to (67) are assembled as a charging roller in a new process cartridge (trade name: CE260X, manufactured by Hured Packard, color: black). The sample was left in an environment of 10% RH for 48 hours. In the same environment, each process cartridge was loaded into the modified laser printer used in Evaluation 1, and 15000 electrophotographic images were continuously output at a printing rate of 2%. Subsequently, one halftone image was output, the halftone image was visually observed, and image unevenness due to uneven charging on the photoreceptor was evaluated according to the following criteria. Table 11 shows the results of the conductive rollers produced in each of the examples and comparative examples.

A: Image unevenness due to uneven charging on the photoconductor was not recognized.
B: Image unevenness due to uneven charging on the photoreceptor was observed.

  Furthermore, in the same manner as the conductive rollers (1) to (60), the abrasion resistance and crack resistance were evaluated.

  As a result, in the image incorporating the conductive rollers (61) to (64), no streak-like image unevenness due to uneven charging on the photoconductor was confirmed. Further, even after 15000 sheets of continuous printing, no defects such as scraping or cracking of the surface layer were confirmed. This is presumably because it was possible to maintain uniform chargeability to the photoreceptor by suppressing surface layer scraping and cracking through continuous image output.

  Further, in the conductive rollers (65) and (66), noticeable image unevenness due to uneven charging was confirmed. Further, after 15000 sheets of continuous printing, defects such as remarkable shaving and cracking were confirmed in the surface layer. Further, in the conductive roller (67), defects such as remarkable shaving and cracking could not be confirmed, but image unevenness due to significant charging unevenness was confirmed.

  Table 11 shows the results of the elastic layer roller used for the conductive rollers (61) to (67), the surface layer-forming paint, the evaluation of the surface layer characteristics, and the image evaluation.

  As described above, the conductive roller produced in these examples of the present invention could be suitably used as a developing roller and a charging roller.

1 Conductive roller (developing roller)
2 Shaft core 3 Elastic layer 4 Surface layer 4a Matrix phase 4b Domain phase 4c Conductive fine particles 5 Immersion tank 5a Upper end of immersion tank 6 Roller 7 Liquid receiving part 8 Stir tank 9 Tube 10 Surface layer forming paint 11 Pumps 12, 13 Tube 14 Stirring blade 15 Lifting device 16 Lifting plate 17 Process cartridge 18 Photoconductor 19 Toner supply roller 20 Toner container 20a Toner 21 Toner regulating member 22 Developing device 23 Laser beam 24 Charging roller (conductive roller)
25 Waste toner collecting container 26 Cleaning blade 27 Fixing device 28 Driving roller 29 Transfer roller 30 Bias power supply 31 Tension roller 32 Transfer conveyance belt 33 Driven roller 34 Paper 35 Paper feed roller 36 Adsorption roller

Claims (3)

A conductive member having a shaft core and an elastic layer on the outer periphery of the shaft core, and a surface layer on the outer periphery of the elastic layer;
The surface layer is
A polyester melamine resin comprising the following formulas (A), (B) and (C);
A polyester copolymer resin comprising the following formulas (A) and (B);
Conductive polyester, and the polyester melamine resin forms a matrix phase in the surface layer,
The polyester copolymer resin forms a domain phase in the surface layer; and
The conductive member, wherein the conductive fine particles are unevenly distributed in the matrix phase:

(In the formula (B), R ₁ is a straight chain alkylene group having 2 to 9 carbon atoms or a branched alkylene group having 6 to 9 carbon atoms, and R ₂ is a straight chain group having 2 to 8 carbon atoms. An alkylene group).   A process cartridge that is detachably attached to a main body of an electrophotographic image forming apparatus, the process cartridge including a conductive member, a toner regulating member, and a toner container, and the conductive member is defined in claim 1. A process cartridge comprising the conductive member according to claim 1.   An electrophotographic image forming apparatus having a photosensitive member and a conductive member disposed in contact with the photosensitive member, wherein the conductive member is the conductive member according to claim 1. Image forming apparatus.

Images