JP5748576B2 - Developing member, process cartridge, and electrophotographic image forming apparatus - Google Patents

Description

  The present invention relates to a developing member, a process cartridge, and an electrophotographic image forming apparatus that are used in contact with a photosensitive member.

  A developing member such as a developing roller used in an electrophotographic image forming apparatus is required to have an ability to impart an appropriate triboelectric charge to toner. In response to such a request, Patent Document 1 is obtained by copolymerizing a (meth) acrylate monomer and a copolymer monomer containing an amino group-containing (meth) acrylate monomer on the surface layer of the developing roller. In addition, a configuration including a positive charge control resin is disclosed.

JP 2005-031657 A

According to the study by the present inventors, it has been confirmed that the developing roller provided with the surface layer containing the charge control resin according to Patent Document 1 is excellent in the ability to impart triboelectric charge to the toner. However, as a result of further studies, the counter charge on the developing roller generated by the charged toner can be better released by reducing the electrical resistance of the surface layer in order to stabilize the developing bias. It was recognized that it was necessary to.
However, when conductive particles such as carbon black are added to the surface layer in order to reduce the electrical resistance of the surface layer, the elasticity of the surface layer is lowered. As a result, when the developing roller is left in contact with the developing blade for a long period of time in an environment of high temperature and high humidity (for example, a temperature of 40 ° C. and a relative humidity of 95%), In some cases, deformation (hereinafter referred to as permanent compression strain) that does not easily recover may occur in the contact portion. In the portion where the permanent compression distortion of the developing roller occurs, the triboelectric charge imparting ability to the toner and the toner coating amount differ. Therefore, when an electrophotographic image is formed using such a developing member, streak-like defects may occur in the electrophotographic image.
Further, the inventors formed an electrophotographic image using the developing roller according to Patent Document 1 in an environment of low temperature and low humidity (for example, a temperature of 0 ° C. and a relative humidity of 15%). As a result, the toner fine powder may adhere to the developing roller, and the triboelectric charge imparting ability of the toner may decrease over time.
SUMMARY OF THE INVENTION An object of the present invention is to provide a developing member that can stably impart an appropriate triboelectric charge to a toner even under various environments and whose performance is unlikely to deteriorate over time. is there.
Another object of the present invention is to provide an electrophotographic image forming apparatus and a process cartridge capable of stably forming high-quality electrophotographic images over a long period of time even under various environments.

  According to one aspect of the present invention, the surface of the shaft core is conductive, the conductive elastic layer covering the peripheral surface of the shaft core, and the conductive surface layer covering the peripheral surface of the elastic layer The surface layer contains polyurethane, carbon black, and an acrylic resin having an amino group in the molecule, and the surface layer comprises a polyurethane-containing matrix phase and polyurethane. There is provided a developing member having a sea-island type phase separation structure composed of a contained domain phase, wherein the acrylic resin is unevenly distributed in the domain phase.

  According to the present invention, it is possible to obtain a developing member that can stably impart an appropriate triboelectric charge to the toner and whose performance is less likely to deteriorate over time. In addition, according to the present invention, an electrophotographic image forming apparatus and a process cartridge capable of stably forming high-quality electrophotographic images over a long period of time even under various environments can be obtained.

It is sectional drawing perpendicular | vertical with respect to the longitudinal direction of the developing roller which concerns on this invention. FIG. 3 is a cross-sectional view parallel to the longitudinal direction in the vicinity of the surface of the developing roller according to the present invention. 1 is a schematic configuration diagram illustrating an example of an electrophotographic process cartridge according to the present invention. 1 is a schematic configuration diagram illustrating an example of an electrophotographic image forming apparatus according to the present invention. It is the schematic of an electric current value measuring apparatus.

FIG. 1 is a cross-sectional view perpendicular to the longitudinal direction of a developing roller 1 which is a developing member according to the present invention. The developing roller 1 has a columnar shape or a hollow cylindrical shape, and the surface thereof is a conductive shaft core body 2, and a conductive elastic layer 3 composed of at least one layer formed so as to cover the peripheral surface of the shaft core body. And a conductive surface layer 4 formed to cover the peripheral surface of the elastic layer.
Hereinafter, the developing roller 1 will be described in detail.

<Surface layer>
FIG. 2 is a cross-sectional view parallel to the longitudinal direction of the developing roller which is a developing member according to the present invention. The surface layer 4 includes at least polyurethane, carbon black, and an acrylic resin having an amino group in the molecule (hereinafter referred to as an amino group-containing acrylic resin). The surface layer 4 has a phase separation structure composed of a matrix phase 11 containing polyurethane and a domain phase 12 containing polyurethane, and the amino group-containing acrylic resin is unevenly distributed in the domain phase.

When the surface layer contains an amino group-containing acrylic resin, the surface layer has a high triboelectric chargeability. As a result, the developing roller according to the present invention has an effect of suppressing fogging on the electrophotographic image.
Further, since the amino group-containing acrylic resin is unevenly distributed in the domain phase, it is difficult for the toner to be fused to the surface of the developing roller, and a change in performance of the developing roller with time is suppressed. The present inventors have examined the reason why toner adheres to the surface of a developing roller when an electrophotographic image is formed under low temperature and low humidity conditions using the developing roller according to Patent Document 1. As a result, it was speculated that the fixation was caused by the following mechanism. That is, a developing roller having a surface layer in which an amino group-containing acrylic resin is uniformly dispersed has a high triboelectric charge imparting property to the toner, so that the toner charge amount increases and the toner is statically applied to the surface of the developing roller. Electrical adhesion also increases. Here, toner having a small particle diameter or toner fine powder has a strong electrostatic adhesion, and firmly adheres to the entire surface of the developing roller. In this case, it is difficult for a member such as a toner supply roller disposed in contact with the developing roller to enter the lower part of the toner layer formed on the surface of the developing roller, that is, the surface of the developing roller. As a result, scraping of the toner fixed on the surface of the developing roller becomes insufficient, and toner fusion further proceeds.

  On the other hand, in the present invention, since the amino group-containing acrylic resin is unevenly distributed in the domain phase, the degree of fusion of the toner differs between the domain phase portion and the matrix phase portion. Therefore, even when the toner adheres to the surface of the developing roller, the portion where the degree of toner adhering is the starting point of scraping by the toner supply roller or the like, and the adhered toner is easily scraped off. Inferred. As a result, the toner hardly adheres to the surface of the developing roller according to the present invention, and the temporal degradation of the triboelectric charge imparting ability can be suppressed.

Moreover, the surface layer according to the present invention can reduce the electric resistance of the surface layer without adding a large amount of carbon black that leads to an increase in compression set by adopting a phase separation structure.
In the case of a surface layer in which an amino group-containing acrylic resin is simply dispersed, the electric resistance of the surface layer tends to increase. The mechanism is not clear, but is presumed as follows. That is, since the amino group-containing acrylic resin generally has high electric resistance, the electric resistance of the surface layer containing the resin becomes high. Further, the resin acts as a dispersant for carbon black in the surface layer, and carbon black percolation is suppressed. Further, the resin covers the surface of the carbon black, thereby increasing the apparent resistance of the carbon black itself. As a result, it is considered that the electric resistance of the developing member having a surface layer simply containing the amino group-containing acrylic resin is increased.
On the other hand, in the present invention, since the amino group-containing acrylic resin is unevenly distributed in the domain phase, the amount of the amino group-containing acrylic resin in the matrix phase that is a continuous phase is relatively small. In addition, overdispersion of the carbon black in the matrix phase with the amino group-containing acrylic resin and coating of the carbon black with the amino group-containing acrylic resin are suppressed. For these reasons, it is considered that the increase in the electrical resistance of the matrix phase is suppressed and the increase in the electrical resistance of the surface layer itself is also suppressed.
Furthermore, since the surface layer according to the present invention has a phase separation structure, compression set is less likely to occur. The reason is considered to be that the matrix phase and the domain phase contain polyurethane, have natural frequencies close to stress, and have high responsiveness to external force. In addition, since the matrix phase and the domain phase have a phase separation structure, it is considered that the interface between each other is closely cross-linked through a urethane bond or the like. Therefore, it is considered that plastic deformation at the interface when subjected to an external force is suppressed and excellent elasticity is exhibited.

  As a result, the developing member according to the present invention is not easily recovered from deformation due to a decrease in frictional charge imparting ability to the toner, adhesion of the toner to the surface, and contact of the contact member over a long period of time even under various environments. It is thought that suppression was possible.

  The polyurethane according to the present invention is not a generic term for a polymer having a single composition, but a generic term for polymers containing urethane bonds. Polyurethane is composed of soft segments such as ester groups and ether groups, and hard segments such as urethane bonds, allophanate bonds, and burette bonds. Polyurethanes are generally classified into ester polyurethanes, ether polyurethanes, carbonate polyurethanes, acrylic polyurethanes, and olefin polyurethanes according to the chemical bond species forming the soft segment. These polyurethanes can be obtained by curing a mixture of a polyol that forms a soft segment and an isocyanate that forms a hard segment.

  The surface layer 4 according to the present invention has a sea-island type phase separation structure composed of a polyurethane matrix phase 11 and a polyurethane domain phase 12. Examples of such a configuration include those obtained by synthesizing two types of polyols having different polarities (SP values) and isocyanate. 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).

  The SP value of a polyol can be easily controlled by adjusting the blending ratio of isocyanate and polyol in a prepolymer type polyol (polyurethane polyol prepolymer) mainly composed of polyol and isocyanate. The SP value also changes depending on the chemical bond type and molecular weight of the polyol.

  In the present invention, the SP value difference between the two polyols is preferably 0.1 or more and 2.0 or less, more preferably 0.3 or more and 1.0 or less. When the SP value difference is 0.1 or more, the two types of polyols can easily control the sea-island type phase separation structure, and the size of the domain phase can be easily controlled. Further, when the SP value difference is 2.0 or less, a surface layer that is excellent in smoothness and mechanical properties of the surface layer to be produced is likely to be obtained. When the SP value difference becomes excessively large, the smoothness of the surface layer is lost, and the toner scraping property of the toner supply roller tends to be impaired. In addition, the reactivity between polyol and isocyanate is reduced, and unreacted substances in the surface layer increase, and mechanical properties such as compression set are likely to decrease due to a decrease in strength at the interface between the matrix phase and the domain phase. Become.

  In addition, two kinds of polyols having moderately different polarities can easily control a sea-island type phase separation structure composed of a matrix phase and a domain phase depending on the blend ratio. The weight ratio of the matrix phase polyol to the domain phase polyol (domain phase polyol weight / matrix phase polyol weight) is preferably from 1/10 to 1/1, more preferably from 1/5 to 1 /. 2 or less. When the weight ratio of the matrix phase polyol to the domain phase polyol is 1/10 or more, triboelectric chargeability is easily obtained, and when it is 1/1 or less, an effect on toner fusion is easily obtained. It is easy to suppress the increase in resistance of the layer.

  The equivalent circle diameter of the domain phase is preferably 1 μm or more and 30 μm or less. If it is 1 μm or more, it is generally easy to obtain a high triboelectric charge imparting ability for a toner having an average particle diameter of several μm, and if it is 30 μm or less, sufficient toner scraping property by the toner supply roller can be easily obtained. . Here, the equivalent circle diameter is the diameter of a circle having the same area as the area of the domain phase on the surface of the developing roller.

  In the present invention, the domain phase can be identified by a measuring device such as a scanning electron microscope (SEM) or a scanning transmission electron microscope (STEM). In addition, with respect to those having different conductivity between the matrix phase and the domain phase, the domain phase can be identified by mapping with a scanning probe microscope (SPM).

  Furthermore, in the present invention, it is preferable to use a polyester polyol and a polyether polyol as the polyol. The ester group has a higher polarity than the ether group, and the polyester polyol and the polyether polyol containing these ester groups are appropriately different in polarity, so that it is suitable for forming a sea-island type phase separation structure. Furthermore, ether polyurethane and ester polyurethane have a lower bond strength of soft segments in the polyurethane than carbonate polyurethane and acrylic polyurethane, and an excessive increase in hardness is suppressed. For this reason, since damage to the toner is reduced, it is suitable for use on the surface layer of the developing roller.

  Furthermore, the polyurethane contained in the matrix phase preferably contains an ester group in the molecule, and the polyurethane contained in the domain phase preferably contains an ether group in the molecule. That is, it is more preferable that the matrix phase includes ester polyurethane and the domain phase includes ether polyurethane. The ester group has a strong intermolecular force, and is characterized by excellent mechanical properties such as wear resistance, Young's modulus, and breaking strength. By applying it to the matrix phase, the surface layer exhibits a low compression set. . In addition, since an electron cloud of the highest occupied molecular orbital, which is an electron donating property, is concentrated in the ether group, a superior triboelectric charge imparting property is exhibited by a synergistic effect with the amino group-containing acrylic resin.

  Although the polyester polyol in this invention is not specifically limited, The polyester polyol obtained by direct esterification reaction or ring-opening polymerization reaction can be used conveniently. Alternatively, a polyurethane polyol prepolymer obtained by extending a chain of polyester polyol and isocyanate can be suitably used. The polyester polyol synthesized by direct esterification reaction can be obtained by dehydrating condensation of a polybasic acid and a polyhydric alcohol as raw materials.

  Polybasic acids include adipic acid, isophthalic acid, tetrachlorophthalic anhydride, het acid, tetrabromophthalic anhydride, phthalic anhydride, hasophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic acid, sebacin Acid, fumaric acid, trimellitic acid, dimer acid, maleic anhydride, 1,12-dodecanedioic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 5- Examples include sodiosulfoisophthalic acid. Among these, adipic acid, isophthalic acid, terephthalic acid, and sebacic acid are particularly preferable because they are easily available.

  Examples of the polyhydric alcohol include 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, ethylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,5-pentanediol, 1,6 -Hexanediol, neopentyl glycol, bisphenol A, glycerin, pentaerythritol, trimethylolpropane, trimethylolethane, 1,4-cyclohexanedimethanol, 2,2,4-trimethyl-1,3-pentanediol, 2-butyl 2-ethyl-1,3-propanediol, hydroxypivalylhydroxypivalate, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 2- Methyl-1,3-propanedi Lumpur, e.g., 2,4-diethyl-1,5-pentanediol can be mentioned as examples.

  Furthermore, polycaprolactone diol obtained by ring-opening polymerization reaction of ε-caprolactone, or polyester polyol synthesized by prepolymerizing polycaprolactone diol is also preferable. Among the polycaprolactone diols, those that are non-crystalline or have a low melting point are particularly preferred from the viewpoints of compatibility with isocyanates and solubility in solvents.

  In addition, the polyether polyol in the present invention is not particularly limited, but a polyether polyol itself or a polyurethane ether polyol prepolymer using a polyether polyol as a raw material is preferably used. For example, polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG), a copolymer of tetrahydrofuran (THF) and neopentyl glycol (for example, trade name: PTXG, manufactured by Asahi Kasei Fibers Corporation), Examples thereof include a copolymer of THF and 3-methyltetrahydrofuran (for example, trade name: PTG-L, manufactured by Hodogaya Chemical Co., Ltd.) and a polyurethane ether polyol prepolymer using these as raw materials.

  These polyols are preferably in the range of 500 ≦ Mn ≦ 20000, although the optimum Mn varies depending on the type of isocyanate used as the curing agent, the number average molecular weight (Mn), and the availability of urethane prepolymerization. By setting Mn to 500 or more, it is possible to suppress an increase in the density of crosslinking points and to suppress an increase in the hardness of the surface layer under low temperature and low humidity. On the other hand, when Mn is 20000 or less, an excessive decrease in the density of crosslinking points can be suppressed, and an increase in compression set can be prevented.

Furthermore, in the present invention, the polyurethane contained in the matrix phase contains at least one structure selected from the following formulas (c) and (d) between two adjacent urethane groups, and is contained in the domain phase. It is preferable that the polyurethane includes at least one structure selected from the following formulas (f), (g) and (h) and a structure (e) between two adjacent urethane groups.

  This indicates that the polyol having each structure has a specifically low melting point as compared with the melting point of a general polyhydric alcohol. Therefore, since the degree of crystallinity in the soft segment in the polyurethane can be easily controlled, it contributes to the suppression of the increase in hardness, particularly under low temperature and low humidity, from the viewpoint of controlling the mechanical properties.

  Among them, the polyurethane contained in the matrix phase includes the structure of the above formula (d) between two adjacent urethane groups, and the polyurethane contained in the domain phase has the above formula between two adjacent urethane groups. A material including at least one structure selected from (g) and (h) and the structure (e) exhibits a more excellent effect on toner fusion. The ester polyurethane containing the structure of the above formula (d) exhibits a particularly low melting point among polyurethanes containing an ester group, and can reduce stress on the toner. The ether polyurethane containing at least one structure selected from the above formulas (g) and (h) and the structure of (e) becomes more flexible in the low temperature range than the polyurethane containing the above formula (d). Cheap. Since the domain phase is more flexible than the matrix phase, the torque between the domain phase and the toner supply roller is increased as compared with the case where the matrix phase is more flexible than the domain phase. Therefore, it is presumed that the toner scraping property of the domain phase having a strong electrostatic adhesive force with the toner is improved and the toner fusion is further suppressed.

  Although it does not specifically limit as isocyanate, The following can be mentioned as an example. Diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI) 1,5-naphthalene diisocyanate, 3,3′-dimethylbiphenyl-4,4′-diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, carbodiimide-modified MDI, xylylene diisocyanate, Trimethylhexamethylene diisocyanate, toluene diisocyanate (TDI), naphthylene diisocyanate, paraphenyl diisocyanate, hexamethylene diisocyanate, polymethylene polyphenylene polyisocyanate (polymeric MDI), copolymers thereof, block bodies and mixtures thereof.

  Among those exemplified above, a prepolymer type isocyanate having an ether group and an ester group in a modified part (soft segment part) is particularly preferable because of compatibility with a polyol and easy adjustment of physical properties. As the raw material constituting the modified part having an ether group and an ester group, the same materials as those used for the polyol can be suitably used. The isocyanate is preferably prepared from at least one selected from diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), polymethylene polyphenylene polyisocyanate (polymeric MDI), and toluene diisocyanate (TDI). The above four types of materials not only have good reactivity with polyols, but are relatively easy to maintain toughness compared to isocyanate raw materials such as xylylene diisocyanate (XDI), and compression set This is preferable from the viewpoint of controlling the above.

  Further, in the isocyanate compound in the present invention, the optimum Mn differs depending on whether or not urethane prepolymerization is possible and the type of polyol compound used for the reaction and Mn, but it is preferable that the range is 2000 ≦ Mn ≦ 12000. When Mn is 2000 or more, an increase in the density of crosslinking points can be suppressed, and an increase in surface layer hardness under low temperature and low humidity can be suppressed. On the other hand, when Mn is 12000 or less, an excessive decrease in the density of crosslinking points can be suppressed, an increase in compression set can be prevented, and the initial toner can be prevented from sticking due to excessive softening.

  It is particularly preferable that the isocyanate compound has an isocyanate index in the range of 1.0 to 1.5 with respect to the polyol compound. By being in the said range, the raise of the compression set by the production | generation of an unreacted substance and the raise of excessive hardness can be suppressed. The isocyanate index indicates the ratio ([NCO] / [OH]) between the number of moles of isocyanate groups in the isocyanate compound and the number of moles of hydroxyl groups in the polyol compound.

  For the composition of the structures of the above formulas (c) to (h) in the polyurethane, use the infrared spectroscopy (IR) method and the pyrolysis gas chromatography (Pyr-GC) method after hydrolyzing the polyurethane. Can be confirmed.

  In the surface layer according to the present invention, an amino group-containing acrylic resin is unevenly distributed in the domain phase. The amino group-containing acrylic resin can be unevenly distributed in the domain phase by increasing the affinity with the polyol that forms the domain phase. By setting the SP value of the amino group-containing acrylic resin to a value close to that of the polyol forming the domain phase, the amino group-containing acrylic resin can increase the affinity with the domain phase.

Regarding the uneven distribution of the amino group-containing acrylic resin in the domain phase, it can be measured by using a time-of-flight secondary ion mass spectrometer (TOF-SIMS) which shows a measurement method below. In the present invention, the uneven distribution of the amino group-containing acrylic resin is defined as follows. The total ionic strength of the matrix phase and the domain phase having a mass of 1.5 amu or more and 1850 amu or less as measured by TOF-SIMS is σ _{M, T} , σ _{D, T} , respectively, and the ionic strength derived from the amino group is σ _{M, When A 1} , σ _{D, and A} are satisfied, the following expressions (A) and (B) are satisfied.
(A) σ _{M, A} / σ _{M, T} ≦ 0.0001
(B) (σ _{D, A} / σ _{D, T} ) / (σ _{M, A} / σ _{M, T} ) ≧ 10
(Σ _{D, A} / σ _{D, T} ) / (σ _{M, A} / σ _{M, T} ) being 10 or more indicates that the amino group-containing acrylic resin is unevenly distributed in the domain phase. Furthermore, when σ _{M, A} / σ _{M, T} is 0.0001 or less, the amount of amino group-containing acrylic resin contained in the matrix phase is sufficiently small, the charge imparting property of the matrix phase is maintained moderately, and the developing roller The increase in electrical resistance is suppressed. As a result, image adverse effects caused by toner fusion in a low-temperature and low-humidity environment, which is an effect of the present invention, and counter-charging to the developing roller surface during development are suppressed.

  The number average molecular weight (Mn) of the amino group-containing acrylic resin is preferably 5000 ≦ Mn ≦ 50000. When Mn is 5000 or more, bleeding out can be suppressed, and blotch can be suppressed particularly in a low temperature and low humidity environment. Further, by setting Mn to 50000 or less, the amino group-containing acrylic resin can be easily dispersed uniformly in the domain phase, and the triboelectric chargeability can be optimized.

  Moreover, it is preferable that content of an amino group containing acrylic resin is the range of 0.5 mass part or more and 10 mass parts or less with respect to 100 mass parts of polyurethane components of a surface layer. More preferably, it is 1 part by mass or more and 5 parts by mass or less. By setting the amount to 0.5 parts by mass or more, it is possible to provide high triboelectric chargeability to the toner. Further, by setting the amount to 10 parts by mass or less, it is possible to suppress the stress on the toner accompanying the increase in the hardness of the domain phase.

  Further, the amino group-containing acrylic resin is preferably produced by copolymerizing a (meth) acrylic acid ester monomer and an amino group-containing monomer as a structural unit (monomer). Preferably, the polymerization ratio of the amino group-containing monomer is 10 mol% or more and 70 mol% or less. By setting the polymerization ratio of the (meth) acrylic acid ester monomer in the amino group-containing acrylic resin to 10 mol% or more, the amino group-containing acrylic resin can be easily oriented in the surface direction of the developing roller, and sufficient triboelectric chargeability can be obtained. It is done. On the other hand, it becomes easy to disperse | distribute uniformly in a domain phase by setting it as 70 mol% or less.

  Examples of the (meth) acrylic acid ester monomer that is a raw material for the amino group-containing acrylic resin include the following substances. Methyl methacrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, iso-butyl (meth) acrylate, n-amyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, iso-octyl (meth) acrylate, n-nonyl (meth) acrylate, n-lauryl (meth) acrylate, n-tridecyl (meth) acrylate, n- Stearyl (meth) acrylate, isobornyl (meth) acrylate. These monomers can be used alone or in combination of two or more.

  In particular, among (meth) acrylic acid ester monomers, methyl methacrylate, cyclohexyl (meth) acrylate, n-lauryl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, and 2-ethylhexyl (Meth) acrylate is preferred from the viewpoint of compatibility with polyurethane and adjusting the hardness of the surface layer.

  Examples of the amino group-containing monomer include the following substances. N, N-dimethylaminomethyl (meth) acrylate, N, N-diethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N- Dimethylaminopropyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, pN, N-dimethylaminophenyl (meth) acrylate, pN, N-diethylaminophenyl (meth) acrylate, pN , N-dipropylaminophenyl (meth) acrylate, pN, N-dibutylaminophenyl (meth) acrylate, pN-laurylaminophenyl (meth) acrylate, pN-stearylaminophenyl (meth) acrylate, p-N, N-dimethylaminobenze (Meth) acrylate, pN, N-diethylaminobenzyl (meth) acrylate, pN, N-dipropylaminobenzyl (meth) acrylate, pN, N-dibutylaminobenzyl (meth) acrylate, pN -Laurylaminobenzyl (meth) acrylate, pN-stearylaminobenzyl (meth) acrylate, (meth) acryloyloxymethylmorpholine, (meth) acryloyloxyethylmorpholine, N, N-dimethylaminoethyl (meth) acrylamide N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, pN, N-dimethylaminophenyl (meth) acrylamide, p -N, N- Ethylaminophenyl (meth) acrylamide, pN, N-dipropylaminophenyl (meth) acrylamide, pN, N-dibutylaminophenyl (meth) acrylamide, pN-laurylaminophenyl (meth) acrylamide, p -N-stearylaminophenyl (meth) acrylamide, pN, N-dimethylaminobenzyl (meth) acrylamide, pN, N-diethylaminobenzyl (meth) acrylamide, pN, N-dipropylaminobenzyl (meth) ) Acrylamide, pN, N-dibutylaminobenzyl (meth) acrylamide, pN-laurylaminobenzyl (meth) acrylamide, pN-stearylaminobenzyl (meth) acrylamide and the like. “(Meth) acrylamide” means methacrylamide or acrylamide. These monomers can be used alone or in combination of two or more.

但し、上記式（ａ）および式（ｂ）中、Ｒ_１およびＲ_５は水素原子もしくはメチル基、Ｒ_２は炭素数２乃至４のアルキレン基、Ｒ_３およびＲ_４は炭素数１乃至４のアルキル基、Ｒ_６は炭素数１乃至８のアルキル基である。 A particularly preferable combination of monomers is a combination in which an amino group-containing monomer has a structure represented by the following formula (a) and a (meth) acrylic acid ester monomer has a structure represented by the following formula (b).

However, in the above formula (a) and Formula (b), _{R 1} and _{R 5} is a hydrogen atom or a methyl group, _{R 2} is an alkylene group having 2 to 4 carbon atoms, _{R 3} and _{R 4} having 1 to 4 carbon atoms The alkyl group R ₆ is an alkyl group having 1 to 8 carbon atoms.

R ₁ and R ₅ each independently represents a hydrogen atom or a methyl group. By making R ₂ an alkylene group having 2 or more carbon atoms, it is possible to suppress a decrease in the electron density of the amino group due to an adjacent ester and to easily obtain high charge imparting properties. In addition, when R ₂ is an alkylene group having 4 or less carbon atoms, the mobility of the amino group can be appropriately maintained, and the charge imparting property of the amino group can be greatly exhibited. By making R ₃ and R ₄ an alkyl group having 1 or more carbon atoms, the electron density of the amino group is increased, and high chargeability can be easily obtained. Furthermore, by making R ₃ and R ₄ an alkyl group having 4 or less carbon atoms, the steric hindrance of the alkyl group associated with the amino group is not excessive, and the high charge imparting property due to the amino group is easily exhibited. . By making R ₆ an alkyl group having 1 to 8 carbon atoms, the polarity of the amino group-containing acrylic resin can be easily controlled when polymerized with the amino group-containing monomer.

  The SP value of the amino group-containing acrylic resin can be controlled by selecting the combination and the molar ratio of each raw material monomer.

  The surface layer according to the present invention contains carbon black. Carbon black contributes to the optimization of the mechanical properties and conductivity of the surface layer. By containing carbon black, hard carbon black is present in a dispersed state on the outermost surface of the flexible surface layer containing polyurethane. Thereby, the adhesiveness of the surface layer can be reduced, and toner fusion can be suppressed. Further, the surface layer of the developing roller is required to appropriately control the conductivity so as to prevent the residual charge remaining on the developing roller caused by the charged toner and to suppress image adverse effects such as ghost and development unevenness. . Since carbon black can control conductivity in a small amount, it is easy to obtain appropriate conductivity while suppressing an increase in compression set of polyurethane. Therefore, in the present invention, in order to achieve toner fusion suppression and low compression set, it is necessary to contain carbon black as an essential component.

  The content of the carbon black in the surface layer is preferably in the range of 1 to 40 parts by mass with respect to 100 parts by mass of the polyurethane component of the surface layer. More preferably, it is the range of 5 to 30 mass parts. When the carbon black content is 1 part by mass or more, not only moderate conductivity can be obtained, but also an increase in the friction coefficient can be suppressed. On the other hand, by being 40 parts by mass or less, not only an increase in damage to the toner due to an excessive increase in hardness of the surface layer containing polyurethane can be suppressed, but also an increase in compression set can be suppressed.

  The average primary particle diameter of the carbon black is 15 nm or more in consideration of imparting appropriate conductivity to the surface layer containing polyurethane and expressing mechanical properties such as a low friction coefficient and a low compression set. The thickness is preferably 150 nm or less. The oil absorption of dibutyl phthalate (DBP) of carbon black is preferably 20 ml / 100 g or more and 300 ml / 100 g or less for the same reason. Furthermore, the pH of the carbon black is preferably 2 or more and 7 or less from the viewpoint of stabilizing dispersion with polyurethane. As such carbon black, those produced by a method such as a channel method, a furnace method, or a thermal method can be suitably used. Furthermore, you may mix | blend two or more types of carbon black according to a required physical property.

  The surface layer may contain spherical fine particles that form an uneven shape on the surface in order to impart an appropriate surface roughness to the surface of the developing roller. When the surface layer contains spherical fine particles, the surface roughness of the surface of the developing roller can be made uniform, and the toner conveyance amount can be made constant. The spherical fine particles preferably have a volume average particle size of 5 μm or more and 30 μm or less. For the 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 the measurement, a small amount of surfactant is added to 10 ml of water, 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. The content of the spherical fine particles is preferably 1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the polyurethane component of the surface layer.

  Examples of the material of 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 necessary, as long as the functions of the above components are not impaired. Various additives such as auxiliaries can be contained.

  Moreover, as thickness of the said surface layer, 2 micrometers or more and 100 micrometers or less are preferable, More preferably, they are 4 micrometers or more and 40 micrometers or less. If the thickness of the surface layer is 2 μm or more, it is possible to prevent an increase in resistance due to the domain phase in the surface layer penetrating from the surface of the developing roller to the elastic layer, that is, through the surface layer. Deformation of the developing roller due to contact can be suppressed. If the thickness of the surface layer is 100 μm or less, the developing roller can be prevented from having high hardness and toner fusing can be suppressed. In addition, the film thickness of the formed surface layer was measured using a digital microscope (trade name: VH-2450, manufactured by Keyence Corporation). A total of nine locations were measured along the longitudinal direction of the developing roller at three equal intervals from the end of the developing roller and at three equal intervals along the circumferential direction of the developing roller, and an arithmetic average of the obtained values The value is the film thickness of the surface layer.

  As a method for forming a coating film of a coating for forming a surface layer containing the above polyol, isocyanate compound, amino group-containing acrylic resin, carbon black, etc. on the elastic layer, a coating method such as spraying, dipping, or roll coating is used. Can be mentioned. And the electroconductive surface layer which coat | covers the surrounding surface of an elastic layer can be formed by hardening the coating film formed on the elastic layer after drying.

<Shaft core>
The material of the conductive shaft core 2 is not particularly limited as long as the surface is conductive, and can be appropriately selected from materials such as carbon steel, alloy steel, cast iron, and conductive resin.

<Elastic layer>
The conductive elastic layer 3 covering the peripheral surface of the shaft core body is provided to give the developing roller the elasticity required in the apparatus to be used. As a specific configuration, either a solid body or a foam may be used. Further, the elastic layer may be a single layer or a plurality of layers. For example, since the developing roller and the charging roller are always in pressure contact with the photosensitive member and the toner, an elastic layer having characteristics of low hardness and low compression set in order to reduce mutual damage between these members. Is provided.

  Examples of the material for the elastic layer include natural rubber, isoprene rubber, styrene rubber, butyl rubber, butadiene rubber, fluorine rubber, urethane rubber, and silicone rubber. These can be used alone or in combination of two or more.

  The elastic layer contains a cross-linking agent, a catalyst, a dispersion accelerator, etc. as a conductive agent, a non-conductive filler, and various other additive components necessary for molding depending on the function required for the developing roller. May be.

  As the conductive agent contained in the elastic layer, it is possible to use various conductive metals or alloys, conductive metal oxides, and electronic conductive agents and ionic conductive agents such as fine powders of insulating substances coated with these. . These conductive agents can be used alone or in combination of two or more in the form of powder or fiber. Of these, carbon black, which is an electronic conductive agent, is preferable because it is easy to control conductivity and is economical.

By containing such a conductive agent, for example, a volume resistivity of 1 × 10 ⁴ Ω · cm or more and 1 × 10 ¹⁰ Ω · cm or less can be imparted to the elastic layer. A developing roller having a volume resistivity of the elastic layer within this range has uniform charge controllability with respect to the toner. The volume resistivity in the elastic layer of the developing roller is more preferably 1 × 10 ⁴ Ω · cm or more and 1 × 10 ⁹ Ω · cm or less.

  Examples of the non-conductive filler that may be contained in the elastic layer include the following. Diatomaceous earth, quartz powder, dry silica, wet silica, titanium oxide, zinc oxide, aluminosilicate, calcium carbonate, zirconium silicate, aluminum silicate, talc, alumina, iron oxide, etc.

  The elastic layer imparts the elasticity required for the developing roller, and as its hardness, for example, the Asker C hardness is preferably 10 degrees or more and 80 degrees or less. If the Asker C hardness of the elastic layer 12 is 10 degrees or more, the oil component can be prevented from seeping out from the rubber material constituting the elastic layer, and contamination of the photoreceptor can be suppressed. Further, if the Asker C hardness of the elastic layer is 80 degrees or less, the stress on the toner can be suppressed, and the deterioration of the image quality of the output image can be suppressed.

  Here, Asker C hardness can be defined by a measured value measured by an Asker rubber hardness meter C type (manufactured by Kobunshi Keiki Co., Ltd.) using a test piece separately prepared in accordance with Japan Rubber Association standard SRIS 0101.

  For example, in the case of a developing roller, the thickness of the elastic layer may be 0.5 mm or more and 50 mm or less, and more preferably 1 mm or more and 10 mm or less.

  The elastic layer may be molded by various methods such as extrusion molding, press molding, injection molding, liquid injection molding, and cast molding, and heat-cured at an appropriate temperature and time for the circumference of the shaft core body. The method of shape | molding so that a surface may be mentioned can be mentioned. The elastic layer can be accurately formed around the shaft core body by injecting an uncured elastic layer material into a cylindrical mold having the shaft core body and heating and curing the material.

  FIG. 3 is a schematic configuration diagram showing an example of an electrophotographic process cartridge according to the present invention. The process cartridge 17 of the present invention includes at least a developing roller 1, a developing blade 21, and a toner container 20, and the developing roller 1 is the developing roller, and can be detachably mounted on the electrophotographic image forming apparatus main body. . Further, according to the present invention, a thin layer of toner is formed on the surface of the developing roller 1, the developing roller 1 is placed in contact with the photosensitive member 18, 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. This process cartridge can be an all-in-one process cartridge integrated with the photosensitive member 18, the cleaning blade 26, the waste toner container 25 and the charging roller 24, as in the process cartridge 17 shown in FIG. 3.

  FIG. 4 is a schematic configuration diagram showing an example of an electrophotographic image forming apparatus using a process cartridge having a developing roller according to the present invention. The electrophotographic image forming apparatus having the photosensitive member and the developing roller disposed in contact with the photosensitive member in FIG. 4 includes a developing device 22 including a developing roller 1, a toner supply roller 19, a toner container 20, and a developing blade 21. It is detachably attached. Further, the process cartridge 17 including the developing roller 1, the developing blade 21, and the toner container 20 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 photoconductor 18 rotates in the direction of the arrow, is uniformly charged by a charging roller 24 for charging the photoconductor 18, and the surface of the photoconductor 18 is exposed by laser light 23 that is an exposure means for writing an electrostatic latent image on the photoconductor 18. An electrostatic latent image is formed. The electrostatic latent image is developed by applying the toner 20a in the toner container 20 by the developing device 22 arranged in contact with the photoreceptor 18, and is 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 image forming apparatus through the paper feed roller 35 and the suction roller 36, and is transported between the photoconductor 18 and the transfer roller 29 by the 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 operation.

  The developing device 22 includes a toner container 20 containing toner 20a as a one-component developer, a photosensitive member 18 positioned in an opening extending in the longitudinal direction in the toner container 20, and a developer carrying member disposed oppositely. Development roller 1. The developing device 22 develops and visualizes the electrostatic latent image on the photoconductor 18.

  Further, as the developing blade 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. . Further, it is possible to control the toner layer on the developing roller by applying a voltage higher than the voltage applied to the developing roller 1 to the developing blade 21. For this purpose, the developing blade 21 is made of SUS or phosphor bronze. It is preferable to use a thin plate. Note that a voltage is applied from the bias power source 30 to the developing roller 1 and the developing blade 21, but the voltage applied to the developing blade 21 is a voltage that is 100 V to 300 V larger in absolute value than the voltage applied to the developing roller 1. It is preferable that

  The developing process in the developing device 22 will be described below. Toner is applied onto the developing roller 1 by a toner supply roller 19 that is rotatably supported. The toner applied on the developing roller 1 is rubbed against the developing blade 21 by the rotation of the developing roller 1. Here, the toner applied on the developing roller is uniformly coated on the developing roller by the bias applied to the developing blade 21. The developing roller 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 developing roller 1.

  The toner supply roller 19 has 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 of the toner supply roller 19. This is preferable in terms of supply and stripping of undeveloped toner on the developing roller 1. In this embodiment, an elastic roller provided with polyurethane foam around the shaft core of the toner supply roller 19 is used.

  The contact width of the toner supply roller 19 with respect to the developing roller 1 is preferably 1 mm or more and 8 mm or less, and the developing roller 1 is preferably provided with a relative speed at the contact portion.

  The developing roller, process cartridge, and electrophotographic image forming apparatus of the present invention will be specifically described below. First, a method for producing an elastic layer roller in Examples and Comparative Examples of the present invention will be specifically illustrated and described.

<Method for producing elastic layer roller>
The elastic layer roller used for manufacturing the developing roller according to the example and the comparative example was manufactured as follows. A shaft core body made of stainless steel (SUS304) and having a diameter of 8 mm was prepared as the shaft core body. A primer (trade name: DY35-051, manufactured by Toray Dow Corning Co., Ltd.) was applied to the peripheral surface of the shaft core, and baked at a temperature of 150 ° C. for 30 minutes. The thickness of the primer after baking was 1 μm.

  A base material A of a liquid silicone rubber material having a vinyl group was prepared by mixing the materials shown in Table 1 below.

  The materials shown in Table 2 below were mixed to prepare a base material B of a liquid silicone rubber material having SiH groups and vinyl groups.

（＊）液状シリコーンゴム材料のベース材料Ａおよびベース材料Ｂに含有するビニル基１モルに対して、ＳｉＨ基が１．１モルとなる量。

(*) The amount of SiH group is 1.1 mol with respect to 1 mol of vinyl group contained in base material A and base material B of the liquid silicone rubber material.

  The base material A and the base material B were mixed at a mass ratio of 1: 1 to obtain an unvulcanized liquid silicone rubber material. Next, the shaft core was placed inside a cylindrical mold, and the unvulcanized silicone rubber material was injected into the mold (cavity). Subsequently, the mold was heated to cure and cure the silicone rubber material at a temperature of 150 ° C. for 15 minutes, and then cooled to remove the mold. Thereafter, heating was performed at a temperature of 180 ° C. for 1 hour to complete the curing reaction, and a conductive elastic layer made of silicone rubber was provided so as to cover the periphery of the shaft core body, thereby producing an elastic layer roller A1. The diameter of the elastic layer roller A1 produced here was 12 mm.

  Next, the method for synthesizing the polyol and the prepolymer type isocyanate compound used for the preparation of the coating material for forming the surface layer used in Examples and Comparative Examples of the present invention will be specifically illustrated and described.

<Method for synthesizing polyol (PO1, 2)>
Prepolymer type polyether polyol 1 (PO1) was synthesized as follows. 21 parts by mass of an isocyanate compound for chain extension (trade name: Takenate D140N, manufactured by Mitsui Takeda Chemical Co., Ltd.) was added to 100 parts by mass of polytetramethylene glycol (trade name: PTMG2000, manufactured by Sanyo Chemical Industries). Furthermore, 4 parts by mass of ethylene glycol and 4 parts by mass of 1,1,1-trimethylolpropane were mixed stepwise in a methyl ethyl ketone (MEK) solvent. This was reacted at a temperature of 80 ° C. for 5 hours under a nitrogen atmosphere to obtain a prepolymer type polyether polyol 1 (PO1).

  Prepolymer type polyether polyol 2 (PO2) was synthesized as follows. Polytetramethylene glycol (trade name: PTMG1000, manufactured by Sanyo Chemical Industries) was used, and 1,1,1-trimethylolpropane was used in an amount of 3 parts by mass. Other than that was carried out similarly to the prepolymer type polyether polyol 1, and obtained the prepolymer type polyether polyol 2 (PO2).

  Except for the polyols (PO1) and (PO2), the following commercially available polyols (PO3 to PO10) were used.

<Polyols (PO3 to PO10) used in Examples and Comparative Examples>
Polyether polyol 3 (PO3) (trade name: PTG-L2000, composed of tetrahydrofuran and 3-methyltetrahydrofuran, manufactured by Hodogaya Chemical Co., Ltd.)
Polyether polyol 4 (PO4) (trade name: PTG-L1000, composed of tetrahydrofuran and 3-methyltetrahydrofuran. Manufactured by Hodogaya Chemical Co., Ltd.)
Polyether polyol 5 (PO5) (trade name: PTXG-1800, consisting of tetrahydrofuran and neopentyl glycol, manufactured by Asahi Kasei Fibers Co., Ltd.)
Polyester polyol 6 (PO6) (trade name: P-5010, consisting of 1-methyl-1,5-pentanediol and adipic acid. Manufactured by Kuraray Co., Ltd.)
Polyester polyol 7 (PO7) (trade name: P-3050, consisting of 3-methyl-1,5-pentanediol and sebacic acid, manufactured by Kuraray Co., Ltd.)
Polyester polyol 8 (PO8) (trade name: P-2050, consisting of 3-methyl-1,5-pentanediol and sebacic acid, manufactured by Kuraray Co., Ltd.)
Polyester polyol 9 (PO9) (trade name: L-205AL, manufactured by Daicel Chemical Industries, Ltd.)
Polyester polyol 10 (PO10) (trade name: F1212-29, consisting of 1,6-hexanediol, adipic acid and isophthalic acid, manufactured by ADEKA)

  Table 3 shows the structure, SP value, and measurement results of Mn contained in each polyol.

<Synthesis Method of Prepolymer Type Isocyanate Compound>
Prepolymer type isocyanate compound 1 (Pre1) was synthesized as follows.
Polypropylene glycol (trade name: Exenol 720, manufactured by Asahi Glass Co., Ltd.): 100 parts by mass Polyethylene polyphenylene polyisocyanate (trade name: Millionate MR-200, manufactured by Nippon Polyurethane Industry Co., Ltd.): 95 parts by mass
In a nitrogen atmosphere, the material was heated and reacted at a temperature of 90 ° C. for 2 hours. Thereafter, butyl cellosolve was added to a solid content of 70% by mass. Then, 28 mass parts of MEK oxime was dripped at the temperature of 50 degreeC to the reaction material, and prepolymer type isocyanate 1 (Pre1) was obtained.

Prepolymer type isocyanate compound 2 (Pre2) was synthesized as follows.
PO4 (trade name: PTG-L1000, manufactured by Hodogaya Chemical Co., Ltd.): 100 parts by massPolymethylene polyphenylene polyisocyanate (trade name: Millionate MR-200, manufactured by Nippon Polyurethane Industry Co., Ltd.): 82 parts by mass
In a nitrogen atmosphere, the material was heated and reacted at a temperature of 90 ° C. for 2 hours. Thereafter, butyl cellosolve was added to a solid content of 70% by mass. Then, 43 mass parts of MEK oxime was dripped at the temperature of 50 degreeC to the reaction material, and prepolymer type isocyanate 2 (Pre2) was obtained.

Prepolymer type isocyanate compound 3 (Pre3) was synthesized as follows.
PO10 (trade name: F1212-29, manufactured by ADEKA): 100 parts by massPolymethylene polyphenylene polyisocyanate (trade name: Millionate MR-200, manufactured by Nippon Polyurethane Industry Co., Ltd.): 77 parts by mass
In a nitrogen atmosphere, the material was heated and reacted at a temperature of 90 ° C. for 2 hours. Thereafter, butyl cellosolve was added to a solid content of 70% by mass. Then, 48 mass parts of MEK oxime was dripped at the temperature of 50 degreeC to the reaction material, and prepolymer type isocyanate 3 (Pre3) was obtained.

Prepolymer type isocyanate compound 4 (Pre4) was synthesized as follows.
PO8 (trade name: P-2050, manufactured by Kuraray Co., Ltd.): 100 parts by massPolymethylene polyphenylene polyisocyanate (trade name: Millionate MR-200, manufactured by Nippon Polyurethane Industry Co., Ltd.): 76 parts by mass
In a nitrogen atmosphere, the material was heated and reacted at a temperature of 90 ° C. for 2 hours. Thereafter, butyl cellosolve was added to a solid content of 70% by mass. Then, 35 mass parts of MEK oxime was dripped at the temperature of 50 degreeC to the reaction material, and prepolymer type isocyanate 4 (Pre4) was obtained.

Prepolymer type isocyanate compound 5 (Pre5) was synthesized as follows.
PO9 (trade name: L-205AL, manufactured by Daicel Chemical Industries, Ltd.): 100 parts by massPolymethylene polyphenylene polyisocyanate (trade name: Cosmonate M-100, manufactured by Mitsui Chemicals Polyurethanes): 155 parts by mass
In a nitrogen atmosphere, the material was heated and reacted at a temperature of 90 ° C. for 2 hours. Thereafter, butyl cellosolve was added to a solid content of 70% by mass. Then, 38 mass parts of MEK oxime was dripped at the temperature of 50 degreeC to the reaction material, and the prepolymer type isocyanate 5 (Pre5) was obtained.

  Then, although the synthesis method of the amino group containing acrylic resin in the Example and comparative example of this invention is illustrated and demonstrated concretely below, this invention is not limited to these.

<Method for synthesizing amino group-containing acrylic resin>
The following were charged into a four-necked separable flask equipped with a stirrer, a cooler, a thermometer, and a nitrogen inlet tube.
-As a (meth) acrylic acid ester monomer, methyl methacrylate: 2.5 g
・ As amino group-containing monomer, N, N-dimethylaminoethyl (meth) acrylamide: 55.1 g
・ Methyl ethyl ketone as solvent: 50g
-Dimethyl 2,2'-azobis (2-methylpropionate) as a polymerization initiator: 2.0 g
While these were charged and stirred, solution polymerization was carried out for 2 hours under reflux with introduction of nitrogen to obtain a solution of amino group-containing acrylic resin 1 (CCR1).

  In the following, the amino group-containing acrylic resins (CCR2 to CCR14) in Examples and Comparative Examples were synthesized using the above synthesis method, and the following were used.

  The materials shown in Table 4 below were used as starting materials (monomers) of the (meth) acrylic acid ester monomer.

  The materials shown in Table 5 below were used as starting materials for amino group-containing monomers.

Table 6 shows measurement results of raw materials, molar ratios, SP values, and Mn of the respective monomers used for the synthesis. The number of carbon atoms which are also shown in Table 6, the above formula (a), which corresponds to _R 1 to R ₅ in (b).

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

<Method for preparing surface layer-forming coating material>
-Polyol (A), PO7: 100 parts by mass-Polyol (B), PO3: 33 parts by mass-Isocyanate compound, Pre2: 123 parts by mass As a material for the coating material for forming the surface layer, the above components were mixed to form a polyurethane component . Two kinds of polyols having moderately different polarities can control a sea-island type phase separation structure composed of a matrix phase and a domain phase depending on a blend ratio thereof. Therefore, here, the polyurethane soft segment is mainly formed of the polyol (A) in the matrix phase and the polyol (B) in the domain phase.

  Subsequently, 3 parts by mass of CCR8, 20 parts by mass of carbon black (trade name: MA-100, manufactured by Mitsubishi Chemical Corporation) and MEK are added to 100 parts by mass of the solid content of the polyurethane component, and the motor is used for one hour. The mixture was stirred. Subsequently, MEK was further added so that the total solid content ratio was 33% by mass, and the mixture was further stirred with a motor for one hour. Subsequently, the mixed and stirred 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 ml / min, and a dispersion temperature of 15 ° C. for 3 hours. . In this dispersion, glass beads having a diameter φ = 1.5 mm (trade name: DMB503B, manufactured by Hotters Ballotinis) were used. Next, 35 parts by mass of polyurethane fine particles (trade name: Dymic Beads UCN-5070N, manufactured by Dainichi Seika Kogyo Co., Ltd.) as resin particles for adjusting the surface roughness with respect to 100 parts by mass of the solid content of the resin component. Added and dispersed for an additional 30 minutes. Next, this solution is diluted to a solid content of 23% 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. A1.

  Similarly, the surface layer forming paints A2 to A32 and B1 to B6 shown in Table 7 were obtained.

<Measurement of Mn by GPC>
Measurement of Mn of the amino group-containing acrylic resin and polyurethane raw material was performed as follows.
A high-performance liquid chromatographic analyzer (trade name: HLC-8120GPC, manufactured by Tosoh Corporation) in which two GPC columns (trade name: TSKgel SuperHM-M, 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. )

<Measurement of SP value>
The SP values of the amino group-containing acrylic resin and polyurethane raw material were measured as follows.
0.5 g of the sample from which the solvent was completely volatilized was placed in a 30 ml sample tube, 3.0 ml of MEK 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 dripping amount required for the solution to become cloudy was measured. The SP value (δ) was calculated by the following formula from the SP value of each solvent and the volume fraction of MEK required for dissolution of the sample and normal hexane required for causing cloudiness.
δ = δ _MEK × φ _MEK + δ _Hexane × φ _Hexane
φ _MEK = V _MEK / (V _MEK + V _Hexane )
φ _Hexane = V _Hexane / (V _MEK + V _Hexane )

δ _MEK : SP value of MEK (9.3)
δ _Hexane : SP value of normal hexane (7.0)
φ _MEK : Volume fraction of MEK
φ _Hexane : volume fraction of normal hexane
V _MEK : MEK amount required for sample dissolution (3.0 ml)
V _Hexane : The amount of normal hexane dripping required to produce white turbidity (measured value)

<Measurement of ionic strength by TOF-SIMS>
Analysis of the developing roller surface by TOF-SIMS was performed as follows.
・ Measurement model TRIFT IV (trade name: ULVAC-PHI)
・ Primary ion species Au1
・ Primary ion current (DC) 600 [pA]
・ Primary ion energy 30 [kV]
Sample potential +3.0 to +3.2 [kV]
・ Secondary ion detection mode Positive
・ Measurement degree of vacuum: 1 × 10 ⁻⁸ [Pa]
・ Measurement area 100μm × 100μm
・ Measurement integration time 9000 seconds ・ Detected mass range 1.5 to 1850 amu
In the measurement region thus mapped, the matrix phase and the domain phase were separated, and the total ionic strength and the ionic strength derived from the amino group were calculated. An ion derived from an amino group is observed as an ion such as [C ₂ H ₄ N], [C ₃ H ₈ N], and [C ₄ H ₁₀ N] when N (CH ₃ ) is included as an amino group, for example. The

<Measurement of current value>
An apparatus as shown in FIG. 5 was used as the current value measuring apparatus. The developing roller 1 was brought into contact with a metal roller 37 having a diameter of 50 mm by applying a load of 4.9 N to both ends of the shaft core of the developing roller. The developing roller 1 was driven and rotated by driving and rotating the metal roller 37 by a driving means (not shown) at a surface speed of 50 mm / sec. Next, a voltage of +50 V was applied from the high-voltage power supply 38 to the shaft core body of the developing roller. A potential difference between both ends of a resistor 39 having a known electrical resistance disposed between the metal roller 37 and the ground is measured for 5 seconds using a digital multimeter 40 (trade name: 189TRUE RMS MULTITIMER, manufactured by FLUKE). did. From the measured average value of the potential difference and the electrical resistance of the resistor, the value of the current flowing through the metal roller via the developing roller was determined.

Example 1
Surface treatment was performed by performing excimer UV treatment on the elastic layer roller A1. While rotating at 30 rpm with the shaft core of the elastic layer roller A1 as the rotation axis, ultraviolet light with a wavelength of 172 nm is applied with a capillary excimer lamp (trade name: capillary excimer UV irradiation unit, manufactured by Harrison Toshiba Lighting Co., Ltd.) with an integrated light amount of 150 mJ / cm ² Irradiation was performed as follows. The distance between the elastic layer surface of the elastic layer roller A1 and the excimer lamp at the time of irradiation was 2 mm. Then, the coating film of the coating material for surface layer formation was formed by applying the coating material A1 for surface layer formation using the dip coating method.

  In forming the surface layer, 250 cc of the surface layer forming coating material A1 maintained at a liquid temperature of 23 ° C. is poured from below the cylinder having an inner diameter of 32 mm and a length of 300 mm, and the liquid overflowing from the upper end of the cylinder is poured. It was circulated again below the cylinder. The elastic layer roller A1 is immersed in the surface layer forming coating material A1 in the cylinder at a dipping speed of 100 mm / s, stopped for 10 seconds, and then elastic under the conditions of an initial speed of 300 mm / s and a final speed of 200 mm / s. The layer roller A1 was pulled up and naturally dried for 60 minutes. Next, the coating film of the coating material for forming the surface layer was cured by heat treatment at a temperature of 140 ° C. for 2 hours, so that the developing roller A1 of Example 1 was produced.

In order to identify the matrix phase and the domain phase of the obtained developing roller A1, mapping was performed by a Fourier transform-infrared absorption (FT-IR) method. 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: 1.0 cm / s. A thin slice on the surface was cut out from the developing roller A1 with a microtome, and an amino group-containing acrylic resin was extracted with toluene, and then mapping was performed. As a result, a spectrum due to the urethane group (1710 cm ⁻¹ ) was confirmed over the entire visual field. Moreover, the strong spectrum resulting from an ester group (1200cm < ^-1 >) was confirmed in the substantially whole field of view. Furthermore, a region having a strong spectrum due to the ether group (1100 cm ⁻¹ ) and an extremely small spectrum due to the ester group was confirmed, and such a region has a circle equivalent diameter of about 5 μm to 10 μm. It was confirmed that they were scattered. Therefore, it was identified that the matrix phase of the developing roller A1 is a polyurethane having a soft segment derived from the polyol (A) (PO7) and the domain phase derived from the polyol (B) (PO3).

In the measurement of ionic strength by TOF-SIMS, σ _{M, A} / σ _{M, T} of the developing roller A1 is 5.4 × 10 ⁻⁶ , (σ _{D, A} / σ _{D, T} ) / (σ _{M, A} / Σ _{M, T} ) was 4.4 × 10 ³ . Each value satisfied the above formulas (A) and (B), and the uneven distribution of the amino group-containing acrylic resin in the domain phase was confirmed.
The current value of the developing roller A1 was 154 μA.
Further, the following image evaluation was performed on the developing roller A1. Various evaluation results are shown in Table 8.

(Examples 2-32)
Developing rollers A2 to A32 were produced in the same manner as in Example 1 except that the surface layer forming coating material A1 of Example 1 was changed to A2 to A32.
Evaluation of various characteristics and image evaluation of the developing rollers A2 to A32 in Examples 2 to 32 were performed in the same manner as the developing roller A1 of Example 1. Table 8 shows the evaluation results of the developing rollers A2 to A32.

(Comparative Examples 1-6)
Developing rollers B1 to B6 were produced in the same manner as in Example 1 except that the surface layer forming coating material A1 of Example 1 was changed to B1 to B6.
Evaluation of various characteristics and image evaluation of the developing rollers B1 to B6 in Comparative Examples 1 to 6 were performed in the same manner as the developing roller A1 of Example 1. Table 9 shows the evaluation results of the developing rollers B1 to B6.

  Subsequently, the image evaluation method in the examples and comparative examples of the present invention will be specifically described below.

[Overview of laser printer remodeling machine]
The laser printer used for the image evaluation of the present invention is one in which the output speed of the recording medium of a commercially available laser printer (trade name: HP Color LaserJet CP4525dn Printer, manufactured by Hured Packard) is modified to 55 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 developing 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]
A new developing roller was incorporated into a new process cartridge (trade name: CE260X, color: black, manufactured by Hured Packard), and the process cartridge was left in an environment of a temperature of 35 ° C. and a humidity of 85% RH for 48 hours. Then, in the same environment, the process cartridge was installed in the laser printer remodeling machine, and 10,000 images were continuously 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 non-printing range (reference) and the printing range (white solid image portion) is measured, and the white solid image portion relative to the reference The amount of decrease in reflectance (%) was defined as “fogging”. This fog was evaluated according to the following criteria. Tables 8 and 9 show the results of the developing rollers produced in each Example and Comparative Example.
A: The fog is less than 1%.
B: The fog is 1% or more and less than 2%.
C: The fog is 2% or more and less than 3%.
D: The fog is 3% or more.

[Image evaluation of streak / distortion after long-term storage in high temperature and high humidity environment]
A new developing roller was incorporated into a new process cartridge (trade name: CE260X, color: black, manufactured by Hured Packard), and the electrophotographic process cartridge was left in an environment of a temperature of 40 ° C. and a humidity of 95% RH for 30 days. Thereafter, it was further left for 24 hours in an environment of a temperature of 23 ° C. and a humidity of 50% RH. Then, in the same environment, the process cartridge was incorporated into the laser printer remodeling machine, and 10 halftone images were output. The halftone image and the distortion amount of the developing roller immediately after the image evaluation were measured, and the image layer adverse effect resulting from the deformation of the developing roller was evaluated under the following evaluation conditions. The distortion amount on the developing roller surface was measured using a laser displacement sensor (trade name: LT-9500V, manufactured by Keyence Corporation). A laser displacement sensor is installed in the vertical direction with respect to the surface of the developing roller from which the toner has been removed by air blow, and the developing roller is rotated at an arbitrary number of rotations to read the circumferential displacement of the developing roller surface, and the amount of distortion It was measured. The amount of distortion was measured at five points with a pitch of 43 mm in the longitudinal direction of the developing roller, and the average value of the five points was used. Tables 8 and 9 show the results of the developing rollers produced in each Example and Comparative Example.
A: In a halftone image, no streak-like image layer detrimental effects resulting from deformation of the developing roller are confirmed. Further, the amount of distortion on the surface of the developing roller is less than 1 μm.
B: In the halftone image, a streak-like image layer detrimental effect resulting from the deformation of the developing roller is very slightly confirmed. Further, the amount of distortion on the surface of the developing roller at a position corresponding to the streak is 1 μm or more and less than 3 μm.
C: In a halftone image, streak-like image layer detrimental effects resulting from deformation of the developing roller are confirmed. Further, the amount of distortion on the surface of the developing roller at a position corresponding to the streak is 3 μm or more and less than 6 μm.
D: In a halftone image, significant streak-like image layer detrimental effects resulting from deformation of the developing roller are confirmed. Further, the amount of distortion on the surface of the developing roller at the position corresponding to the streak is 6 μm or more.

[Image evaluation of toner fusion in low temperature and low humidity environment]
A new developing roller was incorporated into a new process cartridge (trade name: CE263A, color: magenta, manufactured by Hured Packard), and the process cartridge was left in an environment of temperature 0 ° C. and humidity 15% 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 1%. When the toner is fused to the surface of the developing roller, fog due to a decrease in frictional charging property imparted to the toner becomes apparent on the image. Therefore, evaluation of toner fusion in a low-temperature and low-humidity environment measures the number of output sheets in which fog exceeding 3% is observed in a white solid image portion, and evaluates the appearance of the developing roller after image evaluation according to the following evaluation criteria. I went there. In addition, a reflection densitometer (trade name: TC-6DS / A, manufactured by Tokyo Denshoku Co., Ltd.) was used to measure the reflectance of the non-printing range (reference) and the printing range (white solid image portion) every 1000 sheets of output. . The amount of decrease (%) in the reflectance of the white solid image portion with respect to the reference was defined as “fog”. Further, when the number of continuous prints exceeded 10,000, the developing roller was incorporated into a new process cartridge, and evaluation of toner fusion was continuously performed. Before the development roller was observed, the appearance was evaluated by removing the toner that did not contribute to toner fusion by air blowing. Tables 8 and 9 show the results of the developing rollers produced in each Example and Comparative Example.
A: Fog of 3% or more is not confirmed even with 15000 continuous prints. Further, in the observation of the developing roller after the image evaluation, the toner fused product is not confirmed or is confirmed very slightly.
B: Fog of 3% or more was confirmed on 12,000 or more continuous prints and less than 15,000 sheets. Further, a slight amount of toner fusion product is confirmed in the observation of the developing roller after image evaluation.
C: A fog of 3% or more was confirmed on 8000 to less than 12,000 continuous prints. Furthermore, a toner fused product is confirmed in the observation of the developing roller after the image evaluation.
D: Fog of 3% or more was confirmed on less than 8000 continuous prints. Further, a remarkable toner fusion product is confirmed in observation of the developing roller after image evaluation.

[Ghost image evaluation under low temperature and low humidity]
The ghost evaluation was performed after printing 3000 sheets in the same environment as the image evaluation of the toner fusion. An image in which solid black marks (squares and circles) are arranged at equal intervals on a white background is output in an area corresponding to one rotation of the developing roller at the end of the image, and a halftone image is output in other areas. The degree of appearance of the ghost of the mark on the tone image was evaluated according to the following criteria. A: No difference in shading is observed.
B: A slight shading difference can be confirmed depending on the monitoring angle.
C: A ghost can be confirmed for one rotation of the developing roller.
D: A ghost can be clearly confirmed for one rotation of the developing roller.
E: It can be confirmed over two rotations of the developing roller.

  As is apparent from Tables 8 and 9, in the developing roller of the present invention, fog and streaks / distortions after long-term storage in a high-temperature and high-humidity environment, and toner fusion on the developing roller surface in a low-temperature and low-humidity environment Wear and ghost suppression are achieved at the same time.

  It was confirmed that fog was deteriorated in the developing roller B1 produced in Comparative Example 1. This is because the developing roller B1 does not contain an amino group-containing acrylic resin, and the amount of triboelectric charge to the toner is insufficient under the environment of the present invention.

  In the developing roller B2 produced in Comparative Example 2, toner fusion was deteriorated. In the developing roller B2, amino group-containing acrylic resin is unevenly distributed in the matrix phase, and the triboelectric chargeability of the matrix phase is increased. As a result, it is considered that the toner strongly adhered to the matrix phase occupying a large area on the surface of the developing roller. As a result, toner scraping by the toner supply roller becomes insufficient, and the toner fusing deteriorates due to repeated rubbing of the toner. Further, the ghost deteriorated in the developing roller B2. This is because the resistance of the surface layer is greatly increased by the amino group-containing acrylic resin being unevenly distributed in the matrix phase that continuously exists from the surface of the developing roller to the elastic layer in the surface layer.

  The development roller B3 produced in Comparative Example 3 was confirmed to be deteriorated in ghost. This is because the resistance greatly increases because the surface layer does not contain carbon black. In addition, toner fusing deteriorated. This is because the presence of carbon black increases the tackiness of the surface layer and increases the adhesion between the surface layer and the toner.

  In the developing roller B4 produced in Comparative Example 4, the stripe / distortion amount deteriorated. In the developing roller B4, many amino group-containing acrylic resins themselves exist in the surface layer as domain phases. The amino group-containing acrylic resin has very poor adhesion to polyurethane and increases the compression set of the surface layer.

  The developing roller B5 produced in Comparative Example 5 was confirmed to have deteriorated toner fusion. The developing roller B5 has a structure in which an amino group-containing acrylic resin is contained in the entire surface layer of polyurethane which is not a sea-island type phase separation structure. As a result, the toner adhered strongly to the entire surface of the developing roller, and the toner fusing deteriorated. Further, the ghost deteriorated in the developing roller B5. This is because the resistance of the developing roller is greatly increased because the entire surface layer contains the amino group-containing acrylic resin.

  In the developing roller B6 produced in Comparative Example 6, the stripe / distortion amount deteriorated. The developing roller B6 is obtained by adding a large amount of carbon black to the developing roller B5 in order to make the current value of the developing roller appropriate. This confirmed that the ghost was improved. On the other hand, since a large amount of polyurethane and carbon black having poor adhesiveness were added, the compression set of the surface layer increased and the streak / strain amount deteriorated.

  From the above, by satisfying the conditions stipulated in the present invention, fog reduction and development roller deformation suppression after long-term storage in a high temperature and high humidity environment, and toner fusion to the developing roller surface in a low temperature and low humidity environment Obviously, both prevention and ghost suppression were compatible.

3 Elastic layer 4 Surface layer 11 Matrix phase 12 Domain phase

Claims (6)

A developing member comprising: a shaft core having a conductive surface; a conductive elastic layer covering a peripheral surface of the shaft core; and a conductive surface layer covering a peripheral surface of the elastic layer. There,
The surface layer contains polyurethane, carbon black, and an acrylic resin having an amino group in the molecule,
The surface layer has a sea-island type phase separation structure composed of a matrix phase containing polyurethane and a domain phase containing polyurethane,
A developing member, wherein the acrylic resin is unevenly distributed in the domain phase. The developing member according to claim 1, wherein the acrylic resin having an amino group has a structure represented by the following formulas (a) and (b).

In the above formulas (a) and (b), R ₁ and R ₅ are hydrogen atoms or methyl groups, R ₂ is an alkylene group having 2 to 4 carbon atoms, and R ₃ and R ₄ are alkyl groups having 1 to 4 carbon atoms. , R ₆ represents an alkyl group having 1 to 8 carbon atoms.   The developing member according to claim 1, wherein the polyurethane contained in the matrix phase contains an ester group in the molecule, and the polyurethane contained in the domain phase contains an ether group in the molecule. The polyurethane contained in the matrix phase includes at least one structure selected from the following formulas (c) and (d) between two adjacent urethane groups, and the polyurethane contained in the domain phase is adjacent to each other. The development according to any one of claims 1 to 3, comprising at least one structure selected from the following formulas (f), (g) and (h) and a structure (e) between two urethane groups. Element.

  5. A process cartridge that is detachably attached to an electrophotographic image forming apparatus main body, the process cartridge including at least a developing member, a developing blade, and a toner container, and the developing member is any one of claims 1 to 4. A process cartridge according to claim 1.   An electrophotographic image forming apparatus having a photoconductor and a developing member disposed in contact with the photoconductor, wherein the developing member is the developing member according to any one of claims 1 to 4. An electrophotographic image forming apparatus.

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