JP2012103581A - Developing roller, electrophotographic processing cartridge, and electrophotographic image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing roller capable of restraining occurrence of binding even when images are output at a high speed for a long period of time and capable of restraining initial fixing of toner and fusion of toner when image output is carried out repeatedly at a low temperature and a low humidity.SOLUTION: In the developing roller having a shaft core body and at least one resin layer provided around the shaft core body, the outermost layer of the developing roller contains a polyurethane resin (A) as a binding resin for forming a continuous layer and polyurethane resin particles (B) dispersed in the polyurethane resin (A). If the loss tangents (tanδ) of the polyurethane resin (A) and polyurethane resin particles (B), obtained at a measurement temperature T(T=-20°C to 40°C) and at a frequency of 10 Hz are defined as tanδ(A) and tanδ(B) respectively, the developing roller satisfies the following expressions: (1) 0.40≤tanδ(B)≤1.10 and (2) 0.30≤tanδ(B)-tanδ(A)≤0.70.

Description

  The present invention relates to a developing roller used in contact with a photoreceptor in an electrophotographic image forming apparatus, a method for manufacturing the same, and the like.

  In an electrophotographic image forming apparatus employing a contact development system, toner is supplied onto the surface of the developing roller by an elastic roller provided in contact with the developing roller. Next, excess toner on the surface of the developing roller is removed by the toner regulating member to form a toner layer in a thin film on the developing roller, and at the same time, a predetermined amount of positive or negative triboelectric charge is given to the toner particles by rubbing. Further, the toner positively or negatively frictionally charged by the rotation of the developing roller is conveyed, and the toner is attached to the electrostatic image on the surface of the photoreceptor provided in contact with the developing roller, and development is performed. As such a developing roller, a roller in which a resin layer is provided around the conductive shaft core and a surface layer is provided on the outer periphery as necessary is used.

  In addition, space-saving and low-cost electrophotographic image forming apparatuses have become widespread, and in recent years, the usage environment has greatly fluctuated. However, it may be very difficult to maintain image quality in extreme environments such as a high temperature and high humidity environment and a low temperature and low humidity environment. Specifically, in a high temperature and high humidity environment, the developing roller surface layer and toner are softened, and tackiness (surface adhesiveness) is increased. This phenomenon occurs in the early stage of image output. By outputting several to several tens of images, toner fixation tends to disappear due to friction with the contact member. be called. On the other hand, in a low-temperature and low-humidity environment, when the hardness of the developing roller surface layer increases, the stress applied to the toner increases, and the toner is filmed (fused) on the developing roller surface layer before the cartridge life was there. As a countermeasure against such initial toner fixation, in Patent Document 1, inorganic particles having a property of releasing properties with respect to the toner are sprinkled on and adhered to the surface of the elastic layer to have good chargeability with respect to the toner. A developing roller with an elastic layer that suppresses initial toner adhesion has been proposed.

Japanese Patent Laid-Open No. 09-62086

  However, in the developing roller described in Patent Document 1, toner fusion due to toner deterioration may occur due to image output over a long period of time in a low temperature and low humidity environment.

  An object of the present invention is to provide a developing roller capable of suppressing initial toner fixation in a high-temperature and high-humidity environment and suppressing toner fusion on the surface layer of the developing roller when a repeated image is output under low temperature and low humidity. It is to provide. It is another object of the present invention to provide a developing roller capable of forming a high-quality image without banding even when an image is output at a high speed for a long period of time. It is another object of the present invention to provide a method for producing such a developing roller, an electrophotographic process cartridge having high image quality and high durability, and an electrophotographic image forming apparatus using such a developing roller.

  In view of the above problems, the present inventors have attempted to improve image defects such as image defects and banding caused by initial toner fixation in a high temperature and high humidity environment and toner fusion in a low temperature and low humidity environment. As a result, the outermost surface layer of the developing roller is composed of a matrix resin as a binder resin and resin particles dispersed in the matrix resin, and by optimizing the correlation between the resin material and the viscoelastic characteristics of the above, I found that I could achieve my objective.

That is, the developing roller according to the present invention is a developing roller having a shaft core body and at least one resin layer provided around the shaft core body, and the outermost surface layer of the developing roller is a binder resin. The polyurethane resin (A) and the polyurethane resin particles (B) dispersed in the polyurethane resin (A) are contained in the polyurethane resin (A) and the polyurethane resin particles (B). = −20 ° C. to 40 ° C.), loss tangent (tan δ) measured at a frequency of 10 Hz is defined as tan δ (A) and tan δ (B), respectively, and satisfies the following formulas (1) and (2) It is characterized by.
0.40 ≦ tan δ (B) ≦ 1.10 (1)
0.30 ≦ tan δ (B) −tan δ (A) ≦ 0.70 Equation (2)

  The present invention has a developing roller that supplies toner to the surface of a photoreceptor carrying an electrostatic latent image to develop the electrostatic latent image into a toner image, and is detachably attached to the electrophotographic image forming apparatus. The electrophotographic apparatus process cartridge is characterized in that the developing roller is the developing roller.

  According to another aspect of the present invention, there is provided an electrophotographic apparatus having a developing roller that supplies a toner to the surface of a photoreceptor carrying an electrostatic latent image to develop the electrostatic latent image into a toner image, wherein the developing roller is the developing roller. The present invention relates to an electrophotographic image forming apparatus.

  According to the present invention, (1) generation of banding can be suppressed even if image output is performed at high speed over a long period of time, and (2) occurrence of initial toner fixation on the surface is suppressed, and a stable image can be obtained. It is possible to provide a developing roller that can be formed, and (3) can suppress image detrimental effects caused by toner fusion when an image is repeatedly output at low temperature and low humidity. Further, it is possible to provide a process cartridge and an electrophotographic image forming apparatus capable of forming an image with a long life and high image quality.

It is sectional drawing of an example of the developing roller of this invention whose resin layer is a multilayer structure. It is a schematic diagram of an example of the liquid circulation type dip coating apparatus used for intermediate | middle layer formation. 1 is a schematic configuration diagram of an example of an electrophotographic process cartridge of the present invention. 1 is a schematic configuration diagram of an example of an electrophotographic image forming apparatus of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the developing roller 1 of the present invention, as shown in FIG. 1, a resin layer 3 is fixed to the outer peripheral surface of a cylindrical or hollow cylindrical conductive shaft core 2. When the developing roller has a single layer structure, the resin layer 3 becomes the outermost surface layer 4. The resin layer 3 may have a multilayer structure with different materials and compositions. In this case, in the present invention, the polyurethane resin (A) as a binder resin that forms a continuous layer on the outermost surface layer 4 and the polyurethane resin particles (B) dispersed in the polyurethane resin (A) Contained.

<Conductive shaft core 2>
The conductive shaft core 2 used in the developing roller of the present invention is an electrode that supports at least one resin layer 3 in the upper layer and can transport the toner to the photoreceptor, and an electrode that can move the charged toner to the photoreceptor. What is necessary is just to have the electroconductivity to obtain.

<Resin layer 3>
The developing roller of the present invention has at least one or more resin layers 3 on the outer peripheral surface of the conductive shaft core 2 as shown in FIG. And it contains the polyurethane resin (A) as a binder resin that forms a layer continuous with the outermost surface layer, and the polyurethane resin particles (B) dispersed in the polyurethane resin (A). Moreover, the range of the loss tangent (tanδ) required for the polyurethane resin (A) and the polyurethane resin particles (B) in the present invention is different.

  Here, the loss tangent (tan δ) will be described. In general, when a viscoelastic body such as rubber or resin material is deformed by applying stress, most of the applied stress is stored as energy of internal deformation and becomes a driving force for restoration when the stress is removed. However, a part of the energy is consumed due to the friction of the molecular structure accompanying the strain at the time of applying the stress, and thus converted into thermal energy. Loss tangent (tan δ) is used as a value indicating an index of the internal friction. Accordingly, rubber and resin materials having a high tan δ have been conventionally used as a means for dissipating mechanical energy, that is, for absorbing shock.

  However, rubbers and resin materials having a high tan δ generally exhibit properties that are highly viscous or easily plastically deformed. Therefore, when used for a rubbing member such as the developing roller of the present invention, the adverse effect of tackiness is stronger than the dissipation of mechanical energy, and banding occurs due to the stick-slip phenomenon at the time of rubbing with the contact member. There was a case. Conversely, rubbers and resin materials with low tan δ generally have low viscosity and are excellent in toner adhesion resistance. On the other hand, since mechanical energy is difficult to dissipate, especially when image output is performed at high speed for a long period of time, the mechanical energy transmission path continues to be heavily loaded, and banding due to gear wear deteriorates. There was a case.

  Furthermore, the value of tan δ in rubber or resin material may vary greatly depending on the measurement frequency and temperature. Dissipation of mechanical energy in the developing roller of the present invention is due to the fact that the rotational vibration component generated in the drive system is mainly converted into heat in the elastic member. Therefore, when measuring the tan δ value, it is necessary to take into account concepts such as the frequency characteristics and transfer function of the drive system, and to measure under a frequency condition in accordance with the excitation frequency of the generated vibration.

  Further, tan δ of rubber or resin material shows a feature that peaks at the glass transition temperature. Therefore, conventionally, a rubber or resin material having a glass transition temperature near the use temperature has been used as a vibration damping material. Further, as a tan δ control method other than the glass transition temperature control, a method of containing a large amount of a component that does not contribute to crosslinking of the main rubber material such as a softening agent such as paraffinic oil has been used. However, the developing roller in the present invention is intended to form a uniform and high-quality image in a wide temperature range. Therefore, when a rubber material having a glass transition temperature is used within the operating temperature range, the hardness of the rubber material is too high, so that the toner on the surface layer of the developing roller when an image is repeatedly output under low temperature and low humidity Fusion may deteriorate. Further, when a softening agent such as paraffinic oil is used, it may bleed when stored for a long time in a high-temperature environment, and the initial fixation of the toner may deteriorate. As described above, suppression of toner fusion under low temperature and low humidity and toner initial fixation under high temperature and high humidity tends to be in a trade-off relationship depending on the value of tan δ of rubber or resin material. That is, in order to exhibit the effect of the present invention, it is important to design the structure of the outermost surface layer of the developing roller from the viewpoint of functional separation while considering the temperature dependence of tan δ.

  In view of the above technical background, the present inventors have intensively studied, and as a result, the outermost surface layer of the developing roller in the present invention is characterized by the polyurethane resin particles (A) characteristically exhibiting high tan δ in the polyurethane resin (A) as the matrix portion. It has been found that it is effective that B) is dispersed. Furthermore, the tan δ value of the polyurethane resin particles (B) measured at a measurement temperature T (T = −20 ° C. to 40 ° C.) and a frequency of 10 Hz is higher than the tan δ value of the polyurethane resin (A). It was found that the effects of the present invention can be exhibited by being in the range.

Here, tan δ (A) and tan δ (B) indicate the tan δ values of the polyurethane resin (A) and the polyurethane resin particles (B), respectively. In the present invention, tan δ (B) measured within a temperature range where the frequency is 10 Hz and the measurement temperature T is −20 ° C. to 40 ° C. is set to the following range.
0.40 ≦ tan δ (B) ≦ 1.10 (1)
In the present invention, tan δ (A) and tan δ (B) are defined as the highest value and the lowest value, respectively, among the values measured within the measurement temperature range of −20 ° C. to 40 ° C. The value of tan δ (B) is at a very high level as compared with resin particles generally used for electrophotographic rubber rollers. As in the present invention, the presence of the polyurethane resin particles (B) exhibiting the above characteristics in the outermost surface layer can effectively dissipate mechanical energy due to friction with the contact member when the developing roller is driven. . Furthermore, since it is possible to efficiently convert the vibration component in the rotational direction into thermal energy, even if an image is output over a long period of time at high speed, wear of gears that are transmission paths of mechanical energy Can be suppressed. Further, tan δ tends to continuously decrease as the temperature changes with the glass transition temperature of rubber or resin material as a boundary. However, by setting the tan δ of the polyurethane resin particles (B) to the above value, banding can be effectively suppressed even if image output is performed over a long period of time in any environment from low temperature and low humidity to high temperature and high humidity. can do. On the other hand, if the tan δ (B) of the polyurethane resin particles (B) is less than 0.40, the mechanical energy dissipation is insufficient, the wear of gears proceeds, and banding is likely to occur. is there. On the other hand, if the ratio is larger than 1.10, initial toner fixation may easily occur due to an increase in the contribution of rubber viscosity. Furthermore, due to an increase in surface tackiness, a stick-slip phenomenon may occur during rubbing with the contact member, and banding may easily occur.

Furthermore, in the present invention, the difference between tan δ (B) measured at a frequency of 10 Hz and a measurement temperature T within a temperature range of −20 ° C. to 40 ° C. and tan δ (A) is set to the following range. .
0.30 ≦ tan δ (B) −tan δ (A) ≦ 0.70 Equation (2)
This value is related to the difference in relative viscoelastic properties between the urethane resin (A) and the urethane resin particles (B) as a matrix, and indicates an index of functional separation between the two. In the present invention, tan δ (B) -tan δ (A) is defined as the lowest value measured at the same temperature within the measurement temperature range of −20 ° C. to 40 ° C. As described above, a sliding member such as the developing roller of the present invention may have difficulty in achieving both image performance under low temperature and low humidity and high temperature and high humidity depending on the value of tan δ. As a result of intensive studies, the present inventors have set tan δ (B) -tan δ (A) within the above range so that the image is repeatedly applied to the surface of the developing roller when the image is repeatedly output under initial toner fixation and low temperature and low humidity. It was found that all of toner fusion and suppression of banding can be achieved simultaneously. In other words, by dispersing resin particles with a characteristically high tan δ in a matrix with a low tan δ, it is possible to achieve both the characteristic performance related to image formation that tends to have a trade-off relationship depending on the value of the viscoelastic property (tan δ). I found it. The mechanism by which the effects of the present invention can be exhibited by taking the above-described configuration has not been completely elucidated, but is estimated as follows. That is, by making the viscoelastic characteristics of the polyurethane resin (A) and the polyurethane resin particles (B) as the matrix different, the natural frequencies of the two differ. When the developing roller is driven, rubbing with the contact member is repeated. However, since both have different natural frequencies, resonance in the rotating direction of the developing roller is reduced, and vibration components in the rotating direction can be suppressed. It is thought that it was made. If tan δ (B) −tan δ (A) is less than 0.30, the efficient dissipation of mechanical energy is insufficient, and image defects such as banding are likely to occur. On the other hand, if the ratio is larger than 0.70, initial toner fixation or toner fusion on the surface layer of the developing roller when an image is repeatedly output under low temperature and low humidity may easily occur. Further, the vibration frequency of vibration generated during actual driving varies depending on factors such as the rotation speed of the developing roller, the peripheral speed difference with the drum that is in contact with the outermost layer, and the configuration of the outermost surface layer. Therefore, tan δ in the present invention is a value at 10 Hz, which is near the average value of the excitation frequency in the actual machine.

  Furthermore, it is a very important point that both are the same type of resin material in order to exhibit the effects of the present invention. Since both are resins of the same system, the interfacial affinity between the polyurethane resin (A) and the polyurethane resin particles (B) as a matrix is very good, and the mechanical energy is efficiently absorbed when the developing roller is driven. To be done. Furthermore, even when mechanical energy is converted into energy such as thermal energy and dissipated, thermal energy transfer is good, effectively dissipating mechanical energy and at a high level. This contributes to the suppression of banding. In addition, the polyurethane resin particles (B) with relatively high viscosity (tan δ) are dispersed in the highly elastic polyurethane resin (A) and are present in the interior, thereby suppressing the increase in tackiness on the outermost surface to the maximum. can do.

  In addition, the polyurethane resin here is not a name indicating a polymer having a single composition, but is a general term for polymers including a urethane bond, and is composed of two segments, a hard segment and a soft segment. The hard segment is composed of segments containing bonds such as urethane bonds, allophanate bonds, and biuret bonds. The soft segment is composed of a segment having a functional group such as an ether group, an ester group, a carboxyl group, an alkyl group, or an alkenyl group. Polyurethanes are generally classified into polyester polyurethane, polyether polyurethane, polycarbonate polyurethane, acrylic polyurethane, and polyolefin polyurethane according to the chemical bond species that form the soft segment.

  The number average particle diameter of the polyurethane resin particles (B) in the present invention is preferably 5 μm or more and 50 μm or less. By being 5 μm or more, the polyurethane resin particles (B) are not excessively aggregated, mechanical energy is efficiently dissipated, and banding can be suppressed. Further, when the thickness is 50 μm or less, an excessive increase in surface tackiness can be suppressed, and initial toner adhesion can be suppressed. Furthermore, banding due to stick-slip phenomenon at the time of rubbing with the contact member can be suppressed. The number average particle diameter of the polyurethane resin particles was arbitrarily extracted from a plurality of cut surfaces by cutting the resin layer 3 and the outermost surface layer 4 of the developing roller 1 with a razor blade in a direction perpendicular to the conductive shaft core 2. The diameter of 1000 particles is measured using an optical microscope and defined as the arithmetic average value of the measured values. Further, when the shape is not true spherical and the particle diameter is not specified uniformly, the longest diameter and the shortest diameter are measured, respectively, and the arithmetic average value thereof is taken as the particle diameter of the particle.

  Moreover, it is preferable that the surface of the polyurethane resin particles (B) in the present invention is partially covered with inorganic fine particles containing at least one element selected from silicon, titanium, and aluminum. Typical examples include substances such as silica, titanium oxide, aluminum oxide, and hydrotalcite. These inorganic fine particles may be subjected to a surface treatment such as hydrophobization or hydrophilization as necessary. In particular, silica can be suitably used because it is easy to surface-treat and can easily control the affinity with the polyurethane resin particles (B). One kind or a plurality of kinds of these inorganic fine particles may be coated on the polyurethane resin particles (B). The average primary particle diameter of the inorganic fine particles is preferably 5 nm or more and 200 nm or less because the covering property to the polyurethane resin particles (B) is appropriate. Furthermore, since it can coat effectively by adding a small amount, it is more preferably 5 nm or more and 50 nm or less. These average primary particle diameters can be observed with a transmission electron microscope (TEM) and measured in the same manner as the polyurethane resin particles (B). Further, it is possible to determine whether or not these inorganic fine particles are any element of silicon, titanium, and aluminum by a known elemental analysis method such as EDAX or ESCA.

  Since the surface is coated with the inorganic fine particles, the aggregation of the polyurethane resin particles (B) is suppressed, and the dispersibility in the polyurethane resin (A) is improved, so that the mechanical energy is more efficient. Dissipated and contributes to suppression of banding. In addition, since the tackiness of the surface of the polyurethane resin particles (B) can be suppressed, even when the polyurethane resin particles (B) are exposed on the outermost surface, the increase in surface tackiness is suppressed and initial toner adhesion is suppressed. can do.

  Moreover, it is preferable that content of the polyurethane resin particle (B) in this invention is 5 to 60 mass parts with respect to 100 mass parts of resin components of a polyurethane resin (A). When the content of the polyurethane resin particles (B) is 5 parts by mass or more, mechanical energy can be sufficiently dissipated and banding can be suppressed. Moreover, by being 60 mass parts or less, an excessive raise of surface tackiness can be suppressed and initial toner adhesion can be suppressed. Furthermore, banding due to stick-slip phenomenon at the time of rubbing with the contact member can be suppressed.

  The tan δ of the polyurethane resin particles (B) in the present invention can be adjusted by controlling the blending amount of the conductive agent, filler, and plasticizer and optimizing the blending of the polyurethane main raw material. . Specifically, a plurality of materials having different glass transition temperatures are blended, and the distribution of the distance between crosslinks is broadened to continuously change the glass transition temperature in a temperature range of −20 ° C. to 40 ° C. Thus, tan δ can be controlled over a wide temperature range. Furthermore, by selecting the molecular weight of the main raw material and controlling the isocyanate index, in the network structure formed after crosslinking, a molecular chain with one end unreacted is formed, and tan δ can be controlled. . The isocyanate index indicates a 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 polyhydroxy compound component. In the present invention, the hydroxy compound component refers to a polyol and a short chain diol. By such a molecular chain in which one end forms a cross-link and the other end is unreacted behaves like a softening agent, it is possible to easily achieve both increase in tan δ and suppression of initial sticking by bleed. . Furthermore, tan δ can also be controlled by the length (molecular weight) of the molecular chain in which one end is unreacted and the abundance. By controlling the tan δ of the polyurethane resin particles (B) by the above-described method, it is possible to easily achieve both suppression of increase in surface tackiness and suppression of banding due to bleeding of unreacted substances.

  Examples of the main raw material for the polyurethane resin particles (B) include those obtained by reacting a mixture of a polyhydroxy compound such as a polyol or a short-chain diol with an isocyanate compound. Although the polyol in this invention is not specifically limited, The following are mentioned as an example. Polycarbonate polyol, acrylic polyol, caprolactone polyol, polyether polyol, polyester polyol, polyolefin polyol and mixtures thereof. In addition, prepolymer polyols obtained by re-elongating these polyols with isocyanate can also be suitably used.

  For example, as a polyether polyol compound, polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene polyoxytetramethylene glycol, polyoxypropylene polyoxytetramethylene glycol, polyoxyethylene polyoxypropylene polyoxytetramethylene glycol, THF and A neopentyl glycol copolymer (PTXG) may be mentioned.

  Although it does not specifically limit as a polyester polyol, The polyester polyol obtained by direct esterification reaction and 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 is obtained by dehydrating and condensing a polybasic acid and a polyhydric alcohol as raw materials.

  The polybasic acid is not particularly limited, but 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, trimethylolpropane, trimethylolethane, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol 1,9-nonanediol, 2-methyl-1,3-propanediol and 2,4-diethyl-1,5-pentanediol can be mentioned as examples.
The polycaprolactone polyol is not particularly limited, but polycaprolactone polyol obtained by ring-opening polymerization reaction using ε-caprolactone as a raw material, or prepolymer polyhydroxy synthesized by prepolymerizing polycaprolactone polyol. Examples are compounds.

  Moreover, the optimal number average molecular weight (Mn) of the polyol in this invention changes with the kind of isocyanate used as a hardening | curing agent, and the propriety of urethane prepolymerization. If the polyol does not contain a urethane group in the structure, it is preferably in the range of 500 ≦ Mn ≦ 8000. When Mn is 500 or more, an excessive increase in the crosslinking density of the urethane resin particles (B) can be suppressed, so that tan δ necessary for manifesting the effects of the present invention can be easily controlled. On the other hand, when Mn is 8000 or less, it is easy for the urethane resin particles (B) to have a glass transition temperature in the vicinity of a temperature range of −20 ° C. to 40 ° C. Furthermore, an unreacted molecular chain does not become too long, and an excessive increase in tan δ can be suppressed. Moreover, when it is the prepolymer type polyol which contains a urethane group in a structure, it is preferable to exist in the range of 4000 <= Mn <= 30,000.

  In the present invention, among these polyol main raw materials, a mixture of polytetramethylene glycol (C) and polypropylene glycol (D) belonging to polyether polyol is particularly preferable. Since these materials have a glass transition temperature particularly on the low temperature side among the urethane resin raw materials, it is easy to adjust the glass transition temperature by the crosslinking reaction, and contribute to the control of the tan δ value in a wide temperature range. Further, since the tan δ of the resin raw material itself is relatively high, it contributes to an increase in tan δ. The number average molecular weight (Mn) of the polytetramethylene glycol (C) is preferably in the range of 500 ≦ Mn ≦ 2000. By controlling Mn to 500 or more, an excessive increase in crosslink density can be suppressed and the reactivity can be easily controlled, so that an excessive decrease in tan δ of the polyurethane resin particles (B) can be suppressed. Moreover, by being 2000 or less, while suppressing the excessive tan-delta rise, it becomes easy to have a glass transition temperature in the temperature range vicinity of -20 degreeC to 40 degreeC.

  Moreover, it is preferable that the number average molecular weight (Mn) of polypropylene glycol (D) exists in the range of 3000 <= Mn <= 7000 for the same reason as polytetramethylene glycol (C).

  The mixing ratio of different urethane main raw materials (polyols) varies depending on the structure and molecular weight of the raw materials and the number of mixed species, but is 0 for each of the total amount of polyhydroxy compounds in the urethane resin starting material. It is preferable that it exists in the range of 0.5-80 mass%.

  Further, the short-chain diol material that is a raw material of the urethane resin in the present invention is not particularly limited. For example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butane Diol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4-biscyclohexane, bisphenol A, hydroxypivalylhydroxypivalate, trimethylolethane, trimethylolpropane, 2,2,4- Examples include trimethyl-1,3-pentanediol, glycerin, hexanetriol, and mixtures thereof. In addition, the molecular weight of the short chain diol in the present invention is preferably 62 to 300.

  In the present invention, among these, 1,4-butanediol or 1,3-propanediol is particularly preferable. These materials are not only relatively low in cost, but also when used in combination with the high molecular weight polyol compound, the polyurethane network structure can be easily controlled, and tan δ can be easily controlled over a wide temperature range.

In addition, the mixing ratio of the short-chain diol material in the present invention varies in an optimum range depending on the structure and molecular weight of the raw material and the number of mixed species, but is independently 0.1% relative to the total amount of polyhydroxy compounds in the urethane resin starting material. It is preferable that it exists in the range of 1-5 mass%.
Although it does not specifically limit as an isocyanate compound, The following can be mentioned as an example. Diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 3,3′-dimethylbiphenyl-4,4′-diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, carbodiimide-modified MDI, xylylene diisocyanate, trimethylhexamethylene diisocyanate, toluene diisocyanate, Naphthylene diisocyanate, paraphenyl diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl polyisocyanate, copolymers thereof, block bodies and mixtures thereof. Among those exemplified above, the prepolymer type isocyanate having an ether group and an ester group in the modified part (soft segment part) is particularly preferable because of compatibility with the polyhydroxy compound and crosslinking reactivity, and easy control of tan δ. . Further, a mixture of prepolymer type isocyanates having different structures, NCO% and number average molecular weight (Mn) is preferable. By blending prepolymer type isocyanates having different structures, the distribution of the distance between crosslinks tends to be broad, and tan δ can be easily controlled in a wide temperature range.

  Further, the number average molecular weight of the isocyanate compound is preferably in the range of 1000 to 10,000, and more preferably in the range of 2000 to 8000. When Mn is 1000 or more, it is possible to easily achieve the tan δ value necessary for manifesting the effects of the present invention by suppressing an excessive increase in the crosslinking point density. Moreover, when it is 10,000 or less, it is possible to easily achieve the tan δ value necessary for the effect expression of the present invention. Furthermore, excessive tackiness on the surface of the polyurethane resin particles (B) can be suppressed, and initial toner adhesion can be suppressed.

  The isocyanate compound in the polyurethane resin particles (B) is preferably blended with respect to the polyhydroxy compound so that the isocyanate index is in the range of 0.6 to 1.0. Particularly preferred is a range of 0.7 to 0.9. By blending in the above range, it is possible to easily achieve the tan δ necessary for the present invention. By being 0.6 or more, an excessive increase in tack on the surface of the polyurethane resin particles (B) can be suppressed, and occurrence of initial toner fixation can be suppressed. Moreover, since it is 1.0 or less, the excessive fall of tan-delta of a polyurethane resin particle (B) can be suppressed, and mechanical energy can fully be dissipated, Therefore Banding generation | occurrence | production can be suppressed.

  Further, the method for synthesizing / preparing the polyurethane resin particles (B) in the present invention is not particularly limited, but it is synthesized by a conventionally known polymerization method such as emulsion polymerization, suspension polymerization, precipitation polymerization, or dispersion polymerization. It is possible. Furthermore, after forming a polyurethane resin molded body from the above-mentioned polyurethane resin raw material, it can be prepared by freeze pulverization with a fine pulverizer using a hammer mill or an air jet method. Further, the number average particle diameter can be appropriately adjusted by classifying the obtained finely pulverized product. This classification process can be performed simultaneously with the pulverization process. Furthermore, as a method of external addition of inorganic fine particles, conventional external mixing using a conventional mixing apparatus such as a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, and a Nauta mixer. it can. In addition, inorganic fine particles can be added during the synthesis.

  In addition, since the polyurethane resin (A) in the present invention is required to have a function as a matrix portion, it has high durability due to toner releasability, abrasion resistance, and stress relaxation with a contact member due to excellent compression set. From the viewpoint of expression, high elasticity is preferable.

  Therefore, tan δ (A) of the polyurethane resin (A) in the present invention measured within a frequency range of 10 Hz and a temperature range of −20 ° C. to 40 ° C. is preferably 0.10 or more and 0.40 or less. When tan δ (A) is 0.10 or more, mechanical energy can be sufficiently dissipated and banding can be suppressed. Moreover, by being 0.40 or less, an excessive increase in surface tackiness can be suppressed, and initial toner adhesion can be suppressed. Furthermore, toner fusion onto the surface layer of the developing roller when an image is repeatedly output under low temperature and low humidity can be suppressed. In addition, since tan δ of rubber or resin material shows a characteristic that peaks at the glass transition temperature, the polyurethane resin (A) in the present invention is near the temperature range of −20 ° C. to 40 ° C. from the above tan δ value range. Further, it has no glass transition temperature. By suppressing the transition of the glass / rubber state or the mixture of both states within the same temperature range, the environmental stability of the viscoelastic properties of the polyurethane resin (A) is improved, especially from low temperature and low humidity to high temperature and high humidity. Contributes to improved anti-banding performance in the environment.

  Further, the dynamic storage elastic modulus (E ′) of the polyurethane resin (A) measured within a frequency range of 10 Hz and −20 ° C. to 40 ° C. in the present invention is preferably 0.5 MPa or more and 500 MPa or less. . Particularly preferably, it is 5 MPa or more and 30 MPa or less. By being 0.5 MPa or more, initial toner fixation due to an excessive increase in tackiness of the outermost surface layer can be suppressed. Furthermore, banding due to a stick-slip phenomenon at the time of rubbing with the contact member can be suppressed. Further, when the pressure is 500 MPa or less, toner fusion on the surface layer of the developing roller when an image is repeatedly output at low temperature and low humidity can be suppressed.

  As the main raw material of the polyurethane resin (A), there can be mentioned those obtained by reacting a polyhydroxy compound and an isocyanate compound in the same manner as the polyurethane resin particles (B).

  Moreover, in the polyhydroxy compound which is the main raw material of the polyurethane resin (A) in the present invention, the optimum Mn differs depending on the type of isocyanate used as the curing agent, Mn, and whether or not urethane prepolymerization is possible. If it is a polyhydroxy compound which does not contain a urethane group in the structure, it is preferable that it is in the range of 1000 ≦ Mn ≦ 6000. When Mn is 1000 or more, an excessive increase in hardness of the polyurethane resin (A) can be suppressed, and toner fusion on the surface layer of the developing roller when an image is repeatedly output under low temperature and low humidity can be suppressed. . On the other hand, when Mn is 6000 or less, an increase in surface tackiness can be suppressed and initial toner adhesion can be prevented. Furthermore, an increase in tan δ due to an increase in unreacted hydroxy compound can be suppressed. Moreover, when it is the prepolymer type polyhydroxy compound which contains a urethane group in a structure, it is preferable to exist in the range of 3000 <= Mn <= 12000.

  The polyurethane resin (A) may contain carbon black for imparting conductivity and controlling mechanical properties. The content of carbon black in the polyurethane resin (A) is 5 with respect to 100 parts by mass of the resin component of the polyurethane resin (A) from the viewpoint of imparting a proper range of conductivity to the developing roller and controlling the mechanical properties. It is preferable that it is not less than 60 parts by mass. When the content of carbon black in the polyurethane resin (A) is 5 parts by mass or more, not only moderate conductivity can be obtained, but also compression set can be suppressed. On the other hand, by being 60 parts by mass or less, not only dispersion uniformity with respect to the resin component can be obtained, but also the hardness of the polyurethane resin (A) can be increased and tan δ can be suppressed, and a high-quality image can be obtained. To preferred.

  The average primary particle size of the carbon black is preferably 15 to 50 nm in consideration of maintaining the strength of the polyurethane resin (A) and exhibiting appropriate conductivity. The DBP absorption amount of carbon black is preferably 50 to 300 ml / 100 g for the same reason. As such carbon black, what was manufactured by methods, such as a channel method and a furnace method, can be used conveniently. Furthermore, you may mix | blend 2 or more types of carbon black according to a required physical property.

  The polyurethane resin (A) may contain fine particles in addition to the polyurethane resin particles (B) in order to impart an appropriate surface roughness to the surface of the developing roller. When the polyurethane resin (A) contains fine particles, the surface roughness of the surface of the developing roller can be controlled, and at the same time, surface wear can be suppressed even when image output is performed over a long period of time. . The fine particles preferably have a number average particle diameter of 2 to 40 μm. Further, the number average particle diameter of the fine particles can be measured by taking out from the outermost surface layer using an apparatus such as a manipulator like the polyurethane resin particles (B).

  As content of microparticles | fine-particles, it is preferable that it is 1-100 mass parts with respect to 100 mass parts of resins of a polyurethane resin (A).

  Examples of the material of the fine particles include polyester resin, polyether resin, acrylic resin, and polycarbonate resin. These fine particles can be produced by the same method as the polyurethane resin particles (B). Further, similarly to the polyurethane resin (B), inorganic fine particles may be externally added.

  In the polyurethane resin (A), the isocyanate compound is particularly preferably blended with respect to the polyhydroxy compound so that the isocyanate index is in the range of 1.0 to 1.5. By mix | blending in the said range, the raise of the excessive tan-delta and surface hardness by an unreacted polyhydroxy compound can be suppressed.

  The urethane resin (A) and the urethane resin particles (B) can specify the urethane species by analysis such as pyrolysis GC / MS, NMR, IR, and elemental analysis.

  As a method of forming the outermost surface layer, a composition containing the uncured binder polyurethane resin and the resin layer material of other components (referred to as an uncured composition) is prepared and used on the resin layer. The method of forming a coating film and hardening can be mentioned. The uncured composition is preferably prepared using a dispersion apparatus using beads such as a sand mill, a paint shaker, a dyno mill, and a pearl mill using methyl ethyl ketone, toluene, or alcohol as a solvent.

  A coating method such as spraying, dip coating, or roll coating can be used for forming the coating film. After the coating film is formed on the elastic layer, it is dried to remove the solvent and cure by heating. The method can be used. Curing and drying may be either heating or electron beam irradiation. Furthermore, you may coat | cover the outermost surface layer previously shape | molded by the tube shape on the roller in which the resin layer was formed.

  When dip coating is used for the coating film formation, it is preferable to use a coating apparatus having a paint circulation mechanism shown in the schematic configuration diagram of FIG.

  The dipping tank 5 is provided in the coating apparatus shown in FIG. The dipping bath has a cylindrical shape with an inner diameter slightly larger than the outer diameter of the roller 6 on which the resin layer 3 is formed and a depth longer than the axial length of the roller 6, and is set with the axial direction vertical. The An annular liquid receiving portion 7 is provided on the outer periphery of the upper end portion, and the liquid receiving portion is connected to the stirring tank 8 by a pipe 9 connected to the bottom surface thereof. On the other hand, the bottom of the immersion tank 5 is connected to a pump 11 that circulates the outermost surface layer forming paint 10 through a pipe 12, and is further connected to the stirring tank 8 by a pipe 12 that connects the pump 11 and the stirring tank 8. . The stirring tank 8 is provided with a stirring blade 14 for stirring the outermost surface layer-forming coating material 10 accommodated therein.

  This coating apparatus is provided with an elevating device 15 that raises and lowers the elevating plate 16 in the axial direction of the immersing tank in the upper part of the immersing tank, and the roller 6 suspended on the elevating plate 16 can enter and retract into the immersing tank. ing.

  In order to form the outermost surface layer on the resin layer using such a coating apparatus, the pump 11 is driven and the outermost surface layer forming coating material 10 stored in the stirring tank 8 is immersed through the pipes 12 and 13. Supply to tank 5. The elevating device 15 is driven to lower the elevating plate 16, and the roller 6 enters the immersion tank 5 filled with the outermost surface layer forming coating material 10. The outermost surface layer-forming paint 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 dipping tank at a predetermined speed to form a coating film on the resin layer. During this time, the stirring blade 14 is rotated in the stirring tank to stir the coating solution to suppress sedimentation of the contents and maintain the uniformity of the coating solution.

  The roller on which the coating film is formed is removed from the lifting plate 16, the coating film is dried and cured, and the outermost surface layer is formed.

  The resin layer 3 provided around the conductive shaft core 2 is a molded body using rubber or resin as a raw material main component. The resin layer 3 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.

  The raw material of the resin layer in the present invention is not particularly limited, but among these materials, urethane rubber or silicone rubber is used because it exhibits weather resistance, chemical inertness and excellent compression set properties. Is preferred.

  Furthermore, in the developing roller of the present invention, components such as a conductive agent and a non-conductive filler necessary for the function required for the resin layer itself, and various additions used when forming rubber and a resin molded body are used. Agent components such as a crosslinking agent, a catalyst, and a dispersion accelerator can be appropriately blended with the main rubber material.

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.
The following are mentioned as a conductive agent by an electronic conductive mechanism. 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 (trade name), PAN-based carbon black , Carbon conductive agents such as pitch-based carbon black and carbon nanotubes.
Moreover, the following are mentioned as an electrical conductivity imparting agent by an ionic conduction 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; aliphatic sulfonates, alkyl sulfates, alkyl phosphates Anionic surfactant; amphoteric surfactant such as betaine. These conductive agents can be used alone or in admixture of two or more.

  Among these, a carbon black-based conductive agent is preferable because it can be obtained relatively inexpensively and easily, and good conductivity can be imparted irrespective of the types of the main rubber and resin material. As means for dispersing the fine powdered conductive agent in the main rubber and resin material, the following means conventionally used may be appropriately used according to the main rubber and resin material. For example, means such as a roll kneader and a Banbury mixer can be used.

  For example, in order to produce a rubber molded body from silicone rubber, a liquid silicone rubber is used as a main agent, polyorganohydrogensiloxane is used as a crosslinking component, and a platinum catalyst is used to crosslink rubber components.

  The thickness of the resin layer is preferably 0.5 mm or more, more preferably 1 in order to ensure contact with the photoconductor to ensure a nip width and to satisfy a suitable setting property. 0.0 mm or more. Further, there is no upper limit on the thickness of the resin layer as long as the outer diameter accuracy of the developing roller to be manufactured is not impaired. However, if the thickness of the resin layer is excessively increased, leaving the developing roller 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 resin layer is suitably 6.0 mm or less, and more preferably 5.0 mm or less.

  Further, after the molding of the resin layer, 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 resin layer, and interlayer adhesion with the outermost surface layer can be improved.

  In the present invention, the resin layer can be molded by a conventionally known molding method such as extrusion molding, compression molding, or injection molding, 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.

  Furthermore, when the resin layer has two or more layers, the thickness of the outermost surface layer in the present invention is preferably 2 μm or more and 100 μm or less. By being 2 μm or more, an increase in surface tackiness due to excessive surface exposure of the resin particles (B) can be suppressed, and occurrence of initial toner fixation can be prevented. Further, when the thickness is 100 μm or less, it is possible to suppress an excessive increase in hardness, and it is possible to suppress image defects caused by toner deterioration due to repeated image output.

  In addition, the film thickness of the formed outermost layer is a digital microscope (VH-2450: Keyence Corporation), and the longitudinal direction of the developing roller is equidistant from the end portion at three locations, and is evenly spaced in the circumferential direction. A total of nine places are measured, and an arithmetic average value of the obtained values. Further, when the measurement sample contains fine particles as in the present invention, the measured value of the matrix portion forming a layer having a continuous surface is defined as the film thickness of the outermost surface layer in the present invention.

  The developing roller according to the present invention preferably has an Asker C hardness of 40 degrees or more and 80 degrees or less in order to reduce damage to a member such as a photosensitive member, a toner regulating member, and a toner. . Particularly preferably, the Asker C hardness is preferably 50 degrees to 70 degrees or less. When the Asker C hardness is within the above range, the influence of relative speed unevenness with various members that come into contact with the developing roller is mitigated, and banding can be effectively suppressed.

  The “Asker C hardness” is a hardness measured using an Asker-C hardness type spring type rubber hardness meter (manufactured by Kobunshi Keiki Co., Ltd.) in accordance with the Japan Rubber Association standard SRIS101. The measured value was measured 30 seconds after the hardness meter was brought into contact with a developing roller that was left in a humid environment (temperature 23 ° C., humidity 50% RH) for 12 hours or more with a force of 10 N. The sample for measuring Asker C hardness is obtained by cutting out and overlapping the resin layer and the outermost surface layer, and the thickness may be at least 5 mm.

  Further, the present invention is the process cartridge shown in FIG. 3 which has at least the developing roller 1, the toner regulating member 21, and the toner container 20, and is detachable from the electrophotographic image forming apparatus equipped with the developing roller. Further, according to the present invention, a thin layer of toner is formed on the surface of the developing roller, the toner is supplied to the surface of the photosensitive member by bringing the developing roller into contact with the photosensitive member, and thereby an electron that forms a visible image on the photosensitive member. A photographic image forming apparatus. The electrophotographic process cartridge 17 can be an all-in-one process cartridge together with the photosensitive member 18, the cleaning blade 26, the waste toner container 25, and the charging member 24, as in the electrophotographic process cartridge shown in FIG. 3.

  FIG. 4 is a cross-sectional view showing a schematic configuration of an electrophotographic image forming apparatus using an electrophotographic process cartridge having the developing roller of the present invention. The electrophotographic image forming apparatus shown in FIG. 4 includes a developing device 22 including a developing roller 1, a toner supply roller 19, a toner container 20, and a toner regulating member 21 disposed in contact with the photoconductor 18, a photoconductor 18, and a cleaning device. An electrophotographic process cartridge 17 comprising a blade 26, a waste toner container 25 and a charging member 24 is detachably mounted. Further, the photoconductor 18, the cleaning blade 26, the waste toner container 25, and the charging member 24 may be provided in the electrophotographic image forming apparatus. The photosensitive member 18 rotates in the direction of the arrow, is uniformly charged by a charging member 24 for charging the photosensitive member 18, and the surface thereof is exposed by laser light 23 which is an exposure means for writing an electrostatic latent image on the photosensitive member 18. An electrostatic latent image is formed. 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 drive 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 photoconductor 18 without being transferred is scraped off by a cleaning blade 26 which is a cleaning member for cleaning the surface of the photoconductor and stored in a waste toner container 25. The cleaned photoreceptor 18 repeats the above operation.

  The developing device 22 includes a developing container containing toner 20a as a one-component developer, and a developing roller as a developer carrying member located in an opening extending in the longitudinal direction in the developing container and disposed opposite to the photosensitive member 18. 1 and the electrostatic latent image on the photosensitive member 18 is developed and visualized.

  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. In addition, by applying a voltage higher than the voltage applied to the developing roller 1 to the toner regulating member 21, it is possible to control the toner layer on the developing roller. It is preferable to use a thin plate of phosphor bronze. A voltage is applied to the developing roller 1 and the toner regulating member 21 from the bias power supply 30, but the voltage applied to the developing blade 21 is 100 V to 300 V larger in absolute value than the voltage applied to the developing roller 1. It is preferable to use a voltage.

  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 toner regulating member 21 by the rotation of the developing roller 1. Here, the toner on the developing roller is uniformly coated on the developing roller by the bias applied to the toner regulating member 21. The developing roller 1 is in contact with the photosensitive member 18 while rotating, and a toner image is formed by developing the electrostatic latent image formed on the photosensitive member 18 with toner coated on the developing roller 1.

  As a 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 for supplying the toner 20a to the developing roller 1 and for the undeveloped toner. It is preferable from the point of peeling off. In the following examples, 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 developing roller 1 is preferably 1 to 8 mm, and the developing roller 1 is preferably given a relative speed at the contact portion.

  Hereinafter, the developing roller and the like according to the present invention will be described in detail with reference to examples.

First, the polyurethane resin particle (B) matrix in Examples and Comparative Examples of the present invention was prepared using the following starting materials.
[Polyurethane resin particles (B) starting material for base material]
・ Polytetramethylene glycol (C)
Product name: PTG500SN, number average molecular weight: 500, product name manufactured by Hodogaya Chemical Co., Ltd. Product name: PTG1000SN, number average molecular weight: 1000, product name manufactured by Hodogaya Chemical Co., Ltd., product name: Terratan 2000, number average molecular weight: 2000, polypropylene glycol manufactured by Deyupon (D )
Product name: Exenol 5030, number average molecular weight: 5100, Asahi Glass Co., Ltd. product name: Exenol 230, number average molecular weight: 3000, Asahi Glass Co., Ltd. product name: Exenol 851, number average molecular weight: 6700, Asahi Glass Co., Ltd. short chain Diol (F)
Product name: 1,4-butanediol, Sankyo Chemical Co., Ltd. product name: 1,3-propanediol, Sankyo Chemical Co., Ltd., isocyanate compound Product name: Coronate 4192, Nippon Polyurethane Industry Co., Ltd. Coronate 2515, manufactured by Nippon Polyurethane Industry Co., Ltd. Further, a method for producing polyurethane resin particles (B) matrix (1) will be specifically exemplified and described, but the present invention is not limited to these.

[Preparation of polyurethane resin particles (B) matrix (1)]
The polyurethane resin particle (B) matrix (1) in the present invention was prepared by dissolving and mixing the starting materials shown in Table 1 in a MEK solvent and then heating at 140 ° C. for 4 hours to advance the crosslinking reaction.
Polytetramethylene glycol (C) (trade name: PTG500SN, number average molecular weight: 500, manufactured by Hodogaya Chemical Co., Ltd.) 30 parts by mass Polypropylene glycol (D) (trade name: Exenol 5030, number average molecular weight: 5100, Asahi Glass Co., Ltd. 68 parts by mass Short chain diol (trade name: 1,4-butanediol, Sankyo Chemical Co., Ltd.) 2 parts by mass Isocyanate compound 1 (trade name: Coronate 4192, manufactured by Nippon Polyurethane Industry Co., Ltd.) 148 .3 parts by mass ・ Isocyanate compound 2 (trade name: Coronate 2515, manufactured by Nippon Polyurethane Industry Co., Ltd.) 68.2 parts by mass In the temperature range of −20 ° C. to 40 ° C. of the produced polyurethane resin particles (B) matrix (1) The minimum value of tan δ was 0.40 (40 ° C.).

[Production of Polyurethane Resin Particles (B) Bases (2) to (9)]
The polyurethane resin particles (B) bases (2) to (9) in the present invention were prepared in the same manner as the polyurethane resin particles (B) base (1) using the starting materials described in Tables 1 and 2.

Next, the production of polyurethane resin particles (B) in Examples and Comparative Examples of the present invention was performed using the above-mentioned polyurethane resin particle (B) matrix and the following inorganic fine particles.
[Inorganic fine particles used to produce polyurethane resin particles (B)]
Silica (trade name: Leolosil MT-10, titanium oxide manufactured by Tokuyama Co., Ltd. (trade name: JA-1, manufactured by Teika)
Alumina (trade name: AluC805, manufactured by Nippon Aerosil Co., Ltd.)
In addition, although the preparation method of a polyurethane resin particle (B) 1 is illustrated and demonstrated concretely, this invention is not limited to these.

[Preparation of polyurethane resin particles (B) 1]
The obtained polyurethane resin particles (B) matrix (1) was immersed in liquid nitrogen for 48 hours and completely frozen, and then crushed with a hammer to form a coarse powder. Thereafter, freeze pulverization and classification were simultaneously performed using a collision type supersonic jet pulverizer (trade name: CPY + USF-TYPE, manufactured by Nippon Pneumatic Industry Co., Ltd.). Thereafter, 3 parts by mass of silica (trade name: Leolosil MT-10, manufactured by Tokuyama Co., Ltd.) is treated with a Henschel mixer (manufactured by Mitsui Miike Co., Ltd.) at 3000 rpm for 15 minutes, and externally treated. Polyurethane resin particles (B) 1 having an average particle diameter of 10 μm were obtained.

[Production of Polyurethane Resin Particles (B) Bases (2) to (36)]
The polyurethane resin particles (B) (2) to (36) in the present invention were prepared in the same manner as the polyurethane resin particles (B) (1) using the above-mentioned polyurethane resin particles (B) matrix and inorganic fine particles. . Each number average particle size was controlled by performing a classification treatment. Table 3 shows the base number, the number average particle diameter, and the inorganic fine particle species of the polyurethane resin particles (B) used for the production of each polyurethane resin particle (B).

  Subsequently, the production method of the resin layer roller in the examples and comparative examples of the present invention will be specifically illustrated and described below, but the present invention is not limited thereto.

[Production of Resin Layer Roller 1]
In the resin layer roller 1 of the present invention, liquid silicone rubber base materials A and B each having a vinyl group and a SiH group as reaction groups are mixed at a mass ratio of 1: 1 to thermally cure unvulcanized silicone rubber. It was produced.
(Liquid silicone rubber base material A having vinyl group)
-100 parts by mass of dimethylpolysiloxane having vinyl groups at both ends and a weight average molecular weight (Mw) of 85000-Carbon black (trade name: Ketjen Black EC-DJ600, manufactured by Ketjen Black International) 2 parts by mass-Carbon Black (trade name: Printex L, manufactured by Evonik Degussa Japan) 3 parts by mass (liquid silicone rubber base material B having SiH group and vinyl group)
-100 parts by mass of dimethylpolysiloxane having vinyl groups at both ends and a weight average molecular weight (Mw) of 85000-Carbon black (trade name: Ketjen Black EC-DJ600, manufactured by Ketjen Black International) 2 parts by mass-Carbon Black (trade name: Printex L, manufactured by Evonik Degussa Japan) 3 parts by mass-Curing catalyst (2 mass% of isopropanol solution of chloroplatinic acid mixed with 10 ppm with respect to dimethylpolysiloxane) 0.5 parts by mass 3 parts by mass of methyl hydrogen polysiloxane (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, a primer (trade name: DY35-051, manufactured by Toray Dow Corning Co., Ltd.) is applied to a core bar made of SUS304 with a diameter of 8 mm so as to have 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 resin was further heated at 180 ° C. for 1 hour to complete the curing reaction, and a resin layer was provided around the shaft core body. The diameter of the produced resin layer roller 1 was 12 mm.

[Production of Resin Layer Roller 2]
The resin layer roller 3 having a diameter of 12 mm is used in the same manner as the resin layer roller 1 except that the following uncured urethane rubber material is used as a material for the resin layer roller 2 in the present invention and is thermally cured at 80 ° C. for 1 hour. Produced.
・ Polyester polyol (trade name: N-4748, manufactured by Nippon Polyurethane Industry Co., Ltd.)
100 parts by mass / aliphatic modified isocyanate (trade name: HC-210, manufactured by Nippon Polyurethane Industry Co., Ltd.) 24 parts by mass / 25 parts by mass of polyurethane resin particles (B) (based on 100 parts by mass of polyurethane resin (A) raw material 20 parts by mass)
・ Reaction catalyst (trade name: dibutyltin dilaurate, manufactured by Kyodo Yakuhin Co., Ltd.)
0.1 parts by mass carbon black (trade name: Printex L, manufactured by Evonik Degussa Japan)
8 parts by mass

[Production of Resin Layer Roller 3]
Resin layer roller 3 having a diameter of 12 mm was prepared in the same manner as resin layer roller 2 except that polyurethane resin particle (B) 6 was used instead of polyurethane resin particle (B) 5.

[Production of resin layer roller 4]
Resin layer roller 4 having a diameter of 12 mm was prepared in the same manner as resin layer roller 2 except that polyurethane resin particle (B) 7 was used instead of polyurethane resin particle (B) 5.

[Production of resin layer roller 5]
Resin layer roller 5 having a diameter of 12 mm was prepared in the same manner as resin layer roller 2 except that polyurethane resin particle (B) 9 was used instead of polyurethane resin particle (B) 5.
Then, the coating liquid for outermost surface layer formation containing the polyurethane resin (A) in the Example and comparative example of this invention below was prepared using the starting material which consists of a polyol and an isocyanate compound shown below.

[Starting material of coating liquid for outermost surface layer formation]
(Polyol)
Ester diol (trade names: P-3010, P-4010, P-5010, P-3050, manufactured by Kuraray Co., Ltd.)
・ Polycaprolactone diol (trade name: L-220AL, manufactured by Daicel Chemical Industries, Ltd.)
(Isocyanate compound)
Ester-modified isocyanate (trade name: Coronate 4047, manufactured by Nippon Polyurethane Industry Co., Ltd.)
Ether-modified isocyanate (trade name: Coronate 4190, manufactured by Nippon Polyurethane Industry Co., Ltd.)
In addition, although the coating material preparation method is illustrated and demonstrated concretely below, this invention is not limited to these.

“Preparation of coating liquid for outermost surface layer formation (1)”
-Ester diol (trade name: P-5010, manufactured by Kuraray Co., Ltd.) 100 parts by mass-Ester-modified isocyanate (trade name: Coronate 4047, manufactured by Nippon Polyurethane Industry Co., Ltd.) 57.8 parts by mass of the coating liquid for forming the outermost surface layer As a material, the above components were mixed to obtain a polyurethane resin component (A). Subsequently, 20 parts by mass of carbon black (trade name: MA-100, manufactured by Mitsubishi Chemical Corporation) and methyl ethyl ketone were added to 100 parts by mass of the solid content of the resin component, and the mixture was mixed and stirred with a motor for 1 hour. 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 above mixed solution was uniformly dispersed with a horizontal dispersion NVM-03 (trade name, manufactured by Imex Corporation) 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 of SΦ = 1.5 mm (trade name: DMB503B, manufactured by Hotters Ballotinis) were used. Next, 20 parts by mass of polyurethane resin particles (B) 1 was added to 100 parts by mass of the solid content of the resin component, and further dispersed for 15 minutes. Next, this solution was diluted with MEK so as to have a solid content of 27% by mass, and this solution was filtered through a 200-mesh net to obtain an outermost surface layer forming coating liquid (1).

“Preparation of coating liquids (2) to (43) for forming the outermost surface layer”
The outermost surface layer-forming coating liquids (2) to (43) in the present invention are the same as the outermost surface layer-forming coating liquid (1) except that the above starting materials and polyurethane resin particles (B) were used. It was prepared with. Table 4 shows the trade names, parts by mass, polyurethane resin particle (B) numbers, and parts by mass of the starting materials used in the preparation of each outermost surface layer forming coating liquid. In addition, a mass part of a polyurethane resin particle (B) is a value with respect to 100 mass parts of solid content of the mixed resin component of the polyol and isocyanate compound of each coating liquid here.

  Subsequently, measurement of tan δ using the dynamic viscoelasticity device in Examples and Comparative Examples of the present invention and a method of measuring the number average molecular weight (Mn) of the urethane main material will be described below.

[Measurement of tan δ / Measurement method of main urethane material]
(Tan δ measurement by dynamic viscoelasticity measurement)
In the present invention, tan δ was measured using a dynamic viscoelasticity measuring device (trade name: EPLEXOR-500N, manufactured by GABO) under the following conditions. Moreover, the measurement sample was prepared by separating the polyurethane resin (A) and the polyurethane resin particles (B) from the outermost surface layer of the developing roller using a manipulator, and then compression-molding each. Tables 5 to 10 show the measurement results of the developing rollers produced in each Example and Comparative Example.
〔Measurement condition〕
・ Measurement mode: Compression test mode ・ Measurement frequency: 10 Hz
Measurement temperature range: -60 ° C to 60 ° C
Temperature increase rate: 3 ° C / min
Transducer: 25N
Measurement sample shape: 2mm diameter x 1mm height

(Number average particle diameter measurement of urethane particles (B))
The number average particle diameter of the urethane resin particles (B) in the present invention is a precision particle size distribution measuring device by a pore electrical resistance method equipped with an aperture tube of 100 μm (trade name: Coulter Counter Multisizer 3, manufactured by Beckman Coulter, Inc.) It measured using. For setting of measurement conditions and analysis of measurement data, attached dedicated software (trade name, Beckman Coulter Multisizer 3 Version 3.51, manufactured by Beckman Coulter, Inc.) was used. The measurement was performed with 25,000 effective measurement channels. As an electrolytic aqueous solution used for measurement, ISOTON II (trade name, manufactured by Beckman Coulter, Inc.) was used.
(Method for measuring hydroxyl value and NCO% of urethane resin raw material)
In the present invention, the hydroxyl value of the polyhydroxy compound was measured according to JIS K-1557. Furthermore, the measurement of NCO% per isocyanate compound solid content in the present invention was performed as follows. The sample was dissolved in toluene, a dibutylamine 0.5 mol / L monochlorobenzene solution was added, and the mixture was reacted under heating under reflux conditions for 30 minutes, and then cooled to room temperature. Thereafter, methanol was added as a cosolvent, and the value obtained by back titrating excess amine with 0.5 mol / L hydrochloric acid was converted to solid content. As the numerical value, an average value measured at n = 3 was used.

(Measurement of Mn of urethane main raw material 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. Measurement was performed using a measurement sample prepared as a 0.1 mass% THF solution under the conditions of solvent tetrahydrofuran (THF), temperature 40 ° C., flow rate 0.6 ml / min, RI (refractive index) detector. It was. 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 ) Tables 5 to 10 show the measurement results of the developing rollers produced in each example and comparative example.

Example 1
First, the resin layer roller 1 was subjected to excimer UV treatment to perform surface treatment. While rotating at 30 rpm with the shaft core body of the resin layer roller 1 as the rotation axis, the processing is performed by irradiating ultraviolet rays having a wavelength of 172 nm with a capillary excimer lamp (manufactured by Harrison Toshiba Lighting) so that the integrated light quantity becomes 150 mJ / cm ^2. went. The distance between the resin layer surface and the excimer lamp at the time of irradiation was 2 mm. Then, the outermost surface layer was formed by applying the outermost surface layer-forming coating material 1 using the dipping coating method.

  When forming the outermost surface layer, 250 cc of the outermost surface layer-forming coating material (1) maintained at a liquid temperature of 23 ° C. is injected from the lower side of a cylinder having an inner diameter of 32 mm and a length of 300 mm, and overflows from the upper end of the cylinder. The discharged liquid was circulated again below the cylinder. The resin layer roller (1) is immersed in the cylinder at a penetration speed of 100 mm / s and stopped for 10 seconds, and then the resin layer roller (1) is pulled up under the conditions of an initial speed of 300 mm / s and a final speed of 200 mm / s. Allow to air dry for a minute. Next, the raw material of the outermost surface layer was cured by heat treatment at 140 ° C. for 2 hours, and the developing roller 1 of Example (1) was produced.

  Furthermore, when the polyurethane resin (A) and the polyurethane resin particles (B) were separated using a manipulator and each tan δ was measured using a dynamic viscoelastic device under the following conditions, the maximum value of tan δ (A) was obtained. = 0.05 (T = −20 ° C. to 40 ° C.), lowest value of tan δ (B) = 0.40 (T = 40 ° C.). Moreover, the minimum value of tan (B) -tan (A) in the temperature range of -20 ° C to 40 ° C was 0.35 (T = 40 ° C). Table 5 shows the evaluation of various characteristics of the developing roller 1 and the image evaluation results.

(Examples 2 to 40)
Evaluation of various characteristics and image evaluation of the developing rollers 2 to 40 in Examples 2 to 40 were performed in the same manner as the developing roller 1 of Example 1. The evaluation results of the developing rollers 2 to 40 are shown in Tables 5 to 10.

(Comparative Examples 1-7)
Evaluation of various characteristics and image evaluation of the developing rollers 41 to 47 in Comparative Examples 1 to 7 were performed in the same manner as the developing roller 1 of Example 1. Table 10 shows the evaluation results of the developing rollers 41 to 47.

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

[Image evaluation]
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 CP3505dn, manufactured by Hured Packard) is modified to 48 ppm. Further, the contact pressure and the approach amount of the developing roller to the toner amount regulating member (developing blade) were adjusted so that the toner carrying amount on the developing roller was 0.40 mg / cm ² .

[Image evaluation of initial toner adhesion in high temperature hard and humid environment]
The developing roller was incorporated into an electrophotographic process cartridge Q6470A (trade name, manufactured by Hured Packard, color: black), 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, the developing roller was remounted on a newly prepared electrophotographic process cartridge, and further left in an environment of a temperature of 30 ° C. and a humidity of 85% RH for 24 hours. Then, in the same environment, the electrophotographic process cartridge was installed in a modified Hued Packard printer (trade name: HP Color LaserJet CP3505dn), and 10 solid white images were output. This solid white image was evaluated for image defects due to initial toner fixation during standing according to the following evaluation criteria. Tables 5 to 10 show the evaluation results of the developing rollers produced in each Example and Comparative Example.
A: No image defect such as fogging due to initial toner fixation is observed in the solid white image. B: An image defect such as fog caused by initial toner fixation is confirmed in the solid white image, but disappears when the image is output within the initial three sheets.
C: An image defect such as fogging caused by initial toner fixation is confirmed in the solid white image, but disappears when the image is output from the initial 4 to 10 images.
D: An image defect such as a fog caused by the initial toner fixation is confirmed in the solid white image, and does not disappear within 10 sheets of the initial solid white image output.

[Evaluation of toner fusion in low temperature and low humidity environment]
A new developing roller was incorporated into a new electrophotographic process cartridge Q6470A (trade name, manufactured by Hured Packard, color: black), and this electrophotographic process cartridge was left in an environment of temperature 5 ° C. and humidity 10% RH for 48 hours. . In the same environment, the electrophotographic process cartridge was installed in a modified printer manufactured by Hured Packard (trade name: HP Color LaserJet CP3505dn), and continuous image output was performed at a printing rate of 1%. The evaluation of fog in the durability test was performed according to the following evaluation criteria by counting the number of output sheets in which fog exceeding 3% was observed in the solid white portion. Also, using a reflection densitometer made by Macbeth for every 5000 outputs, the reflectance of the non-printed portion (reference) and the solid white portion of the print range is measured, and the amount of decrease in reflectance (%) relative to the reference is expressed as “fogging”. " Further, when the number of continuous prints exceeded 10,000, the developing roller was incorporated into a new electrophotographic process cartridge, and toner fusion was continuously evaluated. Tables 5 to 9 show the evaluation results of the developing rollers produced in each Example and Comparative Example.
A: The fog of 3% or more is not confirmed even when printing 15000 sheets in continuous printing.
B: Fog of 3% or more was confirmed on 10000 or more and less than 15000 continuous printing.
C: Fog of 3% or more was confirmed on continuous printing 5000 sheets or more and less than 10,000 sheets.
D: Fog of 3% or more was confirmed on less than 5000 continuous prints.

[Evaluation of banding]
After evaluating the image of initial toner adhesion in a high temperature and high humidity environment, the electrophotographic process cartridge was installed in a modified Hured Packard printer (trade name: HP Color LaserJet CP3505dn) in that environment, and continuous image output was performed at a printing rate of 1%. Went. A solid image and a halftone image were output every 5000 sheets of output, and streaks generated in the driving gear cycle of the developing roller in a direction perpendicular to the image printing direction were defined as banding images, and banding was evaluated under the following conditions. Further, when the number of continuous prints exceeded 10,000, the developing roller was incorporated into a new electrophotographic process cartridge, and evaluation was continued. Note that the evaluation of banding in a low temperature and low humidity environment was performed simultaneously with the toner fusion evaluation described above. Tables 5 to 10 show the evaluation results of the developing rollers produced in each example and comparative example.
A: A banding image was not recognized in both environments even after printing 15000 sheets continuously.
B: After printing 15000 sheets continuously, a slight banding image is recognized in both environments or either environment, but there is no practical problem.
C: Banding images were recognized in both or one of the environments within a continuous printing of 5000 to 15000 sheets.
D: Banding images were recognized in both environments or in either environment within the continuous printing of 5000 sheets.

DESCRIPTION OF SYMBOLS 1 Developing roller 2 Conductive shaft core 3 Resin layer 4 Outermost surface layer

Claims (7)

A developing roller having a shaft core and at least one resin layer provided around the shaft core,
The outermost surface layer of the developing roller contains a polyurethane resin (A) as a binder resin and polyurethane resin particles (B) dispersed in the polyurethane resin (A),
The loss tangent (tan δ) of the polyurethane resin (A) and the polyurethane resin particles (B) measured at a measurement temperature T (T = −20 ° C. to 40 ° C.) and a frequency of 10 Hz are respectively tan δ (A) and tan δ. A developing roller that satisfies the following formulas (1) and (2) when defined as (B):
0.40 ≦ tan δ (B) ≦ 1.10 (1)
0.30 ≦ tan δ (B) −tan δ (A) ≦ 0.70 Equation (2)   The developing roller according to claim 1, wherein the polyurethane resin particles (B) have a number average particle diameter of 5 μm or more and 50 μm or less.   The developing roller according to claim 1 or 2, wherein the surface of the polyurethane resin particles (B) is coated with inorganic fine particles containing at least one element selected from silicon, titanium and aluminum.   4. The tan δ (A) measured at a measurement temperature of −20 ° C. to 40 ° C. and a frequency of 10 Hz of the polyurethane resin (A) is 0.10 or more and 0.40 or less. 4. The developing roller as described. The polyurethane resin particles (B) are obtained by reacting a mixture of the following polyhydroxy compounds (C), (D) and (E) with an isocyanate compound in an isocyanate index range of 0.6 to 1.0. The developing roller according to claim 1, wherein the developing roller is formed.
(C) Polytetramethylene glycol of 500 ≦ Mn ≦ 2000 (D) Polypropylene glycol of 3000 ≦ Mn ≦ 7000
(E) at least one short-chain diol selected from the group consisting of 1,4-butanediol and 1,3-propanediol   An electrophotographic process cartridge that is detachably attached to an electrophotographic image forming apparatus, the electrophotographic process cartridge including at least a developing roller, a toner regulating member, and a toner container, wherein the developing roller comprises: 5. An electrophotographic process cartridge, which is the developing roller according to any one of 4 above.   An electrophotographic image forming apparatus having a photosensitive member and a developing roller disposed in contact with the photosensitive member, wherein the developing roller is the developing roller according to any one of claims 1 to 4. An electrophotographic image forming apparatus.

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