JP2012037644A - Developing roller, developing device and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing roller which is excellent in interlayer adhesion between a silicone resin layer and a surface layer when storing under high temperature and high humidity for a long time and is capable of suppressing an image stripe caused by long term contact with a developing blade and toner adhesion when an image is output repeatedly under low temperature and low humidity.SOLUTION: A developing roller includes a surface layer on the outer periphery of a resin layer, the resin layer of a silicone resin, the surface layer containing a cured polyurethane resin having a Martens hardness MH ranging from 3.0 to 4.5 under measurement conditions of a temperature of -10°C, a load of 0.050 mN/10s, a loading time of 5.0 s and an indentation depth of t/4 when the film thickness is defined as t (4 μm≤t≤20 μm) and satisfies the following expression when the position at the depth 7t/8 from the surface is defined as Y: 2.0≤UrcY (atoms of the nitrogen element derived from the urethane group in Y measured by ESCA, %)≤4.0(%) ...Expression (1)

Description

  The present invention relates to a developing roller used in an electrophotographic apparatus, a developing apparatus using the same, and the like.

  In a developing roller having two or more layers such as a resin layer and a surface layer, adhesion between layers deteriorates due to long-term standing in a high-temperature and high-humidity environment, and delamination may occur. . Further, when the resin layer and the surface layer are of different material types, the interlayer affinity is poor, and thus delamination may occur easily.

  Further, it may be very difficult to achieve both image characteristics in a high temperature and high humidity (temperature 40 ° C./humidity 95% RH) environment and a low temperature and low humidity (temperature 10 ° C./humidity 10% RH). Particularly under high temperature and high humidity, the surface layer of the developing roller tends to be flexible, the amount of deformation of the contact portion due to long-term contact with the developing blade increases, and image defects such as image streaks due to roller deformation may occur. . On the other hand, in a low-temperature and low-humidity environment, the hardness of the developing roller surface layer increases, so the stress on the toner increases, and the toner adheres to the developing roller surface layer before the life of the process cartridge for the electrophotographic apparatus. In some cases, image defects such as fogging may occur.

  In recent years, the need for high-speed image output has also increased. Along with this, the friction between the toner supply roller or the developing blade and the developing roller increases, so that delamination easily occurs, and further improvement in adhesion between the developing roller resin layer and the surface layer is required.

As a method for solving the above problem, it is conceivable to provide an intermediate layer between the resin layer and the surface layer. A method of manufacturing a semiconductive roller has been proposed in which the SiO ₂ layer is uniformly formed on the surface of the semiconductive resin roller and then the surface resistance adjustment layer is formed to improve the adhesion between the resin layer and the surface layer. (Patent Document 1). In order to cope with the higher speed of image output, a patent specifying the raw material of ester urethane material and JIS-A hardness has been proposed (Patent Document 2).

JP 2006-337622 A JP-A-8-208087

  However, in the electrophotographic rubber rollers described in Patent Documents 1 and 2, the interlaminar adhesion sometimes deteriorates when left for a long time in a high temperature and high humidity environment.

  An object of the present invention is to provide a developing roller capable of forming a high-quality electrophotographic image over a long period of time. Another object of the present invention is to provide an electrophotographic apparatus and a process cartridge capable of stably forming a high-quality electrophotographic image.

  In view of the above-mentioned problems, the present inventors have developed an interlayer adhesion between a silicone resin layer and a urethane surface layer under high temperature and high humidity, image streaks due to long-term contact with a developing blade, and a surface on a developing roller surface layer under low temperature and low humidity. Attempts were made to improve image defects caused by toner fixation. As a result, by optimizing the nitrogen group concentration near the interface between the silicone resin layer and the urethane surface layer, the film thickness of the surface layer, and the mechanical properties, a developing roller, a developing device, and an image forming apparatus that can achieve the above object are provided. Found that can be obtained.

That is, according to the present invention, in a developing roller having a shaft core, a resin layer provided around the shaft core, and a surface layer provided on the outer periphery of the resin layer,
The resin layer includes a silicone resin, the surface layer includes a polyurethane resin,
The surface layer has a temperature of −10 ° C., a load of 0.050 mN / 10 s, a load time of 5.0 s, and an indentation depth from the surface of the surface layer of t / 4 (where t is the thickness of the surface layer). The Martens hardness HM in the range of 3.0 to 4.5, and the atomic percentage of the nitrogen element derived from the urethane group at a position 7t / 8 from the surface of the surface layer is 2%. A developing roller having a value of 0.0 or more and 4.0 or less is provided.

  In addition, according to the present invention, there is provided a process cartridge that is detachable from an electrophotographic apparatus and includes the developing roller. Furthermore, according to the present invention, there is provided an electrophotographic apparatus comprising the above developing roller and a photoreceptor.

  According to the present invention, it is possible to obtain a developing roller in which delamination between the silicone resin layer and the urethane surface layer hardly occurs even when stored for a long period of time under high temperature and high humidity. Further, according to the present invention, it is possible to obtain a process cartridge and an electrophotographic apparatus that can stably form a high-quality electrophotographic image under various environments.

It is sectional drawing of an example of the developing roller of this invention. It is a schematic diagram of the liquid circulation type dip coating apparatus used for surface layer formation. It is a schematic block diagram which shows an example of the process cartridge of this invention. 1 is a schematic configuration diagram illustrating an example of an electrophotographic apparatus of the present invention.

The developing roller of the present invention has a shaft core body, a resin layer around the shaft core body, and a surface layer on the outer periphery of the resin layer, and the following conditions must be satisfied.
(A) The resin layer is a silicone resin.
(B) The surface layer contains a cured polyurethane resin.
(C) When the film thickness of the surface layer is defined as t (4 μm ≦ t ≦ 20 μm), measurement of temperature −10 ° C., load 0.050 mN / 10 s, load time 5.0 s, indentation depth t / 4 Under the conditions, the Martens hardness HM is in the range of 3.0 to 4.5.
(D) When a position at a depth of 7t / 8 from the surface layer is defined as Y, the following formula (1) is satisfied.
2.0 ≦ UrcY (atomic% of nitrogen element derived from urethane group in Y measured by ESCA) ≦ 4.0 (%) Formula (1)

  In the present invention, a resin layer is provided around the shaft core body, and the resin layer is made of a silicone resin. Here, the silicone resin is not a name indicating a polymer having a single composition, but a general term for resin materials made mainly of polydiorganosiloxane (silicone polymer). If necessary, mechanical powder, electrical properties, etc., with appropriate addition of reinforcing fillers such as quartz powder, diatomaceous earth, dry silica, wet silica, various additives, conductive agents such as carbon black, and crosslinking agents. Can be controlled. Silicone resins exhibit particularly high weather resistance and chemical inertness compared to general natural rubber and synthetic rubber. Silicone resins also exhibit excellent compression set properties. Accordingly, the resin layer according to the present invention is made of a silicone resin in order to suppress changes in physical properties with time in various environments and to make it difficult to cause compression set in the resin layer by long-term contact with the developing blade or by the contact portion. Including.

  In addition, in order to supply the toner formed in a thin film by a developing blade that contacts the surface of the developing roller to a photosensitive member such as a photosensitive drum, a silicone resin layer is appropriately used so as to impart appropriate elasticity to the developing roller. It is preferable to have excellent elasticity. Furthermore, it is preferable that the compression set of the silicone resin layer is small in order to suppress the occurrence of deformation due to the pressing force received from the photoreceptor and the developing blade and to obtain a high-quality image over a long period of time. Furthermore, the mass content of the resin component in the silicone resin layer is preferably 70 parts by mass or more in order to improve adhesion to the surface layer described later. More preferably, it is 80 parts by mass or more. Further, it is preferable that the resin layer has a low hardness in order to reduce damage to the photoconductor, the developing blade, the toner, and the like that are in contact with the developing roller. The hardness is preferably 20 to 80 in terms of Asker C hardness. By setting the Asker C hardness of the resin layer to 20 or more, it is possible to more effectively suppress the occurrence of image streaks due to plastic deformation due to long-term pressure contact with other members. In addition, although the specific technical background will be described later, since it is not necessary to reduce the molecular weight of the silicone resin by setting the Asker C hardness of the resin layer to 80 or less, the interaction by the intermolecular force with the surface layer is eliminated. It is possible to improve more effectively and improve interlayer adhesion. Particularly preferred Asker C hardness is 50 or more and 70 or less.

  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 Japan Rubber Association standard SRIS101. In addition, the measured value 30 seconds after the hardness meter was brought into contact with the developing roller with a force of 10 N against a developing roller left for 12 hours or more in an environment of normal temperature and normal humidity (temperature 23 ° C., humidity 50% RH) did.

  In the present invention, the surface layer contains a polyurethane resin. Therefore, interlayer adhesion in the present invention means adhesion between a silicone resin and a polyurethane resin formed on the outer periphery thereof. As a result of diligent study, the inventors of the present invention have clarified that the interlayer adhesion strongly depends on the amount and form of chemical bonds at the time of surface layer formation. . In general, silicone resin and polyurethane resin have poor affinity due to the difference in chemical structure, and furthermore, it is difficult to form chemical bonds that contribute to interlayer adhesion such as covalent bonds, hydrogen bonds, and intermolecular interactions. It is known that the interlayer adhesion is poor. Therefore, conventionally, a wide range of techniques for increasing the amount of chemical bonds and improving interlayer adhesion by forming a surface layer after applying surface treatments such as excimer UV treatment, plasma treatment, corona treatment, and flame treatment to the resin layer. Has been used. However, the hydrogen bond and the intermolecular interaction formed by the above method are likely to cause bond dissociation due to the influence of moisture and heat. In particular, when it is stored for a long time in a high-temperature and high-humidity environment where there is a large amount of absolute water and the molecular motion of the resin is active, the amount of chemical bonds resulting from hydrogen bonding and intermolecular interactions decreases, resulting in poor interlayer adhesion. It has become clear. Therefore, in order to maintain interlayer adhesion in a high temperature and high humidity environment for a long period of time, the amount of covalent bond between the silicone resin layer and the urethane resin is increased, and the bond amount and strength of the hydrogen bond / intermolecular interaction itself are increased. Need to increase. In view of the above problems, the present inventors have intensively studied and found that it is necessary to use a cured polyurethane resin having a predetermined hardness for the surface layer in order to exhibit the effects of the present invention. I made it. This is because at the same time as the curing reaction of the surface layer occurs, the reactive groups are excited by the energy during curing, and the formation of chemical bonds such as covalent bonds at the interface between the silicone resin layer and the surface layer is likely to proceed simultaneously. it is conceivable that. Moreover, it is preferable that it is the hardened polyurethane resin also from a viewpoint of increasing the residual stress which arises from the thermal expansion coefficient difference of a resin layer and a surface layer at the time of hardening reaction, and a raise of adhesiveness. Furthermore, in order to express the effect of the present invention, it has excellent compression set as compared with the thermoplastic polyurethane resin and can suppress deformation due to the contact member. It is necessary to use it.

  Moreover, as a standard of the film thickness (t) of the surface layer in this invention, they are 4 micrometers or more and 20 micrometers or less.

  Further, the surface layer in the present invention has a Martens hardness HM of 3 under the measurement conditions of a temperature of −10 ° C., a load of 0.050 mN / 10 s, a load time of 5.0 s, and an indentation depth t / 4 μm from the surface of the surface layer. The range is from 0.0 to 4.5. A detailed measurement method will be described later. Here, the Martens hardness HM is a value obtained by applying a weight to the indenter continuously and directly reading the indentation depth under the weight. Martens hardness HM is a value indicating continuous hardness. Further, the Martens hardness HM in the present invention is a value measured by a Fisher ultra micro hardness test system called a picodenter. The picodenter is a measuring device capable of measuring with a displacement accuracy of nanometer (nm) order or less and a load accuracy of 100 nN or less. Therefore, even with a developing roller having a two-layer structure as in the present invention, the hardness of the surface layer is measured without being affected by the silicone resin layer as a base as much as possible, compared to a general measuring machine called a Fischer hardness meter. Is possible. When the Martens hardness HM is 3.0 or more, an increase in compression set can be suppressed. Further, when the Martens hardness HM is 4.5 or less, the stress applied to the toner can be reduced. On the other hand, if the Martens hardness HM is less than 3.0, image streaks due to long-term contact with the developing blade may deteriorate due to an increase in compression set. On the other hand, if the Martens hardness HM is greater than 4.5, the adverse effect of the image due to toner fixation when an image is repeatedly output may be deteriorated.

  Further, the surface layer according to the present invention has an atomic% (hereinafter also referred to as “UrcY”) of nitrogen element derived from a urethane group measured by ESCA at a depth of 7 t / 8 from the surface of the surface layer. 0.0 or more and 4.0 or less (2.0% or more and 4.0% or less).

  UrcY represents the atomic% of the nitrogen element derived from the urethane group in the vicinity of the silicone resin layer inside the surface layer. The atomic% of the nitrogen element derived from the urethane group in the vicinity of the silicone resin layer is an index indicating the amount of covalent bonds formed between the silicone resin and the surface layer. Furthermore, it means that the strength of hydrogen bonding and intermolecular interaction is strong. This is because the hydrogen bond and intermolecular interaction force are strongly influenced by the charge bias (polarity) of the functional group. Urethane groups show strong hydrogen bonds and intermolecular interaction forces, both from their structure and from functional groups such as amide groups having the same nitrogen element. Therefore, by setting UrcY to 2.0 atomic% or more, a sufficient chemical bond is formed even between the silicone resin and the surface layer, and deterioration of interlayer adhesion under high temperature and high humidity can be suppressed. Further, by setting UrcY to 4.0 atomic% or less, it is possible to suppress the increase in the hardness of the surface layer and to reduce the stress applied to the toner. On the other hand, when UrcY is less than 2.0 atomic%, the chemical bond strength between the silicone resin and the surface layer is lowered, and the interlaminar adhesion may be deteriorated particularly under high temperature and high humidity. On the other hand, if UrcY is larger than 4.0 atomic%, the hardness of the surface layer is excessively increased, which may worsen image defects caused by toner fixation when an image is repeatedly output.

Further, UrcY of the surface layer in the present invention is a value measured by X-ray photoelectron spectroscopy called ESCA (or XPS). ESCA is an analysis method capable of identifying the elemental composition and chemical bonding state in the vicinity of the very surface of the developing roller surface layer (several tens of nm in the depth direction). Furthermore, it is an analytical method capable of quantifying the distribution of elemental composition and chemical bonding state in the film thickness direction while edging the surface layer with high accuracy using fullerene (C ₆₀ ) ions. Details regarding the definition and measurement method of UrcY of the surface layer measured by ESCA (X-ray photoelectron spectroscopy) in the present invention will be described later.

  Preferred upper limits of each value of (1) surface layer thickness (t), (2) Martens hardness HM, and (3) nitrogen atom% (UrcY) derived from urethane groups in Y measured by ESCA as defined in the present invention And the lower limit is independent. However, these specified values in the present invention may affect each other and move in conjunction with each other. For example, as the surface layer thickness (t) increases, the Martens hardness HM also increases. UrcY is a value indicating the atomic% of the nitrogen element derived from the urethane group, and this value correlates with the crosslinking density of the urethane resin. UrcY in the present invention indicates the nitrogen atom% of the surface layer near the resin layer interface, and strictly speaking, the increase in UrcY contributes to an increase in Martens hardness HM, although it differs from the hardness of the surface layer as a bulk. From the above viewpoint, it is necessary to strictly control (1) the film thickness (t) of the surface layer, (2) Martens hardness HM, and (3) UrcY in order to exhibit the effects of the present invention. In particular, the Martens hardness in the present invention is a value measured at a temperature of −10 ° C. As a basic characteristic of polymers and rubber materials, it is known that reversibly transitions to the rubber and glass states at the glass transition temperature, and the mechanical properties are remarkably increased in the glass state. In order to satisfy the range of Martens hardness defined in the present invention, the surface layer needs to be in a rubber state at a measurement temperature of −10 ° C. However, when the atomic percentage of the nitrogen element derived from the urethane group as measured by ESCA is in the range of 2.0% or more as the surface layer bulk, it is difficult to satisfy the range of Martens hardness defined in the present invention. Therefore, in order to simultaneously achieve the Martens hardness and UrcY defined in the present invention, the nitrogen atom% as the bulk of the surface layer needs to be lower than the vicinity Y of the silicone resin layer interface. In other words, nitrogen element is inclined and unevenly distributed in the urethane resin of the surface layer, it has nitrogen element derived from high concentration urethane group in the vicinity of the silicone resin layer interface, and the surface layer hardness as a bulk is flexible. However, this is a requirement necessary for manifesting the effects of the present invention.

  That is, it is desirable to select a resin material as appropriate so that the surface layer containing the cured polyurethane resin has the above physical properties. First, the cured polyurethane resin in the present invention will be described. The term “polyurethane” as used herein is not a name indicating a polymer having a single composition, but a general term for polymers containing urethane bonds, 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.

  Examples of the cured polyurethane resin include those obtained from a polyol and an isocyanate compound. The polyurethane resin in the present invention is preferably formed from the following three types of resin raw materials from the viewpoint of functional separation, in particular, the uneven distribution of nitrogen group concentration derived from urethane groups and the achievement of a flexible surface layer as a bulk. .

  (A) polyol, (B) prepolymer type isocyanate, (C) low molecular type isocyanate compound. By appropriately selecting and blending these materials in accordance with the physical properties of each material, the effects of the present invention can be expressed more effectively.

  Specific examples of the polyol (A) are given below. Polycarbonate polyol, acrylic polyol, caprolactone polyol, polyether polyol, polyester polyol, polyolefin polyol or a mixture thereof. In addition, prepolymer polyols obtained by re-elongating these polyols with isocyanate can also be suitably used. Among these, polyether polyol, polyester polyol or a mixture thereof is preferable.

  As the polyether polyol, a polyurethane ether polyol prepolymer is preferable from the viewpoint of optimizing the polarity difference between (B) and (C) described later, and balancing the mechanical properties and flexibility of the surface layer. Examples of the raw material polyether polyol include polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG), and a copolymer of THF and neopentyl glycol (PTXG).

  As the polyester polyol, a polyester polyol obtained by direct esterification reaction or ring-opening polymerization reaction can be suitably used. 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.

  In the present invention, a polyester polyol using 3-methyl-1,5-pentanediol as a raw material is particularly preferable. 3-methyl-1,5-pentanediol exhibits a specifically low melting point (-50 ° C.) as compared to the melting point of general polyhydric alcohol (−10 ° C. to 200 ° C.). Therefore, since it is easy to control the crystallinity in the soft segment having an ester group in the urethane resin, it contributes to the expression of mechanical properties by improving the compatibility with the resin materials (B) and (C). Furthermore, polycaprolactone diol obtained by ring-opening polymerization reaction using ε-caprolactone as a raw material, or ester polyol synthesized by prepolymerizing polycaprolactone diol is also particularly preferable. Among the above-mentioned polycaprolactone diols, those having a non-crystalline or low melting point property are particularly preferred from the viewpoints of compatibility with the resin materials (B) and (C) and solubility in a solvent.

  In the polyester polyol, 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 the polyester polyol does not contain a urethane group in the structure, it is preferably in the range of 1000 ≦ Mn ≦ 4000. When Mn is 1000 or more, an increase in Martens hardness HM can be suppressed, and toner adhesion can be more effectively suppressed when an image is repeatedly output in a low-temperature and low-humidity environment. On the other hand, when Mn is 4000 or less, a decrease in Martens hardness HM can be suppressed, and an increase in the deformation amount of the developing roller can be more effectively suppressed. Further, it is possible to suppress the decrease in UrcY and suppress the deterioration of interlayer adhesion when left for a long period of time in a high temperature and high humidity environment. Moreover, when it is a prepolymer-type polyol which contains a urethane group in a structure, it is preferable to exist in the range of 3000 <= Mn <= 10000.

  Although the prepolymer type isocyanate compound (B) in this invention is not specifically limited, The following can be illustrated as a hard segment part. Diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 3,3′-dimethylbiphenyl-4,4′-diisocyanate, xylylene diisocyanate, trimethylhexamethylene diisocyanate, tolylene diisocyanate, naphthylene diisocyanate, paraphenyl diisocyanate, hexamethylene diisocyanate , Polymethylene polyphenyl polyisocyanate, copolymers thereof, block bodies or mixtures thereof. Among those exemplified above, diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 1,5-naphthalene diisocyanate, and tetramethyl xylylene diisocyanate having a benzene ring in the structure are relatively high in polarity and will be described later ( From the viewpoint of the difference in polarity from C). Further, the soft segment portion (modified portion) is not particularly limited, but prepolymer type isocyanate containing an ether group component and an ester group component in the modified portion is preferable. This is because it is easy to optimize the mechanical properties of the surface layer, to adjust the compatibility with the polyol (A) and the polarity difference with the later-described (C). Furthermore, the same material as the above-mentioned polyol can be suitably used for the modified part.

  Although it does not specifically limit as a low molecular type isocyanate type compound (C) in this invention, The thing similar to the material enumerated as a hard segment part of a prepolymer type isocyanate (B) can be used. Furthermore, among the examples exemplified above, an aliphatic isocyanate having a lower polarity than an aromatic isocyanate is preferable from the viewpoint of a difference in polarity from (B). For example, isophorone diisocyanate, hexamethylene diisocyanate, or uretdione and isocyanurate which are dimers and trimers thereof can be preferably used. Further, the low molecular weight type is preferable because it tends to be unevenly distributed at the interface and a sufficient NCO% content per unit volume can be obtained.

  Here, the resin materials (A), (B), and (C) will be described. The polyurethane resin in the present invention has a configuration in which the concentration of nitrogen groups derived from urethane groups is unevenly distributed near the silicone resin interface, and the surface layer is flexible as a bulk. In order for the nitrogen element derived from the urethane group to be present in a high concentration near the silicone resin interface, (1) a method of increasing the atomic percentage of the nitrogen element derived from the urethane group as a whole surface layer bulk, or (2) only in the vicinity of the interface There are two methods of uneven distribution of nitrogen atom% derived from urethane groups. However, since the former means induces an increase in Martens hardness HM, it is difficult to achieve the effects of the present invention. Therefore, it is preferable to use the latter means. In general, when resin materials having different structures are mixed as a characteristic of the resin material, a resin material having a low polarity tends to move to the interface. However, when the polarity difference between the resins is too large, the resins are not compatible with each other and the curing reaction is difficult to proceed, and the mechanical properties may be significantly reduced. Furthermore, since it is difficult to form a chemical bond between layers, interlayer adhesion may be significantly reduced. In the present invention, the polarity of the resin material (C) is preferably lower than that of the resin material (B), and the polarity difference between (A), (B) and (C) is preferably in an appropriate range. Therefore, in order to achieve a high level balance between the interlaminar adhesion and mechanical properties of the silicone resin layer and the surface layer under high temperature and high humidity in the present invention, (A), (B) and (C) It is preferable to select the chemical structure as appropriate. Further, when the mass contents of the (B) and (C) in the urethane resin are defined as M (B) and M (C), respectively, the value of M (C) / M (B) is 0. It is preferably 10 or more and 0.25 or less. When the value of M (C) / M (B) is 0.10 or more, a decrease in UrcY can be suppressed and sufficient interlayer adhesion can be obtained. Further, by being 0.25 or less, it is possible to suppress an increase in hardness as a surface layer bulk and to suppress toner sticking when an image is repeatedly output in a low temperature and low humidity environment.

  The isocyanate compound is preferably blended with respect to the polyol compound so that the isocyanate index is in the range of 1.0 to 1.5. By blending within the above range, an increase in compression set due to unreacted polyol and an excessive increase in hardness can be more effectively suppressed. 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 polyol component. The isocyanate index in the present invention is calculated using the total number of [NCO] moles of (B) prepolymer type isocyanate and (C) low molecular type isocyanate compound.

  The developing roller according to the present invention will be described below with reference to FIG. The developing roller 1 is composed of a member in which one or more resin layers 3 are fixed to the outer peripheral surface of a columnar or hollow cylindrical shaft core 2 and the surface layer 4 is laminated on the outer peripheral surface of the resin layer 3. The surface layer 4 may have a multilayer structure.

  The shaft core body 2 has a strength capable of supporting the upper resin layer 3 and the surface layer 4 and transporting the toner (developer) to the photoconductor, and conductivity capable of becoming an electrode capable of moving the charged toner to the photoconductor. Anything is acceptable.

  The standard of the thickness of the resin layer 3 is 1 mm or more and 5 mm or less. The resin layer 3 may be a foam or a non-foam. In order for the developing roller to have an electric resistance value of the semiconductor region, the resin layer 3 preferably has conductivity. In order to have conductivity in the resin layer 3, it is preferable to contain a conductivity-imparting agent based on an ionic conduction mechanism or an electronic conduction mechanism. As the conductivity imparting agent, carbon black is preferable because good chargeability can be obtained.

  The surface layer 4 includes the polyurethane resin described above. When two or more surface layers are formed, at least the surface layer in contact with the resin layer must contain the above-described polyurethane resin. The surface layer may contain carbon black for imparting conductivity and controlling mechanical properties. As a standard of the content of carbon black in the surface layer, from the viewpoint of imparting conductivity in an appropriate range to the developing roller and controlling mechanical properties, 15 parts by mass or more with respect to 100 parts by mass of the resin component of the surface layer It is 40 parts by mass or less.

  The average particle size of the carbon black is preferably 15 to 40 nm in consideration of maintaining the strength of the surface layer of the developing roller and exhibiting appropriate conductivity. The DBP oil absorption of carbon black is preferably 60 to 180 ml / 100 g for the same reason. Furthermore, you may mix | blend 2 or more types of carbon black according to a required physical property.

  The surface layer 4 may contain spherical fine particles in order to impart an appropriate surface roughness to the surface of the developing roller. When the surface layer 4 contains spherical fine particles, it is easy to make the surface roughness of the surface of the developing roller uniform, and at the same time, even when the surface layer 4 is worn, the fluctuation of the surface roughness is reduced and the surface state is reduced. Can be held constant. The spherical fine particles preferably have a volume average particle size of 8 to 30 μm. The content of the spherical fine particles is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the resin of the surface layer 4.

  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.

  As a method for producing the developing roller of the present invention, first, the resin layer 3 is a composition containing the uncured rubber component of the silicone rubber, a conductivity imparting agent, and other components as necessary (hereinafter referred to as uncured rubber composition). A coating solution is prepared from the product. And the method of forming a coating film using this coating liquid and hardening this can be mentioned. Examples of the coating method include a dip coating method, a blade coating method, a coating method using an annular coating tank, and a coating method using a ring-shaped coating head.

  As a method for forming the surface layer, a composition containing the uncured binder resin and the surface layer material of other components (hereinafter 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.

  For forming the coating film, a coating method such as spraying, dipping, or roll coating can be used. Further, when dip coating is used for 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 tank has a cylindrical shape having an inner diameter slightly larger than the outer diameter of the roller 6 on which the resin layer is formed and a depth longer than the axial length of the roller 6, and is set with the axial direction vertical. . 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 surface layer forming paint 10 through a pipe 13, 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 surface layer forming paint 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 surface layer on the resin layer using such a coating device, the pump 11 is driven and the surface layer forming coating material 10 stored in the stirring tank 8 is passed through the pipes 12 and 13 to the immersion tank 5. Supply. The elevating device 15 is driven, the elevating plate 16 is lowered, and the roller 6 is caused to enter the immersion tank 5 filled with the surface layer forming paint 10. The surface layer forming coating material 10 overflowing from the upper end 5 a of the immersion tank due to the entrance of the roller 6 is received by the liquid receiving portion 7 and returned to the stirring tank 8 through the pipe 9. Thereafter, the elevating device is driven to raise the elevating plate, and the roller 6 is retracted from the 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 surface layer is formed. As a method for curing and drying, either heating or electron beam irradiation may be used.

  FIG. 3 shows a process cartridge which can be attached to and detached from the electrophotographic apparatus provided with the developing roller. The process cartridge 17 can be formed as 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 image forming apparatus shown in FIG. 4.

  FIG. 4 is a cross-sectional view showing a schematic configuration of an image forming apparatus using a developing roller and a process cartridge having the developing roller according to the present invention. The image forming apparatus shown in FIG. 4 includes a developing device 22 including a developing roller 1, a toner supply roller 19, toner 20 and a developing blade 21, a photoconductor 18, a cleaning blade 26, a waste toner container 25, and a charging member 14. An all-in-one process cartridge 17 is detachably mounted. 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 being applied with toner by a developing device 22 disposed in contact with the photoreceptor 18 and visualized as a toner image.

  Development is so-called reversal development in which a toner image is formed on the exposed portion. The visualized toner image on the photoconductor 18 is transferred to a paper 34 as a recording medium by a transfer roller 29 as a transfer member. The paper 34 is fed into the apparatus through a paper feed roller 35 and a suction roller 36 and is transported between the photoconductor 18 and the transfer roller 29 by an endless belt-shaped transfer transport belt 32. The transfer conveyance belt is operated by a driven roller 33, a driving roller 28, and a tension roller 31. A voltage is applied to the transfer roller 29 and the suction roller 36 from a bias power source 30. The paper 34 to which the toner image has been transferred is subjected to fixing processing by the fixing device 27, discharged outside the device, and the printing operation is completed. On the other hand, the untransferred toner remaining on the photosensitive member 18 without being transferred is scraped off by a cleaning blade 26 which is a cleaning member for cleaning the surface of the photosensitive member, and is stored in a waste toner container 25 and cleaned. The body 18 repeats the above action. The developing device 22 is a developer container that contains a non-magnetic toner 20 as a one-component developer, and a developer carrier that is located in an opening extending in the longitudinal direction in the developer container and is disposed opposite to the photosensitive member 18. And a developing roller 1. Further, the electrostatic latent image on the photoconductor 18 is developed and visualized. By applying a voltage higher than the voltage applied to the developing roller 1 to the developing blade 21, the toner layer on the developing roller can be controlled. For this purpose, the developing blade 21 is preferably a thin plate of SUS or phosphor bronze. A voltage is applied to the developing roller 1 and the developing blade 21 from the bias power supply 30, 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 10 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 contacts the photosensitive member 18 while rotating, and the electrostatic latent image formed on the photosensitive member 18 is developed with toner coated on the developing roller 1 to form an image.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

[Production of Resin Layer Roller 1]
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.

A mixture of the following components was used as the base material for the liquid silicone rubber.
-Dimethylpolysiloxane (1) 50 parts by mass (Vinyl groups are substituted at both ends, and 99 mol% or more of the main chain is a repeating unit of dimethylpolysiloxane. Weight average molecular weight (Mw) = 20,000)
-Dimethylpolysiloxane (2) 50 parts by mass (Vinyl groups are substituted at both ends, and 99 mol% or more of the main chain is a repeating unit of dimethylpolysiloxane. Mw = 10,000,0)
Carbon black (1) 7 parts by mass (trade name: Raven 860 Ultra, manufactured by Columbian Chemical)

  This base material was prepared by blending 10 ppm of a isopropyl alcohol solution of 2% by mass of chloroplatinic acid as a curing catalyst with respect to the total of dimethylpolysiloxanes (1) and (2). On the other hand, 3 parts by mass of methyl hydrogen polysiloxane in the base material (amount that SiH group is 1.1 mol with respect to a total of 1 mol of vinyl groups contained in dimethylpolysiloxane (1) and (2)) Was prepared. And these were mixed by mass ratio 1: 1, and it was set as the unvulcanized silicone rubber.

  Next, the shaft core was placed in a mold, and the unvulcanized silicone rubber was injected into a cavity formed in the mold. Subsequently, the mold was heated to cure and cure the unvulcanized silicone rubber at 150 ° C. for 15 minutes, and then demolded after cooling. Thereafter, the mixture was further heated at 180 ° C. for 1 hour to complete the curing reaction, and a resin layer was provided around the shaft core body. The produced resin layer roller 1 had a diameter of 16 mm and an Asker C hardness of 55 degrees.

[Production of Resin Layer Roller 2]
Resin layer roller in the same manner as the resin layer roller 1 except that 100 parts by mass of dimethylpolysiloxane (3) was used instead of 50 parts by mass of dimethylpolysiloxane (1) and 50 parts by mass of dimethylpolysiloxane (2). 2 was produced. The dimethylpolysiloxane (3) has vinyl groups at both ends, 99 mol% or more of the main chain is a repeating unit of dimethylpolysiloxane, and Mw is 60,000. The produced resin layer roller 2 had a diameter of 16 mm and an Asker C hardness of 62 degrees.

[Production of Resin Layer Roller 3]
Resin layer roller in the same manner as resin layer roller 1 except that 100 parts by mass of dimethylpolysiloxane (4) was used instead of 50 parts by mass of dimethylpolysiloxane (1) and 50 parts by mass of dimethylpolysiloxane (2). 3 was produced. The dimethylpolysiloxane (4) has vinyl groups substituted at both ends, 99 mol% or more of the main chain is a repeating unit of dimethylpolysiloxane, and Mw is 40,000. The produced resin layer roller 3 had a diameter of 16 mm and an Asker C hardness of 65 degrees.

[Production of resin layer roller 4]
Resin layer roller in the same manner as resin layer roller 1 except that 100 parts by mass of dimethylpolysiloxane (5) was used instead of 50 parts by mass of dimethylpolysiloxane (1) and 50 parts by mass of dimethylpolysiloxane (2). 4 was produced. The dimethylpolysiloxane (5) has vinyl groups substituted at both ends, 99 mol% or more of the main chain is a repeating unit of dimethylpolysiloxane, and Mw is 25,000. The produced resin layer roller 4 had a diameter of 16 mm and an Asker C hardness of 70 degrees.

  Then, although the synthesis method of the prepolymer type polyol and isocyanate compound in the Example and comparative example of this invention is illustrated and demonstrated concretely, this invention is not limited to these.

[Synthesis of Prepolymer Type Polyol 1 (Pre-P1)]
・ 100 parts by mass of polytetramethylene glycol (trade name: PTG1000SN, manufactured by Hodogaya Chemical Co., Ltd.)
・ Isocyanate compound 22 parts by mass (trade name: Millionate MT, manufactured by Nippon Polyurethane Industry Co., Ltd.)

  The above components are mixed stepwise in a MEK solvent and reacted at 80 ° C. for 6 hours under a nitrogen atmosphere to obtain an ether-modified prepolymer polyol 1 (Pre-P1) having a number average molecular weight Mn = 4,000. Obtained.

[Synthesis Method of Prepolymer Type Isocyanate 1 (Pre-BI1)]
Esterdiol 100 parts by mass (consisting of adipic acid and 3-methyl-1,5-pentanediol. Mn = 1000)
(Product name: P-1010, manufactured by Kuraray Co., Ltd.)
・ 96 parts by mass of polymethylene polyphenylene polyisocyanate (trade name: Cosmonate M-100, manufactured by Mitsui Chemicals Polyurethanes)

  The above components were heated and reacted at 90 ° C. for 2 hours in a nitrogen atmosphere. Thereafter, butyl cellosolve was added to a solid content of 65% by mass. Thereafter, 25 parts by mass of MEK oxime was added dropwise under a reaction temperature of 50 ° C. to obtain ester-modified prepolymer type isocyanate 1 (Pre-BI1).

[Synthesis Method of Prepolymer Type Isocyanate 2 (Pre-BI2)]
・ 100 parts by weight of polypropylene glycol (trade name: Exenol 720, manufactured by Asahi Glass Co., Ltd.)
-Tolylene diisocyanate 105 parts by mass (trade name: Takenate D-101A, manufactured by Mitsui Chemicals Polyurethanes)

  The above components were heated and reacted at 90 ° C. for 2 hours in a nitrogen atmosphere. Thereafter, butyl cellosolve was added to a solid content of 72% by mass. Thereafter, 28 parts by mass of MEK oxime was added dropwise under a reaction temperature of 50 ° C. to obtain ether-modified prepolymer type isocyanate 2 (Pre-BI2).

[Synthesis Method of Prepolymer Type Isocyanate 3 (Pre-BI3)]
Esterdiol 100 parts by mass (consisting of adipic acid and 3-methyl-1,5-pentanediol. Mn = 1000)
・ 134 parts by mass of polymethylene polyphenylene polyisocyanate (trade name: Cosmonate M-100, manufactured by Mitsui Chemicals Polyurethanes)

  The above components were heated and reacted at 90 ° C. for 2 hours in a nitrogen atmosphere. Thereafter, butyl cellosolve was added to a solid content of 70% by mass. Thereafter, 35 parts by mass of MEK oxime was added dropwise under a reaction temperature of 50 ° C. to obtain ester-modified prepolymer type isocyanate 3 (Pre-BI3).

[Synthesis Method of Prepolymer Type Isocyanate 4 (Pre-BI4)]
Esterdiol 100 parts by mass (consisting of sebacic acid and 3-methyl-1,5-pentanediol. Mn = 1000)
(Product name: P-1050, manufactured by Kuraray Co., Ltd.)
・ 80 parts by mass of polymethylene polyphenylene polyisocyanate (trade name: Cosmonate M-100, manufactured by Mitsui Chemicals Polyurethanes)

  The above components were heated and reacted at 90 ° C. for 2 hours in a nitrogen atmosphere. Thereafter, butyl cellosolve was added to a solid content of 70% by mass. Thereafter, 24 parts by mass of MEK oxime was added dropwise under a reaction temperature of 50 ° C. to obtain ester-modified prepolymer type isocyanate 4 (Pre-BI4).

[Synthesis Method of Prepolymer Type Isocyanate 5 (Pre-BI5)]
・ 100 parts by mass of polytetramethylene glycol (trade name: PTG1000SN, manufactured by Hodogaya Chemical Co., Ltd.)
・ 85 parts by mass of polymethylene polyphenylene polyisocyanate (trade name: Cosmonate M-200, manufactured by Mitsui Chemicals Polyurethanes)

  The above components were heated and reacted at 90 ° C. for 2 hours in a nitrogen atmosphere. Thereafter, butyl cellosolve was added to a solid content of 70% by mass. Thereafter, 27 parts by mass of MEK oxime was added dropwise under a reaction temperature of 50 ° C. to obtain ether-modified prepolymer type isocyanate 5 (Pre-BI5).

[Synthesis Method of Prepolymer Type Isocyanate 6 (Pre-BI6)]
・ 100 parts by mass of polytetramethylene glycol (trade name: PTG1000SN, manufactured by Hodogaya Chemical Co., Ltd.)
・ 125 parts by mass of polymethylene polyphenylene polyisocyanate (trade name: Cosmonate M-200, manufactured by Mitsui Chemicals Polyurethanes)

  The above components were heated and reacted at 90 ° C. for 2 hours in a nitrogen atmosphere. Thereafter, butyl cellosolve was added to a solid content of 70% by mass. Thereafter, 35 parts by mass of MEK oxime was added dropwise under a reaction temperature of 50 ° C. to obtain ether-modified prepolymer type isocyanate 6 (Pre-BI6).

Subsequently, in the examples and comparative examples of the present invention, the surface layer-forming coating liquids shown below are the polyols shown below and the above-mentioned prepolymer type polyol (A), prepolymer type isocyanate (B) and low molecular type isocyanate compound. Prepared using starting material consisting of (C).
<Polyol>
・ Polycaprolactone polyol (trade name: Plaxel L-212AL, manufactured by Daicel Chemical Industries, Ltd.)
Ester polyol (trade name: NS-2400, consisting of 3-methyl-1,5-pentanediol and adipic acid, manufactured by ADEKA Corporation)
Ester polyol (trade name: P-3010, P-4010, consisting of 3-methyl-1,5-pentanediol and adipic acid. Kuraray Co., Ltd.)
Ester polyol (trade names: P-1050, P-2050, P-3050, consisting of 3-methyl-1,5-pentanediol and sebacic acid, manufactured by Kuraray Co., Ltd.)
Ester polyol (trade name: YG-108, consisting of 1,6-hexanediol, adipic acid and isophthalic acid, manufactured by ADEKA Corporation)
<Low molecular isocyanate compound>
・ Low molecular block type isophorone diisocyanate (trade name: B-874N, manufactured by Mitsui Chemicals Polyurethanes)
・ Low molecular block type hexamethylene diisocyanate (trade name: B-882N, manufactured by Mitsui Chemicals Polyurethanes)
Isophorone diisocyanurate (Brand name: B-1370, manufactured by Mitsui Chemicals Polyurethanes)
・ Hexamethylene diisocyanurate (trade name: TPAB80E, manufactured by Mitsui Chemicals Polyurethanes)

"Preparation of surface layer forming coating liquid (1)"
Esterdiol 100 parts by mass (trade name: P-2050, manufactured by Kuraray Co., Ltd., consisting of sebacic acid and 3-methyl-1,5-pentanediol. Mn = 2,000)
・ Pre-BI1 102 mass parts ・ Low molecular block type isophorone diisocyanate 9.2 mass parts (Brand name: B-874N, manufactured by Mitsui Chemicals Polyurethanes)

  As a material for the coating liquid for forming the surface layer, the above components were mixed to obtain a resin component. Subsequently, 24 parts by mass of carbon black (trade name: X-15, manufactured by Asahi Carbon Co., Ltd.) and MEK were added to 100 parts by mass of the solid content of the resin component, and the mixture was 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) 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, 50 parts by mass of urethane resin particles (trade name: Art Pearl CF-600T, manufactured by Negami Kogyo Co., Ltd.) are added as resin particles for adjusting the roughness to 100 parts by mass of the solid content of the resin component, and further for 1 hour. Distributed. Next, this solution was diluted with MEK so as to have a solid content of 18% by mass, and this solution was filtered through a 300-mesh screen to obtain a surface layer-forming paint (1).

“Preparation of surface layer forming coating liquids (2) to (37)”
The surface layer forming coating liquids (2) to (37) in the present invention were prepared in the same manner as the surface layer forming coating liquid (1) except that the above starting materials were used. In addition, preparation of paint solid content was performed by adjusting the addition amount of MEK. Table 1 shows parts by mass and physical properties of the starting materials used for forming each surface layer.

[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. I did it. The distance between the elastic layer surface and the excimer lamp at the time of irradiation was 2 mm. Then, the developing roller was produced by forming the coating material for surface layer formation.

  In the formation of the surface layer, 250 cc of the surface layer forming paint (1) maintained at a liquid temperature of 23 ° C. was injected from the lower side of the cylinder having an inner diameter of 32 mm and a length of 300 mm, and overflowed from the upper end of the cylinder. The liquid was again circulated below the cylinder. The resin layer (1) is immersed in a cylinder at an intrusion speed of 100 mm / s and stopped for 10 seconds, and then the resin layer (1) is pulled up under conditions of an initial speed of 400 mm / s and an final speed of 200 mm / s for 60 minutes. Let dry naturally. Next, the raw material for the surface layer was cured by heat treatment at 150 ° C. for 2 hours to produce the developing roller (1) of Example 1 having a surface layer with a thickness of 4 μm.

  Subsequently, the measurement method of UrCY using ESCA, the composition analysis using FT-IR, and the measurement method of Martens hardness (HM) in Examples and Comparative Examples of the present invention will be described below.

[Evaluation of developing roller surface layer / roller physical properties]
(UrcY measurement method)
The value of UrcY in the present invention is defined as the atomic% of the nitrogen element derived from the urethane group measured by ESCA at a depth of 7t / 8 from the outermost surface of the surface layer, where t is the thickness of the surface layer. The Further, the urethane group in the present invention includes functional groups associated with the urethane bond such as biuret bond, allophanate bond, and urea bond. Judgment whether the value of UrCY at this time is derived from a urethane group or another functional group can be quantitatively evaluated by using a Fourier transform-infrared absorption (FT-IR) spectrum. The FT-IR spectrum analysis of the present invention was evaluated using Nicolet AVATAR 360 FT-IR manufactured by JASCO Corporation. As the measurement sample, a toner and an external additive adhering to the surface of the developing roller were wiped off with a cloth soaked with isopropyl alcohol after image evaluation described later, and then the urethane surface layer was thinly scraped with a biocutter.

For example, the surface layer of the developing roller (1) were evaluated in FT-IR, only the spectrum due to the ester group (1200 cm ^-1) and urethane group (1710 cm ^-1) was confirmed.

  Further, UrCY defined in the present invention was evaluated by ESCA analysis after edging the surface layer under the following conditions. In addition, ESCA analysis was performed using Quantum 2000 of ULVAC-PHI Co., Ltd. under the following conditions.

[Edging conditions]
Sputtering Ion; C ₆₀ ion sputtering acceleration voltage; 4 kV
・ Raster size: 2 × 0.5mm ²

[ESCA analysis conditions]
・ X-ray source; Monochrome AI Kα
-Xray Setting; 100 μmφ (25 W (15 KV))
・ Photoelectron extraction angle: 45 degrees ・ Neutralization conditions: Combined use of neutralizing gun and ion gun ・ Analysis area: φ100 μm
・ Pass Energy; 23.5eV
・ Step size: 0.1 eV

  For example, as a result of ESCA analysis at a position at a depth of 7t / 8 from the surface layer of the developing roller (1), C, N, O and Si were detected as constituent elements. Further, from the analysis results of FT-IR that the atomic% of each was 56.8%, 2.0%, 16.8%, 24.3%, UrcY of the developing roller (1) was 2.0%. In the measurement of UrcY in the present invention, three different places were measured and the arithmetic average value was used. Tables 4 and 5 show the results of the developing rollers produced in each example and comparative example.

(Martens hardness measurement method)
The Martens hardness (HM) is measured according to ISO14577-1 (2002) except that the following conditions are used. As a measuring device, Picodenter HM500 (trade name, manufactured by Fisher Instruments Co., Ltd.) was used. The developing roller and the measuring device were left in an environment at a temperature of −10 ° C. for 24 hours, and the measurement was performed. At the position 5 mm from both ends and the central portion in the longitudinal direction, measurement was performed at three points in different circumferential directions, and an arithmetic average of nine points was calculated using the following formula (2) to obtain the Martens hardness of the developing roller. Tables 4 and 5 show the Martens hardness of the developing roller produced in each example and comparative example.

〔Measurement condition〕
・ Measurement indenter shape: Triangular pyramid indenter (115 ° ridge spacing, Belkovic type)
・ Measurement indenter material: Diamond ・ Measurement temperature: −10 ° C.
・ Loading speed and unloading speed; 0.050 mN / 10 s
・ Loading time: 5.0 s
Indentation depth: t / 4 μm (t is the film thickness of the surface layer)

HM (N / mm ² ) = (test load (N)) / (surface area of the diamond indenter under the test load (mm ² )) = F / (26.43 × h ² ) (2)
[F: push-in load, h: push-in amount of indenter]

[Examples 2 to 27]
The developing rollers (2) to (27) in Examples 2 to 27 of the present invention are manufactured in the same manner as the developing roller (1) of Example 1 by combining the resin layer roller and the surface layer forming coating liquid. did. In addition, evaluation of various characteristics and image evaluation were performed in the same manner as the developing roller (1) of Example 1. The results are shown in Table 4.

[Example 28]
As a surface treatment method for the resin layer roller, a surface layer having a thickness of 10 μm was used in the same manner as in Example 14 except that a corona discharge treatment apparatus (Kasuga Denki Co., Ltd.) was used under the following conditions. A developing roller (28) of Example 28 having In addition, evaluation of various characteristics and image evaluation were performed in the same manner as the developing roller (1) of Example 1. The results are shown in Table 4.

[Corona treatment conditions]
Table 2 shows the corona treatment conditions.

[Example 29]
As a surface treatment method for the resin layer roller, a surface having a thickness of 10 μm was used in the same manner as in Example 14 except that flame treatment was performed using a flame treatment apparatus FTS-401 (manufactured by Argon Gas) under the following conditions. A developing roller (29) of Example 29 having a layer was produced. In addition, evaluation of various characteristics and image evaluation were performed in the same manner as the developing roller (1) of Example 1.

[Flame treatment conditions]
Table 3 shows the flame treatment conditions.

[Example 30]
A developing roller (30) of Example 30 having a surface layer having a thickness of 10 μm was produced in the same manner as in Example 14 except that the surface layer was formed without performing the surface treatment of the resin layer. In addition, evaluation of various characteristics and image evaluation were performed in the same manner as the developing roller (1) of Example 1.

[Comparative Examples 1 to 12]
Developing rollers according to Comparative Examples 1 to 12 having the configurations described in Table 5 were produced. Evaluation of various characteristics and image evaluation of these developing rollers were performed in the same manner as in Example 1. The results are shown in Table 5.

  Hereinafter, image evaluation methods in Examples and Comparative Examples will be described.

[Image evaluation]
[Evaluation of image streaks due to long-term contact of developing blade under high temperature and high humidity]
The developing roller was incorporated in an electrophotographic process cartridge EP-85K (trade name, manufactured by Canon Inc., color: black), and 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 30 ° C. and a humidity of 85% RH. Then, in the same environment, the electrophotographic process cartridge was installed in a printer manufactured by Canon LBP5500 (trade name). The modified machine uses a phosphor bronze blade having a thickness of 100 μm as a developing blade, modified so that a blade bias can be applied to the developing blade, and modified so that full color printing can be performed at 40 rpm. The blade bias was set to −150 V with respect to the development bias, and three solid black images were output. In this solid black image, image streaks due to the deformation of the developing roller due to contact with the developing blade being left standing were evaluated under the following evaluation conditions. The results for the developing rollers produced in each example and comparative example are shown in the table.

A: Image streaks due to the deformation of the developing roller are hardly confirmed in the solid black image.
B: Slight image streaks due to deformation of the developing roller can be confirmed in the solid black image.
C: Image streaks due to deformation of the developing roller can be clearly confirmed in a solid black image. However, when a solid black image is formed again after leaving the cartridge in a normal temperature and normal humidity environment (temperature 23 ° C., humidity 50% RH) for 24 hours, no image streak is observed.
D: Image streaks due to the deformation of the developing roller can be clearly confirmed in the solid black image. Even if the cartridge is left for 24 hours in a normal temperature and humidity environment (temperature 23 ° C., humidity 50% RH) and then a solid black image is formed again, image streaks are observed.

[Evaluation of endurance fog in a low-temperature, low-humidity environment (temperature: 15 ° C., humidity: 10% RH)]
After image streak evaluation by long-term contact of the developing blade in a high temperature and high humidity environment, the developing roller is incorporated into a new electrophotographic process cartridge, and this electrophotographic process cartridge is left in an environment of temperature 10 ° C. and humidity 10% RH for 24 hours. did. In the same environment, the electrophotographic process cartridge was installed in a modified Canon printer LBP5500 (trade name) in this environment, and continuous image output was performed at a printing rate of 1% under a bias condition of -200V with respect to the development bias. Went. Durability fog was evaluated by measuring the number of output sheets in which fog exceeding 3% was observed in the solid white portion, and performing the following evaluation criteria. In addition, the reflectance of the non-printed portion (reference) and the solid white portion of the print range is measured for every 1000 sheets of output using a Macbeth reflection densitometer. " The results for the developing rollers produced in each example and comparative example are shown in the table.

A: The fog of 3% or more is not confirmed even when printing 25000 sheets by continuous printing.
B: Fog of 3% or more was confirmed on continuous printing 20000 sheets or more and less than 25000 sheets.
C: Fog of 3% or more was confirmed on continuous printing of 10000 or more and less than 20000.
D: Fog of 3% or more was confirmed on less than 10,000 continuous prints.

[Evaluation of adhesion between resin layers]
After the above image evaluation, the adhesion was evaluated by observing film peeling between the resin layer of the developing roller and the surface layer. The developing roller was taken out of the electrophotographic process cartridge after image evaluation, and left in an environment of a temperature of 60 ° C. and a humidity of 90% 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. After leaving, in the same environment, cellophane tape No. 1 was compliant with JISK5400 (1990). Using 232 (trade name, manufactured by 3M), the adhesiveness between the resin layer and the surface layer was evaluated according to the following criteria by a cross-cut test method. The results for the developing rollers produced in each example and comparative example are shown in the table.

A: The number of peeled cells per 100 cells is 0
B: The number of peeled cells per 100 cells is 1 or more and less than 5 C: The number of peeled cells per 100 cells is 5 or more and less than 20 D: The number of peeled cells per 100 cells is 20 or more.

  From Tables 4 and 5, it is clear that satisfying the conditions defined in the present invention shows good interlayer adhesion between the silicone resin layer and the surface layer even when stored for a long time in a high temperature and high humidity environment. In addition, it is clear that both the image streaks due to the deformation of the developing roller under high temperature and high humidity and the suppression of toner sticking onto the surface layer of the developing roller when repeatedly outputting images under low temperature and low humidity can be achieved. In particular, in the developing rollers produced in Examples 13 and 14, interlayer adhesion in a high-temperature and high-humidity environment, suppression of image streaks due to deformation of the developing roller, and suppression of toner adhesion when repeatedly outputting images at low temperatures and low humidity Obviously, we were able to achieve this at a high level.

  On the other hand, the developing rollers produced in Comparative Examples 1 and 2 had low Martens hardness HM, and image streaks were observed as the amount of deformation of the developing roller increased in a high temperature and high humidity environment. The developing rollers prepared in Comparative Examples 3 and 4 were too thick, and the Martens hardness HM was excessively increased. When repeated images were output in a low-temperature and low-humidity environment, fogging was confirmed. Further, the developing roller produced in Comparative Example 5 has low UrcY, and not only significant delamination was confirmed when left in a high temperature and high humidity environment for a long period of time, but also along with an increase in the deformation amount of the developing roller. The image streaks were confirmed. On the contrary, since the developing roller produced in Comparative Example 6 had UrcY that was too high, it was confirmed that fog was deteriorated when repeated images were output in a low-temperature and low-humidity environment. The developing roller produced in Comparative Example 7 had a low UrcY like the developing roller of Comparative Example 5, and significant delamination was confirmed when left for a long period in a high temperature and high humidity environment. As with the developing roller of Comparative Example 6, the developing roller produced in Comparative Example 8 had UrcY that was too high, and therefore, fogging was confirmed when repeated images were output in a low-temperature and low-humidity environment. Since the UrcY of the developing roller of Comparative Example 9 was too low, significant delamination was confirmed when left for a long period in a high temperature and high humidity environment. Furthermore, when an image is repeatedly output in a low-temperature and low-humidity environment, the surface layer is peeled off during image output, and it has not been possible to evaluate an image defect due to toner fixation. As with the developing roller of Comparative Example 10, since UrcY was too high, it was confirmed that fog was deteriorated when images were repeatedly output in a low temperature and low humidity environment. Since the developing roller produced in Comparative Example 11 had a Martens hardness HM that was too low, image streaks accompanying an increase in the amount of deformation of the developing roller in a high-temperature and high-humidity environment were confirmed. On the other hand, since the Martens hardness HM of the developing roller produced in Comparative Example 12 was too high, it was confirmed that fog was deteriorated when repeated images were output in a low temperature and low humidity environment.

DESCRIPTION OF SYMBOLS 1 Developing roller 2 Shaft core body 3 Resin layer 4 Surface layer

Claims (5)

In a developing roller having a shaft core, a resin layer provided around the shaft core, and a surface layer provided on the outer periphery of the resin layer,
The resin layer includes a silicone resin, the surface layer includes a polyurethane resin,
The surface layer has a temperature of −10 ° C., a load of 0.050 mN / 10 s, a load time of 5.0 s, and an indentation depth from the surface of the surface layer of t / 4 (where t is the thickness of the surface layer). The Martens hardness HM in the range of 3.0 to 4.5, and the atomic percentage of the nitrogen element derived from the urethane group at a position 7t / 8 from the surface of the surface layer is 2%. A developing roller characterized in that it is not less than 0.0 and not more than 4.0.   The developing roller according to claim 1, wherein the surface layer contains (A) a polyol, (B) a prepolymer type isocyanate, and (C) a low molecular type isocyanate compound.   When the mass contents of (B) and (C) are M (B) and M (C), respectively, the value of M (C) / M (B) is 0.10 or more and 0.25 or less. Item 3. The developing roller according to Item 1 or 2.   A process cartridge comprising the developing roller according to claim 1, which is detachable from an electrophotographic apparatus.   An electrophotographic apparatus comprising the developing roller according to claim 1 and a photoconductor.