JP5388554B2 - Developing roller, electrophotographic process cartridge and image forming apparatus using the same - Google Patents

Description

  The present invention relates to a developing roller used in an image forming apparatus such as a copying machine or a laser printer, an electrophotographic process cartridge using the developing roller, and an image forming apparatus.

  In a copying machine, a facsimile, and a printer using an electrophotographic system, a photosensitive drum is uniformly charged by a charging roller, and an electrostatic latent image is formed by a laser. Next, the developer in the developer container (hereinafter sometimes referred to as toner) is uniformly applied on the developer roller with a proper charge by the developer application roller and the developer regulating member, and the contact portion between the photosensitive drum and the developer roller. The developer is transferred (developed). Thereafter, the developer on the photosensitive drum is transferred onto a recording sheet by a transfer roller and fixed by heat and pressure. The developer remaining on the photosensitive drum is removed by a cleaning blade, and a series of processes is completed.

The characteristics required for the developing roller used in these image forming apparatuses include the following (1) and (2):
(1) Uniform and high chargeability to the developer,
(2) Uniform developer transportability.

  For the purpose of improving such characteristics, Patent Document 1 discloses a conductive shaft, an elastic layer formed on the outer periphery of the conductive shaft, and a surface layer formed on the outer periphery of the elastic layer. A developing roller having fine particles dispersed in the surface layer is disclosed.

  With the recent improvement in image quality of image forming apparatuses, the particle size of the developer used in the image forming apparatus has been reduced. Reducing the particle size of the developer is an effective means to further improve the graininess and character reproducibility among the image quality characteristics, but has a problem to be improved in specific image quality items, particularly fogging during durable printing. ing.

  That is, when the particle size of the developer is reduced, the surface area per unit mass of the developer increases, and the chance that each developer contacts with another developer, or with the developing roller or the developer regulating member increases. Tends to deteriorate. Further, when the particle size of the developer is reduced, the developer present in the gap between the developing roller and the developer regulating member increases, and a developer that does not move even when rubbed with the developer regulating member may be generated. . As a result, development roller fusion of the developer is promoted. Specifically, as a result of developer fusion occurring on the surface of the developing roller, fogging may occur due to a decrease in the charge amount of the developer.

  In order to prevent the developer from fusing to the developing roller, Patent Document 2 discloses a rubber composition in which particles formed from a release agent composed of reactive silicone oil or fluorine oil are dispersed in a fluorine rubber matrix. Has been proposed for use in forming the outermost layer of the developing roller.

Patent Document 3 proposes a developing roller in which an outermost layer is formed by a rubber composition in which silicone resin / silicone rubber particles having silicone oil are dispersed in a fluororubber matrix.
JP 2004-191561 A JP-A-9-87344 Japanese Patent Laid-Open No. 9-230689

  However, when the present inventors examined these developing rollers, although the fusing of the developer was improved, problems such as a decrease in image density were newly caused.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developing roller having improved fog and image density during durable printing, and to provide a high-quality electrophotographic process cartridge and an image forming apparatus using the developing roller. is there.

The present invention relates to a developing roller having a conductive shaft, an elastic layer on the outer periphery of the conductive shaft, and a surface layer on the outer periphery of the elastic layer.
The surface layer contains a polyurethane resin and porous resin particles having a specific surface area of ² to 100 m ² / g,
The porous resin particles include at least one selected from the group consisting of a fluorine compound that is liquid and non-reactive at a temperature of 23 ° C. and a silicone compound that is liquid and non-reactive at a temperature of 23 ° C., and
The arithmetic average particle diameter X (μm) of the porous resin particles, the film thickness T (μm) of the surface layer, the MD-1 hardness M (degrees) of the surface layer, and the compressive strength A of the porous resin particles (MPa) has the following relationships (a) to (e)
(A) 0.5 ≦ X / T ≦ 3.0
(B) 5 μm ≦ X ≦ 50 μm
(C) 2 μm ≦ T ≦ 25 μm
(D) 30 degrees ≦ M ≦ 43 degrees (e) 1.0 MPa ≦ A ≦ 5.0 MPa
It is related with the developing roller characterized by satisfying.

  The present invention also relates to an electrophotographic process cartridge comprising a developing roller and a developer regulating member in contact with the developing roller, wherein the developing roller is the developing roller according to the present invention. .

  The present invention also relates to an image forming apparatus comprising a developing roller and a developer regulating member in contact with the developing roller, wherein the developing roller is the developing roller according to the present invention.

  According to the present invention, it is possible to provide a developing roller with improved fog and image density during durable printing, and to provide an electrophotographic process cartridge and an image forming apparatus capable of stably forming a high-quality image. it can.

  Hereinafter, the present invention will be described in more detail.

  As shown in FIG. 1, the developing roller according to the present invention has at least one elastic layer 2 provided on the outer periphery of the conductive shaft body 1, and has a surface layer 3 on the outer periphery of the elastic layer 2. Yes.

Surface layer 3 is at least polyurethane resin and specific surface area contains a porous resin particles of 2m ² / g~100m ² / g.

  The porous resin particles include at least one selected from the group consisting of a non-reactive fluorine compound that is liquid at a temperature of 23 ° C. and a non-reactive silicone compound that is liquid at a temperature of 23 ° C.

  Further, the arithmetic average particle diameter X (μm) of the porous resin particles, the film thickness T (μm) of the surface layer, the MD-1 hardness M (degrees) of the surface layer, and the compression of the porous resin particles The strength A (MPa) satisfies the following relationships (a) to (e).

By adopting such a configuration, it is possible to improve the above problems, that is, fog and image density during durable printing.
(A) 0.5 ≦ X / T ≦ 3.0
(B) 5 μm ≦ X ≦ 50 μm
(C) 2 μm ≦ T ≦ 25 μm
(D) 30 degrees ≦ M ≦ 43 degrees (e) 1.0 MPa ≦ A ≦ 5.0 MPa.

  The present inventors have found that developer fusion occurs from the vicinity of a convex portion formed by particles contained and dispersed in the surface layer. Therefore, at least one of the non-reactive fluorine compound and the non-reactive silicone compound (hereinafter referred to as non-reactive fluorine compound / silicone compound) does not exist in the entire surface layer of the developing roller, but the developer fusing occurs. Only existed in the source. As a result, it was possible to improve the releasability between the developer and the developing roller surface while suppressing a decrease in image density. Furthermore, in order to improve the image density, the compression hardness of the particles contained / dispersed in the surface layer is increased, and the porous resin particles are used in the particles contained / dispersed in the surface layer, thereby By increasing the amount of the non-reactive fluorine compound / silicone compound present in the vicinity of the convex portion, it was possible to improve the releasability between the developer and the developing roller surface.

  As a result of studying to improve the fog at the time of durable printing which is the object of the present invention, it is important to delay the deterioration of the developer (also referred to as toner) on the developing roller and to prevent the developer from staying. I found out.

  That is, in order to improve fogging, it is important to reduce the number of frictions with other developers or other members per unit mass of the developer and to improve the releasability between the developer and the developing roller surface. The knowledge that there is.

  Here, the relationship between the arithmetic average particle diameter X of the porous resin particles dispersed in the surface layer and the film thickness T of the surface layer, and the arithmetic average particle diameter of the porous resin particles dispersed in the surface layer A change in the surface profile of the developing roller due to X will be described. A change in developer fusion to the developing roller due to the surface profile will be described. 2 and 3 are schematic views of a cross section near the surface of the developing roller. FIG. 2 shows changes in the surface profile due to X / T when the arithmetic average particle diameter X of the porous resin particles 30 is constant, and FIG. 3 satisfies 0.5 ≦ X / T ≦ 3.0. The change of the surface profile by the arithmetic mean particle diameter X of the porous resin particle 30 when it is being shown typically is shown. FIG. 2A shows the case where X / T is less than 0.5, FIG. 2B shows the case where X / T is 0.5 to 3.0, and FIG. FIG. 6 shows a schematic cross section near the surface of the developing roller when / T is greater than 3.0. FIG. 3A shows a schematic diagram of a cross section in the vicinity of the developing roller surface when X is less than 5 μm, and FIG. 3B shows a case where X is greater than 50 μm. In addition, T is the thickness of the surface layer 3 in the part without the convex part by the porous resin particle 30 as shown in FIG.

  When X / T <0.5 as shown in FIG. 2A or when X <5 μm as shown in FIG. 3A, the surface layer 3 and the developer regulating member 9 The gap becomes smaller. As a result, the number of frictions with the developer regulating member 9 per unit mass of the developer 8 increases, and the deterioration of the developer 8 is accelerated. Further, when X / T> 3.0 as shown in FIG. 2C or when X> 50 μm as shown in FIG. 3B, the surface layer 3 and the developer regulating member 9 The gap becomes larger. As a result, there is a developer 31 (developer indicated by hatching in the drawing) that stays without moving even when rubbed with the developer regulating member 9.

  That is, if the gap between the surface layer 3 and the developer regulating member 9 is small, the deterioration of the developer 30 is accelerated, and if the gap between the surface layer 3 and the developer regulating member 9 is large, the developer regulating member 9 is rubbed. However, the developer 31 stays without moving.

  That is, it is preferable to form an appropriate gap between the surface layer 3 and the developer regulating member 9 as shown in FIG. That is, it is preferable to satisfy the following two expressions.

0.5 ≦ X / T ≦ 3.0,
5 μm ≦ X ≦ 50 μm.

  In particular, it is preferable to satisfy the following two expressions.

0.5 ≦ X / T ≦ 2.0,
5 μm ≦ X ≦ 20 μm.

  However, only by appropriately adjusting the gap between the surface layer and the developer regulating member described above, the fusion of the developer in the latter half of the durability cannot be sufficiently prevented. Therefore, it is possible to prevent fusion by improving the releasability of the place where the developer tends to stay. That is, when the porous resin particles dispersed on the surface of the developing roller contain the non-reactive fluorine compound / silicone compound, the releasability of the convex portion on the surface of the developing roller can be improved. In the present invention, the use of porous resin particles can increase the total amount of non-reactive fluorine compound / silicone compound present on the convex portion of the developing roller surface as compared with the case of using nonporous resin particles. it can. In addition, since the porous resin particles contain the non-reactive fluorine compound / silicone compound, the total amount of the non-reactive fluorine compound / silicone compound contained in the developing roller can be reduced, and to other members such as a photosensitive drum. The pollution of the can also be reduced.

  Next, the fusing property of the developer with respect to the compressive strength A of the porous resin particles will be described. In the present invention, porous resin particles having moderate hardness, that is, porous resin particles having a compressive strength A of 1.0 MPa ≦ A ≦ 5.0 MPa, particularly 2.0 MPa ≦ A ≦ 4.0 MPa are used. Thus, a developing roller having a desired image density and releasability can be obtained. That is, when the compressive strength of the porous resin particles is within the above numerical range, the particles are appropriately deformed, and the releasability is sufficiently exhibited by the exudation of the non-reactive fluorine compound / silicone compound. Further, since the deformation of the porous resin particles is not too large, a desired image density can be obtained.

  Further, in the present invention, when the film thickness T of the surface layer and the MD-1 hardness M of the surface layer satisfy 2 μm ≦ T ≦ 25 μm and 30 degrees ≦ M ≦ 43 degrees, further suppression of fogging, image density A further improvement is achieved. When T and M satisfy the above numerical range, the hardness of the developing roller does not increase too much. Therefore, the developer is hardly deteriorated and fogging is suppressed. Moreover, since the strength of the surface layer is sufficient, excessive wear of the surface layer of the developing roller can be suppressed during durable printing. Furthermore, since the tack of the developing roller does not become too large, the developer is prevented from sticking to the surface of the developing roller from the beginning. More preferable numerical ranges of T and M are as follows.

5 μm ≦ T ≦ 20 μm,
32 degrees ≦ M ≦ 40 degrees.

In the present invention, the specific surface area of the porous resin particles is ² to 100 m ² / g. When the specific surface area of the porous resin particles is within the above numerical range, the non-reactive fluorine compound / silicone compound does not exude excessively, and a decrease in image density can be suppressed.

  In the developing roller according to the present invention, the conductive shaft body 1 shown in FIG. 1 is usually made of a metal made of aluminum, iron, stainless steel (SUS) and having an outer diameter of 4 to 10 mm. The shape may be columnar or cylindrical.

Next, for the elastic layer 2 provided around the conductive shaft body 1, silicone rubber, EPDM or urethane elastomer, or other resin moldings can be used as a base material. Also, an electronic conductive material such as carbon black, metal, metal oxide, or an ionic conductive material such as sodium perchlorate is blended, and the resistance region of the elastic layer is 10 ³ to 10 ¹⁰ Ωcm, preferably 10 ^4. What was adjusted so that it might become -10 < ⁸ > ohm-cm is used. At this time, it is preferable that the elastic layer has an ASKER-C hardness of 25 to 60 °.

  Specific examples of the base material of the elastic layer 2 include the following. Polyurethane, natural rubber, butyl rubber, nitrile rubber, polyisoprene rubber, polybutadiene rubber, silicone rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, chloroprene rubber, acrylic rubber, and mixtures thereof. Silicone rubber is preferably used because of its unique properties of low hardness and high impact resilience.

  As the binder resin for the surface layer 3 formed on the outer periphery of the elastic layer 2, it is necessary to use a polyurethane resin because of the charging property and wear resistance of the developer. As the polyurethane resin of the surface layer 3, a polyether polyurethane resin is preferable. The polyether polyurethane resin can reduce the hardness of the coating and has high developer chargeability.

  The polyether polyurethane resin can be obtained by a reaction between a known polyether polyol and an isocyanate compound. Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. These polyol components may be prepolymers that are chain-extended with an isocyanate such as 2,4-tolylene diisocyanate (TDI), 1,4-diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), if necessary. .

  Specific examples of the isocyanate compound to be reacted with these polyol components include the following. Aliphatic polyisocyanates such as ethylene diisocyanate, aliphatic polyisocyanates such as 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), cyclohexane 1,3-diisocyanate, cyclohexane 1,4-diisocyanate, 2,4 -Tolylene diisocyanate, aromatic polyisocyanate of 2,6-tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), modified products and copolymers thereof, and block bodies thereof.

  In the present invention, the desired image density can be obtained by changing the content of the porous resin particles dispersed in the surface layer 3 from 10 parts by mass to 80 parts by mass with respect to 100 parts by mass of the polyurethane resin. Therefore, it is preferable. This is because the developer transportability is improved by setting the roughness of the developing roller surface to an appropriate value.

<Non-reactive fluorine compound, non-reactive silicone compound>
The non-reactive fluorine compound and the non-reactive silicone compound are hydrogen that reacts with an isocyanate group such as active hydrogen (hydrogen of a hydroxyl group or hydrogen of an amino group), a reactive double bond such as a vinyl group, an epoxy group, It is a compound that does not have a carboxyl group. When it has a reactive functional group, it is incorporated as a part of the polyurethane resin, and the molecular mobility is greatly reduced, so that the effect of the present invention is difficult to express specifically.

<< Non-reactive fluorine compound >>
Examples of the non-reactive fluorine compound in the present invention include oligomer or polymer fluorine compounds which are liquid at a temperature of 23 ° C. In particular, perfluoropolyether is preferred. Furthermore, a perfluoropolyether containing a perfluorooxypropylene unit represented by the following formula (1) is more preferable.

<< Non-reactive silicone compound >>
Non-reactive silicone compounds in the present invention include ether-modified, alkyl-modified, and fluorine-modified compounds that are liquid at a temperature of 23 ° C. Of these, ether-modified ones are preferable, and polyoxyethylene-modified silicone compounds are more preferable. The form of copolymerization of the silicone part and the polyoxyethylene part may be any of a linear block polymer type, a branched block polymer type, and a graft polymer type of the silicone part and the polyoxyethylene part. Preferred are non-reactive silicone compounds represented by the following general formulas (a) to (d). The ether group has the highest occupied molecular orbital electron cloud which is electron donating, and therefore, the triboelectric charging ability to the developer is large, and the decrease in the charge amount of the developer can be reduced. In order to make the concentration of the ether group relatively high, perfluoropolyether or oxyalkylene having a small number of carbon atoms is preferable.

(In formula (1), n represents a positive integer.)

(In formulas (a) to (d), m and n each represent a positive integer.)
On the other hand, the weight average molecular weight (Mw) of the non-reactive fluorine compound and the non-reactive silicone compound is preferably in the range of 5600 ≦ Mw ≦ 11000. When the weight average molecular weight is within the above range, it shows an appropriate content and an appropriate exuding property from the porous resin particles, and a non-reactive fluorine compound / silicone compound in the vicinity of the porous resin particles on the surface of the developing roller. Is more likely to exist.

  The molecular structures of non-reactive fluorine compounds and non-reactive silicone compounds are isolated from porous resin particles by appropriate means and identified by using methods such as pyrolysis GC / MS, NMR, IR, and elemental analysis. can do. The weight average molecular weight can be measured by gel permeation chromatography (GPC).

  Specific examples of the porous resin particles contained in the surface layer 3 include the following. Acrylic resin, urethane resin, silicone resin, amino resin, polyester resin, polyamide resin, polycarbonate resin, epoxy resin, etc. An acrylic resin is preferably used from the viewpoint of dispersibility and uniformity of particle diameter. In addition, from the viewpoint of improving fog as described above, the above conditions must be satisfied in terms of the specific surface area, arithmetic mean particle size X, and compressive strength A of the porous resin particles. As long as such characteristics are satisfied, the porous resin particles contained may be single or plural types. Further, in order to control the arithmetic average particle diameter X of the porous resin particles, the porous resin particles may be classified. The classification device is not particularly limited, and a normal classification device such as a sieving machine, a gravity classifier, a centrifugal classifier, or an inertia classifier can be used. It is preferable to use an air classifier such as a gravity classifier, a centrifugal classifier, or an inertia classifier because the productivity is good and the classification point can be easily changed.

  The method for including the non-reactive fluorine compound / silicone compound in the porous resin particles is not particularly limited. A preferable method includes a method in which the porous resin particles and the non-reactive fluorine compound / silicone compound are stirred and impregnated under reduced pressure. Specifically, after the porous resin particles are put into an openable / closable vacuum chamber in which the internal atmospheric pressure can be adjusted, the pressure in the vacuum chamber is reduced to 200 mmHg or less to remove the air in the porous resin particles. Thereafter, non-reactive fluorine compound / silicone compound is injected, the inside of the vacuum chamber is pressurized by about 200 to 300 mmHg, and the non-reactive fluorine compound / silicone compound is forcibly impregnated into the porous resin particles. After stirring for about 60 minutes, the pressure in the vacuum chamber is returned to atmospheric pressure. In addition, when mixing a non-reactive fluorine compound / silicone compound in a vacuum chamber, you may heat as needed in order to reduce the viscosity of a non-reactive fluorine compound / silicone compound. The porous resin particles are preferably immersed in a non-reactive fluorine compound / silicone compound in a vacuum chamber.

  The content of the non-reactive fluorine compound / silicone compound with respect to the porous resin particles is preferably 10 parts by mass to 80 parts by mass, and 30 parts by mass to 80 parts by mass with respect to 100 parts by mass of the porous resin particles. More preferably, it is a part. When the content of the non-reactive fluorine compound / silicone compound is within the above numerical range, the effects of the present invention are sufficiently obtained. The following formula was used to calculate the content of the non-reactive fluorine compound / silicone compound.

α = 100 × (β−γ) / γ
Here, the content of the non-reactive fluorine compound / silicone compound is α (parts by mass). Also, the weight of the porous resin particles before containing the non-reactive fluorine compound / silicone compound is γ (g), and the weight of the porous resin particles after containing the non-reactive fluorine compound / silicone compound is β (g ).

  The developing roller of the present invention can be obtained by forming the elastic layer 2 around the conductive shaft 1 using a known method and forming the surface layer 3 on the outer periphery thereof by a known method. Here, the method for forming the elastic layer 2 is not particularly limited, but since the elastic layer 2 can be formed with high dimensional accuracy, a method for forming the elastic layer 2 by injecting an elastic material into the mold is preferable. .

  Further, the method of forming the surface layer 3 is not particularly limited, but a method of coating the surface layer paint on the elastic layer 2 is preferable because a stable surface shape can be obtained. In particular, dip coating that overflows the coating from the upper end of the immersion tank as described in JP-A-57-5047 is preferable because of excellent production stability. FIG. 6 is a schematic view of an overflow type dip coating apparatus. The cylindrical immersion tank 25 has an inner diameter larger than the outer shape of the conductive shaft body 1 on which the elastic layer 2 is formed, and has a depth larger than the axial length of the conductive shaft body 1 on which the elastic layer 2 is formed. Have An annular liquid receiving portion is provided on the outer periphery of the upper edge of the immersion tank 25 and is connected to the stirring tank 27. The bottom of the immersion tank 25 is connected to the stirring tank 27, and the paint in the stirring tank 27 is sent to the bottom of the immersion tank 25 by the liquid feed pump 26. The paint sent to the bottom of the immersion tank 25 overflows from the upper end of the immersion tank 25 and returns to the agitation tank 27 through the liquid receiving portion on the outer periphery of the upper edge of the immersion tank 25. The roller provided with the elastic layer 2 on the conductive shaft 1 is fixed vertically to the elevating device 28, immersed in the immersion tank 25, and pulled up to form the surface layer 3.

  Specific examples of the conductive material used for adjusting the electric resistance of the elastic layer 2 and the surface layer 3 in the present invention include the following. “Ketjen Black EC” (trade name, manufactured by Ketjen Black International Co., Ltd.), conductive carbon of acetylene black, carbon for rubber of SAF, ISAF, HAF, FEF, GPF, SRF, FT, MT, oxidation treatment Carbon (copper), silver, germanium metals and metal oxides, ion conductive materials, etc. for which color is applied. Among these, carbon black is preferable because the conductivity can be controlled with a small amount. These conductive materials are preferably 0.5 to 50 parts by mass, more preferably 1 to 30 parts by mass with respect to 100 parts by mass of the base material of the elastic layer 2 or the surface layer 3. Moreover, the following are mentioned as an ion conductive substance used as a conductive material. Organic ionic conductive materials such as sodium perchlorate, lithium perchlorate, calcium perchlorate, inorganic ionic conductive materials such as lithium chloride, modified aliphatic dimethyl ammonium etosulphate and stearyl ammonium acetate. These conductive materials can be used alone or in combination of two or more.

  In the present invention, the method for dispersing the conductive substance in the material forming the elastic layer 2 is not particularly limited, and it is dispersed using a known apparatus such as a roll, a Banbury mixer, a pressure kneader or the like. Can do.

  Further, the method for dispersing the conductive substance and the porous resin particles in the coating material forming the surface layer 3 is not particularly limited. For example, the conductive substance or the porous resin particles are added to a resin solution obtained by dissolving a resin material containing a polyurethane resin in an appropriate organic solvent, and a known apparatus such as a sand grinder, a sand mill, or a ball mill is used. Can be dispersed.

The electric resistance of the developing roller of the present invention is preferably 1 × 10 ⁵ Ω or more and 1 × 10 ⁷ Ω or less. That is, even when used in a process in which a bias is applied to the developing blade, the occurrence of blade bias leakage and the development negative ghost can be suppressed.

  The electrophotographic process cartridge of the present invention includes the developing roller according to the present invention and a developer regulating member in contact with the developing roller. By using the developing roller of the present invention, the fog can be improved in any toner, but since a higher fog improving effect is obtained, the weight average particle diameter of the toner particles in the toner is increased. It is preferable that they are 4 micrometers or more and 8 micrometers or less.

  The toner particles that can be used in the present invention can be produced, for example, by the following method, but are not limited to the following method.

Toner particles are directly applied using suspension polymerization methods described in JP-B-36-10231, JP-A-59-53856, JP-A-59-61842, JP-A-2006-106198, and the like. How to generate;
An emulsion polymerization method represented by a soap-free polymerization method in which toner particles are directly polymerized in the presence of a soluble and water-soluble polymerization initiator in the monomer;
Interfacial polymerization method such as microcapsule production method, in situ polymerization method; coacervation method;
A method by an associative polymerization method in which at least one kind of fine particles are aggregated as disclosed in JP-A Nos. 62-106473 and 63-186253;
A method by a dispersion polymerization method characterized by monodispersion; a method by an emulsion dispersion method in which toner particles are obtained in water after dissolving necessary resins in a water-insoluble organic solvent;
The components for forming the toner particles are kneaded and dispersed uniformly using a pressure kneader, extruder or media disperser, then cooled, and the kneaded product is allowed to collide with the target under a mechanical or jet stream, as desired. A pulverization method in which the toner particles are finely pulverized to a toner particle size and further subjected to a classification step to sharpen the particle size distribution to produce toner particles;
A method of obtaining toner particles by subjecting toner particles obtained by a pulverization method to spheronization treatment by heating or the like in a solvent.

  Among them, the production of toner particles by suspension polymerization, association polymerization, or emulsion dispersion is preferred, and suspension polymerization is preferred because toner particles having a small particle diameter can be easily obtained.

  Further, the shape of the toner particles is preferably close to a sphere, and specifically, the arithmetic average circularity of the toner particles is preferably 0.970 to 0.990. The arithmetic average circularity is an index indicating the degree of unevenness of the toner particles, and is 1.000 when the toner particles are completely spherical. The more complicated the surface shape, the smaller the arithmetic average circularity is. Become.

  FIG. 5 is a schematic view of an example of an electrophotographic process cartridge using the developing roller of the present invention. The electrophotographic process cartridge 4 in FIG. 5 includes a developing device 10 including a developing roller 6, a developer applying member 7, a developer 8, and a developer regulating member 9 to which a blade bias can be applied, a photosensitive drum 5, a cleaning blade 14, and waste development. An agent container 13 and a charging device 12 are provided.

  The photosensitive drum 5 rotates in the direction of the arrow, is uniformly charged by a charging member 12 for charging the photosensitive drum 5, and the surface thereof is exposed by laser light 11 which is an exposure means for writing an electrostatic latent image on the photosensitive drum 5. An electrostatic latent image is formed. The electrostatic latent image is developed by applying the developer 8 by the developing device 10 disposed in contact with the photosensitive drum 5 and visualized as a developer image.

  The developing device 10 includes a developing container that stores the developer 8 as a one-component developer, and a book as a developer carrying member that is located in an opening extending in the longitudinal direction in the developing container and is opposed to the photosensitive drum 5. And a developing roller 6 according to the invention. The developing device 10 develops and visualizes the electrostatic latent image on the photosensitive drum 5.

  The development process using the electrophotographic process cartridge 4 will be described in detail below. A developer 8 is applied onto the developing roller 6 by a developer application member 7 that is rotatably supported. The developer 8 applied on the developing roller 6 is rubbed against the developer regulating member 9 by the rotation of the developing roller 6. Here, the developer 8 on the developing roller 6 is uniformly coated on the developing roller 6 by the bias applied to the developer regulating member 9, and a thin layer of the developer 8 is formed on the surface of the developing roller 6. . The developing roller 6 contacts the photosensitive drum 5 while rotating, and a toner image is formed by developing the electrostatic latent image formed on the surface of the photosensitive drum 5 with the developer 8 coated on the developing roller 6. . Here, the polarity of the bias applied to the developer regulating member 9 is the same as the charging polarity of the developer 8, and the voltage is generally several tens to several hundreds V higher than the development bias. is there. Thus, when applying a bias to the developer regulating member 9, the developer regulating member 9 is preferably conductive, and more preferably a metal such as phosphor bronze or stainless steel.

  The developer application member 7 has a foamed skeleton-like sponge structure or a fur brush structure in which fibers such as rayon and polyamide are planted on the shaft core, and the developer 8 is supplied to the developing roller 6 and undeveloped. It is preferable from the viewpoint of stripping off the developer. For example, an elastic roller in which polyurethane foam is provided on the shaft core can be used.

  The contact width of the developer application member 7 with respect to the developing roller 6 is preferably 1 to 8 mm, and it is preferable that the developing roller 6 has a relative speed at the contact portion.

  FIG. 4 is a cross-sectional view showing a schematic configuration of an example of an image forming apparatus according to the present invention using an electrophotographic process cartridge equipped with the developing roller of the present invention. As the electrophotographic process cartridge, an electrophotographic process cartridge similar to the electrophotographic process cartridge 4 shown in FIG. 5 is detachably mounted.

  Development is performed by so-called reversal development in which a developer image is formed on the exposed portion. The paper 22 as a recording medium is supplied to the transfer conveyance belt 20 by a paper feed roller 23 and a suction roller 24. The bias power source 18 is a power source that applies a bias to the suction roller 24. The transfer conveyance belt 20 is stretched between the driving roller 16, the tension roller 19, and the driven roller 21, and is rotated by the driving roller 16. The developer image visualized by the above method on the photosensitive drum 5 is transferred onto a paper 22 as a recording medium by a transfer roller 17 as a transfer member. The paper 22 to which the developer image has been transferred is fixed by the fixing device 15 and discharged outside the device, thus completing the printing operation.

  On the other hand, the untransferred developer remaining on the photosensitive drum 5 without being transferred is scraped off by a cleaning blade 14 for cleaning the surface of the photosensitive drum 5 and stored in a waste developer container 13. Repeat the operation.

  Each physical property is measured by the following measuring method.

<Method for measuring specific surface area of porous resin particles>
The specific surface area is measured by using a specific surface area meter (trade name: “Autosorb-1”, manufactured by QUANTACHROME) according to the method for measuring the specific surface area of JIS Z8830. The measurement sample is about 0.1 g, weighed in a cell, and degassed for 12 hours or more at a temperature of 40 ° C. and a vacuum degree of 1.0 × 10 ⁻³ mmHg. Thereafter, nitrogen gas is adsorbed while being cooled with liquid nitrogen, and a value is obtained by a multipoint method.

<Measuring method of arithmetic average particle diameter X of porous resin particles>
The arithmetic average particle size X of the porous resin particles is an arithmetic average value of the maximum diameters of the respective porous resin particles measured by randomly selecting 200 particles. For the measurement of the maximum diameter, FE-SEM (trade name: “S-4800”) manufactured by Hitachi High-Technology Corporation is used for observation and measurement.

<Measurement method of compressive strength A of porous resin particles>
The compression hardness A of the porous resin particles is measured as follows. The measurement environment is an environment of a temperature of 23 ° C. and a relative humidity of 55%, and the porous resin particles are left in the environment for 24 hours before the measurement. The particle diameter d (mm) of the porous resin particles is measured with a digital microscope attached to an ultra-micro hardness measuring device (trade name: “ENT-2100”, manufactured by Elionix Co., Ltd.). Next, a 20 μm square planar indenter is attached to the ultra-micro hardness measuring device, and a 1 mN load is added every second, and the particle diameter in the applied direction is the particle diameter d (mm before applying the load). ) Until it reaches 90%. The load P (N) applied to the flat indenter when the particle diameter of the porous resin particles is compressed to 90% is measured. The load P (N) applied to the planar indenter is substituted into the following formula and defined as the compressive strength A (MPa) of the porous resin particles.

E = 2.8P / πd ² (MPa)
<Measurement method of film thickness T of developing roller surface layer>
The developing roller is left in an environment of a temperature of 23 ° C./humidity of 55% Rh for 24 hours or more. Using a sharp razor blade, the surface layer of the developing roller is cut out into a semi-cylindrical shape together with the elastic layer from a total of three points 30 mm from the center of the developing roller and both ends of the developing roller. (1) to (3) are obtained. In each of the obtained samples (1) to (3), the measurement position was changed to measure the 5-point surface layer thickness, and the arithmetic average value of the measurement results of 15 points in total was used as the film thickness T of the surface layer of the developing roller. (Μm). Here, as a means for measuring the film thickness T of the surface layer, a video microscope (manufactured by Keyence Corporation, magnification 2000 times) is used.

<Method for Measuring MD-1 Hardness M of Surface Layer of Developing Roller>
The developing roller is left in an environment of a temperature of 23 ° C./humidity of 55% Rh for 24 hours or more. The surface hardness of the developing roller is measured using a micro rubber hardness meter MD-1 type A (manufactured by Kobunshi Keiki Co., Ltd.). The measurement position is measured in the axial direction of the developing roller for 3 points in the axial center and 30 mm inward from both ends in the axial direction, with a total of 12 points in 90 ° increments in the circumferential direction, and the average value is developed. The MD-1 hardness M (degree) of the surface layer of the roller.

<Measurement method of weight average molecular weight (Mw) of non-reactive fluorine compound or non-reactive silicone compound>
In the present invention, the weight average molecular weight (Mw) is measured using a method for measuring molecular weight distribution by gel permeation chromatography (GPC).

The weight average molecular weight (Mw) of the chromatogram by GPC is measured under the following conditions. The column is stabilized in a heat chamber at a temperature of 40 ° C., and tetrahydrofuran (THF) is allowed to flow through the column at this temperature as a solvent at a flow rate of 1 ml per minute. About 100 μl of a THF sample solution of a non-reactive fluorine compound or a non-reactive silicone compound adjusted to a sample concentration of 0.3% by mass is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts (retention time). As standard polystyrene samples for preparing calibration curves, the molecular weights are 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ^5. 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ are used. Suitably at least 10 standard polystyrene samples are used. These are manufactured by Tosoh Corporation, Pressure Chemical Co. It is sold by the company. An RI (refractive index) detector is used as the detector.

  As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns, and use a combination of “shodex GPC KF-801, 802, 803, 804, 805, 806, 807” (trade name) manufactured by Showa Denko K.K. Can do. Moreover, a combination of “μ-styragel 500, 103, 104, 105” (trade name) manufactured by Waters Corporation can be given.

<Method for measuring electrical resistance of developing roller>
As an electrical resistance measuring apparatus, an apparatus as shown in FIG. 7 is used in an environment of a temperature of 23 ° C./humidity of 55% Rh. The developing roller 6 is in contact with a metal drum 29 having a diameter of 50 mm with a load of 4.9 N applied to both ends of the conductive shaft of the developing roller 6, and the surface speed of the metal drum 29 is driven by driving means (not shown). By driving at 50 mm / sec, the developing roller 6 is driven to rotate. A voltage of +50 V is applied to the conductive shaft of the developing roller 6 from the high voltage power supply HV. A digital multimeter DMM is used to measure the potential difference between both ends of a resistor R having a known electrical resistance (two or more digits lower than the electrical resistance of the developing roller 6) disposed between the metal drum 29 and the ground. Use to measure. As the DMM, “189TRUE RMS MULTITIMER” (trade name, manufactured by FLUKE) is used. From the measured potential difference and the electrical resistance of the resistor, the current flowing through the metal drum 29 via the developing roller 6 is calculated. The electric resistance value of the developing roller 6 is obtained from the current and the applied voltage. Here, in the measurement with the digital multimeter DMM, sampling is performed for 3 seconds after 2 seconds of voltage application, and the value calculated from the average value is set as the resistance value of the developing roller 6.

<Method of measuring weight average particle diameter of toner particles>
The weight average particle diameter of the toner particles can be measured by “Coulter Counter TA-II Type” or “Coulter Multisizer” (trade name, manufactured by Coulter). Specifically, it can be measured as follows. Using “Coulter Multisizer” (trade name, manufactured by Beckman Coulter, Inc.), an interface for outputting a volume distribution (manufactured by Nikka) and a “PC9801 personal computer” (trade name, manufactured by NEC) are connected. As the electrolytic solution, a 1% NaCl aqueous solution prepared using primary sodium chloride can be used. For example, “ISOTON R-II” (trade name, manufactured by Coulter Scientific Japan Co., Ltd.) can be used. The specific measurement procedure is as follows. 100 to 150 ml of the electrolytic aqueous solution is added, and 2 to 20 mg of a measurement sample (toner particles) is further added. The electrolytic solution in which the sample is suspended is dispersed for about 1 to 3 minutes with an ultrasonic disperser, and the volume distribution is calculated by measuring the volume of toner particles of 2 μm or more using the “Coulter Multisizer” with a 100 μm aperture. To do. From this, the weight average particle diameter is determined.

<Method for measuring arithmetic average circularity of toner particles>
Using a flow type particle image measuring device “FPIA-2100 type” (trade name: manufactured by Sysmex Corporation), 1000 or more toner particles were measured, and the circularity a of each measured particle was determined by the following equation: The arithmetic average is defined as the arithmetic average circularity.

Circularity a = L0 / L
(In the formula, L0 represents the circumference of a circle having the same projected area as the particle image, and L represents the particle image when image processing is performed with an image processing resolution of 512 × 512 (pixels of 0.3 μm × 0.3 μm). Indicates the perimeter).

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example and a comparative example, a present Example does not limit this invention at all.

[Example 1]
[Formation of Elastic Layer 2]
As the conductive shaft 1, an SUS 8 mm diameter metal core was subjected to nickel plating, and a primer (trade name: “DY35-051”, manufactured by Toray Dow Corning Silicone) was applied and baked. Next, the conductive shaft 1 was arranged concentrically with a cylindrical mold having an inner diameter of 16 mm. The following materials were mixed with 100 parts by mass of a liquid silicone rubber material (trade name: “SE6724A / B”, manufactured by Toray Dow Corning Silicone Co., Ltd.) to prepare an addition type silicone rubber composition. 35 parts by mass of carbon black (trade name: “Toka Black # 7360SB”, manufactured by Tokai Carbon Co., Ltd.), 0.2 parts by mass of silica powder as a heat resistance imparting agent, and 0.1 parts by mass of platinum catalyst. The addition type silicone rubber composition was injected into a cavity formed in the mold. Subsequently, the mold was heated to cure and cure the silicone rubber composition at a temperature of 150 ° C. for 15 minutes, and after demolding, it was further heated at a temperature of 200 ° C. for 2 hours to complete the curing reaction. 2 was provided on the outer periphery of the conductive shaft body 1.

[Synthesis of polyether polyol]
Polytetramethylene glycol (trade name: “PTG1000SN”, manufactured by Hodogaya Chemical Co., Ltd.) 100 parts by mass, and isocyanate compound (trade name: “Millionate MT”, manufactured by Nippon Polyurethane Industry Co., Ltd.) 20 parts by mass in a methyl ethyl ketone (MEK) solvent. And stepwise mixed. A polyether polyol having a hydroxyl value of 20 was prepared by reacting at a temperature of 80 ° C. for 7 hours under a nitrogen atmosphere.

[Synthesis of Block Polyisocyanate A]
Under a nitrogen atmosphere, 57 parts by mass of crude MDI was heated at 90 ° C. for 2 hours with respect to 100 parts by mass of polypropylene glycol having a number average molecular weight of 500. Thereafter, butyl cellosolve was added so as to have a solid content of 70%, and an isocyanate compound having a mass ratio of NCO groups contained per unit solid mass of 5.0% by mass was obtained. Thereafter, 22 parts by mass of MEK oxime was added dropwise under a reaction temperature of 50 ° C. to obtain block polyisocyanate A.

[Method of synthesizing porous resin particles]
“Preparation of porous resin particles 1”
(Oil layer material)
N-butyl acrylate 30 parts by mass diethylene glycol dimethacrylate 20 parts by mass n-hexane 50 parts by mass benzoyl peroxide 0.3 parts by mass (water layer material)
Ion-exchanged water 350 parts by mass Calcium phosphate 6 parts by mass Sodium lauryl sulfate 0.03 parts by mass The above oil layer material and water layer material were mixed, and this mixed solution was mixed with a high-speed stirrer (trade name: “TK homomixer”, special machine Using a chemical industry), stirring and granulation were performed at a stirring rotational speed of 4000 rpm for 10 minutes. Thereafter, the temperature was raised to 65 ° C. while stirring with a paddle stirring blade, and suspension polymerization was performed for 7 hours. After completion of the polymerization, the suspension was cooled to a temperature of 23 ° C., hydrochloric acid was added to dissolve the calcium phosphate as a dispersant, filtered, washed with water, and dried to prepare porous resin particles 1.

“Preparation of porous resin particles 2-8”
Porous resin particles 2 to 8 were produced in the same manner as in the production of the porous resin particles 1 except that the materials and the stirring rotation speed of the high-speed stirrer were set to the conditions shown in Table 1.

“Preparation of porous resin particles 9”
Polyamide 6 (molecular weight 1300, manufactured by Ube Industries) was dissolved in an m-cresol solution to prepare a polyamide solution having a concentration of 1.0% by mass. Next, 12.5 parts by mass of the polyamide solution was added to a mixed solution of 75 parts by mass of methanol and 12.5 parts by mass of water, and the mixture was added while stirring with a magnetic stirrer. Thereafter, the mixture was stirred at a temperature of 23 ° C. for 2 minutes. After stirring, the mixture was allowed to stand at a temperature of 23 ° C. for 24 hours to precipitate polyamide particles. By filtering and washing the particles, porous resin particles 9 were produced.

“Preparation of porous resin particles 10 and 12 to 15”
In the production of the porous resin particles 1, porous resin particles 10 and 12 to 15 were produced in the same manner except that the materials and the stirring rotation speed of the high-speed stirrer were set as shown in Table 1.

“Preparation of porous resin particles 11”
Porous resin particles 11 were produced in the same manner as in the production of the porous resin particles 1 except that the materials and the stirring rotation speed of the high-speed stirrer were changed to the conditions shown in Table 1.

[Non-reactive fluorine compound]
As the non-reactive fluorine compound A, “DEMNUM S-200” (trade name, manufactured by Daikin Industries, Ltd.) was used. As the non-reactive fluorine compound B, “DEMNUM S-100” (trade name, manufactured by Daikin Industries, Ltd.) was used. Further, “DEMNUM S-20” (trade name, manufactured by Daikin Industries, Ltd.) was used as the non-reactive fluorine compound C. Table 2 shows the weight average molecular weights Mw of the non-reactive fluorine compounds A to C.

[Method of synthesizing non-reactive silicone compound]
"Synthesis of non-reactive silicone compound A"
10 g of polypropylene glycol monobutyl ether (Mn = 1000, manufactured by Aldrich) and Jones reagent were reacted in acetone at a temperature of 20 ° C. for 24 hours to obtain a polyether part raw material. The Jones reagent was prepared by adding 0.011 mol of concentrated sulfuric acid to a solution of 0.007 mol of chromium (VI) oxide in 1 ml of water while cooling with ice, and then adding 2 ml of water. 5.0 g of this raw material and 0.095 mol of oxalyl dichloride (manufactured by Aldrich) were reacted in benzene at a temperature of 40 ° C. for 5 hours to obtain an acid chloride. 2.5 g of the obtained acid chloride and 5.0 g of a polysiloxane compound (trade name: “KF6002”, manufactured by Shin-Etsu Chemical Co., Ltd.) were reacted in diethyl ether in the presence of a small amount of pyridine at room temperature for 24 hours. A non-reactive silicone compound A having an average molecular weight of 7900 was obtained.

"Synthesis of non-reactive silicone compound B"
Polypropylene glycol monobutyl ether (Mn = 2500, manufactured by Aldrich) and Jones reagent were reacted in acetone at a temperature of 20 ° C. for 24 hours to obtain a polyether part raw material. The Jones reagent was prepared by adding 0.005 mol of concentrated sulfuric acid to 1 ml of water containing 0.003 mol of chromium (VI) oxide while cooling with ice, and then adding 2 ml of water. 5.0 g of this raw material and 0.05 mol of oxalyl dichloride (manufactured by Aldrich) were reacted in benzene at a temperature of 40 ° C. for 5 hours to obtain an acid chloride. 2.5 g of the obtained acid chloride and 3.0 g of a polysiloxane compound (trade name: “KF6002”, manufactured by Shin-Etsu Chemical Co., Ltd.) were reacted in diethyl ether in the presence of a small amount of pyridine at room temperature for 24 hours. A non-reactive silicone compound B having an average molecule of 11000 was obtained.

"Synthesis of non-reactive silicone compound C"
10 g of polyethylene glycol monomethyl ether (Mn = 550, manufactured by Aldrich) and Jones reagent were reacted in acetone at a temperature of 20 ° C. for 24 hours to obtain a polyether part raw material. The Jones reagent was prepared by adding 0.022 mol of concentrated sulfuric acid to a 2 ml solution of 0.014 mol of chromium (VI) oxide in water while cooling with ice, and then adding 4 ml of water. 5.0 g of this raw material and 0.014 mol of oxalyl dichloride (manufactured by Aldrich) were reacted in benzene at a temperature of 40 ° C. for 5 hours to obtain an acid chloride. 2.5 g of the obtained acid chloride and 27.5 g of a polysiloxane compound (trade name, “X22-170DX”, manufactured by Shin-Etsu Chemical Co., Ltd.) were reacted in diethyl ether in the presence of a small amount of pyridine at room temperature for 24 hours. A non-reactive silicone compound C having a weight average molecular weight of 5800 was obtained.

"Synthesis of non-reactive silicone compound D"
10 g of polyethylene glycol monomethyl ether (Mn = 550, manufactured by Aldrich) and Jones reagent were reacted in acetone at a temperature of 20 ° C. for 24 hours to obtain a polyether part raw material. The Jones reagent was prepared by adding 0.022 mol of concentrated sulfuric acid to a 2 ml solution of 0.014 mol of chromium (VI) oxide in water while cooling with ice, and then adding 4 ml of water. 5.0 g of this raw material and 0.014 mol of oxalyl dichloride (manufactured by Aldrich) were reacted in benzene at a temperature of 40 ° C. for 5 hours to obtain an acid chloride. 2.5 g of the obtained acid chloride and 16 g of a polysiloxane compound (trade name, “X22-170BX”, manufactured by Shin-Etsu Chemical Co., Ltd.) were reacted in diethyl ether in the presence of a small amount of pyridine at room temperature for 24 hours. A non-reactive silicone compound D having an average molecular weight of 3700 was obtained.

"Synthesis of non-reactive silicone compound E"
Polypropylene glycol monobutyl ether (Mn = 4000, manufactured by Aldrich) and Jones reagent were reacted in acetone at a temperature of 20 ° C. for 24 hours to obtain a polyether part raw material. The Jones reagent was prepared by adding 0.003 mol of concentrated sulfuric acid to 1 ml of water containing 0.002 mol of chromium (VI) oxide while cooling with ice, and then adding 2 ml of water. 5.0 g of this raw material and 0.025 mol of oxalyl dichloride (manufactured by Aldrich) were reacted in benzene at a temperature of 40 ° C. for 5 hours to obtain an acid chloride. 2.5 g of the obtained acid chloride and 2.5 g of a polysiloxane compound (trade name: “KF6003”, manufactured by Shin-Etsu Chemical Co., Ltd.) were reacted in diethyl ether in the presence of a small amount of pyridine at room temperature for 24 hours. A non-reactive silicone compound E having an average molecular weight of 15400 was obtained. Table 2 shows the weight average molecular weights Mw of the non-reactive silicone compounds A to E.

[Method of impregnating porous resin particles with non-reactive fluorine compound / silicone compound]
After 200 g of the porous resin particles 1 were put into the vacuum chamber, the inside of the vacuum chamber was reduced to 200 mmHg and held for 1 minute. Thereafter, 400 g of a non-reactive fluorine compound was injected, and the mixture was stirred for 60 minutes with the inside of the vacuum chamber being 500 mmHg. After returning the pressure in the vacuum chamber to atmospheric pressure, the non-reactive fluorine compound not impregnated in the porous resin particles was removed. Thereafter, 280 g of porous resin particles 1 impregnated with the non-reactive fluorine compound were taken out. In addition, also when using the non-reactive silicone compound, it impregnated by the same method. Table 3 shows the content of the non-reactive fluorine compound / silicone compound with respect to 100 parts by mass of the porous resin particles.

[Preparation of paint for surface layer 3]
The block polyisocyanate A is mixed with the polyether polyol so that the NCO / OH group ratio is 1.4. Carbon black (trade name: “MA100”, Mitsubishi Chemical Co., Ltd.) with respect to 100 parts by mass of the solid content of the mixed solution. 30 parts by mass, pH = 3.5) manufactured by the company was added. Next, MEK was added and mixed so that the solid content was 35% by mass, and dispersed for 4 hours using a glass bead having a particle diameter of 1.5 mm and a sand mill to prepare dispersion 1. Thereafter, 40 parts by mass of the porous resin particles 1 were added to MEK in the same amount as the solid content in the dispersion, and ultrasonic dispersion was performed to obtain a porous resin particle dispersion. The obtained porous resin particle dispersion was added to Dispersion 1 and further dispersed for 30 minutes using a sand mill to obtain a coating for surface layer 3.

[Formation of surface layer 3 on elastic layer 2]
The coating material for the surface layer 3 obtained as described above is dip-coated on the elastic layer 2 using an overflow-type dip coating apparatus shown in FIG. The surface layer 3 having a thickness of 17 μm was provided on the surface of the elastic layer 2 by heat treatment for a period of time. As a result, the developing roller of Example 1 was obtained.

  The obtained developing roller was left in an environment of temperature 23 ° C./humidity 55% Rh for 24 hours or more, and the following various measurements were performed. In addition, as a method for taking out the porous resin particles, there is a method in which a developing roller cut with a sharp razor blade is swollen with a solvent and then subjected to ultrasonic treatment.

[Measurement of specific surface area / arithmetic mean particle diameter X / compressive strength A of porous resin particles in developing roller surface layer 3]
The specific surface area, arithmetic mean particle size X, and compressive strength A were measured from the developing roller obtained as described above by the method described above. Table 3 shows the measurement results.

[Measurement of film thickness T · MD-1 hardness M of developing roller surface layer 3]
The film thickness T · MD-1 hardness M of the surface layer of the developing roller obtained as described above was measured by the method described above. Table 3 shows the measurement results.

[Measurement of electrical resistance of developing roller]
The electric resistance of the developing roller obtained as described above was measured by the method described above. Table 3 shows the measurement results.

[Image output test]
A Canon printer “LBP5500” (trade name) modified cartridge was filled with magenta toner of non-magnetic one component. The modified cartridge has a photosensitive drum, the developing roller presses the photosensitive drum, and a blade made of SUS304 having a thickness of 80 μm is used as a developer regulating member so that a blade bias can be applied to the developer regulating member. It is a thing. The magenta toner has a weight average particle diameter of 6.5 μm, a shape factor SF-1 of 114, and SF-2 of 108 manufactured by the polymerization method described in Example 1 of JP-A-2006-106198. This is a non-magnetic one-component magenta toner. Further, three process cartridges for image output test were produced by incorporating the developing roller obtained in this example.

  The image output test cartridge was mounted on a Canon printer “LBP5500” (trade name) modified machine (modified so that a blade bias can be applied to the developer regulating member), and an image output test was performed. Here, a blade bias of −200 V is applied to the developing bias, and the temperature is 23 ° C./humidity 55% Rh (N / N environment), the temperature is 15 ° C./humidity 10% Rh (L / L environment), and the temperature is 30 ° C. An image with a printing rate of 1% was continuously output in each environment at a humidity of 80% / Rh (H / H environment). Finally, 10,000 images were output and fog was evaluated by the following method.

One solid white image was output on gloss paper (HP gloss paper). Using the reflection type densitometer “TC-6DS / A” (trade name, manufactured by Tokyo Denshoku Co., Ltd.), the solid white image was measured for the reflection density of the white background, and the average of 10 points measured on the image The value was Ds. Then, the difference (Dr−Ds) between the reflection density of the paper before outputting the solid white image (the average value is Dr) and Ds (Dr−Ds) was determined, and this was used as the fogging amount, and evaluation was performed based on the following criteria.
A: The fog amount is less than 1.5 B: The fog amount is 1.5 or more and less than 2.5 C: The fog amount is 2.5 or more.

The image density was evaluated by the following method. The developing roller was incorporated into an image output test process cartridge in the same manner as described above, and the image output test process cartridge was left in an environment of a temperature of 23 ° C. and a humidity of 55% Rh for 24 hours. Thereafter, it was mounted on the Canon “LBP5500” (trade name) remodeling machine in the same environment, and one solid black image was output. Concentration using a reflection densitometer (trade name: “RD-914”, manufactured by Macbeth Co., Ltd.) at a total of 9 points on the left, center and right of the upper, middle and lower areas of the output image. Was measured and the average value was defined as the image density. The image density was evaluated based on the following criteria.
A: Image density value is 1.1 or more B: Image density value is 1.0 or more and less than 1.1 C: Image density value is less than 1.0

  In this example, both fog and image density were good. The results are shown in Table 4.

[Examples 2 to 21]
Specific surface area / arithmetic mean particle size X / compressive strength A of porous resin particles, surface layer thickness T / MD-1 hardness M, non-reactive compound, material of porous resin particles, inclusion of porous resin particles A developing roller was produced in the same manner as in Example 1 except that the amount was changed as shown in Table 3. Various measurements and evaluations were performed in the same manner as in Example 1. In Examples 2 to 21, both fog and image density were good. The results are shown in Table 4.

[Comparative Example 1]
By using the porous resin particles 10 as the porous resin particles, the same procedure as in Example 1 was performed except that the specific surface area, arithmetic mean particle size X, and compressive strength A of the porous resin particles were changed as shown in Table 3. Thus, a developing roller was produced. Various measurements and evaluations were performed in the same manner as in Example 1. In this comparative example, the fog was good, but the image density was not sufficient as compared with the example because the specific surface area of the porous resin particles was large. The results are shown in Table 4.

[Comparative Example 2]
By using the porous resin particles 11 as the porous resin particles, the same procedure as in Example 1 was performed except that the specific surface area, arithmetic mean particle size X, and compressive strength A of the porous resin particles were changed as shown in Table 3. Thus, a developing roller was produced. Various measurements and evaluations were performed in the same manner as in Example 1. In this comparative example, since there was almost no non-reactive compound in the porous resin particles, the fog was larger than in the example. The results are shown in Table 4.

[Comparative Examples 3 to 4]
Example 1 except that the specific surface area, arithmetic mean particle size X, and compressive strength A of the porous resin particles were changed as shown in Table 3 by using the porous resin particles 12 and 13 as the porous resin particles. Similarly, a developing roller was produced. Various measurements and evaluations were performed in the same manner as in Example 1. In this comparative example, since the arithmetic average particle diameter X of the porous resin particles did not satisfy the conditions according to the present invention, the fog was larger than in the example. The results are shown in Table 4.

[Comparative Example 5]
A developing roller was produced in the same manner as in Example 1 except that the film thickness T of the surface layer was changed as shown in Table 3. Various measurements and evaluations were performed in the same manner as in Example 1. In this comparative example, since the film thickness T of the surface layer did not satisfy the conditions according to the present invention, the fog was larger than in the example. The results are shown in Table 4.

[Comparative Example 6]
Implemented except that porous resin particles 2 were used as the porous resin particles, and the specific surface area, arithmetic mean particle size X, compressive strength A, and film thickness T of the surface layer were changed as shown in Table 3. A developing roller was produced in the same manner as in Example 1. Various measurements and evaluations were performed in the same manner as in Example 1. In this comparative example, since the film thickness T of the surface layer was thin and did not satisfy the conditions according to the present invention, the surface layer was scraped with 7000 sheets of paper passing, and the fog amount could not be evaluated. The results are shown in Table 4.

[Comparative Examples 7-8]
Except that the specific surface area, the arithmetic mean particle size X, the compressive strength A, and the arithmetic mean particle size X / surface layer thickness T of the porous resin particles were changed as shown in Table 3, the same procedure as in Example 1 was performed. A developing roller was produced. Various measurements and evaluations were performed in the same manner as in Example 1. In this comparative example, since X / T did not satisfy the conditions according to the present invention, the fog was larger than in the example. The results are shown in Table 4.

[Comparative Example 9]
A developing roller was produced in the same manner as in Example 1 as shown in Table 3 except that the content of carbon black contained in the surface layer 3 was changed to 50 parts by mass. Various measurements and evaluations were performed in the same manner as in Example 1. In this comparative example, since MD-1 hardness M did not satisfy the conditions according to the present invention, the fog was larger than that in the example. The results are shown in Table 4.

[Comparative Example 10]
A developing roller was produced in the same manner as in Example 1 as shown in Table 3 except that the content of carbon black contained in the surface layer 3 was changed to 15 parts by mass. Various measurements and evaluations were performed in the same manner as in Example 1. In this comparative example, the fog was good. However, since the MD-1 hardness M is small and the conditions according to the present invention are not satisfied, initial fixation of the developer was observed. This initial sticking disappeared on the third sheet. The results are shown in Table 4.

[Comparative Example 11]
Table 3 shows the specific surface area, arithmetic mean particle size X, compressive strength A, and arithmetic mean particle size X / surface layer thickness T of the porous resin particles. A developing roller was produced in the same manner as in Example 1 except that the above was changed. Various measurements and evaluations were performed in the same manner as in Example 1. In this comparative example, since the compressive strength A of the porous resin particles did not satisfy the conditions according to the present invention, the fog was larger than in the example. The results are shown in Table 4.

[Comparative Example 12]
Table 3 shows the specific surface area, arithmetic mean particle size X, compressive strength A, and arithmetic mean particle size X / surface layer thickness T of the porous resin particles. A developing roller was produced in the same manner as in Example 1 except that the above was changed. Various measurements and evaluations were performed in the same manner as in Example 1. In this comparative example, the fog was good, but the compressive strength A of the porous resin particles was small and the conditions according to the present invention were not satisfied, so that the image density was not sufficient as compared with the example. The results are shown in Table 4.

FIG. 3 is an axial sectional view showing an example of the developing roller of the present invention. It is the schematic which showed the change of the surface profile by X / T in this invention. It is the schematic which showed the change of the surface profile by X of the porous resin particle in this invention. 1 is a schematic cross-sectional view of an image forming apparatus using a developing roller and a developing device of the present invention. 1 is a schematic cross-sectional view of an electrophotographic process cartridge using a developing roller of the present invention. It is the schematic which shows an example of the dip coating apparatus used when forming the surface layer of the developing roller of this invention. It is the schematic of the apparatus which measures the electrical resistance of the developing roller of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive shaft 2 Elastic layer 3 Surface layer 4 Electrophotographic process cartridge 5 Photosensitive drum 6 Developing roller 7 Developer application member 8 Developer 9 Developer control member 10 Developing device 11 Laser beam 12 Charging member 13 Waste developer container 14 Cleaning blade 15 Fixing device 16 Driving roller 17 Transfer roller 18 Bias power supply 19 Tension roller 20 Transfer conveyor belt 21 Drive roller 22 Paper 23 Paper feed roller 24 Adsorption roller 25 Immersion tank 26 Liquid feed pump 27 Stirring tank 28 Lifting device 29 Metal drum 30 Porous resin particle 31 staying developer R resistor HV high voltage power supply DMM digital multimeter

Claims (8)

In a developing roller having a conductive shaft, an elastic layer on the outer periphery of the conductive shaft, and a surface layer on the outer periphery of the elastic layer,
The surface layer contains a polyurethane resin and porous resin particles having a specific surface area of ² to 100 m ² / g,
The porous resin particles include at least one selected from the group consisting of a fluorine compound that is liquid and non-reactive at a temperature of 23 ° C. and a silicone compound that is liquid and non-reactive at a temperature of 23 ° C., and
The arithmetic average particle diameter X (μm) of the porous resin particles, the film thickness T (μm) of the surface layer, the MD-1 hardness M (degrees) of the surface layer, and the compressive strength A of the porous resin particles (MPa) has the following relationships (a) to (e)
(A) 0.5 ≦ X / T ≦ 3.0
(B) 5 μm ≦ X ≦ 50 μm
(C) 2 μm ≦ T ≦ 25 μm
(D) 30 degrees ≦ M ≦ 43 degrees (e) 1.0 MPa ≦ A ≦ 5.0 MPa
A developing roller characterized by satisfying   The developing roller according to claim 1, wherein the content of the porous resin particles with respect to 100 parts by mass of the polyurethane resin is 10 parts by mass to 80 parts by mass. The porous resin particles contain the fluorine compound;
The development according to claim 1 or 2, wherein the fluorine compound has a weight average molecular weight (Mw) in the range of 5600 ≦ Mw ≦ 11000, and the fluorine compound is a perfluoropolyether containing a perfluorooxypropylene unit. roller. The porous resin particles contain the silicone compound;
The developing roller according to claim 1, wherein the silicone compound has a weight average molecular weight (Mw) in the range of 5600 ≦ Mw ≦ 11000, and the silicone compound is a polyoxyethylene-modified silicone compound.   The developing roller according to claim 1, wherein the porous resin particles are formed of an acrylic resin.   The porous resin particles are prepared by stirring at least one of the fluorine compound and the silicone compound and the porous resin particles under reduced pressure so that at least one of the fluorine compound and the silicone compound is contained inside the porous resin particles. 6. The developing roller according to claim 1, wherein the developing roller is obtained by impregnation.   An electrophotographic process cartridge comprising: the developing roller according to claim 1; and a developer regulating member that is in contact with the developing roller.   An image forming apparatus comprising: the developing roller according to claim 1; and a developer regulating member that is in contact with the developing roller.

Images