JP2008262044A - Conductive roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive roller which has a conductive elastic layer and a conductive cover layer, wherein components of the conductive elastic layer does not contaminate a photoreceptor. <P>SOLUTION: The amount of the oozing components remaining in the elastic conductive layer, the crude density of the three dimensional net structure formed by the cross-linking reaction of the surface resin conductive cover layer, and the film thickness of the conductive cover layer are all specified. Thus, the remaining components in the elastic conductive layer are prevented from oozing out, contamination to the photoreceptor is prevented to obtain high resolution images and a long life conductive roller is obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a conductive roller that can be used as a developing roller, a charging roller, a transfer roller, or the like installed around a photoreceptor of an electrophotographic apparatus.

  The electrophotographic apparatus incorporates a conductive roller such as a charging roller for supplying electric charge to the photosensitive member, a developing roller for supplying toner to the photosensitive member, and a transfer roller for transferring the formed toner image onto a recording sheet. Various materials are used for these conductive rollers in order to give them characteristics suitable for the purpose. However, since these are incorporated in the periphery of the photoconductor in the electrophotographic apparatus, the photoconductor is not contaminated during use. It is required as a condition.

However, due to incomplete reaction during roller production, characteristics of the roller's constituent materials, roller usage conditions (long-term use at high temperatures), etc., the roller component completely exudes to the surface. It was difficult to prevent. For example, when silicone rubber is used as the material for the elastic layer in the conductive roller, it is often manufactured by a method in which liquid silicone rubber is poured into a mold and then heated and cured. As the liquid silicone rubber used for the casting, an addition reaction crosslinking liquid silicone rubber is often used for the following reasons.
(1) Excellent workability.
(2) There is no generation of by-products accompanying the curing reaction, and the dimensional stability is good.
(3) The physical properties after curing are stable.

  However, even when a roller is manufactured by casting an addition reaction crosslinkable liquid silicone rubber, unreacted low molecular liquid silicone rubber may remain in the conductive elastic layer depending on the manufacturing conditions. . If this low molecular liquid silicone rubber is present, it oozes out from the roller, and the low molecular siloxane contained therein contaminates the photoreceptor. The developing roller also has a problem that toner filming occurs.

  Therefore, techniques for preventing contamination of the photosensitive member by the rollers have been studied. Patent Document 1 (Japanese Patent Laid-Open No. 11-174831) discloses a technique for baking out low molecular siloxane which is an elastic layer material by heating an elastic layer constituting a roller. In patent document 1, it is supposed that the amount of n-hexane extract from the elastic layer can be reduced to 5% by mass or less.

Patent Document 2 (Japanese Patent Laid-Open No. 2000-3090) discloses a method in which a coating layer such as polyurethane is formed on the surface of an elastic layer, and the volatile component contained in the outermost coating layer is reduced to less than 200 ppm. It is used. In Patent Document 2, by using this method, the exudation component remaining in the elastic layer is blocked by the outermost coating layer and does not reach the roller surface.
JP-A-11-174831 JP 2000-3090 A

  However, in the technique of Patent Document 1, there is a limit to the heating temperature that can be used to prevent thermal deterioration of the roller, and it has been difficult to completely eliminate the low molecular siloxane residue in the elastic layer. For this reason, when the electrophotographic apparatus is used for a long period of time, the component material oozes out to the roller surface, and the image characteristics deteriorate.

  In the method of Patent Document 2, it has been difficult to completely prevent the component material from exuding to the photoreceptor depending on the amount of the exuding component in the elastic layer and the physical properties of the coating layer. Further, by increasing the thickness of the coating layer, it becomes difficult to achieve stable rotation of the roller and uniform contact with the photosensitive member, resulting in a problem that the resolution of the image and the life of the roller are reduced.

As described above, the prior art has problems in terms of increasing the resolution of images and extending the life of rollers.
Therefore, as a result of diligent study, the present inventor has obtained a high-resolution image without contaminating the photoreceptor by controlling the following characteristics in the roller within a predetermined range, and a conductive roller excellent in durability. It has been discovered that it can be provided.
(A) The amount of the exuding component remaining in the conductive elastic layer.
(B) The coarse density of the three-dimensional network structure formed by the crosslinking reaction of the conductive coating layer.
(C) Film thickness of the conductive coating layer.

The conductive roller of the present invention that solves the above problems has the following configuration.
1. A conductive roller having a conductive support, a conductive elastic layer provided on the outer periphery of the conductive support, and a conductive coating layer provided on the outer periphery of the conductive elastic layer,
The total amount of the extract when the conductive elastic layer is immersed in methyl ethyl ketone is 4% by mass or less of the mass of the conductive elastic layer before being immersed in the methyl ethyl ketone,
A conductive roller, wherein a 100% modulus of the conductive coating layer is in a range of 2 MPa or more and 10 MPa or less, and a film thickness of the conductive coating layer is 5 μm or more and 15 μm or less.

  2. 2. The conductive roller according to 1 above, wherein the conductive elastic layer contains a silicone rubber obtained by heat-curing an addition reaction cross-linkable liquid silicone rubber.

  3. 3. The conductive roller according to 1 or 2 above, wherein the conductive coating layer contains a polyurethane resin containing an isocyanate and a polyol.

  4). 4. The conductive roller according to claim 1, wherein the conductive coating layer is formed using a coating solution containing methyl ethyl ketone.

  The conductive roller of the present invention has a long life when used in an electrophotographic apparatus, and can be used for a long time. In addition, it is possible to obtain a high-resolution recorded image without causing the content components of the roller to ooze out on the surface during use and contaminating the surface of the photoreceptor that the roller contacts.

1. Conductive roller The conductive roller of the present invention includes a conductive support, a conductive elastic layer provided on the outer periphery of the conductive support, and a conductive coating layer provided on the outer periphery of the conductive elastic layer. Have The conductive roller of the present invention is characterized in the following points.
(A) When the conductive elastic layer is immersed in methyl ethyl ketone, the total amount of the extract derived from the conductive elastic layer extracted into methyl ethyl ketone is 4% by mass or less of the mass of the conductive elastic layer before being immersed in methyl ethyl ketone. Become.
(B) The 100% modulus of the conductive coating layer is in the range of 2 MPa to 10 MPa.
(C) The film thickness of the conductive coating layer is 5 μm or more and 15 μm or less.

  In the present invention, by having the configuration of the above (a), among the content components of the conductive elastic layer, the components that can penetrate into the conductive coating layer and ooze out on the surface thereof are reduced.

  In the present invention, in the above configuration (a), the total amount of the extract of the conductive elastic layer when immersed in methyl ethyl ketone is specified. This is because, when a conductive coating layer is formed using a coating solution containing methyl ethyl ketone as a solvent, some or a certain amount of methyl ethyl ketone remains in the conductive coating layer after the formation. That is, the content component of the conductive elastic layer oozes out to the surface of the conductive coating layer through the permeation into the methyl ethyl ketone. For this reason, the amount of the permeation itself can be reduced by configuring the formed conductive elastic layer from components having a small amount of extraction into methyl ethyl ketone.

  Even when a conductive coating layer is formed using a coating solution that does not contain methyl ethyl ketone as a solvent, a solvent having a structure similar to that of methyl ethyl ketone or having similar characteristics is used as the main component of the coating solution. by. That is, when a conductive coating layer is formed using a coating solution containing such a solvent, some or a certain amount of solvent remains in the conductive coating layer after the formation. As a result, the content component of the conductive elastic layer oozes out to the surface of the conductive coating layer through penetration into the solvent. Here, this solvent and methyl ethyl ketone are similar in structure or have similar characteristics. For this reason, by forming the conductive elastic layer after formation from a component having a small amount of extraction into methyl ethyl ketone, the amount of penetration into the solvent and the amount of seepage to the surface of the conductive coating layer can be reduced.

  By having the configuration of (b) above, the three-dimensional network structure formed by the crosslinking reaction of the conductive coating layer can be made dense. As a result, even if a component extracted into methyl ethyl ketone is present in the conductive elastic layer, it is difficult to penetrate the surface through the three-dimensional network structure in the conductive coating layer. As a result, the content component of the conductive elastic layer is difficult to ooze out to the surface of the conductive coating layer.

  In the present invention, the size of the 100% modulus of the conductive coating layer and the density of the three-dimensional network structure are correlated. That is, when the 100% modulus is large, the three-dimensional network structure is dense, and when the 100% modulus is small, the three-dimensional network structure is coarse. For this reason, by setting it as the range of the said structure (b), in the range which does not impair the characteristic of a conductive roller, moderate three-dimensional which inhibits the penetration | invasion into the conductive coating layer of the content component of a conductive elastic layer It can be set as the electroconductive coating layer which has a network structure.

Further, by having the configuration of (c) above, it is possible to improve the stability of the roller rotation and the contact property of the roller with the photosensitive member, to extend the life of the roller and to increase the resolution of the image. Can do.
As described above, in the conductive roller of the present invention, by having the above-described configurations (a) to (c), it is possible to prevent the content component of the conductive elastic layer from exuding to the surface of the conductive coating layer, A high-resolution image can be obtained and the life of the roller can be extended.

FIG. 1 shows a conceptual cross-sectional view of an example of the conductive roller of the present invention.
The conductive roller of the present invention comprises a conductive support 1, a conductive elastic layer 2 laminated on the conductive support 1, and a conductive coating layer 3 laminated on the conductive elastic layer 2. The conductive elastic layer 2 and the conductive coating layer 3 have conductivity, and may be a single layer or multiple layers. Further, a layer for controlling conductivity may be formed between the conductive elastic layer 2 and the conductive coating layer 3. Furthermore, an adhesive layer may be formed between each layer in order to obtain adhesion.

(Conductive support)
The conductive support 1 is not particularly limited as long as it is a core material having conductivity, and examples thereof include metals such as iron, copper, and stainless steel. In addition, the surface of these metals may be subjected to a coating process such as a plating process.

(Conductive elastic layer)
The conductive elastic layer 2 is not particularly limited as long as it has conductivity and elasticity. Preferably, it is made of silicone rubber, and a conductive agent is added inside to add conductivity. Examples of the conductive agent include a conductive agent having an electron conduction mechanism such as carbon black, graphite, and conductive metal oxide, and a conductive agent having an ion conduction mechanism such as an alkali metal salt and a quaternary ammonium salt.

  Moreover, as a material of the silicone rubber which comprises a conductive elastic layer, it is more preferable to use the liquid silicone rubber used for casting. The liquid silicone rubber is excellent in processability and has no dimensional stability due to the absence of by-products accompanying the curing reaction. Moreover, among the liquid silicone rubbers, it is more preferable to use a silicone rubber obtained by heat-curing an addition reaction cross-linkable liquid silicone rubber because the physical properties after curing are stable.

  This addition reaction crosslinking type liquid silicone rubber contains, for example, an organopolysiloxane represented by the following formula (1) and an organohydrogenpolysiloxane represented by the following formula (2). Furthermore, in addition to the materials of the following formulas (1) and (2), a catalyst and other additives can be appropriately mixed and used in this addition reaction cross-linkable liquid silicone rubber.

(In the formula, R ¹ and R ² are alkenyl groups which may be the same or different from each other, and x is a positive integer.)
The organopolysiloxane represented by the formula (1) is a base polymer of addition reaction cross-linkable liquid silicone rubber, and its weight average molecular weight is not particularly limited, but is preferably 100,000 or more and 1,000,000 or less, and 400,000 or more and 700,000 or less. Is more preferable. Furthermore, from the viewpoint of processing characteristics and characteristics of the liquid silicone rubber composition obtained, the viscosity (25 ° C.) of the organopolysiloxane is preferably 10 Pa · s or more, more preferably 50 Pa · s or more as the lower limit. The upper limit is preferably 300 Pa · s or less, and more preferably 250 Pa · s or less.

  The alkenyl group of the organopolysiloxane represented by the formula (1) is a site that reacts with the active hydrogen of the organohydrogenpolysiloxane to form a crosslinking point. The type is not particularly limited, but is preferably selected from a vinyl group and an allyl group, and a vinyl group is particularly preferable because of its high reactivity with active hydrogen.

(In the formula, y is a positive integer of 2 or more, and z is a positive integer.)
The organohydrogenpolysiloxane represented by the formula (2) functions as a crosslinking agent for addition reaction in the curing step. The number of hydrogen atoms bonded to silicon atoms in one molecule is 2 or more. From the viewpoint of excellent curing reaction, the number of hydrogen atoms bonded to silicon atoms in one molecule is 3 or more. Is preferred.

  Moreover, there is no restriction | limiting in particular in the molecular weight of organohydrogenpolysiloxane, For example, the thing of the weight average molecular weight of 1000-10000 can be used. In order to appropriately perform the curing reaction, an organohydrogenpolysiloxane having a relatively low molecular weight (for example, a weight average molecular weight of 1000 or more and 5000 or less) is preferable.

  By using a liquid silicone rubber as a material and subjecting the conductive elastic layer obtained by casting to a secondary curing treatment, the reaction can be completed and the low-molecular siloxane can be removed effectively.

  In the present invention, in the conductive elastic layer 2, the total amount of the extract when immersed in methyl ethyl ketone measured under the following conditions is 4% by mass or less of the mass of the conductive elastic layer 2 before being immersed in methyl ethyl ketone (MEK). It is necessary to become. When the conductive elastic layer is composed of a plurality of layers, the “total amount of extract when immersed in methyl ethyl ketone” is measured for the entire conductive elastic layer composed of a plurality of layers. Below, this measuring method is described.

First, the mass (M _st ) of the manufactured elastic roller is measured. Next, the elastic roller is submerged in a graduated cylinder containing MEK whose temperature has been adjusted to 25 ± 5 ° C., and left to stand for 24 hours. Thereafter, the elastic roller is taken out of the MEK and left to stand for 24 hours under conditions of 24 ° C. and 40% RH to dry the MEK. Thereafter, the mass (M _ext ) of the elastic roller is measured, and the amount of MEK extract (W _ext : mass%) is obtained by the following formula 1.
W _ext = {(M _st −M _ext ) / (M _st −M _core )} × 100 (Formula 1)
(In the formula, M _st represents the mass of the elastic roller before the MEK immersion test, M _ext represents the mass of the elastic roller after the MEK immersion test, and M _core represents the mass of the conductive support.)
When the total amount of the above extract exceeds 4% by mass, it is difficult to completely suppress the seepage of the residue on the roller surface even if the conductive coating layer 3 is provided on the conductive elastic layer 2. There is a risk of contamination. The total amount of the extract is preferably 3% by mass or less, more preferably 2% by mass or less, and further preferably 1.5% by mass or less. By making the total amount of the extract within these ranges, the leaching of the residue to the roller surface can be almost effectively eliminated.

(Conductive coating layer)
Although it does not necessarily limit as a material of the electroconductive coating layer 3, since it is excellent in elasticity and workability, it is preferable to set it as the material containing the polyurethane resin containing isocyanate and a polyol.
Examples of the polyol include polyether polyol having a polyhydroxyl group at the terminal, polyester polyol, and polyether polyester polyol which is a copolymer of both. In addition, polyolefin polyols such as polybutadiene polyol and polyisoprene polyol, so-called polymer polyols obtained by polymerizing ethylenically unsaturated monomers in polyols, and the like can be used.

  Similarly, as the isocyanate, polyisocyanate used for production of general flexible polyurethane foam or urethane elastomer can be used. As this polyisocyanate, for example, tolylene diisocyanate (TDI), crude TDI, or 4,4'-diphenylmethane diisocyanate (MDI) can be used. Moreover, crude MDI, C2-C18 aliphatic polyisocyanate, and C4-C15 alicyclic polyisocyanate can be used. Furthermore, mixtures and modified products of the polyisocyanates listed above, for example, prepolymers obtained by partially reacting with polyols can be used.

  Further, a conductive agent may be added to make the conductive coating layer conductive. Examples of the conductive agent to be added include carbon, graphite, copper, aluminum, nickel, iron powder, and metal oxide. Furthermore, it is also preferable to add spherical fine particles in order to impart toner transportability to the conductive roller. Examples of the particles include polymethacrylate, polystyrene, polyurethane and the like, and the average particle size is preferably in the range of 3 μm to 30 μm.

  The coating liquid used when forming these conductive coating layers is preferably used as a mixed solvent mainly composed of methyl ethyl ketone, and is mixed and dispersed by a bead mill or a pot mill to adjust the viscosity to be suitable for the coating work. Then apply. The coating liquid can be applied by forming a uniform coating film on the conductive elastic layer 2 using a dipping method, a roll coating method, a spray coating method or the like.

  In the present invention, in order to prevent the content component from oozing out from the conductive elastic layer 2, it is necessary that the 100% modulus of the conductive coating layer be in the range of 2 MPa to 10 MPa. The 100% modulus is preferably 3 MPa or more and 7 MPa or less. When the 100% modulus is 3 MPa or more and 7 MPa or less, optimization can be achieved from the viewpoint of elasticity of the conductive coating layer and prevention of exudation of content components from the conductive elastic layer 2. In addition, the measurement of 100% modulus of the present invention is measured according to JIS-K6251. When the conductive coating layer is composed of a plurality of layers, this “100% modulus” is measured for the entire conductive coating layer composed of a plurality of layers.

  At the same time, the thickness of the conductive coating layer needs to be 5 μm or more and 15 μm or less. The film thickness of the conductive coating layer is preferably in the range of 8 μm to 12 μm. When the thickness of the conductive coating layer is 8 μm or more and 12 μm or less, the roller of the present invention can have more excellent rotation characteristics and contact property to the photoreceptor.

  When the 100% modulus is less than 2 MPa or the film thickness is less than 5 μm, the degree of cross-linking of the polyurethane resin becomes small, and the component exuded from the conductive elastic layer 2 penetrates into the conductive coating layer and the surface thereof. Appearing on the photoconductor, and the photoconductor is easily contaminated. When the 100% modulus exceeds 10 MPa or the film thickness exceeds 15 μm, the hardness of the conductive coating layer increases and the toner is deteriorated to make it impossible to balance high resolution and high durability. As a result, an image defect occurs.

  In addition, the measurement of the film thickness of the electroconductive coating layer in this invention produced the sample which cut off a dotted-line part with a blade and can observe the cross section of an electroconductive coating layer, as FIG. 3 shows. Next, the cross section of this sample was observed with a digital HF microscope VH-8000 manufactured by Keyence Corporation. And the film thickness was measured according to the following criteria by the constituent material of the conductive coating layer.

  (I) When the conductive coating layer does not contain fine particle material (conductive agent, spherical fine particles, etc.), from the surface of the conductive coating layer constituting the outermost layer, the inner layer (conductive elastic layer, The distance to the interface of the intermediate layer was measured. And the shortest part among this distance was measured as a film thickness of the electroconductive coating layer of this invention. FIG. 5A shows this measurement method, where 1b represents a conductive elastic layer, 1c represents an intermediate layer (such as an adhesive layer), and 1d represents a conductive coating layer constituting the outermost layer. As shown in FIG. 5 (a), the portion with the smallest film thickness in the conductive coating layer 1d constituting the outermost layer was measured as the film thickness B of the present invention.

  (Ii) In the case where the conductive coating layer contains a particulate material, and there is a flat portion where the particulate material does not exist on the surface of the conductive coating layer, the measurement was performed as shown in FIG. That is, in FIG. 2, 1b is a conductive elastic layer, 1c is an intermediate layer (such as an adhesive layer), 1d is a conductive coating layer constituting the outermost layer, and 1a is a fine particle material contained in the conductive coating layer 1d. To express. As shown in FIG. 2, the distance from the surface to the interface of the inner layer (conductive elastic layer, intermediate layer, etc.) with respect to the flat portion of the surface of the conductive coating layer 1d without the spherical particles is set as follows. It was measured. And the part with the smallest film thickness among this distance was measured as the film thickness B of this invention.

(Iii) When the conductive coating layer contains a particulate material and the particulate materials are close to each other and there is no flat portion on the surface, the portion where the film is the most concave (the portion with the smallest film thickness) ) Was measured as the film thickness B of the present invention. FIG. 5B shows this measurement method. 1b is a conductive elastic layer, 1c is an intermediate layer (such as an adhesive layer), 1d is a conductive coating layer constituting the outermost layer, and 1a is a conductive layer. The particulate material contained in the coating layer 1d is represented. As shown in FIG. 5B, the smallest film thickness portion in the conductive coating layer 1d constituting the outermost layer was measured as the film thickness B of the present invention.
When the conductive coating layer is composed of a plurality of layers, this “film thickness of the conductive coating layer” is measured for the entire conductive coating layer composed of a plurality of layers.

(Electrophotographic equipment)
The conductive roller of the present invention can be used as a desired roller according to its characteristics. For example, the conductive roller can be used as a developing roller, a charging roller, or a transfer roller installed around a photosensitive member in an electrophotographic apparatus. is there.
FIG. 4 shows an example of a schematic view of a contact developing type electrophotographic apparatus incorporating the conductive roller of the present invention as a developer carrying roller.

In this electrophotographic apparatus, the following constituent members are combined into a single cartridge, which is a cartridge that can be integrally replaced in the electrophotographic apparatus.
-Photosensitive drum 31 as an image forming body
・ Primary charging roller 32
・ Developer carrying roller 33
・ Developer supply roller 34
Toner layer thickness regulating member 35 which is a developer layer thickness regulating member
・ Stirring blade 36
A toner 37 that is a developer.

  In the electrophotographic apparatus of FIG. 4, the photosensitive drum 31 uniformly charged by the primary charging roller 32 rotates in the direction of the arrow. Then, a laser beam 40 on which recording information is placed is irradiated between the primary charging roller 32 and the developer supply roller 33 to form a latent image. On the other hand, the toner 37 sent to the developer supply roller 34 by the stirring blade 36 is uniformly coated on the surface of the developer carrying roller 33 by the toner layer thickness regulating member 35 and is carried to the surface of the photosensitive drum 31. In the electrophotographic apparatus of FIG. 4, the conductive roller of the present invention is used as the developer carrying roller 33. Next, the latent image formed on the surface of the photosensitive drum 31 is visualized as a toner image.

  When the photosensitive drum 31 further rotates and the toner image reaches the transfer region, the toner image is transferred to the recording medium 43 such as paper by the transfer roller 42 that is opposed to the photosensitive drum 31. The toner remaining on the surface of the photosensitive drum 31 without being transferred to the recording medium 43 is removed by the cleaning elastic member 38 and then uniformly charged by the primary charging roller 32 again.

  The unfixed toner image transferred to the recording medium 43 passes between the fixing roller 44 and the pressure roller 45, is fixed to the recording medium by pressure and heat, and is discharged from the electrophotographic apparatus.

  On the other hand, toner remaining on the surface of the developer carrying roller 31 without being used for development is returned to the developing container 41 while being carried on the surface. Inside the developer container 41, the developer supply roller 34 removes toner remaining on the surface of the developer carrying roller 33 from the surface of the developer carrying roller 33 and supplies new toner to the surface of the developer carrying roller 33. The new toner supplied to the surface of the developer carrying roller 33 is transported to the development area after the thickness of the toner coated by the toner layer thickness regulating member 35 is uniformly adjusted. By repeating this, the developer carrying roller 33 always coats new toner uniformly to develop the electrostatic latent image.

Hereinafter, the present invention will be described in more detail with reference to examples. In addition, these do not limit this invention at all.
(Preparation of conductive roller 1)
A φ8 mm stainless steel support (conductive support) was placed concentrically in a cylindrical mold having an inner diameter of 16 mm. Next, an addition reaction crosslinking type liquid silicone rubber (manufactured by Toray Dow Corning Co., Ltd .; volume resistivity 10 ⁷ Ω · cm) is cast as a conductive elastic layer material, and then placed in an oven at 130 ° C. for 20 minutes to heat and cure. Molded. Thereafter, after removing the cylindrical mold, a secondary curing treatment was performed in an oven at 200 ° C. for 4 hours to obtain a conductive roller 1 having a conductive elastic layer thickness of 4 mm.

(Preparation of conductive roller 2)
A conductive roller 2 having a conductive elastic layer thickness of 4 mm was obtained in the same manner as the method for manufacturing the conductive roller 1 except that the temperature of the secondary curing treatment was lowered to 160 ° C.

(Preparation of conductive roller 3)
A conductive roller 3 having a conductive elastic layer thickness of 4 mm was obtained in the same manner as the method for manufacturing the conductive roller 1 except that the secondary curing treatment was not performed.

(Preparation of coating solution 1)
A polyurethane resin (manufactured by Nippon Polyurethane Co., Ltd .; Nipponporan 5033 (trade name)) was diluted with methyl ethyl ketone so that the solid content concentration was 15% by mass to prepare a coating solution. Next, carbon black (manufactured by Mitsubishi Chemical Corporation: MA77 (trade name)) was added as a conductive agent to 100 parts by mass of the solid content in the coating solution so as to be 35 parts by mass. Further, polyurethane particles (manufactured by Negami Kogyo Co., Ltd .; Art Pearl C-400 (trade name); transparent) were added as a non-conductive filler so as to be 20 parts by mass. Thereafter, after sufficiently dispersing the above coating liquid, after adding a curing agent (manufactured by Nippon Polyurethane; Coronate L (trade name)) so as to be 10 parts by mass with respect to 100 parts by mass of the polyurethane resin. The mixture was stirred to obtain coating solution 1.

(Preparation of coating solution 2)
A polyurethane resin (manufactured by Nippon Polyurethane Co., Ltd .; Nipponporan 5033 (trade name)) was diluted with methyl ethyl ketone so that the solid content concentration was 10% by mass to prepare a coating solution. Next, carbon black (manufactured by Mitsubishi Chemical Corporation; MA77 (trade name)) was added as a conductive agent to 100 parts by mass of the solid content in the coating solution so as to be 35 parts by mass. Further, polyurethane particles (manufactured by Negami Kogyo Co., Ltd .; Art Pearl C-400 (trade name); transparent) were added as a non-conductive filler so as to be 20 parts by mass. Thereafter, after sufficiently dispersing the above coating liquid, after adding a curing agent (manufactured by Nippon Polyurethane; Coronate L (trade name)) so as to be 10 parts by mass with respect to 100 parts by mass of the polyurethane resin. The mixture was stirred to obtain coating solution 2.

(Preparation of coating solution 3)
A polyurethane resin (manufactured by Nippon Polyurethane Co., Ltd .; Nipponporan 5033 (trade name)) was diluted with methyl ethyl ketone so as to have a solid content concentration of 40% by mass to prepare a coating solution. Next, carbon black (manufactured by Mitsubishi Chemical Corporation; MA77 (trade name)) was added as a conductive agent to 100 parts by mass of the solid content in the coating solution so as to be 35 parts by mass. Further, urethane particles (manufactured by Negami Kogyo Co., Ltd .; Art Pearl C-400 (trade name); transparent) were added as a non-conductive filler so as to be 20 parts by mass. Thereafter, after sufficiently dispersing the above coating liquid, after adding a curing agent (manufactured by Nippon Polyurethane; Coronate L (trade name)) so as to be 10 parts by mass with respect to 100 parts by mass of the polyurethane resin. The mixture was stirred to obtain a coating liquid 3.

(Preparation of coating solution 4)
A polyurethane resin (manufactured by Nippon Polyurethane Co., Ltd .; Nipponporan 5033 (trade name)) was diluted with methyl ethyl ketone so as to have a solid content concentration of 8% by mass to prepare a coating solution. Next, carbon black (manufactured by Mitsubishi Chemical Corporation; MA77 (trade name)) was added as a conductive agent to 100 parts by mass of the solid content in the coating solution so as to be 35 parts by mass. Further, polyurethane particles (manufactured by Negami Kogyo Co., Ltd .; Art Pearl C-400 (trade name); transparent) were added as a non-conductive filler so as to be 20 parts by mass. Thereafter, after sufficiently dispersing the above coating liquid, after adding a curing agent (manufactured by Nippon Polyurethane; Coronate L (trade name)) so as to be 10 parts by mass with respect to 100 parts by mass of the polyurethane resin. The mixture was stirred to obtain a coating liquid 4.

(Adjustment of coating solution 5)
A polyurethane resin (manufactured by Nippon Polyurethane Co., Ltd .; Nipponporan 5033 (trade name)) was diluted with methyl ethyl ketone so that the solid content concentration was 50% by mass to prepare a coating solution. Next, carbon black (manufactured by Mitsubishi Chemical Corporation; MA77 (trade name)) was added as a conductive agent to 100 parts by mass of the solid content in the coating solution so as to be 35 parts by mass. Further, polyurethane particles (manufactured by Negami Kogyo Co., Ltd .; Art Pearl C-400 (trade name); transparent) were added as a non-conductive filler so as to be 20 parts by mass. Thereafter, after sufficiently dispersing the above coating liquid, after adding a curing agent (manufactured by Nippon Polyurethane; Coronate L (trade name)) so as to be 10 parts by mass with respect to 100 parts by mass of the polyurethane resin. The mixture was stirred to obtain a coating liquid 4.

(Adjustment of coating solution 6)
A polyurethane resin (manufactured by Nippon Polyurethane Co., Ltd .; Nipponporan 5033 (trade name)) was diluted with methyl ethyl ketone so as to have a solid content concentration of 7% by mass to prepare a coating solution. Next, carbon black (manufactured by Mitsubishi Chemical Corporation; MA77 (trade name)) was added as a conductive agent to 100 parts by mass of the solid content in the coating solution so as to be 35 parts by mass. Further, urethane particles (manufactured by Negami Kogyo Co., Ltd .; Art Pearl C-400 (trade name); transparent) were added as a non-conductive filler so as to be 20 parts by mass. Thereafter, after sufficiently dispersing the above coating liquid, after adding a curing agent (manufactured by Nippon Polyurethane; Coronate L (trade name)) so as to be 10 parts by mass with respect to 100 parts by mass of the polyurethane resin. The mixture was stirred to obtain a coating liquid 4.

Example 1
After the conductive roller 1 was immersed in the coating liquid 1, the conductive coating layer was applied to the conductive roller 1 by lifting. The thickness of the conductive coating layer after drying was 10 μm, and the 100% modulus was 4.01 MPa.

(Example 2)
After immersing the conductive roller 2 in the coating liquid 1, the conductive coating layer was applied on the conductive roller 2 by lifting. The thickness of the conductive coating layer after drying was 10 μm, and the 100% modulus was 4.01 MPa.

(Example 3)
After immersing the conductive roller 1 in the coating liquid 2, the conductive coating layer was applied on the conductive roller 1 by lifting. The thickness of this conductive coating layer after drying was 7 μm, and the 100% modulus was 3.01 MPa.

Example 4
After immersing the conductive roller 1 in the coating liquid 3, the conductive coating layer was applied on the conductive roller 1 by lifting. The thickness of the conductive coating layer after drying was 15 μm, and the 100% modulus was 9.70 MPa.

(Example 5)
After the conductive roller 1 was immersed in the coating liquid 4, the conductive coating layer was applied on the conductive roller 1 by pulling up. The thickness of this conductive coating layer after drying was 5 μm, and the 100% modulus was 2.10 MPa.

(Comparative Example 1)
After immersing the conductive roller 3 in the coating liquid 1, the conductive coating layer was applied on the conductive roller 3 by lifting. The thickness of the conductive coating layer after drying was 10 μm, and the 100% modulus was 4.01 MPa.

(Comparative Example 2)
After the conductive roller 1 was immersed in the coating liquid 5, the conductive coating layer was applied on the conductive roller 1 by pulling up. The thickness of the conductive coating layer after drying was 16 μm, and the 100% modulus was 10.50 MPa.

(Comparative Example 3)
After immersing the conductive roller 1 in the coating liquid 6, the conductive coating layer was applied on the conductive roller 1 by lifting. The thickness of the conductive coating layer after drying was 1.9 μm, and the 100% modulus was 1.90 MPa.

(Roller evaluation)
The conductive roller manufactured as described above was incorporated in an electrophotographic apparatus. Then, with regard to the final product recorded 8000 sheets continuously, whether or not the image has an abnormal density portion such as white spots (photoconductor contamination), streaks in the paper passing direction occur in the image. (Image evaluation) was checked. Also, it was confirmed by visual observation whether toner filming had occurred on the surface of the developing roller after completion of recording. The evaluations of “photoconductor contamination” and “image evaluation” were “◯: no problem” and “×: observed”. In Table 1 above, when both “contamination of photoconductor” and “image evaluation” obtained “◯” or “Δ”, it was determined that there was no problem in use.
In Table 1, the “100% modulus” of the conductive coating layer, the “elution amount into the methyl ethyl ketone” and the “film thickness of the conductive coating layer” of the conductive elastic layer are as described above (for carrying out the invention). The best mode was measured by the method described in the above.

  From the results of Table 1 above, in all of Examples 1 to 5, the 100% modulus of the conductive coating layer was 2 MPa or more and 10 MPa or less, and the film thickness was 5 μm or more and 15 μm or less. In all of Examples 1 to 5, since the extraction amount of methyl ethyl ketone in the conductive elastic layer was 4% by mass or less, the photoreceptor was not contaminated with “◯” or “Δ”, and neither image evaluation nor toner deterioration was observed. The image evaluation was “◯” or “Δ”, and good results were obtained.

  On the other hand, in Comparative Example 1, the amount of methyl ethyl ketone extracted exceeded 4% by mass, and in Comparative Example 3, the coating resin layer had a film thickness of less than 5 μm and a 100% modulus of less than 2 MPa. For this reason, in Comparative Examples 1 and 3, the component exuded from the conductive elastic layer penetrated into the conductive coating layer to cause contamination of the photoreceptor, and “contamination of the photoreceptor” was “x”. . Moreover, in Comparative Example 2, the film thickness of the conductive coating layer exceeded 15 μm, and the 100% modulus exceeded 10 MPa. For this reason, in Comparative Example 2, the “image evaluation” resulted in an unclear image due to toner deterioration, resulting in “x”.

It is a conceptual diagram showing the cross section of an example of the electroconductive roller of this invention. It is the schematic which shows the film thickness measuring method of the electroconductive coating layer of the electroconductive roller of this invention. It is the schematic which shows the film thickness measuring method of the electroconductive coating layer of the electroconductive roller of this invention. It is the schematic showing an example of the electrophotographic apparatus provided with the electroconductive roller of this invention. It is the schematic which shows the film thickness measuring method of the electroconductive coating layer of the electroconductive roller of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Conductive elastic layer 3 Coating resin layer 1a Spherical particle 1b Conductive elastic layer 1c Intermediate layer 1d Conductive coating layer 31 Photosensitive drum 32 Primary charging roller 33 Developer carrying roller 34 Developer supply roller 35 Toner Layer regulating member 36 Agitation blade 37 Toner 41 Developer container 42 Transfer roller 43 Recording medium 44 Fixing roller

Claims (4)

A conductive roller having a conductive support, a conductive elastic layer provided on the outer periphery of the conductive support, and a conductive coating layer provided on the outer periphery of the conductive elastic layer,
The total amount of the extract when the conductive elastic layer is immersed in methyl ethyl ketone is 4% by mass or less of the mass of the conductive elastic layer before being immersed in the methyl ethyl ketone,
A conductive roller, wherein a 100% modulus of the conductive coating layer is in a range of 2 MPa or more and 10 MPa or less, and a film thickness of the conductive coating layer is 5 μm or more and 15 μm or less.   The conductive roller according to claim 1, wherein the conductive elastic layer includes a silicone rubber obtained by heating and curing an addition reaction cross-linkable liquid silicone rubber.   The conductive roller according to claim 1, wherein the conductive coating layer includes a polyurethane resin containing an isocyanate and a polyol.   4. The conductive roller according to claim 1, wherein the conductive coating layer is formed using a coating liquid containing methyl ethyl ketone. 5.

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