JP2001142294A - Electrophotographic roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability of an electrophotographic roller. SOLUTION: The roller is produced by forming an elastic layer on the outer face of a conductive core body, forming a primer layer only in both end parts of the elastic layer on the outer face of the elastic layer which does not influence the image region, and further forming a resin layer on the surface. Even when an elastic layer of low hardness is used, wrinkles or peeling of the film of the resin layer can be prevented, and the obtained roller has excellent durability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller incorporated in an electrophotographic apparatus such as a copying machine, a printer or a facsimile receiving apparatus, and more particularly to a developing roller used in a developing apparatus employing a non-magnetic developing method.

[0002]

2. Description of the Related Art In an apparatus employing an electrophotographic system,
The developing roller has a function of conveying toner to an electrostatic latent image carrier such as a photoconductor. FIG. 1 is an explanatory diagram schematically showing a developing roller 1 used in a non-magnetic one-component contact developing method using a non-magnetic one-component toner and a peripheral structure thereof. The developing roller 1 has a conductive elastic layer 3 formed around a conductive shaft 2 made of SUS or aluminum alloy, and a surface formed of a synthetic resin on the conductive elastic layer 3 as necessary. It is composed of layer 4. The toner 6 stored in the toner container 5 is reliably carried on the surface of the developing roller 1 by the supply roller 7, and is pressed by a regulating member 8 such as a regulating blade attached to the toner container 5 to contact and frictionally charge. After the toner thin layer,
The thin toner layer adheres to the electrostatic latent image on the surface of the photoconductor 9 to form a toner image. In many cases, a DC voltage is applied to the developing roller 1, the supply roller 7, and the regulating member 8 in order to adjust their surface potential. Although not shown here, leakage of toner from the toner container 5 not only contaminates the surroundings but also causes a large deterioration in image quality. Therefore, toner leakage is prevented at both axial ends of the developing roller. A sealing mechanism is provided as needed.

[0003]

Needless to say, in recent years, it has become increasingly important to reduce the size and weight of an electrophotographic apparatus and to save energy. In order to reduce the size and weight of the device and save energy, it is necessary to reduce the drive system of the roller. For this reason, the hardness of the conductive elastic layer is reduced as the developing roller, and the friction between the developing roller and the photoconductor is reduced. It is desired to reduce the resistance and the load on the drive system. Also, from the viewpoint of image quality durability, there is a great merit of lowering the hardness of the conductive elastic layer because toner deterioration is small. However, if the hardness of the conductive elastic layer is reduced, its abrasion resistance is reduced, so that the image quality is deteriorated during long-term use, and the toner seal portions at both ends of the roller are worn, and toner leakage occurs. A new problem arises. For this reason, conventionally, an attempt has been made to improve the abrasion resistance of the conductive elastic layer and the charging performance for the toner by forming a surface layer coated with one or more resin layers on the surface of the conductive elastic layer. I have. However, even when this method is used, if the difference in hardness between the conductive elastic layer and the surface layer is large, the surface layer is peeled off at the toner seal portions at both ends in the axial direction of the roller, or the toner leaks due to wrinkles of the surface layer. Therefore, it is difficult to greatly reduce the hardness of the conductive elastic layer.

As a means for solving the above-mentioned peeling of the surface layer or wrinkling of the surface layer, it has been reported to improve the interfacial adhesion by using an adhesive at the interface between the elastic layer and the surface layer. In this case, the resistance of the adhesive is high, and it is not easy to control the roller resistance in the medium resistance region required for the developing roller.

The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to provide a developing roller having low hardness, high durability of toner seal portions at both ends, and improved toner leakage.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, the primer layer is provided only on both ends which do not affect the image area of the low hardness elastic layer and the surface layer. By forming the above, it has been found that the advantage of lowering the hardness of the conductive elastic layer, that is, both suppression of toner deterioration and durability of the toner seal portion can be achieved,
The present invention has been completed. That is, the present invention relates to an electrophotographic roller, in which an elastic layer is provided on the outer periphery of a conductive core, and then a primer layer is formed only on both ends of the elastic layer. A roller in which a resin layer is formed on the entire surface (claim 1).

The hardness of the elastic layer is 3 to 3 in JISA hardness.
The roller according to claim 1, wherein the angle is 0 °.

(3) The polymer in which the elastic layer has (A) at least one alkenyl group in a molecule and a repeating unit constituting a main chain is an oxyalkylene unit or a saturated hydrocarbon unit. And (B) a curing agent having at least two hydrosilyl groups in a molecule, (C) a hydrosilylation catalyst, and (D) a curable composition containing a conductivity-imparting agent as a main component. Item 3. The roller according to any one of Items 1 to 2.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, various embodiments according to the present invention will be described.

The developing roller according to the present invention has a diameter of 1 to 12 mm.
SUS of about mm, an elastic layer is provided concentrically around a conductive core made of aluminum or conductive resin,
Further, a primer layer is formed only on both end portions of the outer peripheral surface which do not affect the image area. Further, the entire surface of the elastic layer including the primer layer is coated with a surface layer of 10 μm to 300 μm
It is formed by coating with a predetermined thickness of about m. By forming the primer layer only on both end portions that do not affect the image area, it is possible to omit the control of the resistance of the primer.

The type of primer used in the present invention is as follows:
It can be appropriately selected in consideration of the adhesiveness to each of the elastic layer and the surface layer. Specific examples include primers such as synthetic rubber, acrylic, urethane, epoxy, silicone resin, silane or modified silane which are generally used for various resins.

As a method of applying the primer, a portion other than the portion to be applied is masked, and a dipping method, a roll coater method, a spray coating method, or the like can be used. From the viewpoint of inexpensive production, a roll coater method capable of disposing a transfer roll only at a desired portion or supplying a coating liquid only to a desired portion is preferable.

Although the specific main component of the surface layer is not particularly limited, it contains an -NHCO- bond from the viewpoint of improving the charging characteristics of the negatively charged toner, and contains polycarbonate from the viewpoint of environmental stability. -ROCO like skeleton
_What is necessary is just to consist of a resin composition having a main composition of a resin having a repeating unit of _2-, even if it is a blend resin of polyamide or polyurethane and polycarbonate,
Polycarbonate urethane or the like having both —NHCO— bonds and —ROCO ₂ — repeating units in one molecule may be used.

As the above-mentioned polycarbonate urethane,
It is preferable that the —R group of the —ROCO ₂ — skeleton is an alicyclic group or an alkyl group. Among these, it is preferable that the -R group be an alkyl group from the viewpoint that a low hardness and a low water absorption of the surface layer can be obtained in a well-balanced manner.

Further, the above-mentioned polycarbonate urethane comprises:
A compound obtained by reacting a polycarbonate polyol with a polyisocyanate. The polycarbonate polyol is obtained by condensation of a polyhydric alcohol with phosgene, chloroformate, dialkyl carbonate or diallyl carbonate. As the polyhydric alcohol, it is desirable to use 1,6-hexanediol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, or the like, and the number average molecular weight (Mn) of the polycarbonate polyol is preferably , About 300
It is desirably in the range of 15,000. The polycarbonate polyol is preferably used alone, but may be used in combination with a polyester polyol, a polyether polyol or a polyester-polyether polyol.

The polyisocyanates which react with the above-mentioned polycarbonate polyols include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), xylene diisocyanate (XDI), and hexamethylene diisocyanate (HD
I), hydrogenated MDI, hydrogenated TDI or isophorone diisocyanate (IPDI) is used. Among these, hydrogenated MDI is considered in consideration of the balance between availability, cost, and various characteristics required for the developing roller.
Alternatively, it is preferable to use IPDI.

On the other hand, as a main component of the surface layer, a resin composition containing an acrylic-vinyl carboxylate-based copolymer as a main component can be used from the viewpoint of reducing environmental fluctuation of roller resistance due to moisture absorption or the like. . In the acrylic-vinyl carboxylate copolymer, the total amount of the acrylate monomer component, the methacrylate monomer component and the vinyl carboxylate monomer component is 50% by weight or more, preferably 80% by weight or more in the resin component. Wherein the vinyl carboxylate monomer component is contained in the resin component in an amount of 3% by weight or more, preferably 5% by weight or more, more preferably 10% by weight or more.

Examples of the acrylate monomer component include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like, from the viewpoint that polymerization proceeds favorably.

From the viewpoint that the polymerization proceeds favorably as the methacrylate monomer component,
Examples thereof include methyl methacrylate, ethyl methacrylate, and butyl methacrylate. Among these, methyl methacrylate is preferred from the viewpoint of availability.

The vinyl carboxylate monomer component includes vinyl acetate, vinyl propionate, vinyl valerate, vinyl isovalerate and the like from the viewpoint that polymerization proceeds favorably. Among these, it is preferable to use vinyl acetate from the viewpoint of availability and favorable negative charging of the toner.

The particles to be added are not particularly limited, but when used as a developing roller of an electrophotographic apparatus using a negatively charged toner, particles such as urethane, nylon, and acrylic having a polarity opposite to that of the toner may be used. It is preferable from the viewpoint of improving chargeability. When it is used as a developing roller of an electrophotographic apparatus using a positively charged toner, fluorine and silicone particles are preferable.

The material of the elastic layer is not particularly limited as long as it can reduce the hardness, and materials such as NBR, silicone, and urethane can be used. As a material for the elastic layer, (A) is used as an elastic layer material from the viewpoint of reducing hardness without using a plasticizer which has a danger of bleeding to a contact member such as a photoconductor
A polymer having at least one alkenyl group in the molecule and a repeating unit constituting the main chain being an oxyalkylene unit or a saturated hydrocarbon unit, and (B) having at least two hydrosilyl groups in the molecule A curing agent and (C)
A reaction product of a curable composition containing a hydrosilylation catalyst and (D) a conductivity-imparting agent as main components is particularly preferable.

The polymer of the component (A) in the curable composition is a component which is cured by a hydrosilylation reaction with the component (B) and has at least one alkenyl group in the molecule. Occurs to become a polymer and harden. The number of alkenyl groups contained in the component (A) must be at least one in view of hydrosilylation reaction with the component (B), but from the viewpoint of obtaining sufficient rubber elasticity, the number of In the case of a molecule having two alkenyl groups at both ends of the molecule and having a branch,
It is desirable that two or more alkenyl groups be present at the molecular terminals. The main repeating unit constituting the main chain of the component (A) is an oxyalkylene unit or a saturated hydrocarbon unit.

First, the case where the main repeating unit constituting the main chain of the component (A) is a polymer comprising an oxyalkylene unit will be described. At this time, when a small amount of the conductivity-imparting agent as the component (D) is added to the cured product, the volume resistivity of the cured product becomes 10 ⁸ Ωcm to 10 ⁹ Ωcm, which is preferable when used as a developing roller. . From the viewpoint of lowering the hardness of the cured product, an oxyalkylene polymer in which the repeating unit is an oxyalkylene unit, and an oxypropylene polymer in which the repeating unit is an oxypropylene unit are preferable.

Here, the oxyalkylene polymer refers to a polymer in which 30% or more, preferably 50% or more, of the units constituting the main chain are oxyalkylene units. The unit contained other than the oxyalkylene unit contains 2 units of active hydrogen used as a starting material in the production of the polymer.
Compounds having at least one such as ethylene glycol,
Units composed of bisphenol compounds, glycerin, trimethylolpropane, pentaerythritol and the like. When the repeating unit is an oxypropylene-based unit, it may be a copolymer (including a graft copolymer) with a unit composed of ethylene oxide, butylene oxide, or the like.

The molecular weight of such an oxyalkylene polymer is 500 to 50,000 in terms of number average molecular weight (Mn) from the viewpoint of improving the balance between reactivity and low hardness.
0, more preferably 1,000 to 40,000. In particular, those having a number average molecular weight of 5,000 or more,
Further, those having a molecular weight of 5,000 to 40,000 are preferable. When the number average molecular weight is less than 500, it becomes difficult to obtain sufficient mechanical properties (rubber hardness, elongation) and the like when the curable composition is cured. On the other hand, if the number average molecular weight is too large, the alkenyl group 1
Because the molecular weight per unit increases or the reactivity decreases due to steric hindrance, curing often becomes insufficient,
Further, the viscosity tends to be too high and the processability tends to be poor.

The alkenyl group contained in the oxyalkylene polymer is not particularly limited, but an alkenyl group represented by the following general formula (1) is particularly preferable in terms of excellent curability.

H ₂ C ＝ C (R ¹ )-(1) (wherein R ¹ is a hydrogen atom or a methyl group) One of the features of this curable composition is that it is easy to set the hardness to be low. In order to exhibit this characteristic, the number of alkenyl groups is preferably two or more at the molecular terminals. However, if the number of alkenyl groups is too large as compared with the molecular weight of the component (A), the composition becomes rigid and it is difficult to obtain good rubber elasticity.

Next, the case where the component (A) is a polymer in which the main repeating unit constituting the main chain is a saturated hydrocarbon-based unit will be described. This polymer is preferable in that it has a low water absorption and a cured product having a small environmental change in electric resistance is easily obtained. Further, similarly to the case of the oxyalkylene-based polymer, the component is a component which is cured by a hydrosilylation reaction with the component (B), and has at least one alkenyl group in the molecule. It becomes molecular and hardens. Further, (A)
The number of alkenyl groups contained in the component is required to be at least one from the viewpoint of hydrosilylation reaction with the component (B). However, from the viewpoint of obtaining good rubber elasticity, in the case of a linear molecule, It is preferable that two molecules are present at both ends. In the case of a molecule having a branch, it is preferable that two or more molecules exist at the molecular terminal.

Representative examples of the polymer in which the main repeating unit constituting the main chain is a saturated hydrocarbon-based unit include an isobutylene-based polymer, a hydrogenated isoprene-based polymer, and a hydrogenated butadiene-based polymer. . These polymers may contain a repeating unit of another component such as a copolymer, but at least 50% or more of a saturated hydrocarbon-based unit,
It is important that the content is preferably 70% or more, more preferably 90% or more, so as not to impair the characteristic of the saturated hydrocarbon based on low water absorption.

The molecular weight of the polymer of the component (A) in which the repeating unit constituting the main chain is a saturated hydrocarbon-based unit is about 500 to 50,000 in number average molecular weight (Mn), and more preferably 1,000. ~ 15,000
A liquid material having fluidity at room temperature is preferable in terms of ease of handling and workability.

The alkenyl group introduced into such a saturated hydrocarbon polymer is the same as in the case of the oxyalkylene polymer.

Therefore, preferred specific examples of the polymer as the component (A), which contains at least one alkenyl group in the molecule and in which the main repeating unit constituting the main chain is a saturated hydrocarbon-based unit, include: Two alkenyl groups at both ends
And a linear number average molecular weight (Mn) of 2,000 to
Examples thereof include polyisobutylene-based, hydrogenated polybutadiene-based, and hydrogenated polyisoprene-based polymers having 15,000 and Mw / Mn of 1.1 to 1.2.

The component (B) in the curable composition is not particularly limited as long as it is a compound having at least two hydrosilyl groups in the molecule, but the number of hydrosilyl groups in the molecule is too large. Then, even after curing, a large amount of hydrosilyl groups easily remain in the cured product, causing voids and cracks. Therefore, the number of hydrosilyl groups contained in the molecule is preferably 50 or less. Further, this number is from 2 to 30 in view of control of rubber elasticity of the cured product and storage stability.
, More preferably 2 to 20,
Furthermore, in terms of easily preventing foaming during curing, there are 20
The number is preferably 3 or more, and the most preferable range is 3 to 20 from the viewpoint that hardening failure hardly occurs even when the hydrosilyl group is deactivated.

In the present invention, the hydrosilyl group is
To have one means to have one H bonded to Si. In the case of SiH ₂ , it means to have two hydrosilyl groups, but H bonded to Si is preferably bonded to different Si. It is preferable in terms of curability and rubber elasticity.

The molecular weight of the component (B) is 30,000 or less in terms of number average molecular weight (Mn) from the viewpoint of dispersibility and roller workability when the conductivity-imparting agent (D) is added. It is preferably 20,000 or less, more preferably 15,000 or less. In consideration of the reactivity and compatibility with the component (A), the number average molecular weight is 300 to 1
Preferably it is at 000.

Regarding the component (B), since the cohesive force of the component (A) is greater than the cohesive force of the component (B), the phenyl group-containing modification is important in terms of compatibility. Styrene-modified products are preferred in terms of compatibility with the components and availability, and α-methylstyrene-modified products are preferred in terms of storage stability.

The hydrosilylation catalyst which is the component (C) is not particularly limited as long as it can be used as a hydrosilylation catalyst. Platinic acid (including complexes such as alcohols), various platinum complexes, rhodium,
Chloride of metals such as ruthenium, iron, aluminum, titanium and the like can be mentioned. Among these, chloroplatinic acid, a platinum-olefin complex, and a platinum-vinylsiloxane complex are preferable from the viewpoint of catalytic activity. These catalysts may be used alone or in combination of two or more.

The proportion of the component (B) to the component (A) in the curable composition as described above is such that the hydrosilyl group in the component (B) is 0.2 per mole of the alkenyl group in the component (A). When it is set so as to be present in an amount of from about 5.0 to about 5.0 moles, and more preferably from about 0.4 to about 2.5 moles, it is preferable to obtain good rubber elasticity.

The amount of component (C) used is as follows:
(A) 10 ^-1 to 1 mol of the alkenyl group in the component.
It is preferably used in the range of 10 ^-8 mol, particularly 10 ^-3 to 10 ^-6 mol. If the amount of the component (C) is less than 10 ^-8 mol, the reaction does not proceed. On the other hand, hydrosilylation catalysts
In general, it is expensive, corrosive, and has a property that a large amount of hydrogen gas is generated to cause foaming of the cured product. Therefore, it is preferable not to use more than 10 ^-1 mol.

Further, by adding a conductivity-imparting agent as the component (D) to the curable composition to form a conductive composition,
It is suitable as a developing roller. Examples of the conductivity-imparting agent of the component (D) include carbon black, metal fine powder, and organic compounds having a quaternary ammonium base, a carboxylic acid group, a sulfonic acid group, a sulfate group, a phosphate group, and the like. Or a polymer, an ether ester amide, or an ether imide polymer, an ethylene oxide-epihalohydrin copolymer, a compound having a conductive unit represented by methoxypolyethylene glycol acrylate, or an antistatic agent such as a polymer compound, Examples thereof include compounds capable of imparting conductivity. These conductivity imparting agents may be used alone or in combination of two or more.

The addition amount of the conductivity-imparting agent as the component (D) is preferably not more than 30% by weight based on the total amount of the components (A) to (C). preferable. On the other hand, in order to obtain a uniform volume resistivity, the addition amount is preferably 10% by weight or more, and the addition amount is determined so that the volume resistivity of the cured product is 10 ³ to 10 ¹⁰ Ωcm. Is preferred.

The curable composition includes the above (A) to
In addition to the component (D), a storage stability improver, for example, a compound having an aliphatic unsaturated bond, an organic phosphorus compound, an organic sulfur compound, a nitrogen-containing compound, a tin compound, or an organic peroxide may be added. good. Specific examples thereof include, but are not limited to, benzothiazole, thiazole, dimethylmalate, dimethylacetylenecarboxylate, 2-pentenenitrile, 2,3-dichloropropene, quinoline and the like. Among these, thiazole and dimethyl malate are particularly preferred from the viewpoint of achieving both pot life and rapid curing properties. The storage stability improvers may be used alone or in combination of two or more.

Further, a filler, a storage stabilizer, a plasticizer, an ultraviolet absorber, a lubricant, a pigment, and the like may be added to the curable composition from the viewpoint of improving processability and cost.

The elastic layer is made of an elastic material such as the curable composition, urethane rubber, or silicone rubber, for example,
Casting, injection molding, extrusion molding, etc. into a mold with a conductive core made of SUS or aluminum alloy at the center,
By heat-curing at an appropriate temperature and time, a conductive elastic layer is formed around the conductive core. In this case, post-curing may be performed after semi-curing.

In the developing roller according to the present invention, the primer is applied by a roll coater, dipping or spraying to a predetermined thickness only on both ends of the roller which does not affect the image area on the outer peripheral surface of the elastic layer. After drying at a predetermined temperature, the surface layer is similarly applied to a predetermined thickness by a roll coater, dipping or spraying, and dried at a predetermined temperature.

[0047]

EXAMPLES Hereinafter, the configuration of Example 1 according to the present invention will be described in detail, and then these Examples and Comparative Example 1 will be compared. (Embodiment 1) The developing roller used in this embodiment has a diameter of 1 mm.
An elastic layer having a thickness of 4 mm is provided concentrically around a 0 mm SUS shaft.

The following elastic layer is used as the elastic layer. (Elastic Layer 1) (A-1) 100 parts by weight of a terminal allylated polyoxypropylene polymer having a number average molecular weight (Mn) of 8,000 and a molecular weight distribution of 2.0, (B-1) polysiloxane System hardener (SiH value 0.36
(Mol / 100 g): 6.6 parts by weight, (C-1) 10% isopropyl alcohol solution of chloroplatinic acid: 0.06 parts by weight, (D-1) carbon black 3030B (manufactured by Mitsubishi Chemical Corporation): 8 parts by weight And a mixture obtained by defoaming under reduced pressure at a pressure of 10 mmHg or less for 120 minutes is coated on a shaft.
Let stand for 30 minutes in an environment of 0 ° C. and cure to a thickness of 4 mm
The elastic layer 1 made of the rubber elastic body was formed. A cylindrical sample (without a shaft) having a diameter of 30 mm and a height of 12.7 mm was produced using the composition, and the JIS A hardness measured at 23 ° C. was 13 °. Next, a predetermined amount of a primer solution having the following composition is weighed and uniformly stirred, and then applied by a dip method only to both ends of the elastic layer which does not affect the image quality, that is, only about 10 mm from the end of the elastic layer. , And then dried under an environment of 100 ° C. for 5 minutes,
A primer layer was formed. (Primer solution) (1) 5% organosilane A-1122 manufactured by Nippon Unicar (2) 95% IPA (isopropyl alcohol) Subsequently, the following surface layer was formed on the entire outer peripheral surface of the elastic layer including the primer layer. (Surface layer 1) (1) Urethane resin solution (product name “Y-258” manufactured by Dainichi Seika Co., Ltd.); 100 parts by weight of ether urethane (2) Urethane fine particles (product name “UP0904” manufactured by Dainichi Seika Co., Ltd .; average) 20 parts by weight The solid content of the compound obtained by the above-mentioned compounding was converted to DMF (N,
Dimethylformamide): Dilute to 5% with a mixed solvent of MEK (methyl ethyl ketone) = 1: 1 to make a solution that is left to stand for 1 hour. This solution was dipped around the elastic layer and dried to form a surface layer 1 having a thickness of about 20 μm. (Comparative Example 1) Example 1 except that no primer layer was formed.
A developing roller was produced in the same manner as described above. The developing rollers manufactured in Example 1 and Comparative Example 1 were incorporated into a micro printer 700N manufactured by Oki Data, and wrinkles and peeling off at the end of the roller were output every 5,000 sheets while outputting images of a constant pattern. , And the durability was evaluated up to 20,000 sheets.

[0049]

[Table 1] (Example 2 and Comparative Example 2) Next, a developing roller similar to that of Example 1 and Comparative Example 1 was prepared, except that the elastic layer 2 shown below was used as the elastic layer. (Example 2, Comparative Example 2). In Comparative Example 2, similarly to Comparative Example 1, no primer layer was formed. (Elastic Layer 2) (B-2) Polysiloxane based on 100 parts by weight of an allylated terminal polyoxypropylene polymer having a number average molecular weight (Mn) of 8,000 and a molecular weight distribution of 2.0 System hardener (SiH value 0.97
(Mol / 100 g): 2.7 parts by weight, (C-2) 10% isopropyl alcohol solution of chloroplatinic acid: 0.06 parts by weight, (D-2) carbon black 3030B (manufactured by Mitsubishi Chemical Corporation): 8 parts by weight And a mixture obtained by defoaming under reduced pressure at a pressure of 10 mmHg or less for 120 minutes is coated on a shaft.
Let stand for 30 minutes in an environment of 0 ° C. and cure to a thickness of 4 mm
An elastic layer made of a rubber elastic body was formed. A cylindrical sample (without a shaft) having a diameter of 30 mm and a height of 12.7 mm was manufactured using the composition, and the JIS A hardness measured at 23 ° C. was 21 °. From Table 1 above, it can be seen that the roller of the present example has no wrinkles or peeling of the surface layer as compared with the comparative example, and shows good durability.

Although the developing roller has been mainly described above, the present invention is not limited to this, and can be applied to a charging roller, a transfer roller, and the like.

[0051]

As described above, the roller of the present invention is provided with a low hardness elastic layer on the outer periphery of the conductive core, and on the outer periphery of the elastic layer,
By applying a primer treatment only to both end portions that do not affect the image area and then providing a surface layer, a developing roller having excellent toner seal portion durability can be obtained. Further, there is no need to consider the resistance control of the primer, and a developing roller having stable image characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a developing device and a photoconductor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 developing roller 2 conductive shaft 3 conductive elastic layer 4 surface layer 5 toner container 6 toner 7 supply roller 8 regulating member 9 photoreceptor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 71/00 C08L 71/00 A F16C 13/00 F16C 13/00 A B F term (Reference) 2H077 AD06 FA13 FA22 FA25 3J103 AA02 AA14 AA16 AA22 AA33 AA51 AA74 BA31 BA41 EA07 FA02 FA10 FA12 GA02 GA52 GA57 GA58 GA60 HA03 HA04 HA05 HA12 HA20 HA33 HA37 HA41 HA47 HA48 HA53 HA54 4F100 AA37 AB04 AH06B AH06A AK01B00 AK01B00 AK01B00 BA04 BA07 CA02B CA21B DA16 DB01C EH46 EJ65C GB51 GB90 JB12B JG01A JK07B JK12B JL00 JL08B YY00B 4J002 AC111 CH051 DA038 DA068 DA117 DD027 DE197 EX006 FD118 FD146 FD157 GM00

Claims (3)

[Claims] 1. An electrophotographic roller, wherein an elastic layer is provided on the outer periphery of a conductive core, a primer layer is formed only on both ends of the elastic layer, and an outer peripheral surface of the elastic layer further including the primer layer. A roller having a resin layer formed entirely. 2. The elastic layer has a hardness of 3 to 3 in terms of JISA hardness.
The roller according to claim 1, wherein the angle is 30 degrees. 3. The polymer according to claim 1, wherein the elastic layer has (A) a polymer having at least one alkenyl group in a molecule, and a repeating unit constituting a main chain is an oxyalkylene unit or a saturated hydrocarbon unit. A reaction product of a curable composition comprising (B) a curing agent having at least two hydrosilyl groups in a molecule, (C) a hydrosilylation catalyst, and (D) a conductivity-imparting agent as a main component. 5. The roller according to any one of 4.