JP2002173599A - Electroconductive thermoplastic elastomer composition and developing roller using the same and development apparatus using the roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing roller low in compression set declining tendency, free from surface bleeding due to the softening agent or the like contained therein, and producible relatively at low cost in a simple production process, and to provide a development apparatus using the above roller. SOLUTION: The objective electroconductive thermoplastic elastomer composition comprises (A) a polyamide-based elastomer, (B) an oil-extended olefin-based copolymer rubber comprising 100 pts. mass of an olefin-based copolymer rubber with a 100 deg.C Mooney viscosity (ML1+4 100 deg.C) of 120-350 and 20-150 pts. mass of a mineral oil-based softening agent, (C) a modified polyolefin resin and (D) an electroconductive filler; wherein this elastomer composition is characterized by that the component A constitutes the matrix phase, while the component B constitutes the dispersed phase, and the component D is present selectively in the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive thermoplastic elastomer composition, a developing roller using the same in an electrophotographic apparatus such as a copying machine or a printer, or an electrostatic recording apparatus, and a developing apparatus using the same. .

[0002]

2. Description of the Related Art In recent years, thermoplastic elastomers, which are rubber-like soft materials that do not require a crosslinking step and are easy to recycle, have been attracting attention. Widely used in the fields of medical parts, daily necessities, etc.

[0003] These thermoplastic elastomers have a soft rubber-like feel, and have better moldability, weatherability,
It has excellent colorability and the like, and has been widely used in terms of cost.

In recent years, with the progress of electrophotographic technology, demands for conductive members used in various electrophotographic processes have been increasing, and in particular, a developing roller used in a developing device has attracted attention. The characteristics required for such a developing roller are not only a predetermined electric resistance value, but also various developing mechanisms such as low hardness, low compression set, and no surface contamination due to bleeding of a softener and the like. It is necessary to add characteristics suitable for

[0005] Here, if a large amount of a softening agent such as oil is blended in order to lower the hardness, bleeding to the surface of the molded article becomes a problem, and the blending amount of the softening agent and the like is limited. In addition, in the method of forming foamed voids in a molded body using a chemical foaming agent, a high-pressure gas, or the like, problems such as variations in bubble size and communication of bubbles occur. Has become one of the causes of worsening.

[0006] Development methods in electrophotography are mainly classified into a one-component development method and a two-component development method.
In recent years, since it is necessary to reduce the size of a copying apparatus for the purpose of reducing the weight and size of an electrophotographic apparatus, a developing apparatus using a one-component toner is often used.

For example, a one-component developer (hereinafter, referred to as a toner) is carried on a developing roller as a developer carrier,
A contact development method is known in which a toner is transferred from a developing roller to the surface of the photosensitive drum by bringing the toner into contact with the photosensitive drum, and the electrostatic latent image is visualized as a toner image. According to this method,
Since no magnetic material is required, the device can be easily simplified and downsized, and the toner can be easily colored.

In the contact developing method, a developing roller carrying toner is brought into contact with an electrostatic holding member such as a photosensitive drum holding an electrostatic latent image, and the toner is attached to the latent image on the electrostatic holding member. In order to perform development, the developing roller needs to be formed of a conductive elastic body.

That is, in this contact developing method, as shown in FIG. 3, for example, a developing container containing toner 6 is rotated in a direction indicated by an arrow a in FIG. Developing roller 3 opposed to photosensitive drum 1
And develops the electrostatic latent image on the photosensitive drum 1 to visualize it as a toner image. The developing roller 3 is driven to rotate in the direction of arrow b with respect to the rotation direction a of the photosensitive drum 1.

Further, in the developing container 2, a developing blade 4 is provided above the developing roller 3, and an elastic roller 5 is provided at a position upstream of the developing blade 4 in the rotation direction of the developing roller 3.

In the developing device, the elastic roller 5 rotates in the direction of arrow c, and carries the toner 6 by the rotation of the elastic roller 5 to supply the toner 6 to the vicinity of the developing roller 3. 5 adheres onto the developing roller 3 by being rubbed at a contact portion (nip portion) where the contact member 5 contacts.

Thereafter, with the rotation of the developing roller 3, the toner 6 adhering to the developing roller 3 is rubbed at the contact portion between the developing blade 4 and the developing roller 3, and is sufficiently subjected to triboelectric charging to form a thin layer. And transported to the photosensitive drum 1. In the developing section, an alternating voltage obtained by superimposing DC and AC is applied as a developing bias between the developing roller 3 and the photosensitive drum 1 so that the toner 6 on the developing roller 3 The image is transferred corresponding to the image, adheres to the electrostatic latent image, is developed, and is visualized as a toner image.

The toner 6 remaining without being consumed by the developing unit in the developing unit is transferred to the developing roller 3 together with the rotation of the developing roller 3.
From the lower part of the developing container 2.

On the other hand, most of the stripped toner 6 is conveyed and mixed into the toner 6 in the developing container 2 with the rotation of the elastic roller 5, and the stripped toner 6 is removed.
Is dispersed.

Here, as proposed in JP-A-05-59206 and JP-A-07-329214, the developing roller 3 has to rotate while reliably maintaining the state in which it is in close contact with the photosensitive drum 1. For this purpose, as shown in FIG. 2, a conductive elastic layer made of a low-hardness conductive rubber composition or a foam layer 3c (base layer) made of a conductive foam is formed on the outer periphery of the cored bar 2. Further, a structure is known in which a resin coating layer 3d (surface layer) in which at least a plurality of layers of a conductive agent is blended is formed.

[0016]

However, the conventional developing roller has the following disadvantages.

1) Since the conventional conductive elastic layer and conductive foam layer are formed from a normal rubber composition, a vulcanization step of heating the rubber composition for a long time is essential. And control becomes difficult.

2) In addition, since a three-dimensional network structure is formed by vulcanization, the material cannot be recycled and is not environmentally friendly.

Further, when a foamed molded product is obtained, 3) since a chemical foaming agent or the like is used, the cell size varies, and the non-uniform cell size deteriorates the compression set characteristic.

In the case where two or more conductive resin coating layers are formed on the surface of the base layer, 1) the production process becomes complicated because of the multilayer structure, and inexpensive rollers and developing devices cannot be supplied. .

2) Generally, when a conductive filler is simply mixed with a thermoplastic resin or a thermoplastic elastomer,
Extremely high hardness occurs, and the material tends to be brittle in physical properties, causing a problem in durability. It can be used if it can be thinned to the extent that it can be elastically deformed. However, there is a limit to thinning, and it is difficult to obtain a sufficiently uniform nip with the photosensitive drum.

3) It is not environmentally friendly because there are many steps using a solvent such as coating.

An object of the present invention is to provide a conductive thermoplastic elastomer composition which does not have the above-mentioned disadvantages.

The present invention uses a conductive thermoplastic elastomer composition and has a JIS A in the range of 15 to 60, particularly 15
~ 50 is preferred. If the hardness is 60 degrees or less, a sufficient nip width is obtained, and if it is 15 degrees or more, the compression set and the like are good. Alternatively, using the thermally expanded hollow particles (E),
When the hardness is reduced, the Asker C hardness is preferably in the range of 15 to 50.

A developing roller and a developing roller which have low compression set (preferably as small as possible, specifically 20% or less), have no surface bleed due to a softening agent and the like, and can be manufactured at a relatively low cost by a simple manufacturing process. It is intended to provide a device.

[0026]

The present application is constituted by the following inventions.

(1) Polyamide-based elastomer (A) having a Mooney viscosity at 100 ° C. (ML _{1 + 4} 100 ° C.) of 12
Oil-extended olefin-based copolymer rubber (B), modified polyolefin resin (C), conductive filler containing 20 to 150 parts by mass of a mineral oil-based softener per 100 parts by mass of olefin-based copolymer rubber of 0 to 350 (D)
(A) / ((B) + (C)) = 70-15 / 30-85 parts by mass, based on 100 parts by mass of (A) + (B) + (C)
(D) is 1 to 30 parts by mass, (A) is a matrix phase,
A conductive thermoplastic elastomer composition, wherein the component (B) forms a dispersed phase, and the component (D) is selectively present in the component (A).

(2) (A), (B), (C) and a crosslinking agent,
(1) The conductive thermoplastic elastomer composition according to (1), which has a step of kneading an additive selected from a softening agent and the like and subjecting (B) to a crosslinking reaction under shearing force during melting of (A).

(3) The conductive thermoplastic elastomer composition according to any one of (1) and (2), wherein the addition of (D) is performed after the completion of the crosslinking reaction of (B).

(4) The olefin copolymer rubber is an ethylene-propylene-non-conjugated diene rubber (1)-
The conductive thermoplastic elastomer composition according to any of (3).

(5) The ethylene-propylene-nonconjugated diene rubber has a propylene content of 10 to 55% by mass,
The conductive thermoplastic elastomer composition according to any one of (1) to (4), which is an ethylene-propylene-ethylidene norbornene copolymer rubber having an ethylidene norbornene content of 1 to 30% by mass.

(6) 100 ° C. Mooney viscosity (ML _{1 + 4} 100 ° C.) of the oil-extended olefin copolymer rubber (B) is 30.
The conductive thermoplastic elastomer composition according to any one of (1) to (5), wherein

(7) Polyamide-based elastomer (A)
Is a block copolymer of a polyamide and a polyether, and the polyamide content is 20 to 80% by mass, the conductive thermoplastic elastomer composition according to any one of (1) to (6).

(8) The thermoplastic elastomer composition has a hardness (JIS A) of 15 to 50 degrees (1) to (7).
The conductive thermoplastic elastomer composition according to any one of the above.

(9) Further, 1 to 30 parts by mass of the thermally expandable hollow particle (E) component is added (1).
The conductive thermoplastic elastomer composition according to any one of (1) to (8).

(10) The thermally expanded hollow particles (E) are
A foam elastic roller obtained by dry-blending the composition of any one of (1) to (8) before molding and foam-molding the composition.

(11) The conductive thermoplastic elastomer composition according to (9), wherein the thermoplastic elastomer composition has a hardness (Asker C) of 15 to 50 degrees.

(12) An elastic roller using the conductive thermoplastic elastomer composition according to any one of (1) to (8) as a developing roller.

(13) A developing device having a developer accommodating container for accommodating a one-component developer and a developing roller for carrying and transporting the developer from the container to a developing section, wherein the developing roller is an elastic roller according to (12). A developing device, characterized in that:

(14) In a process cartridge in which at least the electrophotographic photosensitive member and the developing device are integrally formed as a cartridge and which is detachable from the main body of the image forming apparatus, the developing value of the developer is a one-component developer. In a developing device having a storage container and a developing roller for carrying and transporting a developer from the container to a developing unit, the developing roller may be configured as (1)
A developing device comprising the elastic roller according to 3).

(15) In a developing device having a developer accommodating container for accommodating a one-component developer, and a developing roller for carrying and transporting the developer from the container to a developing section, the elastic foam roller described in the developing roller (10) may be used. A developing device.

(16) In a process cartridge in which at least the electrophotographic photosensitive member and the developing device are integrally formed as a cartridge and which is detachable from the main body of the image forming apparatus, the developing value is a developer containing a one-component developer. In a developing device having a storage container and a developing roller for carrying and transporting a developer from the container to a developing unit, the developing roller may be configured as (1)
A developing device, which is the elastic foam roller according to item (1).

(17) A method in which a roller selected from the elastic roller or the elastic foaming roller according to (10) or (12) is used to recover the conductive thermoplastic elastomer composition from a used device and regenerate the roller.

[0044]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive studies to achieve the above object, the present inventor has found that a developing roller having a conductive plastic elastomer composition on the outer periphery of a cored bar can be used with an existing extruder or injection molding. It is characterized by molding or foam molding by extrusion molding or injection molding using equipment such as a machine, low hardness, low compression set, no surface bleed due to softener, etc., stable resistance as a whole roller This completes a developing roller that can be controlled and that can be manufactured at a relatively low cost by a simple manufacturing process.

According to the present invention, a non-magnetic one-component toner is carried on a developing roller formed by molding or foaming the above-mentioned conductive thermoplastic elastomer composition on the outer periphery of a core metal, and a thin layer of the toner is formed. In this state, the developer contacts the latent image holding member holding the electrostatic latent image on the surface, and causes the developer to adhere to the electrostatic latent image on the surface of the latent image holding member from the thin layer, thereby visualizing the electrostatic latent image. A developing roller characterized in that the main component is the foamed conductive thermoplastic elastomer composition, and a roller-like or drum-like latent image holding member that holds an electrostatic latent image on the surface. Abuts on the surface of the latent image holding member with the non-magnetic one-component toner carried on the outer peripheral surface,
A developing roller for rotating the latent image holding member in association with the rotational movement thereof to cause the non-magnetic one-component toner to adhere to the electrostatic latent image on the surface of the latent image holding member and to visualize the electrostatic latent image; There is provided a developing device comprising the above-mentioned developing roller.

Hereinafter, the present invention will be described in more detail. As shown in FIG. 1, the developing roller of the present invention
Is formed by molding or foaming the conductive thermoplastic elastomer composition 3b on the outer periphery.

Here, as the metal core 2, any material having good conductivity can be used.

Next, the conductive thermoplastic elastomer composition 3b will be described. The conductive thermoplastic elastomer composition of the present invention comprises a polyamide elastomer (A),
100 ° C Mooney viscosity (ML _{1 + 4} 100 ° C) is 120-3
Oil-extended olefin copolymer rubber (B), modified polyolefin resin (C), conductive filler (D) containing 20 to 150 parts by mass of a mineral oil-based softener per 100 parts by mass of olefin copolymer rubber of 50 ) Component, or a thermally expandable hollow particle (E) component added thereto, and (A) / ((B) + (C)) = 70-15 / 30-85 parts by mass, (A) + (B) + (C) 100 parts by mass, (D)
Is 1 to 30 parts by mass, or 1 to 30 parts by mass of (E), and the oil-extended olefin copolymer rubber (B) is an organic peroxide under shearing force when the polyamide elastomer (A) is melted. The polyamide-based elastomer (A) forms a matrix phase, the oil-extended olefin-based copolymer rubber (B) component forms a dispersed phase, and the conductive filler (D) comprises (A) Characterized by being selectively present therein.

As the polyamide elastomer (A) used in the present invention, a known thermoplastic elastomer comprising a hard segment and a soft segment is used, and a hard segment such as nylon 6, 66, 11, or 12 and a polyether or polyester are used. It is a block copolymer containing soft segments such as components.

The polyamide which is a hard segment includes, for example, terephthalic acid, isophthalic acid, oxalic acid, adipic acid, sebacic acid, 1,4-cyclohexyldicarboxylic acid, a dimerized fatty acid having 36 carbon atoms, or a dimerized fatty acid having the same as a main component. Polycondensates of dicarboxylic acids such as mixtures of polymerized fatty acids with ethylenediamine, pentamethylenediamine, hexamethylenediamine, hexamethylenediamine, 1,4-cyclohexyldiamine, m-xylyldiamine, or caprolactam, lauryl Examples include ring-opening polymers of lactams such as lactams, polycondensates of aminocarboxylic acids such as aminononanoic acid and aminoundecanoic acid, and those obtained by copolymerization of the above-mentioned cyclic lactams, dicarboxylic acids and diamines.

Examples of the polyester serving as a soft segment include aliphatic glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and 1,4-bis (hydroxymethyl) -cyclohexane. Or those obtained from one or more alicyclic diols and the above-mentioned dicarboxylic acids, polycondensates of lactone compounds such as poly-ε-caprolactone, etc., and having a hydroxyl group or a carboxyl group at the terminal It is.

Examples of the polyether serving as the soft segment include polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, and copolymers thereof.

The olefin copolymer rubber used in the oil-extended olefin copolymer rubber (B) used in the present invention is, for example, ethylene-propylene copolymer rubber,
It is an amorphous random elastic copolymer containing an olefin as a main component, such as an ethylene-propylene-non-conjugated diene rubber, an ethylene-butene-non-conjugated diene rubber, and a propylene-butadiene copolymer rubber. Among these, an ethylene-propylene-non-conjugated diene rubber is particularly preferred. Non-conjugated dienes include dicyclopentadiene, 1,
There are 4-hexadiene, cyclooctadiene, methylenenorbornene, ethylidene norbornene and the like, with ethylidene norbornene being particularly preferred.

As a more preferred specific example, the propylene content is 10 to 55% by mass, preferably 20 to 40% by mass.
Ethylene-propylene-ethylidene norbornene copolymer rubber having a non-conjugated diene content of 1 to 30% by mass, preferably 3 to 20% by mass such as ethylidene norbornene (hereinafter also referred to as other non-conjugated diene) "EP
DM ". ) And its 100 ° C Mooney viscosity (ML _{1 + 4} 100 ° C) is 120 to 350, preferably 1
40-300. When the propylene content is 10% by mass or more, flexibility is obtained, and when the propylene content is 55% by mass or less, mechanical properties are maintained.

If the non-conjugated diene content represented by ethylidene norbornene is more than 1%, the mechanical properties are good,
When the content is 30% by mass or less, the injection moldability is good. 100 ℃
If the Mooney viscosity (ML _{1 + 4} 100 ° C.) is lower than 120, the mechanical properties are lowered, and if it is higher than 350, the appearance of the molded article is impaired. However, Mooney viscosity is 120-350
When EPDM is used, the mechanical properties are large, the tensile strength at break and the elongation at break are remarkably improved, and the crosslinking efficiency is increased, whereby the mechanical properties, particularly the strength and the compression set are improved. EPDM manufactured by a known method can be used.

The mineral oil-based softener used in the present invention is a high-boiling oil fraction incorporated for the purpose of improving processability and mechanical properties, and is a paraffinic, naphthenic or aromatic oil fraction. Although there is a group system or the like, a paraffin system is preferably used. When the amount of the aromatic component is large, the contamination becomes strong, and there is a limit in the use intended for a transparent product or a bright color product, which is not preferable.

The oil-extended olefin copolymer rubber (B) is
20 to 150 parts by mass, preferably 30 to 120 parts by mass of a mineral oil-based softener per 100 parts by mass of the olefin-based copolymer rubber.
It is contained by mass. If the amount is less than 20 parts by mass, the fluidity of the thermoplastic elastomer composition is reduced, and particularly, the extrusion processability and the injection moldability are impaired. On the other hand, when the amount is more than 150 parts by mass, the plasticity is remarkably increased and the processability is deteriorated, and furthermore, the performance such as the physical properties of the product is undesirably reduced. And oil-extended olefin copolymer rubber (B)
Has a Mooney viscosity (ML _{1 + 4} 100 ° C.) of preferably 30 to 100, more preferably 40 to 90.
If it is 30 or more, the mechanical properties are good, and if it is 100 or less, the molding process is good.

When a large amount of a mineral oil-based softening agent is blended with EPDM having a Mooney viscosity of 120 to 350, it is possible to simultaneously satisfy the requirements for securing flexibility, improving workability by improving fluidity, and improving mechanical properties. Can be obtained. Generally olefin-based TPE
(Thermoplastic elastomer) The composition uses a mineral oil-based softener as a flow improver. According to the research of this researcher, when oil-extended EPDM is not used, the viscosity of EPDM is reduced. Regardless, 4 mineral oil softeners per 100 parts by mass of EPDM
If it is added in an amount of 0 parts by mass or more, bleeding of the softening agent occurs on the surface of the thermoplastic elastomer composition, and contamination and adhesion of the product are not preferred. However, 100 ° C. Mooney viscosity is 120 to 350.
Oil-extended EPDM premixed with 150 parts by weight of mineral oil-based softener
By using, a conductive thermoplastic elastomer composition having no bleeding of the softening agent, no contamination or sticking of the product, and having excellent physical properties such as breaking strength, breaking elongation and compression set can be obtained. Despite the large blending ratio of this mineral oil-based softening agent, no bleeding of the softening agent is observed because the use of EPDM with a high Mooney viscosity raises the upper limit of the allowable oil spreading amount of the mineral oil-based softening agent This is considered to be because a softener suitably added in advance is uniformly dispersed in EPDM.

In order to improve the compatibility between (A) and (B), a modified polyolefin resin (C) is used as a compatibilizer. This is thought to be caused by the reaction with the polyamide-based elastomer (A) that forms the matrix phase during kneading to form a graft polymer. However, by lowering the interfacial tension at the (A) / (B) interface, the dispersed particles are reduced. It is thought that the mechanical properties can be improved by reducing the diameter and reinforcing the interface.

The modified polyolefin resin (C) used as a raw material of the compatibilizer at this time is obtained by graft copolymerizing an unsaturated carboxylic acid or a derivative thereof to a base polyolefin resin. As the unsaturated carboxylic acid or derivative thereof used in the present invention,
For example, unsaturated dicarboxylic acids such as acrylic acid, methacrylic acid, maleic acid and fumaric acid and derivatives thereof such as acid halides, amides, imides, acid anhydrides and esters are mentioned. Among these, maleic acid and nadic Acids or acid anhydrides thereof are preferably used. As a method of graft-copolymerizing an unsaturated carboxylic acid or a derivative thereof to a polyolefin resin serving as a base of the modified polyolefin resin, various known methods can be used. A method of adding a carboxylic acid or a derivative thereof and a polymerization initiator such as an organic peroxide, an organic perester, or an azo compound and melt-kneading and copolymerizing the solution, or a method of dissolving in a solvent and copolymerizing by heating reaction can be mentioned. Such a modified polyolefin is available as a commercial product, and examples thereof include Bondyne (trade name, manufactured by Sumika Atochem Co., Ltd.).

The modified polyolefin containing an epoxy group in the molecule is not particularly limited, and is a commercially available one, and may be a copolymer of ethylene and glycidyl methacrylate or ethylene-acrylic acid, ethylene-methacrylic acid. Examples include a terpolymer of acid, ethylene acrylate, ethylene methacrylate, or the like and glycidyl methacrylate, and PP grafted with glycidyl methacrylate.

The amount of component (C) added is preferably (A)
1 to 20% by mass, more preferably 1 to 10% by mass.

The peroxide used for the crosslinking reaction of the oil-extended olefin copolymer rubber (B) is not particularly limited. For example, benzoyl peroxide, p-chlorobenzoyl peroxide, azobisisobutyronitrile, 2,5-dimethyl-
2,5-di (t-butylperoxy) hexyne, 2,5-
Dimethyl-2,5 di (benzoylperoxy) hexane, 2,2'-bis (t-butylperoxy) -p-diisopropylbenzene, 1,1-bis (t-butylperoxy) -3,3,5- Trimethylcyclohexane, 3,5,5
-Trimethylhexanoyl peroxide, 2,4-dichlorobenzoyl peroxide, cyclohexanone peroxide, t-butylperoxybenzoate, dicumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, cumene hydro Peroxides and the like are found.

The amount of the organic peroxide to be used is as follows:
The amount is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass per 0 parts by mass. If the amount is too small, the crosslinking density is low, and the rubber elasticity becomes insufficient.
If the amount is too large, inconvenience such as foaming may occur during vulcanization molding, which is not preferable.

In the present invention, in order to improve the crosslinking efficiency at the time of vulcanization with an organic peroxide, a known crosslinking aid, p,
p'-dibenzoylquinone dioxime, quinone dioxime, triallyl cyanurate, sulfur, ethylene dimethacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, N, N'-m-phenylenebis Maleimide, triallyl isocyanurate, trimethylolpropane trimethacrylate and the like may be used. The amount can be selected from the range of 0.01 to 5.0 parts by mass. By the incorporation of such a compound, a uniform and mild cross-linking reaction occurs, and the mechanical properties can be improved. If the amount is less than 0.01 mass, the effect hardly appears, and 5.
If it exceeds 0 mass, it is not economically advantageous.

The degree of cross-linking of the oil-extended olefin copolymer rubber (B) varies greatly depending on the position and method of adding a cross-linking agent, and the composition of the present invention has a completely cross-linked type having almost no uncross-linked components. Although it is roughly classified into a partially crosslinked type in which a crosslinked portion exists, a fully crosslinked type having almost no uncrosslinked portion is preferable in order to exhibit more crosslinked rubber properties.

Next, the conductive filler (D) used in the present invention includes EC (Extra Conductive) and ECF (Extra Condu
ctive Furnace), SCF (Super Conductive Furnace), CF
(Conductive Furnace), acetylene black, etc. (including Ketjen Black EC [brand name].), SAF (Super Abr
asion Furnace), ISAF (Intermediate SAF), HAF (High
Abrasion Furnace), FEF (Fast Extruding Furnace),
GPF (General Purpose Furnace), SRF (Semi Reinforcin)
g Furnace), FT (Fine Furnace), MT (MediumThermal)
Carbon blacks such as Al-doped ZnO, SnO ₂ (antimony oxide doped), TiO ₂ , SnO ₂ (antimony oxide-doped), SnO ₂ , SnO ₂ TiO ₂ , K ₂ O · nTiO ₂ / SnO ₂ Sb ₂ O ₅ ,
Metal oxides such as SnO ₂ (antimony oxide-doped) complex oxides; and simple metals such as copper powder, silver powder, and aluminum powder can be described. Among them, carbon black which is inexpensive and easy to control the dielectric properties in a small amount is carbon black. Usually, the component (D) is suitably used in an amount of 1 to 30 parts by mass, particularly preferably 1 to 15 parts by mass based on 100 parts by mass of (A) + (B) + (C).

Although the conductive thermoplastic elastomer composition of the present invention is not particularly limited, the resistance value of the conductive thermoplastic elastomer composition is set to 10 ³ Ω · 10 ¹⁰ Ω · by adding the conductive filler (D), for example, carbon black. cm is preferred.

Further, it is possible to eliminate unevenness in electric
Conductive fillers to reduce unit-to-unit variation
And the electrical resistivity is 10⁰Ω · cm or less, preferably 5 ×
10^{- 1}Ω · cm or less and electric resistivity of 10¹-10^Ten
Ω · cm, preferably 10¹-10^FiveCombined with Ωcm
It is preferable to use them together.

In order to obtain the conductive thermoplastic elastomer resin composition of the present invention, the polyamide elastomer (A)
Heating the oil-extended olefin-based copolymer rubber (B) above the melting point of (A) and applying sufficient shearing force during melting to crosslink the oil-extended olefin-based copolymer rubber (B) It is preferable to manufacture by the method containing. This method is a method called dynamic crosslinking, and by using this method, the mechanical properties of the composition of the present invention are dramatically improved. The apparatus used at this time is not particularly limited, and a roll-type kneader, a kneader or the like, or a screw extruder, a continuous kneader such as a rotor-type continuous kneader, or the like may be used alone or in combination. Can be Particularly, a twin-screw kneader is preferable.

As the addition position of the conductive filler (D),
It is better to add it after the completion of the crosslinking reaction (B). this is,
This is for selectively dispersing in (A). Early (A)
When a mixture obtained by dry blending of / (B) / (C) / (D) is added, the target electric resistance cannot be obtained because the conductive filler (D) is dispersed in (B). By selectively being present in (A), a desired function can be exhibited with a small amount of (D) added. In particular, the increase in hardness due to the addition of the conductive filler is represented by the ratio of (A) / ((B) + (C)), particularly (B)
The higher the ratio, the lower the hardness of the conductive thermoplastic elastomer composition, the finely dispersed crosslinked structure of (B) greatly contributes to flexibility and recovery of deformation, and reduces compression strain, which is a drawback of the thermoplastic elastomer. .

As the heat-expandable hollow particles (E) which can be optionally added in the present invention, for example, foams represented by heat-expandable microcapsules of Matsumoto Yushi Seiyaku Co., Ltd. introduced in 1990, Vol. Show the material. These are fine particles of about several tens of μm in which a low boiling organic solvent such as isobutane / pentane is contained in a thermoplastic resin capsule made of viridinene chloride / acrylonitrile / acrylate / methacrylate. Upon heating, the thermoplastic resin capsule is softened and, at the same time, the internal organic solvent is vaporized and expanded to form expanded particles 50 to 100 times in volume. Products with an optimal foaming temperature of 100-200 ° C. are available. The thermally expanded hollow particles (E) need only have the above functions, and are not limited to those exemplified.

It is necessary to adjust the amount of the thermally expanded hollow particles (E) according to the required expansion ratio. The amount is 1 to 30 parts by mass, preferably 2 to 20 parts by mass, per 100 parts by mass of (A) + (B) + (C). If it is less than 1 part by mass, it does not contribute to a predetermined expansion ratio or hardness reduction, and if it is more than 30 parts by mass, the mechanical strength of the material is lowered, or it is not economically effective.

The addition of the heat-expandable hollow particles (E) is preferably carried out by dry blending with pellets of the conductive thermoplastic elastomer composition and molding by extrusion or injection molding before roller molding. This is to avoid unnecessary heating and excessive temperature setting in consideration of the properties of the thermally expanded hollow particles in roller molding. Since the heat-expandable hollow particles shrink or burst when heated even after expansion, it is preferable to set equipment and conditions to avoid excessive pressure and stagnation in the molding machine.

The developing roller of the present invention can be incorporated in a normal developing device using a non-magnetic one-component developer, and more specifically, as shown in FIG. The developing roller 3 of the present invention is disposed between the photosensitive drum 1 holding the latent image in contact with the photosensitive drum 1, and the toner 6 is supplied to the developing roller 3 by the elastic roller 5, and is developed. A uniform thin layer is prepared by the blade 4, and toner is supplied from the thin layer to the photosensitive drum 1, and the toner is adhered to the electrostatic latent image on the photosensitive drum 1 to visualize the latent image. Note that the details of FIG. 3 have been described in the related art, and thus description thereof will be omitted.

Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[0077]

Examples [Example 1-1] Table 1 shows the composition. As a pretreatment, a 5 mm × 5 mm × 5 mm square pelletized oil-extended olefin copolymer rubber (trade name: Esplen 600F: ethylene content 70% by mass ML _{1 + 4} 100 ° C .: 53, oil extension 1)
36.0 parts by mass of 00 phr (manufactured by Sumitomo Chemical Co., Ltd.), 0.4 parts by mass of stearic acid, 0.4 parts by mass of an antioxidant (trade name: Irganox 1010, manufactured by Ciba Geigy), a crosslinking aid (Trade name: NF Weinmer ethylene glycol dimethacrylate (Daiichi Kogyo Seiyaku Co., Ltd.)) 1.2
Parts by mass, a crosslinking agent (2,5-dimethyl-2,5-di (t-butylperoxy) hexyne (manufactured by NOF Corporation) 0.8
Parts by mass, 4.0 parts by mass of a maleic anhydride-modified polyolefin (trade name: Bondine AX8030 (manufactured by Sumika Atochem))
Polyamide-based elastomer (trade name: PEBAX2533 (manufactured by Toray Industries, Inc.): The structure is a polyamide-based elastomer having the following chemical structure (Formula 1)): 60.0% by mass

[0078]

Embedded image

Was uniformly blended for 10 minutes using a Henschel mixer. This blend was subjected to a dynamic heat treatment at 185 ° C. for 150 seconds using a twin-screw kneader,
A thermoplastic elastomer composition was obtained.

Further, 10.0 parts by mass of a conductive filler (trade name: Ketjen Black EC (manufactured by Mitsubishi Chemical)) was uniformly blended with 100 parts by mass of the thermoplastic elastomer composition using a Henschel mixer for 10 minutes. Was.
Using a single-screw extruder equipped with a crosshead, simultaneously extrude the core metal coated with the adhesive layer onto a tube at 200 ° C., and extrude the tube to a thickness of 4.0 mm, an outer diameter of 16 mm, and a length of 220 mm.
Was formed to obtain a developing roller.

[Hardness] A disc piece having a diameter of 29 mm and a thickness of 12.5 mm was used at 23 ° C. × 50% in accordance with JIS K6301.
It was measured under the condition of RH. The measurement result was 45 degrees according to JIS A.

[Compression permanent set] Diameter 29 mm, thickness 12.
5mm disc pieces are compressed 25% at 40 ° C for 72 hours,
Next, the sample was left standing in an atmosphere of 23 ° C. × 50% RH for 24 hours, and then measured in accordance with JIS K6301. The measurement result was 17.

[Roller resistance]
A voltage of 0 V was applied, and the electric resistance of the roller was measured with a predetermined electric resistance meter. The measurement result was 3.5 × 10 ⁵ Ω · cm.

[Drum Contamination Property]
A load of 500 g was applied to each of the shaft main bodies at both ends, pressed against a new photosensitive drum, and left for one month in a greenhouse environment of 40 ° C. × 95% RH. The photoreceptor was observed, and the case where no roll mark was observed was evaluated as ○, and the case where it was observed was evaluated as x. As a result of the measurement, no contamination of the photoreceptor was observed.

[Image Output] The prepared developing roller was mounted on a developing unit, containing a non-magnetic one-component toner at 15 ° C.
Under a low-temperature and low-humidity environment of 10%, when an image was output up to 6000 sheets using a laser beam printer (trade name: Lasershot: manufactured by Canon), the initial image state was compared. When the image was displayed, there was no problem at all.

[Examples 1-2 to 1-4] In preparing a conductive thermoplastic elastomer composition, molding and measurement were conducted in the same manner as in Example 1 except that the mixing ratio as shown in Table 1 was changed. . There were no problems with roller resistance, drum contamination, and image output.

[0087]

[Table 1]

Comparative Example 1-1 A conductive thermoplastic elastomer composition was molded and measured in the same manner as in Example 1-1, except that the mixing ratio as shown in Table 2 was changed.
As a result, the hardness was 60 and the compression set was 35. For this reason, even in image formation, uniform contact with the photosensitive drum could not be obtained, and a stable nip could not be formed, resulting in density unevenness.

[Comparative Example 1-2] Same as Example 1-1 except that the amount of peroxide as a crosslinking agent as shown in Table 2 was changed when preparing a conductive thermoplastic elastomer composition. And molded. As a result, the hardness became 40,
The compression set became 28 and worse. For this reason, distortion deformation remains in the contact portion with the photosensitive drum, thereby reducing the contact property. As a result, white spots occur in the image.

[Comparative Example 1-3] When a conductive thermoplastic elastomer composition was prepared, a conductive filler and thermally expanded hollow particles were simply added to a polyamide-based elastomer as shown in Table 2. Molding and measurement were performed in the same manner as described above. As a result, the hardness was 95 and the compression set was 56. For this reason, even in image formation, uniform contact with the photosensitive drum could not be obtained, and a stable nip could not be formed, resulting in density unevenness.

[Comparative Example 1-4] In preparing a conductive thermoplastic elastomer composition, as shown in Table 2, instead of a polyamide-based elastomer, a PVC-based elastomer (Sunplane F1469, manufactured by Mitsubishi Kasei Vinyl Co., Ltd.) was used. Molding and measurement were carried out in the same manner as in Example 1 except for using. As a result, the hardness was 25 and the compression set was 14. In the contamination test,
The plasticizer added to the PVC-based elastomer migrated to the surface of the photosensitive drum, and the surface deteriorated, leaving traces. Even when an image was displayed, the toner adhered and solidified.

[0092]

[Table 2]

Example 2-1 Table 1 shows the composition. As pretreatment, 36.0 parts by mass of an oil-extended olefin copolymer rubber (trade name: Esplen 600F (manufactured by Sumitomo Chemical Co., Ltd.)) was pelletized into 5 mm × 5 mm × 5 mm square pellets and stearic acid was added to 0.4 part by mass.
Parts by mass, an antioxidant (trade name Irganox 1010,
0.4 parts by mass (manufactured by Ciba Geigy), 1.2 parts by mass of a crosslinking assistant (trade name: NF Beinmer ethylene glycol dimethacrylate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)), a crosslinking agent (2,
0.8 parts by mass of 5-dimethyl-2,5-di (t-butylperoxy) hexine (manufactured by NOF Corporation), maleic anhydride-modified polyolefin (trade name: Bondyne AX8030)
4.0 parts by mass (manufactured by Sumika Atchem), polyamide-based elastomer (trade name: PEBAX2533 (manufactured by Toray Industries, Inc.))
A uniform blending operation of 0 mass% was performed for 10 minutes using a Henschel mixer. This blend was subjected to a dynamic heat treatment at 185 ° C. for 150 seconds using a twin-screw kneader to obtain a thermoplastic elastomer composition.

Further, 10.0 parts by mass of a conductive filler (trade name of Ketjen Black EC (manufactured by Mitsubishi Chemical)), 100 parts by mass of the thermoplastic elastomer composition, and heat-expandable hollow particles (trade name of Matsumoto Microsphere) F-100
A uniform blending operation of 12.0 parts by mass (trade name: manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was performed for 10 minutes using a Henschel mixer. Using a single-screw extruder equipped with a crosshead, extrude the tube onto the tube at 200 ° C while simultaneously inserting the core metal coated with the adhesive layer. The tube has a thickness of 4.0 mm, an outer diameter of 16 mm, and a length of 220 mm. Was formed to obtain a developing roller.

The composition obtained was measured according to the method described in Example 1-1. The hardness was 45 degrees as Asker C, the compression set was 19, the roller resistance was 3.5 × 10 ⁵ Ω · cm, the drum contamination was ○, and there was no problem in image output.

[Examples 2-2 to 2-4] When preparing a conductive thermoplastic elastomer composition, molding was carried out in the same manner as in Example 2-1 except that the mixing ratio as shown in Table 3 was changed. It was measured. However, regarding the addition of paraffin oil,
Using a liquid addition pump, the mixture was continuously and quantitatively injected so as to have the composition shown in Table 1. There were no problems with the twin-screw extruder roller resistance, drum contamination, and image output.

[0097]

[Table 3]

Comparative Example 2-1 A conductive thermoplastic elastomer composition was molded and measured in the same manner as in Example 2-1 except that the compounding ratio shown in Table 4 was changed.
As a result, the hardness was 55 and the compression set was 38. For this reason, even in image formation, uniform contact with the photosensitive drum could not be obtained, and a stable nip could not be formed, resulting in density unevenness.

[Comparative Example 2-2] In the same manner as in Example 2-1 except that the amount of peroxide as a crosslinking agent as shown in Table 4 was changed when preparing a conductive thermoplastic elastomer composition. And molded. As a result, the hardness became 40,
The compression set was 35, which was worse. For this reason, distortion deformation remains at the contact portion with the photosensitive drum, thereby reducing the contact property, and as a result, white spots occur in the image.

[Comparative Example 2-3] In preparing a conductive thermoplastic elastomer composition, a conductive filler and thermally expanded hollow particles were simply added to a polyamide-based elastomer as shown in Table 4. Molding and measurement were performed in the same manner as described above. As a result, the hardness was 76 and the compression set was 63. For this reason, even in image formation, uniform contact with the photosensitive drum could not be obtained, and a stable nip could not be formed, resulting in density unevenness.

[Comparative Example 2-4] In preparing a conductive thermoplastic elastomer composition, a non-oil-extended EPDM (trade name: 501A, manufactured by Sumitomo Chemical Co., Ltd.) was used instead of the oil-extended EPDM used in the examples.
Was molded and measured in the same manner as in Example 2-1 using the composition shown in Table 2. As a result, the hardness was 40, but the compression set was 3
It was 4. With the same composition, oil bleed occurs, contaminates the drum surface, and even when an image is displayed, uniform contact with the photosensitive drum cannot be obtained due to a decrease in compression set, and a stable nip cannot be formed. occured.

[Comparative Example 2-5] When preparing a conductive thermoplastic elastomer composition, a chemical blowing agent azodicarbonamide (trade name: CellMike CAP-500 (Sankyo Chemical Co., Ltd.)
Was used and molded in the same manner as in Example 2-1 with the composition shown in Table 2, and as a result of measurement, the hardness was 40 and the compression set was 35.
It became. For this reason, distortion deformation remains in the contact portion with the photosensitive drum, thereby reducing the contact property. As a result, white spots occur in the image.

[0103]

[Table 4]

[0104]

As described above, the present invention reduces the hardness by using the conductive thermoplastic elastomer composition.
It is possible to provide a developing roller and a developing device which can be manufactured at a low cost by using a simple manufacturing process at a relatively low cost with a low compression set and no surface bleed due to a softener or the like.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an example of a usage mode of a developing roller of the present invention.

FIG. 2 is an explanatory diagram of a configuration of a conventional developing roller.

FIG. 3 is an explanatory diagram of an example of the developing device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Container 3 Developing roller 3a Core metal 3b Conductive thermoplastic elastomer composition 3c Conductive elastic layer or conductive foam layer 3d Conductive resin coating layer 4 Developing blade 5 Elastic roller 6 Toner

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08L 23/16 C08L 23/16 51/06 51/06 91/00 91/00 F16C 13/00 F16C 13/00 EA G03G 15/08 501 G03G 15/08 501D F-term (reference) 2H077 AD06 BA09 EA14 EA15 FA13 FA22 3J103 AA02 AA12 AA85 BA41 FA14 FA30 GA57 GA58 HA03 HA12 HA20 HA46 4F070 AA16 AA54 AA63 AB03 AB08 AC02 GA13 AC07 AE04 AE05Y BB15X BB204 BB214 BN034 CD194 CH05W CL07W CL08W DA036 DA076 DA096 DE096 DE106 DE136 EA018 EK027 EK037 EK047 ET007 FB076 FB288 FD116 FD147 FD150 GB00 GN00 GQ00

Claims (17)

[Claims] 1. A polyamide elastomer (A),
0 ° C Mooney viscosity (ML _{1 + 4} 100 ° C) is 120-350
Oil-extended olefin copolymer rubber (B), modified polyolefin resin (C), conductive filler (D) containing 20 to 150 parts by mass of a mineral oil-based softening agent per 100 parts by mass of olefin copolymer rubber (A) /
((B) + (C)) = 70-15 / 30-85 parts by mass, (D) 1-100 parts by mass with respect to (A) + (B) + (C) 100 parts by mass, A conductive thermoplastic elastomer composition, wherein (A) forms a matrix phase and (B) a dispersed phase, and (D) is selectively present in (A). 2. Kneading (A), (B) and (C) with an additive selected from a crosslinking agent, a softening agent and the like, and subjecting (B) to a crosslinking reaction under shearing force when (A) is melted. The conductive thermoplastic elastomer composition according to claim 1, further comprising a step of causing the conductive thermoplastic elastomer composition to have a composition. 3. The conductive thermoplastic elastomer composition according to claim 1, wherein the addition of (D) is performed after the completion of the crosslinking reaction of (B). 4. The olefin-based copolymer rubber is an ethylene-propylene-non-conjugated diene-based rubber.
The conductive thermoplastic elastomer composition according to any one of the above. 5. An ethylene-propylene-non-conjugated diene rubber having a propylene content of 10 to 55% by mass and an ethylidene norbornene content of 1 to 30% by mass.
The conductive thermoplastic elastomer composition according to any one of claims 1 to 4, which is a propylene-ethylidene norbornene copolymer rubber. 6. The oil-extended olefin copolymer rubber (B) having a Mooney viscosity (ML _{1 + 4 at} 100 ° C.) of 30 to 10 ° C.
The conductive thermoplastic elastomer composition according to any one of claims 1 to 5, which is 0. 7. The conductive material according to claim 1, wherein the polyamide elastomer (A) is a block copolymer of polyamide and polyether, and the polyamide content is 20 to 80% by mass. Thermoplastic elastomer composition. 8. The hardness (J) of the thermoplastic elastomer composition.
The conductive thermoplastic elastomer composition according to any one of claims 1 to 7, wherein IS A) is 15 to 50 degrees. 9. The method further comprises the addition of the thermally expandable hollow particles (E)
9. The composition according to claim 1, wherein the addition of -30 parts by mass is carried out.
The conductive thermoplastic elastomer composition according to any one of the above. 10. The heat-expandable hollow particles (E) according to claim 1.
A foam elastic roller characterized by being dry-blended to the composition of any one of (1) to (3) and foamed. 11. The conductive thermoplastic elastomer composition according to claim 9, wherein the thermoplastic elastomer composition has a hardness (Asker C) of 15 to 50 degrees. 12. An elastic roller using the conductive thermoplastic elastomer composition according to claim 1 as a developing roller. 13. A developing device comprising: a developer accommodating container for accommodating a one-component developer; and a developing roller for carrying and transporting the developer from the container to a developing section, wherein the developing roller is the elastic roller according to claim 12. A developing device, characterized in that: 14. A process cartridge in which at least an electrophotographic photosensitive member and a developing device are integrally formed as a cartridge and which is detachably mountable to an image forming apparatus main body, wherein the developing value stores a one-component developer. 14. A developing device comprising: a container; and a developing roller for carrying and transporting a developer from the container to a developing unit, wherein the developing roller is
A developing device, comprising the elastic roller according to (1). 15. A developing device comprising: a developer accommodating container for accommodating a one-component developer; and a developing roller for carrying and transporting the developer from the container to a developing section, wherein the developing roller is an elastic foam roller according to claim 10. A developing device. 16. A process cartridge in which at least the electrophotographic photosensitive member and the developing device are integrally formed as a cartridge and which is detachable from the main body of the image forming apparatus, wherein the developing value is a developer accommodating a one-component developer. 11. A developing device comprising a container, and a developing roller for carrying and transporting a developer from the container to a developing unit, wherein the developing roller is
A developing device comprising the elastic foaming roller according to item 1. 17. Recovering a conductive thermoplastic elastomer composition from a used device by using a roller selected from the elastic roller or the elastic foam roller according to claim 10 or 12,
How to regenerate to the roller again.