JP2000122405A - Developing roller adopted for non-magnetic non-contact developing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing roller provided with stable developing property by disposing a conductive elastic layer with a specified resistance, on a conductive supporting body. SOLUTION: This roller provided with the conductive elastic layer is pressed on a shaft as the conductive supporting body in parallel with a plate-like electrode, and AC voltage 100 V is applied, in a state of respectively imparting a load of 500 (g) on both end of the shaft. Then, the conductive elastic layer having resistance that is 1×105 to 5×107 Ω at this time, is disposed on the conducting supporting body. When the resistance comes to the value below 1×105 Ω, the discharge occurs, therefore an image unevenness becomes liable to occur. On the other hand, when it exceeds 5×107 Ω, a potential difference necessary for shifting toner on the electrostatic latent image can not be obtained and the sufficient image density can not be attained, therefore the excellent image can not be obtained. Preferably, in order to obtain an excellent image, the resistance as shown below is preferable; 1×105 to 5×106 Ω. Moreover, it is desirable to furnish the single or plural coating layer outside the conductive elastic layer, provided that the resistance of the conducting layer falls in this range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a copying machine,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing roller incorporated in a device employing an electrophotographic method such as a printer or a facsimile receiving device, which uses a non-magnetic toner and is used in a non-magnetic non-contact developing method which is not in contact with a photosensitive member.

[0002]

2. Description of the Related Art In an image forming apparatus adopting an electrophotographic system, a charging roller for uniformly charging the surface of an electrostatic latent image carrier and toner carrying an electrostatic latent image are provided around the electrostatic latent image carrier. Various rollers such as a developing roller for supplying to the body and a transfer roller for transferring the toner image to the recording paper are arranged. The method of carrying the toner on the surface of the developing roller and moving the toner to the electrostatic latent image is largely divided into a non-magnetic developing method and a magnetic developing method. The magnetic developing method is a method in which a magnetic toner is adhered to the surface of a developing roller by magnetic force, and the non-magnetic developing method is a method in which non-magnetic toner is adhered to the surface of a developing roller by electrostatic force without using magnetic force. is there. The non-magnetic developing method has attracted attention in recent years because it has the advantages that the toner can be easily colored and a good halftone image can be obtained in monochrome image formation, as compared with the magnetic developing method.

FIG. 1 is a schematic diagram showing an example of a developing device 1 disposed in an image forming apparatus employing a non-magnetic developing system and a photosensitive member 2 serving as an electrostatic latent image carrier. As the photoconductor 2, a negatively chargeable organic photosensitive drum or the like is used. The developing device 1 includes a toner container 4 for storing the non-magnetic toners 3, 3, a regulating blade 5 provided in the toner container 4, and a developing roller 6.
And a supply roller 7. The developing roller 6 has an elastic layer 9 having rubber elasticity formed around a conductive support 8 such as a metal shaft. It is covered with a coating layer 10 for prevention or the like. The toners 3, 3 in the toner container are supplied to the surface of the developing roller 6 by the supply roller 7, and then pressed by the regulating blade 5 to form a thin toner layer. When the toner becomes a thin toner layer, the toner is charged electrically and frictionally. This thin layer of toner is
The electrostatic latent image on the surface of No. 2 is electrostatically attracted and becomes a toner image on the photoreceptor surface, so that the development is performed.

The developing system includes a contact type in which the photosensitive member is brought into contact with the developing roller and a non-contact type in which both are not in contact with each other. In either method, it is necessary to apply an appropriate voltage between the photoconductor and the developing roller in order to move the toner to the surface of the photoconductor.However, in the non-contact type, the toner is filled in a gap between the photoconductor and the developing roller. In order to fly, it is necessary to apply an AC voltage in addition to a DC voltage between the two to form an AC electric field in the gap.

[0005] In the contact method, since only a DC voltage is applied in many cases, if the resistance of the elastic layer is lower than the resistance of the coating layer having the highest resistance, it is not necessary to control the resistance closely.
In the non-contact development method, since an AC voltage is also applied, capacitance and the like become important in addition to the resistance, and the roller resistance determined by the resistance of the coating layer having the highest resistance alone is not sufficient for the electrical side of the roller. At present it is not possible to design.

[0006]

SUMMARY OF THE INVENTION The present invention provides a guideline for designing the electric side of a roller in a non-magnetic non-contact developing system in which an AC voltage is applied as described above, and provides a developing roller having stable developing characteristics. It is intended to provide.

[0007]

Means for Solving the Problems As a result of intensive studies on the above object, the present inventors have found that the resistance of the conductive elastic layer is important in the non-magnetic non-contact developing system, and completed the present invention. did. That is, the present invention is a developing roller for an electrophotographic machine used in a non-magnetic non-contact developing system, which has a conductive elastic layer on at least a conductive support, and the conductive elastic layer when a DC voltage of 100 V is applied. The developing roller has a resistance of 1 × 10 ⁵ Ω to ⁵ × 10 ⁷ Ω. (Claim 1) A variation in the axial resistance of the conductive support of the conductive elastic layer is one.
The developing roller according to claim 1, wherein the developing roller is within one digit (claim 2). A single-layer or multiple-layer coating layer is provided outside the conductive elastic layer. The developing roller according to any one of claims 1 to 3, wherein a surface layer of the developing roller is made of a resin composition having an -NHCO- bond. The conductive elastic layer (A) has at least one alkenyl group in a molecule,
Polymer wherein the repeating unit constituting the main chain is an oxyalkylene unit or a saturated hydrocarbon unit (B) a curing agent having two or more hydrosilyl groups in a molecule (C) a hydrosilylation catalyst and (D) conductivity imparting 5. The developing roller according to claim 1, wherein the developing roller comprises a reaction product of a conductive curable composition containing an agent as a main component. .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The developing roller according to the present invention has a conductive elastic layer on a conductive support, and if necessary, improves the adhesiveness, protects the surface, and further adjusts the toner charge. This is a configuration in which a coating layer for the purpose is laminated.

The developing roller used in the present invention is used in the non-magnetic non-contact developing system as described above.
In the case of this method, as a result of the contribution of the capacitance and the like from the roller resistance itself governed by the resistance of the layer having the highest resistance,
The resistance of the conductive elastic layer is most important. As shown in FIG. 2, the resistance of the conductive elastic layer is such that a roller having a conductive elastic layer is pressed in parallel to a plate electrode on a shaft which is a conductive support, and a load of 500 g is applied to both ends of the shaft in the direction of the plate electrode. Is measured when a DC voltage of 100 V is applied, and the resistance is preferably 1 × 10 ^{5 to} 5 × 10 ⁷ Ω.

1 × 10^FiveBelow Ω, discharge occurs and the image
Unevenness is likely to occur. 5 × 10⁷Over Ω
A sufficient potential difference is obtained to transfer the toner to the electrostatic latent image.
Image density cannot be obtained, and a good image cannot be obtained.
No. Preferably 1 × 10 ^Five~ 5 × 10⁶Ω is good
This is advantageous in that the design range of the developing device for obtaining favorable images is widened.
Good.

In the above description, the overall resistance in the roller axial direction at the time of forming the conductive elastic layer was described. However, when the resistance was measured by subdividing the roller axial direction, the resistance variation in the roller axial direction was within one digit. It is desirable that As used herein, the resistance when the roller is divided in the axial direction is, as shown in FIG. 3, the resistance between the electrode having a width of 4 mm and the shaft instead of the flat electrode of FIG. Positioning evenly with respect to the length in the direction). Almost good images can be obtained if the variation in the axial resistance is within one digit. However, it is needless to say that the variation in the axial direction is more preferably less than 0.5 digit.

When the resistance of the conductive elastic layer is within the above range,
A single-layer or multiple-layer coating layer may be provided outside the conductive elastic layer. The difference between the outer diameter of the roller and the outer diameter of the elastic layer after the provision of the coating layer is preferably 200 μm or less (the thickness of the coating layer is 100 μm) or less from the viewpoint of controlling the image by controlling the resistance of the conductive elastic layer. This is because when the thickness is extremely large, the contribution ratio of the coating layer such as the capacitance increases.

The resistance of the conductive elastic layer is 1 × 10 ^{5 to} 5
When the resistance is × 10 ⁷ Ω, the resistance of the developing roller when a single or multiple coating layer is provided outside the conductive elastic layer is 10 ⁵ to 10 ¹¹ Ω, preferably 10 ⁵ Ω in the above-described measuring method. ~
What is necessary is just to be 10 ⁸ Ω.

When a coating layer is provided, the binder resin of the outermost surface layer is nylon, urethane,
Fluoro rubber and the like, but from the viewpoint of improving the charging characteristics of the negatively charged toner, -N such as polyamide or polyurethane may be used.
It is preferred that the resin composition has an HCO-bond.

[0015] Specific examples of the polyamide include N-methoxymethylated nylon (usually called 8-nylon).
But not particularly limited thereto.

Among the above-mentioned polyurethanes, a polyurethane containing a polyether skeleton is preferable from the viewpoint of imparting appropriate flexibility to the surface layer. Polycarbonate urethane is preferable from the viewpoint of stability in an environment of high temperature and high humidity, and silicone-modified polyurethane is preferable from the viewpoint of preventing toner filming, but is not particularly limited.

The coating method of the coating layer is not particularly limited, but a simple method of dissolving the solvent-soluble coating layer binder resin in a solvent to have a solid content of 5 to 15% and spraying or dipping is convenient.

Next, the conductive elastic layer will be described.
As a preferred conductive elastic layer, (A) a polymer containing at least one alkenyl group in a molecule and having a main chain composed mainly of oxyalkylene units or saturated hydrocarbon units, and (B) ) At least 2 in the molecule
It is preferable to use a reaction product of a curable composition containing, as main components, a curing agent containing one hydrosilyl group, (C) a hydrosilylation catalyst, and (D) a conductivity-imparting agent. When the conductive elastic layer is made of an oxyalkylene-based composition, the composition has a low viscosity before curing and has a low hardness after curing, so that it is preferable from the viewpoint of workability. When composed of a system composition, this composition has a low water absorption, and is therefore preferable from the viewpoint of stability in a high humidity environment.

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) is required to be at least one from the viewpoint of performing a hydrosilylation reaction with the component (B), but from the viewpoint of rubber elasticity, in the case of a linear molecule, In the case of a molecule having two alkenyl groups at both ends and a branched molecule, it is preferable that two or more alkenyl groups are present at the molecular ends. (A)
The main repeating unit constituting the main chain of the component is an oxyalkylene unit or a saturated hydrocarbon unit.

A polymer in which the main repeating unit constituting the main chain is an oxyalkylene unit is preferred because it can be easily adjusted to a predetermined resistance simply by adding a small amount of a conductivity-imparting agent. Further, from the viewpoint of lowering the hardness of the cured product, an oxyalkylene-based polymer in which the repeating unit is an oxyalkylene unit, and more preferably an oxypropylene-based polymer in which the repeating unit is an oxypropylene unit.

Here, the oxyalkylene-based polymer refers to a polymer in which 30% or more, preferably 50% or more, of the units constituting the main chain are composed of oxyalkylene units. Examples of the unit include compounds derived from a compound having two or more active hydrogens, such as ethylene glycol, bisphenol compounds, glycerin, trimethylolpropane, and pentaerythritol, which are used as a primary substance in the production of a polymer. Can be In the case of an oxypropylene-based polymer, it may be a copolymer (including a graft polymer) with a unit composed of ethylene oxide, butylene oxide, or the like.

The molecular weight of the oxyalkylene polymer as the component (A) is from 500 to 50,000 in terms of number average molecular weight (Mn) from the viewpoint of improving the balance between reactivity and low hardness. Is 1,000-40,0
00 is preferred. In particular, the number average molecular weight is 5,0
Those having a value of 00 or more, more preferably those having a molecular weight of 5,000 to 40,000 are preferred. 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 molecular weight per alkenyl group contained in the molecule will be large, or the reactivity will decrease due to steric hindrance, so curing is often 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 may be represented by the following general formula (1): H ₂ C ＝ C (R ¹ )-(1) (wherein R ¹ is a hydrogen atom or The alkenyl group represented by (methyl group) is particularly preferable in terms of excellent curability.

One of the characteristics of the curable composition is as follows.
In order to exhibit this characteristic, the number of alkenyl groups is preferably 2 or more at the molecular terminal, and the number of alkenyl groups becomes too large compared to the molecular weight of component (A). And it becomes difficult to obtain good rubber elasticity.

In 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, it has a low water absorption and is preferable because the environmental fluctuation of electric resistance is small. This polymer is also a component which is cured by a hydrosilylation reaction with the component (B), as in the case of the oxyalkylene polymer, and has at least one alkenyl group in the molecule. The component (A) is required to have at least one alkenyl group from the viewpoint of a hydrosilylation reaction with the component (B).
From the viewpoint of rubber elasticity, in the case of a linear molecule, two molecules are preferably present at both ends of the molecule, and in the case of a molecule having a branch, two or more molecules are preferably present at the molecular terminal.

Typical examples of the polymer in which the main repeating unit constituting the main chain is a saturated hydrocarbon-based unit include:
Examples 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% of a saturated hydrocarbon-based unit may be contained.
As described above, 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 system having a low water absorption.

The molecular weight of the polymer of the component (A) in which the main repeating unit constituting the main chain is a saturated hydrocarbon-based unit is as follows.
n) about 500 to 50,000, and even 1,000
~ 15,000, and a liquid material having fluidity at room temperature is preferable from the viewpoint of processability. The alkenyl group introduced into the saturated hydrocarbon polymer is the same as in the case of the oxyalkylene polymer.

Therefore, preferred specific examples of the polymer having at least one alkenyl group in the molecule and having a main repeating unit constituting a main chain of a saturated hydrocarbon as the component (A) include: A linear number average molecular weight (Mn) having two alkenyl groups at both ends is from 2,000 to 1
Examples thereof include a polyisobutylene-based, hydrogenated polybutadiene-based, and hydrogenated polyisoprene-based polymer having a molecular weight of 5,000 and an 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 contained in the molecule is too large. After curing, a large amount of hydrosilyl groups easily remain in the cured product and cause voids and cracks. Therefore, the number of hydrosilyl groups contained in the molecule is preferably 50 or less. Further, the number is preferably 2 to 30, more preferably 2 to 20, from the viewpoint of control of rubber elasticity and storage stability of the cured product. Further, in order to easily prevent foaming during curing, 20 In the following, from the viewpoint that curing failure does not easily occur even when the hydrosilyl group is deactivated, three are preferable, and the most preferable range is 3 to 20.

In the present invention, the above-mentioned hydrosilyl group is
The term “having one” means having one H bonded to Si. In the case of SiH ₂ , it has two hydrosilyl groups, but the H bonded to Si is harder to bond to different Si. And also preferable from the viewpoint of rubber elasticity.

The molecular weight of the component (B) is 30,000 in terms of number average molecular weight (Mn) from the viewpoint of dispersibility and roller workability when a conductivity imparting agent (component (D)) described below is added.
Or less, more preferably 20,000 or less,
In particular, 15,000 or less is preferable. Considering the reactivity and compatibility of the component (A), 300 to 10,000 is preferable.

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, and the component (A) Styrene-modified products are preferred from the viewpoint of compatibility with the components and availability, and α-methylstyrene-modified products are preferred from the viewpoint of storage stability.

The hydrosilylation catalyst as the component (C) is not particularly limited as long as it can be used as a hydrosilylation catalyst. Platinum simple substance, solid platinum supported on simple substance such as alumina, chloroplatinic acid (including complex such as alcohol), various complexes of platinum, chloride of metal such as rhodium, ruthenium, iron, aluminum, titanium, etc. No. 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 components (A) and (B) used 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). -5.0 mol, more preferably 0.4-2.5 mol, from the viewpoint of rubber elasticity.

The amount of component (C) used is as follows:
(A) 10 ^-1 to 1 based on 1 mol of the alkenyl group in the component.
0 ^-8 mol, more preferably 10 ^-1 to 10 ^-6 mol, especially 10 ^-3 mol
It is preferably used in the range of from 10 to ⁶ mol. If the amount of component (C) is less than 10 ^-8 mol, the reaction does not proceed.
On the other hand, hydrosilylation catalysts are generally expensive and have a corrosive, and since the cured product hydrogen gas generate a large amount has a property that results in foaming greater than 10 ^-1 mol It is preferable not to use them.

Further, the curable composition as described above has
If a conductive composition is obtained by adding a conductivity-imparting agent as the component (D), 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 of the compound include a compound that can impart conductivity. These conductivity imparting agents may be used alone or in combination of two or more.

The added 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), from the viewpoint of not increasing the rubber hardness.
On the other hand, from the viewpoint of obtaining a uniform resistance, the content is preferably 10% by weight or more, and the addition amount may be determined based on the balance between the required physical properties of rubber hardness and resistance.

Further, in addition to the components (A) to (D), a storage stability improving agent such as a compound having an aliphatic unsaturated bond, an organic phosphorus compound, an organic sulfur compound, A nitrogen-containing compound, a tin-based compound, an organic peroxide, or the like may be added. Specific examples thereof include, for example, benzothiazole, thiazole, dimethylmalate, dimethylacetylenecarboxylate,
Examples include, but are not limited to, 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.

The curable composition may contain a filler, a storage stabilizer, a plasticizer, a UV absorber, a lubricant, a pigment, and the like for improving processability and cost.

The developing roller according to the present invention comprises the above-mentioned curable composition and other elastic materials such as urethane rubber, chloroprene rubber, EP rubber, etc.
The conductive elastic layer is formed around the shaft by casting, injecting, extruding, etc. into a mold equipped with a conductive shaft consisting of a metal shaft made of US etc. and heating and curing at an appropriate temperature and time. Form. In this case, post-curing may be performed after semi-curing. From above this conductive elastic layer,
The developing roller of the present invention is obtained by applying the resin constituting the surface layer to a predetermined thickness by spray coating, dip coating, or the like, and drying and curing at a predetermined temperature.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The constructions of Embodiments 1 to 9 according to the present invention will be described below in detail, and then comparisons between these embodiments and Comparative Examples 1 and 2 will be made.

The developing rollers of these Examples and Comparative Examples have a thickness of about 3 m around a SUS shaft having a diameter of 10 mm.
m conductive elastic layers were provided concentrically, and a surface layer was coated on the elastic layers.

For the conductive elastic layer, any one of the elastic layers 1 to 8 described below is used. (Conductive Elastic Layer 1) (A-1) Allyl-terminated polyoxypropylene polymer having a number average molecular weight (Mn) of 8,000 and a molecular weight distribution of 2: 1
(B-1) polysiloxane-based curing agent (SiH value: 0.36 mol / 100 g): 6.6 parts by weight, (C-1) 10% chloroplatinic acid solution in 10% isopropyl alcohol: 0 parts by weight 0.06 parts by weight, (D) carbon black #
35 (manufactured by Asahi Carbon Co., Ltd.): 3 parts by weight,
(0 mmHg or less, 120 minutes). The obtained composition was coated around the shaft, and allowed to stand for 30 minutes in a mold at 120 ° C. for 30 minutes to cure, thereby producing a rubber elastic body having a thickness of about 3 mm. The roller resistance at the time of molding the conductive rubber elastic body was 1.2 × 10 ⁸ Ω, and the variation at 10 points in the axial direction was 0.4 digits. (Conductive Elastic Layer 2) (A-1) Allyl-terminated polyoxypropylene polymer having a number average molecular weight (Mn) of 8,000 and a molecular weight distribution of 2: 1
(B-1) polysiloxane-based curing agent (SiH value: 0.36 mol / 100 g): 6.6 parts by weight, (C-1) 10% chloroplatinic acid solution in 10% isopropyl alcohol: 0 parts by weight 0.06 parts by weight, (D) carbon black #
35 (manufactured by Asahi Carbon Co., Ltd.): 5 parts by weight,
(0 mmHg or less, 120 minutes). The obtained composition was coated around the shaft, and allowed to stand for 30 minutes in a mold at 120 ° C. for 30 minutes to cure, thereby producing a rubber elastic body having a thickness of about 3 mm. The roller resistance at the time of molding the conductive rubber elastic body was 4.2 × 10 ⁷ Ω, and the variation at 10 points in the axial direction was 0.72 digits.

(Conductive Elastic Layer 3) (A-1) Allyl-terminated polyoxypropylene polymer having a number average molecular weight (Mn) of 8,000 and a molecular weight distribution of 2: 1
(B-1) polysiloxane-based curing agent (SiH value: 0.36 mol / 100 g): 6.6 parts by weight, (C-1) 10% chloroplatinic acid solution in 10% isopropyl alcohol: 0 parts by weight 0.06 parts by weight, (D) carbon black #
35 (manufactured by Asahi Carbon Co., Ltd.): 7 parts by weight
(0 mmHg or less, 120 minutes). The obtained composition was coated around the shaft, and allowed to stand for 30 minutes in a mold at 120 ° C. for 30 minutes to cure, thereby producing a rubber elastic body having a thickness of about 3 mm. The roller resistance at the time of molding the conductive rubber elastic body was 3.7 × 10 ⁶ Ω, and the variation at 10 points in the axial direction was 0.81 digit.

(Conductive Elastic Layer 4) (A-1) Allyl-terminated polyoxypropylene polymer having a number average molecular weight (Mn) of 8,000 and a molecular weight distribution of 2: 1
(B-1) polysiloxane-based curing agent (SiH value: 0.36 mol / 100 g): 6.6 parts by weight, (C-1) 10% chloroplatinic acid solution in 10% isopropyl alcohol: 0 parts by weight 0.06 parts by weight, (D) carbon black #
35 (manufactured by Asahi Carbon Co., Ltd.): 9 parts by weight
(0 mmHg or less, 120 minutes). The obtained composition was coated around the shaft, and allowed to stand for 30 minutes in a mold at 120 ° C. for 30 minutes to cure, thereby producing a rubber elastic body having a thickness of about 3 mm. The roller resistance at the time of molding the conductive rubber elastic body was 1.7 × 10 ⁵ Ω, and the variation at 10 points in the axial direction was 0.72 digits. (Conductive Elastic Layer 5) (A-1) Allyl-terminated polyoxypropylene polymer having a number average molecular weight (Mn) of 8,000 and a molecular weight distribution of 2: 1
(B-1) polysiloxane-based curing agent (SiH value: 0.36 mol / 100 g): 6.6 parts by weight, (C-1) 10% chloroplatinic acid solution in 10% isopropyl alcohol: 0 parts by weight 0.06 parts by weight, (D) carbon black #
35 (manufactured by Asahi Carbon Co., Ltd.): 12 parts by weight were mixed and degassed (10 mmHg or less, 120 minutes). The resulting composition was coated around the shaft and placed in a mold at 120 ° C.
The mixture was allowed to stand for 30 minutes in the environment described above to be cured, thereby producing a rubber elastic body having a thickness of about 3 mm. The roller resistance at the time of forming the conductive rubber elastic body was 3.2 × 10 ⁴ Ω, and the dispersion at 10 points in the axial direction was 0.52 digits. (Conductive elastic layer 6) (A-1) Number average molecular weight ( Mn) 8,000, terminal allylated polyoxypropylene polymer having a molecular weight distribution of 2: 1
(B-1) polysiloxane-based curing agent (SiH value: 0.36 mol / 100 g): 6.6 parts by weight, (C-1) 10% chloroplatinic acid solution in 10% isopropyl alcohol: 0 parts by weight 0.06 parts by weight, (D) carbon black #
15 (manufactured by Asahi Carbon Co., Ltd.): 12 parts by weight were mixed and degassed (10 mmHg or less, 120 minutes). The resulting composition was coated around the shaft and placed in a mold at 120 ° C.
The mixture was allowed to stand for 30 minutes in the environment described above to be cured, thereby producing a rubber elastic body having a thickness of about 3 mm. The roller resistance at the time of molding the conductive rubber elastic body was 2.4 × 10 ⁶ Ω, and the variation at 10 points in the axial direction was 0.48 digits. (Conductive Elastic Layer 7) (A-2) A polyisobutylene polymer having a number average molecular weight (Mn) of 10,000 and having two vinyl groups at a terminal: 100
Parts by weight, (B-2) polysiloxane-based curing agent (SiH value 0.97 mol / 100 g): 2.7 parts by weight, (C-1)
10% isopropyl alcohol solution of chloroplatinic acid: 0.
A composition consisting of 0.6 parts by weight, (D) carbon black # 35 (manufactured by Mitsubishi Chemical Corporation): 10 parts by weight, and (other) plasticizer PS-32 (manufactured by Idemitsu Kosan Co., Ltd.): 75 parts by weight. Coated around, 30 minutes in a mold at 120 ° C
For about 3 minutes to cure the conductive elastic layer 7 having a thickness of about 3 mm.
Was prepared. The roller resistance after molding is 2.5 × 10 ⁵ Ω,
The variation at 10 points in the axial direction was 0.74 digits. (Conductive Elastic Layer 8) (A-1) Allyl-terminated polyoxypropylene-based polymer having a number average molecular weight (Mn) of 8,000 and a molecular weight distribution of 2: 1
(B-1) polysiloxane-based curing agent (SiH value: 0.36 mol / 100 g): 6.6 parts by weight, (C-1) 10% chloroplatinic acid 10% isopropyl alcohol solution: 0 parts by weight 0.06 parts by weight, (D) carbon black #
3030B (manufactured by Mitsubishi Chemical Corporation): 6 parts by weight, and degassing was performed under reduced pressure (10 mmHg or less, for 120 minutes). The resulting composition was coated around the shaft and placed in a mold at 120 ° C.
The mixture was allowed to stand for 30 minutes in the environment described above to be cured, thereby producing a rubber elastic body having a thickness of about 3 mm. The roller resistance at the time of molding the conductive rubber elastic body was 2.8 × 10 ⁵ Ω, and the variation at 10 points in the axial direction was 1.48 digits. Next, the surface layers were the surface layers 1 to 4 shown below. Either one was applied to the outer periphery of the conductive elastic layer by dipping and dried. The drying was performed at 80 ° C. for 1 hour. (Surface layer 1) A solution of 8220LP (Polycarbonate polyurethane manufactured by Dainichi Seika) with methyl ethyl ketone / dimethylformamide = 1/1 to have a solid content of 5% was prepared. (Surface layer 2) A solution similar to the surface layer 1 was prepared except that carbon black # 45L (manufactured by Mitsubishi Chemical Corporation) was added in an amount of 20 parts by weight based on 100 parts by weight of the solid content of the surface layer 1. (Surface layer 3) A solution was prepared by diluting EM-125 (methoxymethylated nylon manufactured by Lead City Co., Ltd.) with methanol to a solid content of 10%. (Surface layer 4) Sefralsoft G-180Y (fluorine system manufactured by Central Glass Co., Ltd.)
%, And a solution diluted so as to have a concentration of 0.1% was prepared.

[0046]

[Table 1] The roller shown in Table 1 was incorporated in the position of the developing roller of a non-magnetic non-contact image evaluation machine to evaluate a solid black image.

[0047]

[Table 2] As shown in Table 2, the resistance of the main conductive elastic layer is 1 × 10 ⁵ to
In Comparative Examples 1 and 2 out of the range of 5 × 10 ⁷ Ω, the image density is low or white spots occur. Comparing Examples 4 and 5, it can be seen that the resistance of the surface layer does not significantly contribute to the image.

[0048]

As shown in Table 2, in the developing roller used in the non-magnetic non-contact system, the resistance of the conductive elastic layer is 1%.
It is important that the value is from 10 ^{5 to} 5 10 ⁷ Ω. The axial variation of the conductive elastic layer is preferably within one digit, and the material of the surface layer preferably has an -NHCO- bond.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a method of measuring the resistance of a developing roller.

FIG. 3 is a diagram showing electrodes used for resistance measurement when the roller is subdivided in the axial direction.

[Explanation of symbols]

 Reference Signs List 1 developing device 2 photoreceptor 3 non-magnetic toner 4 toner container 5 regulating blade 6 developing roller 7 supply roller 8 conductive support 9 elastic layer 10 surface layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H077 AD06 EA14 EA16 FA13 FA22 FA25 3J103 AA02 AA14 AA23 AA33 AA51 BA41 FA30 GA02 GA57 GA58 GA60 GA74 HA03 HA12 HA20 HA41

Claims (5)

[Claims] 1. A developing roller for an electrophotographic machine used in a non-magnetic non-contact developing method, comprising a conductive elastic layer on at least a conductive support, wherein the conductive elastic layer is applied when a DC voltage of 100 V is applied. A developing roller having a resistance of 1 × 10 ⁵ Ω to ⁵ × 10 ⁷ Ω; 2. The developing roller according to claim 1, wherein the variation in the axial resistance of the conductive support of the conductive elastic layer is within one digit. 3. The developing roller according to claim 1, wherein a single layer or a multiple layer is provided outside the conductive elastic layer. 4. The developing roller according to claim 1, wherein the surface layer of the developing roller comprises a resin composition having an —NHCO— bond.
4. The developing roller according to any one of 3. 5. The conductive elastic layer (A) has at least one alkenyl group in a molecule,
Polymer wherein the repeating unit constituting the main chain is an oxyalkylene unit or a saturated hydrocarbon unit (B) a curing agent having two or more hydrosilyl groups in a molecule (C) a hydrosilylation catalyst and (D) conductivity imparting The developing roller according to any one of claims 1 to 4, wherein the developing roller comprises a reaction product of a conductive curable composition containing an agent as a main component.