JPH1069165A - Roller and device for developing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image of high definition being free from a density unevenness, ground fogging or the like, and to prevent deterioration of the image quality regardless of the use over a long term by means of this developing roller. SOLUTION: In this developing roller composed of a conductive elastic layer 3 formed on a periphery of a conductive shaft 2, feeding the one component developer, by carrying the developer, on the elastic layer surface and forming the thin layer of the developer, when the elastic layer 3 contains the resin property on the surface, and assuming the roller resistance as R1 in the case the resin property is not provided while assuming the roller resistance as R2 in the case the resin property is provided, the following relation is satisfied, log (R2 /R1 )<=3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus such as a copying machine or a printer, an electrostatic recording apparatus, or the like. More specifically, a developing roller for forming an image and a developing device using the developing roller have excellent stain resistance and can reliably obtain a good image even in long-term use. Developing device.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic apparatus such as a copying machine or a printer, or an electrostatic recording apparatus, a non-magnetic one-component developer is supplied to a photosensitive drum holding a latent image and the latent image on the photosensitive drum is supplied to the photosensitive drum. As a developing method for visualizing a latent image by attaching a developer, a pressure developing method is known (US Pat. No. 3,152,352).
No. 012, No. 3731146, etc.), according to this method, the magnetic material is unnecessary, so that the apparatus can be easily simplified and downsized, and the toner can be easily colored.

In this pressure development method, toner is supplied to the surface of a latent image holding member such as a photosensitive drum from a developing roller carrying a toner (a non-magnetic one-component developer) on the surface, and the latent image holding member has a latent image holding member. The toner image is formed on the surface of the latent image holding member by attaching it to the image.

That is, in this pressure development method, for example, as shown in FIG. 2, a toner-applying roller 4 for supplying toner and a photosensitive drum 5 holding an electrostatic latent image are provided. The developing roller 1 is disposed in contact with or close to the photosensitive drum 5 (in the figure, a state in which the developing roller 1 is separated from the photosensitive drum 5),
By rotating these developing roller 1, photosensitive drum 5, and toner coating roller 4 in the direction of the arrow in the figure,
The toner 6 is supplied to the surface of the developing roller 1 by the toner applying roller 4, and the toner is arranged in a uniform thin layer by the layering blade 7. In this state, the developing roller 1 is brought into contact with or close to the photosensitive drum 5 and rotates. As a result, the toner formed in a thin layer adheres to the latent image on the photosensitive drum 5 from the developing roller 1 and the latent image is visualized.
In the drawing, reference numeral 8 denotes a transfer unit, which transfers a toner image to a recording medium such as paper. Reference numeral 9 denotes a cleaning unit, which is provided on the surface of the photosensitive drum 5 after transfer by a cleaning blade 10. The remaining toner is removed.

In this case, as shown in FIG. 1, a developing roller 1 is generally provided with an elastic rubber such as silicone rubber, NBR, EPDM, urethane foam, or the like around a shaft 2 made of a good conductive material such as metal. An elastic layer 3 made of an elastic body provided with conductivity by blending a conductive agent with the conductive material is formed.

Further, as disclosed in JP-A-58-116559, a non-magnetic toner having a thin layer is formed on the surface of a developing sleeve disposed in a non-contact state close to a latent image holding member. There is also proposed a method in which the toner is carried onto the latent image holding member, the toner is supplied to the latent image holding member, and development is performed. Further, a method of forming an image by supplying toner directly from a developing roller to a recording medium such as a paper sheet such as paper, OHP, photographic paper, etc., when the latent image holding member is not a drum shape but a belt shape. In such a method, a similar developing roller can be used.

[0007]

However, the conventional developing roller has the following disadvantages due to the characteristics of the elastic layer. 1. When the elastic layer is formed of an elastic rubber such as silicone rubber, NBR, EPDM or the like, if the hardness is reduced to obtain good adhesion, contamination of the photosensitive drum may occur in the case of the pressure development method. 2. When the elastic layer is formed of a sponge body such as urethane foam, the toner penetrates into the elastic layer, and if used for a long period of time, the roller becomes hard due to toner clogging or toner charging failure occurs, resulting in poor image quality. May decrease. This tendency applies not only to the sponge body but also to a roller having a surface to which toner easily adheres. 3. In general, when the developing roller is composed of a single layer, the surface friction coefficient is very large, so that a large load is applied between the developing blade, the photoconductor, the electrode, and the like, resulting in non-uniform toner conveyance or jitter in driving. This tends to cause image defects. In general, a developing roller composed of a single elastic layer does not have sufficient charge rising characteristics of toner on the roller, and the surface of the roller is easily contaminated with toner. The problem described above is likely to occur, and in particular, the print quality is significantly reduced by long-term continuous printing. Such development is remarkable in non-magnetic toner development in which the toner charge amount needs to be set relatively high.

The present invention has been made in view of the above circumstances, and can provide a high-quality image free from inconsistencies such as contamination of an image forming body such as a photoreceptor and without uneven density or fogging. Another object of the present invention is to provide a developing roller and a developing device using the developing roller, which do not cause deterioration in image quality even when used for a long time.

[0009]

Means for Solving the Problems and Actions The present inventors have conducted intensive studies to achieve the above object, and as a result, the resin component is adhered to the surface of the elastic layer, and the resin component is not present on the surface. When the roller resistance in the case is R ₁ and the roller resistance when the resin component is present on the surface is R ₂ , the above resin component is adhered so as to give a relationship of log (R ₂ / R ₁ ) ≦ 3. , Can effectively prevent contamination of the latent image holding member (photoreceptor),
It has been found that a developing roller having low friction can be obtained.

In this case, as a means for giving the above resin component to the surface, a resin solution having a resin component concentration of 9% by weight or less such as a soluble nylon, an acrylic resin, a urethane-modified acrylic resin, a polycarbonate, a fluororesin, etc. It has been found that surface treatment with is effective.
Further, a silicone resin, a fluorine-based surfactant, a silicone-based surfactant, a silicone-based coupling agent, and a silica powder are selected from 100 parts by weight of the resin component.
It has been found that it is more effective to mix 1 to 100 parts by weight of the seed or two or more kinds.

That is, contamination of the photoreceptor tends to occur in a state where there is no developer between the surface of the developing roller and the surface of the photoreceptor, that is, in an initial state before use. To be effective, and in particular, soluble nylon, urethane-modified acrylic resin, polycarbonate,
Surface treatment with a fluororesin solution is effective for blocking contaminants from the elastic layer, and is further selected from silicone resins, fluorine-based surfactants, silicone-based surfactants, silicon-based coupling agents, and silica powder. 1
By containing the seed or two or more kinds, even in the case of forming an image by bringing the developing roller into contact with an image forming body such as a latent image holding member, it is possible to improve the drivability of the roller and the toner conveying property, In addition, it has been found that by optimizing the amount of developer charge on the roller surface, it is possible to obtain a high-quality image without density unevenness or background fogging, and that the image quality does not deteriorate even during long-term use. The present invention has been accomplished.

Accordingly, the present invention comprises forming a conductive elastic layer on the outer periphery of a highly conductive shaft, carrying a one-component developer on the surface of the elastic layer to form a thin layer of the developer. In the developing roller for supplying the developer, the elastic layer has a resin component on its surface, and a roller resistance when the elastic layer does not have the resin component is R ₁ , and a roller when the elastic layer has the resin component. Provided is a developing roller characterized by satisfying a relationship of log (R ₂ / R ₁ ) ≦ 3 when resistance is R ₂ .

According to the present invention, there is provided a developing device comprising a developing roller for supplying the one-component developer by rotating while the one-component developer is carried on the outer peripheral surface, wherein the developing roller is A developing device using the developing roller of the present invention is provided.

Hereinafter, the present invention will be described in more detail.
As shown in FIG. 1, the developing roller of the present invention has a conductive elastic layer 3 formed on the outer periphery of a good conductive shaft 2. In the present invention, the elastic layer is formed of a resin on its surface. When the roller resistance when the resin component is included and the resin component is not included is R ₁ , and the roller resistance when the resin component is included is R ₂ , the relationship of log (R ₂ / R ₁ ) ≦ 3 is obtained. It is configured to satisfy.

As the shaft 2, any shaft having good conductivity can be used, but usually, a metal core made of a metallic solid body and the inside thereof are hollowed out. A metal shaft such as a metal cylinder is used.

The elastic layer 3 formed on the outer periphery of the shaft 2 is made of an elastomer or a foam material such as polyurethane or EPDM as a base material, and is further provided with a conductive powder such as carbon black, metal or metal oxide powder. Also, by mixing an ionic conductive substance such as sodium perchlorate, the conductivity is adjusted to the optimum medium resistance region 10 ³ to
Those adjusted to 10 ¹⁰ Ωcm, particularly 10 ⁴ to 10 ⁸ Ωcm, are suitable.

In this case, the base material is polyurethane, natural rubber, butyl rubber, nitrile rubber, polyisoprene rubber,
Examples thereof include polybutadiene rubber, silicone rubber, styrene-butadiene rubber, ethylene-propylene rubber, chloroprene rubber, acrylic rubber, and mixtures thereof, with polyurethane and EPDM being particularly preferred.

First, regarding polyurethane, polyurethane elastomers and foam materials may be any of those produced by various methods. For example, a method in which carbon black is blended in a polyurethane prepolymer and the prepolymer is subjected to a crosslinking reaction. It can be obtained by a method such as a method in which a conductive material is blended and this polyol is reacted with a polyisocyanate by a one-shot method.

The urethane used as the base material of the elastic layer may be a polyhydroxyl compound such as a polyol used in the production of general flexible polyurethane foams or urethane elastomers, for example, polyether polyols and polyester polyols having a polyhydroxyl group at the end. And polyether polyols which are copolymers of the two, and polyolefin polyols such as polybutadiene polyols and polyisoprene polyols, and so-called polymer polyols obtained by polymerizing ethylenically unsaturated monomers in polyols. Typical polyols can be used. Examples of the polyisocyanate compound include polyisocyanates which are also used in general production of flexible polyurethane foams and urethane elastomers, that is, tridiisocyanate (TDI), crude T
DI, 4,4-diphenylmethane diisocyanate (M
DI), crude MDI, aliphatic polyisocyanates having 2 to 18 carbon atoms, alicyclic polyisocyanates having 4 to 15 carbon atoms, and mixtures or modified products of these polyisocyanates, for example, partially obtained by reacting with polyols. A prepolymer or the like is used.

On the other hand, EPDM is a terpolymer composed of ethylene, propylene and a third component in this case. The third component is not particularly limited, but may be dicyclopentadiene, ethylidene norbornene. , 1,4-hexadiene and the like are preferably used. Further, the ratio of the ethylene, propylene and the third component is as follows:
Although not particularly limited, the ethylene content is 5%.
~ 95 wt%, propylene content is 5 ~ 95 wt%,
It is preferable that the content of the third component is 0 to 50 in iodine value. Note that two or more types of EPDM having different iodine values can be used in combination. The above-mentioned EPDM may be used by blending silicone rubber or silicone-modified EPDM or both. In this case, the mixing amount of the silicone rubber and the silicone-modified EPDM is E
It can be 5 to 80 parts by weight based on 100 parts by weight of the PDM. The silicone-modified EPDM refers to a hybrid rubber in which the bonding force between both EPDM and silicone polymers is increased via a silanol compound or siloxane.

Further, a crosslinking agent and a vulcanizing agent can be added to crosslink the elastic layer into a rubbery substance. In this case, a vulcanization aid, a vulcanization accelerator, a vulcanization acceleration aid, a vulcanization retarder, and the like can be used in both cases of organic peroxide crosslinking and sulfur crosslinking. Furthermore, peptizing agents, foaming agents, plasticizers, softeners, tackifiers, antiblocking agents, separating agents, release agents, extenders, and coloring agents that are commonly used as rubber compounding agents in addition to the above. Etc. can be added.

The elastic layer mainly composed of polyurethane or EPDM is charged with various charged materials such as nigrosine, triaminophenylmethane and cationic dye for the purpose of controlling the amount of toner charge on the surface when used as a developing member. A fine powder such as a control agent, silicone resin, silicone rubber, or nylon can be added. in this case,
The amount of these additives is the same as that of the above polyurethane or EPD.
It is preferable that the charge control agent be 1 to 5 parts by weight and the fine powder be 1 to 10 parts by weight based on 100 parts by weight of M.

Examples of the conductive material include conductive carbon such as Ketjen Black EC and acetylene black, SAF, ISAF, HAF, and FE.
Rubber carbon such as F, GPF, SRF, FT, MT, etc.
Metals and metal oxides such as color (ink) carbon, pyrolytic carbon, natural graphite, artificial graphite, antimony-doped tin oxide, titanium oxide, zinc oxide, nickel, copper, silver, germanium, etc., which have been subjected to oxidation treatment, etc. ,
Examples thereof include conductive polymers such as polyaniline, polypyrrole, and polyacetylene. Among them, carbon black is inexpensive and easily controls conductivity in a small amount. Usually, 0.5 to 5 parts per 100 parts by weight of urethane.
It is preferably used in an amount of 0 parts by weight, particularly in the range of 1 to 30 parts by weight.

Examples of ion conductive substances include sodium perchlorate, lithium perchlorate, calcium perchlorate,
Inorganic ionic conductive materials such as lithium chloride and organic ionic conductive materials such as modified aliphatic dimethylammonium ethosulfate, stearyl ammonium acetate, lauryl ammonium acetate, octadecyltrimethylammonium perchlorate, tetrabutylammonium borate, etc. Is exemplified.

In the present invention, although the elastic layer 3 is not particularly limited, the resistance of the elastic layer 3 is 10 ³ to 10 ¹⁰ Ωcm, particularly 10 ⁴ to 1, depending on the blending of the carbon black.
It is preferable that the 0 ⁸ [Omega] cm. Resistance value is 10 ³ Ωcm
If it is less than the above, the electric charge may leak to the image forming body such as the photosensitive drum, or the developing roller itself may be broken by the voltage. On the other hand, if it exceeds 10 ¹⁰ Ωcm, the ground fogging tends to occur.

Although the hardness of the elastic layer 3 is not particularly limited, when the developing roller of the present invention is used in contact with an image forming body such as a photosensitive drum, the hardness is 60 ° on a JIS-A scale. Hereinafter, it is particularly preferable to set the angle to 25 to 55 °. In this case, if the hardness exceeds 60 °, the contact area with the photosensitive drum or the like becomes small, and good development may not be performed. On the other hand, if the hardness is too low, the compression set becomes large, and the development may be stopped for some reason. When the roller is deformed or decentered, the density of the image becomes uneven. For this reason, even when the hardness of the elastic layer is set to a low hardness, it is preferable to reduce the compression set as much as possible,
Specifically, it is preferably set to 20% or less. When the developing roller of the present invention is used in a non-contact proximity state with the image forming body, the hardness of the elastic layer 3 does not affect the obtained image.

Although the surface roughness of the elastic layer 3, that is, the surface roughness of the developing roller of the present invention is not particularly limited, the JIS 10-point average roughness is 15 μmRz or less, particularly 1 μmRz or less.
It is preferably set to 10 to 10 μmRz. Surface roughness is 15
If it exceeds μmRz, the thickness of the toner layer of the one-component developer (toner) and the uniformity of charging may be impaired.
By setting it to be not more than μmRz, the adhesion of the toner can be improved, and the image deterioration due to the wear of the roller during long-term use can be more reliably prevented.

As described above, the developing roller of the present invention has a roller resistance R ₁ when the elastic layer has a resin component on its surface and has no resin component, and has a roller resistance when the elastic layer has this resin component. when the roller resistance was R _2, which constitutes so as to satisfy the _{log (R 2 / R 1)} ≦ 3 the relationship, log (R ₂
/ R ₁ ) ≦ 3, more preferably log (R ₂ / R ₁ ) ≦ 2
By doing so, the object of the present invention can be achieved.

In this case, as a means for applying such a resin component to the surface of the elastic layer, a method of effectively treating the surface of the elastic layer with a resin solution is effectively employed. The concentration of the resin component in the resin solution is not particularly limited as long as the relationship of log (R ₂ / R ₁ ) ≦ 3 is satisfied, but the resin component concentration is 9% by weight or less, more preferably 5% by weight. The following is preferable. The type of the resin is also variously selected. In particular, when the toner is supplied while being in contact with an image forming body such as a photosensitive drum, it is preferable that the resin is non-staining to the image forming body. Specific examples thereof include soluble nylon, urethane-modified acrylic resin, acrylic resin, polycarbonate, fluororesin, and the like. One of these can be used alone, or two or more can be used in combination.

Here, the soluble nylon refers to a polymer which is soluble in a common organic solvent by copolymerizing a different polyamide unit with ordinary nylon 6, nylon 66, or the like, or chemically modifying an amide group. Nylon.

Many copolymerized nylons are made alcohol-soluble by terpolymerization, for example, 6/66/1.
2, 6/66/610/12, 6/610/11/12
Nylon and the like.

Examples of the modified nylon include N-methoxymethylated nylon and N-ethoxyethylated nylon in which the hydrogen atom of an amide group is substituted with an alkoxyl group.

The urethane-modified acrylic resin is obtained by introducing a urethane component into the acrylic resin to impart flexibility and flexibility.

As a method of modifying the acrylic resin with the urethane component, it is effective to chemically bond the urethane resin and the acrylic resin component from the viewpoint of compatibility, liquid stability, film flexibility and the like. . Specifically, a reaction between a polymer having a hydroxyl group introduced into an acrylic polymer by β-hydroxyethyl methacrylate and the like and a urethane prepolymer having an isocyanate group at a molecular terminal, or a molecular terminal as described below (one terminal or both terminals) ) Is synthesized by the reaction of an acrylic component having a hydroxyl group with a urethane prepolymer (A: acrylic acid, acrylate monomer or oligomer). In the polymer obtained in this manner, the urethane chain and the acrylic chain may be bonded to each other in a block type or in a graft type.

[0035]

Embedded image

The urethane-modified acrylic resin used in the present invention is not limited to the one obtained by the above-mentioned method. In addition, a method in which diisocyanate is added to an acrylic diol mixed system, a terminal isocyanate polyester as an acrylic monomer, It can also be obtained by adding polyether or the like and polymerizing the urethane acrylate. In addition, the acrylic resin component used for the synthesis includes a glass transition temperature T as a polymer.
g is preferably from room temperature to about 110 ° C.
-In addition to hydroxyethyl methacrylate, those containing, for example, ethyl methacrylate, isobutyl methacrylate, glycidyl methacrylate and the like are used. At this time, the composition of the acrylic component in the urethane-modified acrylic resin is 5 to 90% by weight, particularly 20 to 80% by weight.
It is particularly preferable that the content is 50 to 70% by weight.

The acrylic resin component may contain another monomer such as styrene in addition to the acrylic monomer.

When used in contact with an image forming body such as a photosensitive drum, a silicone component may be contained in the urethane-modified acrylic resin from the viewpoint of improving adhesion. Specifically, for example, a method of synthesizing by reacting a urethane prepolymer and an acrylic component using a polyol containing a silicone chain as a raw material can be considered.
In this case, the composition of the silicone component in the urethane prepolymer is preferably 2 to 80% by weight, particularly preferably 5 to 50% by weight. Further, the composition of the silicone component in the urethane-modified acrylic resin after the reaction is preferably 1 to 50% by weight, particularly preferably 3 to 30% by weight.

Examples of the polycarbonate used in the present invention include bisphenol A type represented by the following general formula (1) and a polymer having a structure represented by the following general formula (2) or (3) as a repeating unit. It is preferably used. Although the degree of polymerization is not particularly limited, it is generally 10 to 1000, preferably about 50 to 200.

[0040]

Embedded image(However, in formulas (2) and (3), R ₁, R_Two, R_Three, R _FourIs
A hydrogen atom or a substituted or unsubstituted carbon number of 1 to 10
Monovalent hydrocarbon group (aliphatic group, carbocyclic group or aromatic group)
And R _Five, R₆, R₇, R ₈, R ₉, R_Ten, R ₁₁, R₁₂
Is a hydrogen atom, a halogen atom, or substituted or unsubstituted
Represents a monovalent aliphatic group or a carbocyclic group having 1 to 10 carbon atoms
And Z is a substituted or unsubstituted carbon ring having 1 to 10 carbon atoms.
Or a group of atoms necessary for forming a heterocyclic ring. Also,
In the formulas (2) and (3), m is an integer of 0 to 10, n is 0 or
Is 1, and p of A and B is an integer of 1 to 10. )

Here, these polycarbonates are easily synthesized, for example, by reacting a diol compound represented by the following formula (4) with phosgene in a methylene chloride solution in the presence of an alkali.

[0042]

Embedded image

The structure of the polycarbonate used in the present invention is not limited to those described above, but may be a copolymer of these or a copolymer with another aliphatic or aromatic diol compound. .

Examples of the acrylic resin include polyacrylate, polymethyl methacrylate, polymethyl ethacrylate, those obtained by substituting their side chain terminals with a hydroxyalkyl group and the like, and copolymers thereof.

The fluororesin used in the present invention includes:
Polytetrafluoroethylene, polyvinylidene fluoride,
A common fluorine-containing polymer such as ethylene tetrafluoride-propylene hexafluoride copolymer is used, and a solvent-soluble fluororesin is particularly preferably used. Solvent-soluble fluororesins include vinylidene fluoride copolymers such as ternary copolymers of CH ₂ CF ₂ , C ₂ F ₄ and C ₃ F ₆ , C ₂ F ₄ , C ₂
Fluoroolefins such as F ₃ Cl and vinyl ethers,
Various copolymers such as copolymers of hydrocarbon olefins such as vinyl esters and vinyl silanes, copolymers of fluoroacrylates and acrylates, and polymers of diepoxy compounds substituted by perfluoroalkyl groups are used. Can be

These resins may be used alone as the resin component of the present invention, or may be used as a mixture with other resins.

Among these, soluble nylon and fluororesin are particularly preferably used from the viewpoint of reducing contamination and further reducing toner adhesion.

Although the roller surface can be reduced in friction to some extent by the above-mentioned surface treatment with the resin, especially when the roller is brought into contact with the image forming member for development, various additions are made to further reduce the friction. Agents can also be used. The present inventors have conducted intensive studies and found that as an additive capable of reducing friction, there is no contamination of an image forming body such as a photoreceptor or the like, without reducing the uniformity of surface treatment, and silicone resin, silicone resin powder, Fluorine and silicone surfactants, silicone coupling agents and silica powder have been found to be effective.

As the solvent-soluble silicone resin, for example, methyl silicone, methyl phenyl silicone, a modified product thereof, a silicone epoxy block copolymer and the like are used.

Examples of the silicone resin powder include fine powders of methyl silicone or methyl phenyl silicone polymer, and have an average particle diameter of 0.1 to 100 μm.
Are used.

Examples of the fluorinated surfactant include an ionic surfactant in which an alkyl fluoride is bonded to a carboxylic acid, a carboxylate, a sulfonate, or the like; an alkyl fluoride and an alcohol;
Examples include nonionic ones to which ethers and the like are bonded, and high molecular weight ones such as polymers and copolymers containing alkyl fluoride in the side chain and main chain.

Examples of the silicone-based surfactant include high molecular weight compounds such as a conjugate of a general silicone such as siloxane oxyethylene with a hydrophilic and lipophilic segment, and a copolymer of a methyl silicone and an acrylic segment. Things.

Examples of the silicon-based coupling agent include not only a normal silane coupling agent but also an amino group at the terminal.
Includes silanes into which isocyanate groups, vinyl groups, etc. have been introduced.

These may be used alone or in combination of two or more. In addition, a fluororesin is also suitably used as an additive. The additive is used in an amount of 1 to 100 parts by weight, preferably 1 to 100 parts by weight of the resin component.
0 to 75 parts by weight.

Further, the above-mentioned processing liquid may contain a conductive powder such as the above-mentioned carbon black or an ionic conductive substance, if necessary. The amount of the conductive powder or ionic conductive substance to be added is 0.1 to 100 parts by weight of the resin component.
It is preferably from 001 to 1 part by weight.

As the surface treatment, after preparing a treatment solution,
It can be performed by a spray method, a roll coater method, a dipping method, or the like. For example, surface treatment by dipping is usually performed at room temperature for 5 seconds to 5
Immersion for 10 minutes to 1 minute,
A drying method can be employed. When the spray method is adopted, the concentration of the resin in the treatment liquid can be set higher than that of the dipping method. For example, a resin whose concentration is adjusted to 10 to 30% can be used.
If the resin component can be applied to the surface of the elastic layer so that (R ₂ / R ₁ ) ≦ 3, the object of the present invention can be achieved.

The solvent for preparing the resin solution may be any solvent as long as it dissolves the above resin. Usually, lower solvents such as methanol, ethanol and isopropanol, and ketones such as acetone, methyl ethyl ketone and cyclohexanone are used. , Toluene, xylene and the like are preferably used.

In this case, it is considered that a uniform coating layer is not formed by the above resins on the surface of the developing roller subjected to the above surface treatment, and that the elastic layer is polished in some places. This means that the SEM
The roller resistance can be easily determined by observing at, and in the measurement of roller resistance, if a uniform film is originally formed on the elastic layer, the roller resistance should rise sharply in proportion to the concentration of the treated resin. However, when the roller treated with the resin concentration of the present invention is treated with, for example, copolymerized nylon, as shown in FIG. 3, the resistance gradually increases up to a concentration of 6 to 7% by weight, and then increases sharply. This is to be expected from the fact that it shows a tendency to do so.

Therefore, as described above, in the surface treatment of the present invention, when the surface is usually treated on a smooth surface, unlike the case where a uniform coating layer of several microns is formed, the surface of the elastic layer is irregularly formed. A resin is attached to the surface to improve the surface characteristics while maintaining the roughness of the elastic layer.

The developing roller of the present invention can be incorporated in an ordinary developing device using a one-component developer. Specifically, as shown in FIG. The developing roller 1 of the present invention is disposed between the photosensitive drum 5 holding the electrostatic latent image and the toner 6 is supplied to the developing roller 1 by the toner coating roller 4, and the toner 6 is uniformly thinned by the layering blade 7. The toner is supplied to the photosensitive drum 5 from the thin layer, and the toner is adhered to the electrostatic latent image on the photosensitive drum 5 to visualize the latent image. In this case, the photosensitive drum 5 and the developing roller 1 of the present invention may be in a contact state or a close state separated by a predetermined distance. According to the developing roller 1 of the present invention, such a non-contact Even when used in a state, it prevents the adhesion of the developer and improves the uniformity of charging of the developer,
A high-quality image free from uneven density and background fog can be reliably obtained, and furthermore, it is possible to prevent the deterioration of the image quality in long-term use as much as possible. Note that FIG.
Is described in the prior art, and the description is omitted.

Here, the developing roller of the present invention is preferably used when a developer is supplied to a latent image holding member such as a photosensitive drum holding an electrostatic latent image to visualize the electrostatic latent image. However, the toner is preferably used as a toner supply member for forming an image by supplying toner directly to a recording medium such as paper while controlling using a control electrode.

As an image forming mechanism using such a toner supply body, for example, as shown in FIG. 4, a toner supply roller (toner supply body) 11 carries toner 15 from a toner application roller 14 on a surface thereof. The toner 15 on the surface of the toner supply roller 11 is formed into a uniform thin layer by a stratification blade 16, and is rotated by the rotation of the toner supply roller 11 to form a large number of small holes 18 (only one is shown in the drawing) through which the toner passes. Is formed, and is brought into contact with or close to one surface side of an electrode body 17 provided with a control electrode (not shown) for controlling the passage of toner for each of the small holes 18.
On the surface of the image forming body 19 such as paper placed on the other side of
An image forming apparatus that forms an image with toner on the surface of the image forming body 19 by flying and supplying the toner 15 through the small holes 18 can be exemplified (for example, Japanese Patent Application Laid-Open No. 8-129293). The roller of the present invention can be suitably used as the toner supply roller 11 of such an image forming mechanism. In the figure, reference numeral 20 denotes a back electrode for attracting the toner 15 to the image forming body 19 side. In the figure, the toner supply roller 11 and the electrode body 17 are separated from each other, and the toner supply roller 11 and the toner application roller 14 are separated from each other. Or in a state of contact. Further, FIG. 4 shows paper sheets such as paper, OHP paper, and photographic paper as the image forming body 19, but this image forming body 19 is a drum,
An image forming body other than paper sheets such as a belt may be used.

[0063]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, the surface treatment was performed by immersing in a treatment solution at room temperature for 30 seconds.

Example 1 Glycerin was added with propylene oxide and ethylene oxide to give a molecular weight of 500
100 parts by weight of polyether polyol (Exenol 828 from Asahi Glass Co., Ltd.) (OH value: 33) (parts by weight,
The same applies hereinafter), 1.0 part of 1,4-butanediol, and a silicone surfactant (L-520, manufactured by Nippon Yunika).
5 parts, 0.5 part of nickel acetylacetonate, 0.01 part of dibutyltin dilaurate and 2.0 parts of acetylene black (manufactured by Denka Co., pH 6.9) are added, and the mixture is preliminarily mixed using a mixer and then painted. Acetylene black was uniformly dispersed by kneading with a roll to prepare a polyol composition.

The polyol composition was stirred under reduced pressure to remove bubbles, and then 17.5 parts of urethane-modified MDI (Sumijur PF, manufactured by Sumitomo Bayer Urethane Co., Ltd.) was added thereto.
Stir for a minute and then pour into a mold heated to 110 ° C.
After curing for 2 hours, an elastic layer was formed on the outer periphery of the metallic shaft to obtain a roller having the structure shown in FIG. The surface of the obtained roller is polished and the surface is JIS10-point average roughness 7 μmR
Adjusted to z, a developing roller was prepared.

Next, the developing roller was washed with 3% by weight of soluble nylon (CM8000, manufactured by Toray Industries, Inc.) in methanol.
Immerse in the dissolved solution, pull it up, dry it,
Surface treatment was performed.

Example 2 3.32 parts of acetylene black was blended with 100 parts of a polyisoprene polyol having a molecular weight of 2500 (OH value = 47.1) and stirred for 30 minutes. Thereafter, 13.33 parts of Glue MDI (NCO% = 31.7) and 0.001 part of dibutyltin dilaurate were added, followed by stirring for 3 minutes. Next, a shaft was arranged, and this reaction mixture was poured into a mold heated to 90 ° C. in advance, and a curing reaction was performed at 90 ° C. for 12 hours to obtain a roller.

The surface of the obtained roller is polished to JIS10.
The point average roughness was adjusted to 7 μmRz to form a developing roller.

Next, the developing roller is solvent-soluble fluororesin (Velflon 1000, manufactured by NOF CORPORATION) in toluene.
Was immersed in a solution in which 5% by weight was dissolved, pulled up and dried to perform a surface treatment.

Example 3 Instead of a soluble nylon solution, polymethyl methacrylate (Dianal LR177,
The same operation as in Example 1 was performed except that the surface treatment was performed using a 3% by weight toluene / methyl ethyl ketone solution (manufactured by Mitsubishi Rayon Co., Ltd.).

Example 4 100 parts of EPDM (EP33, manufactured by Nippon Synthetic Rubber Co., Ltd.) was added to ISAF carbon 25
Parts, 5 parts of zinc white, 1 part of stearic acid, and 1 part of dicumyl peroxide were mixed by a roll mill, the mixture was wound around the outer periphery of a metal shaft, and 100 kg / cm ² in a mold preheated to 150 ° C. A roller having the structure shown in FIG. 1 was obtained by molding under pressure for 30 minutes, and the surface thereof was polished, and the JIS 10-point average roughness was set to 7 μmRz.

Next, the developing roller was immersed in a solution of polycarbonate (Z200, manufactured by Mitsubishi Gas Chemical Co., Ltd.) at a concentration of 3% by weight in toluene, pulled up, dried and subjected to a surface treatment. .

[Example 5] In Example 1, 50 parts of a solvent-soluble fluororesin (Nippon Yushi, Belflon) was added to 100 parts of the soluble nylon in the soluble nylon solution, and the surface treatment was performed in the same manner. .

Example 6 In Example 1, 200 parts of silicone resin fine particles (Tospearl 240, manufactured by Toshiba Silicon) were added to 100 parts of soluble nylon, and the surface treatment was performed in the same manner.

[Example 7] In Example 1, 5 parts of a silicone-based surfactant (manufactured by NOF CORPORATION, Modiper FS710) was added to 100 parts of the soluble nylon at a solid content.
Surface treatment was performed similarly.

Example 8 In Example 1, 10 parts of positively charged silica H2050EP (manufactured by Hexus Japan) was added to 100 parts of soluble nylon, and the surface treatment was performed in the same manner.

Example 9 A developing roller was obtained in the same manner as in Example 3 except that 50 parts of silicone rubber (manufactured by Nippon Synthetic Rubber Co., Ltd., EH5250U) was added to 100 parts of EPDM. Next, the developing roller was mixed with toluene / methyl ethyl ketone / isopropyl alcohol at 3% by weight of a urethane-modified acrylic resin (EAU8B, manufactured by Asia Industry Co., Ltd.).
It was immersed in a solution in which the concentration and sodium perchlorate were dissolved at a concentration of 0.3% by weight, pulled up, dried and subjected to a surface treatment.

[Comparative Example 1] In Example 1, the developing roller before forming the surface coating layer was used as an evaluation sample.

Comparative Example 2 A coating layer having a thickness of about 10 μm was formed on the surface of Example 1 by using a 12% by weight methanol solution of soluble nylon.

[Comparative Example 3] In Example 1, 2% by weight of polyvinyl chloride (Eslec E, manufactured by Sekisui Chemical Co., Ltd.)
Surface treatment was performed using the solution.

The following characteristic tests were performed on the developing rollers obtained in the above Examples and Comparative Examples. Table 1 shows the results. (1) Roller resistance Each roller was pressed against the copper plate with a load of 500 g at both ends, and the resistance was measured using a resistivity meter R8340A (manufactured by Advantest).
The measurement was performed by applying a voltage of V. (2) Surface roughness For each roller, a surface roughness meter Handy Surf E-30
It was measured using a type A (manufactured by Tokyo Seimitsu Co., Ltd.). (3) Toner charge amount Each roller is mounted on the developing unit shown in FIG. 2 as a developing roller and rotated at a peripheral speed of 50 mm / sec to form a uniform thin toner layer on the surface of the developing roller. The layer was sucked with air and introduced into a Faraday gauge, and the charge amount was measured. (4) Image Output Each roller is mounted as a developing roller 1 on the developing unit shown in FIG. 2 in a non-contact and non-contact state with the photosensitive drum 5, and a linear velocity is determined using a non-magnetic one-component toner having an average particle diameter of 7 μm. 60m
An image was formed by reversal development while rotating at a peripheral speed of m / sec, and the image quality (sharpness and density uniformity) at the initial stage and after 2,000 prints, fog, and generation of toner dust were evaluated. Table 1 shows the results. Further, in Example 1, the roller resistance was measured when the resin concentration was variously changed. The results are shown in FIG.

[0082]

[Table 1]

Each of the above rollers is mounted as a toner supply roller 11 on the image forming unit shown in FIG. 4, and an image is formed while conveying an image forming body (plain paper) at a linear speed of 60 mm / sec. After 2000 prints, fog and toner dust on the image were evaluated. At the same time, the state of toner filming on the roller surface after 2,000 prints was also observed. Table 2 shows the results.

[0084]

[Table 2]

[0085]

According to the developing roller of the present invention, it is possible to obtain a high-quality image free from inconsistencies such as contamination of a photoreceptor and the like and without uneven density and background fogging. Also, the image quality does not deteriorate.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a developing roller of the present invention.

FIG. 2 is a schematic sectional view showing an example of the developing device of the present invention.

FIG. 3 is a graph showing a relationship between a resin concentration by a surface treatment and a roller resistance.

FIG. 4 is a schematic sectional view showing another example of the developing device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing roller 11 Toner supply roller 2 Shaft 3 Elastic body 4, 14 Toner application roller 5 Photosensitive drum (latent image holding body) 6, 15 Toner (nonmagnetic one-component developer) 7, 16 Layering blade 8 Transfer part 9 Cleaning part DESCRIPTION OF SYMBOLS 10 Cleaning blade 17 Electrode body 18 Small hole 19 Paper sheet (image forming body) 20 Back electrode

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Taro Miyamoto 3-5-610 Ogawa Higashicho, Kodaira City, Tokyo (72) Inventor Manabu Yakushiji 3-3-5-612 Ogawa Higashicho, Kodaira City, Tokyo (72) Inventor Takahiro Kawagoe 1302-57 Aobadai, Tokorozawa, Saitama

Claims (7)

[Claims] An elastic layer having conductivity is formed on the outer periphery of a good conductive shaft, and a one-component developer is carried on the surface of the elastic layer to form a thin layer of the developer. Wherein the elastic layer has a resin component on its surface, and the roller resistance when the resin layer does not have this resin component is R ₁ , and the roller resistance when the resin layer has this resin component is R ₂ . A developing roller that satisfies the following relationship: log (R ₂ / R ₁ ) ≦ 3. 2. The developing roller according to claim 1, wherein the resin component is at least one member selected from the group consisting of soluble nylon, acrylic resin, urethane-modified acrylic resin, polycarbonate, and fluororesin. 3. The resin component further comprises a silicone resin,
One or more selected from a fluorine-based surfactant, a silicone-based surfactant, a silicone-based coupling agent, and silica powder are used in an amount of 1 to 1 based on 100 parts by weight of the resin component.
3. The developing roller according to claim 1, wherein the developing roller is added in an amount of 00 parts by weight. 4. The developing roller according to claim 1, wherein a conductive substance is added to said resin component. 5. The developing device according to claim 1, wherein said elastic layer is surface-treated by immersing its surface in a resin solution having a resin component concentration of 9% by weight or less. roller. 6. The developing roller according to claim 1, wherein said elastic layer is mainly composed of a polyurethane elastomer or EPDM. 7. A developing device comprising a developing roller for supplying the one-component developer by rotating the outer peripheral surface while the one-component developer is carried thereon, wherein the developing roller is used as the developing roller. A developing device using the developing roller according to any one of the preceding claims.