JP2021099439A - Developing roller and image forming apparatus - Google Patents

Abstract

To provide a developing roller that can prevent fogging under a high-temperature and high-humidity condition and provide a high-quality image, and a developing device and an image forming apparatus using the developing roller.SOLUTION: A developing roller comprises: a shaft body 2; an elastic layer 3 provided on an outer surface of the shaft body 2; and a coating layer 4 provided on the outside of the elastic layer 3. The coating layer 4 includes a resin having a urethane bond formed of polyol and isocyanate in a constitutional unit, a first surface roughness agent composed of organic metal compound particles, and a second surface roughness agent composed of fine particles other than the organic metal compound particles. The first surface roughness agent has an average particle diameter of 2 μm or less. The average particle diameter of the first surface roughness agent and the average particle diameter of the second surface roughness agent satisfy the relationship of the average particle diameter of the first surface roughness agent≤the average particle diameter of the second surface roughness agent.SELECTED DRAWING: Figure 1

Description

The present invention relates to a developing roller and an image forming apparatus.

A developing roller used in an image forming apparatus such as a copying machine, a printer, or a facsimile that employs an electrophotographic method has a function of imparting a uniform frictional charge to toner and stably transporting a predetermined amount of toner to a developing region. Has. Therefore, by incorporating fine particles into the surface layer of the developing roller, the surface is provided with fine irregularities due to the particles. However, in the process of responding to the speeding up, longevity, and high image quality of electrophotographic devices in recent years, toner has also evolved, and the electrical characteristics of various materials that make up the developing roller have been adjusted, thereby adjusting the electrical characteristics of the developing roller. It is being studied to improve the transportability of the developer.

In an image forming apparatus that employs an electrophotographic method, in particular, when a large amount of image is output from the initial stage, the temperature and humidity become high, insufficient charging occurs, and the developer is developed on a white background of the image. , Also called "fog") may occur.

Therefore, for the purpose of preventing the occurrence of afterimages or improving fog, for example, Patent Document 1 describes at least a material constituting the surface by imparting excellent negative chargeability to the toner and reducing the resistance. A developing roller containing a quaternary ammonium base-containing copolymer is disclosed.

Japanese Unexamined Patent Publication No. 2001-31136

However, there is still room for improvement in preventing fogging under high temperature and high humidity conditions in order to cope with high speed and high image quality of the electrophotographic apparatus.
The present invention has been made in view of the above circumstances, and is a developing roller capable of suppressing fog under high temperature and high humidity conditions and providing a high-quality image, and an image forming apparatus using the developing roller. The purpose is to provide.

The present inventors have found that fogging under high temperature and high humidity conditions can be solved by compensating for the insufficient charge from the initial stage and adjusting the charge imparting property of the particles forming the convex portion of the developing roller to the toner. The present invention has been reached.
That is, the present invention is a developing roller including a shaft body, an elastic layer provided on the outer surface of the shaft body, and a coating layer provided outside the elastic layer, and the coating layer is a urethane bond made of polyol and isocyanate. The average particle of the first surface roughness agent, which comprises a resin having a constituent unit, a first surface roughness agent composed of organic metal compound particles, and a second surface roughness agent composed of fine particles other than the organic metal compound particles. A developing roller having a diameter of 2 μm or less and having an average particle diameter of the first surface roughness agent and an average particle diameter of the second surface roughness agent satisfying the following relationship.
Average particle size of the first surface roughness agent ≤ Average particle size of the second surface roughness agent

The resistance value on the surface of the developing roller ^{is preferably 1 × 10 6} Ω or more and 9 × 10 ⁹ Ω or less.

The organometallic compound particles are preferably hydroxybenzoic acid metal compounds.

The hexadecane contact angle on the surface of the developing roller is preferably 30 ° or more.

The image forming apparatus of the present invention includes the developing roller of the present invention.

According to the developing roller and the image forming apparatus of the present invention, it is possible to suppress the occurrence of fog under high temperature and high humidity conditions and provide a high quality image.

It is a perspective view which shows one Embodiment of the developing roller of this invention. It is a schematic diagram for demonstrating the surface of the developing roller of this invention. It is a schematic cross-sectional view which shows one Embodiment of the image forming apparatus of this invention. It is a front view which shows the apparatus which measures the resistance of the surface of a developing roller.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[Development roller]
As shown in FIG. 1, the developing roller 1 of the present invention includes a shaft body 2, an elastic layer 3 provided on the outer surface of the shaft body 2, and a coating layer 4 provided outside the elastic layer 3.
The coating layer 4 contains a resin having a urethane bond of polyol and isocyanate as a constituent unit, a first surface roughness agent composed of organic metal compound particles, and a second surface roughness agent composed of fine particles other than the organic metal compound particles. , The average particle size of the first surface roughness agent is 2 μm or less, and the average particle size of the first surface roughness agent and the average particle size of the second surface roughness agent have the following relationship. It meets.
Average particle size of the first surface roughness agent ≤ Average particle size of the second surface roughness agent The details of each configuration will be described below.

<Axis body>
As the shaft body 2, preferably, a shaft body having a conductive property and used for a conventionally known developing roller can be used. The shaft body 2 is preferably composed of at least one metal selected from the group consisting of, for example, iron, aluminum, stainless steel, and brass. It should be noted that such a shaft body 2 is also generally known by the name of "core metal".

The shaft body 2 may contain an insulating resin. The insulating resin may be, for example, a thermoplastic resin or a thermosetting resin. The shaft body 2 may include, for example, a core body made of an insulating resin and a plating layer provided on the core body. Such a shaft body 2 can be obtained, for example, by plating a core body made of an insulating resin to make it conductive.
The shaft body 2 is preferably a core metal in order to obtain good conductive properties.

The shape of the shaft body 2 is preferably, for example, a rod shape, a tubular shape, or the like. The cross-sectional shape of the shaft body 2 may be, for example, a circular shape, an elliptical shape, or a non-circular shape such as a polygon. The outer peripheral surface of the shaft body 2 may be subjected to treatments such as cleaning treatment, degreasing treatment, and primer treatment.

The axial length of the shaft body 2 is not particularly limited, and may be appropriately adjusted according to the form of the image forming apparatus to be installed. Further, the diameter of the shaft body 2 (diameter of the circumscribed circle) is not particularly limited, and may be appropriately adjusted according to the form of the image forming apparatus to be installed.

<Elastic layer>
The elastic layer 3 develops hardness and elasticity that can be pressed against the photoconductor with an appropriate nip width and nip pressure so that toner can be supplied to the electrostatic latent image formed on the surface of the photoconductor in just proportion. It is provided to be applied to the roller 1. Various rubber materials can be used for the elastic layer 3. The rubber used for the rubber material includes ethylene-propylene-diene copolymer rubber (EPDM), acrylic nitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), and styrene-. Examples thereof include butadiene rubber (SBR), fluororubber, silicone rubber, epichlorohydrin rubber, hydride of NBR, and urethane rubber. These can be used alone or in combination of two or more. Among these, silicone rubber having a small compressive stress strain due to pressing is preferable. Examples of the silicone rubber include polydimethylsiloxane, polymethyltrifluoropropylsiloxane, polymethylvinylsiloxane, polyphenylvinylsiloxane, and copolymers of these siloxanes.

By blending a conductivity-imparting agent such as an electronically conductive substance or an ionic conductive substance in the elastic layer 3, the conductivity thereof can be appropriately adjusted. Examples of the electronically conductive substance include conductive carbon such as Ketjen Black EC and acetylene black, carbon for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT, and oxidized color (ink). Examples thereof include metals such as carbon, copper, silver and germanium, and metal oxides thereof. Among these, carbon black (conductive carbon, carbon for rubber, carbon for color (ink)) is preferable because it is easy to control the conductivity with a small amount. Examples of the ion conductive substances include inorganic ion conductive substances such as sodium perchlorate, lithium perchlorate, calcium perchlorate, lithium chloride, lithium bisimide, and potassium bisimide, and modified aliphatic dimethylammonium etosulfate. Examples thereof include organic ion conductive substances such as stearyl ammonium acetate. Reactive ether-modified silicone oil may be added to the elastic layer 3.

<Coating layer>
FIG. 2 shows a side view of the developing roller 1. The coating layer 4 is a resin having a urethane bond of polyol and isocyanate as a constituent unit, a first surface roughness agent 8 composed of organic metal compound particles, and a second surface roughness agent composed of fine particles other than the organic metal compound particles. 7 is included.
Note that FIG. 2 schematically shows the surface state of the coating layer 4, particularly the state in which the first surface roughness agent 8 and the second surface roughness agent 7 are dispersed.

(Binder resin)
The coating layer 4 contains, as a binder resin, a resin having a urethane bond of polyol and isocyanate as a constituent unit, that is, a polyurethane resin.
The polyol component is not particularly limited, but a polyether polyol, a polyester polyol, a polycarbonate polyol, a polybutadiene polyol, a polyisoprene polyol, an acrylic polyol, a silicone-modified polyol, and a fluorine-modified polyol can be used. The isocyanate compound to be reacted with these polyol components is not particularly limited, but is limited to ethylene diisocyanate, aliphatic polyisocyanate such as 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and cyclohexane. Alicyclic polyisocyanates such as 1,3-diisocyanate, cyclohexane 1,4-diisocyanate, aromatic isocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI) and These copolymers and blocks thereof can be used.

(Surface roughness material)
As shown in FIG. 2, the developing roller 1 of the present invention contains a first surface roughness agent 8 made of organic metal compound particles and a second surface roughness agent 7 made of fine particles other than organic metal compound particles. The average particle size of the surface roughness agent 8 of 1 and the average particle size 7 of the second surface roughness agent satisfy the following relationship.
Average particle size of the first surface roughness agent ≤ average particle size of the second surface roughness agent The average particle size of the first surface roughness agent 8 and the second surface roughness agent 7 has the above relationship. As a result, as shown in FIG. 2, the surface of the second surface roughness agent 7 protrudes from the surface of the first surface roughness agent 8 or becomes at the same level. Since the surface of the coating layer 4 has such a structure, toner can be satisfactorily conveyed while improving triboelectric charging.

-First surface roughness agent-
As the organometallic compound of the organometallic compound particles, a hydroxybenzoate metal compound is preferable. As the metal, Fe, Zn, Al, Mg, Ca, Ti, Zr, Cr, strontium (Sr), Cu, Li, Bi and the like are preferable.
The hydroxybenzoic acid metal compound is added because the effect of attracting electrons on the carboxyl group side of benzoic acid and the effect of donating electrons on the phenoxy side having a hydroxyl group are combined to exhibit the effect of electron transition with the aromatic ring. As a result, during triboelectric charging, the characteristic that the charge rises faster and the potential rises are observed.
The size of the organometallic compound particles is preferably 7 μm or less, more preferably 3 μm or less, still more preferably 2 μm or less, in consideration of the thickness of the coating layer 4.
Here, the average particle size of the organic metal compound compound is the volume average particle size (laser diffraction / scattering type particle size measurement method) of the primary particles. The volume average particle size can be measured with a laser particle size distribution measuring machine such as a laser micron sizer (manufactured by Seishin Enterprise Co., Ltd.).

-Second surface roughness agent-
The second surface roughness agent 7 is fine particles other than the first surface roughness agent 8, and includes metal oxide particles, inorganic particles such as silica (including surface-treated silica), and carbon particles for coloring. Resin particles such as acrylic, urethane, nylon, acrylic nitrile, silicone, silicone rubber, and benzoguanamine. The coating layer 4 may contain only one type of the second surface roughness agent 7, or may contain two or more types of the second surface roughness agent 7.
The relationship between the average particle size of the first surface roughness agent and the average particle size of the second surface roughness agent is the average particle size of the first surface roughness agent ≤ the average particle size of the second surface roughness agent. As shown in 2, it is dispersed in the valley between the first surface roughness agents 8. Therefore, even if the organic metal compound particles which are the first surface roughness agent and the primary particle diameter of the second surface roughness agent are the same size, the particles of the second surface roughness agent 7 are aggregated. As a result, the large particles become the second surface roughness agent 7, and the small particles become the first surface roughness agent 8.

The size of the second surface roughness agent 7 is an average particle diameter of 2 μm or more, preferably 3 μm or more and 15 μm or less. By setting the average particle size of the second surface roughness agent 7 in the above range, the print quality can be improved. When the average particle size is 2 μm, it is easy to aggregate and it is not completely dispersed before coating.
The average particle size (secondary particles) of the second surface roughness agent can be measured with a particle size distribution measuring device (manufactured by Beckman Coulter).

The thickness of the coating layer 4 is preferably 5 μm or more and 13 μm or less, and more preferably 6 μm or more and 11 μm or less.
Here, the thickness of the coating layer is the thickness of the portion where the coating layer is cut in the direction perpendicular to the axis and the surface roughness agent is not present.

(Other configurations)
The developing roller 1 of the present invention may include an adhesive layer between the shaft body 2 and the elastic layer 3 and between the elastic layer 3 and the coating layer 4. Here, particularly for the adhesive layer provided between the elastic layer 3 and the coating layer 4, the electrical characteristics of the developing roller 1 can be adjusted by adjusting the electrical characteristics of the adhesive layer. , The developing performance of the developing roller 1 as a developing roller can be satisfactorily adjusted.

In the developing roller 1 of the present invention, the relative permittivity of the adhesive layer is 1 or more and 10 or less at 100 Hz, and 1000 or more and 10000 or less at 0.01 Hz. By adjusting the relative permittivity of the adhesive layer within this range, even if the relative permittivity of the coating layer 4 is adjusted to be low in order to satisfactorily suppress the occurrence of filming, the developer can be supported or supplied. The capacitance can be secured, and the developer can be stably charged. Therefore, it is possible to suppress a decrease in print density during printing. The relative permittivity of the adhesive layer is preferably 4.0 or more and 10.0 or less at 100 Hz, and preferably 2000 or more and 5000 or less at 0.01 Hz.

The adhesive layer preferably contains an organic titanium compound and / or an organic zirconium compound, and more preferably contains these organic metal compounds and a silane coupling agent. By using the organic titanium compound and the organic zirconium compound in combination with the silane coupling agent, the relative permittivity of the elastic layer 3 is increased to maintain good development performance, and the elastic layer 3 and the coating layer 4 are combined. The adhesiveness can be improved. Examples of the organic titanium compound include a titanium compound containing an alkoxy group, a titanium chelate compound and the like, and examples of the organic zirconium compound include a zirconium compound containing an alkoxy group and a zirconium chelate compound. As these organic titanium compounds and organic zirconium compounds, commercially available ones can be appropriately used.

(Resistance value on the surface of the developing roller)
The resistance value of the surface of the developing roller 1 ^{is selected so that the resistance value is 9 × 109} or less by the combination of polyol and isocyanate, and if necessary, an ionic conductive material, sodium perchlorate, lithium perchlorate, and excess. ^{Adjust the resistance value to 1 × 10 7} Ω or more and 1 × 10 E ⁹ Ω or less with calcium chlorate, lithium chloride, lithium bisimide, potassium bisimide, etc., or ionic liquid pyridium type, imidazole type, quaternary ammonium type, etc. Is possible. However, basically, the resistance value of electron conductivity by carbon varies depending on the dispersion conditions and is in a range where it is difficult to adjust, so it is preferable to use an ionic conductivity mechanism. When the resistance value is 1 × 10 ⁶ Ω or more, the resistance value can be easily adjusted with the ionic conductive material, and when the resistance value is 9 × 10 ⁹ Ω or less, the occurrence of fog can be satisfactorily prevented.

(Charging amount Q / M)
The amount of charge (Q / M; μC / g) is preferably 15 or more and 25 or less. When the amount of charge is in the above range, the potential is sufficient, the toner does not scatter during transfer, and the occurrence of fog can be prevented, so that a high-quality image can be obtained.

(Hexadecane contact angle)
The hexadecane contact angle on the surface of the developing roller 1 is preferably 30 ° or more, more preferably 45 ° or more, and further preferably 50 ° or more. When the temperature is 30 ° or more, the occurrence of filming can be satisfactorily suppressed. By suppressing filming, the life of the developing roller 1 is extended, which leads to stabilization of image quality. In addition, fog generation due to filming can be suppressed.
The hexadecane contact angle can be measured using a portable contact angle meter PCA-1 (manufactured by Kyowa Interface Science Co., Ltd.).

By containing an organometallic compound in the coating layer 4, the developing roller 1 of the present invention can compensate for the initial insufficient charge and adjust the resistance value on the surface of the developing roller 1, so that the image quality is improved and the temperature is hard. The fog under the conditions can be resolved.

[Developer and image forming device]
The developing roller 1 of the present invention can be suitably used as a developing agent carrier in a developing device and an image forming device. In the present embodiment, the configuration other than the developing roller 1 in the image forming apparatus is not particularly limited. An example of the developing apparatus and the image forming apparatus 10 provided with the developing roller 1 of the present invention will be described with reference to FIG.

The image forming apparatus 10 connects a plurality of image carriers 11B, 11C, 11M and 11Y mounted on the developing units B, C, M and Y of each color (black, cyan, magenta, yellow) in series on the transfer transfer belt 6. It is a tandem type color image forming apparatus arranged in, and development units B, C, M and Y are arranged in series on a transfer transfer belt 6. The developing unit B carries an image via an image carrier 11B, for example, a photoconductor (also referred to as a photosensitive drum), a charging means 12B, for example, a charging roller, an exposure means 13B, a developing device 20B, and a transfer transfer belt 6. A transfer means 14B that comes into contact with the body 11B, for example, a transfer roller and a cleaning means 15B are provided.

The developing device 20B is an example of the developing device of the present invention, and includes the developing roller 1 of the present invention and the developing agent 22B as shown in FIG. Therefore, in the image forming apparatus 10, the developing roller 1 is mounted as the developing agent carriers 23B, 23C, 23M and 23Y. Specifically, the developing apparatus 20B includes a housing 21B for accommodating a one-component non-magnetic developer 22B, a developing agent carrier 23B for supplying the developing agent 22B to the image carrier 11B, and a developing agent carrier 23B. A toner supply roller 25B for supplying the developer 22B and a developer amount adjusting means 24B for adjusting the thickness of the developer 22B, for example, a blade are provided. In the developing apparatus 20B, the developer amount adjusting means 24B is in contact with or pressure-contacted with the outer peripheral surface of the developer carrier 23B as shown in FIG. That is, the developing device 20B is a "contact developing device". The developing units C, M and Y are basically configured in the same manner as the developing unit B, and the same elements are designated by the same reference numerals and symbols C, M or Y indicating each unit, and the description thereof will be omitted. ..

In the image forming apparatus 10, the developer carrier 23B of the developing apparatus 20B is arranged so that its surface is in contact with or pressure-contacted with the surface of the image carrier 11B. Similar to the developing device 20B, the developing devices 20C, 20M and 20Y are also arranged so that the surface of the developing devices 23C, 23M and 23Y is in contact with or pressed against the surfaces of the image carriers 11C, 11M and 11Y. .. That is, the image forming apparatus 10 is a "contact type image forming apparatus".

The fixing means 30 is arranged on the downstream side of the developing unit Y. The fixing means 30 includes a fixing roller 31, an endless belt support roller 33 arranged in the vicinity of the fixing roller 31, a fixing roller 31, and an endless belt in a housing 34 having an opening 35 through which the recording body 16 is passed. An endless belt 36 wound around the support roller 33 and a pressure roller 32 arranged to face the fixing roller 31 are provided, and the fixing roller 31 and the pressure roller 32 are in contact with each other or pressure contacted with each other via the endless belt 36. It is a pressure heat fixing device that is rotatably supported so as to perform. A cassette 41 for accommodating the recording body 16 is installed at the bottom of the image forming apparatus 10. The transfer transfer belt 6 is wound around a plurality of support rollers 42.

The developing agents 22B, 22C, 22M and 22Y used in the image forming apparatus 10 may be either a dry developing agent or a wet developing agent as long as they can be charged by friction, and may be a non-magnetic developing agent or magnetic developing. It may be an agent. In the housings 21B, 21C, 21M and 21Y of the developing units B, C, M and Y, one component non-magnetic black developer 22B, cyan developer 22C, magenta developer 22M and yellow developer 22Y are contained. Each is stored.

The image forming apparatus 10 forms a color image on the recording body 16 as follows. First, in the developing unit B, an electrostatic latent image is formed on the surface of the image carrier 11B charged by the charging means 12B by the exposure means 13B, and a black electrostatic latent image is formed by the developer 22B supplied by the developer carrier 23B. The image is developed. Then, when the recording body 16 passes between the transfer means 14B and the image carrier 11B, the black electrostatic latent image is transferred to the surface of the recording body 16. Next, in the same manner as the developing unit B, the cyan image, the magenta image, and the yellow image are superimposed on the recording body 16 in which the electrostatic latent image is visualized as a black image by the developing units C, M, and Y, respectively. The color image is visualized. Next, in the recording body 16 in which the color image is visualized, the color image is fixed to the recording body 16 as a permanent image by the fixing means 30. In this way, a color image can be formed on the recording body 16.

The developing apparatus 20B includes a developing roller 1, which is excellent in developer transportability and suppresses the occurrence of toner filming, and can contribute to forming a high-density, high-quality image for a long period of time. Further, the image forming apparatus provided with the developing apparatus 20B can form a high-density and high-quality image for a long period of time.

The developing apparatus and the image forming apparatus of the present invention are not limited to those described above, and various modifications can be made as long as the object of the present invention can be achieved.

In the present invention, the image forming apparatus 10 is not limited to the electrophotographic system, and may be, for example, an electrostatic image forming apparatus. Further, the image forming apparatus 10 in which the developing roller 1 of the present invention is arranged is not limited to a tandem type color image forming apparatus in which a plurality of image carriers provided with developing units of each color are arranged in series on a transfer transfer belt. For example, a monochrome image forming apparatus provided with a single developing unit, a 4-cycle color image forming apparatus in which a developer image carried on an image carrier is sequentially subjected to primary transfer to an endless belt, or the like may be used. Further, the developer used in the image forming apparatus is a one-component non-magnetic developer, but in the present invention, it may be a one-component magnetic developer or a two-component non-magnetic developer. Alternatively, it may be a two-component magnetic developer.

The image forming apparatus is a contact type image forming apparatus in which the surface of the developing roller is arranged in contact with or in pressure contact with the surface of the image carrier. The image forming apparatus of the present invention may be a non-contact image forming apparatus.

Since the image forming apparatus 10 of the present invention includes the developing roller 1 of the present invention, the generation of fog under high temperature and high humidity conditions is suppressed, and a high quality image can be provided.

Although the present invention has been described above using the embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope of the invention described in the above embodiments. It will be apparent to those skilled in the art that improvements can be made. Further, it is clear from the description of the claims that the invention with such changes or improvements may be included in the technical scope of the present invention.

Hereinafter, the present invention will be described in detail with reference to examples. The present invention is not limited to the examples shown below.

[Example 1]
The developing roller of Example 1 was produced by the following procedure.
(Formation of primer layer)
An electroless nickel-plated shaft (made by SUM22, diameter 10 mm, length 275 mm) is washed with ethanol, and a silicone-based primer (trade name "Primer No. 16", manufactured by Shin-Etsu Chemical Co., Ltd.) is used on the surface. ) Was applied. The primer-treated shaft was fired at a temperature of 150 ° C. for 10 minutes using a gear oven, and then cooled at room temperature for 30 minutes or more to form a primer layer on the outer peripheral surface of the shaft.

(Formation of elastic layer)
An elastic body made of a rubber material was formed on the outer peripheral surface of the shaft by extrusion molding using a miraculous rubber composition formed of silicone rubber. In extrusion molding, the product is dried at 200 ° C. for 10 minutes and then cut to a predetermined length. Secondary vulcanization is performed at 225 ° C. for 4 hours to remove siloxane, and then polishing is performed to polish to a predetermined size. The surface roughness at this time was Ra = 1.2.

(Formation of coating layer)
The following compounds were mixed to prepare a composition for a coating layer.
-Acrylic polyol 35 parts by mass-Isocyanate (trade name "E402-B80B", manufactured by Asahi Kasei Co., Ltd.) 55 parts by mass-First surface roughness agent Zinc hydroxybenzoate (BONTORON E-304, manufactured by Orient Chemical Industry Co., Ltd.) 5 parts by mass, second surface roughness agent Silica particles (trade name "ACEMATT (registered trademark) OK412", manufactured by Evonik Degussa) 10 parts by mass, ion conductive agent (trade name "EF-N112", Mitsubishi Materials Electronics Chemicals Co., Ltd.) Made by Co., Ltd.)
0.5 parts by mass, fluorine-based surfactant ((meth) acrylate copolymer containing a hydroxyl group and 1% by mass or more and 10% by mass or less of fluorine atoms) 1 part by mass, thinner (trade name "EU-1F") , Dainichiseika Kogyo Co., Ltd.) 95 parts by mass

Next, the outer peripheral surface of the elastic layer was UV-treated. Then, an adhesive primer was applied onto the UV-treated elastic layer, and then the coating layer composition was applied by a spray method. The applied mixed solution was heated at 150 ° C. to 160 ° C. for 30 minutes to obtain a developing roller.
The thickness of the coating layer after drying was 11 μm.

[Example 2]
The composition for the coating layer was prepared as follows, and a developing roller was produced in the same manner as in Example 1 except that the coating layer was formed.
(Synthesis of silicone polyol)
Reactive silicone oil (trade name "KF-6000" manufactured by Shin-Etsu Chemical Co., Ltd.) 100 parts by mass, reactive silicone oil (trade name "X-22-176DX" manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by mass, isocyanate ( 15 parts by mass of trade name "D-201" (manufactured by Asahi Kasei Co., Ltd.) and 30 parts by mass of solvent butyl acetate were mixed to obtain a silicone-modified polyol after 4 hours at 100 ° C.
(Composition for coating layer)
Next, using the obtained silicone-modified polyol, a composition for a coating layer was prepared with the following composition.
-Silicone-modified polyol 100 parts by mass-Isocyanate (trade name "TPA-100", manufactured by Asahi Kasei Co., Ltd.) 14 parts by mass-First surface roughener Zirconium hydroxybenzoate (trade name "TN-105", Hodoya Chemical Co., Ltd.) (Manufactured by Kogyo Co., Ltd.) 5 parts by mass, second surface roughness agent Silicone particles (trade name "EP-2601", average particle diameter 2 μm, manufactured by Toray Dow Corning) 20 parts by mass, thinner (trade name "EU-" 1F "Dainichi Seika Kogyo Co., Ltd.) 130 parts by mass

[Example 3]
The content of the first surface roughness agent is 20 parts by mass, and the content of the second surface roughness agent is 8 parts by mass of urethane particles (trade name "P-800T", average particle diameter 6 μm, manufactured by Negami Kogyo Co., Ltd.). A developing roller was produced in the same manner as in Example 1 except that the ion conductive material was not contained.

[Example 4]
The first surface roughness agent is 5 parts by mass of iron hydroxybenzoate (trade name "BONTORON X-11, manufactured by Orient Chemical Industry Co., Ltd.), and is the same as in Example 1 except that it does not contain an ionic conductive material. A developing roller was produced.

[Example 5]
A developing roller was produced in the same manner as in Example 2 except that 0.5 parts by mass of the ionic conductive material was blended.

[Example 6]
The first surface roughness agent should be zirconium hydroxybenzoate (TN-105), the second surface roughness agent should be 8 parts by mass of urethane particles 6 μm (P-800T), and no fluorine-based surfactant should be contained. A developing roller was produced in the same manner as in Example 1 except for the above.

[Comparative Example 1]
A developing roller was produced in the same manner as in Example 1 except that the first surface roughness agent was not contained.

[Comparative Example 2]
A developing roller was produced in the same manner as in Example 1 except that it did not contain the first surface roughness agent and the fluorine-based surfactant.

[Evaluation]
The following evaluations were carried out for the above-mentioned Examples and Comparative Examples.

(Resistance value on the surface of the developing roller)
The resistance value on the surface of the developing rollers of the above Examples and Comparative Examples was measured. FIG. 4 shows a measuring device.
As shown in FIG. 4, a developing roller 1 is placed on the gold-plated plate 51, a weight 52 weighing 500 g is hung on both ends, and the resistance value between the shaft 53 and the gold-plated plate 51 is set to an ultra-high resistance at an applied voltage of 100 V. / Measured using a micro ammeter "5450" (manufactured by ADC Co., Ltd.) 54.
The developing roller is selected so that the resistance value is 9 × 10 ⁹ Ω or less by combining polyol and isocyanate, and if necessary, ionic conductive material, sodium perchlorate, lithium perchlorate, calcium perchlorate, lithium chloride. , Lithium bisimide, potassium bisimide, etc., ionic liquid pyridium type, imidazole type, quaternary ammonium type, etc. can control the ^{resistance value from 1 × 10 6 Ω to 9} × 10 9 Ω. However, basically, electron conductivity by carbon is a region where the resistance value varies depending on the dispersion conditions and is difficult to control, and an ionic conductivity mechanism is used.

(Hexadecane contact angle)
Hexadecane was set in the apparatus, droplets were dropped on a developing roller, and the hexadecane contact angle was measured using a portable contact angle meter PCA-1 (manufactured by Kyowa Interface Science Co., Ltd.).

(Charging amount Q / M)
A color image forming apparatus (trade name "C610dn2", manufactured by Oki Data Co., Ltd.) was used to mount the developing rollers of the above examples and comparative examples on a magenta color cartridge, and charged after initial printing under the conditions of a temperature of 23 ° C. and a humidity of 55%. The amount is measured by suctioning the toner formed on the surface of the developing roller with a suction-type compact charge amount measuring device, trade name: 212HS (manufactured by Trek Co., Ltd.), and measuring the charge amount Q / M (μC / g). It was evaluated according to the evaluation criteria of.
A: Charge amount is 15 μC / g or more B: Charge amount is 10 μC / g or more and less than 15 μC / g C: Charge amount is less than 10 μC / g

(Evaluation of fog under high temperature and high humidity conditions)
After mounting the developing roller on the magenta cartridge, it is left overnight at 30 ° C. and 80% RH to perform initial printing of 20 sheets, and after one white solid printing, tape is attached to a photosensitive drum and transferred onto white paper. A tape was attached to the reference paper, and the color difference ΔE between the reference value and the transferred portion was measured. Under the same conditions, the color difference Δ after printing 4000 sheets was also measured. The color difference ΔE was measured with a color difference meter (trade name “CR-241”, manufactured by Konica Minolta Co., Ltd.).
The color difference Δ after printing 4000 sheets was evaluated according to the following evaluation criteria. The fog evaluation under high temperature and high humidity conditions is A or higher.
A: ΔE is less than 1 B: ΔE is 1-2
C: 2 or more

(Filming evaluation)
Filming was evaluated by the amount of the developer adhering. Specifically, after sucking the developer adhering to the surface of the developing roller after printing 4000 sheets, the mass transferred to the filming weight measuring jig was measured. Regarding the filming evaluation, the mass of the transferred developer was evaluated according to the following evaluation criteria. The filming rating is acceptable if it is A or B.
A: 0 mg or more and 0.003 mg or less B: More than 0.003 mg and 0.006 mg or less C: More than 0.006 mg The results are shown in Table 1.

The evaluation results are shown in Table 1.

1 Develop roller 2 Axial body 3 Elastic layer 4 Coating layer 6 Transfer transfer belt 7 Second surface roughness agent 8 First surface roughness agent 10 Image forming device 11B, 11C, 11M, 11Y Image carrier 12B, 12C 12M, 12Y Charging means 13B, 13C, 13M, 13Y Exposure means 14B, 14C, 14M, 14Y Transfer means 15B, 15C, 15M, 15Y Cleaning means 16 Recorder 20B, 20C, 20M, 20Y Developer 21B, 21C, 21M, 21Y,
22B, 22C, 22M, 22Y Developer 23B, 23C, 23M, 23Y Developer carrier 24B, 24C, 24M, 24Y Developer amount adjusting means 25B, 25C, 25M, 25Y Toner supply roller 30 Fixing means 31 Fixing roller 32 Pressure roller 33 Endless belt support roller 34 Housing 35 Opening 36 Endless belt 41 Cassette 42 Support roller B, C, M, Y Development unit 51 Gold-plated plate 52 Weight 53 Shaft 54 Ultra-high resistance / micro ammeter

Claims (5)

A developing roller including a shaft body, an elastic layer provided on the outer surface of the shaft body, and a coating layer provided outside the elastic layer.
The coating layer comprises a resin having a urethane bond of polyol and isocyanate as a constituent unit, a first surface roughness agent composed of organometallic compound particles, and a second surface roughness agent composed of fine particles other than the organometallic compound particles. Including
The average particle size of the first surface roughness agent is 2 μm or less, and the average particle size of the first surface roughness agent and the average particle size of the second surface roughness agent are as follows. Development roller that meets the relationship.
Average particle size of the first surface roughness agent ≤ Average particle size of the second surface roughness agent The developing roller according to claim 1, wherein the resistance value on the surface of the developing roller is 1 × 10 ⁶ Ω or more and 9 × 10 ⁹ Ω or less. The developing roller according to claim 1 or 2, wherein the organometallic compound particles are a hydroxybenzoate metal compound. The developing roller according to any one of claims 1 to 3, wherein the hexadecane contact angle on the surface of the developing roller is 30 ° or more. An image forming apparatus including the developing roller according to any one of claims 1 to 4.

Images