JP2003028140A - Semiconductor roller and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductive roller having small unevenness in resistance of a resistance adjustment layer composed of a resin tube, and provide an electrophotographic device using the semiconductive roller. SOLUTION: As a conductive agent added to the resin tube layer formed on the surface of the roller such as a charging roller, a developing roller, a transfer roller, a discharging roller or a toner supply roller used for the electrophotographic device such as a printer, a copying machine or a facsimile machine, the conductive agent coated with a resin previously added with ions is used. Thereby, the semiconductive roller having the small unevenness in the resistance and the stable resistance is manufactured. The semiconductive roller is installed to the electrophotographic device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductive roller, which is a resin mainly used for a charging roller, a developing roller, a transfer roller, a discharging roller, a toner supply roller, etc., which are members of an electrophotographic apparatus. The present invention relates to a semiconductive roller having a resistance adjusting layer made of a tube, and an electrophotographic apparatus equipped with the semiconductive roller.

[0002]

2. Description of the Related Art Conventionally, as a semiconductive roller used in an electrophotographic apparatus such as a printer, a copying machine, and a FAX,
Examples thereof include a charging roller, a developing roller, a transfer roller, a charge eliminating roller, a toner supply roller and the like. Each roller is required to have a resistance in the semi-conductive region, but it is a fact that it is difficult to control the resistance. Generally, as a method for controlling the resistance of the semiconductive roller, a resistance adjusting layer made of a coating film or the like is provided on an elastic body serving as a base material, and ions, carbon, metal oxides, etc. are provided in the resistance adjusting layer. The method of controlling the amount of the conductive substance added is adopted.

[0003]

However, when ions are used, although a roller having a small variation in resistance can be obtained, it is possible to cover only a relatively high resistance region and the resistance is easily influenced by the environment. There was a problem. In addition, there are problems that the resistance is likely to change due to energization, and that ions easily bleed and become a pollution source. On the other hand, when a conductive material such as carbon or metal oxide is used, the resistance is not easily influenced by the environment,
Although there are many advantages such as a small change in resistance due to energization, a pollution problem is less likely to occur, and a required resistance area can be covered, there are large variations in resistance,
It has problems such as a large voltage dependence of resistance. Therefore, in order to improve the reproducibility and stability of resistance, some attempts have been made to add a dispersant together with the above-mentioned conductive substance, but the above-mentioned additive itself causes a new problem that it easily becomes a pollution source. There is. Further, the resistance adjusting layer may be formed by coating with a paint, forming by powder coating, forming by a resin tube formed by extrusion or the like. Here, in the case of aiming at cost reduction, the method of forming with a resin tube is the most advantageous, but from the viewpoint of resistance control described above, it is a more disadvantageous forming method.

The present invention has been made in view of the conventional problems, and provides a semi-conductive roller having a small resistance variation of a resistance adjusting layer made of a resin tube, and an electrophotographic apparatus using the semi-conductive roller. The purpose is to provide.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that carbon, metal powder coated with a resin to which ions have been added in advance as a conductive agent to be added to a resistance adjusting layer formed of a resin tube, It has been found that a semiconductive roller having a small variation in resistance can be stably obtained by using a conductive agent such as a metal oxide, and the present invention has been completed. That is, the semiconductive roller according to claim 1 is characterized in that, as the conductive agent added to the resin tube formed on the roller surface, a conductive agent coated with a resin to which ions are added in advance is used. is there. The semiconductive roller according to claim 2, wherein the coating amount of the resin is 0.01 to the conductive agent.
It is set to 50 wt%. In the semiconductive roller according to the third aspect, the conductive agent is at least one of carbon, metal powder, metal oxide, or a mixture thereof. According to a fourth aspect of the present invention, in the semiconductive roller coated with the resin, the solvent insolubility rate of the resin component represented by the following relational expression is 50% or more. Here, the solvent insolubility rate (%) = (B / A) × 100, where A: the weight of the resin component in the resin-coated conductive agent before being immersed in the solvent B; the resin-coated conductive agent in a good solvent, 25
Weight of resin component after immersion at 24 ° C. for 24 hours In the semiconductive roller according to claim 5, the surface roughness of the roller is 4 μm or less. According to a sixth aspect of the present invention, in the semiconductive roller, an elastic layer is provided inside the resin tube. The semiconductive roller according to claim 7,
The elastic layer is made of any one of urethane rubber, silicone rubber, ethylene propylene rubber, epichlorohydrin rubber, or a material obtained by mixing two or more kinds thereof. An electrophotographic apparatus according to claim 8 is characterized in that the semiconductive roller according to any one of claims 1 to 7 is mounted.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. 1 (a) and 1 (b) are diagrams showing a configuration example of a semiconductive roller according to the present invention. The semiconductive roller 10 has an elastic layer 12 formed on the outer circumference of a shaft 11 made of metal or plastic. Further, a resin tube layer 13 which is a resistance adjusting layer is further provided on the surface of the elastic body layer 12.
In the present invention, the resin tube layer 13 is a resin tube layer to which a conductive agent coated with resin in advance is added. That is, by using a conductive agent coated with resin in advance as the conductive agent added to the resin forming the resin tube layer 13, the conductive agent such as normal carbon or metal oxide, which is the uncoated conductive agent, is used as it is. Compared with the case of adding, the dispersibility of the conductive agent can be controlled more easily, and variations in resistance and voltage dependence of resistance can be reduced. At this time, the coating amount of the resin is 0.01 to 50 wt%, preferably 0.
01-30 wt%, more preferably 0.01-20 wt%
% Is appropriate. When the coating amount is less than the above range, sufficient effect of improving the dispersibility cannot be obtained, and when it is more than the above range, sufficient conductivity cannot be obtained as described later. By the way, if the resin is simply coated, naturally, the original conductivity of the conductive agent is impaired, and although the dispersibility can be controlled, the conductivity of the elastic body to which the conductive agent is added is difficult to be expressed. Therefore, in the present invention, the following contradictory problems of dispersibility and conductivity are solved by selecting the following resins as the coating resin. That is, ions are added to the resin coating the conductive agent, the dispersibility is mainly controlled by the coating resin, and the conductivity is compensated by the ions.

The resin to be coated may be any resin type as long as the ions described later are dissolved or dispersed therein. Examples thereof include urethane resin, acrylic resin, polyester resin, urethane-modified acrylic resin, silicone resin, nylon resin, epoxy resin, styrene resin, butyral resin, vinylidene chloride resin, melamine resin, phenol resin and fluororesin. These resins may be used alone,
Two or more kinds may be used in combination, and particularly, urethane resin, fluororesin, silicone resin, acrylic urethane resin are preferable, and at least one kind of resin which is the same as the material constituting the elastic layer described later is used. It is preferable to include.

The ions added to the resin to be coated include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (eg lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (eg stearyltrimethylammonium), benzine. Perchlorates such as trimethylammonium, modified fatty acid dimethylethylammonium, chlorates, hydrochlorides, bromates, iodates, borofluorides, sulfates, ethylsulfates, carboxylates, sulfonates Ammonium salts such as, perchlorates, chlorates, hydrochlorides, bromates, iodates of alkali metals and alkaline earth metals such as lithium, sodium, potassium, calcium and magnesium Fluoroboric acid salts, trifluoromethyl sulfate, and sulfonic acid salts. These ions may be used alone or in combination of two or more, and the addition amount thereof is not particularly limited,
The amount is usually 0.01 to 30 parts by weight, preferably 0.01 to 15 parts by weight, based on 100 parts by weight of the resin.

The conductive agent to be coated is a so-called conductive substance, and examples thereof include carbon, metal and metal oxide. For example, conductive carbon such as Ketjen black and acetylene black, SAF, ISAF, H
Carbon for rubber such as AF, FEF, GPF, SRF, FT, MT, carbon for ink subjected to oxidation treatment, pyrolytic carbon, natural graphite, or antimony-doped tin oxide, titanium oxide, zinc oxide, nickel, copper ，
Examples thereof include metals such as silver and germanium and metal oxides.

As a method for coating the above resin, for example, dispa coat, coat mizer, etc. may be mentioned. The disperse coat is provided with a powder supply section provided at the upper part and a multistage disperser capable of supplying liquid in multiple stages from the lateral direction. The above-mentioned powder supply is controlled by controlling the operating conditions of the multistage disperser. Liquid components including coating resin on the surface of the conductive powder supplied from the
The operation of wetting the surface of the conductive powder with a liquid can be carried out in a very short time. The coatmizer supplies the conductive powder to be coated into a jet jet to form a dispersion layer, and then forms a mist-like stream made of fine particles of a droplet containing a coating resin in a position parallel to this. Then, the surface of the conductive powder is coated with a resin by colliding with the conductive powder to be coated.

With respect to the conductive agent coated with the resin, it is preferable that the solvent insolubility rate of the resin component shown by the following relational expression is 50% or more, particularly 70% or more. Solvent insolubility rate (%) = (B / A) × 100 where A: weight of resin component in resin-coated conductive agent before solvent immersion B; resin-coated conductive agent in a good solvent, 25
Weight of resin component after soaking at 24 ° C. for 24 hours When the solvent insolubility ratio is less than 50%, the semiconductive roller of the present invention is mounted on an electrophotographic apparatus such as a printer, a copying machine, or a fax machine, and a developing roller. , Transfer roller,
When used as a semi-conductive roller such as a static elimination roller,
Contamination occurs on the contact portion of the photoconductor such as OPC and causes a problem on the image. As the solvent for measuring the solvent insolubility, methyl ethyl ketone or the like is used for the fluororesin, methanol or the like is used for the polyamide resin, methyl ethyl ketone or toluene is used for the acrylic urethane resin, and melamine resin is used. It is preferable to use acetone, isopanol or the like, and toluene or the like for the silicone resin.

The resin material forming the resin tube layer 13 to which the conductive agent coated with the resin to which the ions have been added is added may be any material. For example, polyamide, polyimide, polycarbonate, polyarylate, Polyacetal, polypropylene, polyethylene, polyphenylene ether, polysulfone,
Polyethylene terephthalate, polyether sulfone, polyetherimide, polybutadiene, polyisobutylene, polyvinyl fluoride, polyvinylidene fluoride, acrylic, alkyl acrylate copolymer, ethylene tetrafluoroethylene copolymer, hexafluoropropylene, perfluoroalkyl vinyl ether One or more of copolymers, polyester ester copolymers, polyester ether copolymers and polyurethane copolymers can be mixed, and particularly, polyamide, polycarbonate, acrylonitrile copolymer and polyvinylidene fluoride are preferable. Is. In addition, if necessary, in addition to the above-mentioned components, for example, various fillers, coupling agents, antioxidants, lubricants, in a range that does not impair the effects of the present invention,
Functional components such as a surface treatment agent, a pigment, an ultraviolet absorber, a foaming agent, a cross-linking agent, and a compatibilizer may be appropriately mixed. The resistance of this resin layer is appropriately selected, but it is 10 ⁶ to 10 ¹³ Ω.
It is preferable to adjust to a semiconductive region of -cm, especially 10 ⁷ to 10 ¹² Ωcm. In the semi-conductive region where variations in resistance tend to occur, the variations in resistance can be effectively reduced by adding the conductive agent of the present invention coated with resin in advance. The resin tube layer may be a single layer or a plurality of layers, and the thickness is appropriately selected, but usually 5 to 1000 μm.
A range of m is used. The resin tube layer is formed from a molten resin by an extrusion method, but the method is not limited to this. Although the resistance of this resin tube layer is appropriately selected, it is 10 ⁴ to 10 ¹⁴ Ω · c.
It is preferable to adjust to a semiconductive region of m, particularly 10 ⁴ to 10 ⁹ Ω · cm. In the semi-conductive region where variations in resistance tend to occur, the variations in resistance can be effectively reduced by adding the conductive agent of the present invention coated with resin in advance.

The elastic body constituting the elastic body layer provided inside the resin tube layer is not particularly limited as long as it has an elastic function, but examples thereof include urethane rubber, silicone rubber and nitrile. Rubber, ethylene propylene rubber, ethylene propylene diene rubber, styrene butadiene rubber, butadiene rubber, isoprene rubber,
Natural rubber, acrylic rubber, chloroprene rubber, butyl rubber, epichlorohydrin rubber and the like can be mentioned. These may be used alone or in combination of two or more, but urethane rubber, silicone rubber and ethylene propylene rubber are particularly preferable. In addition,
If necessary, a filler such as silica or calcium carbonate, a plasticizer, a crosslinking accelerator, a crosslinking retarder, an antiaging agent, a colorant and the like may be appropriately mixed. The elastic body may be a foam, and in this case, the density is 0.05 to 0.9.
g / cm ³ is suitable. The elastic layer is formed by placing the resin tube on the inner surface of a predetermined molding and injecting the elastic material into it, or by using the resin tube as a mold and injecting the elastic material into it. However, the method is not limited thereto. Moreover, you may form a coating film on the outer surface of the said resin tube layer as needed.

Further, the object of the present invention is to reduce the variation in resistance, and therefore it is desirable that the shape is uniform, and the surface roughness of the roller surface is a ten-point average roughness. It is preferable that Rz is 4 μm or less. The semiconductive roller of the present invention is suitable for use in, for example, a charging roller, a developing roller, a transfer roller, a charge eliminating roller, a toner supply roller and the like used in an electrophotographic apparatus such as a printer, a copying machine and a FAX. Specifically, as shown in FIG. 2, the photosensitive drum (OP
The charging roller 10 which is the semi-conductive roller of the present invention is rotated while being brought into contact with the C drum) 20, and a DC voltage or a DC voltage is applied between the photosensitive drum 20 and the charging roller 10 by the voltage applying means 30. An example is a charging device of a printer configured to apply a voltage obtained by superimposing an AC voltage on a DC voltage to charge the photosensitive drum 20. The semiconductive roller of the present invention has a small variation in resistance and has stable resistance, and
Since the problem of contamination is unlikely to occur, by mounting this semi-conductive roller, it is possible to stably supply an electrophotographic apparatus capable of obtaining a good image.

<Example> The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following. [Example 1] Nylon 12 (manufactured by Daicel: Daiamide L)
1940), 25 phr of the following resin coating CB type A was added, and the mixture was kneaded with a twin-screw kneader to pelletize it, and then an extruder was used to prepare a conductive resin tube having an outer diameter of 12 mmφ and a thickness of 300 μm. did. next,
After placing the above resin tube and 6 mmφ shaft in the mold, cast conductive urethane foam to obtain an outer diameter of 12
A charging roller of mmφ was manufactured. Resin coating CB
Type A is Denka black carbon (manufactured by Denki Kagaku Kogyo), and acrylic urethane resin EAU65B (manufactured by Asia Industrial Co., Ltd.) / Ion:
Quaternary ammonium perchlorate KS555 (made by Kao) / I
The PDI-based cross-linking agent Excel Hardener HX (manufactured by Asia Industry) was selected. The ratio of EAU65B, KS555 and Excel hardener HX was adjusted and used so that the solid content weight ratio was 6: 0.48: 4. The coating method was to use a spiral flow device (made by Freund) to make M
A solution obtained by mixing the acrylic urethane resin and the cross-linking agent in an EK solvent is blown in as a mist to coat the resin on the surface of DENKA black carbon and heat it.
Denka black carbon particles coated with resin in advance were prepared.

Example 2 In place of the resin coating CB type A used in the above example 1, the resin to be pre-coated in the above resin coating CB type A was replaced by
Urethane resin DP307 (manufactured by Sanyo Chemical) / ion: quaternary ammonium perchlorate KS555 (manufactured by Kao) / IPD
A charging roller was prepared in the same manner as in Example 1 except that a resin coating CB type B which was an I-type cross-linking agent Excel Hardener HX (manufactured by Asia Kogyo Co., Ltd.) was used. The ratio of DP307, KS555, and Excel hardener HX was adjusted and used so that the solid content weight ratio was 4.5: 0.36: 1.

[Reference Example 1] Instead of the resin coating CB type A used in the above-mentioned Example 1, the resin to be pre-coated in the above resin coating CB type B was replaced by
Acrylic urethane resin EAU65B (made by Asia Industry) /
Ion: Resin coating CB type C using only perchlorate of quaternary ammonium KS555 (manufactured by Kao)
A charging roller was produced in the same manner as in Example 1 except the above.

[Comparative Example 1] Resin coating C was used in place of resin coating CB type A used in Example 1 above.
A charging roller was produced in the same manner as in Example 1 except that resin coating CB type D obtained by removing ions from the resin component to be coated in B type A was used. [Comparative Example 2] A charging roller was produced in the same manner as in Example 1 except that Denka black carbon was used as it was in the above Example 1 without resin coating.

The characteristics of the charging rollers of the examples, reference examples and comparative examples thus manufactured were measured, and the charging roller was mounted on a printer to perform an image output test and a contamination test. The results are shown in the table of FIG. The characteristics were measured and the test results were measured according to the following criteria. (1) Amount of resin coated TGA of resin coated in advance
Using the apparatus, the temperature rising rate is 20 ° C./min. The temperature was raised to 800 ° C. and the amount of coated resin was calculated from the change in weight. (2) Solvent Insolubility The carbon previously resin-coated was immersed in a MEK solution at 25 ° C. for 24 hours, dried at 100 ° C. for 5 hours, and the weight after drying was measured. The solvent insolubility rate was calculated according to the following formula from the amount of resin before immersion from TGA and the weight change before and after immersion. Solvent insolubility rate (%) = (B / A) × 100 Here, A represents the weight of the resin component in the resin-coated conductive agent before the solvent immersion, and B represents the resin-coated conductive agent in a good solvent, 25 The weight of the resin component after soaking at 24 ° C. for 24 hours is shown. (3) Roller surface roughness A surface roughness measuring device (Surfcom 120A, manufactured by Tokyo Seimitsu Co., Ltd.) was used to measure the surface of the charging roller thus prepared, and a ten-point average roughness Rz
Was measured. (4) Roller resistance and variation in resistance The charging roller and the metal drum thus manufactured were pressed against each other with a load of 500 g and rotated, and then 500 V was applied between the roller and the metal drum to measure the resistance of the roller. The roller resistance was an average value, and the variation of the roller resistance was the difference between the maximum resistance and the minimum resistance within one rotation of the roller. (5) Image Display Test and Contamination Test The charging roller thus prepared was mounted on a commercially available LBP, an image was displayed (halftone image), and the image state was visually judged. In addition, the charging roller and the OPC drum thus manufactured were combined with each other.
Pressed with a load of 00 kg, 1 at 40 ° C, 85% RH environment
After left for 0 days, the OPC drum was mounted on the printer device, and 10 images were printed. The contamination state was judged based on the degree of image defects when printing 10 sheets. At this time,
The case where a line-shaped defect occurred at the image position corresponding to the above-mentioned pressed portion was judged as NG.

As is clear from the characteristic measurement results and the test results shown in FIG. 3, the charging rollers of Examples 1 and 2 of the present invention have a small variation in resistance and a stable resistance. Even when mounted, a good image could be obtained and no pollution problem occurred. On the other hand, in Comparative Example 1 in which ions were removed from the coating resin component of Example 1, the conductivity was not compensated, so that not only the roller resistance value increased but also the resistance variation became large, and it was mounted on the printer. Even when it was done, the uniformity of the image could not be obtained. Further, in Comparative Example 2 in which carbon was used as it was, although the roller resistance value could be adjusted,
Not only was the dispersibility poor and the roller surface roughness increased, but the resistance variation also increased, and even when it was mounted on a printer, mottled patterns occurred. On the other hand, in Reference Example 1 in which the cross-linking agent of Example 1 was omitted, not only a slight mottled pattern was generated on the image, but also a pollution problem occurred.
Became.

[0021]

As described above, according to the present invention,
As a conductive agent added to the resin tube layer formed on the roller surface, a conductive agent coated with a resin to which ions have been added in advance is used, so that there is little variation in resistance and a semi-conductive roller having stable resistance is obtained. be able to. Further, by using the semiconductive roller as a charging roller, a developing roller, a transfer roller, a charge eliminating roller, a toner supply roller, etc. used in an electrophotographic apparatus such as a printer, a copying machine, and a FAX, a good image can be stabilized. It is possible to provide an electrophotographic apparatus that can be obtained as a result.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a semiconductive roller according to the present invention.

FIG. 2 is a diagram schematically showing a charging device of a printer according to the present invention.

FIG. 3 is a view showing a result of trial production of a semiconductive roller according to the present invention.

[Explanation of symbols]

10 charging roller, 11 shaft, 12 elastic layer,
13 semi-conductive resin tube layer, 20 photosensitive drum, 3
0 voltage applying means.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/16 103 G03G 15/16 103 21/06 21/00 340 (72) Inventor Hajime Kitano Ogawa Higashimachi, Kodaira-shi, Tokyo 3-5-5 F Term (Reference) 2H035 AA15 2H071 BA43 DA06 DA07 DA08 DA09 2H077 AA15 AC04 AD06 FA13 FA16 FA22 2H200 FA18 HA02 HA28 HB12 HB43 HB45 HB46 HB47 MA03 MA12 MA14 MA17 MA20 MC20 A14 A14 A02 BA14 A20 A14 A14 GA02 GA57 GA58 GA60 HA03 HA04 HA20 HA42 HA43 HA46 HA47 HA48 HA53

Claims (8)

[Claims] 1. A semiconductive roller having a resistance adjusting layer made of a resin tube having a conductive agent added to the surface thereof, wherein the conductive agent is coated with a resin to which ions have been added in advance. 2. The semiconductive roller according to claim 1, wherein the coating amount of the resin is 0.01 to 50 wt% with respect to the conductive agent. 3. The semiconductive roller according to claim 1, wherein the conductive agent is at least one of carbon, metal powder, metal oxide, or a mixture thereof. 4. The conductive agent coated with the resin according to any one of claims 1 to 3, wherein the solvent insolubility of the resin component represented by the following relational expression is 50% or more. The semiconductive roller described. Solvent insolubility rate (%) = (B / A) × 100 where A: weight of resin component in resin-coated conductive agent before solvent immersion B; resin-coated conductive agent in a good solvent, 25
Weight of resin component after immersion for 24 hours at ℃ 5. The semiconductive roller according to claim 1, wherein the surface roughness of the roller is 4 μm or less. 6. The semiconductive roller according to claim 1, further comprising an elastic layer inside the resin tube. 7. The elastic layer is made of any one of urethane rubber, silicone rubber, ethylene propylene rubber, epichlorohydrin rubber, or a material obtained by mixing two or more kinds of them. The semiconductive roller according to claim 6. 8. An electrophotographic apparatus equipped with the semiconductive roller according to any one of claims 1 to 7.