JP2003262998A - Conductive roller and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of a conductive roller by lightening its weight and simplifying its manufacture process. <P>SOLUTION: The conductive roller is characterized in that it has a shrink tube layer 2 formed by coating the outer circumference of a conductive resin shaft 1 with a conductive shrink tube. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer roller, a developing roller, a toner supply roller, a charging roller, a cleaning roller and the like used in an electrophotographic type or electrostatic recording type image forming apparatus such as a copying machine, a facsimile and a printer. The present invention relates to a conductive roller that is preferably used as.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus such as a copying machine, a printer or a copying machine, as a transfer member, a toner supplying member, a charging member and a cleaning member,
A medium resistance elastic roller is used.

Conventionally, these transfer roller, developing roller,
As a conductive roller used as a toner supply roller, a charging roller, or a cleaning roller, a conductive rubber, a polymer elastomer, or a polymer in which a conductive agent is added to the outer periphery of a metal conductive shaft to impart conductivity What is used is one in which a conductive elastic layer made of foam is formed, and a coating film such as a surface roughness adjusting layer or a surface layer is further formed on the outer periphery of the conductive elastic layer depending on the application.

[0004]

However, the conventional conductive roller is heavy due to the use of the metal shaft, and in particular, in the case of a large diameter roller, the weight is considerable, so that a peripheral device such as a drive system is required. There is a drawback that it becomes large. Further, a complicated vulcanization molding step by extrusion molding or injection molding is required to form the elastic layer, and a coating step and a drying step for forming a coating film such as a surface roughness adjusting layer or a surface layer. A plurality of complicated steps are required, and these are one of the causes of the high cost.

The present invention has been made in view of the above circumstances, and is a conductive material which is suitably used as a transfer roller, a developing roller, a toner supply roller, a charging roller, a cleaning roller, etc. in an image forming apparatus such as a printer or a copying machine. The purpose of the present invention is to reduce the weight of the roller and to simplify the manufacturing process thereof to reduce the cost.

[0006]

MEANS FOR SOLVING THE PROBLEMS AND BEST MODE FOR CARRYING OUT THE INVENTION To achieve the above object, the present inventor has realized a shrink tube layer formed by coating the outer periphery of a conductive resin shaft with a conductive shrink tube. A conductive roller is provided.

That is, according to the present invention, the shaft of the conductive roller is formed of a conductive resin to reduce the weight of the roller, and the elastic layer which is conventionally formed of rubber, elastomer, polymer foam or the like, In place of all or part of the coating layer formed of various resin coatings, by forming these functional layers with a conductive shrink tube, by covering the shrink tube with the shaft and causing thermal shrinkage, It is possible to easily form a functional layer that replaces the elastic layer or the coating layer, simplify the forming process of these functional layers, and effectively reduce the manufacturing cost.

The present invention will be described in more detail below.
As shown in FIGS. 1 (A) and 1 (B), the conductive roller of the present invention is one in which the outer circumference of a shaft 1 made of a conductive resin is covered with a shrink tube 2.

The shaft 1 is a shaft made of a resin having conductivity, and the material for forming the shaft 1 is a conductive resin composition in which a conductive agent is mixed with a synthetic resin to impart conductivity, and this conductive resin composition is used. The shaft 1 is formed by molding an article by an appropriate method such as extrusion molding or injection molding.

The synthetic resin constituting the conductive resin composition is not particularly limited, but may be appropriately selected from general-purpose resins and engineering plastics. More specifically, engineering plastics include, for example, polyacetal, polyamide resin (polyamide 6, polyamide 6.6, polyamide 12, polyamide 4.6, polyamide 6/10, polyamide 6.1).
2, polyamide 11, polyamide MXD6), polybutylene terephthalate, polyphenylene ether, polyphenylene sulfide, polyether sulfone, polycarbonate, polyimide, polyamide imide, polyether imide, polysulfone, polyether ether ketone, polyethylene terephthalate, polyarylate, liquid crystal polymer or Examples include polytetrafluoroethylene. Also, as general-purpose resin, polypropylene,
Examples thereof include ABS (acrylonitrile-butadiene-styrene) resin, polystyrene, and polyethylene. In addition, melamine resin, phenol resin, silicone resin and the like can be mentioned. These may be used alone or in combination of two or more. Among these, the engineering plastics are preferable, and further, polyacetal, polyamide resin, polybutylene terephthalate, polyphenylene ether, polyphenylene sulphite, polycarbonate and the like are preferable from the viewpoint of excellent plasticity and moldability, and excellent mechanical strength. . In particular, a mixed resin of polyamide 6.6 and polyamide MXD6 (a polyamide obtained from metaxylenediamine and adipic acid) is suitable.

Various kinds of conductive agents can be used as the conductive agent to be added to the conductive resin composition, as long as they can be uniformly dispersed in the resin composition. Carbon black powder, graphite powder Powdery conductive agents such as carbon fiber, metal powders such as aluminum, copper and nickel, metal oxide powders such as oxides, titanium oxides and zinc oxides, and conductive glass powders are preferably used. These may be used alone or in combination of two or more. The blending amount of this conductive agent may be appropriately selected according to the intended use and situation of the conductive roller,
Although not particularly limited, it is usually preferably 5 to 40% by weight, particularly preferably 5 to 20% by weight, based on the entire composition.

If desired, various conductive or non-conductive fibrous substances, whiskers, or ferrite may be added to the conductive resin composition for the purpose of reinforcement or increase. Here, examples of the fibrous material or whiskers include fibers such as carbon fibers and glass fibers, and inorganic whiskers such as potassium titanate. These may be used alone or in combination of two or more. The amount of these fibrous substances, whiskers or ferrite mixed varies depending on the length and diameter of the fibrous substances or whiskers used, the type of synthetic resin, or the like, and may be appropriately selected depending on the situation. It is preferably 5 to 70% by weight, particularly preferably 10 to 20% by weight.

Here, the shaft 1 constituting the conductive roller of the present invention may be a solid body or a hollow body, but from the viewpoint of weight reduction, it is preferably a hollow body. The method for producing the shaft 1 using the conductive resin composition is not particularly limited, and the conductive resin composition may be molded by a known molding method according to the type of synthetic resin, Generally, an injection molding method using a mold is preferably used. Especially when a hollow body is used,
Using a molding die having a mold body having a cylindrical hollow portion, the molten conductive resin composition is injected and injected into the cylindrical hollow portion, and an inert gas is introduced into the cylindrical hollow portion. A method in which a hollow portion is formed in the conductive resin composition by introducing the gas and using the pressure of this gas is preferably used.

The shaft 1 is not particularly limited, but has a volume resistivity of 1 × 10 ⁰ to 25 ° C.
1 × 10 ¹² Ω · cm, especially 1 × 10 ² to 1 × 10 ³ Ω · c
It is preferably m. Also, this shaft 1 is J
Bending strength measured according to IS K7171 is 80M
It is preferably Pa or more, and the bending strength is 80M.
If it is less than Pa, the mechanical strength is low and it is difficult to use it as the shaft of a conductive roller. A more preferable range of this bending strength is 100 MPa or more, and particularly 150 MPa or more is preferable. Although the upper limit of the bending strength is not particularly limited, it is generally 500 MPa or less.

The diameter (outer diameter) of the shaft 1 is usually 4 to 60 m although it depends on the use of the conductive roller.
m, especially about 6 to 20 mm. Especially 12m in diameter
When the diameter is larger than m, the effect of weight reduction of the present invention is remarkable.

Next, the shrink tube forming the shrink tube layer 2 formed on the outer periphery of the shaft 1 is appropriately selected according to the application of the conductive roller, required characteristics, performance, etc., and shrinks by heat treatment or the like. However, any material can be used as long as it can be brought into close contact with the outer circumference of the shaft 1. Specifically, a shrink tube made of soft polyolefin, silicone rubber, ethylene propylene rubber, polyvinyl chloride, polystyrene, polyester or fluororesin is preferably used.

The shrink tube layer 2 is not particularly limited, but has a volume resistivity of 1 × 10 ² -1.
It is preferably × 10 ¹⁰ Ω · cm, and more preferable resistance value is 1 × 10 ⁴ to 1 × 10 ⁸ Ω · cm. It should be noted that this resistance value can be achieved by incorporating an appropriate conductive agent into the resin material or rubber material forming the shrink tube.

The thickness of the shrink tube layer 2 is appropriately set according to the application of the conductive roller and the required performance, and is not particularly limited, but is usually 0.1 to 10 mm, particularly It is preferably 0.5 to 5 mm.

The shrink tube layer 2 is formed by covering the shaft 1 with the shrink tube, shrinking the shrink tube by heat treatment or the like, and bringing the shrink tube into close contact with the outer periphery of the shaft 1. In this case, although not particularly limited, a hot melt adhesive layer (not shown) is formed between the shrink tube layer 2 and the shaft 1 to improve the adhesion between the shrink tube and the shaft 1. It is also possible to heat and melt the hot melt adhesive when the shrink tube is heat-shrinked, so that the shaft 1 and the shrink tube layer 2 can be more firmly and reliably bonded. The hot-melt adhesive layer may be formed by applying a liquid hot-melt material or by arranging a sheet-shaped or film-shaped hot-melt material.

The conductive roller of the present invention is the shaft 1 described above.
The shrink tube layer 2 is formed on the outer periphery of the, but depending on the application, required performance, and characteristics, as shown in FIG.
As shown in (B), an intermediate layer 3 is provided between the shaft 1 and the shrink tube layer 2 and is made of a coating film formed of a coating material in which a cross-linking agent and a conductive agent are added to an organic solvent resin or an aqueous resin. be able to.

Examples of the resin forming the intermediate layer 3 include urethane-modified acrylic resin, polyurethane resin, acrylic resin, polyamide resin, fluororesin, alkyd melamine resin, etc. as the organic solvent-based resin, and water-based resin. Examples are polyvinyl acetal resin, vinylidene chloride resin, urethane resin, acrylic resin, polyester resin and the like.

The cross-linking agent is appropriately selected according to the type of resin used, and for example, oxazoline-based, epoxy-based,
A melamine-based, guanamine-based, isocyanate-based, phenol-based, or other crosslinking agent is preferably used. Further, the conductive agent is not particularly limited, and a known electronically conductive substance or ionic conductive substance is preferably used. The electric resistance of the intermediate layer adjusted by adding a conductive agent is not particularly limited, but is usually 10 ¹ to 10 ¹² Ω · cm, particularly 10 ⁴ to 1
It is preferable that the 0 ⁸ Ω · cm.

The intermediate layer 3 is formed by applying a coating material containing the above organic solvent-based or water-based resin, a cross-linking agent, and a conductive agent by a dipping method, a spray method, a roller coater method or the like, and its thickness is Although not particularly limited, it is usually 1 to 500 μm, particularly 3 to 300 μm.
It is preferable that

Further, depending on the application, as shown by the alternate long and short dash line in FIGS. 1 (A) and 1 (B), the outer periphery of the shrink tube layer 2 is for the purpose of improving smoothness, low friction, and toner adhesion. Alternatively, the conductive, semi-conductive or insulating surface layer 4 can be formed.

The surface layer 4 is not particularly limited, but may be one kind or a mixture of two or more kinds selected from urethane modified acrylic resin, polyurethane resin, acrylic resin, polyamide resin, fluororesin, alkyd melamine resin and the like. It can be formed of a resin, and can be formed by applying a coating material of these resins by a dipping method, a spray method, a roll coater method or the like.

Similar to the case of the intermediate layer 3, the surface layer 4 may be blended with an appropriate crosslinking agent or conductive agent,
The resistance value is 10 ¹ to 10 ¹² Ω · cm, especially 10 ⁸ to 10
It is preferably about ¹² Ω · cm. As the cross-linking agent and the conductive agent, the same ones as those exemplified for the above-mentioned intermediate layer 3 can be exemplified. The surface layer 4 preferably has a thickness of 1 to 50 μm and 1 to 40 μm.

Regarding the use of the conductive roller of the present invention,
Although not particularly limited, a transfer roller, a developing roller, an electrophotographic image forming apparatus such as a copying machine or a printer,
It can be suitably used as a toner supply roller, a charging roller, a cleaning roller, or the like.

[0028]

As described above, the conductive roller of the present invention can be reduced in weight by using a resin shaft instead of the conventional metal shaft, and can use a shrink tube. By forming the functional layer by using the above method, it is possible to inexpensively manufacture without requiring a complicated layering process.

[0029]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. Example 1 A conductive resin composition having the following composition was injection-molded to form a hollow cylinder (outer diameter 16 mm, wall thickness 2 mm, length 25).
A conductive resin shaft of 0 mm) was obtained. The electric resistance of this shaft was 1 × 10 ² Ω · cm (25 ° C.), and the bending strength according to JIS K7171 was 170 MPa. Conductive resin composition Polyamide 6.6 30% by weight Polyamide 6 30% by weight Carbon black 20% by weight Inorganic whiskers (Wollastonite) 20% by weight

A conductive shrink tube (1 × 10 ⁸ Ω · c) made of ethylene-propylene rubber having a thickness of 5 μm is formed by laminating a polyolefin-based melt adhesive on the outer peripheral surface of the obtained shaft.
m), and heat-shrink this by heating in an oven to form a shrink tube layer having a thickness of 1 mm,
A conductive roller was obtained.

Example 2 A shaft similar to that of the above Example 1 was prepared, and this was dipped in a coating material prepared by adding 3 parts by weight of an ion conductive agent to 100 parts by weight of a polyurethane emulsion, and a thickness of 250 μm was formed on the outer peripheral surface of the shaft. , Volume resistivity 1
After forming a shrink tube similar to that of Example 1 on a shaft having an intermediate layer of × 10 ⁶ Ω · cm and having an intermediate layer formed on the outer peripheral surface of the shaft, the shrink tube is formed, and then a fluororesin ( EFVE alternating polymer) was dipped in a paint dissolved in a solvent of methyl ethyl ketone, and a surface layer having a thickness of 10 μm and a volume resistivity of 1 × 10 ¹² Ω · cm was formed on the outer peripheral surface of the shrink tube layer to obtain a conductive roller. .

When the conductive roller of each of Examples 1 and 2 was mounted on a laser beam printer as a developing roller and an image was formed, a good image was obtained regardless of which conductive roller was used.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a conductive roller according to the present invention.

[Explanation of symbols]

1 shaft 2 Shrink tube layer 3 Middle class 4 surface layer

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/02 101 G03G 15/02 101 4J002 15/08 501 501/08 501A 501D 15/16 103 15/16 103 103 / 10 21/00 312 F Term (Reference) 2H071 BA03 BA43 DA06 DA08 DA09 DA13 2H077 AC04 AD06 FA13 FA25 2H134 GA01 GB02 HA03 KG03 KG07 KG08 KH10 2H200 FA13 GA23 GA44 GB15 HA01 HA28 HB12 HB22 HB45 HB46 MA26 MA27 JA03 JA03 MA25 JA25 MA20 MB01 MB04 MC04 3J103 AA02 AA14 AA15 AA23 AA51 BA41 FA19 GA02 GA57 GA58 GA60 HA03 HA06 HA12 HA20 HA41 HA53 4J002 BB021 BB111 BC021 BD151 BN151 CB001 CC031 CC181 CF1 DA0360C1 DA036CH1 CH1C1 DA036CH1 CH1C1 DA036CH1 CH1C1 DA016CH1 CH1C1 DA016CH1 CH1C1 DA016CH1 CH1C1DA036 DE096 DE106 DE117 DE136 DE187 DL006 DL007 FA046 FA047 FA067 FD116 GF00 GM00 GQ02

Claims (9)

[Claims] 1. A conductive roller having a shrink tube layer formed by coating a conductive shrink tube on the outer periphery of a conductive resin shaft. 2. The conductive roller according to claim 1, further comprising an intermediate layer between the shaft and the shrink tube layer. 3. The electrically conductive roller according to claim 1, wherein the electrically conductive resin shaft is a resin solid body or hollow body having a volume resistivity of 1 × 10 ⁰ to 1 × 10 ¹² Ω · cm at 25 ° C. . 4. The conductive resin shaft is JIS K
The conductive roller according to any one of claims 1 to 3, which has a bending strength of 80 MPa or more measured according to 7171. 5. The conductive resin shaft is made of polyacetal, polyamide 6, polyamide 6 · 6, polyamide 1
2, polyamide 4.6, polyamide 6/10, polyamide 6/12, polyamide 11, polyamide MXD6, polybutylene terephthalate, polyphenylene ether,
Polyphenylene sulfide, polyether sulfone,
Conductivity obtained by blending one or more synthetic resins selected from polycarbonate, polyimide, polyamideimide, polyetherimide, polysulfone, polyetheretherketone, polyethylene terephthalate, polyarylate, liquid crystal polymer and polytetrafluoroethylene with a conductive agent. It is formed of a water-soluble resin composition.
4. The conductive roller according to any one of 4 above. 6. The conductive roller according to claim 5, wherein the conductive resin composition forming the conductive resin shaft contains one kind or two or more kinds of a fibrous material, whiskers and ferrite. 7. The shrink tube is made of soft polyolefin, silicone rubber, ethylene propylene rubber,
The conductive roller according to claim 1, which is made of polyvinyl chloride, polystyrene, polyester, or fluororesin. 8. A transfer roller, a developing roller, a toner supplying roller used in an image forming apparatus such as a printer or a copying machine,
The conductive roller according to claim 1, which is a charging roller or a cleaning roller. 9. An image forming apparatus, wherein the conductive roller according to claim 1 is used as a transfer roller, a developing roller, a toner supply roller, a charging roller or a cleaning roller.