JP2003202722A - Conductive roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive roll that steadily obtains a desired resistance value and has stable physical properties. <P>SOLUTION: A conductive rubber member 12 made of a rubbery elastic body containing at least one kind of ionic liquid as a conductive agent is formed round a core member 11, thereby forming the conductive roll 10. <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 conductive roll, and more particularly, to a charging roll / developing roll, a toner regulating roll of an image forming apparatus such as an electrophotographic copying machine and printer, or a toner jet copying machine and printer. Further, the present invention relates to a conductive roll suitable for use as an intermediate transfer roll or a cleaning roll used for charging, discharging and cleaning the intermediate conveyance belt.

[0002]

2. Description of the Related Art A conductive roll such as a charging roll, a developing roll, a transfer roll or a cleaning roll is used in an image forming apparatus such as an electrophotographic copying machine and printer or a toner jet copying machine and printer. .

These conductive rolls have a desired electric resistance obtained by adding a conductive agent to a rubber base material such as polyurethane or epichlorohydrin rubber, and have an electronic conductivity obtained by adding a conductive agent such as conductive carbon black. There are known types, an ion conductive type in which an alkali metal salt such as lithium perchlorate is added (see Patent Documents 1 to 4 etc.), and a hybrid type in which these are combined (for example, Patent Documents 5 to 7 etc.). reference).

[0004]

[Patent Document 1] Japanese Patent Application Laid-Open No. 05-173409 (paragraphs “0014”, “0025”, etc.)

[Patent Document 2] Japanese Patent Laid-Open No. 05-281831 (paragraphs "0018", "0028", etc.)

[Patent Document 3] Japanese Unexamined Patent Publication No. 10-045953 (claims, etc.)

[Patent Document 4] Japanese Unexamined Patent Publication No. 10-039582 (Claims)

[Patent Document 5] Japanese Patent Application Laid-Open No. 06-035298 (Claims)

[Patent Document 6] Japanese Patent Laid-Open No. 08-179592 (Claims)

[Patent Document 7] Japanese Unexamined Patent Publication No. 2000-214659
(Paragraphs "0032" to "0035", etc.)

[0005]

By the way, such a conductive roll, in particular, a charging roll, a developing roll, and a transfer roll are used in contact with the photosensitive drum. It is necessary to have an appropriate rubber hardness in order to be able to do properly, but if you try to impart conductivity with conductive carbon, the rubber hardness will increase, for example,
There are problems that the nip width with respect to the contacted surface such as the photosensitive drum cannot be properly set, and that if a high voltage is applied, electrical and physical destruction occurs. In addition, when a softening agent such as oil or a plasticizer is added to reduce the rubber hardness, there is a problem that the photosensitive drum is contaminated.

On the other hand, when an ionic conductive agent such as lithium perchlorate is used, there is no problem that rubber hardness increases.
There is a problem in that the electrical resistance value depends on the environment, and in particular, in a low temperature and low humidity environment, the resistance value becomes high and deviates from the standard. Further, there is a problem that the electric resistance value increases when continuously energized. Further, since the conductive roll is generally used in pressure contact with the photoconductor drum or the like, there is a problem that the ionic conductive agent contaminates the photoconductor.

In view of such circumstances, it is an object of the present invention to provide a conductive roll which can stably obtain a desired resistance value and has stable physical properties.

[0008]

According to a first aspect of the present invention for solving the above-mentioned problems, a conductive rubber member made of a rubber-like elastic body containing at least one ionic liquid as a conductive agent is provided around a core member. The conductive roll is characterized in that it is provided in the.

According to a second aspect of the present invention, in the first aspect, the rubber-like elastic body has a volume resistivity of 1 × 10 ³ to 1 ×.
The conductive roll has a feature of 10 ¹⁰ Ω · cm.

In a third aspect of the present invention, in the first or second aspect, the ionic liquid has the following general formula (1) to
(4) A conductive roll containing a cation selected from the group represented by (4).

[0011]

[Chemical 5]

(In the formula, R ₁ represents a hydrocarbon group having 4 to 10 carbon atoms, R ₂ and R ₃ represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and may contain a hetero atom. Good, provided that the nitrogen atom contains a double bond, R ₃ is absent.)

[0013]

[Chemical 6]

(In the formula, R ₄ represents a hydrocarbon group having 2 to 10 carbon atoms, and R ₅ , R ₆ , and R ₇ are hydrogen or 1 to 10 carbon atoms.
8 represents an alkyl group and may contain a hetero atom. )

[0015]

[Chemical 7]

(In the formula, R ₈ represents a hydrocarbon group having 2 to 10 carbon atoms, R ₉ and R ₁₀ represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and may contain a hetero atom. good.)

[0017]

[Chemical 8]

(In the formula, Q represents a nitrogen, phosphorus or sulfur atom, and R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ represent hydrogen or an alkyl group having 1 to 8 carbon atoms and include a hetero atom. However, if Q is a sulfur atom, there is no R _11. )

The fourth aspect of the present invention is any one of the first to third aspects.
In the embodiment, the ionic liquid is AlCl_Four ⁻,
Al_TwoCl₇ ⁻, NO_Three ⁻, BF_Four ⁻, PF₆ ⁻, CH
_ThreeCOO⁻, CF_ThreeCOO⁻, CF_ThreeSO_Three ⁻, (CF
_ThreeSO_Two)_TwoN⁻, (CF_ThreeSO_Two)_ThreeC⁻, AsF₆
⁻, SbF₆ ⁻, F (HF) n⁻, CF_ThreeCF_TwoCF _Two
CF_TwoSO_Three ⁻, (CF_ThreeCF_TwoSO_Two)_TwoN⁻, CF
_ThreeCF_TwoCF_TwoCOO ⁻Anion selected from
It is in the conductive roll characterized by including.

A fifth aspect of the present invention is the conductive roll according to any one of the first to fourth aspects, characterized in that the ionic liquid has a melting point of 70 ° C. or lower.

A sixth aspect of the present invention is the conductive roll according to any one of the first to fifth aspects, characterized in that the conductive rubber member is provided with a surface treatment layer.

A seventh aspect of the present invention is the conductive roll according to any one of the first to fifth aspects, characterized in that a surface layer is provided on the surface of the conductive rubber member.

In the present invention, since the ionic liquid is added as the conductive agent, the desired medium resistance value can be stably obtained without increasing the rubber hardness as compared with the case where the conductive carbon is added. Also, compared to the case where an ionic conductive agent such as lithium perchlorate is added, the environmental resistance of the electric resistance value, especially the humidity dependence is low, and since there is no concern that the hygroscopicity will rise, hydrolysis is promoted. Not, and
The conductive roll has the same mechanical properties as those without additives.

Here, the ionic liquid is a molten salt which is a liquid at room temperature, and is also called an ordinary temperature molten salt, and particularly has a melting point of 70 ° C. or lower, preferably 30 ° C. or lower. Such an ionic liquid has properties such as no vapor pressure (nonvolatile), high heat resistance, nonflammability, and chemical stability.

Therefore, unlike an ionic conductive agent, it is less dangerous to handle and is a liquid at room temperature, so that it can be easily added to rubber and a desired medium resistance can be easily obtained. Particularly, in the case of polyurethane, since it may be added as it is to the polyol which is the main raw material, there is an advantage that the addition is easy. Further, since it is not volatile, bleeding does not occur if it is compatible with the rubber even if the number of added parts is increased. In particular, when an ionic liquid that is not soluble in water (hydrophobic ionic liquid) is used, it does not increase the hygroscopicity of polyurethane, so it does not promote hydrolysis, has low humidity dependence, and has stable conductivity. It is thought that.

Ionic liquids that can be used in the present invention
Is a cation represented by the general formula (1) to (4) described above.
(Cationic), for example, imidazo
Cyclic amidine ions, such as the lithium ion, pyridinium
Ion, ammonium ion, sulfonium, phosphoni
It uses organic cations such as um ions as cations.
is there. As the anion, AlCl_Four ⁻, Al_TwoCl₇
⁻, NO_Three ⁻, BF_Four ⁻, PF₆ ⁻, CH_ThreeCOO⁻,
CF_ThreeCOO⁻, CF_ThreeSO_Three ⁻, (CF_ThreeSO _Two)_Two
N⁻, (CF_ThreeSO_Two)_ThreeC⁻, AsF₆ ⁻, SbF₆
⁻, F (HF) n ⁻, CF_ThreeCF_TwoCF_TwoCF_TwoSO_Three
⁻, (CF_ThreeCF_TwoSO_Two)_TwoN⁻, CF _ThreeCF_TwoCF
_TwoCOO⁻And so on.

Specific examples of the ionic liquid include those comprising a combination of an organic cation represented by the following formula and a counter anion represented by the following formula.

[0028]

[Chemical 9]

Abbreviations in the formula EMI: 1-ethyl-3-methylimidazole BP: 1-butylpiperidine P12: N-ethyl-N-methylpyrrolidine

[0030]

[Chemical 10]

Abbreviations in the formula TFSI: bis {(trifluoromethyl) sulfonyl} imide

In the present invention, an ionic liquid compatible with the base rubber-like elastic body may be used and is not particularly limited. The mixing ratio is not particularly limited, but may be, for example, about 0.1 to 30% by weight with respect to the rubber-like elastic substrate.

Some ionic liquids are insoluble in water, and in consideration of stability with respect to humidity, corrosion of metal such as core, and the like, water insoluble ( It is preferable to use a hydrophobic ionic liquid).

The ionic liquid used in the present invention is added to the rubber-like elastic body as a conductive agent, but since it also acts as a softening agent so as to reduce the rubber hardness of the rubber-like elastic body, an oil or a plasticizer is used. It is intended to reduce the electric resistance value while reducing the rubber hardness without adding a softening agent such as.

The material of the rubber-like elastic material of the present invention is not particularly limited as long as it is a rubber material capable of obtaining the characteristics according to the application, but it has been conventionally used from the viewpoint of contamination of the photoreceptor and external physical properties. Polyurethane and epichlorohydrin are preferred. However, unlike the conventional conductive agent, the rubber hardness can be lowered rather than increased to greatly reduce the electric resistance value, so that it is possible to use NBR or the like which has been considered to be unusable in the past.

The rubber hardness of the conductive rubber member made of a rubber-like elastic material to which such an ionic liquid is added may be set according to the application and is not particularly limited. However, in order to obtain a desired nip width for use in contact with the photoconductor drum, the rubber hardness is 60 ° or less, preferably 50 ° or less in JIS A type.

The conductive rubber member may be a solid type without foaming or a foaming type, and is not particularly limited.

The conductive rubber member of the present invention is used depending on the application.
Although it is also different, for example, the electrical resistance at an applied voltage of 100 V
Resistance value (25 ℃) is 10^ThreeΩ-10¹⁰Ω, preferably,
10 ^FourΩ-10⁸Ω is used and such desired
Type and addition of ionic liquid so that the resistance value of
Just set the amount.

In the conductive rubber member of the present invention, an electronic conductive agent such as carbon black or metal powder or an ionic conductive agent such as lithium perchlorate may be used in combination within the range not deviating from the object of the present invention.

The conductive roll of the present invention has a roll-shaped conductive rubber member provided around the core member, and the core member may be inserted and bonded to a separately molded conductive rubber member. A conductive rubber member may be integrally formed around the core member.

FIG. 1 shows an example of the conductive roll of the present invention. As shown in FIG. 1, the conductive roll 10 includes a conductive rubber member 12 around a core member 11 made of, for example, a conductive resin or a metal, which is preferably a metal. It should be noted that the core member 11 and the conductive rubber member 12 may be vulcanized by an adhesive or may be bonded by an adhesive as necessary. When an adhesive is used, a conductive adhesive is used. Although it is preferable to use it, the conductive material may be adhered with an adhesive having no electrical conductivity and then electrically connected with an electrically conductive paint, an electrically conductive adhesive or an electrically conductive sealant.

The conductive roll of the present invention, if necessary,
Surface treatment may be performed or a surface layer may be provided.

Here, the surface treatment is carried out by a surface treatment liquid in which an isocyanate component is dissolved in a solvent, a surface treatment liquid in which at least one solvent-soluble polymer is added to the isocyanate component and dissolved in the solvent, or carbon black in which the isocyanate component is used as a solvent. And a surface treatment liquid in which at least one solvent-soluble polymer and carbon black are added to an isocyanate component and dissolved in a solvent. Such surface treatment is carried out by applying a surface treatment liquid to the surface by various coating methods and impregnation methods, heating the solvent as necessary, and drying and removing.

When the surface treatment with such a surface treatment liquid is carried out, the isocyanate component is impregnated into and permeates the surface layer of the conductive rubber member and is cured, whereby the surface treated layer integrated with the conductive rubber member is formed. Form.

The surface-treated layer thus formed is in a state in which the density of the isocyanate component gradually decreases from the surface toward the inside. The solvent-soluble polymer and the carbon black are not substantially impregnated / permeated, but they are integrally retained in the surface treatment layer when the isocyanate component is effective. Therefore, unlike a general coating layer, there is no problem such as peeling, and the effect of preventing pollution and the effect of lowering the friction coefficient can be expected. Furthermore, when the surface treatment layer is formed from a surface treatment liquid obtained by adding a solvent-soluble polymer such as a fluorine-based polymer or a silicone-based polymer to an isocyanate component, it is formed only from the fluorine-based polymer or the silicone-based polymer. Compared with the coating layer, it is easily elastically deformed and the rubber-like elastic body is less likely to crack.

Further, in such a surface treatment, when the rubber-like elastic material constituting the conductive rubber member contains a urethane bond or a reactive group such as a hydroxyl group, it chemically reacts with the isocyanate component in the surface treatment liquid. It is possible to react and form an integral surface treatment layer. Examples of such a rubber-like elastic material include polyurethane and epichlorohydrin rubber.

Here, as the isocyanate component used in the surface treatment liquid, 2,6-tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPDI), 1,5 -Naphthalene diisocyanate (NDI) and 3,3-dimethyldiphenyl-4,4 '
There may be mentioned isocyanate compounds such as diisocyanate (TODI). In addition to these, dimers or trimers of these isocyanate compounds, and further, those obtained by prepolymerizing the isocyanate compound alone or with a polyol can be used.

Solvents that can be used in the surface treatment liquid of the present invention include ethyl acetate and methyl ethyl ketone (ME
K), toluene, acetone, cyclohexanone, etc., as well as reactive diluents such as 2-hydroxyethyl acrylate, tetrahydrofurfuryl acrylate, 2-
Any polymer component such as hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, and trimethylolpropane triacrylate can be dissolved and is compatible with the isocyanate component.

On the other hand, instead of forming the surface treatment layer, a surface layer may be provided on the surface of the conductive rubber member. Such a surface layer may be formed by a conventionally known method, for example, a coating layer formed by using a general coating agent may be used as the surface layer, and the surface layer may be covered with a separately molded elastic tube or resin tube. The configuration is not particularly limited.

However, in the present invention, it is preferable to provide a surface treatment layer rather than providing such a surface layer. The method of covering the tube or providing the coating layer does not contribute much to the conductivity of the ionic liquid,
This is because the resistance of the surface layer itself greatly contributes, but when the surface treatment layer is provided, only the conductivity of the ionic liquid itself contributes, and the performance of the ionic liquid can be utilized.

[0051]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on Examples, but the present invention is not limited thereto.

(Examples 1 to 5) As an ionic liquid, 1
-Ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (EMITFSI), using epichlorohydrin-ethylene oxide rubber (EC
O) EMITFSI for 100 parts by weight of the base,
0.1 parts by weight, 1 part by weight, 5 parts by weight, 10 parts by weight, 20
Each part by weight was added and kneaded, and pressed under vulcanization conditions of 160 ° C. for 20 minutes to prepare a flat plate having a size of 120 mm × 120 mm and a thickness of 1.0 mm.

(Examples 6 to 10) Flat plates were prepared in the same manner as in Examples 1 to 5 except that an acrylonitrile-butadiene rubber (NBR) base was used instead of the ECO base.

(Examples 11 to 15) 1-Ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (EMITFSI) was used as an ionic liquid, and was added to 100 parts by weight of an ester-based polyol. 5 parts by weight, 1 part by weight, 3 parts by weight, 5 parts by weight, 10
By adding each part by weight, and further adding a chain extender, a cross-linking agent and an isocyanate to cause a mixed reaction, 120 mm
A flat plate having a size of 120 mm and a thickness of 1.0 mm was produced.

Example 16 Instead of EMITFSI, 1-butyl-3-ethylimidazolium bis (trifluoromethylsulfonyl) imide (BMITFS
A flat plate was prepared in the same manner as in Example 1 except that 5 parts by weight of I) was used.

Example 17 A flat plate was prepared in the same manner as in Example 1 except that 5 parts by weight of 1-butylpiperidinium bis (trifluoromethylsulfonyl) imide (BPTFSI) was used instead of EMITFSI.

Example 18 Instead of EMITFSI, N-butyl-N-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide (P ₁₄ TFS) was used.
A flat plate was prepared in the same manner as in Example 1 except that 5 parts by weight of I) was used.

Example 19 A flat plate was prepared in the same manner as in Example 1 except that 5 parts by weight of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF ₄ ) was used instead of EMITFSI.

Example 20 In place of EMITFSI, 3 parts by weight of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF ₄ ) was used, and ECO was used.
A flat plate was prepared in the same manner as in Example 1 except that an acrylonitrile-butadiene rubber (NBR) base was used instead of the base.

COMPARATIVE EXAMPLE 1 For comparison, EMITFSI
A flat plate was prepared in the same manner as in Example 1 except that was not added.

Comparative Example 2 A flat plate was prepared in the same manner as in Example 6 except that EMITFSI was not added.

Comparative Example 3 A flat plate was prepared in the same manner as in Example 11 except that EMITFSI was not added.

(Comparative Examples 4 to 9) Except that carbon black was added in place of EMITFSI in an amount of 0.1 part by weight, 1 part by weight, 5 parts by weight, 10 parts by weight, 15 parts by weight and 20 parts by weight, respectively. A flat plate was prepared in the same manner as in Example 1 (ECO).

Comparative Examples 10 to 14 Examples were carried out except that 0.1 part by weight, 1 part by weight, 5 parts by weight, 10 parts by weight and 20 parts by weight of sodium trifluoroacetate were added instead of EMITFSI. A flat plate was prepared in the same manner as in 1.

(Comparative Examples 15 to 20) Carbon black was used in place of EMITFSI in an amount of 0.1 part by weight, 1 part by weight,
A flat plate was prepared in the same manner as in Example 6 (NBR) except that 5 parts by weight, 10 parts by weight, 15 parts by weight, and 20 parts by weight were added, respectively.

Comparative Examples 21 to 25 Examples except that sodium trifluoracetate was added in place of EMITFSI in an amount of 0.1 part by weight, 1 part by weight, 5 parts by weight, 10 parts by weight, and 20 parts by weight, respectively. A flat plate was prepared in the same manner as 6 (NBR).

(Comparative Examples 26 and 27) Flat plates were prepared in the same manner as in Example 11 (U) except that 0.5 parts by weight and 1 part by weight of carbon black were added instead of EMITFSI.

COMPARATIVE EXAMPLE 28 Example 1 was repeated except that 3 parts by weight of lithium perchlorate was added instead of EMITFSI.
A flat plate was prepared in the same manner as 1 (U).

(Test Example 1) Regarding the flat plates of Examples 1 to 15 and Comparative Examples 1 to 27, the temperature was 23 ° C. and the relative humidity was 50%.
The volume resistivity was measured in the normal temperature and normal humidity environment. To measure the volume resistivity, each sample was left in the chamber under the environment for a predetermined time, and then a brass electrode and a current measuring device were used to apply a DC voltage of 100 V in accordance with JIS K6723. The current value after charging for a minute was measured.
Then, the volume resistivity was calculated from the following formula. The main electrode has a diameter of 50 mm and a height of 35 mm, the guard electrode has an outer diameter of 80 mm, an inner diameter of 70 mm, a height of 10 mm, and the counter electrode has a width of 30 mm.
The one having a size of 0 × 150 × 2 mm was used.

[0070]

## EQU1 ## ρ = (πd ² / 4t) Rv ρ: Volume resistivity (Ω · cm) d: Diameter of main electrode (cm) t: Thickness of test piece (cm) Rv: Volume resistance (Ω)

The results are shown in FIGS.

As a result, in the examples using the ionic liquid, since the volume resistivity (logarithmic value) gradually decreased with respect to the number of added parts, it was easy to obtain the target resistance value. In the examples, there was no decrease in resistance up to a certain number with respect to the number of added parts, and when added thereafter, there was a tendency that the resistance rapidly decreased. Further, in the comparative example using the alkali metal ion, the volume resistivity gradually decreased as in the example using the ionic liquid with respect to the number of parts added, but the degree of resistance decrease was poor, and the rubber added with 5 parts or more was used. Then, there was a problem that it would bloom if left for a few days. Therefore, compared with the comparative example using carbon black and the comparative example using alkali metal ions, the example using the ionic liquid is capable of lowering the resistance with a small number of copies, and the target resistance Since it is easy to obtain a value and has good compatibility with rubber, it was found that there is no problem of bloom or bleed, which is a concern with alkali metal ions.

Test Example 2 The water content of various ionic liquids was measured by Karl Fischer. Three
The water content of the ionic liquid left to stand in a high temperature and high humidity environment of 5 ° C. and 85% was measured for each elapsed day, and the saturated water content was measured.
The result is shown in FIG.

From this result, the water content of the hydrophobic ionic liquid was saturated at about 1.5%, but the water content of the ionic liquid soluble in water (hydrophilic ionic liquid) EMIBF ₄ was 30%. As described above, it has been found that when the hydrophilic ionic liquid is left under high temperature and high humidity, it absorbs moisture. For this reason, it has been found that the hydrophilic ionic liquid-containing rubber has a problem that the core splashes and the oxidation of the metal such as the mold is promoted.

(Test Example 3) Examples 4, 6, 9, 14, 1
6 to 19 and Comparative Examples 1, 8, 14, 20, 25, 26,
With respect to the 28 flat plates, the temperature was 35 ° C., the relative humidity was changed from 30% to 80%, and the volume resistivity after standing for 5 hours in each environment was similarly measured. The results are shown in FIGS.

As a result, it was found that when the ionic liquid was used, the humidity dependency was smaller than that when the alkali metal ion was used, regardless of the base rubber material.

Further, it can be seen from FIG. 9 that even if the kind of the ionic liquid is changed, the tendency of the humidity dependence is equally small, and the humidity dependence is similarly low in Example 19 using the hydrophilic ionic liquid. I understood.

In Examples 19 (ECO base) and 20 (NBR base) using the hydrophilic ionic liquid, generation of rust was slightly observed on the rolls kneaded with the rubber.

(Test Example 4) Examples 5, 9, 13, 19,
20 and Comparative Examples 1, 2, 9, 14, 19, 25, 2
For 6 and 28 flat plates, temperature 10 ° C, relative humidity 20%
Low temperature and low humidity environment (LL), temperature 25 ℃, relative humidity 50%
Normal temperature and normal humidity environment (NN), temperature 35 ℃, humidity 85%
The volume resistivity was similarly measured in each of the high temperature and high humidity environment (HH). The results are shown in FIGS.

From these results, the base rubber materials ECO, U
It was found that the environment dependence of the hydrophobic ionic liquid was smaller than that of the alkali metal ion.

When a hydrophilic ionic liquid is used, the ECO of the base rubber has a high environmental dependency equivalent to that of the alkali metal ion as shown in FIG. As shown in 11, it was found that the same environmental dependence as that of the hydrophobic ionic liquid was exhibited.

When NBR is used as the base rubber material, when the environment is changed from LL to NN to HH, alkali metal ions bloom on the surface, and an accurate volume resistivity value cannot be measured. Met.

(Test Example 5) For the flat plates of Examples 3, 9, 15 and Comparative Examples 8, 13, 20, 24, 26, 28,
In a normal temperature and normal humidity environment with a temperature of 23 ° C and a relative humidity of 50%,
The applied voltage was changed from 10 V to 1000 V, and the volume resistivity was measured in the same manner. The results are shown in FIGS.

From these results, it was found that when the ionic liquid was used, the voltage dependence was smaller than when carbon black was used, regardless of the base rubber material.

(Test Example 6) Examples 1 to 15 and Comparative Examples 1 to 1
Hardness Hs (JIS K6253) for 7, 9 to 28
Type A), impact resilience Rb (JIS K6255),
Tensile strength Tb and elongation at break Eb (JIS K62
51), tear strength Tr (JIS K6252), and compression set Cs were measured. The results are shown in Tables 1 to 3.

[0086]

[Table 1]

[0087]

[Table 2]

[0088]

[Table 3]

As a result, regardless of the base rubber material, in the comparative example in which carbon black was added, a large increase in hardness was observed as the number of added parts increased, and the tensile strength accordingly increased. Also in the comparative example using the alkali metal ion, the impact resilience was decreased irrespective of the base rubber material, but in the example in which the ionic liquid was blended at 10 phr or less, it was almost the same as the additive-free one. It was found that the physical properties of

(Example 21) (Production of roll) An ionic liquid EMITFSI as a conductive agent was added to 100 parts by weight of epichlorohydrin rubber.
1.5 parts by weight, zinc oxide (ZnO) 5 parts by weight, 2-mercaptoimidazoline (Axel-22) as a vulcanizing agent
3 parts by weight were kneaded with a roll mixer and press-formed on the surface of a metal shaft (core member) having a diameter of 6 mm to give a diameter of 1
It was ground to 2 mm to obtain a roll having a conductive rubber member formed on the shaft surface.

(Preparation of Surface Treatment Liquid) An ethyl acetate solution containing 15% by weight of an isocyanate compound (MDI: manufactured by Dainippon Ink and Chemicals) in ethyl acetate was dispersed and mixed for 15 minutes to obtain a surface treatment liquid.

(Surface treatment of roll)
After keeping the roll at 30C for 30 seconds,
The surface-treated conductive roll was obtained by heating for 1 hour in an oven maintained at 0 ° C.

(Example 22) (Production of roll) 3 parts by weight of a foaming agent, 2 parts by weight of a foaming aid, 3 parts by weight of an inorganic foaming agent, 100 parts by weight of epichlorohydrin rubber, and an ionic liquid as a conductive agent. EMIT
FSI 1.5 parts by weight, zinc oxide (ZnO) 5 parts by weight, and 2-mercaptoimidazoline (Axel-
22) 3 parts by weight are kneaded with a roll mixer and the diameter is 6 mm.
By press molding on the surface of the metal shaft, a foamed rubber elastic member was formed as a conductive rubber member on the surface of the shaft.
A 0.5 mm conductive rubber tube was set on the surface layer and subjected to polishing to a diameter of 12 mm to obtain a conductive low hardness roll.

(Comparative Example 29) A roll was obtained in the same manner as in Example 21, except that the ionic liquid was not added.

Comparative Example 30 A roll was obtained in the same manner as in Example 21, except that 20 parts by weight of carbon black (Toka Black # 5500: manufactured by Tokai Carbon Co., Ltd.) was used instead of the ionic liquid.

Comparative Example 31 A roll was obtained in the same manner as in Example 21, except that sodium trifluoroacetate was used in 0.8 parts by weight instead of the ionic liquid.

Test Example 7 Measurement of Electric Resistance Value Regarding the conductive rolls of Examples 21 and 22 and Comparative Examples 29 to 31, the electric resistance value of the roll was measured under the environment of temperature 23 ° C. and relative humidity 55%. The resistance value of the conductive roll was measured by the method shown in FIG. That is, the conductive rubber member 12 of the conductive roll 10 is placed on the electrode member 21 made of the SUS304 plate, and the conductive rubber member 12 is attached to both ends of the core metal 11 by 5 mm.
The core metal 11 and the electrode member 2 with a load of 00g weight applied.
The resistance value between 1 and ULTRA HIGH RESIS
It measured using TANSEMETER R8340A (made by Advantest Corporation). The applied voltage at this time was 100V. Further, the volume resistivity (log (Ω · cm)) value was also calculated using the following formula. The results are shown in Table 4.
Shown in.

[0098]

[Equation 2]

Test Example 8 Environmental Dependence Test Regarding the conductive rolls of Examples 21 and 22 and Comparative Examples 29 to 31, a low temperature and low humidity environment (LL) at a temperature of 10 ° C. and a relative humidity of 30%, a temperature of 23 ° C., a relative temperature. The volume resistivity of the roll was measured when the roll was held for 12 hours in each of the normal temperature and normal humidity environment (NN) having a humidity of 55% and the high temperature and high humidity environment (HH) having a temperature of 30 ° C. and a humidity of 85%. The volume resistivity was measured in the same manner as in Test Example 7, and the applied voltage was 100 V and 500.
It was measured as V. The results are shown in FIGS. 17 and 18.

From these figures, in the example using the ionic liquid, the volume resistivity (log (Ω · cm)) when changing from the LL environment to the HH environment was within one digit, and the environmental dependence was high. It was found to be low. On the other hand, the volume resistivity (log (Ω · cm)) of the comparative example 31 using alkali metal ions and the volume resistivity (log (Ω · cm)) changed by two digits when changing from the LL environment to the HH environment, and even in the comparative example 29 containing no conductive agent. Since it changed by a little less than two orders of magnitude, it was found that Examples 21 and 22 using the ionic liquid had a lower environmental dependency than Comparative Examples 29 and 31.

Test Example 9 Voltage Dependence Test The conductive rolls of Example 21 and Comparative Examples 29 to 31 were subjected to room temperature and normal humidity at a temperature of 23 ° C. and a relative humidity of 55%.
In the same manner as in Test Example 7, the electric resistance value was set to 10V and 10V.
The applied voltage of 0V, 500V, and 1000V was changed and measured, and the volume resistivity value was similarly obtained. This result is shown in FIG.
Shown in.

From FIG. 19, it was confirmed that the roll of Example 1 using the ionic liquid had no voltage dependence.

(Test Example 10) Roll surface damage test The conductive rolls of Example 21 and Comparative Examples 29 to 31 were assembled in a toner cartridge of a commercially available laser printer, and each cartridge was exposed to an environment of 50 ° C. and 90% RH.
After holding for 4 days, the cartridge and the conductive roll were assembled as a charging roll in a printer to output an image.
Then the images were compared. The results are also shown in Table 4. At the same time, the rubber hardness of the roll is also shown in Table 4.

From the results shown in Table 4, the image and the roll surface of the charging roll of Example 21 were not changed as compared with those before the holding, whereas the roll of Comparative Example 31 using the alkali metal ion showed no change on the roll surface. Bloom was seen and the image was also degraded. In Comparative Example 30 using carbon black, the roll surface did not change, but the roll hardness was 6
As high as 4 °, deterioration of the image was observed.

[0105]

[Table 4]

[0106]

As described above, according to the present invention, since an ionic liquid is used as a conductive agent, it is possible to set a desired resistance value relatively easily, there is no physical property change and humidity dependency, and there is no environmental change. It is possible to provide a medium resistance rubber member having low dependency and voltage dependency.

[Brief description of drawings]

FIG. 1 is a diagram showing a conductive roll according to an embodiment of the present invention.

FIG. 2 is a graph showing the results of Test Example 1.

FIG. 3 is a graph showing the results of Test Example 1.

FIG. 4 is a graph showing the results of Test Example 1.

FIG. 5 is a graph showing the results of Test Example 2.

FIG. 6 is a graph showing the results of Test Example 3.

FIG. 7 is a graph showing the results of Test Example 3.

FIG. 8 is a graph showing the results of Test Example 3.

FIG. 9 is a graph showing the results of Test Example 3.

FIG. 10 is a graph showing the results of Test Example 4.

FIG. 11 is a graph showing the results of Test Example 4.

FIG. 12 is a graph showing the results of Test Example 4.

FIG. 13 is a graph showing the results of Test Example 5.

FIG. 14 is a graph showing the results of Test Example 5.

FIG. 15 is a graph showing the results of Test Example 5.

16 is a diagram showing a state of measuring an electric resistance value in Test Example 7. FIG.

FIG. 17 is a graph showing the results of Test Example 8.

FIG. 18 is a graph showing the results of Test Example 8.

FIG. 19 is a graph showing the results of Test Example 9.

[Explanation of symbols]

10 Conductive roll 11 Core member 12 Conductive rubber member

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 5/36 C08K 5/36 4F006 5/50 5/50 4J002 C08L 21/00 C08L 21/00 5G301 F16C 13 / 00 F16C 13/00 B E G03G 15/02 101 G03G 15/02 101 15/08 501 15/08 501D 504 504D 15/16 103 15/16 103 21/10 H01B 1/20 Z // H01B 1/20 G03G 21/00 312 (72) Naoki Hirakawa Inventor Naoki Hirakawa 2-3-6 Shirute, Tsurumi-ku, Yokohama-shi, Kanagawa Kitatsu Industry Co., Ltd. (72) Kazumi Kanai 2-3-6 Shirute, Tsurumi-ku, Yokohama-shi, Kanagawa No. Hokushin Kogyo Co., Ltd. (72) Inventor Mayumi Nakao 2-3-6 Shirate, Tsurumi-ku, Yokohama-shi Kanagawa Hokushin Kogyo Co., Ltd. (72) Inventor Masayoshi Watanabe 2-190-3-401 F term, Nishitobe-cho, Nishi-ku, Yokohama-shi, Kanagawa Prefecture (reference) 2H077 AD06 AD14 FA13 FA16 FA22 FA25 GA02 GA03 2H134 GA01 GA09 GA10 GB02 HA01 HA03 HA04 HA05 KG01 KG03 KG04 KG07 KG08 KH04 KH15 2H171 FA11 FA13 FA17 FA30 GA24 GA25 QB03 QB07 QB47 QC23 QC25 TA02 TA03 TA04 TB12 TB13 UA02 UA03 UA12 UA22 VA01 VA05 XA02 2H200 FA01 FA02 HA03 HA28 HB12 HB22 HB45 HB46 HB47 JA02 JA21 JA25 JA26 JA27 JC02 JC03 JC12 JC15 JC16 JC17 LB15 LB35 LB36 LB37 LC02 LC09 MA01 MA03 MA20 MB01 MB04 MB06 MC01 MC02 MC03 3J103 AA02 AA32 AA85 BA41 FA18 GA02 GA57 GA58 HA03 HA12 HA20 HA54 4F006 AA04 AA31 AB37 AB65 AB72 BA09 BA11 CA08 4J002 AC071 CH041 CK021 EN136 EU0276176046 5G301 DA22 DA28 DA42 DD10

Claims (7)

[Claims] 1. A conductive roll, characterized in that a conductive rubber member made of a rubber-like elastic body containing at least one ionic liquid as a conductive agent is provided around a core member. 2. The conductive roll according to claim 1, wherein the rubber-like elastic body has a volume resistivity of 1 × 10 ³ to 1 × 10 ¹⁰ Ω · cm. 3. The conductive roll according to claim 1, wherein the ionic liquid contains a cation selected from the group represented by the following general formulas (1) to (4). [Chemical 1] (In the formula, R ₁ represents a hydrocarbon group having 4 to 10 carbon atoms,
R ₂ and R ₃ represent hydrogen or an alkyl group having 1 to 8 carbon atoms and may contain a hetero atom. However, when the nitrogen atom contains a double bond, there is no R ₃ . ) [Chemical 2] (In the formula, R ₄ represents a hydrocarbon group having 2 to 10 carbon atoms,
R ₅ , R ₆ , and R ₇ represent hydrogen or an alkyl group having 1 to 8 carbon atoms and may contain a hetero atom. ) [Chemical 3] (In the formula, R ₈ represents a hydrocarbon group having 2 to 10 carbon atoms,
R ₉ and R ₁₀ represent hydrogen or an alkyl group having 1 to 8 carbon atoms and may contain a hetero atom. ) [Chemical 4] (In the formula, Q represents a nitrogen, phosphorus, or sulfur atom, and R ₁₁ ,
R ₁₂ , R ₁₃ , and R ₁₄ represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and may contain a hetero atom. However, when Q is a sulfur atom, there is no R ₁₁ . ) 4. The method according to claim 1, wherein
On-liquid is AlCl_Four ⁻, Al_TwoCl₇ ⁻, NO_Three
⁻, BF_Four ⁻, PF₆ ⁻, CH_ThreeCOO⁻, CF_ThreeCO
O⁻, CF_ThreeSO_Three ⁻, (CF_ThreeSO_Two)_TwoN⁻, (C
F_ThreeSO_Two) _ThreeC⁻, AsF₆ ⁻, SbF₆ ⁻, F (H
F) n⁻, CF_ThreeCF_TwoCF_TwoCF_TwoSO_Three ⁻, (CF
_ThreeCF_TwoSO_Two)_TwoN⁻, CF_ThreeCF_TwoCF_TwoCOO⁻
An anion selected from among
Electrical roll. 5. The conductive roll according to claim 1, wherein the ionic liquid has a melting point of 70 ° C. or lower. 6. The conductive roll according to claim 1, wherein the conductive rubber member comprises a surface treatment layer. 7. The conductive roll according to claim 1, wherein a surface layer is provided on the surface of the conductive rubber member.