JP2021128296A - Method for manufacturing intermediate transfer body and intermediate transfer body - Google Patents

Abstract

To provide a method for manufacturing an intermediate transfer body including a ferroelectric material and a carbon nano-tube, the intermediate transfer body attaining reduction of resistance unevenness and acquisition of an image with less image unevenness, and to provide the intermediate transfer body.SOLUTION: A method for manufacturing an intermediate transfer body of the present invention is a method for manufacturing an intermediate transfer body including a carbon nano-tube and a ferroelectric material. The method includes: a step (A) of mixing the carbon nano-tube, a resin, and a solvent and obtaining carbon nano-tube dispersion liquid; a step (B) of mixing the ferroelectric material, a resin, and a solvent and obtaining ferroelectric material dispersion liquid; and a step (C) of mixing the carbon nano-tube dispersion liquid obtained in the step (A) and the ferroelectric material dispersion liquid obtained in the step (B) and forming an obtained application solution into a film and drying the film.SELECTED DRAWING: None

Description

The present invention relates to a method for producing an intermediate transfer body and an intermediate transfer body, and particularly in an intermediate transfer body containing a ferroelectric substance and carbon nanotubes, intermediate transfer capable of suppressing resistance variation and obtaining an image with less image unevenness. Regarding the manufacturing method of the body.

In recent years, in electrophotographic image formation, improvement in transfer performance has been required by expanding applications to various media such as uneven paper. As a method for that purpose, a method of adding a ferroelectric substance to the intermediate transfer body to increase the dielectric constant of the intermediate transfer body has been proposed (see, for example, Patent Document 1).
In the above case, there is a concern that the strength of the intermediate transfer material will be weakened by adding the ferroelectric substance. In order to secure the strength, it is effective to reduce the amount of the ferroelectric substance added.
Therefore, it has been proposed to use carbon nanotubes (hereinafter, also referred to as CNT) as the conductive filler (conductor) of the intermediate transfer material. CNT has higher conductive performance than carbon black or the like, and can impart the required conductive performance with a small amount of addition.

However, it is generally difficult to uniformly disperse CNTs. As a method for improving the dispersibility of CNTs, for example, as disclosed in Patent Document 2, a method of pre-dispersing CNTs in advance has been proposed.
However, as a result of diligent research, the present inventors have found that the conductive filler tends to aggregate around the ferroelectric substance. Therefore, when a ferroelectric substance is added by the method disclosed in Patent Document 2 (when a pre-dispersed CNT is added in the step of kneading the ferroelectric substance), the ferroelectric substance is once dispersed due to the presence of the ferroelectric substance. The agglomerated CNTs are agglomerated again, and the agglomeration of the CNTs is more likely to occur. As a result, there is a problem that the electrical resistance varies in the plane of the intermediate transfer body and the image unevenness becomes large.

Japanese Unexamined Patent Publication No. 8-152759 Japanese Unexamined Patent Publication No. 2005-62474

The present invention has been made in view of the above problems and situations, and the problem to be solved is to suppress resistance variation and obtain an image with less image unevenness in an intermediate transfer material containing a ferroelectric substance and carbon nanotubes. It is an object of the present invention to provide a method for producing an intermediate transcript and an intermediate transcript capable of producing the same.

In order to solve the above problems, the present inventor prepares a dispersion liquid by mixing carbon nanotubes, a resin and a solvent in advance in the process of examining the cause of the above problems, and separately obtains a strong dielectric and a resin. And a solvent are mixed to obtain a dispersion liquid, and then both dispersion liquids are mixed to form a coating liquid, which is formed and dried to suppress resistance variation and obtain an image with less image unevenness. We found what we could do and came up with the present invention.
That is, the above problem according to the present invention is solved by the following means.

1. 1. A method for producing an intermediate transfer material containing carbon nanotubes and a ferroelectric substance.
The step (A) of mixing the carbon nanotubes, the resin, and the solvent to obtain a carbon nanotube dispersion liquid,
The step (B) of mixing the ferroelectric substance, the resin, and the solvent to obtain a ferroelectric dispersion liquid.
A step (C) of mixing the carbon nanotube dispersion liquid obtained in the step (A) with the ferroelectric dispersion liquid obtained in the step (B), and forming and drying the obtained coating liquid. A method for producing an intermediate transfer material, which comprises.

2. In the step (A), the solvent dispersion liquid obtained by dispersing the carbon nanotubes in a solvent and the resin solution obtained by dissolving the resin in a solvent are mixed to form the carbon nanotube dispersion liquid. The method for producing an intermediate transcript according to the first item, which comprises obtaining.

3. 3. In the step (B), the solvent dispersion liquid obtained by dispersing the ferroelectric substance in a solvent and the resin solution obtained by dissolving the resin in a solvent are mixed to obtain the ferroelectric substance. The method for producing an intermediate transfer product according to the first or second paragraph, which comprises obtaining a dispersion liquid.

4. Any of the items 1 to 3, wherein the carbon nanotube concentration of the carbon nanotube dispersion liquid obtained in the step (A) is in the range of 0.16 to 0.60% by mass. The method for producing an intermediate transfer material according to item 1.

5. An intermediate transfer material containing carbon nanotubes and a ferroelectric substance.
An intermediate transfer product characterized in that the dispersion V, which is an index of logarithmic variation of the surface resistivity at a plurality of in-plane locations, is 0.015 or less.

6. The intermediate transfer member according to item 5, wherein the relative permittivity of the intermediate transfer body at a frequency of 1 MHz is in the range of 10 to 60.

7. The intermediate transfer product according to item 5 or 6, wherein the content of the ferroelectric substance is in the range of 5 to 25% by volume.

8. The intermediate transfer product according to any one of items 5 to 7, wherein the content of the carbon nanotubes is in the range of 0.3 to 2.0% by volume.

9. The intermediate transfer material according to any one of items 5 to 8, wherein the ferroelectric substance contains barium titanate or strontium titanate.

10. The intermediate transfer product according to any one of items 5 to 9, wherein the average diameter of the carbon nanotubes is in the range of 5 to 50 nm.

11. The intermediate transfer product according to any one of items 5 to 10, wherein the average length of the carbon nanotubes is in the range of 0.1 to 50 μm.

12. The intermediate transfer material according to any one of items 5 to 11, wherein a surface layer is provided on the layer containing the carbon nanotubes and the ferroelectric substance.

According to the above means of the present invention, there is provided a method for producing an intermediate transfer body and an intermediate transfer body capable of suppressing resistance variation and obtaining an image with less image unevenness in an intermediate transfer body containing a ferroelectric substance and carbon nanotubes. be able to.
Although the mechanism of expression or mechanism of action of the effects of the present invention has not been clarified, it is inferred as follows.
In advance, the carbon nanotubes are dispersed in the resin and the solvent, and the ferroelectric substance is also dispersed in the resin and the solvent. As a result, it is presumed that the dispersibility of each is maintained even after the carbon nanotube dispersion liquid and the ferroelectric dispersion liquid are mixed, and the dispersibility of the carbon nanotubes when belted as an intermediate transfer material is improved. As a result, it is possible to obtain an image having a small resistance variation and excellent quality in which image unevenness is suppressed.

Conceptual cross-sectional view showing an example of the layer structure of the intermediate transfer member of the present invention. Schematic diagram showing the structure of the image forming apparatus of the present invention Block diagram showing the configuration of the image forming apparatus of the present invention Block diagram showing the configuration of the image forming apparatus of the present invention Schematic diagram for explaining the method of measuring the dielectric constant

The method for producing an intermediate transfer material of the present invention is a method for producing an intermediate transfer material containing carbon nanotubes and a strong dielectric, in which the carbon nanotubes, a resin, and a solvent are mixed to form a carbon nanotube dispersion liquid. (A), the step (B) of mixing the strong dielectric, the resin, and the solvent to obtain the strong dielectric dispersion, and the carbon nanotube dispersion obtained in the step (A). And the step (C) of mixing the strong dielectric dispersion liquid obtained in the step (B) and forming and drying the obtained coating liquid.
This feature is a technical feature common to or corresponding to each of the following embodiments.

In an embodiment of the present invention, in the step (A), a solvent dispersion liquid obtained by dispersing the carbon nanotubes in a solvent and a resin solution obtained by dissolving the resin in a solvent are mixed. Therefore, it is preferable to obtain the carbon nanotube dispersion liquid from the viewpoint of further improving the dispersibility of the carbon nanotubes.
Further, in the step (B), the solvent dispersion liquid obtained by dispersing the ferroelectric substance in a solvent and the resin solution obtained by dissolving the resin in a solvent are mixed to obtain the strength. It is preferable to obtain a dielectric dispersion liquid in that the dispersibility of the ferroelectric substance is further improved.

The carbon nanotube concentration of the carbon nanotube dispersion liquid obtained in the step (A) is preferably in the range of 0.16 to 0.60% by mass. The reason is that if it is lower than 0.16% by mass, the solid content concentration of the coating liquid becomes too low in the subsequent step of preparing the coating liquid, and if it is higher than 0.60% by mass, the dispersion liquid This is because the higher the viscosity, the worse the handleability.

The intermediate transfer material of the present invention is an intermediate transfer material containing carbon nanotubes and a ferroelectric substance, and has a dispersion V of 0.015 or less, which is a logarithmic variation index of surface resistivity at a plurality of in-plane locations. It is characterized by being. As a result, resistance variation can be suppressed, and an image with less image unevenness can be obtained.

It is preferable that the relative permittivity of the intermediate transfer body at a frequency of 1 MHz is in the range of 10 to 60 because it is easy to strengthen the transfer electric field.

It is preferable that the content of the ferroelectric substance is in the range of 5 to 25% by volume in that the mechanical strength and the transferability can be further improved.

When the content of the carbon nanotubes is in the range of 0.3 to 2.0% by volume, the surface of the intermediate transfer body is not contaminated with toner, and the strength of the intermediate transfer body and the toner are not contaminated. It is preferable in that no decrease in the amount of charge is observed and the result is good.

It is preferable that the ferroelectric substance contains barium titanate or strontium titanate in that transferability can be improved.

It is preferable that the average diameter of the carbon nanotubes is in the range of 5 to 50 nm in that appropriate conductivity can be imparted to the intermediate transfer material.

Further, it is preferable that the average length of the carbon nanotubes is in the range of 0.1 to 50 μm in that appropriate conductivity can be imparted to the intermediate transfer material.

It is preferable that a surface layer is provided on the layer containing the carbon nanotubes and the ferroelectric substance from the viewpoint of improving the transferability of the intermediate transfer material.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described. In the present application, "~" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

[Method for producing intermediate transcript of the present invention]
The method for producing an intermediate transfer material of the present invention is a method for producing an intermediate transfer material containing carbon nanotubes and a strong dielectric, in which the carbon nanotubes, a resin, and a solvent are mixed to form a carbon nanotube dispersion liquid. (A), the step (B) of mixing the strong dielectric, the resin, and the solvent to obtain the strong dielectric dispersion, and the carbon nanotube dispersion obtained in the step (A). And the step (C) of mixing the strong dielectric dispersion liquid obtained in the step (B) and forming and drying the obtained coating liquid.

<Step (A)>
The step (A) is a step of mixing carbon nanotubes, a resin, and a solvent to obtain a carbon nanotube dispersion liquid.
In particular, the carbon nanotubes are dispersed in a solvent to prepare a solvent dispersion liquid, and the resin is separately dissolved in a solvent to prepare a resin solution, and then the prepared solvent dispersion liquid and the above are described. It is preferable to mix with a resin solution to obtain the carbon nanotube dispersion liquid from the viewpoint of further improving the dispersibility of the carbon nanotubes.

Further, the carbon nanotube concentration in the carbon nanotube dispersion liquid is preferably in the range of 0.16 to 0.60% by mass. The reason is that if it is lower than 0.16% by mass, the solid content concentration of the coating liquid becomes too low in the subsequent step of preparing the coating liquid, and if it is higher than 0.60% by mass, the dispersion liquid This is because the higher the viscosity, the worse the handleability.

(carbon nanotube)
A carbon nanotube (CNT) is a defect-free single-walled substance having a structure in which a graphite hexagonal net plane is rolled into a tubular shape, or a multi-walled tubular substance in which they are laminated in a nested manner.
The average diameter (average tube diameter) of the CNTs contained in the intermediate transfer material of the present invention is preferably in the range of 5 to 50 nm, and more preferably in the range of 5 to 15 nm.
The average length of CNTs is preferably in the range of 0.1 to 50 μm, more preferably in the range of 30 to 50 nm.
By setting the average diameter and the average length of the CNTs in the above ranges, appropriate conductivity can be imparted to the intermediate transfer material.

This CNT may be covalently bonded to a functional group, if necessary. For example, a strong acid treatment of CNT produces an oxidized CNT in which a carboxylic acid is introduced on the surface, and the oxidized CNT is reacted with thionyl chloride and then reacted with an alkyl alcohol or the like to dissolve in an organic solvent. CNT can be generated. By using such chemically decorated CNTs, the CNTs can be uniformly dispersed in the resin. Further, by applying an electric field from the outside with the CNTs dispersed in the resin, the CNTs can be oriented in a desired direction, and the dielectric constant of the intermediate transfer material can be improved.

The average diameter of the CNTs is determined by observing the morphology of the CNTs using a transmission electron microscope (TEM), and for 100 CNTs, various image analysis software (for example, iSpect DIA-10 manufactured by Shimadzu Corporation). The diameter can be measured using, and the average value of these can be calculated to obtain the average value of the diameter of the CNT.
The average length of the CNTs is also measured by observing the morphology of the CNTs using a transmission electron microscope (TEM) and measuring the length (long axis) of 100 CNTs using various image analysis software. Then, the average value of these can be calculated to obtain the average value of the length of the CNT.
The average diameter and average length can be adjusted by cutting (crushing) CNTs, mixing two or more types of CNTs, and the like.

The content of the carbon nanotubes is preferably in the range of 0.3 to 2.0% by volume with respect to the entire intermediate transcript. When it is 0.3% by volume or more, toner is not contaminated on the surface of the intermediate transfer body, and when it is 20% by volume or less, the strength of the intermediate transfer body and the charge amount of the toner are not lowered, which is good. Is. More preferably, it is in the range of 0.5 to 15% by volume, and even more preferably, it is in the range of 1 to 10% by volume.

(resin)
As the resin used in the step (A), various resins can be used, but polyimide (PI), polyamide (PA), polyamideimide (PAI), polyphenylene sulfide (PPS), and polyetheretherketone (PPS). Super engineering plastics with strength and durability such as PEEK) are desirable.

Of these, polyimide, polyamide and polyamideimide are preferred. Among them, polyimide is more preferable because it has excellent properties such as heat resistance, bending resistance, flexibility, and dimensional stability. Polyimide can be obtained, for example, by synthesizing a polyamic acid (polyimide precursor) from an acid anhydride and a diamine compound, and imidizing the polyamic acid by heat or a catalyst.

The acid anhydride used for the synthesis of polyimide is not particularly limited, and for example, biphenyltetracarboxylic acid dianhydride, terphenyltetracarboxylic acid dianhydride, benzophenone tetracarboxylic acid dianhydride, pyromellitic anhydride, and the like. Examples thereof include aromatic tetracarboxylic acid dianhydrides such as oxydiphthalic acid dianhydride, diphenylsulfone tetracarboxylic acid dianhydride, hexafluoroisopropyridene diphthalic acid dianhydride, and cyclobutane tetracarboxylic acid dianhydride.

The diamine compound used in the synthesis of polyimide is not particularly limited, but for example, p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminodiphenylmethane, 4,4'. -Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 3,7 -Diamino-dimethyldibenzothiophene-5,5'-dioxide, 4,4'-diaminobenzophenone, 4,4'-bis (4-aminophenyl) sulfide, 4,4'-diaminobenzanilide, 1,4-bis Examples thereof include aromatic diamines such as (4-aminophenoxy) benzene.

The resin is preferably contained in the range of 50 to 95% by volume with respect to the entire layer containing the CNT and the ferroelectric substance (for example, the base material layer). When it is 50% by volume or more, it can have the required mechanical strength. When it is 95% by volume or less, a space containing a ferroelectric substance or CNT can be secured.

(solvent)
Examples of the solvent used in the step (A) include N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide and the like.
It is preferable to add carbon nanotubes to the solvent at a solid content concentration of 0.25 to 0.5% by mass.

(Distribution method)
As a dispersion method, for example, a bead mill disperser, a mixer or the like can be used for dispersion.
A particle size distribution is used as the variance index. It is preferable to measure the particle size distribution by a dynamic light scattering method and disperse the carbon nanotubes until the fluctuation rate of the average particle size is within 5%. Further, the dispersion index may be changed within a range in which desired physical properties can be obtained.
The average particle size is preferably a median diameter based on the number of pieces, and is preferably measured by a dynamic light scattering method using, for example, "Microtrack UPA-150" (manufactured by Nikkiso Co., Ltd.).
Further, it is preferable that the average particle size is dispersed until the fluctuation rate of the average particle size is within 5% in the step (A), and then the average particle size does not change in the following step (C).
The carbon nanotube dispersion liquid may contain a dispersant to the extent that it does not affect the dielectric constant or the mechanical properties.

<Process (B)>
The step (B) is a step of mixing the ferroelectric substance, the resin, and the solvent to obtain a ferroelectric dispersion liquid.
In particular, a solvent dispersion obtained by dispersing the strong dielectric in a solvent is prepared, and separately, the resin is dissolved in a solvent to prepare a resin solution, and then the obtained resin solution is prepared. It is preferable to mix the solvent dispersion liquid and the resin solution to obtain the strong dielectric dispersion liquid from the viewpoint of further improving the dispersibility of the strong dielectric material.

(Ferroelectric)
In the present invention, a ferroelectric substance is a kind of dielectric, and is a substance in which electric dipoles are aligned even if there is no electric field outside, and the direction of the dipoles can be changed by an electric field. In the present invention, the ferroelectric substance refers to a substance having a relative permittivity of 15 or more at a frequency of 1 MHz in an environment of a temperature of 23 ° C. and a humidity of 50% RH. Preferably, the relative permittivity is 20 or more, more preferably 100 or more. A higher dielectric constant is preferable from the viewpoint of exhibiting the effect of the present invention. The upper limit is constrained by the availability of materials.

Further, the state in which the electric dipole moments are spontaneously aligned in this way is called a ferroelectric state, and this property is called a ferroelectricity. Among the ferroelectric substances, in the present invention, ferroelectric ceramics are desirable as the ferroelectric particles because of the load in the production process and the stability during aged use, and barium titanate, calcium titanate, and titanic acid. Examples thereof include strontium, magnesium titanate, and calcium zirconate. Moreover, you may use these solid solutions as the ferroelectric particles.
Of these, the ferroelectric particles according to the present invention preferably contain barium titanate or strontium titanate, and particularly preferably contain barium titanate in that the dielectric constant can be easily improved.

The method for producing barium titanate is not particularly limited, and for example, it can be produced by the method described in paragraphs 0033 to 0044 of Japanese Patent No. 6368246.
Specifically, an aqueous solution containing barium and titanium hydroxide is prepared, and the aqueous solution is subjected to a hydrothermal reaction under high temperature and high pressure conditions.
The temperature of the hydrothermal reaction is 200 ° C. or higher, preferably 200 to 450 ° C., more preferably 250 to 400 ° C., and the total pressure is 2 MPa or higher, preferably 2 to 50 MPa, more preferably 10 to 40 MPa, usually 0.1. The reaction may be carried out for a minute or more, preferably 0.1 minutes to 1 hour, more preferably 0.1 to 30 minutes. Then, after filtering and washing with water, the particles are dried and crushed to obtain barium titanate particles.
The method for producing strontium titanate is not particularly limited, and the strontium titanate can be produced by the same method as barium titanate described above.

(Average primary particle size of ferroelectric particles)
The average primary particle size of the ferroelectric particles used in the present invention is preferably 300 nm or less in that the residual polarization can be reduced. The lower limit of the average primary particle size is 30 nm, more preferably 50 nm, and the optimum range is in the range of 90 to 110 nm.
For the measurement of the average primary particle size of the ferroelectric particles, 200 or more particles were randomly measured using a transmission electron microscope (TEM) (manufactured by Hitachi High-Technologies Corporation), and the average value was obtained. When the shape of the particles is not spherical, the average value of the major axis and the minor axis can be calculated as the diameter of each particle.
As a means for setting the average primary particle size of the ferroelectric particles within the above range, for example, in the above-mentioned method for producing barium titanate, the type of raw material in an aqueous solution containing barium and titanium hydroxide, Ba. This can be done by controlling the / Ti ratio, the amount of alkali, the reaction scale, the reaction temperature, the reaction pressure, the reaction time, and the like.

The ferroelectric particles are preferably contained in the range of 5 to 25% by volume with respect to the entire intermediate transfer material. When it is 5% by volume or more, there is a high dielectricing effect of the intermediate transfer material, that is, an effect of improving transferability. When it is 25% by volume or less, it can have the required mechanical strength.

As the resin used in the step (B), the same resin as the resin used in the step (A) can be preferably used.
Further, as the solvent used in the step (B), the same solvent as that used in the step (A) can be preferably used.

(Distribution method)
As the dispersion method, as in the dispersion method of the step (A), for example, a bead mill disperser, a mixer, or the like can be used for dispersion.
A particle size distribution is used as the variance index. It is preferable to measure the particle size distribution by a dynamic light scattering method and disperse the ferroelectric particles until the fluctuation rate of the average particle size is within 5%. Further, the dispersion index may be changed within a range in which desired physical properties can be obtained.
The average particle size is preferably a median diameter based on the number of pieces, and is preferably measured by a dynamic light scattering method using, for example, "Microtrack UPA-150" (manufactured by Nikkiso Co., Ltd.).
Further, it is preferable that the average particle size is dispersed until the fluctuation rate of the average particle size is within 5% in the step (B), and then the average particle size does not change in the following step (C).
As the ferroelectric dispersion liquid, a dispersant may be used to the extent that it does not affect the dielectric constant or the mechanical properties.

<Process (C)>
In the step (C), the carbon nanotube dispersion liquid obtained in the step (A) and the ferroelectric dispersion liquid obtained in the step (B) are mixed, and the obtained coating liquid is formed into a film. And the drying process.

(mixture)
As a mixing method, for example, a wing stirring type mixing mixer or the like can be used.
The carbon nanotube dispersion liquid and the ferroelectric dispersion liquid to be mixed in this step are both dispersed in a solvent resin solution. Therefore, it is considered that the dispersion stability is unlikely to be lost even if both are mixed. For example, if both or one of them is a dispersion liquid dispersed only in a solvent, the dispersibility may be lost.

(Film formation)
As a film forming method, for example, while rotating a cylindrical mold made of stainless steel around a cylindrical shaft and moving a dispense nozzle in the axial direction, the coating liquid obtained above is discharged from the nozzle. , Can be spirally applied on the outer peripheral surface of the mold to form a coating film in which they are connected.

(Dry)
As a drying method, most of the solvent is volatilized by heating the cylindrical mold at 130 ° C. for 1 hour while rotating the mold, and then by heating at 350 ° C. for 1 hour, carbon nanotubes and ferroelectrics are applied to the entire resin. It is possible to form an endless belt-shaped intermediate transfer body in which dielectric particles are dispersed.

The intermediate transfer body produced by the above method may be a base material layer of the intermediate transfer body and may be an intermediate transfer body composed of only the base material layer, or an elastic layer or a surface layer may be further bonded to the base material layer. It may be used as an intermediate transcript.
Further, the above method may be adopted for the elastic layer instead of the base material layer, but in the present invention, it is preferably adopted for the base material layer. A known method may be used for forming the elastic layer and the surface layer, and the method is not particularly limited. Details of the elastic layer and the surface layer will be described later.

[Intermediate transcript]
The intermediate transfer material produced by the method for producing an intermediate transfer material of the present invention has a dispersion V of 0.015 or less, which is a logarithmic variation index of the surface resistance of a plurality of in-plane points of the intermediate transfer material. It is characterized by. Preferably, the dispersion V is 0.010 or less.

<Dispersion V>
In the method for measuring the surface resistivity, after allowing the intermediate transfer material to stand for 24 hours in an environment of 23 ° C. and 55% relative humidity, the surface resistivity at a plurality of locations on the surface of the intermediate transfer material is measured by an electrical resistivity measuring instrument (Mitsubishi). Measurement is performed by the 4-terminal method using a high-resistor UP (MCP-HT450) manufactured by Chemical Analytech Co., Ltd.
The squared value of the difference between the measured data at each of the plurality of locations and the average value of all the data is summed, and the value divided by the number of data is defined as the variance V.
The number of measurement points may be a plurality of points, but is preferably 10 or more.

<Relative permittivity>
The intermediate transfer material of the present invention preferably has a relative permittivity at a frequency of 1 MHz in the range of 10 to 60 under an environment of a temperature of 23 ° C. and a humidity of 50% RH.
When the relative permittivity is 10 or more, it is easy to increase the transfer electric field, which is preferable. On the other hand, when the relative permittivity is 60 or less, the adhesive force between the toner and the intermediate transfer body does not become too large, and the transfer efficiency does not decrease, which is preferable. The relative permittivity is more preferably in the range of 30 to 40.

The relative permittivity can be measured by the following method.
The dielectric constant is measured for the intermediate transfer material. Specifically, as shown in FIG. 5, a thin film electrode 201 having a resistance of 1 digit Ω is formed on both sides of the intermediate transfer body 87a by sputtering or the like, and cut out with a mold of 10 mmφ to prepare a measurement sample, and an impedance analyzer “ Using a "12608W type" (manufactured by Solartron Analytical Co., Ltd.), the dielectric constant (F / m) was measured by the electrode contact method in an environment of a temperature of 23 ° C. and a humidity of 50% RH under the condition of a frequency of 1 Hz to 1 MHz. , Converted to relative permittivity.

<Layer structure of intermediate transcript>
FIG. 1 is a conceptual cross-sectional view showing an example of the layer structure of the intermediate transfer member of the present invention.
The intermediate transfer body 1a of the present invention has at least a base material layer 2a.
The intermediate transfer body 1a may have a single-layer structure composed of only the base material layer 2a, but if necessary, layers such as an elastic layer 3a or a surface layer 4a are placed on the base material layer 2a in this order. It is also possible to have a configuration having the above.
The carbon nanotubes and the ferroelectric substance may be contained in the base material layer 2a or the elastic layer 3a, but it is particularly preferable to contain the carbon nanotubes and the ferroelectric substance in the base material layer 2a. The case where it is contained in the base material layer 2a will be described below.

The thickness of the intermediate transfer material can be appropriately determined depending on the purpose of use thereof and the like, but is preferably in the range of 50 to 100 μm. The thinner the thickness, the lower the voltage required for transfer, the more the discharge is suppressed, and the transfer efficiency is improved. Therefore, 100 μm or less is preferable. Further, if the thickness is 50 μm or more, the strength of the intermediate transfer material can be sufficiently maintained.

Electrical resistance of the intermediate transfer body (the volume resistivity) is preferably in the range of 10 ⁵ ~10 ¹¹ Ω · cm. The electric resistance value can be controlled by the content of the conductor described later.
As for the shape of the intermediate transfer body, the intermediate transfer body having an endless structure does not have a thickness change due to superposition, and an arbitrary part can be set as the rotation start position of the intermediate transfer body, and the control mechanism of the rotation start position can be omitted. It has advantages and is preferable.

<Base layer>
The base material layer in the present invention preferably contains carbon nanotubes and a ferroelectric substance. Further, the base material layer may contain a conductor other than carbon nanotubes.

In particular, the base material layer is preferably formed through the steps (A) to (C) described above, and contains carbon nanotubes and ferroelectric particles uniformly mixed and dispersed in the resin. That is, it is preferable that the base material layer is uniformly dispersed with the components constituting the base material layer to form a single layer.
Here, "uniformly dispersed" means the interface between a region in which only ferroelectric particles are filled and a region in which only carbon nanotubes are filled in a photograph of a substrate layer observed and photographed with a scanning electron microscope. Is invisible. However, there may be some ferroelectric particles or agglomerates of conductors as long as the effects of the present invention are not impaired.
As a specific confirmation method, in a photograph of the base material layer observed and photographed at a magnification of 3000 using a scanning electron microscope, whether or not it is a single layer is confirmed by whether or not an interface can be seen in the layer. The interface referred to here means a region in which dielectric particles are dispersed and a region in which carbon nanotubes are dispersed in the layer, and is a boundary between these regions. However, the agglomerate in which several particles are gathered is regarded as forming a single layer, unlike the above-mentioned region in which the ferroelectric particles or carbon nanotubes are dispersed.

Since the carbon nanotubes and the ferroelectric substance contained in the base material layer are as described above, the description thereof will be omitted here.
Further, the resin dispersed in the base material layer is also as described above.

(Other conductors)
The conductor that contains the carbon nanotubes and can be contained in addition to the carbon nanotubes is not particularly limited as long as it is a conductive substance. Specifically, as the conductor (conductive agent), known electronic conductive substances and ionic conductive substances can be used. For example, carbon black, graphite or graphene can be mentioned.

(Carbon black)
Examples of the carbon black include gas black, acetylene black, oil furnace black, thermal black, channel black, and Ketjen black. Effective methods for obtaining the desired conductivity with a smaller amount of mixing include Ketjen black, acetylene black and oil furnace black. Ketjen black is a contactive furnace type carbon black.

The average primary particle size of carbon black is preferably in the range of 10 to 50 nm. Within the range of the children, when the ferroelectric particles are coated with the conductor, it is easy to control the coverage of the ferroelectric particles by the conductor to an appropriate value.
The average primary particle size can be measured by the method of FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.) using a photon counting method.

(Graphite)
As the graphite, either a natural product or an artificial synthetic product can be used. It is difficult to unambiguously define the preferable particle size of graphite because the shape of graphite is scaly and the shape changes during the dispersion step during the production of the toner carrier, but it is difficult to unambiguously define it. The width (in the direction of the graphite fracture surface) is preferably 100 μm or less. As a measuring method, the sample is directly observed with a microscope and measured.

(Graphene)
The graphene is a sheet-like substance having a planar hexagonal lattice structure of carbon atoms. The graphene sheet is a flat graphene and is usually a single layer. Graphene sheets are artificial and are available as flaky powders. For example, it can be produced by a chemical vapor deposition (CVD) method.

The graphene sheet does not have to be completely single layer, and may partially include two or more layers. For this reason, graphene sheets have, for example, less than two layers. Further, the size is preferably less than 2 μm, and the thickness is preferably 2 nm or less. The graphene sheet laminate preferably has, for example, two or more layers, a size of 5 to 25 μm, and a thickness of 12 nm or less.

Commercially available products can be used for the graphene sheet and its laminate. The number, size and thickness of the graphene sheet and its laminate can be measured, for example, by a transmission electron microscope (TEM).

<Elastic layer>
The elastic layer in the present invention is a layer having desired conductivity and elasticity that can be formed on the outer peripheral surface of the base material layer, if necessary.
The elastic layer is made of a rubber material. The thickness of the elastic layer is preferably in the range of, for example, 50 to 400 μm.
Examples of rubber materials include resins having rubber elasticity such as urethane rubber, chloroprene rubber (CR) and acrylic nitrile rubber (NBR). The rubber material preferably contains chloroprene rubber or nitrile butadiene rubber from the viewpoint of controlling the electrical resistance of the intermediate transfer material.

<Surface layer>
If necessary, the surface layer (surface layer) is a layer that can be formed on the outer peripheral surface of the base material layer or on the outer peripheral surface of the elastic layer, and has an effect of improving transferability.
The surface layer is other than the metal oxide fine particles (A), the (meth) acrylate monomer (B) having a refractive index nD in the range of 1.6 to 1.8, and the (meth) acrylate monomer (B). It is preferably obtained by irradiating the coating film of the coating liquid for forming a surface layer containing the active energy ray-curable composition containing the polyfunctional (meth) acrylate (C) of the above with active energy rays and curing the coating liquid. .. This makes it possible to improve the durability of the intermediate transfer material.

[Electrophotograph image forming apparatus]
Next, an electrophotographic image forming apparatus including the intermediate transfer member of the present invention will be described.
The electrophotographic image forming apparatus of the present invention (hereinafter, also referred to as an image forming apparatus) is, for example, as shown in FIG. 2, 4 of yellow (Y), magenta (M), cyan (C), and black (K). A tandem image forming apparatus in which photoconductor drums 83Y, 83M, 83C, and 83K as photoconductors corresponding to colors are arranged in series in the traveling direction of the intermediate transfer body.

As shown in FIG. 3, the image forming apparatus 1 includes a control unit 10 composed of a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a memory such as a RAM (Random Access Memory) 13, and the like. A storage unit 20 composed of an HDD (Hard Disk Drive), an SSD (Solid State Drive), etc., a network I / F unit 30 composed of a NIC (Network Interface Card), a modem, etc., and a touch panel or the like. A display operation unit 40, an image reading unit 50 composed of an ADF (Auto Memory Feeder) and a scanner, an image processing unit 60 composed of a RIP (Raster Image Processor), a transport unit 70, and an image forming unit. The image forming unit 80 that processes the paper conveyed from the conveying unit 70, including the 80 and the like, includes the intermediate transfer body of the present embodiment.

As shown in FIG. 2, the transport unit 70 includes a paper feed device 71, a transport mechanism 72, a paper discharge device 73, and the like. The paper contained in the paper feeding device 71 is fed one by one from the uppermost portion, and is conveyed to the image forming unit 80 by a conveying mechanism 72 provided with a plurality of conveying rollers such as a resist roller. At this time, the resist portion on which the resist roller is arranged corrects the inclination of the fed paper and adjusts the transfer timing. Then, the paper on which the image is formed by the image forming unit 80 is discharged to the paper ejection tray outside the machine by the paper ejection device 73 provided with the paper ejection roller.

As shown in FIGS. 2 and 4, the image forming unit 80 includes an exposure apparatus 81 (81Y, 81M, 81C, 81K) and a developing apparatus 82 provided corresponding to different color components Y, M, C, and K. (82Y, 82M, 82C, 82K), Photoreceptor drum 83 (83Y, 83M, 83C, 83K), Charging device 84 (84Y, 84M, 84C, 84K), Cleaning device 85 (85Y, 85M, 85C, 85K), It is composed of a primary transfer roller 86 (86Y, 86M, 86C, 86K), an intermediate transfer unit 87, a fixing device 88, and the like. Each element will be outlined below. In the following description, symbols excluding Y, M, C, and K are used as necessary.

In the photoconductor drum 83 of each color component Y, M, C, K, an organic photoconductor layer (OPC) provided with an overcoat layer as a protective layer is formed on the outer peripheral surface of a cylindrical metal substrate made of an aluminum material. It is an image carrier. The photoconductor drum 83 is rotated counterclockwise in FIG. 2 by following the intermediate transfer body in a grounded state.

The charging device 84 for each of the color components Y, M, C, and K is a scorotron type, and is arranged close to the corresponding photoconductor drum 83 in a state in which the longitudinal direction thereof is along the rotation axis direction of the photoconductor drum 83. By corona discharge having the same polarity as the toner, a uniform potential is applied to the surface of the photoconductor drum 83.

The exposure apparatus 81 for each color component Y, M, C, and K scans in parallel with the rotation axis of the photoconductor drum 83 by, for example, a polygon mirror, and is uniformly charged on the surface of the corresponding photoconductor drum 83. An electrostatic latent image is formed by performing image exposure based on the image data.

The developing device 82 of each color component Y, M, C, K contains a two-component developer composed of a toner having a small particle size of the corresponding color component and a magnetic material, and the toner is applied to the surface of the photoconductor drum 83. The electrostatic latent image carried on the photoconductor drum 83 is visualized with toner.

The primary transfer roller 86 of each color component Y, M, C, K presses the intermediate transfer body 87a of the present invention against the photoconductor drum 83, and sequentially superimposes the toner images of each color formed on the corresponding photoconductor drum 83 in the middle. The primary transfer is performed on the transfer body 87a.

The cleaning device 85 for each of the color components Y, M, C, and K recovers the residual toner remaining on the corresponding photoconductor drum 83 after the primary transfer. Further, a lubricant application mechanism (not shown) is provided adjacent to the photoconductor drum 83 of the cleaning device 85 in the rotation direction, and the lubricant is applied to the photosensitive surface of the corresponding photoconductor drum 83. There is.

The intermediate transfer unit 87 includes an endless intermediate transfer body 87a to be transferred, a support roller 87b, a secondary transfer roller 87c, an intermediate transfer cleaning unit 87d, and the like, and the intermediate transfer body 87a is stretched on a plurality of support rollers 87b. It is constructed by being hung. When the intermediate transfer body 87a on which the toner images of each color are first transferred by the primary transfer rollers 86Y, 86M, 86C, and 86K is pressed against the paper by the secondary transfer roller 87c, the intermediate transfer body 87a and the secondary transfer roller 87c are brought into contact with each other. The toner image is secondarily transferred to the paper by the electric field acting on the toner based on the transfer voltage between them, and is sent to the fixing device 88. The intermediate transfer cleaning unit 87d has a belt cleaning blade that is slidably contacted with the surface of the intermediate transfer body 87a. The transfer residual toner remaining on the surface of the intermediate transfer body 87a after the secondary transfer is scraped off and removed by the belt cleaning blade.

The fixing device 88 includes a heating roller 88a and a fixing roller 88b as heat sources, a fixing belt 88c and a pressure roller 88d hung on the fixing roller 88b, and the pressure roller 88d is pressed against the fixing roller 88b via the fixing belt 88c. The pressure contact portion constitutes the nip portion. Then, the fixing belt 88c heated by the heating roller 88a and each roller heat and pressurize the paper passing through the nip portion to fix the unfixed toner image formed on the paper.

Then, the paper on which the toner image is fixed by the fixing device 88 is discharged to the paper ejection tray outside the machine by the paper ejection device 73 provided with the paper ejection roller.

Note that FIGS. 2 and 4 are examples of the image forming apparatus 1 of the present invention, and the structure and configuration thereof can be appropriately changed as long as the intermediate transfer body 87a of the present invention can be used.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples, the operation was performed at room temperature (25 ° C.) unless otherwise specified. Unless otherwise specified, "%" and "parts" mean "mass%" and "parts by mass", respectively.

[Synthesis of barium titanate particles]
With reference to paragraphs 0033 to 0044 of Patent No. 6368246, a titanium hydroxide-containing aqueous solution was used as the titanium salt aqueous solution, a barium nitrate aqueous solution was used as the barium salt aqueous solution, and a sodium hydroxide aqueous solution was used as the alkaline aqueous solution. The raw materials were prepared so that the amount of Ba was 10 mol and the amount of alkali was 60 mol [neutralization degree = alkali amount / (4 × Ti amount + 2 × Ba amount) = 1.0].
Next, in the raw material tank, an aqueous solution of sodium hydroxide is added to an aqueous solution containing titanium hydroxide at room temperature and in the air, and then an aqueous solution of barium nitrate is added to form a reaction precursor, amorphous barium and titanium hydroxide. An aqueous solution containing the substance was prepared. The pH value of the reaction precursor after preparation was 13.2. The prepared reaction precursor was hydrothermally reacted with a continuous hydrothermal reactor at a temperature of 400 ° C., a pressure of 25 MPa, and a residence time of 0.4 minutes, and then filtered, washed with water and dried to obtain barium titanate particles. ..
The average primary particle size of the obtained barium titanate particles was 100 nm. The average primary particle size was measured by the method for measuring the average primary particle size of the ferroelectric particles described above.

[Synthesis of strontium titanate particles]
After deironing and bleaching the metatitanic acid obtained by the sulfuric acid method, sodium hydroxide aqueous solution is added to adjust the pH to 8.8, desulfurization is performed, and then neutralized to pH 5.7 with hydrochloric acid, filtered and washed with water. rice field. Water was added to the washed cake to make _{a slurry of 1.85 mol / L as TiO 2} , and then hydrochloric acid was added to adjust the pH to 1.0 for degluing treatment. 0.63 mol of this metatitanic acid was _{sampled in terms of TiO 2} and charged into a 3 L reaction vessel.
Next, 0.71 mol of an aqueous solution of strontium chloride was added so that the SrO / TiO _{2 mol ratio was 1.14, and then the TiO 2} concentration was adjusted to 0.28 mol / L. Next, after heating to 90 ° C. while stirring and mixing, 290 mL of a 5N sodium hydroxide aqueous solution was added over 16 hours, and then stirring was continued at 95 ° C. for 1 hour to complete the reaction. The reaction slurry was cooled to 50 ° C., hydrochloric acid was added until the pH reached 5.0, and stirring was continued for 1 hour. The obtained precipitate was decanted and washed, filtered, and dried in the air at 120 ° C. for 8 hours to obtain strontium titanate particles.
The average primary particle size of the obtained strontium titanate particles was 200 nm. The average primary particle size was measured by the method for measuring the average primary particle size of the ferroelectric particles described above.

[Manufacturing of intermediate transcript 1]
<Step (A)>
Using a bead mill disperser, carbon nanotubes (CNTs40 (N), manufactured by SUSN) (average diameter: 10 nm, average length: 40 μm) were dispersed in a solvent (N-methyl-2-pyrrolidone). At this time, the particle size distribution was measured by a dynamic scattering method as a dispersion index, and the carbon nanotubes were dispersed until the fluctuation rate of the average particle size was within 5% to obtain a solvent dispersion liquid 1-A1.
Further, the resin of the polyimide varnish "Yupia-AT (U-varnish-A)" (manufactured by Ube Industries, Ltd.) was dissolved in a solvent (N-methyl-2-pyrrolidone) to obtain a resin solution 1-A2.
Then, the solvent dispersion 1-A1 and the resin solution 1-A2 are mixed using a bead mill disperser so that the carbon nanotube concentration becomes 0.45% by mass to obtain a carbon nanotube dispersion 1-A. rice field.

<Process (B)>
The barium titanate particles synthesized above were dispersed in a solvent (N-methyl-2-pyrrolidone) using a bead mill disperser. At this time, the particle size distribution was measured by a dynamic scattering method as a dispersion index, and the particles were dispersed until the fluctuation rate of the average particle size of the barium titanate particles was within 5% to obtain a solvent dispersion liquid 1-B1.
Further, the resin of the polyimide varnish "Yupia-AT (U-varnish-A)" (manufactured by Ube Industries, Ltd.) was dissolved in a solvent (N-methyl-2-pyrrolidone) to obtain a resin solution 1-B2.
Then, the solvent dispersion 1-B1 and the resin solution 1-B2 were mixed using a bead mill disperser to obtain a ferroelectric dispersion 1-B.

<Process (C)>
The carbon nanotube dispersion liquid 1-A having a carbon nanotube concentration of 0.45% by mass obtained in the step (A) and the ferroelectric dispersion liquid 1-B obtained in the step (B) are agitated. The coating liquid 1 for forming the base material layer was prepared by mixing using a mold mixing mixer. At this time, the carbon nanotube dispersion 1-A and the ferroelectric dispersion 1-B are mixed so as to have 0.50% by volume of carbon nanotubes and 15% by volume of barium titanate for forming the base material layer. Coating liquid 1 was prepared.
Next, while rotating the stainless steel cylindrical mold about the cylindrical shaft and moving the dispense nozzle in the axial direction, the coating liquid 1 for forming the base material layer is discharged from the nozzle to form the mold. It was spirally applied on the outer peripheral surface to form a coating film in which they were connected.
Next, most of the solvent was volatilized by heating the cylindrical mold at 130 ° C. for 1 hour while rotating the mold, and then heating at 350 ° C. for 1 hour to form an endless belt-shaped base material layer. .. The thickness of the base material layer formed by the above method was 65 μm. Then, SSG HB21B (manufactured by Nittobo Medical Co., Ltd.) was applied onto this base material layer by a dip coating method to form a surface layer, and an intermediate transfer body 1 was produced.

[Manufacturing of intermediate transcript 2]
In the step (A) in the production of the intermediate transfer material 1, carbon nanotubes (CNTs40 (N), manufactured by SUSN) (average diameter: 10 nm, average length: 40 μm) and a solvent (N) were used using a bead mill disperser. -Methyl-2-pyrrolidone) and the resin of the polyimide varnish "Yupia-AT (U-varnish-A)" (manufactured by Ube Industries, Ltd.) are mixed at once, and the carbon nanotubes having a carbon nanotube concentration of 0.42% by mass are mixed. Dispersion 2-A was obtained.
Further, in the step (C), the carbon nanotube dispersion liquid 2-A and the intermediate transfer body 1 are produced in the same manner as in the step (B) so that the carbon nanotubes are 0.60% by volume and the barium titanate is 15% by volume. The intermediate transfer material 2 was produced in the same manner except that the coating liquid 2 for forming the base material layer was prepared by mixing the ferroelectric dispersion liquid prepared in the above.

[Manufacturing of intermediate transcript 3]
In the step (A) in the production of the intermediate transfer material 1, a carbon nanotube dispersion liquid 3-A was obtained in the same manner except that the carbon nanotube concentration was adjusted to 0.48% by mass.
Further, in the step (B), the barium titanate particles synthesized above using the bead mill disperser, the solvent (N-methyl-2-pyrrolidone), and the polyimide varnish "Yupia-AT (U-varnish-A)" are used. ) ”(Manufactured by Ube Industries, Ltd.) was mixed at once to obtain a ferroelectric dispersion liquid 3-B.
Further, in the step (C), the carbon nanotube dispersion liquid 3-A and the ferroelectric dispersion liquid 3-B are mixed so as to have 0.65% by volume of carbon nanotubes and 15% by volume of barium titanate. The intermediate transfer material 3 was produced in the same manner except that the coating liquid 3 for forming the base material layer was prepared.

[Manufacturing of intermediate transcripts 4 to 11]
The average diameter and average length of carbon nanotubes used in the production of the intermediate transfer material 1, the concentration of carbon nanotubes in the carbon nanotube dispersion liquid prepared in the step (A), the content of strong dielectrics (% by volume), Intermediate transfer bodies 4 to 11 were produced in the same manner, except that the content of carbon nanotubes (% by volume), the type of strong dielectric, and the presence or absence of a surface layer were changed as shown in Table I below.

[Manufacturing of intermediate transcript 12]
In the step (A) in the production of the intermediate transfer material 1, carbon nanotubes (CNTs40 (N), manufactured by SUSN) (average diameter: 10 nm, average length: 40 μm) were used as a solvent (N-) using a bead mill disperser. A carbon nanotube dispersion liquid 12-A containing no resin was prepared by dispersing it in methyl-2-pyrrolidone).
Then, in the step (C), the carbon nanotube dispersion liquid 12-A and the ferroelectric dispersion liquid prepared in the same manner as in the step (B) in the production of the intermediate transfer material 1 are mixed to form a base material layer. The intermediate transfer material 12 was produced in the same manner except that the coating liquid 12 was prepared.

[Manufacturing of intermediate transcript 13]
In the step (B) in the production of the intermediate transfer material 1, the barium titanate particles synthesized above are dispersed in a solvent (N-methyl-2-pyrrolidone) using a bead mill disperser and do not contain a resin. , The ferroelectric dispersion liquid 13-B was prepared.
Then, in the step (C), the carbon nanotube dispersion liquid prepared in the same manner as in the step (A) in the production of the intermediate transfer material 1 and the ferroelectric dispersion liquid 13-B are mixed to form a base material layer. The intermediate transfer material 13 was produced in the same manner except that the coating liquid 13 was prepared.

For each intermediate transfer material produced above, the dispersion V and the relative permittivity, which are indicators of the logarithmic variation of the surface resistivity at a plurality of in-plane locations, were calculated by the following methods, and the results are shown in Table I below. ..

<Dispersion V>
The surface resistivity of the intermediate transfer material is measured by allowing the intermediate transfer material to stand in an environment of 23 ° C. and 55% relative humidity for 24 hours, and then measuring the surface resistivity of a plurality of places on the surface of the intermediate transfer material. Using a device (manufactured by Mitsubishi Chemical Analytech Co., Ltd., High Restor UP, MCP-HT450), measurements were taken at 10 points by the 4-terminal method. The squared value of the difference between each of the 10 measured data and the average value of all the data was summed, and the value divided by the number of data was defined as the variance V.

<Relative permittivity>
The dielectric constant was measured for the intermediate transfer material. Specifically, as shown in FIG. 5, a thin film electrode 201 having a resistance of 1 digit Ω is formed on both sides of the intermediate transfer body 87a by sputtering or the like, and cut out with a mold of 10 mmφ to prepare a measurement sample, and an impedance analyzer “ Using a "12608W type" (manufactured by Solartron Analytical Co., Ltd.), the dielectric constant (F / m) was measured by the electrode contact method in an environment of a temperature of 23 ° C. and a humidity of 50% RH under the condition of a frequency of 1 Hz to 1 MHz. , Converted to relative permittivity.

[evaluation]
Transfer unevenness, transferability and mechanical strength were evaluated for each intermediate transfer product produced above.
The intermediate transfer material was mounted on an image forming apparatus "KONICA MINOLTA bizhub PRESS C11000" (manufactured by Konica Minolta), and the following evaluation test was performed using embossed paper (Rezac, 302 g paper) as an image support.
After printing one million images with a printing rate of 20%, an operation was performed to output 1000 blue (mixed colors of cyan and magenta) halftone images on the entire surface of the embossed paper, and the obtained visible images were visually displayed. The transfer unevenness was evaluated, and the magenta reflection density in the image was measured to evaluate the transferability (the evaluation criteria will be described later). Furthermore, a bending test (mechanical strength evaluation) of the intermediate transfer material after printing one million sheets was carried out.

<Transfer unevenness>
The evaluation criteria for transfer unevenness are as follows.
⊚: No transfer unevenness is observed.
◯: There is slight transfer unevenness in the recesses of the embossed paper, but it is recognized that there is no problem in practical use.
Δ: There is slight transfer unevenness on the convex portion of the embossed paper, but it is recognized that there is no problem in practical use.
X: It is recognized that there is a problem in practical use due to uneven transfer on the entire paper.

<Transportability>
The evaluation criteria for transferability are as follows.
The cyan reflection density was measured at three points (three points) in the halftone image. The average value of the three points was evaluated according to the following criteria.
⊚: Reflection density average value 1.40 or more ○: Reflection density average value 1.20 or more and less than 1.40 Δ: Reflection density average value 1.0 or more and less than 1.20 ×: Reflection density average value less than 1.0

<Mechanical strength>
After outputting the above blue halftone image, a bending test (MIT test) was performed in accordance with JIS P 8115. The number of round trips to break was measured and evaluated according to the following evaluation criteria. If the number of round trips to break is 6000 or more, it is estimated that there is almost no possibility of cracking during use, and if it is less than 1000, there is a high risk of the belt breaking during printing and the product is rejected.
⊚: 6000 times or more 〇: 4000 times or more, less than 6000 times Δ: 1000 times or more and less than 4000 times ×: less than 1000 times

As shown in the above results, it is recognized that the intermediate transfer product of the present invention is superior to the intermediate transfer material of the comparative example in terms of transfer unevenness, transferability and mechanical strength.

1a Intermediate transfer member 2a Base material layer 3a Elastic layer 4a Surface layer 1 Image forming apparatus 10 Control unit 11 CPU
12 ROM
13 RAM
20 Storage unit 30 Network I / F unit 40 Display operation unit 50 Image reading unit 60 Image processing unit 70 Transport unit 71 Feeding device 72 Transport mechanism 73 Paper ejection device 80 Image forming unit 81, 81Y, 81M, 81C, 81K Exposure device 82, 82Y, 82M, 82C, 82K Developer 83, 83Y, 83M, 83C, 83K Photoreceptor drum 84, 84Y, 84M, 84C, 84K Charging device 85, 85Y, 85M, 85C, 85K Cleaning device 86, 86Y, 86M , 86C, 86K Primary transfer roller 87 Intermediate transfer unit 87a Intermediate transfer body 87b Support roller 87c Secondary transfer roller 87d Intermediate transfer cleaning unit 88 Fixing device 88a Heating roller 88b Fixing roller 88c Fixing belt 88d Pressurizing roller 201 Thin film electrode

Claims (12)

A method for producing an intermediate transfer material containing carbon nanotubes and a ferroelectric substance.
The step (A) of mixing the carbon nanotubes, the resin, and the solvent to obtain a carbon nanotube dispersion liquid,
The step (B) of mixing the ferroelectric substance, the resin, and the solvent to obtain a ferroelectric dispersion liquid.
A step (C) of mixing the carbon nanotube dispersion liquid obtained in the step (A) with the ferroelectric dispersion liquid obtained in the step (B), and forming and drying the obtained coating liquid. A method for producing an intermediate transfer material, which comprises. In the step (A), the solvent dispersion liquid obtained by dispersing the carbon nanotubes in a solvent and the resin solution obtained by dissolving the resin in a solvent are mixed to form the carbon nanotube dispersion liquid. The method for producing an intermediate transcript according to claim 1, wherein the intermediate transfer product is obtained. In the step (B), the solvent dispersion liquid obtained by dispersing the ferroelectric substance in a solvent and the resin solution obtained by dissolving the resin in a solvent are mixed to obtain the ferroelectric substance. The method for producing an intermediate transcript according to claim 1 or 2, wherein a dispersion is obtained. Any of claims 1 to 3, wherein the carbon nanotube concentration of the carbon nanotube dispersion liquid obtained in the step (A) is in the range of 0.16 to 0.60% by mass. The method for producing an intermediate transcript according to claim 1. An intermediate transfer material containing carbon nanotubes and a ferroelectric substance.
An intermediate transfer product characterized in that the dispersion V, which is an index of logarithmic variation of the surface resistivity at a plurality of in-plane locations, is 0.015 or less. The intermediate transfer member according to claim 5, wherein the relative permittivity of the intermediate transfer body at a frequency of 1 MHz is in the range of 10 to 60. The intermediate transfer product according to claim 5 or 6, wherein the content of the ferroelectric substance is in the range of 5 to 25% by volume. The intermediate transfer product according to any one of claims 5 to 7, wherein the content of the carbon nanotubes is in the range of 0.3 to 2.0% by volume. The intermediate transfer material according to any one of claims 5 to 8, wherein the ferroelectric substance contains barium titanate or strontium titanate. The intermediate transfer product according to any one of claims 5 to 9, wherein the average diameter of the carbon nanotubes is in the range of 5 to 50 nm. The intermediate transfer product according to any one of claims 5 to 10, wherein the average length of the carbon nanotubes is in the range of 0.1 to 50 μm. The intermediate transfer product according to any one of claims 5 to 11, wherein a surface layer is provided on the layer containing the carbon nanotubes and the ferroelectric substance.

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