JPH0973237A - Intermediate transfer body and image forming method using the intermediate transfer body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intermediate transfer body having superior transferring ability, excellent in durability and capable of giving a high quality image with satisfactory reproducibility by forming the transfer layer of an intermediate transfer body with a material obtd. by vulcanizing a compsn. contg. acrylonitrile- butadiene rubber and a vulcanizing agent. SOLUTION: In an intermediate transfer body with a transfer layer and an elastic layer disposed in this order from the outer surface side, the transfer layer is formed with a material obtd. by vulcanizing a compsn. contg. at least acrylonitrile-butadiene rubber and a vulcanizing agent. The ratio of acrylonitrile to butadiene in the acrylonitrile-butadiene rubber is not especially limited but the acrylonitrile content is preferably <=25wt.%. A vulcanization accelerator such as a thiuram compd., a sulfenamido compd. or fatty acid may be used as the vulcanizing agent besides sulfur. The thickness of the transfer layer is preferably 0.2-10μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention develops an electrostatic latent image on an electrostatic latent image carrier with a liquid toner, and electrostatically transfers the visualized image to the intermediate transfer body. The present invention relates to an intermediate transfer member used in an image forming method for re-transferring the developed image on the intermediate transfer member onto a transfer material, and is used, for example, in a copying machine or a laser beam printer. The present invention relates to an intermediate transfer member used in an image forming method.

[0002]

2. Description of the Related Art The following intermediate transfer members are used in the above-described image forming method.

For example, Japanese Patent Application Laid-Open No. 3-154085 (Prior Art 1) discloses an intermediate transfer member having an elastic layer composed of two dielectric layers having a smooth surface and a thin dielectric layer and a conductor layer supporting the dielectric. ing. However, as for the material of the intermediate transfer member, there is only a description that a material such as a silicon coat or a fluorine coat may be used.

Further, JP-A-3-243973 (Prior Art 2) discloses an intermediate transfer member having an elastic layer having a smooth surface and having a property of absorbing a solvent in a liquid toner. This elastic layer is composed of a dielectric layer and a conductor layer,
Specifically, there is mentioned an intermediate transfer medium in which a conductive silicone rubber is coated with an insulating silicone rubber, but there is no description about the silicone used.

Further, Japanese Patent Laid-Open No. 1-273075 (conventional example 3) discloses an intermediate transfer member having a dielectric layer formed on a conductive base material. Specifically, the intermediate transfer member is formed by providing a dielectric layer made of a polytetrafluoroethylene layer on a conductive base material made of urethane rubber.

[0006]

The requirements for the intermediate transfer member used in the above-described image forming method include the following items.

(1) The visible image is efficiently transferred to the intermediate transfer member.

(2) The visible image on the intermediate transfer member is efficiently retransferred onto the transfer material.

(3) No image deterioration occurs during transfer.

(4) The intermediate transfer member has durability.

However, none of the above-mentioned conventional examples 1 to 3 satisfy all of the above requirements (1) to (4).

For example, as in the case of the conventional example 1, merely using a material such as a silicon coat or a fluorine coat cannot provide sufficient durability. Further, in Conventional Example 2, since the conductive silicone rubber is used for the elastic layer, there is a problem that the elastic layer swells with the solvent used for the liquid toner and the visible image on the intermediate transfer member is disturbed. In Conventional Example 3, since polyurethane rubber is used for the elastic layer, the heat resistance of the polyurethane rubber is insufficient when the method of retransfer to the transfer material by a heater is used. There was a problem.

In order to solve such a problem, the present inventors have proposed an intermediate transfer member in Japanese Patent Application No. 6-5030 in which an adhesive layer is formed on a conductive base material and a dielectric layer is formed thereon. Proposed. This intermediate transfer member is specifically formed by providing an adhesive layer on a conductive base material made of fluororubber and then providing a dielectric layer made of a silicone rubber layer thereon. However, there is only a description that silicone rubber may be used as the material of the dielectric layer.

The present invention was made in view of the above-mentioned drawbacks, and an object of the present invention is to efficiently transfer a visible image to an intermediate transfer member, and to transfer the visible image on the intermediate transfer member to a transfer target. An object of the present invention is to provide an intermediate transfer member that satisfies the four requirements of being efficiently retransferred onto a material, no deterioration of an image during transfer, and durability of the intermediate transfer member.

[0015]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
The electrostatic latent image on the electrostatic latent image carrier is developed with liquid toner, the developed image visualized by this development is electrostatically transferred to the intermediate transfer body, and then the developed image on the intermediate transfer body. Is an intermediate transfer member used in an image forming method for retransferring
In an intermediate transfer member in which at least a transfer layer and an elastic layer are provided in this order from the outer surface side, the transfer layer is obtained by vulcanizing a composition containing at least acrylonitrile butadiene rubber and a vulcanizing agent. It is achieved by the intermediate transfer member.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

In the intermediate transfer member of the present invention, the transfer layer of the intermediate transfer member is at least acrylonitrile butadiene rubber,
And a vulcanizing composition containing a vulcanizing agent.

The acrylonitrile butadiene rubber is not particularly limited as long as it is a commonly used one, but the acrylonitrile ratio is preferably 25% by weight or less. .

Examples of the vulcanizing agent include, in addition to sulfur, vulcanization accelerators such as thiuram compounds, sulfenamide compounds, fatty acids and phenol-formaldehyde resins, but are not limited thereto. If the acrylonitrile butadiene rubber is not vulcanized, good durability as an intermediate transfer member cannot be obtained.

In the transfer layer, paraffinic oil, hydrous silicic acid, carbon black,
You may add zinc oxide etc.

The thickness of the transfer layer is 0.2 μm or more and 1
It is preferably 0 μm or less, and more preferably 0.5 μm or more and 5 μm or less. If it is less than 0.2 μm, the retransfer from the intermediate transfer member to the transfer target is not sufficient, and if it exceeds 10 μm, four colors are superposed on the intermediate member and the paper is transferred once in a single transfer. In the process of retransfer, there is a problem in color superimposition.

The intermediate transfer member of the present invention has a transfer layer provided on the surface thereof, and an elastic layer is provided below the transfer layer with or without an adhesive layer. The structure may be in the form of a belt in which at least an elastic layer and a transfer layer are sequentially laminated on a substrate such as aluminum, iron, or a plastic film, or at least an elastic layer is formed on a drum such as aluminum or iron. A drum-shaped form in which the transfer layer and the transfer layer are sequentially laminated may be used. Further, an adhesive layer may be provided between the elastic layer and the substrate or between the elastic layer and the drum.

As the elastic layer, for example, fluororubber,
Examples of the conductive elastic layer include those obtained by making silicone rubber, acrylic rubber, neoprene rubber, urethane rubber and the like conductive, and the conductive fluororubber layer is preferable. That is, when a heat roller containing a heat source is used when transferring from an intermediate transfer member to a transfer agent, a heat resistant one is required as a conductive elastic layer, and further, a hydrocarbon used in a liquid toner. This is because it is required not to swell in the system solvent.

Specific examples of the conductive fluororubber layer used in the intermediate transfer member of the present invention include vinylidene fluoride-hexafluoropropene-based, vinylidene fluoride-chlorotrifluoroethylene-based and vinylidene fluoride-penta. Fluoropropene-based, tetrafluoroethylene-propylene-based, fluorine-containing silicon-based, fluorine-containing nitroso-based, fluorine-containing triazine-based, and fluorine-containing phosphazene-based materials in which carbon black is dispersed in order to impart conductivity are used.

As the carbon black dispersed in the fluororubber, any known carbon black can be used, but it is preferable to use Ketjen black in order to impart good conductivity. The dispersion amount of carbon black is preferably 2% by weight or more and 10% by weight or less. If it is less than 2% by weight, the conductivity becomes insufficient, and 10
When it exceeds the weight%, there is a problem that the smoothness of the surface of the conductive fluororubber layer is lost.

The elastic layer has a volume resistivity of 10
⁸ (Ω · cm) or less is preferable, and 10 ⁵ (Ω · c)
m) The following are more preferable. Volume resistivity is 10 ⁸
If the value exceeds (Ω · cm), an image is formed by superimposing multiple colors on the intermediate transfer member, and the visible image on the intermediate transfer member is retransferred onto the transfer agent in one transfer. In such a case, there is a problem that the transferability is deteriorated when the visible image on the photoconductor is to be transferred onto the already transferred visible image on the intermediate transfer member.

The hardness of the elastic layer is Shore A2.
It is preferably 0 or more and 50 or less. When the Shore A is less than 20, there is a problem that the image is disturbed when a visible image is transferred from the electrostatic latent image carrier (photoconductor) to the intermediate transfer member. Further, when the Shore A50 is exceeded, when transferring from an intermediate transfer member to a transfer target, a problem such as a poor transfer rate tends to occur when the transfer target is a material such as paper having a poor surface smoothness.

The thickness of the elastic layer is 50 μm or more and 50
It is preferably 00 μm or less. More preferably 5
It is not less than 00 μm and not more than 3000 μm. When it exceeds 5000 μm, there is a problem that the image is disturbed when a visible image is transferred from the electrostatic latent image carrier (photoreceptor) to the intermediate transfer member. On the other hand, when it is less than 50 μm, the effect of improving the fixing property between the intermediate transfer member and the electrostatic latent image carrier is not recognized.
Further, when transferring from an intermediate transfer member to a transfer agent, a problem such as a poor transfer rate is likely to occur when the transfer target is a material such as paper having a poor surface smoothness.

When a conductive fluororubber layer is used as the elastic layer, it is preferable to provide an adhesive layer between the elastic layer and the acrylonitrile butadiene rubber layer. When the adhesive layer is not provided, the durability is not good because the conductive fluororubber layer and the acrylonitrile butadiene rubber layer are not sufficiently adhered.

As the adhesive layer, a primer or the like usually used for adhering acrylonitrile-butadiene rubber can be used, but it is preferable to provide a polyolefin-based primer and a phenol-based primer in this order from the outer surface side.

These primers may be, for example, methanol, ethanol, propanol, butanol, if necessary.
It may be diluted with a solvent such as toluene, hexane, benzene, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, methylene chloride, chloroform or carbon tetrachloride.

The thickness of the adhesive layer is 0.2 μm or more and 5
μm or less is preferable. If it is less than 0.2 μm, the adhesiveness is insufficient, and if it exceeds 5 μm, cohesive failure occurs inside the adhesive layer, resulting in poor adhesiveness. Further, the thickness of the dielectric layer (transfer layer + adhesive layer) becomes thicker, resulting in poor color superposition.

Next, an image forming method using the intermediate transfer member of the present invention will be described.

The intermediate transfer member of the present invention develops the electrostatic latent image on the electrostatic latent image carrier with a liquid toner, and electrostatically develops the visualized image on the intermediate transfer member. It is used in an image forming method in which after the transfer, the visible image on the intermediate transfer member is retransferred onto the transfer target material. This image forming method is used, for example, in a copying machine or a laser beam printer.

The intermediate transfer member of the present invention is, in particular, an image in which the material to be transferred is brought into close contact with the intermediate transfer member by a pressure roller when the image on the intermediate transfer member is retransferred to the material to be transferred. It is preferably used in the forming method. Pressure used here
As the roller, a metal roller or a roller in which the surface of the metal roller is covered with a rubber having high heat resistance such as silicone rubber or fluororubber in order to enhance the adhesion with the intermediate transfer member. And so on. In particular, the pressure roller is preferably used in an image forming method in which the pressure roller is a heat roller including a heat source. Such a pressure roller has a cylindrical structure and includes a heat source such as a ceramic heater or a halogen lamp.

Further, the image forming method is a color image forming method, and the color is formed by superposing multiple colors on the intermediate transfer member.
The image forming method is preferably an image forming method in which an image is formed, and the visible image on the intermediate transfer member is retransferred onto the transfer target material by one transfer.

The material to be transferred referred to in the present invention is as follows.
Any kind of paper, plastic film, metal, cloth, board, etc. can be used as long as it can be printed normally.

The thickness of the transfer layer can be measured by a general method such as a gravimetric method or an optical method.

[0039]

EXAMPLES Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.

(Example 1) 1,000 μm vulcanization molding was performed by adding 5 wt% of Ketjen black to Afras # 150 (Asahi Glass Co., Ltd.), which is a tetrafluoroethylene-propylene rubber system, on a 200 μm aluminum plate. A fluororubber layer of Shore D20 is provided, and a layer made of a phenolic primer is coated thereon with a thickness of 1 μm by bar coating.
A layer made of a polyolefin-based primer was further provided thereon by bar coating to have a thickness of 1 μm, and 10 g of compounded acrylonitrile butadiene rubber was dissolved in n-heptane as a transfer layer on the layer, and the mixture was further mixed for 2 hours. The mixture diluted to a concentration of 6% by weight with n-heptane was applied by bar coating to 2 μm, and 1
It heated at 50 degreeC for 2 hours, and formed the intermediate transfer body.

The composition of the compounded acrylonitrile butadiene rubber includes rubber, paraffin oil, hydrous silicic acid, zinc oxide,
Sulfur, a sulfenamide-based vulcanizing agent, and a fatty acid.

As a liquid developer, a pigment, an ethylene-vinyl acetate copolymer resin, cobalt naphthenate, and Isopar-H are wet-dispersed with a ball mill in a ratio of 3: 3: 1: 93, and a photoreceptor is used. After developing on the Se drum, an image was sequentially formed in the order of yellow, red, indigo, and black on the intermediate transfer body stuck on the drum, and a full-color image was formed on the intermediate transfer body. Apply 20kg of linear pressure to the full-color image,
Further, when the transfer was performed under the condition that the temperature of the pressure roller was 150 ° C., a good printed matter could be obtained from the intermediate transfer member to the paper at a transfer rate of almost 100%. Further, 2,000 sheets were continuously printed, but a printed matter equivalent to the first sheet was obtained, and the intermediate transfer member could be used without any defect.

(Comparative Example 1) On a 200 μm aluminum plate, 1,000 μm vulcanization molding was performed by adding 5 wt% of Ketjen Black to Afras # 150 (Asahi Glass Co., Ltd.) which is a tetrafluoroethylene-propylene rubber system. A fluororubber layer of Shore D20 is provided, and a layer made of a phenolic primer is coated thereon with a thickness of 1 μm by bar coating.
A layer made of a polyolefin-based primer is further provided thereon by bar coating to have a thickness of 1 μm, and an acrylonitrile butadiene rubber PNR-1H (Nippon Synthetic Rubber Co., Ltd .: unvulcanized) is further provided thereon as a transfer layer. ) 10 g was dissolved in methyl ethyl ketone and mixed for 2 hours, and then the concentration was adjusted to 6 with methyl ethyl ketone.
The mixture diluted by weight to 2 by bar coating
μm was applied to form an intermediate transfer member.

When a printing test was conducted in the same manner as in Example 1, good printed matter was obtained up to the 100th sheet.
Defects began to appear on the printed matter from the time when 0 sheets were passed. When the intermediate transfer member was removed and examined, it was found that the acrylonitrile butadiene rubber layer was peeled from the adhesive layer.

[0045]

As described above, since the intermediate transfer member of the present invention has excellent transferability and excellent durability, the image forming method using this intermediate transfer member produces a high quality image. It can be obtained with good reproducibility.

Claims (7)

[Claims] 1. An electrostatic latent image on an electrostatic latent image carrier is developed with liquid toner, the developed image visualized by the development is electrostatically transferred to an intermediate transfer body, and then the intermediate transfer is performed. An intermediate transfer member used in an image forming method for retransferring a visible image on a body onto a transfer target, wherein at least a transfer layer and an elastic layer are provided in this order from the outer surface side, The transfer layer is at least acrylonitrile butadiene rubber,
And an intermediate transfer member obtained by vulcanizing a composition containing a vulcanizing agent. 2. The intermediate transfer member according to claim 1, wherein the elastic layer is a conductive fluororubber layer. 3. The intermediate transfer member according to claim 1, which has at least one adhesive layer between the elastic layer and the silicone rubber layer. 4. The intermediate transfer member according to claim 1, wherein the adhesive layer comprises a layer containing a phenolic primer and a layer containing a polyolefinic primer. 5. The intermediate transfer member according to claim 3, wherein the thickness of the adhesive layer is 0.2 μm or more and 5 μm or less. 6. The transfer layer has a thickness of 0.2 μm or more and 10 μm.
The intermediate transfer member according to claim 1, wherein: 7. An electrostatic latent image on an electrostatic latent image carrier is developed with a liquid toner, the developed image visualized by this development is electrostatically transferred to an intermediate transfer body, and then the intermediate transfer is carried out. An image forming method for retransferring a visible image on a body to a transfer material, wherein the intermediate transfer body according to any one of claims 1 to 6 is used as the intermediate transfer body.