JP2006047609A - Transfer belt for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the multilayered transfer belt for an image forming apparatus consisting of a base layer, an intermediate layer, and a surface layer, having a large surface resistance, excellent for releasing the toner, and also excellent against contamination. <P>SOLUTION: This transfer belt for an image forming device has an intermediate layer made of an elastomer, especially urethane, acrylonitrile-budadiene rubber, ethylene rubber, silicone rubber, polyamide, or made of two or more of them, and a surface layer made of fluorine containing polymer on the base layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image used for transferring a toner image on a photosensitive drum onto a transfer material (paper) in an image forming apparatus using an electrophotographic method, particularly a color image forming apparatus such as a color copying machine or a color laser printer. The present invention relates to a transfer belt for a forming apparatus.

  As a method of transferring an image in a color image forming apparatus such as a color copying machine or a color laser printer, there is a method of transferring a toner image formed on a photosensitive drum onto a transfer material (paper) using a transfer belt for the image forming apparatus. , Becoming standard.

  FIG. 7 is an explanatory diagram showing an outline of an intermediate transfer system which is one of the systems. As shown in FIG. 7, a toner image is formed on the photosensitive drum 3 by the toner 1 and the developing roller 2. Since this method is a quadruple tandem method, four color toners, a developing roller and a photosensitive drum corresponding to each toner are provided. The toner image formed on the photosensitive drum 3 is transferred to the image forming apparatus transfer belt 5 by the primary transfer roller 4, the photosensitive drum 3, and the image forming apparatus transfer belt 5. The formed color image is transferred to a transfer material (paper) 7 by a secondary transfer roller 6, an image forming apparatus transfer belt 5, and a transfer material (paper) 7, and a fixing roller (not shown). ). The basic principle is the same for the multiple transfer method.

  The transfer belt for an image forming apparatus used in these methods has a large resistivity (surface resistivity) in the circumferential direction of the belt, and a resistivity in the thickness direction (volume resistivity) smaller than the surface resistivity, In addition, the resistivity does not vary depending on the position on the belt surface, use environment, voltage, etc., the belt has a high tensile elastic modulus in the circumferential direction, the surface is smooth, the contact angle is large, and the toner is transferred from the belt ( Characteristics such as being easily transferred to paper (excellent toner releasing property), not chemically contaminating the photosensitive drum or toner (excellent non-contaminating property), and flame retardancy are desired. .

  Since it is difficult to satisfy a large number of these characteristics with a single-layer image forming apparatus transfer belt, a multi-layer image forming apparatus transfer belt has been proposed. For example, Japanese Patent Application Laid-Open No. 2002-287531 Has a low resistance thermoplastic elastomer base layer and a high resistance thermoplastic elastomer surface layer, and the base layer and the surface layer are formed by thermoforming. An apparatus transfer belt is disclosed.

However, a transfer belt for an image forming apparatus that sufficiently satisfies various characteristics desired for the transfer belt for an image forming apparatus, such as a large surface resistivity, an excellent toner releasing property, and an excellent non-contamination property, has not been obtained.
JP 2002-287531 A (Claim 1)

  The present invention relates to a transfer belt for a multi-layer image forming apparatus having a base layer, an intermediate layer and a surface layer, and having a large surface resistivity, excellent toner releasing property, excellent non-contamination property, etc. The issue is to provide

  As a result of intensive studies, the present inventors have found that this problem can be achieved by forming the surface layer with a fluorine-containing polymer, and have completed the present invention.

Claim 1 of the present invention provides
On the base layer,
An intermediate layer having an elastomer;
The present invention provides a transfer belt for an image forming apparatus having a surface layer formed of a fluorine-containing polymer.

  The intermediate layer plays a role of imparting flexibility in the thickness direction, and as an elastomer of the intermediate layer, urethane, acrylonitrile butadiene rubber (NBR), ethylene rubber (EP), silicon rubber (SR), polyamide, or two of these It is particularly preferable to use the above elastomer.

  Claim 2 of the present invention corresponds to this preferred embodiment, and is the above-mentioned transfer belt for an image forming apparatus, wherein the elastomer is urethane, acrylonitrile butadiene rubber, ethylene rubber, silicon rubber, polyamide, or two or more thereof. It is an object of the present invention to provide a transfer belt for an image forming apparatus.

  As the fluorine-containing polymer that forms the surface layer, polytetrafluoroethylene (PTFE) and tetrafluoroethylene perfluoroalkyl vinyl ether (PFA) have a high (large) contact angle, and can remove toner and other deposits cleanly. This is preferable because it is possible.

  Claim 3 of the present invention corresponds to this preferred embodiment, and is the above-mentioned transfer belt for an image forming apparatus, wherein the fluorine-containing polymer is polytetrafluoroethylene (PTFE) or tetrafluoroethylene perfluoroalkyl vinyl ether ( And a transfer belt for an image forming apparatus.

  Examples of the fluorine-containing polymer that forms the surface layer include polymers and copolymers of monomers such as vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, tetrafluoropropylene, and hexafluoropropylene. Among them, a polymer of a monomer containing vinylidene fluoride, that is, a homopolymer of vinylidene fluoride (polyvinylidene fluoride) or a copolymer of two or more monomers containing vinylidene fluoride is preferably exemplified. The

  Claim 4 of the present invention corresponds to this preferred embodiment, and is the above-mentioned transfer belt for an image forming apparatus, wherein the fluorine-containing polymer is a polymer of a monomer containing vinylidene fluoride. A transfer belt for an image forming apparatus is provided.

Among the monomer polymers containing vinylidene fluoride, polyvinylidene fluoride (PVDF) is preferable because of its high contact angle.
Polyvinylidene fluoride (PVDF) has a relatively low melting point among fluorine-containing polymers, and is annealed (baked) at a temperature (about 160 ° C.) that does not deteriorate the intermediate layer such as urethane (decomposition temperature about 170 ° C.). ) Can be performed in many cases, and as a result, the toner releasing property can be improved.

  Claim 5 of the present invention corresponds to this preferred embodiment, and is the above-described transfer belt for an image forming apparatus, wherein the fluorine-containing polymer is polyvinylidene fluoride (PVDF). A transfer belt is provided.

  Among monomer polymers containing vinylidene fluoride, a copolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (THV) has a particularly high contact angle, very little bleeding, and no contamination. The properties are particularly excellent and are particularly preferable.

  Similarly to polyvinylidene fluoride (PVDF), a copolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (THV) has a relatively low melting point among fluorine-containing polymers, and urethane (decomposition temperature is about In many cases, annealing (baking) can be performed at a temperature (about 160 ° C.) that does not deteriorate the intermediate layer such as 170 ° C.), and as a result, there is also an advantage that the toner separation property can be improved.

  Claim 6 of the present invention corresponds to this preferred embodiment, and is the above-mentioned transfer belt for an image forming apparatus, wherein the fluorine-containing polymer is a copolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (THV). The present invention provides a transfer belt for an image forming apparatus.

  When the intermediate layer is formed of urethane using tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride copolymer (THV) or polyvinylidene fluoride (PVDF) as the fluorine-containing polymer, the surface layer is preferably Is easily formed by spray coating a solution of THV or PVDF on the intermediate layer.

  Claim 7 of the present invention corresponds to this preferred embodiment, and is the above-mentioned transfer belt for an image forming apparatus, wherein the fluorine-containing polymer is a copolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (THV). Or polyvinylidene fluoride (PVDF), the intermediate layer is urethane, and the surface layer is formed by spray-coating a solution of THV or PVDF on the intermediate layer. A transfer belt for a forming apparatus is provided.

  The base layer of the transfer belt for an image forming apparatus of the present invention is formed from a material having a high elastic modulus, and gives a high tensile elastic modulus to the transfer belt for an image forming apparatus. The volume resistance value of the transfer belt for the image forming apparatus can also be controlled by the material of the base layer.

  Preferred examples of the high elastic modulus material forming the base layer include polyimide (PI), polyamideimide (PAI), and polyvinylidene fluoride (PVDF).

  Claim 8 of the present invention corresponds to this preferred embodiment, and is the above-mentioned transfer belt for an image forming apparatus, wherein the base layer is polyimide (PI), polyamideimide (PAI), or polyvinylidene fluoride (PVDF). Thus, a transfer belt for an image forming apparatus is provided.

  A volume resistance value can be controlled by adding a conductive material such as carbon black (acetylene black) to a base layer formed of PI, PAI, PVDF, or the like.

  The present invention is not limited to a transfer belt for an image forming apparatus comprising only a base layer, an intermediate layer, and a surface layer, and for an image forming apparatus further provided with other layers such as a second intermediate layer according to required characteristics. A transfer belt is also included.

  Even in such a case, the thickness of the surface layer is preferably in the range of 1 to 15 μm. Within this range, sufficient wear resistance and flexibility can be achieved at the same time.

  The transfer belt for an image forming apparatus of the present invention includes a transfer fixing belt for an image forming apparatus that performs transfer and fixing simultaneously. In particular, the present invention is applied to such a transfer belt for an image forming apparatus from the viewpoint of efficiency. It is preferable to do.

  The ninth aspect of the present invention corresponds to this preferable aspect, and is the image forming apparatus transfer belt described above, wherein the image forming apparatus transfer belt is an image forming apparatus transfer fixing belt. A transfer belt for a forming apparatus is provided.

  The transfer belt of the present invention is for an image forming apparatus and has a function of transferring a toner image formed on a photosensitive drum or the like onto a transfer material such as paper. Here, examples of the image forming apparatus include a copying machine using an electrophotographic method, a laser printer, and the like. However, the image forming apparatus is not limited to these, and a toner image is formed and transferred onto a transfer material. All devices having a function of forming an image are included.

  The transfer belt for an image forming apparatus of the present invention is a multilayer transfer belt for an image forming apparatus having a base layer, an intermediate layer of an elastomer, and a surface layer formed of a fluorine-containing polymer, and the surface layer has a large surface resistivity, Excellent toner releasing properties and excellent non-staining properties can be obtained, and the intermediate layer can provide flexibility in the thickness direction.

  In particular, in recent years, toners that can cope with colorization and high image quality of image forming apparatuses have been actively developed, and among these, many have insufficient releasability and stain resistance, A single-layer transfer belt for an image forming apparatus such as polyimide or polyamideimide, or a multi-layer transfer belt for an image forming apparatus spray-coated with urethane, silicon or the like cannot sufficiently cope with these. However, according to the present invention, a transfer belt for an image forming apparatus that can sufficiently cope with these can be obtained.

  In particular, when a specific polymer such as PTFE or PFA is used as the fluorine-containing polymer, the surface resistivity, the toner releasing property and the non-staining property are particularly excellent.

  In addition, when a specific polymer such as polyvinylidene fluoride (PVDF), tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride copolymer (THV) is used as the fluorine-containing polymer, surface resistivity, toner release In addition to excellent properties and non-staining properties, there are also advantages such as facilitating processing for further improving the properties of the transfer belt for image forming apparatuses.

  Further, by using polyamide, polyamideimide or polyvinylidene fluoride for the base layer, a transfer belt for an image forming apparatus having a high tensile strength in the circumferential direction can be obtained.

  FIG. 1 is a cross-sectional view illustrating an example of a transfer belt for an image forming apparatus according to the present invention.

  The transfer belt for an image forming apparatus in FIG. 1 has a surface layer 9 and a base layer 11, and an intermediate layer 12 between the surface layer 9 and the base layer 11.

The surface layer 9 is made of PTFE.
The surface layer of the present invention preferably has a high contact angle and high smoothness, but the contact angle and smoothness of the surface layer 9 in FIG. 1 are also in this range, and as a result, excellent toner separation is achieved. Sex is obtained.

  The base layer of the present invention is preferably formed of polyimide having a modulus of elasticity of 1 to 10 GPa. The thickness of the base layer is preferably in the range of 30 to 100 μm, and particularly preferably in the range of 40 to 80 μm.

  The thickness of the base layer 11 in FIG. 1 is also within this range, and as a result, a high tensile elastic modulus in the circumferential direction of the image forming apparatus transfer belt can be imparted to the image forming apparatus transfer belt.

  The volume resistance value of the transfer belt for the image forming apparatus can be controlled by controlling the conductivity of the base layer. The conductivity of the base layer can be controlled by a method such as adding a conductive material such as carbon black.

  The intermediate layer 12 in FIG. 1 is made of aqueous urethane. The thickness of the intermediate layer of the present invention is preferably in the range of 50 to 300 μm, particularly preferably in the range of 100 to 250 μm.

  The thickness of the intermediate layer 12 in FIG. 1 is also within this range, and as a result, appropriate flexibility in the thickness direction can be imparted to the transfer belt for an image forming apparatus.

The preferable range of the volume resistance value of the base layer and the intermediate layer varies depending on the usage form of the transfer belt for the image forming apparatus. Usually, the volume resistance value of the entire transfer belt for an image forming apparatus is preferably in the range of 10 ⁸ to 10 ¹⁴ Ω · cm.

  The transfer belt for an image forming apparatus in FIG. 1 also has a volume resistance value within this range.

  The volume resistance value of the entire transfer belt for an image forming apparatus is the sum of the volume resistance values of the base layer and the intermediate layer. Accordingly, by making one considerably larger than the other and reducing the influence of the other volume resistance value on the entire volume resistance value of the transfer belt for an image forming apparatus, it is possible to control only one of the volume resistance values. It is also possible to control the volume resistance value of the entire transfer belt.

  Examples are shown below, but the present invention is not limited to the following examples. Various modifications can be made to the following embodiments within the same and equivalent scope as the present invention.

  While rotating the drum-shaped mold, apply a polyimide varnish to the outside, and then heat the mold to perform an imidization reaction to form a polyimide layer (base layer) with a thickness of 60 μm covering the periphery of the mold did. Next, a thickener was added to the aqueous urethane to obtain a viscosity of about 10 Pa · s, and after defoaming, it was coated on the polyimide layer by dipping. After coating, moisture was dried at room temperature, and further annealed at 160 ° C. to form a 200 μm-thick urethane layer (intermediate layer) on the polyimide layer.

  Next, a solution of a copolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride was spray-coated on the urethane layer under the condition that the thickness after drying and annealing was 5 μm. Thereafter, drying and annealing at 160 ° C. were performed to obtain a transfer belt of the present invention.

First, as shown in FIG. 2, a PTFE dispersion solution was applied to the inner surface of a steel outer cylinder 8 having a thermal expansion coefficient of 1.76 × 10 ⁷ / ° C. whose inner surface was mirror-finished by a dip method, and the temperature was 380 ° C. And surface layer 9 was provided.

  Further, THV was melted in butyl acetate, a film was formed on the surface layer 9 by a dipping method, and dried to provide a binder layer 14. Furthermore, the binder layer 14 was heated at 350 ° C. so that the melting points of PTFE and THV were exceeded, and both were adhered.

  Next, as shown in FIG. 3, the surface of the drum-shaped mold 10 was subjected to carbon conductive treatment to form a polyimide whose volume resistance value was adjusted, and baked at 380 ° C. to provide the base layer 11.

  Further, an aqueous urethane was applied on the base layer 11 and dried to provide an intermediate layer 12.

Next, the composite of the base layer 11 and the intermediate layer 12 provided on the surface of the drum-shaped mold 10 is peeled off from the drum-shaped mold 10, and the composite formed in a cylindrical shape is shown in FIG. It was fitted on the outer periphery of a core 13 made of nylon with a thermal expansion coefficient of 8.0 × 10 ⁷ / ° C.

  Next, as shown in FIG. 5, the core 13 fitted with the composite of the base layer 11 and the intermediate layer 12 is inserted into the outer cylinder 8 provided with the composite layer of the binder layer 14 and the surface layer 9 on the inner surface, Heated to 150 ° C. in vacuo. Due to this heating, there is a difference in thermal expansion coefficient between the outer cylinder 8 and the core 13, so that the thermally expanded core 13 presses the inner surface of the outer cylinder 8, and the composite layer of the base layer 11 and the intermediate layer 12 A composite having a four-layer structure shown in FIG. 6 of the binder layer 14 and the composite layer of the surface layer 9 was obtained.

  Next, the core 13 and the outer cylinder 8 were cooled, and a four-layer composite was separated therefrom to obtain a transfer belt for an image forming apparatus.

  The obtained transfer belt for an image forming apparatus has an intermediate layer (urethane) having a thickness of 200 μm, a binder layer (THV) having a thickness of 1 μm, and a surface layer (PTFE) having a thickness of 5 μm on a base layer (polyimide) having a thickness of 60 μm. It was possible to obtain a transfer belt for an image forming apparatus having excellent surface resistivity, toner separation and non-staining properties.

  In addition, in the said Example, the inner surface of the outer cylinder 8 is pressed with the core 13, and the composite layer of the base layer 11 and the intermediate | middle layer 12, and the composite layer of the binder layer 14 and the composite layer of the surface layer 9 is obtained. Although the difference between the thermal expansion coefficients of the core 13 and the outer cylinder 8 is used, other methods such as air pressure or a method using instantaneous explosive force may be used.

FIG. 2 is a cross-sectional view illustrating an example of a transfer belt for an image forming apparatus according to the present invention. It is a figure which shows an example of the manufacturing method of the transfer belt for image forming apparatuses of this invention. It is a figure which shows an example of the manufacturing method of the transfer belt for image forming apparatuses of this invention. It is a figure which shows an example of the manufacturing method of the transfer belt for image forming apparatuses of this invention. It is a figure which shows an example of the manufacturing method of the transfer belt for image forming apparatuses of this invention. FIG. 2 is a cross-sectional view illustrating an example of a transfer belt for an image forming apparatus according to the present invention. FIG. 2 is an explanatory diagram illustrating an outline of an image transfer method in which a transfer belt for an image forming apparatus is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Toner 2 Developing roller 3 Photosensitive drum 4 Primary transfer roller 5 Transfer belt 6 for image forming apparatus Secondary transfer roller 7 Transfer material 8 Outer cylinder 9 Surface layer 10 Drum mold 11 Base layer 12 Intermediate layer 13 Core 14 Binder layer

Claims (9)

On the base layer,
An intermediate layer having an elastomer;
A transfer belt for an image forming apparatus, comprising a surface layer formed of a fluorine-containing polymer.   2. The transfer belt for an image forming apparatus according to claim 1, wherein the elastomer is urethane, acrylonitrile butadiene rubber, ethylene rubber, silicon rubber, polyamide, or two or more kinds of these elastomers.   The transfer belt for an image forming apparatus according to claim 1 or 2, wherein the fluorine-containing polymer is polytetrafluoroethylene (PTFE) or tetrafluoroethylene perfluoroalkyl vinyl ether (PFA).   The transfer belt for an image forming apparatus according to claim 1 or 2, wherein the fluorine-containing polymer is a polymer of a monomer containing vinylidene fluoride.   The transfer belt for an image forming apparatus according to claim 4, wherein the fluorine-containing polymer is polyvinylidene fluoride (PVDF).   The transfer belt for an image forming apparatus according to claim 4, wherein the fluorine-containing polymer is a copolymer (THV) of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride.   The fluorine-containing polymer is a copolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (THV), or polyvinylidene fluoride (PVDF), the intermediate layer is urethane, and the surface layer is THV or PVDF. The transfer belt for an image forming apparatus according to claim 4, wherein the transfer belt is formed by spray-coating a solution on the intermediate layer.   8. The image forming apparatus according to claim 1, wherein the base layer is formed of polyimide (PI), polyamideimide (PAI), or polyvinylidene fluoride (PVDF). Transfer belt. 9. The image forming apparatus transfer belt according to claim 1, wherein the image forming apparatus transfer belt is an image forming apparatus transfer fixing belt.

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