JP2004212430A - Belt for fixing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt for fixing realizing excellent cushioning function, further improvement of strength in the direction of the diameter of the belt and reduction of cost. <P>SOLUTION: A base material layer consisting of metal wire functioning as a stretching suppressing material in the direction of the diameter of the belt is installed in a thick part of the fixing belt. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fixing belt used in a fixing unit that fixes a toner image transferred onto a transfer material such as transfer paper by heating in an image forming apparatus such as an electrophotographic copying machine, a facsimile, or a printer.
[0002]
[Prior art]
Conventionally, a fixing belt in which a heat-resistant elastomer layer composed of a soft segment and a hard segment is formed on an outer peripheral surface of a cylindrical polyimide tube via an adhesive layer composed of a heat-resistant synthetic resin layer is known. (See Patent Document 1)
However, the above-mentioned fixing belt has a problem that it expands in the radial direction at high temperature and high pressure. Also, this belt has a problem that the fixing property is poor because the cushioning property is poor. Further, there is a problem that the cost of the product increases because the polyimide resin is expensive, and that the productivity is poor because the manufacturing process is complicated.
While the above problems are being solved, recent image forming apparatuses such as electrophotographic copiers, facsimiles, and printers have a reduced warm-up time (quick start) to eliminate the need for a heater pre-heating step. There is a need for a fixing belt that satisfies the requirement of further increasing the radial strength of the belt while realizing power consumption. In order to shorten the warm-up time described above, there is an electromagnetic induction heating method (hereinafter, referred to as an IH method) as a method for warming the belt, but there is a problem of high cost and unresolved durability.
[0003]
[Patent Document 1]
JP-A-10-161448
[Problems to be solved by the invention]
Accordingly, a first object of the present invention is to provide a fixing belt that achieves excellent cushioning properties, further improved strength in the belt radial direction, and reduced cost.
Further, a second object of the present invention is to provide a fixing belt which can durably cope with the IH system in addition to the above-mentioned objects.
[0005]
[Means for Solving the Problems]
The present inventors have paid attention to disposing a base layer made of a metal wire that functions as a material for suppressing elongation in the radial direction of the belt in the thick portion of the fixing belt, and as a result, have alleviated the conventional problems. Has been resolved.
[0006]
Thus, according to the present invention, a base layer made of a metal wire for suppressing at least radial elongation of the belt is disposed in the thick part of the belt, and at least the inner layer of the belt is made of heat-resistant rubber-like elastic material. There is provided a fixing belt characterized by being constituted by a body.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view showing an example of the fixing belt of the present invention, wherein (1) is an inner layer portion, (2) is a metal base material layer that suppresses at least radial (circumferential) elongation of the belt, and , (3) are outer layer portions.
A first feature of the present invention is that a metal base layer (2) that suppresses at least radial expansion of a fixing belt is disposed between an inner layer portion (1) and an outer layer portion (3). At least the inner layer (1), that is, the inner peripheral surface of the belt is formed of a heat-resistant rubber-like elastic body. Here, the radial elongation of the belt is caused by the heat-resistant rubber-like elastic material provided in the inner layer portion (1).
Further, a second feature of the present invention is that the metal base layer (2) is used as a metal part in which an eddy current is generated by an IH method due to magnetic lines of force generated by a metal coil, that is, a conductive heat-generating member. The belt is heated by heat generated by the electric resistance of the belt. Here, the "conductive heating member in the IH system" means that an electric current flows through a metal coil by the IH system, and an eddy current is generated in the other metal by the lines of magnetic force generated here. Refers to the "one metal" when it is converted into heat. In the present invention, as the “one metal”, heat is generated by using an elongation suppressing base material layer (hereinafter, referred to as a metal base material layer) composed of a metal wire to heat the belt.
In the present invention, by adopting the above configuration,
a. The inner layer of the belt is made of a heat-resistant rubber-like elastic body, so that the belt exhibits improved gripping properties (slip prevention ability) with respect to the roller on which the belt is suspended, and b. In the thickness direction, the cushioning property is ensured, so that there is no fear of crushing the toner, and a good fixing property is obtained, and c. By the interposition of a metal base layer that suppresses at least radial elongation of the belt, the elongation of the rubber-like elastic body is reliably suppressed even under high temperature and high pressure, and d. It is possible to realize a fixing belt that can easily cope with the IH system without requiring any special accessory parts.
A stainless wire is preferably used for such a metal base layer (2). Examples of the structure of the metal base layer (2) include a horizontally wound layer, a horizontally wound layer appropriately provided with a vertical attachment, and a seamless aggregate structure such as a braided layer. The structure itself may be not only the illustrated single layer but also a plurality of layers independent of each other.
Here, the reason why the braided layer or the horizontally wound layer made of a metal wire is effective in preventing elongation is as follows. The first reason is that the metal expands significantly less than the silicone rubber due to heat, and the second reason is that the metal has excellent mechanical strength. By braiding or horizontally winding a metal wire having these characteristics on a rubber-like elastic material such as silicone rubber, it is possible to prevent the silicone rubber from stretching when the fixing belt is heated.
In this case, in terms of productivity and cost, the horizontal winding layer and the braided layer are more effective as further suppressing effects of elongation. Therefore, these structures may be appropriately used depending on the required characteristics of the belt. Further, the wire diameter of the metal wire may be about 10 μm to 200 μm, the thickness of the braid may be about 10 μm to 300 μm, and the final thickness of the metal base material layer (2) is preferably adjusted to a range of 10 μm to 500 μm. . The metal base layer (2) does not need to be composed only of a metal wire, and a heat-resistant non-stretchable material such as glass fiber may be used in the form of a glass cloth. The combined use of this glass fiber has the advantage of suppressing elongation in the radial and longitudinal directions and further improving the strength. Further, the metal base layer (2) itself may be embedded in a heat-resistant resin layer or a heat-resistant rubber-like elastic layer described later, whereby the effect of suppressing elongation is further emphasized. The heat-resistant resin used at this time is not particularly limited as long as it is generally called a heat-resistant resin, and among them, a polyimide resin is preferably used. The composite buried layer is formed, for example, by impregnating or coating the above-described horizontal winding layer or braided layer with a polyimide varnish.
In the present invention, examples of the heat-resistant rubber-like elastic body provided in the inner layer portion (1) include silicone rubber and fluorine rubber, but from the viewpoint of cost, silicone rubber is more preferable. The thickness of the inner layer portion (1) is desirably in the range of 10 μm to 300 μm in consideration of both grip performance and strength. On the other hand, in the outer layer portion (3), a heat-resistant resin such as polyimide is arranged in addition to the heat-resistant rubber-like elastic body. In this case, the fluororesin is preferred when the releasability from the toner is prioritized, the polyimide resin is particularly preferred when high heat resistance is required, and the silicone rubber is preferably used when cost is important. . The thickness of the outer layer portion (3) is preferably in the range of 10 μm to 300 μm in consideration of both the releasability and the durability.
Here, specific examples of the fluororesin include tetrafluoroethylene resin (PTFE), tetrafluoroethylene / perfluoroalkoxyethylene copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP) and the like. Can be Among these, a tetrafluoroethylene / perfluoroalkoxyethylene copolymer (PFA) is particularly preferred from the viewpoint of releasability and flexibility. Further, as the polyimide resin, "Toraynis # 3000" (trade name) manufactured by Toray Industries, Inc. and "SKYBOND" (trade name) manufactured by IS.T, and as the silicone rubber, "RTV (manufactured by Shin-Etsu Chemical Co., Ltd.) X-2018) "and" RTV (X32-1032) "(all are trade names).
The thickness of the entire fixing belt made of the above-mentioned materials is 500 μm or less, preferably 50 μm to 300 μm, and more preferably 50 μm to 150 μm. If the thickness is too small, the strength of the belt becomes weak, and if it is too large, the thermal conductivity of the belt decreases.
Next, a method for manufacturing the fixing belt of the present invention will be described with reference to an example.
First, a liquid silicone rubber is coated on a tubular body (an aluminum core coated with a PFA resin) conforming to the required belt inner diameter. Next, the coated silicone rubber is flowed and solidified to form the inner layer portion (1). A metal wire, for example, a stainless wire such as SUS304WPB, SUS304W1 or SUS304W2 is wound around the inner layer portion (1) in a circumferential direction in a horizontal winding manner to form a metal base material layer (2). Thereafter, the liquid silicone rubber is coated again, and then vulcanized and solidified, and the silicone rubber layer is impregnated and solidified. The metal base layer (2) and the surface of the base layer (2) are made of silicone rubber alone. An outer layer (3) is formed. Finally, the fixing layer belt of the present invention is obtained by pulling out the three-layer structure from the tubular article. Then, the belt may be subjected to finishing treatment such as surface polishing as necessary.
In the above aspect, when the inner layer portion (1) may be relatively thin, the metal wire is loosely wound or braided so that a gap is formed between the inner layer portion and the outer peripheral surface of the tubular body. With the base layer (2) formed, liquid silicone rubber may be coated to a thickness greater than the thickness of the metal base layer (2). In this case, the silicone rubber filling the gap becomes the inner layer (1), and the silicone rubber overlaid on the outer peripheral surface of the metal base layer (2) becomes the outer layer (3).
[0008]
Hereinafter, specific examples of the fixing belt of the present invention will be described.
In the above-described manufacturing method, the inner layer portion (1) is a silicone rubber layer having a thickness of 100 μm and a width of 350 mm, and a metal wire (SUS304WPB) having a diameter of 50 μm is wound around the outer periphery of the silicone rubber layer in a single layer. A metal base layer (2) having a thickness of 120 μm to 150 μm was formed. Further, an outer layer portion (3) of silicone rubber having a thickness of 70 μm is formed on the outer periphery of the metal base material layer (2), and a cylindrical fixing belt having a total belt thickness of 190 to 220 μm and a width of 350 mm. It was created.
When the adhesive strength between the layers of the fixing belt thus produced was measured by a 180 ° peel test, it was 587 gf / cm in all cases, and a sufficient adhesive strength was obtained. Further, when this belt was used in an actual machine (copying machine), it was confirmed that no slippage of the belt occurred and that the fixing property of the image was good due to the sufficient elasticity of the silicone rubber layer. Further, as a result of applying the method to the IH method, the belt is heated in a very short time by electromagnetic induction heating by the metal base layer functioning as a conductive heat generating member in the belt, thereby eliminating the need to raise the temperature of the heater in advance. Therefore, it was confirmed that power consumption was reduced.
[0009]
【The invention's effect】
In the present invention, while ensuring improved grip and cushioning properties by a heat-resistant rubber-like elastic body disposed on the inner layer portion of the belt, the problem of belt elongation, which is a concern with the use of the elastic body, is solved by a metal wire. It was eliminated by introducing a metal base layer made of an inexpensive material, so it does not elongate even when used under high temperature and high pressure, and at the same time, it has excellent fixability without slippage. A belt is provided. Moreover, the metal base layer functions as a conductive heating member that generates heat by eddy current generated by applying a magnetic field according to the IH method, and the belt is short-circuited by heat generated by the electric resistance of the metal base layer. Since the belt is heated in a short period of time, it can meet the needs of low power consumption and has a simple structure, so that workability in manufacturing is remarkably improved and productivity is also improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an example of a fixing belt of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 Inner layer portion of fixing belt 2 Base layer made of metal wire that functions as a material for suppressing radial expansion of fixing belt and also serves as a conductive heating member in the IH method 3 Outer layer portion of fixing belt

Claims (8)

In the thick part of the belt, a base layer made of a metal wire that suppresses at least radial elongation of the belt is arranged, and at least the inner layer part of the belt is made of a heat-resistant rubber-like elastic body. Characteristic fixing belt. The fixing belt according to claim 1, wherein the base layer is a composite layer formed by using a glass cloth in combination with a metal wire. The fixing belt according to claim 1, wherein the base layer is embedded in a heat-resistant rubber-like elastic body or a heat-resistant resin layer. The fixing belt according to claim 1, wherein the metal wire is in a horizontal winding state. The fixing belt according to claim 1, wherein the metal wire is in a braided state. The fixing belt according to claim 1, wherein the metal wire functions as a conductive heat generating member in an IH system. 7. The fixing belt according to claim 1, wherein an outer layer portion of the belt is made of a heat-resistant rubber-like elastic body or a heat-resistant resin. The fixing belt according to claim 1, wherein the thickness of the belt is 500 μm or less.

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