JPH063397Y2 - Fixing belt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is a fixing belt used in a fixing unit for fixing an image transferred to a transfer object used in an electrophotographic copying machine, a facsimile, a printer, or the like. Or, it relates to a sleeve (hereinafter, simply referred to as a belt).

<Prior Art> In electrophotographic copying machines, facsimiles, printers, etc., for example, as shown in FIG.
An electrostatic image is formed on the electrostatic image, and the electrostatic image is formed on the image forming unit 12.
After the toner image is developed as a toner image by the transfer unit 13 and the toner image is transferred to the transfer target 14 such as paper by the transfer unit 13, the transfer unit 14 fixes the transfer image on the transfer target 14 to fix the transfer target. It has gained.

As shown in FIG. 4, the conventional fixing unit 15 is composed of a pair of heat rolls 16 and a pressure roll 17 made of silicone rubber, and roll-fixing is employed to fix the transfer target 14 by sandwiching it. Has been done.

However, in this roll fixing, the pressing force of the pressure roll 17 is strong, so that there is a problem that, for example, a thin line is crushed and the image becomes unclear. Therefore, in recent years, the heat roll 18 and this heat roll as shown in FIG. Belt fixing, which is composed of a belt 19 that covers the roll 18 so as to partially cover the roll 18, is adopted.

Since this belt fixing allows a large contact area, the pressing pressure of the pressure belt 19 may be weak, and is suitable for precise copying, or particularly for Osaka paper, for example, AO paper.

The pressure belt 19 used for this belt fixing is generally made of a millable silicone rubber (HTV) as a raw material, and is molded by extrusion molding or sheet winding molding and then polished.

<Problems to be Solved by the Invention> The pressure belt 19 described above is used while supplying silicone oil to the surface thereof in order to improve releasability to toner, but the belt 19 absorbs silicone oil. There is a problem of swelling and shortening the life.

Further, it may be possible to coat the surface of the pressure belt 19 with a fluororesin in order to improve the releasability, but there is a problem that it becomes expensive.

Further, since the silicone rubber forming the pressure belt 19 is an elastic body, it stretches due to long-term use, causing a problem of unstable running.

Meanwhile, in the fixing unit 15 described above, a mechanism using a heating belt on the heat roll side is also known. This heating belt is a heat roll having a heater inside,
A toner image is fixed between a pressure roll and a heat roll, which are wound around an auxiliary roll provided at regular intervals and face the heat roll via the heating belt. .

Since such a heating belt is required to have high thermal conductivity, it needs to have a small thickness, but like the above-mentioned pressure belt 19, it has good releasability for toner and has a long life, and is simple. In addition, it is required to have a characteristic that it can be manufactured at low cost.

In view of such circumstances, the present invention has an object to provide a pressure belt and a heating belt (hereinafter, both are referred to as a fixing belt) that are inexpensive, have a long life, and have stable traveling properties.

<Means for Solving the Problems> A fixing belt according to the present invention that achieves the above-mentioned object is a fixing belt used in a fixing unit for fixing a toner image transferred to a transfer target, and is made of a polyamideimide resin. It is characterized by comprising a belt body and a silicone rubber layer coated on the surface of the belt body.

In the present invention, by adopting a polyamide-imide resin for the belt body of the fixing belt, the performance of heat resistance and silicone oil resistance is improved, and the life is extended. Further, since the belt body made of polyamide-imide resin has a high Young's modulus, elongation does not occur and stable running can be realized.
Further, since the silicone rubber coated on the surface of the belt does not constitute the belt itself, it is possible to positively use the one having a good releasability for toner, so that the releasability is improved as compared with the conventional belt. .

As shown in FIG. 1, the fixing belt of the present invention preferably has a belt body 1 formed by centrifugal molding using a polyamideimide resin as a raw material, and liquid silicone rubber is spray-coated on the surface of the belt body 1. It is manufactured by forming the silicone rubber layer 2.

Here, the centrifugal molding method is to inject a solution in which a raw material resin is dissolved in a volatile solvent into a cylindrical mold, and the cylindrical mold is filled with, for example, 110-110.
It is a method of rotating while heating to 130 ° C. for semi-vulcanization, demolding, and then performing main vulcanization.

At this time, in particular, in order to manufacture a thin seamless belt with a high accuracy and a uniform thickness, Japanese Patent Publication No. 60-1545
No. 4, in which a liquid curable silicone rubber is first injected into a cylindrical mold and cured to form a mold surface, and centrifugal molding is performed using the mold surface as described above. Good.

Further, the silicone rubber layer provided on the surface of the belt body may be formed by coating liquid silicone rubber by a commonly used coating method such as a spray coating method. This silicone rubber layer is 50-100μ
The addition type liquid silicone (KE-1300 manufactured by Shin-Etsu Chemical Co., Ltd.) can be exemplified as a suitable material.

When this fixing belt was used as a pressure belt by mounting it on a tester, it was easy to release from the toner, and stable running was realized even after long-term use.

<Effects of the Invention> As described above, the fixing belt of the present invention can be manufactured at low cost, has high releasability, and has a long life, and can realize stable running for a long period of time.

[Brief description of drawings]

FIG. 1 is a side view showing a fixing belt according to the present invention, FIG. 2 is a sectional view of a centrifugal molding apparatus used in an embodiment, FIG. 3 is a schematic view of a copying section, and FIG. 4 is roll fixing. FIG. 5 and FIG. 5 are explanatory views showing belt fixing. In the drawings, 1 is a belt body and 2 is a silicone rubber layer.

Claims (1)

[Scope of utility model registration request] 1. A fixing / pressurizing belt for fixing an electrostatic image transferred to an object to be transferred, comprising: a belt body made of polyamideimide resin; and a coating layer of silicone rubber formed on the surface of the belt body. Characteristic fixing and pressure belt