JPH02253285A - Thermal fixing roll - Google Patents

Abstract

PURPOSE:To obtain a thermal fixing roll by which a high definition picture can be obtained even when its diameter is decreased by providing the outer layer composed of a fluororesin tube on the surface of a sponge roll, and the inner layer of the room temp. curing liquid rubber of excellent adhesion injected into between a sponge layer and the fluororesin tube. CONSTITUTION:The silicone sponge layer 2 is cylindrically provided on the outer periphery of a metal core, and the silicone rubber layer 3A and the tube layer 3B of perfluoroalkoxyl resin are provided thereon in this order. The outer layer 3B prevents toner from staining the surface of the sponge layer 2 as a base layer, while exhibiting enough releasability from the toner without being affected by silicone oil, etc., even when it coated with them. The inner layer 3A is composed by injecting the room temp. curing liquid rubber of excellent adhesion into a space between the sponge layer 2 and the outer layer 3B and setting: The fluororesin tube is firmly fixed onto the surface of the roll by the inner layer 3A with its enough adhesion without damaging the resiliency of the base layer.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Field of Application) The present invention relates to a heat fixing roller used, for example, in a heat fixing section of an electronic copying machine. The present invention relates to a heat fixing roller formed with a heat fixing roller.

(Prior Art) Several methods have been developed as image fixing methods for electronic copying machines, etc., but the fixing method using a heat fixing roller is the mainstream. The thermal fixing roller fixing method has many advantages such as excellent fixing ability and safety, no special chemicals are required, and the structure of the device can be made compact.

In recent years, such heat fixing rollers have been used to improve image quality,
In response to market needs such as miniaturization of equipment, soft rollers are attracting attention because they can provide high-quality images and can easily maintain a sufficient nip width even when the diameter is reduced.

A soft roller has a structure in which a heat-resistant elastic layer made of silicone rubber is coated on a metal core shaft.Since it is soft, the outermost layer of silicone rubber wraps around the toner and dissolves it, suppressing gloss and image enlargement. However, the properties of silicone rubber, such as its releasability with toner, heat resistance, and mechanical strength, are not necessarily sufficient, and it is generally hard They have the disadvantage of having a shorter lifespan than rollers. Another problem is that it is necessary to apply silicone oil to the surface of the roller during use in order to improve the releasability of the roller from the toner.

For this purpose, as shown in Fig. 2, a cylindrical sponge layer 2 is provided around the outer periphery of a metal core shaft 1 made of aluminum or the like, and a silicone rubber or fluororesin tube (unexamined Japanese Patent Application Publication No. A soft roller has been developed that has a structure in which a non-sponge layer 3 made of (Sho 60-186883) is provided with improved durability and releasability from toner.

(Problems to be Solved by the Invention) However, soft rollers provided with a surface layer of silicone rubber are still insufficient in terms of releasability from toner, and in order to obtain a roller with low hardness, the thickness of the surface layer is If the thickness of the surface layer is made thinner, it will swell with the applied silicone oil, further reducing its durability.If the surface layer is made thicker to a certain extent to increase its durability against silicone oil, it will not only increase the hardness of the roller, but also reduce the heat of the heat fixing roller. There was a problem in that the conductivity deteriorated, and as a result, the temperature of the roller surface became unstable, resulting in poor heat fixing properties.

In addition, with soft rollers that use fluororesin tubes for the surface layer, the silicone rubber that makes up the base sponge layer is foamed at around 200°C during manufacturing, so wrinkles tend to occur on the surface of the fluororesin tube. (However, there was a problem in that it was difficult to form a smooth roller surface.Furthermore, fluororesin has poor adhesion to the sponge layer, so simply applying a primer will not provide sufficient adhesion, and when used. There was also the problem that the sponge layer and the resin layer peeled off at the interface, reducing durability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fluororesin-coated heat fixing roller that overcomes these drawbacks of conventional rollers, has good heat fixability, provides high-quality images, and has a long life.

[Structure of the Invention] (Means for Solving the Problems) That is, the heat fixing roller of the present invention is a heat fixing roller in which a cylindrical sponge layer and a non-sponge layer are sequentially provided on the outer periphery of a metal core shaft. The layer is an outer layer made of fluororesin tubes coaxially arranged at intervals around the outer circumference of the cylindrical sponge layer, and a room temperature curing liquid, a rubber liquid, is injected into the gap between this outer layer and the sponge layer and hardened. It is characterized by comprising an inner layer formed by

Examples of fluororesin tubes that can be used in the present invention include PPA (perfluoroalkoxy resin) tubes having a thickness of 25 to 200 μm. The inner surface of the PF^ tube is etched and a primer is applied to improve its adhesion to the sponge layer.

The inner diameter of the PPA tube to be used is preferably about 0.5 to 5 cm larger than the outer diameter of the sponge roller inserted inside.

In the present invention, LTV silicone rubber liquid is suitable as the room-temperature curing liquid rubber injected into the gap between the PFA tube and the sponge layer, and at a temperature of 30±10°C,
More preferably, the sponge layer is cured at a temperature of 30±5°C, and if necessary, a post-heat treatment is performed.
Foaming may be completed before installation into the mold, or foaming may be finished after injection into the mold.

(Function) In the heat fixing roller of the present invention, the cylindrical sponge layer on the metal core shaft reduces the hardness of the roller, and the outer layer made of a fluororesin tube prevents the surface of the base sponge layer from being contaminated by toner. Even when coated with silicone oil, etc., it is not affected by the oil and exhibits sufficient releasability from the toner. Furthermore, the inner layer is made by injecting and hardening a room-temperature curing liquid rubber solution with excellent adhesiveness into the gap between the base sponge layer and the outer fluororesin tube, without impairing the elasticity of the base layer. Fix the fluororesin tube to the roller surface with sufficient adhesive force.

(Example) Examples and comparative examples of the present invention will be described below with reference to the drawings.

Embodiment FIG. 1 is a sectional view of a heat fixing roller according to an embodiment of the present invention. In the roller of the present invention, a silicone rubber sponge layer 2 is provided in a cylindrical shape around the outer periphery of a metal core shaft 1, and LT
V-based silicone rubber layer 3A.

and PPA tube layer 3B are provided in this order.

The roller of this example was manufactured as follows.

First, inside a cylindrical mold with an inner diameter of 50.5-1, a PFA tube 3B having the same outer diameter as the hollow mold and a thickness of 50 μm was installed.

The inner surface of the tube 3B was previously etched and coated with a primer. On the other hand, on the metal core shaft, the outer diameter is 47mm-1.
Hardness 27 (ASKER-C hardness meter scale.

Prepare a roller with a silicone rubber sponge layer formed thereon (the same applies hereinafter), place it coaxially in the above cylindrical mold, and apply an LTV silicone rubber liquid (product name: XE15-636) with a hardness of 18 from the bottom of the mold. 3A (manufactured by Toshiba Silicone Co., Ltd.) was injected and held at 30° C. for 15 hours to cure. After cold stringing, the mold was removed and heat treated at 200°C for 4 hours to reduce the outer diameter to 50.
A roller of the present invention having a hardness of 11% and a hardness of 35 was obtained.

The roller obtained in this way was installed in a 40 ppm electronic copying machine, coated with high viscosity silicone oil, and
When we conducted a paper-feeding test on an actual machine using vertical paper passing, no peeling of the PPA coating or thinning of the outer diameter of the roller was observed even after 300,000 sheets were passed.

Comparative Example 1 A silicone rubber roller having an LTV-based silicone rubber layer with an outer diameter of 50-1 and a thickness of 5 mg + s hardness of 40 on the core bar was subjected to an actual machine paper passing test under the same conditions as in the example.
At the time of passing 200,000 sheets, the outer diameter of the roller was found to be narrowed by 0°4-I, and when A3 size paper was passed vertically, wrinkles occurred in the paper.

Comparative Example 2 L with an outer diameter of 50 m, a rubber layer thickness of 1.5 m, and a hardness of 40
When a sponge roller (sponge layer thickness: 3.5 ms) having a TV-based silicone rubber layer as a surface layer was subjected to an actual paper feeding test under the same conditions as in the example, toner stains occurred after 80,000 sheets were passed. After 120,000 sheets had been passed, even the back side of the copy paper became dirty, so it was determined that the product's lifespan had reached its end.

Comparative Example 3 Outer diameter 2nl 1% Rubber layer thickness 6+u+s Hardness 1g-L
On the base layer made of TV-based silicone rubber, a thickness of 50 μ-
A roller coated with a PPA tube as a surface layer (hardness of the roller measured on the roller is 38) was attached to a lOppm electronic copying machine, and an actual machine paper passing test was conducted under the same conditions as in the example. It was unusable due to poor fixing.

Comparative Example 4 A PFA tube 3B having a thickness of 50 μl and having the same outer diameter as the hollow mold was placed inside a cylindrical mold having an inner diameter of 50.5 ms. On the other hand, a metal core shaft coated with millable type 11TV silicone rubber mixed with a foaming agent was prepared, and this was placed coaxially in the cylindrical mold and held at 180°C for 3θ minutes to foam and create a sponge with a surface layer. Although a roller was obtained, the PPA tube surface of the obtained roller was wrinkled and could not be used as a heat fixing roller.

[Effects of the Invention] As explained above, according to the present invention, an outer layer made of a fluororesin tube is provided on the surface of the sponge roller, and a room temperature curing liquid rubber liquid with excellent adhesiveness is provided in the gap between the sponge layer and the fluororesin tube. The non-sponge surface layer consists of two layers, the inner layer is formed by injecting and curing the material, so even when the diameter is small, high-quality images can be obtained, and it also has high reliability and a long service life. This can be achieved without the need for special equipment or techniques.

[Brief explanation of drawings]

FIG. M41 is a sectional view of a roller according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional sponge roller with a surface layer. l...Metal core shaft 2...Sponge layer 3...Non-sponge layer 3A...LTV silicone rubber layer・3B・・
...PFA tube layer

Claims (1)

[Claims] (1) In a heat fixing roller in which a cylindrical sponge layer and a non-sponge layer are sequentially provided on the outer periphery of a metal core shaft, the non-sponge layer is coaxially arranged at intervals on the outer periphery of the cylindrical sponge layer. A liquid rubber solution that cures at room temperature is injected into the gap between the outer layer made of a fluororesin tube and the sponge layer. A heat fixing roller comprising an inner layer formed by hardening.