JPH0285A - Heat fixing roller - Google Patents

Abstract

PURPOSE:To improve the heat resistance, non-tackiness and antistatic property of a roller body by coating the outside peripheral surface of said body with a coating compsn. which consists of fluoroplastic (a), fibrous material (b) coated with a conductive oxide, an acrylic resin (c), and a liquid medium (d) and having respectively prescribed weight ratios of (a) and (b), (a) and (c). CONSTITUTION:The outside peripheral surface of the roller body is constituted of the material consisting of the fluoroplastic (a), the fibrous material (b) coated with the conductive oxide, the acrylic resin (c), and the liquid medium (d). The weight ratio of the fluoroplastic (a) and the fibrous material (b) is specified to 95:5-50:50 and the weight ratio of the fluoroplastic (a) and the acrylic resin (c) is specified to 100:0-85:15 in this case. The heat fixing roller is constituted of the coating compsn. constituted in such a manner. Fibrous potassium titanate is used as the fibrous material (b) and tin dioxide and antimony trioxide are used as the conductive oxide. The heat fixing roller having the excellent heat resistance, non-tackiness and antistatic property is formed in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat fixing roller for a copying machine.

[Conventional technology]

2. Description of the Related Art It is known that a heat fixing roller for a copying machine has its surface coated with a non-adhesive fluororesin paint in order to prevent fused toner from adhering to the roller.

However, since fluororesin has high electrical insulating properties, it is very easy to be charged with electricity, and the same applies to the coating film made with fluororesin paint.In the heat fixing roller, the electrostatic charge can cause copy paper and toner to repel or adhere, causing abnormalities. There was a drawback. Conventionally, in order to eliminate this drawback, a conductive material has been added to the fluororesin paint. Carbon black, metal powder, etc. are used as the conductive material.

[Problem that the invention seeks to solve]

However, when carbon black is used as the conductive material, the paint has a black color, and the coating film formed on the heat fixing roller has the drawback of staining the copy paper black due to friction. Furthermore, since carbon black tends to aggregate, it has to be pulverized for a long time using a ball mill or the like in order to be uniformly dispersed in the paint, which is a manufacturing drawback.

On the other hand, when metal powder is used as a conductive material, the effect of tetraelectricity is small due to the amount added, and adding a large amount impairs the stability of the paint and reduces the mechanical strength of the coating film. It has its drawbacks.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat fixing roller that does not suffer from the above-mentioned drawbacks.

Means for Solving Problem L] The heat fixing roller of the present invention has the outer peripheral surface of the roller body made of (a) a fluororesin, (b) a fibrous material coated with a conductive oxide, and (c) an acrylic material. Consisting of an acid resin and (d) a one-body medium, the weight ratio of (a) and (b) is 95:5 to 5
0:50, and the weight ratio of (a) and (c) is 100:
It is coated with a coating composition having a molecular weight of 0 to 85:15.

A feature of the coating composition used in the present invention is that a fibrous material coated with a conductive oxide such as tin dioxide and antimony dioxide is used as the conductive material. When the conductive material is added to a fluororesin, a large conductive effect can be obtained with a small amount added. Therefore, since the addition amount can be small, it is possible to impart an antistatic function without impairing the properties of the fluororesin.

Furthermore, since the conductive material is white, a white composition can be obtained, and therefore, when coated on the roller surface, the copy paper will not be stained black due to friction.

The fibrous material has a diameter (d) of 0.01 to 10 micrometers and a length (ff) of 1 to 100 micrometers, and the higher the aspect ratio (#/d), the more preferable it is. Specific examples of fibrous substances include fibrous potassium titanate, fibrous silicon carbide, fibrous silicon nitride, fibrous α-alumina, fibrous boron carbide, etc. In particular, fibrous potassium titanate It is preferred because it has high whiteness and excellent heat resistance.

The blending ratio of the conductive material in the coating composition used in the present invention is in the range of 5 to 50% by weight, preferably in the range of 10 to 3% by weight, based on the total weight of the fluororesin and the conductive material. If the blending ratio is less than 5% by weight, no antistatic effect will be obtained, and if it exceeds 50% by weight, the smoothness, non-adhesiveness and corrosion resistance of the coating will deteriorate.

By blending the above-mentioned conductive material into the coating composition used in the present invention, the volume resistivity of 2H2 can be lowered and a sufficient antistatic effect can be obtained. It has been found that by incorporating a resin, the volume resistivity of the coating film can be further lowered and a higher antistatic effect can be obtained. In other words, the acrylic acid resin is 15% by weight or less, preferably 5% or less, based on the fluororesin.
By blending up to 15% by weight, a composition exhibiting higher antistatic ability can be obtained. The acrylic resin is not particularly limited, and examples thereof include polymethyl methacrylate, polymethyl acrylate, polyethyl acrylate, and the like.

Examples of the fluororesin that is the main component of the coating composition used in the present invention include polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and tetrafluoroethylene-hexafluoropropylene copolymer. or a mixture of these may be used.

The liquid medium used in the coating composition used in the present invention may include water or an organic solvent.

The a-containing solvent is not particularly limited, and examples thereof include toluene, benzene, xylene, and the like.

The coating composition used in the present invention is prepared into a coating material by adding coating compounding agents such as pigments, viscosity modifiers, and dispersants. This paint is usually applied by quick coating, but it can also be applied by brushing, impregnation, casting, etc.

The coating composition used in the present invention has the properties of a resin, such as non-adhesiveness, heat resistance, and chemical resistance, and also has an antistatic effect. Furthermore, this paint has the characteristic that it can be applied thickly. In the case of paints that use carbon for DL electrical materials, the thickness of the paint film must be approximately 30 to 40 μm or less because cracks occur in the coating, but in the case of this paint, the thickness of the paint film is up to approximately 100 μm. Can be painted with I¥ without causing cracks.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Reference Example 1 Fibrous potassium titanate coated with tin dioxide and antimony dioxide as a conductive material (fiber diameter: 0.3 to 0.6
μm, fiber length 10-20μm, volume resistivity lO2Ωc
40 g of a dispersant containing FFF-202) 40 (manufactured by Sumitomo Chemical Co., Ltd.) and 4.8 g of a nonionic surfactant were stirred and mixed in a mixing tank equipped with a stirring blade. This mixture was then added to a polytetrafluoroethylene aqueous dispersion (solids content 60%).
% by weight) was added and stirred and mixed in the same manner to prepare a paint. In this case, the amount of the conductive material is 40% by weight. This paint was applied onto a glass plate and baked at 380°C for 10 minutes to obtain a coating film with a thickness of about 20 μm. The volume resistivity of the resulting coating film was measured.

Next, the weights of the fibrous potassium titanate were 6.1 g (10% by weight of proprietary materials) and 15 g (2% by weight), respectively.
0% by weight) 25.7 g (30% by weight) and 60 g
(50% by weight), a paint was prepared in the same manner as above, and the volume resistivity of the paint film was measured.

The above results are shown in Figure 1. Normally, for the purpose of preventing static electricity, it is sufficient that the volume resistivity of the coating film is 10"Ωcm or less, but the volume resistivity of the coating film of this example was 106"Ωcm or less.
Since it is Ωcm or less, it can be said that this coating composition has a sufficient antistatic effect.

Reference Example 2 6 g of polymethyl acrylate was added to the composition of Example 1.
After adding and stirring and mixing, the volume resistivity of the coating film was measured in the same manner as in Example 1.

The measurement results are shown in Figure 1. From these 71111 results, it can be seen that an even greater antistatic effect can be obtained by adding acrylic acid resin.

Comparative Reference Example 1 Instead of fibrous potassium titanate as a conductive material, the surface of granular mica fine powder with an average particle size of 10 μm was coated with tin dioxide and antimony dioxide (MBC-300 manufactured by Teikoku Kako Co., Ltd., volume resistivity was made into a paint in the same manner as in Example 1, and the volume resistivity of the paint film was measured.

The measurement results are shown in Figure 1. This result shows that when a granular material is used as a conductive material, the volume resistivity of the coating film is higher than when a fibrous material is used, and the remarkable antistatic ability as achieved in the present invention cannot be obtained.

Example 1 An aluminum roller body with an outer diameter of 40 mm and a length of 340 mm was subjected to normal surface treatment (blasting, primer coating) for coating with fluororesin, and then manufactured in the same manner as in Reference Example 1. Paint (Conductive material blending ratio: 40
% by weight) was applied by a conventional method. The film thickness was approximately 30 μm.

Example 2 A roller was produced in the same manner as in Example 1 except that the paint was replaced with a paint produced in the same manner as in Reference Example 2.

Comparative Example 1 A roller was produced in the same manner as in Example 1, except that a conductive material was not mixed in the paint of Reference Example 1.

Test Example The rollers prepared in Example 1, Example 2, and Comparative Example 1 were charged by rubbing with nylon felt, and then the surface charging potential was measured using a surface electrometer (manufactured by Trek). . The results are shown in Table 1.

The closer the surface charge potential in Table 1 is to 0, the smaller the charge amount is, indicating that toner is less likely to adhere to the roller.

(Effects of the Invention) The heat fixing roller of the present invention has excellent heat resistance, non-adhesiveness, and antistatic effect, and is resistant to staining due to toner adhesion and has good durability.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the blending ratio of the conductive material and the volume resistivity of the coating film in Reference Example 1, Reference Example 2, and Comparative Reference Example 1. Patent applicant: Daikin Industries, Ltd.
1 total amount (weight (n2)

Claims (1)

[Claims] 1. The outer peripheral surface of the roller body is made of (a) fluororesin, (
b) a fibrous material coated with a conductive oxide, (c) an acrylic resin, and (d) a liquid medium, comprising (a) and (b)
The weight ratio of (a) and (
c) A heat fixing roller coated with a coating composition having a weight ratio of 100:0 to 85:15. 2. The heat fixing roller according to claim 1, wherein the fibrous material is fibrous potassium titanate. 3. The heat fixing roller according to claim 1, wherein the conductive oxide is tin dioxide and antimony trioxide.