JPS5824174A - Manufacture of fixing roller - Google Patents

Abstract

PURPOSE:To obtain a fixing roller with high scratch and wear resistances by electrostatically coating the surface of a roller with a powdered mixture of an ethylene tetrafluoride-perfluoroalkoxyethylene copolymer with carbon fluoride and by baking the coat. CONSTITUTION:Powder of an ethylene tetrafluoride-perfluoroalkoxyethylene copolymer is mixed with powder of carbon fluoride in about 100:2-100:20 weight ratio. The surface of a metallic roller of Al or the like is coated with the powdered mixture by electrostatic powder coating, and the coat is melted and calcined at 330-380 deg.C. By this method the nonstickiness of the resin is increased, and a fixing roller having high scratch and wear resistances and a long life for an electrophotographic copier or facsimile is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a fixing roller for an electronic copying machine, facsimile machine, etc.

2. Description of the Related Art In electrostatic type electronic copying machines and the like, a method that has recently been frequently used to fix a toner image formed on a sheet of paper is to use a heated roller. In this fixing method, paper on which a toner image has been formed is passed between two rollers pressed together, and one or both of the rollers is heated from the inside to fuse the toner image onto the paper.

This fixing method has many advantages over other oven-based fixing methods, such as high thermal efficiency and easy speed-up, and it is rarely used in modern electronic copying machines. A fixing method using a roller is used. Usually, the fixing roller is made of metal such as stainless steel or aluminum and its surface is coated with a non-adhesive substance such as silicone rubber or fluorocarbon resin to prevent offset. Conventional fixing rollers have the following problems.

For those covered with silicone oil, the surface is sufficiently non-adhesive, and if left as is, an offset phenomenon will occur, so apply a liquid such as silicone oil to the surface of the four-layer to prevent off-setting. It was used as a fixing reeler. For this reason, it is necessary to provide a silicone oil application device in the fixing portion, which poses a problem of complicating the device.

In addition, although products coated with fluorocarbon resin have better non-adhesive properties than silicone rubber, they are still not sufficient, and depending on the type of toner, it may be necessary to apply silicone oil, which is better than silicone rubber. I had a similar problem.

Furthermore, there is a problem in that fluorine-based resin-coated materials are less flexible than silicone rubber and are therefore more susceptible to scratches.

The fluorine-based resin used here needs to have a continuous usable temperature of about 200°C or higher, which is necessary for the fixing roller, so tetrafluoroethylene II resin,
Tetrafluoroethylene-barfed tetraalkoxyethylene copolymer (hereinafter abbreviated as PFA resin) or tetrafluoroethylene-hexafluoropropylene resin (hereinafter abbreviated as FEP resin) is preferred, and among these, PFA resin is particularly preferred.

The reason for this is that PFA has greater heat resistance than FEP resin, and is also non-adhesive and less sticky than tetrafluoroethylene resin.
The heat resistance and other properties are almost the same, but when used as a fixing roller, it is resistant to scratches and has a long life as a ronilla.

However, the fixing roller coated with PFA resin still has the problem of scratches (particularly the separation claws).

The present inventors have further improved the non-stick properties of PFA resin,
As a result of researching a fixing roller with increased scratch resistance and abrasion resistance, the present invention was completed.60 The feature of the present invention is that the outer surface of the metal roller is made of tetrafluoroethylene bar 70 loalkoxyethylene copolymer (PFA resin). )
This method is characterized by applying a mixed powder of carbon and fluoride by electrostatic powder coating, and then baking this at a temperature of 330° C. or more and 880° C. or less.

Of course, as a pretreatment for coating this mixed powder, the surface is roughened by sandblasting, and if necessary, a fluorine resin primer is applied.
1 What is PFA resin in the present invention? Tetrafluoroethylene has the same chemical resistance as western fluoroethylene resin, and has a high point when it melts easily compared to tetrafluoroethylene resin. When used as a fixing roller compared to ethylene resin,
It is characterized by long life.

Next, in the present invention, fluorinated carbon is an inorganic polymer represented by (CF)n consisting of carbon and fluorine, and includes natural graphite, graphite fiber, petroleum coke, charcoal, carbon binder, carbon It is a solid fluoride obtained by reacting fluoride gas with raw material carbon such as black.

In the present invention, this is added to PFA resin, and the greatest feature of the present invention is that when the mixed powder of PFA and fluorocarbon is painted and baked, the temperature is 380°C or higher and 880°C.
The point is that:

Seizing occurs when the temperature exceeds 580°C, thermal decomposition of carbon fluoride occurs, and fluorine atoms are released from carbon fluoride.
It has been found that a problem arises in that the non-adhesiveness, which is a major feature of fluorocarbon, is reduced. Therefore, when the baking temperature exceeds 875 DEG C., the non-adhesive property, which is an important characteristic of a fixing roller, decreases, and there is a problem in that offset is more likely to occur.

On the other hand, for baking, if the temperature is below 880'C, PFA
If the melting is insufficient and the resulting resin layer on the surface is soft and used as a fixing roller, there is a drawback that it is easily scratched and has a short service life.

For the above reasons, the baking temperature of the present invention is 88.
A temperature of 0°C or higher and 880'C or lower is required.

The amount of fluorinated carbon to be added is preferably 2% by weight or more and 20% by weight or less based on the PFA resin.

The reason for this is that when 2% by weight is ungrooved, the effect of fluorocarbon addition is hardly seen, and when it exceeds 20% by weight, the adhesive strength between the base material and the resin decreases. However, this is because there is a further drawback that the wear resistance is lowered.

Next, a method for manufacturing such a fixing reeler will be described in more detail. The surface of the metal four-layer serving as the base material is roughened by sandblasting or etching to improve adhesion to the fluorocarbon resin. Furthermore, if necessary, a primer can be applied to further increase the adhesive strength.

Furthermore, as a mixed powder of PFA and carbon fluoride,
Electrostatic powder coating is suitable.

The fixing roller of the present invention can be manufactured by applying a fluorocarbon-added fluorocarbon resin to the outer surface of the metal roller pretreated in this manner and heating the resin to a temperature of 880° C. or higher and 880° C. or lower. Further, after this, finishing processing such as surface polishing may be performed as necessary.

Next, examples of the present invention will be described.

Of course, the present invention is not limited to this embodiment.

Example 1 Aluminum roller (50ai*) The surface was roughened by sandblasting. PFA resin (MP-
10-2, Mitsui Flo4 Chemical Co., Ltd., trade name) powder and fluorocarbon powder (made from petroleum coke) were mixed at a weight ratio of 100:5, and the mixed powder was stirred and electrostatically coated. The coating was applied to the roller surface to a thickness of 40 μm according to the method, and the coating was melted and baked at the temperature shown in Table 1 for 20 minutes. Furthermore, roughen the surface of this roller JIB-B-0
The surface was polished to an average roughness of 1 μm (as defined by 601).

This roller was set in the fixing section of a copying machine, and the toner image on the paper was fixed at a roller surface temperature of 180° C., and the occurrence of offset was observed. A case where even a slight offset occurred was expressed as (x), and a case where no offset occurred was expressed as 0.

Furthermore, in order to evaluate the scratch resistance of these rollers, a PPS separation claw was attached to the fixing roller with a load of 200 J'.
1st place, 4-ra surface temperature: 90℃±5℃ Rotation speed: 300
Continuous rotation for 500 hours at iuc/sec,
The depth of scratches on the roller surface caused by nails was measured.

These results are shown in Table 1.

It can be seen that when carbon fluoride is added to PFA in this way, the baking temperature is required to be 830 to 880°C.

Example 2 After roughening the surface of an aluminum roller by sandblasting, a tetrafluoroethylene resin primer (
EK-1908GY (manufactured by Daikin Industries, Ltd.) was applied and dried. PFA resin and fluorocarbon powder were mixed on this surface in the proportions shown in Table 2, and the stirred mixture was coated on the roller surface to a thickness of 40μ using a powder electrostatic coating method. It was melted and fired. Furthermore, this roller was finished to a surface roughness of 1μ.

These rollers were evaluated in the same manner as in Example 1.

Table 2 As shown above, it can be seen that the appropriate amount of fluorinated carbon to be added to PFA is 2 to 2096 in terms of weight ratio.

Claims (2)

[Claims] (1) A mixed powder of tetrafluoroethylene-perfluoroalkoxyethylene copolymer fluorinated carphone was coated on the outer surface of Gold 140-La by powder electrostatic coating, and this was further coated with 8
A method for manufacturing a fixing roller, characterized by baking at a temperature of 80°C or higher and 880°C or lower. (2) The mixing ratio of tetrafluoroethylene-perfluoroalkoxyethylene copolymer and fluorocarbon is 100:2
2. The method of manufacturing a fixing roller according to claim 1, wherein the weight ratio is 100:20.