JPH08278713A - Fixing device - Google Patents

Abstract

PURPOSE: To stably drive a film for fixing by arranging a heating body on one surface side of the film for fixing, bringing an image carrier into contact with the other surface side, and making the film for fixing giving the image carrier heat energy through the film for fixing include the specified weight of diamond fine powder. CONSTITUTION: The heating body 14 is arranged on one surface side of the film 1 for fixing, the image carrier is brought into contact with the other surface side, and the film 1 of the fixing device giving the image carrier the heat energy through the film include the 0.01 to 0.5wt.% of the diamond fine powder. Thus, abrasion resistance can be improved without damaging the mechanical characteristics of the film 1, and the film can be stably driven. The diamond powder whose average grain diameter is <=100nm, especially <=50nm and >=0.1nm is preferable. When the average grain diameter exceeds 100nm, the diamond powder easily falls in the case of sliding on a heater 14, and when the average grain diameter is <0.1nm, uniform dispersion can not be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device of a type in which heat energy is applied to an image carrier through a film, and more specifically, the present invention relates to a copying machine, a laser beam printer, a facsimile, a microfilm reader. In an image forming apparatus such as a printer, an image display (display) device, a recording machine, etc., a recording material using a toner made of a heat-meltable resin by an appropriate image forming process means such as electrophotography, electrostatic recording, magnetic recording, etc. (Electrofax sheet, electrostatic recording sheet, transfer material sheet, printing paper, etc.)
An unfixed toner image corresponding to the target image information is formed and carried on the surface of the recording medium by a direct method or an indirect (transfer) method, and the unfixed toner image is permanently fixed on the recording material surface carrying the image. It can be utilized as an image fixing device for heat fixing processing.

Further, the present invention is not limited to an image fixing device, but relates to a fixing device which can be widely used as a device for heating an image carrier, such as a device for heating a recording material carrying an image to modify its surface property. Is.

[0003]

2. Description of the Related Art Conventionally, a heating device for a recording material, for example, for heating and fixing an image, includes a heating roller which is maintained at a predetermined temperature, and a pressure roller which has an elastic layer and is in pressure contact with the heating roller. Therefore, a roller system is widely used in which a recording material is nipped and conveyed and heated. U.S. Pat. No. 3,578,797
A belt fixing method is also known as an image fixing means as disclosed in the specification. This is because (1) the toner image is brought into contact with the heating element web and heated to its melting point to melt, and (2)
After melting, cool the toner to a relatively high viscosity,
(3) It is a method of fixing without causing offset by going through a process of peeling from the heating body web in a state where the tendency of toner adhesion is weakened.

There are also a flash fixing method and an oven fixing method. Recently, a heating device (film heating system) having a constitution including a fixedly supported heating body, a film opposed to and in contact with the heating body, and a pressure member for heating a recording material through the film has been devised. . The system apparatus disclosed in Japanese Patent Laid-Open No. 63-313182 proposed by the present applicant belongs to this, and an unfixed toner image is formed through a thin heat-resistant film (sheet) that is brought into pressure contact with a fixed heating element. It is a heating means / apparatus which is based on the fact that the film and the recording material are separated from each other after heat energy is applied to the film to soften / melt it, or the film and the recording material are separated from each other after the toner is cooled / solidified. However, the conventional heat roller system as described above, the belt fixing system described in US Pat. No. 3,578,797, and other systems have the following problems.

In the heat roller method, (1) it takes a considerable amount of time to rise to a predetermined temperature, and during that time, the image forming operation is prohibited. That is, there is a so-called wait time. (2) A large amount of electric power is required because a heat capacity is required. (3) A heat-resistant special bearing is required because the roller temperature is high in the rotating roller. (4) The roller is in direct contact with the hands, which is dangerous and requires a protective member. (5) Depending on the fixing temperature and the curvature of the roller, the recording material is easily wound around the roller and jamming of the recording material is easily seen. (6) Since the temperature of the fixing point for fixing the toner on the recording material is equal to the temperature of the separation point of the recording material and the heat roller, a high temperature offset depending on the separation temperature is likely to occur, and an image depending on the separation temperature is generated. The degree of gloss cannot be controlled.

In the flash and oven fixing methods, (1) the device becomes large. (2) There is a risk of ignition if the image clarity is reduced or the recording paper remains in the fixing device. In the belt fixing method, even in this method, there are problems such as the wait time and the large power consumption similar to the above items (1) and (2) of the heat roller method. The film heating method has the following advantages: (1) Small heat capacity and low power consumption. (2) Offset can be prevented because the fixing point and the separation point can be set separately. However, in the case of a belt fixing method or a film heating method, the belt film is heated to a high temperature for a long time and slides while being pressed against the surface of the heating body by a pressure roll. Therefore, the heating body contact surface of the film (hereinafter referred to as the film back surface) may be worn during long-term use.

The present inventor conducted the following experiment in order to examine these problems. In this experiment, a polyimide film having a thickness of 20 μm was used as a fixing film, and a 6 μm P. F. A. Perimeter coated with 100 mm
An endless fixing film 1 having a width of 220 mm was mounted on the fixing device shown in FIG. Pressure roller 13 is φ20
Then, an elastic layer made of silicon rubber was formed on the outer circumference of the cored bar, and a PFA tube was coated on the elastic layer and the hardness was about 55 degrees (Asuka-C). The total pressure was 7 kg and the film was pressed against the film 1. When the heating body 14 was heated to about 200 ° C. and the fixing film 1 was driven at 50 mm / sec, the fixing film 1 began to be partially scraped in 100 hours, and the heating body 14 was heated.
And the film 1 has started to accumulate near the contact portion of the film 1 and on the drive roller 11. When the durability test was continued further as it was, shavings of the film 1 were accumulated between the fixing film 1 and the heating body 14 and the heat supply from the heating body 14 to the surface of the fixing film 1 was hindered at that portion. Therefore, fixing failure occurred in the corresponding portion of the recording material. Further, the shavings of the film 1 may be accumulated on the surface of the driving roll, and the driving of the fixing film 1 may become unstable. The following conventional measures have been taken to prevent the back surface of these films from being scraped.

1) Heat-resistant grease is interposed between the heating members 14 on the rear surface of the fixing film 1. 2) Disperse a lubricant such as PTFE in the fixing film 1. However, 1) the back surface of the fixing film 1 and the heating element 14
The use of heat resistant grease between them has the drawback that the grease gradually disappears or deteriorates when the fixing device is used for a long period of time. Further, when a large amount of grease is intervened in the initial stage in order to prevent the above defects, the fixing film 1
Drive becomes unstable, and grease is used for fixing film 1
There was a problem such as getting around to the surface of the. In the fixing device shown in FIG. 1, the allowable heat resistant grease is 50 m.
Although the amount was g to 250 mg, even when 250 mg of grease was used, the fixing film began to be scraped in the 200-hour durability test.

2) When a lubricant such as PTFE is dispersed in the base film, at least 1% or more, preferably 2% or more of the lubricant is mixed in the fixing film resin in order to prevent the base film from being scraped. There was a need.
However, when 2% or more of the lubricant is mixed in the fixing film resin, the tensile strength of the fixing film is lowered and the mechanical strength such as brittleness is lowered. In addition, there is a method using an inorganic filler, but most of them have an average particle diameter of 0.1 μm to several μm,
When these were dispersed in the fixing base film, in addition to the above-mentioned drawbacks, irregularities due to these particles were generated on the surface of the fixing film. In this case, the friction coefficient was significantly reduced, and the driving of the fixing film became unstable.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel fixing device which solves the above-mentioned problems with the conventional fixing device.

[0011]

This object is achieved by the following means. That is, according to the present invention, a heating body is arranged on one side of the fixing film, and an image carrier is brought into close contact with the other side of the fixing film, and thermal energy is applied to the image carrier via the fixing film. And a fixing device comprising a heat-resistant resin and containing 0.01 to 0.5% by weight of diamond powder. Yes, the heating element makes linear contact with the fixing film,
The diamond powder includes that the average particle size is 100 nm or less.

[0012]

In the fixing device, a heating member is arranged on one side of the fixing film, and the image carrier is closely attached to the other side, and heat energy is applied to the image carrier via the fixing film. By containing 0.01 to 0.5% by weight of diamond fine powder in the film, the abrasion resistance can be greatly improved without impairing the mechanical characteristics of the fixing film, and the fixing film can be stable for a long period of time. It becomes possible to drive. Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic side view showing an example of the fixing device of the present invention, and FIG. 2 is a sectional view showing an example of a fixing film used in the fixing device of the present invention. The fixing device of the present invention is
For example, as shown in FIG. 1, an endless fixing film 1
A driving roller 11 for rotating and driving the fixing film 1, a tension roller 12 for applying an appropriate tension to the fixing film 1, and a pressure roller 13 for pressing an image carrier described later through the fixing film 1. A heating body 14 is arranged on one surface side of the fixing film 1 which is rotationally driven by the rollers 11, 12, and 13 via a heat insulating holder 15 fixedly held by a stay 16. On the other side of the fixing film 1, an image carrier made of a transfer paper 23 on which a toner image 22 is formed is conveyed by a conveyor belt 21 so as to be in close contact with the pressure roller 13. As a result, heat energy from the heating body 14 is applied to the image carrier through the fixing film 1. The endless fixing film 1 is driven in the direction of arrow A by a drive mechanism (not shown),
The pressure roller 13 is adapted to rotate in the direction of the arrow, and the fixing film 1 is rotationally driven at a speed of 20 to 300 mm / min.

Further, the tension roller 12 is applied in the direction of arrow B in order to apply tension to the endless fixing film.
A tensile force of 5 to 5.0 kg is applied. The heating element 14 is, for example, a linear heating element arranged in parallel on a ceramic substrate, and is covered with a protective layer of glass, polyimide, heat resistant resin such as PTFE, or the like. The temperature of the heating element 14 is detected by the temperature detecting element 17, and the supply power is controlled by a control circuit (not shown) to obtain a temperature of 150 to 25.
Set to 0 ° C. The roller arrangement is not limited to that described above, and the form of the fixing device can be appropriately selected. Next, the fixing film used in the fixing device of the present invention will be described. As shown in FIG. 2, the fixing film is formed by laminating a base film layer 2 made of a heat-resistant resin containing diamond powder 5 and a release layer 4 via a primer layer 3.

The heat resistant resin usable as the base film layer 2 includes polyimide, polyetherimide, polyetheretherketone, PES, polyamideimide, PPS, PFA and the like. Furthermore, examples of the resin used as the release layer 4 include fluororesins such as PTFE and PFA, silicon resins, and silicone rubber. It is preferable that the release layer 4 of the base film layer 2 has conductivity because the offset can be further reduced. If the diamond powder is less than 0.01% by weight, the effect of improving the abrasion resistance of the film is insufficient, and the fixing film cannot be stably driven for a long time, which is not preferable.
If it exceeds 0.5% by weight, physical properties such as mechanical strength of the film are deteriorated, which is not preferable.

The average particle size of diamond powder is 100.
nm or less, particularly 50 nm or less and 0.1 nm or more are preferable. If the average particle size of the diamond powder exceeds 100 nm, there is a problem that it tends to come off during sliding with the heater, which is not preferable, and if it is less than 0.1 nm, uniform dispersion cannot be obtained, which is not preferable. Diamond powder has extremely good dispersibility, does not require a dispersion aid, is harder than the glass reinforcement layer, has high thermal conductivity, and has a good wear resistance improving effect even when added in a small amount. It is extremely preferable as a film additive. The diamond powder 5 and the resin of the base film layer 2 can be mixed by any known means depending on the kind of the resin.

[0016]

EXAMPLES The present invention will be further described below based on examples. (First Embodiment) FIG. 2 is a sectional view of a fixing film according to the present invention, and 2 is a polyimide resin having a thickness of 20 .mu.m.
m fixing base film, 3 is a primer layer, 4 is P
It is a release layer made of FA (perfluoroethylene perfluoroalkyl copolymer). 5 is a diamond fine powder according to the present invention, having an average particle size of about 0.5 nm,
0.0 for polyimide, which is the base film for fixing
3 wt% was dispersed. Perimeter of 10mm with the above film configuration
Fig. 1 shows an endless fixing film with a width of 220mm.
The fixing device shown in 1 was constructed and incorporated in an image forming apparatus for evaluation. In FIG. 1, 11 is a drive roller, which has a core metal covered with silicon rubber and has a diameter of about 16 m.
m. This drive roller drives the fixing film base in the direction of arrow A by a drive mechanism (not shown) at a speed of 50 mm by the frictional force on the surface of the drive roller. A tension roller 12 is pulled by 2 kg in the direction of arrow B to give tension to the endless fixing film. A pressure roller 13 is formed by forming an elastic layer of silicon rubber on the cored bar, and further coating a PFA tube having a thickness of 50 μm on the elastic layer. The pressure roller 13 has a diameter of about 20 mm and a hardness of about 55 degrees (Asuka-C).
It is pressed against the film with a total pressure of 8 kg, and is rotated by the fixing film. 14 is a heater having a thickness of about 1 m
A heat generating layer and a protective layer were formed on the alumina ceramic substrate of m, and heat was generated by energizing. This heater is held by a heat insulating holder 15 fixed on a metal stay 16 and set to about 200 ° C. by controlling the electric power supplied by a control circuit (not shown) from the temperature detected by the temperature detecting element 17. did.

The evaluation results are shown in Table 1.

[0018]

[Table 1] As a comparative example, a conventional base film containing no lubricant and a PTF having an average particle size of about 0.2 μm as a lubricant are used.
E (tetrafluoroethylene) powder 1 wt%, 3 wt%
1 of mixed powder and alumina powder with an average particle size of about 1 μm
wt% and 3 wt% are respectively dispersed in the fixing base film. Here * 1 in Table 1
In the case of 250 hours, the fixing film was stretched after 250 hours of durability, so that the fixing film meandered, became uncontrollable, and was interrupted. In * 2 in Table 1, the surface of the fixing base film was scraped, and the frictional resistance with the drive roll was lowered too much, resulting in unstable driving and interruption.

As is clear from this evaluation, it is clear that by dispersing the fine diamond powder in the fixing base film, the performance was significantly improved against abrasion of the fixing film. Characteristically, the diamond fine powder exerts the above-mentioned effect with an extremely small amount with respect to other fillers. Therefore, it became possible to improve abrasion resistance without impairing other physical properties of the polyimide base film. Further, when the filler such as alumina begins to fall off from the fixing base film by the durability test, it becomes abrasive powder itself, and the fixing film is rapidly worn from a certain point, whereas the diamond used in the present invention. Since the powder has a very small particle diameter, it is difficult to fall off, and the diamond powder having a small particle diameter acts as a sliding lubricant, so that the fixing film can be stably driven for a long period of time.

[0020]

EFFECT OF THE INVENTION A heating device is arranged on one side of a fixing film, and an image carrier is brought into close contact with the other side of the fixing film, and a fixing device for applying thermal energy to the image carrier through the fixing film. By containing 0.01 to 0.5% by weight of diamond fine powder in the fixing film, a stable fixing film drive for a long period of time was obtained.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an example of a fixing device of the present invention.

FIG. 2 is a sectional view showing an example of a fixing film used in the fixing device of the present invention.

[Explanation of symbols]

 1 Fixing Film 2 Base Film 3 Primer Layer 4 Release Layer 5 Diamond Fine Powder 11 Drive Roller 12 Tension Roller 13 Pressure Roller 14 Heating Body (Heater) 15 Holder 16 Stay 17 Temperature Detection Element 18 Entrance Guide 19 Paper Ejection Roll 20 Paper ejection guide 21 Conveyor belt 22 Toner image 23 Transfer paper

Claims (3)

[Claims] 1. A heating body is arranged on one side of a fixing film, and an image carrier is brought into close contact with the other side of the fixing film, and thermal energy is applied to the image carrier via the fixing film. The fixing film is made of a heat-resistant resin, and is 0.01 to 0.5.
A fixing device comprising a diamond powder in a weight percentage. 2. The fixing device according to claim 1, wherein the heating member linearly contacts the fixing film. 3. The diamond powder has an average particle size of 100 n.
The fixing device according to claim 1, wherein the fixing device has a thickness of m or less.