JPH03220581A - Fusing device - Google Patents

Abstract

PURPOSE:To improve the wear resistance of the surface of a fixing roller by forming a diamond-like thin film on the surface of the fixing roller and providing an oil coating means coating the surface of the fixing roller with silicone oil. CONSTITUTION:The fixing roller 1 is constituted such that a cylindrical core metal 1B is provided with a non-crystalline diamond-like thin film 1A on its surface, and the diamond-like thin film is coated with the silicone oil by this oil coating means 4. As for the oil coating means 4, an oil supplying member 4A in contact with the surface of the fixing roller 1 and an oil coating blade 13 in contact with the surface on the downstream side of the rotary direction of fixing roller 1 are provided on the bottom wall of an oil pool 4C containing the silicone oil 4B. The silicone oil 4B which is stored in the coil pool 4C of the oil coating means 4 is provided on the surface of the fixing roller 1 through the oil supplying member 4A and uniformly spread by the coating blade 13, and the diamond-like thin film 1A on the surface of the fixing roller 1 is uniformly coated. Thus, the wear resistance of the fixing roller can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION No. 11 The present invention relates to a fixing device used for fixing an image formed on a recording material in an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus.

Ai Kanriku 1 Forms an image on a sheet-like recording material using an electrostatic recording method,
Electrostatic recording devices that thermally fix this image onto a recording material using a fixing device equipped with a fixing roller consisting of a heating roller are widely used.

FIG. 4 shows a conventional fixing device in the above-mentioned electrostatic recording device.

In FIG. 4, reference numeral 5 denotes a fixing roller, and the fixing device includes a fixing roller 5 and a pressure roller 6. The fixing roller 5 applies heat to the image on the recording material 10, and the pressure roller 6
By applying pressure to the image, the toner T constituting the image is heated and melted, and the image is fixed on the recording material 10.

The fixing roller 5 is made of a cylindrical core made of aluminum or the like and coated with, for example, a Teflon (trade name) layer for offset prevention, and has a heater 11 disposed inside to function as a heating roller.

The pressure roller 6 has a heat-resistant sponge layer such as silicone rubber coated on a core metal 12 made of iron or the like, and a silicone rubber layer is coated on top of the silicone rubber layer, thereby providing a suitable elasticity as a whole. It is recommended that you have it. The pressure roller 6 is in pressure contact with the fixing roller 5 with an appropriate nip width.

An image is formed at an image forming portion (not shown) of the electrostatic recording device, and the recording material 10 on which the image is transferred is led to the fixing device through the conveyance path of the electrostatic recording device, and is guided to the fixing device by its rollers 5.6.
During this passage, the toner T constituting the image is heated and melted by the heat applied by the fixing roller 5 and the pressure applied by the pressure roller 6, thereby forming the image. After the six images have been fixed and fixed on the recording material 10, the recording material 10 is then discharged to the outside through the discharge path of the electrostatic recording device.

In such a fixing device, the surface temperature of the fixing roller 5 is detected by a temperature detection means (not shown) such as a thermistor, and the temperature is maintained at a substantially constant level, and the image on the recording material 10 is kept in direct contact with the fixing roller 5. The image is fed between the fixing roller 5 and the pressure roller 6 with the image on the fixing roller 5 side so that they are in contact with each other.

For this reason, when fixing an image, the toner T heated, softened, and increased in viscosity adheres to the surface of the fixing roller 5 and contaminates (offsets) it. There is an unavoidable possibility that the recording material 10 being fed will be contaminated.

In order to avoid such a situation, a cleaning means such as a rod-shaped felt material or a web has been conventionally provided to clean the fixing roller 5 by pressing it against the fixing roller 5, or applying silicone oil to the surface of the fixing roller 5. Various proposals have been made, such as cleaning by applying a mold release agent such as.

In the fixing device shown in FIG. 4, an opening extending in the axial direction of the fixing roller 5 is formed in the casing 9 of the device at a position near the top of the fixing roller 5, and a heat-resistant felt is impregnated with silicone oil in the opening. A rod-shaped oil applying/cleaning member made of a cleaning material 8 supported by a holder 7 is attached, and is brought into contact with the fixing roller 5.

However,
The above-mentioned conventional fixing device uses an expensive fluororesin on the surface of the fixing roller 5, which has the disadvantage of increasing the cost of the fixing roller 5.

Furthermore, fluororesin is a material with high strength and high wear resistance among resin materials, but when used on the surface of the fixing roller 5, the separation claws, thermoswitches, etc. arranged around the surface of the fixing roller 5, Because it comes into contact with components such as thermistors,
Long-term use will also cause wear and tear. For this reason, there is a problem in that the image is disturbed due to unevenness due to wear of the fluororesin layer on the surface of the fixing roller 5 and dirt on the uneven portion.

As a countermeasure to the problem caused by wear of the fluororesin layer on the surface of the fixing roller 5, it is possible to make the fluororesin layer thicker, but since fluororesin has low thermal conductivity, if it is made too thick, the internal heater 11 Heat conduction from the
Since problems such as poor fixing occur, there are limits to the method of increasing the thickness of the fluororesin layer, and it is not a fundamental solution.

Furthermore, in the conventional fixing device described above, since the volume resistivity of the fluororesin is high, the fixing roller 5 is charged during use, and the toner T forming the image is offset to the fixing roller 5 due to the electric field caused by the charging. There is also the problem of a phenomenon called charging offset.

Therefore, an object of the present invention is to improve the abrasion resistance of the surface of the fixing roller and to prevent the charging offset of the fixing roller so that the fixing roller can be properly fixed without causing image disturbance. To provide a fixing device that does not become expensive.

The above objects are achieved by the fixing device according to the present invention. In summary, the present invention provides a fixing device that fixes the image onto the recording material by inserting a recording material onto which an image has been transferred between a fixing roller and a pressure roller, and heating and pressing the image. In the fixing device, a diamond-shaped thin film is formed on the surface of the fixing roller, and an oil application means is provided for applying silicone oil to the surface of the fixing roller. The diamond-like thin film is an amorphous diamond layer intermediate between graphite and diamond, and the diamond-like thin film can also be formed on the surface of the fixing roller via an elastic layer.

1L case Examples of the present invention will be described in detail below.

FIG. 1 is a configuration diagram showing an embodiment of a fixing device of the present invention.

As shown in FIG. 1, the fixing device of the present invention includes a fixing roller l, a pressure roller 2, and an oil application means 4, as in the conventional case.
Basically, a heater 3 is provided inside the fixing roller l. The pressure roller 2 includes a core metal 2B coated with a silicone rubber layer 2A.

A feature of the fixing device of the present invention is that the fixing roller l has a structure in which an amorphous diamond-shaped thin film IA is provided on the surface of an aluminum cylindrical core metal IB. The diamond-shaped thin film IA is formed by a plasma CVD method in which methane (CH4) gas is decomposed by glow discharge.
It is an amorphous diamond layer that is intermediate between graphite and diamond.

The characteristics of this diamond-like thin film are that it has a high hardness of 3000 kg/mrrr on the Vickers scale, and has a heat resistance of about 250°C for fluororesin.
With this thin film, the temperature can be improved up to about 400℃, the coefficient of friction is as low as 0.1, and the thermal conductivity is 5.0X1 higher than that of fluororesin.
0-'caβ/cm-8-deg, this thin film has a
．． The two points are that it is about one digit higher at 0x10'cal/cm-s-deg, and that the material cost is extremely low because CH4 is used.

As long as the thickness of the diamond-like thin film IA provided on the surface of the aluminum cylindrical core metal IB is 0.3 μm or more, the intended effects of the present invention can be fully exhibited. The upper limit of the film thickness is desirably 10 μm or less in consideration of productivity from the film formation rate.

The fixing roller 1 having the diamond-like thin film IA on its surface exhibits excellent hardness and wear resistance, but it lacks the non-adhesive properties of fluororesin.
If this continues, toner adhesion will occur soon. Therefore, in the present invention, a method is used in which silicone oil is applied onto the diamond-shaped thin film 1A by the oil application means 4 to improve the non-adhesiveness of the fixing roller 1.

The reason why silicone oil is used in the above is that the diamond-like thin film LA is composed of carbon (C), and the bonding force of that carbon with silicon (St) in the silicone oil is the reason why the diamond-like thin film LA is composed of carbon (C), and the bonding force of the carbon with silicon (St) in the silicone oil is the reason why the diamond-like thin film LA is composed of carbon (C). Because it is large compared to the force,
When silicone oil is applied, the silicone oil adheres well to the thin film IA and blends in. Therefore, even if it comes into contact with parts such as separation claws, thermoswitches, and thermistors arranged around the surface of the fixing roller 1, the silicone oil will not be removed. Because it is difficult to get wet and uneven coating occurs,
This is because it is possible to form a uniform silicone oil layer on the surface of the fixing roller 1 and provide better mold release properties than when a fluororesin is used on the surface of the fixing roller 1.

Although the fluororesin itself has good mold releasability, it does not have enough mold releasability to prevent toner adhesion such as an offset phenomenon. For this reason, conventional methods have been considered to improve the releasability of the fixing roller surface by applying silicone oil to the surface of the fixing roller, forming an oil film, and utilizing the releasability caused by the splitting of the oil film. is being used. However, when silicone oil is applied on the fluororesin layer on the surface of the fixing roller, microscopically, the silicone oil is repelled by the releasability of the fluororesin, so a uniform film of silicone oil is formed. As a result, a phenomenon occurs in which toner adheres to areas on the surface of the fixing roller where there is no oil film. For this reason, conventionally,
It was not possible to obtain a sufficient release effect by applying oil to the fixing roller.

On the other hand, when the diamond-like thin film IA is formed on the surface of the fixing roller 1 as in the present invention, the fixing roller l
Since a microscopically uniform silicone oil film can be formed on the surface of the fixing roller 1, the release effect of the silicone oil can be sufficiently exerted on the surface of the fixing roller 1. In addition, the amorphous diamond-like thin film lA has a volume resistivity of 1O12
It is as low as about Ωcm, and even if the fixing roller 1 is charged, the charged charge decreases immediately, so offset due to static electricity is less likely to occur.

As described above, the silicone oil is applied to the diamond-like thin film l on the surface of the fixing roller l by the oil application means 4.
Coated on A. The oil application means 4 includes an oil supply member 4A that contacts the surface of the fixing roller 1, and an oil application blade that contacts the downstream surface of the fixing roller 1 in the rotational direction. 13 are provided.

The silicone oil 4B accommodated in the oil reservoir 4C of the oil application means 4 is supplied onto the surface of the fixing roller 1 through the oil supply member 4A, and the application blade 13 uniformly distributes the supplied silicone oil 4B. Spread it out and apply it uniformly onto the diamond-shaped groove film IA on the surface of the fixing roller 1.

The oil supply member 4A is formed of a member that can gradually supply the silicone oil 4B onto the surface of the fixing roller 1 while permeating the silicone oil 4B from the oil reservoir 4C. To give a specific example of the supply member 4A, it is possible to use, for example, a porous PTFE material (BOAFLON manufactured by Sumira Electric Industries, Ltd.) molded into a rectangular parallelepiped.

The application method using the present oil application means 4 is most preferable for use in the present invention because silicone oil can be actively applied onto the surface of the fixing roller 1.

Another type of oil application means that can be used in the present invention is shown in FIG. The oil application means 5 shown in FIG. 2 is of a web cleaner type, and the fixing roller 1
It also serves as a surface cleaning device.

The oil application means 5 includes a web roller 5A that has been pre-impregnated with silicone oil and has wound a web 5D, a take-up roller 5C that winds up the web 5D, and a web 5D that has been unwound from the web roller 5A. Pressing roller 5B pressed onto the diamond-shaped groove film IA on the surface of the roller 1
It consists of The web 5D is pressed by the pressure roller 5B to form a diamond-shaped groove film I on the surface of the fixing roller 1.
While being pressed onto the thin film IA, it travels by winding up with the winding reroller 5A, applying the pre-soaked silicone oil onto the thin film IA, and cleaning the thin film IA.

The results of durability tests conducted on the fixing roller according to the present invention and a conventional fixing roller whose surface is provided with a fluororesin layer will be described.

Conventional fixing rollers are made by coating a cylindrical aluminum core with a primer, dispersing PFA powder, and then sintering to form a fluororesin layer on the core with a thickness of approximately 30 μm. was used. The fixing roller of the present invention has a diamond-like thin film formed on a cylindrical core made of aluminum to a thickness of about 5 μm by a plasma CVD method in which methane gas (CH4) is decomposed by glow discharge. Silicone oil was applied onto the surface of each of the fixing rollers using the same means as the oil application means 4 shown in FIG. As the silicone oil, for example, one having a dimethylpolysiloxane structure (manufactured by Toray Silicone Co., Ltd., 5H200, oil viscosity 10000C3) was used.

As a result, with a conventional fusing port provided with a fluororesin layer, wear can be observed in the areas where the separation claw, thermoswitch, and thermistor come into contact after approximately 10,000 sheets of A4 recording material have been passed through. When approximately 150,000 sheets were passed, the fixed images on the recording material began to become distorted due to abrasion of the surface of the fixing roller 1.

In contrast, with the fixing roller provided with the diamond-like thin film of the present invention, after 300,000 sheets of recording material were passed through, almost no wear could be observed with the naked eye at the points of contact with various parts such as thermoswitches. Also, no toner adhered to the surface of the fixing roller.

As described above, in the fixing device of the present invention, the fixing roller,
It has a structure in which a diamond-like thin film is provided on the surface of the core metal,
Since silicone oil is applied on the thin film, the wear resistance and heat resistance of the fixing roller are improved, the life of the fixing device can be extended at low cost, and the fixing performance is good. .

FIG. 3 is a configuration diagram showing another embodiment of the fixing device of the present invention. In the fixing device of this embodiment, the first point is that an elastic layer IC is provided on the aluminum cylindrical core bar IB of the fixing roller 1, and a diamond-shaped thin film IA is provided thereon.
The other configurations of the 0-piece fixing device, which is different from the fixing device shown in the figure, are basically the same as the fixing device shown in FIG.
In the drawings, the same reference numerals as in FIG. 1 indicate the same members.

The purpose of this embodiment is to further improve the fixing performance compared to the fixing device shown in FIG. 1 without reducing the life of the fixing roller 1. For this reason, an elastic layer IC is provided on the fixing roller l, not only on the pressure roller 2 side, but also on the pressure roller 2 side.
By imparting a certain degree of elasticity to the surface on the side of the fixing roller l, the adhesion at the nip portion N between the fixing roller 1 and the pressure roller 2 is increased, thereby realizing an improvement in fixing performance.

The elastic layer 1C of the fixing roller 1 is made of carbon (C) and silicon (Si).
) It is preferable to use silicone rubber to increase the adhesion between the elastic layer IC and the diamond-shaped thin film IA made of carbon thereon. Also, among silicone rubbers, highly cross-linked rubbers are preferred because of their low leakage of silicone oil. The thickness of the elastic layer IC is desirably about 10 μm to 50 μm, considering both heat conduction and fixing properties.

The diamond-like thin film IA may be formed on the elastic layer IC by the plasma CVD method in which methane gas (CH4) is decomposed by glow discharge in the same manner as in the previous embodiment. Silicone oil is similarly applied onto the diamond-shaped groove film LA by the oil application means 4 to impart non-adhesive properties.

The results of a comparative test of fixing properties will be described between the case where the fixing roller according to this embodiment is used and the case where the fixing roller according to the previous embodiment shown in FIG. 1 is used.

The fixing roller of this example has an elastic layer made of silicone rubber with a thickness of 30 um provided on a cylindrical core made of aluminum via a brimer, and a diamond-like thin film formed on the elastic layer with a thickness of 3 um. Using. The fixing roller used in the previous example was made by forming a diamond-shaped thin film with a thickness of 101 m on a cylindrical core metal made of aluminum.

As a result, it was found that when the pressing force between the fixing roller and the pressure roller is equal, the fixing performance of a solid black image is improved by about 5% with the fixing roller provided with the elastic layer of this example. Ta. The fixability here is the rate of density decrease when a solid black image fixed on a recording material is rubbed back and forth 5 times with Sylbon C (product name) at a pressure of Q, 4 g/mrrr. It is expressed as a linear equation.

Fixability (%) = (Density before rubbing - Density after rubbing) / Density before rubbing xlOO As described above, in the image fixing device of this embodiment, after providing an elastic layer on the core of the fixing roller, A diamond-like thin film is provided on the fuser roller, and silicone oil is applied to the thin film, improving the abrasion resistance and heat resistance of the fusing roller.
Not only can the life of the fixing device be extended at low cost, but also the fixing performance is significantly improved.

4 Glossary Emperor 1 As explained above, in the fixing device of the present invention, the fixing roller has a structure in which a diamond-shaped thin film is formed on the core metal with or without an elastic layer, and silicone is coated on the surface of the thin film. Since the oil is applied, the abrasion resistance and heat resistance of the fixing roller are improved, the life of the fixing device can be extended at low cost, and the fixing performance is good.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a fixing device of the present invention. FIG. 2 is an explanatory diagram showing another example of the oil application means used in the fixing device of FIG. 1. FIG. 3 is a configuration diagram showing another embodiment of the fixing device of the present invention. FIG. 4 is a configuration diagram showing a conventional fixing device. 1: Fixing roller 1A: Diamond-like thin film 1B: Core metal IC 2 Elastic layer 2: Pressure roller 4.5 Oil application means

Claims (1)

[Scope of Claims] 1) Fixing that fixes the image onto the recording material by inserting a recording material onto which an image has been transferred between a fixing roller and a pressure roller and heating and pressurizing the image. What is claimed is: 1. A fixing device comprising: an oil application means for forming a diamond-shaped thin film on the surface of the fixing roller and applying silicone oil to the surface of the fixing roller. 2) The fixing device according to claim 1, wherein the diamond-like thin film is an amorphous diamond layer in an intermediate state between graphite and diamond. 3) The fixing device according to claim 1 or 2, wherein the diamond-like thin film is formed on the surface of the fixing roller via an elastic layer.