JPS60205561A - Fixing roller and fixing device having it - Google Patents

Abstract

PURPOSE:To obtain a roller superior in durability and abrasion resistance by forming a layer of a mixture of fluororubber and fluororesin, strongly bonding the lower rubber layer with the upper resin layer, and increasing thickness of the surface resin. CONSTITUTION:The rubber layer 2b of a roller A is thermally vulcanized and fixed to a metal substrate 3 in a state of rubber elasticity. A mixture of fluororubber and fluororesin is applied to the rubber layer 2b in 20m thickness with a coating means, and dried at room temp. or in a heated state. At that time, water repellency of the fluororesin appears not so much on the surface of this mixture. This surface is coated with a PFA resin in an emulsion state in a thickness of 10m. At the next time of baking, in a mixture between the layer 2b and the PFA resin layer 1, the fluororesin floats up on the side of the layer 1 by the result of Brownian movement and at the same time cross-linking of the fluororubber component proceeds. After this process, the final heat treatment is executed at 350 deg.C for 30min to melt the surface PFA resin layer to allow it to adhere to the lower layer perfectly and smooth the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applied to image forming apparatuses such as copying machines, printing machines, printers, and multifunction recording devices in general, and is applied to fixing rollers used for purposes such as heating, pressurization, heating and pressurization, etc. and a fixing device having the same.

Conventionally, in roller fixing devices, the surface layer of the fixing roller has
RTV silicone rubber and Teflon (product name: DuPont)
In some cases, a release agent such as silicone oil is further applied to prevent off-set. Fixing rollers whose surfaces are coated with RTV silicone rubber generally do not need to be coated with a release agent, have a simple device, and have good fixing properties due to the elasticity of the silicone rubber, but the release properties change over time. (worsening)
severe, very short-lived, and frequent.

I had to replace the rollers. Also, if you try to maintain mold release properties by applying a mold release agent such as silicone oil, the silicone rubber will swell with the silicone oil.
The physical strength deteriorates and the rollers must be replaced frequently. In addition, the surface of the fixing roller is coated with tetrafluoroethylene-fluoroalkoxyethylene copolymer resin (hereinafter referred to as PF).
A) and polytetrafluoroethylene resin [hereinafter P
A roller coated with a fluororesin such as TFE has higher strength than the above-mentioned silicone rubber, and has good mold releasability when coated with silicone oil.

However, since the roller has no elasticity, its fixing performance is poorer than that of the silicone rubber roller, and when fixing the toner image on the toner image support material, the effect of crushing the image is large.
It has the drawback of reducing image quality. Furthermore, if the roller has an object such as a cleaning plate in contact with it, and if hard dust adheres to the roller and enters the amount of contact between the roller and the roller, there is no elasticity, so there is no place for the force to escape, and scratches are likely to occur.

The above difference in fixing performance is due to the fact that when using an elastic material such as silicone rubber, the shape of the fixing roller follows the unevenness of the support material and the unevenness of the toner image on the support material, resulting in uniform contact throughout. It is considered that the fixing properties are good.

However, in the case of a rigid body such as Teflon (trade name: DuPont), due to the unevenness of the support material and toner image, the convex portions make strong contact with the roller, and the concave portions contact the roller only unstablely. It is thought that the establishment of the fourth part will be very slow. Experimental results show that to completely fix the same toner image, silicone rubber requires 20 to 50 degrees Celsius more than Teflon.
It is known that this can be done at low temperatures.

Further, JP-A-48-851515151 discloses a fixing roller made of a mixture of ethylene resin powder and raw silicone rubber, but in this case, silicone and Teflon are not compatible, resulting in poor dispersibility and poor adhesion. There are many problems such as the strength is very low, and when a release agent such as silicone oil is applied, the silicone rubber swells with the oil, resulting in a very large decrease in physical strength.

Furthermore, as described in JP-A No. 58-5770, a rubber layer is provided on the outer periphery of the fixing roller, and a mixture of fluororubber and fluororesin is applied to the surface of the rubber layer to improve the elasticity of the rubber layer. A fixing roller that has the mold release stability of fluororesin has been proposed. In the case of this type of fixing roller, the release property is obtained by the presence of a large amount of fluororesin on the surface layer of the fixing roller, but this fluororesin layer is generally made of a mixture of fluororubber and fluororesin at a temperature of 260°C to 350°C. In this case, the thickness of the surface fluororesin layer is at most 2
Since the thickness is only ~3 ILm, it is difficult to maintain the release layer for a long period of time because the support material passing through the fixing roller is worn out, and the separating claw, cleaning member, etc. are worn out and displaced by objects that come into contact with it.

Furthermore, if the thickness of the fluororesin layer is made to be more than 2 to 3 times the thickness mentioned above, the firing conditions will need to be, for example, 400°C or higher and the firing time will be over 1 hour, resulting in significant deterioration of the underlying rubber layer. There are disadvantages such as the complexity of the process. Moreover, even in such a case, the thickness of the fluororesin layer is only about 5 gm at most.

The present invention provides a fixing device equipped with a fixing rotating body that solves the above-mentioned conventional drawbacks and exhibits a new and improved fixing effect.

Another object of the present invention is to provide a fixing device that has good #shape properties, fixing properties, and strength over a long period of time.

FIG. 1 shows a sectional view of a fixing roller A according to a first embodiment of the present invention. have,
A layer 2a made of a mixture of fluororubber and fluororesin is applied onto the rubber layer 2b.

A fluororesin layer 1 is coated thereon.

This fixing roller A is obtained as follows.

The rubber layer 2b of the roller A is fixed to the metal substrate 3 in a state in which it has obtained general rubber elasticity by undergoing thermal vulcanization such as secondary vulcanization and secondary vulcanization.

A mixture of fluororubber and fluororesin (for example, fluororubber water-based paint: Daiel GL213, manufactured by Daikin) is applied to the rubber layer 2b to a thickness of 20 mm using a spray gun or other application means.
It is applied onto the surface and dried at room temperature or heated by an infrared heater. Thereafter, it is dried with hot air at a temperature of 150°C. At this time, on the surface of the mixture of fluororesin and fluororubber, the water repellency of the fluororesin is not very visible.
On top of this, PFA4114 resin in an emulsion state is applied to a thickness of 10 wells. After this, the first firing was carried out at 260°C for 1 time.
At this time, the mixture of fluororesin and fluororubber applied between the comb layer 2b and the PFA resin layer 1 causes the fluororesin to come out on the PFA resin side L side due to the Brownian movement of the fluororesin, and at the same time, the fluorine resin Crosslinking of the rubber component progresses. Furthermore, this heat treatment can prevent depolymerization of the lower rubber layer 2b.

Also, the fluororesin that has come out on the PFA resin layer 1 side is PFA.
It blends well with resin and increases adhesive strength.

After this process, a final firing is performed at 350° C. for 30 minutes to melt the PFA resin layer on the surface and make it completely adhered and smooth to the surface. Note that the PFA resin layer may be coated in a PFA resin powder state and electrostatically coated.

Furthermore, when a super heat-resistant fluororubber or silicone rubber that does not deteriorate even at high temperatures of 300° C. or higher is used as the lower rubber layer, it is also possible to immediately perform the final firing step without going through the first firing.

The fixing roller thus obtained has a release layer of fluororesin with a thickness of 100 mm or more on the surface layer, and the elasticity of the lower rubber layer 1 is not lost in the fluororesin layer with a thickness of 10 mm or more, so it is elastic. It also serves as a fixing roller.

In FIG. 2, the fixing roller A of the embodiment of irgJ is used together with the heating roller A' in contact with the toner image. FIG. 2 shows an example of a fixing device used in a recording device, in which a heating roller includes a metallic base 3, a primer (not shown), and an elastic rubber layer 2.
b. For the mixed layer 2a and the fluororesin layer, those described above were used. Here, the fluororesin layer uses PFA resin.

Add,! ! ) The roller is provided with a heater 4 inside a cylindrical base 3, and a toner image T is recorded by a detection member 6 (contact type in this example) for detecting the surface temperature of the roller and a temperature control means 5. The temperature is maintained at a temperature (for example, 180° C. to 200° C.) necessary for fixing to paper P as a material.

The pressure roller B is pressed against the heating roller A by a pressure means (not shown).
The sheet P is pressed against the heating roller A' and conveyed while being held therebetween.

The pressure roller B has a heat-resistant elastic layer 17, such as a silicone rubber layer, on a metal cylindrical core 18.

7 is a cleaning web impregnated with a release liquid such as silicone oil or fluorine oil;
It is moved intermittently by the pressure roller 10 or at a relative speed to the heating roller. By this movement, the surface of the heating roller A' is cleaned of offset toner and a release liquid for preventing offset is supplied.

Reference numeral 12 denotes a conveyor belt, which guides the paper P on which a toner image T has been formed on one side by a predetermined image forming means, to the guide plate 11 and the pressure contact portion between the heating roller A' and the pressure roller B; 13, a heating roller; A separating claw 14 separates the paper P from the pressure roller B, and is in contact with each roller surface.

15 and 16 are a pair of discharge rollers for discharging or sending the paper to other parts. Each arrow in the figure indicates the direction of rotation or movement of each member.

As mentioned above, the heating roller A' is made by imparting rubber properties to the rubber layer 2b, and then placing the mixture 2b of fluorine rubber and fluororesin on the rubber layer 2 as a primer for the fluororesin layer on the surface layer. Since the rubber layer 2 is coated with a fluororesin layer having good mold releasability to a sufficient thickness and to the extent that elasticity is not lost, the rubber layer 2 has appropriate strength and elasticity.

Therefore, the toner image is heat-fixed onto the paper P as an image with good image quality and good fixability in detail. Moreover, at that time, offset of the toner image toward the heating roller can be largely prevented.

Therefore, in a mold using the web 7 as in this example, consumption of the web as a cleaning member can be reduced, and a mold release liquid can be supplied to prevent offset.

At the same time, the heating roller itself is l! Since the Ill type layer has a sufficient thickness, it can withstand wear of the surface layer due to long-term use, and can be put into practical use.

Table 1 shows that the heating roller A' is directly coated with PTFE on the metallic substrate.
, coated with fluororesin such as PFA, FEP, etc.
A mixture of fluororubber and fluororesin is coated on the rubber layer and baked at 300°C for 30 minutes to bring out the fluororesin on one surface layer, and another to which the above-mentioned present invention is applied. This figure shows the state of wear of the fluororesin layer on the surface of the fluororesin layer.

The results shown in Table 1 are based on the fixing device configured as shown in FIG.
diameter is 40cm, recording paper conveyance speed is 210mg18ec,
This is the state when 30 sheets of A4 paper are passed per minute with horizontal feed, and a total of 50,000 sheets are passed.

On the other hand, in a heating roller in which a rubber layer and a layer made of a mixture of fluororubber and fluororesin are formed on a metal substrate, the fluororesin layer, which is the release layer of the first surface layer, is 2.5 times thinner, and the surface layer and surface layer are Fluororubber with poor mold releasability is scattered in the vicinity, so a slight scratch on the surface layer will quickly reduce mold releasability.Therefore, the fixing performance is good due to the elasticity of the underlying rubber layer. , the durability is very poor,
Furthermore, when the operating temperature is raised to 200° C., the durability deteriorates even more, probably because the heat resistance of the surface fluororesin layer is poor.

The heating roller of this example, which has a rubber layer on the core metal, a fluororubber and fluororesin mixture on top of that, and a layer of base resin (PFA in this example) on top of that, has an operating temperature of 18
Shows excellent durability at both 0℃ and 200℃,
In addition, excellent fixing properties can be obtained due to the elasticity of the lower rubber layer.

In addition, under the operating temperature of 200℃, T1 of the metal substrate can be directly
Even though the amount of wear on the fluororesin layer is the same between the one with an FA layer and the one with a rubber layer, fluororubber, fluororesin mixture layer, and PFA layer sequentially, the difference in durability is the former PFA roller. As shown in Table 1, even when the PFA film thickness is 2.5 mm, PTFE is generally applied directly onto the metallic substrate (indicated as core metal in the table).

Fluororesin coated rollers such as PFA and FEP have inferior fixing properties compared to elastic rollers, but their durability (refers to the offset property in which the paper does not wrap around the heating roller when the paper is passed through) can be used at a working temperature of 120°C. PTFE at °C,
Both PFA and FEP have over 250,000 pieces.

Also, at the operating temperature of 200℃, PFA and FEP have a heat resistance of P
Since it is slightly weaker than TFE, the durability is lower at 200,000 sheets for PFA and 150,000 sheets for FEP.

This seems to be because, in reality, there are parts where the metal part protrudes close to the surface layer due to the unevenness of the core metal, and the mold releasability deteriorates in these parts. On the other hand, in the heating roller to which the present invention is applied, the unevenness of the metal substrate is absorbed by the rubber layer, and this is probably because the thickness of the outermost PFA layer is almost uniform.

Regarding specific numerical examples of the present invention, the thickness of the lower rubber layer is preferably 0.1 to 2iis + preferably 0.2 to 1.0 mm from the viewpoint of elasticity and thermal conductivity. In addition, the lower rubber layer is made of silicone rubber, fluororubber, and EPDM.
etc. are desirable from the viewpoint of heat resistance.Additionally, by mixing carbon black or a good heat conductor such as a gold-resistant compound such as nickel oxide, titanium oxide, or cobalt oxide inside the rubber, the thermal conductivity can be increased and the fluororesin of the upper layer can be mixed. , the adhesion with the fluororubber mixture also increases.

The mixture of fluororubber and fluororesin provided on the rubber layer 2b has a thickness of 5 to 100p, preferably 5 to 3
If it is between 0IL and 0IL, the fluororesin component floating on the surface layer will be uniform, and the surface will have less unevenness and the adhesiveness with the fluororesin on the outermost layer will be good.

The outermost layer of fluororesin is PTFE and PFA.

A resin with good mold releasability such as FEP is desirable, and a fixing roller with a thickness of 3 to 100%, preferably 5 to 30%, takes advantage of the elasticity of the lower rubber layer and has excellent long-term durability. can get.

In addition, the firing process is 320°C to 4°C when PFA resin is used.
A baking time of 15 minutes to 1 hour is desirable at a temperature of 00°C, more preferably a baking time of 240 to 280°C before the above baking process.
It is desirable to carry out the first firing at a temperature of 0.degree. C. to heat-treat the rubber layer 1 to prevent depolymerization.

Other examples of the present invention will be shown below.

1. In FIG. 1, the lower rubber layer 2b is coated with heat-resistant rubber such as silicone rubber, fluororubber, or EPDM,
Fluororubber is placed on top of this rubber layer.

The mixture 2a made of fluororesin was applied to a thickness of 10 μm using a spray gun or other coating means, dried at room temperature or heated by an infrared heater, etc.
Drying is carried out with hot air at a temperature of 0.degree. C., and then an emulsion of FEP resin is applied to a thickness of IO#L on this layer. 26 after this
Baking is performed at 0° C. for 30 minutes to form an FEP resin layer on the outermost layer. In this way, FEP resin melts at a relatively low temperature and has a low melt viscosity, so it flows easily during firing.
Therefore, when the fluororesin/fluororubber mixture layer 2a is fired, it easily follows the unevenness of the surface caused by the phenomenon in which the fluororesin floats to the surface layer side, and has excellent, extremely uniform adhesion. Furthermore, since it can be fired at a lower temperature, it has the advantage that the underlying rubber layer will not be deteriorated. Furthermore, in order to strengthen the adhesiveness, it is very effective to roughen the surface of the fluororubber or fluororesin layer after drying it with hot air.

2. Even if PTFE resin is used in place of the PFA resin used in the first embodiment of the present invention, the fixing roller can be manufactured under the same manufacturing conditions.

The effect at this time is almost the same as that of PFA resin, but it exhibits better heat resistance than PFA resin.

3. In FIG. 1, the lower rubber layer 2b is coated with a heat-resistant rubber such as silicone rubber, fluororubber, or EPDM,
Fluororubber is placed on top of this rubber layer.

The mixture 2a made of fluororesin was applied to a thickness of 10 IL using a coating means such as a spray gun, dried at room temperature or heated by an infrared heater, etc.
Perform hot air at 0°C. Further, on this layer, FEP resin in an emulsion state is applied to a thickness of 51L. 26 after this
Firing is performed at 0° C. for 15 minutes to form an FEP resin layer.

Furthermore, powdered PFA resin is applied to a thickness of 10 IL by electrostatic coating on the FEP resin layer, and baked at 300° C. for 30 minutes. In this way, a PFA4td fat layer with excellent heat resistance is formed on the outermost layer. This FEP resin layer, which has the characteristics of low melt viscosity and easy flow, is made of fluororubber.

By covering the fluororesin layer, it provides surface uniformity, and on top of that, PFA4N resin, which has excellent heat resistance and has a higher melting temperature than FEP resin, is formed on the surface layer to provide excellent bonding strength. can be obtained, and one surface layer of the fluororesin layer can be made sufficiently thick.

A similar effect can also be obtained by using PTFE resin as the outermost layer. In the case of PTFE resin in particular, it does not melt completely even at high temperatures and has many pinholes and severe unevenness, resulting in a large surface area and Since the FEP resin flows into the unevenness and exhibits excellent adhesive properties, a product with extremely high strength can be obtained.

As explained above, since the present invention has a mixed layer of fluororubber and fluororesin as the intermediate layer, the lower rubber layer and the upper resin layer are strongly bonded to each other, thereby increasing the surface resin thickness. We were able to provide an elastic roller with excellent durability and abrasion resistance. Therefore, it also has the advantage of good fixing properties and very excellent image quality.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a fixing roller according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a fixing device to which the roller of the present invention is applied. 2 is a resin layer, 2a is a mixed layer, 2b is an elastic layer, and 3 is a substrate. Applicant: Canon Co., Ltd. drawings n'r drawings (no changes to the internal nature) Figure 1 Figure 2 Procedures Amendment (voluntary) April 9, 1980 Commissioner of the Patent Office Kazuo Wakasugi Fixing roller and Relationship between the fixing device 3 having the same, the person making the correction + lr Patent applicant address 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (too
) Canon Co., Ltd. Representative Kaku nIE Department') 1ri 14, Agent ゛°°Pa residence 3-30-25 Shimomaruko, Ota-ku, Tokyo 148, Specification and drawings to be amended, Power of attorney 6, M1 main Contents: ・Engrave the Meiji NPS and drawings (no changes to the contents) and the power of attorney as attached.

Claims (4)

[Claims] (1) It has a roller base, a rubber layer provided on the roller base, a mixed layer including rubber and resin provided on the rubber layer, and a resin layer provided on the mixed layer. Fuser roller. (2) In a fixing device including a fixing roller for fixing an unfixed image to a recording material, the fixing roller has a roller base, a rubber layer provided on the roller base, and a rubber layer provided on the rubber layer. A mixed layer having rubber and resin. (j) a resin layer provided on the mixed layer; (3) r:1-ra base, a rubber layer provided on the roller base, a mixed layer having rubber and resin provided on the rubber layer, and a rubber layer provided on the mixed layer. A fixing roller comprising a resin layer having a relatively low melting temperature, and a resin layer provided on the resin layer and having a melting temperature higher than that of the resin layer. (4) In a fixing device including a fixing roller for fixing an unfixed image to a recording material. The fixing roller has a roller base, a rubber layer provided on the roller base, a mixed layer including rubber and resin provided on the rubber layer, and a relatively melting temperature layer provided on the mixed layer. A fixing device comprising: a resin layer having a low melting temperature; and a resin layer provided on the resin layer and having a melting temperature equal to or higher than that of the resin layer.