JPH0695261B2 - Elastic rotating body for fixing and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a general elastic rotating body, and more particularly to an elastic rotating body having a surface resin layer.

The present invention relates to a manufacturing method and an elastic rotating body obtained by the method, and the use thereof is most suitable for office machines. Specifically, it is used for heating and fixing general paper conveying rollers, belts, particularly effective ones. Examples include rollers and belts.

(Prior Art) Conventionally, in this field, a roller having a core metal coated with tetrafluoroethylene resin as a heating roller in contact with a toner image is used as a pressure roller in pressure contact with the heating roller in order to increase the heating and pressing time of the toner image. A roller coated with a rubber layer is generally used.

However, since the surface of the heating roller provided on the toner image side is close to a rigid body, the heat transfer speed at the time of pressing the toner image to transfer heat is slow, and it is also familiar with unevenness of the toner image. Few. Therefore, compared with the case where the obtained image-forming and fixing rubber roller is used on the toner image side, the amount of curl generated on the sheet on which the toner image is fixed is large. On the other hand, when a rubber roller is used as the toner roller, offset is increased due to poor releasability, and wear resistance is low, and wear is caused by the contact member (separation claw, sensor, etc.) and partial fixing failure and partial The target offset also increases.

Thus, both the rubber roller and the resin roller have advantages and disadvantages, and an elastic roller having these advantages has been desired.

In response to this, the roller proposed is Tokuseki Sho 58-2864.
JP-A-58-5770 and JP-A-58-27175.
In these proposals, the former is a roller coated with a mixed coating of fluororubber and a fluororesin on the surface of a metal roller, and the latter is a roller coated with a mixed coating of fluororubber and a fluororesin on the surface of a rubber roller, Each is disclosed.

However, these documents disclose that the above-mentioned mixed paint disclosed in Japanese Patent Laid-Open No. 57-135871 is applied to a desired roller. Therefore, it is impossible to obtain a fixing roller suitable for actual fixing and use conditions. . Specifically, when a roller was produced based on the above technical disclosure, a large amount of resin component could not be obtained on the surface of the mixed layer, and the limit was about 2 μ at most. Further, since the surface of the resin layer of this roller has not been sufficiently baked, it is worn so much that it cannot pass several thousand sheets. Only a very thin layer can be formed on the fixing roller itself, and in order to obtain the desired elasticity, a new rubber layer is formed below the mixed layer as disclosed in JP-A-58-5770. It is already known that it is necessary.

However, if a rubber layer is provided on the base of the roller and the above-mentioned mixed layer is formed on it and directly baked at a high temperature of 400 ° C. for 30 minutes at high temperature, the amount of fluororesin on the surface of the mixed layer is slightly increased (about 3 μm). ), The rubber layer thereunder depolymerizes and loses elasticity.

Therefore, obtaining the characteristics as a roller is contrary to increasing the resin component on the surface of the mixed layer, and it has been difficult to obtain an elastic roller satisfying both characteristics so as to withstand long-term use. .

In particular, as an elastic roller for fixing, pressurizing, or heating used in a fixing device, the elasticity of the rubber layer and the increase of the resin component on the surface of the mixed layer are sufficient for satisfying various purposes such as fixability, heating, and pressing. It is extremely important to obtain a roller having releasability and elasticity that can withstand long-term practical use, but it has been beyond the wish.

On the other hand, Japanese Patent Publication No. SHO 47-47 has been put into practical use in which a rubber roller is simply formed and a resin layer is formed on the surface thereof.
There is a roller disclosed in Japanese Patent No. 20747. This roller is made by polishing the surface of a silicone rubber roller, applying an adhesive, and covering it with a heat-shrinking tube (FEP: fluorinated ethylene propylene) having a diameter larger than the diameter of the rubber roller in advance.
After shrinking by heating at ℃, it was heated at 182.2 ℃ for 1 hour. However, in this method, it is difficult to obtain a roller having a predetermined shape because the amount of heat shrinkage is not uniform, and the inner surface must be cleaned extremely well after the resin tube is formed in advance. Further, with the present technology, the thickness of the heat shrinkable tube can be formed only to 50 μm or more, so that the elasticity of the lower rubber layer is canceled out, and a roller making use of the elasticity cannot be obtained by this method. That is, the roller according to this publication is inferior in accuracy and is expensive due to the large number of manufacturing steps, and it is not possible to obtain an appropriate fixing effect.

Further, there are rollers disclosed in JP-A-57-89785 and JP-A-59-74578, but none of them shows the structure of the manufactured roller, and the former and the latter are fired. Considering that the temperature is 300 ° C and the former is that the fluorine resin material is tetrafluoroethylene-6 fluoropyropyrene copolymer, this roller has a surface resin layer that has not been sufficiently baked. It is so worn that even thousands of sheets cannot be passed, making it unusable as a fixing roller.

This is because these are obtained by coating the surface of the silicone rubber roller with a fluororesin solution, but when the fluororesin solution is a tetrafluoroethylene resin, crystallization of the fluororesin is at a high temperature of 327 ° C. (crystal melting point) or higher (preferably Is 340 ℃ -360 ℃)
When the fluororesin solution is a tetrafluoroethylene-perfluorovinyl ether copolymer, it is obtained after being heated to a high temperature (preferably 320 ° C. to 340 ° C.) of 306 ° C. (crystal melting point) or higher. Fluorine resin does not melt at low temperature of ℃,
This is because the resin characteristics cannot be obtained because the powder remains in a dried powder state and is not formed into a film. Moreover, in these publications, the desired value was 0.1 μm for fluorine resin in the former.
~ 50μ, in the latter it is said that the resin pressure of 0.1mm or less is good, there is no basis for feasibility. Thus, not only the resin characteristics cannot be obtained by low-temperature firing below the crystal melting point such as 300 ° C., but also the adhesiveness between the rubber layer and the resin surface is poor and the resin strength is weak, so that they easily peel off.

If the adhesion between the rubber layer and the resin surface layer is poor, slippage occurs easily between these layers due to local stress generated when the fixing roller nips and conveys the sheet, causing image distortion and fixing failure. Not only that, but offset occurs and the resin layer is torn by the separating claw. In particular, since there is no abrasion resistance as a resin when baked at a low temperature of 300 ° C.
As shown in No. 8, even if there is no paper jam, etc.
It is capable of transporting 30,000 sheets and is difficult to put into practical use.

[Object of the Invention]

An object of the present invention is to provide a method for producing an elastic rotating body which has surface resin characteristics and has moderate elasticity as a whole, and which is superior in fixing property, abrasion resistance and releasability to a conventional one, and a method for obtaining the same. To provide an elastic rotating body.

(Summary of the Invention) The present invention focuses on the relationship between a resin layer and a rubber layer of an elastic rotating body, and when manufacturing the elastic rotating body, a rubber layer and a resin are applied by a method of applying an unbaked resin material on the rubber layer. It was clarified that it has a great influence on the adhesion and durability of the layer.
That is, the present invention, in a manufacturing method for manufacturing a fixing elastic rotating body having a resin layer on an elastic body, a resin dispersion prepared by mixing an unsintered resin material on the elastic body is applied at a temperature of 15 ° C or lower. Then, while the resin dispersion is heated to a high temperature at which the resin material is fired, the elastic body is maintained at a temperature lower than this resin dispersion to form a resin layer on the elastic body. is there.

Further, the fixing elastic rotating body of the present invention, an elastic body, a resin dispersion obtained by mixing an unbaked resin material on the elastic body is applied while being held at 15 ° C. or lower, and then the resin dispersion is And a resin layer formed on the elastic body while maintaining the elastic body at a temperature lower than the resin dispersion while being heated to a high temperature for firing.

(Embodiment) FIG. 1 is an illustration of an embodiment of a fixing device of the present invention having a fixing roller of the present invention.

In FIG. 1, reference numeral 1 is a fixing roller on the side in contact with an unfixed toner image, and 2 is a pressure roller that rotates in pressure contact with the fixing roller 1.
Both are examples of the fixing roller of the present invention. The specific configuration is as follows.

The fixing roller 1 has a relatively thin silicon rubber (in this example, 0.3 mm to 0.8 mm) on a cored bar 11 having good heat conduction such as aluminum.
(a predetermined thickness within a range of mm) and an elastic layer 12 having a repulsion elastic modulus of 65% to 85%, and a PFA resin (tetrafluoroethylene resin;
Perfluoroalkoxy ethylene resin copolymer), PTFE
A fluorine resin such as (tetrafluoroethylene resin) is thinner than the elastic layer 12 (in this example, a predetermined thickness within the range of 10 μm to 25 μm) and has a resin strength of 50 kg / cm ² or more. Similarly, the pressure roller 2 is relatively thicker than the thickness of the silicon rubber elastic layer 12 on the cored bar 21 made of stainless steel, iron or the like (in this example,
Thickness of 4mm to 10mm), its impact resilience is 65%
Approximately 85% of the elastic layer 22 and a fluorine resin such as PFA or PTFE on the elastic layer 22 are thinner than the thick elastic layer 22 (5 μm in this example).
To a predetermined thickness within the range of 35 μm), and a resin layer 23 having a film strength of 50 kg / cm ² or more.

These rollers 1 and 2 are formed by the manufacturing method shown in FIG. 3 or a method conforming to the purpose thereof.
Briefly, it includes the following steps.

A silicone rubber layer vulcanized and molded on the core metal (heat conductivity 1.
4 × 10 ^{−4 to} 1.5 × 10 ⁻³ ) to form a silicone rubber roller having a desired shape. A preferred shape is an inverted crown type in which the central portion has a slightly smaller diameter than both ends. On this rubber roller surface, unfired fluororesin such as dispersion (a fluororesin powder dispersed in water with a surfactant), enamel or powdered fluororesin is sprayed or electrostatically coated over the entire length of the rubber roller. Apply it to a uniform thickness by a method such as powder coating. The display screen is heated to a glass transition point of 327 ° C. or higher of the crystalline melting point of the fluororesin to form a film-shaped resin film. Therefore, the silicon rubber roller coated with the unsintered fluorine resin needs to be heated to the crystal melting point or higher (PTFE 327 ° C or higher, PFA 306 ° C or higher).

However, although silicon rubber itself has excellent rubber properties such as impact resilience and compression set, it is more than 300 ° C, much less 3
When heated above 06 ℃ or 327 ℃, smoke or depolymerization occurs. These not only hinder the formation of a good quality fluororesin layer, but also impair the rubber properties of the silicone rubber itself. Therefore, the overheating of the rubber layer loses the function of the rubber layer and the characteristics of the resin layer, and the condition suitable for fixing is lost.

For these reasons, in the examples of the present invention, the silicon rubber roller itself is kept under heating at a low temperature (up to 300 ° C. or less) so as not to cause smoking or depolymerization, and the crystal is formed in the coating layer of the fluororesin. A firing method that gives a high temperature state above the melting point was adopted.

Specifically, a method of rapidly heating the unsintered fluororesin on the surface while rapidly cooling the rubber layer from the inside of the core bar, or the dielectric loss tangent of the liquid fluororesin (dispersion, enamel) itself is the dielectric of the rubber layer. In addition to the dielectric heating method (see FIG. 3) utilizing the fact that it is greater than the tangent, any method that is suitable for this purpose is suitable for the present invention.

By this method, a thermal gradient is formed substantially in the thickness direction of the silicon rubber, but the temperature of about 260 ° C to 280 ° C is higher than the crystal melting point of the unbaked fluororesin (specifically, The firing temperature of 340 ℃ to 380 ℃ above 327 ℃ in PTFE is 5
It is given for about 10 minutes. After performing this firing, the roller is quenched. By this quenching, the crystallinity on the silicon rubber roller is 95% or less and the tensile strength is 50 kg / cm ² or more,
A baked fluororesin surface layer showing a resin characteristic of a contact angle with water of 100 degrees or more is formed in a strongly adhered state to a rubber roller and is sufficiently thick.

Accordingly, in the fixing roller 1 and the heating roller 2, the lower silicon rubber itself exhibits desired rubber characteristics almost the same as before the resin layer is formed, and the surface fluororesin layer exhibits completely baked resin characteristics. The adhesion of these layers is strong.

Now, referring back to FIG. 1, another configuration of the fixing device will be described.

Reference numeral 3 denotes a heater such as a halogen lamp for heating the fixing roller from the inside, and the surface temperature of the fixing roller is the optimum temperature (at which the toner can be always melted by the heater 3, the temperature detecting element 4 and the control means 31). Specifically, 160 ° C to 200
℃) is maintained.

Reference numeral 5 denotes an offset prevention liquid application means that also serves as a cleaning means for applying an offset prevention liquid such as silicon oil to the surface of the fixing roller. The coating means 5 may be felt-like, but a web is used in this example. The web 51 containing the offset prevention liquid is brought into contact with the fixing roller 1 by the elastic pressing roller 52 such as silicon sponge, and a small amount of the offset prevention liquid is applied to the surface of the fixing roller 1. The web 51 is a take-up roller.
By 53, the web is gradually taken up from the supply roller 54, and the contact surface of the web with respect to the fixing roller 1 is sequentially known by the control means (not shown).

The recording paper P carrying the unfixed toner image T is fed to the entrance guide 6
The toner image T is permanently fixed to the recording paper P by passing between the roller pair 1 and 2 while being guided by the sheet.
The separation claw 41 that contacts the surface of the roller 1 is provided to separate the recording material from the surface 1 of the roller.

The fixing rollers 1 and 2 formed in this way have sufficient impact resilience because they are completely non-existent in the past, that is, the characteristics of the silicon rubber are not thermally deteriorated and the fluororesin is completely baked. It enables the use of silicone rubber with less compression set, has excellent surface releasability and wear resistance, and has sufficient elasticity and high durability. Moreover, even if the stress generated when the toner image is fixed on the recording paper is concentrated between the silicone rubber layer and the fluororesin layer, the strength of the fluororesin layer is high,
The adhesion between them is also good.

As shown in FIG. 2, another characteristic configuration of the above configuration is that the elastic layer 12 of the fixing roller has a thickness t ₁ , the resin layer 13 of the fixing roller has a thickness t ₂ , the elastic layer 22 of the pressure roller has a thickness t _3. , And the thickness t ₄ of the resin layer 23 of the pressure roller are as follows.

That is, the roller 1 has t ₁ > t _{2 the} roller 2 has t ₃ > t ₄ , and preferably t ₄ <t ₂ <t ₁ <t _{3 With} this configuration, basically, the mutual phase of the fixing roller and the pressure roller is The surplus effect complements each other's defects and improves each other's advantages, resulting in excellent image quality and fixability, and excellent durability.

The durability of the fixing roller having the above-mentioned characteristics is most affected by the film strength of the fluororesin layer and the adhesion between the fluororesin and the silirone rubber layer. It was discovered that the method of applying an unsintered resin material onto the rubber layer is important in order to strengthen the adhesion between the fluororesin and the rubber layer.

That is, as described in the specification of Daikin's tetrafluoroethylene resin display purgeon D-1, it is generally about 17 ° C.
A temperature between two first-order transition points of about 26 ° C. is used, but when the present inventor applies a coater roll as a rubber layer while keeping the temperature of the discharge below 15 ° C. or less, preferably 13 ° C. or less. We have found that the best conditions are obtained.

This is probably due to the following effects. In other words: 1. At low temperature, secondary particles and tertiary particles, which are aggregated of initial particles, are less likely to occur, so finer irregularities on the rubber surface are more likely to enter small particles, resulting in a mechanically strong adhesion. Is obtained.

2. Furthermore, when considering the charging of the discharge purgeon, it is normally charged, but at low temperature it is more strongly charged, so it is thought that a larger Coulomb force acts between the rubber layer and the adhesion improves. .

At this time, the temperature of the base rubber layer is preferably slightly lower than the temperature of the applied fluororesin dispersion.
This is to avoid the risk of destabilizing the temperature distribution of the display sponge itself and consequently achieve good coating. Specifically, when the temperature of the dispersion is 13 ° C, the temperature of the rubber layer surface is preferably about 10-12 ° C.

Here, the method of applying the fluororesin dispersion paron 52 to the elastic rotating body 1 will be described with reference to FIG.

The fluororesin dispersion 52 is stored in the vessel 53 and is constantly stirred by the stirring rod 51. Further, the temperature of the lower layer portion and the temperature of the upper layer portion are detected by the temperature sensors 56 and 57, and when there is a temperature difference, the controller 58 enhances the stirring.

Further, pipes 54 through which cooling water passes and pipes 55 having a built-in heater are alternately provided on the outside of the melter 53 to keep the liquid temperature constant.

The lower layer of the coater roller 50 is set in this liquid so that the elastic rotator 1 is pressed onto the coater roller at a total pressure of about 3 kg to coat the elastic rotator 5 to 5 times.
Rotate and apply so that 7 layers are provided.

FIG. 3 shows a firing method of the fixing roller of the present invention. The device shown in the figure is a specific example of a heating system that uses both an induction heating device and infrared external heating. The magnetron 105 and the high frequency (950MHz to 2450MHz) generated by the magnetron 105 are used.
A resin container 102 that can be opened and closed, and has a waveguide 106 for transmitting a wave and a metallic high-frequency reflection plate 103 on the inner surface connected to the waveguide.
And two infrared lamps for upper and lower infrared heating
1 and has a reflective shade.

In the resin container 102, a fan 100 for generating an air flow in the hollow of the fixing roller 1 as a fixing roller and a fan 101 for generating an air flow in the container 102 are respectively provided from driving means outside the container. It is rotatably provided by driving. This container can be opened and closed around the fulcrum 108 and has a handle at the top.
Numeral 09 is fixed to the arm 107 for positioning the flange 1A of the roller 1 at the bottom.

110 is a control means of the device, which is a drive means 104 and a magnetron 10
5 and the operation of the infrared lamp 111 are performed by a variable timer (not shown) for a predetermined time depending on the closed state of the container and the input of a predetermined start signal.

Since the fixing roller 1 has a silicon rubber layer as a lower layer and a fluororesin dispersion on the surface, a large amount of high frequency is absorbed in the dispersion having a relative dielectric constant larger than that of the silicone rubber layer. Therefore, the fluororesin dispersion is rapidly heated to a high temperature of 340 ° C to 350 ° C by heating with a high frequency wave, an infrared ray and a constant temperature bath. At this time, since the silicone rubber layer has a low high frequency absorption rate, it is heated to a temperature of about 280 ° C. or lower rather than being heated to a temperature higher than that of the discharge purgeon. As a result, the roller characteristics described above can be obtained.

In the above examples, the fluororesin dispersion is, for example, tetrafluoroethylene resin dispersion D-1 manufactured by Daikin.
Is.

When the thickness of the resin layer in the present invention is 10 μ or more, the durability is 25
It can be improved to more than 10,000 sheets, and if it is 15μ or more, durability of 300,000 sheets or more can be obtained, and the fixing effect is reduced by the impact resilience of the rubber layer to compensate for the drawback that it decreases with the increase of its thickness. A high degree of fixability can be maintained. The present invention is particularly effective when a fluororesin is provided on the silicone rubber layer.

In the present invention, in addition to the above-described embodiment, as the fixing roller, a roller-shaped other belt-shaped roller (for example, an intermediate belt for simultaneous transfer and fixing), a cleaning roller, and a release agent supply roller are included. In particular, since it has the releasability and elasticity of the fluororesin, it has the transferability and the cleaning property (however, the cleaning roller performs cleaning according to the order of surface energy, etc.). It evenly coats the release agent and prevents transfer unevenness, and exerts the advantages of excellent abrasion resistance in each application.

Further, FIG. 1 shows an example of a heat fixing device, which is preferable as an embodiment of the present invention. A pressure fixing device for pressure fixing a toner image with a light pressure, a pressure for simultaneous transfer fixing, etc. The present invention can be applied to a fixing device or a heat fixing device.

Further, the above-mentioned example has a two-roller structure, but includes a heating roller, a pressure roller, a release agent supply roller of a fixing device having three or more rollers, or a cleaning roller and other belt-shaped rollers. The device is also included in the present invention.

[Advantages of the Invention] According to the present invention, as described above, the elastic layer applies tension to the resin layer by thermal expansion at the fixing temperature to create an engagement close contact state of the concave and convex portions at the mutual contact portions. The contraction force of the resin layer presses the convex parts of the elastic layer to improve the adhesion to each other, and the temperature of the resin layer applied on the rubber layer is kept low to smooth the surface of the elastic roller. In general transport, it is possible to easily transport 500,000 sheets, and as a fixing rotator, it is possible to perform fixing processing for 300,000 sheets or more while maintaining excellent fixing effect and releasability.

The effects common to the fixing roller (including a belt-shaped roller) of the present invention are excellent in abrasion resistance and surface releasability, and the surface characteristics of the resin layer and the elastic characteristics of rubber are sufficiently exerted to obtain toner images and other It also has an excellent effect of following the roller, and has a very long life.

In the fixing device of the present invention, when the fixing roller is applied to one roller (including a belt) that presses the recording material, curling of the recording material is prevented, and a fixed image is clear and has good fixability. The effect can be maintained for a longer period than ever before. Moreover, since the heat efficiency of fixing is good and the temperature required for fixing can be reduced (for example, about 20 ° C.), power consumption is reduced, and high-speed fixing recording can be achieved even with an apparatus having a small power distribution.

The elastic rotating body of the present invention has a considerably smooth surface and can reduce the need for polishing.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of a fixing roller (including a belt-shaped roller) corresponding to the elastic rotating body of the present invention and a fixing device having the fixing roller, and FIG. 2 is a partially enlarged explanatory view of the fixing roller. FIG. 3 is an explanatory view of an embodiment of the manufacturing method of the fixing roller, and FIG.
The figure is an illustration of an embodiment of the manufacturing method of the present invention. 1 is a fixing roller, 2 is a pressure roller, 12 and 22 are silicone rubber elastic layers, and 13 and 23 are fluororesin layers.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaaki Sakurai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Masahiro Goto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Inichiro Yamamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Isamu Sakane 5-13-13 Ichiriyama, Otsu City, Shiga Prefecture En Tay

Claims (2)

[Claims] 1. A manufacturing method for manufacturing a fixing elastic rotating body having a resin layer on an elastic body, wherein a resin dispersion prepared by mixing an unsintered resin material is applied to the elastic body while keeping the temperature below 15 ° C. , And thereafter, the resin dispersion is heated to a high temperature at which the resin material is baked, and the elastic body is maintained at a temperature lower than the resin dispersion to form a resin layer on the elastic body. Method of manufacturing rotating body. 2. An elastic body and a resin dispersion prepared by mixing an unsintered resin material on the elastic body while maintaining the temperature below 15 ° C. and then applying the resin dispersion to a high temperature at which the resin material is baked. An elastic rotating body for fixing, comprising: a resin layer formed on the elastic body while maintaining the elastic body at a temperature lower than the resin dispersion while being heated.