JPH0719101B2 - Method of manufacturing elastic rotating body for fixing and elastic rotating body for fixing - 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 its use is most suitable for office machines. Specifically, it is used for general paper conveying rollers, belts, particularly effective ones for heat fixing. Examples include rollers and belts.

(Prior Art) Conventionally, in the field of general transport, there are many conditions required for a rotating body, and elasticity for ensuring transportability, releasability for durability and dirt prevention, especially friction of the rotating body. This is an antistatic effect. However, the rotating body satisfying such a condition is complicated and expensive.

These conditions are particularly important for those used in image forming apparatuses. For example, a roller having a core metal coated with tetrafluoroethylene resin is used as the heating roller in contact with the toner image, and a roller coated with a rubber layer is used as the pressure roller in pressure contact with the heating roller to increase the heating / pressing time of the toner image. Is common.

Recently, attempts to combine the elasticity of rubber and the surface property of resin are found in JP-A-58-2864, JP-A-58-5770 and JP-A-58-27175. These suggestions are
The former discloses a roller whose surface is coated with a mixed paint of fluororubber and a fluororesin, and the latter discloses a roller whose surface is coated with a mixed paint of fluororubber and a fluororesin. .

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-shrinkable tube (FEP: fluorinated ethylene propylene) having a diameter larger than the diameter of the rubber roller in advance.
After shrinking by heating at 4 ° C, it was heated at 182.2 ° C 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 offset, and a roller utilizing 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 is a roller disclosed in JP-A-57-89785 and a roller disclosed in JP-A-59-74578. However, these rollers have a resin layer on the surface which is not sufficiently baked. Or, even if it receives this, the resin layer on the surface does not have heat resistance and abrasion resistance, so that the abrasion is severe and even a few thousand sheets cannot be passed, and it cannot be used as a fixing roller.

(Problems to be Solved) With respect to these conventional techniques, the applicant has developed a technique for heating and firing a novel resin in the presence of the lower elastic layer.
is suggesting.

In the process of rapidly cooling the elastic rotating body after performing this configuration, variations in wear resistance and adhesion strength of the elastic rotating body after manufacturing become large, and in extreme cases, durability may be reduced. It was

The present invention recognizes that it brings more stability to the content proposed by the applicant as a new technology.

(Object of the Invention) An object of the present invention is to provide a manufacturing method and a manufacturing method capable of further stabilizing the wear resistance and durability of an elastic rotating body having surface resin characteristics and having moderate elasticity as a whole. To provide an elastic rotating body.

(Summary of the Invention) The present invention achieves the above object, focusing on the relationship between the resin layer and the elastic body layer of the elastic rotating body, and at the time of manufacturing the elastic rotating body, the elastic body layer and the resin are formed by a cooling method after firing. It was clarified that it affects the adhesion and durability of the layer.

The present invention relates to a method for manufacturing a fixing elastic rotating body in which a resin layer is formed on an elastic layer by firing the resin layer on the elastic layer while maintaining the elastic layer at a temperature lower than that of the resin layer. When the resin layer is heated to a high temperature at which the resin material can be baked and the resin layer is baked on the elastic layer, and then rapidly cooled, the surface temperature of the resin layer is equal to or lower than the fixing temperature of the elastic layer. The temperature is higher than that of the elastic layer.

The present invention also provides a fixing elastic rotating body having a resin layer obtained by firing a resin material on an elastic layer, wherein the elastic layer is maintained at a temperature lower than that of the resin material during firing, and the resin layer is subjected to rapid cooling after firing. The elastic layer is maintained at a temperature higher than that of the elastic layer until the temperature of the elastic layer becomes equal to or lower than the fixing temperature.

Hereinafter, examples will be described based on the configurations of the respective inventions.

(Embodiment) FIG. 1 is an illustration of an embodiment of a fixing device having a fixing roller which is an elastic rotating member 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 silicone rubber (in this example, 0.3 mm to
(Predetermined thickness within 0.8 mm), the elastic layer 12 having a rebound resilience of 65% to 85%, and PFA resin (tetrafluoroethylene resin; perfluoroalkoxyethylene resin copolymer), P on the upper layer 13
Fluorine resin such as TFE (tetrafluoroethylene resin) is used for the elastic layer 12
A thinner resin layer (predetermined thickness in the range of 10 μm to 25 μm in this example) has a film strength of 50 kg / cm ² or more. Similarly, the pressure roller 2 is thicker than the thickness of the silicone rubber elastic layer 12 on the core metal 21 such as stainless steel or iron (in this example, a predetermined thickness within the range of 4 mm to 10 mm), and its impact resilience is Of 65% to 85% of elastic layer 22 and PFA, P on the upper layer
Fluorine resin such as TFE is thinner than the thickness of the thick elastic layer 22 (in this example, a predetermined thickness within the range of 5 μ to 35 μ) and the film strength is 50 kg.
23 with 23 / cm ² or more of resin layer.

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 15 × 10 ³ cal · cm / sec · cm ² · ° C.) 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 slicon rubber with less compression set, has excellent surface releasability and wear resistance, and is highly durable with sufficient elasticity. 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 fixing roller and the pressure roller are synergistic with each other. Due to the effect, the defects of each other are complemented and the advantages of each other are improved, and the obtained image quality and fixing property can be made excellent and the durability becomes excellent.

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 silicon layer. It has been found that the cooling method after firing the fluororesin is important for strengthening the adhesion between the fluororesin and the rubber layer.

That is, in this example, the fluororesin was applied onto the rubber layer, baked by the method as described above, and then rapidly cooled. The surface temperature of the fluororesin during the quenching was the temperature of the lower rubber layer when the rotor was used,
It has been found that in the case of fixing, it is necessary that the temperature is higher than the temperature of the lower rubber layer until the fixing temperature, that is, between 150 ° C and 230 ° C, or lower.

FIG. 4 is a diagram showing the relationship between the surface temperature of the fluororesin layer during cooling and the surface temperature of the rubber layer. The solid line shows the surface temperature of the fluororesin layer, and the broken line shows the temperature of the rubber layer. In this graph, the temperature of the fluorine resin layer and the temperature of the rubber layer indicated by the curves are
At the temperature of (170 ° C), the temperature of the fluorine resin layer was higher than the temperature of the rubber layer and passed the temperature To before that, and the relationship between the two was reversed.

By using the cooling method as described above, the film strength of the fluororesin is increased and the adhesion with the rubber layer is further strengthened. This is because when the fluorocarbon resin layer is rapidly cooled, the crystallinity of the fluorocarbon resin is lowered (90 to 95% or less) and the film becomes strong (according to the experiments of the present inventors, the quenching time is the surface temperature of the fixing roller). 45 seconds or less is recommended until the temperature reaches 200 ° C). In addition, the temperature drop curve of the fluororesin is higher than the temperature of the rubber layer up to the vicinity of the fixing temperature, and the temperature of the rubber layer remains below the fixing temperature until the fluororesin layer is melted by firing and sufficiently cooled to form a complete film. Therefore, the formed film follows the rubber layer at a temperature lower than the fixing temperature during use. Therefore, when used as a fixing roller, the rubber layer thermally expands at the fixing temperature during actual use, and is larger than the coefficient of thermal expansion of the fluororesin layer. Since the rubber layer follows the fixing temperature at the time of use, the rubber layer applies sufficient pressure to the fluororesin from the inside, apparently the fluororesin exerts a contracting force on the rubber layer. It becomes a workable form and the adhesion becomes very strong.

In this way, it is possible to form a fluorine resin film having sufficient strength and adhesiveness to the rubber layer.

Furthermore, the fluororesin film formed by such a cooling method has an advantage that the surface is smooth and a surface having a surface phase (Rz) of 3 μ or less can be formed, so that it is not necessary to finish polishing thereafter. .

According to the present invention, the above-described effects can be applied to the fixing roller as a fixing roller for 300,000 sheets or more while maintaining the excellent fixing effect and releasability.

Hereinafter, specific examples will be described together with comparative examples. As the above fixing roller: thickness of resin layer (PTFE) 10μ, thickness of elastic silicon rubber layer is 0.5mm, outer diameter is 40mm, inner diameter is 28mm
While maintaining the temperature of the rubber layer at a low temperature of 260 to 280 ° C or less as described above, the fluorine resin layer is baked at a high temperature of 340 to 380 ° C, which is a temperature at which it can be sufficiently baked, and then to 40 ° C. It was possible to observe the temperature drop curves of the fluorine resin layer and the rubber layer as shown in FIG. 4 by attaching the fixing roller to the maintained water tank. At this time, it is necessary to appropriately change the temperature of the water tank depending on the heat capacity of the fixing roller.

When the fixing process was carried out with the fixing roller thus manufactured, no abnormality was found in the fixing roller even after fixing 300,000 sheets, and the fixing effect was stable and satisfactory. In addition, this fixing roller exhibited physical properties sufficient to withstand further durability.

As a comparative example, the following fixing roller was manufactured and a similar experiment was conducted, and the result was as follows.

1) When the roller A was cast in a water tank at 15 ° C. and rapidly cooled by using the firing method of this example, temperature drop curves of the fluorine resin layer and the rubber layer as shown in FIG. 5 (a) were obtained.

In this fixing roller, the temperature drop of the fluorine resin layer was too early as compared with the temperature drop of the rubber layer, so the adhesive strength near the fixing temperature was weak, and the nail was lifted at the endurance of 220,000 sheets.

2) As the roller B, the firing method of this example was used to control the temperature in the constant temperature bath and gradually cool it to obtain temperature drop curves of the fluorine resin layer and the rubber layer as shown in FIG. 5 (b).

In this fixing roller, the surface property of the fluorocarbon resin was poor and the film strength was slightly weak, and the fluorocarbon resin film was cut off by the toner that had been offset to the thermistor section at 150,000 sheets.

3) Use a normal firing furnace as the roller C, and use a firing method in which high temperature is applied to not only the fluorine resin but also the rubber layer.
When it was air-cooled at room temperature, temperature drop curves of the fluorine resin layer and the rubber layer as shown in FIG. 5 (c) were obtained.

In this fixing roller, the rubber layer is completely deteriorated, the nail bites into the roller after 30,000 sheets, and the rubber layer is destroyed, and at the same time, the adhesion is weak. It has come off. Also, the cleaning web was often stained by the offset toner.

FIG. 3 shows a firing method for the elastic rotating body 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, and includes a magnetron 105, a waveguide 106 for transmitting a high frequency (950 MHz to 2450 MHz) generated from the magnetron 105, and a waveguide. An openable and closable resin container 102 having a metallic high-frequency reflector 103 connected to the pipe,
Infrared lamp 111 for infrared external heating, two each at the top and bottom
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 addition, since it has the releasability and elasticity of the fluororesin, it has transferability and cleanability (however, the cleaning roller performs cleaning in the order of surface energy, etc.). Therefore, uniform application of the release agent and uneven transfer are prevented, and the advantages of excellent abrasion resistance are exhibited 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.

The effect of using the elastic rotating body of the present invention as a fixing roller (including a belt-shaped roller) is that it is excellent in wear resistance and surface releasability, and that the surface characteristics of the resin layer and the elastic characteristics of rubber are sufficiently exhibited. In addition, it has an excellent effect of following the toner image and other rollers, and has a very long life.

Further, when the elastic rotating body of the present invention is applied to one roller (including a belt) that sandwiches the recording material of the fixing device, curling of the recording material is prevented, and the fixed image is clear and has good fixability. The effect can be maintained for a longer period of time than 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 invention's effect〕

According to the present invention, as described above, when the elastic layer is applied to the resin layer at the fixing temperature, tension is applied by thermal expansion so that the concavo-convex portions are brought into close contact with each other at the contacting portions thereof, and the contraction force of the resin layer is generated. By pressing the convex parts of the elastic layer with each other to improve the adhesiveness to each other, and by further cooling rapidly after firing, the smoothness of the surface of the elastic roller is enhanced, and it is easy to transfer 500,000 sheets in general transfer. Even if the rotating body for fixing is used, it is possible to perform fixing processing for 300,000 sheets or more while maintaining excellent fixing effect and releasability.

Further, according to the present invention, the same effect as described above can be maintained over a wide temperature range from the room temperature when the elastic roller is used, and an elastic rotating body adapted to various temperature ranges can be obtained under the same manufacturing conditions. it can.

Further, the elastic rotating body of the present invention has a considerably smooth surface, which can reduce the necessity of polishing.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a fixing roller (including a belt-shaped roller) which is an elastic rotating body and a fixing device having the fixing roller of the present invention, 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 present invention. FIG. 4, FIG. 5 (a), FIG. 5 (b), and FIG. 5 (c) are graphs showing the temperature decrease during cooling after firing. 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.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masaaki Sakurai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Michio Shigenobu 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 Inside S-T

Claims (2)

[Claims] 1. A method of manufacturing an elastic rotating body for fixing, comprising forming a resin layer on an elastic body layer by firing a resin material on the elastic body layer, wherein the elastic body layer is maintained at a temperature lower than that of the resin material. While heating the resin material on the elastic layer by heating it to a high temperature at which the resin material can be baked, and then rapidly cooling, the surface temperature of the resin layer is until the temperature of the elastic layer becomes equal to or lower than the fixing temperature. Is a temperature higher than that of the elastic layer. 2. An elastic rotating body for fixing having a resin layer obtained by firing a resin material on an elastic layer, wherein the elastic layer is maintained at a temperature lower than that of the resin material during firing, and the resin layer is rapidly cooled after firing. An elastic rotating body for fixing, characterized in that it is kept at a temperature higher than that of the elastic layer until the temperature of the elastic layer becomes equal to or lower than the fixing temperature.