JP4207202B2 - Fixing member, fixing device, fixing method, and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing member utilizing an electrostatic transfer process, and more particularly to a roller fixing member such as an electrostatic copying machine and an electrostatic copying printer, a fixing device using the same, a fixing method, and an image forming apparatus. is there.

Various fixing methods have been proposed and implemented as conventional fixing devices for image forming apparatuses such as general electrophotographic copying machines. Among them, a roller fixing type, in particular, a roller pair. A heating roller fixing device (heat roll fixing method) in which at least one is a heating roller heated by a heat source has become mainstream.
Here, of the pair of rollers, a roller in contact with the surface on the image bearing side of the recording material is referred to as a fixing roller or a heating roller, and the other roller is referred to as a pressure roller.

In the roller fixing type fixing device, since the fixing roller directly contacts the image bearing surface of the recording material, a part of the developer (hereinafter referred to as toner) constituting the image on the recording material is fixed. A so-called “offset phenomenon” is likely to occur that adheres to and adheres to the surface of the roller, and this adhered toner is transferred again onto the recording material as the roller rotates.
As a means for preventing this offset phenomenon, offset of a highly releasable material (non-adhesive material) such as fluororesin such as polytetrafluoroethylene resin (hereinafter referred to as PTFE) or silicon rubber has been conventionally applied to the outer peripheral surface of the fixing roller. A means for improving the releasability (non-adhesiveness) of the surface layer of the fixing roller by providing a prevention coating layer has been adopted.

However, the conventional offset preventing means has the following problems.
In the arrangement of the offset prevention layer, a roller provided with a coating layer of PTFE or other fluororesin exhibits excellent non-adhesiveness. May stick and contaminate the roller surface.

In recent years, there has been a strong demand for higher durability of various parts such as fixing rollers due to the trend toward lower costs, improved serviceability, and regulations on industrial waste. However, pure fluororesin is much stronger in terms of wear resistance. However, the fixing roller provided with a coating layer of a fluororesin such as PTFE has a drawback that the wear resistance is not sufficient and the life is short.
That is, the surface of the fixing roller is worn by being rubbed by a cleaning unit such as a blade, a release agent coating unit, a recording material separation claw, a temperature detection element, a pressure roller, or the like. Further, the recording material passing between the fixing roller and the pressure roller is also rubbed. When a large amount of paper (recording material) is passed, paper dust is generated from the paper and adheres to the fixing roller. This paper dust is removed by a cleaning blade or the like brought into contact with the fixing roller. However, the generation of paper dust is particularly remarkable at the edge portion of the paper, and the roller is formed by various inorganic fillers contained in the paper dust. The surface is worn.
The fixing roller tends to lose its original releasability due to loss of smoothness due to surface wear.

In addition, since the coating layer has high resistance, the surface thereof is greatly charged by frictional charging due to sliding contact with the recording material / pressure roller and other roller contact members, and the toner on the recording material is fixed by electrostatic action. A so-called electrostatic offset phenomenon is likely to occur due to being attracted to the roller surface layer.
The fluororesin is negatively charged by sliding with the recording material or the like. When the toner has a positive polarity, the toner is attracted to the electric field of the negatively charged fluororesin coating layer and easily adheres to the surface of the fixing roller due to an electrostatic offset phenomenon.

As a means for improving the wear resistance, the wear resistance of fluorine resin or the like generally has a relatively high hardness such as glass powder, silica, silicon carbide powder, diamond powder, corundum powder, metal powder such as nickel or iron. It can be improved by mixing an inorganic filler, but if the mixing amount is small, the effect of improving the wear resistance is not sufficient, and if the mixing amount is increased, the releasability becomes worse, and the fixing roller The surface property also deteriorates, and the offset prevention effect decreases.
In addition, these fillers have poor dispersibility in the fluororesin, and even if they can be dispersed, the adhesion between the filler and the fluororesin is poor, and part of the filler on the fixing roller coating layer is detached due to durability. Phenomenon occurred.
In the case of poor dispersion, a portion with less filler is first scraped into a streak shape or a mottled shape due to durability, and the toner is embedded in the shaved portion and the non-adhesiveness of the fixing roller is often lowered.
Further, when the filler is detached, the toner is buried in the detached portion, or the removed filler acts as an abrasive on the contrary to accelerate the wear.

Attempts were made to make the particle size of the filler finer, but the adhesion between the filler and the fluororesin was poor, and conversely the entire fluororesin layer was worn.
Further, when the release layer is in the state as described above, the fixing member becomes unusable any more, so it is necessary to replace it with a new fixing member, leading to waste of resources. The load on the environment will increase.

The following solutions have been proposed for these problems, but they have the following drawbacks and have not yet been completely solved.
As one method, it has also been proposed to form a film in which a resin having excellent durability and adhesion is mixed (see, for example, Patent Document 1).
However, the films formed by mixing these materials have the disadvantages that the surface structure is likely to be uneven depending on the manufacturing conditions, and that the life varies depending on the roller and is cheap.
Further, since the surface tension is not controlled, it is difficult to say that the releasability is sufficient. In particular, the release agent is not applied to the fixing member, which has become the mainstream in recent years, and only the release agent in the toner is used. In oilless fixing, which is a fixing method that performs this, there is a potential problem that offset is likely to occur.

In addition, there is a method that discloses a method in which the fluororesin layer is expected to float on the surface by heating (for example, see Patent Document 2).
However, since the layer is thin and the structure is not controlled so that the surface tension suitable for mold release can be maintained, if the surface is damaged in some way, a polyimide layer with poor release properties is exposed, This became the core of toner adhesion, which could lead to jams. In particular, this tendency was remarkable in oilless fixing which has become mainstream in recent years.

Furthermore, it has also been proposed to form a film mixed with a resin having excellent durability and adhesion (for example, see Patent Document 3).
However, since the surface tension is not controlled, it is difficult to say that the releasability is sufficient. In particular, oilless fixing (fixing method in which a release agent is not applied to the fixing member in advance and the release is performed only with the release agent in the toner) has a potential problem of causing an offset. It was.

In addition, there is also a disclosure that is expected to improve wear resistance while maintaining releasability by mixing fluororesin particles or once melted fluororesin particles in a binder resin (see, for example, Patent Document 4). .
This causes a problem that the components of the fluororesin particles are detached from the binder resin when subjected to strong rubbing or digging force by a separation claw for paper separation, and an offset is generated from the hole generated there. was there.

It has also been proposed to form a film in which a fluororesin is mixed with a resin having excellent durability and adhesion (see, for example, Patent Document 5).
However, in the case where a liquid is mixed with a resin having a large specific gravity, such as a fluororesin, depending on the adjustment conditions and manufacturing conditions of the liquid, the fluororesin of the release layer may be deposited due to sedimentation of the fluororesin during coating. There were drawbacks in that the ratio was easily uneven and the life was varied and cheaper by the roller.
In particular, oilless fixing (fixing method in which a release agent is not applied to the fixing member in advance and the release is performed only with the release agent in the toner) has a potential problem of causing an offset. It was.

JP-A-4-243287 JP 2000-298411 A JP 2001-312170 A JP 2001-331049 A Japanese Patent No. 3261166

  As described above, the above prior art has unevenness in the surface structure, insufficient releasability, scratches on the surface, surface tension is not controlled, and offset occurs from the fluororesin release holes. However, there is a problem that the life is fluctuated, and in particular, offset is likely to occur in oilless fixing.

  Therefore, the present invention has been made to solve the above-described problems. It improves wear resistance, uniforms heat conduction, prevents electrostatic offset and other offsets in general, and releases the release layer. It is an object of the present invention to provide a fixing member, a fixing device, a fixing method, and an image forming apparatus that can prevent image quality and improve image quality.

First aspect of the present invention, it possesses a releasing layer provided on the heat resistant substrate and the heat-resistant substrate surface, in a fixing member for fixing an image of toner including wax on a recording material, the release The mold layer is formed by a mixture of a fluororesin and a heat-resistant resin having a deflection temperature under load (ASTM D648, 1.82 MPa) larger than the temperature of the fixing member at the time of fixing, and the mixture aggregates the powder of the heat-resistant resin. A co-continuous structure formed by mixing the fluororesin powder in a state of being allowed to melt, melting both the resins, and then cooling.
Alternatively, the present invention provides a fixing member comprising a network structure formed by mixing mesh fibers made of the heat-resistant resin into the fluororesin powder and melting both the resins .
A second aspect of the present invention provides the fixing member according to the first aspect, wherein the heat resistant resin of the release layer contains a conductive filler.
According to a third aspect of the present invention, there is provided the fixing member according to the first or second aspect, wherein an adhesive layer is provided between the release layer containing the heat-resistant resin and the base layer.
The invention according to claim 4 is characterized in that a part of the heat-resistant resin connected has an adhesive force to the base of the release layer, and a part is bonded to the base. The fixing member according to any one of 3 is provided.
According to a fifth aspect of the present invention, there is provided the fixing member according to any one of the first to fourth aspects, wherein the release layer containing the heat resistant resin has an elastic layer between the base material and the release layer. .
A sixth aspect of the present invention provides the fixing member according to any one of the first to fifth aspects, wherein the heat-resistant resin is a resin that can be liquefied at room temperature before film formation.
According to a seventh aspect of the present invention, there is provided the fixing member according to any one of the first to sixth aspects, wherein a heat conductive filler is contained in the heat resistant resin of the release layer.
According to an eighth aspect of the present invention, there is provided a fixing member having a heat-resistant substrate and a release layer provided on the surface of the heat-resistant substrate, and fixing the wax-containing toner as an image on a recording material. The mold layer is formed by a mixture of a fluororesin and a heat-resistant resin having a deflection temperature under load (ASTM D648, 1.82 MPa) larger than the temperature of the fixing member at the time of fixing, and the mixture aggregates the powder of the heat-resistant resin. Mixed with the fluororesin powder in a state of being melted, and then melted both of the resins, and then cooled to form a co-continuous structure or a mesh-like fiber made of the heat-resistant resin. A fixing device using the fixing member according to any one of claims 1 to 7 provided with a network structure formed by mixing the two resins and melting both of the resins.
According to a ninth aspect of the present invention, there is provided a fixing method using the fixing device according to the eighth aspect, wherein a release agent is supplied to the surface of the release layer.
According to a tenth aspect of the present invention, there is provided the fixing device according to the eighth aspect, further comprising means for supplying a release agent to the surface of the release layer.
An eleventh aspect of the present invention provides a fixing method using the fixing device according to the eighth or tenth aspect, wherein the surface of the release layer is cleaned.
According to a twelfth aspect of the present invention, there is provided the fixing device according to the eighth or tenth aspect, further comprising means for cleaning the surface of the release layer.
According to a thirteenth aspect of the present invention, there is provided an image forming apparatus using the fixing device according to the eighth, tenth or twelfth aspect.

According to the first aspect, since the fixing member is not easily deformed even when pressed by a blade or the like, the pressing member does not bite, wear resistance is improved, and wear due to paper dust can be reduced. Furthermore, compared to the dispersion of normal particulate heat-resistant resin, the heat-resistant resin on the surface of the release layer is not easily detached even when subjected to the force of digging by the separation claw, etc. And wear is difficult to occur. Furthermore, the network structure is particularly advantageous because it is particularly difficult to remove the heat-resistant resin.
According to the second aspect of the present invention, electrostatic offset can be prevented and the release property can be maintained because no filler that affects the release property is added to the fluororesin.
According to the third aspect, the release layer can be prevented from being peeled off by the adhesive layer when it is rubbed with a blade or the like.
According to the fourth aspect, the adhesiveness between the heat-resistant substrate and the release layer can be improved without using an adhesive layer, and the number of steps can be reduced.
According to the fifth aspect, compared to the case where the release layer is formed of only the fluororesin, the heat-resistant resin is mixed, so that the toner can be uniformly heated, the nip width can be increased, and the paper can be passed. It is possible to improve the adhesion to an elastic layer advantageous for increasing the linear velocity.
According to the sixth aspect of the present invention, since the leveling after coating is performed compared with the coating with powder, the smoothness of the coating film is good, and even when the surface shape of the release layer is transferred to the image at the time of fixing, the image quality is improved. It is possible to suppress the deterioration of the substrate, and even if there are fine irregularities of the substrate, it can be sufficiently covered because it is liquid, and the contact area increases, so that the adhesion to the substrate can be improved. Become.
According to the seventh aspect, when the heat conductive filler is contained in the heat resistant resin, the heat conductivity can be improved. In this case, the fluororesin is added with a filler that affects the releasability. Therefore, the release property of the release layer can be maintained.
According to the eighth aspect, since the fixing member is not easily deformed even when pressed by a blade or the like, the pressing member does not bite, wear resistance is improved, and abrasion due to paper dust can be reduced. Since the plurality of regions are connected at least inside the release layer, even if the heat resistant resin on the surface of the release layer is subjected to the digging force by the separation claws or the like compared to the dispersion of the normal particulate heat resistant resin Since it is not easily detached, it is possible to obtain a fixing device in which holes are not easily opened, and thus image defects are not easily generated or worn.
According to the ninth aspect, the oil component is held in the heat-resistant resin portion, and the offset prevention coating layer can exhibit stable non-adhesiveness over a long period of time.
According to the tenth aspect, the oil component is held in the heat resistant resin portion, and the offset preventing coating layer can exhibit a stable non-adhesive property over a long period of time.
According to the eleventh aspect, since they are not easily deformed even when pressed by a cleaning means such as a blade, they are difficult to bite and wear, and the wear property due to rubbing on the surface of the release layer is also improved.
According to the twelfth aspect, even when pressed by a cleaning means such as a blade, they are not easily deformed so that they are difficult to bite, and therefore are not easily worn. Even if the surface of the release layer is rubbed by various inorganic fillers contained in the powder, the wear resistance is improved for the same reason.
According to the thirteenth aspect, since the period in which the fixing member can be used is greatly increased, which leads to resource saving, it is possible to reduce the load on the environment which has been regarded as a problem in recent years.

Hereinafter, embodiments of the present invention will be described in detail.
First, with reference to FIG. 1 to FIG. 9, examples and effects of the construction in which heat-resistant resins are connected to each other inside the roll release layer will be described by examples (claims 1, 2 and 3).
In the present invention, the release layer provided on the outermost surface of the fixing member is a mixture of a fluororesin and a heat resistant resin having a deflection temperature under load (ASTM D648, 1.82 MPa) higher than the temperature of the fixing member at the time of fixing. And the contact angle of the release layer with respect to water is adjusted to be 80 ° or more.

That is, in the present invention, since the release layer is formed on the surface of the fixing member with a mixture of fluororesin and heat-resistant resin, the release layer is excellent in heat resistance.
Further, since the deflection temperature under load of the heat-resistant resin is set higher than the temperature of the fixing member at the time of fixing, a cleaning means such as a blade, a release agent applying means, a recording material separating claw, a temperature detecting element, a pressure roller It is difficult to be deformed even when pressed by, for example, so that it is difficult to bite and wear.
Also, when a large amount of recording paper is passed, paper dust is generated from the paper and adheres to the fixing member, and even if the release layer surface is rubbed by various inorganic fillers contained in the paper powder, it is worn for the same reason. Hard to do.

  In contrast, the conventional dispersion of the particulate heat-resistant resin 102 as shown in FIGS. 1 and 2 is less susceptible to abrasion than the case of using only a fluororesin, but the particulate resin exposed on the surface of the release layer. However, there is another problem that, when receiving a digging force by a separation claw or the like, it is detached and a hole is formed, and an offset is generated therefrom.

  On the other hand, in the case of the structure of the present invention in which the plurality of regions made of the heat resistant resin 102 are connected at least inside the release layer as shown in FIGS. Compared to the dispersion, the heat-resistant resin 102 on the surface of the release layer is not easily detached even when subjected to the force of digging by a separation claw or the like, so that the hole is less likely to be opened, and hence image defects and wear are less likely to occur.

  Also, since the wax that comes out of the toner and adheres to the surface of the release layer is not repelled on the release layer, the resin of the toner directly touches the release layer, causing offset or hot melt adhesion. The recording material does not wrap around the fixing roller functioning like an agent.

When the contact angle with water is less than 80 °, the wettability increases, so the adhesive strength of the toner resin increases rapidly, exceeding the adhesion prevention effect of wax, and the entire toner adheres to the surface of the release layer and is fixed. Cause a defect.
In the present invention, the contact angle was measured by forming a flat test piece of the surface layer material of the heat fixing member and measuring it at room temperature using a CA-X type manufactured by Kyowa Interface Science Co., Ltd.

  The thickness of the release layer is preferably 5 to 100 μm, and more preferably 10 to 50 μm. If the thickness is less than 5 μm, the period until the offset occurs when paper is passed is shortened, and if it exceeds 100 μm, cracks tend to occur.

The fluororesin of the release layer is not particularly limited as long as it contains a fluorine atom in the molecule.
Specifically, polytetrafluoroethylene (PTFE) and its modified product, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-ethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene Copolymer (FEP), tetrafluoroethylene-vinylidene fluoride copolymer (TFE / VdF), tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer (EPA), polychlorotrifluoroethylene (PCTFE) , Chlorotrifluoroethylene-ethylene copolymer (ECTFE), chlorotrifluoroethylene-vinylidene fluoride copolymer (CTFE / VdF), polyvinylidene fluoride (PVdF), polyvinyl fluoride ( VF) and the like.

  As the heat-resistant resin, a resin having a deflection temperature under load (ASTM: D648, 1.82 MPa) higher than the temperature of the fixing member at the time of fixing may be used. For example, when the temperature of the fixing member is 150 ° C. Polyamideimide (PAI), polyethersulfone (PES), polyetherimide (PEI), polyetheretherketone (PEEK), polyetherketone (PEK), polyethernitrile (PEN), polyarylate (PAR) Resin such as liquid crystal polymer (LCP), polybenzimidazole (PBI), polyimide (PI), polyphenylene sulfide (PPS) can be used. These may be used in combination.

  In order to form the release layer of the present invention using the above-mentioned fluororesin and heat-resistant resin, the heat-resistant resin powder is mixed in advance with the fluororesin powder in an agglomerated state, and both are melted and then cooled. 4, FIG. 5, and FIG. 6 can be connected to each other, or a co-continuous structure as shown in FIG. 7 can be formed.

Further, when a mesh-like fiber made of a heat-resistant resin is mixed with a fluororesin powder and both are melted, a network structure of the heat-resistant resin 102 as shown in FIGS. 8 and 9 can be formed.
The co-continuous structure in FIG. 7 and the network structure in FIGS. 8 and 9 are particularly advantageous because the heat-resistant resin 102 is particularly difficult to desorb.

In addition, as a method for adjusting the contact angle of the release layer formed on the fixing member with respect to water within a range of 80 ° or more, the mixing ratio of the fluororesin and the heat-resistant resin as the release layer forming material There is a method of changing the contact angle to water.
In this case, any of the above-described structures can be obtained by a combination of the types of fluororesin and heat-resistant resin, mixing method, and heating temperature.
For example, when the fluororesin is PFA and the heat-resistant resin is PEEK, as a method of setting the contact angle to 80 ° or more, the release layer may be formed by mixing the PEEK ratio within a range of 50 wt% or less. In this case, the melting point of PFA is 310 ° C., the melting point of PEEK is 332 ° C., and the melting point of PEEK is high. Both are melted at 380 ° C. Can be formed.
In the present invention, the form of the fixing member can be applied to any form such as a fixing roller and a fixing belt.

Next, the effects and actions of making the interval between the fluororesins smaller than the toner particle diameter will be described with reference to examples.
When the release layer was formed by making the interval between the fluororesins smaller than the particle size of the toner 104, and the interval was made smaller than the toner particle size, a heat-resistant resin having inferior release properties than the fluororesin was exposed on the surface. However, since the area where the toner 104 is in direct contact is reduced as shown in FIG. 10, the effect of preventing the electrostatic offset of the fluororesin is advantageous.

Next, the release property of the surface of the release layer in the above configuration will be described.
In the above structure, depending on the ratio of the heat-resistant resin and the fluororesin, the contact angle of the release layer with respect to water may be smaller than 80 °. In that case, for example, the fluorine may be further formed on the release layer once formed. It is possible to increase the contact angle to 80 ° or more by laminating the layer 111 made only of resin, and prevent offset as shown in FIG. 11, FIG. 12, FIG. 13, FIG. 14, FIG. An advantageous structure can be formed.

Next, a structure, an effect | action, and an Example by containing a conductive filler in a heat resistant resin are demonstrated.
By containing a conductive filler having a resistance of 10 ¹⁰ Ω · cm or less in the heat resistant resin, electrostatic offset can be prevented.
In this case, since the filler that affects the releasability is not added to the fluororesin, the releasability of the release layer can be maintained.
Here, a plurality of regions of the heat-resistant resin are connected at least inside the release layer, and by having continuity, the electrical conductivity is higher than when the heat-resistant resin is dispersed in the form of particles. It is good.
The amount of the conductive filler is preferably 1 to 50 wt% with respect to the fluororesin, and is preferably 5 to 75 wt% in total with the heat-resistant resin in order to maintain releasability.

  As electrically conductive particles, conductive polymers such as polyacetylene, polypyrrole and polythiophene, carbon such as ketine black and acetylene black, metals such as graphite, silver, nickel and copper, alloys thereof, mica, carbon, glass, etc. Examples include composite metals, metal oxides such as tin oxide and indium oxide, anions, cations, nonions, and amphoteric surfactants.

The structure, operation, and embodiment of the release layer and the underlying layer will be described (claim 7).
By providing an adhesive layer between the mold release layer and its base, mold release when subjected to rubbing by a cleaning means such as a blade, a mold release agent coating means, a recording material separation claw, a temperature detection element, a pressure roller, etc. Layer peeling can be prevented.

  Here, as the adhesive layer, various commercially available heat-resistant primers that enhance the adhesion between the heat-resistant substrate and the release layer can be used. For example, for an aluminum roller, a polyimide-based primer, a polyamide-imide-based primer, A polyethersulfone-based primer and a mixed primer of these are preferably used. For example, for a heat-resistant endless belt layer made of polyimide resin, a polyimide-based primer, a fluorine-based primer, or a mixed primer is preferably used.

Configurations, functions, and examples in the case of using a heat-resistant resin having adhesiveness with the ground will be described (claim 8).
As the resin for the release layer, a resin having heat resistance and adhesion on a metal cylindrical cored bar is selected. Examples include polybenzimidazole (PBI), polyimide (PI), polyamideimide (PAI), polyethersulfone (PES), polyphenylene sulfide (PPS), and PEEK (polyetheretherketone). These heat resistant resins are used as powder, for example. These heat-resistant resin powders are mixed and dispersed in fluororesin powders, and are simply coated on a metal cylindrical cored bar by electrostatic coating or the like.

As the adhesive fluororesin, a resin having a good melt film forming property by firing and having a relatively low melting point, preferably 250 to 310 ° C. is selected.
Specific examples include powders of low molecular weight polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA). It is done. As the low molecular weight polytetrafluoroethylene (PTFE) powder, Lubron L-5, L-2 (Daikin Industries), MP1100, 1200, 1300, TLP-10F-1 (Mitsui DuPont Fluorochemical) are known. As the tetrafluoroethylene-hexafluoropropylene copolymer (FEP) powder, 532-8000 (DuPont) is known. As the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) powder, MP-10, MP102, (Mitsui DuPont Fluorochemical) are known.

  By using the above resin, adhesion between the heat-resistant substrate and the release layer can be improved without using an adhesive layer, cleaning means such as blades, release agent application means, recording material separation nails, temperature detection Even when rubbed with an element, a pressure roller or the like, peeling of the release layer can be prevented, and there is no need to apply and dry the adhesive layer, and the number of steps can be reduced.

A configuration, an operation, and an example in which the same resin is used for the release layer and the base material will be described (claim 9).
For example, by using polyimide resin or PEEK resin as the heat-resistant resin constituting the release layer on the heat-resistant endless belt layer of polyimide resin or PEEK resin, and directly forming the release layer on the heat-resistant endless belt layer Adhesion between the heat-resistant substrate and the release layer can be improved without using an adhesive layer, and cleaning means such as blades, release agent application means, recording material separation claws, temperature detection elements, pressure rollers It is possible to prevent the release layer from being peeled off when subjected to rubbing or the like, and there is no need to apply and dry the adhesive layer, and the number of steps can be reduced.
In this case, the adhesiveness can be further improved as compared with the case where the release layer is formed on the metal cylindrical cored bar.

A configuration, operation, and examples in which an elastic layer is provided between the release layer and the substrate will be described (claim 10).
In order to heat the toner uniformly or to increase the nip width and increase the linear velocity of the paper, an elastic layer is provided, and the release layer formed on it can fix the uneven shape on the surface of the recording material Although the member is advantageous, it is possible to improve the adhesion to the elastic layer by mixing the heat-resistant resin as compared with the case where the release layer is formed of only the fluororesin, and the blade It is possible to prevent the release layer from being peeled off from the elastic layer when it is rubbed by a cleaning means such as a release agent application means, a recording material separation claw, a temperature detection element, a pressure roller, or the like.

A configuration, operation, and examples using a resin that can be made into a solution at room temperature as the heat-resistant resin will be described.
By using a resin that can be solutionized at room temperature as a heat-resistant resin, leveling after coating is performed compared to coating with powder, so that the smoothness of the coating film is improved, and the surface shape of the release layer during fixing is Even if it is transferred to an image, deterioration of image quality can be suppressed. Moreover, even if there are fine irregularities on the substrate, it can be sufficiently coated if it is liquid, and the adhesion area is increased, so that the adhesion to the substrate is improved.
Examples of the heat resistant resin used as the heat resistant resin coating layer include polybenzimidazole (PBI), polyimide (PI), polyamideimide (PAI), polyethersulfone (PES), and polyphenylene sulfide (PPS). These heat resistant resins are preferably used as a precursor solution or dissolved in a solvent. It is easy to mix and disperse the fluororesin powder in these solutions, and it is possible to easily coat the metal cylindrical core bar with good surface smoothness by dipping or coating. If the resin is thermoplastic, just evaporate the solvent, or if the resin is thermosetting, heat evaporate after evaporating the solvent to form a heat-resistant resin layer on the metal cylindrical cored bar Can do. Precursor solutions of polyimide (PI) and polyamideimide (PAI) are known, and polybenzimidazole (PBI) is dissolved in dimethylacetamide (DMA), and polyethersulfone (PES) is dimethylformamide, methylene chloride. , N-methyl-2-pyrrolidone is known to be soluble and these solutions can be used.

Configurations, functions, and examples in the case where a heat conductive filler is contained in the heat resistant resin will be described (claim 12).
In the present invention, when the heat resistant resin has a plurality of regions connected to each other and has continuity, the heat conductive filler can be contained in the heat resistant resin to improve the heat conductivity.
In this case, since the filler that affects the releasability is not added to the fluororesin, the releasability of the release layer can be maintained.
Specifically, as the thermally conductive particles, diamond, silver, copper, aluminum, marble, glass, boron nitride, alumina, silicon carbide, potassium titanate, aluminum nitride, boron nitride, mica, silica, titanium oxide, Examples thereof include magnesium oxide, beryllium oxide, talc, calcium carbonate, and a mixture of two or more of these. These addition amounts are preferably in the range of 10 to 50 wt% with respect to the heat resistant resin in order to maintain the releasability.

The structure, operation, and embodiment of the fixing device using the fixing member of the present invention will be described (claim 13).
FIG. 18 is a schematic configuration diagram of a fixing device using the fixing roller of the present invention. The fixing roller 1 and the pressure roller 2 are in pressure contact with each other with a predetermined pressing force in parallel up and down. A heat source 3 such as a halogen heater is in contact with the fixing roller 1, and a temperature detection element 4 such as a thermistor is in contact with the surface of the fixing roller 1, and the surface temperature of the fixing roller 1 is detected by this element 4, and the detection information thereof. Accordingly, the energization of the heat source 3 is controlled by a control circuit (not shown), and the surface temperature of the fixing roller 1 is managed at a predetermined temperature.
The fixing roller 1 has a recording material separating claw 6 that is urged and brought into contact with the spring 7, and the recording material wound around the surface of the fixing roller 1 is separated from the fixing roller 1.
In the pressure roller 2, the surface of the metal core 2b is covered with a silicon rubber layer 2a.
The roller pair is rotationally driven at a predetermined speed by a driving means (not shown). A recording material P on which an unfixed toner image T is formed and supported by an image forming unit (not shown) is introduced into a nipping pressure portion (fixing nip portion, nip width 5 to 6 mm) N of the roller pair, nipped and conveyed, and heat Fix the toner image with pressure.
On the surface of the fixing member, a release layer of a mixture of a fluororesin and a heat resistant resin is formed, and the heat resistance is excellent.
Further, since the deflection temperature under load (ASTM D648, 1.82 MPa) of the heat-resistant resin is set to be higher than the temperature of the fixing member at the time of fixing, even if it is pressed by a separation claw, a temperature detecting element, a pressure roller, or the like. There is no deformation and bite, so it is hard to wear.
Further, paper dust is generated through a large amount of paper (recording material), and even if the release layer surface is rubbed by various inorganic fillers contained in the paper dust, it is difficult to be worn.
In addition, since the wax that comes out of the toner and adheres to the release layer side is not repelled on the release layer, the toner resin or the like directly touches the release layer to cause offset or hot melt adhesion. The recording material does not wind around the fixing roller functioning like an agent.

The configuration, operation, and examples of the fixing method, the fixing device, its peripheral devices, and the image forming apparatus using the fixing member of the present invention will be described (claims 14, 15, 16, 17, and 18).
FIG. 19 is a schematic configuration diagram of the fixing device of this embodiment. The component parts common to those in FIG. 18 are given the same reference numerals and the description thereof will be omitted.
There is a roller body 5 as an oil supply member / cleaning member for the fixing roller 1. The roller body 5 is composed of a metal core 5a and an oil-impregnated heat-resistant felt 5b, and is controlled to contact and separate from the fixing roller 1 by an eccentric cam (not shown).
In the present invention, since the deflection temperature under load of the heat-resistant resin (ASTM D648, 1.82 MPa) is set larger than the temperature of the fixing member at the time of fixing, even when pressed by the cleaning means and the release agent applying means. They are difficult to deform, they are difficult to bite in, and are therefore difficult to wear.
In addition, since the contact angle is controlled so that the release agent applied to the release layer is not repelled, the toner resin or the like directly touches the release layer to be offset, or a hot melt adhesive is used. The recording material does not wind around the fixing roller.
Furthermore, when a release agent is applied to the release layer of the fixing roller 1 in this embodiment, the oil component is held in the heat-resistant resin portion, and the offset prevention coating layer can exhibit stable non-adhesiveness over a long period of time.

Table 1 shows the experimental results of an actual machine equipped with the fixing device according to the present invention.
Table 1 shows a comparison result between the present invention and the conventional filler.
The actual machine was evaluated for charging potential, offset property, and durability life.
Model used: Spirio 3550 (Ricoh Co., Ltd.)
Charging potential: A surface potential meter Trek Model 347 is used to measure the surface of the fixing roller while the paper is passing, and the time average is calculated.
Offset property: 100 consecutive ruled line charts are copied and evaluated in 4 levels (good → ◎ → ○ → △ → × → bad)
Abrasion resistance: Four-step evaluation based on the amount of surface scraping after continuous paper passing (good → ◎ → ○ → △ → × → bad)
Desorption of heat-resistant resin: Four-step evaluation based on the amount of holes due to continuous paper passage and desorption (good → ◎ → ○ → △ → × → bad)
Temperature distribution: A thermistor is attached to the center and both ends of the fixing roller in the axial direction, and the temperature difference is measured and evaluated in four stages (temperature difference small → ◎ → ○ → △ → × → large)

  In Table 1, the temperature of the fixing member at the time of fixing is 150 ° C., and the deflection temperature under load of the heat-resistant resin of Example 1 (ASTM D648, 1.82 MPa) is 203 ° C. and the load of the heat-resistant resin of Example 2 The deflection temperature is 152 ° C., the deflection temperature under load of the heat resistant resin of Example 3 is 203 ° C., the deflection temperature under load of the heat resistant resin of Example 4 is 152 ° C., and the contact angle of the release layer with respect to water is as in Example 1. 105 °, Example 2 107 °, Example 3 104 °, Example 4 106 °, Comparative Example 1 108 °, Comparative Example 2 109 °, Comparative Example 3 105 °, and Comparative Example 4 107 °, Comparative Example 5 is 104 °, and Comparative Example 6 is 106 °. The release layer is formed as a heat-resistant substrate on the top of an aluminum cylindrical cored bar with a thickness of 30 μm.

It is explanatory drawing of the release layer in which the conventional heat resistant resin particle was disperse | distributed individually in the fluororesin. It is explanatory drawing of the mold release layer which the conventional fluororesin particle | grains each disperse | distributed in heat resistant resin. It is a top view and sectional drawing in case the heat-resistant resin particle of the mold release layer of this invention is a connection structure. It is the top view and sectional drawing in case the heat-resistant resin particle of the mold release layer of this invention is another connection structure. It is sectional drawing in case the heat resistant resin particle of the mold release layer of this invention is a connection structure. It is sectional drawing in case the heat resistant resin particle of the mold release layer of this invention is another connection structure. It is sectional drawing in case the heat resistant resin particle of the release layer of this invention is a co-continuous structure. It is sectional drawing in case the heat resistant resin of the mold release layer of this invention is a network structure. It is a schematic cross section of the network structure of the structure where the heat resistant resin of the release layer of the present invention is difficult to be detached. FIG. 4 is an explanatory cross-sectional view of the relationship between the length of a fluororesin and the toner diameter between heat resistant resins of the present invention. It is sectional drawing of the example at the time of coat | covering the surface of the mold release layer of this invention with a fluororesin. It is sectional drawing of the other example at the time of coat | covering the surface of the mold release layer of this invention with a fluororesin. It is sectional drawing of the other example at the time of coat | covering the surface of the mold release layer of this invention with a fluororesin. It is sectional drawing of the other example at the time of coat | covering the surface of the mold release layer of this invention with a fluororesin. It is sectional drawing of the other example at the time of coat | covering the surface of the mold release layer of this invention with a fluororesin. It is sectional drawing of the other example at the time of coat | covering the surface of the mold release layer of this invention with a fluororesin. It is sectional drawing of the other example at the time of coat | covering the surface of the mold release layer of this invention with a fluororesin. FIG. 3 is a configuration diagram of a fixing device in which the fixing roller of the present invention is equipped with a cleaning device. FIG. 2 is a schematic configuration diagram of a fixing device in which a fixing agent application device is provided on the fixing roller of the present invention.

Explanation of symbols

1 Fixing roller 1a
DESCRIPTION OF SYMBOLS 1b Metal core 2 Pressure roller 2a Silicon rubber layer 2b Metal core 3 Heat source 4 Temperature detection element 5 Cleaning roller 5a Metal core 5b Oil impregnation heat resistant felt 6 Separation claw 7 Spring 101 Fluoro resin 102 Heat resistant resin 103 Mold release agent 104 Toner 111 Fluorine resin layer

Claims (13)

Possess a releasing layer provided on the heat resistant substrate and the heat-resistant substrate surface, in a fixing member for fixing an image of toner including wax on a recording material,
The release layer is formed of a mixture of a fluororesin and a heat-resistant resin having a deflection temperature under load (ASTM D648, 1.82 MPa) larger than the temperature of the fixing member at the time of fixing,
The mixture is a co-continuous structure formed by mixing the fluororesin powder in a state where the heat-resistant resin powder is agglomerated, and melting both the resins and then cooling.
Alternatively , a fixing member comprising a network structure formed by mixing mesh-like fibers made of the heat-resistant resin into the fluororesin powder and melting both the resins . The fixing member according to claim 1, wherein a conductive filler is contained in the heat-resistant resin of the release layer. The fixing member according to claim 1, further comprising an adhesive layer between the release layer containing the heat-resistant resin and the base layer. The part of the connected heat-resistant resin has an adhesive force with respect to the base of the release layer, and part of the heat-resistant resin is bonded to the base. Fixing member. The fixing member according to claim 1, wherein the release layer containing the heat-resistant resin includes an elastic layer between the base material and the release layer. The fixing member according to claim 1, wherein the heat-resistant resin is a resin that can be liquefied at room temperature before film formation. The fixing member according to claim 1, wherein a heat conductive filler is contained in the heat resistant resin of the release layer. In a fixing member having a heat-resistant substrate and a release layer provided on the surface of the heat-resistant substrate, and fixing a wax-containing toner as an image on a recording material, the release layer includes a fluororesin, A deflection temperature under load (ASTM D648, 1.82 MPa) is formed by a mixture with a heat-resistant resin larger than the temperature of the fixing member at the time of fixing, and the mixture is formed by agglomerating the powder of the heat-resistant resin. Mixed into the body, melted both of the resins and then cooled, mixed with a co-continuous structure, or mixed with fibers of the heat-resistant resin, and mixed with the fluororesin powder. A fixing device using the fixing member according to claim 1, comprising a network structure formed by melting the toner. 9. A fixing method using the fixing device according to claim 8, wherein a release agent is supplied to the surface of the release layer. 9. The fixing device according to claim 8, further comprising means for supplying a release agent to the surface of the release layer. 11. A fixing method using the fixing device according to claim 8, wherein the surface of the release layer is cleaned. 11. The fixing device according to claim 8, further comprising means for cleaning the surface of the release layer. An image forming apparatus using the fixing device according to claim 8, 10 or 12.

Images