JP6992674B2 - A method for manufacturing a coating liquid for forming a surface layer and a method for manufacturing an electrophotographic member. - Google Patents

Description

The present invention relates to a method for producing a coating liquid for forming a surface layer constituting an electrophotographic member, for example, a fixing member, and a method for producing an electrophotographic member. More specifically, the present invention has a perfluoropolyether compound and a hydroxy group on the surface. The present invention relates to a method for producing a surface layer forming coating liquid which is a surface layer forming coating liquid using a dispersion liquid containing a filler and having excellent dispersion stability, and a method for manufacturing an electrophotographic member using the same.

Conventionally, an electrostatic latent image formed on a photoconductor drum is developed with toner to form a toner image, the formed toner image is transferred to a recording paper, and the transferred toner image is heated and fixed. An electrophotographic image forming apparatus for forming an image on a recording paper is known.

In the electrophotographic members constituting such an electrophotographic image forming apparatus, many members are required to have releasability on the surface, for example, a photoconductor and toner transfer which are required to have toner transferability and cleanability. Examples thereof include an intermediate transfer body which is required to have properties, a fixing member which is required to have separability of a medium to which molten toner is attached, and among them, since the molten toner has adhesiveness, the fixing member is imparted with releasability. The demand is remarkable.

In the fixing device, the heated fixing member and the media to which the toner has been transferred are pressure-bonded, and the toner is fixed on the media by the heating and pressurizing treatment. The media needs to be separated.

In order to ensure the separability between the fixing member and the media, a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) is currently widely used as the surface layer of the fixing member, and in addition, a separating claw or a medium is used. Separability is improved by adding auxiliary means such as suction of the media and air blowing to the leading end of the media.

However, the fixing methods currently applied include further speeding up of printing in the future, no auxiliary means for energy saving and cost reduction, and expansion of media types such as thin paper that is difficult to separate. It is still insufficient for the request of. In addition, in order to reduce the downtime of the machine that directly leads to customer loss, it is required to make the member permanent, and in view of this situation, the fixing member for improving the separability between the fixing member and the media. Attempts are being made to improve the surface layer.

For example, in Patent Document 1, a fluoropolymer membrane such as PFA is treated with a strong alkali and then reacted with a silane coupling agent having a perfluoropolyether chain, so that the fixation is superior to that of an untreated fluoropolymer membrane. A liquid-repellent film having time separability and a method for producing the same are disclosed. However, according to the gas cluster ion beam (GCIB), in the production method disclosed in Patent Document 1, the water-repellent film formed can introduce a perfluoropolyether structure only into an extremely shallow surface portion. It is clear from the description that the strong alkali-treated part is exposed by etching, and it is difficult to make it permanent.

Further, Patent Document 2 has a specific perfluoroalkyl structure in a fixing member including a substrate, a functional layer arranged on the substrate, and an outer layer arranged on the functional layer. A fixing member capable of oilless fixing is disclosed by using a film obtained by cross-linking a polymer with a siloxane-containing cross-linking agent as a surface layer. In Patent Document 2, it is stated that a conductive filler or a non-conductive filler may be present, but the structure is different from that of the alkoxysilane-containing perfluoropolyether, and there is no description or suggestion regarding the dispersibility of the filler. Not done.

Further, Patent Document 3 discloses a fixing member for electrophotographic having a surface layer made of a heat-resistant elastomer in which an inorganic filler treated with a silane coupling agent containing a perfluoroalkyl group is dispersed. No description or suggestion has been made regarding dispersion stability in systems using fluoropolyethers and fillers.

As described above, a method of simply reducing the surface energy and achieving high releasability by forming a fluoropolymer film such as a polymer having a perfluoroalkyl structure as the surface layer of the fixing member has been widely studied. Since this fluoropolymer contains abundant fluorine atoms, it has excellent properties in terms of releasability, but it has many problems, and methods other than fluoropolymers are being searched for. ..

For example, as a method of realizing high releasability other than imparting releasability by simply reducing the surface energy using a fluoropolymer film, a filler such as a surface is added to a perfluoropolyether monomer containing abundant fluorine atoms. It has been studied to improve the releasability by reducing the contact area by adding a filler having a hydroxy group to the fluoropolymer and dispersing it to form a concavo-convex structure on the surface of the surface layer. However, in the combination of a perfluoropolyether monomer rich in fluorine atoms and a filler having a hydroxy group on the surface, the surface energy differs greatly between the two, so that when preparing a dispersion liquid for forming a surface layer, etc., Dispersibility and dispersion stability were extremely difficult.

Japanese Unexamined Patent Publication No. 2018-022056 Japanese Unexamined Patent Publication No. 2013-218324 Japanese Unexamined Patent Publication No. 10-10896

The present invention has been made in view of the above problems, and the problem to be solved thereof is a coating liquid for forming a surface layer of an electrophotographic member which is excellent in dispersion stability and releasability and can obtain a high-quality electrophotographic image. It is to provide the manufacturing method of the above and the manufacturing method of the electrophotographic member using it.

As a result of diligent studies in view of the above problems, the present invention obtains an alkoxy by forming a sufficient silanol structure at least in the preparation of a coating liquid for forming a surface layer used for forming an electrophotographic member composed of a base material and a surface layer. Even in the dispersion liquid of the combination of alkoxysilane and the filler, the surface energy differs greatly due to the interaction (for example, hydrogen bond or covalent bond) that occurs between the silanol structure of the silane and the hydroxy group of the filler. It has been found that a coating liquid for forming a surface layer having an excellent pot life can be obtained without causing aggregation or gelation, and the present invention has been made.

That is, the above-mentioned problem of the present invention is solved by the following means.

1. 1. A method for producing a coating liquid for forming a surface layer of an electrophotographic member consisting of at least a base material and a surface layer.
At least, step 1 of preparing a dispersion liquid A containing a perfluoropolyether compound having an alkoxysilane at the molecular terminal and water, and
Step 2 of adding a filler having a hydroxy group on the surface to the dispersion liquid A to prepare a mixed liquid, and
It also has a step 3 of dispersing the dispersion liquid A and the mixed liquid containing the filler to prepare the dispersion liquid B, and
A method for producing a coating liquid for forming a surface layer, which comprises providing a time interval for stirring the dispersion liquid A in an open state between the start time of the step 1 and the start time of the step 2.

2. 2. The method for producing a coating liquid for forming a surface layer according to item 1, wherein the electrophotographic member is a fixing member.

3. 3. The method for producing a coating liquid for forming a surface layer according to item 1 or 2, wherein the time interval between the step 1 and the step 2 is 1 hour or more.

4. The method for producing a coating liquid for forming a surface layer according to any one of items 1 to 3, wherein the filler having a hydroxy group on the surface is hydrophilic metal oxide fine particles.

5. A method for manufacturing an electrophotographic member consisting of at least a base material and a surface layer.
At least, step 1 of preparing a dispersion liquid A containing a perfluoropolyether compound having an alkoxysilane at the molecular terminal and water, and
Step 2 of adding a filler having a hydroxy group on the surface to the dispersion liquid A to prepare a mixed liquid, and
Step 3 to prepare the dispersion liquid B by dispersing the mixture liquid containing the dispersion liquid A and the filler.
It has a step 4 of applying and curing the coating liquid for forming a surface layer containing the dispersion liquid B on the base material to form a surface layer, and also
A method for manufacturing an electrophotographic member, which comprises providing a time interval for stirring the dispersion liquid A in an open state between the start time of the step 1 and the start time of the step 2.

According to the present invention, a method for producing a coating liquid for forming a surface layer of an electrophotographic member, which is excellent in dispersion stability and releasability and can obtain a high-quality electrophotographic image, and a method for producing an electrophotographic member using the same. Can be provided.

The technical features of the surface layer forming coating liquid and the electrophotographic member having the configuration specified in the present invention and the mechanism for expressing the effects are presumed as follows.

As described above, as a method for improving the releasability of the surface layer constituting the fixing member, low surface energy can be mentioned, but the current generally applied tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer weight can be mentioned. There was a limit to achieving the desired releasability by coalescence (PFA) alone.

As a countermeasure, in addition to the method of achieving high releasability by achieving low surface energy with simple PFA alone, a filler is further applied to the perfluoropolyether monomer containing a large amount of fluorine atoms in the molecular structure. Is added and dispersed to prepare a dispersion liquid, and the dispersion liquid is applied and cured on a substrate to form a surface layer having an uneven structure, thereby reducing the surface energy of the surface layer and reducing the contact area. High releasability can be achieved.

At this time, in the process of preparing the dispersion liquid, in the first step, when preparing the dispersion liquid containing the perfluoropolyether compound having an alkoxysilane at the molecular terminal and water, the preparation is carried out over a predetermined time. , Promotes silanolization of alkoxysilanes, and promotes silanolization by easily removing alcohol generated by hydrolysis of the alkoxysilane structure from the system by being able to prepare in an open container that is not closed as a preparation environment. Can be made to.

Then, by forming a sufficient silanol structure, the surface energy of the alkoxysilane varies greatly depending on the interaction (for example, hydrogen bond or covalent bond) that occurs between the silanol structure of the alkoxysilane and the hydroxy group of the filler. It is considered that a coating liquid for forming a surface layer having an excellent pot life can be obtained even in a dispersion liquid in combination with a filler without prolonging the aggregation and gelation of particles.

A process flow chart showing an example of a method for producing a coating liquid for forming a surface layer of the present invention. Schematic diagram showing an example of the structure of the fixing member having a surface layer according to the present invention. Schematic diagram showing an example of the overall configuration of an image forming apparatus applicable to the present invention.

The method for producing a coating liquid for forming a surface layer of the present invention is a method for producing a coating liquid for forming a surface layer of an electrophotographic member composed of at least a base material and a surface layer, and is at least a perfluoropolyether having an alkoxysilane at the molecular end. Step 1 for preparing a dispersion A containing a compound and water, step 2 for preparing a mixed solution by adding a filler having a hydroxy group on the surface to the dispersion A, and the dispersion A and the filler. The dispersion liquid A is prepared by dispersing the mixed liquid containing the above step 3 to prepare the dispersion liquid B, and the dispersion liquid A is stirred in an open state between the start time of the step 1 and the start time of the step 2. It is characterized in that a time interval is provided. This feature is a technical feature common to the inventions according to the following embodiments.

As an embodiment of the present invention, it is preferable that the electrophotographic member is a fixing member from the viewpoint of further exhibiting the effect intended by the present invention, because more excellent releasability can be exhibited. ..

Further, setting the time interval between the step 1 and the step 2 to 1 hour or more sufficiently promotes silanolization of the perfluoropolyether compound having an alkoxysilane at the molecular terminal in the step 1. It is preferable in that excellent dispersion stability can be realized.

Further, it is preferable that the filler having a hydroxy group on the surface is hydrophilic metal oxide fine particles in that a surface layer having better releasability can be formed.

Further, the method for producing an electrophotographic member of the present invention is a method for producing an electrophotographic member consisting of at least a base material and a surface layer, and at least a perfluoropolyether compound having an alkoxysilane at the molecular end and water are used. Step 1 to prepare the dispersion liquid A to be contained, step 2 to prepare a mixed liquid by adding a filler having a hydroxy group on the surface to the dispersion liquid A, and a mixed liquid containing the dispersion liquid A and the filler. The step 3 for preparing the dispersion liquid B by dispersing the dispersion liquid B, and the step 4 for applying and curing the surface layer forming coating liquid containing the dispersion liquid B on the base material to form the surface layer, and said It is characterized in that a time interval for stirring the dispersion liquid A in an open state is provided between the start time of the step 1 and the start time of the step 2.

Hereinafter, the components of the coating liquid for forming the surface layer and the member for electrophotographic of the present invention, and the embodiment for carrying out the present invention will be described in detail with reference to the drawings. In addition, in this application, "-" indicating a numerical range is used in the sense that the numerical values described before and after the numerical range are included as the lower limit value and the upper limit value. In the description of each figure, the numbers in parentheses at the end of the components represent the symbols in each figure.

<< Manufacturing method of coating liquid for surface layer formation and members for electrophotographic materials >>
Using the surface layer forming coating liquid of the present invention used for producing an electrophotographic member composed of at least a base material and a surface layer as a manufacturing method, a surface layer forming coating liquid is prepared through the following steps, and the surface layer forming coating liquid is used. A surface layer is formed on the base material using the material to produce an electrophotographic member, more specifically, a fixing member.

The specific manufacturing flow will be described with reference to the figures.

FIG. 1 is a process flow chart showing an example of a method for manufacturing a coating liquid for forming a surface layer and a member for electrophotographic of the present invention.

As shown in FIG. 1, the coating liquid for forming the surface layer of the present invention is used.
1A) Step 1: At least, a step of preparing a dispersion liquid A containing a perfluoropolyether compound having an alkoxysilane at the molecular terminal and water in a non-sealed state using an open preparation kettle.

1B) Step 2: A step of adding a filler having a hydroxy group on the surface to the dispersion liquid A prepared in step 1 to prepare a mixed liquid. In the present invention, the stirring time T of the dispersion liquid A is between the start of the step 1 of preparing the dispersion liquid A and the start of the step 2 of mixing the dispersion liquid A and the filler to prepare the mixed liquid. It is characterized by providing.

1C) Step 3: A step of preparing a dispersion B by dispersing a mixture containing the dispersion A and the filler using a desired disperser.

Manufactured via.

In addition, in the manufacturing method of electrophotographic members,
2A) Prepare an endless base material.

2B) An elastic layer is formed on the endless base material to prepare a laminated body.

1D) Step 4: The surface layer forming coating liquid containing the dispersion liquid B is applied and cured on the laminate in which the elastic layer is formed on the endless base material belt prepared in 2B) to form the surface layer. To manufacture electrophotographic members.

The surface layer can be formed by a known liquid coating method such as spray coating, spiral coating using a nozzle or a slit, dipping coating, or roll coater coating.

1E) The fixing member on which the surface layer is formed is heat-treated at a predetermined temperature and then heat-dried.

1F) Finally, the fixing member is subjected to humidity control treatment in a constant temperature and humidity environment.

One of the features of the method for producing a coating liquid for forming a surface layer of the present invention is that in step 1, a dispersion liquid A containing a perfluoropolyether compound having an alkoxysilane at the molecular terminal and water is carried out in an open kettle. .. This is to hydrolyze the alkoxysilane at the end of the molecule with water to form a silanol structure, and by removing the alcohol generated by this hydrolysis to the outside of the system, it is possible to promote silanolization of alkoxysilane, which is an equilibrium reaction. Can be done. Therefore, by carrying out the above reaction system in an open system environment, it is possible to facilitate the removal of the produced alcohol.

The open pot may have a structure without a lid, but from the viewpoint of preventing the entry of suspended matter from the outside, a breathable material such as a mesh cloth or a non-woven fabric made of long fibers may be used. May be covered with. Further, if necessary, a method may be used in which the gas containing alcohol stored in the space inside the kettle is forcibly discharged and ventilated to the outside.

Another feature of the method for producing a coating liquid for forming a surface layer of the present invention is the start of step 1 for preparing the dispersion liquid A and the step 2 for preparing the mixed liquid by mixing the dispersion liquid A and the filler. It is characterized in that a stirring time T for stirring the dispersion liquid A is provided as a time interval until the start time of the above. The stirring time T is preferably 25 ° C. for 1 hour or longer, and more preferably 25 ° C. for 10 hours or longer.

Further, it is possible to shorten the stirring time T between the start of the step 1 and the start of the step 2 by increasing the amount of the catalyst or heating, but heat generation or gel due to the runaway reaction is possible. There is a risk of (insoluble matter due to polymerization reaction).

The upper limit of the stirring time T of the dispersion liquid A is not particularly limited, but is preferably several days or less, for example, 200 hours or less at 25 ° C. in consideration of excessive progress of hydrolysis and formation of a gelled product. .. In addition, it is possible to avoid gel formation for a long time by reducing the amount of water or storing at a low temperature, but there is only a demerit of increasing the production cost.

Further, in step 2 of the method for producing a coating liquid for forming a surface layer of the present invention, the alkoxysilane produced in step 1 is hydrolyzed by mixing the perfluoropolyether compound and the filler to form a silanol structure and the filler. The interaction (hydrogen bond or covalent bond) that occurs with the hydroxy group of the material can improve the dispersion stability of the dispersion, and the perfluoropolyether compound and filler rich in fluorine atoms make it possible to improve the dispersion stability. It is possible to form a surface layer having an excellent uneven structure in which foreign matter and agglomerates are not generated, it is possible to realize low surface energy and a reduction in contact area, and it is possible to obtain a fixing member having excellent mold releasability.

The electrophotographic member (fixing member) produced by the above method is applied to a fixing device in an electrophotographic image forming apparatus. The image forming apparatus having the fixing member is a fixing device for fixing an unfixed toner image on a recording medium to the recording medium by heating and pressurizing using the fixing member, except that the fixing member is provided. It can be configured in the same manner as a known image forming apparatus having. In the image forming apparatus, the fixing member is subjected to a fixing step in a known electrophotographic image forming method.

As described above, the form of the fixing member may be a fixing sleeve or an endless fixing belt, but from the viewpoint of easily increasing the paper ejection angle at the time of fixing, which is advantageous for the above-mentioned separability. , It is preferably in the shape of an endless belt.

[Manufacturing method of electrophotographic members]
Examples of the electrophotographic member manufactured by using the coating liquid for forming the surface layer according to the present invention include members that require a high degree of releasability, but among them, it is extremely applicable to the fixing member. It is valid.

Hereinafter, the fixing member, which is a typical electrophotographic member, will be described.

[Fixing member]
The electrophotographic member according to the present invention has at least a base material and a surface layer, and more preferably, it is a fixing member having a structure in which a base material, an elastic layer, and a surface layer are laminated in this order.

In the present invention, the fixing member has a base material, an elastic layer, and a surface layer, except that the fixing member has a surface layer formed by using the surface layer forming coating liquid prepared by the method for producing a surface layer forming coating liquid of the present invention. Can be configured in the same manner as known fixing members arranged so as to overlap in this order.

The fixing member may be a fixing sleeve formed by supporting the above three layers on the outer peripheral surface of a metal cylinder, or may be an endless fixing belt having the above three layers.

The configuration of the fixing belt, which is an example of the fixing member, is shown in FIG.

FIG. 2 is a schematic view showing an example of the configuration of a fixing member (fixing belt) having a surface layer according to the present invention. FIG. 2A is a schematic view showing an example of the configuration of an endless belt-shaped fixing belt (1) having a surface layer according to the present invention, and FIG. 2B is shown in FIG. 2A. It is a schematic cross-sectional view which expanded the area A described in the fixing belt (1).

As shown in FIG. 2B, the fixing belt (1) is an endless belt in which a base material (2), an elastic layer (3), and a surface layer (4) are laminated in this order.

The details of each component of the fixing member will be described below (I: base material).
The base material (2) constituting the fixing member is made of, for example, a heat-resistant resin (heat-resistant resin). The term "heat resistance" as used in the present invention means that in electrophotographic image formation, the toner image is deformed at a temperature when the fixing member is used for fixing the toner image to a recording medium, for example, in a temperature range of 150 to 220 ° C. It means that the desired physical properties are expressed sufficiently stably without any problem.

The heat-resistant resin is appropriately selected from resins that do not substantially modify or deform at the above-mentioned operating temperature of the fixing member, and may be used alone or in combination of two or more.

Examples of the heat-resistant resin applicable to the present invention include polyphenylene sulfide, polyarylate, polysulfone, polyethersulfone, polyetherimide, polyimide, polyamideimide, and polyetheretherketone. Among them, polyimide is preferable from the viewpoint of heat resistance.

Polyimide can be obtained, for example, by heating the precursor polyamic acid at 200 ° C. or higher, or by advancing the dehydration and cyclization (imidization) reaction by using a catalyst. The polyamic acid may be produced by dissolving a tetracarboxylic dianhydride and a diamine compound in a solvent and performing a polycondensation reaction by mixing and heating, or a commercially available product may be used. Examples of the diamine compound and the tetracarboxylic dianhydride include the compounds described in paragraphs (0123) to (0130) of JP2013-25120A.

The heat-resistant resin is a main material constituting the base material of the fixing member according to the present invention, and the content thereof may be a sufficient amount for forming the base material. The content of the heat-resistant resin in the base material is preferably 40 to 100% by volume of the total volume of the base material from the viewpoint of moldability at the time of producing the base material.

The base material (2) may further contain a component other than the heat-resistant resin as long as the desired effect of the present invention can be obtained. For example, as a constituent material of the base material, a filler may be contained in addition to the heat-resistant resin. The filler is, for example, a component that contributes to at least one performance improvement of the hardness, heat transferability and conductivity of the base material. The filler may be one kind or two or more kinds, and examples of the filler include carbon black, Ketjen black, nanocarbon, graphite and the like.

In the present invention, if the content of the filler in the base material is too large, the toughness of the base material may be low and the fixability and separability of the fixing member may be low, and if it is too low, for example, appropriate conductivity may be obtained. The desired effect of the filler, such as imparting sex, may be inadequate. From such a viewpoint, the content of the filler in the base material is preferably 3% by mass or more, more preferably 4% by mass or more, and further preferably 5% by mass or more. From the above viewpoint, the upper limit of the content of the filler in the base material is preferably 30% by mass or less, more preferably 20% by mass or less, and further preferably 10% by mass or less. preferable.

(II. Elastic layer)
The elastic layer (3) constituting the fixing member according to the present invention is a layer having elasticity that contributes to the improvement of the contact property between the surface of the fixing member in the fixing nip portion and the recording medium carrying the unfixed toner image. Yes, for example, it is made of an elastic material.

Examples of elastic materials applicable to the present invention include elastic resin materials, which include silicone rubbers, thermoplastic elastomers and rubber materials. Above all, the elastic material is preferably silicone rubber from the viewpoint of heat resistance in addition to the desired elastic properties.

The above silicone rubber may be used alone or in combination of two or more. Examples of the silicone rubber applicable to the present invention include polyorganosiloxane or a heat-cured product thereof, an addition reaction type silicone rubber described in JP-A-2009-122317, and the like.

As an example of the polyorganosiloxane, dimethylpolysiloxane described in JP-A-2008-255283, in which both ends are sealed with a trimethylsiloxane group and the side chain has a vinyl group, can be mentioned as a typical example.

The thickness of the elastic layer (3) is preferably in the range of 5 to 500 μm, more preferably in the range of 50 to 350 μm, for example, from the viewpoint of sufficiently exhibiting heat transferability and elasticity.

The elastic layer (3) may further contain components other than the elastic resin material within the range in which the desired effect of the present invention can be obtained. For example, the elastic layer may contain a heat-conducting filler for enhancing the heat-conducting property of the elastic layer, in addition to the elastic material. Examples of the material of the filler include silica, metallic silicon, alumina, zinc, aluminum nitride, boron nitride, silicon nitride, silicon carbide, carbon and graphite. The form of the filler is not limited, and is, for example, a spherical powder, an amorphous powder, a flat powder, or a fibrous form.

The content of the elastic resin material in the elastic material constituting the elastic layer is preferably in the range of 60 to 100% by volume, preferably 75 to 100% by volume, from the viewpoint of achieving both heat transferability and elasticity. %, More preferably 80 to 100% by volume.

(III. Surface layer)
The surface layer (4) constituting the fixing member according to the present invention is composed of at least a cured product of a composition containing a perfluoropolyether compound having an alkoxysilane at the molecular terminal and a filler having a hydroxy group on the surface. To.

<Perfluoropolyether compound having alkoxysilane at the molecular end>
The perfluoropolyether compound (hereinafter, also referred to as “PFPE”) in the perfluoropolyether compound having an alkoxysilane at the molecular terminal applied to the present invention is an oligomer or polymer having a perfluoroalkylene ether as a repeating unit.

Examples of repeating unit structures for perfluoroalkylene ethers include repeating unit structures for perfluoromethylene ethers, perfluoroethylene ethers and perfluoropropylene ethers.

Among them, it is preferable that the perfluoropolyether has the repeating structural unit 1 represented by the following formula (a) or the repeating structural unit 2 represented by the following formula (b).

When the PFPE has the repeating structure unit 1 or the repeating structure unit 2, the repetition number m of the repetition structure unit 1 and the repetition number n of the repetition structure unit 2 are integers of 0 or more, respectively, and m + n ≧ 1. be.

Further, when both the repeating structural unit 1 and the repeating structural unit 2 are provided, the repeating structural unit 1 and the repeating structural unit 2 form a random copolymer structure even if the block copolymer structure is formed. May be good.

The alkoxysilyl group having an alkoxysilane at the molecular terminal is not particularly limited, but may be a monoalkoxysilyl group, a dialkoxysilyl group, a trialkoxysilyl group or the like. Usually, in the alkoxysilyl group, the number of carbon atoms of the alkoxy group bonded to the silicon atom is about 1 to 20.

Specific examples of the alkoxysilyl group include a trialkoxysilyl group such as a trimethoxysilyl group and a triethoxysilyl group, a dialkoxyalkylsilyl group such as a dimethoxymethyl group, a diethoxymethyl group and a diethoxyethyl group, and a methoxydimethyl group. Examples thereof include monoalkoxydialkyl groups such as an ethoxydimethyl group and an ethoxydiethyl group, but the present invention is not limited thereto.
The alkoxysilyl group may be present at both ends of the PFPE or only at one end, but in order to exhibit sufficient strength as a surface layer, it is preferable that the alkoxysilyl group is present at both ends. ..

The perfluoropolyether compound having an alkoxysilane at the molecular terminal applied to the present invention is preferably a compound represented by the following general formula (c).

General formula (c)
BA-CF ₂ O (CF ₂ CF ₂ O) _m (CF ₂ O) _n CF ₂ -AB
In the above general formula (c), A represents a linking group, B represents an alkoxysilyl group, m and n each represent an integer of 0 or more, and m + n ≧ 1.

In the above general formula (c), the alkoxysilyl group represented by B is the same as the alkoxysilyl group described above, and the compound has an alkoxysilyl group at both ends.

M and n in the equation are integers of 0 or more, respectively, and m + n ≧ 1. The m is preferably 2 to 20, more preferably 4 to 15. Further, the n is preferably 2 to 20, more preferably 4 to 15.

Further, a mixture of a perfluoropolyether compound in which both ends of the molecular structure are alkoxysilanes and a perfluoropolyether compound in which one end of the molecular structure is alkoxysilanes may be used. The proportion of the perfluoropolyether compound having alkoxysilanes at both ends in the mixture is preferably in the range of 80 to 100% by mass. If the proportion of the perfluoropolyether compound having alkoxysilanes at both ends is less than 80% by mass, the curability of the surface layer may be insufficient.

The weight average molecular weight Mw of the perfluoropolyether compound having an alkoxysilane at the molecular end is preferably in the range of 100 to 8000, and more preferably in the range of 500 to 5000.

Examples of commercially available products of perfluoropolyether compounds having an alkoxysilane at the molecular end include "Fluorolink S10" manufactured by Solvay, which has a triethoxysilyl group at both ends ("FLUOROLINK" is a registered trademark of the company). Be done.

<filler>
The filler contained in the surface layer is a filler having a hydroxy group on the surface. As long as such a filler suppresses cross-linking and entanglement between perfluoropolyether chains by forming a primary bond with the alkoxysilane terminal of the perfluoropolyether compound, the hydroxy group on the surface thereof is used. There is no particular limitation. Suitable fillers in the present invention include hydrophilic metal oxide fine particles having a hydroxy group on the surface and cellulose nanofibers.

Examples of the metal oxide fine particles having a hydroxy group on the surface include silica, titanium oxide, zinc oxide, alumina (aluminum oxide), tin oxide, antimony oxide, indium oxide, bismuth oxide, zirconium oxide, and the like. Titanium oxide, tin oxide and the like are preferable. One type of these metal oxide particles may be used alone, or two or more types may be mixed and used.

The particle size of the metal oxide fine particles is not particularly limited, but is usually preferably 5 nm or more and 10 μm or less, and more preferably 30 nm or more and 1.0 μm or less. If the particle size is too small, such as less than 5 nm, it becomes difficult to disperse, and if the particle size is larger than 10 μm, the toner temporarily fits into the uneven structure formed by the particles and is fixed in an unintended place. This is not preferable because the surface of the fixing toner is uneven and visible light is scattered, resulting in a low-gloss image. The particle size can be determined using a known particle size distribution device.

The cellulose nanofibers used as a filler having a hydroxy group are not particularly limited, but the fiber width is usually preferably in the range of 1 to 200 nm, and more preferably in the range of 1 to 100 nm. preferable. The fiber length of the cellulose nanofibers is usually preferably in the range of 1 to 200 μm, more preferably in the range of 1 to 100 μm. When the fiber width and fiber length of the cellulose nanofibers are within the above ranges, the surface of the fixing toner is not uneven and the gloss is not lowered, which is preferable.

Further, the filler having a hydroxy group preferably has a degree of hydrophobicity in the range of 0 to 20%. When the degree of hydrophobicity is 20% or less, it is considered that the amount of hydroxy groups required for exhibiting the effect of the present invention is secured.

The degree of hydrophobicity referred to in the present invention is a value measured by the following method.

To 0.5 g of the filler, 100 mL of a mixed solution in which the ratio of water and methanol was changed was added, shaken, and allowed to stand overnight. The degree of hydrophobicity.

The amount of the filler contained in the surface layer is not particularly limited, but is preferably in the range of 5 to 30% by volume of the total surface volume, and more preferably in the range of 5 to 20% by volume. When the amount of the filler is 5% by volume or more, it is possible to suppress cross-linking and entanglement between perfluoropolyether chains and improve the molecular mobility of the solid surface of the surface layer. Further, if the amount of the filler is 30% by volume or less, there is no possibility of impairing the properties required for the surface layer of the fixing member.

The amount of the filler contained in the surface layer of the fixing member can be confirmed by the following method. For example, in the case of a filler having high heat resistance to a matrix which is an organic substance such as metal oxide fine particles, it can be calculated from the residue when the temperature is raised to 500 ° C. by thermogravimetric analysis. As another method, it can be calculated by creating a cross section with a microtome or the like and analyzing an image observed with an electron microscope or a laser microscope.

Further, the composition constituting the surface layer includes the perfluoropolyether compound having an alkoxysilane at the molecular terminal and the filler having a hydroxy group on the surface, as long as the characteristics of the surface layer in the present invention are not impaired. Ingredients may be contained. Such other components include perfluoropolyether compounds having a functional group other than the alcoholicyl group at the end, other resins such as PFA, compounds other than the perfluoropolyether having an alcoholicylyl group, and alkoxysilyl groups. A catalyst for a dehydration condensation reaction, a fine particle material, an additive, etc., which can be generally contained in the surface layer of a fixing member.

Further, an aluminum chelating agent can be applied. Specific examples of the aluminum chelating agent include aluminum tris (acetylacetoneate), aluminumtris (ethylacetate acetate), aluminum monoacetylacetonate bis (ethylacetate acetate), aluminum monoacetylacetonate bisoleylacetacetate, and ethylacetate acetate. Examples thereof include aluminum diisopropylate and alkylacetate acetate aluminum diisopropyrate.

The thickness of the surface layer can be appropriately determined from the range in which the performance is exhibited, and is, for example, within the range of 5 to 100 μm from the viewpoint of heat transfer, follow-up to deformation of the elastic layer, and development of releasability. It is preferably in the range of 5 to 50 μm, more preferably in the range of 5 to 30 μm, and even more preferably in the range of 5 to 30 μm.

<< Image forming device >>
A fixing member, which is a typical example of an electrophotographic member having a surface layer formed by using the surface layer forming coating liquid produced by the method for producing a surface layer forming coating liquid of the present invention, is incorporated into an electrophotographic image forming apparatus. Can be done.

An example of a typical image forming apparatus will be described with reference to the figures.

FIG. 3 is a schematic view showing an example of the overall configuration of an image forming apparatus applicable to the present invention.

The image forming apparatus (10) shown in FIG. 3 is an intermediate transfer type color image forming apparatus using an electrophotographic process technique, and is mainly an automatic document conveying unit (20), a scanner unit (30), and an image forming apparatus. It is configured to include a unit (40), a paper feeding unit (50), a storage unit (60), an operation display unit (70), a control unit) 100) and the like.

The automatic document transport unit (20) is configured to include a mounting tray on which the document (D) is placed, a mechanism for transporting the document (D), a transport roller, and the like, and transports the document (D) to a predetermined transport path. do.

The scanner unit (30) is configured to include an optical system such as a light source and a reflecting mirror, and irradiates a document (D) transported along a predetermined transport path or a document (D) placed on a platen glass with a light source. , Receives reflected light. Further, the scanner unit (30) converts the received reflected light into an electric signal and outputs it to the control unit (100).

The image forming section (40) includes a yellow image forming section (Y), a magenta image forming section (M), a cyan image forming section (C), a black image forming section (K), an intermediate transfer belt (T), and a fixing device ( F) etc. are provided.

In addition, a photoconductor drum (41), a charging device (42), an exposure device (43), a developing device (44), a primary transfer roller (45), an intermediate transfer belt (T), and a secondary transfer roller (46). Etc., but the detailed description of the configuration will be omitted.

As shown in FIG. 3, the fixing device (F) including the fixing member having a surface layer according to the present invention is mainly a heating transfer roller (conveying roller, F1) arranged on the lower surface side of the paper (P). A fixing roller (first roller, F2) arranged on the upper surface side, a heating roller (second roller, F3) arranged above the fixing roller (F2), and a fixing belt which is a fixing member according to the present invention. (F4) and the like are provided. The fixing device (F) heats and applies the paper (P) by passing the paper (P) through the nip portion formed by heating and pressing the heat transport roller (F1) and the fixing roller (F2). The transferred toner image is fixed on the paper (P) by pressing, and the paper (P) is transported downstream in the transport direction.

The heating transfer roller (F1) is formed in a cylindrical shape by rubber, and has a high output heater inside like the heating roller (F3). The heat transfer roller (F1) rotates in the forward direction with respect to the transfer direction of the paper (P) to heat and pressurize the non-fixed surface of the transferred paper (P).

The fixing device provided with the fixing member having a surface layer according to the present invention can be configured in the same manner as a known fixing device having a structure corresponding to the form of the fixing member. For example, when the fixing member is the fixing belt, it is preferable that the fixing device has a known structure for realizing biaxial tension belt fixing, pad pressing belt fixing, IH belt fixing, and the like. ..

Details of the image forming apparatus applicable in the present invention include, for example, Japanese Patent Application Laid-Open No. 2017-173445, 2017-194550, 2018-4714, 2018-5016, 2018-25691. Refer to the image forming apparatus and fixing apparatus described in JP-A, 2018-25691, 2018-36449, 2018-36587, 2018-54758, 2018-66768 and the like. can do.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto. Although the display of "parts" or "%" is used in the examples, it represents "parts by mass" or "% by mass" unless otherwise specified. Unless otherwise specified, each operation was performed at room temperature (25 ° C.).

<< Preparation of coating liquid for surface layer formation >>
[Preparation of coating liquid 1 for surface layer formation]
(1) Preparation of dispersion liquid A (step 1)
In an open container, as a perfluoropolyether compound (PFPE) having an alkoxysilane terminal, 15 parts by mass of Fluorolink S10 (PFPE monomer manufactured by Solvay, having triethoxysilane at both ends) and 0.30 of ion-exchanged water are added. The mass part was added and mixed, and the opening of the open container was covered with the clean wiper "Bencot", which is a long fiber non-woven fabric manufactured by Asahi Kasei, and the stirring time (T) was 25 ° C. for 72 hours to disperse. Liquid A was prepared.

(2) Preparation of mixed liquid 1 with dispersion liquid A and filler (step 2)
Next, 59 parts by mass of tetrahydrofuran was added and dissolved in the above-prepared dispersion A, and then, as a filler having a hydroxy group, rutyl-type titanium oxide manufactured by TAYCA Corporation (abbreviation: JR, average primary particle diameter: 0.27 μm). , Surface treatment: None) was mixed in an amount of 7.4 parts by mass to prepare a mixed solution 1.

(3) Preparation of dispersion liquid B (step 3)
The above-prepared mixed liquid 1 was dispersed using an ultrasonic homogenizer to prepare a dispersion liquid B, which was used as a surface layer forming coating liquid 1.

[Preparation of coating liquid 2 for surface layer formation]
In the preparation of the dispersion liquid A in step 1 of the coating liquid 1 for forming the surface layer, 0.30 parts by mass of ion-exchanged water was added to an aluminum chelate compound (aluminum tris (acetylacetonate), abbreviation: A (W), Kawaken Fine Chemicals). Same as above, except that 0.075 parts by mass of A (W)) and 0.15 parts by mass of ion-exchanged water were changed, and the stirring time (T) at 25 ° C. was changed from 72 hours to 10 hours. The coating liquid 2 for forming the surface layer was prepared.

[Preparation of coating liquid 3 for surface layer formation]
In the preparation of the dispersion liquid A in step 1 of the surface layer forming coating liquid 2, the surface layer forming coating liquid 3 was prepared in the same manner except that the stirring time (T) at 25 ° C. was changed from 10 hours to 1 hour. ..

[Preparation of coating liquid 4 for surface layer formation]
In the preparation of the dispersion liquid A in step 1 of the surface layer forming coating liquid 1, the surface layer forming coating liquid 4 was prepared in the same manner except that the stirring time (T) at 25 ° C. was changed from 72 hours to 192 hours. .. In step 2 of the coating liquid 4 for forming the surface layer, a very small amount of transparent gel particles could be visually observed at the stage where the dispersion liquid A was dissolved in tetrahydrofuran. Therefore, Advantech's qualitative filter paper No. The transparent gel particles were removed by natural filtration using 101.

[Preparation of coating liquid 5 for surface layer formation]
In the preparation of the dispersion liquid A in step 1 of the surface layer forming coating liquid 2, the surface layer forming coating liquid 5 was prepared in the same manner except that the stirring time (T) at 25 ° C. was changed from 10 hours to 96 hours. .. In step 2 of the coating liquid 5 for forming the surface layer, a very small amount of transparent gel particles could be visually observed at the stage where the dispersion liquid A was dissolved in tetrahydrofuran. Therefore, Advantech's qualitative filter paper No. The transparent gel particles were removed by natural filtration using 101.

[Preparation of coating liquid 6 for surface layer formation]
In the preparation of the dispersion liquid A in the step 1 of the coating liquid 1 for forming the surface layer, the surface layer is formed in the same manner except that the steps 1 to 3 are continuously performed without providing the stirring time (T) at 25 ° C. A coating liquid 6 for use was prepared.

[Preparation of coating liquid 7 for surface layer formation]
In the preparation of the dispersion liquid A in the step 1 of the coating liquid 2 for forming the surface layer, the surface layer is formed in the same manner except that the steps 1 to 3 are continuously performed without providing the stirring time (T) at 25 ° C. A coating liquid 7 for use was prepared.

[Preparation of coating liquid 8 for surface layer formation]
In the preparation of the dispersion liquid A in step 1 of the coating liquid 2 for forming the surface layer, a closed container is used instead of the open container, and the gas is circulated (updated) in the space inside the container for 10 hours, which is the stirring time (T). ) Was not performed, and the coating liquid 8 for forming the surface layer was prepared in the same manner.

<< Fabrication of fixing belt >>
[Manufacturing of fixing belt 1]
A cylindrical core metal made of stainless steel having an outer diameter of 99 mm was adhered to the inside of a belt base material made of a thermosetting polyimide resin having an inner diameter of 99 mm, a length of 360 mm, and a thickness of 70 μm. Next, a cylindrical mold was placed on the outside of the belt base material to coaxially hold the core metal and the cylindrical mold, and a cavity was formed between the two.

Next, the silicone rubber material A was injected into the cavity and cured by heating to form an elastic layer made of the silicone rubber A having a thickness of 200 μm. The silicone rubber material A is a composition obtained by mixing 100 parts by mass of dimethylpolysiloxane having a vinyl group in the side chain and 15 parts by mass of silica.

Next, the endless laminate of the belt base material and the elastic layer produced as described above was stretched on a spiral coating device and rotated to perform corona treatment.

Next, the surface layer forming coating liquid 1 prepared above was applied to the outer peripheral surface of the endless laminate by a spiral coating method to form a coating film using the surface layer forming coating liquid 1. The formed coating film was heat-dried at 100 ° C. for 1 hour, then heated to 150 ° C., and then humidified at 50 ° C. for 4 hours in an environment of 85% RH to a thickness of 10 μm. A fixing belt 1 was produced in which a surface layer was formed and a belt base material, an elastic layer, and a surface layer were laminated in this order.

[Manufacturing of fixing belts 2 to 8]
In the production of the fixing belt 1, the fixing belts 2 to 8 were produced in the same manner except that the surface layer forming coating liquid 1 used for forming the surface layer was changed to the surface layer forming coating liquids 2 to 8, respectively.

<< Evaluation of coating liquid for surface layer formation >>
[Evaluation of dispersion stability]
After preparing the fixing belt using each of the above surface layer forming coating liquids, visually observe the bottom of the kettle in which the coating liquid is stored to confirm the presence or absence of white precipitate generation, and stabilize the dispersion of the coating liquid according to the following criteria. Gender was evaluated.

◯: No sediment was observed at the bottom of the kettle, and there was no agglomerate on the formed surface layer. Δ: A very small amount of precipitate was observed at the bottom of the kettle, but the formed surface layer. No agglomerates are generated, and the quality is practically acceptable. ×: A large amount of white precipitates are found at the bottom of the kettle, and agglomerates are scattered even in the formed surface layer, which is practically acceptable. The quality in question.

[Evaluation of gelation resistance]
In the preparation of each of the above surface layer forming coating liquids, the presence or absence of gelled substances in the solution at the stage where tetrahydrofuran was added and dissolved in the dispersion liquid A prepared in step 2 was visually observed, and gelation resistance was observed according to the following criteria. Evaluation was performed.

◯: No gelation is observed △: A very small amount of gelation is observed, but the gelation can be easily removed by filtration treatment ×: A large amount of gelation is generated. , The filtration process causes clogging, it is difficult to remove the gelled product, and the amount of solid content changes. I can't.

<< Evaluation of fixing belt >>
[Evaluation of image quality: Presence or absence of image defects]
Each of the above-produced fixing belts 1 to 8 was attached to a full-color copying machine "bizhub PRESS C1070" (manufactured by Konica Minolta Co., Ltd., "bizhub" is a registered trademark of the company). As a recording medium, "mondi color copy A3 basis weight: 90 g / m ² " was used. The surface temperature of the fixing belt was 180 ° C. A two-component developer is used as the toner, and the volume average particle size of the toner matrix particles is 6.5 μm.

The amount of magenta and yellow toner adhered to the recording medium is adjusted to 4 g / m ² for each color, and a solid image of red, which is a secondary color, is output, and the presence or absence of image defects in the formed solid image is specified. Specifically, the presence or absence of punctate defects and a feeling of roughness was visually observed, and the image quality was evaluated according to the following criteria.

◯: No punctate defects or graininess in the formed solid image Δ: Extremely weak punctate defects or graininess are observed in the formed solid image, but the quality is practically acceptable. X: The formed solid image has strong punctate defects and a rough feeling, and the quality is not practical. The results obtained as described above are shown in Table I.

As is clear from the results shown in Table I, a perfluoropolyether compound having an alkoxysilane at the molecular end and a filler having a hydroxy group on the surface are used, and a dispersion liquid containing the perfluoropolyether compound is placed in an open system container. It can be seen that the coating liquid for surface layer formation of the present invention prepared in 1 above and prepared with a time lag until the filler is added to the dispersion liquid is excellent in dispersion stability and gelation resistance as compared with the comparative example. .. Further, the fixing belt provided with the surface layer formed by using the coating liquid for forming the surface layer of the present invention is excellent in image quality because there is no occurrence of punctate defects or a feeling of roughness in the formed image as compared with the comparative example. I understand. Further, it was confirmed that the fixing belt provided with the surface layer formed by using the coating liquid for forming the surface layer of the present invention is excellent in releasability from the recording medium at the time of image formation.

2 Base material 3 Elastic layer 4 Surface layer 10 Image forming device 20 Automatic document transfer part 30 Scanner part 40 Image forming part 41 Photoreceptor drum 42 Charging device 43 Exposure device 44 Developing device 45 Primary transfer roller 46 Secondary transfer roller 47, 48 Cleaning Equipment T Intermediate transfer belt F Fixing device F1 Heat transfer roller (transfer roller)
F2 fixing roller (first roller)
F3 heating roller (second roller, heating part)
1, F4 fixing belt F5 sensor F6 roller moving part F7 regulation member 50 paper feeding part 60 storage part 70 operation display part 100 control part (area setting part, movement amount setting part, roller control part)

Claims (5)

A method for producing a coating liquid for forming a surface layer of an electrophotographic member consisting of at least a base material and a surface layer.
At least, step 1 of preparing a dispersion liquid A containing a perfluoropolyether compound having an alkoxysilane at the molecular terminal and water, and
Step 2 of adding a filler having a hydroxy group on the surface to the dispersion liquid A to prepare a mixed liquid, and
It also has a step 3 of dispersing the dispersion liquid A and the mixed liquid containing the filler to prepare the dispersion liquid B, and
A method for producing a coating liquid for forming a surface layer, which comprises providing a time interval for stirring the dispersion liquid A in an open state between the start time of the step 1 and the start time of the step 2. The method for producing a coating liquid for forming a surface layer according to claim 1, wherein the electrophotographic member is a fixing member. The method for producing a coating liquid for forming a surface layer according to claim 1 or 2, wherein the time interval between the step 1 and the step 2 is 1 hour or more. The method for producing a coating liquid for forming a surface layer according to any one of claims 1 to 3, wherein the filler having a hydroxy group on the surface is hydrophilic metal oxide fine particles. A method for manufacturing an electrophotographic member consisting of at least a base material and a surface layer.
At least, step 1 of preparing a dispersion liquid A containing a perfluoropolyether compound having an alkoxysilane at the molecular terminal and water, and
Step 2 of adding a filler having a hydroxy group on the surface to the dispersion liquid A to prepare a mixed liquid, and
Step 3 to prepare the dispersion liquid B by dispersing the mixture liquid containing the dispersion liquid A and the filler.
It has a step 4 of applying and curing the coating liquid for forming a surface layer containing the dispersion liquid B on the base material to form a surface layer, and also
A method for manufacturing an electrophotographic member, which comprises providing a time interval for stirring the dispersion liquid A in an open state between the start time of the step 1 and the start time of the step 2.

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