JP2020140185A - Fixing member, fixing device, and electrophotographic image forming device - Google Patents

Abstract

To provide a fixing member which maintains superior toner releasability even after prolonged use.SOLUTION: A fixing member is provided, comprising a base layer, an elastic layer, and a surface layer arranged in the described order, where the elastic layer contains a silicone rubber and the surface layer is a single layer containing a fluorine resin and a fluorine oil having a perfluoropolyether structure. Deposits containing a certain mass of the fluorine oil is detected from the fixing member through a prescribed measurement made using a quartz crystal microbalance (QCM) sensor.SELECTED DRAWING: Figure 3

Description

The present invention relates to a fixing member, a fixing device, and an electrophotographic image forming device.

In a fixing device used in an electrophotographic image forming apparatus (hereinafter, also referred to as an "image forming apparatus") such as a copying machine or a laser printer, a pair of heated rollers and rollers, a film and a roller, a belt and a roller, and a belt and a belt are used. , Etc. are pressed against each other. Then, a recording medium such as paper holding an image formed by the unfixed toner is introduced into the pressure contact portion (hereinafter, referred to as “fixing nip portion”) formed between the rotating bodies to introduce the unfixed toner. The image is fixed on the recording medium by heating and melting. The rotating body in contact with the unfixed toner image on the recording medium is called a fixing member, and is called a fixing roller, a fixing film, or a fixing belt according to its form.
In the fixing member for electrophotographic, a fluororesin, specifically, a fluororesin, specifically, is used to prevent adhesion of toner to a surface layer (hereinafter, referred to as “surface layer”) constituting an outer surface that comes into contact with toner. for example, tetrafluoroethylene - and perfluoroalkyl vinyl ether _{(-CF 2 -CF (ORf) -} ) (-C 2 F 4) copolymers of (. hereinafter, also referred to as "PFA") surface layer containing the May be used. Here, "Rf" represents a perfluoroalkyl group.
In recent years, the paper media used for forming electrophotographic images have been diversified, and for example, it is required to support thin paper having a basis weight of 52 g / m ² . However, since such thin paper has low rigidity, in the conventional fixing member, the molten toner at the time of heat fixing may adhere to the surface of the surface layer, and the thin paper may be wrapped around the fixing member. In order to stably form an electrophotographic image on thin paper, it is necessary to give the surface of the fixing member a higher toner releasability.
Here, Patent Document 1 has a layer containing a fluoropolymer such as PFA covalently bonded to a compound having a perfluoropolyether (hereinafter, also referred to as “PFPE”) chain or a perfluoroalkyl chain on the outermost surface. A liquid-repellent film having the liquid-repellent film and a fixing member provided with the liquid-repellent film are disclosed.

JP-A-2018-22056

"Journal of the Japan Adhesion Association", Japan Adhesion Society, 1972, Vol. 8, No. 3, p. 131-141

According to the study by the present inventors, it was confirmed that the fixing member according to Patent Document 1 has excellent toner releasability. Therefore, the present inventors have studied a fixing member in which a liquid-repellent film according to Patent Document 1 is provided as a surface layer on an elastic layer containing silicone rubber. However, as a result of long-term use, the toner releasability of the outer surface of the fixing member deteriorates, and when forming an electrophotographic image on the thin paper as described above, the thin paper may be wrapped around the fixing member. there were.
One aspect of the present invention is to provide a fixing member capable of maintaining high toner releasability for a long period of time. Further, another aspect of the present invention is aimed at providing a fixing device that contributes to long-term stable formation of a high-quality electrophotographic image. Furthermore, another aspect of the present invention is aimed at providing an electrophotographic image forming apparatus capable of stably forming a high-quality electrophotographic image for a long period of time.

According to one aspect of the present invention, the fixing member for electrophotographic having a base layer, an elastic layer, and a surface layer on the elastic layer in this order in the thickness direction.
The elastic layer contains silicone rubber and contains
The surface layer consists of a single layer
The surface layer contains a fluororesin and a fluorine oil having a perfluoropolyether structure, and the fixing member is provided with a fixing member satisfying the requirements (i) and the requirement (ii):
(I) After cleaning a predetermined position on the first surface of the measurement sample including the entire thickness portion of the surface layer collected from the fixing member on the side opposite to the side facing the base layer, the measurement sample is cleaned. The unit area of the detection surface when the detection surface of the quartz crystal microbalance (QCM) sensor is pressed against the position at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. The mass P11 of the deposit containing the fluorine oil having a perfluoropolyether structure adhering to (1 cm ² ) is 1.0 × 10 ² ng or more and 1.0 × 10 ⁴ ng or less;
(Ii) For the measurement sample subjected to the treatment specified in the requirement (i), after cleaning the position, the measurement sample was placed in an environment at a temperature of 180 ° C. for 120 seconds, and then the quartz crystal microbalance was placed in the position. QCM) Perfluoropolyether structure that adheres to the unit area (1 cm ² ) of the detection surface when the detection surface of the sensor is pressed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. The mass P12 of the deposit containing the fluorine oil having the above is 0.5 × P11 or more and 1.2 × P11 or less.

Further, according to another aspect of the present invention, the fixing member for electrophotographic having a base layer, an elastic layer, and a surface layer on the elastic layer in this order in the thickness direction.
The elastic layer contains silicone rubber and contains
The surface layer consists of a single layer
The surface layer contained a fluororesin and a fluorine oil having a perfluoropolyether structure, and faced the base layer for a measurement sample including the entire thickness portion of the surface layer collected from the fixing member. When the detection surface of the quartz crystal microbalance (QCM) sensor is pressed against the first surface on the side opposite to the side at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec, the detection surface The mass of the deposit containing fluorine oil having a perfluoropolyether structure, which adheres to the unit area (1 cm ² ) of the above, is P11 (ng).
With respect to the second surface of the measurement sample facing the base layer, the detection surface of the quartz crystal microbalance (QCM) sensor was placed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. When the mass of the deposit containing fluorine oil having a perfluoropolyether structure, which adheres to the unit area (1 cm ² ) of the detection surface when pressed, is P21 (ng), the fixing member having P21> P11 Provided.
Further, according to another aspect of the present invention, there is provided a fixing device including the above-mentioned fixing member and a heating means for the fixing member. Furthermore, according to another aspect of the present invention, an electrophotographic image forming apparatus including the above-mentioned fixing device is provided.

According to one aspect of the present invention, it is possible to obtain a fixing member capable of maintaining excellent toner releasability even in long-term use. Further, according to another aspect of the present invention, it is possible to obtain a fixing device that contributes to the stable formation of a high-quality electrophotographic image. Furthermore, according to another aspect of the present invention, it is possible to obtain an electrophotographic image forming apparatus capable of stably forming a high-quality electrophotographic image for a long period of time.

6 is a surface observation image of the fixing member according to the first embodiment. It is a surface observation image of the fixing member described in Comparative Example 4. It is sectional drawing of the fixing belt (A) and the fixing roller (B) which are an example of this invention. It is sectional drawing of the fixing apparatus using the fixing belt which concerns on this invention. It is sectional drawing of the fixing apparatus using the fixing roller which concerns on this invention. It is a schematic cross-sectional schematic diagram which shows one aspect of the electrophotographic image forming apparatus of this invention. It is the sectional schematic view (A) of the fixing member which concerns on this invention, and the schematic diagram (B) of the amount of fluorine oil of a surface layer.

According to the study by the present inventors, it was confirmed that the fixing member according to Patent Document 1 has excellent toner releasability. Therefore, the present inventors have studied a fixing member in which the liquid-repellent film according to Patent Document 1 is provided as a surface layer on an elastic layer containing silicone rubber. However, as a result of long-term use, the toner releasability of the outer surface of the fixing member deteriorates, and when forming an electrophotographic image on the thin paper as described above, the thin paper may be wrapped around the fixing member. there were.
It is considered that such a decrease in toner releasability over time is due to wear of the surface layer due to repeated deformation of the surface layer due to deformation of the elastic layer at the fixing nip portion. It is considered that this is because the compound having the perfluoropolyether chain or the perflooloalkyl chain, which contributes to the improvement of the toner releasability, is lost from the outer surface of the fixing member.
The present inventors have repeated studies for the purpose of obtaining a fixing member capable of maintaining excellent toner releasability even after long-term use. As a result, it has been found that the fixing member according to the above-described embodiment can achieve such an object well. Hereinafter, the fixing member according to each aspect will be described in detail.

The fixing member according to one aspect of the present invention has a base layer, an elastic layer, and a surface layer on the elastic layer in this order in the thickness direction. The elastic layer contains silicone rubber, the surface layer is composed of a single layer, and the surface layer is composed of a fluororesin and a fluorine oil having a perfluoropolyether structure (hereinafter, also simply referred to as "fluorine oil"). ,including.
Further, the fixing member satisfies the following requirements (i) and (ii).
Requirement (i): For a measurement sample including the entire thickness portion of the surface layer collected from the fixing member, a predetermined position on the first surface opposite to the side facing the base layer is cleaned. .. After that, the detection surface of the quartz crystal microbalance (QCM) sensor is pressed against the position at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. At this time, the mass P11 of the deposit containing fluorine oil adhering to the unit area (1 cm ² ) of the detection surface is 1.0 × 10 ² ng or more and 1.0 × 10 ⁴ ng or less.
Requirement (ii): The position of the measurement sample subjected to the treatment specified in the above requirement (i) is cleaned. After that, it is placed in an environment at a temperature of 180 ° C. for 120 seconds, and then the detection surface of the QCM sensor is pressed at the position at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. At this time, the mass P12 of the deposit containing fluorine oil adhering to the unit area (1 cm ² ) of the detection surface is 0.5 × P11 or more and 1.2 × P11 or less.

The treatment specified in the above requirement (i) may refer to the fluorine oil contained inside the surface layer as the first surface (hereinafter, referred to as "outer surface") on the side opposite to the side facing the base layer of the surface layer. ) Is positioned as a process to shift to. That is, the pressing conditions (pressure, temperature, pressurizing time) on the outer surface in the process specified in (i) above are the outer surface of the surface layer of the fixing member at the fixing nip during heat fixing in the electrophotographic image forming process. It is set as corresponding to the condition to be added to.
Further, the amount of fluorine oil present on the outer surface of the fixing member can be measured by using a crystal oscillator. The crystal unit has the sensitivity to measure masses on the order of nanograms. The crystal oscillator has a structure in which both side surfaces of a crystal plate of a crystal are sandwiched between metal electrodes, and when an AC electric field is applied to the metal electrodes on both sides, the crystal oscillator vibrates at a constant frequency (resonance frequency) due to a reverse voltage drop of the crystal. Then, when a small amount of substance adheres to the metal electrode, the resonance frequency decreases in proportion to the amount of adhesion. By utilizing this phenomenon, the crystal unit can be used as a microbalance.
The amount of change in the frequency of the crystal unit and the mass of the adhering substance on the metal electrode follow the following Sauerbury formula (formula (a)).

(ΔF: frequency change, Δm: mass change amount, F ₀ : fundamental frequency, ρ _Q : crystal density, μ _Q : crystal shear stress, A: electrode area)
This measuring method is also referred to as a Quartz Crystal Microbalance (QCM) method.

Further, "cleaning" according to the above requirement (i) means that a non-woven fabric impregnated with ethanol is placed at the position, and a load of 20 kPa is applied on the non-woven fabric to reciprocate the position 10 times. Subsequently, the non-woven fabric is impregnated with toluene, the non-woven fabric is placed in the position, and a load of 20 kPa is applied on the non-woven fabric to reciprocate the position 10 times. As a result, the fluorine oil existing on the outer surface is mechanically removed. On the other hand, ethanol and toluene do not dissolve PFPE, so that PFPE existing in the surface layer is not eluted.
Therefore, in the above requirement (i), the amount of the fluorine oil existing inside the surface layer exuded to the first surface of the surface layer by the pressing treatment specified in the requirement (i) is 1.0. It means that it is × 10 ² ng or more and 1.0 × 10 ⁴ ng or less. By setting P11 within the above numerical range, adhesion of toner to the outer surface of the fixing member during heat fixing can be significantly suppressed. As a result, it is possible to prevent the occurrence of toner offset during heat fixing, and it is also possible to prevent the occurrence of offset due to the cohesive failure of the toner due to the viscosity of the fluorine oil. Further, P11 is more preferably 1.0 × 10 ² ng or more and 5.0 × 10 ³ ng or less.
As a method for preparing a measurement sample from the fixing member including the entire thickness portion of the surface layer, for example, when the fixing member has a structure in which an elastic layer and a surface layer are sequentially laminated on a base layer, an elastic layer is used. A method of cutting out a laminated body of the surface layer and removing the elastic layer from the laminated body can be mentioned. As a method of removing the elastic layer from the laminated body, a method of peeling the surface layer from the interface portion with the elastic layer with a knife, or a method in which the fluororesin in the surface layer is not dissolved and the resin component in the elastic layer can be dissolved. Examples thereof include a method of dissolving and removing only the elastic layer using a solvent. For example, when the elastic layer contains silicone rubber, only the elastic layer can be dissolved and removed from the laminate by using a resin dissolving agent (trade name: e-solve 21RS, manufactured by Kaneko Kagaku Co., Ltd.).

Next, the treatment according to the requirement (ii) is performed on the measurement sample in which the fluorine oil contained in the surface layer is transferred to the first surface of the surface layer by the treatment according to the requirement (i). Purification is performed to remove the fluorine oil that has migrated to the first surface by the treatment according to the above. Then, after being placed in a predetermined environment, the treatment is for transferring the fluorine oil from the inside of the measurement sample to the first surface. Here, "cleaning" refers to the same operation as "cleaning" in the requirement (i). Then, in the fixing member according to this aspect, when the mass of the deposit containing fluorine oil adhering to the unit area of the detection surface of the QCM sensor when the process according to the requirement (ii) is performed is P12, P12 is It is 0.5 times or more and 1.2 times or less of P11. This means that even after the fluorine oil transferred to the outer surface by the treatment according to the above requirement (i) is removed, the first surface of the surface layer has an appropriate amount such that excellent toner releasability can be exhibited. This means that fluorine oil can migrate from the inside of the surface layer to the outside surface.
That is, in the fixing member satisfying the above requirements (i) and the requirement (ii), even if the fluorine oil on the outer surface is once consumed in one heat fixing step, the fluorine oil is supplied to the outer surface from the inside of the surface layer. High toner releasability can be maintained for a long period of time.
For the pressing process according to the above requirements (i) and (ii), for example, a tack tester (trade name: TAC-1000, manufactured by Resca) can be used. Specifically, a crystal oscillator is placed on the stage of the testing machine. On the other hand, the measurement sample including the entire thickness portion of the surface layer collected from the fixing member is fixed to the probe of the testing machine so that the first surface of the measurement sample faces the crystal oscillator. Next, the probe is brought close to the stage portion to press the first surface of the measurement sample against the crystal unit. The pressing conditions are as follows.
・ Pressure: 0.4 MPa,
・ Pressing time: 50 msec,
・ Constant push mode,
-Pressing and pulling speed: 1.0 mm / sec,
-Probe set temperature: 180 ° C.

1. 1. Fixing member FIGS. 3A and 3B are cross-sectional views showing different aspects of the fixing member according to the present invention. FIG. 3A is a fixing member having an endless belt shape (hereinafter, also referred to as “fixing belt 11”), and FIG. 3B is a roller-shaped fixing member (hereinafter, also referred to as “fixing roller 12”). ).
The fixing member according to FIGS. 3 (A) and 3 (B) has a base layer 13, an elastic layer 14 covering the outer surface thereof, and a surface opposite to the side facing the base layer of the elastic layer. It has a coated surface layer 15. The surface layer 15 may be adhered to the surface of the elastic layer 14 on the side opposite to the base layer by an adhesive layer (not shown).
FIG. 7A shows a first surface (outer surface) of the base layer 13, the elastic layer 14, the surface layer 15, and the surface layer 15 of the fixing member according to this embodiment, which is opposite to the side facing the base layer. It is sectional drawing which shows the relationship between 15a and the 2nd surface 15b on the side which faces a base layer. FIG. 7B shows that in the surface layer 15, when the mass P11 of the fluorine oil on the first surface and the mass P21 of the fluorine oil on the second surface are compared, P21 is larger than P11.

(1) Base layer As the material of the base layer 13, metals and alloys such as aluminum, iron, stainless steel and nickel, and heat-resistant resins such as polyimide are used.
In the fixing belt 11, a base material having an endless belt shape may be used as the base layer 13. Examples of the material of the base layer 13 in this case include those having excellent heat resistance such as nickel, stainless steel, and polyimide. The thickness of the base layer 13 is not particularly limited, but is preferably 20 μm or more and 100 μm or less from the viewpoint of strength, flexibility, and heat capacity.
In the fixing roller 12, for example, a solid or hollow core metal is used as the base layer 13. Examples of the material of the core metal include metals or alloys such as aluminum, iron, and stainless steel. When a hollow core metal is used, it is possible to provide a heat source inside.
The outer surface of the base layer 13 may be surface-treated in order to impart adhesiveness to the elastic layer 14. For the surface treatment, one or a plurality of types of physical treatment such as blasting treatment, wrapping treatment and polishing, oxidation treatment, coupling agent treatment and chemical treatment such as primer treatment can be used.
When the elastic layer 14 containing silicone rubber is provided on the surface of the base layer 13, it is preferable to apply a primer treatment to the surface of the base layer 13 in order to improve the adhesiveness between the base layer 13 and the elastic layer 14. Examples of the primer used for the primer treatment include a paint in which a silane coupling agent, a silicone polymer, a hydrogenated methylsiloxane, an alkoxysilane, a reaction accelerating catalyst, and a colorant such as red iron oxide are appropriately mixed and dispersed in an organic solvent. Be done.
The primer can be appropriately selected depending on the material of the base layer 13, the type of the elastic layer 14, and the form of the crosslinking reaction. In particular, when the elastic layer 14 contains a large amount of unsaturated aliphatic groups, a primer containing a hydrosilyl group is preferably used in order to impart adhesiveness by reacting with the unsaturated aliphatic group. When the elastic layer 14 contains a large amount of hydrosilyl groups, a primer containing an unsaturated aliphatic group is preferably used. Other primers include those containing an alkoxy group. Commercially available products can be used as the primer. Further, the primer treatment includes a step of applying the primer to the outer surface of the base layer 13 (adhesive surface with the elastic layer 14) and drying or firing the primer.

(2) Elastic layer The elastic layer 14 preferably contains a silicone rubber having excellent heat resistance. Further, as a raw material for the silicone rubber, an addition hardening type liquid silicone rubber is preferably used.
The thickness of the elastic layer 14 can be appropriately designed in consideration of the surface hardness of the fixing member and the width of the fixing nip portion to be formed. When the fixing member is the fixing belt 11, the thickness of the elastic layer 14 is preferably 100 μm or more and 500 μm or less, and more preferably 200 μm or more and 400 μm or less.
When the fixing member is the fixing roller 12, the thickness of the elastic layer 14 is preferably 0.1 mm (100 μm) or more and 3.0 mm or less, and more preferably 0.3 mm (300 μm) or more and 2.0 mm or less. preferable.
By setting the thickness of the elastic layer 14 within this range, a sufficient width of the fixing nip portion can be secured when the fixing member is incorporated into the fixing device.
In addition, since the elastic layer contains silicone rubber having poor chemical affinity with fluorine oil, the fluorine oil contained in the surface layer is difficult to transfer to the elastic layer even after long-term use, and is supplied exclusively to the surface of the fixing member. Fluorine.
The elastic layer 14 may contain a filler. Fillers are added to control thermal conductivity, heat resistance and elastic modulus. Specifically, silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), silica (SiO ₂ ), boron nitride (BN), aluminum nitride (AlN), alumina (Al ₂ O ₃ ), iron oxide (Fe). ₂ O ₃ ), zinc oxide (ZnO), magnesium oxide (MgO), titanium oxide (TiO ₂ ), copper (Cu), aluminum (Al), silver (Ag), iron (Fe), nickel (Ni), carbon Examples thereof include black (C), carbon fiber (C), and carbon nanotube (C).
Further, a reaction control agent (inhibitor) called an inhibitor for controlling the reaction start time may be added to the material constituting the elastic layer 14. As the reaction control agent, known substances such as methyl vinyl tetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohol, and hydroperoxide are used.

(3) Surface layer The surface layer 15 contains a fluororesin and a fluorine oil having a perfluoropolyether (PFPE) structure. Then, the surface layer satisfies the above-mentioned requirement (i) and requirement (ii).
The fixing member satisfying the requirement (i) and the requirement (ii) can be achieved by, for example, a surface layer containing a larger amount of fluorine oil on the base layer side than on the outer surface side in the thickness direction of the surface layer.
For example, for a measurement sample including the entire thickness portion of the surface layer collected from the fixing member, the detection surface of the quartz crystal microbalance (QCM) sensor is relative to the second surface on the side facing the base layer. Is pressed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. At this time, assuming that the mass P21 (ng) of the deposit containing fluorine oil having a perfluoropolyether structure adhering to the unit area (1 cm ² ) of the detection surface, P21 and P11 have the relationship of the following formula (1). The fixing member showing the above can achieve the requirement (i) and the requirement (ii).

P21> P11 (1)

Since both fluororesin and fluorooil have small surface free energies, it may be difficult to interact with each other without phase separation. However, the present inventors phase-separate the fluororesin from the fluororesin in the surface layer by bringing the fluorooil into contact with the outer surface of the surface layer at a temperature near the melting point of the fluororesin in the surface layer. It was found that it can be contained without any need. Further, when fluorine oil was contained in the surface layer by such a method, the fluorine oil permeated to the vicinity of the interface with the elastic layer in the surface layer in the thickness direction of the surface layer, and was in the vicinity of the interface. The fluorine oil concentration was higher in the surface layer than in the first surface side of the surface layer.
The reason why the concentration of fluorine oil is higher on the side of the surface layer near the elastic layer is not clear, but it is presumed as follows. First, by bringing the fluorine oil into contact with the fluororesin near the melting point, the fluorine oil rapidly diffuses in the fluororesin and reaches the vicinity of the interface with the elastic layer. Next, in the process of cooling the surface layer from the vicinity of the melting point of the fluororesin to room temperature, molecular shrinkage of the fluororesin in the surface layer occurs, and fluorine oil is released from the first surface side to the first surface of the surface layer. .. As a result, it is considered that the concentration of fluorine oil in the surface layer is higher on the interface side with the elastic layer than on the first surface side of the elastic layer.
Then, by forming such a concentration gradient of fluorine oil in the surface layer, the surface layer functions as a reservoir of fluorine oil. Therefore, even if the fluorine oil on the first surface of the surface layer is consumed during heat fixing, the fluorine oil of the surface layer is continuously supplied to the first surface by the principle of substance diffusion, and even in long-term use. It is considered that the toner releasability of the outer surface of the fixing member is maintained.

The difference in the concentration of fluorine oil between the first surface side and the interface side with the elastic layer in the thickness direction of the surface layer can be easily confirmed by, for example, measuring by infrared spectroscopy.

Any method can be used for producing the fixing member according to this embodiment as long as the fluorooil containing the PFPE structure can be contact-impregnated at a temperature near the melting point of the fluororesin contained in the surface layer. The surface layer to be brought into contact with the fluorine oil may be a surface layer of a fixing member in which a base layer, an elastic layer, and a surface layer are laminated in advance, or a fluororesin tube for the surface layer is prepared and adhered to the elastic layer. A state in which the surface on the side is masked may be used. Further, as a contact method, for example, it can be produced by a dipping method.
Specifically, for example, when the surface layer contains PFA as the fluororesin, it can be obtained through the following steps a) to c).
Step a) A pre-fixing member in which a base layer, an elastic layer containing silicone rubber, and a resin layer containing PFA are laminated in this order is attached to a dipping device.
Step b) Immerse the pre-fixing member in a fluorine oil bath heated in advance near the melting point of PFA (300 ° C ± 50 ° C) and leave it for 5 minutes.
Step c) After removing the pre-fixing member from the fluorine oil bath, the PFPE adhering to the outer surface of the resin layer is removed and cooled to room temperature.
The temperature of the fluorine oil bath in step b) correlates with the amount of fluorine oil impregnated into the resin layer, and the higher the temperature, the greater the impregnation amount. In addition, the contact time may be several to several tens of minutes. The method for removing the excess amount of PFPE adhering to the surface is not particularly limited, and examples thereof include a method of cleaning with a fluorine solvent and a method of removing with air.
The method of supplying fluorine oil to the outer surface of the resin layer is not limited to the dipping method described above. For example, as a method of supplying fluorine oil to the outer surface of the resin layer, known coating methods such as spray coating, roll coating, and beam coating can be used.

<Fluororesin>
The fluororesin is not particularly limited, and specifically, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), etc. Crystals of polychlorotetrafluoroethylene (PCTFE), tetrafluoroethylene-ethylene copolymer (ETFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), etc. Examples thereof include a fluororesin and an amorphous fluororesin having a cyclic perfluoropolyether structure. In particular, PFA can be preferably used from the viewpoints of heat resistance, mechanical strength, and workability.
PFA is a copolymer of perfluoroalkyl vinyl ether (hereinafter referred to as "PAVE") and tetrafluoroethylene (hereinafter referred to as "TFE"), and PAVE is perfluoromethyl vinyl ether (CF ₂ = CF-). It is selected from O-CF ₃ ), perfluoroethyl vinyl ether (CF ₂ = CF-O-CF ₂ CF ₃ ) and perfluoropropyl vinyl ether (CF ₂ = CF-O-CF ₂ CF ₂ CF ₃ ).

As the PFA, a commercially available product can be used, and specific examples are given below.
-"451HP-J""959HP-Plus""350-J""950HP-Plus" (all product names, manufactured by Mitsui Chemours Fluoro Products);
-"P-66P", "P-66PT", "P-802UP" (trade name, manufactured by AGC Inc.);
-"AP-230", "AP-231SH", etc. (both product names, manufactured by Daikin Industries, Ltd.);
-"6502N" (trade name, manufactured by 3M Ltd.).
Regarding PFA, the impregnation amount of PFPE correlates with the PAVE content ratio in PFA, and the impregnation amount increases as the PAVE content ratio increases. It is considered that this is because the fluorine oil easily interacts with the amorphous part of PFA having high molecular mobility. The content ratio of PAVE in PFA is preferably 1 mol% or more and 5 mol% or less, and particularly preferably 3 mol% or more and 5 mol% or less in the molecular chain. The PAVE content ratio can be calculated by measuring ¹⁹ F NMR.
Among the above-mentioned commercially available PFAs, "451HP-J", "959HP-Plus", "950HP-Plus", "P-66P", "P-66PT", "AP-231SH", "6502N", "AW-" The PAVE content ratio of "5000 L" is shown in Table 1.

<Fluorine oil>
Fluorine oil has a perfluoropolyether structure, and specific examples thereof include perfluoropolyether (PFPE) having a structure represented by the following structural formula (1). Among such PFPEs, those that become oily at the melting point of the fluororesin are preferably used.

(In the structural formula (1), a, b, c, d, e, and f are independently 0 or positive integers, satisfying 1 ≦ a + b + c + d + e + f ≦ 600, and of a, b, c, and d. At least one is a positive integer.)
Further, the existence order of each repeating unit in the structural formula (1) is not limited to the order described in the structural formula (1). Further, each repeating unit may exist at a plurality of places in the PFPE represented by the structural formula (1). That is, the PFPE represented by the structural formula (1) may be a block copolymer or a random copolymer.
From the viewpoint of heat resistance, the molecular weight of PFPE is preferably 5,000 or more, particularly 7,000 or more, as a number average molecular weight. Further, from the viewpoint of easiness of interaction with the fluororesin at the time of contact, it is preferably 100,000 or less, particularly preferably 30,000 or less. The weight loss of PFPE having the above molecular weight is less than 1% even when heated in air at 350 ° C. for 30 minutes, and thermal decomposition is extremely small even at a temperature near the melting point of the fluororesin.
The content of PFPE in the surface layer is preferably 1.0% by mass or more and 25% by mass or less with respect to the total amount of the fluororesin and PFPE. If it is less than 1% by mass, the releasability of the surface layer cannot be improved, and if it is more than 25% by mass, excess PFPE is likely to be supplied to the nip portion, and toner offset is likely to occur.

Specific examples of PFPE having a structure included in the structure represented by the structural formula (1) are given below. As an example, those having at least one chemical structure selected from the group consisting of the structural formulas (2) to (4) can be mentioned.
PFPE having the structure represented by the structural formula (2) (for example, "Demnum-S200" and "Demnum-S100" (both trade names; manufactured by Daikin Industries, Ltd., referred to as "Demnum type")):

(In structural formula (2), n represents an integer of 1 or more.)
PFPE having the structure represented by the structural formula (3) (for example, "Krytox GPL107", "Krytox GPL106", "Krytox 143AD", "Krytox VPF16256", "Krytox XHT-500", "Krytox XHT-750" , "Krytox XHT-1000" (both product names; manufactured by The Chemours Company, referred to as "Krytox type"):

(In structural formula (3), n represents an integer of 1 or more.)
PFA represented by the structural formula (4) (for example, "Fomblin M60" and "Fomblin M30" (both are trade names, manufactured by Solvay S., referred to as "Fomblin type")):

(M and n in the structural formula (4) independently represent an integer of 1 or more.)
The impregnation amount of perfluoropolyether correlates with the solubility parameter. Specifically, it can be controlled by the SP value difference (ΔHSP value) between the fluororesin and the perfluoropolyether, which is calculated from the Hansen solubility parameter (HSP value). When the ΔHSP value between the two components is small, both are easily dissolved, that is, they are more miscible and the impregnation amount is increased.
The ΔHSP value can be calculated using the 3rd Edition 3.1.14 of the calculation software “HSPiP” with a database developed and sold by the Hansen Group. When the present inventors calculated the ΔHSP values of PFA and PFPE, they were Krytox type = 2.8, Demnum type = 3.6, and Fomblin type = 5.4, and the affinity with PFA differs depending on the chemical structure of PFPE. It turned out. That is, when the PFPE of each chemical structure is brought into contact with the PFA under the same conditions, the Krytox type is most compatible with the PFA.
The thickness of the surface layer 15 is 3.0 μm or more, more preferably 5.0 μm or more, and particularly preferably 10 μm or more, from the viewpoint of suppressing surface wear during use of the fixing member. Further, from the viewpoint of suppressing a decrease in thermal conductivity in the thickness direction of the fixing member, 50 μm or less, particularly 40 μm or less is preferable.

2. 2. Heat fixing device The heat fixing device according to one aspect of the present invention includes a rotating body for heating, a rotating body for heating, and a rotating body for pressurization arranged so as to form a fixing nip portion. .. Examples of the combination of the rotating body for heating and the rotating body for pressurization include, for example, an elastic pressurizing roller formed by facing the heating roller and the heating roller, and abutting the heating film and the heating film. An elastic pressure roller can be mentioned. As another example of the combination of the rotating body for heating and the rotating body for pressurization, an elastic pressurizing roller arranged in contact with the heating belt and the heating belt, and an elastic pressure roller arranged in contact with the heating belt and the heating belt. An elastic pressure belt and the like can be mentioned.

(1) Fixing device using a fixing belt FIG. 4 is a cross-sectional view of a heat fixing device including a fixing belt 11 for heating and an elastic pressure roller 19 in a direction orthogonal to the longitudinal direction.
The fixing belt 11 is a fixing belt according to one aspect of the present invention. The fixing belt 11 is loosely fitted to the belt guide member 16. The pressurizing rigid stay 18 is inserted inside the belt guide member 16. The belt guide member 16 is made of, for example, a resin having heat resistance and heat insulating properties.
A ceramic heater 17 as a heat source is provided at a position where the belt guide member 16 and the inner surface of the fixing belt 11 come into contact with each other. The ceramic heater 17 is fitted and fixed in a groove provided along the longitudinal direction of the belt guide member 16. The ceramic heater 17 is energized by means (not shown) to generate heat.
The elastic pressure roller 19 is provided with, for example, an elastic layer 19b containing a cured silicone rubber on the peripheral surface of a stainless steel core metal 19a. Further, a surface layer 19c containing a fluororesin is provided on the peripheral surface of the elastic layer 19b. The thickness of the surface layer 19c is, for example, 50 μm.
By reducing the pressure springs (not shown) between both ends of the pressurizing rigid stay 18 and the spring receiving members (not shown) on the device chassis side, a pushing force is applied to the pressurizing rigid stay 18. ing. As a result, the lower surface of the ceramic heater 17 arranged on the lower surface of the belt guide member 16 and the upper surface of the elastic pressure roller 19 are pressed against each other with the fixing belt 11 sandwiched between them to form a predetermined fixing nip portion N. That is, the lower surface of the ceramic heater 17 is arranged in contact with the inner peripheral surface of the fixing belt 11.
The recording medium P, which is a heating element and whose image is formed by the unfixed toner G, is sandwiched and conveyed to the fixing nip portion N at a transfer speed V. As a result, the toner image is heated and pressurized. As a result, the toner image is melted and mixed in color, and then cooled to fix the toner image on the recording medium P.

(2) Heat Fixing Device Using Fixing Rollers FIG. 5 shows a fixing roller 12 for heating, an elastic pressurizing roller 19 arranged to face the fixing roller 12, and a heater 20 as a heating means for the fixing roller 12. It is sectional drawing in the direction orthogonal to the longitudinal direction of the heat fixing apparatus provided with.
The fixing roller 12 is a fixing roller according to one aspect of the present invention. In the fixing roller 12, an elastic layer 14 is formed on the outer peripheral surface of a hollow core metal as a base layer 13, and a surface layer 15 is further formed on the outer side thereof.
The fixing roller 12 and the elastic pressure roller 19 are rotatably pressed against each other by a pressure means (not shown) to form a fixing nip portion N.
Inside the fixing roller 12 and the elastic pressurizing roller 19, a heater 20 as a heat source is installed to supply heat necessary for melting the unfixed toner G. A halogen heater is generally used as the heater 20. A plurality of halogen heaters may be installed inside according to the size of the recorded recording medium P to be conveyed.
A rotational force is applied to the fixing roller 12 and the elastic pressure roller 19 through the ends of the base layer (core metal) 13 and the core metal 19a by means (not shown), and the moving speed of the surface of the fixing roller 12 is the transport speed V of the recording medium P. The rotation is controlled so that the velocity is almost constant. At this time, the rotational force may be applied to either the fixing roller 12 or the elastic pressure roller 19 having elasticity, and the other may be rotated by the driven motion, or the rotational force may be applied to both. ..
A recording medium P, which is a heating element on which an image is formed by the unfixed toner G, is sandwiched and conveyed to the fixing nip portion N of the fixing device thus formed. As a result, the toner image is heated and pressurized. As a result, the toner image is melted and mixed in color, and then cooled to fix the toner image on the recording medium P.

3. 3. Image forming apparatus Examples of the image forming apparatus include a multifunction device using an electrophotographic method, a copy, a fax machine, and a printer. Here, a color laser printer will be used as an example to outline the overall configuration of the image forming apparatus.
FIG. 6 is a schematic cross-sectional view of the laser printer 40 according to the uniform state of the present invention. The laser printer 40 shown in FIG. 6 is an electrophotographic photosensitive member drum 39 (hereinafter, “photoreceptor”) that rotates at a constant speed for each of the colors of yellow (Y), magenta (M), cyan (C), and black (K). It has an image forming part having a drum 39 ”). In addition, it has an intermediate transfer body 38 that holds a color image developed and multiplex-transferred by the image forming unit and further transfers the color image to the recording medium P fed from the feeding unit.
The photoconductor drum 39 (39Y, 39M, 39C, 39K) is rotationally driven counterclockwise as shown in FIG. 6 by a driving means (not shown).
Around the photoconductor drum 39, a charging device 21 (21Y, 21M, 21C, 21K) that uniformly charges the surface of the photoconductor drum 39 in order according to the rotation direction, and a laser beam based on image information are irradiated. , Scanner unit 22 (22Y, 22M, 22C, 22K) that forms an electrostatic latent image on the photoconductor drum 39, and development unit 23 (23Y, 23M) that adheres toner to the electrostatic latent image and develops it as a toner image. 23C, 23K), the primary transfer roller 24 (24Y, 24M, 24C, 24K) that transfers the toner image on the photoconductor drum 39 to the intermediate transfer body 38 by the primary transfer unit T1, and remains on the surface of the photoconductor drum 39 after transfer. A cleaning unit 25 (25Y, 25M, 25C, 25K) having a cleaning blade for removing the transfer residual toner is arranged.

In image formation, the belt-shaped intermediate transfer body 38 stretched on the rollers 26, 27, and 28 rotates, and each color toner image formed on each photoconductor drum 39 is superimposed on the intermediate transfer body 38 to be primary. A color image is formed by being transferred.
The recording medium P is conveyed to the secondary transfer unit T2 by the transfer means so as to be synchronized with the primary transfer to the intermediate transfer body 38. The transport means includes a feed cassette 29 containing a plurality of recording media P, a feed roller 30, a separation pad 31, and a resist roller pair 32. At the time of image formation, the feeding roller 30 is driven and rotated according to the image forming operation, the recording media P in the feeding cassette 29 are separated one by one, and the resist roller pair 32 synchronizes with the image forming operation and is secondary. It is conveyed to the transfer unit T2.
A movable secondary transfer roller 33 is arranged in the secondary transfer unit T2. The secondary transfer roller 33 can move substantially in the vertical direction. Then, at the time of image transfer, the secondary transfer roller 33 is pressed against the intermediate transfer body 38 with a predetermined pressure via the recording medium P. At the same time, a bias is applied to the secondary transfer roller 33, and the toner image on the intermediate transfer body 38 is transferred to the recording medium P.
Since the intermediate transfer body 38 and the secondary transfer roller 33 are each driven, the recording medium P sandwiched between them is conveyed in the direction of the left arrow shown in FIG. 6 at a predetermined transfer speed V, and is further conveyed. It is conveyed to the fixing portion 35, which is the next step, by the belt 34. Heat and pressure are applied to the fixing unit 35 to fix the transferred toner image on the recording medium P. The recording medium P is discharged onto the discharge tray 37 on the upper surface of the device by the discharge roller pair 36.
Then, by applying the fixing device of the present invention illustrated in FIGS. 4 and 5 to the fixing portion 35 and the secondary transfer roller 33 of the electrophotographic image forming device illustrated in FIG. 6, the uniformity of the image is excellent. It is possible to obtain an image forming apparatus capable of providing a high-quality image.

Hereinafter, the present invention will be specifically described with reference to Examples. The present invention is not limited to the following examples.

In this example, a fixing member was produced using the following fluororesin and fluorine oil.
(Fluororesin)
PFA-1: "959HP-Plus" (trade name, manufactured by Mitsui Chemours Fluoro Products)
PFA-2: "451HP-J" (trade name, manufactured by Mitsui Chemours Fluoro Products)
PFA-3: "950HP-Plus" (trade name, manufactured by Mitsui Chemours Fluoro Products)
PFA-4: "P66P" (trade name, manufactured by AGC Inc.)
PFA-5: "AW-5000L" (trade name, manufactured by Daikin Industries, Ltd.)
(Fluorine oil)
PFPE-1: "Krytox GPL107" (trade name, manufactured by The Chemours Company)
PFPE-2: "Krytox GPL106" (trade name, manufactured by The Chemours Company)
PFPE-3: "Demnum S200" (trade name, manufactured by Daikin Industries, Ltd.)
PFPE-4: "Krytox 143AD" (trade name, manufactured by The Chemours Company)
PFPE-5: "Krytox VPF16256" (trade name, manufactured by The Chemours Company)
PFPE-6: "Krytox XHT-1000" (trade name, manufactured by The Chemours Company)
PFPE-7: "Fomblin M60" (trade name, manufactured by Solvay)

(Example 1)
(Making a preliminary fixing belt)
As a base layer, a base material having an inner diameter of 30 mm, a width of 400 mm, and a thickness of 40 μm and having an endless belt shape made of nickel electroformed was prepared. The outer peripheral surface of this base material was subjected to primer treatment.
As a raw material for forming the elastic layer, an addition-curable liquid silicone rubber (trade name: SE1886, manufactured by Toray Dow Corning Co., Ltd.) containing no filler was prepared. With respect to 61 parts by volume of this liquid silicone rubber, 38 parts by volume of spherical alumina (trade name: Arnabeads CB-A30S, manufactured by Showa Denko) was used as a spherical filler, and vapor phase carbon fiber (trade name: VGCF) was used as a deformed filler. -S, manufactured by Showa Denko Co., Ltd., aspect ratio = 100, average fiber length = 10 μm) was added in an amount of 1 volume. In this way, an addition-curable silicone rubber composition for forming an elastic layer was prepared. These are applied onto the outer peripheral surface of the base material by the ring coating method and then heated at a temperature of 200 ° C. for 4 hours to crosslink the layers of the addition-curable silicone rubber composition to form an elastic layer having a thickness of 300 μm. Formed.
The base material on which the elastic layer is formed is rotated at a moving speed of 20 mm / sec in the circumferential direction, and is placed on the surface of the elastic layer by using an ultraviolet lamp arranged at a position where the distance from the surface of the elastic layer is 10 mm. Ultraviolet rays were irradiated in the air atmosphere. As the ultraviolet lamp, a low-pressure mercury ultraviolet lamp (trade name: GLQ500US / 11, manufactured by Toshiba Litec) was used, and irradiation was performed so that the integrated light amount of the wavelength of 185 nm on the irradiation surface was 800 mJ / cm ² .
Next, on the surface of the elastic layer, an addition hardening type silicone rubber adhesive (trade name: SE1819CV, "A solution" and "B solution" manufactured by Toray Dow Corning Co., Ltd. are mixed in equal amounts) to a thickness of about 20 μm. It was applied almost uniformly so as to be.
Next, a fluororesin tube (PFA-1, 20 μm thick, melting point 296 ° C.) whose inner surface is hydrophilically treated is covered, and the belt surface is uniformly handled from above the fluororesin tube to remove excess adhesive as an elastic layer. And the fluororesin tube.
Then, an elastic layer and a base layer coated with a surface layer are placed in an electric furnace set at a temperature of 200 ° C. and heated for 1 hour to cure the adhesive and bond the fluororesin tube onto the elastic layer. Both ends were cut to obtain a pre-fixing belt having a width of 343 mm.

(Contact impregnation of fluorine oil)
Perfluoropolyether (PFPE-1) was placed in a graduated cylinder made of borosilicate glass. A heating wire covered with a heat insulating material was wound around the entire graduated cylinder and heated so that the PFPE temperature became 285 ° C. The prepared pre-fixing belt was attached to a dipping device, and the entire fixing belt was immersed in heated PFPE. After 5 minutes, the pre-fixing belt was removed. Then, the pre-fixing belt was immersed in a graduated cylinder containing a separately prepared fluorine-based solvent (trade name: Novec7300, manufactured by 3M Ltd.) to remove excess PFPE adhering to the surface of the fixing belt. The fluorine-based solvent was dried to obtain the fixing belt No. 1 according to this embodiment. 1 was produced. Fixing belt No. For No. 1, two sets were prepared for use in the evaluation described later.
In addition, the fixing belt No. A photograph of the first surface of No. 1 observed by SEM is shown in FIG. The appearance of agglomeration of PFPE could not be observed, suggesting that PFA and PFPE are compatible with each other.

<Evaluation>
Three sets of measurement samples used for evaluations 1 to 3 were prepared as follows.
(Preparation of measurement sample)
Fixing belt No. A laminated body (diameter 10 mm) of the elastic layer and the surface layer was cut out from 1. Next, the elastic layer is removed from the laminate by immersing the laminate in a silicone resin dissolving agent ((trade name: e-solve 21RS, manufactured by Kaneko Kagaku Co., Ltd.) to dissolve the silicone rubber in the elastic layer. , A measurement sample was prepared containing the entire thickness portion of the surface layer.
(Evaluation 1: Measurement of fluorine oil adhesion amounts P11, P12 and P21)
The first surface on the side opposite to the side facing the base layer of the measurement sample was cleaned. That is, a non-woven fabric impregnated with ethanol was placed on the first surface, and a load of 20 kPa was applied on the non-woven fabric to reciprocate the position 10 times. Subsequently, a non-woven fabric was placed on the surface soaked with toluene, and a load of 20 kPa was applied on the non-woven fabric to reciprocate the position 10 times.
Next, the crystal oscillator was placed on the stage portion of the tack tester (trade name: TAC-1000, manufactured by Resca Co., Ltd.), while the probe portion of the tack tester was provided with a measurement sample, and the first surface was the surface. It was attached so as to face the crystal oscillator. The probe was then brought close to the stage and pressed against the crystal unit against the first surface of the measurement sample. The pressing conditions are as follows.
・ Pressure: 0.4 MPa,
・ Pressing time: 50 msec,
・ Constant push mode,
-Pressing and pulling speed: 1.0 mm / sec,
-Probe set temperature: 180 ° C.
As the crystal oscillator, "6A202PN" (trade name, manufactured by Piezo Parts Co., Ltd.) having a fundamental frequency of around 6 MHz was used. The frequency characteristics before and after adhesion were measured by using a QCM-D intermolecular interaction analysis system (Biolin Scientific AB) to measure changes in the series resonance frequency Fs before and after pressing and the frequency Fw indicating the loss of vibration energy. Then, the amount of fluorine oil adhered P11 per unit area (1 cm ² ) of the crystal unit was calculated from the above formula (a).
Immediately after the completion of the pressing process, the measurement sample was removed from the probe, and the first surface was cleaned in the same manner as described above. Then, the measurement sample was placed in an environment at a temperature of 180 ° C. for 120 seconds, and then the measurement sample was attached to the probe again and pressed against the crystal oscillator under the same pressing conditions as described above. Then, the changes in the series resonance frequency Fs and the frequency Fw representing the loss of vibration energy were measured, and the amount of fluorine oil adhered P12 per unit area (1 cm ² ) of the crystal oscillator was calculated from the above equation (a).

(Evaluation 2; Fluorine oil content in the surface layer)
The first surface and the second surface of another measurement sample were cleaned. Next, this measurement sample was measured using a thermogravimetric analyzer (TGA) under the following conditions, and the content ratio (wt%) of fluorine oil to the surface layer was calculated.
Equipment: TGA851 (manufactured by METTLER TORDO);
Atmosphere: in the air;
Temperature: 425 ° C.
In the measurement time-weight loss rate profile obtained by the above thermogravimetric analysis, a linear least squares approximation formula is obtained from the region where the slope is constant and only PFA is reduced (specifically, the measurement time is 3000 seconds or later). I asked. The intercept of the linear least squares approximation formula was taken as the PFA amount (wt%), and was calculated as the PFPE content (wt%) = 100-PFA amount.

(Evaluation 3; Relative ratio of PFPE amount on the outermost surface side and elastic layer side in the thickness direction of the surface layer)
The first surface and the second surface of yet another measurement sample were cleaned. Next, this measurement sample was measured by the ATR method from the first surface side and the second surface side using an infrared spectroscope (trade name: Frontier MIRNIR, manufactured by PerkinElmer), and the relative ratio of the amount of PFPE. (Hereinafter referred to as "PFPE relative amount ratio") was calculated.
Specifically, from each of the profile obtained by the infrared spectroscopic analysis, a peak appearing only PFPE (Krytox ^type: 986 cm -1, Demnum ^type: 1010 cm -1, Fomblin type: 1052cm ^-1) the height of the , The peak ratio was calculated by dividing by the height of the peak (1146 cm ^-1 ) appearing only in PFA. Next, the PFPE relative amount ratio was calculated by dividing the peak ratio calculated from the measurement result on the second expression side by the peak ratio calculated from the measurement result on the first surface side.

(Evaluation 4: Evaluation of the presence or absence of toner offset)
Fixing belt No. 1 was mounted on an electrophotographic image forming apparatus (trade name: imageRUNNER-ADVANCE C5051; manufactured by Canon Inc.) in which the angle of the paper separation claw was adjusted.
Then, an image forming process of forming a 10 cm × 10 cm cyan solid image on A4 size paper (manufactured by International Paper Co., Ltd., basis weight 75 g / m ² ) was carried out. The fixing temperature was 180 ° C., and the paper transport speed was 300 mm / sec.
Then, when the number of solid cyan images formed reached 1, 100, and 100,000, A4 size plain paper thin paper (trade name: CS-520, basis weight 52 g / m ² , Canon). A solid image of 10 cm × 10 cm in cyan color was formed by passing one sheet of paper. The solid image formed on this plain paper thin paper was visually observed and observed with a microscope, and evaluated according to the following criteria.
(Evaluation criteria)
Rank A: There is neither toner offset nor missing toner.
Rank B: Toner offset and missing toner are confirmed in small amounts Rank C: Both toner offset and missing toner are confirmed.
Rank D: Plain paper thin paper stuck to the fixing belt.

(Evaluation 5: Measurement of surface free energy)
In evaluation 4, the fixing belt No. immediately before forming a solid image on plain paper and thin paper. The surface free energy of the outer surface of No. 1 was calculated by the "Kitasaki-field method" described in Non-Patent Document 1. Specifically, the fixing belt No. The contact angles of water, n-hexadecane, and diiodomethane were measured on the outer surface of No. 1 (measurement environment: temperature 23 ° C., relative humidity 55%).
Then, using the measurement results of each contact angle, according to the description of "2. Extension of Forks formula" to "3. Surface tension of polymer solid and its components" on page 131 of Non-Patent Document 1, "Expanded Forces" The surface free energy was calculated from the formula of.
A contact angle meter (trade name: DM-501, manufactured by Kyowa Interface Science Co., Ltd.) was used to measure the contact angle, and analysis software (trade name: FAMAS, manufactured by Kyowa Interface Science Co., Ltd.) was used for surface free energy analysis. ..

(Examples 2 to 18)
The fixing belt No. 2 according to each example was obtained in the same manner as in Example 1 except that the fluororesin type and fluorine oil type used for the surface layer and the fluorine oil temperature at the time of contact were changed as shown in Table 2. 2 to 18 were prepared.

(Example 19)
In Example 1, the fixing belt No. 1 was the same as in Example 1 except that the contact time between the fixing member and the fluorine oil was set to 1 minute. 19 was prepared and subjected to evaluations 1 to 5.

(Example 20)
In Example 1, a solution obtained by diluting PFPE with a fluorine-based solvent (trade name: Novec7300, manufactured by 3M Ltd.) was spray-coated on the surface of the fixing member, and then placed in a drying oven and heated at 285 ° C. for 5 minutes. In the same manner as in Example 1, the fixing belt No. 20 was made.

(Comparative Example 1)
A preliminary fixing belt was produced by the method described in Example 1, and the fixing belt No. 2 according to this comparative example was used. It was designated as C-1.

(Comparative Example 2)
Fixing belt No. Sodium naphthalene (trade name: Tetra Etch, manufactured by Junko Co., Ltd.) was applied to the outer surface of C-1 to chemically hydrophilize the outer surface.
Next, PFPE (trade name: Optool DSX, manufactured by Daikin Industries, Ltd.) having a molecular terminal modified with alkoxysilane was dissolved in a fluorine-based solvent (trade name: Novec7300, manufactured by 3M Ltd.). Then, after applying the solution to the hydrophilic outer surface, it was calcined for 1 hour in a drying oven heated to 120 ° C. to chemically fix PFPE. Then, the outer surface on which the PFPE was chemically fixed was washed with the above-mentioned fluorine-based solvent, and the fixing belt No. 1 according to this comparative example was washed. C-2 was prepared.

(Comparative Example 3)
The fixing belt No. 1 was obtained in the same manner as in Example 1 except that the temperature of the fluorine oil in contact with the outer surface of the pre-fixing belt was 210 ° C. C-3 was prepared.
(Comparative Example 4)
The base layer and the elastic layer were prepared by the method described in Example 1. After treating the surface of the elastic layer with excimer UV, a primer (trade name: EK-1909S21L, manufactured by Daikin Industries, Ltd.) was uniformly spray-coated to a thickness of 2 μm and dried.
Then two spray guns were prepared. One spray gun was filled with a water-based dispersion paint of PFA particles (trade name: AW-5000L, manufactured by Daikin Industries, Ltd., melting point 300 ° C.). The other spray gun was filled with a solution of PFPE-1 dissolved in a fluorine-based solvent (trade name: Novec7300, manufactured by 3M Ltd.). Then, using these spray guns, the water-based dispersion coating material of PFA and PFPE were applied to the surface of the elastic layer to form a coating film having a thickness of 20 μm containing PFA particles and PFPE. At this time, the coating amount of the spray gun was adjusted so that the content of PFPE-1 in the coating film was 2.0 wt%.
Next, the coating film was heated at a temperature of 350 ° C. for 15 minutes to melt the PFA particles in the coating film to form a surface layer to obtain a fixing member according to Comparative Example 5. The content of fluorine oil in the surface layer and the relative amount ratios of P11, P12, P21 and PFPE in the surface layer were calculated in the same manner as in Example 1 and used for Evaluation 1 and Evaluation 2. Further, FIG. 2 shows a photograph of the outermost surface side of the surface layer observed by SEM. It can be observed that PFPE is aggregated, and it can be seen that PFA and PFPE are not compatible with each other.
Fixing belt No. 2 to 20, and fixing belt No. C-1 to C-4 were subjected to evaluations 1 to 5. The results are shown in Tables 2 and 3.

Table 3 shows the results of subjecting the fixing members produced in Examples 1 to 20 and Comparative Examples 1 to 4 to Evaluation 1 and Evaluation 2.

From Table 3, it was found that the fixing member according to this embodiment can maintain excellent toner releasability even after long-term use, and as a result, a high-quality electrophotographic image can be formed.

11 Fixing belt 12 Fixing roller 13 Base layer 14 Elastic layer 15 Surface layer

Claims (14)

A fixing member for electrophotographic having a base layer, an elastic layer, and a surface layer on the elastic layer in this order in the thickness direction.
The elastic layer contains silicone rubber and contains
The surface layer consists of a single layer
The surface layer contains a fluororesin and a fluorine oil having a perfluoropolyether structure, and the fixing member satisfies the requirement (i) and the requirement (ii).
(I) After cleaning a predetermined position on the first surface of the measurement sample including the entire thickness portion of the surface layer collected from the fixing member on the side opposite to the side facing the base layer, the measurement sample is cleaned. The unit area of the detection surface when the detection surface of the quartz crystal microbalance (QCM) sensor is pressed against the position at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. The mass P11 of the deposit containing the fluorine oil having a perfluoropolyether structure adhering to (1 cm ² ) is 1.0 × 10 ² ng or more and 1.0 × 10 ⁴ ng or less;
(Ii) For the measurement sample subjected to the treatment specified in the requirement (i), after cleaning the position, the measurement sample was placed in an environment at a temperature of 180 ° C. for 120 seconds, and then the quartz crystal microbalance was placed in the position. QCM) Perfluoropolyether structure that adheres to the unit area (1 cm ² ) of the detection surface when the detection surface of the sensor is pressed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. The mass P12 of the deposit containing the fluorine oil having the above is 0.5 × P11 or more and 1.2 × P11 or less. A fixing member for electrophotographic having a base layer, an elastic layer, and a surface layer on the elastic layer in this order in the thickness direction.
The elastic layer contains silicone rubber and contains
The surface layer consists of a single layer
The surface layer contains a fluororesin and a fluorooil having a perfluoropolyether structure.
Quartz crystal microbalance (QCM) sensor for a measurement sample including the entire thickness portion of the surface layer collected from the fixing member with respect to the first surface on the side opposite to the side facing the base layer. Fluorine oil having a perfluoropolyether structure that adheres to the unit area (1 cm ² ) of the detection surface when the detection surface is pressed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. The mass of the kimono is P11 (ng).
With respect to the second surface of the measurement sample facing the base layer, the detection surface of the quartz crystal microbalance (QCM) sensor was placed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. When the mass of the deposit containing fluorine oil having a perfluoropolyether structure, which adheres to the unit area (1 cm ² ) of the detection surface when pressed, is P21 (ng), P21> P11. Fixing member. The fixing member according to claim 1 or 2, wherein the content of the fluorine oil in the surface layer is 1.0% by mass or more and 25% by mass or less of the surface layer. The fixing member according to any one of claims 1 to 3, wherein P11 is 1.0 × 10 ² ng or more and 5.0 × 10 ³ ng or less. The fixing member according to any one of claims 1 to 4, wherein the fluororesin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA). The fixing member according to any one of claims 1 to 5, wherein the thickness of the surface layer is 5.0 μm or more and 50 μm or less. The fixing member according to any one of claims 1 to 6, wherein the fluorine oil is a perfluoropolyether. The fixing member according to any one of claims 1 to 7, wherein the perfluoropolyether has a chemical structure represented by the structural formula (1).
(In the structural formula (1), a, b, c, d, e, and f are independently 0 or positive integers, satisfying 1 ≦ a + b + c + d + e + f ≦ 600, and of a, b, c, and d. At least one represents a positive integer.) The fixation according to any one of claims 1 to 8, wherein the perfluoropolyether has at least one chemical structure selected from the group consisting of structural formulas (2) to (4). Element.
(In structural formulas (2) to (4), m and n each independently represent an integer of 1 or more.) The perfluoropolyether has the chemical structure of the formula (3), the P11 is 1.0 × 10 ² ng or more and 5.0 × 10 ³ ng or less, and the perfluoropolyether in the surface layer. The fixing member according to claim 9, wherein the content of the fixing member is 1.0% by mass or more and 25% by mass or less of the surface layer. The fixing member according to any one of claims 1 to 10, wherein the fixing member is a fixing belt having an endless belt shape. A fixing device comprising the fixing member according to any one of claims 1 to 10 and a heating means for the fixing member. The fixing device according to claim 12, wherein the fixing member is a fixing belt having an endless belt shape, and the heating means is a heater arranged in contact with the inner peripheral surface of the fixing belt. An electrophotographic image forming apparatus comprising the fixing apparatus according to claim 12 or 13.