JP6909040B2 - Fixing member for electrophotographic, fixing device and electrophotographic image forming device - Google Patents

Description

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

In the fixing step in the electrophotographic image forming apparatus, when unfixed toner on a recording medium such as paper is melted and fixed, the melted toner adheres to the surface of the fixing member, which is called "offset". The phenomenon may occur.
In order to suppress such a phenomenon, Patent Document 1 discloses a fixing device having a fixing roller, a pressure roller, an oil application mechanism on the surface of the fixing roller, and a cleaning means for contacting the pressure roller. is doing.

Japanese Unexamined Patent Publication No. 10-10904

The oil coating mechanism on the surface of the fixing roller according to Patent Document 1 can be an obstacle to miniaturization of the electrophotographic image forming apparatus. Therefore, the present inventors have come to recognize that it is necessary to develop a fixing member capable of maintaining high toner releasability for a long period of time regardless of a device such as an oil coating mechanism.
Therefore, one aspect of the present invention is to provide a fixing member for electrophotographic, which is excellent in toner releasability and can form a high-quality fixing image for a long period of time.
In addition, another aspect of the present invention is aimed at providing a fixing device and an electrophotographic image forming device capable of stably forming a high-quality electrophotographic image.

According to one aspect of the present invention, it is an electrophotographic fixing member having a base layer, an elastic layer, and a surface layer.
The elastic layer contains fluorooil having a perfluoropolyether structure and fluororubber.
The surface layer is composed of an amorphous fluororesin film having a cyclic perfluoropolyether structure.
The membrane has a porous structure with a plurality of pores, and the plurality of pores retain a fluorine oil having a perfluoropolyether structure.
As the fixing member, a fixing member for electrophotographic that satisfies the following condition (i) is provided:
From the condition (i)] of the surface layer surface, at least, to absorb the weight of the fluorine oil surface layer corresponds to the total mass of including fluorine oil was removed, subsequently, the surface of the surface layer in contrast, the detection surface of the quartz crystal microbalance (QCM) sensor at a pressure of 0.4 MPa, at a temperature 180 ° C., which adheres between 50 msec, the unit area of the detection plane (1 cm ²⁾ when pressed The mass of the deposit containing fluorine oil is 1.0 × 10 ² ng or more and ^{less than 5.0 × 10 3} ng.

According to another aspect of the present invention, a fixing device having the fixing member is provided.
According to still another aspect of the present invention, an image carrier, a charging device that charges the image carrier, and an exposure device that irradiates the charged image carrier with exposure light to form an electrostatic latent image. A developing device that develops an electrostatic latent image formed on the image carrier with toner to form a toner image, a transfer device that transfers the toner image formed on the image carrier to a recording medium, and the recording. Provided is an electrophotographic image forming apparatus having a fixing device for fixing a toner image transferred to a medium, the fixing device being the fixing device.

According to one aspect of the present invention, it is possible to obtain a fixing member for electrophotographic which is excellent in toner releasability and can form a high-quality fixing image for a long period of time.
Further, according to another aspect of the present invention, it is possible to obtain a fixing device and an electrophotographic image forming device capable of stably forming a high-quality electrophotographic image.

It is sectional drawing which shows an example of the fixing member which concerns on one Embodiment of this invention. It is sectional drawing which shows an example of the fixing device which concerns on one Embodiment of this invention. It is sectional drawing which shows an example of the electrophotographic image forming apparatus which concerns on one Embodiment of this invention. It is an SEM image of the surface of the fixing member which concerns on Example 1. FIG.

The present inventors have repeatedly studied to support the function of gradually supplying fluorine oil having excellent releasability to the surface of the fixing member on the fixing member itself which is in direct contact with the unfixed toner. As a result, it was found that by providing a fixing member having an elastic layer and a surface layer and each having the following functions, fluorine oil having excellent mold releasability is gradually supplied (released) to the surface of the fixing member. rice field.
That is, the elastic layer has a function as an oil storage layer by being configured so that the fluorine oil is appropriately retained in the layer. Further, the surface layer is provided on the outer surface of the elastic layer, and by providing a porous structure having a plurality of pores, the fluorine oil contained in the elastic layer is gradually transferred to the surface side of the fixing member. It has a function as a layer having oil permeability.
According to the fixing member provided with the elastic layer and the surface layer having these functions, the fluorine oil stored in the elastic layer migrates through the surface layer and is gradually released to the surface of the fixing member, so that the fluorine oil can be used for a long period of time. It was found that it can be supplied to the surface of the fixing member.

[Fixing member for electrograph]
Hereinafter, the fixing member for electrophotographic according to the embodiment of the present invention will be described in detail with reference to FIG.
FIG. 1 is a cross-sectional view of a fixing member 10 having a roller shape (hereinafter, also referred to as a “fixing roller”) according to one aspect of the present invention in a direction orthogonal to the longitudinal direction. The shape of the fixing member is not limited to the roller shape, but may be a belt shape.
The fixing roller 10 has a cylindrical base layer 11, an elastic layer 12, and a surface layer 13. The elastic layer 12 contains a fluorooil having a perfluoropolyether structure and a fluororubber. Further, the surface layer 13 contains a fluororesin and a fluorine oil having a perfluoropolyether structure, and has a porous structure having a plurality of pores.

Then, the fixing roller 10 satisfies the following condition (i):
[Condition (i)] Fluorine oil having a perfluoropolyether structure having a mass corresponding to at least the total mass of the fluorine oil contained in the surface layer 13 is absorbed and removed from the surface of the surface layer 13. Subsequently, when the detection surface of the quartz crystal microbalance (QCM) sensor is pressed against the surface of the surface layer at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec, the unit of the detection surface. The mass of the deposit containing fluorine oil having a perfluoropolyether structure adhering to the area (1 cm ^{2 ) is 1.0 × 10 2} ng or more and ^{less than 5.0 × 10 3} ng.
That is, the condition (i) is satisfied even when the amount corresponding to the fluorine oil having a perfluoropolyether structure contained in the surface layer 13 in the initial state is lost from the fixing roller 10. Fluorine oil having a perfluoropolyether structure stored in the elastic layer 12 is transferred to the surface layer 13 by fixing under general fixing conditions such as 4 MPa, a temperature of 180 ° C., and a pressing time of 50 msec. It has a technical meaning that the amount of fluorine oil having a perfluoropolyether structure adhering to the object to be fixed (fixed image) from the surface of the surface layer 13 is controlled within an appropriate range.

Here, the elastic layer 12 containing fluorine oil having a perfloolopolyether structure functions as a storage layer for fluorine oil. Further, since the surface layer 13 has a porous structure having a plurality of pores and functions as a layer having oil permeability, the fluorine oil in the elastic layer 12 passes through the porous structure. It shifts to the surface of the fixing member 10. The fluorine oil in the elastic layer 12 and the fluorine oil initially held in the porous structure migrate to the surface of the fixing member 10 and function as a release agent for toner. At this time, since the pore size of the porous structure is fine, the amount of oil transferred to the surface of the fixing member 10 can be controlled to be very small. Further, even after the fluorine oil retained in the porous structure at the initial stage disappears after long-term use, the fluorine oil is supplied from the elastic layer 12 by applying heat and pressure, so that the toner can be used for a long period of time. Releasability can be guaranteed. Further, since the amount of fluorine oil supplied to the surface of the fixing member 10 is very small, it is possible to suppress the deterioration of the quality of the fixing image caused by the excessive presence of the fluorine oil.

Hereinafter, each layer constituting the fixing member will be described in more detail.
(Base layer)
In the case of the roller-shaped fixing member, the material forming the cylindrical base layer is not particularly limited, and examples thereof include metals such as aluminum, stainless steel, brass, and copper, glass, and ceramics.
Further, in the case of a seamless belt-shaped fixing member, the material constituting the belt-shaped base layer is not particularly limited, and examples thereof include resins such as polyimide, polyamide and polyamideimide; and metals such as nickel and stainless steel.

(Fluorine oil)
The fluorine oil contained in the elastic layer and the surface layer has a perfluoropolyether structure. The fluorine oil having a perfluoropolyether structure (hereinafter, may be simply referred to as fluorine oil) is not particularly limited as long as it has a perfluoropolyether structure. For example, F (CF ₂ CF ₂ CF ₂ O) _m R _f , F (CF (CF ₃ ) CF ₂ O) _m R _f , R _f (OCF ₂ CF ₂ ) _m (OCF ₂ ) _n OR _f , R _f (OCF (CF ₃ ) CF ₂ ) _m (OCF ₂ ) _n OR _f , which has only a linear structure or a part of a branched structure, is appropriately selected. Here, R _f represents an arbitrary perfluoroalkyl group, respectively. m and n each independently represent an arbitrary integer of 1 to 200. Of these, those having heat resistance are particularly preferable. For example, the weight loss rate after heating at 250 ° C. for 1 hour in the air is preferably less than 10%, more preferably less than 5.0%, and particularly less than 1.0%. preferable.

(Surface layer)
The surface layer contains a fluororesin and a fluorooil having a perfluoropolyether structure, and has a porous structure having a plurality of pores. Fluorine oil is retained in the pores of the porous structure, and a part of it moves to the surface of the surface layer at the time of fixing and is lost from the surface layer by adhering to the object to be fixed (fixed image). On the other hand, at the time of fixing, a part of the fluorine oil stored in the elastic layer is transferred to the surface layer, so that new fluorine oil is supplied into the pores of the porous structure and held in the pores. Therefore, the fluorine oil held in the pores of the porous structure in the initial state (when not in use) is gradually lost with use, but new fluorine oil is replenished from the elastic layer. The state in which the fluorine oil is retained in the pores of the porous structure is maintained for a long period of time.

The fluororesin is not particularly limited, but is polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotetra. Crystalline fluororesins such as fluoroethylene (PCTFE), tetrafluoroethylene-ethylene copolymer (ETFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), etc. Also, an amorphous fluororesin having a cyclic perfluoropolyether structure can be mentioned.

Of these, an amorphous fluororesin (cyclic par) having a cyclic perfluoropolyether structure has a high chemical affinity with a fluorooil having a perfluoropolyether structure and is excellent in film formation from a solution state. Fluoropolyether resin) is preferable.

As a result of diligent studies by the present inventors, it has been found that when an amorphous fluororesin having a cyclic perfluoropolyether structure is formed, a porous body having a fine pore size is formed. It is considered that this is because phase separation between the resin component and the solvent is likely to occur in the process of volatilizing the solvent from the solution state, and as a result, pores are formed. Therefore, the pore size can also be controlled by changing the resin concentration at the time of film formation. As described above, since the pores of this porous structure are fine and suitable for controlling the surface transfer amount of fluorine oil to a very small amount, the present invention has been completed.

In addition, since the amorphous fluororesin having a cyclic perfluoropolyether structure has a high chemical affinity with fluorine oil, the fluorine oil does not easily disappear from the surface layer even if it is contacted or rubbed during the fixing nip. Durability is improved. Furthermore, since the amorphous fluororesin having a cyclic perfluoropolyether structure is formed from a solution state, it is easy to stack, and when it is applied, a part of it soaks into the lower layer and cures in that state, so that it has adhesiveness. Is improved.

（ΔＦ:周波数変化、Δｍ:質量変化量、Ｆ_０:基本周波数、ρ_Ｑ:水晶の密度、μ_Ｑ:水晶のせん断応力、Ａ:電極面積）
この測定方法は、水晶振動子マイクロバランス（Quartz Crystal Microbalance：ＱＣＭ）法とも称される。 The amount of fluorine oil having a perfluoropolyether structure on the surface of the surface layer can be measured using a crystal oscillator. The crystal unit has a sensitivity capable of measuring a mass on the order of ng to μg. The crystal oscillator has a structure in which crystal crystals are cut on an ultra-thin plate and metal thin films are attached to both sides. When an AC electric field is applied to the metal electrodes on both sides, a constant frequency (resonance) is caused by the inverse piezoelectric effect of the crystal. It has the property of vibrating at (frequency). When a small amount of substance is adsorbed on the metal thin film, the resonance frequency decreases in proportion to the mass of the substance, so that it can be used as a minute balance. It is known that the amount of change in frequency and the mass of the adhering substance on the electrode follow the following Sauebrey's 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.

As a result of diligent studies, the present inventors have found an extremely suitable amount of fluorine oil on the surface of the fixing member, and have come up with the present invention. That is, it was found that the desired effect can be obtained by setting the amount of fluorine oil calculated by the following method within a suitable range.
Specifically, first, the crystal oscillator is placed on the stage portion of the tack tester TAC-1000 (manufactured by Reska Co., Ltd.), and the fixing member attached to the probe portion of the tack tester is pressed against the oscillator from above. When pressing the fixing member, the pressure was pressed under the conditions of 0.4 MPa, pressing time 50 msec, constant pressing amount mode, pressing and pulling speed 1.0 mm / sec, and probe set temperature 180 ° C. At this time, the amount of fluorine oil having a perfluoropolyether structure adhering to the unit area (1 cm ^{2 ) of the crystal oscillator detection surface is 1.0 × 10 2} ng or more and 5.0 × 10 ³ ng. Is less than.

The above pressing conditions are similar to the conditions for the fixing nip, and when the amount of adhesion is within the above range, the fixing conditions are free from the harmful effects caused by fluorine oil even in long-term use in an actual machine. If the amount of adhesion is ^{less than 1.0 × 10 2} ng, the releasability is lowered, so that toner offset is likely to occur, and the resulting image deterioration is likely to occur. Further, when the amount of adhesion is 5.0 × 10 ³ ng or more, toner offset due to excess fluorine oil and uneven gloss due to transfer of excess fluorine oil to the image are likely to occur.

Here, the surface layer uses the fluorine oil contained in the elastic layer so that the deposits adhering to the detection surface contain the fluorine oil having a perfluoropolyether structure contained in the elastic layer. It is preferable that the surface layer is passed in the thickness direction. That is, it is preferable that the surface layer has oil permeability for allowing fluorine oil having a perfluoropolyether structure in the elastic layer to permeate.

Specific examples of the amorphous fluororesin having a cyclic perfluoropolyether structure include, but are not limited to, the structures represented by the following formulas (1) to (3).

In the formulas (1) to (3), n _{1 to} n ₃ and m _{1 to} m ₃ are arbitrary integers of 1 or more, and may be appropriately selected depending on the intended purpose, and are not particularly limited. For example, n ₁ is 100 or more and 2000 or less, m ₁ is 300 or more and 4500 or less, n ₂ is 100 or more and 2000 or less, m ₂ is 300 or more and 4500 or less, n ₃ is 100 or more and 1500 or less, and m ₃ is 100 or more and 1500 or less. be.

The average pore size of the porous structure is preferably 1 nm or more and 200 nm or less, and more preferably 10 nm or more and 100 nm or less. When the average pore diameter is 1 nm or more, the transferability of the fluorine oil to the surface of the fixing member is high, and the releasability is unlikely to decrease due to long-term use, which is preferable. Further, when the average pore diameter is 200 nm or less, the amount of fluorine oil on the surface of the fixing member does not become excessive, toner offset, image density unevenness, and gloss unevenness are suppressed, and toner particles are hard to enter into the pores to the fixing member. The generation of residual toner can be suppressed.

The thickness of the surface layer is preferably 10 nm or more and 20 μm or less. When the thickness of the surface layer is 10 nm or more, the disappearance of the surface layer due to durable wear is suppressed. The presence of the surface layer can prevent the elastic layer that supplies excess fluorine oil to the contact object from being exposed to the surface, and can also suppress uneven gloss and toner offset due to excess fluorine oil. When the thickness of the surface layer is 20 μm or less, the heat capacity does not become too large, and the heat from the heating source inside the fixing member can be sufficiently transferred to the toner.

The surface layer may contain a heat conductive filler such as an inorganic oxide, boron nitride, carbon black, or carbon fiber, if necessary, for the purpose of improving the heat conductivity and the like.

The surface layer preferably has a surface free energy of 10 mJ / m ² or more and 15 or less mJ / m ² , and more preferably 10 mJ / m ² or more and 15 or less mJ / m ² .

(Elastic layer)
The elastic layer contains a fluorooil having a perfluoropolyether structure and a fluororubber.
The fluororubber preferably has a high affinity with fluorooil and has heat resistance. Specifically, general fluororubbers such as binary and ternary vinylidene fluoride fluororubbers (FKM) and silicone-modified fluororubbers (also referred to as fluorosilicone rubbers) obtained by silicone-modifying these are preferably preferred. Used. Examples of binary and ternary vinylidene fluoride fluororubbers include Daiel (manufactured by Daikin Industries, Ltd.), Viton, and Callets (manufactured by DuPont). Examples of the silicone-modified fluororubber include SIFEL (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.
Further, it is preferably formed from a liquid addition type fluororubber in consideration of ease of molding and heat curability when forming an elastic layer. These fluororubbers may be formed from either a one-component type or a two-component type.

The elastic layer is a layer containing fluorine oil having a perfluoropolyether structure. The method of including the fluorooil in the elastic layer is not particularly limited, and the fluororubber may be added to the fluororubber in a liquid state and then the fluororubber may be cured, or the fluororubber after curing may be cured with the fluoropolymer. May be impregnated.

It is preferable that the fluorooil contained in the elastic layer has a controlled chemical affinity with the fluororubber constituting the elastic layer. The chemical affinity can be controlled by the difference in solubility parameter (SP value) between the two.

Here, the solubility parameter (SP value) in the present invention is a measure of the affinity of two or more substances, and is a parameter represented by the square root of the molecular aggregation energy. In the present invention, the SP value is derived using Hansen's method. Here, Hansen's method expresses the energy of one substance _{by three components, the dispersion energy term (δ D} ), the polarization energy term (δ _P ), and the hydrogen bond energy term (δ _H ), and is a vector in three-dimensional space. It is expressed as. If the difference in SP value between the two substances is small (the distance between the two substances is short), it means that the two substances are highly soluble, that is, they are easily mixed. On the other hand, when the difference in SP value between the two substances is large (the distance between the two substances is long), it means that the two substances have low solubility, that is, they are difficult to mix.

_{The parameters of δ D} , δ _P , and δ _H in the present invention and the parameters for each substituent used when calculating by the group contribution method are the 3rd Edition 3 of the calculation software "HSPiP" with a database developed and sold by the Hansen Group. Calculate using 1.14. At this time, the SP value of each component is calculated based on the following formula (b).
SP value = (δ _D ² + δ _P ² + δ _H ² ) ^0.5 (b)

Further, the difference (ΔSP) of the solubility parameter between the two types of components is defined by the distance in the above three-dimensional space, and the value is calculated by the following formula (c).
ΔSP = {4 (δ _{D1 −} δ _D2 ) ² + (δ _{P1 −} δ _P2 ) ² + (δ _{H1 −} δ _H2 ) ² } ^0.5 (c)

The absolute value ΔSP of the difference in solubility parameters between the fluorooil contained in the elastic layer and the fluororesin contained in the elastic layer is preferably 1 (MPa) ^0.5 or more and 13 (MPa) ^0.5 or less, and further. It is preferably 1 (MPa) ^0.5 or more and 7.5 (MPa) ^0.5 or less.

When ΔSP is 1 (MPa) ^0.5 or more, the interaction between the fluororesin and the fluorine oil does not become too large. Good releasability can be exhibited. Further, when ΔSP is 13 (MPa) ^0.5 or less, the interaction between the two does not become too small, so that excessive separation of fluorine oil does not occur, and it becomes difficult for excess fluorine oil to be supplied to the surface. As a result, adverse effects such as uneven gloss of the image, deterioration of adhesion between the elastic layer and the surface layer, and peeling can be further suppressed.

The amount of fluorooil contained in the elastic layer is preferably 1 phr or more and 50 phr or less, more preferably 5 phr or more and 40 phr or less, based on the weight of the fluororubber in the elastic layer. If it is 1 phr or more, the releasability is unlikely to decrease even after long-term use. When it is 50 phr or less, the adhesion between the elastic layer and the adhesive layer described later becomes better and it becomes difficult to peel off, and the oil existing on the surface is less likely to become excessive, and the occurrence of adverse effects such as uneven image gloss can be further suppressed.

The elastic layer may contain a heat conductive filler such as an inorganic oxide, boron nitride, carbon black, or carbon fiber, if necessary, for the purpose of improving the heat conductivity and the like.

The thickness of the elastic layer is preferably 100 μm or more and 500 μm or less, particularly 200 μm or more and 400 μm or less, from the viewpoint of contributing to the surface hardness and the efficiency of heat conduction to the unfixed toner at the time of fixing.

Further, an adhesive layer may be provided between the elastic layer and the surface layer, if necessary. Since the fluorine oil stored in the elastic layer needs to be transferred to the surface, the adhesive layer is preferably made of a fluorine-based primer material. The thickness of the adhesive layer is preferably 1 μm or less.

According to the fixing member described above, a small amount of fluorine oil can be supplied to the surface of the fixing member in a controlled state. Therefore, the transfer of excess fluorine oil to the surface of the fixing member is suppressed, the harmful effects caused by this excess fluorine oil can be suppressed, and excellent toner releasability higher than that of a commonly used fluororesin is realized. can do. Furthermore, since the fluorine oil is supplied from the elastic layer for a long period of time, an external supply system for the fluorine oil is not required, and the toner does not need to contain wax, so that the wax content of the toner is reduced or zero. Therefore, it is possible to suppress the harmful effects caused by wax in the toner. In the conventional fixing member, if the amount of oil supplied to the fixing member is large, there is a problem that other members in contact with the fixing member are contaminated. However, a small amount of fluorine oil is applied to the surface of the fixing member. Since it is supplied, the problem of such pollution can be solved.

[Fixing device]
Next, the fixing device according to the embodiment of the present invention will be described.
FIG. 2 is a cross-sectional view showing an example of a fixing device according to an embodiment of the present invention. The fixing device of the present invention is not limited to the example shown in FIG.

The fixing device 100 includes a fixing roller 10 which is a fixing member described above, a halogen heater 15 built in the fixing roller 10, and a pressure roller 20.
In the pressure roller 20, an elastic layer 22 containing heat-resistant rubber and a mold release layer 23 are sequentially laminated on the core metal 21. The pressure roller 20 is in pressure contact with the fixing roller 10 to form a nip portion. At this time, when the recording medium P to which the toner T is attached passes through the nip portion, the toner T attached to the recording medium P is heated by the fixing roller 10 to be softened and pressurized. It is fixed on the recording medium P.

[Electrophotograph image forming apparatus]
Further, FIG. 3 is a cross-sectional view showing an example of an electrophotographic image forming apparatus according to an embodiment of the present invention, and shows an electrophotographic image forming apparatus using the above-mentioned fixing member for electrophotographic.
In FIG. 3, the cylindrical electrophotographic photosensitive member (image carrier) 301 is rotationally driven at a predetermined peripheral speed in the arrow direction (clockwise direction) about the axis 302.

The surface (peripheral surface) of the rotationally driven electrophotographic photosensitive member 301 is charged to a positive or negative potential by the charging device 303, and then the exposure light (image exposure light) 304 emitted from the exposure device (not shown). Receive. In this way, an electrostatic latent image corresponding to the target image is formed on the surface of the electrophotographic photosensitive member 301. Examples of the charging device include a corona charging device using a corotron, a scorotron, and the like, a contact charging device using a roller, a brush, a film, and the like. Further, the voltage applied to the charging device may be only a DC voltage or a DC voltage on which an AC voltage is superimposed. Examples of the exposure apparatus include slit exposure, laser beam scanning exposure, and the like.

The electrostatic latent image formed on the surface of the electrophotographic photosensitive member 301 is developed with toner by the developing device 305 to become a toner image. Examples of the developing method include a method of developing by contacting or non-contacting magnetic or non-magnetic one-component or two-component toner.

The toner image formed on the surface of the electrophotographic photosensitive member 301 is sequentially transferred to the recording medium (paper or the like) P by the transfer device 306. The recording medium P is taken out and fed from the recording medium supply device (not shown) between the electrophotographic photosensitive member 301 and the transfer device 306 (contact portion) in synchronization with the rotation of the electrophotographic photosensitive member 301. ..

The recording medium P on which the toner image is transferred is separated from the surface of the electrophotographic photosensitive member 301, introduced into the above-mentioned fixing device 100 which is a fixing device, and undergoes image fixing to obtain an image forming product (print, copy). ) Is printed out of the electrophotographic device.

The surface of the electrophotographic photosensitive member 301 after the toner image is transferred is subjected to removal of transfer residual toner by a cleaning blade 309, which is a cleaning device, and then statically eliminated by pre-exposure light 311 from a pre-exposure device (not shown). It is processed and used repeatedly for image formation.

Further, the electrophotographic photosensitive member 301, the charging device 303, the developing device 305, and the cleaning blade 309 are integrally supported by the process cartridge 310 to form a cartridge. The process cartridge 310 can be attached to and detached from the electrophotographic image forming apparatus main body by using a guiding means 308 such as a rail of the electrophotographic image forming apparatus main body.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited thereto.
The fixing members produced in Examples and Comparative Examples were measured and evaluated by the following measurement methods and evaluation methods.

[Adhesion amount]
A crystal oscillator is placed on the stage of the tack tester TAC-1000 (manufactured by Reska Co., Ltd.), and the fixing member attached to the probe portion of the tack tester is pressed against the oscillator from above to reduce the amount of fluorine oil adhering. Quantified.

As the crystal oscillator, 6A202PN (manufactured by Piezo Parts Co., Ltd.) having a fundamental frequency of around 6 MHz was used. The frequency characteristics before and after adhesion are measured by using the QCM-A method (QCM based on Admittance method) to measure the changes in the series resonance frequency Fs before and after adhesion and the frequency Fw indicating the loss of vibration energy, and adhere from equation (a). The amount was calculated.

Specifically, first, pressing against the fixing member was carried out in advance, and fluorine oil was exuded on the surface of the fixing member. As it was, a fixing member in which the amount of fluorine oil existing in the surface layer in terms of mass was removed was prepared, and the state was used as a measurement sample. For the fixing member having no surface layer, the sample in the prepared state was used as the measurement sample.

The conditions for the tack test are as follows: a measurement sample cut out to a sample area of φ0.7 cm is attached to the probe, the pressure is 0.4 MPa, the pressing time is 50 msec, and the pressing amount is constant so that the transfer of the crystal oscillator is uniform. It was pressed at a pressing and pulling speed of 1.0 mm / sec. The temperature was set under the condition that the probe set temperature was 180 ° C.

[Surface free energy]
The contact angles for pure water, hexadecane, and diiodomethane were measured, and the values calculated based on the Kitazaki-hata formula were used. As the contact angle, DM-701 (manufactured by Kyowa Interface Science Co., Ltd.) was used, and the value of 1.8 μL of the droplet and the value 1 second after the impact of the droplet was used. The θ / 2 method was used to calculate the value. The surface free energy was calculated from the contact angles with respect to the above three liquids using the attached software (FAMAS 3.5.5, manufactured by Kyowa Interface Science Co., Ltd.).

[Film thickness]
The film thickness was calculated by cutting out the surface layer of the produced fixing member and observing the cut out film cross section with an SEM (S-4800, manufactured by Hitachi High-Technologies Corporation).

[Average pore size]
The average pore diameter was calculated by observing the surface of the prepared fixing member by SEM (S-4800, manufactured by Hitachi High-Technologies Corporation). The vacant part and the non-vacant part of the image observed at 50,000 times are binarized, the maximum diameter of the vacant part is fixed as the major axis direction, the minor axis is newly set, and the vacant part When an ellipse having an area equal to the area was set, the average value of the major axis and the minor axis of the ellipse was taken as the pore diameter. The average value of the 30 pores was obtained and used as the average pore diameter of the fixing member (in the surface layer).

[Heat-resistant]
For heat resistance, the weight loss rate when the sample was heated at 250 ° C. for 1 hour in the air was evaluated. The measurement was performed using a differential scanning calorimetry apparatus (DSC823, manufactured by METTLER TOLEDO Co., Ltd.). The criteria for evaluating heat resistance are shown below.
(Evaluation criteria)
A: Weight loss rate is less than 1% B: Weight loss rate is 1% or more and less than 5% C: Weight loss rate is 5% or more and less than 10% D: Weight loss rate is 10% or more

[Evaluation of toner offset resistance]
The fixing members obtained in Examples and Comparative Examples were mounted on a modified Canon copier "iRC3200". Separately, 10,000 sheets of 10 cm × 10 cm toner unfixed images (toner amount 0.6 g / cm ² ) were prepared on A4 size paper, and the offset property was evaluated by the above-mentioned copying machine. The toner used did not contain a release agent (wax, oil, etc.) component. The test conditions are as follows.
(Test condition)
Toner: Cy toner for iRC3200 (does not contain mold release agent component)
Paper: Canon Paper PB
Fixing temperature: 180 ° C
Transport speed: 300 mm / sec

When the number of sheets fixed in the fixing device reached 10,000, the surface of the fixing roller was visually observed to confirm the presence or absence of toner offset. In addition, a blank sheet of paper was passed through the fixing device, and the presence or absence of toner transferred from the surface of the fixing roller to the blank paper was visually confirmed. The criteria for evaluating the toner offset resistance are shown below.
(Evaluation criteria)
A: There is neither toner offset nor toner transferred on a blank sheet of paper.
B: A small amount of toner offset and toner transferred on a blank sheet are confirmed on either one.
C: Both the toner offset and the toner transferred on the blank sheet are confirmed.
D: Both the toner offset and the toner transferred on the blank sheet are confirmed from the first fixed sheet.

[Evaluation of uneven density]
Under the above test conditions, a halftone unfixed image was prepared, and the image fixed with the fixing member in the initial state was visually observed to evaluate the homogeneity and the degree of unevenness of the halftone image. The criteria for evaluating density unevenness are shown below.
(Evaluation criteria)
A: No density unevenness is observed in the halftone image.
B: Density unevenness of the halftone image is slightly observed in a part of the image.
C: Density unevenness of the halftone image is observed in about half of the image.
D: Density unevenness of the halftone image is observed on almost the entire surface of the image.

[Evaluation of uneven image gloss]
In the evaluation of the gloss unevenness of the fixed image, the gloss unevenness of the solid fixed image of the 10,000th fixed sheet was visually evaluated. The criteria for evaluating image gloss unevenness are shown below.
(Evaluation criteria)
A: No gloss unevenness in the solid image B: Slight gloss unevenness in a part of the solid image C: Glossy unevenness in about half of the solid image D: Glossy unevenness over the entire surface of the solid image.

[Evaluation of wrinkles on the surface]
During the durability test under the above conditions, the presence or absence of wrinkles generated in the circumferential direction on the surface layer of the fixing member was visually evaluated. The criteria for evaluating wrinkles on the surface are shown below.
(Evaluation criteria)
A: No wrinkles could be confirmed even after fixing 10,000 sheets.
B: Minor wrinkles were generated after fixing 10,000 sheets.
C: Wrinkles occurred when less than 1,000 sheets were fixed.
D: Wrinkles were generated or the surface layer was peeled off at the stage when one sheet was fixed.

(Example 1)
[Preparation of elastic layer]
Mix 100 parts by mass of liquid fluoroelastomer (SIFEL2662, manufactured by Shin-Etsu Chemical Co., Ltd.) and 10 parts by mass of fluorine oil (Demnum S-200, manufactured by Daikin Industries, Ltd., kinematic viscosity = 500 cSt (20 ° C.)) and stir. Using a defoaming device (AR-250, Shin-Etsu Chemical Co., Ltd.), stirring was carried out for 10 minutes and defoaming was carried out for 1 minute to obtain an elastic layer material liquid.
The obtained elastic layer material liquid is applied onto a substrate (thickness 35 μm, diameter 24 mm) made of SUS (stainless steel) so that the thickness of the cured rubber becomes 300 μm, and then 200 ° C. An elastic layer was formed by curing under the condition of 4 hours.

[Preparation of surface layer]
An amorphous fluororesin solution having the structure of the formula (1) (Somaflon B1, manufactured by SOMAR Corporation) was applied onto the elastic layer by a spray coating method. Then, it was put into a drying oven and heated at 110 degreeC for 10 minutes. A surface layer was formed by further heating at 250 ° C. for 10 minutes. In the process of forming the surface layer, the fluorine oil in the elastic layer shifts to the communication holes formed in the surface layer as the surface layer is formed. As a result, the film thickness of the produced surface layer was 95 nm, the pore diameter was 90 nm, and the surface free energy was 12.1 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 7.4 × 10 ² ng. When the heat resistance of the fluorine oil used was confirmed, the weight loss rate was 0.4%.

The surface of the fixing member obtained by forming the surface layer was observed by SEM (S-4800, manufactured by Hitachi High-Technologies Corporation) under the conditions of a magnification of 50,000 times and an acceleration voltage of 1.0 kV. FIG. 4 shows an SEM image of the surface of the fixing member according to this embodiment.

(Example 2)
Fixing in the same manner as in Example 1 except that the resin concentration of the amorphous fluororesin solution in Example 1 was halved using a fluorine solvent (Bertrel Suprion, manufactured by Mitsui DuPont Fluorochemical Co., Ltd.). A member was produced.
The prepared surface layer had a film thickness of 93 nm and a pore diameter of 186 nm. The surface free energy was 11.8 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 2.3 × 10 ³ ng.

(Example 3)
As the amorphous fluororesin solution in the preparation of the surface layer in Example 1, an amorphous fluororesin (ALGOFLON AD40H, manufactured by Solvay Co., Ltd.) having the structure of the formula (2) was used instead of Somaflon B1. Made a fixing member in the same manner as in Example 1. The film thickness of the prepared surface layer was 87 nm, and the pore diameter was 93 nm. The surface free energy was 12.4 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 8.4 × 10 ² ng.

(Example 4)
As the amorphous fluororesin solution in the preparation of the surface layer in Example 1, an amorphous fluororesin solution having the structure of the formula (3) (Cytop Type, manufactured by Asahi Glass Co., Ltd.) was used instead of Somaflon B1. A fixing member was produced in the same manner as in Example 1 except that the fixing member was prepared. The film thickness of the prepared surface layer was 89 nm, and the pore diameter was 93 nm. The surface free energy was 12.3 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 6.4 × 10 ² ng.

(Example 5)
A fixing member was prepared in the same manner as in Example 1 except that Fomblin M60 (manufactured by Solvay Co., Ltd., kinematic viscosity = 550 cSt (20 ° C.)) was used instead of Demnum S-200 as the fluorine oil in Example 1. did. The prepared surface layer had a film thickness of 97 nm and a pore diameter of 89 nm. The surface free energy was 11.5 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 4.1 × 10 ³ ng. When the heat resistance of the fluorine oil used was confirmed, the weight loss rate was 0.2%.

(Example 6)
A fixing member was prepared in the same manner as in Example 1 except that Krytox107 (The Chemours Company, kinematic viscosity = 1600 cSt (20 ° C.)) was used instead of Demnum S-200 as the fluorine oil in Example 1. The prepared surface layer had a film thickness of 90 nm and a pore diameter of 96 nm. The surface free energy was 12.1 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 3.9 × 10 ² ng. When the heat resistance of the fluorine oil used was confirmed, the weight loss rate was 0.6%.

(Example 7)
In Example 1, a fixing member was produced in the same manner as in Example 1 except that the amount of fluorine oil was 2 parts by mass. The film thickness of the prepared surface layer was 94 nm, and the pore diameter was 88 nm. The surface free energy was 12.6 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 1.7 × 10 ² ng.

(Example 8)
In Example 1, a fixing member was produced in the same manner as in Example 1 except that the amount of fluorine oil was 6 parts by mass. The prepared surface layer had a film thickness of 96 nm and a pore diameter of 91 nm. The surface free energy was 12.2 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 6.5 × 10 ² ng.

(Example 9)
In Example 1, a fixing member was produced in the same manner as in Example 1 except that the amount of fluorine oil was 35 parts by mass. The prepared surface layer had a film thickness of 95 nm and a pore diameter of 85 nm. The surface free energy was 12.0 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 7.9 × 10 ² ng.

(Example 10)
In Example 1, a fixing member was produced in the same manner as in Example 1 except that the amount of fluorine oil was 48 parts by mass. The prepared surface layer had a film thickness of 97 nm and a pore diameter of 98 nm. The surface free energy was 11.9 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 1.4 × 10 ³ ng.

(Example 11)
A fixing member was produced in the same manner as in Example 1 except that Demnum S-65 (manufactured by Daikin Industries, Ltd.) was used instead of Demnum S-200 as the fluorine oil in Example 1. The film thickness of the prepared surface layer was 92 nm, and the pore diameter was 93 nm. The surface free energy was 12.4 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 7.8 × 10 ² ng. When the heat resistance of the fluorine oil used was confirmed, the weight loss rate was 8.3%.

(Comparative Example 1)
[Preparation of elastic layer]
A liquid fluoroelastomer (SIFEL2662, manufactured by Shin-Etsu Chemical Co., Ltd.) is applied onto a substrate (thickness 35 μm, diameter 24 mm) formed of SUS so that the thickness after curing is 300 μm, and then 200 ° C. -The elastic layer was formed by curing under the condition of 4 hours.

[Preparation of surface layer]
An amorphous fluororesin solution having the structure of the formula (1) (Somaflon B1, manufactured by SOMAR Corporation) was applied to the elastic layer by a spray coating method. Then, it was put into a drying oven and heated at 110 degreeC for 10 minutes. A surface layer was formed by further heating at 250 ° C. for 10 minutes. In this comparative example, since the elastic layer does not contain fluorine oil, the transfer of fluorine oil from the elastic layer to the surface layer does not occur in the process of forming the surface layer. The prepared surface layer had a film thickness of 95 nm and a pore diameter of 99 nm. The surface free energy was 13.1 mJ / m ² .

(Comparative Example 2)
As the amorphous fluororesin solution in the preparation of the surface layer in Comparative Example 1, an amorphous fluororesin solution having the structure of the formula (3) (Cytop Type, manufactured by Asahi Glass Co., Ltd.) was used instead of Somaflon B1. A fixing member was produced in the same manner as in Comparative Example 1 except that the fixing member was prepared. The film thickness of the prepared surface layer was 91 nm, and the pore diameter was 91 nm. The surface free energy was 13.4 mJ / m ² .

(Comparative Example 3)
In Example 1, the fixing member was produced in the same manner as in Example 1 except that only the elastic layer was produced without forming the surface layer. The surface free energy was 12.1 mJ / m ² . When the amount of adhesion was measured, it was 9.3 × 10 ³ ng.

(Comparative Example 4)
In Comparative Example 3, a fixing member was produced in the same manner as in Comparative Example 3 except that Fomblin M60 (manufactured by Solvay Co., Ltd.) was used instead of Demnum S-200 as the fluorine oil. The surface free energy was 12.2 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 21.8 × 10 ³ ng.

(Comparative Example 5)
In Example 1, a fixing member was produced in the same manner as in Example 1 except that fluorine oil (Demnum S-200, manufactured by Daikin Corporation) was applied and impregnated only on the surface layer after the fixing member was produced. The prepared surface layer had a film thickness of 96 nm and a pore diameter of 91 nm. The surface free energy was 12.3 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 7.6 × 10 ² ng.

(Comparative Example 6)
A fixing member was produced in the same manner as in Example 1 except that Fluorolink MD700 (manufactured by Solvay Co., Ltd.) was used instead of Demnum S-200 as the fluorine oil in Example 1. The prepared surface layer had a film thickness of 97 nm and a pore diameter of 90 nm. The surface free energy was 12.0 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 5.8 × 10 ³ ng.

(Comparative Example 7)
As the surface layer in Example 1, a fixing member was produced in the same manner as in Example 1 except that a dispersion coating material of PFA particles (AW-5000L, manufactured by Daikin Industries, Ltd.) was heat-cured and laminated. The film thickness of the prepared surface layer was 99 nm, and no pores could be confirmed. The surface free energy was 18.1 mJ / m ² . The amount of adhesion was below the measurement limit.

(Comparative Example 8)
A fixing member was produced in the same manner as in Example 1 except that a porous PTFE resin (Poaflon, manufactured by Sumitomo Electric Fine Polymer Co., Ltd., pore diameter 220 nm) was laminated as the surface layer in Comparative Example 6. The prepared surface layer had a film thickness of 1.2 μm and a pore diameter of 220 nm. The surface free energy was 12.3 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 6.2 × 10 ³ ng.

(Comparative Example 9)
A fixing member was produced in the same manner as in Example 1 except that a porous PTFE resin (Poaflon, manufactured by Sumitomo Electric Fine Polymer Co., Ltd., pore diameter 1210 nm) was laminated as the surface layer in Comparative Example 6. The film thickness of the prepared surface layer was 7.8 μm, and the pore diameter was 1200 nm. The surface free energy was 12.1 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 28.5 × 10 ³ ng.

(Comparative Example 10)
In Example 1, a fixing member was produced in the same manner as in Example 1 except that the amount of fluorine oil was 0.80 parts by mass. The prepared surface layer had a film thickness of 93 nm and a pore diameter of 89 nm. The surface free energy was 13.0 mJ / m ² . Moreover, when the amount of adhesion was measured, it was 0.98 × 10 ² ng.

(Comparative Example 11)
In Example 1, a fixing member was produced in the same manner as in Example 1 except that the amount of fluorine oil was 55 parts by mass. A uniform surface layer could not be produced, and subsequent evaluation could not be performed.

Table 1 summarizes the above examples and comparative examples. Table 2 shows the evaluation results of the fixing members produced in Examples and Comparative Examples.

From the above results, the following can be seen. That is, according to the present invention, by supplying fluorooil having high releasability to the surface layer having a porous structure made of fluororubber, even a toner with reduced wax can be released for a long period of time. It is possible. Further, since the pore diameter of the surface layer is fine, the amount of fluorine oil supplied to the surface can be controlled, and therefore, adverse effects such as toner offset and image deterioration due to the oil component can be suppressed. Understand.

10 Fixing roller 11 Base layer 12 Elastic layer 13 Surface layer 15 Halogen heater 20 Pressurizing roller 21 Core metal 22 Elastic layer 23 Release layer 100 Fixing device T Toner P Recording medium

Claims (9)

An electrophotographic fixing member having a base layer, an elastic layer, and a surface layer.
The elastic layer contains fluorooil having a perfluoropolyether structure and fluororubber.
The surface layer is composed of an amorphous fluororesin film having a cyclic perfluoropolyether structure.
The membrane has a porous structure with a plurality of pores, and the plurality of pores retain a fluorine oil having a perfluoropolyether structure.
The fixing member for electrophotographic is characterized in that the fixing member satisfies the following condition (i):
[Condition (i)] From the surface of the surface layer, at least a mass corresponding to the total mass of the fluorine oil contained in the surface layer is absorbed and removed, and subsequently, on the surface of the surface layer. On the other hand, when the detection surface of the quartz crystal microbalance (QCM) sensor is pressed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec, it adheres to ^{the unit area (1 cm 2) of the detection surface.} The mass of the deposit containing fluorine oil is 1.0 × 10 ² ng or more and ^{less than 5.0 × 10 3} ng. The first aspect of the present invention, wherein the amorphous fluororesin having a cyclic perfluoropolyether structure has any structure selected from the group consisting of the structures represented by the formulas (1) to (3). Fixing member:

(In equations (1) to (3), n ₁ ~ N ₃ And m ₁ ~ M ₃ Is an arbitrary integer of 1 or more, and may be appropriately selected according to the purpose, and is not particularly limited. For example, n ₁ Is 100 or more and 2000 or less, m ₁ Is 300 or more and 4500 or less, n ₂ Is 100 or more and 2000 or less, m ₂ Is 300 or more and 4500 or less, n ₃ Is 100 or more and 1500 or less, m ₃ Is 100 or more and 1500 or less. ). The fixing member according to claim 1 or 2, wherein the surface layer has a thickness of 10 nm or more and 20 μm or less. The average pore diameter before Kiana is is 1nm or more 200nm or less, fixing member according to any one of claims 1 to 3. Claim 1 that the absolute value of the difference in solubility parameter between the fluororubber contained in the elastic layer and the fluorooil contained in the elastic layer is 1 (MPa) ^0.5 or more and 13 (MPa) ^0.5 or less. The fixing member according to any one of Items to 4. The fixing member according to any one of claims 1 to 5, wherein the fluorine oil has a weight loss rate of less than 1.0% after being heated in the air at 250 ° C. for 1 hour. The fixing member according to any one of claims 1 to 6, wherein the amount of the fluorooil contained in the elastic layer is 1 phr or more and 50 phr or less with respect to the fluororubber in the elastic layer. A fixing device comprising the fixing member according to any one of claims 1 to 7. Image carrier and
A charging device for charging the image carrier and
An exposure apparatus that irradiates the charged image carrier with exposure light to form an electrostatic latent image.
A developing device that develops an electrostatic latent image formed on the image carrier with toner to form a toner image.
A transfer device that transfers a toner image formed on the image carrier to a recording medium,
It has a fixing device for fixing the toner image transferred to the recording medium, and has a fixing device.
An electrophotographic image forming apparatus, wherein the fixing device is the fixing device according to claim 8.

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