JP2018180488A - Fixing member for electrophotography, fixing device and electrophotographic image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing member, a fixing device and an electrophotographic image forming device for electrophotographic which are excellent in toner releasability and can form a high-quality fixing image for a long period of time. SOLUTION: The base layer, a fluorine oil having a perfluoropolyether structure, an elastic layer containing a fluorine rubber, a fluororesin, and a fluorine oil having a perfluoropolyether structure are contained, and a plurality of holes are formed. A fixing member for electrophotographic having a surface layer having a porous structure and having. [Selection diagram] Fig. 1

Description

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

In the fixing process of an electrophotographic image forming apparatus, when the 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". A 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 applying mechanism to the surface of the fixing roller, and a cleaning unit that contacts the pressure roller. doing.

JP 10-10904 A

The oil application mechanism to the surface of the fixing roller according to Patent Document 1 can be an obstacle to downsizing of the electrophotographic image forming apparatus. Therefore, the present inventors have recognized that it is necessary to develop a fixing member capable of maintaining high toner releasability over a long period of time regardless of an apparatus such as an oil application mechanism.
Therefore, one aspect of the present invention is directed to the provision of a fixing member for electrophotography which is excellent in toner releasability and can form a high-quality fixed image over a long period of time.
Another aspect of the present invention is directed to providing a fixing device and an electrophotographic image forming apparatus capable of stably forming a high quality electrophotographic image.

According to one aspect of the present invention, there is provided a fixing member for electrophotography comprising a base layer, an elastic layer, and a surface layer,
The elastic layer contains a fluorine oil having a perfluoropolyether structure and a fluorine rubber,
The surface layer includes a fluorine resin and a fluorine oil having a perfluoropolyether structure, and has a porous structure having a plurality of pores,
The fixing member is provided with a fixing member for electrophotography which satisfies the following condition (i):
[Condition (i)] From the surface of the surface layer, at least a fluorine oil having a perfluoropolyether structure having a mass corresponding to the mass of the fluorine oil having a perfluoropolyether structure contained in the surface layer is absorbed 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 and a temperature of 180 ° C. for 50 msec. The mass of the deposit including a fluorine oil having a perfluoropolyether structure attached to a unit area (1 cm ² ) of the detection surface is 1.0 × 10 ² ng or more and less than 5.0 × 10 ³ ng.

According to another aspect of the present invention, there is provided a fixing device having the above-mentioned fixing member.
According to still another aspect of the present invention, an image carrier, a charging device for charging the image carrier, and an exposure device for forming an electrostatic latent image by irradiating the charged image carrier with exposure light A developing device for developing an electrostatic latent image formed on the image carrier with toner to form a toner image; a transfer device for transferring a toner image formed on the image carrier onto a recording medium; There is provided an electrophotographic image forming apparatus, comprising: a fixing device for fixing a toner image transferred to a medium, wherein the fixing device is the above-mentioned fixing device.

According to one aspect of the present invention, it is possible to obtain a fixing member for electrophotography which is excellent in toner releasability and can form a high-quality fixed image over 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 apparatus capable of stably forming a high quality electrophotographic image.

FIG. 3 is a cross-sectional view showing an example of a fixing member according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an example of a fixing device according to an embodiment of the present invention. FIG. 1 is a cross-sectional view showing an example of an electrophotographic image forming apparatus according to an embodiment of the present invention. 7 is a SEM image of the surface of the fixing member according to Example 1;

The inventors of the present invention have made studies on carrying the function of gradually supplying fluorine oil having excellent releasability to the surface of the fixing member on the fixing member itself in direct contact with the unfixed toner. As a result, it was found that by providing a fixing layer having an elastic layer and a surface layer, each having the following functions, fluorine oil having excellent releasability is gradually supplied (released) to the surface of the fixing member. The
That is, the elastic layer has a function as a storage layer of oil by being configured such that fluorine oil is appropriately held in the layer. In addition, the surface layer is provided on the outer surface of the elastic layer, and by including 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. Have 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 in the surface layer and is gradually released to the surface of the fixing member, so the fluorine oil can be prolonged It has been found that it can be supplied to the surface of the fixing member over the

[Fixing member for electrophotography]
Hereinafter, a fixing member for electrophotography according to an embodiment of the present invention will be described in detail with reference to FIG.
FIG. 1 is a cross-sectional view in a direction orthogonal to the longitudinal direction of a fixing member 10 having a roller shape (hereinafter, also referred to as “fixing roller”) according to an aspect of the present invention. The shape of the fixing member is not limited to the roller shape, and 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 fluorine oil having a perfluoropolyether structure and a fluorine rubber. In addition, the surface layer 13 includes a fluorine resin 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)] A fluorine oil having a perfluoropolyether structure of a mass corresponding to the total mass of at least 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 for 50 msec at a temperature of 180 ° C. under a pressure of 0.4 MPa, a unit of the detection surface. The mass of the deposit including the fluorine oil having a perfluoropolyether structure attached to the area (1 cm ² ) is 1.0 × 10 ² ng or more and less than 5.0 × 10 ³ ng.
That is, satisfying the condition (i) means that the pressure of 0. 5 is satisfied even if 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. By fixing under general fixing conditions such as 4 MPa, a temperature of 180 ° C., and a pressing time of 50 msec, the fluorinated oil having a perfluoropolyether structure stored in the elastic layer 12 is transferred to the surface layer 13. The amount of fluorine oil having a perfluoropolyether structure attached from the surface of the surface layer 13 to the object to be fixed (fixed image) is technically controlled within an appropriate range.

  Here, the elastic layer 12 containing fluorine oil having a perfluoropolyether structure functions as a storage layer of fluorine oil. Further, the surface layer 13 has a porous structure having a plurality of pores, and functions as a layer having oil permeability, so that the fluorine oil in the elastic layer 12 passes through the porous structure. Transfer to the surface of the fixing member 10. The fluorine oil in the elastic layer 12 and the fluorine oil initially held in a porous structure are transferred to the surface of the fixing member 10 and function as a toner release agent. At this time, since the pore diameter of the porous structure is fine, the amount of oil transferred to the surface of the fixing member 10 can be controlled to be small. Also, even after the fluorine oil initially retained in the porous structure disappears for long-term use, the elastic layer 12 supplies the fluorine oil from the elastic layer 12 by the application of heat and pressure. Releasability can be secured. Furthermore, since the amount of the 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 fixed image generated due to the presence of the fluorine oil in excess.

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

(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 sometimes simply referred to as a 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 It is appropriately selected from those having only a linear structure, such as (OCF (CF ₃ ) CF ₂ ) _m (OCF ₂ ) _n OR _f , or a part of branched structures. Here, each R _f represents an arbitrary perfluoroalkyl group. m and n each independently represent an arbitrary integer of 1 to 200. Among these, those having heat resistance are particularly preferable. For example, the weight loss after heating at 250 ° C. in the atmosphere for 1 hour is preferably less than 10%, more preferably less than 5.0%, particularly preferably less than 1.0%. preferable.

(Surface layer)
The surface layer includes a fluorine resin and a fluorine oil having a perfluoropolyether structure, and has a porous structure having a plurality of pores. The fluorine oil is held in the pores of the porous structure, and a part thereof is transferred to the surface of the surface layer at the time of fixing, and is lost from the surface layer by being attached to the material to be fixed (fixed image). On the other hand, since part of the fluorine oil stored in the elastic layer migrates to the surface layer at the time of fixing, new fluorine oil is supplied into the pores of the porous structure and held in the pores. Therefore, although the fluorine oil held in the pores of the porous structure in the initial state (when not in use) is gradually lost as it is used, the new fluorine oil is replenished from the elastic layer, The state in which the fluorine oil is held in the pores of the porous structure is maintained for a long time.

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

  Among them, non-crystalline fluororesins having a cyclic perfluoropolyether structure (cyclic perfluoropolyether structure from the viewpoint of high chemical affinity with a fluorine oil having a perfluoropolyether structure and excellent film formability from a solution state Fluoropolyether resins are preferred.

  As a result of intensive investigations by the present inventors, it was found that when an amorphous fluororesin having a cyclic perfluoropolyether structure is formed into a film, it becomes a porous body having a fine pore diameter. It is believed that this is likely to cause phase separation between the resin component and the solvent in the process of evaporation of the solvent from the solution state, with the result that pores are formed. Therefore, the pore diameter 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 amount of surface migration of the fluorine oil to a very small amount, the present invention has been completed.

  In addition, since the chemical affinity between the non-crystalline fluorine resin having a cyclic perfluoropolyether structure and the fluorine oil is high, the fluorine oil does not easily disappear from the surface layer even if it is subjected to contact and rubbing at the fixing nip, Durability is improved. Furthermore, since an amorphous fluorocarbon resin having a cyclic perfluoropolyether structure is formed into a film from a solution state, it is easy to stack, and when it is applied, a part of the layer penetrates into the lower layer and hardens in that state. Improve.

The amount of fluorine oil having a perfluoropolyether structure on the surface of the surface layer can be measured using a quartz oscillator. The quartz oscillator has a sensitivity capable of measuring a mass on the order of ng to μg. The quartz crystal has a structure in which a crystal of quartz is cut on a very thin plate and metal thin films are attached to both sides, and when an alternating electric field is applied to the metal electrodes on both sides, a constant frequency (resonance It has the property of oscillating at frequency). Since the resonance frequency decreases in proportion to the mass of the substance when a trace amount of substance is adsorbed on the metal thin film, it can be used as a microbalance. It is known that the amount of change in frequency and the mass of the attached substance on the electrode follow the Sauebrey equation (Equation (a)) below.
(ΔF: frequency change, Δm: mass change, F ₀ : fundamental frequency, _{Q Q} : density of quartz, μ _Q : shear stress of quartz, A: electrode area)
This measurement method is also referred to as Quartz Crystal Microbalance (QCM) method.

As a result of intensive investigations, the present inventors have found the amount of fluorine oil on the surface of the fixing member which is extremely suitable, and have made the present invention. That is, it has been found that the desired effect can be obtained by setting the amount of fluorine oil calculated by the following method to a suitable range.
Specifically, first, a quartz oscillator is placed on the stage of a tack tester TAC-1000 (manufactured by Lesca Co., Ltd.), and a fixing member attached to a probe of the tack tester is pressed from above onto the oscillator. When pressing the fixing member, the pressure was 0.4 MPa, pressing time was 50 msec, pressing amount constant mode, pressing and pulling up speed was 1.0 mm / sec, and probe setting temperature was 180 ° C. And at this time, the adhesion amount of fluorine oil having a perfluoropolyether structure attached to a unit area (1 cm ² ) of the quartz crystal detection surface is 1.0 × 10 ² ng or more and 5.0 × 10 ³ ng or more Less than.

The above-mentioned pressing conditions conform to the conditions in the fixing nip, and when the adhesion amount is in the above-mentioned range, the fixing conditions do not have the harmful effect due to the fluorine oil even in long-term use in a real machine. If the adhesion amount is less than 1.0 × 10 ² ng, the releasability is reduced, so that toner offset is likely to occur, and image degradation is likely to occur. Further, if the adhesion amount is 5.0 × 10 ³ ng or more, toner offset due to excess fluorine oil and gloss unevenness due to transfer of excess fluorine oil to an image tend to occur.

  Here, the surface layer includes the fluorine oil contained in the elastic layer so that the deposit attached to the detection surface includes the fluorine oil having a perfluoropolyether structure contained in the elastic layer. It is preferable to be allowed to pass through in the thickness direction of the surface layer. That is, it is preferable that the surface layer has oil permeability which allows the fluorine oil having the perfluoropolyether structure in the elastic layer to permeate.

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

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 they may be appropriately selected depending on the 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, m ₃ is 100 or more and 1500 or less is there.

  The average pore diameter 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. It is preferable that the average pore diameter is 1 nm or more, because the migration of the fluorine oil to the surface of the fixing member is high, and the releasability is unlikely to be reduced by long-term use. 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, and toner offset, image density unevenness, and gloss unevenness are suppressed, and toner particles hardly enter the holes and to the fixing member. It is possible to suppress the generation of residual toner.

  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, disappearance of the surface layer due to durable wear is suppressed. By the presence of the surface layer, it is possible to suppress the exposure of the elastic layer which supplies excess fluorine oil to the contact object on the surface, and it is also possible to 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 heat source inside the fixing member can be sufficiently transmitted to the toner.

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

Surface layer is preferably the surface free energy is 10 mJ / ^{m 2} to 15 mJ / ^{m 2,} and more preferably 10 mJ / ^{m 2} to 15 mJ / ^{m 2.}

(Elastic layer)
The elastic layer contains a fluorine oil having a perfluoropolyether structure and a fluorine rubber.
It is preferable that the fluororubber has high affinity to the fluorine oil 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 modifying these silicones are suitably used. Used. Examples of binary and ternary vinylidene fluoride-based fluororubbers include Daiel (manufactured by Daikin Industries, Ltd.), Viton, Kalrez (all manufactured by DuPont), and the like. As silicone modified fluororubber, SIFEL (made by Shin-Etsu Chemical Co., Ltd.) etc. are mentioned, for example.
Further, in view of ease of molding at the time of forming the elastic layer and heat curing property, it is preferable to be formed from liquid addition type fluororubber. In addition, these fluororubbers may be formed from any type of 1 liquid and 2 liquids.

  The elastic layer is a layer containing a fluorine oil having a perfluoropolyether structure. There is no particular limitation on the method of including fluorine oil in the elastic layer, and fluorine oil may be added to liquid fluororubber, and then the fluorine rubber may be cured, or fluorine oil after being cured is fluorine oil. May be impregnated.

  The fluorine oil contained in the elastic layer preferably has controlled chemical affinity with the fluorine rubber constituting the elastic layer. 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 serves as a measure of the affinity of two or more substances, and is a parameter represented by the square root of molecular cohesive energy. In the present invention, the SP value is derived using the method of Hansen. Here, the method of Hansen represents the energy of one substance by the three components of dispersion energy term (δ _D ), polarization energy term (δ _P ), and hydrogen bond energy term (δ _H ), and is a vector in a three-dimensional space Is represented as If the difference between the SP values of the two substances is small (the distance between the two substances is short), it indicates that the two substances have high solubility, that is, they are easily miscible. On the other hand, when the difference between the SP values of the two substances is large (the distance between the two substances is long), it indicates that the two substances have low solubility, that is, they are hardly miscible.

In the present invention, δ _D , δ _P , δ _H, and parameters for each substituent used in calculation by the group contribution method are the 3rd edition 3 of the database-equipped computer software “HSPiP” developed and marketed by the Hansen Group. Calculate using 1.1.4. At this time, the SP value of each component is calculated based on the following equation (b).
SP value ^{_{= (δ D 2 + δ P}} 2 + δ H 2) 0.5 (b)

Moreover, the difference ((DELTA) SP) of the solubility parameter in two types of components shall be defined by the distance in the said three-dimensional space, and the value is computed 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 parameter between the fluorine oil contained in the elastic layer and the fluorine resin contained in the elastic layer is preferably 1 (MPa) ^0.5 or more and 13 (MPa) ^0.5 or less. Preferably, it is 1 (MPa) ^0.5 or more and 7.5 (MPa) ^0.5 or less.

If ΔSP is 1 (MPa) ^0.5 or more, the interaction between the fluorine resin and the fluorine oil does not become too large, so when heat or pressure is applied to the fixing member at the time of nip, the fluorine oil is easily transferred to the surface. Good releasability can be exhibited. Further, if ΔSP is 13 (MPa) ^0.5 or less, the interaction between the two does not become too small, so excessive separation of the fluorine oil does not occur, and it becomes difficult to supply excess fluorine oil to the surface. As a result, it is possible to further suppress adverse effects such as unevenness in gloss of the image, and decrease in adhesion between the elastic layer and the surface layer, and peeling.

  The amount of fluorine oil 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 the amount is 1 phr or more, the releasability is unlikely to be reduced even by long-term use. If the amount is 50 phr or less, adhesion between the elastic layer and the adhesive layer described later becomes better and peeling becomes difficult, and oil present on the surface is unlikely to become excessive, and generation of adverse effects such as image gloss unevenness can be further suppressed.

  The elastic layer may contain a thermally conductive filler such as an inorganic oxide, boron nitride, carbon black, carbon fiber or the like, as necessary, for the purpose of improving the thermal 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 contribution to surface hardness and the efficiency of heat conduction to unfixed toner at the time of fixation.

  In addition, an adhesive layer may be provided between the elastic layer and the surface layer as needed. The adhesive layer is preferably made of a fluorine-based primer material because the fluorine oil stored in the elastic layer needs to migrate to the surface. The thickness of the adhesive layer is preferably 1 μm or less.

  According to the fixing member described above, it is possible to supply a small amount of fluorine oil 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, and the adverse effect due to the excess fluorine oil can be suppressed, and an excellent toner releasability higher than that of the fluorine resin usually used is realized. can do. Furthermore, since the fluorine oil is supplied from the elastic layer over a long period of time, an external supply system of the fluorine oil is unnecessary, and the toner does not need to contain wax, so the toner wax content can be reduced or zero. Thus, the harmful effects caused by the wax in the toner can be suppressed. In the conventional fixing member, there is also a problem that when the amount of oil supplied to the fixing member is large, the other members in contact with the fixing member are contaminated, but a small amount of fluorine oil is applied to the surface of the fixing member. Since it supplies, such a problem of contamination can also be solved.

[Fixing device]
Next, a fixing device according to an 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 the fixing roller 10 as the 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 a heat resistant rubber and a release layer 23 are sequentially laminated on a core metal 21. The pressure roller 20 is in pressure contact with the fixing roller 10, and a nip portion is formed. At this time, when the recording medium P to which the toner T adheres passes through the nip portion, the toner T adhering to the recording medium P is heated and softened by the fixing roller 10 and is pressurized, Fix the recording medium P.

[Electrophotographic image forming apparatus]
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 fixing member for electrophotography described above.
In FIG. 3, a cylindrical electrophotographic photosensitive member (image carrier) 301 is rotationally driven at a predetermined circumferential speed in the direction of the arrow (clockwise direction) around a shaft 302.

  The surface (circumferential surface) of the electrophotographic photosensitive member 301 which is rotationally driven is charged to a positive or negative potential by the charging device 303, and then 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 corotron, scorotron or the like, and a contact charging device using a roller, a brush, a film or 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. Further, as the exposure apparatus, for example, slit exposure, laser beam scanning exposure and the like can be mentioned.

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

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

  The recording medium P to which the toner image has been transferred is separated from the surface of the electrophotographic photosensitive member 301, and is introduced into the above-described fixing device 100, which is a fixing device, to undergo image fixing, thereby forming an image formed product (print, copy Printed out of the electrophotographic apparatus.

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

  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 is detachably attachable to the electrophotographic image forming apparatus main body by using guide means 308 such as a rail of the electrophotographic image forming apparatus main body.

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

[Attachment amount]
The quartz vibrator is placed on the stage of the tack tester TAC-1000 (made by Lesca Co., Ltd.), and the fixing member attached to the probe of the tack tester is pressed against the vibrator from the top, so that the amount of fluorine oil attached is It quantified.

  As the crystal unit, 6A 202 PN (manufactured by Piezo Parts Co., Ltd.) having a fundamental frequency of 6 MHz was used. Before and after attachment frequency characteristics measurement, QCM-A (QCM based on Admittance method) is used to measure changes in series resonance frequency Fs before and after attachment and frequency Fw representing loss of vibration energy. The amount was calculated.

  Specifically, first, pressing to the fixing member was performed in advance, and the fluorine oil was allowed to leak out to the surface of the fixing member. As it is, a fixing member in a state in which the fluorine oil in an amount equivalent to or more than the amount present in the surface layer was converted in terms of mass was removed, and the state was used as a measurement sample. In addition, about the fixing member which does not have a surface layer, the sample of the produced state was made into the measurement sample.

  As a condition of the tack test, a measurement sample cut into a sample area of φ0.7 cm is attached to a probe, a pressure is 0.4 MPa, a pressing time is 50 msec, a pressing amount constant mode, so that transfer of the crystal unit becomes uniform. The pressing and pulling speed was 1.0 mm / sec. The temperature was set at a probe set temperature of 180 ° C.

[Surface free energy]
The contact angles to pure water, hexadecane and diiodomethane were measured, and values calculated based on the Kitazaki-Kata (kitazaki-hata) equation were used. The contact angle was determined using DM-701 (manufactured by Kyowa Interface Science Co., Ltd.), and the droplet was 1.8 μL, and the value one second after the droplet was applied was used. The θ / 2 method was used to calculate the value. In addition, the surface free energy was calculated from the contact angle to the above three liquids with 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 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 produced fixing member by SEM (S-4800, manufactured by Hitachi High-Technologies Corporation). The holes and non-holes in the image observed at 50,000 times are binarized, the maximum diameter of the holes is fixed as the long axis direction, and the minor axis is newly set. The average value of the major axis and the minor axis of the ellipse when the ellipse having the area equal to the area was set was used as the hole diameter. The average value of 30 holes was determined, and this was taken as the average pore diameter of the fixing member (in the surface layer).

[Heat-resistant]
The heat resistance evaluated the weight loss rate when the sample was heated at 250 ° C. for 1 hour in the air. The measurement was performed using a differential scanning calorimeter (DSC 823, manufactured by METTLER TOLEDO Co., Ltd.). The criteria of heat resistance evaluation are shown below.
(Evaluation criteria)
A: Weight reduction rate less than 1% B: Weight loss rate less than 1% and less than 5% C: Weight loss rate less than 5% and less than 10% D: Weight loss rate less than 10%

[Toner offset resistance evaluation]
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 unfixed toner images (toner amount 0.6 g / cm ² ) were prepared on A4 size paper, and the offset property was evaluated in the copying machine. The toner used did not contain a releasing agent (wax, oil, etc.) component. The test conditions are as follows.
(Test conditions)
Toner: Cy toner for iRC3200 (without release agent component)
Paper: Canon paper PB
Fixing temperature: 180 ° C
Conveyance speed: 300 mm / sec

When the number of fixing sheets 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. Further, a white paper was passed through the fixing device, and the presence or absence of the toner transferred from the surface of the fixing roller to the white paper was visually confirmed. The criteria for the evaluation of the toner offset resistance are shown below.
(Evaluation criteria)
A: Toner offset and no toner transferred onto white paper.
B: Toner offset and a small amount of toner transferred onto the white paper are confirmed.
C: Both the toner offset and the toner transferred onto the white paper are confirmed.
D: Both the toner offset and the toner transferred onto the white sheet are confirmed from the first fixing sheet number.

[Density unevenness evaluation]
Under the test conditions, a halftone unfixed image was prepared, and the image fixed by the fixing member in the initial state was visually observed to evaluate the uniformity of the halftone image and the degree of unevenness. The criteria for evaluation of uneven density are shown below.
(Evaluation criteria)
A: Uneven density of the halftone image is not observed.
B: Density unevenness of the halftone image is slightly observed in part of the image.
C: Uneven density of halftone image is observed in about half of the image.
D: Uneven density of the halftone image is observed almost all over the image.

[Image gloss unevenness evaluation]
The gloss unevenness of the fixed image was evaluated by visually observing the gloss unevenness of the solid fixing image of the 10,000th fixing sheet. The criteria for evaluation of image gloss unevenness are shown below.
(Evaluation criteria)
A: solid image not having gloss unevenness B: slight gloss unevenness on a part of solid image C: gloss unevenness on a half area of solid image D: gloss unevenness was observed over the entire surface of the solid image.

[Surface evaluation of wrinkles]
During the endurance test under the above conditions, the presence or absence of wrinkles generated in the circumferential direction in the surface layer of the fixing member was visually evaluated. The criteria for evaluation of surface layer wrinkles are shown below.
(Evaluation criteria)
A: Wrinkles were not confirmed even after fixing of 10,000 sheets.
B: Minor wrinkles occurred after fixing of 10,000 sheets.
C: Wrinkles occurred in fixing of less than 1,000 sheets.
D: Wrinkles were generated or the surface layer was peeled off when the sheet was fixed.

Example 1
[Preparation of elastic layer]
100 parts by mass of liquid fluorine elastomer (SIFEL 2662, 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.)) are mixed and stirred Stirring was performed for 10 minutes using a degassing apparatus (AR-250, Inc., Inc.) and defoaming was performed for 1 minute to obtain an elastic layer material liquid.
After applying the obtained elastic layer material solution on a substrate (thickness 35 μm, diameter 24 mm) formed of SUS (stainless steel) so that the thickness of the cured rubber becomes 300 μm, 200 ° C. · The elastic layer was formed by curing under the conditions of 4 hours.

[Preparation of surface layer]
An amorphous fluorine resin solution (Somaflon B1, manufactured by Somar Co., Ltd.) having a structure of Formula (1) was applied onto the elastic layer by a spray application method. Thereafter, it was placed in a drying oven and heated at 110 ° C. for 10 minutes. The 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 is transferred 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 hole diameter was 90 nm, and the surface free energy was 12.1 mJ / m ² . Moreover, it was 7.4 * 10 < ² > ng when the adhesion amount was measured. In addition, when the heat resistance of the used fluorine oil was confirmed, the weight reduction 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 Corp.) under the conditions of a magnification of 50,000 and an acceleration voltage of 1.0 kV. FIG. 4 shows a SEM image of the surface of the fixing member according to this example.

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

(Example 3)
As a non-crystalline fluorine resin solution in the preparation of the surface layer in Example 1, except for using a non-crystalline fluorine resin (ALGOFLON AD 40H, Solvay Co., Ltd.) solution having a structure of formula (2) in place of somaplon B1. In the same manner as in Example 1, a fixing member was produced. The film thickness of the produced surface layer was 87 nm, and the hole diameter was 93 nm. The surface free energy was 12.4 mJ / m ² . Moreover, it was 8.4 * 10 < ² > ng when the adhesion amount was measured.

(Example 4)
As a non-crystalline fluorine resin solution in preparation of the surface layer in Example 1, instead of somaplon B1, a non-crystalline fluorine resin solution (Cytop A type, manufactured by Asahi Glass Co., Ltd.) having the structure of Formula (3) is used A fixing member was produced in the same manner as in Example 1 except that the fixing member was used. The film thickness of the produced surface layer was 89 nm, and the pore diameter was 93 nm. The surface free energy was 12.3 mJ / m ² . Moreover, it was 6.4 * 10 < ² > ng when the adhesion amount was measured.

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

(Example 6)
A fixing member was produced in the same manner as in Example 1 except that Krytox 107 (Kemers Co., Ltd., kinematic viscosity = 1,600 cSt (20 ° C.)) was used as the fluorine oil in Example 1 instead of Demnum S-200. The film thickness of the produced surface layer was 90 nm, and the hole diameter was 96 nm. The surface free energy was 12.1 mJ / m ² . Moreover, it was 3.9 * 10 < ² > ng when the adhesion amount was measured. In addition, when the heat resistance of the used fluorine oil was confirmed, the weight reduction rate was 0.6%.

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

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

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

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

(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 in place of Demnum S-200 as the fluorine oil in Example 1. The film thickness of the produced surface layer was 92 nm, and the hole diameter was 93 nm. The surface free energy was 12.4 mJ / m ² . Moreover, it was 7.8 * 10 < ² > ng when the adhesion amount was measured. When the heat resistance of the used fluorine oil was confirmed, the weight reduction rate was 8.3%.

(Comparative example 1)
[Preparation of elastic layer]
After applying liquid fluoroelastomer (SIFEL 2662, Shin-Etsu Chemical Co., Ltd. product) to a thickness of 300 μm after curing on a substrate (35 μm thick, 24 mm diameter) made of SUS, 200 ° C. An elastic layer was formed by curing under the conditions of 4 hours.

[Preparation of surface layer]
An amorphous fluorocarbon resin solution (Somaflon B1, manufactured by Somar Co., Ltd.) having a structure of the formula (1) was applied to the elastic layer by a spray coating method. Thereafter, it was placed in a drying oven and heated at 110 ° C. for 10 minutes. The surface layer was formed by further heating at 250 ° C. for 10 minutes. In this comparative example, since the elastic layer does not contain a fluorine oil, no migration of the fluorine oil from the elastic layer to the surface layer occurs in the process of forming the surface layer. The film thickness of the produced surface layer was 95 nm, and the pore diameter was 99 nm. The surface free energy was 13.1 mJ / m ² .

(Comparative example 2)
As a non-crystalline fluorine resin solution in the preparation of the surface layer in Comparative Example 1, a solution of non-crystalline fluorine resin solution (Cytop A type, manufactured by Asahi Glass Co., Ltd.) having the structure of Formula (3) is used instead of somaplon B1. A fixing member was produced in the same manner as in Comparative Example 1 except that the fixing member was used. The film thickness of the produced surface layer was 91 nm, and the hole diameter was 91 nm. The surface free energy was 13.4 mJ / m ² .

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

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

(Comparative example 5)
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 to the surface layer after producing the fixing member. The film thickness of the produced surface layer was 96 nm, and the hole diameter was 91 nm. The surface free energy was 12.3 mJ / m ² . Moreover, it was 7.6 * 10 < ² > ng when the adhesion amount was measured.

(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 as the fluorine oil in Example 1 in place of Denumam S-200. The film thickness of the produced surface layer was 97 nm, and the pore diameter was 90 nm. The surface free energy was 12.0 mJ / m ² . Moreover, it was 5.8 * 10 < ³ > ng when the adhesion amount was measured.

(Comparative example 7)
A fixing member was produced in the same manner as in Example 1 except that a dispersion paint (AW-5000L, manufactured by Daikin Industries, Ltd.) of PFA particles was heat-cured and laminated as a surface layer in Example 1. The film thickness of the produced surface layer was 99 nm, and no void was 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 porous PTFE resin (Poreflon, manufactured by Sumitomo Electric Fine Polymer Co., Ltd., pore diameter 220 nm) was laminated as the surface layer in Comparative Example 6. The film thickness of the produced surface layer was 1.2 micrometers, and the hole diameter was 220 nm. The surface free energy was 12.3 mJ / m ² . Moreover, it was 6.2 * 10 < ³ > ng when the adhesion amount was measured.

(Comparative example 9)
A fixing member was produced in the same manner as in Example 1 except that a porous PTFE resin (Poreflon, 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 produced surface layer was 7.8 micrometers, and the hole diameter was 1200 nm. The surface free energy was 12.1 mJ / m ² . Moreover, it was 28.5 * 10 < ³ > ng when the adhesion amount was measured.

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

(Comparative example 11)
A fixing member was produced in the same manner as in Example 1 except that 55 parts by mass of fluorine oil was used. A uniform surface layer could not be produced, and subsequent evaluations could not be made.

  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 understood. That is, according to the present invention, by supplying fluorine oil having high releasability to the surface layer having a porous structure made of fluorine rubber, even if the toner is a wax-reduced toner, it is possible to release the toner over a long period of time. It is possible. In addition, since the pore diameter of the surface layer is fine, the supply amount of fluorine oil to the surface can be controlled, so that adverse effects such as toner offset and image deterioration due to oil components can be suppressed. Recognize.

DESCRIPTION OF SYMBOLS 10 fixing roller 11 base layer 12 elastic layer 13 surface layer 15 halogen heater 20 pressure roller 21 core metal 22 elastic layer 23 releasing layer 100 fixing device T toner P recording medium

Claims (8)

A fixing member for electrophotography comprising a base layer, an elastic layer, and a surface layer,
The elastic layer contains a fluorine oil having a perfluoropolyether structure and a fluorine rubber,
The surface layer includes a fluorine resin and a fluorine oil having a perfluoropolyether structure, and has a porous structure having a plurality of pores,
The fixing member for electrophotography characterized in that the following condition (i) is satisfied:
[Condition (i)] A fluorine oil having a perfluoropolyether structure is absorbed and removed from the surface of the surface layer at a mass corresponding to at least the total mass of the fluorine oil contained in the surface layer, and subsequently When the detection surface of the quartz crystal microbalance (QCM) sensor is pressed against the surface of the surface layer for 50 msec at a temperature of 180 ° C. under a pressure of 0.4 MPa, a unit area of the detection surface ( The mass of the deposit including a fluorine oil having a perfluoropolyether structure attached to 1 cm ² ) is 1.0 × 10 ² ng or more and 5.0 × 10 ³ ng or less.   The porous structure possessed by the surface layer is contained in the elastic layer such that the deposit attached to the detection surface includes a fluorine oil having a perfluoropolyether structure contained in the elastic layer. The fixing member according to claim 1, wherein the fluorine oil is allowed to pass in the thickness direction of the surface layer.   The fixing member according to claim 1, wherein the fluorine resin contained in the surface layer contains a cyclic perfluoropolyether resin.   The fixing member according to any one of claims 1 to 3, wherein an average pore diameter of pores in the surface layer is 1 nm or more and 200 nm or less. The absolute value of the difference in solubility parameter between the fluorine rubber contained in the elastic layer and the fluorine oil 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 to 4.   The fixing member according to any one of claims 1 to 5, wherein the fluorine oil has a weight reduction rate of less than 1.0% after being heated at 250 ° C for one hour in the atmosphere.   A fixing device comprising the fixing member according to any one of claims 1 to 6. An image carrier,
A charging device for charging the image carrier;
An exposure device which irradiates exposure light to the charged image carrier to form an electrostatic latent image;
A developing device for developing the electrostatic latent image formed on the image carrier with toner to form a toner image;
A transfer device for transferring a toner image formed on the image carrier to a recording medium;
A fixing device for fixing the toner image transferred to the recording medium;
An electrophotographic image forming apparatus, wherein the fixing device is the fixing device according to claim 7.